Heterogeneous data modeling with two-component Weibull–Poisson distribution

The mixture distribution models are more useful than pure distributions in modeling of heterogeneous data sets. The aim of this paper is to propose mixture of Weibull–Poisson (WP) distributions to model heterogeneous data sets for the first time. So, a powerful alternative mixture distribution is created for modeling of the heterogeneous data sets. In the study, many features of the proposed mixture of WP distributions are examined. Also, the expectation maximization (EM) algorithm is used to determine the maximum-likelihood estimates of the parameters, and the simulation study is conducted for evaluating the performance of the proposed EM scheme. Applications for two real heterogeneous data sets are given to show the flexibility and potentiality of the new mixture distribution.     

An Exponential Model for Damage Accumulation

In this article, we present a general model for predicting the fatigue behavior for any stress level and amplitude using the exponential model. Based on the Wöhler field for fixed stress level, a compatibility functional equation enables us to derive the general model with eight parameters. The problem of parameter estimation is then discussed and some methods are described. Some examples are finally presented to illustrate the derived model and the proposed methods of estimation.     

冷却剂参数对铣槽喷管低周疲劳寿命的影响

采用有限体积流固耦合计算方法、非线性有限元热结构耦合分析方法和局部应变法研究大面积比铣槽喷管三维再生冷却槽道在循环工作条件下的热结构变形与低周疲劳寿命,并对比分析了冷却剂质量流量与入口温度对铣槽喷管疲劳使用寿命的影响。计算结果表明,铣槽喷管热结构响应呈现复杂的三维效应,应变较大位置主要分布在与肋连接的内衬区域,喷管中部的残余应变量最大;冷却槽道低周疲劳寿命分布和热结构响应基本一致,最小寿命位于喷管中部与肋相连的内衬区域燃气侧;随冷却剂质量流量增加,铣槽喷管低周疲劳寿命不断提高;随冷却剂入口温度增加喷管尾部低周疲劳寿命值不断降低,而喷管中前部的低周疲劳寿命值却不断提高,当冷却剂入口温度为280K左右时,本文的铣槽喷管总体使用寿命达到最大。      

Open spaces for dialogue promoting mental health as a social work education methodology

ABSTRACT

The authors discuss service user involvement as a key approach regarding training of social workers. In many European Union countries this is a stable practice with a lengthy tradition in research and application. However, in Poland it is almost entirely absent and marginalized. This article presents the results of a participatory action research project conducted at the Institute of Sociology of the Jagiellonian University in Krakow, the objective of which was to identify and critically analyze the key substantive and formal aspects of training of social workers with the participation of individuals with experience of mental illness. This research project adopted an open approach to cognizing reality based on qualitative co-participatory methods. In the conclusion, the authors emphasize that the fundamental criterion for the success of this particular form of training is voluntary and differentiated participation of students—both in the role of people sharing their own experience and as learners—as well as shaping a culture of open dialogue, educational alliances of recognition and recovery, the foundation of which is axiological experience.     

关于高周疲劳损伤演化方程的讨论

首先,指出Lemaitre等提出的高周疲劳损伤演化方程只适用于等效应力循环为等幅的加载情形.然后,基于等效应力循环为不等幅的加载情形,推导出适用于高周疲劳的损伤演化方程,说明上述等幅加载情形的损伤演化方程只是高周疲劳损伤演化方程的一个特例,且后者的结果更具一般性.     

