Imagine taking a university exam in your own home, under the watchful eye of a webcam or with software profiling your keystrokes or your syntax to see whether it really is you answering the questions. Online university courses have become the Next Big Thing for higher education, particularly in the United States, where millions of students have signed up for courses from some of the most upmarket universities. With spiralling costs and student loan debts crossing the trillion dollar barrier this year, the online university has been seen as a way of reaching many more people for much less money. But a major stumbling block has been how such digital courses are assessed. When students are at home how do you know whether they are cheating? How do you know the identity of the person answering the questions? For the online courses to gain value, they need a credible way of assessing students and an important part of that is preventing fraud. The Open University in the U. K. has been a pioneer of distance learning. "It's a common problem across the sector—how do you know that the individual taking the exam is the right person?" says Peter Taylor, chair of the Open University's academic conduct group. "The student's computer would be locked down so that it can't use other materials. If you've got an appropriate webcam—that can provide you with effective invigilation. " says Prof. Taylor. This still raises the question about how you know who is sitting the exam. "There are various ways you can identify a person," says Prof. Taylor. "One system we looked at meant that you had to type in a particular phrase—and the rate and the particular way you type is effectively a signature of the individual. " These are not distant-horizon ideas—Prof. Taylor says he would expect such technology to be in place within the next five years. He also says that there is no reason to think more people would necessarily cheat online. EdX, an online university project set up earlier this year by the Massachusetts Institute of Technology and Harvard, wants to make more use of the exam hall rather than less. Students taking edX online courses will be able to sit their final exams in an international network of test centres, run by Pearson Vue. These will be formally supervised on-screen exams, using the edX website, and those who pass will receive a "proctored certificate", showing it has been achieved in an invigilated setting. Such online testing techniques are going to have an impact on the traditional university course too, he says. But this volume of testing depends on automated marking—and will mean a limit on the range of subjects and type of questions that can be examined. A computer is going to struggle to mark an essay on irony. That's the challenge for another of the most significant online course providers, Coursera, set up by Stanford academics and backed by Silicon Valley investors. It has attracted students remarkably quickly—1.6 million have signed up in the first year, taking courses from more than 30 top universities. When the University of London's international section joined last month, 9,000 students signed up in the first 24 hours. But how can such large numbers of candidates be reliably marked? Coursera's co-founder Daphne Koller says trying to find a way to assess so many students is "part of the learning process". She says automatic marking can generate a score or a grade, but students want human feedback. And there isn't any technology that can judge whether an essay has really connected with a question. The Open University's Prof. Taylor says their own experiments have shown that any software for assessing free-text answers requires a large amount of human intervention. Coursera has been experimenting with peer assessment, where students grade each other's work, following guidelines set by the teacher. This allows for the marking capacity to grow with the class size—but it also depends on the reliability of fellow students. These online courses are also being discussed online—and blogs from students refer to disagreements over marking. Martin Bean, vice chancellor of the Open University, said: "There is no doubt that this is the 'web moment' for higher education and a battle is shaping up for growing student numbers on global courses online. However this is a battle which will be about brands and the market ability of the providers but also, crucially, about quality of teaching and credibility."
单选题
What can be inferred from the 2nd and 3rd paragraphs?