Three Tier Architecture Is A Client Server Information Technology Essay

Three Tier Architecture Is A Client Server Information Technology Essay In software engineering, three-tier architecture is a client-server architecture which consists of three layer; presentation layer, functional process logic layer and data layer and is develop and maintain as different module. This architecture is developed by Jon J.Donovan in Open Environment Corporation(OEC), a tools company the founded in Cambridge, Massachusetts. By dividing application into tiers or layers, developers only have to modify or add a specific logic into the desired layer, rather than rewrite the whole application. This architecture will allows developer to create a more flexible, reusable and maintainable application. This kind of Three-tier layer can also be known as multi-tier architecture or n-tier architecture. Example when user wants to change the text colour from black to red, only the presentation layer will be affected. A common example of three tier architecture is ATM (Automated Teller Machine) or Cash Machine. The GUI (Graphical User Interface) where we select services is the presentation layer for ATM. When selecting one of the services that are displayed on the screen, designated event for the services will be invoked. This common set of behaviour is designed in the functional process logic layer. When requesting information such as checking the balance in our bank account, ATM will get the data from the database or application server. This will be the data layer. Presentation Layer or can also be known as presentation tier, a layer where the presentation or user interface of an application is designed or displayed. In other word, this is the layer which will display all the information that is needed or requested by the user. Presentation layer is the top most layers in the three-tier architecture. Besides displaying information that is needed by user, this layer will also be used to communicate between other layers by user. For example in Window OS (Operating System), program icon is displayed to allow user to click on it to open the clicked program. Presentation layer is also part of security where only the needed information will be displayed while other sensitive information will be kept. For example, stock department will need to be able to view and edit the product stock while sales department only need to be able to view the stock that is available. The presentation layer for Al-Seraj Hire Firm will consist of multiple types. This is because Al-Seraj Hire Firm has different employees that are specialise in different type of aspect of business services in the hire firm. Some employees will only need to display certain information while other may have more or less information. For example in Al-Seraj Hire Firm; purchasing, customer account, sales and marketing will have their own presentation layer. Functional process logic Layer Functional process logic Layer is the middle layer in the three-tier architecture. It can also be known business or data access tier, a layer where logic and calculation is taken place. In other word, the business function or business flow will design in this layer. Functional process logic layer contain the code or function to control the application functionality and also the application business flow. Besides that, it also contains the business logic of the company. Functional process logic Layer is separated from presentation layer and data layer is to protect the confidentiality and integrity of business flow of a company. Besides that, function is shared by different users. This enables the system to have a consistent and centralized function that can be used by different users. For example, the function or logic to view the stock that is available in the company that is viewed by the stock department the same as what is seen by the sales department. Other than that, by separating the functional process logic layer, it will enable the administrator or person in charge of the system to easily add in or modify the logic in the system without affecting the other layer. The functional process logic layer in Al-Seraj Hire Firm will contain the function to indicate whether the customer is a private customer or a business customer. This is because private customer and business customer has their own business logic. Examples of business logic are hiring equipment for private customer is restricted within five miles radius while business customer doesnà ¢Ã¢â€š ¬Ã¢â€ž ¢t have this restriction. Besides that, business customer will have a 24-hours customer services to replace the faulty equipment while private customer will need to bring in the faulty equipment to replace to working equipment or get a full refund if the equipment is not available. Data Layer Data Layer or can also be known as data tier, is a layer where all the data which is inserted by the user is saved. In other word, all information that is entered by the user will be saved in this layer. Data layer will be responsible to provide the data that is requested from the user. Besides that data can be shared by different users. By doing this, data integrity can be achieved and providing accurate data that is requested by users. This is because the data is saved in a single database which allow different user to get access and request for the data. Besides that, by separating data layer, this will improves the scalability and performance of the system. The data layer in Al-Seraj Hire Firm will contain the price of the equipment and also the delivery time that is offered by the suppliers. Besides that, it also contains the customer account and also the account packages that are provided by the hire firm. The five most important user group for Al-Seraj Hire Firm System are Purchasing, Customer Account, Stock Management, Sales and Marketing and Administrator. Administrator Administrator is a user group which have the most privileges than any other user group in the system. This is because administrator is a user group that is designed to control or use the full function of the system. Besides that, they also have the privilege to change sensitive data such as the price or discount value for each type of membership account. This user group is used by the owner of Al-Seraj Hire Firm or the person-in-charge of the system. There are three quality requirements for Administrator user group. The first quality requirements are security requirement. Security requirement is the requirement for the user to be authenticated and authorize as administrator user group. In this user group, the user of the system will need to be authenticated before user is allowed to be authorized as an administrator. The second quality requirements are modifiability requirement. Modifiability is the requirement for the user to be able to add, modify or delete any data in the database. In this user group, the user of the system will be able to add, modify or delete data in the system. Examples of data in database are discount value for silver membership, gold membership and diamond membership. The third and last quality requirements are testability requirement. Testability requirement is the requirement for the user to be able to test the whole system with ease. In this user group, user will have the full function that is provided in the system. This also includes other user group function such as stock management and customer account information. Administrator user group is the top user group in Al-Seraj Hire Firm. This is because any changes that are made by administrator user group, other user group will also be affected. For example, discount value for silver membership which are currently 10%, has been changed to 15%, all user group will have to follow the new discount value. Customer Account Customer Account user group is a user group which is responsible for managing customer. In other word, this user group is designed to manage all the type of customer who makes transaction with Al-Seraj Hire Firm. Besides that, this user group also responsible to modify or update customer information and also provide customer services to the customers. There are two quality requirements for Customer Account user group. The first quality requirement is modifiability. User in this user group will need to be able to change the customer account information as accurate as possible to maintain the productivity of the company. For example, company X has changed their address; the user will need to change the address to the new address to allow other employee to deliver the goods to the destination. The second and last quality requirement is performance. Performance requirement is the requirement for the user to be able to access or display the desired data in a less amount of work. In this user