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Publicações

2017

Identifying top relevant dates for implicit time sensitive queries

Autores
Campos, R; Dias, G; Jorge, AM; Nunes, C;

Publicação
INFORMATION RETRIEVAL JOURNAL

Abstract
Despite a clear improvement of search and retrieval temporal applications, current search engines are still mostly unaware of the temporal dimension. Indeed, in most cases, systems are limited to offering the user the chance to restrict the search to a particular time period or to simply rely on an explicitly specified time span. If the user is not explicit in his/her search intents (e.g., "philip seymour hoffman'') search engines may likely fail to present an overall historic perspective of the topic. In most such cases, they are limited to retrieving the most recent results. One possible solution to this shortcoming is to understand the different time periods of the query. In this context, most state-of-the-art methodologies consider any occurrence of temporal expressions in web documents and other web data as equally relevant to an implicit time sensitive query. To approach this problem in a more adequate manner, we propose in this paper the detection of relevant temporal expressions to the query. Unlike previous metadata and query log-based approaches, we show how to achieve this goal based on information extracted from document content. However, instead of simply focusing on the detection of the most obvious date we are also interested in retrieving the set of dates that are relevant to the query. Towards this goal, we define a general similarity measure that makes use of co-occurrences of words and years based on corpus statistics and a classification methodology that is able to identify the set of top relevant dates for a given implicit time sensitive query, while filtering out the non-relevant ones. Through extensive experimental evaluation, we mean to demonstrate that our approach offers promising results in the field of temporal information retrieval (T-IR), as demonstrated by the experiments conducted over several baselines on web corpora collections.

2017

Convolutional Bag of Words for Diabetic Retinopathy Detection from Eye Fundus Images

Autores
Costa, P; Campilho, A;

Publicação
PROCEEDINGS OF THE FIFTEENTH IAPR INTERNATIONAL CONFERENCE ON MACHINE VISION APPLICATIONS - MVA2017

Abstract
This paper describes a methodology for Diabetic Retinopathy detection from eye fundus images using a generalization of the Bag-of-Visual-Words (BoVW) method. We formulate the BoVW as two neural networks that can be trained jointly. Unlike the BoVW, our model is able to learn how to perform feature extraction, feature encoding and classification guided by the classification error. The model achieves 0.97 Area Under the Curve (AUC) on the DR2 dataset while the standard BoVW approach achieves 0.94 AUC. Also, it performs at the same level of the state-of-the-art on the Messidor dataset with 0.90 AUC.

2017

Sustainable desalinator - An EPS@ISEP 2016 project

Autores
Augustyns, L; Pogoda, M; Milesi, M; Kang, M; Valls, P; Duarte, A; Malheiro, B; Ferreira, F; Ribeiro, MC; Silva, MF; Ferreira, PD; Guedes, PB;

Publicação
Proceedings of the 45th SEFI Annual Conference 2017 - Education Excellence for Sustainability, SEFI 2017

Abstract
The European Project Semester (EPS) is a one semester capstone project/internship framework offered by the EPS providers to engineering, product design and business undergraduates. While a student-centred project-based learning offer, EPS proposes a unique multidisciplinary and multicultural teamwork set up to promote soft, technical and scientific competencies. In the spring of 2016, the EPS at the Instituto Superior de Engenharia do Porto (ISEP) welcomed a team of engineering students who chose to develop a sustainable water desalinator, the working principle relying on solar energy and natural temperature differences to convert saline water into fresh water. This paper describes the team's journey, including the motivation, the solution design process, considering the technical & scientific state of the art as well as the potential impact in terms of ethics, sustainability and marketing, and the development and testing of the prototype. The results obtained validate the purpose of the developed system since a significant reduction of the salt water conductivity, to values of the same order of magnitude of tap water, were observed. Although improvements can be made, the desalinator prototype produced 70 ml/d of distilled water in late spring and 7 ml/d in midwinter atmospheric conditions.

2017

BACK MATTER

Autores
Silva, MF; Virk, GS; Tokhi, MO; Malheiro, B; Guedes, P;

Publicação
Human-Centric Robotics

Abstract

2017

Interferometry Applications in All-Optical Communications Networks

Autores
Dionisio, RP;

Publicação
Optical Interferometry

Abstract

2017

Fabry-Perot cavity based on polymer FBG as refractive index sensor

Autores
Ferreira, MFS; Statkiewiez Barabach, G; Kowal, D; Mergo, P; Urbanczyk, W; Frazao, O;

Publicação
OPTICS COMMUNICATIONS

Abstract
The use of a polymer fiber as a refractive index sensor is proposed. A fiber Bragg grating is inscribed near the fiber tip and the fiber is cut shorter thus creating a Fabry-Perot cavity. The reflections between the fiber Bragg grating and the fiber end-face create a Fabry-Perot interferometer. The sensor was characterized to refractive index changes at constant temperature and to temperature at constant refractive index using a fast Fourier transform analysis of the interference signal. The sensor revealed a sensitivity of-1. 94 RIU-1 with a resolution of lx10(-3)RITJ and low sensitivity to temperature, with a cross sensitivity to temperature of 3. 6x10(-4)RIU/degrees C.

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