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无界凸多面体由“和形式”向“交形式”的转化 被引量:4
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作者 魏权龄 汪俊 闫洪 《系统工程理论与实践》 EI CSCD 北大核心 2004年第3期87-90,共4页
凸多面体可以表示成一组线性不等式的交 ,称这种表示为凸多面体的“交形式”;同时 ,它也可以由其全部极点和对应的凸多面锥的全部极方向生成 ,称之为“和形式”.将一个凸多面体在“和形式”与“交形式”之间进行转化是数学规划中的一个... 凸多面体可以表示成一组线性不等式的交 ,称这种表示为凸多面体的“交形式”;同时 ,它也可以由其全部极点和对应的凸多面锥的全部极方向生成 ,称之为“和形式”.将一个凸多面体在“和形式”与“交形式”之间进行转化是数学规划中的一个基本问题 .本文使用类似线性规划中的“大 M-方法”,构造性地将无界凸多面体“和形式”的凸多面体转化为“交形式”,并用数值例子说明了该算法的应用过程 . 展开更多
关键词 无界凸多面体 “和形式” “交形式” 数学规划
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DEA的非参数规模收益预测方法 被引量:13
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作者 魏权龄 张倩伟 《中国管理科学》 CSSCI 2008年第2期25-29,共5页
本文运用"交形式"生产可能集,对于具有多种生产要素投入的"生产部门",给出非参数方法所确定的多个变量的生产函数,进而讨论了当投入规模增大时,判别规模收益将处于递增、不变、递减、"饱和"和"拥挤&... 本文运用"交形式"生产可能集,对于具有多种生产要素投入的"生产部门",给出非参数方法所确定的多个变量的生产函数,进而讨论了当投入规模增大时,判别规模收益将处于递增、不变、递减、"饱和"和"拥挤"状态的充分必要条件。这对于每个决策单元("企业"或"部门")相对而言是否需要扩大规模和如何扩大规模给出科学的分析。 展开更多
关键词 “交形式”生产可能集 非参数的生产函数 规模收益
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生产前沿面的规模收益结构分析 被引量:2
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作者 张倩伟 《统计与决策》 CSSCI 北大核心 2010年第14期56-58,共3页
文章运用DEA理论中的"交形式"生产可能集,从生产前沿面的结构角度,根据规模收益的"动态"判别方法,对处于不同规模收益状态下的生产前沿面以及各规模收益状态之间的前沿"交界面"进行分析,并对相应的生产... 文章运用DEA理论中的"交形式"生产可能集,从生产前沿面的结构角度,根据规模收益的"动态"判别方法,对处于不同规模收益状态下的生产前沿面以及各规模收益状态之间的前沿"交界面"进行分析,并对相应的生产前沿面及前沿"交界面"的特征给予刻画,从而为研究整个生产过程的规模收益现状和发展趋势以及决策单元规模收益状况的变动范围提供有利的理论依据。 展开更多
关键词 DEA “交形式”生产可能集 生产前沿面 规模收益
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Interactive Generalization on Large-Scale Topographical Map Supported by a Database Platform
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作者 CAIZhongliang WUHehai +1 位作者 DUQingyun LIAOChujiang 《Geo-Spatial Information Science》 2003年第4期17-26,共10页
This paper makes astudy on the interactive digital gener-alization, where map generalizationcan be divided into intellective reason-ing procedure and operational proce-dure, which are done by human andcomputer, respec... This paper makes astudy on the interactive digital gener-alization, where map generalizationcan be divided into intellective reason-ing procedure and operational proce-dure, which are done by human andcomputer, respectively. And an inter-active map generalization environmentfor large scale topographic map is thendesigned and realized. This researchfocuses on: ① the significance of re-searching an interactive map generali-zation environment, ② the features oflarge scale topographic map and inter-active map generalization, ③ the con-struction of map generalization-orien-ted database platform. 展开更多
关键词 large scale topographic map interactive generalization data platform
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Audit Committees: How They Affect Financial Reporting in Nigerian Companies
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作者 Abdulkadir Madawaki Noor Afza Amran 《Journal of Modern Accounting and Auditing》 2013年第8期1070-1080,共11页
This study examines whether audit committees are associated with improved financial reporting quality for a sample of Nigerian listed companies prior to and after a corporate governance code mandated new regulations f... This study examines whether audit committees are associated with improved financial reporting quality for a sample of Nigerian listed companies prior to and after a corporate governance code mandated new regulations for audit committees in 2003. Using a sample of 70 companies listed on the Nigerian Stock Exchange, this study uses archival data in the form of companies' annual reports to measure the association between audit committees and improved financial reporting quality. Dechew and Dichev (2002)'s model was used to measure earnings as a proxy for financial reporting quality. The results indicate that formation of audit committees was positively associated with improved financial reporting quality. It was also found that audit committees having an independent chair and audit committee expertise were positively associated with financial reporting quality. Other audit committee characteristics examined were found to be insignificantly related to financial reporting quality. 展开更多
关键词 audit committees financial reporting quality Nigerian listed companies
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Dynamic Portfolio Choice under Uncertainty about Asset Return Model
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作者 何朝林 孟卫东 《Journal of Donghua University(English Edition)》 EI CAS 2009年第6期645-650,共6页
