2023年12月7日发(作者:罗庄区数学试卷九年级)

2014 MCM Problems

PROBLEM A: The Keep-Right-Except-To-Pass Rule

In countries where driving automobiles on the right is the rule (that is, USA,

China and most other countries except for Great Britain, Australia, and some

former British colonies), multi-lane freeways often employ

a rule that

requires drivers to drive in the right-most lane unless they are

passing another vehicle, in which case they move one lane to the left,

pass, and return to their former travel lane.

Build and analyze a mathematical model to analyze the performance of this rule

in light and heavy traffic. You may wish to examine tradeoffs between traffic

flow and safety, the role of under- or over-posted speed limits (that is, speed

limits that are too low or too high), and/or other factors that may not be

explicitly called out in this problem statement. Is this rule effective in promoting

better traffic flow? If not, suggest and analyze alternatives (to include possibly

no rule of this kind at all) that might promote greater traffic flow, safety, and/or

other factors that you deem important.

In countries where driving automobiles on the left is the norm, argue whether

or not your solution can be carried over with a simple change of orientation, or

would additional requirements be needed.

Lastly, the rule as stated above relies upon human judgment for compliance. If

vehicle transportation on the same roadway was fully under the control of an

intelligent system – either part of the road network or imbedded in the design

of all vehicles using the roadway – to what extent would this change the results

of your earlier analysis?

PROBLEM B: College Coaching Legends

Sports Illustrated, a magazine for sports enthusiasts, is looking for the ―best all

time college coach‖ male or female for the previous century. Build a

mathematical model to choose the

best college coach or coaches (past or

present) from among either male or female coaches in such sports as college

hockey or field hockey, football, baseball or softball, basketball, or soccer. Does

it make a difference which time line horizon that you use in your analysis, i.e.,

does coaching in 1913 differ from coaching in 2013? Clearly articulate your

metrics for assessment. Discuss how your model can be applied in general

across both genders and all possible sports. Present your model’s top 5 coaches

in each of 3 different sports.

In addition to the MCM format and requirements, prepare a 1-2 page article

for

Sports Illustrated that explains your results and includes a non-technical

explanation of your mathematical model that sports fans will understand. 2013 MCM Problems

PROBLEM A: The Ultimate Brownie Pan

When baking in a rectangular pan heat is concentrated in the 4 corners and the

product gets overcooked at the corners (and to a lesser extent at the edges). In

a round pan the heat is distributed evenly over the entire outer edge and the

product is not overcooked at the edges. However, since most ovens are

rectangular in shape using round pans is not efficient with respect to using the

space in an oven. Develop a model to show the distribution of heat across the

outer edge of a pan for pans of different shapes - rectangular to circular and

other shapes in between.

Assume

1. A width to length ratio of

W/L for the oven which is rectangular in shape.

2. Each pan must have an area of

A.

3. Initially two racks in the oven, evenly spaced.

Develop a model that can be used to select the best type of pan (shape) under

the following conditions:

1. Maximize number of pans that can fit in the oven (N)

2. Maximize even distribution of heat (H) for the pan

3. Optimize a combination of conditions (1) and (2) where weights p and (1-

p)

are assigned to illustrate how the results vary with different values

of

W/L and

p.

In addition to your MCM formatted solution, prepare a one to two page

advertising sheet for the new Brownie Gourmet Magazine highlighting your

design and results.

PROBLEM B: Water, Water, Everywhere

Fresh water is the limiting constraint for development in much of the world.

Build a mathematical model for determining an effective, feasible, and

cost-efficient water strategy for 2013 to meet the projected water needs of

[pick one country from the list below] in 2025, and identify the best water

strategy. In particular, your mathematical model must address storage and

movement; de-salinization; and conservation. If possible, use your model to

discuss the economic, physical, and environmental implications of your strategy.

