Abstract

Abstract
The need of a functional integration in the manufacturing area (Production, Quality, Maintenance), outlooking for a new manufacturing agility, causes the emergence of concerns with reliability, maintenance and security of the manufacturing equipments at the shop-floor. Several models and methodologies, encompassing technical, human, social and organisational aspects such as Total Preventive Maintenance (TPM) or Continuous Improvement (Kaizen), are today available to help in implementing new paradigms in this area. In this paper, we briefly relate our experiences in the development of a maintenance management information system in a shoes manufacturing company, highlighting the socio-organisational context influence on this development. This project was part of the ESPRIT project Real-I-CIM, aimed at providing low cost shop floor advanced management tools, inside an open and distributed architecture.

Abstract
In this article, we present the design and development of a localisation system for a mobile autonomous platform. The purpose of this system is to endow this vehicle with the capability of maintaining a position estimate in real time without artificial aids in a structured environment. Each position estimate is generated from the previous one with information obtained from the on board sensors as well as from the world model. Process and observation models are built in such a way that take into account the physical restrictions of the vehicle and its ultra-sonic sonars. All the stages of the Extended Kalman Filtering (EKF) process applied to the vehicle of interest are described. To increase the performance of the sonar data real time acquisition, a method based on entropy choosing the sonar observation in order to minimise the uncertainty of the position estimate is used. An adaptive process of matching the sonar observation decreasing the possibility of loss of the vehicle is also chosen. Satisfactory results showing the good performance of this localisation system are presented.

Abstract
In some formulations of the vehicle replacement problem, in particular those leading to repair limit type models, the alternative policies are evaluated and compared over a fixed planning horizon. Although it has been widely recognised that the optimal policies derived under these formulations depend critically on the length of the horizon, no method has been presented so far to set appropriately this parameter. In this paper. the authors describe a method which overcomes this shortcoming. Once the best policy has been derived from a given finite horizon with length H, such a policy is repeated indefinitely over time and an equivalent annual rent is computed. The parametrisation of H leads to the definition of an annual rent function with a sequence of nearly equidistant local minima. It is suggested that in practice the second local minimum of this function leads to an adequate choice of the parameter H. The method can be applied both to stochastic and deterministic cost modelling situations. The method was tested using both real data from large samples of different types of passenger vehicles and artificially generated data. (C) 1997 Elsevier Science B.V.

Abstract
Assortment selection problems with cutting policies play an important role in several industries but, possibly due to their combinatorial characteristics, they did not receive as much attention as cutting stock problems did, though the two problems are closely related. In this paper we graph several examples of cost functions of one and two-dimensional problems which reveal that many local optima with cost close to optimum exist. Several implementations of known meta-heuristics are tested with a real problem. Two different neighbourhood structures are considered and the different performance of the implemented heuristics is briefly discussed.

Abstract
This paper presents a reference position on the relation between manufacturing systems and work organisation strategies, It raises some issues and advances a methodological framework in the development of information/manufacturing systems and work organisation design methods. as to reach a balanced influence of the technology, organisation and people aspects in Complex Manufacturing Environments (CME). In this sense it is not presenting research results but, with the underlying goal of implementing a laboratory environment for the study of technical and or organisational developmental aspects of CMEs, there are overviewed the R&D requirements for an interdisciplinary approach involving Computer and Social Sciences. The main scientific areas analysed are Enterprise Integration and Work Organisation, focusing on the methodological aspects of each one.