2001
Authors
Valente, A; Couto, C; Correia, JH;
Publication
TRANSDUCERS '01: EUROSENSORS XV, DIGEST OF TECHNICAL PAPERS, VOLS 1 AND 2
Abstract
This paper reports the design, modelling, fabrication and assembly of a silicon bulk-micromachined soil moisture microsensor using the Dual-Probe Heat-Pulse (DPHP) method. Soil humidity measurement is essential to study soil preservation and control the development of plants, namely in closed ecosystem. The DPHP method uses a heater (Peltier effect) and a temperature probe (Seebeck effect) to determine the volumetric heat capacity of the soil and hence water content (theta (v)). This is the first time that the DPHP method is implemented in a microdevice and the first integrated sensor for soil moisture. This microdevice is more suited to measure at different soil depths in a non-destructive and automated manner.
2001
Authors
Brito, L; Neves, J; Moura, F;
Publication
E-BUSINESS AND VIRTUAL ENTERPRISES: MANAGING BUSINESS-TO-BUSINESS COOPERATION
Abstract
Emerging technologies that allow a two-way communication between companies, or among companies and their customers, are changing the rules of the market, facilitating the emergence of virtual entities that have to be supported by some kind of platform. Making it is the main objective of this work, materialized in a Mobile Agent Architecture (MAA) which supports the emerging world of the m-Commerce (mobile-Commerce): the MAgnUM architecture, The MAA's development was based on the principles of process and knowledge abstraction, compositionality, reuse, formal semantics, formal evaluation, and security.
2001
Authors
Machado Ferreira, CM; Dias Pinto, JA; MacIel Barbosa, FP;
Publication
2001 IEEE Porto Power Tech Proceedings
Abstract
In this paper a combined Monte Carlo-Hybrid Transient Stability approach for the dynamic security analysis of a multimachine power system is proposed. This approach evaluates a probabilistic measure of the transient stability, instead of just a particular response to a specified disturbance. Due to the large number of simulations required, the application of a hybrid method to assess transient stability reduces drastically the computing time. A probabilistic version of the software package TRANsySTEM, developed by the authors to study the transient security of a multimachine system, was applied to a test power network. During the simulation time, the occurrence of disturbances and the subsequent protective actions are assumed as a stochastic process. Finally, the obtained results are discussed and some conclusions that provide a valuable contribution to the understanding of the system dynamics are pointed out. © 2001 IEEE.
2001
Authors
Villavicencio, G; Oliveira, JN;
Publication
Reverse Engineering - Working Conference Proceedings
Abstract
This paper sketches a discipline for reverse engineering which combines formal and semi-formal methods. Among the former is the algebra of programming, which we apply in "reverse order" so as to reconstruct formal specifications of legacy code. The latter includes code slicing, used as a means of trimming down the complexity of handling the formal semantics of all program variables at the same time. A strong point of the approach is its constructive style. Reverse calculations go as far as imploding auxiliary variables, introducing mutual recursion (if applicable) and transforming semantic functions into standard generic programming schemata such as cata/paramorphisms. We illustrate the approach by reversing a piece of code (from C to HASKELL) already studied in the codeslicing literature: the word-count (wc) program.
2001
Authors
Castro, LF; Costa, VS;
Publication
Logic Programming, 17th International Conference, ICLP 2001, Paphos, Cyprus, November 26 - December 1, 2001, Proceedings
Abstract
2001
Authors
Mendonca, HS; Silva, JM; Matos, JS;
Publication
IMTC/2001: PROCEEDINGS OF THE 18TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS 1-3: REDISCOVERING MEASUREMENT IN THE AGE OF INFORMATICS
Abstract
In this paper an alternative technique for differential gain and phase testing of video ADCs based on the use of joint time-frequency analysis is presented. This technique can lead to a significant improvement in ADC testing time and in the amount of information provided by these specific tests.
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