group, user will need to use the system to search out the suitable customer account in a less amount of time. Customer account user group is the low level user group in Al-Seraj Hire Firm. This is because all customer details will need to be added into customer account database. As for the data of the customer account, user from the same level will need to take reference to decide which type of customer are they dealing with. For example, a customer has called in and reported that one of their tool has been broke, the user will need to check the customer details to identify whether the customer is a business customer or a private customer. Sales and Marketing Sales and Marketing user group is a user group which is responsible for doing sales transaction with the customer. In other word, this user group is designed to record any transaction that is made with customer into the database via Al-Seraj Hire Firm system. Besides that, this user group will also keep track or produce a financial report according to the sales transaction that has been made in a period of time. There are three quality requirements for sales and marketing user group. The first requirement is performance. Performance is important for this user group because this is where the income of the Al-Seraj Hire Firm came from. User in this user group will need to have the speed and efficiency to search for tool that is available in time and also the price for it. Besides that, they also need to identify whether it is an existing customer and which type of customer are they in Al-Seraj Hire Firm. For example, two users from this user group will be able to use the system simultaneously to search for customer information. The second quality requirement is availability requirement. Availability requirement is important for this user group is because sales of Al-Seraj Hire Firm need to be available during working period. In other word, the system will need to be available when it is needed. For example, maintenance or patch of the system can only be done when there are no people that are using the system to prevent disruption of the sales flow. The third quality requirement is usability. The information that retrieves by the user from the system can be used or not. In other word, the user will need retrieves accurate information from the system. Sales and marketing user group is the low level user group in Al-Seraj Hire Firm. This is because user will need to be able to access into the stock management user group information and customer account user group information. This is because they need to identify whether the customer is a private or business customer and is the tool available and what is the price for it. Stock Management Stock Management user group is a user group which is responsible for managing stock in Al-Seraj Hire Firm. In other word, this user group is designed to maintain the availability of tool stock in Al-Seraj Hire Firm. There are two quality requirements for stock management user group. The first quality requirement is usability. The user of this user group will need the accurate information of the stock that is available in Al-Seraj Hire Firm. In other word, user need to get the real number of stock that is available to decide to restock or not. This is because other user group such as sales and marketing will also be able to change the value of the stock in the stock database. The second quality requirement is modifiability. User will need to be able to change the value or number of stock in the database through the system. In other word, user will add or modify the number of stock in the database via the system that is designed. Stock management user group is the low level user group in Al-Seraj Hire Firm. This is because user in this user group will need to be able to check for the number of stock that is available and restock it if it is not enough. Purchasing Purchasing user group is a user group which is responsible for purchasing new equipment brands based on Al-Seraj Hire Firm equipment categories. In other word, this user group is designed to purchase new equipment brands for the stock management user group. There is one quality requirement for purchasing user group. The quality requirement is modifiability. The user of this user group will need to be able to add in new equipment information into the database. For example, brand X information will be saved into the stock database. Purchasing user group is the low level user group in Al-Seraj Hire Firm. This is because user in this user group will need to be able to add in new equipment in the stock database. Limitation There are three limitations or design flaw in Al-Seraj Hire Firm system that is designed. The first limitation is only five user group can use the system. This is because the system is designed to be able to allow only five user groups to be using this system. The second limitation is online ordering transactions are not available. This is because the system is not designed to be to have a shopping cart. The third limitation is system doesnà ¢Ã¢â€š ¬Ã¢â€ž ¢t allow add in new membership categories. This is because the system is not design to allow user to add in new membership categories. The limitation can be changed in the future by adding new function in the system. Parallel Changeover Changeover is a method that is used to implement or install the system into an existing or new server. There are four types of changeover; direct changeover, parallel changeover, pilot changeover and phases changeover. The changeover method that can fulfil the requirement of Al-Seraj Hire Firm is parallel changeover. Less expensive. Lower risk of error or failures. The first part is stock management module and purchasing module. The second last part is customer account and sales and marketing. In the period of implementation, user acceptance test is given to check whether the system fulfil their requirement. Training is given if the system is accepted by the user.

Human Memory How reliable is Eyewitness Testimony

Human Memory How reliable is Eyewitness Testimony This essays attempts to reach a conclusion regarding eyewitness testimonies and the extent of its reliability. This was done by identifying factors in three different processes stages. The acquisition stage is the period where the witness experiences the event. The retention stage is the period between the time the event ends and the time the witness are asked for a recount or questioned about the event. The retrieval stage is the period where the witness is providing information from their recall. During the acquisition stage, research regarding exposure time, estimation of factors concerning the event (for example, time), violence of the event, weapon focus and witness stress was analysed. During the retention stage, research regarding post-event information, introduction of conflicting information and introduction of misleading information was analysed. During the retrieval stage, research regarding method of questioning, leading questions and a case study of an actual event was analysed. Experiments and case studies regarding these factors were then evaluated to weigh the impact that it had on eyewitness testimony. In conclusion, it was found that experiments regarding eyewitness testimony hold little evidence to support its reliability but there are also some findings that dispute this. Thus, it was concluded that it is reliable only to a small extent though it can be highly accurate under certain conditions. Applications of this conclusion includes jurors being more aware of the factors regarding eyewitness testimony and taking into account when deciding on a verdict especially if the main evidence is based solely on eyewitness recounts. Eyewitness testimony is usually a verbal account given by an individual who has experienced an event, typically of a crime. Eyewitness testimony relies heavily on the capability of the individuals to accurately recount the event. In a trial, the jury is most often persuaded due to the statement(s) of the witnesses. Also, in cases where little material evidence can be collected, eyewitnesses are the focus for reaching a verdict. It has been argued that because testimonies are largely based on fallible memory which can be influenced by a variety of factors, it should not be depended upon. The contention of this essay is to identify and evaluate the extent of accuracy of this claim by identifying and evaluating factors that affect memory and by reviewing experiments and case studies to reach a conclusion on this matter. Memory and thus eye-witness reliability has become an issue of importance due to the high percentage of errors in identifying and prosecuting accused individuals. Thus, the reliability of eyewitness testimonies and impact on trials should be reviewed. Memory is defined