Fig 3 - uploaded by A. Zeblah
Content may be subject to copyright.
Source publication
This paper combine the universal generating function UGF with harmony search (HSO) meta-heuristic optimization method to solve a preventive maintenance (PM) problem for series-parallel system. In this work, we consider the situation where system and its components have several ranges of performance levels. Such systems are called multi-state system...
Similar publications
This paper combines the universal generating function UGF with harmony search (HSO) meta-heuristic
10 optimization method to solve a preventive maintenance (PM) problem for series-parallel system. In this work, we con-
11 sider the situation where system and its components have several ranges of performance levels. Such systems are called
12 multi-...
Citations
... In an additional research, Tian and Liao (2011) performed a similar work on multi-component systems. The study performed by Harrou et al. (2009) is an excellent work in the field. They formulated the problem of imperfect maintenance optimization for series-parallel transmission system structure. ...
... In this paper, UGF method is used to estimate reliability of the system. This method, convenient for numerical implementation, proved to be very effective for high dimension combinatorial problems (Harrou and Zeblah 2009). In this method, the z-transform J Intell Manuf Fig. 1 A binary-state series-parallel system of each random variable X i that implies component i in the system, represents its probability mass function (p.m.f.) (x i0 , ..., x ik ), ( p i0 , ..., p ik )in the polynomial form u i (z) = k i j=0 p i j z x i j in which x i j represents working level of component i and p i j is the probability that the component works at this level. ...
The change of market and the explosion of product variety have led to increased automation and the need for complex equipment. Therefore, the reliability and the maintainability of the equipment play an important role in controlling both the quantity and quality of the products. In order to ensure specified availability and reliability of production process, preventive maintenance (PM) should be taken during production process. However, taking unscheduled PM can impose high costs to the firm, and adversely decrease the reliability of production line. In this paper, a multi-objective PM scheduling problem in a multiple production line is considered. Reliability of production lines, costs of maintaining, failure and downtime of system are measured as multiple objectives, and different thresholds for available manpower, spare part inventory and periods under maintenance is applied. Production system in this paper consists of serial and parallel machines. Finally, a test problem has been solved to show the effectiveness of the proposed model.
... harmony search methods. Harrou and Zeblah combined the universal generating function with the harmony search metaheuristic optimization method to solve a preventive maintenance problem for a series parallel system [30]. ...
In recent years, the problem of optimum reconfiguration in distribution systems (DSs) has been a task that must be solved in an optimal manner. This paper presents a new approach for the optimal reconfiguration of DSs based on a hierarchical 2-stage optimization problem to improve the power system voltage stability margin and reduce losses incorporating the constraints. The mentioned problem has been modeled as a nonlinear and multiobjective optimization problem. It uses the ability of the developed harmony search algorithm (HSA) as the first stage of the proposed optimization problem to reach the best network configuration. This reconfiguration algorithm starts with a radial topology by a theoretical approach that is based on the graph concept and matroid theory. These concepts are used in order to propose new intelligent HSAs to form a new harmony vector that is well dedicated to the DS reconfiguration problem. Thus, all of the resulting individuals after forming a new harmony vector are claimed to be feasible configurations. Moreover, the presented approach is valid and avoids tedious mesh checks for the topology constraint validation. In the second stage of the proposed approach, the voltage stability index is calculated to evaluate the static voltage stability security margin for each reconfiguration pattern. Hence, a toolbox has been developed to recognize the loadability limit of DSs based on the Lagrangian optimization method. Finally, the proposed method establishes a tradeoff between the security index and power losses to reach a coordinated reconfiguration pattern. To demonstrate the validity of the proposed method, the simulations are carried out on 33- and 69-bus IEEE DSs. The proposed method is finally compared to some previous techniques used by other authors. The results show a good enhancement in the security margin and smaller power losses with considerably less computation effort. To validate the proposed method, the results that were obtained from the HSA are compared with the particle swarm optimization algorithm to ascertain its effectiveness.
Dans le cadre du développement de réseaux de capteurs autonomes pour la surveillance globale de systèmes complexes, l'objectif est de développer un modèle de fiabilité de la partie électronique du capteur qui est de structure complexe. En utilisant les théories de la fiabilité des composants électroniques et les modèles markoviens pour l'étude de fiabilité des systèmes électroniques, on construit le modèle de dégradation et calcule la fiabilité du système. A partir de ces données, on essaie de prévoir l'état du système par plusieurs méthodes différentes selon le problème posé. L'objectif principal est de fournir une prédiction en continue et en temps réel de l'état du système. Les travaux effectués portent sur les aspects suivants: Etude bibliographique sur les problèmes d'évaluation la fiabilité des systèmes électroniques et sur les méthodes d'évaluation avancées susceptibles d'être adaptées puis exploitées dans le contexte envisagé. Modélisation et développement de méthodes de résolution pour l'évaluation de fiabilité du système électronique proposé. Réalisation d'une compagne de validation du modèle à l'aide de données connues sur ce type de système. Les résultats de l'étude nous montrent les causes de défaillance et les modes de dégradation des composants électroniques et du système électroniques sur lesquelles on peut prévoir plus exactement les états de système ou la durée de vie du système.
