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尽管珍爱网单一的盈利模式曾遭受质疑,但随着时间的推移,珍爱网现在已经拥有注册会员2600万人,平均每天新增4万名注册会员。由于会费收入足以满足公司成长的需要,因此珍爱网并不需要通过在页面上放置第三方广告等方式来增加收入来源。这样一来,会员就拥有了一个不受干扰的服务平台 相似文献
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他建立了成都现代艺术馆:他从2001年开始连续三届举办成都双年展;他还将成立成都文化艺术基金会,打造一个世界水准的成都歌剧院…… 相似文献
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利用代数数论的方法,证明了不定方程x2+256=y(3其中n∈N,x≡1(mod2),x,y∈Z)无整数解。 相似文献
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徐和谊的野心是让北汽在2010年进入世界500强。而在成功牵手北汽控股后,曹克波说",我们的目标是从成功走向更大的成功。" 相似文献
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Prof. Dr. H. Schneeberger 《Metrika》1981,28(1):179-189
Summary
Dalenius/Gurney [1951] published necessary conditions for the stratum boundaries, so that with Neyman's optimal allocation of the sample sizen the variance of the sample mean will become a minimum. They introduced in the variance of the sample mean for the sample sizesn
h
the opti mal values according to Neyman and differentiated this variance with respect to the stratum boundaries. Because Neyman's allocation formula yields only feasible solutions forn
h
N
h
, the conditions ofDalenius result in wrong, i.e. nonfeasible solutions, if one of the restrictionsn
h
N
h
(h=1 (1) L) is violated.By the example of a logarithmic normal distribution with =0, =1,5 forL=2 the behaviour of the Dalenius-Neyman-minimum and that of the feasible minimum will be shown in dependence on the sampling fractionq=n/N and a critical valueq
c
will be given. For valuesq>q
c
the Dalenius-Neyman-minimum is no longer feasible.For the same logarithmic normal distribution andL=2 (1) 10 this critical sampling fractionq
c
will be given (section 5).For different values of andq the optimal stratum boundaries and sampling fractions are listed in section 6 forL=2;3;4. 相似文献
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It is known that thes-meanm
s of a probability measure converge fors 1 to a medianm
1 called the natural median. For purposes of estimation it is important to know whetherm
s is not only continuous but also differentiable ats=1. We show that the functionsm
s is indeed differentiable ats=1 for the case of a unique as well as a non unique median. We also give an explicit formula for the derivative ats=1. 相似文献
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每年拿出主业的部分盈利通过专业机构去投资,以产业股权投资为方向,投资参股中国成长型企业,促使其上市从而分享其带来的高收益,不失为一种好的发展模式,可以有效规避企业直接多元化投资发展带来的风险 相似文献
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We examine the effect of Proposition
on revenues and housing prices in Massachusetts. Communities that were initially constrained by the law saw large increases in state aid and the use of fees. We use these initial constraints as instruments for changes in other components of revenue while treating the change in the property tax as exogenously determined by Proposition
. Our results strongly suggest that communities that were able to increase their property taxes more rapidly saw greater increases in their housing values in the period following passage of the law. 相似文献
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This paper establishes that the profit-seeking activities of private intermediaries can ensure Pareto efficiency in the standard pure-exchange monetary overlapping generations economy without the need for government monetary or fiscal policy intervention. Moreover, these profit-seeking activities are shown to rule out all aperiodic and k-periodic cycles for k greater than 2. Contrary to much recent work on intermediation, the profit opportunities that arise for intermediaries in this context are not due to assumed frictions or asymmetric information. Rather, they are due to the dynamic open-ended structure of the economy, which permits debt roll-over. 相似文献
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从中职计算机专业的现状出发,为了培养出适应社会需求的实用型技术人才,实现中职学校的计算机教育事业又好又快发展,文章阐述了计算机专业分方向教学的设想,提出了"1+1+1"的教学改革模式. 相似文献
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