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81.
82.
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. 相似文献
83.
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. 相似文献
84.
In 1981, the career structure in Dutch higher education was modified in such a way that performance criteria, particularly possession of a doctorate and research and publication activity, were required for promotion. In particular, the hierarchy of university posts below that of full professor was modified in such a way that persons holding so‐called WHM(senior scientific staff level) positions were required to reapply for the new UHD(associate professor) positions on a competitive basis which stressed the publication record of candidates. Using a sampling of academic women drawn from the natural sciences, the authors offer an explanation as to why women academics did less well than men in the competitions for these new posts. Although the process did not discriminate against women as such, it did not favour academics on the periphery of the profession, where many women at the time found themselves. The situation identified was the result of social factors more than of institutional discrimination. Presently, younger women ‐graduate students ‐ are rapidly moving from the periphery of the profession to the centre. Active involvement in professional networks will aid academic women in their careers; however, over‐involvement in family matters (the care network) may be harmful to the career progress of academic women. 相似文献
85.
Reading and listening progress in segregated primary schools: Does ethnic and socioeconomic classroom composition matter?
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Lisa Dewulf Johan van Braak Mieke Van Houtte 《British Educational Research Journal》2017,43(5):931-951
This study aimed to investigate the relationship of classroom composition factors with reading and listening comprehension achievement and progress in socially and ethnically segregated primary schools in Flanders (Belgium). Specifically, using a three‐level multivariate repeated measures analysis, it examined the association of reading and listening achievement and progress with ethnic diversity, the proportion of non‐native students and the average socioeconomic status of the class, taking into account student characteristics. At the beginning and end of the school year, reading tests, listening tests and questionnaires were administered to a sample of 7‐ and 8‐year‐old students (n = 683) in 42 second‐grade classes. Students' listening comprehension achievement at the beginning of the school year was negatively related to having a home language other than the language of instruction and to classes with a high proportion of non‐native students. However, progress in listening comprehension was not significantly associated with any student or classroom composition factors. Students whose mothers had a lower level of education performed lower on reading comprehension at the beginning of the school year, while at the end of the school year students whose mothers had a higher level of education were at a greater disadvantage. Limitations of this study and directions for future research are discussed. 相似文献
86.
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. 相似文献
87.
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. 相似文献
88.
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 总被引:15,自引:0,他引:15
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。 相似文献
89.
石敏俊 《浙江大学学报(A卷英文版)》2004,5(12):1533-1542
Land degradation is one of the severe environmental problems in China. In order to combat land degradation, a soil conservation program was introduced since 2000 to reduce soil erosion by converting slope-cultivated land into forestry and pasture. This paper represents the first systematic attempt to investigate the impact of the soil conservation program on land degradation in the loess plateau. The results indicate that the soil conservation program to convert slope fields into forest or pasture is an effective way to combat soil erosion. However, a subsidy that is higher than profit of land use activity of slope fields before their conversion into forest and pasture is needed to encourage farmers to join the conservation program. A policy measure to encourage and assist farmers to develop sedentary livestock by using crops produced from fields as well as fodder and forage grass from the converted slope fields might contribute to combat soil erosion. Increase in off-farm job opportunities may encourage households to reduce cultivation in slope fields. That implies a policy measure to encourage rural urbanization might contribute to combat soil erosion. 相似文献
90.
ABSTRACTWhen searching for information on the Internet, it can be stored in a bookmarking system. The ability to organize this information in such a system depends on one’s own prior knowledge to create an appropriate classification scheme. Providing a classification system for bookmarks might support people with low prior knowledge. Even though different bookmarking systems exist, hierarchical menus and tagging are being most widely used. In the current exploratory study with 95 ninth-grade students, a 2 × 2 between-subjects design was used to investigate the influence of providing classification support (or not) for either a tagging or a hierarchical system. Results showed that despite the low familiarity with tagging systems, using a hierarchical system is not necessarily a better approach than using a tagging system to organize previously found information. Rather, a tagging system seems to yield storage of fewer but higher-quality information sources. The most important conclusion is that, despite the low familiarity with tagging systems, using a hierarchical system was not beneficial over using a tagging system to organize previously found information. 相似文献