Marketing Research assignment 5 Example | Topics and Well Written Essays - 250 words

Marketing Research 5 - Assignment Example se logarithms to envision ROI (return on investment .Mathematical difference refers to the percentage acquired after computing the difference between your merchandise cost and the selling price. The larger the difference for instance 70%, the less profit gained because of competition from other companies. Basically, managerially important difference refers to variation in preferences used by company management concerning price and output decisions, choice and techniques of production, demand estimation, investment decision, and long run production decision (Vikram 8). These differences in management may or may not lead to adjustment in changes and invention of new ideas. Organizations that recruit managers with different qualities and capabilities based on different approache to situational factors are at high chances of profiting because of the divergent ideas. On the other hand, statistical significance is a test that determines if marketing research reports are significant or incidental. They include chi-square tests, t-tests, and z-tests which studies relationship between two categorical variables. The level of significance used is 0.10 or 0.05. A result with level of significance of 0.1(90%) indicates statistical significance. To determine if its incidental you check the sample size and determine the margin of error; P (Z=

Effects of Classical and Post-Classical Religions Research Paper

Effects of Classical and Post-Classical Religions - Research Paper Example With the fall of the empires and their economies, the people had to find means to live and believe in order to proceed with their normal lives. People then got the chance to migrate to different areas and meet new people, develop new ideas and learn new and diverse ways of life. Religion would not have come at a better time for them since it enabled them have a venue to express their beliefs and needs. Christianity being one of the religions was embraced by people and they henceforth developed allegiances in accordance with the different religions that they embraced. Eastern mediteranian, for example, enjoyed the aftermath of the Roman empire’s collapse as it opened trade and opportunities for them . Politically, the rise of Christianity saw changes in leadership styles and allegiances. The previous empires like the Roman empire always dictated and demanded that people worked with allegiances sworn to the leardership. This changed with the belief that were embraced by the chri stian teachings. The teachings enabled and required people to work together with others to collectively help improve their lives and in unity to build a strong kingdom of God . The supreme being was nolonger the emperor, but God. These religious people happened to be in regions that identified with the religion that was more dominant. Christianity did institute within its gorvenance structure and formation tactics borrowed from the Roman empire. Cultural and artistic ways and lives of people also changed.... The teachings enabled and required people to work together with others to collectively help improve their lives and in unity to build a strong kingdom of God 3. The supreme being was nolonger the emperor, but God. These religious people happened to be in regions that identified with the religion that was more dominant. Christianity did institute within its gorvenance structure and formation tactics borrowed from the Roman empire. Cultural and artistic ways and lives of people also changed with the transition of the society into the religions of salvation. The Roman empire, for instance, had their gods that they would offer sacrifices to in times of their needs. They belived that the gods were many and that every god had a purpose, authority and power to reward and punish those who did not heed to or obey them. Christianity, on the other hand, came up with the teaching that the last sacrifice was that of the death of Jesus Christ and that there was only one GOD 4. This brought about c onflict of interest and cultural discomforts, as well as disagreements between the emperors and the christians resulting in christians being prosecuted. Christianity introduced a way of life in which people lived together in harmony and peace. It brought forward a community that preached against violence and discrimination. On the other hand, the previous empires used coercion, divide and rule kind of leadership that only benefited those in power. Social lives of the people received a great change and boost, one that the people found easy to embrace as it cared for the well being. However, the leadership was immensely affected since their ways of gaining more power and strength was being overshadowed by the strong beliefs that the people developed.

