Technical Analysis of elite male soccer players by position and success Essay Example

Technical Analysis of elite male soccer players by position and success Paper Since the early work of Reep and Benjamin (1968), many aspects of association football have been utilised by researchers within notational analysis. Several researchers (Reilly and Holmes, 1983; Luhtanen, 1988; Dufour, 1993) have however identified the lack of literature existing detailing the exact technical demands with regard to their relative successful performance between specific positions of play. The purpose of the investigation was to deliver such a technical analysis of playing positions within elite level International football at the European Championships 2004. The data were gathered by a specifically designed notation system which collected qualitative data based on the relative successful execution of techniques performed, post event. Players were grouped into positional classes as goalkeepers, defenders, midfielders or strikers. A comparison was also made between the technical distributions of both a successful and unsuccessful team. The Chi Squared statistical test was used to compare differences between the frequency distributions and the differences in technical ratings between positions and the successful and unsuccessful teams. Significance was accepted at the (p0.05) level (Vincent, 1999). Significant differences (p0.05) were found between the frequency distributions of all 3 outfield positions, but no significant differences (p0.05) were found between the accumulated means of technique ratings across all of the performance indicators. Individual variable analysis however showed significant differences (p0.05) occurred between specific performance indicators across positions. We will write a custom essay sample on Technical Analysis of elite male soccer players by position and success specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Technical Analysis of elite male soccer players by position and success specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Technical Analysis of elite male soccer players by position and success specifically for you FOR ONLY $16.38 $13.9/page Hire Writer No significant differences (p0.05) were discovered between either the frequency distribution or the technical rating of outfield players between successful and unsuccessful teams. A significant difference (p0.05) was however apparent between the frequency distribution of goalkeepers actions between successful and unsuccessful teams. The study implicates that coaches must be selective of which players play within certain positions and that training sessions must be accurate to the specific needs of individuals and their position within a team. 1.0 Introduction The process of hand notation is an important tool, which can be used to inform the coaching process. Hand notation is a cheap, simple, accurate but time consuming method of notation (Hughes and Franks, 2004). It provides a coach with an objective view of the key elements of a performance. Notational analysis can provide many aspects of information to a coach. Hughes (1998) defined the 5 purposes of notational analysis: 1. Analysis of Movement; 2. Educational use for both coaches and players; 3. Tactical Evaluation; 4. Development of a data base/modelling; 5. Technical Evaluation. Due to its structure of incorporating individual techniques within a team framework, association football provides a notational analyst with an ideal field for analysis. Within association football, the use of notational analysis enables coaches to improve aspects of their own teams play, at both an individual or collective level and also to interpret the actions of any future opposition. Reilly and Thomas (1976) adapted a methodology in order to analyse players movement, or more specifically work rate within different positional roles in a first division football team. Observations were made over the course of a season, incorporating a total of 51 competitive games, both home and away. Players movements throughout a game were subdivided into several distinct movement classifications. This allowed the individual movement characteristics of different positional roles to be established and therefore for accurate training strategies to be incorporated. The use of feedback was identified by Franks (1997). Feedback can have an educational use for both players and coaches, as it is an important component of the coaching process. Franks stated that any improvement in performance is a consequence of task related feedback. Feedback can be provided before, during and after a skilled performance to both specific individuals and to whole teams alike. A tactical evaluation of association football was achieved by Yamanaka et al., (1997) who performed a computerised notational analysis of 8 games in the 1994 World Cup Asian Qualifying matches. The respective playing patterns of the teams were analysed, with a particular emphasis upon the Japanese national team. This was achieved by entering 32 actions of players in relation to an 18 cell division of the pitch. From the data it was found statistically significant that Japan used dribbling more as a tactic (p0.05), used more passes (p0.01) and more frequently used a clearing kick (p0.05). Garganta (1998) suggested how the development of a soccer data base/model can be considered as a mediator between a theoretical and an empirical field. He states that it is important to understand a soccer teams organisation and to observe a whole teams actions. Garganta explained how game modelling is acquiring greater importance in order to analyse performance trends and to prioritise any such problems of the training process. A technical evaluation was achieved by Partridge et al., (1993). A specialised computer analysis system was developed, using 38 key events entered in real time by a trained analyst. The system was used to provide a comprehensive technical evaluation of performance by comparing the results of 2 distinct levels of performance, the 1990 FIFA World Cup and the 1990 World Collegiate Soccer Championships. From the results it can be inferred that collegiate coaches must be selective when presenting World Cup teams as an appropriate model of performance as many differences do occur, which makes any comparison invalid. At International football level, where games are decided by small margins, the team that is superior in physiological and motor abilities will have the advantage (Reilly and Holmes, 1983). This places a high emphasis on a team at the elite level possessing high levels of technical ability. Within the literature, there are very few examples of technical analysis, in particular skill analysis involving association football. In this respect, the following study is innovative in two ways: i) By analysing at the exact technical requirements of each position ii) By using qualitative data within a quantitative system. 