Nucor Corporation Case Essay

Summary: For more than 20 years the Nucor Corporation has been one of the leading manufacturers of steel and steel related products in the world. With their technology advancement, low debt ratio, decentralized type of organization and many more, this company still thrives to achieve better goals in their company. Aside from the positive views of the company, it also faced problems like bankruptcy. (te pakidagdagan n lng) History: Nucor traced its origins to auto manufacturer Ransom E. Olds, who founded Oldsmobile, and later, Reo Motor Cars. Through a series of transactions, the company eventually became the Nuclear Corporation of America, a company involved in the nuclear instrument and electronics business. In 1972, the firm changed its name to Nucor Corporation. By 1998, it had become America’s second-largest steel maker. Operations: Nucor related its diverse facilities in rural areas across the United States, establishing strong ties to its local communities and its work force. As a leading employer with the ability to pay top wages, it attracted hard-working, dedicated employees. These factors also allowed Nucor to select from among competing locales, siting its operations in states with tax structures that encouraged business growth and regulatory policies that favored the company’s commitment to remaining union-free. By mid-2008, Nucor operated 53 facilities throughout the United States and one in Point Lisas, Trinidad. The company also maintained operations through wholly owned subsidiaries, Harris Steel and the David J. Joseph Company (DJJ). Strategy: Nucor’s strategy focused on two major competencies: building steel manufacturing facilities economically and operating them productively. Organization Structure: Compared to the typical Fortune 500 company with 10 or more management layers, Nucor’s Structure was decentralized, with only the four management  layers illustrated below: Chairman / Vice Chairman / President Vice President / Plant General Manager Department Manager Supervisor Human Resource Policies: Employee relations at Nucor were based on four principles: 1. Management is obligated to manage Nucor in such a way that employee will have the opportunity to earn according to their productivity. 2. Employees should feel confident that if they do their jobs properly, they will have a job tomorrow. 3. Employees have the right to be treated fairly. 4. Employees must have an avenue of appeal when they believe they are being treated unfairly. Compensation: Nucor provided employees with a performance-related compensation system. All employees were covered under one of four compensation plan, each featuring incentives for meeting specific goals and targets. 1. Production Incentive Plan * employees directly involved in manufacturing were paid weekly bonuses based on actual output in relation to anticipated production tonnages produced. The bonuses were paid only for work that met the quality standards and were pegged to work group, rather than individual output. 2. Department Manager Incentive Plan * Department managers earned an annual incentive bonus based on the performance of the entire plan to which they belonged. The targeted performance criterion here was return on assets. 3. Non-Production and Non-Department Manager Incentive Plan * All employees not in the Production Incentive Plan or Department Manager Incentive Plan – including accountants, engineers, secretaries, clerks, and receptionists – received a bonus based primarily on each plant’s return on assets. It could total over 25% of an employee’s base salary. 4. Senior Officers Incentive Plan * Included all corporate executives and plant general managers. A portion of pre-tax earnings was placed into a pool that was divided among the officers. If Nucor did well, the officers’ bonuses, in the form of stock (about 60%) and cash (about 40%), could amount to several times their base salaries. If Nucor did poorly, an officer’s compensation was only base salary and, therefore, significantly below the average pay for this level of responsibility. Information Systems: Benefits: Nucor took an egalitarian approach toward employee benefits. Nucor’s benefit program also attested to the company’s commitment to education. Technology: Nucor did not have a formal R&D department, a corporate engineering group, or a chief technology officer. Instead, it relied on equipment suppliers and other companies to do the R&D, and they adopted the technological advancements they developed – whether in steel or iron making, or in fabrication. Teams composed of mangers, engineers, and machine operators decided what technology to adopt. Future: The company’s biggest challenge (in the future) is to continue to grow the company at 15 – 20% per year, and to keep earnings parallel with its growth. Analysis: Nucor Corporation became one of the top corporations in the steel industry because of their handwork and technology innovation. This company also sees and takes care of its employee’s needs, which in return gives them  a quality service in their work. Conclusion: Nucor, even though we can see it as a successful, almost perfect company, still faces problems like other businesses in the industry. Problem: The company has lost one-third to one-half of its market value when the stock reached its peak value (mid-2008), and has not recovered as of 2012. Recommendation: We can recommend change in the company’s technology, like getting more advance equipments in making steel and steel-related products. Or the company could make a merger to other company to utilize its resources to its maximum while keeping cost low.