Parental Substance Abuse And Safeguarding Children Social Work Essay

Parental Substance Abuse And Safeguarding Children Social Work Essay Substance misuse causes considerable harm and is presently an immense global issue of public concern. It is a wide-ranging problem, damaging individuals, families and entire communities. In general, substance misuse is not only growing considerably within the United Kingdom, but also worldwide. Simultaneously, the number of children involved in the vicious circle of drug taking and problem drinking by their parents is also increasing. Although governments, policy makers and practitioners are recognizing the problem and taking steps towards tackling the effects of substance abuse within families; the issue in general seems far from being solved. Alcohol is legally available and easily accessible throughout England. It is positively associated with socialising, relaxing and celebrating. Although problems linked to excessive alcohol consumption are widespread and well established, it seems that alcohol misuse is somehow more socially accepted and does not have the same stigma as using drugs. Consequently, the issue of alcohol abuse, especially in families with children, often remains undiscovered, and the negative impact and effects of the excessive drinking behaviour of parents on children remain under-recognized and neglected. Estimates by the Prime Ministers Strategy Unit (2004) are that between 780,000 and 1,3 million children in England are (in)directly affected by an alcohol problem of at least one parent in other words: 1 in 11 children live in a household where alcohol misuse is present. While alcohol and the negative consequences associated with its uncontrolled use have been around and well documented for centuries, the drug industry has only been developing and growing rapidly over the last few years. Concordant with the Advisory Council on the Misuse of Drugs (2003) up to 300,000 children or 3% of all children under 16 currently belong to a family where one or two of their parents struggle with a dangerous drug issue. Parental substance misuse is also not unheard of in social services caseloads with one quarter to one third of families known to social services as being involved with misusing drugs or alcohol (Cleaver et al., 1999; Kearney et al., 2003). Many of these children do at least temporarily not live with their addicted parents. Putting these figures together, more than 10% of all children in England are exposed to suffer under the effects of their parental drug or alcohol misuse and it is extremely likely that these numbers will continue to grow over the following years. It seems also reasonable to believe that the official figures of affected children may be under-estimating the true scale of the problem as it is extremely difficult to calculate how many families have to cope with some form or the other of substance abuse (Templeton, 2006). First, not all drug and alcohol services take proper care to establish whether or not their clients are also parents and second, not all clients are willing to provide information about the existence of own children. Third, some institutions do not disclose figures, collect data properly or tend to under-report; and fourth, nobody knows how many substance misuser are not seeking treatment and, therefore do not appear on any official statistics (Keen et al., 2001; ACMD, 2003). Consequently, missing data and a clear underestimate of the total number of affected children by parental substance misuse seem obvious. Substance abuse can include negative physical (such as health risks and neglect), psychological (such as attachment disorders and depression) as well as social (such as poverty and crime) influences on both parents and their children (Kroll et al., 2000). Parental alcohol and drug abuse can affect childrens health and development in the long term from as early as conception and often into adulthood, leading to varying forms of strong, adverse and complex consequences (Turning Point, 2006). Additionally, all conceivable types of child maltreatment have repeatedly been associated and clarified in various studies with parental substance abuse including negligence (as the most common type of abuse), sexual, emotional and physical abuse (Cleaver et al., 1999; Alison, 2000; Forrester et al., 2006). The impact of alcohol and/or drugs may also significantly affect the parents capacity of adequate parenting (Alison, 2000). The negative impact of a dependency on the substance misuser himself can lead to chaotic lifestyles, complicating and preventing parents to support and care for their own children, meeting their basic needs and providing a safe and encouraging home environment (Keen et al., 2001; Home Office, 2008). With the knowledge that parental misuse of certain substances can have a seriously negative impact on childrens physical, psychological and emotional health and development, it is essential that these children potentially at risk are identified as early as possible in order to arrange for appropriate protection and safeguard their welfare (Nottingham City, 2004). This is the responsibility of all professionals in different ranges of services; they all must be able to identify and treat substance misuse related problems by adults, and also focus on the problems of affected children (Keen and Alison, 2001). Therefore, increasingly more research is being done, policy initiatives started and family-supporting services and projects have developed rapidly (Templeton et al., 2006). Although considerable progress has been made in recognizing and tackling the problem of substance abuse and the issue has won much public awareness in the last years, sadly, the death of children through the hand s of their parents recalls that the system still fails to safeguard children at risk. Professionals face a variety of often complex issues and struggle with working unimpeded. The most common problems are a lack of understanding, gaining access to the substance misuser and their children, resilience, dilemmas about confidentiality and information sharing, inter-agency tensions, assessment, lack of training and the ability to focus on both, adults and childrens needs (Kroll and Taylor, 2000; Taylor and Kroll, 2004). Without a doubt, changes and new approaches are needed, and through joint assessment, better information sharing and inter-agency cooperation, the focus should be on effective intervention and treatment for the substance misuser as well as of the so far often invisible and neglected children (Kroll and Talyor, 2000; Head of Safeguarding Children, 2008). The first section of this essay describes effects and causes associated with parental substance abuse. It highlights the impact of drug and alcohol misuse on the foetus during pregnancy and later on the child from newborn to adulthood, as well as resilience and protective factors for affected children. Part two focuses on professionals: their responsibilities regarding childrens safeguarding and the challenges they face when confronted with substance misuse. The third section covers the legal framework of safeguarding children and other related political measures. The fourth section examines the progress made so far by looking at different projects, interventions implemented and recent developments. In contrast, section five gives an insight into reality, pointing out some of the most obvious problems and recent incidents. It touches thoroughly discussed issues such as information sharing, inter-agency cooperation and training. The last section considers aims and goals, their impleme ntation and suggests recommendations for a more effective strategy in the future. Throughout this article substance misuse/abuse refers to the use either dependant use or associated with adverse effects of prescribed (such as tranquilizers, sleeping pills, pain-killers, depressants) and illicit (such as opioids, cocaine, ecstasy, cannabis) drugs as well as alcohol (Newcastle Child Protection, 2002) with critical social, interpersonal, financial, physical and psychological negative effects for both the users and those around them (ACMD, 2003). 78 SUBSTANCE MISUSE AND EFFECTS ON PARENTS AND THEIR CHILDREN There is reasonable basis in research to suggest that a child whose parent is misusing substances is at increased risk. Substance misuse can demand a significant proportion of a parents time, money and energy, which will unavoidably reduce resources available to the child. Substance misuse may also put the child at an increased risk of neglect and emotional, physical or sexual abuse, either by the parent or because the child becomes more vulnerable to abuse by others (Lewis, 1997) Parental substance abuse does not necessarily mean that children are at risk of harm or in need or receive poor parenting in some cases they would not even be affected in a negative way (Newcastle Child Protection, 2002). However, only a few children will not have to deal with multiple, mounting and varying negative consequences and survive such a complex issue entirely unscathed. While a concrete pattern of effects can never be clearly determined due to the complexity of the issue, many of the children may be permanently affected in an adverse manner, either emotionally, physically, socially, intellectually or developmentally (ACPC, 2004). Problems include a variety of health and developmental issues, ineffective parenting, criminal activity, poverty, chaotic lifestyles and educational attainment, and have long been underestimated and an abandoned research field (Keen and Alison, 2001; HM Government, 2008). The Children Act (1989, s17 (10)) defines a child in need as unlikely to achieve or maintain, or to have the opportunity of achieving or maintaining, a reasonable standard of health or development without the provision for him of services by a local authority; his health or development is likely to be significantly impaired, or further impaired, without the provision for him of such services; or he is disabled. In this context harm means ill-treatment (sexual abuse and forms of ill-treatment which are not physical) or impairment of health (physical or mental health) or development (physical, intellectual, emotional, social or behavioural development) (The Children Act 1989, s31 (9)). Among hundreds of other prescribable substances, alcohol and opiates should be reduced or avoided at all during pregnancy. Although it is not possible to evaluate all the effects of drugs and alcohol to a full extend on a fetus, it is known that it can be damaging at any time during pregnancy (from conception onwards up to birth, with the first 3 months being particularly vulnerable), causing a variety of health and development problems. Babies whose mothers were dependant on opiates or alcohol during their pregnancy are more likely to be smaller, of lower birth weight, premature and at higher risk of the sudden infant death (ACMD, 2003). Additionally the addicted mothers affected health and her possibly poor nutrition (high levels of sugar, not enough calcium, proteins, fruits and vegetables) often have an additional negative impact on the fetus physical and psychical development and the babys health. If an unborn is exposed to maternal alcohol abuse, this cannot only lead to the familiar serious impairments related to substance abuse mentioned before, but also to a remarkably common developmental problem known as Foetal Alcohol Syndrome. Foetal Alcohol Syndrome includes a series of potential effects on children such as learning disabilities, heart defects, lower body weight, decreased height, facial deformities, vision and hearing difficulties, ADD (Attention Deficit Disorder), ADHD (Attention Deficit Disorder with Hyperactivity), conduct disorder and inappropriate behaviour (Dore et al., 1995). Expecting women sharing injection equipment or working as prostitutes to finance their drug use, live with the constant threat of being infected with HIV or hepatitis B; for children born to drug dependent mothers who are infected with HIV, hepatitis C or hepatitis B, there is also a remarkably elevated risk to be also infected during pregnancy, birth or while being breastfed (ACMD, 2003). Heavy and prolonged maternal substance abuse, both opiates and alcohol, will very likely expose the child to the Neonatal Abstinence Syndrome, which is a term for a range of problems a newborn may encounter when withdrawing from exposure to narcotics. Typical symptoms include high-pitched and excessively long periods of crying, shivering, sneezing, sweating and temperature, vomiting and diarrhea, feeding difficulties, disturbed sleeping patterns, convulsions,, irritability and hyperactivity, high sensitivity to touch, wild sucking, rapid breathing and cardiac action (Marcory and Harbin, 2000). Despite the chance that appropriate antenatal care from the beginning would increase the possibility of a healthy and normal pregnancy and satisfactory development of the fetus, mothers involved with substance dependence often do not seek antenatal care, particularly due to their fear of being stigmatized. (Newcastle Child Protection, 2002). As a baby grows older, the likelihood of experiencing some negative consequences due to its parents substance abuse is not diminished in any way and the impact will vary considerably, depending on several factors such as the childs age and stage of development. The establishment of a decent, confident and secure relationship to at least one caregiver in the early months has widely been recognized as the foundation of a childs normal development. However, children of substance misusing parents often experience parental unavailability, inconsistent care and conflictual relationships (ACMD, 2003). A habit often lets a parent focus more on acquiring and using his drugs or alcohol rather than its childrens needs. Intoxication and coping with withdrawals symptoms lead to limited time, attention and emotional unavailability (Kroll and Taylor, 2000). Further, children of drug and alcohol abusers often have to experience an enforced temporary or permanent separation or loss of a parent due to abandonment, hospitalization, imprisonment, treatment, removal or other emergencies (ACMD, 2003). All these points contribute to life-long complicated and insecure attachment. The above-specified problems commonly also affect the nature and quality of parenting, which in turn often naturally results in further difficulties in a childs development (ACMD, 2003). Research proves that many substance abusing parents lack exemplary models for parenting as they have received poor parenting and maltreatment themselves (Keen and Alison, 2001). As dependence on a substance becomes central, parents are more likely to neglect their children which bears various risks and dangers them, regardless of their age group. Children may be inadequately supervised or left alone at home, exposed to preventable accidents and/or injuries (Kroll and Taylor, 2000). But not only children are at risk of accidents, also drugged or drunken adults are exposed to a higher level of self-induced incidents such as falls, forgetting food on the hob or falling asleep with still glowing cigarettes. Parents with an addiction repeatedly also tend to be unable to fulfill their childrens own basic needs so daily hygiene, a balanced diet and general health may suffer as well as stability, routines (such as bedtimes, getting up and out for school) and boundaries (Alison, 2000). Further health risks may be provoked not taking childrens routine health appointments or problems seriously enough or careless disposal and therefore easy access to drugs, bottles, syringes and needles (Kroll and Taylor, 2000; Alison, 2000). There is also notable danger for children that have observed their parents using substances, copying them (ACMD, 2003). Girl, 2, dies drinking her mothers methadone (2002) Boy, 2, died after taking parents methadone (2006) Boy, 14, dies after drinking methadone at his aunts flat (2008) Another consequence of parental unavailability is that children are often left alone with daily adult/parental responsibilities such as caring for their younger siblings, meeting their parents needs, managing finances and household chores (Kroll, 2004). Such additional and inadequate responsibilities may in turn result in the loss of social opportunities and poor academic performance of child- some research gives evidence that children miss school (regularly) by being kept at home due to caring responsibilities and left with little time to socialize. Social isolation becomes more severe as the child grows older and starts to be careful about exposing family life to outsiders and lives in a circle of denial and secrecy due to shame and fear (ACMD, 2003). Misusing drugs or alcohol does not only contribute to negligence but often goes hand and hand with other forms of child abuse and violence at home. The possibility of abuse and child maltreatment is enforced by the likelihood that children may be exposed to a number of possible dangerous strangers or inappropriate carers within their own home (Newcastle Child Protection, 2002). Research also reveals a lower tolerance level and moderate loss of temper associated with substance abuse, causing aggressive behaviour and resulting in violence to appear frequently (Kroll, 2004). Emotional neglect and abuse is also an issue within a parental substance misusing environment. Children often either feel rejected and unloved by their parents as they concentrate and spend considerably more time on their destructive habit than with them, or embarrassed and often also guilty (Kroll, 2004). Maintaining an addiction is a financial burden, not only making it difficult to complete household costs, but also regularly leading to criminal activity to buy drugs or alcohol. Children of addicted parents are also more likely to be exposed to early criminal conduct and/or its consequences not infrequently because they have been with a parent while they had been committing a crime (ACMD, 2003). Although parents try and tend to hide their habit from their children, children sooner or later discover it and typically have to deal with it by themselves which usually adds to a variety of already existent behavioural problems due to the mentioned consequences of parental substance abuse children tend to be more aggressive, feel upset or anxious and show anti-social behaviour (ACMD, 2003). Negative parental examples and role models such as drug taking, alcohol abuse, crime, poor living conditions and inappropriate behaviour inevitably can lead a child to view their parents actions as being normal and approved so that substance abuse and outrageous conduct by themselves becomes more likely as they enter into their teens and adulthood (ACMD, 2003). Research into child resilience has shown that key protective factors can have an enormous impact on preventing children from being damaged by parental substance misuse. The field of factors includes having a parent not misusing substances, a strong bond with a caring adult and support from extended family (Templeton and Velleman, 2007). Further to mention are a violence-free home, sufficient financial resources and an upstanding support system as well as educational success and involvement in different activities (19?). Working towards personal goals and dreams, taking education or career opportunities or even leaving the parental home are also common strategies to deal with experiencing substance abuse at home (Templeton and Velleman, 2007). Parents generally are aware of the negative consequences and influence on their children, and they often experience a range of impacts as a result of their weakness which moreover will have follow-on affects for their children, for example in their parenting capacity. Many of them have experienced difficult childhoods and were poorly parented themselves in this cases drugs or alcohol are often used to deal with a range of traumas and tension associated (Alison, 2000). PROFESSIONALS It is the reliability and function of all genres of professionals and agencies including general practitioners, health visitors, doctors, midwifes, pediatricians, mental health services, family support services, treatment institutions, social services, police, educational settings and voluntary sectors to safeguard and protect children. Safeguarding is equal to keep children safe from harm and abuse both deliberate abuse as well as accidents, bullying and crime and to promote their well-being and development in a healthy and safe environment (HM Government, 2006). Everyone having contact with children must be aware that it is not acceptable to remain sidelined if a child is in need or risk of harm (Lord Laming, 2003). However, it is noteworthy that each professional recognizes and accepts the limitations of his own roles and values the essential share of others (Keen and Alison, 2001) otherwise everyones duty and the mission to put a childs welfare first soon gets lost and remai ns no ones responsibility (Inter-Agency Guidelines, (2008). Challenges When encountering parental substance abuse, all professionals face a series of dilemmas, conflicts and tensions in their work with children and adults. They often simply feel unprepared and lack the expertise, skills and training to focus and work effectively with adults and children to the same purpose, and even if they do have the proper training, professionals often just do not see their role in engaging with children or substance misusing parents (Templeton and Velleman, 2007). Professionals interviewed by Taylor and Kroll (2004) stated one after another that they lack training which covers child safeguarding and protection processes and feel inexperienced to work with children of drug and alcohol users, children in need or risk of harm. Additionally, there seems to be a common confusion among different agencies regarding their individual roles and therefore allocation of clear responsibilities. A large part of these issues lay in the individual and independent development of sub stance misuse services and child welfare approaches over the last years. While adult treatment services place the substance abusers first and often do not involve existing children, the primary purpose of child protection agencies are solely the children, generally not taking into account parents needs (Colby and Murrell, 1998 in Taylor and Kroll, 2004). But agencies working with children must also take into account the situation and the problems of the respective parents, being aware of the impact parents behaviour have on children. At the same time, services for adults must not ignore existing children, so a great cooperation between agencies and services is needed (Templeton and Velleman, 2007). Professionals and agencies have to deal with parents who may bot be easy to engage with, who may not want to cooperate with them, are reluctant to open up, tell the truth or prepare to change (Nottingham City ACPC, 2004). Therefore it can be a challenge to obtain, establish and maintain t rusting relationships with either the parents or the effected children (Inter-Agency Guidelines, 2008). On the other hand, families with a drug and/or alcohol problem fear a range of consequences and rejection by opening themselves to professionals, which usually keeps them in a twist of silence and secrecy, thus preventing them access to support and help for themselves or their children (Nottingham City ACPC, 2004). Parents are often reluctant to approach services and seek treatment, have problems to confide in others and reveal their drug and/or alcohol problem as they particularly fear that any disclosure could lead to losing their children and that their family might be treated differently, stigmatized or denied by others (Nottingham City ACPC, 2004). Although confidentiality is a key principle for such agencies, no organization can guarantee it and in some cases, professionals have to share information, especially when a childs welfare is at risk (The Stella Project, 2002). SAFEGUARDING AND LEGAL FRAMEWORK As mentioned earlier in this article, agencies, services and professionals in touch with children or/and adults who are parents have a variety of responsibilities to safeguard children, assess their needs and promote their welfare. In the United Kingdom, considerable legislative framework exists for this purpose, with the Children Act 1989 and the United Nations Convention on the Rights of the Child as the elementary and reforming pieces of child law. In general, the Children Act (1989) focuses on improving childrens lives and demands comprehensive services to all children as well as tailored ones for those with additional needs. It also clarifies that if a local authority has reasonable cause to suspect that a child who lives, or is found, in their area is suffering, or is likely to suffer, significant harm, the authority shall make, or cause to be made, such enquiries as they consider necessary to enable them to decide whether they should take any action to safeguard or promote tha t childs welfare (The Children Act 1989, s47 (1)). The Children Act also provides the legal grounds for the five Every Child Matters (2003) outcomes in law be healthy, stay safe, enjoy and achieve, make a positive contribution, achieve economic well-being. Later the Children Act (2004) implemented a requirement for local authorities and a range of agencies engaging with substance abusing parents to rank first the welfare and safety of their children. Local authorities and agencies are made responsible to determine if a child is in need and/or risk and then to take appropriate steps to protect him from (further) significant harm (ACMD, 2003). Further The Children Act (2004) focuses on co-operation to improve and secure the well-being of children. Early awareness and intervention is critical to reduce the numbers of child protection cases but assessment is an immensely complex process. When assessing the welfare of a child, practitioners must work sensitively and child-centred, analysing the parental substance misuse from the childs position to better understand the impact upon his development and life (Lord Laming, 2003). For a more standardized, coordinated, early and practical way to assess childrens individual needs, the Common Assessment Framework (CAF) was designed and forms part of the Every Child Matters (Lord Lamming, 2003). The Department of Health also provides the Framework for the Assessment of Children in Need and their Families, which is based on a more ecological approach. Further, all local authorities are required to have an Area Child Protection Committee to organize and supervise child protection measures. When determining that a child is at risk of significant harm, child protection procedures should immediately be initiated to ensure that the necessary referral is made to the social services (ACMD, 2003). It is crucial that assessment is ongoing and changes are carefully monitored when a parent is in treatment or free from drugs or alcohol dependence it does not necessarily mean that children do not longer suffer from any adverse consequences (Nottingham City ACPC, 2004). Further, if no concerns regarding the well-being of a child are established, professionals should remain in connection with the family and carefully observe them as harmless situations often quickly change into an unpredictable environment for the child (Newcastle Child Protection, 2002). PROGRESS Over the last years, there has been a wide range of Government initiatives, programmes, strategies and policies aimed at tackling (parental) substance misuse. The Updated Drug Strategy for England 2002, Models of Care for Alcohol Misusers, the Green Paper on Children at Risk, Extended Schools, the Childrens National Service Framework, Sure Start and Early Excellence Centres, mentioned above, are only some examples of key initiatives (ACMD, 2003; The Stella Project, 2002): The Updated Drug Strategy for England in general specifies a variety of actions undertaken by the Government to tackle drug use and restrict the access to Class A (heroin, cocaine) drugs. Further it acknowledges that there is not enough attention given to children of drug dependent adults and thus more focus on helping them as well as addicted mothers is needed. The Models of Care for Alcohol Misusers first effort is to identify, work towards and minimize negative consequences of alcohol abuse on children. In particular, this strategy also addresses abuse and domestic violence as the main associated problems with alcohol dependence. The Green Paper on Children at Risk is a strategy addressing a series of key recommendations of the Laming Report and aiming to implement policies to improve the life chances of children. The concept behind the Extended Schools project, initiated by the Department for Education and Skills, is that schools could create stronger relationships parents and children, motivate their pupils and so raise standards by offering a wider service such as adult education, health services and childcare. The Childrens National Service Framework main goal is to reduce inequalities in health and social services as well as upgrading the overall standard of such services. The scheme specifically concentrates on the needs of children of drug and alcohol abusers. Sure Start provides different services and support of all kind to all families in more disadvantaged areas and in cases of parental substance misuse, the Sure Start team will seek advice, refer to and work closely with the relevant practitioners and agencies. Early Excellence Centres were established to raise childrens welfare and development by working coordinated with other community agencies and offering advice, support, childcare, health services and early learning. With a comprehensive legislative framework already established in the United Kingdom and several initiatives and programmes running, it does not seem especially needed to modify existing legislations or implement new ones or start more projects to protect children effectively. Nevertheless, those already existing must be fully understood and applied by practitioners in all areas, and everyone must clearly understand his responsibilities and those of the others (Lord Lamming, 2003). However, the death of the children Baby P and Victoria Climbià ¨ are tragic examples of the failings in the child protection system. Despite considerable commitment and progress made so far, challenges remain in the protection of children and their safeguarding as well as in the daily reality of practitioners. The issues mainly surround training, adequate levels of staffing, improvement of data systems and information sharing and better coordination and cooperation problematically (Lord Lamming, 2003). REALITY The exact number of minors suffering under parental substance abuse known to social services is not clearly determined. In 1999, Cleaver et al. estimated that around 25 to 60 percent of all children in child protection proceedings were living with a parent having a drug or alcohol problem. A more recent study of 290 child custody cases in four different London boroughs revealed that 34% (100 families) where affected by substance abuse, resulting in more than 50% of all children in care proceedings and over a third of all children on the child protection files being subjects of parental substance abuse (Forrester and Harwin, 2006). Both researchers also found that most affected children were under the age of five years. Information sharing Although the government set clear guidelines on sharing information with the publication of Information sharing: Guidance for practitioners and managers in 2008, breaching confidentiality, information sharing and data protection still remain some o

Corruption and Failure in F. Scott Fitzgerald’s The Great Gatsby :: Great Gatsby Essays

Corruption in The Great Gatsby      Ã‚   The theme of human corruption, its sources and consequences, is a common concern among writers from Shakespeare through J.D Salinger. Some suggest that it attacks from outside, while others depict corruption occurring from within the individual. In the case if The Great Gatsby and it's protagonist's fate, Fitzgerald shows both factors at work. The moral climate of the Roaring Twenties, Daisy Fay Buchanan's pernicious hold on him, and Jay Gatsby's own nature all contribute to his tragic demise.      Ã‚  Ã‚   First, the loose morality of Dan Cody, Gatsby's unfortunate role model, and superficial people who flock to Gatsby's parties contribute to Gatsby's downfall. Their examples encourages Gatsby's interpretation of The American Dream- his naive belief is that money and social standing are all that matter in his quest for Daisy. The self-absorbed debetants and their drunken escorts are among those who "crash" his extravagant soirees. As Nick Carroway tells us, "People were not invited- they went there." (pg.40) Shallow, corrupt people like Jordan Baker gossip with reckless abandon about their mysterious host. Their careless, superficial attitudes and wanton behavior represent Fitzgerald's depiction of the corrupt American Dream.      Ã‚   Another force of corruption responsible for Gatsby's fate is his obsession with a woman of Daisy's nature. Determined to marry her after returning from the war, he is blind to her shallow, cowardly nature. He is unable to see the corruption which lies beyond her physical beauty, charming manner and playful banter. That she is incapable of leaving her brutal husband, Tom, of committing herself to Gatsby despite his sacrifices escapes him. As Nick observes, Gatsby's expectation is absurdly simple:"He only wanted her to tell him [Tom] that she never loved him." (pg.91) Daisy is not worthy of the pedestal on which she is placed. Since she is hallow at the core, so is his dream which is based on a brief flirtation, nothing more.      Ã‚   Finally, Gatsby's own character-especially his willful obsession-contributes to his fate. Despite his naivetà © about Daisy and her friends who "are rich and play polo together," he, too, has been seduced by the lure of money and fame. Unable to control his obsessive desire to have Daisy, he cares little about the

The Steps in the Business Buying-Decision Process

First process is problem recognition in which someone in the company recognizes a problem or need that can be met by acquiring a good or service. It can result from internal (a machine break down and need new parts) and external stimuli (buyer receive a call from a salesperson who offers a better machine or a lower price). Next stage is general need description in which a buyer describes the general characteristics and quantity of a needed item.An example, for complex items, the buyer needs to work with others-engineers, users, consultants to define the item. Third step is product specification. The buying organization decides on and specifies the best technical product characteristics for a needed item by using product value analysis. Supplier search is another step in which the buyer tries to find the best vendors. They can compile a small list of qualified suppliers by reviewing trade directories, doing computer searches, or phoning other companies for recommendations.Another stag e is proposal solicitation. In this stage the buyer invites qualified suppliers to submit proposals. Business marketers must be skilled in researching, writing, and presenting proposals in response to buyer proposal solicitation. Next step is supplier selection in which the buyer reviews proposals and selects a supplier or suppliers. The buying center often will draw up a list of the desired supplier attributes (product and service quality, reputation) and their relative importance.Order-routine specification is the next step of business buying-decision process. the buyer writes the final order with the chosen supplier(s), listing the technical specifications, quantity needed, expected time of delivery, return policies, and warranties. Final stage is performance review in which the buyer assesses the performance of the supplier and decides to continue, modify, or drop the arrangement. The seller’s job is to monitor the same factors used by the buyer to make sure that the sell er is giving the expected satisfaction.

