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案例分析题Set 3The Evolution of the PhotofitSecurity technology: A new type of computerised photofit system takes a novel evolutionary approach to generating images of suspects. If you have ever tried to describe someone’s face in detail, you will understand why the "photofit" composite images used by the police look so dodgy. In recent years, computerised "E-Fit" systems have helped improve the accuracy of these images by allowing witnesses to choose from a wider range of facial features. But researchers at the University of Stirling in Scotland found that, despite these improvements, people still have a hard time constructing recognisable faces--especially if there is a delay of moreThe problem is that people tend to recoguise faces as whole entities, rather than as separate features. So picking from a range of eyes, noses and mouths is not necessarily the most suitable approach, says Charlie Frowd, a psychologist at the University of Stifling. Next year, however, British police are expected to begin trials of a new computerised system, called EvoFIT, developed by Dr. Frowd and his colleague Peter Hancock. It uses an evolutionary approach, known as a genetic algorithm, to "evolve" faces rather than piece them together."The process is entirely non-verbal and takes a fraction of the normal time," claims Dr. Frowd. A witness is shown an array of 60 different faces with random features. Having studied them closely, the witness is asked to choose the six images that most closely resemble the person they are trying to describe. These six are then used to generate another set of 60, by switching featurees between some of the images and by making random changes to others. The witness is then asked to repeat the task, whereupon a new batch of faces is generated, and so on. In evolutionary terms, this process is known as "genetic crossover and mutation", and is a powerful way to search a large number of possibilities for a particular solution. By allowing the user to steer the selection process, the program is able to generate a good likeness for the original face after just a few cycles.In one of its early versions, EvoFIT was used by police in Northampton shire who were trying to catch a violent attacker. The attacker was never caught, but the senior investigating officer, Superintendent Paul Spick, says the witness involved found the new software much quicker and easier to use than traditional E-Fit systems. It was also more accurate: the final image caused the witness visible distress when displayed. A further important advantage of EvoFIT over traditional composites is that an image can be generated even if the witness can only provide a sketchy verbal description.The researchers have since made a number of further improvements to their system and are now in the process of commercializing it in partnership with ABM, a British firm which supplies police forces with photofit, one of the leading computerized composite systems. The images are more realistic, and the system can generate three-quarter angle views of the face, which are easier to distinguish than direct frontal views, says Dr. Frowd.His team has also found that by combining the images generated by different witnesses, or even from a single witness, it is possible to get an even better likeness.This could be particularly useful when multiple witnesses come forward and the police are unsure which of the images they produce is the most accurate.In the latest version, witnesses are given a selection of face shapes to choose from before facial features are added. This makes it less likely that the correct facial features will be rejected simply because they are on the wrong-shaped face.These modifications appear to make all the difference. In recent experiments, Dr. Frowd and Dr. Hancock compared EvoFIT with the computerized systems currently in use by asking volunteers to construct an image of a face two days after seeing it, and then showing the resulting image to people who were familiar with the person depicted. With traditional composites, the person was correctly identified about 4% of the time; the figure rose to 25% with EvoFIT images.Next year ABM will perform inhouse evaluations of the system and will then team up with police forces for further trials. Although things look promising so far, two things in particular need further testing, says Leslie Bowie, ABM’s director of research. Do the EvoFIT images distract witnesses or contaminate their memories of the face they are trying to recall And while EvoFIT has performed well in the calm conditions of the laboratory, how will it cope with real-life witnesses, who are often traumatized by their experiences If it can address these two questions, EvoFIT could be the next step in the evolution of the photofit. The word its in paragraph 4 refers to().
