Differences Between Linear Block And Convolutional Codes Computer Science Essay

Differences Between Linear Block And Convolutional Codes Computer Science Essay Generally the coding theory is the detailed analysis of the properties of the codes and their suitable quality for the identified application. Codes are mainly used in cryptography, error correction , data compression and now a days it is also used for the network coding.this coding generally involves with the linear block codes, convolutional codes, turbo codes respectively. LINEAR BLOCK CODES: In coding theory, the linear block code generally referred as a error correcting code for which the obtained resultant codeword is the linear combination of any two codewords. In simple words, the linear block code possesss the linearity property that is the sum of any two codewords is also a codeword. These linear block codes are divided in to the block odes and convolutional codes, eventhough turbo codes is the combination of these two types. More efficient encoding and decodig algorithms are provided by the linear codes when compared with the other codes. (http:// en.wikipedia.org/wiki/linear codes). CONVOLUTIONAL CODES The main principle involved in the convolutional code is the weighted sum of the various input message symbols is the resultant codeword symbol. This resemblance the convolution used in the LTI systems where we find the output of a syatem by knowing the impulse response and the respective input. So hence the output of a convolutional encoder can be obtained by the convolution of the input bits with the states of the convolution encoder registers.(http://en.wikipedia.org/wiki/convolutional codes). TURBO CODES In 1993, turbo codes are developed which are the class of high performance forward error correction codes and they are also the first practical codes to come nearer to the chgannel capacity for the code rate at which reliable communication is still possible while a specific identified noise level is given. Berrou glavieux and thitimajshima introduced these turbo codes in 1993 in their paper named near Shannon limit error correcting and decoding : turbo codes. Once after the introduction of these parallel turbo codes many other types are discovered which mainly includes repeat accumulate codes, serial versions. Even the conventional FEC systems are also been applied by the iterative turbo decoding methods. (http://en.wikipedia.org/wiki/turbo ) 2. CORE OF THE PAPER 1. PRINCIPLES OF THE LINEAR BLOCK CODES A block code of length n and codewors is said to be a linear(n, k) code if and only if the k dimensional subspace of the vector space is formed by all the codewords of all the n- tuples over GF(2). A linear code of length n and rank K is the linear subspace C with dimension K of the vector space where is the finite field consisting of the q elements. Such tytpe of a code with parameter q is called a q ary code. The code is said to be as binary code or ternary code if and only if q =2 or q=3 respectively. Linear block codes are briefly described by their symbol alphabets (example: binary, ternary) and with parameters (n,m, ) where n is the codeword length in symbols. m is the total number of source symbols which are used for encoding. is the codes minimum hamming distance. Linear block codes are of many types they are: Cyclic codes Repetition codes Parity codes Polynomial codes Reed Solomon codes Algebraic geometric codes Reed muller codes Perfect codes. A. GENERATOR MATRIX AND PARITY CHECK MATRIX Since the linear codes could be considered as a linear subspace C of , so any codeword C can be represented as a linear combination of a set of basis vectors such that , C= ++.= mG Where G is the generator matrix and m is the message. B. THEORITICAL CONCEPTS: As linear subspace of , the span of the minimal set of codewords can be represented by the entire code word C. These obtained codewords are collected and combined in the rows of the matrix G known as generator matrix for the code C. Theoretically, it is the standard form of is given as G=(/A), where is the kk identity matrix and A is k(n-k) matrix. A check matrix is defined as the matrix which represents the linear function H: whose kernel is C. The generating matrix G in standard form, G=(/A), with C as a code then H=(/) is a check matrix for C. C .HAMMING CODES Hamming codes are the first codes developed for the purpose of the error correction. These are widely used in digital communication systems. For any positive integer r>=2, there exists a [-r-1,3] hamming code. Example: given the following generator matrix and parity check matrix, the linear block code is [7,4,3] hamming code. G= , D. HADAMARD CODE Hadamard codes is capable of correcting many errors and is a [, r,] linear code. Hadamard code has minimum distance and therefore can correct -1 errors. Example  : The linear block code with the following generator matrix is a [8,3,4]2 Hadamard code: E..MERITS: Linear codes are the very prominent calss of the error correcting codes. It generally includes the simple description, easy procedure for encoding, nice properties, conceptually easy decoding. If C is a linear code then the minimum distance d(c) is easy to compute. Linear codes possesss simple specifications. To specify the (n,k) linear code it is sufficient to list K linearly independent codewords where as for the non linear code words generally we have to represent with all the code words. The most important linear block codes are: Hamming codes, cyclic codes, reed Solomon codes, BCH codes, LDPC codes, turbo codes respectively. F. DEMERITS: The main drawback of the hamming code is that it has the fixed hamming distance and also it is very difficult to implement coders for large block. The detection of two error bits and ability to correct the single errored bit can be obtained from the fixed hamming distance.if we choose a code which generally allows the implementor to select the desired hamming distance will be useful or beneficial. Hammer coder practical largest possible allows for codewords of nearly 31bits only. G. APPLICATIONS (1) These linear block properties are used in many applications. Trellis shaping is generated by using the syndrome coset uniqueness property of linear block codes. (2) these are also used in sensor networks for distributed sourcecoding. (3)by using these codes phase shift can be easily corrected and detected and also multiple signals can be easily sent from onechannel. (4) some other applications include mobile phone systems which are used in CDMA. (references: William E.ryan and shu lin(2009) channel codes: classical and modern, Cambridge university press.,Thomas M. corer and joy A. Thomas(1991) elements of information theory john wiley and sons). 2.PRINCIPLES OF CONVOLUTIONAL CODES Convolutional codes comes under a category of error correction codes in which an n bit symbol consists of each m bit information symbol to be encoded where coderate is m/n (n>=m) and the transformation acts as a function of the last K information symbols, here the constraint lenghht of the code is denoted by K. A. .Convolutional encoder To encode data convolutinoally, we begin with K memory reegisters holding one input bit each. Until other value specified , the 0 is the initial value af all memory registers. The encoder includes n-modulo 2 adders( it can be put effort with single Boolean XOR gate ) and n generator polynomials- each adder has one of them. The left most register is feded with the an input bit m. By using those existing values in the remaining registers and the respective generatot polynomials the n bits are the encoder outputs. By bit shifting all register values to their right and have to wait for its next input input bit. The encoder continues output until all registers have returned to the zero state if there are no remaining input bits. The below figure shows the rate 1/3 of the encoder with k value (constraint length) of 3. And also the generator polynomials are =(1,1,1), =(0,1,1) and =(1,0,1) The calculation of the output bits are as follows n1 = m1 + m0 + m-1 n2 = m0 + m-1 n3 = m1 + m-1. Img.1. Rate 1/3 non-recursive, non-systematic convolutional encoder with constraint length 3. B. RECURSIVE AND NON RECURSIVE CODES The above figure shows the encoder where as the below one shows the recursive one respectively, Rate 1/2 recursive, systematic convolutional encoder with constraint length 4. It can be easily observed that the input which is encoded is included in the output sequence also. These codes are generally called as systematic. The another type of codes are generally called as non systematic codes. Generally the systematic codes are always recursive codes where as the non systematic codes are always non recursive codes. The name convolutional encoder came for it because it carry out a convolution of the input stream with the encoders impulse responses. = Where x is an input sequence, is an output sequence from output j and which is the impulse response of the output j. The discrete lineaqr time invariant system is also called as a convolutional encoder. The own transfer function itself describes the output of an encoder. The transfer function is connected by the impulse response through z transform. + (Z)= +, (Z)=1+. The second order transfer functions are: (z)= We Define m by Where for any rational functional, we define it as Where m is the maximum polynomial degrees of the . And the constraint length is defined as . C.TRELLIS DIAGRAM A convolutional encoder is also referred as finite state machine. An encoder with n binary cells produce states. Just imagine the encoder which is shown in figure 1 has 1 in left memory cell(m0) in right one. We will refer such a stete as 10. By considering input bit the encoder at the next turn can convert either to 11 state or 01 state or 01 state. from the below figure we get rhe idea of decoding if the received sequence doesnot suit this graph then it errors can be obtained and we should select closest correct sequence. All transitions which are possible are shown as below: The red line is the path of the trellis. The lines their indicate transitions where the dotted lines are 1 input and the proper lines rae 0 input. The path here represents an actual encoded sequence. One of the path is shown in red colour as an example. The figure provides an idea about the decoding. D.FREE DISTANCE AND THE ERROR DISTANCE The minimum distance between the different encoded sequences is called as the free distance. The number of errors that can be corrected by code is given as correcting capability. It is given as correcting capability. It is given as, F. DECODING CONVOLUTIONAL CODES Decoding the convolutional codes can be done by several algorithms . thye vviterbi algorithm is universally used for relatively small values of K as it is highly parallelizable and it also provides maximum likelihood performance. By using SIMD instruction set the viterbi decoders are easy to implement the software on cpu and also in VLSI hardware. Fano algorithm is the best one among the several sequential decoding algorithms through which the longer constraint lenght codes re more practically decoded. Unlike viterbi decoding sequential decoding is not have maximum probability but there will be the slight incresase in the complexity with their constraint lengfht. Giving the chance to us the long , short constraint Length codes. In early 1970s these codes are used in the pionner program in Jupiter and Saturn but made it shorter, these viterbi decoded codes, often connecyed with large reed Solomon error correction codes which generally steeps the complete bit error rate curve and it also produces the very low residual undetected error rates. These both sequential and viterbi decoding algorithm gives the hard decisions..The codeword which is most likely formed by the bits.by using the soft output viterbi algorithm an appropriate confidence measure can be added to each bit in use with the BCJR algorithm the maximum a posterior(MAP ) Soft decisions can be obtained. G. POPULAR CONVOLUTIONAL CODES The viterbi decoded convolutiona;l codes is used for the voyagev program which has a constraint length of K=7, and also rate=1/2. The more powerful codes are produced by the longer constraint lengths but the viterbi algorithm complexity increases exponentially with respect to the constraint lengths , controlling these more powerful codes to deep space machines where the extra performance increases decoder complexity. Cassine probe, mars path finder, mars exploration rover to Saturn use of K=15 AND RATE OF 1/6, 2DB Bbetter than the simplex k=7, code at a rate of 256* in decoding complexity iss performed by this code. H. MERITS To correct the errors in noisy channels these convolutional codes are frequently used. These convolutional codes perform well on very bad conditions also. These convolutional codes are generally used often in satellite communications, mobile telephony and also in voice band modems. Convolutional codes generally gives good results in lower noise environments. Convolutional codes are also used in the voice band modems( v.,32, v.17, v.34) and also in the GSM mobile phones. I. DEMERITS Even though the convolutional encoder has the simplest procedure, decoding of it is very complex task. Convolutional codes cannot provide more protection against noise. J. APPLICATIONS Convolutional codes are used in the number of the applications which aims to achieve reliable data transfer, including radio, mobile communications, digital video communications, satellite communications. By using hard decision code, these codes are implemented in concatenation( example: reed Solomon). These are more efficient. (references: tutorial on convolutional coding and decoding, the online text book: IT, inference and leaving algorithms by david J.C.Mackay). 3. PRINCIPLES OF TURBO CODES By using the block code with convolutional code and also withthe longer constraint length and large block length it is theortically possible to approach the Shannon limit. But this approach became impractical due to the processing power required to decode. By using the recursive coders and iterative soft decoders the turbo codes overcome this drawback. The main aim of the recursive coder is to make the convolutional codes with shorter constraint lengths which appears as a large constraint length of a block codes and iterative soft decoder efficiently improves the estimation of the obtained message. The below shown figure generally gives the encoder for implementation which describes a clasiical encoder which provides the general design of the turbo codes. The 3 bits of the subblock can be sended by using this encoder implementation. The m-bit block of payload data is in the first subblock. The n/2 parity bits for a well known permutation includes in the 3rd subblock which is once aga in computed with the RSC code. The total number of bits in the code are . Interleaver is a device which generally carry outb the permutation of the payload data. This turbo code encoder includes two RSC codes (identical) , , as shown in the figure. By using the concatenation scheme these are connected to each othere which is reffered as parallel concatenation. Here M acts as a memory register. The input bits are forced to appear in different sequences by the dealy line and interleaver. The input sequence appears at both outputs after completion of first iteration [, , ] because of the encoders systematic nature. = = DECODER The serial connection of two elementary decoders is said to be a decoder. Generally decoder only operates on the lower speed( ) , thus it is planned for the encoder and is for encoder. The produces delays and also hold a soft decision. Where as produces delay respectively. The error bursts which are coming from the output are scattered by the interleaver whicvh is installed between between the two decoders. Here DI refers to demultiplexing and insertion module here it acts as a switch, it generally redirects input bits to once and to at another. It feeds both , inputs with padding bits( zeroes) in off state. While considering a memory less AWGN channel and assumption is made that at the iteration, the