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分布式存储中文件分割的最优化模型 被引量:5
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作者 陈卫卫 吴海佳 胥光辉 《解放军理工大学学报(自然科学版)》 EI 北大核心 2010年第4期413-416,共4页
在分布式存储中,由于网络与存储节点的不稳定性,会导致文件存储过程失败。通过对文件进行适当的分割存储可以提高文件存储过程成功的概率。建立了网络存储节点可用性概率模型和文件块网络存储成功的概率模型,给出了文件分割存储策略,比... 在分布式存储中,由于网络与存储节点的不稳定性,会导致文件存储过程失败。通过对文件进行适当的分割存储可以提高文件存储过程成功的概率。建立了网络存储节点可用性概率模型和文件块网络存储成功的概率模型,给出了文件分割存储策略,比较了在不同分割粒度下文件网络存储成功的概率,提出了分布式存储中文件分割的最优化模型,通过该模型可计算出大小为X的文件进行分布式存储时最优的分割块数。该模型对大文件的分布式存储具有一定的参考价值。 展开更多
关键词 分布式存储 存储节点可用性 文件分割 最优化分割
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聚合物驱后二元复合驱油藏的层系调整——以孤东油田七区西为例 被引量:21
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作者 陆雪皎 王友启 +3 位作者 魏翠华 潘广明 郭兰磊 元福卿 《油气地质与采收率》 CAS CSCD 北大核心 2014年第2期25-28,112-113,共4页
胜利油区的聚合物驱后油藏剩余储量丰富,现有的层系井网已不能满足后续开发的要求,为了更好地通过细分层系达到提高采收率和增加经济效益的目的,以孤东油田七区西二元复合驱油藏为代表,利用油藏数值模拟方法对聚合物驱后二元复合驱油藏... 胜利油区的聚合物驱后油藏剩余储量丰富,现有的层系井网已不能满足后续开发的要求,为了更好地通过细分层系达到提高采收率和增加经济效益的目的,以孤东油田七区西二元复合驱油藏为代表,利用油藏数值模拟方法对聚合物驱后二元复合驱油藏进行层系调整研究。以化学驱投资与成本构成分析为基础,依据动态经济评价方法,建立了一套适用于聚合物驱后二元复合驱油藏开发的层系调整界限图版;应用此图版结合熵权算法计算得到的油藏各小层非均质综合指数和聚类分析确定的最优化分割方案,筛选出满足要求的最优化分割方案。依此方法对孤东油田七区西聚合物驱后二元复合驱油藏进行层系调整,调整后效果显著,采收率提高了3.45%,财务净现值增加了174.6×104元。 展开更多
关键词 聚合物驱后 二元复合驱 层系调整界限 熵权算法 最优化分割方案 孤东油田
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Optimal Differentiation Pricing Policy with Linear Demand Function
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作者 唐小我 张明善 《西南民族学院学报(哲学社会科学版)》 北大核心 2003年第4期102-105,共4页
The main objective in any marketing effort is to consider the optimal conditions to maximize revenue and profit. The optimal market segmentation prici ng strategy is investigated under the assumption of an aggregate l... The main objective in any marketing effort is to consider the optimal conditions to maximize revenue and profit. The optimal market segmentation prici ng strategy is investigated under the assumption of an aggregate linear demand f unction. The optimal conditions to maximize revenue and profit, two closely corr elative problems, are obtained respectively. The differentiation pricing policy described here can be easily applied in practice. A numerical example is provide d which vividly illustrates the advantage of applying optimal policies. 展开更多
关键词 价格政策 最优化分割 价格歧视 线性需求函数 税收 利润 分化价格
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一种改进自适应阈值的Canny算法 被引量:14
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作者 于晓海 张阳 须颖 《机械与电子》 2020年第1期6-9,共4页
针对传统Canny算法在滤波时无差别平滑降噪、边缘信息丢失及模糊的现象,且人工选取梯度高低阈值存在局限性的问题,提出了综合考虑图像位置信息与亮度信息的双边滤波代替传统高斯滤波方法,结合最优化阈值分割法和Otsu法分别计算出图像高... 针对传统Canny算法在滤波时无差别平滑降噪、边缘信息丢失及模糊的现象,且人工选取梯度高低阈值存在局限性的问题,提出了综合考虑图像位置信息与亮度信息的双边滤波代替传统高斯滤波方法,结合最优化阈值分割法和Otsu法分别计算出图像高低阈值,采用边缘信噪比SNR函数对比验证边缘检测效果。改进后的Canny算法有效提高了边缘完整性,且伪边缘更少,对图像中相对较弱的边缘部分也有良好的提取效果,改进后的算法具有更高的信噪比。采用工业机械臂视觉采集零件边缘为背景,实验结果表明,改进后的Canny算法可以有效保留真实边缘信息,边缘更加连续且完整。 展开更多
关键词 CANNY算子 边缘检测 双边滤波 OTSU法 最优化阈值分割 信噪比
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Finite Element Analysis and OADs Optimization of the Temperature in the Plane-strain Orthogonal Metal Cutting Process 被引量:1
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作者 刘龙权 姚振强 袁光杰 《Journal of Donghua University(English Edition)》 EI CAS 2004年第4期29-33,共5页