as a kind of repository in which facts (information) may be retained over some period of time (Loftus, 1979). According to the Atkinson and Shiffrin model of memory storage (1971), memory is made up of three different types of information stores, each with different duration, capacity and function. The first is Sensory Memory. This type of store lasts for the spilt second when individuals collect information from their sensory systems and preserves information in its original sensory form. The sense organs are limited in their ability to store information about the world in an unprocessed way for more than a second. Thus, information is filtered through or selected by attention for further memory processing into the next type of memory store. This process of experiencing and filtering information is called acquisition. The next memory store is Short-term memory allows individuals to retain information long enough to be used and lasts approximately between 15 to 30 s econds. Miller (1956, cited in Weiten, 2005) proposed that Short-term Memory had a capacity of about 7 chunks of information. If certain actions are carried out, the information will be transferred to the last type of memory store, Long-term Memory. Long-term Memory provides retention of information which can last between minutes to a lifetime and has a limitless capacity. The process of information deposited in the short-term and long-term memory store is called retention. Information is constantly being transferred between these stores. When witnesses are asked to give recount of what they witnessed, information is taken from the long-term memory store and this process is called retrieval. Events during these three processes may affect the quality of the eyewitness testimony. During the acquisition process information may not have been perceived in the first place, information may be forgotten or interfered during the retention process or information may be inaccessible during questioning or during the retrieval process. Analysis of Factors that may affect Eye-witness Testimony during the Acquisition Process During the acquisition process, there are a number of factors that can affect an eyewitness report of an event such as exposure time or stress. This can be divided into event factors and witness factors. This section of the essay will evaluate the effect of these factors on the reliability of eyewitness testimony. Exposure time to the event or object of focus is an event factor. Laughery et al (1971, cited in Loftus, 1979) tested subjects on their recall based on the exposure time to a picture, showed one at a time of different positions of a human face. Two Caucasian male target faces were used, one with fair-colored hair and complexion with glasses and another with a darker-colored hair and complexion without glasses. The independent variable is the time the subjects viewed the pictures, which ranged from ten seconds to thirty-two seconds. The subjects were them asked, approximately eight minutes after exposure to identify the target within a series of 150 slides of human faces. The dependant variable is the accuracy of the subjects recall. Fifty-eight percentof the subjects who viewed the pictures for thirty-two seconds correctly identified the target but only forty-seven percent of the subjects who viewed the pictures for ten seconds correctly identified the target. This suggests that the more time a witness has to view the target, the more accurate their recall will be. This research is significant as it is very scientific and precisely tested a specific variable that affects memory and recall. Although this is so, it was also conducted in an artificial environment and thus, has low ecological validity. The research may also contain cultural and gender bias as it only tested for Caucasian males as the target. Thus, its application to targets of different cultures or gender is questionable. Estimating factors such as time, speed or distance is often asked of eyewitnesses. This involves perceiving the event and accurately inferring information from it. Marshalls (1966, cited in Loftus, 1979) experiment tested subjects estimation of time. Four hundred and ninety-one subjects watched a forty-two second film and a week after they had given their written and oral reports of the event, they were questioned as to the duration of the event. On average, subjects gave an estimate of about ninety seconds. The results show that witnesses can inaccurately estimate certain factors of an event. Although the results are significant, the study was conducted in a controlled environment which gives it little ecological validity. To further assess the accuracy of this study, an additional study that can be considered is Buckhout et al. (1975, cited in Loftus, 1979)s study on the effects if eyewitness testimony in a real situation by staging an attack where a student attacked a professor in front of 141 witnesses. The attack lasted for thirty-four seconds but when interviewed later on, the average estimate of the duration of the event was eighty-one seconds, almost twice the actual time. This study supports Marshalls study which shows that there is a tendency for witnesses to overestimate the duration in an event. This is significant in most cases, especially for cases of self-defense where the time between the attack and the retaliation is very significant in the categorization of the action. Another event factor is the violence of the event. A research done by Clifford and Scott (1978, cited in Loftus, 1979) investigated the ability of eyewitnesses to perceive violent and non-violent events. Forty-eight subjects with equal number of men and women watched either one of two tapes. In the non-violent version, the characters were involved in a verbal exchange and weak restraining movements. In the violent version, one of the characters physically assaults another character. In an effort to be even, the start and end of the tapes were manipulated to be identical. It was found that regardless of gender, the level of recall is significantly lower for those who viewed the more violent tape. It is inferred that this is due to the greater amount of stress that is produced in response to the violent event. This shows that eyewitness testimony of a violent event should be considered with the possibility of a higher rate of inaccuracy. Though the results are significant due to the hi gh reliability of the scientific method used, it also lacks ecological validity as it was conducted in an artificial environment where witnesses do not actually experience the event. An event factor that is linked to the witness factor, stress, is weapon focus. Easterbrook (1959) found that under high stress, individuals tend to concentrate more on a few features of their environment and less attention to other features. Weapon focus is where a crime victim is faced with an assailant who is brandishing a weapon. This rises the stress level of the crime victim and thus, they will only concentrate on a few features, mainly the weapon and will have trouble recollecting other factors such as the assailants features. Loftus et al (1987) tested this with an experiment where thirty-six students were showed a series of slides which showed one of two scenarios at a fast food restaurant. Half the subjects saw a customer pointing a gun at the cashier while the other half, the control group saw a customer handing the cashier a check. A part of the experiment tested the memory of the students based on a series of seven questions on the customer. It was found that the level of accuracy of the weapon group was fifty-six percent while the level of accuracy for the control group was sixty-seven percent. As the results show that the accuracy level of the weapon group is lower than the control group, this is highly significant in showing that eye-witnesses acquisition process might be seriously hampered by the presence of a weapon. The results of the experiment are highly valid as it was conducted in a controlled environment which allowed a direct cause and effect outcome. While this is so, the participants did not experience the event and thus their response may be different to an actual witness which means that the experiment lacks ecological validity. During an event, stress is a witness factor that should be taken into account. This refers to the level of stress or fear that a witness experiences which may influence their perception during the acquisition process of the event. A simulated case study done by Berkun (1962, cited in Loftus, 1979) placed army recruits in a stressful situation. They were isolated with the exception of a telephone link. Then, they were told that they were in danger to induce anxiety and were required to repair a broken radio by following a series of complicated instructions. It