水泥企业电气常见“软故障”的快速判断方法

现代化水泥企业电气设备种类繁多,掌握一些快速判断和处理问题尤其是各种"软故障"的方法,就能保证生产连续稳定运行。电动机机械故障的判断方法。电动机常见电气故障的判断方法。电气回路接触不良造成的故障。电气回路干扰造成的故障。

小麦收割机的“软故障”的排除与分析

简要介绍了小麦收割机的作业工艺流程,清选原理,"软故障"

松立S-6003C型VCD三碟机软故障检修感悟

“软故障”泛指某电路元件并非明显损坏而不能进行正常工作，如晶体管、集成电路性能变差，电容失容、漏电，电阻变值或稳定性变差等。软故障的特点是故障点隐蔽，故障特征各异，通常用“怪”、“杂”、“假”来形容。笔者在检修松立S-6003C型VCD机时深有体会，感悟颇深，现将其检修经过写出，供维修人员参考。

FANUC AC伺服特殊故障的维修

在数控机床维修过程中,有时会遇到一些比较特殊的故障,例如:有的机床在刚开机时系统和机床工作正常,但是,当工作一段时间后,将出现某一故障。这种故障有的通过关机清除后,机床又可以重新工作;有的必须经过较长的关机时间,让机床“休息”一段时间,机床才能重新工作。此类故障常常被人们称为“软故障”。 “软故障”的维修通常是数控机床维修中最难解决的问题之一。

电磁屏蔽法在天气雷达维修中的应用

天气雷达可以有效探测台风、雷雨、冰雹等灾害性天气的影响范围,精确跟踪目标物的移动路径,被广泛运用于气象防灾减灾的监测预警以及民航系统的飞行安全保障中。双偏振多普勒天气雷达在具备常规多普勒天气雷达探测降水反射率因子、径向移动速度和谱宽的基础上,还能测算差分反射率因子、差分相位、差分常数、相关系数并识别降水的相态,也成为气象部门探测强对流等危险天气的首选装备。以中医问诊方式介绍了天气雷达故障后的常规维修方法,同时介绍了采用电磁屏蔽法解决天气雷达发生"软故障"的一些案例,为天气雷达保障人员在维修过程中提供了一种维修方法,以供大家参考。

Predicting the fault-proneness of class hierarchy in object-oriented software using a layered kernel

A novel kernel learning method for object-oriented （00） software fault prediction is proposed in this paper. With this method, each set of classes that has inheritance relation named class hierarchy, is treated as an elemental software model. A layered kernel is introduced to handle the tree data structure corresponding to the class hierarchy models. This method was vali- dated using both an artificial dataset and a case of industrial software from the optical communication field. Preliminary experi- ments showed that our approach is very effective in learning structured data and outperforms the traditional support vector learning methods in accurately and correctly predicting the fault-prone class hierarchy model in real-life OO software.

Numerical simulation on fault water-inrush based on fluid-solid coupling theory

About 75% water-inrush accidents in China are caused by geological structure such as faults, therefore, it is necessary to investigate the water-inrush mechanism of faults to provide references for the mining activity above confined water. In this paper, based on the fluid-solid coupling theory, we built the stress-seepage coupling model for rock, then we combined with an example of water-inrush caused by fault, studied the water-inrush mechanism by using the numerical software COMSOL Mutiphysics, analyzed the change rule of shear stress, vertical stress, plastic area and water pressure for stope with a fault, and estimated the water-inrush risk at the different distances between working faces and the fault. The numerical simula- tion results indicate that： （1） the water-inrush risk will grow as the decrease of the distance between working face and the fault; （2） the failure mode of the rock in floor with fault is shear failure; （3） the rock between water-containing fault and working face failure is the reason for water-inrush.

Experimental Study on Cyclic Mechanics Characteristic of Saturated Soft Clay Strata

Failure criterion of saturated soft clay is studied under cyclic loads through different experiments. A large number of cyclic torsional shear and cyclic triaxial tests on saturated soft clay under unconsolidated undrained condition are conducted. From the test result analysis, it is seen that the failure of saturated soft clay under static and cyclic loads satisfies Mises criterion. The result from different test stress states is not related to the test stress states or confining pressures. It can be applied in general stress states. Then according to the Mises criterion, the equivalent relationship on failure moment between the test stress state and the general stress state can be established. So the cyclic mechanics characteristics of saturated soft clay at failure moment are clarified in this paper. Furthermore, a theory basis is provided for using pseudo-static elasto-plastic cyclic strength model to evaluate cyclic bearing capacity.

AN ALGORITHM FOR FAULT DIAGNOSIS BASED ON COMBINATORIAL DESIGN APPROACH FOR TESTING

Much research has been done mainly in testcase generation and its effect for com-binatorial design approach for testing. This letter presents an algorithm for fault diagnosis basedon the approach. It can conclude that the factors, which cause errors, must be in a very smallrange through analyzing the test cases after testing, and retesting with some complementary testcases. The algorithm can provide a very efficient and valuable guidance for the debugging andtesting of software.

