CORBA构件实现框架研究

构件技术已经发展成为软件复用的主流技术,CORBA构件模型是一种全新的服务器端构件模型,它鼓励通过构件组装来搭建应用系统,从而简化了CORBA应用程序的开发过程,提高了软件生产率和复用程度。该文在CORBA构件模型规范的基础上给出了一个实现框架,详细讨论了在该框架下CORBA构件的实现过程。     

Application of centralised DEA approach to capital budgeting in Spanish ports

In this paper, we propose a number of non-radial, output-oriented, centralised DEA models to determine individual and collective output target levels, input slacks and input reallocations as well as additional inputs acquisitions under a capital budget constraint. The application of the proposed approach to the Spanish Port Agency is presented. The overall amount of inefficiency currently found in the system allows for the determination of potential total output increases ranging from 24% to 114% without additional resources. Considering inputs reallocation would allow for an additional 20% output expansion. The acquisition of additional input resources would make feasible to expand outputs further, to levels whose exact values monotonously depend on the capital budget considered.     

Concurrent communication and synchronization mechanisms

The concepts of process and guarded command have become the basic building blocks in concurrent programming language design. In this paper we deal with many of the proposed communication and synchronization primitives and we compare them from the perspective of their implementability. Our evaluation treats four basic criteria: the length of synchronization, process termination, deadlock and protocol complexity.     

Concurrent Pascal with backward error recovery: Language features and examples

The programming language Concurrent Pascal has been extended to include some language features that facilitate the writing of fault-tolerant software. As a result, it is possible now to (1) write operating systems with a measure of fault-tolerance, and (2) for such an operating system to support fault-tolerant user programs. The paper describes these language features and illustrates their use with the help of a few working examples.     

A quantitative risk analysis approach to port hydrocarbon logistics

A method is presented that allows quantitative risk analysis to be performed on marine hydrocarbon terminals sited in ports. A significant gap was identified in the technical literature on QRA for the handling of hazardous materials in harbours published prior to this work. The analysis is extended to tanker navigation through port waters and loading and unloading facilities. The steps of the method are discussed, beginning with data collecting. As to accident scenario identification, an approach is proposed that takes into account minor and massive spills due to loading arm failures and tank rupture. Frequency estimation is thoroughly reviewed and a shortcut approach is proposed for frequency calculation. This allows for the two-fold possibility of a tanker colliding/grounding at/near the berth or while navigating to/from the berth. A number of probability data defining the possibility of a cargo spill after an external impact on a tanker are discussed. As to consequence and vulnerability estimates, a scheme is proposed for the use of ratios between the numbers of fatal victims, injured and evacuated people. Finally, an example application is given, based on a pilot study conducted in the Port of Barcelona, where the method was tested.     

用并口实现D/A转换器的快速测试

本文简要介绍了D/A转换原理及D/A转换器快速测试的虚拟仪器实现方案,并给出了部分关键源程序.     

Port capital formation and economic development in Japan: A vector autoregression approach

Applying the lag-augmented vector autoregression approach developed by Toda and Yamamoto (1995), we analyse the causal relationships among GDP, private capital, transport user cost, and port capital in Japan, and investigates the dynamic and accumulated effects of port capital formation on other variables from 1966 to 1997. Results from our analysis indicate that the causal relationships between port capital and other variables are significant. Port capital development leads to accrual of considerable magnitudes of both flow and stock effects. We conclude that structural economic effects of forming port capital are substantial for Japan.Received: 10 September 2002, Accepted: 14 August 2003, JEL Classification: C32, E22, F10, O47, R42We express our gratitude to the Ports and Harbors Bureau of Japans Ministry of Land, Infrastructure and Transport for providing us with valuable data. We also thank the Pacific editor and anonymous referees for useful comments.     

开放式数字图书馆的Handle System实现机制

该文研究了数字图书馆(Digitallibrary)及其涉及的关键技术。首先分析了该领域的研究状况,研究其中存在的问题,指出了在实施中建立数字图书馆服务模型的必要性,从而分析定义了数字化图书馆的HandleSystem服务模型,并着重提出了数字化图书馆的HandleSystem服务系统实现机制及其核心技术。最后,通过原型系统实现和验证了其可行性与有效性。     

使用UDP协议实现大文件的点到点传输

提出了一种使用UDP协议和动态数组进行大文件传输的方法，并对大文件点到点传输时端口的自动设置问题予以了说明。     

对气缸盖基本拓扑结构及其气道的参数特性研究

利用参数研究方法,对大功率柴油机气缸盖的基本拓扑结构及其气道的参数特性进行了研究,获得了在纯机械负荷下,气缸盖的底板、顶板、中隔板、缸体丝对立墙、进排气道以及进排气侧壁的总体厚度变化对气缸盖整体应力水平的影响规律。