试题库在线考试题库-历年真题模拟试题及答案-考博英语在线试题测试中心-希赛网

题库

首页 > 题库 > 中国科学院

She ____ the children with her enthusiasm.

What does the italicized word in the sentence “Pete was telling them an anecdote about their mother” mean?

What does the italicized word in the sentence “The aim of this initial meeting is to clarify the issues” mean?

What does the italicized word in the sentence “Her next remark abruptly terminated the conversation” mean?

What does the italicized word in the sentence “The judge invoked an international law that protects refugees” mean?

What does the italicized word in the sentence “He had become the paradigm of the successful man” mean?

We ____ the plan to build another temple as a waste of money.

Government officials should take their responsibilities to serve people ____ cheat them.

____ I wondered if I had missed the train.

Which of the italics is used as a subject?

Our general manager took a deep breath, with the financial problems ____ by the accounting department.

____ an invitation of a company dinner, Mr. Thomas decided to eat outside.

1.机器学习是人工智能及模式识别领域的共同研究热点，其理论和方法已被广泛应用于解决工程应用和科学领域的复杂问题。2010年的图灵奖获得者为哈佛大学的Leslie Valliant教授，其获奖工作之一是建立了概率近似正确（Probably Approximate Correct，PAC）学习理论；2011年的图灵奖获得者为加州大学洛杉矶分校的Judea Pearl教授，其主要贡献为建立了以概率统计为理论基础的人工智能方法。这些研究成果都促进了机器学习的发展和繁荣。机器学习是研究怎样使用计算机模拟或实现人类学习活动的科学，是人工智能中最具智能特征、最前沿的研究领域之一。自20世纪80年代以来，机器学习作为实现人工智能的途径，在人工智能界引起了广泛的兴趣，特别是近十几年来，机器学习领域的研究工作发展很快，它已成为人工智能的重要课题之一。机器学习不仅在基于知识的系统中得到了应用，而且在自然语言理解、非单调推理、机器视觉、模式识别等许多领域也得到了广泛应用。一个系统是否具有学习能力已成为是否具有“智能”的一个标志。机器学习的研究主要分为两类研究方向：第一类是传统机器学习的研究，该类研究主要是研究学习机制，注重探索模拟人的学习机制；第二类是大数据环境下机器学习的研究，该类研究主要是研究如何有效利用信息，注重从巨量数据中获取隐藏的、有效的、可理解的知识。

1. Online learning with expert advice is a fundamental problem of sequential prediction. In this problem, the algorithm has access to a set of n “experts” who make predictions on each day. The goal on each day is to process these predictions, and make a prediction with the minimum cost. After making a prediction, the algorithm sees the actual outcome on that day, updates its state, and then moves on to the next day. An algorithm is judged by how well it does compared to the best expert in the set.The classical algorithm for this problem is the multiplicative weights algorithm, which has been well-studied in many fields since as early as the 1950s. Variations of this algorithm have been applied to and optimized for a broad range of problems, including boosting an ensemble of weak-learners in machine leaning, and approximately solving linear and semi-definite programs. However, every application, to our knowledge, relies on storing weights for every expert and uses Ω(n) memory. There is little work on understanding the memory required to solve the online learning with expert advice problem (or run standard sequential prediction algorithms, such as multiplicative weights) in natural streaming models, which is especially important when the number of experts, as well as the number of days on which the experts make predictions, is large.We initiate the study of the learning with expert advice problem in the streaming setting, and show lower and upper bounds. Our lower bound for i.i.d., random order, and adversarial order streams uses a reduction to a custom-built problem using a novel masking technique, to show a smooth trade-off for regret versus memory. Our upper bounds show novel ways to run standard sequential prediction algorithms in rounds on small pools of experts, thus reducing the necessary memory. For random-order streams, we show that our upper bound is tight up to low order terms. We hope that these results and techniques will have broad applications in online learning, and can inspire algorithms based on standard sequential prediction techniques, like multiplicative weights, for a wide range of other problems in the memory-constrained setting.

Directions: Write an essay of no less than 200 words on the topic given below. Use the space provided on your Answer Sheet II.TOPICWhat marks the maturity (成熟) of a person? Give reasons or use examples to illustrate your points.