History of Physical Education

Brief History of Physical Education A brief history of physical education in the United States would kick off in the nineteenth century. There was growing popularity of formal physical education programs all across Europe where calisthenics and gymnastics were all the rage. American schools looked to follow the European model by incorporating physical education into the curriculum for primary and secondary schools. And a brief history of physical education would not be complete with a consideration of institutes of higher education that gradually built up extremely successful sports programs.How it began The brief history of physical education would start in just about 1820 when schools focused on gymnastics, hygiene training and care and development of the human body. By the year 1950, over 400 institutes had introduced majors in physical education. The Young Men's Christian Association launched its very first chapter in 1851 and focused on physical activities. Colleges were encoura ged to focus on intramural sports particularly track, field and football.But physical education became a formal requirement following the civil war when many states opted to pass laws that required schools to incorporate a substantial physical education component into their curriculums. But it was not till 1970 that an amendment was made to the Federal Education Act that allowed women from high school and college to compete in athletic competitions. Sex-based discrimination was completely outlawed from government funded programs at this point. THE HISTORY OF PHYSICAL EDUCATION AND ADAPTED PHYSICAL ACTIVITY IN GREECEIn Greece the latest years special education has followed the same progression as in any other country in Europe but in a very slow pace. Specifically, Special Education services were available to Greek children since the beginning of the 20th century, adapted Physical Education was introduced the last two decades. After the first half of the century various associations developed intense activity with the aim to protect specific groups of people with special needs such as, the blind, the deaf and motionaly disabled.The initiative had clearly charitable characteristics with pity as the main feeling. The state welfare was non-existent every kind of care and prevention was accorded to the authorization of the charitable organization that with full power decided during the course of the years about the life and the future of thousands of people with special needs. The offers of the individuals had the form of institutional care (enclosed protection) with the offer of basic knowledge.The interest of private initiative led to the introduction of various institutional units and schools; firstly in the area of Attica and then in other cities of Greece. Some of the first institutions, which were created, was the â€Å"house of the blind† in 1906, the â€Å"house of the deaf and dump† in 1923, and the â€Å"Hellenic organization for the protec tion and rehabilitation of disabled children†. In 1937 much late there were more branches created such as the â€Å"national institution for the protection of the deaf and dump† in 1937, the â€Å"lighthouse of the blind† in 1946, the â€Å" school of the blind in North Greece† in 1948 etc.These institutions housed a great number of children but the role of the individuals was not only always a charitable one. However, the private sector helped in its way the state preparation so as to take up later the responsibility and interfere institutionally. The first state interferences began in 50’s and concerned mainly legislation arrangements for the blind and after for the motionaly disabled. The state however was interested in the group of the mentally retarded children and later in the motionaly disabled, which the private agents had completely ignored.The first school, which was founded by the state for the mentally retarded children, was the â€Å" original special school of Athens† in 1937. Many people considerthe state interference in the space of special education during the 30’s non-occasional. The considerable evolutions of pedagogical and psychology sciences, the establishment of obligatory attendance for all the children and the great number of mentally retarded children comparatively with other groups of â€Å" inferior individuals† was a reality which the Greek state could not ignore.From the mid of 50’s the 70’s the developments in special education came again from the wide activity of the private sector while the state followed with mainly legislation inferences and the well known sympathy towards the people with special needs. So, during this period educational units were founded and â€Å"deaf and dumb† schools in various areas of Greece and units for motionaly-disabled people. Another offer of the private sector was the foundation of children’s neuropsychiatry clini cs and schools for the group of â€Å"marginal adults† and â€Å" mentally retarded children†.The exemplification of the Greek state and the educational policy of the western countries begins in the mid of the 70’s approximately. Specifically towards the end of the 70’s measures were promoted for the professional rehabilitation of the disabled by giving motives to employers for the employment of these people. Since 1980 and then special classes for the children with, learning difficulties and slight mental retardment began to be estamplished.The Greek state in the 80’s seems to desire to participate actively with the other social factors in an attempt of reorganization of the philosophy and pre-existent structure concerning the people with special needs, which imposed their life and social back round. Precisely, emphasis was given in the whole development and the development of the potential of the people with special needs, their introduction in t he productive procedure and their mutual acceptance in the social group.Today, thousands of individuals with disabilities are introduced to sports in various settings such as schools or in sports clubs in both segregated and integrated settings by a variety of national and international organizations. The momentum for such change is contributed to several reasons: †¢ One of the most important reason is the introduction and approval of a new law, which mandates not only free public education for all children, but most important integration of children with disabilities in schools settings.This law is consideredas a springboard for the recognition for all children’s rights to participate in physical education activities. †¢ A second reason, is beginning of 90’s the implementation of the program â€Å"Sports for All†, which is organized by the General Secretariat of Sports and implemented with the support of different municipalities within Greece. †¢ A third reason, is the mandatory exposure of all students of physical education in adapted physical activity course work during their core university studies.In this way they have the opportunity not only to be introduced, but also to become specialized later on this subject. This has considerably affected their attitude to teach integrated sports. †¢ A fourth reason is the organization of the Paralympic Games of 2004, which is considered one of the largest events in the world. Due to the magnitude of this event, Greece started to evaluate the current status of the movement for sports for the disabled people, as well as, begin to take important actions towards the best organization of the games. History of Physical Education PREFACE To provide a meaningful background of physical education and sport in modern society it is helpful to have a clear understanding of its role in the past and how it emerged. The purpose of this assignment is to outline the history of physical education since time immemorial. The text begins with the beginning of the humankind engaging in physical activities, showing the history of physical education and sport being a rich tapestry of people, places, events and social forces from early civilization to the present time through transitional periods. INTRODUCTIONThe ground of education as a whole is going through remarkable challenges to serve the needs of the individual and the society, and this trend is reflected in physical education also. The history of physical education goes back to the earliest times, if we think of it in the simple terms of fitness and has existed since human society in one form or other. Since early history, even before the dawn of civilization and cultur e, physical exercise has been a very important aspect of human existence and it was not so long ago that it was called† physical culture† or â€Å"physical training†.THE PALEOLITHIC PERIOD Primitive humans began life in the â€Å"Stone Age. † What can they be called? Paleolithic people, Stone agers, primitive humans or cave men. They were hunters and gatherers. They hunted wild game and fished; they gathered veggies, berries and nuts. Primitive humans depended entirely on nature for food. Primitive men moved according to their satisfaction, needs and necessity. They needed to be fit to be able to go through their journey to hunt for food and water. Being nomads and hunters, they were people who had to be persistently hunting and gathering food for survival.Their trips regularly lasted for one-to-two days for food or water and were meant for regular physical activity to be produced. When they successfully hunted, they would travel many miles and miles to cel ebrate with family and friends. Physical activities were not organized by them. The necessity for survival which is the protection against hostile environment and wild beasts, and sometimes the engagement in murder to insure their protection, motivated these men to keep themselves physically ? t and strong enough compared to stronger forces of nature. In those days there were no machines to help people in their work.That is why they had to depend exclusively upon their physical powers and physical skill. They considered their body to be their prize possession, so their primary concern was to maintain and protect their body. The order of the day was the survival of the most fit. Their sociable nature was inborn and drew only by mating and propagation that gave them the desire to dance and play, which were not being organized. Men lived in such a state for thousands of years. There was neither any organization nor system. Most of their acts were learnt by the young generations by the competence of imitation rather than instruction.This lifestyle created many physical activities and a high level fitness which defined human life. THE NEOLITHIC TRANSITION Neolithic people lived during the â€Å"New Stone Age†, from 9000 to 8000 B. C. This was the transitional period in which pre- historic societies began to control their surroundings and form civilization. The two most significant developments were the domestication of animals and farming. Their society was different from Paleolithic culture because they lived in established communities, domesticated animals and cultivated crops.As they improved their society they developed skills like spinning, weaving and building. They also made tombs and religious items. Men and women gave up hunting gathering as the only sources of living and learnt to produce their own food. Agriculture and the raise of cattle were discovered and increased to a productive economy. Many villages were built generally located next to rive rs. Then came the creation of the plow, so the difficult tasks being done by the animals and other agricultural development brought the beginning of a less active lifestyle.Social organization became more complex in the first villages, and then towns. Different kind of chiefs appeared and gave rise to a political system. There was class system whereby society was divided into rich and poor. A specialization of work took place. Apart from peasants and cattle farmers, new economical activities such as craftsmanship (fabric, pottery) were born. This era in history symbolizes the beginning of a more sedentary lifestyle, as man began to lessen some hardships of life while simultaneously decreasing daily physical activity.ANCIENT CIVILIZATIONS (2500-250 B. C. ) (i) China In China, the participation of regular physical activity was encouraged by the philosophical teachings. There were no such words in the Chinese vocabulary entirely corresponding to the Western terms of â€Å"sport† and â€Å"physical education†. Such physical exercises as wrestling, swordplay, archery, charioteering and horse-racing were all incorporated in the military training and therefore came under the general term of â€Å"wuyi,† or â€Å"martial arts. † Kung Fu gymnastics was developed to keep the body in good and working condition.It consisted of various stances and movements, patterned by separate foot works and imitations of different kind of animals’ fighting styles. (ii) India India has a long recorded history of civilization but physical activity was not encouraged because of the religious teachings over there. The teachings of Buddha restricted most of the sports and games practiced by other early civilizations. However, an exercise programs known as â€Å"yoga†, same as the Chinese Cong Fu gymnastics, was developed and some other physical activities as well. According to the Hindu priests, Yoga signifies the development of body, mind, and spir it.The Ancient Indian philosophers recognized the health benefits of Yoga, which consisted of the proper functioning of organs and the whole well-being. There have been many physical activities but were never treated as a part of general education, they were mostly an entry to military career. ANCIENT GREECE: THE HEART OF PHYSICAL EDUCATION & SPORT (2500-200 B. C. ) The western civilization began with the Greeks. They were the first one to provide a methodical and philosophical attitude toward education, physical education and sport. It is believed that no other civilization has held fitness in such appreciation as the ancient Greece had.The admiration for beauty of the body and importance of health and fitness throughout society is one that is beyond compare in history. For the Greeks, the development of the body was equivalently as important as development of the mind. They believed that the physical well-being was crucial for the mental well –being. During that period, the Greek states were frequently at war with each other. The Fighting abilities were very much associated with physical fitness levels, therefore making it very important for the people to maintain high level of fitness.Athens and Sparta were the two most famous city-states and dominant force of the Greek civilization. Sparta was already militaristic by 700 B. C. Spartans were derisive of intellectualism. They were generally suspicious and conventional. All that mattered to the Spartans was being a warrior. Athens was the more democratic of the two city-states. Both city-states served the people and their needs although they were very different. Being a potential warrior was all that mattered to the Spartans. Athens was the more democratic of the two city-states. SPARTAThe Spartan system was much more autocratic. Male children were taken at the age of seven to learn the basic military skills while living in barracks. Little emphasis was placed on the arts, sciences, philosophy and lite rature. Physical activities such as gymnastics, running, jumping, boxing, wrestling and pankration (a brutal combination of  boxing and wrestling) were provided to