学习啦【英语文摘】 编辑：韦彦 发布时间：2016-08-30
Essay-Grading Software Offers Professors a Break
[A] Imagine taking a college exam, and, instead of handing in a blue book and getting a grade from a professor a few weeks later, clicking the “send” button when you are done and receiving a grade back instantly, your essay scored by a software program. And then, instead of being done with that exam, imagine that the system would immediately let you rewrite the test to try to improve your grade.
[B]EdX, the nonprofit enterprise founded by Harvard and the Massachusetts Institute of Technology(MIT)to offer courses on the Internet, has just introduced such a system and will make its automated(自动的)software available free on the Web to any institution that wants to use it. The software uses artificial intelligence to grade student essays and short written answers, freeing professors for other tasks.
[C] The new service will bring the educational consortium(联盟)into a growing conflict over the role of automation in education. Although automated grading systems for multiple-choice and true-false tests are now widespread, the use of artificial intelligence technology to grade essay answers has not yet received widespread acceptance by educators and has many critics.
[D] Anant Agarwal, an electrical engineer who is president of EdX, predicted that theinstant-grading software would be a useful teaching tool, enabling students to take tests and write essays over and over and improve the quality of their answers. He said the technology would offer distinct advantages over the traditional classroom system, where students often wait days or weeks for grades. “There is a huge value in leaning with instant feedback,” Dr. Agarwal said. “Students are telling us they learn much better with instant feedback.”
[E] But skeptics(怀疑者)say the automated system is no match for live teachers. One longtime critic, Les Perelman, has drawn national attention several times for putting together nonsense essays that have fooled software grading programs into giving high marks. He has also been highly critical of studies claiming that the software compares well to human graders.
[F] He is among a group of educators who last month began circulating a petition(呼吁)opposing automated assessment software. The group, which calls itself Professsionals Against MachineScoring of Student Essays in High-Stakes Assessment, has collected nearly 2,000 signatures, including some from famous people like Noam Chomsky.
[G] “Let’s face the realities of automatic essay scoring,” the group’s statement reads in part. “Computers cannot ‘read’.They cannot measure the essentials of effective written communication: accuracy, reasoning, adequacy of evidence, good sense, ethical(伦理的)position, convincing argument, meaningful organization, and clarity, among others.”.
[H] But EdX expects its software to be adopted widely by schools and universities. It offers free online classes from Harvard, MIT and the University of Californian-Berkeley; this fall, it will add classes from Wellesley, Georgetown and the University of Texas. In all, 12 universities participate in EdX, which offers certificates for course completion and has said that it plans to continue to expand next year, including adding international schools.
[I] The EdX assessment tool requires human teachers, or graders, to first grade 100 essays or essay questions. The system then uses a variety of machine-learning techniques to train itself to be able to grade any number of essays or answers automatically and almost instantly. The software will assign a grade depending on the scoring system created by the teacher, whether it is a letter grade or numerical(数字的)rank.
[J] EdX is not the first to use the automated assessment technology, which dates to early computers in the 1960s. There is now a range of companies offering commercial programs to grade written test answers, and four states—Louisiana, North Dakota, Utah and West Virginia—are using some form of the technology in secondary schools. A fifth, Indiana, has experimented with it. In some cases the software is used as a “second reader,”to check the reliability of the human graders.
[K] But the growing influence of the EdX consortium to set standards is likely to give the technology a boost. On Tuesday, Stanford announced that is would work with EdX to develop a joint educational system that will make use of the automated assessment technology.
[L] Two start-ups, Coursera and Udacity, recently founded by Stanford faculty members to create “massive open online courses,”or MOOCs, are also committed to automated assessment systems because of the value of instant feedback. “It allows students to get immediate feedback on their work, so that learning turns into a game, with students naturally gravitating(吸引) toward resubmitting the work until they get it right,” said Daphne Koller, a computer scientist and a founder of Coursera.
[M] Last year the Hewlett Foundation, a grant-making organization set up by one of the Hewlett-Packard founders and his wife, sponsored two $100,000 prizes aimed at improving software that grades essays and short answers. More than 150 teams entered each category. A winner of one of the Hewlett contests, Vik Paruchuri, was hired by EdX to help design its assessment software.
