基于ISM的地震灾后恢复重建影响因素分析

地震灾后恢复重建是地震灾害受灾国的一项艰巨而繁重的工作任务.地震灾害的破坏性使恢复重建具有复杂性、不确定性和开放性的特点,因此地震灾后恢复重建影响因素不但具有复杂性,而且影响范围和程度也各不相同.引入ISM模型解决了地震灾后恢复重建影响因素多而杂的问题,在文献资料统计基础上构建地震灾后恢复重建影响因子解析结构模型.通过分析确定地震灾后恢复重建关键影响区素共16个:重建主体、重建经验、施工条件、物价、资金、工程成本、建材质量、施工工期、标准施工、检验维修、工程利用、公共服务、自然环境、运行经费、社会饵障、居民激励.该结论为政府优化地震灾后恢复重建工作,保证重建效果具有重要意义.     

A network efficiency measure with application to critical infrastructure networks

In this paper, we demonstrate how a new network performance/efficiency measure, which captures demands, flows, costs, and behavior on networks, can be used to assess the importance of network components and their rankings. We provide new results regarding the measure, which we refer to as the Nagurney–Qiang measure, or, simply, the N–Q measure, and a previously proposed one, which did not explicitly consider demands and flows. We apply both measures to such critical infrastructure networks as transportation networks and the Internet and further explore the new measure through an application to an electric power generation and distribution network in the form of a supply chain. The Nagurney and Qiang network performance/efficiency measure that captures flows and behavior can identify which network components, that is, nodes and links, have the greatest impact in terms of their removal and, hence, are important from both vulnerability as well as security standpoints.     

软件项目风险管理方法的比较与分析

本首先指出了传统的软件管理方法的不足，论述了开展软件项目风险管理的必要性。然后，从基本理论、前沿研究、实践应用、辅助工具和工作标准几个方面，综述了国内外取得的研究成果，继而就2002年来笔收集到的献资料，从成果形式(专、技术报告和论)和内容(一般理论、基本模型、辨识方法、评估方法、辅助工具、经验总结和其它)两方面进行了比较分析，最后结合我国当前的社会和技术环境，提出了应采取树立企业风险化、共享国外成果、建设风险信息数据库和“软”、“硬”结合的四项建议。     

共生视角下我国区域创新生态系统发展观测——基于TOPSIS生态位评估投影模型的时空特征分析

为明确我国区域创新生态系统发展现状,以共生为视角,基于共生单元、共生基质、共生平台、共生网络、共生环境五大生态特征建立区域创新生态系统综合评价指标体系,以2007~2015年我国30个省市相关数据为样本,运用TOPSIS生态位评估投影集成模型及二次加权算法,对我国区域创新生态系统整体及各生态特征的发展状况进行静态和动态综合评价,并分析其时空特征、地区差异及关键因素变迁。结果表明:(1)我国区域创新生态系统发展整体呈趋好态势,东部地区发展趋缓且存在极化现象,中西部地区普遍抬升,地区间发展水平差距较大但随时间推移呈缩小趋势;(2)创新生态系统各生态特征均表现出“东高西低”的地区间非均衡现象,但其时空特征具有显著异质性;(3)区域创新生态系统长远发展的助力优先来自于共生平台和共生网络,而共生单元、共生基质和共生环境的重要性程度呈相对弱化态势。     

双向聚类方法综述

传统的聚类方法由于无法提取样本和变量间的局部对应关系,并且当数据具有高维性和稀疏性时表现不佳,因此学者们提出了双向聚类,基于样本和变量间的局部关系,同时对样本和变量进行聚类,形成一系列子矩阵的聚类结果。近年来,双向聚类发展迅速,在基因分析、文本聚类、推荐系统等领域应用广泛。首先,对双向聚类方法进行梳理与归纳,重点阐述稀疏双向聚类、谱双向聚类和信息双向聚类三类方法,分析它们之间的区别和联系,并且介绍这三类方法在多源数据的整合分析、多层聚类、半监督学习以及集成学习上的发展现状和趋势;其次,重点介绍双向聚类在基因分析、文本聚类、推荐系统等领域的应用研究情况;最后,结合大数据时代的数据特征和双向聚类存在的问题,展望双向聚类未来的研究方向。     

基于分层贝叶斯时空模型的雾霾天气过程计数分析

本文以北京市8个行政区(东城区、西城区、石景山区、海淀区、朝阳区、昌平区、顺义区、怀柔区)的PM2.5指数计算各区逐月雾霞天气过程计数频数为研究对象,选择考虑包括地表温度、相对湿度、平均风速、SO_2质量浓度和NO_2质量浓度在内的5个影响因素。本文定义雾霾天气过程,构建分层贝叶斯时空模型,在一个统计模型中对诸多影响因素进行分析,并从计数分析的角度对北京市雾霾天气现象的时空分布、影响因素进行深入讨论。通过分析得出,温度、湿度、污染物浓度对于雾霾天气过程发生具有促进作用,平均风速对于雾霾天气过程发生具有抑制作用。从时空角度分析,从时间维度上看雾霾天气过程的发生具有明显的季节性特征,冬季(1月、2月)以及3月雾霾天气过程发生次数最高,春季(4月、5月)发生次数最低,秋季发生次数略高于夏季。从空间维度上来看,中心城区(东城区、西城区、石景山、海淀区、朝阳区)雾霾天气过程发生次数明显高于郊区(顺义、昌平、怀柔),以东城区、西城区和朝阳区最为严重。     