The effect of uncertainty about stochastic diffusion model on dynamic portfolio choice of an investor who maximizes utility of terminal portfolio wealth was studied.It applied stochastic control method to obtain the c... The effect of uncertainty about stochastic diffusion model on dynamic portfolio choice of an investor who maximizes utility of terminal portfolio wealth was studied.It applied stochastic control method to obtain the closed-form solution of optimal dynamic portfolio,and used the Bayesian rule to estimate the model parameters to do an empirical study on two different samples of Shanghai Exchange Composite Index.Results show,model uncertainty results in positive or negative hedging demand of portfolio,which depends on investor's attitude toward risk;the effect of model uncertainty is more significant with the increasing of investment horizon,the decreasing of investor's risk-aversion degree,and the decreasing of information;predictability of risky asset return increases its allocation in portfolio,at the same time,the effect of model uncertainty also strengthens. 展开更多
关键词 dynamic portfolio model uncertainty estimation risk Bayesian analysis
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Formal Verification in 3oux Tripartite Diffie-Hellman Protocol
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作者 祝烈煌 张子剑 +2 位作者 王峰 郭聪 袁彩霞 《China Communications》 SCIE CSCD 2012年第3期153-163,共11页
Security analysis of cryptographic protocols has been widely studied for many years.As far as we know,we have not found any methods to effectively analyze group key exchange protocols for the three parties yet,which d... Security analysis of cryptographic protocols has been widely studied for many years.As far as we know,we have not found any methods to effectively analyze group key exchange protocols for the three parties yet,which did not sacrifice the soundness of cryptography.Recently,Canetti and Herzog have proposed Universally Composable Symbolic Analysis(UCSA) of two-party mutual authentication and key exchange protocol which is based on the symmetric encryption schemes.This scheme can analyze the protocols automatically and guarantee the soundness of cryptography.Therefore,we discuss group key exchange protocol which is based on Joux Tripartite Diffie-Hellman(JTDH) using UCSA.Our contribution is analyzing group key exchange protocol effectively without damaging the soundness of cryptography. 展开更多
关键词 UCSA computationally sound JTDH group key exchange protocol
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Integrating Interaction Framework for Agent Negotiation
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作者 肖正光 cs. sjtu. edu. cn +3 位作者 王振杰 cs. sjtu. edu. cn 徐良贤 cs. sjtu. edu. cn 《Journal of Donghua University(English Edition)》 EI CAS 2003年第4期76-82,共7页
Agent negotiation has become increasingly important since the advent of electronic commerce.There are two kinds of interactions in the process of agent negotiation.One is the interaction between different agents,and t... Agent negotiation has become increasingly important since the advent of electronic commerce.There are two kinds of interactions in the process of agent negotiation.One is the interaction between different agents,and the other is the interaction between the agent and the human user.In this paper,firstly,we introduce Q language,a scenario description language for designing interactions between agents and human users.Then we propose an integrating interaction framework for agent negotiation,in which both kinds of interactions are described by Q scenario.Our framework can make the interaction process open and easy to be understood by the users.Users can understand how the negotiation process goes and what is happening in the system including some erroneous or inappropriate actions caused by the negotiation agent.This gives the users a chance to terminate or change the behavior of negotiation agent in time to avoid unfavorable negotiation outcome.In addition,users can customize the agent's behaviors through visible interactions with it. 展开更多
关键词 automated negotiation interactive agent agent-mediated e-commerce
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IC Reporting in Traditional Sectors of Malaysian Public Listed Firms
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作者 Wan Fadzilah Wan Yusoff Wan-Leng Lim 《Journal of Modern Accounting and Auditing》 2011年第9期966-973,共8页
One of the significant effects of the knowledge economy is the introduction of new business models with resulting creation of intangible resources represented by intellectual assets. In spite of its clear contribution... One of the significant effects of the knowledge economy is the introduction of new business models with resulting creation of intangible resources represented by intellectual assets. In spite of its clear contribution to a firm's sustainability of performance, recognition of these intellectual assets in the financial statements do not correspond with their significance as they have to rigid criteria set by conventional accounting standards. This study seeks to assess the level of intellectual capital (IC) resources reported in Malaysian companies in the traditional sectors of the economy and examine their reporting trends in the annual reports of these companies from years 2003 and 2008 Data was collected from companies listed in the main board of Malaysia Stock Exchange (or Bursa Malaysia) and content analysis was applied. Results show that the extent of IC reporting in the annual accounts of listed companies in traditional sectors is slightly above average. 展开更多
