The industry 4.0 concepts are moving towards flexible and energy efficient factories. Major flexible production lines use battery-based automated guided vehicles (AGVs) to optimize their handling ...processes. However, optimal AGV battery management can significantly shorten lead times. In this paper, we address the scheduling problem in an AGV-based job-shop manufacturing facility. The considered schedule concerns three strands: jobs affecting machines, product transport tasks’ allocations and AGV fleet battery management. The proposed model supports outcomes expected from Industry 4.0 by increasing productivity through completion time minimization and optimizing energy by managing battery replenishment. Experimental tests were conducted on extended benchmark literature instances to evaluate the efficiency of the proposed approach.
The petroleum industry has an important impact on the environment, which is why risk analysis for a petroleum storage tank is required in the process industry. However, conducting an exhaustive study ...is frequently complicated due to the incomplete data based on historical system information, feedback, or test results. The main goal of this study is to develop an innovative framework that integrates the Bow-tie method with MIMAH (Methodology for the Identification of Major Accident Hazards). This approach specifically aims to identify the most critical accident scenario and comprehensively list all realistic causes (basic events) associated with petroleum storage tanks. Acquiring historical data on basic events poses challenges due to the lack, insufficiency, and imprecision of failure data. To address this obstacle and predict the system’s evolution, a combination of established methods for handling uncertainty and multi-criteria decision-making has been proposed. This combination incorporates a modified Fuzzy Analytical Hierarchy Process with Chang’s Extent Analysis Method (FAHP-EAM), fuzzy set theory, and expert elicitation, contributing to an extensive approach for managing uncertainty and making informed decisions in the absence of comprehensive historical data. Furthermore, the Bow-tie model is converted into a dynamic Bayesian network to improve risk analysis by integrating probabilistic reasoning and capturing the dynamic interactions among multiple risk factors. This integrated approach is validated on real scenarios. The utilization of dynamic Bayesian networks further facilitates the suggestion of scenarios to assess the contribution of basic events to the critical event and evaluate the resulting environmental impacts. Finally, the prediction of threat zones for various hazardous effects, such as toxicity, thermal radiation, and overpressure linked to chemical releases following the occurrence of the critical event, is carried out. The risk analysis outcomes from this study offer valuable data for assessment, enabling managers to improve the quality of risk management and formulate effective risk mitigation strategies.
In job-shop manufacturing systems, an efficient production schedule acts to reduce unnecessary costs and better manage resources. For the same purposes, modern manufacturing cells, in compliance with ...industry 4.0 concepts, use material handling systems in order to allow more control on the transport tasks. In this paper, a job-shop scheduling problem in vehicle based manufacturing facility that is mainly related to job assignment to resources is addressed. The considered job-shop production cell has two types of resources: processing resources that accomplish fabrication tasks for specific products, and transporting resources that assure parts’ transport to the processing area. A Variable Neighborhood Search algorithm is used to schedule product manufacturing and handling tasks in the aim to minimize the maximum completion time of a job set and an improved lower bound with new calculation method is presented. Experimental tests are conducted to evaluate the efficiency of the proposed approach.
Heterarchical control architectures are essentially founded on cooperation and full local autonomy, resulting in high reactivity, no master/slave relationships and local information retention. ...Consequently, these architectures experience myopic decision-making, bringing entities towards local optimality rather than the system’s overall performance. Although this issue has been identified as an important problem within heterarchical control architectures, it has not been formally studied. The aim of this paper is to identify the dimensions of myopic behavior and propose mechanisms to control this behavior. This study focuses on myopic behavior found in manufacturing control. For this particular study, we propose a holonic framework and a holonic organization that integrates specific mechanisms to control the temporal and social myopia. Our proposal was validated using simulations designed for solving the allocation problem in flexible manufacturing systems. These simulations were conducted to show the improvement by integrating the new mechanisms. These simulation results indicate that the myopic control mechanisms achieve better performance than the reactive strategies, because not only they introduce a planning horizon, but also because they balance local and global objectives, seeking a consensus.
