一种多目标自动跟踪的逻辑关联方法

目标跟踪是被动声纳系统的主要功能之一,跟踪器为目标运动分析和目标识别等后置处理提供输入数据。声纳操作员利用人脑独特的认知模式、先验知识和视觉的迹迹相关效应,能够很好地在声纳显示方位历程图上发现目标并录取跟踪。但实际应用中由于低信噪比、航迹交叉和转向等复杂多目标情形,声纳系统实现多目标自动跟踪十分困难。给出一种多目标自动跟踪的逻辑关联方法,利用被动声纳宽带波束输出数据,通过点迹与航迹关联、航迹评价管理和交叉处理等过程,可以较好实现多目标自动跟踪。试验数据的处理结果验证了所提方法的有效性,能够在声纳装备中得到工程应用。     

一种基于蝙蝠算法的多目标跟踪数据关联方法

针对多目标跟踪中的数据关联问题,提出了基于蝙蝠算法的数据关联方法。首先将多目标数据关联问题建模成组合优化问题,结合数据关联的特点,对蝙蝠算法的搜索更新规则进行改进,使其可以应用于多目标的数据关联问题,并给出了基于蝙蝠算法的多目标数据关联的详细流程。通过仿真实验和被动声呐实测数据测试表明,基于蝙蝠算法的多目标数据关联方法切实可行并且具有较好的效果。     

VISA事件机制的设计与实现

虚拟仪器是一种新的仪器模式,是仪器领域的一场革命。VISA是VXI即插即用系统联盟定义的标准化的I/O接口软件,是实现虚拟仪器系统开放性和互换性的关键,而事件机制是VISA机制体系中的重要部分,包括事件捕获、通知机制和事件处理机制。本文在VISA开发工作的基础上,从事件机制的理解和事件函数的实现两个方面对VISA的开发技术进行了讨论。本文不仅较为全面的给出了对VISA的理解,而且较为全面地展示了设计开发VISA事件机制的思想和方法。     

一种支持服务扩展与重组的网络设备体系结构

针对目前网络设备中各种服务不统一的问题,基于可编程网络处理器的特点,提出了一种服务一体化的网络设备体系结构.把防火墙、VPN、负载均衡等设备对数据包的处理统一表示为一组规则与行为的集合,对数据包先统一分类,再做相应处理,从而把多种网络服务集成到一起;设计了基于Hash的分类规则表,实现了运行期更新规则表以及向数据平面载入执行代码,使功能可以动态扩展;设计了并行部署与处理网络服务的系统硬件体系结构,实现了基于IXP2400处理器的原型系统.实验证明,这种体系结构使各种服务可以方便地重组与扩展,避免了各种设备对包的重复分类,降低了网络时延,采用并行处理结构后,解决了因服务的增加而导致的性能下降的问题.     

一种无线传感器网络被动定位方法设计与实现

从无线传感器网络节点自定位出发,分析比较了无线传感器自定位的几种常见定位算法,并给出现有算法存在的问题;在嵌入GPS模块的无线传感器网络汇聚节点上提出一种新的被动定位方法,并在软硬件上得到了实现．与传统的定位方法比较,它避免了无线传感器网络必须在每个节点嵌入GPS模块的同时,能在不增加体积、成本、通信功耗的情况下提供精确的定位位置．     

一种超声波测距仪的设计与实现

针对液体、固体物体表面过于光滑,不易测量的状况,采用ATMEL公司生产的单片机AT89S52最小系统设计并实现了一种结构简单检测迅速的超声波测距仪。根据超声波在空气中的传播特性,重点讨论了超声波测距的数据处理方法、装置的硬件实现以及为提高测量精度采用的温度补偿方法。系统由单片机最小系统、温度测量电路、数码管显示电路、超声波发射接收电路、LED显示电路、报警电路组成。通过实验,表明系统测量工作可靠,有良好的测量精度和灵敏度。     

一种网络化测试系统的设计与应用

在分析研究测控网络技术的基础上．提出了一种网络化测试系统的设计方案;针对某类电子装备的检测要求,组建了某类电子装备网络化测试系统．并进行了实验室验证．结果表明．该系统采用多层复合体系结构,将客户机／服务器(C／S),浏览器／服务器(B／S)结合起来．有效降低了测试系统的整体成本,充分提高了测试系统的工作效率．     

一种写字机械臂的设计与实现

本文介绍了一种写字机械臂的设计与实现,通过大量分析、实验,将步进电机运用于写字机械臂,达到机械臂稳定书写文字的要求。基于写字机械臂的硬件和机械装置做了软件设计,找到了一种适合于本机械结构的控制算法,利用上位机与显示屏相结合提高人机交互,最后根据设计结果进行不同方面的分析,探索机械臂在实际生活中新的存在方式,以求在新的领域内机械臂的应用与技术有所突破。     