decoder receives a pair of random variables. =(-1)+, =2(-1)+ . Here is a bit from output of encoder and , are independent noise components consists of same produces a soft decision ie; ) = and pass it to the . generally referred as logarithm of likelihood ratio. The posterior probability (APP) of bit data is defined as which shows the probability of explaining a received bit as i. But where as produces a hard decision which is a decoded bit. Viterbi algorithm is unappropiate to calculate APP, it is not used in a BCJR algorithm is used but where as for viterbi algorithm is an appropriate one. MERITS Up to now, we know so many practical error correction methods but turbo codes and low density parity check codes come very close to approach the Shannon limit , which is the theoretical limit of maximum transfer reate of information over a noisy channel. Turbo codes increases data rate with out increasing the transmitted power, or to transmit at a certain data rate they are used to decrease the amount of the power. It generally produces the best performance results pof the throughput and latency. DEMERITS Its main disadavantage is the complexity of the relative high decoding. It also has relatively high latency, which is not suitable for some applications. It is also not verymuch useful for the satellites why because the latency is produced by the transmission distance due to the limited speed of the light. These algorithms are complex in nature. APPLICATIONS 3G and 4G mobile telephony standards uses turbo codes widely. Examples: HSPA and LTE . Used in media FLO and QUALCOMM Turbo codes are also useful in NASA missions such as mars re connaissance orbiter which is another option to RS- viterbi codes. IEEE802.16 generally uses the block turbo coding and CTC(WIMAX) a wireless metropolitan standard. Turbo codes are used in the designs of the digital communication systems and also in detection, demodulation. Turbo codes in the field of the error correcting codes represents a significant development. The cable transmission, short distance communications or data storage are the future applications of the turbo codes. (references: Berrou, claude; glavieux, alian , punva, near Shannon limit error- correcting, Berrou, claude, the ten years old turbo codes are entering in to the service, france). 4. CRITICAL COMPARISION LINEAR BLOCK CODES AND CONVOLUTIONAL CODES: Convolutional codes have a regular, natural, trellis structure which are useful in the implementation of the viterbi algorithm. Where as the linear block codes have a natural but it has minimal trellis structure. In both convolutional codes and linear block codes, the estimation of viterbi algorithm can be done by number of trellis edge symbol per encoded bit. Generally convolutional codes does not provide more protection against noise than the linear block codes. Convolutional codes offers greater simplicity of implementation over a linear block codes in many cases. Convolutional codes may not have minimal trellis representation but where as the linear block codes has the minimal trellis structure. The main differences between the linear block codes and convolutional codes is that a system which is using the block codes will transmits the k data bits and then transmits the n-k reductant bits. Where as the system which uses the convolutionla codes produces n coded bits from k data bits and the codeword need not contain unaltered k data bits. The main difference between the convolutional encoder and the block encoder is that the block code related not only to the current , but also on the previous (u) number of fixed information blocks ,, That is given as, =++.. With out the memory a linear block code is merely a convolutional code. The theory of the linear block codes seems to be degenerate of the theory of the convolutional codes, the usual approach of the convolutional codes is to note the small and fixed values of n and k and also the varying values of . TURBO CODES V/S CONVOLUTIONAL CODES: There are some differences between the behaviour of turbo codes and the convolutional codes. As we know that the performance of the convolutional codes imcreases with the increasing constraint length( code complexity). This is not for the turbo codes where the best codes of the turbo codes have the small constraint lengths . With decreasing code rate the performance of the convolutional codes doesnot improve significantly. Where as for the turbo codes even for the lower coding rates it achieves a very significant coding gain. While seeing from the implementation point of view, soft output encoders and recursive decoders are essential in turbo code schemes, where as they are not that much essential in convolutional codes excluding the concatenated configuration. Criteria Convolutional codes turbo codes Larger constraint length good bad Lower coding rate indifferent good Larger free distance good indifferent Soft output decoders indiffernt good Recursive encoders Indifferent good Both the linear block codes and convolutional codes are most frequently used type codes in the practice of enginnering for the designing of the most useful codes. TURBO VS LINEAR BLOCK CODES: The turbo codes are the hybrid model of the both the linear block codes and the convolutional codes respectively. The linear block codes used in the turbo codes instead of the convolutional codes to form a turbo product code(TPC). Two hamming codes are concatenated serially with the absence of an interleaver in between them. They can perfoem well in low SNR and can be formed by any block code. The convolutional codes used in the turbo codes usually forms a parallel concatenated convolutional code(PCCC) which have the small constraint length. They are systematic. 5. SIMULATION RESULTS The simulation results of linear block codes are as follows : The dual adaptive importance sampling (DAIS) technique evaluates the word and bit error rates of linear block codes down to extreme low values. (reference: Slin and D. Costello, error correction coding : fundamentals and applications). T,he simulation of the convolutional codes are as follows: Simulations with two recursive , equal convolutional codes with an interleaver whose length is 400 and k=50, this generally provides manufacturer interoperability, because this technique achieves the improvements which is over 3.5 dB respectively over the trellis codification modulation. (reference:Concatened trellis/reed Solomon coding in DMT systems- Kschischarg). The simulation results of the turbo codes are as follows: At a rate of R=1/2 the simulation results of the turbo codes are obtained. Here length of the data block is 400 bits( assumption) and also a MAP decoder used in the simulation. From the results it is observed that for the first few iterations yield the most significant improvements in BER for any given value of . After that the results appear to converge on to a BER for each value of . ( reference: Andersen JD and zyablov vv, interleaver design for turbo coding). 6. CONCLUSION So, hence in this research paper we have discussed the principles, applications, merits and demerits of the linear block codes, convolutional codes, turbo codes respectively. We also discussed the main differences between the block codes, convolutional codes, turbo codes and presented their respective simulation results. Personally, by doing this research i learned a lot on this coding theory and also came to know the importance of these codes in the present world. The future applications of these codes are to provide the substantial improvements in communication for the satellites. 7. REFERNCES (1) code tables: bounds on the parameters of various types of the codes. (2) q- ary code generator program. (3) error correcting codes (ECC) page (4) Wikipedia articles in corporating text from the federal standarad convolutional codes with a 1037c. (5) turbo decoding as an instance of pearls belief propogation algorithm,. (6) IEEE journal on selected areas in communication- Robert J Mackay, David J.C. (7) Turbo equalisation : principles and new results an IEEE paper on communications.