关键词 intellectual capital financial reporting DISCLOSURES intellectual assets MALAYSIA
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DEA与数据挖掘 被引量:8
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作者 魏权龄 王鑫 《数学的实践与认识》 CSCD 北大核心 2009年第24期141-151,共11页
使用Wei和Yan给出的凸多面体的"和形式"与"交形式"相互转化的方法,得到"交形式"的生产可能集TWY,以及由此判别相对效率的方法,研究DEA用于数据挖掘,处理具有"海量"决策单元的相对效率评价(包... 使用Wei和Yan给出的凸多面体的"和形式"与"交形式"相互转化的方法,得到"交形式"的生产可能集TWY,以及由此判别相对效率的方法,研究DEA用于数据挖掘,处理具有"海量"决策单元的相对效率评价(包括技术有效性和规模收益递增、不变、递减以及"拥挤"迹象).给出的方法只需使用一个"交形式"的生产可能集,与本作者先前的"DEA评测机"相比,可以节省很多计算量.方法是对DEA评测机的一种新的改进,是对数据挖掘领域的一个补充. 展开更多
关键词 DEA “交形式”生产可能集 规模收益 数据挖掘
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规模收益状况的动态因素分析 被引量:1
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作者 张倩伟 《数学的实践与认识》 CSCD 北大核心 2010年第16期31-35,共5页
基于DEA理论的"交形式"生产可能集,从投入增大和缩小两种角度,对多投入多产出生产系统的各种规模收益状态进行分析,研究部分投入要素变化对部分产出要素的作用效果,即对规模收益状况给予"动态"因素分析,得到判定部... 基于DEA理论的"交形式"生产可能集,从投入增大和缩小两种角度,对多投入多产出生产系统的各种规模收益状态进行分析,研究部分投入要素变化对部分产出要素的作用效果,即对规模收益状况给予"动态"因素分析,得到判定部分投入与部分产出之间规模收益各种状态的充要条件,从而为研究规模收益各状态的产生原因提供理论依据. 展开更多
关键词 规模收益 DEA “交形式”生产可能集 动态分析
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Analysis of thin plates by the weak form quadrature element method 被引量:8
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作者 ZHONG HongZhi YUE ZhiGuang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第5期861-871,共11页
The recently proposed weak form quadrature element method (QEM) is applied to flexural and vibrational analysis of thin plates The integrals involved in the variational description of a thin plate are evaluated by a... The recently proposed weak form quadrature element method (QEM) is applied to flexural and vibrational analysis of thin plates The integrals involved in the variational description of a thin plate are evaluated by an efficient numerical scheme and the par- tial derivatives at the integration sampling points are then approximated using differential quadrature analogs. Neither the grid pattern nor the number of nodes is fixed, being adjustable according to convergence need. The C~ continuity conditions char- acterizing the thin plate theory are discussed and the robustness of the weak form quadrature element for thin plates against shape distortion is examined. Examples are presented and comparisons with analytical solutions and the results of the finite element method are made to demonstrate the convergence and computational efficiency of the weak form quadrature element method. It is shown that the present formulation is applicable to thin plates with varying thickness as well as uniform plates. 展开更多
关键词 C1 continuity mesh distortion thin plate weak form quadrature element
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The separable Hamiltonian system and complete biorthogonal expansion method of Mindlin plate bending problems 被引量:5
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作者 HOU GuoLin QI GaoWa +1 位作者 XU YaNan CHEN Alatancang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第5期974-980,共7页
A separable Hamiltonian system of Mindlin plate bending problems is obtained. Using the equivalence between the differen form and integral form of the separable Hamiltonian system, the biorthogonal relationships of th... A separable Hamiltonian system of Mindlin plate bending problems is obtained. Using the equivalence between the differen form and integral form of the separable Hamiltonian system, the biorthogonal relationships of the eigenfunctions are presen! Based on the biorthogonal relationships, a novel complete biorthogonal expansion of the Mindlin plate bending problems x~ two opposite sides simply supported is proposed through the products of operator matrices. The exact solutions to deflections bending moments for the Mindlin plate with fully simply supported sides are obtained. A numerical example is illustrated to ve~ the accuracy and validity of the expansion method. 展开更多
关键词 separable Hamiltonian system mindlin plate bending biorthogonal expansion off-diagonal Hamiltonian operator
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Tunneling conductance in graphene ferromagnet/p wave superconductor junctions
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作者 LI XiaoWei CHEN HuaBao LIU ShuJing 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第4期649-653,共5页
