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Publicações

2016

On Using Temporal Networks to Analyze User Preferences Dynamics

Autores
Pereira, FSF; de Amo, S; Gama, J;

Publicação
DISCOVERY SCIENCE, (DS 2016)

Abstract
User preferences are fairly dynamic, since users tend to exploit a wide range of information and modify their tastes accordingly over time. Existing models and formulations are too constrained to capture the complexity of this underlying phenomenon. In this paper, we investigate the interplay between user preferences and social networks over time. We propose to analyze user preferences dynamics with his/her social network modeled as a temporal network. First, we define a temporal preference model for reasoning with preferences. Then, we use evolving centralities from temporal networks to link with preferences dynamics. Our results indicate that modeling Twitter as a temporal network is more appropriated for analyzing user preferences dynamics than using just snapshots of static network.

2016

Design and Implementation of the CloudMdsQL Multistore System

Autores
Kolev, B; Bondiombouy, C; Levchenko, O; Valduriez, P; Jimenez, R; Pau, R; Pereira, J;

Publicação
PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON CLOUD COMPUTING AND SERVICES SCIENCE, VOL 1 (CLOSER)

Abstract
The blooming of different cloud data management infrastructures has turned multistore systems to a major topic in the nowadays cloud landscape. In this paper, we give an overview of the design of a Cloud Multidatastore Query Language (CloudMdsQL), and the implementation of its query engine. CloudMdsQL is a functional SQL-like language, capable of querying multiple heterogeneous data stores (relational, NoSQL, HDFS) within a single query that can contain embedded invocations to each data store's native query interface. The major innovation is that a CloudMdsQL query can exploit the full power of local data stores, by simply allowing some local data store native queries (e.g. a breadth-first search query against a graph database) to be called as functions, and at the same time be optimized.

2016

A Survey on Computer Assisted Qualitative Data Analysis Software

Autores
Reis, LP; Costa, AP; de Souza, FN;

Publicação
2016 11TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI)

Abstract
Computer Assisted Qualitative Data Analysis Software (CAQDAS) may be defined as tools that help researchers developing qualitative research projects. These software packages help the users with tasks such as transcription analysis, writing and annotation, coding and text interpretation, recursive abstraction, content search and analysis, discourse analysis, data mapping, grounded theory methodology, among several other types of analysis. This paper surveys the most relevant CAQDAS software packages comparing their features on different areas such as data management and organization, data annotation, search and query capacities, data visualization, import/export potentialities and teamwork/collaborative work features.

2016

Architecture of computing systems – ARCS 2016: 29th international conference Nuremberg, Germany, April 4-7, 2016 Proceedings

Autores
Hannig, F; Cardoso, JMP; Pionteck, T; Fey, D; Preikschat, WS; Teich, J;

Publicação
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Abstract

2016

Data mining with R: Learning with case studies, second edition

Autores
Torgo, L;

Publicação
Data Mining with R: Learning with Case Studies, Second Edition

Abstract
Data Mining with R: Learning with Case Studies, Second Edition uses practical examples to illustrate the power of R and data mining. Providing an extensive update to the best-selling first edition, this new edition is divided into two parts. The first part will feature introductory material, including a new chapter that provides an introduction to data mining, to complement the already existing introduction to R. The second part includes case studies, and the new edition strongly revises the R code of the case studies making it more up-to-date with recent packages that have emerged in R. The book does not assume any prior knowledge about R. Readers who are new to R and data mining should be able to follow the case studies, and they are designed to be self-contained so the reader can start anywhere in the document. The book is accompanied by a set of freely available R source files that can be obtained at the book's web site. These files include all the code used in the case studies, and they facilitate the "do-it-yourself" approach followed in the book. Designed for users of data analysis tools, as well as researchers and developers, the book should be useful for anyone interested in entering the "world" of R and data mining.

2016

Assessment of Robotic Picking Operations Using a 6 Axis Force/Torque Sensor

Autores
Moreira, E; Rocha, LF; Pinto, AM; Moreira, AP; Veiga, G;

Publicação
IEEE ROBOTICS AND AUTOMATION LETTERS

Abstract
This letter presents a novel architecture for evaluating the success of picking operations that are executed by industrial robots. It is formed by a cascade of machine learning algorithms (kNN and SVM) and uses information obtained by a 6 axis force/torque sensor and, if available, information from the built-in sensors of the robotic gripper. Beyond measuring the success or failure of the entire operation, this architecture makes it possible to detect in real-time when an object is slipping during the picking. Therefore, force and torque signatures are collected during the picking movement of the robot, which is decomposed into five different stages that allows to characterize distinct levels of success over time. Several trials were performed using an industrial robot with two different grippers for picking a long and flexible object. The experiments demonstrate the reliability of the proposed approach under different picking scenarios since, it obtained a testing performance (in terms of accuracy) up to 99.5% of successful identification of the result of the picking operations, considering an universe of 400 attempts.

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