Financial Risk Modelling and Econometric Inference

In finance, the explicit modelling of uncertainty takes on a particularly important role. The values of financial derivatives increase in the return volatility of the underlying security. This notion requires a concept of volatility and hence uncertainty. In addition, the choice between modelling in discrete and continuous time is not arbitrary, since it corresponds to a distinction between incomplete and complete markets, respectively, and this distinction matters for asset pricing, financial risk modelling, and inference. Risk and volatility are closely connected, and implied volatility, volatility forecasting, volatility in term structure models, stochastic volatility, and portfolio analysis are considered and related to a more general interplay between cross-sectional and dynamic aspects in finance. Stocks, bonds, and options are considered and placed in the context of efficiency and separation in inference.     

Multimaterial Lattice Structures With Thermally Programmable Mechanical Behaviors北大核心CSCD

传统的点阵结构一旦制备完成,其力学性能通常在使用寿命内保持不变。设计和制造具有环境适应特性的智能点阵结构,可编程地感知和响应外界变化(例如光强、压强、溶液、温度、电磁场、电化学激励),并在时间和空间上进行形状重构、模式转换和性能调控,仍然是人造材料研究领域重要的科学挑战。该文采用具有不同玻璃化转变温度和温度依赖性的多种聚合物材料,通过合理设计材料空间分布,提出了一类具有热可编程力学响应能力的多材料点阵结构。结合理论分析和有限元模拟,研究了组分材料相对刚度对多材料点阵结构的Poisson比、变形模式以及结构稳定性的影响。通过温度变化实现了对多材料点阵结构弹性常数、压溃响应和结构稳定性的调控,使多材料点阵结构表现出极大的热变形、超弹性和形状记忆效应。为设计和制造自适应保护装备、生物医学设备、航空航天领域的变形结构、柔性电子设备、自组装结构和可变形软体机器人等开辟了新途径。     

Building bridges within mathematics education: Teaching, research, and instructional design

Within mathematics education, classroom teachers, educational researchers, and instructional designers share the common goals of understanding and improving the teaching and learning of mathematics. Teachers work to help students learn; researchers study how people learn and teach mathematics; and designers develop instructional materials to support teachers and students. Each community (of teachers, of researchers, and of designers) develops its own perspectives, methods, and expertise. Too seldom, however, do practitioners have the opportunity to share their knowledge across communities. This first-person, retrospective case study speaks to the challenges and rewards of building bridges among these three communities by charting the evolution of an instructional activity (using graphing software to explore slope) through four cycles of teaching, research, and design. Initially separate, the three perspectives of teacher, researcher, and designer begin to interact as the worksite moves from the university laboratory to the author's classroom and then to other teachers’ classrooms. Many of these interactions are fruitful, resulting in new insights and strategies that strengthen the final product and inform the practitioner. At the same time, some tensions arise, particularly between teaching and research, highlighting fundamental differences between these fields. Lessons from this case study suggest implications for collaborations among teachers, researchers, and designers.     

Strongly Gorenstein projective, injective, and flat modules

In this paper, we study a particular case of Gorenstein projective, injective, and flat modules, which we call, respectively, strongly Gorenstein projective, injective, and flat modules. These last three classes of modules give us a new characterization of the first modules, and confirm that there is an analogy between the notion of “Gorenstein projective, injective, and flat modules” and the notion of the usual “projective, injective, and flat modules”.     

A fully coupled method for simulation of wave-current-seabed systems

Coastal flow involves surface wave propagation, current circulation, and seabed evolution, and its prediction remains challenging when they strongly interact with each other, especially during extreme events such as tsunami and storm surge. We propose a fully coupled method to simulate motion of wave-current-seabed systems and associated multiphysics phenomena. The wave action equation, the shallow water equations, and the Exner equation are respectively used for wave, current, and seabed morphology, and the discretization is based on a second-order, flux-limiter, finite difference scheme previously developed for current-seabed systems. The proposed method is tested with analytical solutions, laboratory measurements, and numerical solutions obtained with other schemes. Its advantages are demonstrated in capturing interplay among wave, current, and seabed; it has the capability of first-order upwind schemes to suppress artificial oscillations as well as the accuracy of second-order schemes in resolving flow structures.     

