Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

2017

Residential MPC Controller Performance in a Household with PV Microgeneration

Authors
Silva, JMF; Godina, R; Rodrigues, EMG; Pouresmaeil, E; Catalao, JPS;

Publication
2017 IEEE MANCHESTER POWERTECH

Abstract
The energy demand of the residential sector and the adjacent option for fossil fuels has negative consequences by both greenhouse gases (GHG), CO2 and other air pollutants emissions. The home energy demand consists mainly of energy requirements for space and water heating along with the energy dedicated for appliances. Therefore, different strategies that aim to stimulate an efficient use of energy need to be reinforced at all levels of human activity. In this paper a comparison is made between a Model Predictive Control (MPC) model, the ON/OFF and proportional-integral-derivative (PID) control models of an air conditioning unit AC system controlling the temperature of a room. The model of the house with local Photovoltaic (PV) solar microgeneration is assumed to be located in a Portuguese city. The household of the case study is subject to the local solar irradiance, temperature and electricity tariff of a summer day.

2017

Optimum Design of Small-Scale Stand-Alone Hybrid Renewable Energy Systems

Authors
Lujano Rojas, JM; Dufo López, R; Bernal Agustín, JL; Osório, GJ; Catalão, JPS;

Publication
Optimization in Renewable Energy Systems: Recent Perspectives

Abstract
A crucial factor for the sustainable development of human society is access to electricity. This fact has motivated the development of renewable energy systems isolated or connected to the electric distribution network. Evaluation of autonomous hybrid energy systems from a technical and economic perspective is a difficult problem that requires using complex mathematical models of renewable sources and generators, such as photovoltaic (PV) panels and wind turbines, and the implementation of optimization techniques in order to obtain an economically successful design. This chapter describes and analyzes traditional isolated energy systems powered by solar PV and wind energies provided with a battery energy storage system. Simulation and optimization are illustrated through the analysis of a rural electrification project in Tangiers (Morocco) in order to provide electricity to rural clinic. Optimization analysis suggests the installation of a PV/BESS system due to the magnitude of the load to be supplied, operating costs, and environmental conditions.

2017

Fabry-Perot Sensor based on Two Coupled Microspheres for Strain Measurement

Authors
Monteiro, CS; Kobelke, J; Schuster, K; Bierlich, J; Frazao, O;

Publication
2017 25TH INTERNATIONAL CONFERENCE ON OPTICAL FIBER SENSORS (OFS)

Abstract
A Fabry-Perot based sensor with two coupled hollow microspheres is presented. The sensor was fabricated using fusion splicing techniques, enabling a low-cost, highly reproducible, production. The coupling of the two microspheres gives rise to a highly sensitive strain sensor, reaching a sensitivity of 4.07 pm/mu epsilon. The allsilica composition leads to a low thermal sensitivity, making the proposed structure suitable applications in environments with varying external conditions.

2017

Multi-agent Double Deep Q-Networks

Authors
Simoes, D; Lau, N; Reis, LP;

Publication
PROGRESS IN ARTIFICIAL INTELLIGENCE (EPIA 2017)

Abstract
There are many open issues and challenges in the multi-agent reward-based learning field. Theoretical convergence guarantees are lost, and the complexity of the action-space is also exponential to the amount of agents calculating their optimal joint-action. Function approximators, such as deep neural networks, have successfully been used in singleagent environments with high dimensional state-spaces. We propose the Multi-agent Double Deep Q-Networks algorithm, an extension of Deep Q-Networks to the multi-agent paradigm. Two common techniques of multi-agent Q-learning are used to formally describe our proposal, and are tested in a Foraging Task and a Pursuit Game. We also demonstrate how they can generalize to similar tasks and to larger teams, due to the strength of deep-learning techniques, and their viability for transfer learning approaches. With only a small fraction of the initial task's training, we adapt to longer tasks, and we accelerate the task completion by increasing the team size, thus empirically demonstrating a solution to the complexity issues of the multi-agent field.

2017

Recent Advances in Image Processing Techniques for Automated Harvesting Purposes: A Review

Authors
Pereira, CS; Morais, R; Reis, MJCS;

Publication
PROCEEDINGS OF THE 2017 INTELLIGENT SYSTEMS CONFERENCE (INTELLISYS)

Abstract
Image processing has been proved to be an effective tool for analysis in various human activity areas, namely, agricultural applications. Interpreting a digital color image of fruit orchard captured in field environment is extremely challenging due to adverse weather conditions, luminance variability and the presence of dust, insects and other unavoidable image noises. The purpose of this survey is to categorize and briefly review the literature on computer analysis of fruit images in agricultural operations, which comprises more than 60 papers published in the last 10 years. With the aim to perform applied research in agricultural imaging, this paper intends to focus on advanced image processing and analysis techniques used in applications for detection and classifications of fruits, developed in the last decade. For the reviewed techniques, some performance evaluation metrics achieved in various experiments are emphasized to help the researchers when making choices and develop new computer vision applications in fruit images.

2017

Model Trees

Authors
Torgo, L;

Publication
Encyclopedia of Machine Learning and Data Mining

Abstract

  • 2215
  • 4493