Grey Entropy Relation Algorithm of Choosing the Optimum Diagnostic Nodes in Analogue Circuits

Choosing the optimum diagnostic nodes is helpful to increase the accuracy and the efficiency of circuits fault diagnosis. Grey entropy relation algorithm is proposed to choose the optimum diagnostic nodes of analogue circuits in this paper. Analogue circuits are regarded as grey system. Grey relation analysis and grey entropy analysis are combined to grey entropy relation algorithm. Grey entropy relation algorithm is used to quantify the relationship between the diagnostic nodes and fault components. The relevance between the diagnostic nodes and fault components can be evaluated by grey entropy relation degrees. According to the rank order of grey entropy relation degrees, the optimum diagnostic nodes of analogue circuits can be selected objectively and accurately. An example of fault diagnosis is presented to verify the validity of the optimum diagnostic nodes.     

A systems approach to organizational error

Abstract

The past two decades have seen a significant number of large-scale disasters in a wide range of hazardous, well-defended technologies. Despite their differences, the root causes of these accidents have been traced to latent failures and organizational errors arising in the upper echelons of the system in question. A model of the aetiology of these organizational accidents is outlined. The model describes two interrelated causal sequences: (a) an active failure pathway that originates in top-level decisions and proceeds via error-producing and violation-promoting conditions in the various workplaces to unsafe acts committed by those at the immediate human-system interface and (b) a latent failure pathway that runs directly from the organizational processes to deficiencies in the system's defences. The paper goes on to identify two sets of dependencies associated with latent failures and violations. Organizational errors increase the likelihood of operator error through the active failure pathway and, at the same time, enhance the possibility of adverse outcomes through defensive weaknesses. Violations have a narrower range of consequences. Non-compliance with safe operating procedures increases the likelihood of error by taking perpetrators into regions of operation in which neither the physical regime nor the hazards are well understood. Violations, by definition, also take perpetrators ‘closer to the edge,’ and thus increase the chance that subsequent errors will have damaging outcomes. The paper concludes by indicating two ways in which the model has been applied in industrial settings: (a) through the development of proactive measures for diagnosing and remedying organizational processes known to be implicated in accident causation, and (b) an accident investigation technique that guides investigators and analysts to the organizational root causes of past accidents.     

Optimisation of design parameters for collimators and pin-holes of bolometer cameras

The total radiation emission profile of fusion experiments is usually determined using the bolometer diagnostic. In order to evaluate the spatially resolved profile, many line integrated measurements are inverted using tomographic reconstruction techniques. Their success depends on a well known and optimised definition of the viewing cones of every line-of-sight. To this aim a set of equations has been derived and put in hierarchical order to define the design parameters for bolometer cameras in fusion experiments. In particular, previous considerations, which focussed on the beam width overlap and light yield optimisation, are extended to explicitly take geometrical boundary conditions imposed by the experimental device into account, with an emphasis on small gap sizes through which viewing cones have to pass through. The equations are derived for both camera types, collimator and pin-hole versions. The results obtained can be used to design bolometer cameras for any fusion device, but in particular also for ITER. An example of such an application is given and implications for the realisation of the optimal design are discussed.     

Modelling the dynamics of design error induced rework in construction

Rework that is experienced in construction projects is often caused by errors made during the design process. Factors that contribute to design errors are identified and used to design and develop a systems dynamics model, which is used to simulate a number of practical scenarios that can be used to reduce design errors and rework. The model presented in this paper can enable design and project managers to understand better the process of design documentation and how design errors occur in construction projects.     

Proton exchange membrane fuel cell system diagnosis based on the multivariate statistical method

Although electric-powered vehicles have developed rapidly in recent years, with significant progress in the lithium power battery industry, the Fuel Cell Electric Vehicle (FCEV) is still a competitive choice for a clean transportation solution, because of its extended driving range, zero emissions, and fast fuel recharging capability. In particular the fuel cell hybrid bus used for city traffic is the FCEV type most likely to be commercialized. Demonstration programs for a fuel cell bus fleet have been operated for a few years in China. It is necessary to develop comprehensive diagnostic tools to increase the reliability of these systems, because fuel cell city buses serve large numbers of passengers using public transportation. This paper presents a diagnostic analysis and implementation study based on the Principal Component Analysis (PCA) method for the fuel cell system. This diagnostic system was successfully implemented for detecting a fuel cell stack sensor network failure in the fuel cell bus fleet at the Shanghai Expo in 2010.     