一种超声波测距装置的设计与实现

超声波测距技术应用广泛,可应用于汽车倒车、建筑施工工地以及一些工业现场的位置监控等。重点介绍了一种基于单片机的超声波测距装置的设计与实现。包括电路的基本组成及设计原理,超声波测量模块的接口特性及基本功能,软件设计原理以及测量精度的控制等。     

一种模块化温湿度巡检仪的设计与实现

基于温湿度计量工作与电子产品设计现状,设计了一种模块化温湿度巡检仪。以STC15F2K60S2单片机为控制核心,合理选择并应用软件程序将各个功能模块有效组合,并配合温度和湿度传感器,实现具有便于携带、可扩充性良好、便于调试维护与更新、性价比高等优点的温湿度巡检仪的设计。设备经过比对试验,基本达到了预期的设计目标,可以完成环境试验设备温湿度场的校准工作,并且能够较好的满足企业对环境试验设备的测量需求及其相关行业规范的要求。     

基于贝叶斯网络的计算机网络端到端服务故障诊断

研究了利用贝叶斯网络不确定推理技术实现端到端服务故障诊断的方法，详细描述了贝叶斯网络故障诊断模型的建立方法，设计了基于Pearl信念传播机制的故障诊断算法，并对其进行了改进，以提高诊断效果．最后，通过仿真验证了该方法的有效性，并提出了下一步的研究方向．     

网络性能综合评估方法IEMoNP的设计和实现

由于孤立的网络性能指标（测度）不能满足全局性或整体性网络性能评估的需要，文中给出了网络性能综合指数IPI和网络运行稳定性指数SI的概念、定义和计算公式．IPI和SI反映了相对基准时刻的网络性能状况．在此基础上，进一步提出了基于IPI和SI的网络性能综合评估方法IEMoNP．最后，通过一个应用示例表明，IEMoNP能够为全局性或整体性的网络性能评估提供支持．     

Risk-based reconfiguration of safety monitoring system using dynamic Bayesian network

To prevent an abnormal event from leading to an accident, the role of its safety monitoring system is very important. The safety monitoring system detects symptoms of an abnormal event to mitigate its effect at its early stage. As the operation time passes by, the sensor reliability decreases, which implies that the decision criteria of the safety monitoring system should be modified depending on the sensor reliability as well as the system reliability. This paper presents a framework for the decision criteria (or diagnosis logic) of the safety monitoring system. The logic can be dynamically modified based on sensor output data monitored at regular intervals to minimize the expected loss caused by two types of safety monitoring system failure events: failed-dangerous (FD) and failed-safe (FS). The former corresponds to no response under an abnormal system condition, while the latter implies a spurious activation under a normal system condition. Dynamic Bayesian network theory can be applied to modeling the entire system behavior composed of the system and its safety monitoring system. Using the estimated state probabilities, the optimal decision criterion is given to obtain the optimal diagnosis logic. An illustrative example of a three-sensor system shows the merits and characteristics of the proposed method, where the reasonable interpretation of sensor data can be obtained.     

基于OMAP平台复相关测频算法的设计与实现

高性能和小型化是水声设备的重要发展趋势,研究嵌入式Linux平台在水声设备中的应用十分有意义。TI公司开发的OMAPLl37芯片采用独特的DSP与ARM相结合的双核结构,具有集成度高、硬件稳定性强、速度快、开放性好等特点。研制了基于OMAPLl37平台的数字信号处理分机系统,并对复相关测频算法在该平台上的实现方法进行了研究。具体包括该算法的原理分析,嵌入式Linux交叉编译平台的搭建、内核的编译下载、基于ARM与DSP双核操作系统的通信方式以及算法的硬件实现方法等,最后进行了电联调实验,实验结果达到了预期的效果。对于嵌入式Linux平台在水声设备中应用有一定的参考价值。     

Reliability assessment for failure-dependent and uncertain systems: A Bayesian network based on copula method and probability-box

Managing failure dependence of complex systems with hybrid uncertainty is one of the hot problems in reliability assessment. Epistemic uncertainty is attributed to complex working environment, system structure, human factors, imperfect knowledge, etc. Probability-box has powerful characteristics for uncertainty analysis and can be effectively adopted to represent epistemic uncertainty. However, arithmetic rules on probability-box structures are mostly used among structures representing independent random variables. In most practical engineering applications, failure dependence is always introduced in system reliability analysis. Therefore, this paper proposes a developed Bayesian network combining copula method with probability-box for system reliability assessment. There are four main steps involved in the reliability computation process: marginal distribution identification and estimation, copula function selection and parameter estimation, reliability analysis of components with correlations and Bayesian forward analysis. The benefits derived from the proposed approach are used to overcome the computational limitations of n-dimensional integral operation, and the advantages of useful properties of copula function in reliability analysis of systems with correlations are adopted. To demonstrate the effectiveness of the developed Bayesian network, the proposed method is applied to a real large piston compressor.     

