RELIABILITY THEORY: HISTORY & CURRENT STATE IN BIBLIOGRAPHIES

Actually, this is not a review of past and recent works on reliability theory and adjoining areas.  It is rather a selected bibliography with brief comments. Of course, any such selected bibliography  or review reflects knowledge, experience and even scientific taste of the author. Nevertheless, I hope that, in general, the depicted picture of recent reliability theory state is more or less objective. Reliability Theory is alive but is it still developed? That’s the question. “History teaches the continuity of the development of science.  We know that every age has its own problems, which the following age either solves or casts aside as profitless and replaces by new ones.”  This is a citation from David Hilbert’s Lecture “Mathematical Problems” delivered in 1900.  Hilbert told about pure mathematics, however the same words are correct in respect to applied mathematics and, in particular, to reliability theory.

COMPREHENSIVE cable failures ANALYSIS FOR PROBABILISTIC fire SAFETY ASSESSMENTS

Fire PSA for all plant operational states is part of a state-of-the-art that a Level 1 PSA. Within a fire PSA not only the malfunction of systems and components has to be assessed but also all supply systems and cables have to be traced for a given component. In the past it was assumed that in the case of a fire in a compartment all components and corresponding cables in that compartment are destroyed. However, this is in many cases a very conservative approach which may lead to overestimated fire induced core damage frequencies. Therefore, a method is required to assess in a more realistic manner the effects of cables failures caused by fire. Such a procedure is based on a sound data base containing all relevant equipment, a list of cables and their properties as well as cable routing. Two methods which are currently developed and already partially applied are described in more detail. One of these methods is a cable failure mode and effect analysis which is easier to apply in practice.

How TO Assess external explosion PRESSURE WAVES

External hazards can be safety significant contributors to the risk in case of operation of industrial plants. This has been strongly underlined by the nuclear accidents at Fukushima-Daiichi in March 2011.The paper concentrates on the procedure to assess external hazard explosion pressure waves within probabilistic safety assessment. This assessment starts with a screening procedure in order to determine scope and content of the analysis. The second step is to choose an appropriate approach in case that a full scope analysis has to be performed. Several methods can be applied to evaluate the probability of occurrence of an external explosion event at a plant. The presented results indicate that the probability of occurrence of external explosion pressure waves can be successfully assessed by means of the Monte Carlo simulation, in particular in difficult site-specific conditions.

THE PROCESSING OF THE MEDICAL DATA WITH THE USE OF LOGISTIC REGRESSSION

This paper shows the evaluation of the data coming from the surgery operations and from the clinique of occupational and preventive medicine. Deals with the usage of logistic regression for predicting the classification of patients into one of the two groups. Our data come from patients who underwent Phadiatop test examinations and patients who underwent colectomy in the University Hospital of Ostrava. For Phadiatop test, as the predictor variables were chosen personal and family anamneses. Both of these anamneses were divided into four categories according to severity ranked by doctors. The model for Phadiatop test was tested with the use of a medical database of 1027 clients. The developed models predict the right results with 75% probability for Phadiatop.  For colectomy operation we were the physiological and operative scores as predictor variables. Scores for Colectomy operation were based on the POSSUM system (Copeland et al. 1991). The psychological score comprises 12 factors and the operative score comprises 6. Colectomy operation was tested upon a medical database of 364 clients. The developed models are successful with 70% probability for morbidity in surgery.

The reverse logistics model with reusing of components of series system product

The main goal of this paper is to create the reverse logistics model that uses reliability theory to describe reusability of product parts with assumption that recovered components are used in production process but they aren’t as good as new ones. The model allows to estimate the potential profits of the reusing policy in a production and gives the base to optimize some of the process parameters: the threshold work time of returns or the warranty period for products containing reused elements.

