Game engine for location-based services

Tese de mestrado integrado. Engenharia Informática e Computação. Universidade do Porto. Faculdade de Engenharia. 201

Context analysis in energy resource management residential buildings

This paper presents a context analysis methodology to improve the management of residential energy resources by making the decision making process adaptive to different contexts. A context analysis model is proposed and described, using a clustering process to group similar situations. Several clustering quality assessment indices, which support the decisions on how many clusters should be created in each run, are also considered, namely: the Calinski Harabasz, Davies Bouldin, Gap Value and Silhouette. Results show that the application of the proposed model allows to identify different contexts by finding patterns of devices' use and also to compare different optimal k criteria. The data used in this case study represents the energy consumption of a generic home during one year (2014) and features the measurements of several devices' consumption as well as of several contextual variables. The proposed method enhances the energy resource management through adaptation to different contexts.The present work was done and funded in the scope of the following projects: European Union's Horizon 2020 research and innovation programme, under the Marie Sklodowska-Curie grant agreement No 703689 (project ADAPT); EUREKA - ITEA2 Project M2MGrids (ITEA-13011), Project SIMOCE (ANI|P2020 17690), and has received funding from FEDER Funds through COMPETE program and from National Funds through FCT under the project UID/EEA/00760/2013info:eu-repo/semantics/publishedVersio

Leveraging RISC-V to build an open-source (hardware) OS framework for reconfigurable IoT devices

With the growing interest in RISC-V systems and the endless possi bilities of creating customized hardware architectures, we introduce the first proof of concept (PoC) implementation of ChamelIoT, the first open-source agnostic hardware operating system (OS) frame work for reconfigurable Internet of Things (IoT) low-end devices. At this stage, ChamelIoT, leveraging the Rocket Custom Co-Processor Interface (RoCC), provides hardware acceleration support for thread management and scheduling of three different OSes: RIOT, Zephyr, and FreeRTOS. This paper overviews the overall ChamelIoT archi tecture and describes the implementation details of the current PoC deployment. Our first experiments were carried out on a Xilinx Arty-35T FPGA Evaluation kit and the preliminary results are very promising, showing that the desired agnosticism and flexibility can be achieved with determinism and performance advantages at a reasonable cost of hardware resources

Viana de Lima: o ante-plano de urbanização de Bragança

O Ante-Plano de Urbanização de Bragança realizado por Viana de Lima (1913-1991), em 1963, surge em Portugal num período em que os princípios da Cidade Radiosa e da Carta de Atenas são determinantes no desenho da cidade, após serem insistentemente citados no I Congresso Nacional de Arquitectura de 1948. Constata-se a presença da linguagem arquitetónica de Le Corbusier (1887-1965) em quase toda a obra de Viana de Lima. Este facto, juntamente com a sua experiência de participação nos CIAM, liderando o grupo português que assiste a estes congressos, irão certamente influenciar a sua visão e abordagem urbanística. Embora numa situação periférica no enquadramento nacional, poderá Bragança ter vindo a corresponder à imagem de cidade moderna dos CIAM? Esta dissertação tem como objetivo confirmar neste ante-plano, a influência dos paradigmas da Cidade Radiosa e dos CIAM, assim como, perceber que síntese adaptativa dos seus princípios é feita no contexto desta cidade; ABSTRACT: VIANA DE LIMA: THE ANTE-PLAN OF URBANIZATION OF BRAGANÇA The Ante-Plan of Urbanization of Bragança carried out by Viana de Lima (1913-1991), in 1963, appears in Portugal at a time when the principles of the Radiant City and the Athens Charter are decisive in the design of the city, after being insistently cited in the I National Congress of Architects of 1948. The presence of the architectural language of Le Corbusier (1887-1965) in almost all the work of Viana de Lima is verified. This fact, along with the experience of participating in the CIAM, leading the Portuguese group attending these congresses, will certainly influence his vision and urban approach. Although in a peripheral situation within the national framework, could Bragança have come to correspond to the image of the modern city of CIAM? This dissertation aims to confirm in this ante-plan the influence of the paradigms of the Radiant City and the CIAM, as well as to realize which adaptive synthesis of its principles is done in the context of this city

Case based reasoning with expert system and swarm intelligence to determine energy reduction in buildings energy management

This paper proposes a novel Case Based Reasoning (CBR) application for intelligent management of energy resources in residential buildings. The proposed CBR approach enables analyzing the history of previous cases of energy reduction in buildings, and using them to provide a suggestion on the ideal level of energy reduction that should be applied in the consumption of houses. The innovations of the proposed CBR model are the application of the k-Nearest Neighbors algorithm (k-NN) clustering algorithm to identify similar past cases, the adaptation of Particle Swarm Optimization (PSO) meta-heuristic optimization method to optimize the choice of the variables that characterize each case, and the development of expert systems to adapt and refine the final solution. A case study is presented, which considers a knowledge base containing a set of scenarios obtained from the consumption of a residential building. In order to provide a response for a new case, the proposed CBR application selects the most similar cases and elaborates a response, which is provided to the SCADA House Intelligent Management (SHIM) system as input data. SHIM uses this specification to determine the loads that should be reduced in order to fulfill the reduction suggested by the CBR approach. Results show that the proposed approach is capable of suggesting the most adequate levels of reduction for the considered house, without compromising the comfort of the users.This work has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 641794 (project DREAMGO) and a grant agreement No 703689 (project ADAPT); and from FEDER Funds through COMPETE program and from National Funds through FCT under the project UID/EEA/00760/2013.info:eu-repo/semantics/publishedVersio

