首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
Conventional traffic engineering assumes that given no increase in vehicles, more roads mean less congestion. So when planners i
Conventional traffic engineering assumes that given no increase in vehicles, more roads mean less congestion. So when planners i
admin
2018-01-08
21
问题
Conventional traffic engineering assumes that given no increase in vehicles, more roads mean less congestion. So when planners in Seoul tore down a six-lane highway a few years ago and replaced it with a five-mile-long park, many transportation professionals were surprised to learn that the city’s traffic flow had actually improved, instead of worsening. It was like an inverse of Braess’s paradox.
Mathematician Dietrich Braess of Ruhr University Bochum in Germany states that in a network in which all the moving entities rationally seek the most efficient route, adding extra capacity can actually reduce the network’s overall efficiency. The Seoul project inverts this dynamic; closing a highway—that is, reducing network capacity—improves the system’s effectiveness.
Although Braess’s paradox was first identified in the 1960s and is rooted in 1920s economic theory, the concept never gained enough attention in the automobile-oriented U.S. But in the 21st century, economic and environmental problems are bringing new scrutiny to the idea that limiting spaces for cars may move more people more efficiently. A key to this counterintuitive approach to traffic design lies in manipulating the inherent self-interest of all drivers.
A case in point is "The Price of Anarchy in Transportation Networks," published last September in Physical Review Letters by Michael Gastner, a computer scientist at the Santa Fe Institute, and his colleagues. Using hypothetical and real-world road networks, they explain that drivers seeking the shortest route to a given destination eventually reach what is known as the Nash equilibrium, in which no single driver can do any better by changing his or her strategy
unilaterally
. The problem is that the Nash equilibrium is less efficient than the equilibrium reached when drivers act unselfishly—that is, when they coordinate their movements to benefit the entire group.
The "price of anarchy" is a measure of the inefficiency caused by selfish drivers. Analyzing a commute from Harvard Square to Boston Common, the researchers found that the price can be high—selfish drivers typically waste 30 percent more time than they would under "socially optimal" conditions.
The solution hinges on Braess’s paradox, Gastner says. "Selfish drivers can be led to a better solution if you remove some of the network links, in part because closing roads makes it more difficult for individual drivers to choose the best (and most selfish) route."
Which of the following is true about the Braess paradox?
选项
A、People first identified it in the 1920s.
B、It claims that more capacity brings about more efficiency.
C、A mathematician of a university in Seoul came up with it.
D、The Americans didn’t pay much attention to it in the first place.
答案
D
解析
此题为细节分析题。根据第三段第一句:尽管布雷斯悖论根源于20世纪20年代的经济理论,早在20世纪60年代就出现了,然而这个理论却在汽车业发达的美国从没有得到足够重视。因此可排除A项,确定D选项为正确答案。第二段第一句提到德国某大学的科学家提出了这个悖论,排除C项;悖论指出,在一个网络中的所有移动实体都会理性地寻找最有效路径,在这种情况下如果增加系统容量,实际上会降低网络的整体效率,排除B项。
转载请注明原文地址:https://kaotiyun.com/show/bUBZ777K
0
考研英语一
相关试题推荐
AftervisitingWidenerUniversityandlearningaboutitsprogramrequiring300hoursofcommunityserviceinthesurroundingpoo
AftervisitingWidenerUniversityandlearningaboutitsprogramrequiring300hoursofcommunityserviceinthesurroundingpoo
HowdoyouexplaineconomicsinplainEnglish?TheFederalReserveBankofNewYorkhasbeenansweringthequestionwithaneven
HowdoyouexplaineconomicsinplainEnglish?TheFederalReserveBankofNewYorkhasbeenansweringthequestionwithaneven
HowdoyouexplaineconomicsinplainEnglish?TheFederalReserveBankofNewYorkhasbeenansweringthequestionwithaneven
ExtracurricularActivitiesandtheTimeSpentonThemA.Studythefollowingchartscarefullyandwriteanessayof160-200
GreenhouseFlowersCan’tStandtheWindandRainStudythedrawingscarefullyandwriteanessayof160-200words.Youshoul
GivetheSenatesomecredit:inshapingthecurrentimmigration-reformbill,ithascomeupwithoneideathatalmosteverybody
Relativitytheoryhashadaprofoundinfluenceonourpictureofmatterbyforcingustomodifyourconceptofaparticleinan
SpamTextMessageWriteanessayof160-200wordsbasedonthedrawing.Inyouressay,youshould1)describethedrawin
随机试题
设D为长方形区域D={(x,y)|a≤x≤b,0≤y≤1},其中0<a<b,且y2f(x)dσ=3,则∫abf(x)dx=________.
hugeness,huge,hugely,leather,leather’s,leatheryHehasinhisofficea______comfortable___chair.
已知由y2确定y是x的函数,求dy.
A、产伤B、妇科手术C、重体力劳动D、先天发育不良E、慢性咳嗽尿、粪瘘的最主要原因是()
医务人员在一定的医德认识,情感、意志、信念的支配下所采取的行为是指医务人员自觉地克服在履行医德义务中所遇到的困难和障碍的毅力是指
甲国人兰某和乙国人纳某在甲国长期从事跨国人口和毒品贩卖活动,事发后兰某逃往乙国境内,纳某逃人乙国驻甲国领事馆中。兰某以其曾经从事过反对甲国政府的政治活动为由,要求乙国提供庇护。甲乙两国之间没有关于引渡和庇护的任何条约。根据国际法的有关规则和制度,下列哪一项
如果对设备基础有怀疑,可用回弹仪或钢珠撞痕法等对基础的()进行复测。
当事人互负债务的标的物种类不相同的,经双方协商一致也可以抵销。()
一个纷争不已的世界,各种意识形态相互冲突,必然会有一个最文明、最先进、最强大的势力完成统一。这种统一惟一的缺点就是对文化的创造性可能不是太有利,但从老百姓安居乐业,从商业繁荣和世界和平来说,却是无可比拟的。从这段文字中可以推出的是()。
下列叙述中,错误的是()。
最新回复
(
0
)