produce powerful warriors. When the children reached the age of fourteen, they were taught group fighting tactics which would allow them to succeed while in the military from the ages of twenty to thirty.Girls did not live in public military  barracks like the boys, but they participated in discuss, gymnastics, horse riding,  javelin, swimming, running, and wrestling at separate training grounds. The objective for women’s physical education was to enable them to produce healthy and strong potential warriors. At the age of thirty, the men could then marry women who were fit and healthy so that they could make strong babies, therefore future warriors. ATHENS For the Athenian -The motto for education was â€Å"a sound mind in a sound body† (mens sana in corpore sano) Athens was quite different compared to the Sparta.The Athenian culture was a very much more freethinking and democratic society specially noted for its art, literature, philosophy as well as its political system. There were citizens, foreign settlers and slaves but only the citizens were provided with educational opportunities. When compared to Sparta, education was very different in Athens. Women had no physical education compared to Sparta. They put much more emphasis toward intellectual quest. Their objective was similar to Sparta that is preparing male warriors.Athenian education was a balance between music (including poetry) and gymnastics which enveloped a range of physical activities. Physical education was provided to the students with a series of graded activities at the Palestra, which consisted of an indoor facility for gymnastics, and to an outdoor space for boxing, discus, javelin, running, jumping, pankration, pentathlon and wrestling. Many of these athletic events were part of the four great sport and rel igious festivals which consisted of the Olympic, Isthmian, Pythian and Nemean Games.These games started as simple athletic contests dedicated to Greek gods, but the Olympic Games, in particular, over 1000 years, became increasingly complex encompassing events for boys and men in running over different distances, pentathlon, wrestling, races in armour, chariot races, and pankration. As of education more broadly, the clear objectives of physical education in Athens were to educate the mind and the body and to produce a well integrated person. ROMANS The political ambition of Rome incorporated physical education into a national program for the preparation of military.Therefore, similar to the Greeks, sports, games and physical recreation were meant to prepare boys and young men for military service. Physical education for the Romans was about athletics, which was entertainment above all. All Roman citizens between the ages of 17 and 60 had to be fit for the military service, so it was very important for all the citizens to maintain good physical condition and be prepared. Military training consisted of activities such as running, marching, jumping, and discus and javelin throwing. The fitness levels of the general Roman population declined as individuals became attracted to wealth and entertainment.People were forced to fight to the death, and oftentimes fed to lions. Women were not as marginalized in Rome as they were in Greek city-states. Some sporting events were organized for young women such as swimming, dancing, and light exercise was common, especially among the privileged classes. THE DARK (476-1000) AND MIDDLE AGES (900-1400) The Middle Ages saw the fall of the Roman Empire which was conquered by Barbarians from Northern Europe, whereby the lavish lifestyles of the Romans had resulted in the complete decay of the society's fitness level.There was the rise of Christianity, and the Christian’s influence brought about a denial of physical activity fo r anything other than manual labor. They viewed physical play as immoral, so they halted the Olympic Games in 394. The barbarians from Northern Europe were similar to the primitive humans. Their way of life consisted of hunting and gathering food, so physical activity and fitness were fundamentals for survival. Thus, despite the downfall of the Roman Empire, fitness experienced a revival during the Dark and Middle ages because survival during these challenging times required it. THE RENAISSANCE (1400-1600)During the Renaissance, a renewed appreciation for human life evolved creating an environment which was ready for the widespread development of physical education; revival of ancient Greek ideals throughout Europe. There were many people which included the religious leader;Martin Luther, the philosopher; John Locke, physical educators; Vittorino da Feltra, John Comenius, and Richard Mulcaster carried on that high fitness levels improved intellectual learning. But in the 1600s peopl e believed that if it did not have any specific purpose than just a waste of time. PHYSICAL EDUCATION AS FROM THE 1700SThere was a big change in physical education during the 1700’s which can be mostly accredited to three people: Jean Jacques Rousseau, Johan Simon, and Guts Muths. Rousseau was the first person to promote education for the people and he also concluded play as being educational and stressed the importance of physical education to the development of a strong body. In the mid 1700s, Johan Simon became the first physical education teacher and stressed on the fact that physical education should be taught along with reading and writing. Simon believed physical education should include a lot of physical effort.Guts Muths developed a series of gymnastic apparatuses and believed that very important social skills are developed through physical education. These people of that time and the things they did began to pave the road to where we are today. In 19th-century, the first indoor gymnasium was built in Germany and some countries such as Europe, Sweden and Germany developed systems of gymnastics that were adopted internationally. A gymnasium was also build in Finland where exercise was for the first time seen as a way to achieve physical treatment. In connection to exercise, students started to study anatomy and physiology.Denmark was among the first countries to require physical education in schools. By the 1820s, some American schools offered gymnasium and physical education. The physical education included the development and care of the body, and training in hygiene, callisthenic exercises, gymnastics, and the performance and management of athletic games. CONCLUSION Physical education has a cultural heritage and background which started at the dawn of civilization. Primitive human being had to be very active and physically to survive. Farming began in its primitive form and made people have more physical activity from only working in the fiel ds.People fitness levels changed here and the also began seeing a more sedentary lifestyle. Ancient Greek culture depended upon preparing its young men for war. Training for battle was not an option, but a prerequisite. Ancient physical education programs concentrated exclusively on activities that trained soldiers. The significance of physical education no longer concentrates solely on training soldiers for battle and ancient athletes for victories but for the wholesome development of a person. It began in ancient Greece and made its way around the world. REFERENCES S. E. Smith. (). What was the Neolithic Period?. Available: http://www. isegeek. com/what-was-the-neolithic-period. htm. Last accessed: 30th Oct 2012. Charles A. Bucher. (1983). Historical foundations of physical education and sport. In: Nancy K. Roberson Foundations of physical education and sport. US: The C. V. Mosby Company. P133-155. http://www. cals. ncsu. edu/agexed/aee501/rousseau. html http://prezi. com/ieokiwmd e3ni/history-of-physical-education/ Howel et al. 1994. History Of Sport And Physical Education. In: Foundations of Physical Education,pp. 17-117 A. Bruce Frederick. (). Gymnastics. Available: http://www. britannica. com/EBchecked/topic/250277/gymnastics#ref700589. Last accessed: 01st nov 2012. History of Physical Education Brief History of Physical Education A brief history of physical education in the United States would kick off in the nineteenth century. There was growing popularity of formal physical education programs all across Europe where calisthenics and gymnastics were all the rage. American schools looked to follow the European model by incorporating physical education into the curriculum for primary and secondary schools. And a brief history of physical education would not be complete with a consideration of institutes of higher education that gradually built up extremely successful sports programs.How it began The brief history of physical education would start in just about 1820 when schools focused on gymnastics, hygiene training and care and development of the human body. By the year 1950, over 400 institutes had introduced majors in physical education. The Young Men's Christian Association launched its very first chapter in 1851 and focused on physical activities. Colleges were encoura ged to focus on intramural sports particularly track, field and football.But physical education became a formal requirement following the civil war when many states opted to pass laws that required schools to incorporate a substantial physical education component into their curriculums. But it was not till 1970 that an amendment was made to the Federal Education Act that allowed women from high school and college to compete in athletic competitions. Sex-based discrimination was completely outlawed from government funded programs at this point. THE HISTORY OF PHYSICAL EDUCATION AND ADAPTED PHYSICAL ACTIVITY IN GREECEIn Greece the latest years special education has followed the same progression as in any other country in Europe but in a very slow pace. Specifically, Special Education services were available to Greek children since the beginning of the 20th century, adapted Physical Education was introduced the last two decades. After the first half of the century various associations developed intense activity with the aim to protect specific groups of people with special needs such as, the blind, the deaf and motionaly disabled.The initiative had clearly charitable characteristics with pity as the main feeling. The state welfare was non-existent every kind of care and prevention was accorded to the authorization of the charitable organization that with full power decided during the course of the years about the life and the future of thousands of people with special needs. The offers of the individuals had the form of institutional care (enclosed protection) with the offer of basic knowledge.The interest of private initiative led to the introduction of various institutional units and schools; firstly in the area of Attica and then in other cities of Greece. Some of the first institutions, which were created, was the â€Å"house of the blind† in 1906, the â€Å"house of the deaf and dump† in 1923, and the â€Å"Hellenic organization for the protec tion and rehabilitation of disabled children†. In 1937 much late there were more branches created such as the â€Å"national institution for the protection of the deaf and dump† in 1937, the â€Å"lighthouse of the blind† in 1946, the â€Å" school of the blind in North Greece† in 1948 etc.These institutions housed a great number of children but the role of the individuals was not only always a charitable one. However, the private sector helped in its way the state preparation so as to take up later the responsibility and interfere institutionally. The first state interferences began in 50’s and concerned mainly legislation arrangements for the blind and after for the motionaly disabled. The state however was interested in the group of the mentally retarded children and later in the motionaly disabled, which the private agents had completely ignored.The first school, which was founded by the state for the mentally retarded children, was the â€Å" original special school of Athens† in 1937. Many people considerthe state interference in the space of special education during the 30’s non-occasional. The considerable evolutions of pedagogical and psychology sciences, the establishment of obligatory attendance for all the children and the great number of mentally retarded children comparatively with other groups of â€Å" inferior individuals† was a reality which the Greek state could not ignore.From the mid of 50’s the 70’s the developments in special education came again from the wide activity of the private sector while the state followed with mainly legislation inferences and the well known sympathy towards the people with special needs. So, during this period educational units were founded and â€Å"deaf and dumb† schools in various areas of Greece and units for motionaly-disabled people. Another offer of the private sector was the foundation of children’s neuropsychiatry clini cs and schools for the group of â€Å"marginal adults† and â€Å" mentally retarded children†.The exemplification of the Greek state and the educational policy of the western countries begins in the mid of the 70’s approximately. Specifically towards the end of the 70’s measures were promoted for the professional rehabilitation of the disabled by giving motives to employers for the employment of these people. Since 1980 and then special classes for the children with, learning difficulties and slight mental retardment began to be estamplished.The Greek state in the 80’s seems to desire to participate actively with the other social factors in an attempt of reorganization of the philosophy and pre-existent structure concerning the people with special needs, which imposed their life and social back round. Precisely, emphasis was given in the whole development and the development of the potential of the people with special needs, their introduction in t he productive procedure and their mutual acceptance in the social group.Today, thousands of individuals with disabilities are introduced to sports in various settings such as schools or in sports clubs in both segregated and integrated settings by a variety of national and international organizations. The momentum for such change is contributed to several reasons: †¢ One of the most important reason is the introduction and approval of a new law, which mandates not only free public education for all children, but most important integration of children with disabilities in schools settings.This law is consideredas a springboard for the recognition for all children’s rights to participate in physical education activities. †¢ A second reason, is beginning of 90’s the implementation of the program â€Å"Sports for All†, which is organized by the General Secretariat of Sports and implemented with the support of different municipalities within Greece. †¢ A third reason, is the mandatory exposure of all students of physical education in adapted physical activity course work during their core university studies.In this way they have the opportunity not only to be introduced, but also to become specialized later on this subject. This has considerably affected their attitude to teach integrated sports. †¢ A fourth reason is the organization of the Paralympic Games of 2004, which is considered one of the largest events in the world. Due to the magnitude of this event, Greece started to evaluate the current status of the movement for sports for the disabled people, as well as, begin to take important actions towards the best organization of the games.