Health Public Service Advertising Campaigns Health And Social Care Essay

Health Public Service Advertising Campaigns Health And Social Care Essay The flurry of advertisements associated with public service campaigns raises several questions regarding its worth and effectiveness. Public service advertisements (PSA) or announcements are promotional material that addresses problems assumed to be of general concern to citizens at large. PSA typically attempt to increase public awareness of such problems and their possible solutions, and in many instances also try to influence public beliefs, attitudes, and behavior concerning them (OKeefe, 1990). Most of the PSA deal with health of personal safety topics, including alcohol and drug abuse, preventive health care, traffic safety, nutrition etc. Some PSA also include environmental issues, educational and literacy issues, consumer issues, and general humanitarian concerns like hygiene and cleanliness issues. Mass media audiences are generally attentive and give positive reactions to such advertisements. Healthcare in India is the responsibility of constituent states and territories of India. The Constitution charges every state with raising of the level of nutrition and the standard of living of its people and the improvement of public health as among its primary duties. The National Health Policy was endorsed by the Parliament of India in 1983 and updated in 2002. Health related public service campaigns are the advertising campaigns that are run by the government to create awareness among public about diseases which are very dangerous. The Government of India has introduced various health programme and policies to improve the Indian citizens standard of living. Government chooses number of mediums to reach to the masses. For this the government uses television, newspaper, hoardings and radio. Sometimes rallies are also organized to create awareness among people. The example of these kind of campaigns are AIDS awareness campaign run by the government under the banner of national AIDS control organization (NACO), Campaign for tuberculosis, malaria and polio are other examples. Sometimes famous celebrities are taken in the advertisements to create more impact. The study has been undertaken with an objective to measure the effectiveness of health related public service advertisement campaigns which are run by the government of India. The study included three campaigns which are malaria, tuberculosis and AIDS, Over the years, an increasing level of insecticide-resistance has developed in the malarial vectors in many parts of the country, while the incidence of the more deadly P-Falciparum Malaria has risen to about 50 percent in the country as a whole. In respect of TB, the public health scenario has not shown any significant decline in the pool of infection amongst the community, and there has been a distressing trend in the increase of drug resistance to the type of infection prevailing in the country. A new and extremely virulent communicable disease HIV/AIDS has emerged on the health scene. As there is no existing therapeutic cure or vaccine for this infection, the disease constitutes a serious threat, not merely to public health but to economic development in the country also. (NHP 2002) Literature Review Public service advertising (PSA) campaigns are widespread around the Globe. Public service announcements are a type of advertising, sponsored by either government agencies or other organizations, to promote causes and activities generally considered socially desirable (Garbett, 1981). PSAs use paid as well as donated media for creating awareness for social issues. Such advertising is generally produced and distributed on a cooperative basis by governmental agencies or nonprofit organizations working in cooperation with private advertising and mass media companies. Generally the content or programming, while the participating advertising agency and media companies provide creative services, media planning and dissemination services on a not for profit basis. Studies have found no distinction in the effectiveness with the either type of media. Based on self-reported behavior from sample surveys and official count s of incapacitating and fatal highway accidents, in three market field ex periments comparing the effectiveness of Paid versus Donated Media in decreasing youth male drinking and driving, the study found both type of media strategies to be equally effective (Murry Jr., 1996). The placement of PSAs has long been debated and earlier studies reveal that most of the PSAs were being placed during non-prime time especially between 7am to 6pm on weekdays (Hannmen et al, 1973). However recent analysis of advertising pattern indicates more favorable time distribution. Same pattern has been observed in India also. In a study to explore effects of message framing of health advertisements and individual differences in temporal orientation on consumer risk perceptions, attitude, and behavioral intentions, Consumers temporal orientation moderates ad-framing effects related to goal pursuit strategies. The study demonstrates that a fit between a goal pursuit strategy (GPS) manipulation in the ad and consumers chronic regulatory focus increases the effectiveness of the advertisement, but the regulatory fit effect is moderated by temporal orientation (Kees, 2010). Exposure to the PSA had no discernible effects on HIV-related knowledge, but did affect perceptions. Compared with an unexposed control group, students exposed to the PSA estimated seeing more HIV- and AIDS-related PSAs and rated the usefulness of TV PSAs lower, at the same time were more likely to rate their chances of contracting HIV as low or none. The respondents expressed less desire to obtain more information. The use of an all-mnemonic phone number resulted in a threefold increase in recall of the CDC National AIDS Hotline phone number, but did not affect intentions to call. Overall, the results reaffirm the importance of deploying strategies that go beyond reliance on either a single PSA or TV PSAs alone to affect knowledge, perceptions, or intentions (Nowak, 1993). A study to judge effectiveness of PSAs found that it is necessary to conduct empirical research to determine the critical variables influencing a given behavior also there is a need to critically evaluate the potential effectiveness of a given PSA. As all PSAs might not be equally effective and some even might have negative effect. To be effective the PSA need to provide new information and perceived as realistic (Fishbein, 2002). Public service campaigns are often developed without prior assessment of target audience felt needs and perceptions; audience are not segmented into subgroups indicated by these characteristics, and message and material development proceeds without pretesting the effect of such factors as message clarity, appeals or presenters with target audience (Bratic, 1981). Although testing message in pre-finished form, the producer can identify and correct, potential weaknesses and corrections would be time and budget affordable. In absence of a standardized Health message testing service, effectiveness needs to be checked through post testing. Studies like this one can offer implications for theory, as