2016
Autores
Meneses, R; Brito, PQ; Gomes, PC;
Publicação
JOURNAL OF BUSINESS RESEARCH
Abstract
Portugal has become the second most expensive footwear brand manufacturer in the global market in just one decade. How does an offshore-outsourcing provider become a direct competitor with former clients? This study applies a fuzzy-set qualitative comparative analysis to 12 Portuguese footwear manufacturers and identifies the underlying factors of the managerial transition from an offshore-outsourcing provider to a direct brand manufacturer. The study finds that the transformation of external knowledge from the client into internal knowledge must occur first. But the decisive factor is the management's recognition that brand creation is a long-term investment and is less risky than remaining dependent on outsourcing. These findings contribute to the understanding of the transition to becoming a direct brand manufacturer.
2016
Autores
Santos, Joss; Albano, Michele; Lino Ferreira, Luis;
Publicação
INForum Simpósio de Informática
Abstract
The FlexOffer (FO) concept was initially created within the EU FP7 project
MIRABEL [1]. It permits exposing demand and supply loads with associated flexibilities
in time and quantity for energy commerce, load levelling, and different use-cases.
To put it in a simple way, a FO specifies an amount of energy, a duration, an earliest
begin time, a latest finish time, and a price, e.g., "I want 50 KWh over 3 hours between
5 PM and 12 PM, for a value of 0.25 €/kWh".
2016
Autores
Santos, G; Pinto, T; Praca, I; Vale, Z;
Publicação
ENERGY
Abstract
The electricity market sector has suffered massive changes in the last few decades. The worldwide electricity market restructuring has been conducted to potentiate the increase in competitiveness and thus decrease electricity prices. However, the complexity in this sector has grown significantly as well, with the emergence of several new types of players, interacting in a constantly changing environment. Several electricity market simulators have been introduced in recent years with the purpose of supporting operators, regulators, and the involved players in understanding and dealing with this complex environment. This paper presents a new, enhanced version of MASCEM (Multi-Agent System for Competitive Electricity Markets), an electricity market simulator with over ten years of existence, which had to be restructured in order to be able to face the highly demanding requirements that the decision support in this field requires. This restructuring optimizes the performance of MASCEM, both in results and execution time.
2016
Autores
Lujano Rojas, JM; Osorio, GJ; Catalao, JPS;
Publicação
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
Abstract
In this paper, a methodology to solve Unit Commitment (UC) problem from a probabilistic perspective is developed and illustrated. The method presented is based on solving the Economic Dispatch (ED) problem describing the Probability Distribution Function (PDF) of the output power of thermal generators, energy not supplied, excess of electricity, Generation Cost (GC), and Spinning Reserve (SR). The obtained ED solution is combined with Priority List (PL) method in order to solve UC problem probabilistically, giving especial attention to the probability of providing a determined amount of SR at each time step. Three case studies are analysed; the first case study explains how PDF of SR can be used as a metric to decide the amount of power that should be committed; while in the second and third case studies, two systems of 10-units and 110-units are analysed in order to evaluate the quality of the obtained solution from the proposed approach. Results are thoroughly compared to those offered by a stochastic programming approach based on mixed-integer linear programming formulation, observing a difference on GCs between 1.41% and 1.43% for the 10-units system, and between 3.75% and 4.5% for the 110-units system, depending on the chosen significance level of the probabilistic analysis.
2016
Autores
Jimenez, JF; Bekrar, A; Trentesaux, D; Leitao, P;
Publicação
SERVICE ORIENTATION IN HOLONIC AND MULTI-AGENT MANUFACTURING
Abstract
Dynamic hybrid control architectures are a powerful paradigm that addresses the challenges of achieving both performance optimality and operations reactivity in discrete systems. This approach presents a dynamic mechanism that changes the control solution subject to continuous environment changes. However, these changes might cause nervousness behaviour and the system might fail to reach a stabilized-state. This paper proposes a framework of a nervousness regulator that handles the nervousness behaviour based on the defined nervousness-state. An example of this regulator mechanism is applied to an emulation of a flexible manufacturing system located at the University of Valenciennes. The results show the need for a nervousness mechanism in dynamic hybrid control architectures and explore the idea of setting the regulator mechanism according to the nervousness behaviour state.
2016
Autores
Madeira, A; Neves, R; Martins, MA;
Publicação
JOURNAL OF LOGICAL AND ALGEBRAIC METHODS IN PROGRAMMING
Abstract
In the last decades, dynamic logics have been used in different domains as a suitable formalism to reason about and specify a wide range of systems. On the other hand, logics with many-valued semantics are emerging as an interesting tool to handle devices and scenarios where uncertainty is a prime concern. This paper contributes towards the combination of these two aspects through the development of a method for the systematic construction of many-valued dynamic logics. Technically, the method is parameterised by an action lattice that defines both the computational paradigm and the truth space (corresponding to the underlying Kleene algebra and residuated lattices, respectively).
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