&106.Between&1980&and&2000&the&sea&otter&population&of&the&Aleutian&Islands&declined&precipitously.
There&were&no&signs&of&disease&or&malnutrition,so&there&was&probably&an&increase&in&the&number&of&otters&
being&eaten&by&predators.Orcas&will&eat&otters&when&seals,their&normal&prey,are&unavailable,and&the&
Aleutian&Island&seal&population&declined&dramatically&in&the&1980s.Therefore,orcas&were&most&likely&the&
immediate&cause&of&the&otter&population&decline.
Which&of&the&following,if&true,most&strengthens&the&argument?
A.The&population&of&sea&urchins,the&main&food&of&sea&otters,has&increased&since&the&sea&otter&population&
B.Seals&do&not&eat&sea&otters,nor&do&they&compete&with&sea&otters&for&food,
C.Most&of&the&surviving&sea&otters&live&in&a&bay&that&is&inaccessible&to&orcas.
D.The&population&of&orcas&in&the&Aleutian&Islands&has&declined&since&the&1980s
E.An&increase&in&commercial&fishing&near&the&Aleutian&Islands&in&the&1980s&caused&a&slight&decline&in&the&
population&of&the&fish&that&seals&use&for&food.
解析内容：
GMAT复习热点
GMAT培训热点CR-OG18-文本逻辑：第166-185题 练习册详情
CR-OG18-文本逻辑：第166-185题
题目数量：20题
建议练习时间：
练习人数：1011人
平均正确率：66%
练习进度：
练习册题目信息
Those who receive preventive care are not more likely to need urgent care than are those who do not receive preventive care.
Jay intends the phrase “economic gains” to refer only to gains accruing to institutions within the health care system.
Productive members of society are more likely than others to suffer preventable illnesses.
The economic contributions of those who receive preventive medical care may outweigh the economic losses caused by preventive care.
Jay is incorrect in stating that patients who receive preventive medical care are long-lived.
0人做过此题
平均耗时为0
平均正确率为
展开题目内容
Some boreal owls range over an area eight times larger than the area over which any other owl of similar size ranges.
Boreal owls range over larger areas in regions where food of the sort eaten by small mammals is sparse than they do in regions where such food is abundant.
After their young hatch, boreal owls must hunt more often than before in order to feed both themselves and their newly hatched young.
Sometimes individual boreal owls hunt near a single location for many weeks at a time and do not range farther than a few hundred yards.
The boreal owl requires less food, relative to its weight, than is required by members of other owl species.
6141人做过此题
平均耗时为2min4s
平均正确率为
展开题目内容
Physicians in the country where the outbreak occurred have become hesitant to prescribe antibiotics since they are frequently in short supply.
People in the country where the outbreak occurred often consume foods produced from animals that eat antibiotics-laden livestock feed.
Use of antibiotics in two countries that neighbor the country where the outbreak occurred has risen over the past decade.
Drug-resistant strains of salmonella have not been found in countries in which antibiotics are not generally available.
Salmonella has been shown to spread easily along the distribution chains of certain vegetables, such as raw tomatoes.
0人做过此题
平均耗时为0
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展开题目内容
The first provides evidence in support of the overall position that t the second is evidence that has been used to support an opposing position
The first provides evidence in support of the overall position that t the second is that position
The first provides evidence in support of an intermediate conclusion that is drawn to provide support for the overall position that t the second provides evidence against that intermediate conclusion
The first is evidence that has been used to support a conclusion that the
the second is evidence offered in support of the historian’s own position
The first is evidence that has been used to support a conclusion that the
the second is further information that substantiates that evidence.
10000人做过此题
平均耗时为5min18s
平均正确率为
展开题目内容
There are surface features of every Damascus blade—including the blades produced by the contemporary sword maker—that are unique to that blade.
The iron with which the contemporary sword maker made Damascus blades came from a source of iron that was unknown two centuries ago.
Almost all the tools used by the contemporary sword maker were updated versions of tools that were used by sword makers over two centuries ago.
