Optimizing specimen collection for processing in clinical testing laboratories

We study the logistics of specimen collection for a clinical testing laboratory that serves sites dispersed in an urban area. The specimens that accumulate at the customer sites throughout the working day are transported to the laboratory for processing. The problem is to construct and schedule a series of tours to collect the accumulated specimens from the sites throughout the day. Two hierarchical objectives are considered: (i) maximizing the amount of specimens processed by the next morning, and (ii) minimizing the daily transportation cost. We show that the problem is NP-hard and formulate a linear Mixed Integer Programming (MIP) model to solve the bicriteria problem in two levels. We characterize properties of optimal solutions and develop a heuristic approach based on solving the MIP model with additional constraints that seeks for feasible solutions with specific characteristics. To evaluate the performance of this approach, we provide an upper bounding scheme on the daily processed amount, and develop two relaxed MIP models to generate lower bounds on the daily transportation cost. The effectiveness of the proposed solution approach is evaluated using realistic problem instances. Insights on key problem parameters and their effects on the solutions are extracted by further experiments.     

Selfish routing in public services

It is well observed that individual behaviour can have an effect on the efficiency of queueing systems. The impact of this behaviour on the economic efficiency of public services is considered in this paper where we present results concerning the congestion related implications of decisions made by individuals when choosing between facilities. The work presented has important managerial implications at a public policy level when considering the effect of allowing individuals to choose between providers. We show that in general the introduction of choice in an already inefficient system will not have a negative effect. Introducing choice in a system that copes with demand will have a negative effect.     

光突发交换网络中的区分服务研究

为了在光突发交换网络中提供端到端的区分服务,提出了一种区分服务模型,并详细介绍了其功能.提出了一种控制分组的区分服务编码点,详细研究了一系列区分服务规则,包括编码点的改写和更新以及区分服务模型的可扩展性.同时提出了几个有待进一步研究的问题.     

综合结算系统及其工程应用

本文介绍了综合电信业务结算系统建设的背景、目标、系统功能及体系结构,并以辽宁联通为例阐述综合结算系统在工程建设中的实际应用.     

基于PPV的公平移动支付协议

结合CEMBS的设计思想,在尽量满足移动网络特性的情况下,设计了一个能在移动终端观看视频服务的即看即付的公平协议.该协议在服务请求阶段通过利用CEMBS,在乐观情况下,可信第三方移动网络运营商不需参与,就可使互不信任的User与VASP完美地实现双方的认证与会话密钥协商,同时完成了服务请求的建立,双方均是不可否认的,且整个过程只需三条消息;在支付阶段,也可以保证双方公平地进行交易.通过分析,该协议满足公平性、不可否认、原子性、认证性以及保密性等一些必备性质,且协议比较简单,应用范围比较广泛.     

Web Services应用于电力GIS的探讨

近几年GIS在电力系统得到了广泛的应用。Web Services的出现,将改变在Web上进行软件设计的方法,也将引起电力GIS体系的变革。通过对电力GIS单个事例的剖析,给出一个基于Web Services的WebGIS三层系统构架模型并进行论述。基于Web Services开发的电力GIS具有系统扩展性强、代码重用度高的特点。其同时也是解决目前WebGIS系统所面临的问题的有效途径。     

石油企业信息系统互操作通信模型的构建

随着石油企业信息化进程进一步加快,各个业务系统数据库异构性问题越来越突出。如何有效地利用这些历史数据,集成遗留系统,成为目前集成领域的一大热点。在分析Web服务体系结构的基础上,提出以石油企业信息化标准作为解决互操作的信息模型,基于Web服务技术构建适合石油系统数据资源共享与交互的通信模型,并设计通信模型的数据交互机制。实践表明,它能够较好地满足信息模型与通信模型间的松散耦合要求,较好地实现异构数据源统一透明访问,保证数据完整性、安全性和一致性,并且具有较高的开发效率。     

集团移动信息化多业务综合接入系统的规划和设计

集团移动信息化增值业务具有巨大的市场潜力,而且能够最大限度地利用各移动运营商现有的移动网络优势,是各移动运营商未来集团客户业务收入的重要增长点.文章就集团移动信息化多业务综合接入系统进行了深入地研究,并提出了今后集团移动信息化多业务综合接入系统的规划和设计方案.     

Coordination of wavelength and time-window assignment in WDM-based TDM hybrid-PONs

In passive optical networks (PONs), the low effectiveness in terms of service utilization and network evolution have been important design issues. In this article, we introduce a hybrid access network architecture, so called scalable WDM-based Ethernet hybrid-PON (SWE-PON), which features a wavelength-division-multiplexed (WDM) feeder network using a combination of tunable laser device (TLD) and cyclic arrayed waveguide grating (AWG) and time-division-multiplexed (TDM) distribution network based on a reflective transmission mode. Necessary conditions needed to guarantee flawless packet transmission through normal WDM/TDM hierarchical PONs including the SWE-PON, are analyzed. We also propose a hierarchical fair time-window allocation mechanism which coordinates wavelength assignment and time-window bandwidth allocation so that high link utilization and fair bandwidth allocation are guaranteed in every multiplexing level.

从国办发[2008]1号文件看广电有线网络改造的紧迫性

从国办发[2008]1号文件的出台,论述广电有线电视网络双向化改造的紧迫性,以及有线电视网络双向化改造采用技术方案的选择建议。