Fouad Riane

A hybrid three-stage flowshop problem: Efficient heuristics to minimize makespan

We treat a problem of scheduling n jobs on a three stages hybrid flowshop of particular structure (one machine in the first and third stages and two dedicated machines in stage two). The objective is to minimize the makespan. This problem is NP-complete. We propose two heuristic procedures to cope with realistic problems. Extensive experimentation with various problem sizes are conducted and the computational results show excellent performance of the proposed heuristics.

Exact and heuristic methods for the selective maintenance problem

We present in this paper, new resolution methods for the selective maintenance problem. This problem consists in finding the best choice of maintenance actions to be performed on a multicomponent system, so as to maximize the system reliability, within a time window of a limited duration. When the number of components of the system is important, this combinatorial problem is not easy to solve, in particular because of the nonlinear objective function modeling the system reliability. This problem did not receive much attention yet. Consequently, rare are the effective resolution methods that are offered to the user. We thus developed heuristics and an exact method based on a branch and bound procedure, which we apply to various system configurations. We compare the obtained results, and we evaluate the best method to be used in various situations.

Operating Theatre Optimization : A Resource-Constrained Based Solving Approach

The operating theatre is considered as the bottleneck of the hospital and as one of the most resources consuming unit. Therefore its management is of primary interest: an efficient planning allows to use as better as possible the availability of the operating theatre and reduce human and financial working costs. This paper deals with operating theatre planning optimization. We present a mathematical model combining surgeries planning and scheduling over short time horizon, and by taking into account renewable and nonrenewable resources availabilities. This model gets its inspiration from project management and especially resource-constrained project scheduling problem (RCPSP). We also introduce a genetic algorithm approach to heuristically solve the problem. We base our approach on the multi-mode variation of the RCPSP to define the related crossover, mutation and selection operators allowing the global search to work effectively

Sequencing a hybrid two-stage flowshop with dedicated machines

We treat the n -job, two-stage hybrid flowshop problem with one machine in the first stage and two different machines in parallel in the second stage. The objective is to minimize the makespan. We demonstrate that the problem is NP-complete. We formulate a dynamic program, which is beyond our grasp for problems of more than 15 jobs. Our search for heuristic approaches led to the adoption of the Johnson sequence, which motivated two of the three approaches: dynamic programming and sequence-and-merge. The third approach, the greedy heuristic, was included as example of an elementary heuristic.

A Porter-SCOR modelling approach for the hospital supply chain

We suggest in this paper a modelling approach that extends the Analysis Specification Conception and Implementation (ASCI) methodology by putting the accent on the performance dimension. We suggest a value model as an extension of ASCI methodology based on Porters and SCOR models. We underline the necessity of defining an appropriate system of performance metrics that should be defined in accordance with the hospital value system. This extended methodology provides the user with a better understanding of the way the system works and enables to document practices and processes.

An application of a planning and scheduling multi-model approach in the chemical industry

In this paper, we are concerned with the production planning and scheduling of process industries. A real life application stems from the chemical industry where the production environment is subject to uncertainty, delays and interferences. We propose a multi-model based system for planning and scheduling in such a process industry. The multi-model system is defined as an architecture integrating expert system techniques, discrete event simulation, optimization algorithms and heuristics to support decision-making for complex production planning and scheduling problems. The system has been successfully tested and used to help in production planning and scheduling.

Assessing the impact of stochasticity for operating theater sizing

Over the last few decades, rational health care management and, in particular, operating theater planning, has attracted increased attention from practitioners and from the scientific community. However, although the operating theater environment is clearly stochastic, the impact of this randomness has often been ignored. In practice, simple rules based largely on past experience (such as keeping a safety margin), are most frequently used when making plans for the operating theater. In this paper, we propose an approach to help rationalize, at a strategic decision-making level, the way in which stochasticity can be taken into account in operating theater management, to help in the sizing and in the allocation of capacity. The three main sources of randomness are considered: durations of operations, unexpected emergencies and blocking because of a full recovery unit. Based on the Markov theory, our tool enables several performance measures to be estimated. An operating theater manager can use our approach to make informed decisions and assess, for example, the disruption of the planning by emergencies, the waiting times for emergency patients, the impact of the recovery unit, or the distribution of the working time. In particular, our approach helps determine the number of operations that should be planned in order to keep expected overtime limited. The tool is described in detail, discussed, and applied to the illustrative case of a Belgian hospital.

How stochasticity and emergencies disrupt the surgical schedule

In health care system, the operating theatre is recognized as having an important role, notably in terms of generated income and cost. Its management, and in particular its scheduling, is thus a critical activity, and has been the sub ject of many studies. However, the stochasticity of the operating theatre environment is rarely considered while it has considerable effect on the actual working of a surgical unit. In practice, the planners keep a safety margin, let’s say 15% of the capacity, in order to absorb the effect of unpredictable events. However, this safety margin is most often chosen sub jectively, from experience. In this paper, our goal is to rationalize this process. We want to give insights to managers in order to deal with the stochasticity of their environment, at a tactical–strategic decision level. For this, we propose an analytical approach that takes account of the stochastic operating times as well as the disruptions caused by emergency arrivals. From our model, various performance measures can be computed: the emergency disruption rate, the waiting time for an emergency, the distribution of the working time, the probability of overtime, the average overtime, etc. In particular, our tool is able to tell how many operations can be scheduled per day in order to keep the overtime limited.

Supply chain issues and opportunities

Advances in the development of new information and communication technologies coupled with the fierce competition have a deep impact on the development and positioning of current companies on international market places. To respond to the market changing conditions, firms have to rethink the layout of their supply chain, the management of their logistic systems and the development of partnership relations with their suppliers and customers. A firm can thus no longer be considered as an isolated entity but as a component of a wider supply network. Both academics and industrialists have been interested by different issues of this thematic. The International conference on Industrial Engineering and Production Management IEPM03, May 2003, Porto, focused on specific issues of the global supply chain with a special emphasis on logistics management and optimization. Participants had the possibility to identify emerging industrial issues and research opportunities in the area of Supply Chain Management. The papers presented in this special edition of the journal were selected among the best contributions discussed at the IEPM conference. They present substantial advances in the research on the supply chain in a wide variety of contexts and applications.

Implémentation d'une armoire automatique de dispensation des médicaments dans un hôpital : une méthodologie pour évaluer la performance

La mise en place d’une armoire automatique de gestion des médicaments change les pratiques en cours et requiert des investissements financiers. L’évaluation de ce nouveau système ne peut toutefois pas être envisagée d’un seul point de vue, qualité ou coûts et doit être pilotée par une politique adaptée de gestion des stocks. Pour mener cette étude, une version étendue de la méthodologie ASCI est utilisée pour analyser la situation existante, proposer et évaluer une solution en prenant en compte les points de vue des différentes parties prenantes de l’hôpital. En outre, un politique de gestion des stocks multi-produit, multi-niveau et contrainte par la capacité est appliquée pour piloter le nouveau système.