Production of Damascus blades by sword makers of the past ceased abruptly after those sword makers’ original source of iron became exhausted.
Although Damascus blades were renowned for maintaining a sharp edge, the blade made by the contemporary sword maker suggests that they may have maintained their edge less well than blades made using what is now the standard process for making blades.
0人做过此题
平均耗时为0
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An orbiting space telescope due to be launched this year is far behind schedule and over budget, whereas the largest ground-based telescope was both within budget and on schedule.
Ground-based telescopes located on mountain summits are not subject to the kinds of atmospheric distortion which, at low altitudes, make stars appear to twinkle.
By careful choice of observatory location, it is possible for large-aperture telescopes to avoid most of the kind of wind turbulence that can distort image quality.
When large-aperture telescopes are located at high altitudes near the equator, they permit the best Earth-based observations of the center of the Milky Way Galaxy, a prime target of astronomical research.
Detailed spectral analyses, upon which astronomers rely for determining the chemical composition and evolutionary history of stars, require telescopes with more light-gathering capacity than space telescopes can provide.
0人做过此题
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serious scientific research is not a solitary activity, but relies on active cooperation among a group of colleagues
research scientists tend not to regard as colleagues those scientists whose renown they envy
a scientist can become a famous popularizer without having completed any important research
research scientists believe that those who are well known as popularizers of.science are not motivated to do important new research
no important new research can be accessible to or accurately assessed by those who are not themselves scientists
9976人做过此题
平均耗时为8min43s
平均正确率为
展开题目内容
If Stonebridge does not raise taxes on its residents to maintain its infrastructure, the city will become much less attractive to live in as that infrastructure decays.
Stonebridge at present benefits from grants provided by the national government to help maintain certain parts of its infrastructure.
If there is a small increase in property taxes in Stonebridge and a slightly larger proportion of total revenue than at present is allocated to infrastructure maintenance, the funding will be adequate for that purpose.
Demographers project that the population of a region that includes Stonebridge will start to increase substantially within the next several years.
The property taxes in Stonebridge are significantly lower than those in many larger cities.
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the price of oil is expected to remain relatively stable over the next several years
the improvement in the economic situation in Utrania is expected to result in a dramatic increase in the proportion of Utranians who own automobiles
most of the investment in new oil fields in Utrania is expected to come from foreign sources
new technology is available to recover oil from old oil fields formerly regarded as depleted
many of the new oil fields in Utrania are likely to be as productive as those that were developed during the period when Utrania was a major oil exporter
8730人做过此题
平均耗时为6min37s
平均正确率为
展开题目内容
Other major pork marketers will probably stop buying pork raised on feed containing growth-promoting antibiotics if Smee no longer buys such pork.
The decline in hog growth due to discontinuation of antibiotics can be offset by improved hygiene.
Authorities are promoting the use of antibiotics to which microorganisms have not yet developed resistance.
A phaseout of use of antibiotics for hogs in one country reduced usage by over 50 percent over five years.
If Smee stops buying pork raised with antibiotics, the firm’s costs will probably increase.
0人做过此题
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None of the volunteers in the second half believed that the unusual experiences they reported were supernatural.
All of the volunteers in the first half believed that the researchers’ statement that the theater was haunted was a lie.
Before being told about the theater, the volunteers within each group varied considerably in their prior beliefs about supernatural experiences.
Each unusual experience reported by the volunteers had a cause that did not involve the supernatural.
The researchers did not believe that the theater was haunted.
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In Jalica, domestically produced oil is more expensive than imported oil.
The Jalican government did not intend the new fuel-efficiency requirement to be a pollution-reduction measure.
Some pollution-control devices mandated in Jalica make cars less fuel-efficient than they would be without those devices.
The new regulation requires no change in the chemical formulation of fuel for cars in Jalica.
Jalicans who get cars that are more fuel-efficient tend to do more driving than before.