1.1 Aim of Study The aim of this study is to analyse every individuals technical ability that competes in the European Football Championships of 2004. This measure will be based on a subjectively drawn continuum that analyses a players technical movement throughout the game. It will be investigated if technical differences occur between player positions and between successful and unsuccessful teams. Data will be gathered from matches within the European Championships of 2004, which were held in Portugal. This tournament has been chosen as it provides an ideal environment for a comparison to be made between elite level players competing in an elite sporting environment. Data will be collected using a hand notation system, in the form of a table. The table will consist of six columns: player number; technique performed; technique rating, pitch position, time of action and any outcome (if applicable). 1.2 Hypothesis The hypothesis states that there is a significant difference in the distribution of technique between the different playing positions and between successful and unsuccessful teams at the European Championships 2004. 1.3 Assumptions Certain assumptions are considered during this study. It is assumed that all players selected are of international standard and that all players are competing in the tournament to win. 1.4 Limitations Limitations of the study that depict the nature and length of the investigation include the word limit imposed and the submission date. Variations from the tournament itself may also not give the data a true reflection of reality. Incidents such as injury to key players, conditions and the environment may impact on the manner in which a team or certain individuals perform. As the matches were all recorded from terrestrial television, some data cannot be collected due to its absence from the showing of action replays and other inappropriate footage (Winkler, 1996). The choice of some camera positions and angles also makes some forms of player identification difficult. 1.5 De-Limitations A de-limitation from our research design is that it is impossible to make broad generalisations from our data. The obtained data is so specific to the tournament and elite level players that any such generalisation would be inaccurate and invalid. The analysis is also produced in a very subjective manner using operational definitions and a likert scale, which may also not be universally agreed by people other than the researchers. 1.6 Definition of Terms Technique: The method of performance of an individual against a normative scale. Player Position: An individuals role and function within a teams structure. 2.0 Literature Review 2.1 Notational Analysis in Football Some of the earliest analysis of association football was carried out by Reep and Benjamin (1968). They analysed over 3000 competitive games from 1953 to 1967 within top division English football and World Cup matches using a simple hand notation system. The position of players actions, the amount of passes before goals and the way in which possession was gained were all notated. From this extensive analysis it was reported that: i. 80% of goals resulted from 3 passes or less ii. 50% of goals result from regaining possession in the final attacking 1/4 iii. It takes 10 shots to score 1 goal Many coaches and managers throughout the English game saw these results as an immediate formula for success. The transfer of these findings into a game situation saw the arrival and development of the traditional long ball game within British soccer. The work of Reep and Benjamin was later taken on further by Bate (1988) in an attempt to disprove a modern day notion that maintaining possession of the ball was the key to accomplishment. From analysing games in the English 3rd division, right up to World Cup level competition, Bate concluded that in order to be a success, teams must portray the following characteristics in their play: i. Play the ball forward as often as possible ii. Reduce the number of square and backwards passes iii. Increase the number of forward passes and forward runs iv. Play the ball into the space behind the defenders as early as possible From Bates (1988) analysis, it can be seen that the determinants of success across a wide range of football were relatively unchanged for a long period of time and that the notion of possession football was not the key to success. Further characteristics of successful play were noted by Winkler (1996). He stated that good teams are capable of defending their own goal well as well as creating more goal scoring opportunities than the opposition. His findings were however contradictory to the research of both Reep and Benjamin (1968) and Bate (1988) by suggesting that successful teams should keep possession of the ball for longer, as opposed to getting the ball as forward as quickly as possible. More recently Luhtanen et al., (2001) adapted a methodology from Luhtanen (1993) to study selected offensive and defensive variables of individuals within the European Championships of 1996 and 2000. The study aimed to examine if any correlation occurred between performance and final position reached in the tournaments. A computerised notation system was used to notate over 2000 actions per game. The actions of the individuals could then be calculated to give means for each of the teams per selected variable. France, who were the winners of Euro 2000 were found to be the highest ranked nation in passing, receiving the ball, running with the ball and tackling. Luhtanen et al. (2001) concluded that this consistent high ranking suggested that France were worthy winners of the tournament. The winners of Euro 1996 however, Germany, were not found to be the highest ranked in any selected variable. Luhtanen et al. (2001) explained this concept by stating that the Germans performed very ordi narily throughout the tournament, and a great deal of luck brought them success. The selection of performance indicators for use in the study may however have only been conducive to certain patterns and styles of play. Although these may have highlighted the attacking nature of Frances performance, they do not take into account factors such as levels of team cohesion and team organisational structure. It may have been high levels of factors such as these which brought the Germans success, not merely luck, as was stated in the review. Luhtanen et al., (2001) summarised that comparisons between team performances across tournaments or time spans couldnt be made absolute due to the numerous changes in team selections, opposition, tactics used and managerial changes. 