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基于3-layer中心度的社交网络影响力最大化算法 被引量:5
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作者 王俊 余伟 +1 位作者 胡亚慧 李石君 《计算机科学》 CSCD 北大核心 2014年第1期59-63,共5页
社交网络影响最大化问题是指如何寻找网络中有限的初始节点,使得影响的传播范围最广。一些贪心算法可以得到较好的影响范围,但是因时间复杂度太高而不适用于大型社交网络。基于度中心性的启发式算法简单但准确度不高;基于介数中心性、... 社交网络影响最大化问题是指如何寻找网络中有限的初始节点,使得影响的传播范围最广。一些贪心算法可以得到较好的影响范围,但是因时间复杂度太高而不适用于大型社交网络。基于度中心性的启发式算法简单但准确度不高;基于介数中心性、接近中心性等全局指标的启发式算法可以较好地识别影响力最大的节点,但计算复杂度也过高。考虑网络节点深层次结构对影响扩散的作用并权衡计算复杂度与准确度,定义了3-layer局部中心度,以计算节点的潜在影响力值。基于线性阈值模型,启发选择一部分种子节点:每一次都选取潜在影响力最大的节点作为种子节点进行激活;运用贪心算法选取剩下的一部分种子节点:每一次都选取具有最大影响增量的节点作为种子节点进行激活。实验表明,该混合算法具有很好的激活范围以及非常低的时间复杂度。 展开更多
关键词 社交网络 影响力最大化 启发式算法 3-layer局部中心度 贪心算法
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A novel 3-layer mixed cultural evolutionary optimization framework for optimal operation of syngas production in a Texaco coal-water slurry gasifier
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作者 曹萃文 张亚坤 +3 位作者 于腾 顾幸生 辛忠 李杰 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第9期1484-1501,共18页
Optimizing operational parameters for syngas production of Texaco coal-water slurry gasifier studied in this paper is a complicated nonlinear constrained problem concerning 3 BP(Error Back Propagation) neural networks... Optimizing operational parameters for syngas production of Texaco coal-water slurry gasifier studied in this paper is a complicated nonlinear constrained problem concerning 3 BP(Error Back Propagation) neural networks. To solve this model, a new 3-layer cultural evolving algorithm framework which has a population space, a medium space and a belief space is firstly conceived. Standard differential evolution algorithm(DE), genetic algorithm(GA), and particle swarm optimization algorithm(PSO) are embedded in this framework to build 3-layer mixed cultural DE/GA/PSO(3LM-CDE, 3LM-CGA, and 3LM-CPSO) algorithms. The accuracy and efficiency of the proposed hybrid algorithms are firstly tested in 20 benchmark nonlinear constrained functions. Then, the operational optimization model for syngas production in a Texaco coal-water slurry gasifier of a real-world chemical plant is solved effectively. The simulation results are encouraging that the 3-layer cultural algorithm evolving framework suggests ways in which the performance of DE, GA, PSO and other population-based evolutionary algorithms(EAs) can be improved,and the optimal operational parameters based on 3LM-CDE algorithm of the syngas production in the Texaco coalwater slurry gasifier shows outstanding computing results than actual industry use and other algorithms. 展开更多
关键词 3-layer mixed cultural evolutionary framework Optimal operation Syngas production Coal-water slurry gasifier
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Study of Dialyzer Membrane (Polyflux 210H) and Effects of Different Parameters on Dialysis Performance
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作者 Md Shihamul Islam Jerzy Szpunar 《Open Journal of Nephrology》 2013年第3期161-167,共7页
Problems frequently encountered in kidney malfunction include abnormal fluid levels in the body, increased acid levels, abnormal levels of Urea, Glucose, Endothelin, β2-Microglobulin and Complement Factor D. Paramete... Problems frequently encountered in kidney malfunction include abnormal fluid levels in the body, increased acid levels, abnormal levels of Urea, Glucose, Endothelin, β2-Microglobulin and Complement Factor D. Parameters characterizing the structure of dialyzers are very important because they decide overall clearance of toxin molecules and at the same time should allow retaining useful molecules in the blood. In this paper, a cross sectional image of the dialyzer membrane with details of the porosity is presented. A multilayered membrane model with different porosity for each layer, describes the actual structure of Polyflux 210H membrane. This model is developed using Finite Element Software—COMSOL Multiphysics 4.3. A blood flow with substances like—Urea, Glucose, Endothelin, β2-Microglobulin, Complement Factor D and Albumin is introduced. For a certain blood flow rate, the toxins diffuse through the membrane and on the other side of the membrane a dialysate flow removes the toxins. Here, different parameters, such as flow rate of blood and dialysate, length and radius of the fiber are changed to simulate how these changes affect toxin clearance and the removal of useful molecules. 展开更多
关键词 Simulation DIALYSIS AXISYMMETRIC Model 3-layered Membrane Effective DIFFUSIVITY PARAMETERS COMSOL MULTIPHYSICS 4.3
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Stress fields caused by a dislocation in an anisotropic 3-layer system 被引量:1
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作者 WANG HuYi YIN YiHui YU ShaoRong 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第3期542-551,共10页
We investigated the stress fields caused by a dislocation in an anisotropic 3-layer system. Based on the image method, the original 3-layer system is firstly decomposed into three infinite homogenous systems. The imag... We investigated the stress fields caused by a dislocation in an anisotropic 3-layer system. Based on the image method, the original 3-layer system is firstly decomposed into three infinite homogenous systems. The image dislocation densities used as unknowns are then strategically distributed in order to satisfy the boundary conditions. The resulting governing equations are singular Cauchy integral ones. Removing the singular terms yields non-linear Fredhom integral equations of the second kind. The obtained stress fields satisfy the boundary conditions, i.e., the traction free condition on the free surface and continuous conditions across the interfaces. Also, a comparison with previous results is made and good agreement is achieved. Numerical investigations show that under the plain strain condition, layer thickness and dislocation position play stronger roles in the stress fields than crystallographic orientation, and these effects more significantly affect the stress fields caused by an edge dislocation than by a screw dislocation. 展开更多
关键词 stress field dislocation anisotropic 3-layer system
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Design and Implementation of an Online Shopping System
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作者 王正杰 张计芬 +1 位作者 赵媛 郭银景 《Journal of Measurement Science and Instrumentation》 CAS 2011年第1期88-91,共4页
The paper puts forward a kind of online shopping system based on ASP. NET technology, including the establishment of data- base anti the design of the front web pages. The system uses Microsoft ASP. NEF as development... The paper puts forward a kind of online shopping system based on ASP. NET technology, including the establishment of data- base anti the design of the front web pages. The system uses Microsoft ASP. NEF as development platform, C as the server language, and Microsoft Visual Studio 2008 as the development tool. ADO. NET is used to connect with SQL SERVER 2000 database through the data- base controls. A variety of server controls are used to create the ASP. NET page to implonent the syste^n functions. The syston is designed in 3-Layer application which includes Presentation Layer (PL), Busi- ness Logic Layer (BLL) and Data Access Layer (DAL). The operation of the database is in DAL, the logic fimction is in BLL. So the amotunt of work in the development, the difficulty of system maintenance and the upgrading can be reduced. After being tested, the system meets the requirement of the users. 展开更多
关键词 online shopping modular design 3-layer structure ordering products
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