0人做过此题
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Whether corn could be bioengineered to produce the insecticide
Whether plantings of cotton that does not produce the insecticide are suffering unusually extensive damage from bollworms this year
Whether other crops that have been bioengineered to produce their own insecticide successfully resist the pests against which the insecticide was to protect them
Whether plantings of bioengineered cotton are frequently damaged by insect pests other than bollworms
Whether there are insecticides that can be used against bollworms that have developed resistance to the insecticide produced by the bioengineered cotton
5891人做过此题
平均耗时为3min8s
平均正确率为
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Other kinds of rare lightning also occur with unusually high frequency in the vicinity of forest fires.
The positive-charge strikes that occur near forest fires tend to be no more powerful than positive strikes normally are.
A positive-charge strike is as likely to start a forest fire as a negative-charge strike is.
Thunderstorms that occur in drifting clouds of smoke have extra positive-charge strikes weeks after the charge of the smoke particles has dissipated.
The total number of lightning strikes during a thunderstorm is usually within the normal range in the vicinity of a forest fire.
0人做过此题
平均耗时为0
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The nursery sells more than ten different varieties of clematis.
The largest clematis nursery in North America sells nothing but clematis plants.
Some of the jackmanii sold by the nursery are sold to gardeners outside North America.
Most North American gardeners grow clematis in their gardens.
For all nurseries in North America that specialize in clematis, at least ten percent of the clematis plants they sell are jackmanii.
0人做过此题
平均耗时为0
平均正确率为
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Resistance to several other commonly prescribed antibiotics has not increased since 1990 in Aqadestan.
A large number of Aqadestanis never seek medical help when they have a sinus infection.
When it first became available, perxicillin was much more effective in treating bacterial sinus infections than any other antibiotic used for such infections at the time.
Many patients who take perxicillin experience severe side effects within the first few days of their prescribed regimen.
Aqadestani health clinics provide antibiotics to their patients at cost.
0人做过此题
平均耗时为0
平均正确率为
展开题目内容
It fails to adequately address the possibility that many of the volunteers may not have understood what the psychological questionnaire was designed to measure.
It takes for granted that the volunteers with the highest levels of self-esteem had better social skills than did the other volunteers, even before the former volunteers had attained their high levels of self-esteem.
It overlooks the possibility that people with very high levels of self-esteem may tend to have a less accurate perception of the strength of their own social skills than do people with moderate levels of self-esteem.
It relies on evidence from a group of volunteers that is too small to provide any support for any inferences regarding people in general.
It overlooks the possibility that factors other than level of self-esteem may be of much greater importance in determining the strength of one’s social skills.
0人做过此题
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The first is the position th the second presents grounds for rejecting an alternative position.
The first is the position th the second is an alternative position that the argument rejects.
The first presents a strategy for achi the second presents a drawback to that strategy.
The first presents a strategy for achi the second presents grounds for preferring a different goal.
The first presents a strategy that, according to the argument, the second presents a way of improving the effectiveness of that strategy.
109人做过此题
平均耗时为1min52s
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The total acreage devoted to grain production in Gortland will soon decrease.
Importing either grain or meat will not result in a significantly higher percentage of Gortlanders' incomes being spent on food than is currently the case.
The per capita consumption of meat in Gortland is increasing at roughly the same rate across all income levels.
The per capita income of meat producers in Gortland is rising faster than the per capita income of grain producers.
People in Gortland who increase their consumption of meat will not radically decrease their consumption of grain.
9276人做过此题
平均耗时为5min43s
平均正确率为
展开题目内容
The unemployment rate in the city is higher today than it was when Mayor Delmont took office.
The average pay for jobs in the city was at a ten-year low when Mayor Delmont took office.
Each year during Mayor Delmont's tenure, the average pay for jobs that were eliminated has been higher than the average pay for jobs citywide.
Most of the jobs eliminated during Mayor Delmont's tenure were in declining industries.
The average pay for jobs in the city is currently lower than it is for jobs in the suburbs surrounding the city.
