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Publicações

Publicações por SYSTEM

2012

Spatial and commercial evolution of aviation networks: a case study in mainland Portugal

Autores
Jimenez, E; Claro, J; de Sousa, JP;

Publicação
JOURNAL OF TRANSPORT GEOGRAPHY

Abstract
This paper applies network analysis to study the evolution of aviation networks. It takes a different approach from previous research that usually only explores airline networks. The aviation network of the airports of Lisbon, Faro and Porto, is modelled using the supply of seats and the passenger demand between 2001 and 2010. This analysis is complemented with a study of the commercial evolution of the three airports. It is noticeable the impact of low-cost carriers in the evolution of the configuration of the network over time. A de-concentration effect is also shown to occur, due to the interaction between airport and airline decisions that favour network development. The results of the analysis highlight how critical it has become for airport managers to assess and satisfy the real requirements of the different types of airlines, in order to reduce uncertainty and increase traffic.

2012

A multiobjective metaheuristic for a mean-risk multistage capacity investment problem with process flexibility

Autores
Claro, J; de Sousa, JP;

Publicação
COMPUTERS & OPERATIONS RESEARCH

Abstract
In this paper, we propose a multiobjective local search metaheuristic for a mean-risk multistage capacity investment problem with process flexibility, irreversibility, lumpiness and economies of scale in capacity costs. In each period, discrete decisions concerning the investment in capacity expansion, and continuous decisions concerning the utilization of the available capacity to satisfy demand are considered. We solve the capacity utilization problems with linear programming, in order to find the minimum capacity for each resource with the other resources remaining unchanged, this way providing information on the feasibility of the discrete investment decisions. Conditional value-at-risk is considered as a risk measure. Results of a computational study are presented, that show the approach is capable of obtaining high-quality approximations to the efficient sets, with a modest computational effort.

2012

Regular and non-regular production scheduling of multipurpose batch plants

Autores
Moniz, S; Barbosa Povoa, AP; Sousa, JP;

Publicação
22 EUROPEAN SYMPOSIUM ON COMPUTER AIDED PROCESS ENGINEERING

Abstract
Regular and non-regular production can often be found in multipurpose batch plants, requiring two distinct operating strategies: campaign and short-term production. This paper describes a sequential approach for the simultaneous scheduling of campaign and short-term products in multipurpose batch plants. Campaign products follow a periodic scheduling and are constrained to a monthly demand and a safety stock level. Shortterm products have a non-periodic scheduling and must respect tight delivery time windows. Our integrated model is based on the Resource-Task Network (RTN) representation proposed by Pantelides (1994) and uses a discrete-time formulation.

2012

A negotiation approach to support conceptual agreements for ontology content

Autores
Pereira, C; Sousa, C; Soares, AL;

Publicação
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Abstract
Conceptualisation processes are pervasive to most technical and professional activities, but are seldom addressed explicitly due to the lack of theoretical and practical methods and tools. However, it seems not to be a popular research topic in knowledge representation or its sub-areas such as ontology engineering. The approach described in this paper is a contribution to the development of methods and tools to collaborative conceptualisation processes. The particularly challenging problem of conceptual negotiation is here tackled through a combination of ColBlend method and an argumentation-based strategy, creating an innovative method to conceptual negotiation, argile method. This method was implemented in to the ConceptME platform as an advanced negotiation mechanism. © 2012 Springer-Verlag.

2012

Collaborative Spaces as Mediators for Information Sharing in Collaborative Networks

Autores
Soares, AL; Alves, F;

Publicação
COLLABORATIVE NETWORKS IN THE INTERNET OF SERVICES

Abstract
Information and knowledge sharing within collaborative networks stills being a challenging problem. Particularly in self governed or mediated networks the information/collaboration deadlock is likely to occur if there are not instrumental methods, socially accepted, that foster usable and useful patterns of collaborative information management. This paper describes how the vision for a solution to this problem was developed using the design science frameworks and the concept of technological rules. The result is materialised in the concept collaborative spaces as pivoting collaborative structures in the network enabling locally shared information to feed the network global level.

2012

Information Management Barriers in Complex Research and Development Projects: An Exploratory Study on the Perceptions of Project Managers

Autores
Santos, VR; Soares, AL; Carvalho, JA;

Publicação
Knowledge and Process Management

Abstract
Many organizations depend on the success of rapidly deployed, limited time frame and multipartner projects as an important element of their business strategies. Information management is regarded as a critical and upmost important issue, especially in projects. Complex projects require additional team collaboration and a consistent information management strategy to support the development of the project. This paper reports the findings of an exploratory study on information management barriers in complex projects, particularly focusing issues and difficulties recognized by project participants and managers. Our study intends to fill the gap in empirical research regarding this subject and to provide new insights for project managers of complex projects to devise more effective information management strategies and tools to set up and run information technology platforms. © 2012 John Wiley & Sons, Ltd.

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