深部岩体稳定性评价的声发射—压力耦合模式

以海沟金矿的大面积采空区为研究对象,将压力观测,声发射检测,位移观测等多种手段联合用于采空区围岩的稳定性监测,通过分析各种信息之间的耦合关系,得到了由压力和声发射联合表示的岩体稳定性评价的三种“判别模式”,即升压稳定模式,降压稳定模式和降压不稳定模式,实践表明,所得到的判别式利用了压力和声发射这两种普通信息之间的“耦合内涵,因而有着更好的可操作性,更宜于现场监测人员的理解和掌握。     

The Analysis of Closed-Loop Dynamic-Stochastic Systems

Certain types of non-linear transformations of stochastic signal processes have proven useful in engineering applications. A form of processing called hard clipping (or hard limiting) has frequently been used in electronic systems which work in “real time” in order to reduce the number of information bits which the system has to process. With hard clipping only one binary digit is used per sample value of an input signal X(t). However, information is lost about X(t) and the spectrum which is calculated from the clipped signal is a distorted form of the original signal spectrum. By a sine transformation of the sample covariance of the clipped process, a consistent estimator is derived for the spectral density of X(t). The asymptotic variance-covariance function is calculated for this estimator.     

A meta-analytic investigation of the structure of posttraumatic stress disorder symptoms.

Converging lines of evidence have called into question the validity of conceptualizations of posttraumatic stress disorder (PTSD) based on the Diagnostic and Statistical Manual of Mental Disorders (DSM; American Psychiatric Association, 2000) and suggested alternative structural models of PTSD symptomatology. We conducted a meta-analysis of 40 PTSD studies (N = 14,827 participants across studies) that used a DSM-based measure to assess PTSD severity. We aggregated correlation matrices across studies and then applied confirmatory factor analysis to the aggregated matrices to test the fit of competing models of PTSD symptomatology that have gained support in the literature. Results indicated that both prominent 4-factor models of PTSD symptomatology yielded good model fit across subsamples of studies; however, the model comprising Intrusions, Avoidance, Hyperarousal, and Dysphoria factors appeared to fit better across studies. Results also indicated that the best fitting models were not moderated by measure or sample type. Results are discussed in the context of structural models of PTSD and implications for the diagnostic nosology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overview of Human Factors and Ergonomics in the OR,with an Emphasis on Minimally Invasive Surgeries

Operating rooms (OR) are where medical teams work to improve the health of a patient. However, because of the complexity of the procedures, errors and unsafe situations are likely to occur. These complications can lead to harm to the patient or medical professionals. Human factors and ergonomic professionals have been working to improve these unsafe conditions in the OR for over a century. However, with advances in technology, increased surgical complexity, as well as an increase in medical team members in the OR, there are still numerous improvements yet to be accomplished. Minimally invasive surgeries require an even more advanced approach to prevent errors due to technology, fatigue, and miscommunication. Human factors and ergonomic techniques provide the ability to greatly improve conditions for patients and surgeons alike. It is imperative that human factors and ergonomics continue to grow and facilitate technological advancements in healthcare. © 2012 Wiley Periodicals, Inc.     

Estimators of sensitivity and specificity in the presence of verification bias: A Bayesian approach

Verification bias can occur if some of the patients with test results are not selected to receive the gold standard procedure. Unverified cases frequently are not suggestive to be positives. Consequently, the set of verified cases overestimates the number of true positives and underestimates the number of true negatives. The sensitivity and specificity estimates based only on the patients with verified disease are often biased. In this article we derive estimators for sensitivity and specificity not subject to verification bias using a Bayesian approach. Marginal posterior densities of all parameters are estimated using the Gibbs sampler algorithm. An application to the study of accuracy of Hybrid Capture II in the diagnosis of cervical intraepithelial neoplasia grades 2 and 3 illustrates the proposed methodology.