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排序方式: 共有267条查询结果,搜索用时 15 毫秒
1.
本文主要讨论自适应调制与编码系统(Adaptive Modulation and Coding system)的原理,介绍AMCS实现的几个关键技术,包括RCPT(速率适配凿孔turbo)码、高阶调制、H-ARQ和MIMO(多输入多输出)系统。介绍了在WCDMA的高速下行分组接入业务(HSDPA)中使用的自适应调制编码机制,并讨论了可能增加的设备复杂度。  相似文献   
2.
In the process of coding open-ended questions, the evaluation of interjudge reliability is a critical issue. In this paper, using real data, the behavior of three coefficients of reliability among coders, Cohen’s K, Krippendorff’s α and Perreault and Leigh’s I r are patterned, in terms of the number of judges involved and the categories of answer defined. The outcome underlines the importance of both variables in the valuations of interjudge reliability, as well as the higher adequacy of Perreault and Leigh’s I r and Krippendorff’s α for marketing and opinion research.  相似文献   
3.
我国现行税制中存在的重复征税问题   总被引:1,自引:0,他引:1  
我国现行税制的基本框架是通过1994年税制改革建立起来的,而1994年税制改革正是以1993年宏观经济紧缩政策为背景设计的,从制度设计上没有充分考虑重复征税对经济运行的影响。本文拟对当前我国税制中存在的重复征税问题进行分析,并提出免除重复征税的具体措施。  相似文献   
4.
数据流链接技术在军用维修物资编码系统中的应用   总被引:1,自引:0,他引:1  
游伟  刘建国 《物流科技》2007,30(1):61-63
本文从军用维修物资业务管理的角度,讲述了军用维修物资的分类体系;从军用维修物资信息管理的角度,讲述了军用维修物资的信息分类;从计算机数据处理的角度,讲述了数据流链接技术在军用维修物资编码系统中的应用,并给出了其应用程序流程.  相似文献   
5.
在对通用制造工艺进行调研的基础上,采用面分类法和线分类法相结合的方式对制造工艺进行分类,得到制造工艺分类标准草案,以及在此基础上对通用制造工艺进行编码,有效地解决了机械制造企业信息化过程中对通用制造工艺知识的交流与共享问题。  相似文献   
6.
This paper develops constant-quality price indices for three categories of real estate-apartment buildings, vacant land, and condominiums—for the city of Geneva, Switzerland. We use both the hedonic and repeat sales models to estimate the price level and, in turn, the rate of price change. The general pattern of each series suggests that real estate prices in Geneva were fairly stable throughout the 1970s, increased sharply during the 1980s, but gave back some of these gains in the early 1990s. Interestingly, the sharp rise in prices in the second half of the 1980s is very similar to that found in some regions of the United States. We also consider the problem, implicit in the repeat sales method, of revisions in previously estimated price indices as additional data become available in later years.  相似文献   
7.
There has been copious research work on the development of house price models and the construction of house price indices. However, results in some studies revealed that the accuracy of such indices could be subject to selection bias when using only information from a sample of sold properties to estimate value movements for the entire housing stock. In particular, estimated house price appreciation is usually systematically higher among properties that change hands more frequently. It therefore suggests that the determination of important factors affecting the transaction frequency or intensity of a housing unit should be a more fundamental research question. This paper examines the possible factors that determine the popularity of residential unit by means of a repeated sales pattern. The Poisson regression model and event history analysis techniques are employed to assess the effect of attributes on transaction frequency and intensity. The event history analyses technique can take account of transaction-specific as well as time-dependent covariates, and therefore is recommended for analyzing repeated sales data in a real estate market. All transaction records during the period 1993–2000 from the Land Registry of one of the most popular residential estates in Hong Kong were used to illustrate the method. Unlike a response to favorable transaction price, good quality units do not necessarily inherently display a high transaction frequency. Rather, units of average quality are more likely to be transactionally active.  相似文献   
8.
We develop an algorithm that forecasts cascading events, by employing a Green’s function scheme on the basis of the self-exciting point process model. This method is applied to open data of 10 types of crimes happened in Chicago. It shows a good prediction accuracy superior to or comparable to the standard methods which are the expectation–maximization method and prospective hotspot maps method. We find a cascade influence of the crimes that has a long-time, logarithmic tail; this result is consistent with an earlier study on burglaries. This long-tail feature cannot be reproduced by the other standard methods. In addition, a merit of the Green’s function method is the low computational cost in the case of high density of events and/or large amount of the training data.  相似文献   
9.
针对无线传感器中的节点调度传输问题,提出了一种基于网络编码的协同点对点信息交换算法。由于该算法不仅能够充分利用无线信道的广播特性,而且使用了协同点对点信息交换,从而有效地弥补了PIE算法在数据包的个数大于节点数目的情况下,性能不理想的缺陷,实现了传输次数的减少。仿真结果表明,所提算法的传输有效性明显地优于PIE算法和最少优先算法。  相似文献   
10.
Using data gained from ethnographic research and interviews, this article examines ‘third place’ sociability in the social interactions of the Polar Bears of Martha’s Vineyard, a group of predominantly but not exclusively middle-aged and senior African-American men and women who swim, exercise and socialise together each morning at ‘the Inkwell’ beach. Using Georg Simmel’s concept of sociability and Ray Oldenburg’s third-place theoretical framework, this study explores the key role of the Monday communal breakfast and the function of conversation in establishing bonds between individuals. It further investigates the promotion of strong feelings of social connectedness, belonging, social support, social capital gains and community among its group members. The ongoing sociability and informal rules of the Polar Bears of Martha’s Vineyard has enabled it to become a model group demonstration of third-place community building. The importance of race, class and place is socio-historically investigated within the broader social context of the popular racialised section of the beach, ‘the Inkwell’, of African-American community life, and within the sub-community milieu of group social interaction.  相似文献   
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