well as for creators of public service advertising campaigns. North Coast Area Health Service (NCAHS) conducted a seven week television advertising campaign to raise community awareness of the availability of free adult pneumococcal vaccination and to increase coverage among North Coast residen ts. Effectiveness of the campaign was evaluated by examining vaccine ordering patterns of North Coast vaccination providers keeping previous year as a base. In the months during and immediately following the advertising campaign, a significantly higher proportion of vaccines were dispatched to North Coast immunization service providers (Wallace, 2008). An intervention approach using culturally sensitive mass media messages to enhance protective beliefs and behavior of African American adolescents at risk for HIV is suggested by Romer, 2009. This approach exploits the potential that mass media messages have, not only to reach a large segment of the adolescent population and thereby support normative change, but also to engage the most vulnerable segments of this audience to reduce HIV-associated risk behaviors. This study provides further evidence that if a media campaign achieves high exposure and is developed on the basis of careful formative research; it can be an effective HIV-pr evention tool for reaching high-risk youth within communities that need them the most. PSAs containing strong verbal claims are rated as more effective than those with weak claims. Arousing messages with weak claims are perceived as least effective. Surprisingly in this study increasing claim strength increased memory for negative but not for positive messages. It is suggested that the combination of intense emotional appeal and weak claims may be partially responsible for the boomerang effects in antidrug campaigns (Lang, 2008). In a study to investigate the consequences of using national celebrities, local celebrities and disaster victims as spokespersons in a public service radio announcement (PSA) soliciting contributions for victims of Hurricane Katrina, it was found that the hurricane victim was the most credible and believable spokesperson. The national celebrity, Ashlee Simpson, was the least credible and the least believable. The local celebrity was more credible and believ able than the national celebrity, but no more so than the hurricane victim (Toncar, 2007). No studies were found in Indian context regarding effectiveness of PSA. An attempt is being made to explore this area through this empirical study. Research Design Research Objective To Study the effectiveness of Public Service Awareness Campaigns in diseases such as Malaria , T.B. AIDS. Methodology The present investigations were descriptive in nature with survey being used as the major research approach. The study used survey method of obtaining information, which is based on the interrogation of respondents through a structured questionnaire. Scope of the study Being self-funded the study was confined to Ahmedabad city of India. The city is one of the most important urban centers of country and represents diversity of India. Sampling Plan The Population: The study is carried out in Ahmedabad city of India. The total urban population of city becomes population for the study. Sampling Unit: Sampling units for the study is individual. From the above population, all the respondents who have seen any of the selected advertisements for the study were defined as sampling unit for the purpose of the study. Sampling technique: Non probability convenience sampling was used. Care was taken to make the sample representative of the actual population. Size of the Sample: Respondents for the study were 150. Instrument for data collection For data collection a survey using a structured questionnaire was conducted. To Measure effectiveness a questionnaire consisting of open and close ended questions was used. The questionnaire included scale developed by-Leavitt, Clark. (1970). A Multidimensional Set of Rating Scales for Television Commercials, Journal of Applied Psychology, 54, 427-429, to judge effectiveness of advertisements apart from other open and close ended questions regarding use of celebrities and other executional aspects of the advertisements. The comprehensive scale gives effectiveness of Advertisements using Forty Five items with eight dimensions like Energetic, Amusing, Personal Relevance, Authoritative, sensual, Familiarity, Novel and Disliked. Results Recall of the advertisements Advertisement of AIDS was highest watched followed by TB and Malaria. Suitable Media Best suited media for creating awareness through PSAs was found to be Television followed by Print. Road shows or rally were not found to be very effective media for communicating health related social issues. Impact of Celebrity/ Religious leaders People strongly agreed to impact of Celebrity and Religious Leaders in creating awareness through PSAs (Mean 3.84). In terms of source credibility i.e. effectiveness of Celebrity endorsers in PSAs, Mean score for Attractiveness (4.50) was highest followed by Trustworthiness (3.93) and Expertise (3.61). It implies that popular celebrities are helpful in drawing attention of masses towards the campaign. Merely appearance in the advertisement increases the recall of the advertisement and thus increasing effectiveness of PSA. Useful Information Communicated by the campaign As evident from high mean score (3.37), people do believe that they gain useful information from the PSAs. Effectiveness of Advertisements To judge the effectiveness 45 item Levitts reaction profile was used. The scale has eight dimensions giving effectiveness of the advertisements. Responses were collected on a 5 point scale where 1 indicated does not fit and 5 indicated fits extremely well. The scores for last dimensions were reverse coded to judge overall effectiveness of the advertisements. As can be seen scores for personal relevance, familiarity and disliked (reverse coded) are higher. Thus it can be inferred that the respondents find advertisement to be meaningful and relevant as well as they have seen those advertisements many times indicating familiarity with the advertisements. The score for Disliked dimensions were high (reverse coded) indicating people liked the public service advertisements. TABLE 1: EFFECTIVENSS OF PUBLIC SERVICE ADVERTISEMENTS (LEVITTS REACTION PROFILE) Effectiveness of PSA Dimension Mean score TB Malaria AIDS Energetic 2.48 2.58 2.62 Amusing 2.52 2.43 2.46 Personal Relevance 3.43 3.36 3.46 Authoritative 2.74 2.73 2.85 Sensual 2.53 2.61 2.76 Familiarity 3.10 3.09 3.27 Novel 2.88 2.80 2.82 Disliked 3.65 3.61 3.60 Overall Mean 2.90 2.89 2.96 Factor Analysis: There are two preconditions for running factor analysis. They are measure of sampling adequacy should be greater than 0.5 and second being determinant value should be non zero. For all the factor models ran as mentioned in table 1, both these conditions are satisfied. TABLE 2: ALTERNATIVE FACTOR MODELS Scale Number of factors Factor Model Explained variation Number of factors TB 12 e>1 76% TB 08 Eight factors 66.7% Malaria 12 e>1 75.9% Malaria 08 Eight factors 65.5% Aids 12 e>1 76.11% Aids 08 Eight factors 65.5% TB By factor analysis, it is inferred that when we solve for eight factor