Bravo C.,University of Los Andes, Venezuela |
Castro J.A.,University of Los Andes, Venezuela |
Saputelli L.,Hess Corporation |
Rios A.,University of Los Andes, Venezuela |
And 2 more authors.
Journal of Natural Gas Science and Engineering | Year: 2011
The oil production process is highly complex and requires the combination of several disciplines and technological tools for its management. System integration and the automation of the workflows required to develop oil production operations are two main problems nowadays at the oil and gas production industry. This work approaches these problems through the implementation of distributed artificial intelligence architecture, designed for the automated production management. The architecture comprises a standardized schema to access information sources, a production ontological framework and an intelligent workflow mechanism based on multi-agent systems and electronic institution. Our architecture present several novelties: the incorporation of the semantic integration, the extension of the agents theory through the electronic institutions paradigm to solve the real-time decision problems typical in the industry, the Holon-Agent hybrid model used to make more feasible its implementation, among others. An oil production management case study is presented in order to demonstrate the applicability of the proposed architecture. © 2011 Elsevier B.V.
Blanco-Delgado N.,Aerospace Research and Technology Center
GIM International | Year: 2011
The use of high-precision GPS for surveying applications has increased dramatically over the last decade. GPS receivers can provide high accuracy and rapid results, saving enormous amounts of time by covering large areas in a short time. While there have been some developments that have produced high-accuracy, real-time solutions with single-frequency receivers, the appearance of new signals and constellations is now making it possible to use two frequencies less expensively. Scientists have long discussed the potential of new signals for multi-frequency, multi-GNSS applications and have expressed a great interest in signal combinations, particularly those of carrier-phase measurements, involving multiple frequencies simultaneously. The use of triple-frequency combinations has, for example, been demonstrated to be of great interest for ambiguity resolution in precise carrier-phase-based positioning, for receiver autonomous integrity monitoring, and for ionospheric research. With 27 satellites in orbit and 23 operational satellites, GLONASS provides almost global coverage.
Hedjazi L.,Roche Holding AG |
Hedjazi L.,National Polytechnic Institute of Toulouse |
Aguilar-Martin J.,Aerospace Research and Technology Center |
Le Lann M.-V.,Roche Holding AG |
Le Lann M.-V.,National Polytechnic Institute of Toulouse
Pattern Recognition Letters | Year: 2011
In this paper we propose a feature selection method for symbolic interval data based on similarity margin. In this method, classes are parameterized by an interval prototype based on an appropriate learning process. A similarity measure is defined in order to estimate the similarity between the interval feature value and each class prototype. Then, a similarity margin concept has been introduced. The heuristic search is avoided by optimizing an objective function to evaluate the importance (weight) of each interval feature in a similarity margin framework. The experimental results show that the proposed method selects meaningful features for interval data. In particular, the method we propose yields a significant improvement on classification task of three real-world datasets. © 2010 Elsevier B.V. All rights reserved.
Martin-Escalona I.,Polytechnic University of Catalonia |
Barcelo-Arroyo F.,Polytechnic University of Catalonia |
Ciurana M.,Aerospace Research and Technology Center
2010 International Congress on Ultra Modern Telecommunications and Control Systems and Workshops, ICUMT 2010 | Year: 2010
Ad hoc networks are becoming increasingly relevant in positioning solutions, mainly due to the capabilities of current portable devices and the collaborative nature of such networks, which can improve some of the limitations of the positioning solutions in regular wireless networks. Scalability and accuracy are the most constraining factors of a location algorithm for ad hoc networks. This paper presents an algorithm for passive location in ad hoc networks. This algorithm uses the location traffic in the network to compute the position of the nodes. This passive behavior makes this solution ideal for scalability because one single active node can locate as many nodes as it can cover in the network. This paper provides a definition for the algorithm and explores the expected accuracy of passive positions. ©2010 IEEE.
Gutierrez E.,Aerospace Research and Technology Center |
Lopez-Salcedo J.A.,Autonomous University of Barcelona |
Seco-Granados G.,Autonomous University of Barcelona
2011 8th International Workshop on Multi-Carrier Systems and Solutions, MC-SS 2011 | Year: 2011
The design of efficient architectures for Multi-Carrier (MC) communication systems can be a challenging task when it involves the adoption of Filter-Bank Multi-Carrier (FBMC) modulation techniques. The main design issues found in FBMC systems are generated by the incorporation of band-limited shaping pulses. Yet, these pulses have many advantages in terms of performance, such as providing either improved spectral confinement or no frequency overlap between adjacent subcarriers. They also benefit from robustness in front of narrowband interferences, and reduced out-of-band power emission, among others. However, the advantages of FBMC schemes are often obscured when it comes to the implementation point of view. This is particularly true for the flexible FBMC systems, where on top of incorporating band-limited shaping pulses, no restrictions are imposed on the signal parameters (i.e. symbol rate, carrier spacing or sampling frequency). In this context, the present paper will provide a unified framework to describe flexible FBMC signals when both signal design and implementation criteria are combined. © 2011 IEEE.