[N] “One of our focuses is to help kids learn how to think critically,”said Victor Vuchic, a program officer at the Hewlett Foundation. “It’s probably impossible to do that with multiple-choice tests. The challenge is that this requires human graders, and so they cost a lot more and they take a lot more time.”
[O] Mark D. Shermis, a professor at the University of Akron in Ohio, supervised the Hewlett Foundation’s contest on automated essay scoring and wrote a paper about the experiment. In his view, the technology—though imperfect—has a place in educational settings.
[P] With increasingly large classes, it is impossible for most teachers to give students meaningful feedback on writing assignments, he said. Plus, he noted, critics of the technology have tended to come from the nation’s best universities, where the level of teaching is much better than at most schools.
[Q]“Often they come from very famous institutions where, in fact, they do a much better job of providing feedback than a machine ever could,”Dr. Shermis said. “There seems to be a lack of appreciation of what is actually going on in the real world.”
46. Some professionals in education are collecting signatures to voice their opposition to automated essay grading.
47. Using software to grade students’ essays saves teachers time for other work.
48. The Hewlett contests aim at improving essay grading software.
49. Though the automated grading system is widely used in multiple-choice tests, automated essay grading is still criticized by many educators.
50. Some people don’t believe the software grading system can do as good a job as human graders.
51. Critics of automated essay scoring do not seem to know the true realities in less famous universities.
52. Critics argue many important aspects of effective writing cannot be measured by computer rating programs.
53. As class size grows, most teachers are unable to give students valuable comments as to how to improve their writing.
54. The automated assessment technology is sometimes used to double check the work of human graders.
55. Students find instant feedback helps improve their learning considerably.
waste not, want not
feeding the 9 billion: the tragedy of waste
[a] by 2075, the united nations' mid-range projection for global population is about 9.5 billion. this means that there could be an extra three billion mouths to feed by the end of the century, a period in which substantial changes are anticipated in the wealth, calorie intake and dietary preferences of people in developing countries across the world. such a projection presents mankind with wide-ranging social, economic, environmental and political issues that need to be addressed today to ensure a sustainable future for all. one key issue is how to produce more food in a world of finite resources.
[b] today, we produce about four billion metric tonnes of food per year. yet due to poor practices in harvesting, storage and transportation, as well as market and consumer wastage, it is estimated that 30-50% of all food produced never reaches a human stomach. furthermore, this figure does not reflect the fact that large amounts of land, energy, fertilisers and water have also been lost in the production of foodstuffs which simply end up as waste. this level of wastage is a tragedy that cannot continue if we are to succeed in the challenge of sustainably meeting our future food demands.
where food waste happens
[c] in 2010,the institution of mechanical engineers identified three principal emerging population groups across the world, based on characteristics associated with their current and projected stage of economic development.
• fully developed, mature, post-industrial societies, such as those in europe, characterised by stable or declining populations which are increasing in age.
• late-stage developing nations that are currently industrialising rapidly, for example china, which will experience declining rates of population growth, coupled with increasing affluence (富裕)and age profile.
• newly developing countries that are beginning to industrialise, primarily in africa, with high to very high population growth rates, and characterised by a predominantly young age profile.
[d] each group over the coming decades will need to address different issues surrounding food production, storage and transportation, as well as consumer expectations, if we are to continue to feed all our people.
[e] in less-developed countries, such as those of sub-saharan africa and south-east asia, wastage tends to occur primarily at the farmer-producer end of the supply chain. inefficient harvesting, inadequate local transportation and poor infrastructure (基础设施)mean that produce is frequently handled inappropriately and stored under unsuitable farm site conditions.
[f] in mature, fully developed countries such as the uk, more-efficient farming practices and better transport, storage and processing facilities ensure that a larger proportion of the food produced reaches markets and consumers. however, characteristics associated with modern consumer culture mean produce is often wasted through retail and customer behaviour.
[g] major supermarkets, in meeting consumer expectations, will often reject entire crops of perfectly edible fruit and vegetables at the farm because they do not meet exacting marketing standards for their physical characteristics, such as size and appearance.