2.2 Factors determining success within association football Vast amounts of literature are apparent concerning the various aspects of a teams performance, especially those, which bring success. Hughes et al., (1988) developed a methodology to differentiate between successful and unsuccessful teams from the 1986 World Cup by examining the main characteristics of play when in possession of the ball. Successful teams were defined as those teams who progressed to the semi final stages, whereas unsuccessful teams were those who were eliminated after the 1st group stage. Analysis was conducted using 24 performance variables. It was found that successful teams have more touches in possession, had more shots at goal from within the penalty area and approached the final sixth of the pitch by playing predominantly in the central areas. Unsuccessful teams dribbled more and played the ball to the wide areas in their own defensive zones more frequently. The findings of Hughes et al., (1988) study were contradicted by Ali (1988) who conducted a statistical analysis of patterns of play in 18 Scottish Premier Division matches. It was concluded that attacks which proceeded along either wing were more successful, rather than those which were played more centrally. Teams using low pass combination moves combined with centrally based attacks were the factors deciding success in Bishovets et al., (1993) study of 52 World Cup matches. This manner of performance was related to winning teams have a more consistent and reliable understanding between players. Pearce and Hughes (2001) conducted analysis of the perceived successful impact of substitutions in the 2000 European Championships. Data was gathered in the 15 minutes preceding a substitution and in the 15 minutes afterwards. Each performance variable was evaluated and ranked depending on its value of influence. This allowed a show of ratings along a continuum to be created, both of the individual substitute and of the teams performance following the substitutes introduction. Although it was found that 15 minutes of analysis did not produce enough data, midfield was seen to be the most hazardous player position in which to introduce a substitute, due to the high work intensities required immediately by the incoming player. The idea of coding actions according to their difficulty and their success can also been seen in Rico and Bangsbo (1997) study of Denmarks performance in the 1992 European Championships. Actions were noted according to the amount of pressure applied on the performer and conclusions were drawn from the results. The decline of Denmarks passing in their final 3 games was put down to the increased pressure and closeness of the score line related to the latter stages of the tournament. Dooan et al., (1996) conducted a further study to determine the factors, which promote success within soccer. The importance of playing at a high tempo was recognised, due to the constant opponent and time pressures that are placed upon performers. He aimed to compare the efficiency of pass in elite versus non-elite Turkish performers. All passes were recorded as either positive or negative, according to their perceived degree of difficulty and success. It was concluded, as expected that speed, fluency and intensity of pass are all more apparent for elite performers. A further technical study on elite Turkish footballers was reported by Eniseler et al., (1996). The researchers found that Galatasarys failure in European football competition was due to technical and tactical inadequacies as well as a lack of physical conditioning. This method of performance profiling also included recording variables as either positive or negative, according to their execution. A tactical and technical inadequacy leading to failure was also reported by Acar (1996) who analysed the performance of teams playing in derby matches, using both computer and hand notation. The stated research has all described the relative success of play in relation to entire team performances. A team is defined as a system in that a group of players interact in a dynamic fashion concerning a single purpose (Pinto, 1998). Despite a team participating as a homogenous unit, it is also vital to remember that the different individuals comprising a single team make it heterogeneous at the same time (Pinto, 1998). 2.3 Evaluation of Individuals Performance Success in football is very much judged on a teams ability to win matches (Luhtanen et al., 2001). The study of individuals performance can be regarded as invaluable as it is in essence these individuals which comprise any team. Success at any level collectively cannot be achieved without the performance of individuals within this team unit. A great deal of individual analysis has been conducted on the physical demands of football competition and the necessary physiological state for optimum performance (Reilly and Thomas, 1976; Bangsbo, 1997; ODonoghue et al., 2001). Wells and Reilly (2002) attempted to research into the demands of playing position within womens soccer also taking into account performance variables. However the only performance variable measured was kicking distance. This variable seems very irrelevant to determining successful performance within a game situation, particularly within elite level International football. The lack of literature relating to the importance of individuals levels of skill was identified by Reilly and Holmes (1983). Reilly applied 2 methods in order to investigate the notion of skill distribution within soccer. Match analysis of 6 non professional games was carried out looking at skill performances as either successful or unsuccessful. In addition to this analysis, a group of 40 adolescent males, from a variety of outfield positions performed a cross section of skills tests. From the 2 tests, Reilly concluded that significantly: i. Success rate of each skill depends upon pitch location ii. Defensive area provides highest skill success rate iii. Midfield players show more superior test scores to defenders Reilly explained that as the space available from the opponents goal increases, the time available on the ball also increases. This explains why the most successful skills are performed in the defensive area, where less pressure is applied. It was also suggested that a common trend is to place the most poorly equipped players in defensive roles, hence the defenders performing worst on the skills test. James at al., (2002) recognised the importance of studying individuals within a team. He stated that this level of deeper analysis allows a much finer grained overall team examination. In a study of the same team over 21 matches, across various competition types, the analysis aimed to identify the different roles individuals may take across differing circumstances. It was noted that in European competition players played more defensively and played passes involving much less risk. Dufour (1993) completed a technical analysis of outfield players, summarising the percentage of time spent in each action category. For an outfield player it was reported that on the ball playing time was divided into: 50.6% Intercepting, 22.4% Passing, 18.7% Controlling ball, 4.5% Tackling, 2.4% Shooting and 1.4% other activities. Although this analysis enabled a template of the aspects contributing to an outfield players role, no specification was made relating to playing position, taking into account the obvious differences which occur between the outfield positions. The lack of individual analysis relating to the highly specialised position of a goalkeeper was identified by Wooster and Hughes (2001). Goalkeepers were seen as vitally important, as they provide the last line of defence and the first line of attack for any team. From studying 1126 goalkeeper distributions at Euro 2000 with a hand notation system, it was concluded that successful goalkeepers used an equal distribution of kicks and throws, with variety which enabled possession to be maintained in the attacking third of the field. 