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【简答题】
Translate the following paragraphs into Chinese. Determining whether our known fossil sites shared a distinctive spectral signature was no small task, because for each site we had to assess the combination of values in six bands of the electromagnetic spectrum provided by the Landsat data. Our problem was essentially one of pattern recognition in multiple dimensions, something that humans do not do particularly well but that computers excel at. So we enlisted a socalled artificial neural network—a computational model capable of learning complex patterns. Our artificial neural network revealed that the basin’s known fossil sites do indeed share a spectral signature, and it was able to easily tell these sandstone localities apart from other types of ground cover, such as wetlands and sand dunes. But the model had its limitations. Neural networks, by their very nature, are analytical “black boxes”, meaning they can distinguish patterns, but they do not reveal the actual factors that allow different patterns to be distinguished. So whereas our neural network could easily and accurately distinguish fossil localities from wetlands or sand dunes, it couldnot tell us how the spectral signatures of different land covers actually differed in the six bands of the Landsat data—information that could conceivably help us conduct a more targeted search. Another limitation of the neural network approach is that it is based entirely on the analysis of individual pixels. The problem is that the area of an individual Landsat pixel, which measures 225 square meters, does not necessarily correspond to the size of a fossil locality: Some localities are larger than an individual pixel; some are smaller. Thus, the neural network’s predictions about the location and extent of potential fossil sites (or a certain type of ground cover, for that matter) do not always match up with reality.
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【单选题】对于一个集合 M ,若 ,则 m 属于 M 的隶属度为( )
A.
1
B.
0
C.
0.5
D.
( 0,1 )中某一数值
【单选题】下列哪种受体激动时可使唾液腺分泌
A.
N受体
B.
M受体
C.
α受体
D.
β受体
【单选题】以下哪一项不是天麻的成分()
A.
天麻素
B.
天麻甙元
C.
棕榈酸
D.
琥珀酸
【单选题】力 使一质点从点A(1,2,0)移到点B(3, 2,-1)作的功为
A.
1焦耳
B.
2焦耳
C.
5焦耳
D.
10焦耳
【单选题】近百年来,在达里湖地区,长期的干旱使多草的湿地大量萎缩,变成盐碱地。多草的湿地是鸭类、鹅类以及其他种类水鸟筑巢和孵化的场所。然而,随着湿地的不断萎缩,该地区赤麻鸭数量平均下降的速度却远低于天鹅数量平均下降的速度。如果以下哪项陈述为真,对上文中的不一致给出了最佳的解释?()
A.
赤麻鸭每窝孵化8至10枚卵,天鹅每窝孵化2至3枚卵,成活率大体相当。
B.
环境保护措施的加强减缓了赤麻鸭、天鹅及其他种类水鸟数量平均下降的速度。
C.
赤麻鸭和天鹅都是迁徙性鸟类,赤麻鸭在迁徙过程中更容易遭到捕杀。
D.
除湿地外,赤麻鸭逐渐学会在树洞和崖洞筑巢孵化,天鹅则未能如此。
【简答题】对高频晶体管结构上的基本要求是:()、()、()和()。
【判断题】教育现象是丰富、零散、多变的,因此不具备研究意义。
A.
正确
B.
错误
【单选题】力 使质点从点A(1,2,0)移到点B(3, 2,-1)作的功为( )
A.
1焦耳
B.
2焦耳
C.
5焦耳
D.
10焦耳
【简答题】设所有可表示为两整数的平方差的整数组成集合M.给出下列命题: ①所有奇数都属于M. ②若偶数2k属于M,则k∈M. ③若a∈M,b∈M,则ab∈M. ④把所有不属于M的从小到大依次排成一个数列,则它的前n项和S n ∈M. 其中正确命题的序号是______.(写出所有正确命题的序号)
【单选题】以下哪一项不是天麻的成分
A.
天麻素
B.
天麻苷元
C.
棕榈酸
D.
乙酰天麻素
E.
琥珀酸
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