Using the extended Blonder-Tinkham-Klapwijk formalism, we investigate the conductance spectra of graphene ferromagnet/p wave superconductor junctions. It is found that the conductance spectra are affected by the p wav... Using the extended Blonder-Tinkham-Klapwijk formalism, we investigate the conductance spectra of graphene ferromagnet/p wave superconductor junctions. It is found that the conductance spectra are affected by the p wave pairing symmetry. The ferromagnetic exchange energy in the ferromagnet can suppress Andreev retroreflection but enhance the specular Andreev reflection in graphene ferromagnet/p wave superconductor junctions. The conductance decreases with increasing exchange energy Eh for Eh〈Er (the Fermi energy in the ferromagnet region), but the conductance increases with increasing exchange energy Eh for Eh〉EF. 展开更多
关键词 GRAPHENE FERROMAGNET p wave superconductor tunneling conductance
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Sexual selection on color and behavior within and between cichlid populations: Implications for speciation 被引量:1
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作者 Michael J.PAUERS Jeffrey S.MCKINNON 《Current Zoology》 SCIE CAS CSCD 2012年第3期475-483,共9页
Sexual selection is widely viewed as playing a central role in haplochromine cichlid speciation. Hypothetically, once divergent mate preferences evolve among populations of these fishes, reproductive isolation follows... Sexual selection is widely viewed as playing a central role in haplochromine cichlid speciation. Hypothetically, once divergent mate preferences evolve among populations of these fishes, reproductive isolation follows and the populations begin to behave as different species. Various studies have examined patterns of assortative mating among species and sometimes populations, but few have examined variation in directional preferences, especially among populations of the same species. We investi- gated mate choice behavior in two populations of Labeotropheus fueUeborni, a Lake Malawi endemic. We test whether mating preferences between populations are based on the same traits and in the same direction as preferences within populations. We examine the potential contributions of two classes of trait, color patterns and behaviors, to reproductive isolation. When females chose between either two males of their own population, or two from another, female preferences were generally similar (for the female population) across the two contexts. Mate choice patterns differed between (female) populations for a measure of color, but only modestly for male behavior. In a separate experiment we simultaneously offered females a male of their own population and a male from a different population. In these trials, females consistently preferred males from their own population, which were also the males that displayed more frequently than their opponents, but not necessarily those with color traits suggested to be most attractive in the previous experiment. Thus directional preferences for chroma and related aspects of color may be important when females are presented with males of otherwise similar phenotypes, but may play little role in mediating assortative mating among populations with substantially different color patterns. A preference for male behavior could play some role in speciation if males preferentially court same-population females, as we have observed for the populations studied herein [Current Zoology 58 (3): 475-483, 2012]. 展开更多
关键词 Haplochromine cichlid Sexual selection SPECIATION COLOR Labeotropheus
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Conformal oscillator representations of orthogonal Lie algebras
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作者 XU XiaoPing 《Science China Mathematics》 SCIE CSCD 2016年第1期37-48,共12页
The conformal transformations with respect to the metric defining the orthogonal Lie algebra o(n, C) give rise to a one-parameter (c) family of inhomogeneous first-order differential operator representations of th... The conformal transformations with respect to the metric defining the orthogonal Lie algebra o(n, C) give rise to a one-parameter (c) family of inhomogeneous first-order differential operator representations of the orthogonal Lie algebra o(n + 2, C). Letting these operators act on the space of exponential-polynomial functions that depend on a parametric vector a^→∈ C^n, we prove that the space forms an irreducible o(n + 2, C)-module for any c ∈ C if a^→ is not on a certain hypersurface. By partially swapping differential operators and multiplication operators, we obtain more general differential operator representations of o(n+2, C) on the polynomial algebra in n variables. Moreover, we prove that l forms an infinite-dimensional irreducible weight o(n +2, C)-module with finite-dimensional weight subspaces if c Z/2. 展开更多
关键词 orthogonal Lie algebra differential operator oscillator representation irreducible module poly- nomial algebra exponential-polynomial function
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