Change Detection Techniques of Remote Sensing Imageries

Change Detection Techniques of Remote Sensing Imageries 1.1 Introduction Over the past years, academics have suggested enormous numbers of change detection techniques of remote sensing imageries and classified them from a different point of views [ 28 ]. These techniques depend on the assumption of spatial independence among pixels. This assumption is valid only for low, medium and high-resolution images but insufficient for VHR images [ 1 ]. This chapter presents the concept, implementation, and assessment of seven change detection techniques using low, medium and high-resolution ORSI. The rest of this chapter is organized into eight sections. Section 3.2 presents a brief description of the study areas. Section 3.3 describes the dataset characteristics of the study areas (Sharm El-Sheikh city and Mahalla al-kubra city – Egypt). Section 3.4 presents the pre-processing performed on the image dataset before change detection process. Section 3.5 provides the accuracy assessment measures used for evaluation of the change detectio n process. Section 3.6 illustrates the concepts of the selected seven change detection techniques . These techniques are post-classification, direct multi-date classification (DMDC), image differencing (ID), image rationing (IR), image symmetric relative difference (ISRD), change vector analysis (CVA), and principal component differencing (PCD). Section 3.7 presents the experimental work. It explains the Implementation and accuracy assessment of applying the selected change detection techniques on an image dataset of Sharm El-Sheikh city- Egypt. Section 3.8 presents the application of â€Å"post-classification† change detection technique on an image dataset of El-Mahalla El-kubra City-Egypt to detect the urban expansion over the agricultural area through the period from 2010 to 2015. Finally, section 3.9 gives the chapter summary. 1.2 The study areas In this chapter, two study areas are selected for the application of the selected change detection techniques. The first area is a part of Sharm el-Sheikh city. It is located on the southern landfill of the Sinai Peninsula, in the South Sinai Governorate, Egypt, on the coastal bar along the Red Sea as shown in figure (3.1). Its population is approximately 73,000 as of 2015 [ 62 ]. Sharm El Sheikh is the administrative hub of Egypt’s South Sinai Governorate, which includes the smaller coastal towns of Dahab and Nuweiba as well as the mountainous interior, St. Catherine and Mount Sinai. Today the city is a holiday resort and significant center for tourism in Egypt. The selected area is about 12.5 Km 2 . The second study area is a village belongs to El Mahalla El Kubra city. El Mahalla El Kubra is a large industrial and agricultural city in Egypt, located in the middle of the Nile Delta on the western bank of the Damietta Branch tributary, as shown in figure (3.2). The city is known for its textile industry. It is the largest city of the Gharbia Governorate and the second largest in the Nile Delta [ 63 ]. The selected area is about 38 Km 2 . 1.3 Images datasets of the study areas In this chapter, two datasets are used. The first dataset consists of two images of Sham el-Sheikh city acquired by Landsat 7 at 2000 and 2010 respectively as shown in figure (3.3). Area of the image lies between Lat. 28 0 37.0091 N, Lon. 34 17 56.3381 E and Lat.   27 57 20.8804 N, Lon. 34 24 43.6080 E. Table (3.1) summarizes the characteristic of these images. Table (3.1 )   Characteristic of Sham el-Sheikh dataset No Spatial resolution Radiometric resolution Number of bands Acquisition date Size [pixels] Area [km 2 ] Width Height 1 30 m 8 bits 3 2000 382 364 12.5143 2 30 m 8 bits 3 2010 382 364 12.5143 (a) (b) Fig (3.3 ) Dataset of Sharm el-Sheikh city- Egypt acquired by Landsat 7 at (a) image acquired at 2000 and the (b) image acquired at 2010. Figure (3.4) illustrates the second dataset of a village belongs to EL Mahalla al-Kubra city in Egypt. It consists of two images acquired in 2010 and 2015. It is taken by El-Shayal Smart web online Software that could acquire Satellite images from Google Earth. The image area lies between Lat. 30 57 46.9032 N, Lon. 31 14 35.4776E and Lat. 30 54 47.00 N, Lon. 31 18 19.98. Table (3.2) summarizes the characteristic of this dataset. (a) (b) Fig ( 3.4 ) Dataset of EL mahalla al-kubra city- Egypt ( Google Earth) (a) image acquired at 2010 and (b) image acquired at 2015. Table (3.2 )   Characteristic of EL mahalla al-kubra dataset No Spatial resolution Radiometric resolution Number of bands Acquisition date Size [pixels] Area [km 2 ] Width Height 1 6 m 8 bits 3 2010 1056 1007 38.2821 2 6 m 8 bits 3 2015 1056 1007 38.2821 1.4 Image Pre-processing for Change Detection Before change detection process, it is usually necessary to carry out the radiometric correction and image registration for the dataset used [ 64 ].   In sections 3.4.1and 3.4.2, the concept of radiometric and image registration are described. The execution of preprocessing on the dataset used is given in section 3.7.2. 1.4.1 Radiometric correction Radiometric conditions are influenced by many factors such as different imaging seasons or dates, different solar altitudes, different view angles, different meteorologic conditions and different cover areas of cloud, rain or snow etc. It may affect the accuracy of most change detection techniques. Radiometric correction is performed to remove or reduce the inconsistency between the values surveyed by sensors and the spe ctral reflectivity and spectral radiation brightness of the objects, which encompasses absolute radiometric correction and relative radiometric correction [ 26 ]. Absolute radiometric correction It mainly rectifies the radiation distortion that is irrelevant to the radiation features of the object surface and is caused by the state of sensors, solar illumination, and dispersion and absorption of atmospheric etc. The typical methods mainly consist of adjusting the radiation value to the standard value with the transmission code of atmospheric radiation, adjusting the radiation value to the standard value with spectral curves in the lab, adjusting the radiation value to the standard value with dark object and transmission code of radiation, rectifying the scene by removing the dark objects and so on. Due to the fact that it is expensive and impractical to survey the atmospheric parameter and ground objects of the current data, and almost impossible to survey that of the histor ical data, it is difficult to implement absolute radiometric correction in most situations in reality. Relative radiometric correction In a relative radiometric correction, an image is regarded as a reference image. Then adjust the radiation features of another image to make it match with the former one. Main methods consist of correction by histogram regularization and correction with fixed object. This kind of correction can remove or reduce the effects of atmosphere, sensor, and other noises. In addition, it has a simple algorithm. So it has been widely used. The radiation algorithms that are most frequently used at present in the preprocessing of change detection mainly consists of image regression method, pseudo-invariant features,   dark set and bright set normalization, no-change set radiometric normalization, histogram matching, second simulation of the satellite signal in the solar spectrum and so on. It should be pointed that radiometric correction isn’t n ecessary for all change detection methods. Although some scholars hold that radiometric corrections are necessary for multi-sensor land cover change analysis Leonardo studies at 2006 have shown that if the obtained spectral signal comes from the images to be classified, it is unnecessary to conduct atmospheric correction before the change detection of post-classification comparison. For those change detection algorithms based on feature, object comparison, radiometric correction is often unnecessary [ 64 ]. 1.4.2 Image registration Precise registration to the multi-temporal imageries is essential for numerous change detection techniques. The importance of precise spatial registration of multi-temporal imagery is understandable because generally spurious results of change detection will be formed if there is misregistration. If great registration accuracy isn’t available, a great deal of false change area in the scene will be caused by image displacement. It is commonly approved that the geometrical registration accuracy of the sub-pixel level is recognized. It can be seen that the geometrical registration accuracy of the sub-pixel level is necessary to change detection. However, it is doubtful whether this result is suitable for all registration data sources and all detected objects and if suitable how much it is. Another problem is whether this result has no influence on all change detection techniques and applications and if there is any influence how much it is. These Problems are worth to be studied further. On the other hand, it is difficult to implement high accuracy registration between multi-temporal especially multi-sensor remote sensing images due to many factors, such as imaging models, imaging angles and conditions, curvature and rotation of the earth and so on. Especially in the mountainous region and urban area, general image registration methods are ineffective and orthorectification is needed. Although geometrical registration of h igh accuracy is necessary to techniques used for low, medium and high resolution (like image differencing techniques and post-classification), it is unnecessary for all change detection t. For the feature-based change detection methods like object-based change detection method, the so-called buffer detection procedure can be employed to associate the extracted objects or features and in this manner, the harsh prerequisite of perfect registration can be escaped [ 65 ]. However, these methods neglect the key problem of the distinction between radiometric and semantic changes. So, it does not address the problem of change detection from a general perspective. It just focuses on specific applications relevant to the end user [ 1 ]. 1.5 Accuracy Assessment used for Change Detection Process evaluation The accuracy of change detection depends on many factors, including precise geometric registration and calibration or normalization, availability and quality of ground reference data, t he complexity of landscape and environment, methods or algorithms used, the analyst’s skills and experience, and time and cost restrictions.   Authors in [ 66 ] summarized the main errors in change detection including errors in data (e.g. image resolution, accuracy of location and image quality), errors caused by pre-processing (the accuracy of geometric correction and radiometric correction), errors caused by change detection methods and processes (e.g. classification and data extraction error), errors in field survey (e.g. accuracy of ground reference) and errors caused by post-processing. Accuracy assessment techniques in change detection originate from those of remote sensing images classification. It is natural to extend the accuracy assessment techniques for processing single time image to that of bi-temporal or multi-temporal images. Among various assessment techniques, the most efficient and widely-used is the error matrix [ 26 ]. It describes the comparison or cr oss-tabulation of the classified land cover to the actual land cover revealed by the sample sites results in an error matrix as demonstrated in the table (3.3). It can be called a confusion matrix, contingency table [ 67 ], evaluation matrix [ 68 ] or misclassification matrix [ 69 ]. Different measures and statistics can be derived from the values in an error matrix. These measures are used to evaluate the change detection process. These measures are overall accuracy, procedures accuracy and user accuracy [ 70 ]. Overall accuracy of the change map It presents the ratio of the total number of correctly classified pixels to the total number of pixels in the matrix. This figure is normally expressed as a percentage. It can be expressed as follows: The overall accuracy =   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (3.1) User’s accuracy (column accuracy) It is a measure of the reliability of change map generated fro m a CD process. It is a statistic that can tell the user of the map what percentage of a class corresponds to the ground-truthed class. It is calculated by dividing the number of correct pixels for a class by the total pixels assigned to that class. The user accuracy =   Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (3.2) Producer’s accuracy (raw accuracy) It is a measure of the accuracy of a particular classification scheme. It shows what percentage of a particular ground class was correctly classified. It is calculated by dividing the number of correct pixels for a class by the actual number of ground truth pixels for that class. The procedure accuracy =   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (3.3) Table ( 3 . 3 ) Change error matrix or confusion matrix. Classified land cover Actual land cover Class1 = change Class2 = no change Class1 = change Correct False Class2 = no change False Correct 1.6 Concepts of the selected change detection techniques Seven LULC change detection techniques are selected to be implemented on our dataset. These techniques are post-classification, direct multi-date classification ( DMDC ), image differencing (ID), image rationing (IR), image symmetric relative difference (ISRD), change vector analysis (CVA), and principal component differencing (PCD). Image differencing Itis based on the subtraction of two spatially registered imageries, pixel by pixel, as follows: ID =X i (t 2 ) – X i (t 1 )  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   (3.4) Where: X represents the multispectral images with I (number of bands) acquired at two different times t 1 and t 2 . The pixel s of changed area are predictable to be scattered in the two ends of the histogram of the resulting image (change map), and the no changed area is grouped around zero as shown in figure (3.5). This simple manner easily infers the resulting image; conversely, it is vital to properly describe the thresholds to perceive the change from non-change regions [ 71 ] . Image Rationing It is similar to image differencing method. The only difference between them is the replacement of the differencing images by rationed images [ 71 ].

