The VOCAL Project (ESPRIT #23182):
Validation Of Constraint programming through an Application in Logistics


Some everyday tasks faced by industrial applications involve hard, highly combinatorial problems, like scheduling, resource allocation and planning. Their difficulty stems not only from their intrinsic complexity, but also from the need of being able to easily model them, and to quickly change them as the environment and the market conditions evolve, while ensuring the correctness of the model and its suitability for the goals of the company. These problems are difficult to address correctly using conventional programming techniques. Constraint Programming (CP) is an emerging technology which provides a general framework for efficient and flexible solving of complex problems, through combined implementation of various constraint solvers.


The VOCAL Trial Application aims at proving that CP technology can be exploited by companies from all industrial sectors, and that the resulting applications can be fully integrated within their corporate information system. This goal may be further divided into two main objectives: first, based on a logistic problem encountered by a large utility company, the CP technology will be introduced into their global information system through a local software development company, and will be used to solve it; second, the expertise acquired during the design, development and integration process will be used by the partners to improve the previous training seminars. This will produce a final result which, in the form of guidelines for industrial- oriented constraint programming and training seminars, will be used to disseminate the experience gained within the project to ease the introduction of CP technologies in other software companies.

The application dealt with in this project comes from the field of maintenance logistics for utility companies (more specifically for the distribution of electricity). The main problem is here to allocate the available resources (both human and technical) to the various maintenance operations to be performed on the network. In particular, the project will focus on the handling of planned preventive maintenance together with more urgent maintenance. CP is appropriate for the resolution of such problems, in particular since it provides a simple and general framework for the modelling of the application.

The project extends over an 18-months period. The work is divided into three major stages, following the CP development cycle: specifications of the application, design and prototyping, and integration.


The consortium is made of 4 partners: Iberdrola will act as the end-user, SAGE as the emerging technology user and software developer, PrologIA as technology provider, and UPM as consultant and leader of the training part of the project.


The results of the project will be exploited separately by the partners: Iberdrola's goal is to improve the organisation of their maintenance logistics, by introducing some decision-aid tools in their existing information system. SAGE's goal is to assess the relevance of the CP technology for the resolution of the problems of their clients, and to integrate it in their technological offer if the result is successful. PrologIA's goal is to get an assessment of their technology, and to get a practical experience of its introduction in a software development company. Finally, UPM's goal is to gain some further experience in the development of practical CP applications, to develop a training seminar suited to the needs of the industrial world, and to identify relevant future research problems as a result of user experiences with the technology.

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Last modified: Thu Dec 3 11:11:20 1998