Power of One Word

A single word can be used to belittle, hurt, and humiliate. One word can cause so much hurt to a person that they burst into tears or spiral down into a damaging hole that they can't get out of for an extended amount of time. Throughout history, names have been used to keep a population in its place. Insults have been hurled to make a single person understand what another thinks of them. Words are used all the time to cause damage to a person or an entire peoples soul. One word can have a lot of power. In â€Å"What's in a Name? †, Henry Louis Gates father was a well respected negro in his community.Maybe the better way to put it is more respected. He worked two jobs, and being more financially successful elevated the family's status. The Gates family was the only negro allowed into a local drugstore to actually sit down and eat. On one occasion, Mr. Gates and his father went in together for ice cream and his father greeted a white man. The white man, Mr. Wilson, responded, bu t called his father â€Å"George†. George was a disparaging name for black men. Mr. Gates asked his dad to correct the Mr. Wilson, thinking it had been a mistake. When he realized that Mr.Wilson had deliberately insulted his father, it changed something in him forever. I believe Mr. Gates could not comprehend Mr. Wilson acknowledging and belittling his father at the same time. Why did he say anything back at all? Why would he be rude on purpose? Mr. Gates, up until that moment, had believed that Mr. Wilson was a nice person. After Mr. Gates' father explained that he called every black man George, his opinion shifted. The white man insulted every black man he knew. This was the first time Mr. Gates could see that people were not always who they seemed.He was confused about why his father did not correct Mr. Wilson. Surely his father must have been insulted. He must have understood that Mr. Wilson meant to insult him. I believe he became embarrassed for his father and wanted hi m to correct Mr. Wilson, to stand up for himself. His mother called it â€Å"just one of those things† (Gates 6), and he was upset that they accepted that. It was painful that they had so many of those moments. He wanted his father to change something, to correct the wrong. Accepting it was painful and shameful. He wrote that he could never look Mr.Wilson in the eye again. One word, â€Å"George†, made a little boy see clearly a white man, his black father, their positions in society, and the injustice that society tolerated. It changed his view of the world and of his family forever. In A Lesson Before Dying, a black man, Jefferson, is sentenced to be electrocuted for a murder that he did not commit. He was in the wrong place at the wrong time with a couple of boys he had known his whole life, and they were trouble. They robbed a liquor store that was owned by a white man, and during the robbery the white man was killed.A black man at the scene of the crime never stoo d any chance of not being convicted. When the sentencing part of his trial came up, his lawyer tried to get him out of a death sentence. The lawyer claimed that he was the equivalent of a hog. â€Å"I ask you, I implore, look carefully- do you see a man sitting here? † (7; pt. 3, ch. 1)†¦ â€Å"What justice would there be to take this life? Justice gentlemen? Why, I would just as soon put a hog in electric chair as this. † (8; pt. 4, ch. 1) Jefferson and his godmother, Aunt Emma, are both deeply affected by the word hog.She calls on a family friend, Grant, to help Jefferson learn to be a man. She says, â€Å"I don't want them to kill no hog† and â€Å"I want a man to go to that chair, on his own two feet. † (13; pt. 2, ch. 2) She wants him to die with dignity. The first time they see him after the court date, Jefferson has taken being a hog to heart. He's so hurt that he snuffles and makes hog noises, saying that dignity is for â€Å"youmans† (83; pt. 8, ch. 11) and they should only be bringing certain foods that hogs eat, since he was a hog. Grant has no idea how to teach dignity to a man, but over time they start to communicate.They talk about ice cream, which Jefferson wants for his last meal, and Grant brings him a radio. This reminds Jefferson of his humanity, and he thinks maybe Grant is trying to do him some good. Grant had been struggling with his own demons since he came back to his hometown after college. He no longer believes in God and is bitter and beat down by the way black people are treated. He separates himself from his community because he thinks that he no longer belongs. He thinks that his family and friends don't understand how white people keep them all in their place, and that they are weak because they just accept it.He never wanted to help Jefferson and thought he would never be able to make a difference. Breaking through to Jefferson makes him realize that as much as he hates the way life is in their small town, he does belong. He is a part of it and the people. He can finally understand what Jefferson's aunt wanted him to do, and explains to Jefferson that he can die a man, that Jefferson can go to the chair with so much dignity that he strengthens the whole community. They all owe something to each other, and like it or not, they should all be trying to help each other out.Jefferson realizes that since he loves his aunt he should learn to â€Å"be a man† so she can have peace when he dies. When he finally goes to the chair, he is a man. He dies with dignity and leaves his mark behind. White men know deep in their hearts that his punishment was unjust. He starts a slow change in certain people in that town. Jefferson left behind more than he had brought with him to the world. One word, â€Å"hog† changed two men forever. Jefferson found himself and became something for the people to look up to. Grant realized that he was not better than everyone else, and be gan wanting to make his world a better place.The word hog took Jefferson down so low that he believed he should be eating slop off the floor and that they should just hurry up and slaughter him. When his time finally came, he was calm and understood that he could actually use this to do some good. He was a man. Females can be horrible to each other. They can be vicious and sneaky, and sometimes that is most evident in sororities. Sororities have intense and sometimes demeaning tasks and initiations to become a member. The older girls will tell their pledges that they are losers, fat, or stupid.There is one word that seems to be thrown out more often than not, and it should be a word that women don't use against each other, â€Å"bitch†. The girls that pledge to sororities are looking for somewhere to belong when they get to a new school and are away from home for the first time. In a lot of cases, instead of being welcomed and introduced to their new school in a friendly way, they are put through hazing and degrading situations. In Pledged, one of the initiations was putting the new girls in blind folds, stripping them down and laying them face down on the floor.Boys from a fraternity were then free to move around the room with markers and mark on the girls. The boys would highlight the areas on their bodies that the new girls needed to work on. (Robbins 259-260) Others sororities have branded their new girls with lit cigarettes or metal brands after encouraging the girls to drink heavily and then stripping them down without their consent. (Robbins 258-259) Any girls who objected to this treatment, however, would be called a bitch and kicked out. Women should not be treating each other this way.It is hard to understand that sororities, which should be lifting their members up, would want to subject their members to even worse treatment than what they already saw at home, in the outside world. They put each other down and are constantly telling them how to do their hair, how to dress, how much to weigh, and how to act. The whole time they are doing this, however, they are telling the new girls that they are not good enough, and probably won't be able to meet those standards. They are told that all of this is to help improve themselves and it's all for the greater good.If a girl decides to stand up for herself, she will have no choice but to leave the sorority for not being able to cut it. Girls that complained were called a bitch and had their rooms ransacked. (Robbins 359) The new girls are told that the sorority is tearing them down in order to build them back up. It destroys their trust in other girls and in a system they thought was going to protect and nurture them. In Born Round, Frank Bruni always had a little trouble with his weight. He came from a big Italian family, where big family dinners and having a lot of food in the house was normal.He had a personal struggle with food. He knew he should not eat so much and dieted f requently because he was embarrassed of his weight. When he got into adulthood, he gained quite a bit of weight at one point. He realized that he was judged, sometimes just by his weight alone. He liked to eat however, and got a job as a food critic. Starting out as a food writer, he managed to keep his weight down to a manageable level. As time went on, however, his weight started to creep back up. When he saw an old family friend while he was heavier, she judged him and told him he was so fat. Bruni, 35)This word. â€Å"fat† sent him into a slight depression, where he put on even more weight. He dieted again, continuing in his circle of up and down weight. It took him a long time to accept who he was and find his healthy weight, and most of his psychological problems with his weight came from the word fat. A single word can be used to belittle, hurt, and humiliate. One word can cause so much hurt that it makes a person doubt who they are and their self worth. It can, howeve r, make a person stronger. It can put events into motion that change a community. One word can change people forever.

From Boom to Bust Financial Crisis of 2008

From Boom to Bust Financial Crisis of 2008 Although academic interest in the global financial crisis that began in the United States in mid-2008 has declined as time goes on, it is a brief period in world economic history that is worth remembering and understanding. Although academic interest in the global financial crisis that began in the United States in mid-2008 has declined as time goes on, it is a brief period in world economic history that is worth remembering and understanding. In many respects, the consequences of the crisis have become a way of life; while the world economy is slowly improving, the financial crisis fundamentally changed many economic relationships between governments, financial institutions, markets, and consumers. From Boom to Bust in Six Easy Steps The chain of events that explains the financial crisis is relatively simple.  Naturally, each of these steps involved a large number of contributing factors. As the US economy improved after the â€Å"dot-com bubble† that created a short-term decline in 1999-2000, much of the recovery was directed into residential construction. In order to generate demand for the huge supply of housing, banks, and lending companies began issuing large numbers of â€Å"adjustable-rate mortgages†, mortgages with a low initial rate and with generally less stringent qualifications for buyers; this allowed a large number of people who had previously not been able to afford their own home a chance to buy one, and in many cases, spend more than was prudent for their level of income. WHAT IS FIAT MONEY The expansion of consumer credit in home loans also led to an increase in credit-funded consumer spending in other parts of the economy as well, fueled in large part through loans against home equity; as long as demand for housing remained strong – which was encouraged by looser credit standards – home prices and property values remained high, and consumers could use that value as collateral for additional spending. Eventually, the housing supply reached a saturation point, which under â€Å"normal† circumstances would have resulted in housing prices declining gradually until a supply-demand equilibrium was reached; this would have been partly achieved by lenders tightening lending standards and incrementally increasing interest rates to compensate for lower revenues. Three things made the situation beginning in late 2005 less than â€Å"normal,† however: The lending business had expanded along with the housing market Because the demand for mortgages was roughly equal to the demand for houses, a large number of lending businesses – most operating under regulatory guidelines that were much less strict than for banks – were started after 2000. The problem this caused was a lack of funding; mortgages take a little time, from the perspective of the lender, to start providing a stable revenue stream that can be used for new loans, unless the lender has a large initial financial reserve, which many did not. That led to the growth of creative funding concepts, such as Mortgage-backed securities, which became a hot market commodity In order to fund the lending boom, large and small lenders alike bundled their outstanding mortgages into financial derivatives called mortgage-backed securities, which took a variety of forms. An MBS is essentially a claim on a percentage of the cash inflow from a mortgage or group of mortgages and is generally paid on a monthly or quarterly basis, similar to a bond coupon. Once an MBS is created, however, its value as a tradable security is not necessarily limited to the expected revenue on paper from the mortgages in the pool; prior to 2008, the market value of these derivatives grew to several trillion dollars, many times the value of the properties they represented. The volatility of these MBS derivatives was a significant trigger for the financial disaster, because MBS were traded worldwide, meaning that US conditions were underliers for the entire global financial system. The drop in home prices, which was an inevitable consequence of a saturated market, led to lower revenues for lenders, which began to reduce the value of MBS’s. This created one self-feeding cycle because it led to less financing for new mortgages; it led to another because the only way the lenders could compensate was to raise the interest – sometimes precipitously – on their adjustable-rate mortgages, which in turn led to an accelerating number of mortgage defaults by borrowers. A mortgage that is not being paid has zero value as part of an MBS; in what seemed to be overnight but in reality was a period from late-2006 to mid-2008, an enormous amount of asset value held by financial institutions in the form of mortgage-backed securities simply vanished. The impact on financial institutions meant that, at a minimum, lending became severely restricted, and a large number of institutions failed outright – 25 in the US in 2008 alone. The evaporation of the credit market impacted business and consumer spending and created the deepest recession in the US since the Great Depression of the 1930’s. Financial institutions overseas were not spared, either; large organizations such as the UK’s Northern Rock, Switzerland’s UBS, and the Royal Bank of Scotland were deeply exposed to the crisis through the MBS trade  and had to resort to various levels of government intervention to prevent utter chaos. The MBS problem affected a large number of investment organizations as well, companies and government bodies who held a large number of derivatives as part of the financial portfolios for pensions and retirement savings for workers. MONEY MAKES THE WORLD GO AROUND The history of the financial crisis is mainly a lesson about the complex – and evidently potentially-risky – connections in global economics. The entire world economy suffered because of an unsustainable condition in the housing market in the US, and the financial products and processes that evolved as a result of that condition. Moves by governments toward better regulation of financial industries, such as the new requirements for financial reserves that will be required under the Third Basel Accord, have largely been aimed at providing firewalls to prevent future financial crises from spreading as far and as fast. In another respect, however, the history of the financial crisis serves as a warning of what can go wrong. In this context, we may find ourselves with some reasons to worry; in some parts of the world such as China and developing Asian countries, rapid expansion of real-estate markets threatens to reach the same â€Å"bubble† levels as what occurred i n the US, and financial markets are beginning to see the reintroduction of exotic derivative securities. Knowing how quickly things can spiral out of control might help to prevent or at least lessen the effects of future financial crises.

