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计算布尔差分与布尔偏导数的表格方法 被引量:2
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作者 刘观生 陈偕雄 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2006年第9期1486-1489,共4页
为了简化Reed-Muller型逻辑函数的布尔差分与布尔偏导数的计算过程,提出了一种基于表格的新方法.该方法通过用表格列出Reed-Muller型逻辑函数的1值积项,并对1值积项中相应的位取1到0的变换产生新项来计算一阶布尔差分.二阶布尔差分通过... 为了简化Reed-Muller型逻辑函数的布尔差分与布尔偏导数的计算过程,提出了一种基于表格的新方法.该方法通过用表格列出Reed-Muller型逻辑函数的1值积项,并对1值积项中相应的位取1到0的变换产生新项来计算一阶布尔差分.二阶布尔差分通过两次变换产生新积项,并删除相同积项来得到.一阶布尔偏导数作为一阶布尔差分,二阶布尔偏导数通过对积项中相应位作两次连续的1到0的变换来得到.该方法用表格模拟了计算布尔差分与布尔偏导数的过程.应用结果表明,与图形方法相比较,该方法不需要画图,操作简便,可适合求解多变量逻辑函数以及计算机编程. 展开更多
关键词 RM展开 表格方法 布尔差分 布尔偏导数
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知识引导的快速表格分割方法研究
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作者 高明 朱志莹 陈熙霖 《微电子学与计算机》 CSCD 北大核心 1991年第2期33-35,共3页
数据录入的低效率一直是影响OA 和数据库应用发展的因素之一.改善这一途径就是发展数据自动录入技术.本文讨论了自动报表录入系统中的分割算法,针对表格的多样性,提出一种在图象知识库支持下的快速分割算法,并在应用中取得了较好的效果.
关键词 数据库 知识引导 快速表格分割方法 知识库 数据录入
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技术直达列车开行的车流量下限标准判断系统设计
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作者 林柏梁 田亚明 +2 位作者 李沛恒 王志美 纪丽君 《铁路计算机应用》 2010年第6期22-24,共3页
本文将表格化查询方法应用到车流量强度判断中,提出了系统目标、特点和架构,并详细分析了系统的各个功能模块,为建立技术直达列车开行的车流量下限标准判断系统,给出了完整的开发途径和应用方法。系统解决了以往依靠人工经验判断车流量... 本文将表格化查询方法应用到车流量强度判断中,提出了系统目标、特点和架构,并详细分析了系统的各个功能模块,为建立技术直达列车开行的车流量下限标准判断系统,给出了完整的开发途径和应用方法。系统解决了以往依靠人工经验判断车流量标准,缺乏科学理论依据的问题。 展开更多
关键词 表格化查询方法 技术直达列车 车流量 系统设计
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Ship Hull Form Optimization by Evolutionary Algorithm in Order to Diminish the Drag 被引量:2
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作者 Hassan Zakerdoost Hassan Ghassemi Mahmoud Ghiasi 《Journal of Marine Science and Application》 2013年第2期170-179,共10页
This study presents a numerical method for optimizing hull form in calm water with respect to total drag which contains a viscous drag and a wave drag. The ITTC 1957 model-ship correlation line was used to predict fri... This study presents a numerical method for optimizing hull form in calm water with respect to total drag which contains a viscous drag and a wave drag. The ITTC 1957 model-ship correlation line was used to predict frictional drag and the corrected linearized thin-ship theory was employed to estimate the wave drag The evolution strategy (ES) which is a member of the evolutionary algorithms (EAs) family obtains an optimum hull form by considering some design constraints. Standard Wigley hull is considered as an initial hull in optimization procedures for two test cases and new hull forms were achieved at Froude numbers 0.24, 0.316 and 0.408. In one case the ES technique was ran for the initial hull form, where the main dimensions were fixed and the only variables were the hull offsets. In the other case in addition to hull offsets, the raain dimensions were considered as variables that are optimized simultaneously. The numerical results of optimization procedure demonstrate that the optimized hull forms yield a reduction in total drag. 展开更多
关键词 OPTIMIZATION evolutionary algorithms drag thin-shiptheory
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Numerical Simulation and Experiment on Dam Break Problem 被引量:7
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作者 胡长洪 末吉诚 《Journal of Marine Science and Application》 2010年第2期109-114,共6页
In this paper, two novel numerical computation methods are introduced which have been recently developed at Research Institute for Applied Mechanics ( R/AM ), Kyushu University, for strongly nonlinear wave-body inte... In this paper, two novel numerical computation methods are introduced which have been recently developed at Research Institute for Applied Mechanics ( R/AM ), Kyushu University, for strongly nonlinear wave-body interaction problems, such as ship motions in rough seas and resulting green-water impact on deck. The first method is the CIP-based Cartesian grid method, in which the free surface flow is treated as a multi-phase flow which is solved using a Cartesian grid. The second method is the MPS method, which is a so-called particle method and hence no grid is used. The features and calculation procedures of these numerical methods are described. One validation computation against a newly conducted experiment on a dam break problem, which is also described in this paper, is presented. 展开更多
关键词 CIP method MPS method darn break experiment
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A Free Surface Frequency Domain Green Function with Viscous Dissipation and Partial Reflections from Side Walls 被引量:2
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作者 Hongde Qin Jing Shen Xiaobo Chen 《Journal of Marine Science and Application》 2011年第3期259-264,共6页
The free-surface Green function method is widely used in solving the radiation or diffraction problems caused by a ship or ocean structure oscillating on the waves. In the context of inviscid potential flow, hydrodyna... The free-surface Green function method is widely used in solving the radiation or diffraction problems caused by a ship or ocean structure oscillating on the waves. In the context of inviscid potential flow, hydrodynamic problems such as multi-body interaction and tank side wall effect cannot be properly dealt with based on the traditional free-surface frequency domain Green function method, in which the water viscosity is omitted and the energy dissipation effect is absent. In this paper, an open-sea Green function with viscous dissipation was presented within the theory ofvisco-potential flow. Then the tank Green function with a partial reflection from the side walls in wave tanks was formulated as a formal sum of open-sea Green functions representing the infinite images between two parallel side walls of the source in the tank. The new far-field characteristics of the tank Green function is vitally important fur improving the validity of side-wall effects evaluation, which can be used in supervising the tank model tests. 展开更多
关键词 Green function viscous dissipation side wall effect partial reflection
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