24% of the 67 goals scored within the tournament all originated from successful goalkeeper distribution. Researchers have also used other methods, other than standardised hand and computer notation systems in order to investigate the performance of individuals. A qualitative analysis of individual movement patterns was performed by Grehaigne et al., (2001). A players effective play space was considered by drawing polygonal lines to create an individuals players action zone. This action zone represented the areas in which 80% of the players activities were performed. Graphic modelling and statistical calculations were used by Chernenjakov and Dimitrov (1988) to help detail individual players performances. By entering specific data into a computer, it allowed players to be arranged in order of their playing effectiveness. Erdmann (1993) described how due to the imprecise, subjective and ambiguous nature of qualitative observations, all quantitative analysis should be performed based upon mechanical properties. Erdmann introduced how by looking at the Kinematics of movement, such as the displacement, velocity and acceleration of movements, individual performance profiles could be built. 2.4 Use of Match Analysis by Coaches As stated by Coghlan (1990) there is enormous pressure on football mangers throughout the world to succeed. In an attempt to bring about such success, notational analysis is being increasingly used within the modern game (Partridge and Franks, 1997). It can help to provide coaches with detailed analysis of observations that would otherwise be missed (Coghlan, 1990). Many coaches now consider information derived from such technological advances to be invaluable (Liebermann et al., 2002). With the pace of the modern day game, team strategies and tactics should be based on something more substantial than opinion (Bate, 1988). Match analysis enables accurate, objective and relevant feedback to be applied to a coach or a performer about past performances (Franks and McGarry, 1996). Due to coaches being active, biased observers of their teams performances, their observations are often not accurate. In a study by Franks and Miller (1986), International level coaches were only able to recollect 30% of the key elements which determined performance with the use of their memory alone (cited in Franks and McGarry, 1996). The presentation of accurate results takes away any subjective views and opinions and allows a coach to build up a portfolio of all future opponents in order to prepare to play against them (Pollard et al., 1988). Olsen and Larsen (1997) showed how the outcome of analysis can be a tool for evaluation and for the development of team tactics. The system responsible for such analysis must however be valid, accurate and easy to use, without large tables of complicated figures and graphs (Gerisch and Reichelt, 1993). Such simple but detailed analysis systems have enabled Norway to maximise its limited resources and to compete on the International football arena (p.220). Franks and Goodman (1986) stated that an objective quantification of critical events during a game is critical for a complete post match analysis. The generated analysis must be used by coaches to instigate an observable change in behaviour, and so an improvement in performance. Liebermann et al., (2002) and Franks and McGarry (1996) reinforced this notion by stating that appropriately timed feedback can significantly improve motor skill acquisition and performance. Reporting to the results of both qualitative and quantitative feedback to a performer can increase performance (Partridge and Franks, 1997). Following matches, a subject was shown analysis results, and video clips from relevant expert performances which related to his previous performance. Over the course of 6 games, the subjects performance across 15 measured variables did improve. This performance increase was directly related to the analysis procedures the player was subjected to between performances. 2.5 Individual Roles Within a Team Framework Although a team unit is comprised of 11 individuals, all 11 players must assume certain roles and functions in order to make such a team unit a success. Subconsciously, players and coaches alike have a universal knowledge of which technical components are required in order to play in each position within association football. There is however very little research to either reinforce or question these concepts. Having an exact technical analysis of the precise playing requirements of each position would allow accurate training schedules and more accurate player profiles to be established. Many coaching publications state the necessary credentials to play in certain positions within soccer (Smith, 1973; Cook, 1982). These publications are however based upon opinion, as opposed to exact epidemiological research. Much ambiguity does exist between these opinions and the reported differences. Wiemeyer (2003) in interviewing 14 coaches, across varying participation levels in order to establish positional technical demands emphases this. In only one case did all coaches agree of the exact functions of a position.

Writing a Sample Five Paragraph Essay For Middle School

Writing a Sample Five Paragraph Essay For Middle SchoolIf you have never written a sample five paragraph essay for middle school, you are missing out on one of the greatest opportunities to discover your writing style guide. Though this is not a difficult course for a first time writer, it is a difficult one for a person who has never written anything this size. This article will discuss five paragraphs that you should be familiar with before starting the essay.The first paragraph should begin with a prompt. This can be a specific date such as April 1st or it can be something that has already happened, such as 'The paper was written the day before the patient passed away.' Whatever prompts your, use them to start the essay. It is usually the first paragraph that gives the most importance because it establishes the format of the rest of the essay.The second paragraph must give a rationale for the change in form. Since this will be in the form of an essay, it must establish the reason for the change. Try to incorporate new ideas into the current format to keep the reader interested. You can either include a specific example or you can give the reader some examples.The third paragraph should include the problem and the solution. Explain the problem clearly and support it with the solution. As long as the solution does not contradict the problem, the reader will be able to understand it easily. However, it is possible that the problem could be addressed more clearly by giving a concrete example of the problem.The fourth paragraph should end with the conclusion. Give a specific end date and explain the details of how the essay can be submitted. Once again, it is possible that the problem may be addressed more clearly if you provide a concrete example to explain what happened.The fifth paragraph should be about the teacher's influence on the student. Use the example of a doctor whose patient died due to the doctor's negligence. In this case, it is important to cite t he doctor's error rather than a specific date, but since the student used the doctor's mistake to complete his masterpiece, the writing skill should be focused on how he overcame the obstacle instead of simply quoting the date.There are many more examples, but you get the idea. The key to writing this kind of essay is to follow the format you have learned in the first four paragraphs, and it is just a matter of applying that knowledge to the writing process.

