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101.
102.
Based on the different roles played by base flow and alternative flow in the process to achieve user’s goals, we have found
that loop structure is frequently used to implement alternative flow and/or to connect different use cases. This paper presents
an approach to identify base flows and alternative flows of different use cases by traversing control flow graph in which
back edges are eliminated. The effectiveness of the approach is verified by identification of the use case structure of an
ATM system. The workload of human intervention of the approach is relatively slight, and the manner of human intervention
closely follows the usual process of software comprehension. 相似文献
103.
张桔 《上饶师范学院学报》2011,31(2):15-20
黑尔认为,伦理学的研究就是对道德语言的逻辑研究。道德语言是一种规定语言,其功能是指导我们的行为,所以道德语言的模糊歧义不仅会造成理论上的困惑,更会引起实践上的混乱。因此,道德语言的明晰十分重要。黑尔对道德语言的分析主要立足于对描述语言和规定语言的比较以及对道德判断和祈使句的比较。按照人们一般的思维模式,文章将从道德概念的分析开始,进而到道德判断,再到道德推理,介评黑尔对道德语言的分析。 相似文献
104.
For analysts there is a tradeoff between the accuracy and the timeliness of their forecasts. Prior literature heavily investigates analyst forecast accuracy. Few papers investigate the importance of timeliness. To our best knowledge, there are no empirical papers to date to investigate the dynamic interplay between these key characteristics. We show that if analysts experience a period of high accuracy relative to their peers, they subsequently focus more on the timeliness of their forecasts in the subsequent period and thus issue their forecasts earlier than they did in the prior period. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
105.
Understory phytomass production in a western juniper ( Juniperus occidentalis ) woodland was examined relative to tree size in central Oregon in 1983 and 1984. Vegetation was sampled in two zones, the canopy zone (beneath the canopy) and the intercanopy zone (the space between canopies), on two adjacent sites—a lower slope site with shallow soil and an upper slope site with deeper soil. Sampling was stratified into three tree size classes. Individual species production was significantly affected by tree size and location relative to tree canopy. Production of bottlebrush squirreltail, bluebunch wheatgrass, cheatgrass, miscellaneous annual grasses, perennial forbs, and annual forbs increased with increasing tree size. Sandberg bluegrass production was greater in the intercanopy than the canopy zone, while production of bottlebrush squirreltail, bluebunch wheatgrass, miscellaneous annual grasses, and both perennial and annual forbs was greater in the canopy zone. Production of cheatgrass was determined by the interaction of tree size and zone. Phytomass relationships were expressed to a greater degree on the upper slope site, where total production exceeded that of the lower slope site by approximately 50% the second year of the study. Individual trees appear to exert a great influence on associated vegetation as western juniper woodlands progress from the seedling (tree establishment) phase to closed stands of mature trees. Original community dominants appear to be spatially segregated beneath tree canopies and associated with large trees, while formerly less common species, such as cheatgrass, come to dominate the entire site. 相似文献
106.
基于总成本分析的全球温室气体减排量谈判囚徒困境博弈模型研究 总被引:1,自引:0,他引:1
以利益关系最对立的发达国家和发展中国家为局中人,建立了囚徒困境博弈模型.通过减排总成本的分析,讨论了全球为将气温变暖限制在2℃以内所应采取的减排量策略组合.研究结果表明碳减排项目在发展中国家运行的总成本更低,因此发达国家通过CDM方式减排是更合理的选择. 相似文献
107.
108.
109.
New use of BCG for recombinant vaccines 总被引:147,自引:0,他引:147
C K Stover V F de la Cruz T R Fuerst J E Burlein L A Benson L T Bennett G P Bansal J F Young M H Lee G F Hatfull 《Nature》1991,351(6326):456-460
BCG, a live attenuated tubercle bacillus, is the most widely used vaccine in the world and is also a useful vaccine vehicle for delivering protective antigens of multiple pathogens. Extrachromosomal and integrative expression vectors carrying the regulatory sequences for major BCG heat-shock proteins have been developed to allow expression of foreign antigens in BCG. These recombinant BCG strains can elicit long-lasting humoral and cellular immune responses to foreign antigens in mice. 相似文献
110.
新挖池塘因无底泥和多数渗水而水质清瘦,但在鱼种放养、水质管理、投饵及防病上,若能扬水质清洁之长,避水质清瘦之短,研究实践证明,是能够取得高产的。 相似文献