Monitoring of Complex Processes with Bayesian Networks

This chapter is about the multivariate process monitoring (detection and diagnosis) with Bayesian networks. It allows to unify in a same tool (a Bayesian network) some monitoring dedicated methods like multivariate control charts or discriminant analysis. After the context introduction, we develop in section 2, principles of process monitoring, namely fault detection and fault diagnosis. We presents classical statistical techniques to achieve these tasks. In section 3, after a presentation of Bayesian networks (with discrete and Gaussian nodes), we propose the modeling of the two tasks (detection and diagnosis) in the Bayesian network framework, unifying the two steps of the process monitoring in a sole tool, the Bayesian network. An application is given in section 4 in order to demonstrate the effectiveness of the proposed approach. This application is a benchmark problem in process monitoring: the Tennessee Eastman Process. Efficiency of the network is evaluated for detection and for diagnosis. Finally, we give conclusions on the proposed approach and outlooks concerning the use of Bayesian network for the process monitoring

Modeling Analysis of Power Transformer Fault Diagnosis Based on Improved Relevance Vector Machine

A new method of transformer fault diagnosis based on relevance vector machine (RVM) is proposed. Bayesian estimation is applied to support vector machine (SVM) in the novel algorithm, which made fault diagnosis system work more effectively. In the paper, the analysis model is presented that the solutions of RVM have the feature of sparsity and RVM can obtain global solutions under finite samples. The process of transformer fault diagnosis for four working statuses is given in experiments and simulations. The results validated that this method has obvious advantages of diagnosis time and accuracy compared with backpropagation (BP) neural networks and general SVM methods

Using Bayesian Networks for Candidate Generation in Consistency-based Diagnosis

Consistency-based diagnosis relies heavily on the assumption that discrepancies between model predictions and sensor observations can be detected accurately. When sources of uncertainty like sensor noise and model abstraction exist robust schemes have to be designed to make a binary decision on whether predictions are consistent with observations. This risks the occurrence of false alarms and missed alarms when an erroneous decision is made. Moreover when multiple sensors (with differing sensing properties) are available the degree of match between predictions and observations can be used to guide the search for fault candidates. In this paper we propose a novel approach to handle this problem using Bayesian networks. In the consistency- based diagnosis formulation, automatically generated Bayesian networks are used to encode a probabilistic measure of fit between predictions and observations. A Bayesian network inference algorithm is used to compute most probable fault candidates

On Fault Diagnosis using Bayesian Networks ; A Case Study of Combinational Adders.

In this paper, we use Bayesian networks to reduce the set of vectors for the test and the diagnosis of combinational circuits. We are able to integrate any fault model (such as bit-flip and stuck-at models) and consider either single or multiple faults. We apply our method to adders and obtain a minimum set of vectors for a complete diagnosis in the case of the bit-flip model. A very good diagnosis coverage for the stuck-at fault model is found with a minimum set of test vectors and a complete diagnosis by adding few vectors

A Bayesian Argumentation Framework for Distributed Fault Diagnosis in Telecommunication Networks

Traditionally, fault diagnosis in telecommunication network management is carried out by humans who use software support systems. The phenomenal growth in telecommunication networks has nonetheless triggered the interest in more autonomous approaches, capable of coping with emergent challenges such as the need to diagnose faults' root causes under uncertainty in geographically-distributed environments, with restrictions on data privacy. In this paper, we present a framework for distributed fault diagnosis under uncertainty based on an argumentative framework for multi-agent systems. In our approach, agents collaborate to reach conclusions by arguing in unpredictable scenarios. The observations collected from the network are used to infer possible fault root causes using Bayesian networks as causal models for the diagnosis process. Hypotheses about those fault root causes are discussed by agents in an argumentative dialogue to achieve a reliable conclusion. During that dialogue, agents handle the uncertainty of the diagnosis process, taking care of keeping data privacy among them. The proposed approach is compared against existing alternatives using benchmark multi-domain datasets. Moreover, we include data collected from a previous fault diagnosis system running in a telecommunication network for one and a half years. Results show that the proposed approach is suitable for the motivational scenario

Transformation of Fault Trees into Bayesian Networks Methodology for Fault Diagnosis

International audienceIn this article, we have shown an application of a decision support tool which is the FTBN, The combination of Bayesian Network (BN) with Fault Tree (FT) is an interesting approach to diagnose mechanical systems. Bayesian networks are tools provide robust probabilistic methods of reasoning under uncertainty, widely used in the field of reliability and fault diagnosis. While fault tree is a method of deductive analysis based on the realization of a tree that is used to identify combinations of failures, since both tools have a probabilistic aspect, the main purpose of this works is to give a methodological approach based on the transformation method of fault tree into bayesian network to model a mechanical systems, And more specifically the fault diagnosis.Fault tree construction allows building a Bayesians network. This step allows deriving the graphical structure of the bayesian network that represents the causal relationship between the different events, and exploits the mass of existing data (experience feedback database) of the system under study.In this paper a methodology approach is used to conduct quantification of conditionals probabilities of this Network, and performed a diagnosis on the out of balance trough modeled scenarios.The proposed methodology in our paper is centred on the presence or absence of the out of balance of the motor pump. Knowing that the source of this unbalance is caused by tows essentially events in the fault tree: Bending rotor and Break of vanes