An analysis of the policies introduced by the Office of the Mayor of Essay

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California Gold Rush Essay Example | Topics and Well Written Essays - 2500 words

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Commercial Success Storyboard Assignment Example | Topics and Well Written Essays - 500 words

Commercial Success Storyboard - Assignment Example The target audience for the product is smokers between the ages of 18-42. A commercial campaign for this product should be run in the primetime hours of 8:00 P.M. – 11:00 P.M. The commercial should be aired at a time when there is maximum audience in order to reach more people. The firm should select a program that is popular and that is watched by a broad audience. A good show for the company to purchase commercial time on is America’s Got Talent broadcasted by NBC. America’s Got Talent is in the entertainment competition category. The show is aired Tuesdays at 8:00 P.M. eastern. This show is a good candidate because people of all ages and backgrounds watch this show. The creative approach that will be used to attract customers is by emphasizing on three elements: coolness factor, sex appeal, and convenience of the product. A celebrity guest will be included in the commercial. The 30 second commercial that will be prepared for The Electronic Cigarette Company wi ll be delivered using the broadcasting services of NBC. NBC is considered one of the market leaders among national television stations. Despite being one of the market leaders NBC has very reasonable pricing in comparison with the competition.

Chinese Culture Term Paper Example | Topics and Well Written Essays - 2750 words

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America now and before Essay Example | Topics and Well Written Essays - 750 words

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The Octagon House Essay Example | Topics and Well Written Essays - 250 words

The Octagon House - Essay Example The building is made of bricks, sandstone, and cold stone. The six-sided building has a symmetrical wing that fits well with its triangular lot (Lonely Planet, 2014).   The building closely resembles the octagonal and circular buildings that prominently featured in England during the 1700s and the 1800s (Fodors, 2014). The building is a notable example of U.S. federal architecture. The building has chimneys and a furnace for heating water sits in the basement. It also has a central spiral staircase and the rooms are so arranged that they appear to be symmetrical while its roof is flat and surmounted by a cupola. The roof of the building is made of cedar and shingle and has a balustrade. Some of the rooms that are in the building are the treaty room, dining room, parlor, and kitchen. Today, the building is under use as a museum and hosts exhibits related to building design and architecture. Generally, the building is simple in design. It was designed differently from the traditional buildings that were common in Washington DC at the time of its construction. The traditional style at the time of its construction was Georgian. It is partly inspired by the  Federal style architecture, creativity, and Greek interior style (AIA, 2014).

Mathematics of Finance Essay Example | Topics and Well Written Essays - 1250 words

Mathematics of Finance - Essay Example The potential of real option analysis is like Discounted Cash Flows (DCF), and other investment analysis techniques is simply another tool. The two techniques are complementary. Management should employ both methods in the analysis of potential investments and gather information from both (Amram, 2000). Further, we must consider a real option analysis is not ordinarily a simple technique. With it comes an amount of technical comfort required on the part of the analyst in order to implement the technique correctly. Like most techniques derived from financial theory, it is easily abused. Those who will utilize the information provided by real option analysis need training in the proper interpretation of its results (Eiteman, 2007). DCF analysis, defined as the process of valuing capital budgeting projects by discounting their future expected cash flows. DCF framework, defined as the valuing of an asset by discounting its expected future cash flows at some discount rate. Real option analysis is gaining in use and popularity. Senior management prefers this option because it has two sequences of a project. It describes the cash inflows and out flows at different times. Usually this is the way that management sees projects unfold. Real option analysis values management by its very nature.

Zaras Business Model Essay Example for Free

Zaras Business Model Essay When I saw the first announcement of their ecommerce launch I ran home and dug through my undergrad course work and quickly produced a case study I’d read in 2003. â€Å"Zara: IT for Fast Fashion† a Harvard Business School case study that examined Zara’s IT infrastructure and how it supported their unique business model. Two important caveats from this case study stuck out in my mind. Zara’s business model closely linked customer demand to manufacturing and distribution. Inventory depended largely on the location of the store and what particular customers were buying. They understood that their consumer had a penchant for trend driven pieces, and that marketing and advertising efforts lengthened the lead-time. Thus their marketing budget was usually .3% of revenue, and Zara was able to get high fashion looks in stores while they were still hot. Zara didn’t need to convince their consumers to buy with advertising and marketing efforts, rather they changed 75% of their inventory every three to four weeks, so consumers knew to constantly frequent the store for up to date items. Secondly, Zara had decided not to retail clothes online because of the high rate of returns (retail mail order rates were 50-60% whereas in store was roughly 5%), and because their distribution centers were not configured for small pick and pack orders. If you think about it, Zara’s business model is actually perfect for online retail. Their vertically integrated manufacturing operations allowed for the perpetual introduction of new pieces with short lead times. For the fickle online consumer that wants newness all the time, its heaven! In fact, the top right hand corner of their site pays homage to this brand ethos with a â€Å"new this week† link standing out from the pack. So what took them so long to make the move?

