求09MCM试题

540982016044

论坛里大概找了一下，没找到，谁给传一下

woodwest2

2009 Contest Problems

MCM PROBLEMS

PROBLEM A: Designing a Traffic Circle

Many cities and communities have traffic circles—from large ones with many lanes（车道） in the circle (such as at the Arc de Triomphe in Paris and the Victory Monument in Bangkok) to small ones with one or two lanes in the circle Some of these traffic circles position（放置） a stop sign or a yield sign on every incoming road that gives priority to traffic already in the circle; some position a yield sign in the circle at each incoming road to give priority to incoming traffic; and some position a traffic light on each incoming road (with no right turn allowed on a red light) Other designs may also be possible

The goal of this problem is to use a model to determine how best to control traffic flow in, around, and out of a circle State clearly the objective(s)（目标） you use in your model for ** the optimal（最优的）choice as well as the factors that affect this choice Include a Technical Summary of not more than two double-spaced（两倍行距） pages that explains to a Traffic Engineer how to use your model to help choose the appropriate flow-control（流控制） method for any specific traffic circle That is, summarizethe conditions under which each type of traffic-control method should be used When traffic lights are recommended, explain a method for determining how many seconds each light should remain green (which may vary according to the time of day and other factors) Illustrate how your model works with specific examples



PROBLEM B: Energy and the Cell Phone

This question involves the “energy” consequences of the cell phone revolution Cell phone usage is mushrooming, and many people are using cell phones and giving up their landline telephones What is the consequence of this in terms of electricity use? Every cell phone comes with a battery and a recharger

Requirement 1

Consider the current US, a country of about 300 million people Estimate from available data the number H of households, with m members each, that in the past were serviced by landlines Now, suppose that all the landlines are replaced by cell phones; that is, each of the members of the household has a cell phone Model the consequences of this change for electricity utilization in the current US, both during the transition and during the steady state The analysis should take into account the need for charging the batteries of the cell phones, as well as the fact that cell phones do not last as long as landline phones (for example, the cell phones get lost and break)

Requirement 2

Consider a second “Pseudo US”—a country of about 300 million people with about the same economic status as the current US However, this emerging country has neither landlines nor cell phones What is the optimal way of providing phone service to this country from an energy perspective? Of course, cell phones have many social consequences and uses that landline phones do not allow A discussion of the broad and hidden consequences of having only landlines, only cell phones, or a mixture of the two is welcomed

Requirement 3

Cell phones periodically need to be recharged However, many people always keep their recharger plugged in Additionally, many people charge their phones every night, whether they need to be recharged or not Model the energy costs of this wasteful practice for a Pseudo US based upon your answer to Requirement 2 Assume that the Pseudo US supplies electricity from oil Interpret your results in terms of barrels of oil

Requirement 4

Estimates vary on the amount of energy that is used by various recharger types (TV, DVR, computer peripherals, and so forth) when left plugged in but not charging the device Use accurate data to model the energy wasted by the current US in terms of barrels of oil per day

Requirement 5

Now consider population and economic growth over the next 50 years How might a typical Pseudo US grow? For each 10 years for the next 50 years, predict the energy needs for providing phone service based upon your analysis in the first three requirements Again, assume electricity is provided from oil Interpret your predictions in term of barrels of oil

woodwest2

都给你了啊 都给你了啊 都给你了啊 都给你了啊 都给你了啊  2009mcm

540982016044

谢谢~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

gemengjiao

我也想找2009年的c题的，还没找到

hzl1990@

同谢~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

飞鸿踏雪T

哈。。。。。。

萧邦很忙

好。。。。。。谢谢。。。。

3点一直线

去  不是中文的