was found that the high level of anxiety impaired performance of the subjects. As this case study was conducted during a period of different ethical standards than today, there are ethical implications to be considered. Nevertheless, the results of this case study significantly support the Yerkes-Dodson law (1908, cited in Green) which states that emotional arousal facilitates learning and performance up to a point after which t here is a decrement. This can be applied to eyewitnesses who experience stress. Their senses may be stimulated but after a point, their acquisition process will be negatively affected. Although this is so, this case study has only looked at male soldiers, thus when applied to the general population, it lacks ecological validity. Analysis of Factors that may affect Eye-witness Testimony during the Retention Process Eye-witnesses are being tested on their retention of information from their Long-term Memory. Because retained information and thus, memory is being transferred between memory stores, it is possible that it can be influenced, enhanced or even distorted during or in between transfers. This section of the essay will focus on the numerous researches that have been carried out to investigate the accuracy of this or the extent of the influence that may occur. After an event occurs, sometimes witnesses discuss what they saw with each other and the information that is exchanged can result in an enhancement of memory in the form of modification or addition. An experiment was conducted by Loftus (1975) on one hundred and fifty participants. They were showed a film of a car crash where a car failed to stop at a stop sign and turned right to enter traffic, causing a five-car collision. After the film which lasted for less than a minute, participants were asked a series of ten questions. Half of the participants were asked about the stop sign in the first question while the other half were asked about the right turn. All other questions were the same. The independent variable here is the first question and the dependant variable is the last question which asked participants if they remembered seeing a stop sign. Loftus found that there was a higher percentage of participants who recalled seeing a stop sign if the first question related to a stop sign than the control group, fifty-three percent and thirty-five percent respectively. This shows that by mentioning an object, there is a higher chance of it being recalled. The results are highly significant as it was calculated using precise results with a specific variable tested. It can be argued that the experiment lacks ecological validity as it was conducted in an artificial environment but this allowed a specific variable to be tested which would have been impossible with a case study. As demonstrated by this experiment, eye-witnesses memory may be influenced by post-event information that they receive and thus, the more information that the witness is exposed to after the event, the higher the chance that their memory might be compromised. A modification to the previous variable is the question as to what happens when a witness learns new information which is different from what they experienced. Loftus (1975) conducted an experiment where forty participants were shown a three-minute video which involved a group of eight demonstrators noisily interrupting a lecture. The participants then had to answer a series of twenty questions. All the questions for the participants were identical except for one. Half of the participants were asked, Was the leader of the twelve demonstrators who entered the classroom a male? and the other half were asked, Was the leader of the four demonstrators who entered the classroom a male? All questions had to be answered with a yes or no. A week later, participants had to answer another set of questions. The critical question was How many demonstrators did you see enter the classroom? It was found that participants who previously answered the question with the word twelve reported an average of 8.9 demonstrators while the other half reported an average of 6.4 demonstrators. It can be argued that this experiment lacks ecological validity as it was conducted in an artificial environment and that participants only viewed the event and did not actually witness it. The results may not be fully applicable to the general population. Although this is so, the controlled environment showed a direct cause and effect of a specific variable. The results of this experiment can be applied to eye-witness testimony where witnesses may be mislead in their testimony as their memory might be compromised by the introduction of conflicting information. Similar to the experiment above is an experiment conducted by Loftus and Zanni (1975, cited in Hill, 1998) which was a modification of the original Loftus and Palmer research. The aim of the experiment was to investigate the effect of adding post event information on memory. Participants were shown a film of a car accident after which they had to answer a series of questions. Half of the participants were required to answer, Did you see the broken headlight which implied that there was a broken headlight while the other half were asked, Did you see a broken headlight which only required participants to recall if it was there. It was found that half of the participants, who were asked using the word the, incorrectly reported seeing a broken headlight. As most of the other variables were controlled in the experiment, and only a specific variable was changed, the results signify that memory can be modified by post event information. It can be argued that the participants did not experie nce the incident and thus the experiment lacks ecological validity when applied to actual witnesses but as a specific variable was examined, it can be concluded that the cause and effect was to a large extent connected. This experiment shows that eyewitnesses may be influenced by post event information which may negatively affect their account. McCloskey and Zaragaza (1985) also conducted experiments concerning the effect of misleading post event information on participants. After watching a series of slides depicting an event, participants received a narrative of the event. Participants in the mislead condition will receive a narration with receive the narrative with misleading information about a detail of the event, a hammer was referred to as a screwdriver instead while the control group werent provided details of the specific event. Participants then had to answer a series of questions about the event. The critical question concerning the tool had the original item as an option (hammer) and a new item (wrench). It was found that accuracy for the control group was seventy-five percent and seventy-two percent for the mislead condition group. The fact that there was little difference between the two groups points to the idea that misleading post event information does not distort memory of an event. This experiment suppor ts the validity of eyewitness testimony and due to the controlled setting; the results are highly valid though it lacks ecological validity. Analysis of Factors that may affect Eye-witness Testimony during the Retrieval Process Most evidence from eyewitnesses are a result of their accounts of the event. This involves the retrieval process of information from their long term memory store. This section of the essay aims to analyse and evaluate research conducted in relation to the techniques of retrieving information from eyewitnesses such as question wording or method of questioning. This is to evaluate the extent of influence of such techniques on the reliability of eyewitness accounts and in relation, memory. The method of questioning during the retrieval process plays an important role in the accuracy of eye-witness testimony as investigated by Lipton (1977, cited in Wells, 1978). Lipton conducted an experiment where participants watched a film of a murder in a courtroom setting. He found that unstructured testimony which allowed free recall resulted in ninety-one percent accuracy. This is a significant value as compared to other types of questioning such as open ended questions with eighty-three percent accuracy, leading questions with seventy-two percent accuracy and multiple choice questions with fifty-six percent accuracy. These results show that the type of questioning that the witness is subjected to affects the accuracy of their recount. When applied to trial testimonies, jurors should take into account the type of questioning to predict or get an idea of the level of accuracy of the testimony. Though conclusive to a certain extent, the experiment lacks ecological validity as the participants did not actually experience the event, merely perceive it but as it is a controlled environment, the reliability of the cause and effect factors is high. Loftus and Palmer (1974 cited in Hill, 1998) carried out an experiment to investigate the effect of leading questions on the accuracy of participants in recalling a car crash. Fourty-five participants were separated into seven groups and each group watched a video of traffic accidents. The videos lasted from five to thirty seconds. After watching the video, participants had to give an account of what they had just seen. The independent variable is the question About how fast were the cars going when they hit each other?. The word hit is replaced with the words smashed, contacted, bumped and collided for different groups. The participants answer as to the estimate of the cars speed is the dependant variable. Loftus and Palmer found that the mean estimate of speed for more aggressive words such as smashed is higher than less aggressive words such as contacted. The results are highly significant, p Contending the results of this experiment is Yuille and Cutshalls (1986) case study of a real life event. 