Get the Definition of Schwa With Examples in English

Get the Definition of 'Schwa' With Examples in English The term  schwa  (from the Hebrew; pronounced SHWA with alternate spelling shwa) was first used in  linguistics  by the 19th-century German  philologist  Jacob Grimm. The  schwa is the most common vowel sound in English, represented as É™ in the International Phonetic Alphabet. Any vowel letter can stand for the schwa sound. Only words with two or more syllables may have a schwa, which is also called the  mid-central vowel. The schwa represents a mid-central vowel in an unstressed syllable, such as the second syllable in the word woman and the second syllable in the word buses.   Examples and Observations It is extremely important. ... to recognize that pronouncing unstressed vowels as schwa is not lazy or sloppy. All native speakers of Standard English, including the Queen of England, the Prime Minister of Canada, and the President of the United States, use schwa.(Avery, Peter and Susan Ehrlich. Teaching American English Pronunciation, Oxford University Press, 1992.) Reduced Vowels Vowels change in quality when they are reduced. The reduced vowel tends to be not only very short but also very unclear, producing an obscure sound that is hard to identify. Consider, as an example, the name of the California town Orinda, pronounced /É™rin-dÉ™/, with the first vowel and the last vowel reduced to schwa. Only the second vowel in the word, the stressed vowel, maintains its clarity. The other two vowels are very unclear.(Gilbert, Judy B. Clear Speech: Pronunciation and Listening Comprehension in North American English, 3rd ed., Cambridge University Press, 2005.) Dialectal Variations in Schwa Usage If you listen for it, you can hear schwa in all sorts of places where syllables arent stressed- for example, at the beginnings of words like official, occasion, event, and fatigue. Many people... feel that schwa-ful pronunciations are lazy, but really you would sound pretty odd if you did pronounce the full vowel in place of schwa in these words. Pronunciations like ohfficial and ohccasion sound unnatural and rather theatrical. Schwa also occurs in the middle of words like coronation and afterwards. Again, it would be peculiar not to sound schwa in this position- for instance, corohnation for coronation. ... Schwa usage varies greatly between dialects. Australian English speakers often put schwas in places where British and American speakers wont. Striking differences are also now appearing as a consequence of the worldwide spread of English.(Burridge, Kate. Blooming English: Observations on the Roots, Cultivation and Hybrids of the English Language, Cambridge University Press, 2004.) Schwa and Zero Schwa In terms of duration- a phonetic property that the IPA vowel chart does not indicate- schwa is typically quite short, and this short duration may covary with its tendency to be coarticulated. ... [G]iven its short duration and its consequent tendency to camouflage itself to its context through coarticulation, schwa may be confused with its absence, setting up a situation in which schwa-zero alternations may take hold in a system...(Silverman, Daniel. Schwa The Blackwell Companion to Phonology, edited by Marc van Oostendorp et al., Wiley-Blackwell, 2011.) Schwa and English Spelling For the most part, the schwa vowel sound in a two-syllable word is identified by the uh pronunciation and sound. Oftentimes, children spell chocolate as choclat, separate as seprate, or memory as memry. The schwa vowel is thus omitted. The vowel sound schwa is also found in two-syllable words such as alone, pencil, syringe, and taken. Children commonly misrepresent the schwa vowel and spell these words: ulone for alone, pencol for pencil, suringe for syringe, and takin for taken. It is still the vowel in the unstressed syllable that is featured in this case. ... This time, it is substituted with another incorrect vowel. These aforementioned misunderstandings generally disappear as the child advances in his reasoning and knowledge of the English language, learns conventional alternatives for representing sounds, and begins to apply patterning including syllables and a visual sense to his spelling.(Heembrock, Roberta. Why Kids Cant Spell: A Practical Guide to the Missing Component in Language Proficiency, Rowman Littlefield, 2008.) Schwa and the Evolution of Language [T]here is one vowel, now quite common in the languages of the world, that is ... unlikely to have been in the inventories of earliest languages. This is the schwa vowel, [É™], as in the second syllable of English sofa. ... In English, schwa is the classic weak vowel, not used in any crucial contrasting function, but as a variant of (almost) any vowel in unstressed position. ... Not all languages have a schwa vowel, weakening an unstressed vowel as English does. But many languages with similar rhythmic properties to English have an equivalent to the English schwa vowel. It seems likely that the earliest languages, before they had had time to evolve such weakening rules, would not have had a schwa vowel.(Hurford, James R. The Origins of Language, Oxford University Press, 2014.)

Lord of the Manor

Lord of the Manor Lord of the Manor Lord of the Manor By Maeve Maddox A headline at a blog called Hollywood Scoop caught my eye: Scott Disick is Knighted ‘Lord of the Manner’† Thinking that the spelling manner must be a deliberate pun, I read further to see if Disick had received some sort of award having to do with fashion or elegant behavior. Here is the only explanation I found of the â€Å"ceremony† that took place in a London pub: â€Å"I crown you Scott Disick, the new Lord of the Manner,† the ceremony official proclaimed, cloaking Scott in a fur coat and faux crown. I’m guessing that the author of the article, John Howard, may be unfamiliar with the spelling of the expression â€Å"lord of the manor.† A manor is a house on an estate. During feudal times, knights and peasants owed their allegiance to a lord who lived on an estate, in a manor. Ergo, the local master was â€Å"the lord of the manor.† In time, â€Å"lord of the manor† came to refer to any person in authority. In modern usage, it is often used sarcastically to refer to a person who puts on unwarranted airs of self-importance. Here are some examples of the error found in blogs, comments, and ebooks: INCORRECT: Hugh Bonnevi[l]le, who plays the  Lord of the manner, arrived with his wife.- Celebrity blog (UK) CORRECT : Hugh Bonneville, who plays the  lord of the manor, arrived with his wife. INCORRECT: He might be lord of the manner and king of the rainforest, but Sting still has an unerring knack of getting right up people’s noses.- Comment on celebrity site. CORRECT : He might be lord of the manor and king of the rainforest, but Sting still has an unerring knack of getting right up people’s noses. INCORRECT: Lord of the manner  or beggar, we all have intrinsic value.- Self-help blog. CORRECT : Lord of the manor or beggar, we all have intrinsic value. INCORRECT: The lord of the manner, or members of his family, typically manned the courts of feudal Europe.- The Founders Facade: Christianity, Democracy, Freemasonry, and the Founding of America, R. L. Worthy, KornerStone Books, 2004. CORRECT : The lord of the manor, or members of his family, typically manned the courts of feudal Europe. I found several examples of the expression used correctly and incorrectly in the same text, even in the same paragraph, as in this opinion piece on an Australian political blog: In Feudal times free men worked 1 day in six for the lord of the manor (correct), now Rich people work 2.35 days per five day week for the government.  The Socialists say working one day per week for the lord of the manner (incorrect) is slavery, but 2.35 days for the government is totally acceptable as it is for a FAIR society. It’s possible that the error of writing â€Å"lord of the manner† instead of â€Å"lord of the manor† is influenced by the existence of the idiom â€Å"to the manner born.† In fact, â€Å"to the manner born† is often misspelled as â€Å"to the manor born.† Perhaps the most familiar use of the expression â€Å"to the manner born† is the line spoken by Hamlet to Horatio in Act I, scene 4. The friends are on the battlements when they hear the sound of trumpets and gunfire. Startled, Horatio asks what’s going on. Hamlet explains that when King Claudius drinks a toast, the act is signaled with a fanfare and a gunshot. Horatio asks if it’s a Danish custom and Hamlet replies: Ay, marry, is ’t. But to my mind, though I am native here And to the manner born, it is a custom More honored in the breach than the observance. â€Å"To the manner born† means, â€Å"familiar from birth with a given custom.† In modern English, â€Å"to the manner born† is also used to mean â€Å"naturally suited for, or taking readily to, a given role or task.† When using either expression- lord of the manor or to the manner born- be sure to spell it correctly. Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Expressions category, check our popular posts, or choose a related post below:Addressing A Letter to Two PeopleHow to Punctuate Descriptions of ColorsList of 50 Compliments and Nice Things to Say!

Student Voice - Pandora's Box or Philosopher's Stone Essay

Student Voice - Pandora's Box or Philosopher's Stone - Essay Example From this research it is clear that the modern concept of allowing student involvement within the arena of teaching learning is relatively new to UK, though the concept is not new in other parts of the world. Despite the various recent modifications made within UK educational system, it is seen that students are rarely asked to take part, thus remaining largely unheard, during reform processes. To make education more representative, views of the students must be listened to and given its due importance. However, incorporating student’s voice does not merely involve modifying the results of the existing educational systems or locating resolutions to various existing problems. Instead, it deals with modifying processes, methods through which the students can affect the course of education. Here the authors believed that that UK educational system should be so reformed that it would function as per the student’s requirements, instead of the students adjusting themselves to the system. Such radical modifications entail changes at almost all levels, including changes within the basic UK educational culture, and the relationships between students, educationists, and the schools, where there must a disposition on the part of the educationists and policy makers to listen to the students. Students must necessarily be encouraged so that they are become more directly involved in decision-making processes related to their education. The notions of student voice includes various activities that promote discussion, speech, reflection and activities on issues that are related to learners along with its effects on teachers, school staff and the surrounding society. Often this method comprises of methods like peer support, buddying, and other measures that promote and allow the learners to air their opinions and bring about various suitable changes modifications. Such measures include the formation of the creation of school student councils, school boards having s tudents as members, students as members of staff appointment board, researcher-student and the enterprises for ‘child-to-child’ activities that promote leadership amongst the learners, while supporting ‘active citizenship’ through the cooperation of these learners in various community based activities and projects (Futurelab, 2006). In its attempt to bring in students’ voice, the UK Government has mentioned categorically its desire to create a more customised form of an educational system, where the mode of teaching would cater to the needs of the students, and not the other way round. This would be especially helpful for

Interview A Manager Assignment Example | Topics and Well Written Essays - 1500 words

Interview A Manager - Assignment Example In its long journey Coca Cola has done many mergers and acquisitions which have contributed a lot in the growth and development of the company. The firm operates its business through franchise distribution. It only manufactures the syrup and then sent it to various bottling partners. In many places the company itself owns many bottlers. Manager is an important person of an organization. He plays a vital role in planning and directing works to its subordinates. He develops important strategies for growth and development of the company. Under his guidance the company performs vital tasks. The manager has the power to hire and fire employees working under him. He has the authority to judge the performance of its subordinates and give promotion to them. He is the person responsible for administrating and controlling the functions of the organization. A company has different types of manager’s accordi9ng to its divisions. One of the famous managers of Coca Cola is Brandon M. Buchanan. He is with the company for past 17years. For past 1year 3 months he holds the position of District Sales manager of Coca Cola. Brandon M. Buchanan feels pride for working in Coca Cola. In 1996 he joined the company. Now he holds the position of district sales manager. It is a large store in Phoenix, Arizon. As a manager of this store he has to execute sales for generating more revenue. He supervises different promotional activities of the store in Arizon district. It helps to influence the sales figure of that region. He plays a vital role in developing the market for the products of Coca Cola through building community relationship. One of its important job responsibilities is to train and develop its subordinates for achieving the goals and objectives of District Sales Team. He assists its team members in innovating and developing new business plans and opportunities. Brandon M. Buchanan set up and delivers profit and budgeted volume at the

How newspapers will use social media and internet to expand readership Term Paper - 1

How newspapers will use social media and internet to expand readership in the future - Term Paper Example avvy world thus, the social media is strong enough to take over the traditional forms of transmission of news like newspapers, radio, television etc due to faster and better communication among people, rapidity of spread of news, an increase in readership, as well as a growing need to adapt and become environment friendly. Newspapers and radio channels are far behind than television today in terms of the spread of news for the sole reason that with the click of a channel or press of a button one can both see or hear the news on the go, as and when it takes place. Newspapers, even though they provide the audience with a chance to spend time reading and enhancing their knowledge, arrive a day later, by which time the person may already be well versed with the news. Newspapers however have a tangible form that many people are attached to and not willing to give up. Yet, it must be understood that newspapers can make use of the social media in order to expand their readership in the future as more and more people are logged onto the internet these days. Students, workers as well as professionals and home makers – almost everyone and anyone have an account on a social networking website. Thus in order to tap the potential, newspapers can exploit these platforms and display their news banner there, a ttracting readers onto their websites and thus help them in enriching themselves by displaying their news. (Rani Malla) Today, a number of newspapers have online editions, like Wall Street Journal and New York Times to name a few; these newspapers put up everything and more on their online versions, where people may subscribe and get hourly updates on the world’s events. Newspapers can also take over social networking websites to attract more readers by creating their pages and groups and involving forums for communication over the news among various people. Moreover, blogs and online journals are encouraged by newspaper reporters and writers in order to increase

Public Health Law reform Essay Example | Topics and Well Written Essays - 250 words

Public Health Law reform - Essay Example The proposed public laws are crafted to link various three aspects, duty, restraints and power, this are fundamentally missing in the current statutes necessitating the need for the revised form (Novick, Morrow, & Mays, 2008). On duty, the envisaged law compels the government to give priority to the well being of the citizens in promoting dissemination of health services in a non-discriminatory. Interestingly, the state government does not have any affirmative action in the implementation of the policies and this transcends to the judicial systems that lacks clear guidelines on how to apprehend violators of these statutes. These are some of the issues addressed in the new model of the laws. The government should also be given the powers to set the required standards of health and enforce these laws to avoid defaulters getting away with such offences. The regulations in this case rotate on issues like clean water, air and work places to mitigate on the spread of infectious diseases ( Novick, Morrow, & Mays, 2008). The new proposals also endeavor to check on the government involvement in the assessment of these acts such that possible unfair intrusions can be regulated. Even with the drafting of the new reforms, there has been no unanimous public agreement with the reforms and contentious issues are yet to be sort for its implementation (Novick, Morrow, & Mays,

Business Law Essay Example | Topics and Well Written Essays - 1000 words - 30

Business Law - Essay Example C.  Ã‚   With one of the legal issues you identified above, check with a legal web-site, as a reference that gives you greater understanding of this issue, so that you can describe the general rule of law about this issue, and any significant exceptions. As an employee, you have the right to raise a claim of discrimination by the employer only if you belong to a protected class. A protected class implies that you are fully qualified for the job. In such a case, the employer takes negative actions against you particularly by filling your position with an unqualified employee who does not fit in the protected class. If you want to raise the claim, you must either have circumstantial or direct evidence. The book serves as a special dedication to employees and employers. It provides guidance and information regarding legal employment issues. The workplace laws enacted by the state legislatures, congress, and local government meant to bring just for both parties. The book also highlights a case law that pertains to decisions made on precedent cases. Other critical issues addressed in the books are such as employment contract, company’s personnel, collective-bargaining agreement, and civil service rules. The book also focuses on federal laws and, in particular, the different kinds of employment laws. In the first category, the book addresses the anti-discrimination legislation. According to the Civil Rights Act of 1964 title VII, employment discrimination based on religion, color, pregnancy, race, sex and national origin is prohibited. The Rehabilitation Act of the Americans with Disabilities Act (ADA) prohibits employment discrimination against people living with disabilities. The Age Discrimination Employment Act (ADEA) forbids employment discrimination based on age. Discrimination against persons aged 40 and above is an offense. Another category addressed by the book relates to salaries and hours of work. The Fair Labor Standards Act

Social Therapeutic Work Practices Article Example | Topics and Well Written Essays - 750 words

Social Therapeutic Work Practices - Article Example The therapist will have to extend his assessment to describe the client’s inherent reaction to environmental and social conditions that frequently spark violent responses. Therapists dealing with African American youths should transform some of the symbols and rites used in clandestine and corrupt ways into Microsystems that instill therapeutic change. Urban adolescents that engage in illegal behaviors value the symbols and ceremonies since they induce a sense of security and support (Toldson & Toldson, 1999, p. 77). The symbols and rites can thus be helpful in showing clients that they will still benefit when they change. It is also important to use the African-centered instructional material. The therapists should thus establish secret codes, phrases, symbols, and rites of passage that closely resemble those of West Africa. The incorporation of these elements will help the clients to appreciate greatly and understand group processes and improve the compatibility of the processes with African ethos. Dealing with Africa American clients requires prompting of initiative behaviors within the group. As such, therapists should interweave typical therapeutic factors (such as the installation of universality, hope, imparting information, and altruism) with esoteric group therapy. The process of attaining the factors within some cultural groups should involve cultural awareness. When working with clients from an individual culture, group therapy alone will not be enough. It is important to incorporate the traditional group therapy with conceptions and perspectives from that particular culture.

