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Publications

2019

System-level study on impulse-radio integration-and-fire (IRIF) transceiver

Authors
Kianpour, I; Hussain, B; Mendonca, HS; Tavares, VG;

Publication
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS

Abstract
Integrate-and-fire (IFN) model of a biological neuron is an amplitude-to-time conversion technique that encodes information in the time-spacing between action potentials (spikes). In principle, this encoding scheme can be used to modulate signals in an impulse radio ultra wide-band (IR-UWB) transmitter, making it suitable for low-power applications, such as in wireless sensor networks (WSN) and biomedical monitoring. This paper then proposes an architecture based on IFN encoding method applied to a UWB transceiver scenario, referred to herein as impulse-radio integrate-and-fire (IRIF) transceiver, followed by a system-level study to attest its effectiveness. The transmitter is composed of an integrate-and-fire modulator, a digital controller and memory block, followed by a UWB pulse generator and filter. At the receiver side, a low-noise amplifier, a squarer, a low-pass filter and a comparator form an energy-detection receiver. A processor reconstructs the original signal at the receiver, and the quality of the synthesized signal is then verified in terms of effective number of bits (ENOB). Finally, a link budget is performed. (C) 2019 Published by Elsevier GmbH.

2019

Coordinating consumer-centric market and grid operation on distribution grid

Authors
Orlandini, T; Soares, T; Sousa, T; Pinson, P;

Publication
2019 16TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET (EEM)

Abstract
The increasing penetration of distributed energy resources, along with developments in house management systems, are supporting prosumers to play an active role in the electricity market. In particular, a peer-to-peer (P2P) electricity market is an attractive framework to allow direct transactions between prosumers. However, this may raise several challenges in the operation and management of the distribution grid. In this context, the main contribution of this paper is the design of P2P electricity markets taking into account grid characteristics while solving potential congestion and voltage problems. The paper proposes a coordination methodology between P2P markets and distribution system operator (DSO) allocating a grid tariff to the prosumers that cause grid limit violations. Such tariff is defined based on the euclidean distance among trading prosumers, which is implemented in the P2P market through product differentiation approach. The proposed methodology is compared to a benchmark model in a representative distribution grid with 138 nodes and 109 prosumers. An important conclusion is that the proposed methodology is capable of achieving a trade-off between prosumers P2P transactions and grid operation.

2019

Characterizing Bipolar Disorder-Associated Single Nucleotide Polymorphisms in a Large British Cohort Using Association Rules

Authors
Pinheira, A; Silva Dias, Rd; Nascimento, C; Dutra, I;

Publication
CIBB

Abstract
Bipolar Disorder (BD) is chronic and severe psychiatric illness presenting with mood alterations, including manic, hypomanic and depressive episodes. Due to the high clinical heterogeneity and lack of biological validation, both BD treatment and diagnostic are still problematic. Patients and clinicians would benefit from better clinical and biological characterization, ultimately opening a new possibility to distinct forms of treatment. In this context, we studied genome wide association (GWA) data from the Wellcome Trust Case Control Consortium (WTCCC). After an exploratory analysis, we found a higher prevalence of homozygous compared with heterozygous in different single nucleotide polymorphisms (SNPs) in genes previously associated with BD risk. Results from our association rules analysis indicate that there is a group of patients presenting with different groups of genotypes, including pairs or triples, while others present only one. We performed the same analysis with a control group from the same cohort (WTCCC) and found that although healthy subjects may present the same SNPs combinations, the risky alleles occur in a lower frequency. Moreover, no subject in the control group presented the same pairs or triples of genotypes found in the BD group, and if a pair or triple is found, the support and confidence are lower than in the BD group (< 50 %).

2019

Voltages in the network and inside industrial plants. Case of PSA-vigo

Authors
Pérez Donsión, M; Oliveira, FT;

Publication
Renewable Energy and Power Quality Journal

Abstract
The main objective of this paper consists in presenting a survey of voltage sags and short interruptions in different places along the geography of Galicia measured throughout two years. Effects and the possible solutions of the voltage sags and short interruptions in one industrial installation, PSA-Vigo, that produce cars, are also addressed. Finally, we will establish the corresponding conclusions.

2019

Moving from Waterfall to Agile: Perspectives from IT Portuguese Companies

Authors
Almeida, FL; Simões, J;

Publication
Int. J. Serv. Sci. Manag. Eng. Technol.

Abstract
This study investigates the main motivations, difficulties and good practices in the migration process of software development models from Waterfall to Agile experienced by IT Portuguese companies. For that, we adopted a quantitative methodology based on multiple case studies that allowed us to explore five research questions. In a first step, we propose to identify the main reasons that motivate the companies to adopt Agile development processes and we intend to characterize this migration process. We also explore a set of good practices that can be followed in this migration process and we suggest a set of measures that can be used to assess the success of projects in an Agile environment. Finally, we explore the organizational and management impacts with the introduction of Agile processes. Copyright © 2019, IGI Global.

2019

Multiobjective Congestion Management and Transmission Switching Ensuring System Reliability

Authors
Sheikh, M; Aghaei, J; Rajabdorri, M; Shafie khah, M; Lotfi, M; Javadi, MS; Catalao, JPS;

Publication
2019 IEEE INTERNATIONAL CONFERENCE ON ENVIRONMENT AND ELECTRICAL ENGINEERING AND 2019 IEEE INDUSTRIAL AND COMMERCIAL POWER SYSTEMS EUROPE (EEEIC / I&CPS EUROPE)

Abstract
Congestion in transmission lines is an important topic in power systems and it continues to be an area of active research. Various approaches have been proposed to mitigate congestion especially immediate ready ones such as Congestion Management (CM) and Transmission Switching (TS). Using either of the two or their combination (CMTS) may have undesirable consequences like increasing operational costs or increasing the number of switching of transmission lines. More switching aggravates system reliability and imposes extra costs on the operator. In this paper, a multi-objective model is introduced which reduces overall operation costs, the number of switching in transmission lines, and the congestion of lines, compared to available approaches which employ congestion management and TS simultaneously. To verify the performance of the proposed model, it is implemented using GAMS and tested on 6- and 118- bus IEEE test systems. A benders' decomposition approach was employed.

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