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我快乐所以我博客--一品佳茗

每个人的心灵历程都是一首歌,我唱出我的所以我快乐。

 
 
 

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爱好广泛,一事无成,平生喜欢很多,至爱较少。喜欢书法,欧颜柳赵,也曾临过,但缺乏坚持,喜欢绘画,国画工写,西画彩描,也曾摹过,但缺乏深入,喜欢诗歌,诗词歌赋,也曾填过,但缺乏含蓄,喜欢舞蹈,单双多人,也曾迷过,但缺乏精巧,喜欢武术,刀枪棍棒,也曾练过,但缺乏功力,喜欢棋艺,军象跳围,也曾恋过,但缺乏心计,喜欢音乐,吹拉弹唱,也曾试过,但缺乏细胞。 不喜欢数学却上了贼船,不想当教师最终却以之为生。干一件事时间久了,可能会厌倦,也可能会喜欢。兴趣是靠自己培养的。若一个人愿意学习,相信久了会取得成绩。

网易考拉推荐

2011PROBLEM A: Snowboard Course  

2013-12-01 16:01:15|  分类: 默认分类 |  标签: |举报 |字号 订阅

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A题: 滑雪场问题 确定一个滑雪场(现在仅知是半管状)的形状来使得一个滑板运动员所能达到的垂直间距最大化。 垂直间距是指,距半管状的的边缘间的最大垂直距离。 修改形状以适应其他要求,例如使得运动员的扭转最大化。 要建造一个实用的场地,又该做出何种取舍?

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.

ICM PROBLEM

PROBLEM C: How environmentally and economically sound are electric vehicles? Is their widespread use feasible and practical?

Click the title below to download a PDF of the 2011 ICM Problem.

Your ICM submission should consist of a 1 page Summary Sheet and a 20 page solution for a total of 21 pages.

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