Business Law Essay Example | Topics and Well Written Essays - 1000 words - 30

Business Law - Essay Example C.  Ã‚   With one of the legal issues you identified above, check with a legal web-site, as a reference that gives you greater understanding of this issue, so that you can describe the general rule of law about this issue, and any significant exceptions. As an employee, you have the right to raise a claim of discrimination by the employer only if you belong to a protected class. A protected class implies that you are fully qualified for the job. In such a case, the employer takes negative actions against you particularly by filling your position with an unqualified employee who does not fit in the protected class. If you want to raise the claim, you must either have circumstantial or direct evidence. The book serves as a special dedication to employees and employers. It provides guidance and information regarding legal employment issues. The workplace laws enacted by the state legislatures, congress, and local government meant to bring just for both parties. The book also highlights a case law that pertains to decisions made on precedent cases. Other critical issues addressed in the books are such as employment contract, company’s personnel, collective-bargaining agreement, and civil service rules. The book also focuses on federal laws and, in particular, the different kinds of employment laws. In the first category, the book addresses the anti-discrimination legislation. According to the Civil Rights Act of 1964 title VII, employment discrimination based on religion, color, pregnancy, race, sex and national origin is prohibited. The Rehabilitation Act of the Americans with Disabilities Act (ADA) prohibits employment discrimination against people living with disabilities. The Age Discrimination Employment Act (ADEA) forbids employment discrimination based on age. Discrimination against persons aged 40 and above is an offense. Another category addressed by the book relates to salaries and hours of work. The Fair Labor Standards Act

Poverty in Canada Essay Example for Free

Poverty in Canada Essay Poverty in Canada has been a long debate on the political and social fronts of the community. According to 2005 reports, an estimated over ten percent of the Canada population are living in poverty. Of much concern is the ever increasing rate of homelessness experienced in the nation over the past two decades (Lee, 2000). However, numerous reports have indicated that the measure of poverty in Canada is negated by the government’s failure to have a definite method of measuring poverty levels. True to the letter, Canadians are current faced with the debate on whether absolute or relative measure of poverty is the best in determining poverty levels in the nation. Nevertheless, numerous measures have been put in place to promote poverty reduction strategies in many provinces of Canada. In addition, non-governmental organizations are increasingly engaging in community based poverty reduction projects. This paper is written as a discussion on poverty in Canada. The author will in particular look at the statistics of poverty in the nation, how poverty is measured in Canada, and the current poverty reduction measures being implemented. Poverty in Canada Poverty in Canada has been an historical issue for many centuries. According to available statistical information, poverty in the nation remains a swing between economic growth and recession as well as numerous evolving initiatives by the government to assist low income members of the community (Raphael, 2002). This information still indicates the emergence of organized assistance to the poor in the twentieth century. True to available literature, most of the poor assistance programs are generally funded by the church. This is evident from the catholic encyclopedia, which funds approximated over eighty seven hospitals in the Canadian nation catering for the poor members of the community (Surhone, 2009). On the other hand, the government has been on the forefront in addressing poverty issues among its citizens. Such can be historically evident from the establishment of the Canada’s welfare state after the great depression as was initiated by Bennett and Mackenzie King. Nevertheless, the problem of poverty in Canada is still a major threat to the sustainable social and economic development of the Canadians. From a 2003 statistical reports, an estimated poverty rate of over 10% has been reported (Raphael, 2002). This percentage has been confirmed by the central intelligence agency as an official value although the absolute rate is undoubtedly expected to be higher. However, the Canadian federal government seems not to agree with this value and have published a current poverty rate to have gone down for the past sixty years to a value less than five percent (Raphael, 2002). This value was determined on the basis of the basic needs poverty measure and deviates very much from what is perceived to be real. Many organizations top on the list being the Fraser institute have not appreciated this value and depict the Canadian federal government as extremely exaggerative. The above contradiction between the government and these conservative organizations has been compounded by the fact that the Canadian federal government has failed to endorse any metric measure of poverty including but not limited to the low income cut off. Altogether, the Canadian federal government seems to have realized the impact of poverty to the society and have employed several measures to reduce it. This is evidenced by the continued decline of poverty in the recent time 1996 when recession which was marked with low income rates. For instance, statistics shows that the less fortunate people such as the physically disabled, mentally ill, and single parent mothers are experiencing higher income rates. Students and recent immigrants have at least higher or average low income rate hence they can afford the basic needs. Measures of poverty in Canada The establishment of an official poverty measuring system in America has been marked with many controversies top on the list being the fact that politicians have failed to agree on a precise definition of poverty (Groot-Maggett, 2002). The have therefore ignored the interest of statistics Canada of defining poverty by it unable and unworthy to determine what is necessary to be a basic necessity. The government and some research institutes use different methods to estimate the extent of poverty of poverty in Canada. However, a debate has emerged on the supremacy of absolute and relative methods of measuring the depth of poverty. The author of this paper discuses both the absolute and the relative measures of poverty. One of the absolute measures of poverty is the basic needs poverty measure. According to libertarian Fraser institute’s economist Chris sarlo, the basic needs poverty measure was conceived to be a poverty threshold (Groot-Maggett, 2002). According to this basic needs approach of poverty, basic needs are those things which are required by people for their physical goods over a long time depending on the current living standards of that particular society. This measure was designed based on different information obtained fro various sources which include but not limited to statistics Canada. An extensive assessment of how much a person can spend in the house was established to give this measure the originality and substance it deserves. This was accomplished by examining the cost of various things which where perceived to meet the above definition of basic need. This included food, clothing, shelter, personal care, transport and communication for different types of societies. Based on the above research and by putting inconsideration the family size, the number of families which had insufficient income to cater for those necessities were determined. Earlier on, the amount of income required to cater for the basic necessities was determined on the basis of gross income which was inclusive of old age pensions and employment insurances. Currently however, the net income has been used the financial ability of a family to sustain its basic requirements (Lee, 2000). A worthy noting point is that this net income is based on reports which can be marked with error such as unreported and underground means of earning income. Based on the basic needs poverty measure, have gone down with an appreciatable rate to a value less than 5% which is estimated to represent less than 2million Canadians. Another absolute measure of poverty is termed the market basket measure. This was designed and established in 2003 by the Canadian government through its department of human resources and skills development (Raphael, 2002). The market basket measure of poverty accommodated a wider range of basic needs than the basic need measure. For instance, it put in consideration the community size and location for at least 48 communities in Canadians and then estimated the sufficient amount of income required to meet those needs. This measure is still understudy and is expected to cover more than 400 communities. The main notable relative property measures is the income distribution measure commonly known as income inequality metrics, gives information regarding the variation of income in a given community. Its effectiveness is evidenced by the fact that when a given group of people increases their income rate then there is a high probability of those earning less to feel an increase in their income. Another often quoted as a relative measure of poverty is the low income cut off which has received many critics from the statistics Canada and they have disregarded it as not a measure of poverty by saying that it does not give reliable and accurate fingers. The low income cut off measure was based on the gross income but the statistics Canada have given reports of both the gross and the net income (Marseken, Timpledon, Surhone, 2009). This measure was designed to give the lowest mark which when exceeded; a family will have to spend much to cater for basic needs such as food shelter and clothing. Recent results based on this measure showed that approximate of 9. 4% lives below the low the current threshold of 63% of the total family income. Poverty reduction measures Like any other country in the world which is conscious of the well being of its people, the Canadian government through the provinces has employed several measures to eliminate poverty and a gain to reduce its impact to the people. Top on the list of these important measures is reduction of tax burdens. This is evidenced by the progressive income tax system in Canada which has resulted to a difference of about 5% between the gross and net low income cut off (Pohl, 2002). Government social programs cannot go unmentioned here because of their importance and effectiveness in succumbing poverty. The Canadian government has come up with a broad range of social programs aimed at helping the law income people. These programs include but not limited to old age security and employment insurance which have seen through the reduction of chances of falling to poverty of people who were rendered unemployed. In addition to this, government funds have been channeled to subsidizing education and public health with an aim of improving the living standards of people with low income (Raphael, 2002). Another government measure which cannot escape this discussion is the introduction of the minimum wage laws. The constitution of Canada includes the minimum wage laws, which even though they vary for different provinces, they have confirmed there effectiveness in standardizing wages by making sure that people with law income are not exploited (Raphael, 2002). The minimum set minimum wage is $8. 00 per hour although it can go a bit down for unskilled workers. Conclusion In conclusion therefore, poverty is not well defined in Canada because of the failure of politicians to agree on the necessities which should be basic. However, the above discussion shows that a considerable number of people in Canada are poor and lacks the basic needs a defined by the basic needs measure of poverty. In addition to this, the government’s effort to eliminate poverty as well as reducing its impacts cannot fail to be appreciated. This is it has invested sufficiently in social programs and in the enforcement of the minimum law wages which have seen through the reduction of poverty and its effect to the people. It also safeguard the less fortunate people and ensured that the poor people are not exploited or robed there right of living a good life. References Groot-Maggetti, G. (2002). A measure if Poverty in Canada. A Guide to the Debate about Poverty. Retrieved August 1, 2010, from http://action. web. ca/home/cpj/attach/A_measure_of_poverty. pdf Lee, K. (2000). Urban Poverty in Canada: Statistical Profile. Retrieved August 2, 2010, from http://www.ccsd. ca/pubs/2000/up/ Marseken, S. , Timpledon, M. , Surhone, L. (2009). Poverty in Canada: Poverty, Minimum Wage, Measuring Poverty, Income Taxes in Canada, Economic History of Canada, Great Depression in Canada, Basic Needs, Economic Inequality. Toronto: Betascript Publishers. Pohl, R. (2002). Poverty in Canada. Retrieved August 1, 2010, from http://www. streetlevelconsulting. ca/homepage/homelessness2InCanada_Part2. htm Raphael, D. (2002). Poverty, Income Inequality, and Health in Canada. Retrieved August 2, 2010, from http://www. povertyandhumanrights. org/docs/incomeHealth. pdf

