YHCAPP系统工艺信息提取和工序图生成技术研究

YHCAPP系统是面向中小企业的工具型CAPP系统,如何从CAD图形提取工艺信息和生成工序图是该类系统的一个难点。文中给出了一种基于表达式求值的方法,成功解决了该难题,实际应用表明该方法稳定可靠。该方法也为一般的工具型CAPP系统提供了新思路。     

Determination of burn‐in parameters and residual life for highly reliable products

Today, many products are designed and manufactured to function for a long period of time before they fail. Determining product reliability is a great challenge to manufacturers of highly reliable products with only a relatively short period of time available for internal life testing. In particular, it may be difficult to determine optimal burn‐in parameters and characterize the residual life distribution. A promising alternative is to use data on a quality characteristic (QC) whose degradation over time can be related to product failure. Typically, product failure corresponds to the first passage time of the degradation path beyond a critical value. If degradation paths can be modeled properly, one can predict failure time and determine the life distribution without actually observing failures. In this paper, we first use a Wiener process to describe the continuous degradation path of the quality characteristic of the product. A Wiener process allows nonconstant variance and nonzero correlation among data collected at different time points. We propose a decision rule for classifying a unit as normal or weak, and give an economic model for determining the optimal termination time and other parameters of a burn‐in test. Next, we propose a method for assessing the product's lifetime distribution of the passed units. The proposed methodologies are all based only on the product's initial observed degradation data. Finally, an example of an electronic product, namely contact image scanner (CIS), is used to illustrate the proposed procedure. © 2002 Wiley Periodicals, Inc. Naval Research Logistics, 2003     

目标选择理论方法

针对现代战争特点和要求,给出了适合不同目标系统的6种打击目标选择理论,即重心效应理论、链条效应理论、瓶颈效应理论、连累效应理论、层次效应理论和组合理论。并运用这些理论,针对不同类型目标,给出了6种方法,即非线性规划方法、集合论方法、矩阵方法、群落型方法、网络型方法和塔型方法,基本涵盖了远程攻击武器目标选择理论与方法。     

用电化学方法评价油膜防锈性能

用电位—时间、多重动电位扫描两种电化学方法对防锈油的防护性能进行了分析和评价 ,并与盐水浸渍试验进行了对照。结果表明 :两种电化学方法不仅与盐水浸渍试验具有良好的相关性 ,而且能够反映油膜下金属腐蚀的细微特征 ,是研究和评价防锈油较好的方法     

Deterministic inventory lot‐size models under inflation with shortages and deterioration for fluctuating demand

In this paper, we extend the inventory lot‐size models to allow for inflation and fluctuating demand (which is more general than constant, increasing, decreasing, and log‐concave demand patterns). We prove that the optimal replenishment schedule not only exists but is also unique. Furthermore, we show that the total cost associated with the inventory system is a convex function of the number of replenishments. Hence, the search for the optimal number of replenishments is simplified to finding a local minimum. Finally, several numerical examples are provided to illustrate the results. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 144–158, 2001     

科索沃战争中攻防对抗的几点分析

科索沃战争是一场交战双方实力悬殊的战争。拥有高技术兵器的北约军队对主权国家南斯拉夫实施了高精度、远毁伤、非接触的空袭,而处于弱方的南联盟军民,寻找对方弱点,采取灵活战术进行反空袭作战,使北约集团也付出了很大的代价。这场战争是现代高技术条件下的一场典型的进攻与防御对抗作战,它反映了以落后技术装备遏制拥有高技术之敌进攻的特点和规律。     

用于DDR3访存优化的数据缓冲机制

为提高DDR3控制器访存效率,设计了基于DDR3存储器预取访问数据长度的数据缓冲机制,将访存请求分为三种基本类型并分别排队处理,降低数据丢弃和实际动态随机访问存储器访问发生次数。针对图像和视频类应用程序的实验结果表明,相对于传统先到先服务的DDR3访存控制器,该机制取得了平均21.3%、最好51.3%的性能提升,硬件开销在可接受范围内。     

PTFE润滑剂的研制

介绍了PTFE润滑剂的研制过程、配方、制备工艺和应用效果。结果表明以PAO合成油和矿物油的混合油为基础油,以PTFE超细粉为润滑组分,通过加入多种添加剂研制的PTFE润滑剂具有胶体稳定性、分散性、润滑性和防护性。     

基于DWK海洋作战建模与仿真

直接基于HLA/RTI进行分布式仿真系统开发,存在对用户开发经验要求较高的问题,针对这种不足,提出了一种基于DWK(数字化武器开发平台)快速构建海洋作战仿真系统的方法.在简述DWK功能结构的基础上,解决了系统结构设计、实体建模、FOM开发、兵力模型和HLA模型研究、联邦成员开发等多项关键技术,系统的开发过程证明了该方法...     

基于机动识别的多级组合滤波器设计

针对机动目标滤波问题,利用基础的琢-茁滤波算法,建立了基于机动识别的多级组合琢-茁滤波算法.从工程可实现角度出发,重点阐述了组合滤波器的机动识别算法、野值剔除算法、机动识别与野值剔除启动算法,以及多级滤波器的切换规则.仿真结果验证了组合滤波算法的有效性.