Provide a non-technical position paper to governmental leadership outlining

your approach, its feasibility and costs, and why it is the ―best water strategy

choice.‖

Countries: United States, China, Russia, Egypt, or Saudi Arabia 2012 MCM Problems

PROBLEM A: The Leaves of a Tree

\"How much do the leaves on a tree weigh?\" How might one estimate the actual

weight of the leaves (or for that matter any other parts of the tree)? How might

one classify leaves? Build a mathematical model to describe and classify leaves.

Consider and answer the following:

• Why do leaves have the various shapes that they have?

• Do the shapes ―minimize‖ overlapping individual shadows that are cast, so as

to maximize exposure? Does the distribution of leaves within the ―volume‖ of

the tree and its branches effect the shape?

• Speaking of profiles, is leaf shape (general characteristics) related to tree

profile/branching structure?

• How would you estimate the leaf mass of a tree? Is there a correlation

between the leaf mass and the size characteristics of the tree (height, mass,

volume defined by the profile)?

In addition to your one page summary sheet prepare a one page letter to an

editor of a scientific journal outlining your key findings.

PROBLEM B: Camping along the Big Long River

Visitors to the Big Long River (225 miles) can enjoy scenic views and exciting

white water rapids. The river is inaccessible to hikers, so the only way to enjoy

it is to take a river trip that requires several days of camping. River trips all start

at First Launch and exit the river at Final Exit, 225 miles downstream.

Passengers take either oar- powered rubber rafts, which travel on average 4

mph or motorized boats, which travel on average 8 mph. The trips range from 6

to 18 nights of camping on the river, start to finish.. The government agency

responsible for managing this river wants every trip to enjoy a wilderness

experience, with minimal contact with other groups of boats on the river.

Currently,

X trips travel down the Big Long River each year during a six month

period (the rest of the year it is too cold for river trips). There are

Y camp sites

on the Big Long River, distributed fairly uniformly throughout the river corridor.

Given the rise in popularity of river rafting, the park managers have been asked

to allow more trips to travel down the river. They want to determine how they

might schedule an optimal mix of trips, of varying duration (measured in nights

on the river) and propulsion (motor or oar) that will utilize the campsites in the best way possible. In other words, how many more boat trips could be added to

the Big Long River’s rafting season? The river managers have hired you to

advise them on ways in which to develop the best schedule and on ways in

which to determine the carrying capacity of the river, remembering that no two

sets of campers can occupy the same site at the same time. In addition to your

one page summary sheet, prepare a one page memo to the managers of the

river describing your key findings.

2011 MCM Problems

PROBLEM A: Snowboard Course

Determine the shape of a snowboard course (currently known as a ―halfpipe‖)

to maximize the production of ―vertical air‖ by a skilled snowboarder.

\"Vertical air\" is the maximum vertical distance above the edge of the halfpipe.

Tailor the shape to optimize other possible requirements, such as maximum

twist in the air.

What tradeoffs may be required to develop a ―practical‖ course?

PROBLEM B: Repeater Coordination

The VHF radio spectrum involves line-of-sight transmission and reception. This

limitation can be overcome by ―repeaters,‖ which pick up weak signals, amplify

them, and retransmit them on a different frequency. Thus, using a repeater,

low-power users (such as mobile stations) can communicate with one another

in situations where direct user-to-user contact would not be possible. However,

repeaters can interfere with one another unless they are far enough apart or

transmit on sufficiently separated frequencies.

In addition to geographical separation, the ―continuous tone-coded squelch

system‖ (CTCSS), sometimes nicknamed ―private line‖ (PL), technology can be

used to mitigate interference problems. This system associates to each

repeater a separate subaudible tone that is transmitted by all users who wish to

communicate through that repeater. The repeater responds only to received

signals with its specific PL tone. With this system, two nearby repeaters can

share the same frequency pair (for receive and transmit); so more repeaters

(and hence more users) can be accommodated in a particular area.

For a circular flat area of radius 40 miles radius, determine the minimum

number of repeaters necessary to accommodate 1,000 simultaneous users.

