On the assignment of students to topics: A Variable Neighborhood Search approach

This article presents a study of a practical assignment problem found in teaching within higher education. Here, students are assigned to scientific topics for which written papers must be submitted. Often, preferences across topics exist among other side constraints that should be considered in solving the problem of interest. Characterizing attributes of real-world problems were studied for scientific departments in Economics and Business Administration at German universities by sending out 800 questionnaires, and analyzing the 203 responses.Based on earlier studies, a Variable Neighborhood Search (VNS) approach was formulated to solve the resulting assignment problem. Several neighborhood search operators were tested, and numerical results are reported for a range of problem scenarios taken from real-world cases. It was observed that VNS leads to superior results vs. single operator local search approaches. Furthermore, we were able to show that in the studied problem, the effectiveness of certain neighborhoods was, to a large extent, dependent on the structures of the underlying problem.An extension of the problem was formulated by integrating a second objective function, which simultaneously balances the workload of staff members while maximizing student utility. The VNS approach was implemented in a computer system, available free of charge, providing decision support for selected other institutions within higher education.     

关于船员外派法律关系的分析——兼析《船员条例》和《船员注册管理办法》

金融危机席卷全球,进一步证明了经济的全球化趋势,外派劳务市场也未幸免,船员外派作为外派劳务市场的一个重要组成部分,受到了严重的影响。而目前的《船员条例》和《船员注册管理办法》在起到规范作用的同时,也受到了法律效力过低的限制。文中旨在分析船员外派法律关系,更好地去保障船员的权益,并结合《条例》和《办法》去发现其中存在的问题。     

双层金属腔体HEMP平面波孔缝耦合特性分析

高空核爆电磁脉冲（HEMP）对电子/电气设备构成严重威胁,是电磁兼容与电子/电气 设备安全领域的重要研究内容。基于时域有限差分法（FDTD）的总场-散射场体系建立仿真 空间,推导了连接边界的一维平面波引入方法,选择双层金属腔体为研究对象,仿真分析了 腔体在HEMP平面波作用下透过孔缝在各采样点的响应过程。仿真结果显示,各采样点都出现 了明显的振荡波形,其中外金属腔体孔缝中心比内金属腔体内部中心点耦合电场的峰值大; 相同面积下,正方形孔、矩形孔的耦合电场比圆孔的耦合电场小;内部腔体与外部腔体 在孔缝一侧距离的大小也会对耦合结果产生影响,间距越大,内部耦合电场的衰减越多。所 得结论 有利于指导双层金属腔体的电磁防护设计。     

基于BWAS的无线传感器网络静态分簇路由算法

为提高路径搜索效率,避免动态分簇较多的能量消耗,提出了基于最优-最差蚂蚁系统(BWAS )的无线传感器 网络静态分簇路由算法。BWAS是对蚁群算法的改进,在路径搜寻过程中评价出最优最差蚂蚁 ,引入奖惩机制,加快了路径搜索速度。通过无线传感器网络静态分簇、簇内动态选举簇头 ,在簇头节点间运用BWAS算法搜寻从簇头节点到汇聚节点的多跳最优路径,能减少路径寻优 能量消耗,实现均衡能量管理,延长网络寿命,且具有较强的鲁棒性。通过与基于BWAS的 动态分簇和基于蚁群算法的动态分簇路由的仿真实验相比较,证实了本算法的有效性。     

宽带小型化U型贴片天线的设计

设计了一副中心频率为2 GHz的四分之一波长U型贴片天线。采用U型槽加载减小了探针 电感,使天线实现双谐振工作,通过将双频比调整到接近为1以展宽天线的工作频带,设计 出的天线的带宽达49%(VSWR<2)。利用短路墙加载技术,使天线的尺寸在四分之一波长 左右 ,减小了天线尺寸,天线的尺寸仅为295 mm×40 mm×12 mm。实际制作了该 天线,测试结果与 理论分析基本吻合,验证了设计的正确性。该天线结构简单,便于设计以及加工制作,同时 方便集成于移动通信设备中。     

数字化变电站设计简述

文章介绍了桂林500 kV变电站柳桂乙线数字化间隔,对IEC 61850协议、智能开关、电子式互感器、数字式计量系统进行了分析,阐述了现阶段500kV数字化变电站的实施方案,分析了数字化变电站技术与常规变电站设计的区别,论述了建设该数字化变电站的先进性、安全性、可靠性,并指出了数字化变电站建设是变电站未来发展的必然趋势.     

SIP与H．323协议互通研究

在SIP网络出现之前,以IP网络为传输系统的H．323网络已得到广泛应用,因此,应用SIP网络时必须考虑SIP网络和H．323网络的互联问题。文章研究SIP网络与H．323网络互通的功能实体IWF（互通的功能实体称为IWF,即Inter Working Function互通功能体）,经测试此方案是合理可行的。     

SPECTRUM LICENSING AND FLEXIBLE BEAUTY CONTEST DESIGNS

McMillan's (1995) ‘flexibility’ proposition suggests a testable hypothesis about beauty contests spectrum assignments. Such flexibility purportedly allows regulators to pursue social welfare (network deployment) goals. A separate argument is that more competitive beauty contests enhance the probability of assignment. The study concludes that regulators do indeed focus on societal (network deployment) welfare goals. Initially, consideration is given in the immediate term where licenses are awarded based on operator aftermarket commitments. Subsequently, spectrum package attributes and financial performance obligations, specified in the tender documents, come into play to support the networks spread more widely through the population in a timely manner. Finally, the econometric results suggest that more competitive beauty contests enhance the probability of assignment.     

基于VMI的中低压配网物资协议库存采购模式研究

协议库存采购是国家电网公司为提高中低压配电工程物资供应的时效性对配网的部分物资实行协议库存采购货物招标的一种新的采购模式。为提高供应商的准时供货率,保障物资供应,在供应商管理库存（VMI）的基础上,将电网企业的物资采购与库存方式相结合,提出了VMI协议库存采购模式及具体的实施方式。