Operating systems for Internet of Things low-end devices: analysis and benchmarking

In the era of the Internet of Things (IoT), billions of wirelessly connected embedded devices rapidly became part of our daily lives. As a key tool for each Internet-enabled object, embedded operating systems (OSes) provide a set of services and abstractions which eases the development and speedups the deployment of IoT solutions at scale. This article starts by discussing the requirements of an IoT-enabled OS, taking into consideration the major concerns when developing solutions at the network edge, followed by a deep comparative analysis and benchmarking on Contiki-NG, RIOT, and Zephyr. Such OSes were considered as the best representative of their class considering the main key-points that best define an OS for resource-constrained IoT devices: low-power consumption, real-time capabilities, security awareness, interoperability, and connectivity. While evaluating each OS under different network conditions, the gathered results revealed distinct behaviors for each OS feature, mainly due to differences in kernel and network stack implementations.This work has been supported by national funds through FCT - Fundação para a Ciência e a Tecnologia within the Project Scope: UID/CEC/00319/2019

Performance comparison of a typical nonlinear load connected to Ac and Dc power grids

This paper presents a performance comparison of a typical nonlinear load used in domestic appliances (electronic load), when supplied by an ac and a dc voltage of the same rms value. The performance of the nonlinear load towards its connection to ac and dc power grids is accomplished in terms of the waveforms which are registered in the consumed current, internal dc-link voltage and output voltage. A simulation model was developed using realistic database models of the power semiconductors comprising a nonlinear load with input ac-dc converter, so that the efficiency can be calculated and compared for three distinct cases: (1) load supplied by an ac voltage; (2) load supplied by a dc voltage; (3) load without the input ac-dc converter supplied by a dc voltage. Thus, besides the comparison between the ac and dc power grids supplying the same nonlinear load (cases 1 and 2), a third case is considered, which consists of removing the input ac-dc converter (eliminating needless components of the nonlinear load when supplied by a dc voltage). The obtained results show that supplying nonlinear loads with dc power grids is advantageous in relation to the ac power grid, and therefore it can be beneficial to adapt nonlinear loads to be powered by dc power grids.This work has been supported by COMPETE: POCI-01-0145–FEDER–007043 and FCT –Fundação para a Ciência eTecnologia within the Project Scope: UID/CEC/00319/2013. This work is financed by the ERDF –European Regional De-velopment Fund through the Operational Programme for Competitiveness and Interna-tionalisation –COMPETE 2020 Programme, and by National Funds through the Por-tuguese funding agency, FCT –Fundação para a Ciência e a Tecnologia,within project SAICTPAC/0004/2015 –POCI –01–0145–FEDER–016434. Mr. Tiago Sousa is sup-ported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agency

Performance comparison of a typical nonlinear load supplied by ac and dc voltages

This paper presents a performance comparison of a typical nonlinear load when supplied by ac or dc voltages with the same rms value. The performance of the nonlinear load towards its connection to ac and dc power grids is accomplished in terms of the waveforms and efficiency. A simulation model was developed using realistic database models of the power semiconductors comprising the load, and an experimental setup was assembled, so that the efficiency can be determined and compared for simulation and real operating conditions. Three distinct cases were considered for this study: (1) Load supplied by ac voltage; (2) Load supplied by dc voltage; and (3) Load without the input ac-dc converter supplied by dc voltage. The obtained results show that supplying nonlinear loads with dc power grids is advantageous in relation to the ac power grid, and therefore it can be beneficial to adapt nonlinear loads to be powered by dc power grids.This work has been supported by COMPETE: POCI-01-0145–FEDER–007043 and FCT –Fundação para a Ciência e Tecnologiawithin the Project Scope: UID/CEC/00319/2013. This work is financed by the ERDF –European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation –COMPETE 2020 Programme, and by National Funds through thePortuguese funding agency, FCT –Fundação para a Ciência e a Tecnologia, within project SAICTPAC/0004/2015 –POCI –01–0145–FEDER–016434. Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agenc

A novel front-end multilevel converter for renewable energy systems in smart grids

The integration of renewable energy systems into smart grids requires dc-to-ac power electronics converters for adapting the voltage levels of both sides. In this context, a novel topology of front-end multilevel dc-to-ac converter is proposed in order to enhance the integration of renewable energy systems into smart grids, preventing power quality problems. The proposed converter is designed to operate as a grid-tied inverter, imposing controlled sinusoidal grid currents in phase opposition with the power grid voltage, and establishing five distinct voltage levels to improve the current waveform. The dc side is suitable to be connected directly to a set of photovoltaic solar panels with an appropriated voltage level, or to an external dc-to-dc intermediary converter used to interface other renewable energy sources. An entire analysis of the hardware design and the operation principle is presented, including the adopted control strategy for the proposed front-end converter in conditions of current control. An accurate computational validation under realistic operating conditions for a significant operating power range is presented using a dedicated power electronics simulation software, where the obtained results show the advantages and the convenience of the proposed front-end converter in detriment of the classical solutions.Fundação para a Ciência e Tecnologia (FCT); COMPETE: POCI-01-0145 –FEDER–007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work is financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation – COMPETE 2020 Programme, and by National Funds through the Portuguese funding agency, FCT – Fundação para a Ciência e a Tecnologia, within project SAICTPAC/0004/2015 – POCI – 01–0145– FEDER–016434info:eu-repo/semantics/publishedVersio