Dynamic reliability models with conditional proportional hazards

A dynamic approach to the stochastic modelling of reliability systems is further explored. This modelling approach is particularly appropriate for load-sharing, software reliability, and multivariate failure-time models, where component failure characteristics are affected by their degree of use, amount of load, or extent of stresses experienced. This approach incorporates the intuitive notion that when a set of components in a coherent system fail at a certain time, there is a jump from one structure function to another which governs the residual lifetimes of the remaining functioning components, and since the component lifetimes are intrinsically affected by the structure function which they constitute, then at such a failure time there should also be a jump in the stochastic structure of the lifetimes of the remaining components. For such dynamically-modelled systems, the stochastic characteristics of their jump times are studied. These properties of the jump times allow us to obtain the properties of the lifetime of the system. In particular, for a Markov dynamic model, specific expressions for the exact distribution functions of the jump times are obtained for a general coherent system, a parallel system, and a series-parallel system. We derive a new family of distribution functions which describes the distributions of the jump times for a dynamically-modelled system.     

卫星光通信中平台抖动补偿技术研究

以卫星光通信系统为例,对空间光通信系统中光学平台的抖动进行了分析。研究了一种自调节前馈补偿技术,通过自适应信号处理或对前馈控制器进行直接优化,可对光学平台的抖动进行有效抑制。     

空间光通信ATP技术及其进展

对自由空间激光通信光束自动捕获、跟踪、瞄准（ＡＴＰ）系统的结构与系统主要技术指标进行了分析和讨论。通过对其中典型系统的介绍,进一步描述了ＡＴＰ技术的最新进展,论证了空间激光通信的可行性。     

Self‐Construal,Career Decision Self‐Efficacy,and Perceived Barriers Predict Mexican American Women's Life Satisfaction

This study used the social cognitive theory of well‐being (SCTW; Lent, 2004 ) to examine the role of career decision self‐efficacy (CDSE), perceived educational barriers, and independent self‐construal on the life satisfaction of 176 Mexican American college women. A 3‐step hierarchical regression analysis indicated that independent self‐construal, CDSE, and fewer perceived educational barriers significantly predicted greater life satisfaction among Mexican American college women above and beyond the influence of socioeconomic status and generational status. These findings are consistent with SCTW and highlight the need for counselors and researchers to be aware of the role that self‐construal, CDSE, and perceived educational barriers can have on Mexican American women's life satisfaction. Implications for practice at the secondary‐school and university levels are discussed.     

Utilization of Mixed Distributions in the Calculation of Polarization: The Case of Spain

Social Indicators Research - This study analyzes the evolution of salary polarization in the Spanish labor market. The paper proposes the use of mixed distributions to examine the consequences of...     

Social Entrepreneur: Same or Different from the Rest?

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - A social business responds to social problems usually ignored by institutions, mobilizing resources and generating...     

The Culture of High-Risk Alcohol Use Among Club and Intramural Athletes

Abstract

Objective: The purpose of this study was to examine the drinking patterns of club and intramural college athletes and compare their alcohol consumption, perceived norms around the excessive use of alcohol, experience of negative consequences, and employment of protective strategies with those of campus varsity athletes. Participants: A total of 442 undergraduate students attending a private, suburban institution in the Northeast participated in the American College Health Association National College Health Assessment-II Web survey in spring 2011. Thirty-five students identified themselves as varsity athletes, 76 identified as club sport athletes, and 196 students identified themselves as intramural athletes. Methods: Survey responses were analyzed using Statistical Package for the Social Sciences. The Pearson's correlation coefficient and test for independence were applied to identify significant relationships between athlete status and identified variables related to alcohol use. Results: Results indicated that there were significant correlations between athlete status and all variables, to varying degrees. Conclusions: These findings have implications for campus health promotion professionals and athletics program coordinators seeking to address high-risk alcohol use among college athletes.     

The Eating Disorders NOS Diagnostic Profile Among College Women

Abstract

The authors examined a proposed profile of eating-related behaviors, associated features, developmental issues, and help-seeking behavior among college women, using an eating disorder response program. The most common symptom scenario was a pattern of regular binge eating, together with daily exercise and occasional purging. The most common associated features were distressing or dysfunctional overconcern about body image and self-esteem, usually with day-to-day stress and intermittent depression. The women who fit this pattern also presented developmental issues of perfectionism, conflictual relationships with parents, and struggles for independence; and they tended to be ambivalent about seeking services. Implications for practice, including the need to develop a framework for eating disorder responses on campus that includes preventive programs and developmental interventions to target emerging and moderate concerns are discussed; limitations and the preliminary nature of the findings are explicated.     

Assessing the relevance of higher education courses

The establishment of the European Higher Education Area has involved specifying lists of professional competencies that programs are expected to develop, and with this the need for procedures to measure how every course within a higher education program is aligned with the program's competencies. We propose an instrument for characterizing this alignment, a process that we call assessing the relevance of a course. Using information from the course syllabus (objectives, contents and assessment scheme), our instrument produces indicators for characterizing the syllabus in terms of a competence list and for assessing its coherence. Because assessment involves quality, the results obtained can also be used to revise and improve the course syllabus. We illustrate this process with an example of a methods course from a mathematics teacher education program at a Spanish university.