Estimation of parameters of a right truncated exponential distribution

The maximum likelihood, moment and mixture of the estimators are for samples from the right truncated exponential distribution. The estimators are compared empirically when all the parameters are unknown; their bias and mean square error are investigated with the help of numerical technique. We have shown that these estimators are asymptotically unbiased. At the end, we conclude that mixture estimators are better than the maximum likelihood and moment estimators.     

A family of distributions to model load sharing systems

The main characteristic of a load sharing system is that after the failure of one component the surviving components have to shoulder extra load and hence are prone to failure at an earlier time than what is expected under the original model. In others, the failure of one component may release extra resources to the survivors, thus delaying the system failure. In this paper we consider such m component systems and some observation schemes and identifiability issues under them. Then we construct a general semiparametric multivariate family of distributions which explicitly models this phenomenon through proportional conditional hazards. We suggest estimates for the constant of proportionality. We propose a nonparametric test for the hypothesis that the failures take place independently according to the common distribution against the alternative hypothesis that the second failure takes place earlier than warranted, study its properties and illustrate its use.     

基于局域网的信息系统安全监控体系研究

针对某局域网的教务管理信息系统的安全性进行了全面的分析,提出了该系统所需采用的安全策略和方法,设计了系统权限分配和用户认证、记录追踪、数据库连接的通讯协议、启用C2级审核、警报系统等程序,实现了SLTMIS完整有效的安全监控体系.     

Expanding the HRD Role: Improving employee well-being and organizational performance

Abstract

An important opportunity for the HRD profession lies in assessing and reshaping the psychosocial work environment to create a healthy, mentally focused workforce that provides their organization with a competitive advantage. We explain why HRD professionals should be concerned with employee well-being, offer suggestions for assessing the work environment through a stress audit and discuss four key work factors that affect well-being: job control, role overload, social support and supervisor behaviour. By expanding their role to these concerns, HRD professionals can improve quality of life and contribute to organizational effectiveness. If they do, the result should be healthier employees, healthier organizations and a greater recognition of HRD's potential for transforming organizations.     

Outsourcing and Performance in Entrepreneurial Firms: Contingent Relationships with Entrepreneurial Configurations*

This article develops and examines an empirical typology of entrepreneurial firms, based on organizational and life cycle characteristics. Results indicate five entrepreneurial configurations representing the essential contingent features of age, size, innovation, and governance structure (Elders, Giants, Innovators, and Owners) and one configuration representing a mix of all features (Balanced). We found that (i) outsourcing affected financial performance in entrepreneurial firms and (ii) configurations moderated this relationship. Results support the use of salient contingent features of age, size, innovation, and governance structure to predict outsourcing effectiveness in the entrepreneurial configurations. That is, entrepreneurial firms that aligned their configurational characteristics with outsourcing tended to have greater gains in financial performance. From a resource dependency perspective, managing these alignments has important implications for entrepreneurial firm performance.     

Macroeconomic determinants of migration: the case of Germany, 1964-1988

Macroeconomic determinants of immigration are analysed with pooled cross-country and time series data on net immigration to Germany from European countries during 1964-1988.
Results demonstrate clearly that both high and low frequency determinants have been important. Long run trends are determined by the degree and speed of per capita income convergence between the sending and receiving countries, while year-to-year changes in net immigration flows are dominated by cyclical economic conditions.     

Effect of Level of Disaggregation on Conjoint Cross Validations: Some Comparative Findings*

Early formulations of conjoint models focused on part-worth estimation at the individual level. As the methodology's popularity grew so did industry demands for increasingly larger numbers of attributes and levels. In response to these demands, new approaches, based on partial or full data aggregation (such as clusterwise/latent class conjoint and choice-based conjoint), have appeared. This paper suggests that pooled-data models will often be successful in predicting market shares when researchers employ monotonic attributes. In these cases more of a good attribute (or less of a bad attribute) is always more preferred. In the more realistic case, in which some of the attributes may be nonmonotonic, we find that data aggregation does not predict holdout sample preferences as well as individual part-worth models.