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A hybrid two-stage flowshop scheduling problem was considered which involves m identical parallel machines at Stage 1 and a burn-in processor M at Stage 2, and the makespan was taken as the minimization objective. This scheduling problem is NP-hard in general. We divide it into eight subcases. Except for the following two subcases： （1） b≥ an, max{m, B} 〈 n; （2） a1 ≤ b ≤ an, m ≤ B 〈 n, for all other subcases, their NP-hardness was proved or pointed out, corresponding approximation algorithms were conducted and their worst-case performances were estimated. In all these approximation algorithms, the Multifit and PTAS algorithms were respectively used, as the jobs were scheduled in m identical parallel machines. 相似文献
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The combination of online or semi-online with deterioration jobs has never been researched in scheduling problems. In this paper, two semi-online parallel machine scheduling problems with linear deterioration processing time are considered. In the first problem, it is assumed that the deterioration rates of jobs are known in an interval, that is, bj ∈[0, α], where 0 〈α≤ 1 and bj denotes the linear deterioration rate. In the second problem, it is assumed that the largest deterioration rate of jobs is known in advance, that is, b = max1≤j≤n {bj }. For each of the two problems, a heuristic MBLS algorithm is worked out and its worst-case ratio is analyzed. At the same time, the worst-case ratio of the list （LS） algorithm is investigated and it is proved that all the ratios are tight. 相似文献
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聘任制作为学校管理机制改革的重要内容,从理论的提出、方案的论证,到实践探索的,直到今天的大范围推广经验,至少已有十几年的经历。成效明显,经验也似乎很丰富。但我认为仍有一些问题尤其是隐性问题还值得进一步思考、研究。问题一:关于教师聘任的周期当前大多数实行聘任制的学校,在其实施方案中,教师聘任期一般是一年。通常在学生入学前(暑假前或暑假中)进行聘任,学年终结时即次年暑假前终止聘任。以一年为周期的聘任制具有一定的优点。如,聘期恰好与学年工作并轨运行,有利于安排工作,也有利于及时考核、重新聘人,具有灵活性。聘任时,一学… 相似文献
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林嘉佳是高密市疏港区至诚幼儿园的一名单亲幼儿,这几天她特别高兴,因为前不久,她的家长领到了政府发放的1200元学前教育助学金银行卡。嘉佳的妈妈刘美娟感动地说:"这是政府给咱老百姓办的一件大好事,有了这个补助卡,小佳等于免费上幼儿园。"像林嘉佳一样,高密市有3000多名贫困、孤残幼儿都领到了助学银行卡,2012年全市发放助学金仅学前教育一项就达184.83万元。受益的不仅是学生。从2012年1月开始,高密市9000多名教师平均涨工资200元。此前,高密市已经连续4年提高教师工资1300多元。 相似文献
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年终岁尾,做好一年总结,对于鼓舞思想、凝聚力量、引领师生成长、促进新年工作具有重要意义。长期以来,我们注重总结形式,强调书面总结,把总结作为任务指令,形成了敷衍应付、套搬照抄、教条主义、只见工作不见人的现象,损伤了干部、教师的积极性,也失去了总结的本义。这促使我们思考:应该如何革除弊端,创新形式,把年终总结变成全体师生共同参 相似文献
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