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Publicações

2019

Classification of local energy trading negotiation profiles using artificial neural networks

Autores
Pinto, A; Pinto, T; Praca, I; Vale, Z;

Publicação
IEEE Power and Energy Society General Meeting

Abstract
Electricity markets are evolving into a local trading setting, which makes it for unexperienced players to achieve good agreements and obtain profits. One of the solutions to deal with this issue is to provide players with decision support solutions capable of identifying opponents' negotiation profiles, so that negotiation strategies can be adapted to those profiles in order to reach the best possible results from negotiations. This paper presents an approach that classifies opponents' proposals during a negotiation, to determine which is the typical negotiation profile in which the opponent most relates. The classification process is performed using an artificial neural network approach, and it is able to adapt at each new proposal during the negotiation process, by re-classifying the opponents' negotiation profile according to the most recent actions. In this way, effective decision support is provided to market players, enabling them to adapt the negotiation strategy throughout the negotiations. © 2019 IEEE.

2019

RETHINKING THE USE OF SOFT MODES - BICYCLES: TOWARDS ENSURING SUSTAINABLE MOBILITY AND SOCIAL INNOVATION

Autores
Amaral, A; Barreto, L; Baltazar, S; Rocha, C;

Publicação
PROCEEDINGS OF THE 4TH INTERNATIONAL CONFERENCE ON ENERGY & ENVIRONMENT (ICEE 2019): BRINGING TOGETHER ENGINEERING AND ECONOMICS

Abstract
The modem societies claim on being safer, more sustainable and with more inclusive mobility policies, towards assuring the world sustainable standards. One of the key future mobility factors is focused on the usage of the soft modes, emphasizing the use of bicycles. This mean of transport needs to be permanently implemented worldwide, supported by policies that can unify user's, planners, public and private companies, academics and politicians. Therefore, it is crucial to understanding the user's motivations to adopt the bicycle as a mean of transport instead of the motorized vehicle solutions. With the aim of understanding the user's characteristics, needs and expectations regarding the use of bicycle, as well as to point out innovative initiatives and the role of bicycles in cities' planning, some European examples were analyzed and described as state-of-the-art practices. Such examples allow us to consider and propose a set of adjustments and future recommendations to strengthen the bicycle option as an effective mass mobility mean.

2019

Raster penetration map applied to the irregular packing problem

Autores
Sato, AK; Martins, TC; Gomes, AM; Guerra Tsuzuki, MSG;

Publicação
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

Abstract
Among the most complex problems in the field of 2-dimensional cutting & packing are irregular packing problems, in which items may have a more complex geometry. These problems are prominent in several areas, including, but not limited to, the textile, shipbuilding and leather industries. They consist in placing a set of items, whose geometry is often represented by simple polygons, into one or more containers such that there is no overlap between items and the utility rate of the container is maximized. In this work, the irregular strip packing problem, an irregular packing variant with a variable length container, is investigated. The placement space is reduced by adopting a rectangular grid and a full search is performed using preprocessed raster penetration maps to efficiently determine the new position of an item. Tests were performed using simple dotted board model cases and irregular strip packing benchmark instances. The comparison of our results with the state of the art solutions showed that the proposed algorithm is very competitive, achieving better or equal compaction in 9 out of 15 instances and improving the average density in 13 instances. Besides the contribution of the new best results, the proposed approach showed the advantage of adopting discrete placement, which can be potentially applied to other irregular packing problems.

2019

Assisting software engineering students in analyzing their performance in software development

Autores
Raza, M; Faria, JP; Salazar, R;

Publicação
SOFTWARE QUALITY JOURNAL

Abstract
Collecting product and process measures in software development projects, particularly in education and training environments, is important as a basis for assessing current performance and opportunities for improvement. However, analyzing the collected data manually is challenging because of the expertise required, the lack of benchmarks for comparison, the amount of data to analyze, and the time required to do the analysis. ProcessPAIR is a novel tool for automated performance analysis and improvement recommendation; based on a performance model calibrated from the performance data of many developers, it automatically identifies and ranks potential performance problems and root causes of individual developers. In education and training environments, it increases students' autonomy and reduces instructors' effort in grading and feedback. In this article, we present the results of a controlled experiment involving 61 software engineering master students, half of whom used ProcessPAIR in a Personal Software Process (PSP) performance analysis assignment, and the other half used a traditional PSP support tool (Process Dashboard) for performing the same assignment. The results show significant benefits in terms of students' satisfaction (average score of 4.78 in a 1-5 scale for ProcessPAIR users, against 3.81 for Process Dashboard users), quality of the analysis outcomes (average grades achieved of 88.1 in a 0-100 scale for ProcessPAIR users, against 82.5 for Process Dashboard users), and time required to do the analysis (average of 252 min for ProcessPAIR users, against 262 min for Process Dashboard users, but with much room for improvement).

2019

Fiber Microsphere Coupled in a Taper for a Large Curvature Range

Autores
Robalinho, P; Frazao, O;

Publicação
FIBERS

Abstract
This work consists of using an optical fiber microsphere as a sensor for a wide range of curvature radii. The microsphere was manufactured in a standard fiber with an electric arc. In order to maximize system efficiency, the microsphere was spliced in the center of a taper. This work revealed that the variations of the wavelength where the maxima and minima of the spectrum are located varies linearly with the curvature of the system with a maximum sensitive of 580 +/- 20 (pm km). This is because the direction of the input beam in the microsphere depends on the system curvature, giving rise to interferometric variations within the microsphere.

2019

GreenHub farmer: real-world data for Android energy mining

Autores
Matalonga, H; Cabral, B; Castor, F; Couto, M; Pereira, R; de Sousa, SM; Fernandes, JP;

Publicação
MSR

Abstract
As mobile devices are supporting more and more of our daily activities, it is vital to widen their battery up-time as much as possible. In fact, according to the Wall Street Journal, 9/10 users suffer from low battery anxiety. The goal of our work is to understand how Android usage, apps, operating systems, hardware and user habits influence battery lifespan. Our strategy is to collect anonymous raw data from devices all over the world, through a mobile app, build and analyze a large-scale dataset containing real-world, day-to-day data, representative of user practices. So far, the dataset we collected includes 12 million+ (anonymous) data samples, across 900+ device brands and 5.000+ models. And, it keeps growing. The data we collect, which is publicly available and by different channels, is sufficiently heterogeneous for supporting studies with a wide range of focuses and research goals, thus opening the opportunity to inform and reshape user habits, and even influence the development of both hardware and software for mobile devices.

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