Assume that the spectrum available is 145 to 148 MHz, the transmitter

frequency in a repeater is either 600 kHz above or 600 kHz below the receiver

frequency, and there are 54 different PL tones available.

How does your solution change if there are 10,000 users?

Discuss the case where there might be defects in line-of-sight propagation

caused by mountainous areas.

2010 MCM Problems

PROBLEM A: The Sweet Spot

Explain the ―sweet spot‖ on a baseball bat.

Every hitter knows that there is a spot on the fat part of a baseball bat where maximum power

is transferred to the ball when hit. Why isn’t this spot at the end of the bat? A simple

explanation based on torque might seem to identify the end of the bat as the sweet spot, but

this is known to be empirically incorrect. Develop a model that helps explain this empirical

finding.

Some players believe that ―corking‖ a bat (hollowing out a cylinder in the head of the bat and

filling it with cork or rubber, then replacing a wood cap) enhances the ―sweet spot‖ effect.

Augment your model to confirm or deny this effect. Does this explain why Major League

Baseball prohibits ―corking‖?

Does the material out of which the bat is constructed matter? That is, does this model predict

different behavior for wood (usually ash) or metal (usually aluminum) bats? Is this why Major

League Baseball prohibits metal bats?

PROBLEM B: Criminology

In 1981 Peter Sutcliffe was convicted of thirteen murders and subjecting a number of other

people to vicious attacks. One of the methods used to narrow the search for Mr. Sutcliffe was to

find a ―center of mass‖ of the locations of the attacks. In the end, the suspect happened to live

in the same town predicted by this technique. Since that time, a number of more sophisticated

techniques have been developed to determine the ―geographical profile‖ of a suspected serial criminal based on the locations of the crimes.

Your team has been asked by a local police agency to develop a method to aid in their

investigations of serial criminals. The approach that you develop should make use of at least

two different schemes to generate a geographical profile. You should develop a technique to

combine the results of the different schemes and generate a useful prediction for law

enforcement officers. The prediction should provide some kind of estimate or guidance about

possible locations of the next crime based on the time and locations of the past crime scenes. If

you make use of any other evidence in your estimate, you must provide specific details about

how you incorporate the extra information. Your method should also provide some kind of

estimate about how reliable the estimate will be in a given situation, including appropriate

warnings.

In addition to the required one-page summary, your report should include an additional

two-page executive summary. The executive summary should provide a broad overview of the

potential issues. It should provide an overview of your approach and describe situations when it

is an appropriate tool and situations in which it is not an appropriate tool. The executive

summary will be read by a chief of police and should include technical details appropriate to the

intended audience

2009 MCM Problems

PROBLEM A: Designing a Traffic Circle

Many cities and communities have traffic circles—from large ones with many

lanes 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 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) you use

in your model for making the optimal choice as well as the factors that affect

this choice. Include a Technical Summary of not more than two double-spaced

pages that explains to a Traffic Engineer how to use your model to help choose

the appropriate flow-control method for any specific traffic circle. That is,

summarize the 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

m 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.

2008 MCM Problems

PROBLEM A: Take a Bath

Consider the effects on land from the melting of the north polar ice cap due to the predicted

increase in global temperatures. Specifically, model the effects on the coast of Florida every ten

years for the next 50 years due to the melting, with particular attention given to large

metropolitan areas. Propose appropriate responses to deal with this. A careful discussion of the

data used is an important part of the answer.

PROBLEM B: Creating Sudoku Puzzles

Develop an algorithm to construct Sudoku puzzles of varying difficulty. Develop metrics to

define a difficulty level. The algorithm and metrics should be extensible to a varying number of

difficulty levels. You should illustrate the algorithm with at least 4 difficulty levels. Your

algorithm should guarantee a unique solution. Analyze the complexity of your algorithm. Your

objective should be to minimize the complexity of the algorithm and meet the above

requirements.

