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Publications

2006

Relational sampling for data quality auditing and decision support

Authors
Cortes, B; Oliveira, JN;

Publication
Enterprise Information Systems VI

Abstract
This paper presents a strategy for applying sampling techniques to relational databases, in the context of data quality auditing or decision support processes. Fuzzy cluster sampling is used to survey sets of records for correctness of business rules. Relational algebra estimators are presented as a data quality-auditing tool.

2006

Concept study of an implantable microsystem for electrical resistance and temperature measurements in dairy cows, suitable for estrus detection

Authors
Morais, R; Valente, A; Almeida, JC; Silva, AM; Soares, S; Reis, MJCS; Valentim, R; Azevedo, J;

Publication
SENSORS AND ACTUATORS A-PHYSICAL

Abstract
In cattle breeding industry, where artificial insemination techniques are employed, the successful detection of estrus onset leads to considerable cost-saving in herd management. One of the most reliable approaches is based on the determination of progesterone concentration in milk. However, these methods rely on the biosensor concept where a biological substrate is used in a chemical-binding reaction to directly or indirectly produce some effect (electrical or light) that is used at the transducer level. These methods present several drawbacks concerning real-time measurements due to the complexity of the reactions involved and reagent/waste handling. Another approach is to combine measurements of temperature and electrical resistance of reproductive tissues to predict estrus. Using a low-power microsystem with wireless capabilities it is possible to take these measurements in situ and more frequently. The proposed microsystem comprises a second-order delta-sigma modulator for analog-to-digital conversion and a class-E radio-frequency (RF) transmitter operating in the ISM-band of 433 MHz to transfer acquired data to a collar. Electrical resistance is measured by using a modified Wenner array and temperature by the on-chip temperature sensor. System (including battery and antenna) package is made of a tissue-compatible material to allow implantation in the cow's vulvar muscle. Since estrus prediction is based on relative changes of the two correlated parameters, calibration is not necessary. Some preliminary results regarding the measuring concept are presented.

2006

Fractional PDa control of an hexapod robot

Authors
Silva, MF; MacHado, JAT;

Publication
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
This paper studies the performance of a Fractional Order PD a controller in a hexapod robot with three dof legs and leg joint actuators having saturation. For that objective the robot prescribed motion is characterized in terms of several locomotion variables. Moreover, two indices measure the walking performance based on the mean absolute density of energy per travelled distance and on the hip trajectory errors. A set of simulation experiments reveals the influence of the different controller tuning upon the proposed indices. Copyright © 2006 IFAC.

2006

Topographic segmentation and transit time estimation for endoscopic capsule exams

Authors
Coimbra, M; Campos, P; Cunha, JPS;

Publication
2006 IEEE International Conference on Acoustics, Speech and Signal Processing, Vols 1-13

Abstract
The endoscopic capsule is a recent medical technology with important clinical benefits but suffering from a practical handicap: long exam annotation times. This paper shows how support vector machines can be used to segment the gastrointestinal tract into its four major topographic areas, allowing the automatic estimation of the clinically relevant gastric and intestinal transit times. According to medical specialists, this can reduce exam annotation times by up to 12%.

2006

Multi-functional probe for small-scale simultaneous measurements of soil thermal properties, water content, and electrical conductivity

Authors
Valente, A; Morais, R; Tuli, A; Hopmans, JW; Kluitenberg, GJ;

Publication
SENSORS AND ACTUATORS A-PHYSICAL

Abstract
In studies of vadose zone flow and transport processes, there is a need for a multi-functional probe for small-scale measurements of different soil properties measured within identical soil volumes. The proposed multi-functional probe was designed for simultaneous measurement of temperature, volumetric water content, water flow, and salinity in small-scale soil volumes. The probe, without the heater element, will be a 21.4 mm diameter by 50 mm long cylinder. The proposed system includes signal processing circuits, a microcontroller, and a RF transceiver with ZigBee (TM) protocol. Heat-pulse simulations results showed a reasonably good agreement between measured and fitted data with small deviations at the tail of temperature response curves. In addition, results indicate that the Wenner array configuration provides an excellent tool for EC measurements in soil. In conclusion, results also show that it is possible to implement the multi-functional in a small-scale microsystem.

2006

GRAPP 2006 - Proceedings of the 1st International Conference on Computer Graphics Theory and Applications: Foreword

Authors
Braz, J; Dias, M; Marcos, A; Jorge, J;

Publication
GRAPP 2006 - Proceedings of the 1st International Conference on Computer Graphics Theory and Applications

Abstract

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