序线性空间中集值优化问题弱有效解的最优性条件

在序线性空间中,引入(u,02;Y+)—广义次似凸集值映射,建立了此映射下的一个择一定理.利用此定理,在序线性空间中获得了带广义不等式约束的集值优化问题弱有效解的最优性必要条件和充分条件.     

择一定理及向量优化问题的Benson真有效性

在局部凸Hausdorff空间中,引入了近次似凸集值映射,建立了近次似凸集值映射下的择一定理.最后,获得了近次似凸集值映射向量优化问题标量下Benson真有效性的一个性质.     

遥感影像在电子地图生产中的应用

以SPOT、TM遥感影像为主要数据源 ,介绍了多源遥感影像融合技术以及电子地图的生产技术流程     

基于S3C2410TK开发平台的嵌入式导航系统应用研究

随着嵌入式设备的日臻完善，导航系统正逐渐向小型化、专业化方向发展。文章介绍了SAMSUNG公司推出的基于ARM920T内核的S3C2410TK硬件开发平台．讨论了以EVC＋＋4．O为系统软件开发工具，实现对城区GIS的GPS导航。重点介绍了多线程技术，电子地图的读取和显示等关键技术。     

几种人工智能技术在入侵检测系统中的应用

介绍几种人工智能技术,如多层感知机网络、自组织映射网络和支持向量机等,以及这些技术在入侵检测系统中的应用.     

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货运车辆行车途中能否有安全便利的休息站,关系到联邦关于司机工作时间规定的执行及高效的车队运营.由于货运车辆的激增,中途停车站能力短缺问题日益凸显.本研究开发了一个基于互联网的地理信息系统,用于从用户大范围收集停车位短缺的地理信息.为了分析这些停车紧张点的地理分布,采用了点聚合和排名的方法来发现停车问题最严重的地区.另外,提出一种沿公路方向的单测度的聚合方法.其基本思路是,停车问题不是一个单点问题,而是一个区域性问题.缓解停车紧张,可通过增加区域性停车能力.本文发现能力紧张的区域通常在大都市的郊区,反映出很多长途司机在此停车等待第二天往市区内送货的运作规律.研究结果与来自公路巡警方面的观察结果一致.     

Provably Secure Short Proxy Signature Scheme from Bilinear Maps

An enhanced formal model of security for proxy signature schemes is presented and a provably secure short proxy signature scheme is proposed from bilinear maps. The proposed proxy signature scheme is based on two short secure signature schemes. One is used for delegating the signing rights and computing the standard signature; the other is used for computing proxy signature. Finally, a security proof of the proposed proxy signature scheme is showed by reducing tightly the security of the proposed proxy signature scheme to the security of the two basic signature schemes. The proposed proxy signature scheme has the shortest ordinary signatures and proxy signatures. Moreover, the proxy signature generation needs no pairing operation and verification needs just two pairing operation.     

分形元胞自动机在自组织临界性中的应用

基于元胞自动机分形模型，探讨了散粒体自组织临界性（SOC）的机制．不同级配散粒体单面坡的已有试验表明，散粒体的SOC与非均匀系数有关．应用分形理论计算了沙堆颗粒级配的分维数，结果表明，呈现SOC的沙堆，颗粒级配具有分形特征．进而假设：若大尺度非均匀沙系统的组构特征具有分形特性，系统也能呈现SOC．为解释此假设，建立了既能表征非均匀系数又具有分形组构特征的元胞自动机沙堆模型．数值模拟表明，元胞排列方式服从分形时，沙堆模型呈现SOC，而等间隔排列的模型不呈现SOC，结果与假设一致．最后对SOC的判据进行了讨论，认为系统组构特征具有分形特性是大尺度非均匀沙系统呈现SOC的必要条件．     

到球面上的四维非齐次双调和映射连续性

对到球面上的四维非齐次双调和映射,本文根据球面的几何结构和四维Lorentz空间的特殊性,得到了在Lorentz空间的估计式,从而得到其弱解的连续性结果.     

Classifying Ports for Efficiency Benchmarking: A Review and a Frontier-based Clustering Approach

Abstract

Port efficiency and port clustering are two aspects that have received different degrees of attention in the existing literature. While the actual estimation of port efficiency has been extensively studied, the existing literature has paid little attention to developing robust methodologies for port classification. In this paper, we review the literature on classification methods for port efficiency, and present an approach that combines stochastic frontier analysis, clustering and self-organized maps (SOM). Cluster methodologies that build on the estimated cost function parameters could group ports into performance metrics’ categories. This helps when setting improvement targets for ports as a function of their specific cluster. The methodology is applied to a database of Spanish port authorities. The dendrogram features three clusters and five outlier Spanish Port Authorities. SOM are employed to track the temporal evolution of Spanish Port Authorities that are of special interest for some reasons (i.e. outliers). Results show that use of a combination of cost frontier and cluster methods to define robust port typology and SOMs, jointly or in isolation, offers useful information to the decision-makers.