具有边权特性的社会网络重要成员识别

根据成员间关系的强弱给社会网络中各边赋予权重,将二元网络扩展到边权网络,提出一种新的度量指标。该指标通过累加一个成员在网络中成为关键点的次数来度量其删除后给整个网络带来的损害程度,从而判断该成员对维护网络运行绩效的重要性。通过组织沟通网络的实例分析,说明新指标可以从维护网络安全的视角,有效辨识那些虽然结构位置不显著,但对网络安全具有重大隐患的重要成员。     

TEI@I方法论及其在外汇汇率预测中的应用

基于TE I@I方法论的理论框架,构建了一个基于TE I@I方法论的外汇汇率预测模型。在此模型中,传统的经济计量模型用于处理外汇汇率的主要趋势,人工神经网络技术用于分析外汇汇率的非线性,而文本挖掘和专家系统用于处理外汇市场中的突现性和不稳定性。最后,基于集成的思想,利用支持向量回归技术对上述3个部分进行非线性集成,从而获得一个更为精确的预测结果。通过实证方法验证了基于TE I@I方法论的外汇汇率预测模型的有效性。     

公司运营危机预警模型的比较研究——以中国上市公司为例

研究当前国内外公司运营危机预警问题的现状,首先要寻找一套适合于我国上市公司的财务状况识别指标体系,然后依据该指标体系采用不同方法建立运营危机预警模型,最后利用样本公司实际指标数据对各个模型的短期及中期预警效果进行比较分析与实证研究。结果表明,分类树模型的三年期预警准确率都在80%以上。     

基于贝叶斯正则化的TDBPNN模型在中国外贸预报中的应用及评估

基于相空间重构的非线性预报思想,建立一个时滞的BP神经网络模型(TDBPNN),采用贝叶斯正则化方法提高BP网络的泛化能力,并将该模型应用于中国进出口贸易的预测,结果证明改进的TDBPNN模型具有较好的泛化能力,准确拟合了进出口贸易发展的历史值和趋势。区别于一般的预测评价,认为非线性预测不仅要注重数据拟合和精度改进,而且应该能够反映被预报系统的非线性特征。在分析模型预测精度的同时,通过计算拟合序列和原序列的非线性特征量进行模型评价,证实预测模型能够合理地“捕捉”到产生原序列的非线性系统的动力学特征。     

一种基于闭排队网络的集装箱码头设备配置优化模型

将集装箱码头龙门吊装卸工艺抽象为闭排队网络模型,采用估算均值法计算了顾客到达和服务时间分布为一般情况的闭排队网络系统性能指标.仿真结果表明,闭排队网络模型计算结果可以为集装箱码头设备配置提供一定的决策支持.     

Data relaying with constraints in hierarchical sensor networks

In this paper we present and discuss several optimisation problems that arise in the management of data flow in wireless sensor networks (WSNets). We consider a hierarchical architecture for WSNets composed of sensors, relays, and relay gateways. Sensors send data they generate at a known average bit rate to relays in one hop. The relay nodes use a multi-hop mechanism to reach a set of assigned gateways which then forward the data directly to the base station. We are concerned with finding an assignment of relay gateways to relays so that certain constraints are satisfied. We define a unified model in which constraints such as lifetime, data delay, and data flow splitting are formulated in terms of four optimisation problem in graphs.     

城域网MAC层协议的优先级结构及性能

主要研究城域网MAC层标准“IEEE 802.6 DQDB”协议的优先故排队性能;提出了一种DQDB协议的优先级实现方案—β分级结构。通过本文给出的文件传输性能分析以及计算机模拟证明,这种新的优先级结构可取得比DQDB现有结构更好的性能,而且易于实现。     

城市老年人子女亲属网与子女外亲属网差序性的实证研究——以烟台市向阳街道三居民小区为例

本文依据2006年8月—9月份我院《胶东城乡老龄化问题》研究小组对烟台市向阳街道三个居民小区老年人进行的问卷调查数据资料,运用社会网络分析方法,探讨了城市老年人子女亲属网与子女外亲属网的差序性及其影响因素。本研究认为,城市老年人的亲属人际关系网存在内在差序性,这种差序性的形成与城市老年人社会经济地位及其亲属交往频度显著相关。     

Two-level network design with intermediate facilities: An application to electrical distribution systems

We consider the two-level network design problem with intermediate facilities. This problem consists of designing a minimum cost network respecting some requirements, usually described in terms of the network topology or in terms of a desired flow of commodities between source and destination vertices. Each selected link must receive one of two types of edge facilities and the connection of different edge facilities requires a costly and capacitated vertex facility. We propose a hybrid decomposition approach which heuristically obtains tentative solutions for the vertex facilities number and location and use these solutions to limit the computational burden of a branch-and-cut algorithm. We test our method on instances of the power system secondary distribution network design problem. The results show that the method is efficient both in terms of solution quality and computational times.     

The duration of residence spells among Malawians: the role of established family and friend connections at migrants’ destinations

It is well-documented that established networks in a destination increase the chances of an individual moving to that destination, but rarely have migration scholars examined how these networks are linked to the duration of one’s stay. This paper examines whether the presence of kin and/or friends known at a location prior to moving is associated with one’s duration of residence. Presumably, having both kin and friends already at a destination will be associated with the longest residence spells, since migrants would likely maximise their access to diverse network resources. Using residence history data on 1069 Malawians from the Migration and Health in Malawi (MHM) Project from 2013, subtle gender differences emerge in this relationship via discrete-time event history analyses. Women who knew some friends, but no kin, prior to migrating have a significantly lower likelihood of moving away in any year compared to those who did not know anyone, or only kin. For men, knowing some friends, but no kin, does not represent a significantly lower likelihood of leaving compared to those who knew no one or only kin prior to migrating.