2018
Autores
Fernandes, D; Ferreira, LS; Nozari, M; Sebastiao, P; Cercas, F; Dinis, R;
Publicação
2018 IEEE 29TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC)
Abstract
The constant need of operators to ensure a high quality of service requires an adequate estimation of signal level in the service area. Drive Tests (DTs) are used to monitor signal level. Still this is an expensive task, not being able to cover all areas. A methodology to build complete path loss grids for a given site is proposed. Starting from available DTs measurements for certain pixels, path loss is estimated for the remaining ones by tuning a propagation model and extrapolating the path loss for neighboring pixels. This allows to provide a complete path loss estimation for the desired area around the cell.
2018
Autores
Martins, M; Goncalves, R; Godinho, F; Novais, J;
Publicação
PROCEEDINGS OF THE 8TH INTERNATIONAL CONFERENCE ON SOFTWARE DEVELOPMENT AND TECHNOLOGIES FOR ENHANCING ACCESSIBILITY AND FIGHTING INFO-EXCLUSION (DSAI 2018)
Abstract
The legislation on the accessibility of the information and communication technologies (ICT) is not new and consequently there have been a number of international and national initiatives, however they are very focus in the Web. We are in the threshold of a more comprehensive approach in the ICT domain. The European Standard EN 301 549 specifies the accessibility requirements for public procurement of ICT products and services in Europe. This study focuses on the analysis of the benefits / impact, for each group of People with Special Needs (PSN), the parameters of the European Norms (EN) for ICT products and services, which support the new legislation in the domain of public acquisition for the countries of the European Union (EU), the EU Public Procurement Directive 2014/24/EU. Questions related to methodologies, techniques and tools to evaluate the parameters of these EN will be studied in the future, as well as the models for the certification of ICT products and services, with the purpose of presenting solutions. In the future, a framework will be also designed and developed with specific functionalities and being capable of assist and facilitate the evaluation of EN parameters, and consequently the certification of the ICT products and services.
2018
Autores
Satzger, G; Patrício, L; Zaki, M; Kühl, N; Hottum, P;
Publicação
Lecture Notes in Business Information Processing
Abstract
2018
Autores
Lezama, F; Soares, J; Faia, R; Pinto, T; Vale, Z;
Publicação
2018 IEEE Congress on Evolutionary Computation, CEC 2018 - Proceedings
Abstract
Power systems are showing a dynamic evolution in the last few years, caused in part by the adoption of smart grid technologies. The integration of new elements that represent a source of uncertainty, such as renewables generation, electric vehicles, variable loads and electricity markets, poses a higher degree of complexity causing that traditional mathematical formulations struggle in finding efficient solutions to problems in the smart grid context. In some situations, where traditional approaches fail, computational intelligence has demonstrated being a very powerful tool for solving optimization problems. In this paper, we analyze the application of Differential Evolution (DE) to address an energy resource management problem under uncertain environments. We perform a systematic parameter tuning to determine the best set of parameters of four state-of-the-art DE strategies. Having knowledge of the sensitivity of DE to the parameter selection, self-adaptive parameter control DE algorithms are also implemented, showing that competitive results can be achieved without the application of parameter tuning methodologies. Finally, a new hybrid-adaptive DE algorithm, HyDE, which uses a new 'DE/target - to - perturbed-best/1' strategy and an adaptive control parameter mechanism, is proposed to solve the problem. Results show that DE strategies with fixed parameters, despite very sensitive to the setting, can find better solutions than some adaptive DE versions. Overall, our HyDE algorithm excelled all the other tested algorithms, proving its effectiveness solving a smart grid application under uncertainty. © 2018 IEEE.
2018
Autores
Simab, M; Javadi, MS; Nezhad, AE;
Publicação
ENERGY
Abstract
The issue of environmental emissions has forced the power systems to use cleaner energy sources such as renewable and hydroelectric technologies. However, during recent decades due to the limitations on the available water in many regions, the optimal water reservoir usage has been highlighted. In this regard, this paper proposes a multi-objective model for short-term hydrothermal scheduling problem in the presence of the pumped-storage technology. It is noted that the framework well models the cascaded configuration of hydro reservoirs. Besides, in order to more accurately model the mentioned problem, a Mixed-Integer Non-Linear Programming (MINLP) optimization framework is presented. In this respect, the valve-loading effects occurred in thermal power generation technologies have been taken into account which turns the existing convex optimization problem into a non-convex one. In order to solve the mentioned problem, the Normal Boundary Intersection (NBI) method has been used while the VIKOR decision maker is employed to choose the most compromise solution amongst the Pareto optimal solutions obtained by NBI method. Finally, the efficiency of the proposed model has been verified through implementing four case studies and comparing the obtained results with those obtained by different methods. © 2017 Elsevier Ltd
2018
Autores
Nunes, S; Martins, J; Branco, F; Zolotov, M;
Publicação
Advances in Intelligent Systems and Computing
Abstract
The emergence and widespread use of Information and Communication Technologies enabled government agencies to develop their capacity for citizens interaction, hence providing better public services. These electronic services, typically known as e-Government, have been undergoing significant development over the last few years. Information technologies have become one of the central elements in electronic governance today, and probably they will outstand in the future too. Despite the clear advantages inherent in e-Government services usage, the interaction rate between citizens and governments is still low and considered to be unsatisfactory. In order to understand which determinants may influence and trigger the adoption of e-Government services by civil society, a research methodology consisting of a theory-based qualitative validation, has been defined. This validation is performed by an Online Focus Group, where several experts were involved with the goal of reaching a set of remarkable considerations about potential determinants that can influence the use of e-Government services. © 2018, Springer International Publishing AG, part of Springer Nature.
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