Power swing and voltage collapse identification schemes for correct distance relay operation in power system

The new techniques were presented for preventing undesirable distance relay maloperation during voltage collapse and power swings in transmission grids. Initially, the work focused on the development of a fast detection of voltage collapse and a three-phase fault at transmission lines by using under impedance fault detector (UIFD) and support vector machine (SVM). Likewise, an intelligent approach was developed to discriminate a fault, stable swing and unstable swing, for correct distance relay operation by using the S-transform and the probabilistic neural network (PNN). To illustrate the effectiveness of the proposed techniques, simulations were carried out on the IEEE 39-bus test system using the PSS/E and MATLAB software.

Stochastic differential equation software reliability growth model with change-point

This paper presents software reliability growth models(SRGMs) with change-point based on the stochastic differential equation(SDE).Although SRGMs based on SDE have been developed in a large scale software system,considering the variation of failure distribution in the existing models during testing time is limited.These SDE SRGMs assume that failures have the same distribution.However,in practice,the fault detection rate can be affected by some factors and may be changed at certain point as time proceeds.With respect to this issue,in this paper,SDE SRGMs with changepoint are proposed to precisely reflect the variations of the failure distribution.A real data set is used to evaluate the new models.The experimental results show that the proposed models have a fairly accurate prediction capability.

Fault injection system for automatic testing system

Considering the deficiency of the means for confirming the attribution of fault redundancy in the re-search of Automatic Testing System(ATS) , a fault-injection system has been proposed to study fault redundancyof automatic testing system through compurison. By means of a fault-imbeded environmental simulation, thefaults injected at the input level of the software are under test. These faults may induce inherent failure mode,thus bringing about unexpected output, and the anticipated goal of the test is attained. The fault injection con-sists of voltage signal generator, current signal generator and rear drive circuit which are specially developed,and the ATS can work regularly by means of software simulation. The experimental results indicate that the faultinjection system can find the deficiency of the automatic testing software, and identify the preference of fault re-dundancy. On the other hand, some soft deficiency never exposed before can be identified by analyzing the tes-ting results.

Deformation failure and countermeasures of deep tertiary extremely soft rock roadway in Liuhai coal mine

In view of failure phenomena with nonlinear large deformation including extensive damage,whole section destruction in short time,high rate of repair,most destruction forms occurred in the tertiary roadway of soft rocks engineering in Liuhai mine,according to the methods of geological survey,theoretical analysis,numerical calculation and in-situ test,the composite failure mechanism of molecular expansion,tectonic stress,gravity stress and engineering deviatoric stress,faults and random joint in this area is analyzed deeply,then an coupling support of double-layer-truss is proposed.The research results show that the first wave of deformation energy was released by bolt-mesh-cable fixed into the roof,floor and two sides of the roadway.While the second wave of deformation energy was released through the interface function between double-layer-truss and the surrounding rock.The double-layer-truss that characterized by high strength,good integrity can absorb high deformation energy of surrounding rocks,which led to the uniform distribution of the stress.Engineering practice shows this technology has been successfully applied to control the deformation failure of the tertiary extremely soft rock roadway.

Empirical analysis of network measures for predicting high severity software faults

Network measures are useful for predicting fault-prone modules. However, existing work has not distinguished faults according to their severity. In practice, high severity faults cause serious problems and require further attention. In this study, we explored the utility of network measures in high severity faultproneness prediction. We constructed software source code networks for four open-source projects by extracting the dependencies between modules. We then used univariate logistic regression to investigate the associations between each network measure and fault-proneness at a high severity level. We built multivariate prediction models to examine their explanatory ability for fault-proneness, as well as evaluated their predictive effectiveness compared to code metrics under forward-release and cross-project predictions. The results revealed the following:(1) most network measures are significantly related to high severity fault-proneness;(2) network measures generally have comparable explanatory abilities and predictive powers to those of code metrics; and(3) network measures are very unstable for cross-project predictions. These results indicate that network measures are of practical value in high severity fault-proneness prediction.

Software reliability analysis considering correlated component failures with coupling measurement framework

With progression of the digital age, the complexity of software continues to grow. AS a result, methods to quantitatively assess characteristics of software have attracted significant atten- tion. These efforts have led to a large number of new measures such as coupling metrics, many of which seek to consider the impact of correlations between components and failures on ap- plication reliability. However, most of these approaches set the coupling parameters arbitrarily by making assumptions instead of utilizing experimental data and therefore may not accurately capture actual coupling between components of software applica- tion. Since the coupling matrix is often set arbitrarily, the existing approaches to assess software reliability considering component correlation fail to reflect the real degree of interaction and rela- tionships among software components. This paper presents an efficient approach to assess the software reliability considering Correlated component failures, incorporating software architec- ture while considering actual internal coupling of software with an efficient approach based on multivariate Bernoulli （MVB） distribu- tion. The unified framework for software Coupling measurement is＇ informed by a comprehensive survey of frameworks for object- oriented and procedure-oriented software. This framework enables the extraction of more accurate coupling among cornponents. The effectiveness of this method is illustrated through an exPerimental study bylapplying it to a real-time software application.