Directions: Read the following text carefully and then translate the underlined segments into Chinese. Write your Chinese version in the proper space on your Answer Sheet.In the U.S., citizens tend to rely on electronic media such as TV rather than print media. TV news tends to provide numerous visuals and abbreviated textual information. (1) Although TV news stories pitch “on-the-scene reporting”, and other eye-catching images to viewers, the actual stories are generally so brief that were the reports transcribed into newspaper copy, no single story would have enough text to cover a third of a page. It is remarkable to consider how little information is conveyed between all the exciting visuals. (2) It is also remarkable to stop and think about how inadequately informed citizens may be if their primary source of political knowledge is the picture-rich and data-poor TV evening news.Moreover, because U.S. media companies are primarily privately owned, (3) media professionals are under pressure to present news in an entertaining way in order to expand their audiences and corresponding advertising revenues. Large audiences create higher profits from advertising sales. With a few exceptions, U.S. TV and radio stations are like other businesses: They need to generate money to cover operating costs and make profits. If media professionals are convinced that viewers want entertaining news rather than in-depth details, this assumption affects the kind of news they produce. Not surprisingly, political scientists have found that news coverage of election campaigns tends to focus on the personal lives of candidates rather than on issues, and (4) when issues are reported the emphasis is often on the immediate and most dramatic implications of the issues, not on the historical, long-term, or global dimensions of those issues.At the same time, insofar as television and Internet-based news must be generated quickly, time pressures impede extensive independent investigations. Because U.S. citizens conceptualize news as something occurring by the hour or minute, U.S. media professionals are often putting together news stories under severe time restraints. (5) Some analysts believe that this increases the tendency of reporters to get information from official sources rather than from the reporters’ own independent investigations of newsworthy events. Think about this issue from the standpoint of reporters and editors. If you are a reporter assigned the task of doing a story on a state’s new prison system, for example, you will find it is quicker and easier to get a governor’s press release on the new prison than it is to go to libraries, data banks, and university research centers to investigate the topic on your own. This does not suggest that investigative journalism never occurs; rather, many scholars believe that time pressures tend to encourage the use of information provided by official sources (for example, political leaders and their press secretaries) rather than the collection of facts through ongoing independent research.

The British government turns its attention to the dire state of vocational training. Budget cuts are never pleasant. Yet the past few years have been particularly hard, says Gerry McDonald, the chief executive of New City College in east London. (71)Since 1990, funding for primary and secondary schools has soared. (72) But there has been no such increase in cash for further education, the mostly vocational courses for over-16s.On March 8th Philip Hammond, the chancellor, turned his attention to the sector. After announcing funding to pave the way for new selective grammar schools, he promised a big injection of cash for further education and confirmed a shake-up of the chaotic way in which it is organized. By 2022, colleges will get an additional £ 500m ($ 600m) a year, a 19% increase in the 16- to 19- year-old vocational-education budget.Britain has historically put little emphasis on further education. (73) That may help explain why productivity growth has stalled, and why British youngsters are less literate and numerate than their peers in other rich countries.Employers moan that skilled workers are scarce, especially in industries like engineering and IT. The sector has struggled with shoddy qualifications. The six in ten 18-year-olds who do not take A-levels, academic school-leaving qualifications, are poorly served by a hotchpotch of some 13,000 courses of varying quality.In 2015, the government commissioned Lord Sainsbury to examine the state of technical education in England. (74) Many of the courses are too basic to be of much use. Mr. Hammond now aims to clear up this muddle.Following Lord Sainsbury’s recommendations, the government will introduce 15 subject areas, grouping together topics such as social care or transport and logistics. Students will work towards “T-levels” (for “technical”), developed with firms. (75) The extra funding will provide more work placements. And those who go on to take degree-equivalent qualifications will have access to loans to cover the cost of living.A. Universities have been given the right to raise their incomes by levying tuition fees on students.B. His institution is the result of a merger of three local colleges that have pooled resources in the past year partly to cut costs.C. His report, published in 2016, despaired that a wannabe plumber had to choose between 33 qualifications, offered at three different levels, by five awarding organizations.D. Organizations will compete for the right to award the qualification.E. In 2012 it placed 16th out of 20 member countries of the OECD in a ranking of the proportion of 20- to 45-year-olds who finished education with a vocational qualification.F. Some would rather the reforms offered a broader education to those going down a vocational path, with more of a focus on ensuring competency in maths and English.

Is language, like food, a basic human need without which a child at a critical period of life can be starved and damaged? Judging from the drastic experiment of Frederick I in the thirteenth century, it may be. Hoping to discover what language a child would speak if he heard no mother tongue, he told the nurses to keep silent.All the infants died before the first year. (66) What was missing was good mothering. Without good mothering, in the first year of life especially, the capacity to survive is seriously affected.Today no such severe lack exists as that ordered by Frederick. (67) Most often the reason for this is that the mother is insensitive to the signals of the infant, whose brain is programmed to learn language rapidly. If these sensitive periods are neglected, the ideal time for acquainting skills passes and they might never be learned so easily again. A bird learns to sing and to fly rapidly at the right time, but the process is slow and hard once the critical stage has passed.(68) At twelve weeks a baby smiles and makes vowel-like sounds; at twelve months he can speak simple words and understand simple commands; at eighteen months he has a vocabulary of three to fifty words. At three he knows about 1,000 words which he can put into sentences, and at four his language differs from that of his parents in style rather than grammar.(69) What is special about man’s brain, compared with that of the monkey, is the complex system which enables a child to connect the sight and feel of, say, a toy-bear with the sound pattern “toy-bear”. (70)A. Sensitivity to the child’s non-verbal signals is essential to the growth and development of language.B. But clearly there was more than lack of language here.C. Recent evidence suggests that an infant is born with the capacity to speak.D. Nevertheless, some children are still backward in speaking.E. And even more incredible is the young brain’s ability to pick out an order in language from the mixture of sound around him, to analyze, to combine and recombine the parts of a language in new ways.F. Experts suggested that speech stages are reached in a fixed sequence and at a constant age, but there are cases where speech has started late in a child who eventually turns out to be of high IQ.