Colored Smoke Recipes - Easy Formulations

Colored Smoke Recipes - Easy Formulations One way to make smoke is to craft a smoke bomb, but you can make a smoke powder, too. Here are some formulations for colored smokes. The parts or percents are by weight. Basically what you do is measure the ingredients, sift them together to mix them, and ignite the powder to produce smoke. Up to 2% sodium bicarbonate (baking soda) may be added to slow the combustion/cool the reaction, if necessary. White Smoke Recipe Potassium nitrate - 4 partsCharcoal - 5 partsSulfur - 10 partsWood dust - 3 parts Red Smoke Recipe Potassium chlorate - 15%para-nitroaniline red - 65%Lactose - 20% Green Smoke Recipe Synthetic indigo - 26%Auramine (yellow) - 15%Potassium chlorate - 35%Lactose - 26% Reference: The formulations for colored smoke bombs came from Wouters Practical Pyrotechnics, who cited the recipes as originating from L.P. Edel, Mengen en Roeren, 2nd edition (1936). Wouters website is very helpful. Though I didnt see recipes for other colors of smoke, he has an extensive list of formulas for colored fireworks, which you may be able to adapt to make colored smoke. More Dyes and Colors If you can order chemicals, here are some of the dyes used to produce more colors: Red: Disperse Red 9 (older formulation)Solvent Red 1 with Disperse Red 11Solvent Red 27 (C.I. 26125)Solvent Red 24 Orange: Solvent Yellow 14 (C.I. 12055) Yellow: Vat Yellow 4 with benzanthrone (older formulation)Solvent Yellow 33Solvent Yellow 16 (C.I. 12700)Solvent Yellow 56Oil Yellow R Green: Vat Yellow 4 with benzanthrone and Solvent Green 3 (older formulation)Solvent Yellow 33 and Solvent Green 3Solvent Green 3Oil Green BG Blue: Solvent Blue 35 (C.I. 26125)Solvent Blue 36Solvent Blue 5 Violet: Disperse Red 9 with 1,4-diamino-2,3-dihydroanthraquinoneSolvent Violet 13 Use care if you try these additional dyes. If you know of a reliable reference for additional colored smoke formulations, please feel free to contact me. Colored Smoke Safety Information Read and follow the safety information for all the chemicals that you use. Use colored smoke outdoors only, in a well-ventilated area. Disclaimer: Please be advised that the content provided by our website is for EDUCATIONAL PURPOSES ONLY. Fireworks and the chemicals contained within them are dangerous and should always be handled with care and used with common sense. By using this website you acknowledge that ThoughtCo., its parent About, Inc. (a/k/a Dotdash), and IAC/InterActive Corp. shall have no liability for any damages, injuries, or other legal matters caused by your use of fireworks or the knowledge or application of the information on this website. The providers of this content specifically do not condone using fireworks for disruptive, unsafe, illegal, or destructive purposes. You are responsible for following all applicable laws before using or applying the information provided on this website.

Battle of Five Forks - Civil War

Battle of Five Forks - Civil War Battle of Five Forks - Conflict: The Battle of Five Forks occurred during the American Civil War  (1861-1865). Battle of Five Forks - Dates: Sheridan routed Picketts men on April 1, 1865. Armies Commanders: Union Major General Philip H. SheridanMajor General Gouverneur K. Warren17,000 men Confederates Major General George E. Pickett9,200 men Battle of Five Forks - Background: In late March 1865, Lieutenant General Ulysses S. Grant ordered Major General Philip H. Sheridan to push south and west of Petersburg with the goal of turning Confederate General Robert E. Lees right flank and forcing him from the city. Advancing with the Army of the Potomacs Cavalry Corps and Major General Gouverneur K. Warrens V Corps, Sheridan sought to capture the vital crossroads of Five Forks which would allow him to threaten the Southside Railroad. A key supply line into Petersburg, Lee moved swiftly to defend the railroad. Dispatching Major General George E. Pickett to the area with a division of infantry and Major Gen. W.H.F. Rooney Lees cavalry, he issued orders for them to block the Union advance. On March 31, Pickett succeeded in stalling Sheridans cavalry at the Battle of Dinwiddie Court House. With Union reinforcements en route, Pickett was forced to fall back to Five Forks before dawn on April 1. Arriving, he received a note from Lee stating Hold Five Forks at all hazards. Protect road to Fords Depot and prevent Union forces from striking the Southside Railroad. Battle of Five Forks - Sheridan Advances: Entrenching, Picketts forces awaited the anticipated Union assault. Eager to move quickly with the goal of cutting off and destroying Picketts force, Sheridan advanced intending to hold Pickett in place with his cavalry while V Corps struck the Confederate left. Moving slowly due to muddy roads and faulty maps, Warrens men were not in position to attack until 4:00 PM. Though the delay angered Sheridan, it benefited the Union in that the lull led to Pickett and Rooney Lee leaving the field to attend a shad bake near Hatchers Run. Neither informed their subordinates that they were leaving the area. As the Union attack moved forward, it quickly became clear that V Corps had deployed too far to the east. Advancing through the underbrush on a two division front, the left division, under Major General Romeyn Ayres, came under enfilading fire from the Confederates while the Major General Samuel Crawfords division on the right missed the enemy entirely. Halting the attack, Warren desperately worked to realign his men to attack west. As he did so, an irate Sheridan arrived and joined with Ayres men. Charging forward, they smashed into the Confederate left, breaking the line. Battle of Five Forks - Confederates Enveloped: As the Confederates fell back in an attempt to form a new defensive line, Warrens reserve division, led by Major General Charles Griffin, came into line next to Ayres men. To the north, Crawford, at Warrens direction, wheeled his division into line, enveloping the Confederate position. As V Corps drove the leaderless Confederates before them, Sheridans cavalry swept around Picketts right flank. With Union troops pinching in from both sides, the Confederate resistance broke and those able to escape fled north. Due to atmospheric conditions, Pickett was unaware of the battle until it was too late. Battle of Five Forks - Aftermath: The victory at Five Forks cost Sheridan 803 killed and wounded, while Picketts command incurred 604 killed and wounded, as well as 2,400 captured. Immediately following the battle, Sheridan relieved Warren of command and placed Griffin in charge of V Corps. Angered by Warrens slow movements, Sheridan ordered him to report to Grant. Sheridans actions effectively wrecked Warrens career, though he was exonerated by a board of inquiry in 1879. The Union victory at Five Forks and their presence near the Southside Railroad forced Lee to consider abandoning Petersburg and Richmond. Seeking to take advantage of Sheridans triumph, Grant ordered a massive assault against Petersburg the next day. With his lines broken, Lee began retreating west towards his eventual surrender at Appomattox on April 9. For its role in keying the final movements of the war in the East, Five Forks is often referred to as the Waterloo of the Confederacy.