10000人做过此题
平均耗时为3min41s
平均正确率为
展开题目内容&21,&Many&agriculturally&intensive&area&ofthe&world&are&beginning&to&encounter&water&scarcity&problems.&
As&a&result,&manyfarmers&in&these&areas&are&likely&to&reduce&their&output&as&the&water&supplythey&need&in&
order&to&maintain&production&shrinks.&However,&one&group&offarmers&in&such&a&region&plans&to&increase&
their&production&by&implementing&techniquesfor&water&conservation.
Which&of&the&following,&if&true,&would&moststrongly&support&the&prediction&that&the&group&s&plan&will&
(A)&Farmers&who&can&gain&a&large&share&ofthe&market&in&their&region&will&be&better&positioned&to&control&
more&waterresources.
(B)&Most&agricultural&practices&in&areawith&water&shortages&are&water-&intensive.
(C)&Other&regions&of&the&world&not&facingwater&shortage&are&likely&to&make&up&for&the&reduction&in&
agricultural&output.
(D)&Demand&for&agricultural&products&in&thegroup&s&region&is&not&expected&to&decline.
(E)&More&than&half&the&water&used&foragricultural&in&the&farmers&&region&is&lost&to&evaporation&or&leakage&
fromirrigation&channels.
解析内容：
GMAT复习热点
GMAT培训热点您所在位置： &
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聚类算法及在图像分割中的应用和研究.pdf 71页
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聚类分析技术作为一种数据处理手段近些年来一直是人们的研
究热点，其在模式识别、数据挖掘、图像处理等领域内有着广泛的应
用。聚类算法主要分为基于划分的聚类算法和基于层次的聚类算法，
其中基于划分的聚类算法是模式识别和图像分割中最常用的算法类
型，C．均值和模糊C均值聚类算法作为两种经典的划分聚类算法在应
用中也最为广泛。
本文首先介绍了聚类的数据类型和聚类算法的分类，然后对几种
常用的划分聚类算法进行了分析，得出其与奥卡姆剃刀准则存在着天
然的内在联系。本文还分析了文献中常用的几种聚类有效性指标，并
Cut算法在图像分
研究了C．均值算法、模糊C．均值算法、No珊alized
割中的应用，通过实验对这些算法进行了对比分析。
全文共分六章，各章的主要内容如下：
第一章介绍聚类的概念、应用、处理的数据类型以及聚类方法的
分类情况，并确定本文的研究范围和基本框架。
第二章对基于划分的聚类算法进行了简要的评述，同时分析了一
些常用的聚类算法如G均值，模糊c．均值等和奥卡姆剃刀准则的关
第三章则主要针对国内外当前对聚类有效性的研究做深入全厩
的介绍和分析。在对这些聚类有效性指标进行分类、介绍和分析之后，
指出了在设计聚类指标时需要注意的问题。
第四章介绍了图像处理方面的基础知识以及图像分割的基础知
识，同时也简要说明了聚类在图像分割中的应用情况。
第五章将两种流行的聚类方法c．均值和模糊C一均值算法应用到
在图像分割中，并分析比较了实验的结果。本章还详细介绍了一种较
新的图像分割方法No瑚alizedCut算法，经过编程实验，将此算法分
别应用到了实数据集合和图像数据中，都得到了较好的效果。
北京交通大学硕士学位论文
第六章结束语总结了全文，并对聚类算法、聚类有效性函数及其
在图像分割的应用中还存在的问题进行了讨论。
关键词：聚类分析，聚类有效性，奥卡姆剃刀，图像分割，No珊alized
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正在加载中，请稍后...焊丝H08CrMoC、H08CrMoE、H08CrMoG后面的C、E、G是什么意思_百度知道
焊丝H08CrMoC、H08CrMoE、H08CrMoG后面的C、E、G是什么意思
焊丝牌号合金元素后面的字母如A、C、E、G等表示焊丝中的硫、磷、砷等杂质的含量级别(一般是指硫和磷)。如A级：S ≤0.030%
C级：S ≤0.008%
E级：S ≤0.025%
G级：S ≤0.006%
采纳率：71%
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