13 participants were interviewed using Loftus and Palmers (1974 cited in Hill, 1998) technique in their recall four to five months after witnessing an attempted robbery in daylight where one individual was killed and another, seriously wounded. It was found that there was a very high level of similarity between the accounts given by the witnesses, the accounts did not alter in response to leading questions and that the witnesses were able to recall the event in detail. Additionally, accounts of those who were more distressed had a higher accuracy level. These results are different to Loftus and Palmer (1974 cited in Hill, 1998). The eye witnesses did not alter their accounts greatly in response to leading questions. As this is a case study, it holds high ecological validity unlike laboratory experiments. Although this may be true, Yuille and Cutshalls case study was of an event t hat was relatively traumatic event and was viewed in ideal conditions. Most incidents do not mirror this setting. Also, it was an investigation of only one case study. Hence, the application of these findings is debatable when applied to general eye witness testimonies. Conclusion This essay evaluated the extent of accuracy of the claim that eyewitness testimony should not be depended upon. This was done by focusing on the different factors that can affect human memory, and in relation, eyewitness testimony as it is fundamentally based on memory. Experiments and case studies related to factors in three different memory stages were identified and evaluated. Research concerning the acquisition process such as exposure time, estimation of factors concerning the event, for example, time, violence of the event, weapon focus and witness stress level during the event was analysed. Results point to a correlation of high levels of inaccuracy when more traumatic factors are included in the event. This is also reflected in research concerning the retention process and the retrieval process although there is some evidence that supports the reliability of eyewitness testimony. Overall analysis criticised the low ecological validity of controlled experiments but also supported the high level of validity that comes with it as it essentially provides a cause and effect relationship between specific variables tested. Case studies were found to be very specific with regards to certain factors, which leads to a debate about their general application. Since experiments are only replications of real-life events, it cant be fully taken as the actual process . This may have some influence on the results obtained as it can be argued that the participants are not really experiencing the event, thus essential factors like, atmosphere, or even interest in the event may be compromised. In this manner, results of case studies hold a higher level of reliability. As indicated by the numerous researches on different factors during the process of collecting, processing and retrieving information from memory, eye witness testimony is reliable only to a small extent. Under such fallibility, it can be questioned if eyewitness testimony should be relied on at all. Though eyewitness testimony has been proved accurate in a number of researches, the amount of investigations concluding on the fact that it is highly imperfect far outweighs it. Though a large number of researches do not support the reliability of eyewitness testimony, there is also evidence to support it like Yuille and Cutshalls (1986) case study. This suggests that although eyewitness testimony can be unreliable, under certain conditions, it is highly accurate. Implications for application of the analysis in this essay could include jurors being more wary of eyewitness testimony and the conditions relating to it when deciding upon a verdict. Further research could include more case studies to increase the ecological validity of the theories produced by experiments analysed in this essay. References Atkinson, R. C. Shriffin, R. M. (1971), The Control Processes of Short-term Memory, Stanford, California, Stanford University Easterbrook J. A. (1959), The Effect of Emotion on Cue Utilisation and the Organisation of Behaviour, Psychological Review, Vol 66(3), 183-201 Green, C. D, (n.d.) Classics in the History of Psychology Yerkes and Dodson (1908), Toronto, Ontario, York University, Retrieved from psychclassics.yorka.ca: http://psychclassics.yorku.ca/Yerkes/Law/ Hill, G. (1998), Oxford Revision Guides, AS A Level Psychology, New York, Oxford University Press Loftus, E. F; Loftus, G. R; Messo, J. (1987), Some facts about Weapon Focus, Law and Human Behaviour, Vol 11(1), 55-62 Loftus, E. F. (1975), Leading Questions and the Eyewitness Repost, Cognitive Psychology, Vol 7, 550-572, University of Washington Loftus E. F. (1979), Eyewitness Testimony, Cambridge, Massachusetts, London, England, USA, Harvard University Press Yullie J. C. Cutshall J. L. (1986), A case study of eyewitness memory of a crime, Journal of Applied Psychology, Volume 71(2), May 1986, 291-301 Weiten, W. (2005), Psychology: Themes and Variations, The United States of America, Thomson Learning Inc. Wells, G. L. (1978), Applied Eyewitness-Testimony Research: System Variables and Estimator Variables, Journal of Personality and Social Psychology. Volume 36, No. 12, 1547-1557, University of Alberta, Edmonton, Canada

Crow Lake :: Character Analysis, Kate Morrison

Crow Lake Essay In Crow Lake, Mary Lawson portrays a family who experience a great tragedy when Mr. and Mrs. Morrison are killed in a car accident. This tragedy changes the lifestyles of the seven years old protagonist Kate Morrison and her siblings Matt, Luke and Bo. The settings are very important in this novel. Though there are limited numbers of settings, the settings used are highly effective. Without effective use of themes in this novel, the reader would not have been able to connect with the characters and be sympathetic. Lawson uses an exceptionally high degree of literary devices to develop each character in this novel. The element of setting is used to create a definite atmosphere, and therefore, helping to create a desired mood .In Kate’s childhood, she and Matt visited the ponds regularly. They used to go â€Å"through the woods with their luxuriant growth of poison ivy, along the tracks, past the dusty boxcars lines up receive their loads of sugar beets, down the steep sandy path to the ponds themselves† (Lawson 4). Lawson has used powerful imagery to further describe the ponds. The settings of the ponds are a central part of the story. The ponds are a symbol of the tight relationship between Matt and Kate. They had spent â€Å"hundreds of hours there† (Lawson 15). Ponds were like a home to her. In the prologue, Kate stated that â€Å"there is no image of my childhood that I carry with me more clearly than that† (Lawson 4). The ponds also symbolizes Kate’s childhood. Matt and Kate were able to overcome the tragedy of their parent’s death by visiting t he ponds, but however, they did not survive Matt’s â€Å"disloyalty†. The ponds later developed into the scene of the crime. Kate mentions in the book â€Å"By the following September the ponds themselves would have been desecrated twice over, as far as I was concerned, and for some years after that I did not visit them at all† (Lawson 218). Therefore, the ponds are of great significance in Crow Lake. The setting has developed from a warm, sweet, memorable place to a scene of crime in crow Lake. The theme of isolation is established and developed through the setting of Crow Lake. Located against the deserted territory of Northern Ontario, Crow Lake is a diffident farming settlement that is â€Å"... linked to the outside world by one dusty road and the railroad tracks† (Lawson 9).