In literature, in different industrial fields Maintenance 4.0 standards have been studied by many researchers to improve system reliability, availability, safety and maintenance cost control. In ...Maintenance 4.0 and predictive maintenance, researchers target the development of accurate models to assess the health state of components for particular applications supporting decision making. Prior accurate knowledge to implement Maintenance 4.0 in complex systems is essential to build reliable systems. To motivate industry practitioners and our project adoption, this paper tries to offer a systemic review on Maintenance 4.0 using historical data. In this paper, an experiment on real data of rotary machine is done to provide predictive maintenance tool
Les marchés actuels sont caractérisés par une grande compétitivité. Cette compétitivité a mis les entreprises, notamment celles d'envergure internationale, dans une situation de recherche de ...compromis entre des objectifs et des contraintes de plus en plus forts et contradictoires. Cet environnement nous a conduit à développer un système de pilotage et de contrôle de production qui ne soit pas seulement capable de réagir efficacement mais qui soit également en évolution permanente pour améliorer ses performances et la qualité des solutions qu'il propose en terme d'ordonnancement. Ce système doit pouvoir exploiter au mieux les ressources de production. Pour ce faire, ces ressources subissent régulièrement des entretiens préventifs ou des corrections suite aux pannes, ce qui les rend indisponibles à ces moments. Les systèmes de pilotage de production doivent prendre en considération ces indisponibilités afin de mieux contrôler et commander le système de production. Par conséquent, production et maintenance doivent être gérées conjointement au sein du système de pilotage. Dans ce cadre, l'objectif de cette thèse est de proposer un système de pilotage qui soit réactif et capable d'améliorer en permanence ses performances. Dans cet objectif, un système basé sur l'approche multi-agent et l'apprentissage par renforcement multi-objectifs a été développé, ces techniques permettent au système d'être réactif et adaptatif à son environnement. Le système développé a été testé sur un cas réel qui est une unité de fabrication des huiles finies. Les expérimentations ont donné des résultats satisfaisants ouvrant la porte à de nouvelles perspectives.
In real-world scheduling problems, several kinds of hard-to-predict risk must be considered. Scheduling under uncertainty allows these kinds of risks to be taken into account. This paper provides an ...overview of the state of the art in scheduling under uncertainty, including a survey on modeling techniques of uncertainty and a survey of the existing positioning typologies and contributions. A new classification scheme for the different approaches to scheduling under uncertainty is proposed and discussed. Several areas for future research are suggested.
This chapter’s main interest is the myopic behaviour inherent to holonic control architectures. Myopic behaviour is the lack of coherence among local decision-making and system’s global goals. So ...far, holonic architectures use mediator entities to overcome this issue, bringing the holonic paradigms more toward hierarchy than heterarchy. Instead, this chapter explores the recursiveness characteristic of holonic manufacturing systems (HMS) as a possible way to correct myopic behaviour, by distributing decision-making over adjunct entities. The chapter explains our approach and its agent-based implementation for solving the allocation problem in a flexible job-shop. Results from simulations are compared with a mixed-integer linear program to determine its efficiency in terms of makespan and execution time. Preliminary results encourage further research in this area.
Decision process for safety based on Bayesian approach Aissani, Nassima; Mohamed Guitarni, Islam Hadj; Lounis, Zoubida
2018 3rd International Conference on Pattern Analysis and Intelligent Systems (PAIS),
2018-Oct.
Conference Proceeding
Bayesian approach is a quantitative risk analysis technique allowing a probabilistic analysis of dreaded event with their causes and effects. By creating a Bayesian Belief etwork a model knowledge ...can be developed to predict the studied system evolution. The aim of this method is to estimate a posteriori probability of the dreaded event, their causes and consequences, and gives a developed decisional support tool for risk assessment.In this paper, Bayesian approach will be experimented on safety data of a cement factory in west of Algeria (CFWA). Accident data of 6 years are saved, however some records are not completed or description is not clear generating incompleteness and uncertainty. A conceptual and generic model should be developed with a protocol for assessing the risk of injuries on persons and a computational module which constitute a decisional support system for risk assessment (DSRS). Then, experiment the model and generate many scenarios to understand and create knowledge about causes or conditions that generate those dreaded events. And finally, based on the results of this research, problem areas were determined such as struck by falling objects is a major hazard at cement industry, and convince the staff not to neglect the instructions to wear individual protection equipment (IPE).
This paper studies the problem of scheduling in a flexible job shop. A greedy heuristic is developed to solve precisely the sequencing (allocation) problem. The principle of this approach is to ...iteratively insert operations on the machines until the objective of minimizing the Cmax (makespan) is reached. The heuristic was tested on a particular Benchmark which considers the transportation times between the machines, and get inspiration from a real assembly cell: the AIP-PRIMECA cell at the University of Valenciennes, that from an OR perspective, can be viewed as Flexible Job Shop, leading to the formulation of a Flexible Job-Shop Scheduling Problem (FJSSP). The results obtained by the greedy heuristic on this benchmark are very promising.
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