A method of human reliability analysis and quantification for space missions based on a Bayesian network and the cognitive reliability and error analysis method

Analyses of human reliability during manned spaceflight are crucial because human error can easily arise in the extreme environment of space and may pose a great potential risk to the mission. Although various approaches exist for human reliability analysis (HRA), all these approaches are based on human behavior on the ground. Thus, to appropriately analyze human reliability during spaceflight, this paper proposes a space‐based HRA method of quantifying the human error probability (HEP) for space missions. Instead of ground‐based performance shaping factors (PSFs), this study addresses PSFs specific to the space environment, and a corresponding evaluation system is integrated into the proposed approach to fully consider space mission characteristics. A Bayesian network is constructed based on the cognitive reliability and error analysis method (CREAM) to model these space‐based PSFs and their dependencies. By incorporating the Bayesian network, the proposed approach transforms the HEP estimation procedure into a probabilistic calculation, thereby overcoming the shortcomings of traditional HRA methods in addressing the uncertainty of the complex space environment. More importantly, by acquiring more information, the HEP estimates can be dynamically updated by means of this probabilistic calculation. By studying 2 examples and evaluating the HEPs for an International Space Station ingress procedure, the feasibility and superiority of the developed approach are validated both mathematically and in a practical scenario.     

Improvement in device performance from a mixture of a liquid crystal and photosensitive acrylic prepolymer with the photoinduced vertical alignment method

In a multicomponent nematic liquid crystal (NLC) mixture of a liquid crystal (negative-type NLC) and a photosensitive acrylic prepolymer, photopolymerization upon UV irradiation induces the separation of the LC and photosensitive acrylic prepolymer layers, thereby leading to a vertical arrangement of LC molecules. In this study, we propose a simple vertical alignment method for LC molecules, by adding a chiral smectic A (SmA∗) liquid crystal having homeotropic texture characteristics to an NLC mixture solution. Measurements of electro-optical properties revealed that the addition of the SmA∗ LC not only strengthened the anchoring force of the copolymer alignment film surface, but also significantly enhanced the contrast ratio (∼73%), response time and grayscale switching performance of the device.     

Improvement in device performance from a mixture of a liquid crystal and photosensitive acrylic prepolymer with the photoinduced vertical alignment method

Abstract

In a multicomponent nematic liquid crystal (NLC) mixture of a liquid crystal (negative-type NLC) and a photosensitive acrylic prepolymer, photopolymerization upon UV irradiation induces the separation of the LC and photosensitive acrylic prepolymer layers, thereby leading to a vertical arrangement of LC molecules. In this study, we propose a simple vertical alignment method for LC molecules, by adding a chiral smectic A (SmA?) liquid crystal having homeotropic texture characteristics to an NLC mixture solution. Measurements of electro-optical properties revealed that the addition of the SmA? LC not only strengthened the anchoring force of the copolymer alignment film surface, but also significantly enhanced the contrast ratio (～73%), response time and grayscale switching performance of the device.     

Towards Bayesian network methodology for predicting the equipment health factor of complex semiconductor systems

This paper presents a general methodology to improve risk assessment in the specific workshops of semiconductor manufacturers. We are concerned, in this case, with the problem of equipment failures and drifts. These failures are generally observed, with delay, during the product metrology phase. To improve the reactivity of the control system, we propose a predictive approach based on the Bayesian technique. Increased use of these techniques is the result of the advantages obtained. This approach allows early action to maintain, for example, the equipment before it can drift. Also, our contribution consists in proposing a generic model to predict the equipment health factor (EHF), which will define decision support strategies on preventive maintenance to avoid unscheduled equipment downtime. Following the proposed methodology, a data extraction and processing prototype is also designed to identify the real failure modes which will instantiate the Bayesian model. EHF results are decision support elements. They can be further used to improve production performance: reduced cycle time, improved yield and enhanced equipment effectiveness.     

基于散斑强度相关函数的表面粗糙度测量方法

激光经过被测表面反射和散射后,通过自由空间传播至观察面上形成散斑图像,其统计分布依赖于被测表面的微观形貌。分析此散斑图像的二阶统计特性,导出了强度变化的相关函数和表面粗糙度参数之间的关系。以表面粗糙平均值Ra分别为0.1靘, 0.2靘, 0.4靘和0.8靘的平磨标准金属样块形成的散斑图像为例,根据强度变化相关函数的离散化定义,计算得到该相关函数值。结果表明,表面越粗糙,散斑越分散,强度变化的相关函数波动越大。因此,该参数可以反映不同的粗糙面,用其作为表征表面粗糙度的特征参数,扩大了测量范围。该方法实验系统简单,对于实际测量环境要求不高,对震动不是非常敏感,适于在线测量。