solution, we are able to deduce eight factors like energetic, mix of amusing and novel, personal relevance, authoritative, sensual, familiarity disliked factors. When we solve for eigen value greater than one, we deduce 12 factors. The factor structure for eight factor solution is more clean compared to eigen value greater than one solution. But, it is less precise than provided by the scale. Malaria Factor analysis was conducted and eight factor solution had a better fit compared to eigen value greater than one solution. The factors deduced from eight factor solution are namely, mix of amusing and dislike, novel, sensual, authoritative, familiarity, energetic, personal relevance a mix of personal relevance authoritative dimensions. Aids Factor analysis was conducted and eight factor solution had a better fit compared to eigen value greater than one solution. The factors deduced from eight factor solution are namely, Mix of energetic, Sensual, Disliked Amusing, Energetic, Authoritative, Mix of familiarity Novel, Personal Relevance 1 Personal Relevance 2. Difference in perception of respondents of different demographic segments regarding effectiveness of public service advertisements As can be seen from table 3, we can infer that for disease TB, the difference in scores for amusing and personal relevance dimensions of Leavitts reaction profile scale for respondents across different income levels is statistically significant at 0.05 level of significance. Also, the difference in scores for energetic, amusing, authoritative, sensual, novel and disliked factors of the scale for respondents of different age brackets is statistically significant at 0.05 level of significance. The difference in scores on energetic, amusing and disliked dimensions of the scale is statistically significant for male and female respondents. Similarly from table 4, we can infer that for disease Malaria, the difference in scores for personal relevance dimension for respondents across different income levels is statistically significant at 0.05 level of significance. Also, for disease AIDS, the difference in scores for personal relevance, energetic, amusing, authoritative, sensual, novel and disliked factors for respondents of different income levels are statistically significant. The difference in scores on energetic, amusing, personal relevance, sensual, novel and disliked factors for respondents of different age brackets are statistically significant. Also, the difference in scores on energetic, amusing, personal relevance, novel and disliked dimensions for male and female respondents are statistically significant at 0.05 level of significance. TABLE 3: ANOVA RESULTS FOR DISEASE TB Between Groups Sum of Squares Df Mean Square F Sig. Income Levels Amusing 22.905 4 5.726 4.527 .002 Personal Relevance 4.313 4 1.078 3.216 .015 Age Levels Energetic 12.451 3 4.150 6.704 .000 Amusing 21.245 3 7.082 5.587 .001 Authoritative 5.178 3 1.726 3.488 .017 Sensual 9.145 3 3.048 5.708 .001 Novel 10.164 3 3.388 7.532 .000 Disliked 19.897 3 6.632 10.750 .000 Gender Energetic 3.169 1 3.169 4.706 .032 Amusing 12.539 1 12.539 9,578 0.002 Disliked 9.541 1 9.541 14.060 0.000 TABLE 4: ANOVA RESULTS FOR DISEASE MALARIA Between Groups Sum of Squares Df Mean Square F Sig. Income Levels Personal Relevance 5.501 4 1.375 3.511 .009 Age Levels Energetic 10.926 3 3.642 9.089 .000 Amusing 17.485 3 5.828 9.304 .000 Authoritative 4.245 3 1.415 3.850 .011 Sensual 9.945 3 3.315 5.810 .001 Novel 6.597 3 2.199 4.206 .007 Disliked 15.923 3 5.308 8.339 .000 Gender Between Groups Sum of squares Df Mean Square F Sig. Energetic 2.370 1 2.370 5.231 0.024 Amusing 3.968 1 3.968 5.594 0.019 Disliked 5.423 1 5.423 7.759 .006 TABLE 5: ANOVA RESULTS FOR DISEASE AIDS Between Groups Sum of Squares Df Mean Square F Sig. Income Levels Energetic 6.645 4 1.661 2.906 .024 Amusing 9.031 4 2.258 2.903 .024 Personal Relevance 7.443 4 1.861 5.770 .000 Novel 4.642 4 1.160 2.887 .025 Age Levels Energetic 7.310 3 2.437 4.327 .006 Amusing 9.007 3 3.002 3.886 .010 Personal Relevance 3.570 3 1.190 3.432 .019 Authoritative 5.125 3 1.708 4.178 .007 Sensual 11.302 3 3.767 3.062 .030 Novel 7.075 3 2.358 6.165 .001 Disliked 10.409 3 3.470 5.458 .001 Gender Energetic 4.605 1 4.605 8.024 .005 Amusing 6.750 1 6.750 8.682 .004 Personal Relevance 1.565 1 1.565 4.400 0.038 Novel 2.282 1 2.282 5.570 .020 Disliked 3.667 1 3.667 3.667 .021 Effectiveness in terms of preventive measures From the survey it was revealed that people have taken proper preventive measures after watching advertisement of public service campaigns. More than 94% respondents agreed to the fact. As per the survey people think AIDS is the most harmful diseases than T.B. and Malaria. From the survey it can conclude that most of the respondents (57%) have provided BCG Malaria vaccine to their child but still a good number of respondents are there who have yet not provide these vaccines to their child (43%). It shows that either these diseases are not considered to be as severe by the respondents or awareness for availability of vaccine for these two diseases is low. Majority of respondents (73% ) were found to be are aware of free government services that is run by government in their area for diseases like AIDS, T.B and Malaria. Discussion Recall for AIDS advertisement was highest followed by TB and Malaria. Celebrities were found to be effective in PSAs. Celebrities were found to be high in attractiveness and thus adding more credibility to the campaign. Respondents believed that they gained useful information from the public service campaigns. Television was found to be the most effective media for PSAs. Overall effectiveness of all PSAs was found to be high. As evident from the above findings it can be concluded that people have good exposure to the public service campaigns and find advertisements to be relevant. People liked the PSAs. Clear factor structure has not emerged as compared to the standardized scale. Some dimensions were not deduced in case of all three cases. Differences were found amongst different demographic segments of consumers regarding perception towards the advertisements, signifying importance of tailoring the advertisements for different demographic segments. From the survey it was revealed th at people have taken proper preventive measures after watching advertisement of public service campaigns. Most of the respondents have provided BCG Malaria vaccine to their child but still a good number of respondents are there who have yet not provide these vaccines to their child. It shows that either these diseases are not considered to be as severe by the respondents or awareness for availability of vaccine for these two diseases is low. Thus it is imperative for government to promote vaccination for the said ailments. Aware ness of free government services run by government in their area for diseases like AIDS, T.B and Malaria was found to be high. Limitations and Future Research Limitations associated with non probability sampling techniques go with this study also but due care was taken to make sample representative of the actual population. Further research can focus on lifestyle and personality factors of the respondents that might shape their perceptions towards the public service advertisements.

