源数据错误引起的障碍分析

在ＡＬＣＡＴＥＬＧＳＭ交换机中 ,号码分析字冠是以树的结构分类 ,所有的字冠分为５棵树 ,其中ＴＲＥＥ１是手机做主叫的分析字冠 ,ＴＲＥＥ２是短消息中心的分析字冠 ,ＴＲＥＥ７是ＰＳＴＮ呼入的分析字冠 ,ＴＲＥＥ５和ＴＲＥＥ６分别为漫游、呼叫前转字冠以及ＭＳＣ呼入字冠。从数据的角度来看 ,用户进行呼叫处理的流程如图１所示。当一呼叫源发起一个呼叫时 ,呼叫处理软件先搜寻其源码信息 ,并确定在哪一棵数字树上分析所送的号码 ,然后在该数字树上分析呼叫源送来的字冠 ,从中获得目标信息 ,再将源信息与目标信息综合起来进行分析 ,用…     

某线绕电位器失效分析及改进

某产品在进行振动应力筛选时,出现了测角输出动故障。通过对故障及产品原理的分析,确认了产品失效的机理。并对具体故障器件线绕电位器进行了失效分析,找出了测角输出故障的主要原因,即该线绕电位器内部接线方式和锡铅焊料选择不当所致。通过改进线绕电位器引线接线方式以及改变电位器内部钎料,提高了线绕电位器的可靠性,有效控制类似故障的再次发生。     

485总线协议处理器的失效分析研究

集成电路在实际应用中,经常会出现工作异常甚至失效的情况。当电路发生失效时,需要采用各种手段尽快定位问题所在,随后在本地复现相关现象,明确问题原因,进而提出针对性的解决方案。文章介绍了一款485总线协议处理器电路的失效分析过程,包括问题的出现、现场确认、失效现象复现以及测试分析和问题解决等内容,对于相关集成电路的失效分析具有一定的参考价值和借鉴意义。     

MEMS麦克风的失效机理及失效分析

MEMS麦克风是将音频信号转换成电信号的微型传感器,其工作过程涉及到声学、机械学和微电子学等学科。随着MEMS麦克风封装尺寸的不断缩小和声学性能的不断提升,以电学测试结果作为失效分析出发点的传统半导体失效分析方法越来越难以满足MEMS麦克风失效分析的需要。针对MEMS麦克风独特的封装结构和工作原理,其失效分析方法主要包括声学性能测试、机械性能测试和电学性能测试,并结合传统的半导体物理失效分析手段来找到真正的失效原因及失效机理。     

无失效数据可靠性分析的贝叶斯方法

Bayes方法是对无失效数据问题进行可靠性分析的有效途径之一。针对某一产品,在确定了其寿命分布类型之后,建立了无失效数据模型,并利用Bayes方法对产品进行了可靠性分析。     

SiP组件中芯片失效机理与失效分析

由于分析手段与分析设备的限制,系统级封装（SiP）组件的芯片在失效分析的过程中带有一定的盲目性。结合故障树分析方法,以PM O S芯片失效为例,讨论了SiP组件常见的管芯失效机理：电应力失效、热应力失效、机械损伤和环境应力失效以及相应的失效现象;最后从设计和工艺角度提出了降低各种失效机理发生的改进措施。     

Extending the p-cycle concept to path segment protection for span and node failure recovery

The paper introduces an extension to the method of p-cycles for network protection. The p-cycle concept is generalized to protect path segments of contiguous working flow, not only spans that lie on the cycle or directly straddle the p-cycle. The original span protecting use of the p-cycle technique is extend to include path protection or protection of any flow segment along a path. It also gives an inherent means of protecting working flows that transit a failed node. We use integer linear programming to study the new concept and determine its inherent capacity requirements relative to prior p-cycle designs and other types of efficient mesh-survivable networks. Results show that path-segment-protecting p-cycles ("flow p-cycles") have capacity efficiency near that of the shared backup path-protection (SBPP) scheme currently favored for optical networking. Because its protection paths are fully preconnected and because it protects path segments (not entire paths), it has the potential for both higher speed and higher availability than SBPP. We also develop capacity optimization models to support 100% restoration of transiting flows through failed nodes. Only a very small additional spare capacity is needed to achieve both 100% span and intermediate node-failure restorabilities, and a very high transiting traffic restorability can be accomplished for node failure restorability given spare capacity only for span-failure protection. An immediate practical application is to suggest the use of flow p-cycles to protect transparent optical express flows through a regional network.     

Data-based error compensation for georeferenced payload path tracking of automated tower cranes

In order to increase the productivity on construction sites, a current topic of research is the automation of the payload transport by tower cranes. Thereby, a key requirement is to ensure that the tower crane precisely tracks the planned paths and positions the payload at the specified target location. Most of the state-of-the-art tower crane controllers damp load sway while moving each driving system to its desired position. However, the path error also consists of bending displacements of the tower crane’s mechanical structure, observer errors, or sensor offsets once the crane hook position is considered in a fixed georeferenced construction site system. These errors have not been addressed in literature on tower cranes so far. This paper introduces an approach to reduce the path error of automated tower cranes without permanently integrating additional sensors. A regression model is derived for predicting the path error and a least absolute shrinkage and selection operator (LASSO) is used to select the most important features. The predicted error is then used to compute a compensating hook path such that the measured hook path matches the desired hook path. The effectiveness of the approach is experimentally validated utilizing a real large-scale tower crane showing a reduction of the path error of more than 50% and a position accuracy of less than 16 cm.     