天然气工业用户峰谷分时定价多目标优化模型

制定合理的天然气分时定价政策,能够优化资源配置,保证城市天然气管网稳定运行,从而缓解城市“气荒”现象,促进燃气产业健康发展。为此,在考虑用户响应行为的基础上,以最小化最大峰负荷和峰谷负荷差为目标,以燃气公司利益、用户利益,以及政府对天然气价格的限制为约束条件,建立了峰谷分时定价的多目标优化模型,运用遗传算法与Pareto排序相结合的方法对其进行求解。并且,将该模型应用于一个案例,将一天24小时划分为峰、平、谷三个时段,按照“量大价高”的原则实施分时定价政策。结果表明:在保证用户和燃气公司同时获益的情况下,存在最优的峰、平、谷价格,使得最大峰负荷和峰谷负荷差能有效降低,验证了多目标优化模型的有效性和可行性。     

Professional quality of life of adult protective service workers

Adult Protective Services (APS) workers are exposed to substantial occupational hazards and job stress, but these stressors are underdocumented. Therefore, we sought to describe APS workers’ work environments and responses to occupational hazards and stressors, including compassion fatigue, burnout, and secondary traumatic stress. Survey data were gathered with closed-ended questionnaires administered to APS workers in an urban setting. Virtually all workers (97%) reported exposure to one or more environmental hazards in their work, and 80% reported hazard exposure in the past month. Workers also reported mixed responses to their work environment and to experiences with supervision. A sizable minority (22.7%) was at high risk for burnout, 24.6% were at risk for secondary traumatic stress, and 19.9% reported low compassion satisfaction. The results document multiple stressors in APS work. The APS partner is committed to ongoing efforts to better support its staff, and these findings can inform future efforts to enhance supervisor support and worker self-care, to minimize burnout and secondary traumatic stress.     

An equality of condition framework for user involvement in mental health policy and planning: evidence from participatory action research

Discussions about user involvement in the mental health services tend to throw up four major areas of concern: the capacity of service users to participate, their lack of participation skills, the need for a positive organisational culture and the need for arenas of participation. This article presents evidence from participatory action research with Irish mental health service users which explored how they could more equally participate in advisory committees. Participants identified barriers to their equal participation due to unequal cultural, physical, mental and economic resources, time, power, ‘stigma’(prejudice) and lack of respect for their experiential knowledge and emotional expression. These barriers fall within the ‘equality of condition framework’ developed by Baker and colleagues. Enabling equal user involvement in strategic decision‐making requires more than arenas of participation – it requires comprehensively addressing service users’ structural disadvantages throughout the process of involvement.     

Opinion expression via user comments on news websites: analysis through the perspective of the spiral of silence

User comments have become an essential part of news websites. In this article, we examine this mode of public expression via the theory of the spiral of silence. This is done while adopting alternative measures, with regard to three major issues on the Israeli agenda, and in comparison to expression in public, as in the traditional theory. Based on an Internet survey (n?=?712), the present study results support the relevancy of the spiral of silence to the online comment sphere. Perceived support for one’s opinion by the majority was found to have a positive and significant effect on the willingness to express opinion in the online sphere. The explanatory role of fear of isolation was more significant in the online sphere than in face-to-face context.     

What is gained and what is left to be done when content analysis is added to network analysis in the study of a social movement: Twitter use during Gezi Park

As social movements relying on the weak ties found in social networks have spread around the world, researchers have taken several approaches to understanding how networks function in such instances as the Arab Spring. While social scientists have primarily relied on survey or content analysis methodology, network scientists have used social network analysis. This research combines content analysis with the automated techniques of network analysis to determine the roles played by those using Twitter to communicate during the Turkish Gezi Park uprising. Based on a network analysis of nearly 2.4 million tweets and a content analysis of a subset of 5126 of those tweets, we found that information sharing was by far the most common use of the tweets and retweets, while tweets that indicated leadership of the movement constituted a small percentage of the overall number of tweets. Using automated techniques, we experimented with coded variables from content analysis to compute the most discriminative tokens and to predict values for each variable using only textual information. We achieved 0.61 precision on identifying types of shared information. Our results on detecting the position of user in the protest and purpose of the tweets achieved 0.42 and 0.33 precision, respectively, illustrating the necessity of user cooperation and the shortcomings of automated techniques. Based on annotated values of user tweets, we computed similarities between users considering their information production and consumption. User similarities are used to compute clusters of individuals with similar behaviors, and we interpreted average activities for those groups.