The Consumption of Alcohol and its Effects on the Body :: Alcohol Health Drug Abuse Essays

The Consumption of Alcohol and its Effects on the Body Alcohol, probably the oldest drug known, has been used at least since the earliest societies for which records exist. Of the numerous types of alcohol, ethyl alcohol is the type consumed in drinking. In its pure form it is a clear substance with little odor. People drink alcohol in three main kinds of beverages: BEERS, which are made from grain through brewing and fermentation and contain from 3% to 8% alcohol; WINES, which are fermented from fruits such as grapes and contain from 8% to 12% alcohol naturally, and up to 21% when fortified by adding alcohol; and distilled beverages (spirits) such as WHISKEY, GIN, and VODKA, which on the average contain from 40% to 50% alcohol. Drinkers may become addicted to any of these beverages. Physical Effects of Alcohol The effects of alcohol on the human body depend on the amount of alcohol in the blood (blood-alcohol concentration). This varies with the rate of consumption and with the rate at which the drinker's physical system absorbs and metabolizes alcohol. The higher the alcohol content of the beverage consumed, the more alcohol will enter the bloodstream. The amount and type of food in the stomach also affect the absorption rate. Drinking when the stomach is filled is less intoxicating than when it is empty; the foods in the stomach, which contain fat and protein, delay alcohol absorption. Body weight is also a factor; the heavier the person, the slower the absorption of alcohol. After alcohol passes through the stomach, it is rapidly absorbed through the walls of the intestines into the bloodstream and carried to the various organ systems of the body, where it is metabolized. Although small amounts of alcohol are processed by the kidneys and secreted in the urine, and other small amounts are processed through the lungs and exhaled in the breath, most of the alcohol is metabolized by the liver. As the alcohol is metabolized, it gives off heat. The body metabolizes alcohol at about the rate of three-fourths of an ounce to one ounce of whiskey an hour. Technically it is possible to drink at the same rate as the alcohol is being oxidized out of the body. Most people, however, drink faster than this, and so the concentration of alcohol in the bloodstream keeps rising. Alcohol begins to impair the brain's ability to function when the blood-alcohol concentration (BAC) reaches 0.

Love and Loss in Poetry Essay -- First Love Remember Christina Walsh E

Love and Loss in Poetry Q. How do the poets convey their attitudes toward love and loss in the poems ‘ a woman to her lover’ ‘first love’ ‘remember’ and ‘ when we two parted’? The poem ‘ a woman to her lover’ was written by Christina Walsh. The poem starts of with a question, ‘do you come to me to bend me to your will?’ throughout the poem, the basic atmosphere of loss is evident. Within the first stanza itself there is marital imagery relating to the sense of power and dominance. ‘ in drudgery and silence’, she tries to portray how she is helpless to protest, she begins the poem with this relationship, the dominance of man over woman, ‘to make of me a bondslave’ in this stanza she is explaining one of the types of relationships between a man and woman. She also gives out a feeling that if the relationship were as what she described she would be wasting her life, and tries to give out women’s point of view to these types of situations. She seems quite certain of what she wants in life and this does not seem to be it, ‘ if that be what you ask, O Lover I refuse you!’And her point is to prove that if that was the man’s view of the relationship, that it would not be possible to commit to that. In the second stanza she does not keep it as long as the first or any of the others as she does not want to dwell on it. The very idea of the man thinking the woman to be perfect and ‘one from heaven sent’ is what she rejects. When she describes women to be perfect her tone is very mocking. ‘ a wingless angel who can do no wrong’ she tries to convey that that would be someone who would have no freedom. ‘Go’ this implies how she rejects him if he wishes the relationship to be anything like this as well. In th... ...ith silence and tears’ there is a different meaning in this now, they do not understand each other now, but in the beginning they knew each other so well because over the years she has changed so much. The pain and sadness seems to intensify, ‘cold kiss, chill on my brow, knell to my ear’, these are all traditional images of rejected love. The poems octave stanza and regular eight lines, show the continuity of his pain. Throughout all these four poems the poets convey all their attitudes towards love and loss by expressing themselves in situations of love with others, of experiencing it and hence showing reactions and feelings that evolve from certain situations. They show that they feel love is a great thing, and for one to really know the true meaning of love, they need to experience loss and pain the be able to value love to its deserved potential.

Global Warming: Causes, Effects and Possible Measures Essay

Global warming is the term used to describe some of the drastic changes that are taking place in the earth’s climatic conditions. Over the recent years, the term global warming has been the subject of much debate and different people have come up with different views regarding this subject. While many people continue to hold to the view that global warming is a natural phenomenon that cannot be prevented, others are of the opinion that natural as well as man-made factors have accelerated a natural phenomenon to the extent that it has become an international problem, and a threat to human existence. Without global warming, the earth would naturally be a cold uninhabitable place. Through a process that is referred to as the green-house effect, atmospheric gases such as carbon dioxide, nitrous oxide, methane and chlorofluorocarbons have been responsible for trapping the heat radiated from the earth’s surface and subsequently warming the earth. It is through this natural phenomenon that the earth’s average temperatures have been maintained at around 60? Fahrenheit. However, atmospheric temperatures have been rising above the naturally expected rates, and scientists as well as environmentalists have raised concern over these changing climatic conditions, and the effects they will have on human existence. Rising atmospheric temperatures have been attributed to both natural and man-made factors and various suggestions have been raised that hold possible solutions to global warming and its effects on the earth (Peach 2-3). 2. Causes and Effects of Global Warming One of the major causes of global warming is the greenhouse effect. Although the greenhouse effect is a natural phenomenon without which the world would be uninhabitable, there has been a high increase of heat trapping gases in the atmosphere. These gases trap more heat while less of it is radiated back into the outer space, subsequently resulting in global warming. The atmosphere is a combination of many gases which not only enable the sun’s rays to reach the earth’s surface, but also prevent the heat energy that is reradiated by the earth’s surface from escaping back into the atmosphere. Atmospheric gases deflect and scatter about 30% of the sunlight that hits the earth back into space. Through infrared radiation, the rest of the sunlight is reflected back to the atmosphere in the form of slow-moving energy and is absorbed by atmospheric gases which subsequently slow down its escape from the atmosphere. This absorption of energy by atmospheric gases creates a warm-air blanket around the earth; without which this planet would probably be one massive glacier and would not be able to sustain any life (Gonzalez and Sherer 374; Flannery 1-4). Increased human activities such as agriculture, oil production, industry and mining have resulted in an equally increased level of carbon dioxide and other greenhouse gases into the atmosphere. Fossil fuel production and use has especially led to increased carbon dioxide emission and apparently, to 50 % of all human-induced global warming. Since the industrial Revolution, burning of fossil fuels and the use of chlorofluorocarbons and nitrogen fertilizers has led to increased levels of carbon dioxide and other greenhouse gases in the atmosphere. As a result of the Industrial Revolution, agricultural production improved, population grew and urbanization expanded extensively to cater for the urban working masses. All these processes have resulted in massive clearing of forests and other vegetation cover as land is cleared for more food production, for settlement and for mining. Trees naturally help to retain most of the carbon dioxide released into the atmosphere and with the increased loss of trees, the levels of carbon dioxide in the atmosphere have increased and this has led to global warming. Solar activity and volcanic emissions have also contributed to global warming. Scientists argue