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Set 6 Biology LectureNarratorListen to a lecture in the literature class.{$mediaurl} What is the main topic of the talk()
案例分析题Set 2Gadgets with a Sporting ChanceConsumer electronics: New sports equipment, from tennis rackets to running shoes, uses processing power to enhance performance. Is that fair Why should aspiring athletes stand on the sidelines when a spot of electronic assistance can put them in the middle of the game That is the question many sports-equipment makers are asking as they sense an opportunity to boost their sales with high-tech products. You could call it the revenge of the nerds: a new wave of microchip-equipped sporting goods promises to enhance the performance of novices and non-sporting types alike--and could even make difficult sports easier.Take cross-country skiing. Victor Petrenko, an engineer at Dartmouth College’s Ice Research Lab in New Hampshire, has invented some smart ski-brakes that, he believes, will increase the popularity of cross-country skiing by making the sport less challenging for beginners. The brakes, currently being tested by a ski manufacturer in the Alps, offer the necessary friction for a bigger "kick-off force" and make the skis less likely to slide backwards in their trucks. To make this happen, an electric current from the bottom of the skis pulses through the ice, melting a thin layer of snow that instantly refreezes and acts as a sort of glue.This is not the only form of smart ski to hit the slopes. Atomic, a leading ski-maker based in Austria, plans to introduce a system later this year that runs a diagnostic safety check to ensure that the ski binding is properly closed, with the result being shown on a tiny built-in liquid-crystal display. Meanwhile, tennis equipment manufacturers are hoping that innovation will bring new zip to their business as well. They certainly need to do something: according to Sport ScanInfo, a market-research firm based in Florida, sales of tennis rackets in America fell 12.5% during the first half of 2004 compared with the first half of 2003.With the ball clearly in their court, researchers at Head, a maker of sporting equipment, have devised a product that should appeal to players suffering from tennis elbow. A chip inside the racket controls piezo-electric fibres, which convert mechanical energy from the ball’s impact into electrical potential energy. This energy is then used to generate a counter-force in the piezo-electric fibres that causes a dampening effect. All of this, the firm says, translates into less stress on the elbow. Head claims that residual vibrations in the racket are dampened twice as fast as in conventional rackets, reducing the shock experienced by the player’s arm by more than 50%.No doubt purists will object that this is simply not cricket. Rule-makers in many sports are now being forced to consider the implications of equipment that promises to augment athletes’ performance with electronic muscle. The International Tennis Federation, that body is responsible for setting the rules of the game, has specified in its most recent guidelines that "no energy source that in any way changes or affects the playing characteristics of a racket may be built into or attached to a racket".Yet despite such wording, the guideline does not actually eliminate the use of Head’s smart rackets, because there is no external energy source---the damping effect relies solely on energy from the ball’s impact. Though high-tech equipment may cause controversy on the court, tennis clubs have to adhere to the guidelines set for the sport, explains Stuart Miller, the ITF’s technical manager. And if the rules allow self-generated forces to modify a racket’s response, so be it.Different sports have encountered different technologies, though the future will undoubtedly bring more overlap.In golf, gadgets that pinpoint the location of the green using the Global Positioning System (GPS),The rule-making body of the Royal and Ancient Golf Club of St. Andrews, which oversees the game in all countries except America and its dependencies, currently prohibits the use of distance-measuring devices.As a result, golfers cannot rely on GPS aids in a tournament. While technological innovation in golf equipment should continue, the player’s skill should remain the predominant factor, says David Rickman, who is in charge of the club’s rules and equipment standards.The trend towards high-tech assistance is not limited to sports with a reputation for expensive gear, however. Even runing, that most basic of sports, provides scope for electronic enhancement. The Adidas running shoe, which is due to be launched in December, incorporates a batterypowered sensor that takes about 1,000 readings a second. A microprocessor then directs a tiny embedded electric motor to adjust the characteristics of the sneaker, enableing it to change the degree of cushioning depending on the surface conditions and the wearer’s running style and foot position. The race for the smartest use of microchips in sporting equipment, it seems, has begun. According to paragraph 6, which of the following is the reason that the damping effect relies solely on energy for Head’s rackets().
案例分析题Set 4Importance of VitaminsVitamins, which come in many different types all of which are quite diverse in chemical configuration and function, can be any of several organic substances that are separated into water-soluble and fat-soluble groups. Originally defined as organic compounds obtainable in a normal diet and capable of maintaining life and promoting growth, vitamins are differrent from carbohydrates, fats, and proteins in function, as well as in the quantities in which organisms require them. So critical are vitamins to a body’s essential strength and health that if they are absent from the diet or not properly absorbed by an organism, a specific deficiency disease may develop.The term vitamin originated from "vitamine," a word first used in the early 19th century to designate a group of compounds considered vital for life (though the term "accessory food factor" sometimes is used interchangeably to refer to these substances). Like other nutrients, vitamin consumption is imperative to keep our bodies functioning properly, and if there is a lack of vitamin consumption, the body will fail to react in a way that’s considered healthy. Lack of vitamin A will result in various disorders that most commonly involve the eye and the tissues around it. One of the earliest symptoms of vitamin A deficiency is nyctalopia, the medical term for night