2007 MCM Problems

PROBLEM A: Gerrymandering

The United States Constitution provides that the House of Representatives shall be composed

of some number (currently 435) of individuals who are elected from each state in proportion to

the state\'s population relative to that of the country as a whole. While this provides a way of determining how many representatives each state will have, it says nothing about how the

district represented by a particular representative shall be determined geographically. This

oversight has led to egregious (at least some people think so, usually not the incumbent)

district shapes that look \"unnatural\" by some standards.

Hence the following question: Suppose you were given the opportunity to draw congressional

districts for a state. How would you do so as a purely \"baseline\" exercise to create the

\"simplest\" shapes for all the districts in a state? The rules include only that each district in the

state must contain the same population. The definition of \"simple\" is up to you; but you need to

make a convincing argument to voters in the state that your solution is fair. As an application of

your method, draw geographically simple congressional districts for the state of New York.

PROBLEM B: The Airplane Seating Problem

Airlines are free to seat passengers waiting to board an aircraft in any order whatsoever. It has

become customary to seat passengers with special needs first, followed by first-class

passengers (who sit at the front of the plane). Then coach and business-class passengers are

seated by groups of rows, beginning with the row at the back of the plane and proceeding

forward.

Apart from consideration of the passengers\' wait time, from the airline\'s point of view, time is

money, and boarding time is best minimized. The plane makes money for the airline only when

it is in motion, and long boarding times limit the number of trips that a plane can make in a day.

The development of larger planes, such as the Airbus A380 (800 passengers), accentuate the

problem of minimizing boarding (and deboarding) time.

Devise and compare procedures for boarding and deboarding planes with varying numbers of

passengers: small (85-210), midsize (210-330), and large (450-800).

Prepare an executive summary, not to exceed two single-spaced pages, in which you set out

your conclusions to an audience of airline executives, gate agents, and flight crews.

Note: The 2 page executive summary is to be included IN ADDITION to the reports required by

the contest guidelines.

An article appeared in the NY Times Nov 14, 2006 addressing procedures currently being

followed and the importance to the airline of finding better solutions. The article can be seen

at:/2006/11/14/business/

2006 MCM Problems

PROBLEM A: Positioning and Moving Sprinkler Systems for Irrigation

There are a wide variety of techniques available for irrigating a field. The technologies range

from advanced drip systems to periodic flooding. One of the systems that is used on smaller

ranches is the use of \"hand move\" irrigation systems. Lightweight aluminum pipes with

sprinkler heads are put in place across fields, and they are moved by hand at periodic intervals

to insure that the whole field receives an adequate amount of water. This type of irrigation

system is cheaper and easier to maintain than other systems. It is also flexible, allowing for use

on a wide variety of fields and crops. The disadvantage is that it requires a great deal of time

and effort to move and set up the equipment at regular intervals.

Given that this type of irrigation system is to be used, how can it be configured to minimize the

amount of time required to irrigate a field that is 80 meters by 30 meters? For this task you are

asked to find an algorithm to determine how to irrigate the rectangular field that minimizes the

amount of time required by a rancher to maintain the irrigation system. One pipe set is used in

the field. You should determine the number of sprinklers and the spacing between sprinklers,

and you should find a schedule to move the pipes, including where to move them.

A pipe set consists of a number of pipes that can be connected together in a straight line. Each

pipe has a 10 cm inner diameter with rotating spray nozzles that have a 0.6 cm inner diameter.

When put together the resulting pipe is 20 meters long. At the water source, the pressure is

420 Kilo- Pascal\'s and has a flow rate of 150 liters per minute. No part of the field should

receive more than 0.75 cm per hour of water, and each part of the field should receive at least

2 centimeters of water every 4 days. The total amount of water should be applied as uniformly

as possible

PROBLEM B: Wheel Chair Access at Airports

One of the frustrations with air travel is the need to fly through multiple airports, and each stop

generally requires each traveler to change to a different airplane. This can be especially difficult

for people who are not able to easily walk to a different flight\'s waiting area. One of the ways

that an airline can make the transition easier is to provide a wheel chair and an escort to those

people who ask for help. It is generally known well in advance which passengers require help,

but it is not uncommon to receive notice when a passenger first registers at the airport. In rare

instances an airline may not receive notice from a passenger until just prior to landing.

