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Publications

2014

Reject option paradigm for the reduction of support vectors

Authors
Sousa, R; Da Rocha Neto, AR; Barreto, GA; Cardoso, JS; Coimbra, MT;

Publication
22nd European Symposium on Artificial Neural Networks, Computational Intelligence and Machine Learning, ESANN 2014 - Proceedings

Abstract
In this paper we introduce a new conceptualization for the reduction of the number of support vectors (SVs) for an efficient design of support vector machines. The techniques here presented provide a good balance between SVs reduction and generalization capability. Our proposal explores concepts from classification with reject option. These methods output a third class (the rejected instances) for a binary problem when a prediction cannot be given with sufficient confidence. Rejected instances along with misclassified ones are discarded from the original data to give rise to a classification problem that can be linearly solved. Our experimental study on two benchmark datasets show significant gains in terms of SVs reduction with competitive performances.

2014

LAYSTREAM: composing standard gossip protocols for live video streaming

Authors
Matos, M; Schiavoni, V; Riviere, E; Felber, P; Oliveira, R;

Publication
14-TH IEEE INTERNATIONAL CONFERENCE ON PEER-TO-PEER COMPUTING (P2P)

Abstract
Gossip-based live streaming is a popular topic, as attested by the vast literature on the subject. Despite the particular merits of each proposal, all need to implement and deal with common challenges such as membership management, topology construction and video packets dissemination. Well-principled gossip-based protocols have been proposed in the literature for each of these aspects. Our goal is to assess the feasibility of building a live streaming system, LAYSTREAM, as a composition of these existing protocols, to deploy the resulting system on real testbeds, and report on lessons learned in the process. Unlike previous evaluations conducted by simulations and considering each protocol independently, we use real deployments. We evaluate protocols both independently and as a layered composition, and unearth specific problems and challenges associated with deployment and composition. We discuss and present solutions for these, such as a novel topology construction mechanism able to cope with the specificities of a large-scale and delay-sensitive environment, but also with requirements from the upper layer. Our implementation and data are openly available to support experimental reproducibility.

2014

An adaptive control scheme for doubly fed induction generators - wind turbine implementation

Authors
Estahbanati, MJ;

Publication
JOURNAL OF EXPERIMENTAL & THEORETICAL ARTIFICIAL INTELLIGENCE

Abstract
This paper presents a new adaptive scheme for doubly fed induction generators (DFIGs) in order to augment their flexibility confronting with unpredicted operational conditions. Due to large fluctuations in the wind velocity, the proposed scheme would handle system unreliable operational conditions. In such system, which has multi-input, multi-output and is also represented as a nonlinear control system, the uncertain parameters would affect the operational conditions. So, in order to have a robust controlling scheme, the mentioned characteristics should be considered in the proposed method. The adaptive control scheme proposed in this paper satisfies the expected constraints and could also be implemented in real-world platforms, especially in large-scale wind farms with DFIG turbines. © 2014 Taylor & Francis.

2014

Managing Motivation at the Workplace through Negotiation

Authors
Carneiro, D; Novais, P; Zeleznikow, J; Andrade, F; Neves, J;

Publication
LEGAL KNOWLEDGE AND INFORMATION SYSTEMS

Abstract
Recent research shows that our performance and satisfaction at work depends more on motivational factors than the number of hours or the intensity of the work. In this paper we propose a framework aimed at managing motivation to improve workplace indicators. The key idea is to allow team managers and workers to negotiate over the conditions of the tasks so as to find the best motivation for the worker within the constraints of what the organization may offer.

2014

On the Automatic Normalization of Plaque Regions in Ultrasound Images of the Carotid

Authors
Rouco, J; Novo, J; Campilho, A; Campilho, A;

Publication
IMAGE ANALYSIS AND RECOGNITION, ICIAR 2014, PT II

Abstract
In order to assess the atherosclerotic plaque disruption risk from B-mode ultrasound images of the carotid, an appropriate normalization of the plaque regions is required. This is usually achieved through the manual selection of two sample regions in the image containing blood and adventitia tissues, which are used as reference. In this work, we propose a new plaque region normalization method that takes advantage of multiple blood and adventitia reference samples per image, and a method for the automatic selection of these reference samples. Several preliminary results are provided in order to demonstrate the possible capabilities of the proposed methods.

2014

Allocation of PEVs' Parking Lots in Renewable-Based Distribution System

Authors
Neyestani, N; Damavandi, MY; Shafie Khah, M; Catalao, JPS; Contreras, J;

Publication
2014 Australasian Universities Power Engineering Conference (AUPEC)

Abstract
Emerging trends in electric vehicles both in science and industry, as well as increasing popularity of these devices among end-users have laid serious issues in front of a system operator or planner. Higher deployment of available resources in the system will lead to higher flexibility for system operator in its interactions, besides to higher level of user satisfaction. In this study, various states of a 13 bus radial distribution network have been considered for allocation of Plug-in Electric Vehicles' (PEVs') parking lots. As Renewable Energy Resources (RERs) are becoming a main element of power systems, it is investigated how the future distribution network planning has to be organized by employing both RERs and PEV parking lots. Also, it is investigated how the allocation of parking lots varies in the system where these resources exist. Moreover, the costs and revenues obtained by the system operator in such systems are also studied.

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