Implication of implementing BIS in Abu Dhabi police department ..(ERP) Essay

Implication of implementing BIS in Abu Dhabi police department ..(ERP) enterprise resource planning - Essay Example These subsystems and the information they contain include: Traditional financial performance metrics provide information about the past performance of an organization but are not particularly suited for predicting future performance. By taking into account factors other than financial ones, the management of a company can convert the company’s strategy into practically achievable goals and assess how well the strategic plan is being carried out. An organization has to devise strategies and do careful planning before implementing ERP techniques. ERP helps to reduce costs and enhance the quality (efficiency) of working time. ERP techniques help maximize the value of technological advancements and align their utilization to the goals of the organization. For example, ERP enables a manager in the Sales Department to answer a customer query immediately by seeing the real-time status of the customer’s product delivery, which would not have been possible otherwise. ERP techniques have facilitated organizations’ ability to do away with tedious and time-consuming processes (Ptak & Schrgenheim,2003).Enterprise software is built around a large number of predefined business practices based on best practices. Best practices are the most successful solutions or methods of solving problems an organization uses for regularly and effectively achieving business goals. Enterprise systems help increase efficiency and help mangers make better decisions by providing them updated information from throughout the firm. It also helps form a more ‘customer-driven’ organization by facilitating faster responses to customer queries and requests for information. A variety of factors, such as globalization, rapid innovation, deregulation and technological advances, increasing competition and dynamic changes in the market, have forced many organizations to rethink how they can gain competitive

Midterm exam Essay Example | Topics and Well Written Essays - 750 words

Midterm exam - Essay Example It is on this account that men will use their positions and wealth to influence vulnerable women to have sex with them, only to abandon them later once they have satisfied their lust regardless of the consequences of their actions, which may include unplanned pregnancies. As such, allowing abortion becomes a key element towards protecting poor women from becoming single parents without intent as well as reducing poverty and street crime. A child deserves to have a better life i.e. access to quality education, healthcare, good nutrition among other basic necessities such as shelter and clothing. Apparently, a poor mother, who cannot even sustain herself, has nothing to offer her child and this implies that families built on this sort of foundation eventually has a high probability of becoming a liability to the society and the government at large. In fact, these are the people who unfortunately end up in the streets begging for assistance as well as conducting heinous acts such as pro stitution and robbery. In this light, abortion enables one to exercise her right to decide on the best time to become a parent, when she has accumulated all the necessary courage and economic stability to sustain herself as well as her offspring (Heary 22). Most of the societies set considerably high moral standards, which prohibit fornication alongside other irresponsible sexual behaviors such as prostitution and adultery. For example, the church has always advocated for celibacy as a natural method of solving dilemmas such as HIV/AIDS among other sex related issues (Beckwith 108). This has influenced greatly the way the society perceives those unfortunate persons who intentionally or otherwise find themselves in these predicaments such as pregnancies out of wedlock. These people are discriminated against as they are perceived to be immoral and therefore, a shame to the society and the families which they come from. Some of the societies will even exclude them from their affairs fo r it will be apparent that they are a bad influence and bad examples to their age mates as well as the generation below them. To avoid all this, it would be of great significance to abort the child in order to maintain the level of standards expected by the society, by concealing sexual involvement. Abortion is also a way of controlling high population growth. In this case, it would be necessary to point out that I come from China, a country which is categorized as one with the highest population, of approximately 1.3 billion people, and which is expected to rise to approximately 1.6 billion people by the year 2025 (Beckwith 109). Due to this, the country has set up a one child policy, in order to slow down the rate of births. However, it has been noticed that there are those who fail to observe this policy, and goes ahead to have more than one child, especially in the rural areas, where analysts indicate that there is the culture whereby couples prefer the birth of boys as opposed to girls, mainly due to inheritance issues. In this context, if the first child is a girl, the parents cannot rest there for they will definitely have no heirs to their property and therefore, they have to bear more children until that time when a baby boy is born. It has been noted that such couples usually lie during census so as to protect themselves from facing the

Introduction To Dc Dc Converter Engineering Essay

