Taxonomic performance evaluation for multitarget tracking systems

A scoring scheme based on an object track classification which facilitates performance evaluation for multiple-target tracking systems is derived and applied to specific test cases involving a comparison of operational and modified tracking system performance. The performance measures derived can be applied both to comparative evaluations of tracking system alternatives where relative performance is the issue, and to evaluations of system performance relative to what can be achieved in any given target object environment     

Certification of production-representative/productionsoftware-intensive systems for dedicated test and evaluation

Fundamental questions that arise in the certification of readiness for dedicated test and evaluation of software-intensive systems are addressed. They concern what comprises production-representative or production software, what are the software impacts on dedicated system operational test readiness, how software impacts should be considered in the certification process, and what are the retest/recertification requirements associated with software changes/modifications. A paradigm is proposed that answers these questions and outlines guidelines for implementing a solution to these issues. The paradigm is based on existing test and evaluation events and uses a combination of defense and commercial standards and definitions to propose criteria for software certification and retest or regression test     

Status analysis on sputtering and erosion evaluation methods of ion optic systems

In the past few decades, ion engines have been widely used in deep-space propulsion and satellite station-keeping. The aim of extending the thruster lifetime is still one of the most important parts during the design stage of ion engine. As one of the core components of ion engine, the grid assembly of ion optic systems may experience long-term ion sputtering in extreme electro-thermal environments, which will eventually lead to its structural and electron-backstreaming failures. In this paper, the current studies of the grid assembly erosion process are systematically analyzed from the aspects of sputtering damage process of grid materials, numerical simulations, and measurements of erosion characteristics of grid assembly. The advantages and disadvantages of various erosion prediction models are highlighted, and the key factors and processes affecting the prediction accuracy of grid assembly erosion patterns are analyzed. Three different types of experimental methods of grid assembly erosion patterns are compared. The analysis in this paper is of great importance for selecting the sputter-resistant grid materials, as well as establishing the erosion models and measurement methods to accurately determine the erosion rate and failure modes of grid assembly. Consequently, the working conditions and structure parameters of ion optic systems could be optimized based on erosion models to promote the ion engine lifetime.     

A critical evaluation of two Reissner–Mindlin type models for composite laminated plates

The purpose of this paper is to critically evaluate two Reissner–Mindlin type theories developed recently for composite laminated plates, namely, VAPAS (Variational Asymptotic Plate And Shell analysis) and EFSDT (Enhanced First-Order Shear-Deformation Theory). The fundamentals of both models are briefly summarized along with their unique features in comparison to most other existing models. The similarities and differences between VAPAS and EFSDT are also examined. Exact solutions of three-dimensional elasticity theory for the cylindrical bending problems are used as the arbiter to assess the accuracy of both models. Such a systematic assessment demonstrates that both models have achieved an excellent compromise between the layer-wise theories, which are accurate but computationally demanding, and the first-order shear deformation theories, which are computationally cheap but not accurate.     

纳米复合镀层工艺及性能研究

分析了含Al_2O_3、SiO_2和ZrO_2纳米粒子的镍基电刷镀复合镀层的组织、显微硬度、耐高温性能及耐磨性。结果表明,含有纳米粒子的复合镀层组织明显细化。随着纳米粒子含量的增加,复合镀层的硬度显著提高,高温硬度和耐磨性也有明显的增加。不同性质的纳米粒子的强化效果有所不同。     

论实验室模具的技术改造

通过分析现有的实验条件，提出并论述了实验室模具技术改造的必要性，阐述了模具技术改造的方案，以及模具改造方案的具体实施过程。     

数控铣削加工的工艺分析

从选择并确定数控加工部位及工序等方面对数控铣削加工工艺进行了分析,并提出了所要解决的主要问题及措施,对做好数控铣削加工编程工作有着一定的参考作用。     

民用航空技术的新发展

经过近一个世纪的发展,航空工业已进入信息技术新时代,航空科学技术除了将继续追求高效率、更安全和对环境保护更有利外,一个重大的改变就是摽陕虻闷饠,也就是任何新技术必须使用户在经济上承受得了.不仅商用航空是如此,军用航空也是如此.现在的每一个新研制计划在招标时都把摽陕虻闷饠作为确保各种技术指标的前提.     