The main cause of the Wall Street Essay Example for Free

The main cause of the Wall Street Essay I do not agree wholly with that statement. The panic selling of shares was the immediate cause to the Wall Street crash. However, if there had not have been the panic selling of shares then there would not have been such a dramatic slump but a smaller one. America was doing well in the end of the 1920s; the boom had made half the population happy. However, now that all the people who could afford it had brought electrical goods, cars etc there was no one else left to buy the surplus products. This is called overproduction, this means that there are too many products and the market is saturated, this usually starts off a slump. The companies were then starting to do not as well, this meant a fall in the share prices. The people in the know at the time had sold their shares and then all the other people who had invested in them panicked to sell their own shares causing the Wall Street crash. In the 1920s the wealth had not been evenly split, blacks, immigrants and farmers were not doing as well, this meant that half the population could not afford to buy the new products being mass-produced causing overproduction to happen quicker, if the wealth had been evenly spread then I do still think that there would have been a crash, however, it would have been a few years later. To increase the boom in the 1920s America put taxes on products coming in from abroad to make it a stronger economic country. The countries in Europe then retaliated and put a tax on all American goods. This meant that there were a lot of extra products not being sold; this was a part of overproduction. In the stock market a lot of speculators were playing with borrowed money from the bank because they felt that they were confident enough to win it back. Speculators were people who knew nothing about stocks but saw that a company was making profit in shares so they would invest in them if they were confident enough. This meant that companys products were worth a lot more in stock than they were in real life. This meant that at the time of the crash there was a hell of a long way to go down causing many people to go bankrupt. Because of overproduction many experts in the know decided to sell their shares, other people who owned shares in the same company then started to panic and quickly tried to sell there shares causing the prices of the company to plummet. The panic selling of shares technically was the Wall Street crash. I do not think that the panic selling of shares was the main cause for the Wall Street crash; I think that it was overproduction. Overproduction was always going to happen, it could have been postponed a few years if the wealth in America had been spread evenly or if Europe hadnt put a tax on all American goods. Even if this had been the case overproduction would have happened sooner or later. Overproduction caused some people to sell their shares that then lead to everyone panicking to sell their shares causing the Wall Street crash. If speculators had not have put in so much money there would not have been such a big slump but there would have been one. The panic selling of the shares was the last thing to happen and probably the most influential thing to happen before the crash. However, the thing that started the crash off was overproduction.

