Function oriented service composition modeling

Formal models for service composition have been proposed with the variation of the requirements of service developers. Some famous models have provided checking and verification techniques and tools for the behavior of service composition. These models generally focus much on the message flow of web services and neglecting the data contained in the exchanged messages among services, which restrict the application range of these models and also the web service techniques. As new kind of services with different protocols and communication methods have appeared, it is needed to model service composition from a new view which is adapted to the new development in service area. In this paper we offer a function oriented model of service composition which treats the composite service as a software system and specify the function of services which can be directly used to the realization by service providers.     

Helping Homeless Families Overcome Barriers to Successful Functioning

The author articulates key stressors in the lives of families who are homeless. These stresses often combine with barriers such as lack of job opportunities and/or insensitive professionals. Strategies for helping homeless families overcome these barriers and related issues are presented.     

高中物理学习困难的成因分析及对策研究

物理难学,这似乎已成为高中学生的共识。笔者经过大量调查研究发现造成这种状况的原因很多,单就学的方面而言,大多数同学主要是由于怕学、厌学或不会学物理。调查结果显示,物理学习困难的学生,在进入高中前就对物理学习心存惧怕,其中有30%左右的同学,一遇到困难就轻言放弃;另有50%左右的同学对物理学习虽也信心不足,但一开始还是下定决心要学好物理,他们在物理学习上化了大量时间、精力,不可谓不刻苦,不能说没努力,但由于缺乏兴趣,学习物理对他们来说是一种被迫行为,体会不到学习中的乐趣,时间一长,必然觉得学习枯燥无味,变成了一种苦差事,…     

The relation of multiple-schedule behavioral contrast to deprivation,time in session,and within-session changes in responding

Pigeons' keypecking was reinforced by food on baseline schedules of multiple variable interval (VI) x VI x and on contrast schedules of multiple VI x VI y. Deprivation of food was varied by maintaining subjects at 75%, 85%, and 95% (+/- 2%) of their free-feeding weights. Positive and negative behavioral contrast were observed. The size of the contrast was not systematically altered by changes in deprivation. Positive and negative contrast were both larger later in the session than they were earlier. Within-session decreases in responding were steeper for the baseline than for the contrast schedules for positive contrast. Within-session decreases were steeper for the contrast than for the baseline schedules for negative contrast. These results were predicted by the idea that different amounts of habituation to the reinforcer during the baseline and contrast schedules contribute to behavioral contrast. The results show that contrast occurs under conditions that reduce the effect of the following component. The results support the assumption that positive and negative contrast are produced by symmetrical theoretical variables.     

极小极大方法在二阶Hamilton系统中的应用

本文综述了用极小极大方法得到的关于二阶Hamilton系统周期解的可解性条件及相关结果,包括次线性条件,次二次条件和超二次条件等方面的近期结果。     

Impact of brief or extended extinction of a taste aversion on inhibitory associations: Evidence from summation,retardation, and preference tests

In five conditioned taste aversion experiments with rats, summation, retardation, and preference tests were used to assess the effects of extinguishing a conditioned saccharin aversion for three or nine trials. In Experiment 1, a summation test showed that saccharin aversion extinguished over nine trials reduced the aversion to a merely conditioned flavor (vinegar), whereas three saccharin extinction trials did not subsequently influence the vinegar aversion. Experiment 2 clarified that result, with unpaired controls equated on flavor exposure prior to testing; the results with those controls suggested that the flavor extinguished for nine trials produced generalization decrement during testing. In Experiment 3, the saccharin aversion reconditioned slowly after nine extinction trials, but not after three. Those results suggested the development of latent inhibition after more than three extinction trials. Preference tests comparing saccharin consumption with a concurrently available fluid (water in Experiment 4, saline in Experiment 5) showed that the preference for saccharin was greater after nine extinction trials than after three. However, saccharin preference after nine extinction trials was not greater, as compared with that for either latent inhibition controls (Experiments 4 and 5) or a control given equated exposures to saccharin and trained to drink saline at a high rate prior to testing (Experiment 5). Concerns about whether conditioned inhibition has been demonstrated in any flavor aversion procedure are discussed. Our findings help explain both successes and failures in demonstrating postextinction conditioned response recovery effects reported in the conditioned taste aversion literature, and they can be explained using a memory interference account.     

现代远程教育的比较优势

本文以“十六”大报告提出的形成全民学习、终身学习的学习型社会,构建终身教育体系为理论依据,将远程教育的教育模式与传统教育的教育模式相比较,从教育师资的供需矛盾、远程教育教学媒体的多样化、教学支持服务体系的建立及教学资源库的形成进行了充分的比较论述,同时为教育投资取向提出了理论依据。     

师生冲突的概念界定与分类探究——基于刘易斯·科塞的冲突分类理论

论文通过借鉴和辨析社会学理论中的冲突概念,对师生冲突概念作出界定。根据美国当代社会学家刘易斯·科塞的冲突分类理论,对学校师生冲突进行分类研究。在此基础上提出了三个观点:学校师生冲突的多数属于非现实性冲突;师生结构由紧密走向松散是师生冲突增多的重要原因;师生冲突具有一定的正面功能。