交互式电子技术手册在舰船装备信息化保障中的应用

舰船装备的信息化保障是部队战斗力的重要因素之一。传统的装备维修保障方式已无法满足部队信息化建设的要求,通过交互式电子技术的运用,建立实时交互的舰船装备管理平台,可提高装备维修保障信息化管理的水平和效率。针对舰船装备发展趋势及维修管理的要求,采用VB软件和Access数据库编制了某型舰船装备交互式电子技术手册。通过该手册,可方便快捷地浏览、查询、添加和删除设备的三维模型、工程图、故障案例和维修标准等信息。手册的应用极大的促进了舰船装备的信息化管理水平,具有广阔的应用前景。     

大型ORACLE数据库系统的优化设计方案

ORACLE数据库技术在各类船舶管理系统中应用广泛,提供综合的船舶管理、人事管理、设备管理、交易管理、保养管理以及故障查询分析等各种业务应用,以保障船舶行驶安全,降低事故发生率、提高企业管理水平、提高服务水平、加强管理力度、增加管理效率,减少人力、物力、财力上的浪费.本文主要从大型数据库ORACLE环境4个不同级别(操作系统级包括硬件平台、ORACLE关系管理系统级、数据库系统设计级、数据库开发范畴的结构化查询语句分析级)的调整分析入手,分析ORACLE的系统结构和数据存取工作机理,从9个方面分析ORACLE数据库的优化调整方案.     

浙江省公路网车辆OD数据库管理系统开发研究

基于公路网OD调查数据现状管理与深度利用的需要,结合浙江省公路网车辆OD数据库管理系统的开发．对系统设计原则与开发平台、功能与框架、技术流程以及关键技术进行详细阐述,可为今后建立更科学和完善的数据库系统提供参考。     

基于数据挖掘的客运营销与优化系统分析

用数据挖掘技术对我国铁路客运信息进行分析和处理,从而促进铁路客运市场营销策略的灵活调整,并根据分析结果对客运营销旅客列车在开行方案上进行优化,这有利于铁路客运主管部门的管理和决策,为铁路客运争取更大的经济效益和社会效益。     

高校图书馆航海类专业特色数据库调查分析

通过网络和电话访问，对国内17所本科高校图书馆航海类专业特色数据库的建设情况进行了调查，从数量、类型和内容进行了归类和分析。指出目前各校航海类专业特色数据建设存在的主要问题，从提高建设质量、提高资源利用率、走可持续发展之路3个方面，对高校图书馆航海类专业特色数据的建设提出了明确的对策和建议。     

桥梁工程设计数据库管理系统的研究

基于关系数据库理论的观点，结合工程的实际需要，研究开发了“桥梁工程设计数据库管理系统”。本文讨论了系统分析、数据模型选择、系统的总体设计、一般应用模块、高级应用模块以及系统软件实现等有关的技术问题。     

AJAX技术在Struts验证框架中的应用研究

Ajax是当前流行的一种适用于Web应用开发中的技术，它可以实现无需刷新整个页面，就可以动态更新页面中一部分的内容本文。在介绍Ajax技术和Struts验证框架的基础上，提出了将Ajax技术运用于Struts验证框架中进行数据验证的方法。Struts验证框架通过加入Ajax技术，使得Web应用程序的运行效果更接近于桌面应用程序。     

The impacts of changing flight demands and throughput performance on airport delays through the Great Recession

Several significant events between 2007 and 2009 impacted flight demands and the abilities of the three major New York area airports to handle demand. This paper assesses the results of applying a probabilistic simulation method – which isolates the individual contributions of changes in flight demand and changes in airport throughput performance to changes in flight delays – to diagnose how these different events may have caused operational changes at these airports, and in turn, how the results may be used to inform policies for appropriate countermeasures. The analysis revealed two key observations. Firstly, certain patterns in throughput performance shifts caused the most significant delays, and were more likely to have been caused by controller staffing issues rather than caps. Secondly, relatively constant average delays from one year to the next may result from significant demand drops accompanied by large throughput performance degradations at an airport. This suggests that not only operational limitations on capacity encourage airlines to reduce schedules, but that changed demands can also impact throughput performance. Overall, the analysis indicates that caps may not have provided their fully intended delay benefits. Although they successfully reduced overall flight demands at LGA and JFK, they also directly limited throughput performance at critical times, in turn limiting delay benefits. In addition, demands at the busiest times of the day appear to be relatively inelastic to these operational limitations, insofar as demand profiles at EWR and JFK remained “peaky” in 2008 and 2009. Also, the recession was largely responsible for reducing demands at the airports in 2009, but the delay benefits of this were dampened by a corresponding throughput performance degradation. Based on the above observations, a more direct demand management policy combined with policies that focus on maintaining high staffing capabilities at critical times of the day may be considered, to reduce the likelihood of major queue formation on days that do experience sustained demands. The results also suggest that a more flexible caps system, particularly during times of heavy queues, could be explored. Although airport practitioners have keen understandings of how their airports operate, without the support of quantitative analysis tools, it can be more difficult to argue the need for appropriate countermeasures. An analysis such as the one presented here can provide the detailed quantitative substantiation required to build cases for these targeted policy directives and infrastructure investments.     

系统效能通用评估工具研究

基于数据库和算法集成,设计了一套具有良好通用性、灵活性、可扩展性的系统效能评估工具,并以此工具为基础,针对不同的评估需求、数据量和应用环境提出对应的解决方案.     

Numerical and experimental analysis of bow flare slamming on a Ro–Ro vessel in regular oblique waves

A method for the prediction of slamming loads on ship hulls is presented and validated for a 20-knot, 120-m car carrier. A nonlinear strip theory is used to calculate the relative motions of ship and wave. The relative vertical and roll velocities for a slamming event are given as input to the slamming calculation program, which is based on a generalized two-dimensional Wagner formulation and solved by the boundary element method. The method is fast and robust. Model tests of a car carrier have been carried out in regular head, bow, and bow quartering waves of various heights. Slamming on two panels in the upper part of the bow flare has been studied. It has been found that the water pile-up around the bow due to the forward speed of the vessel significantly increases the slamming pressures. A simplified way of including this effect is presented. When the calculated slamming pressures are corrected for 3D effects, they compare well with the measured data. Since the effect of the wave elevation due to the forward speed and the effect of three-dimensional flow act in opposite directions, excluding both of them produced results that also agreed quite well with the experiments, especially for the most severe slamming events.