电力系统同步网的建设与思考

数字同步网已经成为了通信网营运的重要支柱之一。针对电力系统通信业务面向市场开放的需求 ,阐述了建设电力系统同步网的重要性 ;研究和分析了同步网中时钟配置、链路选择和同步方式、网络管理等技术问题 ,并对电力系统中同步网的发展提出了一些建议。     

Race and Population Change: A Longitudinal Look at Cleveland Neighborhoods

This paper investigates the relationship of racial composition to neighborhood population change from 1910 to 1990 in the Cleveland metropolitan area. To better understand the long-term dynamics of urban neighborhood change, we focus our analysis upon the longitudinal relationship of race, socioeconomic status, and life cycle stage to changes in neighborhood population densities. First, we find that the more established neighborhoods of the African-American community have experienced dramatic declines in population since 1950, a pattern that represents a clear change from the earlier part of the twentieth century. Second, population loss is experienced through a variety of mechanisms, including the demolition of dwellings, the increase in housing vacancy, and the decline of household size. Third, much of this population loss should be interpreted within the context of high economic distress, occurring most frequently in older African-American communities. Over time, economic distress appears to be more important than race in and of itself in leading to the loss of neighborhood populations.     

The transition to parenthood in Puerto Rico: Occupational status and the timing of first births

This study examines the relationship between occupational status and fertility timing during a period of rapid development in Puerto Rico. Our fundamental hypothesis is that women with higher status occupations face greater opportunity costs than those with less valued jobs and therefore will be more likely to postpone parenthood until later ages than women without such high costs. We test this hypothesis using event history techniques with data from the 1982 Puerto Rico Fertility and Family Planning Assessment, an island-wide survey of women between the ages of 15 and 49. The analysis examines the effects of occupational status on the timing of first births, and finds strong support for the basic hypothesis, especially regarding the post-ponement of teen births. After the teen years, the effects are less pronounced. Overall, it appears that employment opportunities have played an important role in childbearing decisions in Puerto Rico.An earlier version of this paper was presented at the annual meeting of the Population Association of America, Denver, Colorado, 30 April–2 May 1992.     

Pre-term Foetal Life Times in Scotland

A proportional hazards model was used to evaluate the association between ten categorical covariates and the risk of pre-term delivery for women having their first child and women in subsequent pregnancies. An adaptation of the model for use with grouped survival times made it possible to model foetal life times between 28 and 36 completed weeks of gestation for 67,000 Scottish singleton births in 1981. The use of the model was justified by testing time-dependent effects. For both groups of women age, and a history of abortion, were major factors associated with increased hazard. For women experiencing a second or higher-order birth a history of perinatal death was also associated with substantially increased hazard to the pregnancy.     

如何解释资本结构的调整方式和速度--基于福耀玻璃的案例分析与讨论

以现有资本结构理论为基础,试图寻找能解释各种典型公司资本结构调整方式和速度的理论框架。首先以案例分析为基础分析了主流资本结构理论对案例公司资本结构调整方式的解释程度和解释异同。然后结合公司的财务政策,定性分析了主流理论对于资本结构调整方式存在解释异同的背后原因以及将主流理论融合的理论框架。认为从资金供需的角度理解权衡理论和优序融资理论以及市场择时理论,可以将这些主流理论统一起来解释各种典型的资本结构调整方式。同时,发现以计量模型估算的资本结构调整速度推断资本结构调整到目标水平所需的时间,会误导人们对于资本结构调整方式的理解。     

论融资约束下企业最优投资时机选择

利用企业投资的三期静态模型,考察了企业投资额、自有资金与外部融资之间的关系。通过比较企业在不同期间即时投资和延迟投资的投资收益,求解得到企业在融资约束下的投资临界值,进而得出了企业在投资可延迟条件下的最优投资时机和投资规则。     

合并高校电子阅览室开放式管理系统的开发与应用

文章简要介绍了合并高校图书馆电子阅览室管理系统的设计原理、流程及方法,实现了对多校区电子阅览室集中管理,不仅方便读者上机,计费准确,同时减轻了管理人员劳动强度,提高管理层次.     

Optimal timing of investments in advanced manufacturing systems under competition

Large initial investment in advanced manufacturing systems (AMS) makes it imperative to develop economic justification methods. Once the new system has been properly justified, a critical issue facing the firm is the optimal timing of the installation in an industry. In this paper we use a game-theoretic model by which the optimal timing of the investments in AMSs is analysed. The existence of timing equilibria is demonstrated and simple decision rules of optimal strategy are provided. Economic interpretations of the decision rules are subsequently made clear. Finally, illustrative examples are used to demonstrate the correctness and usefulness of the analysis.     

Religion,social milieu,and the contraceptive revolution

This study examines how the social environment of religious congregations affects the spread of contraceptive use in developing contexts, using Mozambique as a case study. Analysis of qualitative data collected in urban areas of that country in 1998-99 and of the data from the 1997 Mozambique Demographic and Health Survey suggests that, in urban areas, the environment of more socioculturally diverse and inclusive Roman Catholic and mission-based Protestant congregations is more propitious to the spread and legitimization of modern contraception than the milieu of smaller, relatively homogeneous, independent churches. In rural areas, however, sociocultural diversity within and across different religious denominations is minimal, and membership in any formal congregation offers an advantage in contraceptive learning.     

论中国古代的司法时令制度

“刑以秋冬”的司法时令思想有确切文字记载的是春秋时期,但这一思想的起源还应早于此。自汉代起,“刑以秋冬”的思想逐渐发展成我国古代的一项司法制度,并最终在唐代得到完善。在发展的过程中,轻罪与时令的关系逐渐断绝,而关于死刑行刑的规定却越来越详细。司法时令制度的哲学基础是“天人合一”、“天人相关”的思想,其现实基础是以农业为主的经济状况。