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Publications

2016

Optimal Behavior of Electric Vehicle Parking Lots as Demand Response Aggregation Agents

Authors
Shafie khah, M; Heydarian Forushani, E; Osorio, GJ; Gil, FAS; Aghaei, J; Barani, M; Catalao, JPS;

Publication
IEEE TRANSACTIONS ON SMART GRID

Abstract
With increasing environmental concerns, the electrification of transportation plays an outstanding role in the sustainable development. In this context, plug-in electric vehicle (PEV) and demand response have indispensable impacts on the future smart grid. Since integration of PEVs into the grid is a key element to achieve sustainable energy systems, this paper presents the optimal behavior of PEV parking lots in the energy and reserve markets. To this end, a model is developed to derive optimal strategies of parking lots, as responsive demands, in both price-based and incentive-based demand response programs (DRPs). The proposed model reflects the impacts of different DRPs on the operational behavior of parking lots and optimizes the participation level of parking lots in each DRP. Uncertainties of PEVs and electricity market are also considered by using a stochastic programming approach. Numerical studies indicate that the PEV parking lots can benefit from the selective participation in DRPs.

2016

Call admission control for wireless mesh network based on power interference modeling using directional antenna

Authors
Kandasamy, S; Marques, C; Calçada, T; Ricardo, M; Matos, R; Sargento, S;

Publication
WIRELESS NETWORKS

Abstract
Interference is a fundamental issue in wireless mesh networks (WMNs) and it seriously affects the network performance. In this paper we characterize the power interference in IEEE 802.11 CSMA/CA based wireless mesh networks using directional antennas. A model based centralized call admission control (CAC) scheme is proposed which uses physical collision constraints, and transmitter-side, receiver-side and when-idle protocol collision prevention constraints. The CAC assists to manage requests from users depending on the available bandwidth in the network: when a new virtual link establishment request from a user is accepted into the network, resources such as interface, bandwidth, transmission power and channel are allocated in the participating nodes and released once the session is completed. The proposed CAC is also able to contain the interference in the WMN by managing the transmission power of nodes.

2016

Event detection from traffic tensors: A hybrid model

Authors
Fanaee, H; Gama, J;

Publication
NEUROCOMPUTING

Abstract
A traffic tensor or simply origin x destination x time is a new data model for conventional origin/destination (O/D) matrices. Tensor models are traffic data analysis techniques which use this new data model to improve performance. Tensors outperform other models because both temporal and spatial fluctuations of traffic patterns are simultaneously taken into account, obtaining results that follow a more natural pattern. Three major types of fluctuations can occur in traffic tensors: mutations to the overall traffic flows, alterations to the network topology and chaotic behaviors. How can we detect events in a system that is faced with all types of fluctuations during its life cycle? Our initial studies reveal that the current design of tensor models face some difficulties in dealing with such a realistic scenario. We propose a new hybrid tensor model called HTM that enhances the detection ability of tensor models by using a parallel tracking technique on the traffic's topology. However, tensor decomposition techniques such as Tucker, a key step for tensor models, require a complicated parameter that not only is difficult to choose but also affects the model's quality. We address this problem examining a recent technique called adjustable core size Tucker decomposition (ACS-Tucker). Experiments on simulated and real-world data sets from different domains versus several techniques indicate that the proposed model is effective and robust, therefore it constitutes a viable alternative for analysis of the traffic tensors.

2016

Management of surgery waiting lists in the Portuguese public healthcare network The information system for waiting list recovery programs

Authors
Reis, A; Reis, C; Morgado, L; Borges, J; Tavares, F; Goncalves, R; Guedes, M; Cruz, JB;

Publication
2016 11TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI)

Abstract
This paper presents the evolution of the process for management of surgery waiting lists in the Portuguese public hospital network. We use the perspective of the software development and deployment by UTAD, as a partner of the Ministry of Health, to create an information system to manage list recovery programs. We describe the early status and work, when data harvesting was the core challenge, up to the current automated situation. This paper bridges the PERLE, PPMA, PECLEC and SIGIC programmes, and concludes with lessons learned and suggestions for evolution of the process.

2016

Long-range trajectories from global and local motion representations

Authors
Pereira, EM; Cardoso, JS; Morla, R;

Publication
JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION

Abstract
Motion is a fundamental cue for scene analysis and human activity understanding in videos. It can be encoded in trajectories for tracking objects and for action recognition, or in form of flow to address behavior analysis in crowded scenes. Each approach can only be applied on limited scenarios. We propose a motion-based system that represents the spatial and temporal features of the flow in terms of I ong-range trajectories. The novelty resides on the system formulation, its generic approach to handle scene variability and motion variations, motion integration from local and global representations, and the resulting long-range trajectories that overcome trajectory-based approach problems. We report the results and conclusions that state its pertinence on different scenarios, comparing and correlating the extracted trajectories of individual pedestrians, manually annotated. We also propose an evaluation framework and stress the diverse system characteristics that can be used for human activity tasks, namely on motion segmentation.

2016

Signal reconstruction in the presence of side information: The impact of projection kernel design

Authors
Chen, MY; Renna, F; Rodrigues, MRD;

Publication
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings

Abstract
This paper investigates the impact of projection design on the reconstruction of high-dimensional signals from low-dimensional measurements in the presence of side information. In particular, we assume that both the signal of interest and the side information are described by a joint Gaussian mixture model (GMM) distribution. Sharp necessary and sufficient conditions on the number of measurements needed to guarantee that the average reconstruction error approaches zero in the low-noise regime are derived, for both cases when the side information is available at the decoder or at the decoder and encoder. Numerical results are also presented to showcase the impact of projection design on applications with real imaging data in the presence of side information. © 2016 IEEE.

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