High Performance Wireless Telecommunications Modulation

High Performance Wireless Telecommunications Modulation Introduction The primary goal of the project is to analyze of OFDM system and to assess the suitability of OFDM as a modulation technique for wireless communications. In the part of project is covered two leading successfully implementation of OFDM based technologies are Digital Video Broadcasting (DVB-T and DVB-H) and Long Term Evolution (LTE advanced for 4G). Wireless communications is an emerging field, which has seen enormous growth in the last several years. The huge uptake rate of mobile phone technology, Wireless Local Area Networks (WLAN) and the exponential growth of the Internet have resulted in an increased demand for new methods of obtaining high capacity wireless networks. For cellular mobile applications, we will see in the near future a complete convergence of mobile phone technology, computing, Internet access, and potentially many multimedia applications such as video and high quality audio. In fact, some may argue that this convergence has already largely occurred, with the advent of being able to send and receive data using a notebook computer and a mobile phone. The goal of third and fourth generation mobile networks is to provide users with a high data rate, and to provide a wider range of services, such as voice communications, videophones, and high speed Internet access. The higher data rate of future mobile networks will be achieved by increasing the amount of spectrum allocated to the service and by improvements in the spectral efficiency. OFDM is a potential candidate for the physical layer of fourth generation mobile systems. Basic Principles of OFDM OFDM overview The Orthogonal Frequency Division Multiplexing (OFDM) is a modulation technique where multiple low data rate carriers are combined by a transmitter to form a composite high data rate transmission. The first commercial use of OFDM in the communication field was in the 1980s, and it was later widely used in the broadcast audio and video field in the 1990s in such areas as, ADSL, VHDSL, ETSI standard digital audio broadcast (DAB), digital video broadcast (DVB), and high-definition digital TV (HDTV). Digital signal processing makes OFDM possible. To implement the multiple carrier scheme using a bank of parallel modulators would not be very efficient in analog hardware. However, in the digital domain, multi-carrier modulation can be done efficiently with currently available DSP hardware and software. Not only can it be done, but it can also be made very flexible and programmable. This allows OFDM to make maximum use of available bandwidth and to be able to adapt to changing system requirements. Figure 1 is illustrated, Instead of separate modulators; the outgoing waveform is created by executing a high-speed inverse DFT on a set of time-samples of the transmitted data (post modulation). The output of the DFT can be directly modulated onto the outgoing carrier, without requiring any other components. Each carrier in an OFDM system is a sinusoid with a frequency that is an integer multiple of a base or fundamental sinusoid frequency. Therefore, each carrier is like a Fourier series component of the composite signal. In fact, it will be shown later that an OFDM signal is created in the frequency domain, and then transformed into the time domain via the Discrete Fourier Transform (DFT). Two periodic signals are orthogonal when the integral of their product, over one period, is equal to zero. This is true of certain sinusoids as illustrated in Equation 1. Definition of Orthogonal The carriers of an OFDM system are sinusoids that meet this requirement because each one is a multiple of a fundamental frequency. Each one has an integer number of cycles in the fundamental period. [2, 145-153; 6] The importantance of being orthogonal The main concept in OFDM is orthogonality of the sub-carriers.Since the carriers are all sine/cosine wave, we know that area under one period of a sine or a cosine wave is zero. Lets take a sine wave of frequency m and multiply it by a sinusoid (sine or a cosine) of a frequency n, where both m and n are integers. The integral or the area under this product is given by These two components are each a sinusoid, so the integral is equal to zero over one period. When we multiply a sinusoid of frequency n by a sinusoid of frequency m/n the area under the product is zero. In general for all integers n and m , sin(mx), cos(mx), cos(nx) , sin(nx) are all orthogonal to each other. These frequencies are called harmonics. Making the subcarriers mathematically orthogonal was a breakthrough for OFDM because it enables OFDM receivers to separate the subcarriers via an FFT and eliminate the guard bands. As figure 3 shows, OFDM subcarriers can overlap to make full use of the spectrum, but at the peak of each subcarrier spectrum, the power in all the other subcarriers is zero. OFDM therefore offers higher data capacity in a given spectrum while allowing a simpler system design. Creating orthogonal subcarriers in the transmitter is easy using an inverse FFT. To ensure that this orthogonality is maintained at the receiver (so that the subcarriers are not misaligned), the system must keep the transmitter and receiver clocks closely synchronizedwithin 2 parts per million in 802.11a systems. The 802.11a standard therefore dedicates four of its 52 subcarriers as pilots that enable phase-lock loops in the receiver to track the phase and frequency of the incoming signal. The 802.11a standard therefore dedicates four of its 52 subcarriers as pilots that enable phase-lock loops in the receiver to track the phase and frequency of the incoming signal. This method also eliminates low-frequency phase noise.Separating the subcarriers via an FFT require about an order of magnitude fewer multiply-accumulate operations than individually filtering each carrier. In general, an FFT implementation is much simpler than the RAKE receivers used for CDMA and the decision-feedback equalizers for TDMA.This idea are key to understanding OFDM. The orthogonality allows simultaneously transmission on a lot of sub- carriers in a tight frequency space without interference form each other. In essence this is similar to CDMA, where codes are used to make data sequences independent (also orthogonal) which allows many independent users to transmitin same space successfully.[2, 153-154; 6 ; 7] OFDM Operation Preliminary Concepts When the DFT (Discrete Fourier Transform) of a time signal is taken, the frequency domain results are a function of the time sampling period and the number of samples as shown in Figure 4. The fundamental frequency of the DFT is equal to 1/NT (1/total sample time). Each frequency represented in the DFT is an integer multiple of the fundamental frequency. Parameter Mapping from Time to Frequency for the DFT The maximum frequency that can be represented by a time signal sampled at rate 1/T is fmax = 1/2T as given by the Nyquist sampling theorem. This frequency is located in the center of the DFT points. All frequencies beyond that point are images of the representative frequencies. The maximum frequency bin of the DFT is equal to the sampling frequency (1/T) minus one fundamental (1/NT).The IDFT (Inverse Discrete Fourier Transform) performs the opposite operation to the DFT. It takes a signal defined by frequency components and converts them to a time signal. The parameter mapping is the same as for the DFT. The time duration of the IDFT time signal is equal to the number of DFT bins (N) times the sampling period (T).It is perfectly valid to generate a signal in the frequency domain, and convert it to a time domain equivalent for practical use (The frequency domain is a mathematical tool used for analysis. Anything usable by the real world must be converted into a real, time domain signal). This is how modulation is applied in OFDM. In practice the Fast Fourier Transform (FFT) and IFFT are used in place of the DFT and IDFT, so all further references will be to FFT and IFFT.[1 ,118 ; 4] Definition of Carriers The maximum number of carriers used by OFDM is limited by the size of the IFFT. This is determined as follows in Equation 2. OFDM Carrier Count In order to generate a real-valued time signal, OFDM (frequency) carriers must be defined in complex conjugate pairs, which are symmetric about the Nyquist frequency (fmax). This puts the number of potential carriers equal to the IFFT size/2. The Nyquist frequency is the symmetry point, so it cannot be part of a complex conjugate pair. The DC component also has no complex conjugate. These two points cannot be used as carriers so they are subtracted from the total available. If the carriers are not defined in conjugate pairs, then the IFFT will result in a time domain signal that has imaginary components. This must be a viable option as there are OFDM systems defined with carrier counts that exceed the limit for real-valued time signals given in Equation 2.In general, a system with IFFT size 256 and carrier count 216. This design must result in a complex time waveform. Further processing would require some sort of quadrature technique (use of parallel sine and cosine processing paths). In this report, only real-value time signals will be treated, but in order to obtain maximum bandwidth efficiency from OFDM, the complex time signal may be preferred (possibly an analogous situation to QPSK vs. BPSK). Equation 2, for the complex time waveform, has all IFFT bins available as carriers except the DC bin. Both IFFT size and assignment (selection) of carriers can be dynamic. The transmitter and receiver just have to use the same parameters. This is one of the advantages of OFDM. Its bandwidth usage (and bit rate) can be varied according to varying user requirements. A simple control message from a base station can change a mobile units IFFT size and carrier selection.[2,199-206; 4] Modulation Binary data from a memory device or from a digital processing stream is used as the modulating (baseband) signal. The following steps may be carried out in order to apply modulation to the carriers in OFDM: combine the binary data into symbols according to the number of bits/symbol selected convert the serial symbol stream into parallel segments according to the number of carriers, and form carrier symbol sequences apply differential coding to each carrier symbol sequence convert each symbol into a complex phase representation assign each carrier sequence to the appropriate IFFT bin, including the complex conjugates take the IFFT of the result OFDM modulation is applied in the frequency domain. Figure 5 and Figure 6 give an example of modulated OFDM carriers for one symbol period, prior to IFFT. OFDM Carrier Magnitude prior to IFFT For this example, there are 4 carriers, the IFFT bin size is 64, and there is only 1 bit per symbol. The magnitude of each carrier is 1, but it could be scaled to any value. The phase for each carrier is either 0 or 180 degrees, according to the symbol being sent. The phase determines the value of the symbol (binary in this case, either a 1 or a 0). In the example, the first 3 bits (the first 3 carriers) are 0, and the 4th bit (4th carrier) is a 1. OFDM Carrier Phase prior to IFFT Note that the modulated OFDM signal is nothing more than a group of delta (impulse) functions, each with a phase determined by the modulating symbol. In addition, note that the frequency separation between each delta is proportional to 1/N where N is the number of IFFT bins. The frequency domain representation of the OFDM is described in Equation 3. OFDM Frequency Domain Representation (one symbol period) After the modulation is applied, an IFFT is performed to generate one symbol period in the time domain. The IFFT result is shown in 7. It is clear that the OFDM signal has varying amplitude. It is very important that the amplitude variations be kept intact as they define the content of the signal. If the amplitude is clipped or modified, then an FFT of the signal would no longer result in the original frequency characteristics, and the modulation may be lost. This is one of the drawbacks of OFDM, the fact that it requires linear amplification. In addition, very large amplitude peaks may occur depending on how the sinusoids line up, so the peak-to-average power ratio is high. This means that the linear amplifier has to have a large dynamic range to avoid distorting the peaks. The result is a linear amplifier with a constant, high bias current resulting in very poor power efficiency. OFDM Signal, 1 Symbol Period Figure 8 is provided to illustrate the time components of the OFDM signal. The IFFT transforms each complex conjugate pair of delta functions (each carrier) into a real-valued, pure sinusoid. Figure 8 shows the separate sinusoids that make up the composite OFDM waveform given in Figure 7. The one sinusoid with 180 phase shift is clearly visible as is the frequency difference between each of the 4 sinusoids. Transmission The key to the uniqueness and desirability of OFDM is the relationship between the carrier frequencies and the symbol rate. Each carrier frequency is separated by a multiple of 1/NT (Hz). The symbol rate (R) for each carrier is 1/NT (symbols/sec). The effect of the symbol rate on each OFDM carrier is to add a sin(x)/x shape to each carriers spectrum. The nulls of the sin(x)/x (for each carrier) are at integer multiples of 1/NT. The peak (for each carrier) is at the carrier frequency k/NT. Therefore, each carrier frequency is located at the nulls for all the other carriers. This means that none of the carriers will interfere with each other during transmission, although their spectrums overlap. The ability to space carriers so closely together is very bandwidth efficient. OFDM Time Waveform Figure 9 shows the OFDM time waveform for the same signal. There are 100 symbol periods in the signal. Each symbol period is 64 samples long (100 x 64 = 6400 total samples). Each symbol period contains 4 carriers each of which carries 1 symbol. Each symbol carries 1 bit. Note that Figure 9 again illustrates the large dynamic range of the OFDM waveform envelope. OFDM Spectrum Figure 10 shows the spectrum for of an OFDM signal with the following characteristics: 1 bit / symbol 100 symbols / carrier (i.e. a sequence of 100 symbol periods) 4 carriers 64 IFFT bins spectrum averaged for every 20 symbols (100/20 = 5 averages) Red diamonds mark all of the available carrier frequencies. Note that the nulls of the spectrums line up with the unused frequencies. The four active carriers each have peaks at carrier frequencies. It is clear that the active carriers have nulls in their spectrums at each of the unused frequencies (otherwise, the nulls would not exist). Although it cannot be seen in the figure, the active frequencies also have spectral nulls at the adjacent active frequencies. It is not currently practical to generate the OFDM signal directly at RF rates, so it must be up converted for transmission. To remain in the discrete domain, the OFDM could be upsampled and added to a discrete carrier frequency. This carrier could be an intermediate frequency whose sample rate is handled by current technology. It could then be converted to analog and increased to the final transmit frequency using analog frequency conversion methods. Alternatively, the OFDM modulation could be immediately converted to analog and directly increased to the desired RF transmits frequency. Either way, the selected technique would have to involve some form of linear AM (possibly implemented with a mixer). [1, 122-125; 6] Reception and Demodulation The received OFDM signal is down converted (in frequency) and taken from analog to digital. Demodulation is done in the frequency domain (just as modulation was). The following steps may be taken to demodulate the OFDM: partition the input stream into vectors representing each symbol period take the FFT of each symbol period vector extract the carrier FFT bins and calculate the phase of each calculate the phase difference, from one symbol period to the next, for each carrier decode each phase into binary data sort the data into the appropriate order OFDM Carrier Magnitude following FFT Figure 11 and Figure 12 show the magnitude and spectrum of the FFT for one received OFDM symbol period. For this example, there are 4 carriers, the IFFT bin size is 64, there is 1 bit per symbol, and the signal was sent through a channel with AWGN having an SNR of 8 dB. The figures show that, under these conditions, the modulated symbols are very easy to recover. OFDM Carrier Phase following FFT In Figure 12 that the unused frequency bins contain widely varying phase values. These bins are not decoded, so it does not matter, but the result is of interest. Even if the noise is removed from the channel, these phase variations still occur. It must be a result of the IFFT/FFT operations generating very small complex values (very close to 0) for the unused carriers. The phases are a result of these values. [1, 125 -128; 3] OFDM transceiver OFDM signals are typically generated digitally due to the difficulty in creating large banks of phase lock oscillators and receivers in the analog domain. Figure 13 shows the block diagram of a typical OFDM transceiver. The transmitter section converts digital data to be transmitted, into a mapping of subcarrier amplitude and phase. It then transforms this spectral representation of the data into the time domain using an Inverse Discrete Fourier Transform (IDFT). The Inverse Fast Fourier Transform (IFFT) performs the same operations as an IDFT, except that it is much more computationally efficiency, and so is used in all practical systems. In order to transmit the OFDM signal the calculated time domain signal is then mixed up to the required frequency. Block diagram showing a basic OFDM transceiver [3] The receiver performs the reverse operation of the transmitter, mixing the RF signal to base band for processing, then using a Fast Fourier Transform (FFT) to analyze the signal in the frequency domain. The amplitude and phase of the subcarriers is then picked out and converted back to digital data. The IFFT and the FFT are complementary function and the most appropriate term depends on whether the signal is being received or generated. In cases where the Signal is independent of this distinction then the term FFT and IFFT is used interchangeably. [1, 125 -128, 3] Analysis of OFDM characteristics Guard Period OFDM demodulation must be synchronized with the start and end of the transmitted symbol period. If it is not, then ISI will occur (since information will be decoded and combined for 2 adjacent symbol periods). ICI will also occur because orthogonality will be lost (integrals of the carrier products will no longer be zero over the integration period), To help solve this problem, a guard interval is added to each OFDM symbol period. The first thought of how to do this might be to simply make the symbol period longer, so that the demodulator does not have to be so precise in picking the period beginning and end, and decoding is always done inside a single period. This would fix the ISI problem, but not the ICI problem. If a complete period is not integrated (via FFT), orthogonality will be lost. The effect of ISI on an OFDM signal can be further improved by the addition of a guard period to the start of each symbol. This guard period is a cyclic copy that extends the length of the symbol waveform. Each subcarrier, in the data section of the symbol, (i.e. the OFDM symbol with no guard period added, which is equal to the length of the IFFT size used to generate the signal) has an integer number of cycles. Because of this, placing copies of the symbol end-to-end results in a continuous signal, with no discontinuities at the joins. Thus by copying the end of a symbol and appending this to the start results in a longer symbol time. Addition of a guard period to an OFDM signal [3] In Figure 14, The total length of the symbol is Ts=TG + TFFT, where Ts is the total length of the symbol in samples, TG is the length of the guard period in samples, and TFFT is the size of the IFFT used to generate the OFDM signal. In addition to protecting the OFDM from ISI, the guard period also provides protection against time-offset errors in the receiver. For an OFDM system that has the same sample rate for both the transmitter and receiver, it must use the same FFT size at both the receiver and transmitted signal in order to maintain subcarrier orthogonality. Each received symbol has TG + TFFT samples due to the added guard period. The receiver only needs TFFT samples of the received symbol to decode the signal. The remaining TG samples are redundant and are not needed. For an ideal channel with no delay spread the receiver can pick any time offset, up to the length of the guard period, and still get the correct number of samples, without crossing a symbol boundary. Function of the guard period for protecting against ISI [3] Figure 15 shows this effect. Adding a guard period allows time for the transient part of the signal to decay, so that the FFT is taken from a steady state portion of the symbol. This eliminates the effect of ISI provided that the guard period is longer than the delay spread of the radio channel. The remaining effects caused by the multipath, such as amplitude scaling and phase rotation are corrected for by channel equalization. In order to avoid ISI and ICI, the guard period must be formed by a cyclic extension of the symbol period. This is done by taking symbol period samples from the end of the period and appending them to the front of the period. The concept of being able to do this, and what it means, comes from the nature of the IFFT/FFT process. When the IFFT is taken for a symbol period (during OFDM modulation), the resulting time sample sequence is technically periodic. This is because the IFFT/FFT is an extension of the Fourier Transform which is an extension of the Fourier Series for periodic waveforms. All of these transforms operate on signals with either real or manufactured periodicity. For the IFFT/FFT, the period is the number of samples used. Guard Period via Cyclic Extension With the cyclic extension, the symbol period is longer, but it represents the exact same frequency spectrum. As long as the correct number of samples are taken for the decode, they may be taken anywhere within the extended symbol. Since a complete period is integrated, orthogonality is maintained. Therefore, both ISI and ICI are eliminated. Note that some bandwidth efficiency is lost with the addition of the guard period (symbol period is increased and symbol rate is decreased) [2,154-160, 3] Windowing The OFDM signal is made up of a series of IFFTs that are concatenated to each other. At each symbol period boundary, there is a signal discontinuity due to the differences between the end of one period and the start of the next. These discontinuities can cause high frequency spectral noise to be generated (because they look like very fast transitions of the time waveform). To avoid this, a window function (Hamming, Hanning, Blackman, ) may be applied to each symbol period. The window function would attenuate the time waveform at the start and the end of each period, so that the discontinuities are smaller, and the high frequency noise is reduced. However, this attenuation distorts the signal and some of the desired frequency content is lost.