Freedom of access to the radio spectrum for satellite communications

A conference will open on 8 August 1985 under ITU auspices to consider major procedural changes in the international regulation of the use of the radio spectrum by geostationary satellites. There has been strong pressure for the introduction of a priori orbit/ spectrum planning for, for example, the fixed-satellite service from countries which foresee that they may lose their option to set up domestic satellite networks under the present ptocedure. However, reform of the present procedures, rather than radical change, would give better assurance that the real needs of all countries will be met.     

IP电话系统网守的研究与实现

IP电话系统是具有广阔发展前景的新型电信业务。研究了在H .32 3协议下 ,IP电话系统中网守所起的作用 ,探讨了具有地址映射、域管理、呼叫代理、计费功能的网守的实现方案 ,并对该网守的特点进行了分析。     

基于IP的SAN存储技术研究

存储区域网络(SAN，即Storage Area Network)是一个连接服务器和存储设备的网络，是存储区域中最流行的技术。先分析了存储体系结构中各种存储技术的特点，讨论了存储技术的经典发展；在介绍了IP存储网络协议的同时，详细阐述和分析了基于iSCSI协议的IP SAN环境；然后讨论了SAN的另一种实现方式——IPSAN与InfiniBand服务器结构的整合，最后预测了SAN存储技术的未来发展。     

基于遗传算法的自动化立体仓库的货位优化分配

文章针对自动化立体仓库的库区和货位的分配策略问题进行了讨论,提出立体仓库的库区优化数学模型：在库区优化基础上,进一步提出货位优化数学模型．将Pareto最优解的概念与遗传算法相结合,提出了一种改进的解决多目标优化问题的Pareto遗传算法解决货位优化问题．给出了仿真实验及分析,结果表明采用改进遗传算法优化策略可以有效地解决自动化立体仓库的货位优化分配问题。     

多目标模糊指派模型在物流配送环节中的应用研究

在建立多目标模糊指派问题数学模型的基础上,对该模型的求解算法进行深入研究,并通过实例分析说明了多目标指派模型在物流配送环节中的适用性,验证了该模型对于达到物流配送环节的经济、合理、最优化的目标有着现实意义。     

Integrated Berth Allocation and Quay Crane Assignment Problem: Set partitioning models and computational results

Most of the operational problems in container terminals are strongly interconnected. In this paper, we study the integrated Berth Allocation and Quay Crane Assignment Problem in seaport container terminals. We will extend the current state-of-the-art by proposing novel set partitioning models. To improve the performance of the set partitioning formulations, a number of variable reduction techniques are proposed. Furthermore, we analyze the effects of different discretization schemes and the impact of using a time-variant/invariant quay crane allocation policy. Computational experiments show that the proposed models significantly improve the benchmark solutions of the current state-of-art optimal approaches.     

基于多损伤感知的全光网络RWA算法研究

全光网络中如何规避物理层损伤实现光信号高质量传输是一个关键问题,本文在构建多约束OSNR模型的基础上,提出了一种基于分层图的多损伤感知MIA-RWA算法,仿真结果表明,MIA-RWA算法能获得较低的阻塞率,有效改善网络的传输质量。     

Combining verbal analysis protocol and wireless audiovisual observation to examine consumers' supermarket shopping behaviour

The study investigates the benefits of using a verbal analysis protocol combined with wireless audiovisual observation technology to collect information about consumer behaviour in real‐life environments. A sample of consumers (n = 36) were given a task to select food products in 11 different categories in a supermarket. Combining methods enabled simultaneous collection of multiple forms of qualitative and quantitative data by recording data simultaneously from different perspectives: the consumer's visual range; the wider shopping environment, to provide context; the consumer's verbalizations. Qualitative data on extrinsic and intrinsic factors that affect decision making and quantitative data on product selection time were taken as an example of rich and real‐time data obtained using the combined methods. Audiovisual material was analysed by Usability Test Software 2.0, verbal analysis data were sorted by a database programme and quantitative data were processed using SPSS 17.0. The study design provided sensitive verification of the nature of consumer interaction with the shopping environment: e.g. during the product selection time (average 23 ± 10 s/product), the interaction with the environment varied between individuals and among products selected. The approach represents a useful technique to enable the value of consumer input to direct innovation in consumer‐oriented product development. It also offers new perspectives to consumers and authorities and related organizations to understand shopping behaviour and the role of critical factors behind the food choices at the supermarket.     

Scheduling a maintenance activity and due-window assignment based on common flow allowance

We study a due-window assignment problem on a single machine. The job-dependent due-windows are obtained by the common flow allowance criterion. The scheduler has the option to perform a maintenance activity which is rate modifying, i.e., improves the processing times of the following jobs. We consider a number of versions of this setting: (i) The maintenance requires a constant time, (ii) The maintenance duration is an increasing function of its starting time (linear deterioration), and (iii) The maintenance duration is position-dependent (general deterioration). We study the standard setting of regular job processing times, and investigate also the extension to position-dependent processing times. The set of potential optimal positions for the maintenance activity is fully characterized. Consequently, the problems based on all the combinations of these settings are shown to be solved in polynomial time.     

一种高可靠性的MANET网络改进AODV路由协议

针对普通AODV路由协议存在的路由发现和路由维护巨大开销问题,提出了一种改进的AODV路由协议。仿真结果表明,改进的AODV路由协议能有效地减少路由开销和端到端传输时延,提高协议效率和可靠性。