that the sun has gradually been increasing in strength and since it is the main source of energy, the earth’s atmosphere absorbs approximately 70% of the solar flux. It is the solar flux that has led to increased temperatures not only in the earth’s atmosphere but also in its land and oceans. As climatic and temperature changes occur on the surface of the earth, the sun continues to emit more radiant energy (Peach 3-4, 19-27, 55; Flannery78-79). Global warming adversely affects life on the face of the earth. Various scientists have blamed global warming for rapid changes in weather patterns around the globe and subsequent severe and long draughts in several parts of the world. Spells of dry weather have also been blamed for the catastrophic wild fires that have frequently razed through vast tracts of inhabited land in California, U. S. A as well as for the heat waves that swept through Europe during the summer of 2003 and caused the death of about 35,000 people. Scientists have also suggested that rising atmospheric temperatures could be the cause of severe storms, tornadoes and hurricanes such as those experienced in southeastern U. S. A and other parts of the world (Flannery 132-141). Excessive heat transferred back to the atmosphere causes strong winds and also fuels the storms. Rising atmospheric temperatures have also been blamed for the massive melting of glaciers in Greenland and Antarctica as well as most mountain tops of the world. As these glaciers retreat, the melted ice in turn flows down into the seas and has attributed for rising ocean levels. According to experts, the sea level is expected to rise by about 30 cm by the year 2100 and may cause flooding or even disappearance of coastal towns. About two thirds of the world’s major cities have been built along coastlines and their existence as well as that of their future developments will continue to rest upon the effects of global warming (Valsson 17-25; Peach 38-39). While it is common to conceptualize the impacts of such scenarios and effects upon humans, there is definitely truth in claiming that the detrimental effects of global warming affect all life on the planet. To further explain, a vast number of creatures or organisms throughout the world. In general, encompassing changes to the temperature of the Earth would mean that creatures would have another concern to tackle in order to maintain survival. Specifically, both flora and fauna which currently reside in a given location, live optimally at the particular climate present at the aforesaid region; changes in temperature may result in the proliferation of illnesses and even extinction (Craighead 123). In contrast, some creatures might further proliferate in the presence of global warming. The growth of squids for example have been known to be enhanced by the increasingly warmer oceans which resulting in a considerable increase in its number throughout the seas (AtKisson 44). While this may seem beneficial, it is important to emphasize that ecological balance would potentially be compromised by such effects of global warming. Furthermore, while migration to other areas would have been the expected course of action for animals and even plants to survive the region altering effects of global warming it is now virtually impossible to accomplish as human activities and settlements have considerably spread (Schneider and Root 3). Before dismissing the abovementioned effects of global warming as secondary to its implications upon humans, it is essential to point out that human survival heavily relies on the riches of nature. 3. Possible Solutions to Global Warming Processes such as increased agricultural production, industrialization and urbanization have contributed to massive loss of the world’s vegetation cover and subsequent global warming; but are quite difficult to control or reverse. But global warming can be controlled through responsible environmental management procedures. Re-forestation probably remains the most practical and perhaps most effective measure of reducing the effects of a warmer earth. Through reforestation, the atmospheric cycle will be maintained at close to normal levels and in such way, atmospheric temperatures will be reduced; in relation to this, the rate at which forested land is being converted to other land use activities should also be continuously checked. Public transport should be encouraged especially when traveling for short distances because this helps to put a check on the burning of so much fossil fuel. Complete rehabilitation of destroyed environment takes hundreds of years; and preserving the existing forest cover through sustainable development becomes very crucial towards preserving the temperate and tropical forests that face destruction every year. It is also advisable to educate the masses on the advantages of using electric appliances that use less heat as well as the use of energy-saving bulbs (Peach 45-55). Aside from creating positive changes in the manner of energy production, resource management, and daily living, means to limit and eventually eliminate the release of greenhouse gases into the atmosphere should also be highlighted. Considering the state of technology and manufacturing today, it would be appropriate to assume that immediately eliminating all the industrial processes which create greenhouse gases is an impossible feat. However, there are ways to gradually make corporations and firms worldwide to reconsider more environmental methods of production and energy usage. One of the most promising of which is the implementation of a strict, and possibly internationally applied, carbon tax. To explain, as carbon is considered to be one of the most common greenhouse gases derived from industrial endeavors due to the use of fossil fuels, a taxation system which results in greater expenses for heavy users of fossil fuel would supposedly result in transitions to the use of clean energy (McKinney and Schoch 434). Subsequently similar policies, either worldwide or specific to a country, should be drawn that advocate more dependence on renewable energy such as solar, wind and geo-thermal and less dependence on fossil fuel. While global warming may be partly addressed through lifestyle changes which are depended upon personal choice as discussed beforehand, it is undeniably that the actions of governments or world leaders are essential if the world would indeed survive and resolve the issues brought forth by global warming; such leaders and politicians hold the key to actualizing the needed transitions in society. 4. Conclusion Global warming and the potential effect it has on the environment and global human societies are still difficult to put on scale because of the uncertainties that accompany the scope of the problem; despite such, it is irrefutable that the detrimental effects of global warming upon human lives, as well as both flora and fauna, have become an evident proof of the presence of the concern. As industrialization advanced greenhouse gases were released into the atmosphere on a very large scale and global temperatures have been on the increase. But there is increased international attention directed towards reduction of these gases from man-made sources; as well as drawing of policies towards the best methods of adapting to the possible impacts that global climatic change will bring along. A long-term solution will however require the global cooperation since global warming has been the result of greenhouse emissions from all countries of the world. Since emitted gases continue to have their effect, more emission should be controlled. Both short-term and long-term policies should be put into consideration (Peach 44-45, 57). Therefore, in order for humanity to resolve the issue of global warming and ensure that life on Earth would ensue in its rightful manner, continuous vigilance of the changes in the environment as well as superb planning and problem solving skills are all of great importance, but not as essential as establishing global awareness and unity. Works Cited AtKisson, Alan. The ISIS Agreement: How Sustainability Can Improve Organizational Performance and Transform the World. Sterling, VA: Earthscan Publishing, 2008. Craighead, Lance. Bears of the World. St. Paul, MN: Voyageur Press – MBI Publishing Company, 2000. Flannery, Tim F. The Weather Makers: How Man is Changing the Climate and What it Means for Life on Earth. New York, NY: Atlantic Monthly Press, 2006. Gonzalez, Joseph and Thomas E Sherer. The Complete Idiot’s Guide to Geography. Phoenix, AZ: Alpha Books, 2004. McKinney, Michael L. and Robert M. Schoch. Environmental Science: Systems and Solutions. 3rd Edition. Sudbury, MA: Jones and Bartlett Publishers, 2003. Peach, Dexter J. Global warming: Emission Reductions Possible As Scientific Uncertainties Are Resolved. Darby. PA: DIANE Publishing, 2005. Schneider, Stephen H. and Terry L. Root. Wildlife Responses to Climate Change: North American Case Studies. Washington, DC: Island Press, 2002. Valsson, Trausti. How the World will Change with Global Warming. Reykjavik, Iceland: University of Iceland Press, 2006.