[1, 121;2 154] Multipath Characteristics OFDM avoids frequency selective fading and ISI by providing relatively long symbol periods for a given data rate. This is illustrated in Figure 17. For a given transmission channel and a given source data rate, OFDM can provide better multipath characteristics than a single carrier. OFDM vs. Single Carrier, Multipath Characteristic Comparison However, since the OFDM carriers are spread over a frequency range, there still may be some frequency selective attenuation on a time-varying basis. A deep fade on a particular frequency may cause the loss of data on that frequency for a given time, but the use of Forward Error Coding can fix it. If a single carrier experienced a deep fade, too many consecutive symbols may be lost and correction coding may be ineffective. [8] Bandwidth A comparison of RF transmits bandwidth between OFDM and a single carrier is shown in Figure 18 (using the same example parameters as in Figure 17). OFDM Bandwidth Efficiency In Figure 18, the calculations show that OFDM is more bandwidth efficient than a single carrier. Note that another efficient aspect of OFDM is that a single transmitters bandwidth can be increased incrementally by addition of more adjacent carriers. In addition, no bandwidth buffers are needed between transmit bandwidths of separate transmitters as long as orthogonality can be maintained between all the carriers.[2, 161-163; 8; 9] Physical Implementation Since OFDM is carried out in the digital domain, there are many ways it can be implemented. Some options are provided in the following list. Each of these options should be viable given current technology: ASIC (Application Specific Integrated Circuit) ASICs are the fastest, smallest, and lowest power way to implement OFDM Cannot change the ASIC after it is built without designing a new chip General-purpose Microprocessor or MicroController PowerPC 7400 or other processor capable of fast vector operations Highly programmable Needs memory and other peripheral chips Uses the most power and space, and would be the slowest Field-Programmable Gate Array (FPGA) An FPGA combines the speed, power, and density attributes of an ASIC with the programmability of a general purpose processor. An FPGA could be reprogrammed for new functions by a base station to meet future (currently unknown requirements).This should be the best choice.[9] OFDM uses in DVB (Digital Video Broadcasting) DVB (Digital Video Broadcast) is a set of standards for the digital transmission of video and audio streams, and also data transmission. The DVB standards are maintained by the DVB Project, which is an industry-led consortium of over 260 broadcasters, manufacturers, network operators, software developers, regulatory bodies and others in over 35 countries. DVB has been implemented over satellite (DVB-S, DVB-S2), cable (DVB-C), terrestrial broadcasting (DVB-T), and handheld terminals (DVB-H). the DVB standard following the logical progression of signal processing steps, as well as source and channel coding, COFDM modulation, MPEG compression and multiplexing methods, conditional access and set-top box Technology. In this project is presented an investigation of two OFDM based DVB standards, DVB-T and DVB-H. DVB-T (Digital Video Broadcasting Terrestrial) The first Terrestrial Digital Video Broadcasting pilot transmissions were started in the late 90s, and the first commercial system was established in Great Britain. In the next few years the digital broadcasting system has been set up in many countries, and the boom of the digital terrestrial transmission is estimated in the next few years, while the analogue transmission will be cancelled within about 15 years. The greatest advantage of the digital system is the effective use of the frequency spectrum and its lower radiated power in comparison with the analogue transmission, while the covered area remains the same. Another key feature is the possibility of designing a so-called Single Frequency Network (SFN), which means that the neighboring broadcast stations use the same frequency and the adjacent signals dont get interfered. The digital system transmits a data stream, which means that not only television signals but data communication (e.g. Internet service) may be used according to the demands. The data stream consists of an MPEG-2 bit stream, which means a compression is used, enabling the transfer of even 4 or 5 television via the standard 8 MHz wide TV channel. For the viewer, the main advantages are the perfect, noise-free picture, CD quality sound, and easier handling, as well as services like Super Teletext, Electronic Programme Guide, interactivity and mobility.[11, 251-253] Modulation technique in DVB-T The DVB-T Orthogonal Frequency Division Multiplexing (OFDM) modulation system uses multi-carrier transmission. There are 2 modes, the so-called 2k and 8k modes, using 1705 and 6817 carriers respectively, with each carrier modulated separately and transmitted in the 8 MHz TV channel. The common modulation for the carriers is typically QPSK, 16-QAM or 64-QAM. Each signal can be divided into two, so-called „In Phase (I) and „Quadrature Phase components, being a 90Â ° phase shift between them. The constellation diagram and the bit allocation is shown in bellow 16-QAM constellation diagram and bit allocation [6] This modulation can be demonstrated in the constellation diagram, where the 2 axes represent the 2 components (I and Q). In case of using 16-QAM modulation, the number of states is 16, so 1 symbol represents 4 bits. [11, 255; 6; 14] Bir errors If we simulate all the carriers in the constellation diagram we get not just 1 discrete point, but many points, forming a „cloud and representing each state. In case of additive noise the „cloud gets bigger and the receiver may decide incorrectly, resulting in bit errors. Figure 2 shows the measured constellation diagram without and with additive noise. Measured 16-QAM constellation diagram a) without additive noise b) with additive noise [6] To ensure perfect picture quality, the DVB-T system uses a 2 level error correction (Reed-Solomon and Viterbi). This corrects the bad bits at an even 10-4 Bit Error Rate (BER) and enables error-free data transmission. [13, 32-36] The multi-carrier structure The structure of carriers can be illustrated also in the function of time (Figure 20). The horizontal axis is the frequency and the vertical axis is the time. The 8 MHz channel consists of many carriers, placed 4462 Hz or 1116 Hz far from each other according to the modulation mode (2k or 8k). Structure of OFDM carriers [13] There are some reserved, so-called Transmission Parameter Signalling (TPS) carriers that do not transfer payload, just provide transmission mode information for the receiver, so the total number of useful carriers is 1512 and 6048 respectively in the two transmission modes, and the resultant bit rate is between 4,97 and 31,66 Mbit/s, depending on the modulation (QPSK, 16-QAM or 64-QAM), the transmission mode (2k or 8k), the Code Rate (CR) used for error correction and the selected Guard Interval (GI). This guard interval means that there is a small time gap between each symbol, so the transmission is not continuous. This guarding time enables perfect reception by eliminating the errors caused by multipath propagation.[4, 79-90; 13] Frequency spectrum In 2k mode, 1705 carriers are modulated in the 8 MHz TV channel, so each carrier is 4462 Hz far from its neighbor, while in 8k mode this distance is 1116 Hz. In digital broadcasting, there are no vision and sound carriers, so the power for each carrier is the same. This mean High Performance Wireless Telecommunications Modulation High Performance Wireless Telecommunications Modulation Introduction The primary goal of the project is to analyze of OFDM system and to assess the suitability of OFDM as a modulation technique for wireless communications. In the part of project is covered two leading successfully implementation of OFDM based technologies are Digital Video Broadcasting (DVB-T and DVB-H) and Long Term Evolution (LTE advanced for 4G). Wireless communications is an emerging field, which has seen enormous growth in the last several years. The huge uptake rate of mobile phone technology, Wireless Local Area Networks (WLAN) and the exponential growth of the Internet have resulted in an increased demand for new methods of obtaining high capacity wireless networks. For cellular mobile applications, we will see in the near future a complete convergence of mobile phone technology, computing, Internet access, and potentially many multimedia applications such as video and high quality audio. In fact, some may argue that this convergence has already largely occurred, with the advent of being able to send and receive data using a notebook computer and a mobile phone. The goal of third and fourth generation mobile networks is to provide users with a high data rate, and to provide a wider range of services, such as voice communications, videophones, and high speed Internet access. The higher data rate of future mobile networks will be achieved by increasing the amount of spectrum allocated to the service and by improvements in the spectral efficiency. OFDM is a potential candidate for the physical layer of fourth generation mobile systems. Basic Principles of OFDM OFDM overview The Orthogonal Frequency Division Multiplexing (OFDM) is a modulation technique where multiple low data rate carriers are combined by a transmitter to form a composite high data rate transmission. The first commercial use of OFDM in the communication field was in the 1980s, and it was later widely used in the broadcast audio and video field in the 1990s in such areas as, ADSL, VHDSL, ETSI standard digital audio broadcast (DAB), digital video broadcast (DVB), and high-definition digital TV (HDTV). Digital signal processing makes OFDM possible. To implement the multiple carrier scheme using a bank of parallel modulators would not be very efficient in analog hardware. However, in the digital domain, multi-carrier modulation can be done efficiently with currently available DSP hardware and software. Not only can it be done, but it can also be made very flexible and programmable. This allows OFDM to make maximum use of available bandwidth and to be able to adapt to changing system requirements. Figure 1 is illustrated, Instead of separate modulators; the outgoing waveform is created by executing a high-speed inverse DFT on a set of time-samples of the transmitted data (post modulation). The output of the DFT can be directly modulated onto the outgoing carrier, without requiring any other components. Each carrier in an OFDM system is a sinusoid with a frequency that is an integer multiple of a base or fundamental sinusoid frequency. Therefore, each carrier is like a Fourier series component of the composite signal. In fact, it will be shown later that an OFDM signal is created in the frequency domain, and then transformed into the time domain via the Discrete Fourier Transform (DFT). Two periodic signals are orthogonal when the integral of their product, over one period, is equal to zero. This is true of certain sinusoids as illustrated in Equation 1. Definition of Orthogonal The carriers of an OFDM system are sinusoids that meet this requirement because each one is a multiple of a fundamental frequency. Each one has an integer number of cycles in the fundamental period. [2, 145-153; 6] The importantance of being orthogonal The main concept in OFDM is orthogonality of the sub-carriers.Since the carriers are all sine/cosine wave, we know that area under one period of a sine or a cosine wave is zero. Lets take a sine wave of frequency m and multiply it by a sinusoid (sine or a cosine) of a frequency n, where both m and n are integers. The integral or the area under this product is given by These two components are each a sinusoid, so the integral is equal to zero over one period. When we multiply a sinusoid of frequency n by a sinusoid of frequency m/n the area under the product is zero. In general for all integers n and m , sin(mx), cos(mx), cos(nx) , sin(nx) are all orthogonal to each other. These frequencies are called harmonics. Making the subcarriers mathematically orthogonal was a breakthrough for OFDM because it enables OFDM receivers to separate the subcarriers via an FFT and eliminate the guard bands. As figure 3 shows, OFDM subcarriers can overlap to make full use of the spectrum, but at the peak of each subcarrier spectrum, the power in all the other subcarriers is zero. OFDM therefore offers higher data capacity in a given spectrum while allowing a simpler system design. Creating orthogonal subcarriers in the transmitter is easy using an inverse FFT. To ensure that this orthogonality is maintained at the receiver (so that the subcarriers are not misaligned), the system must keep the transmitter and receiver clocks closely synchronizedwithin 2 parts per million in 802.11a systems. The 802.11a standard therefore dedicates four of its 52 subcarriers as pilots that enable phase-lock loops in the receiver to track the phase and frequency of the incoming signal. The 802.11a standard therefore dedicates four of its 52 subcarriers as pilots that enable phase-lock loops in the receiver to track the phase and frequency of the incoming signal. This method also eliminates low-frequency phase noise.Separating the subcarriers via an FFT require about an order of magnitude fewer multiply-accumulate operations than individually filtering each carrier. In general, an FFT implementation is much simpler than the RAKE receivers used for CDMA and the decision-feedback equalizers for TDMA.This idea are key to understanding OFDM. The orthogonality allows simultaneously transmission on a lot of sub- carriers in a tight frequency space without interference form each other. In essence this is similar to CDMA, where codes are used to make data sequences independent (also orthogonal) which allows many independent users to transmitin same space successfully.[2, 153-154; 6 ; 7] OFDM Operation Preliminary Concepts When the DFT (Discrete Fourier Transform) of a time signal is taken, the frequency domain results are a function of the time sampling period and the number of samples as shown in Figure 4. The fundamental frequency of the DFT is equal to 1/NT (1/total sample time). Each frequency represented in the DFT is an integer multiple of the fundamental frequency. Parameter Mapping from Time to Frequency for the DFT The maximum frequency that can be represented by a time signal sampled at rate 1/T is fmax = 1/2T as given by the Nyquist sampling theorem. This frequency is located in the center of the DFT points. All frequencies beyond that point are images of the representative frequencies. The maximum frequency bin of the DFT is equal to the sampling frequency (1/T) minus one fundamental (1/NT).The IDFT (Inverse Discrete Fourier Transform) performs the opposite operation to the DFT. It takes a signal defined by frequency components and converts them to a time signal. The parameter mapping is the same as for the DFT. The time duration of the IDFT time signal is equal to the number of DFT bins (N) times the sampling period (T).It is perfectly valid to generate a signal in the frequency domain, and convert it to a time domain equivalent for practical use (The frequency domain is a mathematical tool used for analysis. Anything usable by the real world must be converted into a real, time domain signal). This is how modulation is applied in OFDM. In practice the Fast Fourier Transform (FFT) and IFFT are used in place of the DFT and IDFT, so all further references will be to FFT and IFFT.[1 ,118 ; 4] Definition of Carriers The maximum number of carriers used by OFDM is limited by the size of the IFFT. This is determined as follows in Equation 2. OFDM Carrier Count In order to generate a real-valued time signal, OFDM (frequency) carriers must be defined in complex conjugate pairs, which are symmetric about the Nyquist frequency (fmax). This puts the number of potential carriers equal to the IFFT size/2. The Nyquist frequency is the symmetry point, so it cannot be part of a complex conjugate pair. The DC component also has no complex conjugate. These two points cannot be used as carriers so they are subtracted from the total available. If the carriers are not defined in conjugate pairs, then the IFFT will result in a time domain signal that has imaginary components. This must be a viable option as there are OFDM systems defined with carrier counts that exceed the limit for real-valued time signals given in Equation 2.In general, a system with IFFT size 256 and carrier count 216. This design must result in a complex time waveform. Further processing would require some sort of quadrature technique (use of parallel sine and cosine processing paths). In this report, only real-value time signals will be treated, but in order to obtain maximum bandwidth efficiency from OFDM, the complex time signal may be preferred (possibly an analogous situation to QPSK vs. BPSK). Equation 2, for the complex time waveform, has all IFFT bins available as carriers except the DC bin. Both IFFT size and assignment (selection) of carriers can be dynamic. The transmitter and receiver just have to use the same parameters. This is one of the advantages of OFDM. Its bandwidth usage (and bit rate) can be varied according to varying user requirements. A simple control message from a base station can change a mobile units IFFT size and carrier selection.