The Wife of Baths Tale :: Canterbury Tales, Chaucer

The wife's life with her first three husbands (lines 193-451) The wife of bath begins this section by giving an account of her first three marriages. She treats her first three marriages as one marriage; talking about how she used the same techniques to control her husbands and does not refer to individual people but a combination of all her first three husbands which she refers to as her husband. The wife begins, with a shockingly cynical statement, by informing her audience that her first three husbands were good, because they were rich and old and easily controlled. "The thre were goode men, and riche, and olde." This is very degrading to her husbands; she did not care about them at all and is more then willing to stand up in front of a crowd and degrade them. "How pitously a-night I made hem swinke!" Her degradation of her husbands continues as she goes on to tell her audience how easily she controlled them by forcing them to give her their worldly possessions, "And sith they hadde me yeven al hir lond." The wife then goes on to tell about how she used to cheat on her husbands and get away with it if anyone told by convincing them that the person who told them was crazy by getting her friends to convince them she didn't. "And take witnesse of hir owene maide." The wife was also able to get her husbands to buy her new clothes and make up and any item she wanted by taking ad vantage of their kind nature. She would tell them that she was not respected like her neighbour was because she has not got so many nice things. "I sitte at hoom, I have no thrifty clooth." The wife is very proud of her achievements at controlling her husbands and goes into great detail about how she makes up stories about her husbands getting drunk and insulting her. "Thou comest hoom as dronken as a mous, and prechest on thy bench, with ivel preef!" she also says they insult marriage to women in general, saying you cant marry a poor woman "To wedde a povre womman, for costage" and you cant marry rich women "And if that she be riche, of heigh parage, thane seistow that it it a tormentrie to soffre hire pride and hire malencolie." The wife also says that her husbands use petty arguments against her "Thow seist that dropping houses, and eek smoke, and chiding wives maken men to flee.

Rural Homelessness Essay -- Exploratory Essays Research Papers

Rural Homelessness As the Joad family lost its farm and hit the road in Steinbeck's classic, The Grapes of Wrath, so to did America lose its ability to plead ignorance to the problem of rural homelessness. Yet, as the troubles of the Great Depression, and two million homeless Americans, were eclipsed by a world at war, the issue of homelessness was once again placed on the back burner, and then taken off of the stove altogether (Davis 275). Although this problem has seldom been discussed in the sixty years since, rural homelessness is again on the rise and threatens to become the major problem facing rural America (Rural Homelessness). Less than ten miles from the intersection of Sprague and Division in downtown Spokane, the problem of rural homelessness in our own community is glaringly evident. At the intersection of Sullivan Road and Interstate 90, in the Spokane Valley, where drivers are momentarily slowed in their rush to get on with life, stands testament that not everyone is sharing in the American dream. With their worn out Levi's, old coats, and sometime mismatched shoes, the homeless work these corners for handouts like pigeons gathered around an old man on a park bench. These people don't ride out here on the number three bus from the STA Plaza, and they don't commute here in the Geos, Hondas, and Cadillacs that are constantly stopping and going with the changing of the lights. The people that ply these corners with their homemade cardboard "Please Help" signs, are here because this is the closest (and therefore most convenient) corner to where they sleep. A short walk along the rocky northern bank of the Spokane River, west of Sullivan, leads to a camp tucked among the ponderosa's in... ...ousing Assistance Council. Jan. 2001. 4 Apr. 2001.http://www.ruralhome.org/pubs/infoshts/rhomeles.htm Vissing, Yvonne. "Homeless Children: Addressing the Challenge in Rural Schools." ERIC Digest. Jan. 1999. 4 Apr. 2001. http://www.ael.org/eric/digests/edorc981.htm. Wilkinson, Todd. "How small-town America handles rural homelessness." Christian Science Monitor. 16 Mar. 1999. 5 Apr. 2001. http://www.csmonitor.com/durable/1999/03/16/fp2s2-csm.shtml Zimmerman, Julie. "Rural Poverty: Myths and Realities." Rural Development News. Volume 21. Number 1. Mar. 1997. 4 Apr. 2001 http://www.ag.iastate.edu/centers/rdev/newsletter/mar97/rural.poverty.html. Zimmerman, Julie. "Rural Poverty: Myths and Realities." Rural Development News. Volume 21. Number 2. June 1997. 4 Apr. 2001. http://www.ag.iastate.edu/centers/rdev/newsletter/june97/rural.poverty.html.

John Steinbecks East of Eden - The Character of Adam Trask :: East Eden Essays

The Character of Adam Trask in East of Eden In Webster's Encyclopedic Unabridged Dictionary of the English Language, the word love is defined as a profoundly tender, passionate affection for another person. Love can bring two people together but it can also have a person be rejected by another because of love. In the novel East of Eden by John Steinbeck, the main character, Adam Trask, confronts a feeling of love throughout the whole book but he either rejects the love of people who care about him or has his love rejected by the people that he cares about. When Adam was a young man in the beginning of the novel, his father, Cyrus Trask loved him but Adam did not love him back and when Adam went into the army he did not come back home until his father's death. Later on in the story Adam really loved his wife, Cathy, but she didn't love him back and so when she tried to leave him and he would not let her, she shot him. Even though Adam survived he was demoralized for most of his life because he still loved her. Through Adam's ex periences of love in the novel, John Steinbeck shows that Adam Trask has an inability to handle love. When he first appears in the novel, Adam Trask is a young man who is not loved by his brother or mother but only by his father. Cyrus had punished Adam before and had tried to teach him to be a soldier and so Adam hated him for that and when Cyrus told him he loved him, Adam did not accept his love. Cyrus tells Adam, "I think you're a weakling who will never amount to a dog turd. Does that answer your question? I love you better. I always have. This may be a bad thing to tell you, but it's true. I love you better. Else why would I have given myself the trouble of hurting you?" (Steinbeck 28). Cyrus is telling Adam that he has always loved him and that the only reason that he punished him is because he loved him. He wants Adam to go into the army because he knows that Adam would be courageous and since Cyrus was in the army, he wants to pass on the legacy. When Adam came home from his discharge, his brother and him were talking about their father and Adam told him the truth.

