2017
Authors
Aparício, D; Ribeiro, P; Silva, F;
Publication
IEEE-ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS
Abstract
With recent advances in high-throughput cell biology, the amount of cellular biological data has grown drastically. Such data is often modeled as graphs (also called networks) and studying them can lead to new insights intomolecule-level organization. A possible way to understand their structure is by analyzing the smaller components that constitute them, namely network motifs and graphlets. Graphlets are particularly well suited to compare networks and to assess their level of similarity due to the rich topological information that they offer but are almost always used as small undirected graphs of up to five nodes, thus limiting their applicability in directed networks. However, a large set of interesting biological networks such asmetabolic, cell signaling, or transcriptional regulatory networks are intrinsically directional, and using metrics that ignore edge direction may gravely hinder information extraction. Our main purpose in this work is to extend the applicability of graphlets to directed networks by considering their edge direction, thus providing a powerful basis for the analysis of directed biological networks. We tested our approach on two network sets, one composed of synthetic graphs and another of real directed biological networks, and verified that they were more accurately grouped using directed graphlets than undirected graphlets. It is also evident that directed graphlets offer substantially more topological information than simple graph metrics such as degree distribution or reciprocity. However, enumerating graphlets in large networks is a computationally demanding task. Our implementation addresses this concern by using a state-of-the-art data structure, the g-trie, which is able to greatly reduce the necessary computation. We compared our tool to other state-of-the art methods and verified that it is the fastest general tool for graphlet counting.
2017
Authors
Pereira, MPS; Fitiwi, DZ; Santos, SF; Catalao, JPS;
Publication
2017 1ST IEEE INTERNATIONAL CONFERENCE ON ENVIRONMENT AND ELECTRICAL ENGINEERING AND 2017 17TH IEEE INDUSTRIAL AND COMMERCIAL POWER SYSTEMS EUROPE (EEEIC / I&CPS EUROPE)
Abstract
In the last decade, the level of variable renewable energy sources (RESs) integrated in distribution network systems have been continuously growing. This adds more uncertainty to the system, which also faces all traditional sources of uncertainty and those pertaining to other emerging technologies such as demand response and electric vehicles. As a result, distribution system operators are finding it increasingly difficult to maintain an optimal daily operation of such systems. Such challenges/limitations are expected to be alleviated when distribution systems undergo the transformation process to smart grids, equipped with appropriate technologies such as energy storage systems (ESSs) and switchable capacitor banks (SCBs). These technologies offer more flexibility in the system, allowing effective management of the uncertainty in RESs. This paper presents a stochastic mixed integer linear programming (SMILP) model, aiming to optimally operate distribution network systems, featuring variable renewables, and minimizing the impact of RES uncertainty on the system's overall performance via ESSs and SCBs. A standard 41-bus distribution system is employed to show the effectiveness of the proposed S-MILP model. Simulation results indicate that strategically placed ESSs and SCBs can substantially alleviate the negative impact of RES uncertainty in the considered system.
2017
Authors
van de Ven, P; O'Brien, H; Henriques, R; Klein, M; Msetfi, R; Nelson, J; Rocha, A; Ruwaard, J; O'Sullivan, D; Riper, H;
Publication
INTERNET INTERVENTIONS-THE APPLICATION OF INFORMATION TECHNOLOGY IN MENTAL AND BEHAVIOURAL HEALTH
Abstract
In this paper we introduce a new Android library, called ULTEMAT, for the delivery of ecological momentary assessments (EMAs) on mobile devices and we present its use in the MoodBuster app developed in the H2020 E-COMPARED project. We discuss context-aware, or event-based, triggers for the presentation of EMAs and discuss the potential they have to improve the effectiveness of mobile provision of mental health interventions as they allow for the delivery of assessments to the patients when and where these are most appropriate. Following this, we present the abilities of ULTEMAT to use such context-aware triggers to schedule EMAs and we discuss how a similar approach can be used for Ecological Momentary Interventions (EMIs).
2017
Authors
Murphy, A; Whelan, E; Bacciotti, F; Dougados, C; Ray, T; Coffey, D; Alcalá, J; Garcia, P; Comerón, F; Eislöffel, J;
Publication
Memorie della Societa Astronomica Italiana - Journal of the Italian Astronomical Society
Abstract
Here we present the first results from a MUSE/X-Shooter study of the jet from the classical T Tauri star TH 28. The combination of MUSE and X-Shooter enables us to take advantage of both spectro-imaging and broadband spectroscopy to comprehensively investigate the TH 28 jet. We present a MUSE spectro-image and PV plot of the Ha emission line and use flux ratios from the X-Shooter spectrum to estimate the mass accretion rate at log(?acc) = -9.4. Future work will focus on diagnostic analyses on both sets of data, including estimating the mass outflow rate (?out) and the extinction of the jet. © SAIt 2017.
2017
Authors
Alves, S; Fernández, M;
Publication
THEORETICAL COMPUTER SCIENCE
Abstract
We design a graph-based framework for the analysis of access control policies that aims at easing the specification and verification tasks for security administrators. We consider policies in the category-based access control model, which has been shown to subsume many of the most well known access control models (e.g., MAC, DAC, RBAC). Using a graphical representation of category-based policies, we show how answers to usual administrator queries can be automatically computed, and properties of access control policies checked. We show applications in the context of emergency situations, where our framework can be used to analyse the interaction between access control and emergency management.
2017
Authors
Maia, ACN; Jacobina, CB; de Freitas, NB; da Silva, IRFMP;
Publication
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
Abstract
This paper proposes and investigates a multilevel ac six-phase motor drive. The system is composed of five isolated three-leg voltage source inverters feeding the open-end windings of an asymmetrical six-phase induction motor (SPIM), which is adequate to generate multilevel voltages for high-power systems with voltage rating restrictions. A simple space vector pulse-width modulation (PWM) based on three similar individual planes and its implementation by means of equivalent level-shifted PWM are presented. A space vector pattern with a high number of voltage vectors redundancies is obtained. These redundancies and the application sequence of the voltage vectors are selected to minimize the amount of changes in the switching states and to decrease the harmonic distortion of the generated voltages. The vector pattern of this optimal modulation is obtained by analyzing only one plane and applied in the same way to the three planes as if they were independent. The developed PWM techniques have low computational complexity and are suitable for low-cost hardware implementations. Simulation results are used to compare the proposed topology with a conventional configuration in terms of harmonic distortion and semiconductor losses. Experimental results demonstrate the feasibility of the proposed drive system.
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