An operational amplifier

An operational amplifier Introduction: Anoperational amplifier, which is often called anop-amp, is aDC-coupledhigh-gainelectronic voltageamplifierwith a differential input and, usually, a single-ended output.An op-amp produces an output voltage that is typically millions of times larger than the voltagedifferencebetween its input terminals. Typically uses of the operational amplifier are to provide voltage amplitude changes (amplitude and polarity), oscillators, filter circuits, and many types of instrumentation circuits. An op-amp contains a number of differential amplifier stages to achieve a very high voltage gain. Typically the op-amps very large gain is controlled bynegative feedback, which largely determines the magnitude of its output voltage gain in amplifier applications, or thetransfer functionrequired. Without negative feedback, and possibly withpositive feedbackforregeneration, an op-amp essentially acts as acomparator. High inputimpedanceat the input terminals and low output impedance at the output terminals (ideally zero) are important typical characteristics. Op-amps are among the most widely used electronic devices today, being used in a vast array of consumer, industrial, and scientific devices. Many standard IC op-amps cost only a few cents in moderate production volume; however some integrated or hybrid operational amplifiers with special performance specifications may cost over $100 US in small quantities. Op-amps sometimes come in the form of macroscopic components, or asintegrated circuitcells; patterns that can be reprinted several times on one chip as part of a more complex device. The op-amp is one type ofdifferential amplifier. Other types of differential amplifier include thefully differential amplifier(similar to the op-amp, but with two outputs), theinstrumentation amplifier(usually built from three op-amps), theisolation amplifier(similar to the instrumentation amplifier, but with tolerance to common-mode voltages that would destroy an ordinary op-amp), andnegative feedback amplifier(usually built from one or more op-amps and a resistive feedback network). An Amplifier is made of: A Gain Block (ideally possessing infinite gain) Feedback A Network that sets the amount of feedback (e.g. resistors) The circuit symbol for an op-amp is shown to the right, where: The power supply pins (V_{text{S}!+}andV_{text{S}!-}) can be labelled in different ways). Despite different labelling, the function remains the same to provide additional power for amplification of signal. Often these pins are left out of the diagram for clarity, and the power configuration is described or assumed from the circuit. Op amps are versatile ICs that can perform a variety of mathematical functions. For this reason, they are the building blocks of many signal processing circuits. They have almost infinite gain, high input impedance, and low output impedance. Because of this, there is no current drawn at either input, and the voltage at both inputs must be equal (they are often drawn with a short connecting them) Op amps have two inputs, an inverting (-) and non inverting (+). A positive voltage source and negative voltage source or ground are connected directly to the op amp, although these are rarely shown on circuit diagrams. There is a single output, which is almost always connected to the inverting input with a feedback loop. Ideal Op Amps: There are three rules for analyzing op amp circuits. In addition to KVL and KCL, any op amp circuit should be solvable with these rules. Infinite input impedance. No current is drawn so: Infinite gain. This means that the input voltages must be equal. Zero output impedance. This means that output voltage does not depend on the output current. Real Op Amps: Ideal op amps are modelled with infinite gain and infinite impedance. While real op amps have high gain and low impedance, they are not infinite. This limiting factor can affect the performance of the circuit, so it should be considered. Another limitation of real op amps is voltage gain. Instead of being infinite, the maximum output voltage is about 1.4 V lower than the supply voltage (this is due to diode drops in the op amp). Ideal behaviour is not an accurate modelling technique when square waves are used. For this type of input, the voltage changes infinitely fast as it jumps from the high to the low parts of the wave. Op amps cant change instantaneously, there is a slight slope produced in the output. This can be measured by the slew rate (with is the change in voltage over the change in time). Rise time is another parameter used to calculate how quickly an op amp can adjust. The amount of time it takes the voltage to change from 10% to 90% of the desired value is the rise time. For application with square wave input, these two factors can affect the response of your circuit. Connecting an Op Amp: Op amps with Dual in Line Packages should be connected to a breadboard as shown here. The notch is at the top of the op-amp, with pins counted counter clockwise from the upper left corner. Operation: The amplifiers differential inputs consist of V_{!+}input and aV_{!-}input, and ideally the op-amp amplifies only the difference in voltage between the two, which is called thedifferential input voltage. The output voltage of the op-amp is given by the equation, WhereV_{!+}the voltage at the non-inverting terminal is,V_{!-}is the voltage at the inverting terminal andGopen-loopis theopen-loopgain of the amplifier. (The term open-loop refers to the absence of a feedback loop from the output to the input.) Op-amp with inverting input grounded through a resistor; input at the non-inverting input, and no feedback With no negative feedback, the op-amp acts as a switch. The inverting input is held at ground (0 V) by the resistor, so if the Vinapplied to the non-inverting input is positive, the output will be maximum positive, and if Vinis negative, the output will be maximum negative. Since there is no feedback from the output to either input, this is anopen loopcircuit. The circuits gain is just the Gopen-loopof the op-amp. Standard two-resistor non-inverting amplifier circuit The magnitude ofGopen-loopis typically very large-seldom less than a million-and therefore even a quite small difference betweenV_{!+}andV_{!-}(a few microvolts or less) will result in amplifier saturation, where the output voltage goes to either the extreme maximum or minimum end of its range, which is set approximately by the power supply voltages.Finleys lawstates that When the inverting and non-inverting inputs of an op-amp are not equal, its output is in saturation. Additionally, the precise magnitude ofGopen-loopis not well controlled by the manufacturing process, and so it is impractical to use an operational amplifier as a stand-alonedifferential amplifier. If linear operation is desired,negative feedbackmust be used, usually achieved by applying a portion of the output voltage to the inverting input. The feedback enables the output of the amplifier to keep the inputs at or near the same voltage so that saturation does not occur. Another benefit is that if much negative feedb ack is used, the circuits overall gain and other parameters become determined more by the feedback network than by the op-amp itself. If the feedback network is made of components with relatively constant, predictable, values such as resistors, capacitors and inductors, the unpredictability and inconstancy of the op-amps parameters (typical of semiconductor devices) do not seriously affect the circuits performance. If no negative feedback is used, the op-amp functions as a switch or comparator. Positive feedback may be used to introducehysteresisor oscillation. Returning to a consideration of linear (negative feedback) operation, the high open-loop gain and low input leakage current of the op-amp imply two golden rules that are highly useful in analysing linear op-amp circuits. Golden rules of op-amp negative feedback Ifthere is negative feedback andifthe output is not saturated, both inputs are at the same voltage; no current flows in or out of either input. These rules are true of the ideal op-amp and for practical purposes are true of real op-amps unless very high-speed or high-precision performance is being contemplated (in which case account must be taken of things such as input capacitance, input bias currents and voltages, finite speed, and otherop-amp imperfections, discussed in a later section.) As a consequence of the first rule, theinput impedanceof the two inputs will be nearly infinite. That is, even if the open-loop impedance between the two inputs is low, the closed-loop input impedance will be high because the inputs will be held at nearly the same voltage. This impedance is considered as infinite for an ideal opamp and is about onemegaohmin practice. Ideal and real op-amps: An equivalent circuit of an operational amplifier that models some resistive non-ideal parameters. An ideal op-amp is usually considered to have the following properties, and they are considered to hold for all input voltages: Infiniteopen-loop gain(when doing theoretical analysis, alimitmay be taken as open loop gainGgoes to infinity) Infinite voltage range available at the output (vout) (in practice the voltages available from the output are limited by the supply voltagesV_{text{S}!+}andV_{text{S}!-}) Infinitebandwidth(i.e., the frequency magnitude response is considered to be flat everywhere with zerophase shift). Infiniteinput impedance(so, in the diagram,R_{text{in}} = infty, and zero current flows fromv_{!+}tov_{!-}) Zero input current (i.e., there is assumed to be noleakageorbiascurrent into the device) Zeroinput offset voltage(i.e., when the input terminals are shorted so thatv_{!+}=v_{!-}, the output is avirtual groundor vout= 0). Infiniteslew rate(i.e., the rate of change of the output voltage is unbounded) and power bandwidth (full output voltage and current available at all frequencies). Zerooutput impedance(i.e.,Rout= 0, so that output voltage does not vary with output current) Zeronoise InfiniteCommon-mode rejection ratio(CMRR) InfinitePower supply rejection ratiofor both power supply rails. In practice, none of these ideals can be realized, and various shortcomings and compromises have to be accepted. Depending on the parameters of interest, a real op-amp may be modelled to take account of some of the non-infinite or non-zero parameters using equivalent resistors and capacitors in the op-amp model. The designer can then include the effects of these undesirable, but real, effects into the overall performance of the final circuit. Some parameters may turn out to havenegligibleeffect on the final design while others represent actual limitations of the final performance that must be evaluated. History: 1941: First (vacuum tube) op-amp An op-amp, defined as a general-purpose, DC-coupled, high gain, inverting feedbackamplifier, is first found in US Patent 2,401,779 Summing Amplifier filed by Karl D. Swartzel Jr. of Bell labs in 1941. This design used threevacuum tubesto achieve a gain of 90dB and operated on voltage rails of  ±350V. It had a single inverting input rather than differential inverting and non-inverting inputs, as are common in todays op-amps. ThroughoutWorld War II, Swartzels design proved its value by being liberally used in the M9artillery directordesigned at Bell Labs. This artillery director worked with the SCR584radarsystem to achieve extraordinary hit rates (near 90%) that would not have been possible otherwise. 1947: First op-amp with an explicit non-inverting input In 1947, the operational amplifier was first formally defined and named in a paper by Professor John R. Ragazzini of Columbia University. In this same paper a footnote mentioned an op-amp design by a student that would turn out to be quite significant. This op-amp, designed by Loebe Julie, was superior in a variety of ways. It had two major innovations. Its input stage used a long-tailedtriode pair with loads matched to reducedriftin the output and, far more importantly, it was the first op-amp design to have two inputs (one inverting, the other non-inverting). The differential input made a whole range of new functionality possible, but it would not be used for a long time due to the rise of the chopper-stabilized amplifier. 1949: First chopper-stabilized op-amp In 1949, Edwin A. Goldberg designed achopper-stabilized op-amp.This set-up uses a normal op-amp with an additionalACamplifier that goes alongside the op-amp. The chopper gets an AC signal fromDCby switching between the DC voltage and ground at a fast rate (60Hz or 400Hz). This signal is then amplified, rectified, filtered and fed into the op-amps non-inverting input. This vastly improved the gain of the op-amp while significantly reducing the output drift and DC offset. Unfortunately, any design that used a chopper couldnt use their non-inverting input for any other purpose. Nevertheless, the much improved characteristics of the chopper-stabilized op-amp made it the dominant way to use op-amps. Techniques that used the non-inverting input regularly would not be very popular until the 1960s when op-ampICsstarted to show up in the field. In 1953, vacuum tube op-amps became commercially available with the release of the model K2-W from George A. Philbrick Researches, Incorporated. The designation on the devices shown, GAP/R, is a contraction for the complete company name. Two nine-pin 12AX7 vacuum tubes were mounted in an octal package and had a model K2-P chopper add-on available that would effectively use up the non-inverting input. This op-amp was based on a descendant of Loebe Julies 1947 design and, along with its successors, would start the widespread use of op-amps in industry. 1961: First discrete IC op-amps With the birth of thetransistorin 1947, and the silicon transistor in 1954, the concept of ICs became a reality. The introduction of theplanar processin 1959 made transistors and ICs stable enough to be commercially useful. By 1961, solid-state, discrete op-amps were being produced. These op-amps were effectively small circuit boards with packages such as edge-connectors. They usually had hand-selected resistors in order to improve things such as voltage offset and drift. The P45 (1961) had a gain of 94dB and ran on  ±15V rails. It was intended to deal with signals in the range of  ±10V. 1962: First op-amps in potted modules By 1962, several companies were producing modular potted packages that could be plugged intoprinted circuit boards. These packages were crucially important as they made the operational amplifier into a singleblack boxwhich could be easily treated as a component in a larger circuit. 1963: First monolithic IC op-amp In 1963, the first monolithic IC op-amp, the  µA702 designed byBob Widlarat Fairchild Semiconductor, was released. MonolithicICsconsist of a single chip as opposed to a chip and discrete parts (a discrete IC) or multiple chips bonded and connected on a circuit board (a hybrid IC). Almost all modern op-amps are monolithic ICs; however, this first IC did not meet with much success. Issues such as an uneven supply voltage, low gain and a small dynamic range held off the dominance of monolithic op-amps until 1965 when the  µA709 was released. 