[h] of the produce that does appear in the supermarket, commonly used sales promotions frequently encourage customers to purchase excessive quantities which, in the case of perishable foodstuffs, inevitably generate wastage in the home. overall between 30% and 50% of what has been bought in developed countries is thrown away by the purchaser.
better use of our finite resources
[i] wasting food means losing not only life-supporting nutrition but also precious resources, including land, water and energy. as a global society, therefore, tackling food waste will help contribute towards addressing a number of key resource issues.
[j] land usage: over the last five decades, improved farming techniques and technologies have helped to significantly increase crop yields along with a 12% expansion of farmed land use. however, a further increase in farming area without impacting unfavourably on what remains of the world's natural ecosystems appears unlikely. the challenge is that an increase in animal-based production will require more land and resources, as livestock (牲畜)farming demands extensive land use.
[k] water usage: over the past century, human use of fresh water has increased at more than double the rate of population growth. currently about 3.8 trillion m3of water is used by humans per year. about 70% of this is consumed by the global agriculture sector, and the level of use will continue to rise over the coming decades.
[l] better irrigation can dramatically improve crop yield and about 40% of the world's food supply is currently derived from irrigated land. however, water used in irrigation is often sourced unsustainably.in processing foods after the agricultural stage, there are large additional uses of water that need to be tackled in a world of growing demand. this is particularly crucial inthe case of meat production, where beef uses about 50 times more water than vegetables. in the future, more effective washing techniques, management procedures, and recycling and purification of water will be needed to reduce wastage.
[m]energy usage: energy is an essential resource across the entire food production cycle, with estimates showing an average of 7-10 calories of input being required in the production of one calorie of food. this varies dramatically depending on crop, from three calories for plant crops to 35 calories in the production of beef. since much of this energy comes from the utilisation of fossil fuels, wastage of food potentially contributes to unnecessary global warming as well as inefficient resource utilisation.
[n] in the modem industrialised agricultural process—which developing nations are moving towards in order to increase future yields—energy usage in the making and application of fertilisers and pesticides represents the single biggest component. wheat production takes 50% of its energy input for these two items alone. indeed, on a global scale, fertiliser manufacturing consumes about 3-5% of the world's annual natural gas supply. with production anticipated to increase by 25% between now and 2030, sustainable energy sourcing will become an increasingly major issue. energy to power machinery, both on the farm and in the storage and processing facilities, adds to the energy total, which currently represents about 3.1% of annual global energy consumption.
[o] rising population combined with improved nutrition standards and shifting dietary preferences will exert pressure for increases in global food supply. engineers, scientists and agriculturalists have the knowledge, tools and systems that will assist in achieving productivity increases. however, pressure will grow on finite resources of land, energy and water. the potential to provide 60-100% more food by simply eliminating losses, while simultaneously freeing up land, energy and water resources for other uses, is an opportunity that should not be ignored. in order to begin tackling the challenge, the institution recommends that:
•the un food and agriculture organisation work with the international engineering community to ensure governments of developed nations put in place programmes that transfer engineering knowledge, design know-how, and suitable technology to newly developing countries. this will help improve produce handling in the harvest, and immediate post-harvest stages of food production.
• governments of rapidly developing countries incorporate waste minimisation thinking into the transport infrastructure and storage facilities currently being planned, engineered and built.
• governments in developed nations devise and implement policy that changes consumer expectations. these should discourage retailers from wasteful practices that lead to the rejection of food on the basis of cosmetic characteristics, and losses in the home due to excessive purchasing by consumers.
46. elimination of waste alone can potentially provide over sixty percent more food for the growing world population.
47. the production and application of fertilisers and pesticides account for the largest part of energy use in the modern industrialised agricultural process.
48. consumers in developed countries throw away nearly half of their food purchases because they tend to buy in excessive quantities.
49. it is recommended that engineering knowledge and suitable technology in developed countries be introduced to developing countries to improve produce handling in the harvest.
50. the predicted global population growth means that ways have to be found to produce more food with finite resources.
51. a further expansion of farming area will adversely impact on the world's natural ecosystems.
52. perfectly eatable fruit and vegetable crops often fail to reach supermarkets due to their size or physical appearance.
53. poor practices in harvesting, storage and transportation have resulted in a waste of much of the food we produce and thus a waste of land and resources.
54. food waste in less-developed countries happens mainly at the producers' end.
55. beef consumes far more water to produce than vegetables.