Introduction To Dc Dc Converter Engineering Essay ABSTRACT A bidirectional dc-dc converter is used for dc-dc power conversion applications. The power converter includes two full bridge converters This Bidirectional dc-dc converter is best for electrical vehicle applications. A bidirectional, isolated topology is proposed in consideration of the differing fuel cell characteristics from traditional chemical-power battery and safety requirements. The topology proposed in the paper has advantages of simple circuit with soft switching implementation without additional devices, high efficiency and simple control. INTRODUCTION TO DC-DC CONVERTER: DC-DC converters are devices which change one level of direct current/ voltage to another (either higher or lower) level. They are primarily of use in battery-powered appliances and machines which possess numerous sub circuits, each requiring different levels of voltages. A DC-DC converter enables such equipment to be powered by batteries of a single level of voltage, preventing the need to use numerous batteries with varying voltages to power each individual component.   1.1. BUCK-BOOST CONVERTER Fig. 1: schematic for buck-boost converter With continuous conduction for the Buck-Boost converter Vx =Vin when the transistor is ON. When the transistor is OFF the inductor in trying to maintain the current in the same direction reverses its polarity as a result of which the diode is forward biased and Vx =Vo. For zero net current change over a period the average voltage across the inductor is zero. Fig. 9: Waveforms for buck-boost converter Vin ton + Vo toff = 0 which gives the voltage ratio and the corresponding current Since the duty ratio D is between 0 and 1 the output voltage can vary between lower or higher than the input voltage in magnitude. The negative sign indicates a reversal of sense of the output voltage.   CONVERTER COMPARISON The voltage ratios achievable by the DC-DC converters is summarised in Fig. 10.We can notice that only the buck converter shows a linear relationship between the control (duty ratio) and output voltage. The buck-boost can reduce or increase the voltage ratio with unit gain for a duty ratio of 50%. Fig. 10: Comparison of Voltage ratio 1.3 BI-DIRECTIONAL DC-TO-DC CONVERTER A DC-DC converter which can be operated alternately as a step-up converter in a first direction of energy flow and as a step-down converter in a second direction of energy flow is disclosed. Potential isolation between the low-voltage side and the high-voltage side of the converter is achieved by a magnetic compound unit, which has not only a transformer function but also an energy storage function. The converter operates as a push-pull converter in both directions of energy flow. The DC-DC converter can be used for example in motor vehicles with an electric drive fed by fuel cells. A bi-directional converter for converting voltage bi-directionally between a high voltage bus and a low voltage bus, comprising a switching converter connected across the high voltage bus, the switching converter comprising first and second switching modules connected in series across the high voltage bus, a switched node disposed between the switching modules being coupled to an inductor, the inductor connected to a first capacitor, the connection between the inductor and the first capacitor comprising a mid-voltage bus, the first and second switching modules being controllable so that the switching converter can be operated as a buck converter or a boost converter depending upon the direction of conversion from the high voltage bus to the low voltage bus or vice versa; the mid-voltage bus being coupled to a first full bridge switching circuit comprising two pairs of series connected switches with switched nodes between each of the pairs of switches being connected across a first wi nding of a transformer having a preset turns ratio; and a second full bridge switching circuit comprising two pairs of series connected switches with switched nodes between each of the pairs of switches being connected across a second winding of the transformer, the second full bridge switching circuit being coupled to a second capacitor comprising a low voltage node. 1.3.3 WORKING OF DC-DC Converters In its simplest form, a DC-DC converter simply uses resistors as needed to break up the flow of incoming energy this is called linear conversion. However, linear conversion is a wasteful process which unnecessarily dissipates energy and can lead to overheating. A more complex, but more efficient, manner of DC-DC conversion is switched-mode conversion, which operates by storing power, switching off the flow of current, and restoring it as needed to provide a steadily modulated flow of electricity corresponding to the circuits requirements. This is far less wasteful than linear conversion, saving up to 95% of otherwise wasted energy. 1.3.2 BIDIRECTIONAL DC-DC CONVERTERS TOPOLOGIES There are many circuit topologies for bidirectional dc-dc converter. Some of them are Non isolated (Without transformer): Full bridge bidirectional dc-dc converter (shown in fig) Half bridge bidirectional dc-dc converter II. Isolated (with transformer): Full bridge bidirectional dc-dc converter ( shown in fig) Half bridge bidirectional dc-dc converter 1.3 NON-ISOLATED BIDIRECTIONAL DC-DC CONVERTER: Fig2: Full bridge bidirectional dc-dc converter Fig 17 shows a basic circuit diagram of a full bridge bidirectional DC-DC converter. It has interleaved operation for both boost and buck modes It has smaller passive components It has less battery ripple current 1.3.2.2 ISOLATED BIDIRECTIONAL DC-DC CONVERTER (PROPOSED CONVERTER): Fig18: lv-side current source and hv-side voltage source Fig 18 shows the circuit diagram of an Isolated DC-DC converter. This converter has the following features Simple voltage clamp circuit implementation Simple transformer winding structure and low turns ratio High choke ripple frequency (2fs) Start up problem will be present in this circuit 1.4 SEMICONDUCTOR SWITCHING: Semi conductor switching are of two types. They are 1. Hard Switching 2. Soft Switching 1.4.2 SOFT SWITCHING More recently, new power conversion topologies have been developed which dramatically reduce the power dissipated by With soft switching techniques, reduction in wasted power will often improve the efficiency of a unit by more than 2%. While this does not sound significant, it can account for a saving of more than 20 W in a 1000 W power supply. This 20 W is power that would have been dissipated by the main power transistors, the most critical and most heavily stressed semi-conductors in any switch mode power supply. Reducing the power here lowers their junction temperature, giving increased thermal operating margins and, hence, a longer life for the power supply. Not only does a soft switching power supply generate significantly less electrical noise, it achieves greater efficiency, longer mean time between failures (MTBF), and higher immunity to the effects of other equipment operating nearby. It is desirable for power converters to have high efficiencies and high power densities. Packaging and cost limitations require that the converter have a small physical size and