1966: First varactor bridge op-amps Since the 741, there have been many different directions taken in op-amp design.Varactorbridge op-amps started to be produced in the late 1960s; they were designed to have extremely small input current and are still amongst the best op-amps available in terms of common-mode rejection with the ability to correctly deal with hundreds of volts at their inputs. 1968: Release of the  µA741 The popularity of monolithic op-amps was further improved upon the release of the LM101 in 1967, which solved a variety of issues, and the subsequent release of the  µA741 in 1968. The  µA741 was extremely similar to the LM101 except that Fairchilds facilities allowed them to include a 30pF compensation capacitor inside the chip instead of requiring external compensation. This simple difference has made the 741thecanonical op-amp and many modern amps base their pin out on the 741s.The  µA741 is still in production, and has become ubiquitous in electronics-many manufacturers produce a version of this classic chip, recognizable by part numbers containing741. 1970: First high-speed, low-input current FET design In the 1970s high speed, low-input current designs started to be made by usingFETs. These would be largely replaced by op-amps made withMOSFETsin the 1980s. During the 1970s single sided supply op-amps also became available. 1972: Single sided supply op-amps being produced A single sided supply op-amp is one where the input and output voltages can be as low as the negative power supply voltage instead of needing to be at least two volts above it. The result is that it can operate in many applications with the negative supply pin on the op-amp being connected to the signal ground, thus eliminating the need for a separate negative power supply. The LM324 (released in 1972) was one such op-amp that came in a quad package (four separate op-amps in one package) and became an industry standard. In addition to packaging multiple op-amps in a single package, the 1970s also saw the birth of op-amps in hybrid packages. These op-amps were generally improved versions of existing monolithic op-amps. As the properties of monolithic op-amps improved, the more complex hybrid ICs were quickly relegated to systems that are required to have extremely long service lives or other specialty systems. Recent trends Recently supply voltages in analog circuits have decreased (as they have in digital logic) and low-voltage op-amps have been introduced reflecting this. Supplies of  ±5V and increasingly 5V are common. To maximize the signal range modern op-amps commonly have rail-to-rail inputs (the input signals can range from the lowest supply voltage to the highest) and sometimes rail-to-rail outputs. A very typical commercial IC op amp circuit is the 741. This IC has been available for many years, and a number of variations have been developed to help minimize the errors inherent in its construction and operation. Nevertheless, the analysis we will perform here using the 741 will apply to any other IC op amp, if you take into account the actual parameters of the device you are actually using. Therefore, we will use the 741 as our example IC op amp. A differential amplifier connected as an op amp. To the right is a circuit using the 741 op amp IC, with the input and feedback resistors that are required for this circuit to operate properly in an analog computer. Note that there are actually two inputs to the amplifier, designated + and - in the figure. This is because the 741, like all IC op amps of this type, is in fact a differential amplifier. Thus, the output voltage is determined by thedifferencebetween the two input voltages. The +, or non-inverting input, is grounded through a resistor as shown. Thus, its input voltage is always zero. The -, or inverting input, is the one that is actively used. Thus, we establish that the inverting input, which is also the junction of the input and feedback resistors, must operate as a virtual ground in order to keep the output voltage within bounds. So far, so good, but what about the actual voltage gain? It cant possibly be infinite, and if it isnt infinite, there must be some non-zero input voltage to produce a non-zero output voltage. In fact, the typical open-loop voltage gain for the 741 is 200,000. This does not mean that every such device has a gain of 200,000, however. What is guaranteed is that the commercial version (the 741C) will have a minimum gain of 20,000. The military version is more stringently selected, and will have a minimum voltage gain of 50,000. For the 741C, then, with a maximum output voltage of  ±10 volts, the maximum input voltage required at the inverting input can never be more than  ±10/20,000 =  ±0.0005 volt, or 0.5 milli volts. Typical measurement accuracy uses three significant digits, so we would measure voltages from 0.00 volts to  ±10.00 volts. The maximum input voltage is more than an order of magnitude smaller than this, and hence is insignificant in a typical analog computer. But what about input bias current? Surely the IC requires at leastsomesmall amount of input current? Well, yes, it does. The 741C requires a typical input bias current of 80 nA (thats nano Amperes, where 1nA=10-9A). The maximum input bias current for the 741C is 500nA, or 0.5 µA. So how do we use this information to minimize the errors it could cause into insignificance? Well, lets consider the resistance that would be required for this current to cause a significant voltage drop. If we keep the voltage error small enough, we can ignore it as immeasurable. This means we must keep the values of Rinand Rfas small as possible, consistent with proper operation of the circuit. At the same time, we cannot make them too small, or the op amp itself will be overloaded. For proper operation, the total load resistance at the 741 output should not be smaller than 2000 ohms, or 2k. This amounts to a maximum output current of 5 mA at 10 volts output. This means that the output resistance of the op amp is not the desired zero ohms. However, as long as you dont draw too much current from the output, the use of heavy negative feedback has an added benefit: It makes the op amp behaveas ifit had zero output resistance. That is, any internal resistance will simply mean that the op amp must produce an internal voltage enough higher than the calculated value so that the final output voltage will be the calculated value. So what if we make our input and feedback resistors about 10k each? Then the current demand on the output is only 1 mA at 10 volts, leaving plenty of capacity for additional inputs. And the voltage caused by the input bias current wont exceed 10,000-0.5-10-6=0.005volt. This is half of the least significant digit of our measurement capability, which is not as good as we would like, but will do. Also, this is the absolute worst-case situation; most practical applications wont see an error this big. In addition, the input bias current applies equally to both inputs. This is the reason for the resistor connecting the + input to ground. If this resistor is close in value to the parallel combination of Rin and Rf, the same voltage error will be generated at the two inputs, and will therefore be cancelled out, or very nearly. Thus, we can relegate this problem to true insignificance by means of correct circuit design and careful choice of component values. The 741 does also have two error characteristics, calledinput offset voltageandinput offset current, which define the inherent errors which may exist between the two inputs to the IC. However, the 741 also has the means for balancing these variations out, so the actual errors are minimized or eliminated, thus once again removing them from significance. A problem with any op amp is a limited frequency response. The higher the gain of the complete circuit, the lower the working frequency response. This is one reason an overall gain of 20 is a practical limit. (Another reason is that the input and feedback resistors become too different from each other.) Also, the standard 741 has aslew rateof 0.5v/ µs. This means that the output voltage cannot change any faster than this. The newer generation of op amps, such as the 741S, have a slew rate more like 5v/ µs, and hence can operate over the entire audio range of frequencies without serious problems. Classification of Operational Amplifier: Op-amps may be classified by their construction: discrete (built from individualtransistorsortubes/valves) IC (fabricated in anIntegrated circuit) most common hybrid IC op-amps may be classified in many ways, including: Military, Industrial, or Commercial grade (for example: the LM301 is the commercial grade version of the LM101, the LM201 is the industrial version). This may defineoperating temperatureranges and other environmental or quality factors. Classification by package type may also affect environmental hardiness, as well as manufacturing options;DIP, and other through-hole packages are tending to be replaced bySurface-mount devices. Classification by internal compensation: op-amps may suffer from high frequencyinstabilityin somenegative feedbackcircuits unless a small compensation capacitor modifies the phase- and frequency- responses; op-amps with capacitor built in are termedcompensated, or perhaps compensated forclosed-loopgains down to (say) 5, others: uncompensated. Single, dual and quad versions of many commercial op-amp IC are available, meaning 1, 2 or 4 operational amplifiers are included in the same package. Rail-to-rail input (and/or output) op-amps can work with input (and/or output) signals very close to the power supply rails. CMOSop-amps (such as the CA3140E) provide extremely high input resistances, higher thanJFET-input op-amps, which are normally higher thanbipolar-input op-amps. Other varieties of op-amp include programmable op-amps (simply meaning the quiescent current, gain, and bandwidth and so on can be adjusted slightly by an external resistor). Manufacturers often tabulate their op-amps according to purpose, such as low-noise pre-amplifiers, wide bandwidth amplifiers, and so on. Single-Ended Inputs With single-ended inputs you connect one wire from each signal source to the data acquisition interface the Micro link. The measurement is the difference between the signal and the ground or earth at the Micro link. This method relies on the signal source being grounded (earthed), and the signal sources ground and the Micro links ground having the same value. Differences in Ground Levels We think of the ground as a constant 0V, but in reality the ground, or earth, is at a different level in different places. The closer together the places, the more likely the ground level will be the same. Make a connection between two grounds and the difference in levels can drive large currents, known as earth or ground loops. This can lead to errors when using single-ended inputs. Noise Errors Single-ended inputs are sensitive to noise errors. Noise (unwanted signal contamination) is added because signal wires act as aerials, picking up environmental electrical activity. With single-ended inputs you have no way of distinguishing between the signal and the noise. The ground and noise problems can be solved by differential inputs. Differential Inputs With differential inputs, two signal wires run from each signal source to the Microlink. One goes to a + input and one to a input. Two high-impedance amplifiers monitor the voltage between the input and the interface ground. The outputs of the two amplifiers are then subtracted by a third amplifier to give the difference between the + and inputs, meaning that any voltage common to both wires is removed. This can solve both of the problems caused by single-ended connections. It means that differences in grounds are irrelevant (as long as they arent too large for the amplifier to handle). It also reduces noise twisting wires together will ensure that any noise picked up will be the same for each wire. Floating Signals A common problem when using differential inputs is neglecting any connection to ground. For example, battery-powered instruments and thermocouples have no connection to a buildings ground. You could connect a battery, for instance, between the Micro links + and inputs. The 2 input amplifiers will try to monitor the voltages + to earth and to ground. However, as there is no connection between the battery and ground, these voltages to ground could be any value and may be too large for the amplifier to handle. For these floating signal sources you should provide a reference. The Micro link has a socket labelled 0V. Run a wire from, say, the wire to this OV socket, either directly or via a resistor. (If your signal source is itself grounded dont make a connection to the Micro links 0V socket.) Amplifier Ability and Operating Range The three amplifiers used for differential inputs are collectively known as an instrumentation amplifier. Ideally, as previously described, any voltage common to both wires (common mode voltage) is cancelled. In practice the two input amplifiers are not perfectly matched so a fraction of the common mode voltage may appear. How closely the instrumentation amplifier approaches the ideal is expressed as the common mode rejection ratio (CMRR). This is the reciprocal of the fraction let through and is usually given in decibels. The higher the rejection ratio the better. Another specification to look for is the common mode range. This is the maximum contamination voltage with which the amplifier can cope. If the difference in ground levels between your interface and signal source exceeds this value, your measurement will be inaccurate. Less Signals with Differential Inputs? An obvious disadvantage of differential inputs is that you need twice as many wires, so you can connect only half the number of signals, compared to single-ended inputs. Should you decide that single-ended inputs are OK for you if you have short signal wires, close together signal sources, and signals larger than around 100 mV for e.g. you can use differential inputs in single-ended mode. To do this short one of the signal wires (usually the input) to the Micro link V input. Differential inputs, therefore, give you the option of either mode. Op-Amp Characteristics: A very typical commercial IC op amp circuit is the 741. This IC has been available for many years, and a number of variations have been developed to help minimize the errors inherent in its construction and operation. Nevertheless, the analysis we will perform here using the 741 will apply to any other IC op amp, if you take into account the actual parameters of the device you are actually using. Therefore, we will use the 741 as our example IC op amp. A differential amplifier connected as an op amp. To the right is a circuit using the 741 op amp IC, with the input and feedback resistors that are required for this circuit to operate properly in an analog computer. Note that there are actually two inputs to the amplifier, designated + and - in the figure. This is because the 741, like all IC op amps of this type, is in fact a differential amplifier. Thus, the output voltage is determined by thedifferencebetween the two input voltages. The +, or non-inverting input, is grounded through a resistor as shown. Thus, its input voltage is always zero. The -, or inverting input, is the one that is actively used. Thus, we establish that the inverting input, which is also the junction of the input and feedback resistors, must operate as a virtual ground in order t