2015
Autores
Teodoro, A; Duarte, L; Sillero, N; Goncalves, JA; Fonte, J; Goncalves Seco, L; Pinheiro da Luze, LMP; dos Santos Beja, NMRD;
Publicação
EARTH RESOURCES AND ENVIRONMENTAL REMOTE SENSING/GIS APPLICATIONS VI
Abstract
Herdade da Contenda (HC), located in Moura municipality, Beja district (Alentejo province) in the south of Portugal (southwestern Iberia Peninsula), is a national hunting area with 5270ha. The development of an integrated system that aims to make the management of the natural and cultural heritage resources will be very useful for an effective management of this area. This integrated system should include the physical characterization of the territory, natural conservation, land use and land management themes, as well the cultural heritage resources. This paper presents a new tool for an integrated environmental management system of the HC, which aims to produce maps under a GIS open source environment (QGIS). The application is composed by a single button which opens a window. The window is composed by twelve menus (File, DRASTIC, Forest Fire Risk, Revised Universal Soil Loss Equation (RUSLE), Bioclimatic Index, Cultural Heritage, Fauna and Flora, Ortofoto, Normalizes Difference Vegetation Index (NDVI), Digital Elevation Model (DEM), Land Use Land Cover Cover (LULC) and Help. Several inputs are requires to generate these maps, e.g. DEM, geologic information, soil map, hydraulic conductivity information, LULC map, vulnerability and economic information, NDVI. Six buttons were added to the toolbar which allows to manipulate the information in the map canvas: Zoom in, Zoom out, Pan, Print/Layout and Clear. This integrated and open source GIS environment management system was developed for the HC area, but could be easily adapted to other natural or protected area. Despite the lack of data, the methodology presented fulfills the objectives.
2015
Autores
Queirós, Ricardo; Simões, Alberto;
Publicação
Abstract
2015
Autores
Lopes, S; Fontes, FACC;
Publicação
2007 European Control Conference, ECC 2007
Abstract
The main purpose of necessary conditions of optimality (NCO) is to identify a 'small' set of candidates to minimizers among the overall set of admissible solutions. However, for certain optimal control problems with state constraints, it might happen that the set of all admissible solutions coincides with the set of candidates satisfying the NCO. This phenomenon is known as the degeneracy phenomenon and there has been some literature proposing stronger forms of NCO that can be informative in such cases: The so-called nondegenerate NCO. The nondegenerate NCO proposed here are valid under a different set of hypothesis and under a constraint qualification of an integral-type that, in relation to some previous literature, is easier to verify. © 2007 EUCA.
2015
Autores
Monteiro Pereira, RMM; Machado Ferreira, CMM; Maciel Barbosa, FPM;
Publicação
2015 50TH INTERNATIONAL UNIVERSITIES POWER ENGINEERING CONFERENCE (UPEC)
Abstract
Nowadays, the large penetration of wind power generation poses new challenges for dynamic voltage stability analysis of an electric power system. The practical importance of dynamic voltage stability analysis is to help in designing and selecting counter-measures in order to avoid voltage collapse and enhance system stability. The impact of wind integration on reactive reserve requirements is a current area of interest for renewable integration studies and power system operators. In this paper is studied a new wind power plant model with reactive power management. The active power and the frequency management are taken into account too. The developed model can be used to represent, in a simplified way, an entire wind farm in order to simulate the dynamic voltage stability of the system, whatever the technology involved in the wind turbine. The system is completely modelled by a single dynamic converter model with appropriate control loops intended to reproduce the overall response of a wind farm for different grid events, such as faults or voltage and reactive power management at the point of common coupling.
2015
Autores
Strasser, T; Andren, F; Kathan, J; Cecati, C; Buccella, C; Siano, P; Leitao, P; Zhabelova, G; Vyatkin, V; Vrba, P; Marik, V;
Publicação
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
Abstract
Renewable energy sources are one key enabler to decrease greenhouse gas emissions and to cope with the anthropogenic climate change. Their intermittent behavior and limited storage capabilities present a new challenge to power system operators to maintain power quality and reliability. Additional technical complexity arises from the large number of small distributed generation units and their allocation within the power system. Market liberalization and changing regulatory framework lead to additional organizational complexity. As a result, the design and operation of the future electric energy system have to be redefined. Sophisticated information and communication architectures, automation concepts, and control approaches are necessary in order to manage the higher complexity of so-called smart grids. This paper provides an overview of the state of the art and recent developments enabling higher intelligence in future smart grids. The integration of renewable sources and storage systems into the power grids is analyzed. Energy management and demand response methods and important automation paradigms and domain standards are also reviewed.
2015
Autores
Moutinho, J; Freitas, D; Araújo, RE;
Publicação
2015 IEEE 18TH INTERNATIONAL CONFERENCE ON COMPUTATIONAL SCIENCE AND ENGINEERING (CSE)
Abstract
This paper presents the results of an indoor localization experiment that uses spread spectrum modulated audio signals. Indoor spaces do not have line-of-sight to global navigation satellite systems and do not have a truly universal localization system to allow mobile devices to localize themselves. Previous approaches focused in using custom made hardware with several types of signals that, even though with good performance, are not feasible to adopt in a wide scale utilization. The proposed approach uses pre-existent off-the-shelf hardware and easy to handle audio signals present in our everyday lives. However, the challenges when using audible and very susceptible to multipath types of signals are many and require validation of the subjacent principles. An experiment in a real indoor environment was conducted to estimate localization while using spread spectrum noise like signals barely perceptible to people. Results demonstrated a 1.3 cm average accuracy in the center area. These and other results demonstrate the possibility of the use of audio signals with all the advantages regarding wide scale dissemination of an indoor localization solution.
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