In order to analyze the influences of the different tool’s shape and surface conditions (such as different coated and material) and their interaction on the cutting temperature, a coupled thermo-mechanical finite ele... In order to analyze the influences of the different tool’s shape and surface conditions (such as different coated and material) and their interaction on the cutting temperature, a coupled thermo-mechanical finite element analysis (FEA) model of plane-strain orthogonal metal cutting process is constructed, and 16 simulation cases with 16 different types of tools, which cover 4 rake angles, -10°, 0°, 10°, 20°, and 4 friction coefficient values, 0, 0.1, 0.2, 0.3 in the same cutting condition (cutting depth and cutting speed) have been performed. Finally the simulation results are analyzed according to the variance analysis method (VAM) of orthogonal array designs (OADs), the relationships between the rake angle, tool-workpiece interface’s friction coefficient and their interact effect to the maximum temperature value and the temperature field of the chip are obtained. This result has some instructive meaning to analyze the causes of the cutting temperature and to control the maximum temperature value and the overall temperature field in the metal cutting process. 展开更多
关键词 FEA Metal cutting OADs Interact effect Maximum temperature value.
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Study on maximum efficiency control strategy for induction motor
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作者 刘小虎 谢顺依 郑力捷 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2007年第4期588-592,共5页
Two new techniques for efficiency-optimization control(EOC) of induction motor drives were proposed. The first method combined Loss Model and "golden section technique", which was faster than the available m... Two new techniques for efficiency-optimization control(EOC) of induction motor drives were proposed. The first method combined Loss Model and "golden section technique", which was faster than the available methods. Secondly, the low-frequency ripple torque due to decrease of rotor flux was compensated in a feedforward manner. If load torque or speed command changed, the efficiency search algorithm would be abandoned and the rated flux would be established to get the best transient response. The close agreement between the simulation and the experimental results confirmed the validity and usefulness of the proposed techniques. 展开更多
关键词 induction motor efficiency optimization control search controller golden section technique loss model controller
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Global optimization design method for maximizing the capacity of V-belt drive 被引量:5
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作者 ZHANG ShaoJun WAN Zhong LIUGuangLian 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第1期140-147,共8页
An optimization model is constructed to formulate the maximization problem on the capacity of V-belt drive. The concavity,the monotonicity and the global optimality condition are studied for the objective function,and... An optimization model is constructed to formulate the maximization problem on the capacity of V-belt drive. The concavity,the monotonicity and the global optimality condition are studied for the objective function,and it is proved that the feasible region of the model is bounded,closed and convex under some design conditions. Then,a solution method,called an optimal segment algorithm,is developed to find the global maximizer of the model. Under four different design conditions,solution methods are presented respectively. Some real case studies are employed to demonstrate that the model and the algorithm in this paper are promising. 展开更多
关键词 V.belt global optimization capacity of drive optimal segment algorithm
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