The reverse logistics model with  reusing of  product parts

Main goal of this paper is to create the reverse logistics model that uses reliability theory to describe reusability of product parts with assumption that recovered components are used in process of new products manufacturing. Authors assume that they aren’t as good as new ones which is an important difference compared to the most models that were created before. The model allows to estimate the potential profits of the reusing policy in a production and gives the base to optimize some of the process parameters: the threshold work time of returns or the warranty period for products containing reused elements.

The reverse logistics forecasting model with whole product recovery

Classical logistics systems supports only processes carried out in material flow from manufacturer to final user. Recently it has been a striking growth of interest in optimizing logistics processes that supports recapturing value from used goods. The process of planning, implementing, and controlling the efficient, cost effective flow of raw materials, in-process inventory, finished goods and related information from the point of consumption to the point of origin for the purpose of recapturing value or proper disposal is called reverse logistics. The main goal of this paper is to create the forecasting model to predict returns quantity for reverse logistics system that supports processes of recapturing value from used products that has been decommissioned (because of failure) before a certain time called an allowable working time before failure.

A FRAMEWORK FOR SELECTION OF TEST METHOD AND TEST INTERVAL FOR SAFETY CRITICAL VALVES IN SITUATIONS WITH LIMITED DATA

In this paper we present a practical framework that can support the decision on test methods and test intervals for safety critical valves in situations where limited relevant historical data is available. The framework is based upon a systematic review of the valve functions and associated failure modes, as well as properties of the environment that the valve is located in, and evaluation of this knowledge in qualitative expert workshops. The main application area for the framework is valves located upstream or downstream of large gas transport pipeline segments. The framework is however general and can be applied to smaller hydrocarbon segments as well.

RELIABILITY, RISK AND AVAILABILITY ANALYSIS OF A CONTAINER GANTRY CRANE

The joint model of the system operation process and the system multi-state reliability is applied to the reliability, risk and availability evaluation of the container gantry crane. The container gantry crane is described and the mean values of the container gantry crane operation process unconditional sojourn times in particular operation states are found  and  applied to determining this process transient probabilities in these states. The container gantry crane different reliability structures in various its operation states are fixed and their conditional reliability functions on the basis of data coming from experts are approximately determined. Finally, after applying earlier estimated transient probabilities and system conditional reliability functions in particular operation states the unconditional reliability function, the mean values and standard deviations of the container gantry crane lifetimes in particular reliability states, risk function and the moment when the risk exceeds a critical value are found. Next the renewal and availability characteristics for the considered gantry crane are determined.

SAFETY ANALYSIS AND ASSESSMENT IN THE WATER SUPPLY SECTOR

The paper presents a framework for the analysis of performance risk in water supply system (WSS) that can be applied to the entire system or to individual subsystems. It provided a background for the rules of management formulation. The aim of such management is to prepare resources and society for the case of an undesirable event occurrence which causes threat to health, property, environment and infrastructure. The risk elements, which always accompany crisis, have been presented.

COMPLETE CALCULATION OF DISCONNECTION PROBABILITY IN PLANAR GRAPHS

In this paper complete asymptotic formulas for an disconnection probability in random planar graphs with high reliable arcs are obtained. A definition of coefficients in these formulas have geometric complexity by a number of arcs. But a consideration of planar graphs and dual graphs allow to solve this problem with no more than cubic complexity by a number of graph faces. 

THE AMENDMENT TO AMDAHL ` S THE LAW

Law Amdahl, sometimes also law Аmdahl-Uer, shows restriction of growth of productivity of the computing system with increase of quantity of calculators. It also is applicable to collective of people solving a problem, admitting parallels decisions between its members. John Amdahl has formulated the law in 1967, having found out idle time in essence, but insuperable restriction under the maintenance on growth of productivity at parallels calculations: «In a case when the problem is divided on some parts, total time of its performance for parallel system can not be less time of performance of the longest fragment ». According to this law, acceleration of performance of the program for the account parallels its instructions on set of calculators is limited to time necessary for performance of its consecutive instructions