Alain Guinet

OPERATING THEATRE PLANNING

N patients must be planned in an operating theatre over a medium term horizon (one or two weeks). This operating theatre is composed of several operating rooms and of one recovery room where several beds are available. Each patient needs a particular surgical procedure, which defines the human (surgeon) and material (equipment) resources to use and the intervention duration. Additive characteristics must be taken into account: hospitalisation date, intervention deadline, etc. The patient satisfaction and resource efficiency are sought. These two criteria are, respectively, modelled by hospitalisation costs, i.e. the patient stay duration, and the overtime costs, i.e. the resource overloads. We propose to solve this problem in two steps. First, an operating theatre planning is defined. It consists in assigning patients to operating rooms over the horizon. Second, each loaded operating room is scheduled individually in order to synchronise the various human and material resources used. This paper focuses on the first step, i.e. the operating theatre planning, which defines a general assignment problem, i.e. a NP hard problem. In order to solve heuristically this problem, an assignment model with resource capacity and time-window additive constraints is proposed. Integrating most of the constraints in the cost objective function, an extension of the Hungarian method has been developed to calculate the operating theatre planning. This primal–dual heuristic has been successfully experimented on a wide range of problem test data.

Multi-site planning: A transshipment problem

Today, firms have to compete on international openness markets. The resulting production organisation is a multi-site production system. Several production units called sites have to supply irregular demands at the lower costs. We propose a two-level production management approach to control such systems. It results in a global multi-site production planning and in local multi-workshop scheduling. This paper focuses on the multi-site production planning problem. A primal–dual approach is proposed to solve this problem. It allows us to minimise variable and fixed costs. This heuristic has been experimented on a wide range of problem test data.

Modelling and simulation of emergency services with ARIS and Arena. Case study: the emergency department of Saint Joseph and Saint Luc Hospital

Overlong waiting time in emergency services is an important matter which has negative influence on healthcare quality. This problem can be resolved by improving emergency services using modelling and discrete event simulation of system process. In this article, a simulation model is designed to represent the patient visit process by using, respectively, IDS Scheer ARIS™ and Rockwell Arena™. This simulation model can help us to identify process bottlenecks, and adjust resources allocation or staff dimensioning without disturbing the actual system. For the purpose of reducing waiting time in emergency departments (ED), doctors efficiency improvement and quick pass process are proposed and experimented as two new solutions. In addition to simulation results, we summarise some advantages and shortcomings observed during our development work for future use of ARIS and Arena. This work was based on the ED at Saint Joseph and Saint Luc Hospital in Lyon, France.

Scheduling independent jobs on uniform parallel machines to minimize tardiness criteria

The problem of scheduling N jobs on M uniform parallel machines is studied. The objective is to minimize the mean tardiness or the weighted sum of tardiness with weights based on jobs, on periods or both. For the mean tardiness criteria in the preemptive case, this problem is NP-hard but good solutions can be calculated with a transportation problem algorithm. In the nonpreemptive case the problem is therefore NP-hard, except for the cases with equal job processing times or with job due dates equal to job processing times. No dominant heuristic is known in the general nonpreemptive case. The author has developed a heuristic to solve the nonpreemptive scheduling problem with unrelated job processing times. Initially, the algorithm calculates a basic solution. Next, it considers the interchanges of job subsets to equal processing time sum interchanging resources (i.e. a machine for a given period). This paper models the scheduling problem. It presents the heuristic and its result quality, solving 576 problems for 18 problem sizes. An application of school timetable scheduling illustrates the use of this heuristic.

Three stage no-idle flow-shops

The three stage no-idle flow-shop configuration, where machines work continuously without idle intervals, is an interesting manufacturing environment in many industries. Few researches have investigated this type of systems. The idle characteristic is a very strong constraint and it affects seriously the value of makespan (C max) criterion. We treat here the scheduling problem of three stage permutation flow-shop configuration with no-idle machines in order to minimise the makespan F3/no-idle/C max. An easily implementing heuristic is proposed to solve this problem with O(n log n) complexity. It finds optimal solutions for several cases. A computational study shows the result quality.

A travelling salesman approach to solve the F/no-idle/Cmax problem

This paper investigates the F =no-idle=Cmax problem, where machines work continuously without idle time intervals. The idle characteristic is a very strong constraint and it affects seriously the value of Cmax criterion. We treat here only the permutation flow-shop configuration for machine no-idle problems with the objective to minimise the makespan. Based on the idea that this problem can be modelled as a travelling salesman problem, an adaptation of the well-known nearest insertion rule is proposed to solve it. A computational study shows the result quality.

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.

Reduction of job-shop problems to flow-shop problems with precedence constraints

We study the problem of scheduling N independent jobs in a job-shop environment. Each job must be processed on M machines according to individual routes. The objective is to minimize the maximum completion time of the jobs. First, the job-shop problem is reduced to a flow-shop problem with job precedence constraints. Then, a set of flow-shop algorithms are modified to solve it. To evaluate the quality of these heuristics, several lower bounds on the optimal solution have been computed and compared with the heuristic solutions for 3040 problems. The heuristics appear especially promising for job-shop problems with ‘flow-like’ properties.

Traceability analysis and optimization method in food industry

Presented as the miracle solution to many food safety crises, traceability is a subject that has never been so topical. Crises, as for example the Bovine Spongiform Encephalopathy (BSE) crisis (from 1996), the chicken dioxin crisis (in May 1999) or the foot-and-mouth disease (in March 2001), created an awareness and a fear with the consumers who need to be reassured. The food companies, in front of this new problem, try to equip themselves with efficient traceability systems. Indeed, a badly administrated crisis can have catastrophic consequences for a company.

A Decision-Making Tool for Home Health Care Nurses' Planning

This article deals with problems encountered be routing nurses through home health care services. It is difficult to assign patients to different care workers by taking into account their availability and their skills. If patients need several cares during a week, they may be treated by the same employee. We show that this problem is equivalent to a routing problem with some specific constraints. We propose an integer linear program for deciding (1) which human resource should be used and (2) when to execute the service during the planning horizon in order to satisfy the care plan for each patient served by the home health care providers.