[2,199-206; 4] Modulation Binary data from a memory device or from a digital processing stream is used as the modulating (baseband) signal. The following steps may be carried out in order to apply modulation to the carriers in OFDM: combine the binary data into symbols according to the number of bits/symbol selected convert the serial symbol stream into parallel segments according to the number of carriers, and form carrier symbol sequences apply differential coding to each carrier symbol sequence convert each symbol into a complex phase representation assign each carrier sequence to the appropriate IFFT bin, including the complex conjugates take the IFFT of the result OFDM modulation is applied in the frequency domain. Figure 5 and Figure 6 give an example of modulated OFDM carriers for one symbol period, prior to IFFT. OFDM Carrier Magnitude prior to IFFT For this example, there are 4 carriers, the IFFT bin size is 64, and there is only 1 bit per symbol. The magnitude of each carrier is 1, but it could be scaled to any value. The phase for each carrier is either 0 or 180 degrees, according to the symbol being sent. The phase determines the value of the symbol (binary in this case, either a 1 or a 0). In the example, the first 3 bits (the first 3 carriers) are 0, and the 4th bit (4th carrier) is a 1. OFDM Carrier Phase prior to IFFT Note that the modulated OFDM signal is nothing more than a group of delta (impulse) functions, each with a phase determined by the modulating symbol. In addition, note that the frequency separation between each delta is proportional to 1/N where N is the number of IFFT bins. The frequency domain representation of the OFDM is described in Equation 3. OFDM Frequency Domain Representation (one symbol period) After the modulation is applied, an IFFT is performed to generate one symbol period in the time domain. The IFFT result is shown in 7. It is clear that the OFDM signal has varying amplitude. It is very important that the amplitude variations be kept intact as they define the content of the signal. If the amplitude is clipped or modified, then an FFT of the signal would no longer result in the original frequency characteristics, and the modulation may be lost. This is one of the drawbacks of OFDM, the fact that it requires linear amplification. In addition, very large amplitude peaks may occur depending on how the sinusoids line up, so the peak-to-average power ratio is high. This means that the linear amplifier has to have a large dynamic range to avoid distorting the peaks. The result is a linear amplifier with a constant, high bias current resulting in very poor power efficiency. OFDM Signal, 1 Symbol Period Figure 8 is provided to illustrate the time components of the OFDM signal. The IFFT transforms each complex conjugate pair of delta functions (each carrier) into a real-valued, pure sinusoid. Figure 8 shows the separate sinusoids that make up the composite OFDM waveform given in Figure 7. The one sinusoid with 180 phase shift is clearly visible as is the frequency difference between each of the 4 sinusoids. Transmission The key to the uniqueness and desirability of OFDM is the relationship between the carrier frequencies and the symbol rate. Each carrier frequency is separated by a multiple of 1/NT (Hz). The symbol rate (R) for each carrier is 1/NT (symbols/sec). The effect of the symbol rate on each OFDM carrier is to add a sin(x)/x shape to each carriers spectrum. The nulls of the sin(x)/x (for each carrier) are at integer multiples of 1/NT. The peak (for each carrier) is at the carrier frequency k/NT. Therefore, each carrier frequency is located at the nulls for all the other carriers. This means that none of the carriers will interfere with each other during transmission, although their spectrums overlap. The ability to space carriers so closely together is very bandwidth efficient. OFDM Time Waveform Figure 9 shows the OFDM time waveform for the same signal. There are 100 symbol periods in the signal. Each symbol period is 64 samples long (100 x 64 = 6400 total samples). Each symbol period contains 4 carriers each of which carries 1 symbol. Each symbol carries 1 bit. Note that Figure 9 again illustrates the large dynamic range of the OFDM waveform envelope. OFDM Spectrum Figure 10 shows the spectrum for of an OFDM signal with the following characteristics: 1 bit / symbol 100 symbols / carrier (i.e. a sequence of 100 symbol periods) 4 carriers 64 IFFT bins spectrum averaged for every 20 symbols (100/20 = 5 averages) Red diamonds mark all of the available carrier frequencies. Note that the nulls of the spectrums line up with the unused frequencies. The four active carriers each have peaks at carrier frequencies. It is clear that the active carriers have nulls in their spectrums at each of the unused frequencies (otherwise, the nulls would not exist). Although it cannot be seen in the figure, the active frequencies also have spectral nulls at the adjacent active frequencies. It is not currently practical to generate the OFDM signal directly at RF rates, so it must be up converted for transmission. To remain in the discrete domain, the OFDM could be upsampled and added to a discrete carrier frequency. This carrier could be an intermediate frequency whose sample rate is handled by current technology. It could then be converted to analog and increased to the final transmit frequency using analog frequency conversion methods. Alternatively, the OFDM modulation could be immediately converted to analog and directly increased to the desired RF transmits frequency. Either way, the selected technique would have to involve some form of linear AM (possibly implemented with a mixer). [1, 122-125; 6] Reception and Demodulation The received OFDM signal is down converted (in frequency) and taken from analog to digital. Demodulation is done in the frequency domain (just as modulation was). The following steps may be taken to demodulate the OFDM: partition the input stream into vectors representing each symbol period take the FFT of each symbol period vector extract the carrier FFT bins and calculate the phase of each calculate the phase difference, from one symbol period to the next, for each carrier decode each phase into binary data sort the data into the appropriate order OFDM Carrier Magnitude following FFT Figure 11 and Figure 12 show the magnitude and spectrum of the FFT for one received OFDM symbol period. For this example, there are 4 carriers, the IFFT bin size is 64, there is 1 bit per symbol, and the signal was sent through a channel with AWGN having an SNR of 8 dB. The figures show that, under these conditions, the modulated symbols are very easy to recover. OFDM Carrier Phase following FFT In Figure 12 that the unused frequency bins contain widely varying phase values. These bins are not decoded, so it does not matter, but the result is of interest. Even if the noise is removed from the channel, these phase variations still occur. It must be a result of the IFFT/FFT operations generating very small complex values (very close to 0) for the unused carriers. The phases are a result of these values. [1, 125 -128; 3] OFDM transceiver OFDM signals are typically generated digitally due to the difficulty in creating large banks of phase lock oscillators and receivers in the analog domain. Figure 13 shows the block diagram of a typical OFDM transceiver. The transmitter section converts digital data to be transmitted, into a mapping of subcarrier amplitude and phase. It then transforms this spectral representation of the data into the time domain using an Inverse Discrete Fourier Transform (IDFT). The Inverse Fast Fourier Transform (IFFT) performs the same operations as an IDFT, except that it is much more computationally efficiency, and so is used in all practical systems. In order to transmit the OFDM signal the calculated time domain signal is then mixed up to the required frequency. Block diagram showing a basic OFDM transceiver [3] The receiver performs the reverse operation of the transmitter, mixing the RF signal to base band for processing, then using a Fast Fourier Transform (FFT) to analyze the signal in the frequency domain. The amplitude and phase of the subcarriers is then picked out and converted back to digital data. The IFFT and the FFT are complementary function and the most appropriate term depends on whether the signal is being received or generated. In cases where the Signal is independent of this distinction then the term FFT and IFFT is used interchangeably. [1, 125 -128, 3] Analysis of OFDM characteristics Guard Period OFDM demodulation must be synchronized with the start and end of the transmitted symbol period. If it is not, then ISI will occur (since information will be decoded and combined for 2 adjacent symbol periods). ICI will also occur because orthogonality will be lost (integrals of the carrier products will no longer be zero over the integration period), To help solve this problem, a guard interval is added to each OFDM symbol period. The first thought of how to do this might be to simply make the symbol period longer, so that the demodulator does not have to be so precise in picking the period beginning and end, and decoding is always done inside a single period. This would fix the ISI problem, but not the ICI problem. If a complete period is not integrated (via FFT), orthogonality will be lost. The effect of ISI on an OFDM signal can be further improved by the addition of a guard period to the start of each symbol. This guard period is a cyclic copy that extends the length of the symbol waveform. Each subcarrier, in the data section of the symbol, (i.e. the OFDM symbol with no guard period added, which is equal to the length of the IFFT size used to generate the signal) has an integer number of cycles. Because of this, placing copies of the symbol end-to-end results in a continuous signal, with no discontinuities at the joins. Thus by copying the end of a symbol and appending this to the start results in a longer symbol time. Addition of a guard period to an OFDM signal [3] In Figure 14, The total length of the symbol is Ts=TG + TFFT, where Ts is the total length of the symbol in samples, TG is the length of the guard period in samples, and TFFT is the size of the IFFT used to generate the OFDM signal. In addition to protecting the OFDM from ISI, the guard period also provides protection against time-offset errors in the receiver. For an OFDM system that has the same sample rate for both the transmitter and receiver, it must use the same FFT size at both the receiver and transmitted signal in order to maintain subcarrier orthogonality. Each received symbol has TG + TFFT samples due to the added guard period. The receiver only needs TFFT samples of the received symbol to decode the signal. The remaining TG samples are redundant and are not needed. For an ideal channel with no delay spread the receiver can pick any time offset, up to the length of the guard period, and still get the correct number of samples, without crossing a symbol boundary. Function of the guard period for protecting against ISI [3] Figure 15 shows this effect. Adding a guard period allows time for the transient part of the signal to decay, so that the FFT is taken from a steady state portion of the symbol. This eliminates the effect of ISI provided that the guard period is longer than the delay spread of the radio channel. The remaining effects caused by the multipath, such as amplitude scaling and phase rotation are corrected for by channel equalization. In order to avoid ISI and ICI, the guard period must be formed by a cyclic extension of the symbol period. This is done by taking symbol period samples from the end of the period and appending them to the front of the period. The concept of being able to do this, and what it means, comes from the nature of the IFFT/FFT process. When the IFFT is taken for a symbol period (during OFDM modulation), the resulting time sample sequence is technically periodic. This is because the IFFT/FFT is an extension of the Fourier Transform which is an extension of the Fourier Series for periodic waveforms. All of these transforms operate on signals with either real or manufactured periodicity. For the IFFT/FFT, the period is the number of samples used. Guard Period via Cyclic Extension With the cyclic extension, the symbol period is longer, but it represents the exact same frequency spectrum. As long as the correct number of samples are taken for the decode, they may be taken anywhere within the extended symbol. Since a complete period is integrated, orthogonality is maintained. Therefore, both ISI and ICI are eliminated. Note that some bandwidth efficiency is lost with the addition of the guard period (symbol period is increased and symbol rate is decreased) [2,154-160, 3] Windowing The OFDM signal is made up of a series of IFFTs that are concatenated to each other. At each symbol period boundary, there is a signal discontinuity due to the differences between the end of one period and the start of the next. These discontinuities can cause high frequency spectral noise to be generated (because they look like very fast transitions of the time waveform). To avoid this, a window function (Hamming, Hanning, Blackman, ) may be applied to each symbol period. The window function would attenuate the time waveform at the start and the end of each period, so that the discontinuities are smaller, and the high frequency noise is reduced. However, this attenuation distorts the signal and some of the desired frequency content is lost.[1, 121;2 154] Multipath Characteristics OFDM avoids frequency selective fading and ISI by providing relatively long symbol periods for a given data rate. This is illustrated in Figure 17. For a given transmission channel and a given source data rate, OFDM can provide better multipath characteristics than a single carrier. OFDM vs. Single Carrier, Multipath Characteristic Comparison However, since the OFDM carriers are spread over a frequency range, there still may be some frequency selective attenuation on a time-varying basis. A deep fade on a particular frequency may cause the loss of data on that frequency for a given time, but the use of Forward Error Coding can fix it. If a single carrier experienced a deep fade, too many consecutive symbols may be lost and correction coding may be ineffective. [8] Bandwidth A comparison of RF transmits bandwidth between OFDM and a single carrier is shown in Figure 18 (using the same example parameters as in Figure 17). OFDM Bandwidth Efficiency In Figure 18, the calculations show that OFDM is more bandwidth efficient than a single carrier. Note that another efficient aspect of OFDM is that a single transmitters bandwidth can be increased incrementally by addition of more adjacent carriers. In addition, no bandwidth buffers are needed between transmit bandwidths of separate transmitters as long as orthogonality can be maintained between all the carriers.[2, 161-163; 8; 9] Physical Implementation Since OFDM is carried out in the digital domain, there are many ways it can be implemented. Some options are provided in the following list. Each of these options should be viable given current technology: ASIC (Application Specific Integrated Circuit) ASICs are the fastest, smallest, and lowest power way to implement OFDM Cannot change the ASIC after it is built without designing a new chip General-purpose Microprocessor or MicroController PowerPC 7400 or other processor capable of fast vector operations Highly programmable Needs memory and other peripheral chips Uses the most power and space, and would be the slowest Field-Programmable Gate Array (FPGA) An FPGA combines the speed, power, and density attributes of an ASIC with the programmability of a general purpose processor. An FPGA could be reprogrammed for new functions by a base station to meet future (currently unknown requirements).This should be the best choice.[9] OFDM uses in DVB (Digital Video Broadcasting) DVB (Digital Video Broadcast) is a set of standards for the digital transmission of video and audio streams, and also data transmission. The DVB standards are maintained by the DVB Project, which is an industry-led consortium of over 260 broadcasters, manufacturers, network operators, software developers, regulatory bodies and others in over 35 countries. DVB has been implemented over satellite (DVB-S, DVB-S2), cable (DVB-C), terrestrial broadcasting (DVB-T), and handheld terminals (DVB-H). the DVB standard following the logical progression of signal processing steps, as well as source and channel coding, COFDM modulation, MPEG compression and multiplexing methods, conditional access and set-top box Technology. In this project is presented an investigation of two OFDM based DVB standards, DVB-T and DVB-H. DVB-T (Digital Video Broadcasting Terrestrial) The first Terrestrial Digital Video Broadcasting pilot transmissions were started in the late 90s, and the first commercial system was established in Great Britain. In the next few years the digital broadcasting system has been set up in many countries, and the boom of the digital terrestrial transmission is estimated in the next few years, while the analogue transmission will be cancelled within about 15 years. The greatest advantage of the digital system is the effective use of the frequency spectrum and its lower radiated power in comparison with the analogue transmission, while the covered area remains the same. Another key feature is the possibility of designing a so-called Single Frequency Network (SFN), which means that the neighboring broadcast stations use the same frequency and the adjacent signals dont get interfered. The digital system transmits a data stream, which means that not only television signals but data communication (e.g. Internet service) may be used according to the demands. The data stream consists of an MPEG-2 bit stream, which means a compression is used, enabling the transfer of even 4 or 5 television via the standard 8 MHz wide TV channel. For the viewer, the main advantages are the perfect, noise-free picture, CD quality sound, and easier handling, as well as services like Super Teletext, Electronic Programme Guide, interactivity and mobility.[11, 251-253] Modulation technique in DVB-T The DVB-T Orthogonal Frequency Division Multiplexing (OFDM) modulation system uses multi-carrier transmission. There are 2 modes, the so-called 2k and 8k modes, using 1705 and 6817 carriers respectively, with each carrier modulated separately and transmitted in the 8 MHz TV channel. The common modulation for the carriers is typically QPSK, 16-QAM or 64-QAM. Each signal can be divided into two, so-called „In Phase (I) and „Quadrature Phase components, being a 90Â ° phase shift between them. The constellation diagram and the bit allocation is shown in bellow 16-QAM constellation diagram and bit allocation [6] This modulation can be demonstrated in the constellation diagram, where the 2 axes represent the 2 components (I and Q). In case of using 16-QAM modulation, the number of states is 16, so 1 symbol represents 4 bits. [11, 255; 6; 14] Bir errors If we simulate all the carriers in the constellation diagram we get not just 1 discrete point, but many points, forming a „cloud and representing each state. In case of additive noise the „cloud gets bigger and the receiver may decide incorrectly, resulting in bit errors. Figure 2 shows the measured constellation diagram without and with additive noise. Measured 16-QAM constellation diagram a) without additive noise b) with additive noise [6] To ensure perfect picture quality, the DVB-T system uses a 2 level error correction (Reed-Solomon and Viterbi). This corrects the bad bits at an even 10-4 Bit Error Rate (BER) and enables error-free data transmission. [13, 32-36] The multi-carrier structure The structure of carriers can be illustrated also in the function of time (Figure 20). The horizontal axis is the frequency and the vertical axis is the time. The 8 MHz channel consists of many carriers, placed 4462 Hz or 1116 Hz far from each other according to the modulation mode (2k or 8k). Structure of OFDM carriers [13] There are some reserved, so-called Transmission Parameter Signalling (TPS) carriers that do not transfer payload, just provide transmission mode information for the receiver, so the total number of useful carriers is 1512 and 6048 respectively in the two transmission modes, and the resultant bit rate is between 4,97 and 31,66 Mbit/s, depending on the modulation (QPSK, 16-QAM or 64-QAM), the transmission mode (2k or 8k), the Code Rate (CR) used for error correction and the selected Guard Interval (GI). This guard interval means that there is a small time gap between each symbol, so the transmission is not continuous. This guarding time enables perfect reception by eliminating the errors caused by multipath propagation.[4, 79-90; 13] Frequency spectrum In 2k mode, 1705 carriers are modulated in the 8 MHz TV channel, so each carrier is 4462 Hz far from its neighbor, while in 8k mode this distance is 1116 Hz. In digital broadcasting, there are no vision and sound carriers, so the power for each carrier is the same. This mean