blindness, which causes a visual failure to adapt quickly from light to darkness and an inability to see in the dark. This aspect of vision is normally dependent on rhodopsin, a protein found in the eye that maintains itself only in the presence of vitamin A; in the lack of vitamin A, rhodopsin will malfunction.These earlier symptoms are quite harmless but the side effects can become increasingly serious if not treated early on. If the deficiency is severe and persists, especially in malnourished infants and children, a condition known as xerophthalmia--when the eyes are sensitive to light, the secretion of lubricating tears is stopped, and the eyelids become swollen and develop pus -- may develop. Furthermore, the mucous surfaces of the eye may become eroded, allowing infection to set in, thus leading to ulceration and other destructive changes of the cornea and other structures of the eye, resulting eventually in blindness.Early signs of vitamin A deficiency may also be reflected in changes in the membranes of the mouth, throat, and respiratory and genito-urinary passages where the lining membranes become malnourished and dry and lose their cilia, the tiny hairlike projections that normally help in clearing away foreign particles.The natural immune system is weakened and if insufficient intake of vitamin A is prolonged, the skin may become dry and rough.Vitamin A deficiency may also result in defective bone and teeth formation and in poor general growth.However, an excessive intake of vitamin A can also cause severe damages to the body causing a symptom called "hypervitaminosis A", which happens when a person takes in more than 150 milligrams of vitamin A over a long period of time; the vitamins are stored in the liver and can reach dangerous level because the A vitamins are not employed to make the bodies stronger, but rather, stored as toxic material. Excessive amounts of vitamin A can cause nausea, dryness of skin, blurred vision, drowsiness, and bone pain.Vitamin A can be found in all animal livers, in milk products, and in many yellow and green leafy vegetables which contain carotenes, chemically related substances that are converted to vitamin A in the body. There are various other vitamins that the human body needs in order to survive; the excessive intake of vitamin A, or the lack of intake of other vitamins, causes detriment to the human body--at all times, moderation is key. Which of the following can be inferred from paragraph 5 about vitamin A().
案例分析题Set 4Importance of VitaminsVitamins, which come in many different types all of which are quite diverse in chemical configuration and function, can be any of several organic substances that are separated into water-soluble and fat-soluble groups. Originally defined as organic compounds obtainable in a normal diet and capable of maintaining life and promoting growth, vitamins are differrent from carbohydrates, fats, and proteins in function, as well as in the quantities in which organisms require them. So critical are vitamins to a body’s essential strength and health that if they are absent from the diet or not properly absorbed by an organism, a specific deficiency disease may develop.The term vitamin originated from "vitamine," a word first used in the early 19th century to designate a group of compounds considered vital for life (though the term "accessory food factor" sometimes is used interchangeably to refer to these substances). Like other nutrients, vitamin consumption is imperative to keep our bodies functioning properly, and if there is a lack of vitamin consumption, the body will fail to react in a way that’s considered healthy. Lack of vitamin A will result in various disorders that most commonly involve the eye and the tissues around it. One of the earliest symptoms of vitamin A deficiency is nyctalopia, the medical term for night blindness, which causes a visual failure to adapt quickly from light to darkness and an inability to see in the dark. This aspect of vision is normally dependent on rhodopsin, a protein found in the eye that maintains itself only in the presence of vitamin A; in the lack of vitamin A, rhodopsin will malfunction.These earlier symptoms are quite harmless but the side effects can become increasingly serious if not treated early on. If the deficiency is severe and persists, especially in malnourished infants and children, a condition known as xerophthalmia--when the eyes are sensitive to light, the secretion of lubricating tears is stopped, and the eyelids become swollen and develop pus -- may develop. Furthermore, the mucous surfaces of the eye may become eroded, allowing infection to set in, thus leading to ulceration and other destructive changes of the cornea and other structures of the eye, resulting eventually in blindness.Early signs of vitamin A deficiency may also be reflected in changes in the membranes of the mouth, throat, and respiratory and genito-urinary passages where the lining membranes become malnourished and dry and lose their cilia, the tiny hairlike projections that normally help in clearing away foreign particles.The natural immune system is weakened and if insufficient intake of vitamin A is prolonged, the skin may become dry and rough.Vitamin A deficiency may also result in defective bone and teeth formation and in poor general growth.However, an excessive intake of vitamin A can also cause severe damages to the body causing a symptom called "hypervitaminosis A", which happens when a person takes in more than 150 milligrams of vitamin A over a long period of time; the vitamins are stored in the liver and can reach dangerous level because the A vitamins are not employed to make the bodies stronger, but rather, stored as toxic material. Excessive amounts of vitamin A can cause nausea, dryness of skin, blurred vision, drowsiness, and bone pain.Vitamin A can be found in all animal livers, in milk products, and in many yellow and green leafy vegetables which contain carotenes, chemically related substances that are converted to vitamin A in the body. There are various other vitamins that the human body needs in order to survive; the excessive intake of vitamin A, or the lack of intake of other vitamins, causes detriment to the human body--at all times, moderation is key. Look at the four squares [■] that indicate where the following sentence can be added to the passage. The defective mucous surfaces will have weakened resistance to bacterial invasion, and their susceptibility to various infections increases. Where would the sentence best fit().
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