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In cloud computing system,it is a hot and hard issue to find the optimal task scheduling method that makes the processing cost and the running time minimum. In order to deal with the task assignment,a task interaction graph was used to analyze the task scheduling; a modeling for task assignment was formulated and a particle swarm optimization (PSO)algorithm embedded in the variable neighborhood search (VNS) to optimize the task scheduling was proposed. The experimental results show that the method is more effective than the PSO in processing cost,transferring cost, and running time. When the task is more complex,the effect is much better. So,the algorithm can resolve the task scheduling in cloud computing and it is feasible,valid,and efficient. 相似文献
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通过对标准粒子群优化算法中惯性权重的分析和对耗散理论的研究,提出了一种惯性权重正弦调整的耗散粒子群优化算法(S-DPSO),并对该算法进行了深入的分析和研究.通过对4个典型函数的仿真测试,试验结果表明S-DPSO在收敛速度和全局收敛性方面都比标准粒子群优化算法、随机惯性权重粒子群优化算法、惯性权重正弦调整粒子群优化算法、耗散粒子群优化算法和随机惯性权重耗散粒子群优化算法有明显改进.理论分析和仿真试验验证了S-DPSO的正确性和有效性. 相似文献
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岷江叠溪古堰塞湖的发现 总被引:13,自引:0,他引:13
1933年8月25日,四川岷江上游叠溪发生了一次7.5级地震.在叠溪地震引发的较场大滑坡上覆盖有较古老的厚土层,国内学者对其成因有不同解释.作者在开展叠溪地震滑坡调研中,发现并确认这是一套古堰塞湖相沉积物,当时的堰塞坝处在原叠溪古镇至下游马老顶乡一带长达数千米的河段,因此定名为叠溪古堰塞湖.古堰塞湖相沉积物厚度最大可达200余米,为一套层理清晰的粉土-黏土层.由叠溪向上游约30 km河段,沿江断续可见这套沉积物,且有明显的相变.14C测年,湖相沉积物底部形成时代距今22 ka,顶部距今约10 ka,据此判断叠溪古堰塞湖维持了12 ka.此外作者在较场一带还发现了以湖相沉积物为"基座"的五级"阶地",这些"阶地"上保存完好的二元结构河流相沉积物.该文较系统地介绍了叠溪古堰塞湖的基本特征,初步论述了其中包含的地质环境信息. 相似文献
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对天童常绿阔叶林内林隙的形成特征进行了研究,结果表明:该地区林隙的线密度为17.08个&;#8226;km-1,扩展林隙所占面积比例为15.42%,冠空隙所占的比例为5.46%.冠空隙的年形成频率为0.287%,林隙形成的返回间隔期为348.4 a左右.林隙的面积普遍偏小,扩展林隙面积在39.3~251.2 m2之间,平均面积为106.32 m2,冠空隙大小变化在11.8~131.9 m2之间,平均面积为37.68 m2.树木枯立、风灾以及对病树的人为择伐是该地区林隙的主要形成方式,木荷、马尾松、栲树和石栎等乔木层常见种类是其主要形成木.在山坡上部、中部和下部等不同地形条件下分别以风灾、枯立和择伐为主要方式形成林隙.调查的41个林隙中,每个林隙的形成木平均拥有量仅为1.71株.形成木径级主要分布在20~40 cm范围内,平均基径为28.93 cm. 相似文献
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模拟电路故障信号的小波预处理 总被引:4,自引:0,他引:4
针对模拟电路故障诊断的神经网络存在结构规模较大的问题,提出一种基于小波一神经网络的模拟电路故障诊断方法。该法采用冲激响应来获取模拟电路的故障信号,采用小波变换作为模拟电路故障信号的预处理器,利用Haar小波分层次分解提取故障信号特征,该信号特征经主元分析和数据标称化后,作为用于故障诊断的神经网络的输入。基于该法故障诊断的基本原理,对一实例电路进行故障划类、小波函数及故障特征选择,给出计算故障特征的仿真编程及故障类别的识别方法。该法大大减少用于故障诊断的神经网络的输入数目,简化它的结构和减少其训练处理的时间。仿真结果表明,该法可以提高模拟电路故障诊断的效率和辨识故障类别的能力。 相似文献
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钢骨混凝土异型柱框架模型地震反应分析 总被引:2,自引:2,他引:0
运用大型有限元分析软件ANSYS 9.0对钢骨混凝土异型柱框架和普通混凝土异型柱进行振型分析,得到了该框架的自振特性;并输入E1-Centro波和宁河天津(N-S)波,对两种异型柱结构进行了抗震性能的时程分析.本文所得结果,可为工程设计参考. 相似文献
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Relationship between alanine aminotransferase levels and metabolic syndrome in nonalcoholic fatty liver disease 下载免费PDF全文
Zhou-wen CHEN Li-ying CHEN Hong-lei DAI Jian-hua CHEN Li-zheng FANG 《浙江大学学报(自然科学英文版)》2008,(8):616-622
Objective: To investigate the relationship between alanine aminotransferase (ALT) levels and metabolic syndrome (MS) in nonalcoholic fatty liver disease (NAFLD). Methods: A total of 26527 subjects who received medical health checkup in our hospital from January 2005 to July 2007 were enrolled in the study. The diagnosis of fatty liver was based on ultrasound imaging. MS was defined according to the criteria of the Adult Treatment Panel III. ALT, triglyceride (TG), high density lipoprotein cholesterol (HDL-c), fasting plasma glucose (FPG), height, weight, waist circumference (WC), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured in each subject to analyze the relationship between MS and ALT activity Results: (1) The prevalence of NAFLD in men (30.94%) was significantly higher than that in women (15.65%); (2) The incidence of MS in NAFLD (33.83%) was significantly greater than that in non-NAFLD (10.62%); (3) Of the 6470 subjects with NAFLD, in the age-adjusted partial correlation analysis, there were statistically significant correlations between the ALT levels and most metabolic risk factors in each sex (P〈0.01), except that ALT levels multiple stepwise regression analysis, SBP lost its significance, and had no correlation with HDL-c in women. Moreover, in the WC, body mass index (BMI), age, DBP, TG and FPG were independently associated with ALT levels in both sexes (P〈0.05). HDL-c remained significant and was independently related to ALT levels in men; (4) ALT levels were significantly higher in subjects with MS compared to those without MS (P〈0.001). Mean ALT levels increased with the number of MS components in each sex (P〈0.05 for trend). Conclusion: We found a strong relationship between ALT levels and MS in NAFLD and revealed that the cluster of MS components might be the predictor for ALT elevations. 相似文献