Airlines are under constant pressure to keep their costs down. Wheel chairs wear out and are

expensive and require maintenance. There is also a cost for making the escorts available.

Moreover, wheel chairs and their escorts must be constantly moved around the airport so that

they are available to people when their flight lands. In some large airports the time required to move across the airport is nontrivial. The wheel chairs must be stored somewhere, but space is

expensive and severely limited in an airport terminal. Also, wheel chairs left in high traffic areas

represent a liability risk as people try to move around them. Finally, one of the biggest costs is

the cost of holding a plane if someone must wait for an escort and becomes late for their flight.

The latter cost is especially troubling because it can affect the airline\'s average flight delay

which can lead to fewer ticket sales as potential customers may choose to avoid an airline.

Epsilon Airlines has decided to ask a third party to help them obtain a detailed analysis of the

issues and costs of keeping and maintaining wheel chairs and escorts available for passengers.

The airline needs to find a way to schedule the movement of wheel chairs throughout each day

in a cost effective way. They also need to find and define the costs for budget planning in both

the short and long term.

Epsilon Airlines has asked your consultant group to put together a bid to help them solve their

problem. Your bid should include an overview and analysis of the situation to help them decide

if you fully understand their problem. They require a detailed description of an algorithm that

you would like to implement which can determine where the escorts and wheel chairs should be

and how they should move throughout each day. The goal is to keep the total costs as low as

possible. Your bid is one of many that the airline will consider. You must make a strong case as

to why your solution is the best and show that it will be able to handle a wide range of airports

under a variety of circumstances.

Your bid should also include examples of how the algorithm would work for a large (at least 4

concourses), a medium (at least two concourses), and a small airport (one concourse) under

high and low traffic loads. You should determine all potential costs and balance their respective

weights. Finally, as populations begin to include a higher percentage of older people who have

more time to travel but may require more aid, your report should include projections of

potential costs and needs in the future with recommendations to meet future needs.

2005 MCM Problems

PROBLEM A: Flood Planning

Lake Murray in central South Carolina is formed by a large earthen dam, which

was completed in 1930 for power production. Model the flooding downstream

in the event there is a catastrophic earthquake that breaches the dam.

Two particular questions:

Rawls Creek is a year-round stream that flows into the Saluda River a short

distance downriver from the dam. How much flooding will occur in Rawls Creek

from a dam failure, and how far back will it extend? Could the flood be so massive downstream that water would reach up to the

S.C. State Capitol Building, which is on a hill overlooking the Congaree River?

PROBLEM B: Tollbooths

Heavily-traveled toll roads such as the Garden State Parkway , Interstate 95,

and so forth, are multi-lane divided highways that are interrupted at intervals

by toll plazas. Because collecting tolls is usually unpopular, it is desirable to

minimize motorist annoyance by limiting the amount of traffic disruption

caused by the toll plazas. Commonly, a much larger number of tollbooths is

provided than the number of travel lanes entering the toll plaza. Upon entering

the toll plaza, the flow of vehicles fans out to the larger number of tollbooths,

and when leaving the toll plaza, the flow of vehicles is required to squeeze back

down to a number of travel lanes equal to the number of travel lanes before the

toll plaza. Consequently, when traffic is heavy, congestion increases upon

departure from the toll plaza. When traffic is very heavy, congestion also builds

at the entry to the toll plaza because of the time required for each vehicle to

pay the toll.

Make a model to help you determine the optimal number of tollbooths to deploy

in a barrier-toll plaza. Explicitly consider the scenario where there is exactly one

tollbooth per incoming travel lane. Under what conditions is this more or less

effective than the current practice? Note that the definition of \"optimal\" is up

to you to determine.

以上是2005年——2014年美国大学生数学建模竞赛试题

更多试题详见/undergraduate/contests/matrix/


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