weight. Power density and electrical performance are dependent on the switching frequency as it determines the values of the reactive components in the converter. Thus, high frequency operation of the converter is highly desired. However, operation at high frequency results in higher switching losses and higher switching stresses caused by the circuit parasitics (stray inductance, junction capacitance). The circuit topology of the proposed bidirectional isolated converter is shown in Fig. According to the power  ¬Ã¢â‚¬Å¡ow directions, there are two operation modes for the proposed converter. When power  ¬Ã¢â‚¬Å¡ows from the low-voltage side (LVS) to the high-voltage side (HVS), the circuit operates in boost mode to draw energy from the battery. In the other power  ¬Ã¢â‚¬Å¡ow direction, the circuit operates in buck mode to recharge the battery from the high-voltage dc bus. Based on the symbols and signal polarities introduced in Fig. 2, the theoretical waveforms of the two operation modes are shown in Fig. (a) and (b), respectively. Fig42: Theoretical waveform under (a) boost and (b) buck operation Boost Mode (Discharging Mode) Operation When the dc bus voltage in the HVS is not at the desired high level, such as during a cold start, the power drawn from the low-voltage battery flows into the high-voltage dc bus. During this mode, the proposed converter is operated as a current-fed circuit to boost the HVS bus voltage. The LVS switches Q1, Q4 and Q2, Q3 operate at asymmetrical duty ratios and 1- which require a short overlapping conduction interval. Referring to the equivalent circuits for the boost mode operation in Fig. 43, the detailed operating principle can be explained as follows. Although the LVS switches subject to higher voltage stress, this is an advantage because the battery voltage is low. Because the overlapping interval for the LVS switches Q1, Q4 and Q2, Q3 is very short, the LVS transformer current flows through only one LVS switch at most time. Thus, the conduction losses for Q1, Q4 and Q2, Q4 can be greatly reduced to improve the conversion efficiency. Moreover, the LVS circuit produces a relatively ripple free battery current that is desirable for the low voltage battery. The voltage transfer ratio Mboost for the boost mode operation for the proposed dc-dc converter can be derived from the volt-second balance condition across the inductor L1 represented by (7). The current stresses of the inductor windings can be also determined as (6).The inductances of the power inductor L1 can be determined for their given peak-to-peak current ripples, ΆI1 Where ÃŽÂ » (%) is the ripple percentage of the inductor currents IL1 B. Buck Mode (Charging Mode) Operation Different from the traditional electric vehicle driving system, the fuel cell powered system needs an additional energy storage device to absorb the feedback power from the electric machine. This energy storage device may be a lead-acid battery as shown in Fig44 . The proposed circuit works in buck mode to recharge the battery from high-voltage dc bus. During this mode, the proposed converter is operated as an asymmetrical half bridge circuit with synchronous rectification current doubler to recharge the battery from high-voltage dc bus. The HVS switches Q5, Q8 and Q6, Q7 operate at asymmetrical duty ratios and 1- which require short and well-defined dead time between the conduction intervals. Referring to the equivalent circuits in Fig. , the detailed operating principle of this mode can be explained as follows. Fig44: modes of operation in buck mode While the LVS switches, Q1, Q4 and Q2, Q3, share unequal voltage and current stresses, the HVS switches, Q5, Q8 and Q6, Q7, share equal voltage stresses as (8). Then the current stresses of the HVS switches can be found as DESIGN CONSIDERATIONS FOR KEY COMPONENTS To verify the feasibility of the proposed scheme, a 2-kW laboratory prototype operated at 20 kHz was built. The simulation and experimental results will be shown and discussed in the next section. The LVS of the design example was connected to a 12-V lead-acid battery whose terminal voltage could swing from 10-15 V. The nominal voltage on the HVS dc bus was designed to 300 V, with an operating range from 150-400 V. The design considerations Based on (5), the turn-ratio selection of transformer can be calculated as (15). The HVS device ratings can then be calculated using (8)-(10) as follows: B. Power Inductors Let the peak-to-peak current ripples be 20% of the inductor currents under full power. The current rating and the inductance of the power inductor L1 can be determined using (6)- (7) as follows: Because of the ripple cancellation on the battery current, a larger ripple current in inductor L1 and can be allowed in practical applications. Thus, the inductance and the size of the inductors L1 might be smaller. To verify the theoretical operating principles, a 2-kW design example was simulated by using MATLAB. There is a good agreement between the simulation results and theoretical analysis. In this research, a 2-kW laboratory prototype was implemented and tested to evaluate the performance of the proposed bidirectional isolated dc-dc converter.. The ripple cancellation between two inductor currents can be observed. This is desirable for a low-voltage battery. 7.1 BOOST OPERATION FOR BIDIRECTIONAL DC-DC CONVERTER CONVENTIONAL CIRCUIT FOR BOOST MODE 7.3 RESULTANT WAVE FORM: 7.3.1 BOOST OPERATION Input and Output waveform: Fig 48 CONVENTIONAL CIRCUIT FOR BUCK MODE Fig47 7.4 RESULTANT WAVEFORM FOR BUCK OPERATION : Input and Output voltage waveform Fig 49 Proposed Bidirectional DC-DC converter Input and Output Voltage Waveforms: Fig50 Fig 51 Inductor Current Waveforms: Fig52 CONCLUSION A soft-switched isolated bidirectional dc-dc converter has been implemented in this paper. The operation, analysis, features and design consideration were illustrated. Simulation and experimental results for the 45W, 20 kHz prototype was shown as per principle. It is shown that ZVS in either direction of power flow is achieved with no lossy components involved As results, advantages of the new circuit including ZVS with full load range, decreased device count, high efficiency (measured more than 94% at rated power), and low cost as well as less control and accessory power needs, make the proposed converter very promising for medium power applications with high power density.