Sunni Islam

Sunnis Several years after Muhammad's death, the various factions of the Islamic faith were formed. Many of Muhammad's relatives and companions were involved in the power struggle, and the war finally stabilized when Mu'awiyya, the governor of  Syria, took control of the Caliphate. This marked the rise of the  Umayyad dynasty  which ruled Islam for quite some time. Although the Qur’an ordains that the division of Muslims into different sections is forbidden, three sects of Islam developed and emerged at the conclusion of the  Islamic Civil War.These include the Sunni, Shiite, Ahmadiyya and Karijite. Of these four, the Sunni denomination is by far the largest, comprising of 90% of the world Muslim population, with Shi’a comprising of the second largest percentage. The literal translation of the word Sunni is â€Å"habit† or usual practice. My assumption is that the habit or practice refers to the actions of Muhammad. So anyone claiming to follow the Sunnah , which are the actions of Muhammad and can show that they believe the Hadith, which are narrations of the actions of Muhammad, can consider him or herself to be a  Sunni  Muslim.People of Sunni orientation believe that Muhammad had never chosen a successor before his death and therefore nobody can really properly succeed him or become the succeeding leader of the Caliphate other than his closest companions, or Shahaba. Sunnis belive that only the the first four caliphs should be regarded as the properly led caliphs. They include Abu Bakr, Umar al-Khattab, Uthman Affan, and Ali Talib. Actually why there has not been one widely known caliph since 1923 for the entire Islamic religion is due to the fact that Islam is divided into these three sections metioned earlier.Although Sunnis accept hadith narrated by the first four caliphs, they regard one collection of hadith to be the most authentic. This is called the Sahih al Bukhari. The literal translation of sahih is â€Å"authentic †. The Sunni branch of Islam has four legal schools of thought or  madh'hab, through which Sunnis practice religious jurisprudence, or religious philosophy. There was only one madh-hab during the time of the â€Å"rightly-guided† Caliphs but after the beginning of the Umayyad dynasty, things changed. The Umayyad caliphs did not have the same religious authority as the previous ones.After the Umayyad Dynasty, there was the Abbasid Dynasty. In comparison to the Umayyads, they were more supportive of Islamic law. The crystallization of four major Sunni madh’hab of Islamic fiqh came about by the third century of Hijra. These four include the Hanafi, which was founded by Abu Hanifah and is the dominant school of Muslims in the United Kingdom and Germany, and also followed by Muslims in Bangladesh, Pakistan, India, and Afghanistan. The Maliki school, founded by a Hanifa’s eldest student named Malik ibn Anas and is the dominant school of Muslims in Morocco, Alg eria, Libiya, Nigeria, Sudan Bahrain, UAE and Kuwait.The Shafi’i school founded by a student of Malik named Muhammad ibn Idris ash-Shafi’i and is the dominant school of Muslims in Indonesia, Egypt, Malaysia, Brunei, Singapore, Kenya, Somalia, Kenya Tanzania, Jordan, India, Syria and Lebanon. The Hanbali school founded by a student of al-Shafi’i named Ahmad bin Hanbal, and is the dominant school of Muslims in the Arabian Peninsula, to name the most predominant ones. The followers of these four schools follow the same basic beliefs but differ from one another in terms of practice and execution of rituals, and in interpretation of Shari’a.So rather than again dividing themselves up into different schools of law, Sunnis rather prefer to just combine and call themselves all Sunnis. The  religious text of Islam, the Qur'an  was compiled by Muhammad’s closest companions and regarded as authentic my all Muslims. There are many aspects of daily life, ho wever that are not mentioned in the Qur’an but they were observed and passed down through generations. These oral account are called hadith. Sunnis regard only certain collections of hadith to be authentic and those are compiled by six specific recorders named Bukhari, Muslim, Nasa’ii, Dawud, Tirmidhi, and Majah.The history of the Sunni–Shia conflict originates in the  split  that occurred when  Muhammad  died in the 632 which led to a dispute over  who should succeed him as  caliph  of the Islamic community. This led to the battle of Siffin. For a long time, Sunni Islam was differentiated from Shi'i Islam by its adherence to the  Caliph  as the leader of the Muslims. However, Sunni and Shi'i Islam are the same in that they share important taught principles: the wholeness of  God, the belief in the revelations of Muhammad, and the belief in resurrection on the Day of Judgment.Even though the main split in Islamic practice is between Sunni and Shi'a Muslims, there are several disagreements within the Sunni community. Almost like how Americans have different views, there are some liberal and more secular movements in Sunni Islam that say that Shari'a is interpreted on an individual basis, and that reject any  fatwa  or religious edict by religious Muslim authority figures. There are also several movements in Sunni Islam, which reject and sometimes persecute liberal Muslims for attempting to compromise certain Muslim traditions.