Technological Research on Milling of Quench Steel

通过对45号、30CrMnSiA为主的淬火钢(硬度HRC35-50)铣削加工的研究,分析了淬火钢铣削过程中各影响因素,优化了切削参数,确定了适合加工淬火钢的刀具几何参数及材料,明确硬质合金刀具加工淬火钢时,应该采用油雾冷却,为以后的淬火钢铣削加工提供依据和指导.     

航空树脂基复合材料技术发展

通过介绍我国航空树脂基复合材料的发展现状和应用情况,讨论并分析了航空树脂基复合材料未来的发展趋势和重点方向,强调了这种“低成本”、“工程化”技术应在“一体化”思想指导下综合协调发展。     

数字图书馆建设之技术体系分析

进行数字图书馆建设是21世纪图书馆迎接网络时代的重要战略,从建设数字图书馆需要解决的技术问题和应该采用的技术体系,及在技术体系中相关应用系统的开发方面谈了数字图书馆的建设途径.     

战场抢修技术面临的挑战与机遇

战伤抢修就是在一个合理的战术时间内,使受到损伤的武器系恢复战斗能力所进行的修理.     

科技论文的投稿策略

目的为作者的科技论文写作和成功投稿提供借鉴和帮助；方法以编辑的视角多方面解读影响科技论文投稿命中率的因素；结果从了解并选择所投刊物，撰写科技论文应有的几个注重，投稿时若干注意事项和策略等三方面分析了科技论文的投稿策略；结论论文投稿有技巧和策略可循，但是作者真正应下工夫的地方，不是囿于方法，也不是囿于投稿策略和人际关系，而是要多参加科研实践，掌握素材，勤于笔耕，保证论文的学术价值。     

基于IP的网络管理技术分析

对基于IP的网络管理采用的技术,如基于策略的网络管理,RMON技术,基于Web的网络管理技术和结构化网络管理的实现要点进行了介绍,并对这几种网络管理技术的优点进行了分析。     

关于发动机高压涡轮叶片修理

<正>在航空发动机中,高压涡轮叶片无疑是最复杂的单部件之一。从设计上看,高压涡轮叶片的叶形是按照气动效率设计的,而且内部有复杂的多子孔层板冷却通道,但为了防止其腐蚀和超高温变形,最终仍需在设计好的叶形上覆盖多层涂层。尽管在设计和制造过程中考虑了各种保护,但叶片的尖部仍会经常与叶冠或罩环相摩擦,致使叶片尖部磨损、腐蚀或出现细小裂纹。即使是热障涂层,也会遭受热循环、极端温度和腐蚀,甚至可能会出现     

航空发动机制造工艺仿真技术体系探索

基于航空发动机仿真工作发展规划,从制造维度对仿真技术的应用需求进行了深入分析。提出了构建航空发动机制造工艺仿真技术体系的思路和建设原则,基于5个环节的应用需求提出了仿真技术体系的初步框架,并对当前需要加快突破的仿真关键技术进行了分析,推进航空发动机制造工艺仿真技术发展和规划的落地。     

污染土壤原位生物修复技术进展

原位生物修复在治理污染土壤中的作用日益突出，因而对于原住生物修复的研究愈加受到重视。文中针对原位生物修复的发展情况分别就生物修复实例和实验室研究进展进行了综述。     

分布式创新中技术知识整合框架研究

基于演化、资源和知识的视角,提供了分布式创新中技术开发背景下技术知识整合的分析框架。从三个视角研究分布式创新要素,阐述了知识、知识转移和执行之间的结构关系,为企业整合知识资源,提高分布式创新能力提供借鉴和指导。     

摩托车发动机机加柔性生产线工艺设计

技术改造实施成功与否,很大程度取决于该项目的工艺设计水平。本文从柔性生产线工艺设计依据、指导思想、主要设计内容,以及生产线总体技术水平和经验教训等方面,较详细地介绍了摩托车发动机机加柔性生产线工艺设计的全过程。     

科技档案质量分析与全面质量管理

旨在提高和保证科技档案质量,以满足科学技术继承和发展的需要。包括科技档案的定性研究、定量分析和全面质量管理三部分内容。第一部分深刻剖释了科技档案的质量特性,建立了科技档案质量标准指标体系,提出了评定科技档案质量的途径;第二部分论述了科技档案定量分析的集合比较、模糊评价和层次分析三种方法,这是科技档案学研究的一个重大突破;第三部分简述了科技档案全面质量管理的方法步骤和质量保证体系。