静电放电作用下微波双极型晶体管的失效机理研究

通过理论建模和试验测试的方法研究了多指结构微波双极型晶体管在静电放电作用下的热稳定性和电稳定性。选择2SC3356作为受试器件,对100个测试样本进行人体模型静电放电注入实验,并从器件内部电场强度、电流密度和温度分布变化出发,用二维器件级仿真软件辅助分析了在静电放电应力下其内在损伤过程与机理。由于指间热耦合的存在,雪崩电流在各指上分布不均,局部的电流拥挤和过热效应会导致晶格损伤。试验结果表明,由于特殊的物理结构,受试器件对静电放电最敏感的端对并不是EB结,而是CB结,当静电放电电压增大到1.3KV时,CB结首先损坏。失效分析进一步表明静电放电引起的失效机理通常是介质层的击穿和局部铝硅共晶体的过热融化。静电放电注入实验的过程中存在积累效应,多次低强度的注入测试会导致潜在性失效并使器件性能大幅下降。     

Understanding the failure mechanisms of microwave bipolar transistors caused by electrostatic discharge

Electrostatic discharge(ESD) phenomena involve both electrical and thermal effects,and a direct electrostatic discharge to an electronic device is one of the most severe threats to component reliability.Therefore, the electrical and thermal stability of multifinger microwave bipolar transistors(BJTs) under ESD conditions has been investigated theoretically and experimentally.100 samples have been tested for multiple pulses until a failure occurred.Meanwhile,the distributions of electric field,current density and lattice temperature have also been analyzed by use of the two-dimensional device simulation tool Medici.There is a good agreement between the simulated results and failure analysis.In the case of a thermal couple,the avalanche current distribution in the fingers is in general spatially unstable and results in the formation of current crowding effects and crystal defects.The experimental results indicate that a collector-base junction is more sensitive to ESD than an emitter-base junction based on the special device structure.When the ESD level increased to 1.3 kV,the collector-base junction has been burnt out first.The analysis has also demonstrated that ESD failures occur generally by upsetting the breakdown voltage of the dielectric or overheating of the aluminum-silicon eutectic.In addition,fatigue phenomena are observed during ESD testing,with devices that still function after repeated low-intensity ESDs but whose performances have been severely degraded.     

基于缓冲区读取的数据源FILTER的设计与实现

DirectShow是微软公司提供的一套在Windows平台上进行流媒体处理的开发包,与DirectX开发包一起为多媒体流的捕捉和回放提供了强有力的支持,DirectShow是基于一种叫做Filter的组件进行开发和设计的,微软公司提供了许多的数据源Filter以供使用,但是却没有提供对于基于缓冲区中读取数据的Filter阐述了如何利用DirectShow技术来开发和设计这种从缓冲区读取数据的Filter,以方便对多媒体数据的处理.     

FAOG:基于过滤技术和AOG的组合电路多故障诊断算法

本文提出了一种用于组合电路中的多故障诊断的新算法FAOG（Filtered AND／OR graphs）。此算法基于过滤技术和AOG图。其中过滤技术用来除去电路中的非可能致错部分，以减少所需处理的电路规模。AOG是与电路对应的AND／OR图，是改错的关键部分。此算法对于树状组合电路是完全自动的。对于普通组合电路是半自动的。它既解决了基于模拟的改错算法只能限定出错区域而不能告知如何诊断故障信息的局限性，也大大减轻了符号诊断法的内存爆炸问题。实验表明，这是一种快速高效的故障诊断方案，适用于多故障的组合电路。     

高精度数据采集中抗混叠滤波器的设计

数据采集的精度及对数据采集的抗混叠滤波,在电路设计中是很重要的考虑因素.为了更好的实现数据采集中精度的要求,系统、全面地从ADC的驱动电路、抗混叠滤波器、后续采样/保持电路以及不同采样频率下的情况等讨论了抗混叠滤波器的设计,提出高精度数据采集中抗混叠滤波设计中应考虑的若干重要问题,指出了目前混叠滤波器设计中的不足之处,为高精度数据采集系统的设计提供了十分有益的参考.     

数字投影中填充因子对相位测量影响分析

提出了数字投影的填充因子对相位测量的误差分析。在结构光三维测量中,数字投影容易改变条纹周期和产生准确的相移,因而到了越来越广泛的应用。然而相比传统的机械模拟投影方式,数字投影采用了抽样方式,且由于其自身结构的限制,填充因子不能做到100%,必然对相位测量有影响。针对填充因子对相位测量的误差,还没有人进行充分研究。对填充因子引起误差原因进行分析,并给出其数学描述,从而建立了理论依据,还进一步提出了离焦减少误差的方法,并给出了其数学表达。最后通过模拟实验的方法,对理论进行了验证,实验结果证明了填充因子减少将增大测量误差,离焦法可以减少相位测量误差。     

基于CKF的系统误差与目标状态联合估计算法

针对量测信息中系统误差对目标状态估计精度造成 的不利影响,提出了一种基于容积卡尔曼滤波(CKF)的系统 误差与状态联合估计(JE-CKF)算法。在算法实现中,首先采用状态向量维数扩展方法建立 非线性滤波框架下的系统误差配 准模型,其次根据系统误差配准模型对量测信息中的系统误差进行估计,进而通过对CKF实 现中量测预测值 的修正,改善量测残差中系统误差对滤波精度的影响。理论分析和仿真结果验证了算法的可 行性和有效性。     

基于LabVIEW的实时数据采集和滤波处理设计

磨损是影响机械设备工作可靠性和使用寿命的主要因素之一,摩擦磨损产生的磨粒是反映设备内部磨损状况的重要载体,因此对油路中磨粒特性的监测是对机械设备进行状态监测与故障诊断的一个重要手段。本设计通过采用虚拟仪器技术,使用LabVIEW图形化编程软件和NI公司的PCI-1200数据采集卡,并结合油路磨粒检测信号的特征,设计了一...