2006
Authors
De Magalhaes, JM; De Sousa, JP;
Publication
Central European Journal of Operations Research
Abstract
In recent years, the pharmaceutical sector has gone through deep changes, partially due to the ageing of the population and to the increasing of costs in health care services. With margins that are getting lower and lower, the drug distribution problem to pharmacies has become much more important, particularly in large metropolitan areas. As pharmacies demand shorter delivery times, vehicle routing and scheduling problems become harder for distributors. It is recognized that the traditional system based on fixed routes does not fulfil the expectations of pharmacies and may, in some cases, be quite inefficient for distributiors. In this work, a case study has been carried out and a change of the traditional approach is proposed, by adopting a system of variable routes that are dynamically designed, based on orders that are constantly arriving along the day. A dynamic algorithm is therefore proposed, meant to be run several times a day. It has four phases: first, a clustering of the orders is performed; second, potential routes are constructed; third, a route is selected for operation; and finally, that route is subject to an improvement process. The selection of the next route to be launched may be postponed in order to take advantage of subsequent information. The algorithm has been tested in the case study, by simulating one week of operation, and by comparing the results with the plan produced by the traditional way. © Springer-Verlag 2006.
2005
Authors
Crispim, JA; Sousa, JP;
Publication
Collaborative Networks and Their Breeding Environments
Abstract
In this paper we present a Decision Support System (DSS) to deal with the partner selection problem taking place in the formation or re-organization of a Virtual Enterprise (VE). This DSS is based on a multi-criteria model and handles several types of data (numerical, interval, linguistic and binary). This approach is used to facilitate the expression of the decision maker's preferences and assessments about the potential partners and can be performed individually or by group. The system also allows the assignment of a degree of confidence to each linguistic statement. the operation of the DSS is structured in two phases. In the first phase it determines the set of non-dominated alternatives (potential VEs) through the use of meta-heuristics. The second phase ranks the alternatives for a possible network of enterprises configuring the VE. This is achieved through a procedure based on linguistic analysis and distance measures.
2002
Authors
Soares, AL; de Sousa, JP;
Publication
COLLABORATIVE BUSINESS ECOSYSTEMS AND VIRTUAL ENTERPRISES
Abstract
This paper proposes a first version of a conceptual framework based on Social Actors Networks (SAN) to support the process of creation and configuration of Networked and Virtual Enterprises (N/VE). The concept of SAN is explained and applied in the context of N/VE, highlighting the potential benefits in the analysis and specification of agent based information systems. This approach is partially being tested in a distributed Decision Support System, designed around a flexible and robust agent-based information system architecture.
2004
Authors
Soares, AL; de Sousa, JP; Barbedo, F;
Publication
PROCESSES AND FOUNDATIONS FOR VIRTUAL ORGANIZATIONS
Abstract
Collaborative Networks (CN) and Virtual Organisations (VO) can partially be modelled by using Graph Theory, as a natural framework for describing relationships, interactions and collaboration. Our work aims at extending and integrating results from that theory and other different fields and scientific disciplines, to enable modelling complex and non tangible factors, dynamics, trade-offs between individual and common objectives, arising in the set-up and management of VO. As a way to handle these issues in a holistic way, we present extensions of Social Actors Networks that are able to encompass various, complementary perspectives in dealing with VO, and coping with the different phases of its life cycle. Current results seem promising in the direction of creating a sound frame work for modelling and supporting holistic process management in Collaborative Networks. For illustration purposes a simple case study is briefly sketched and some findings presented. Finally sortie open issues are surveyed and lines for future research identified.
1998
Authors
Bastos, JA; Sousa, JP;
Publication
GLOBALIZATION OF MANUFACTURING IN THE DIGITAL COMMUNICATIONS ERA OF THE 21ST CENTURY: INNOVATION, AGILITY, AND THE VIRTUAL ENTERPRISE
Abstract
The purpose of this paper is to present a new view on the problem of capacity planning in a distributed network of enterprises, i.e. in a Virtual Enterprise (VE). This view is based on a distributed planning architecture, that takes into account the requirements and characteristics of local capacity models. In order to cope with the new emerging problems that the VE are encountering, we have been designing and investigating two generic architectures of Decision Support Systems (DSS) for VE planning with capacity checking, applicable to different scenarios of distributed networks of enterprises. The first architecture is hierarchical and is based on the existence of a global decision-maker. The second one is fully distributed and is based in a multi-agent co-operative environment. This work is part of a broader project with a particular focus on the semiconductor industry.
1995
Authors
CARRAVILLA, MA; DESOUSA, JP;
Publication
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH
Abstract
In this paper, we analyse a complex production planning problem in a Make-To-Order company, involving quoting due dates, along with production scheduling, some plant layout decisions and line balancing issues. A general framework has been developed that identifies the main levels for decision making, and tackles these problems in a hierarchical fashion, the resulting interactions being carefully taken into consideration. This framework, based on considering discretised planning horizons, is implemented on a Decision Support System developed around an interface specially designed to involve the various participants in the planning process. In practice, the system is composed by a package of software products used as add-ons to the main management information system of the company. A comprehensive and detailed description of the approach, techniques used and developed algorithms is presented. The experience in using a first prototype of the system shows this may become a highly valuable computer tool in production planning, layout design and assignment of orders.
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