Making Statistics Significant in a Short Course for Graduates with Widely-Varying Non-Statistical Backgrounds

With reference to a short compulsory module for MBA students, this paper discusses how, despite a range of pressures and an extraordinary range of student backgrounds, fears and motivations, it is possible to quickly facilitate understanding and confidence in handling data and basic statistics for graduates in business and associated workplaces. Links and contrasts with a variety of undergraduate teaching scenarios help to enrich teaching and learning strategies, and the strategies and materials developed through interaction with the range of MBA students are transferable to other postgraduate coursework situations. In particular, the need for understanding and confidence in handling data and its presentation, in considering categorical and simple continuous data, and in understanding correlation and association, are common across many different workplaces and applications.     

基于模糊FNN-ELECTRE法的国有商业银行竞争力评价

随着金融业全方位开放,国有商业银行已成为国家经济命脉的核心,其竞争力强弱关系着国家经济的繁荣与衰退。本文基于模糊FNN-ELECTRE方法建立国有商业银行竞争力评价模型,以因素神经网络理论(FNN)与ELECTRE融合方法为基础,以现有商业银行竞争力评价指标为着眼,把国有商业银行竞争力的评价体系从现实竞争力和潜在竞争力两个因素抽取为一级指标,以规模、质量、业务结构、效率、成长性五个因素设为二级指标。从实证的角度对银行A、银行B、银行C、银行D、银行E五大国有银行进行分析验证,对其属性值进行和谐性与非和谐性检验得出,银行B竞争能力最强,银行E竞争能力最弱,五大国有银行均有改进空间。     

中美微积分教材比较研究

微积分课程的教学对高校创新型人才的培养具有重要的作用,其教材建设受到普遍关注.本文以微积分教学方法和教学理念为主线,从教材内容和案例选取、教材结构顺序以及教材表述方式等不同的角度,分析了国内外部分优秀微积分教材所具备的特色.依此为基础,以中美两部具有代表性的微积分教材为比较对象,着重对两本教材在知识点衔接、新知识的引入方式以及提出问题、分析问题的构思方法和阐述方式等具体方面进行了较细致的对比,力图从中展示出中美高等教育在教学思想和表现形式上的某些不同之处,由此得到一些有益的启示.最后,文章列举了美国微积分教材,在语言表达风格、教学案例和习题设计以及教材配套服务等诸多方面值得借鉴的经验和方法.     

On Generalized Integral Means and Euler Type Vector Fields

Formulas for the Euler vector fields, the Neumann derivatives, and the Euler as well as Dirichlet product are derived. Extensions to a Riemann domain of the Gauss operator, the Gauss’ lemma and the related jump formulas are given, and the Gauss–Helmholtz representation with ramifications proved. Examples of elementary solutions to certain modified Laplace operators, applications to pseudospherical harmonics, and characterizations of pseudoradial, pseudospherical, nearly holomorphic, and holomorphic functions, are obtained, and constancy criterion for locally Lipschitz, semiharmonic, respectively, weakly holomorphic functions are given.     

细胞骨架与细胞外基质的力学建模与分析

细胞和生物组织需要适应人体内复杂的力学生物学环境,一方面要被动地承受外部环境中的机械力,另一方面在组织生长、修复等生理过程中要积极主动地产生机械力调整自身的结构和形态.细胞和生物组织的力学性质主要由细胞骨架和细胞外基质决定,它们在微观上都是生物聚合物交联形成的复杂的、各向异性的三维网络结构.这方面早期的力学研究主要集中在通过各种网络模型,理解其普遍存在的非线性响应和硬化行为.近年来随着实验方法、理论建模和计算机模拟技术的大幅进步,这些生命介质的力学性质及其潜在的力学机理得到了更深入的理解.该文回顾了近些年细胞骨架和细胞外基质研究方面取得的部分进展,主要侧重动态交联属性、生物聚合物力学化学耦合赋予的主动材料属性、交联网络塑性和断裂,以及力学训练引发的自适应网络重构.发展细胞骨架与细胞外基质的力学模型与计算方法,分析该类生命介质的复杂力学行为,理解这些力学行为的潜在机制,可以加深我们对细胞和组织的力学生物学认识,并为人造生物材料和细胞组织工程提供基础和参考.     

Nonlinear and Geometric Programming – Current Status

Great strides have been made in nonlinear programming (NLP) in the last 5 years. In smooth NLP, there are now several reliable and efficient codes capable of solving large problems. Most of these implement GRG or SQP methods, and new software using interior point algorithms is under development. NLP software is now much easier to use, as it is interfaced with many modeling systems, including MSC/NASTRAN, and ANSYS for structural problems, GAMS and AMPL for general optimization, Matlab and Mathcad for general mathematical problems, and the widely used Microsoft Excel spreadsheet. For mixed integer problems, branch and bound and outer approximation codes are now available and are coupled to some of the above modeling systems, while search methods like Tabu Search and Genetic algorithms permit combinatorial, nonsmooth, and nonconvex problems to be attacked.     

Operators on Sobolev Type Spaces

In this paper, we introduce the work done on Hardy-Sobolev spaces and Fock-Sobolev spaces and their operators and operator algebras, including the study of boundedness, compactness, Fredholm property, index theory, spectrum and essential spectrum, norm and essential norm, Schatten-p classes, and the $C^∗$ algebras generated by them.