No doubt you know several folks with perfectly respectable IQs who repeatedly make poor decisions. The behavior of such people tells us that we are missing something important by treating intelligence as if it encompassed all cognitive abilities. I coined the term “dysrationalia”, meaning the inability to think and behave rationally despite having adequate intelligence, to draw attention to a large domain of cognitive life that intelligence tests fail to assess. Although most people recognize that IQ tests do not measure every important mental faculty, we behave as if they do. We have an implicit assumption that intelligence and rationality go together—or else why would we be so surprised when smart people do foolish things?IQ tests do not measure dysrationalia, but there are ways to measure dysrationalia and ways to correct it. Decades of research in cognitive psychology have suggested two causes of dysrationalia. One is a processing problem, the other a content problem. Much is known about both of them.The processing problem comes about because we tend to be cognitive misers. When approaching a problem, we can choose from any of several cognitive mechanisms. Some mechanisms have great computational power, letting us solve many problems with great accuracy, but they are slow, require much concentration and can interfere with other cognitive tasks. Others are comparatively low in computational power, but they are fast, require little concentration and do not interfere with other ongoing cognition. Humans are cognitive misers because our basic tendency is to default to the processing mechanisms that require less computational effort, even when they are less accurate.The second source of dysrationalia is a content problem. We need to acquire specific knowledge to think and act rationally. Harvard cognitive scientist David Perkins coined the term “mindware” to refer to the rules, data, procedures, strategies and other cognitive tools (knowledge of probability, logic and scientific inference) that must be retrieved from memory to think rationally. The absence of this knowledge creates a mindware gap—again, something that is not tested on typical intelligence tests.My goal in proposing the term “dysrationalia” is to separate intelligence from rationality, a trait that IQ tests do not measure. The concept of dysrationalia, and the empirical evidence indicating that the condition is not rare, should help create a conceptual space in which we value abilities at least as important as those currently measured in IQ tests.60. People with “dysrationalia” often .61. The author believes that IQ tests .62. One cause of dysrationalia is that .63. According to David Perkins, “mindware” means .64. The author coined the term “dysrationalia” in order to .65. An appropriate title of this passage could be .

Sleep deprivation is a quick and efficient way to treat depression. It works 60 to 70 percent of the time—far better than existing drugs—but the mood boost usually lasts only until the patient falls asleep. As an ongoing treatment, sleep deprivation is impractical, but researchers have been studying the phenomenon in an effort to uncover the cellular mechanisms behind depression and remission. Now a team at Tufts University has pinpointed glia as the key players.The researchers previously found that astrocytes, a star-shaped type of glial cell, regulate the brain chemicals involved in sleepiness. During our waking hours, astrocytes continuously release the neurotransmitter adenosine, which builds up in the brain and causes “sleep pressure”, the feeling of sleepiness and its related memory and attention impairments. The neurotransmitter causes this pressure by binding to adenosine receptors on the outside of neurons like a key fitting into a lock. As more adenosine builds up, more receptors are triggered, and the urge to sleep gets stronger.In the new study, published online January 15 in the journal Translational Psychiatry, the scientists investigated whether this process is responsible for the antidepressant effects of sleep deprivation. Mice with depressive-like symptoms were administered three doses of a compound that triggers adenosine receptors, thus mimicking sleep deprivation. Although the mice continued to sleep normally, after 12 hours they showed a rapid improvement in mood and behavior, which lasted for 48 hours.The results confirm that the adenosine buildup is responsible for the antidepressant effects of a lack of sleep. This finding points to a promising target for new drug development because it suggests that mimicking sleep deprivation chemically may offer the antidepressant benefits without the unwanted side effects of actually skipping sleep. Such an intervention could offer immediate relief from depression, in stark contrast with traditional antidepressants, which take six to eight weeks to kick in.The study may also have implications beyond depression and sleep regulation, according to Dustin Hines, lead author and a postdoctoral fellow at Tufts. “For many years, neuroscientists focused almost exclusively on neurons, whereas the role of glia was neglected,” Hines says. “We now know that glia play an important role in the control of brain function and have the potential to aid in the development of new treatments for many illnesses, including depression and sleep disorders.”54. Sleep deprivation as a method to treat depression is impractical because .55. What does the underlined word “remission” in Para. 1 probably mean?56. What is true of astrocyte?57. Dustin Hines and his colleagues did the study in order to .58. What did Dustin Hines and his colleagues’ study suggest?59. What can we infer from the new research about depression?

暂未登录

学员用户尊享特权

老师批改作业做题助教答疑学员专用题库高频考点梳理

上一页 2 3 4 5 6 7 下一页