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本文介绍了GIS技术在组合式定位定向系统中的应用,阐述了采用Maplnfo软件平台和Visual C 实现电子地图系统控制软件的设计与开发,探讨了使用OLE自动化技术将Maplnfo矢量地图调入系统应用程序的方法。 相似文献
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对基于掌上电脑的嵌入式电子地图系统中查询优化问题进行研究,构造基于掌上电脑平台环境下多尺度数字地图的数据模型,建立一种适用于嵌入式GIS系统的四叉树空间索引,以提高空间查询的效率;提出了一种优化嵌入式GIS系统中的数据访问方法.系统应用结果表明:改进的四叉树可提高空间查询的效率,数据优化方法可加快电子地图显示和查询的速度. 相似文献
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为满足固体火箭发动机设计过程对集成的需求,开发了一个基于WEB的发动机集成设计平台,提出了采用J2EE技术构建基于WEB的集成设计平台方案,建立了集成设计平台体系结构,分析了体系结构中每一层内涵,重点对集成平台功能框架层进行了详细分析,给出了基于J2EE的平台软件实现方案。平台实现了发动机设计过程中应用集成、信息集成和过程集成,能够支持优化设计和分布式设计人员的协同工作。通过在某翼柱型装药固体火箭发动机设计中的应用实例表明,该平台能够有效提高设计效率和质量,显著缩短设计周期。 相似文献
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电子地图是民机试飞中常见的监控应用,用于实时反映试飞飞机的位置、航迹和空域等信息。但传统的电子地图功能单一,存在无法动态更新空域、不能航后回放以及不支持多架机集中监控等问题,无法满足当前试飞安全监控需求。基于GMAP.NET组件设计研发了一款新的二维电子地图实时监控软件,采用多线程调度、动态图层等技术,集成了时序数据库,在实现多架机试飞航迹实时监控的同时,支持航迹信息的实时存储、回放和空域信息的在线更新。通过在某国产大型客机试飞现场的测试,软件可满足试飞航迹的安全监控需求。 相似文献
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Servicing is applied periodically in practice with the aim of restoring the system state and prolonging the lifetime. It is generally seen as an imperfect maintenance action which has a chief influence on the maintenance strategy. In order to model the maintenance effect of servicing, this study analyzes the deterioration characteristics of system under scheduled servicing. And then the deterioration model is established from the failure mechanism by compound Poisson process. On the basis of the system damage value and failure mechanism, the failure rate refresh factor is proposed to describe the maintenance effect of servicing. A maintenance strategy is developed which combines the benefits of scheduled servicing and preventive maintenance. Then the optimization model is given to determine the optimal servicing period and preventive maintenance time, with an objective to minimize the system expected life-cycle cost per unit time and a constraint on system survival probability for the duration of mission time. Subject to mission time, it can control the ability of accomplishing the mission at any time so as to ensure the high dependability. An example of water pump rotor relating to scheduled servicing is introduced to illustrate the failure rate refresh factor and the proposed maintenance strategy. Compared with traditional methods, the numerical results show that the failure rate refresh factor can describe the maintenance effect of servicing more intuitively and objectively. It also demonstrates that this maintenance strategy can prolong the lifetime, reduce the total lifetime maintenance cost and guarantee the dependability of system. 相似文献
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Monarchie D. Budzilek R. Cupero F. 《Aerospace and Electronic Systems Magazine, IEEE》1995,10(8):21-25
A new advanced type of high ambient viewing AC electroluminescent display has been developed incorporating a combination of high contrast and high brightness techniques. The improvement in the contrast is achieved by a black absorption layer within the thin film structure. Improvement in the brightness is attributed to increasing the refresh rate by an order of magnitude. This can only be accomplished by an order of magnitude decrease in front electrode impedance with the use of a new metalized structure to reinforce the ITO electrodes and lower their resistance 相似文献
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计算机病毒是危害计算机系统安全的主要因素,本提出了几种可行的病毒防范措施及在遭受病毒破坏后系统恢复办法。 相似文献
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基于新形势下维修现场信息化需要,结合维修厂工作实际,介绍了基于,NET的飞机维修现场控制系统的设计与实现,广泛应用AJAX技术实现页面局部刷新,创新了技术应用,推动了业务创新与转型。 相似文献
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The ATE industry can benefit greatly by becoming better informed about the availability, functionality, and reliability of emulated peripheral solutions. Emulated peripherals provide the ability to dramatically extend the life of aging ATE equipment, while making that equipment more reliable, more functional, much easier to use, and much simpler to support. The use of emulated disk drives and tape drives can completely eliminate persistent maintenance headaches, increase ATE station availability and reliability, and provide a reasonably priced technology refresh without costly software modifications or system recertification. 相似文献
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Littlejohn K. DelPrincipe M.V. Preston J.D. 《Aerospace and Electronic Systems Magazine, IEEE》2000,15(11):3-7
Currently fielded embedded information systems face readiness challenges imposed by evolving missions and extended service lifespans. The ability to overcome these challenges is constrained by such factors as shrinking budgets, limited computational capacity and diminished manufacturing sources effects that impact both hardware and software options. Wholesale redevelopment is often cost prohibitive, particularly since large portions of embedded applications continue to fulfil mission requirements. Solutions must preserve prior investments while providing efficient pathways for continued technology refresh. A technology solution for affordable modernization of legacy system software is being development. The Embedded Information System Re-engineering (EISR) project is developing an automation-assisted JOVIAL-to-C re-engineering capability that permits simultaneous modernization of both the structure and source language of legacy embedded applications. Engineers will be able to apply the proven labor-saving visualization and analysis features of modern CASE tools to legacy JOVIAL applications. EISR will thus allow the DoD to recapture previous investments in proven legacy algorithms and mission capabilities while permitting the full exploitation of COTS economies of scale. This paper describes in brief the goals and objectives of the EISR project, and provides the current status of the EISR capability. 相似文献
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Complex Flow for Wing-in-ground Effect Craft with Power Augmented Ram Engine in Cruise 总被引:2,自引:1,他引:1
Power augmented ram (PAR) engine is a popular equipment to reduce the requirement of power for takeoff and improve aerodynamic performance. To provide detailed insight into the aerodynamic characteristics of wing-in-ground effect (WIG) craft with PAR engine, numerical simulations are carried out on WIG craft models in cruise. Simplified engine models are applied to the simulations. Two cruise modes for PAR engine are considered. The aerodynamic characteristics of the WIG craft and other features are studied. Comparisons with WIG craft model without PAR show that shutoff of PAR engine results in an increase in drag and less change in lift. Accordingly for the work of PAR engine, the air flow blown from the engine accelerates the flow around the upper surface and a high-speed attached flow near the trailing edge is recorded. With the schemed PAR flow, more suction force is realized and the flow features over the wing vary noticeably. It is also shown that the Coanda effect, provided with an attached flow, introduces an appropriate and practical flow mode for WIG craft with PAR engine in cruise. The results refresh our understanding on aerodynamic characteristics of WIG craft. 相似文献
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不同管制方法下空域运行的燃油经济性与仿真分析 总被引:1,自引:0,他引:1
为了提高空域运行的燃油经济性,提出了不同管制方案下空域运行的燃油经济性模型,通过仿真实验.对比分析了不同管制方案和飞机群体在空域运行的燃油消耗量。实验结果表明:通过使用该模型可以从管制方法上节省整体空域中飞机群体的燃油消耗,同时证明了该模型的可行性。指出了不同管制方法对空域运行的燃油经济性的影响和空管绩效评估的一项新指标。 相似文献