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

2018

Bridging Automation and Robotics: an Interprocess Communication between IEC 61131-3 and ROS

Authors
Pinto, T; Arrais, R; Veiga, G;

Publication
2018 IEEE 16TH INTERNATIONAL CONFERENCE ON INDUSTRIAL INFORMATICS (INDIN)

Abstract
The contemporary adoption of Cyber-Physical Systems and improvements in robotic applications in industrial scenarios demands for horizontal integration mechanisms with already existing automation equipment, controlled by PLCs. This paper aims to shorten the gap between the automation and robotics domain, by proposing an Interprocess Communication method to establish interoperability between robotic systems and automation equipment in a reliable and straightforward manner. In particular, this paper introduces a novel approach for linking ROS and IEC 61131-3 by way of shared memory interfaces, enabling and promoting their interactions. Moreover, this paper addresses the applied synchronization mechanism for handling concurrent accesses to the shared memory location, explores data type mapping between ROS and IEC 61131-3, and identifies some practical industrial applications.

2018

Dynamic electricity tariff definition based on market price, consumption and renewable generation patterns

Authors
Ribeiro, C; Pinto, T; Faria, P; Ramos, S; Vale, Z; Baptista, J; Soares, J; Navarro Caceres, M; Corchado, JM;

Publication
2018 CLEMSON UNIVERSITY POWER SYSTEMS CONFERENCE (PSC)

Abstract
The increasing use of renewable energy sources and distributed generation brought deep changes in power systems, namely with the operation of competitive electricity markets. With the eminent implementation of micro grids and smart grids, new business models able to cope with the new opportunities are being developed. Virtual Power Players are a new type of player, which allows aggregating a diversity of entities, e.g. generation, storage, electric vehicles, and consumers, to facilitate their participation in the electricity markets and to provide a set of new services promoting generation and consumption efficiency, while improving players' benefits. In order to achieve this objective, it is necessary to define tariff structures that benefit or penalize agents according to their behavior. In this paper a method for determining the tariff structures has been proposed, optimized for different load regimes. Daily dynamic tariff structures were defined and proposed, on an hourly basis, 24 hours day-ahead from the characterization of the typical load profile, the value of the electricity market price and considering the renewable energy production.

2018

Using Metalearning for Parameter Tuning in Neural Networks

Authors
Felix, C; Soares, C; Jorge, A; Ferreira, H;

Publication
VIPIMAGE 2017

Abstract
Neural networks have been applied as a machine learning tool in many different areas. Recently, they have gained increased attention with what is now called deep learning. Neural networks algorithms have several parameters that need to be tuned in order to maximize performance. The definition of these parameters can be a difficult, extensive and time consuming task, even for expert users. One approach that has been successfully used for algorithm and parameter selection is metalearning. Metalearning consists in using machine learning algorithm on (meta)data from machine learning experiments to map the characteristics of the data with the performance of the algorithms. In this paper we study how a metalearning approach can be used to obtain a good set of parameters to learn a neural network for a given new dataset. Our results indicate that with metalearning we can successfully learn classifiers from past learning tasks that are able to define appropriate parameters.

2018

Load forecasting through functional clustering and ensemble learning

Authors
Rodrigues, F; Trindade, A;

Publication
KNOWLEDGE AND INFORMATION SYSTEMS

Abstract
In this paper a load forecasting methodology for 2days-ahead based on functional clustering and on ensemble learning is presented. Due to the longitudinal nature of the load diagrams, these are segmented using a functional clustering procedure to group together similar daily load curves concerning its phase and amplitude. Next, ensemble learning of extreme learning machine models, developed for several load curves groups, is made to fully integrate the advantages of all models and improve the accuracy of the final load forecasting. The quality of this methodology is illustrated with a real case study concerning load consumption patterns of clients with different economic activities from a Portuguese energy trading company. The forecasting results for 2days-ahead are good for practical use, yielding a R-2 = 0.967.

2018

A Text Feature Based Automatic Keyword Extraction Method for Single Documents

Authors
Campos, R; Mangaravite, V; Pasquali, A; Jorge, AM; Nunes, C; Jatowt, A;

Publication
ADVANCES IN INFORMATION RETRIEVAL (ECIR 2018)

Abstract
In this work, we propose a lightweight approach for keyword extraction and ranking based on an unsupervised methodology to select the most important keywords of a single document. To understand the merits of our proposal, we compare it against RAKE, TextRank and SingleRank methods (three well-known unsupervised approaches) and the baseline TF. IDF, over four different collections to illustrate the generality of our approach. The experimental results suggest that extracting keywords from documents using our method results in a superior effectiveness when compared to similar approaches.

2018

Human-Robot Interaction Based on Gestures for Service Robots

Authors
de Sousa, P; Esteves, T; Campos, D; Duarte, F; Santos, J; Leao, J; Xavier, J; de Matos, L; Camarneiro, M; Penas, M; Miranda, M; Silva, R; Neves, AJR; Teixeira, L;

Publication
VIPIMAGE 2017

Abstract
Gesture recognition is very important for Human-Robot Interfaces. In this paper, we present a novel depth based method for gesture recognition to improve the interaction of a service robot autonomous shopping cart, mostly used by reduced mobility people. In the proposed solution, the identification of the user is already implemented by the software present on the robot where a bounding box focusing on the user is extracted. Based on the analysis of the depth histogram, the distance from the user to the robot is calculated and the user is segmented using from the background. Then, a region growing algorithm is applied to delete all other objects in the image. We apply again a threshold technique to the original image, to obtain all the objects in front of the user. Intercepting the threshold based segmentation result with the region growing resulting image, we obtain candidate objects to be arms of the user. By applying a labelling algorithm to obtain each object individually, a Principal Component Analysis is computed to each one to obtain its center and orientation. Using that information, we intercept the silhouette of the arm with a line obtaining the upper point of the interception which indicates the hand position. A Kalman filter is then applied to track the hand and based on state machines to describe gestures (Start, Stop, Pause) we perform gesture recognition. We tested the proposed approach in a real case scenario with different users and we obtained an accuracy around 89,7%.

  • 1953
  • 4363