Regard to the play Essay

The 1st act of any play is more than just an exposition. It shows the strengths and weaknesses of the playwright clearly. Comment on this in regard to the play. There are certain aspects the playwright has to keep in mind when he writes the first act of his play. Usually, most of the first acts of plays are as already mentioned, expositions. The writer introduces the protagonist, the antagonist, the setting of the time. Moreover, not only does he set the mood for the rest of the play but he also starts building some dramatic tension between his characters and starts giving us hints about what is going to happen next. But apart from all this, the most difficult thing the playwright has to do in the first act is make it interesting and gripping. This is extremely significant because if the first act of the play is not gripping enough, the readers won’t like to go ahead. This situation is just like how, on a bad foundation, any kind of structure won’t last long and so nothing can be built upon it. So, the dramatist is supposed to catch the reader’s interest and then retain it too, making the first act almost like a mini play in itself. To make the first act attention-grabbing, the dramatist must introduce a conflict – between characters, between situations – and thus build the dramatic tension of the play. This is similar to what Ibsen did in doll’s house. He not only made the readers meet Nora Helmer but he also showed changes in her character in the first act itself. At the outset, Nora was very frivolous and perky but later in the act, she seemed a much more mature woman than one perceived before. Thus Ibsen, as a writer, managed to take his readers through all the subtle nuances in Nora’s character. This came out as Ibsen’s major strength. He showed Nora as silly yet sensible, lying yet truthful, making her character a complete rollercoaster for the readers in the first act itself. The other characters he introduced were torvald and mrs. linde. Where both these characters came to be very linear, Mrs. Linde’s role was more than just Nora’s friend. She was a foil which Ibsen introduced to make us understand Nora in a much better way by contrasting her with Mrs. Linde. Therefore, as one can see, Ibsen took so much pain, put in so much effort, only for making us relate to Nora in as much depth as possible. This was also Ibsen’s another strength which came up in the first act. It was his asset because he knew that his protagonist is unconventional since she is going to walk out on her husband and children for something which people in that time thought to be very trivial – self-respect. Therefore, he recognized the fact that he must do something to make his readers relate with Nora’s emotions and so he used the techniques of contrasting – by using mrs. linde as foil, foreshadowing – by hinting in Nora’s dialogues about what is going to happen later in the play and showing and telling and thus created such an act where if nothing, at least he left the readers curious about Nora and wanting to know more about her and about what happened to her, if not curious about the rest of the play.

Different Structure of Organisation and Culture Essay

Section 1 Understanding the relationship between organisational structure and culture You will need to: compare and contrast different organisational structures and culture Here you need to briefly describe the different types of organisational structure, and what different types/formats of culture can be found in organisations, and then compare and contrast them – what causes/creates each type, and positive factors / negative factors of each. explain how the relationship between an organisation’s structure and culture can impact on the performance of the business Then discuss (separately) how the structure and culture can affect the business performance – by comparing at least two different types (from those you have described) – for example, you could discuss the differences between a small, growing, owner-managed, flat-structured, entrepreneurial business, with a large, established, bureaucratic, organisation such as a local authority/municipality. Then compare for example, how quickly changes can be made – very fast, immediate decisions made informally in the one – very slow, only after many meetings, reports, evaluations, etc in the other. discuss the factors which influence individual behaviour at work For this – list and discuss the factors which can influence the way individuals behave – for example: management/leadership style, pay and reward mechanisms, levels of employee involvement in decision making, and so on. Section 2 Understanding the different approaches to management and leadership You will need to: compare the effectiveness of different leadership styles in different organisations You need to give a brief description of the recognised, established styles, but then select 2 different styles, as applied in 2 different types of organisation (for example in a large international company, compared to a local municipality/council, and discuss how effective  each is in. Unit 3: Organisations and Behaviour explain how organisational theory underpins the practice of management You need to list the main theories/models (that you have been studying and researching) and then discuss how each one helps – supports – assists managers to effectively plan / organise / manage / control / respond to problems. Simple examples are – knowledge (theories/models) of how individuals are likely to respond to a major change – this can help managers to introduce/implement the change in a certain way – to avoid some of the more negative responses that might occur ~ and the models/theories on structure – and how it can influence the culture/behaviour of the organisation and its people. evaluate the different approaches to management used by different organisations This is about comparing how, at the corporate – whole organisation-level – two different organisations apply management theory and theories of organisation, to the way they run their businesses. You need to select 2 very different organisations and, as it asks, compare their approaches. A simple comparison, as an example, would be to look at the Army – and its approach to managing its ordinary soldiers, officers, teams & individuals – and compare this with a college or university – and its approach to managing students, teachers & lecturers. Section 3 Understanding the ways of using motivational theories in organisations You will need to: ï‚ · discuss the impact that different leadership styles may have on motivation in organisations in periods of change You need to give a brief description of the recognised leadership styles, but then discuss in detail how each one can positively or negatively affect the motivation and morale levels of individuals and teams, in periods  of change – that is, in the planning, implementation and aftermath of a major change.   compare the application of different motivational theories within the workplace You need to give a brief description of each, but then discuss in detail how they are (if they are) applied in the workplace, then move on to discuss how motivational theory relates to the way people are expected to manage today. evaluate the usefulness of a motivation theory for Managers Here you need to – briefly – list an describe motivational theories, then select one and use that to give your view of how an understanding and application of that motivation theory can assist/support managers in their activities. Unit 3: Organisations and Behaviour Section 4 Understanding the mechanisms for developing effective teamwork in organisations You will need to: explain the nature of groups and group behaviour within Organisations Here you need to – briefly – explain the different group/team formal and informal structures, objectives, life-cycle stages, types of dynamics, and how all of these factors can affect the behaviour of groups/teams in the workplace. discuss factors that may promote or inhibit the development of effective teamwork in organisations This needs to be looked at in a broad, lateral, way – for example, the structure of an organisation can affect team interactions/communications with other, important, teams – the management/leadership style of the line managers and specialist managers can be very damaging or positive – a â€Å"blame† culture is very damaging, the amount of individual personal development, progression opportunities, appraisal formats, can also have an effect â €“ and team development / access to technology / access to support from other teams/specialists, can be factors. evaluate the impact of technology on team functioning within a given organisation Here you need to select a particular (â€Å"given†) organisation, or type of organisation (not simply â€Å"in general†), and then describe and evaluate the positive and negative impacts (or potential impacts) of current and emerging technologies (eg. computers, mobile phones, ipads, social media such as facebook,  linkedin, video conferencing, the internet, intranets, laptops, remote working, email) on the way a team functions/operates.