João L. Monteiro

A networked platform for agricultural management systems

Greenhouse control computers are an essential part of modern greenhouse operation. Climate, irrigation and nutrient supply must be controlled, in an economical way, to produce the best crop conditions. Current research on CO 2 enrichment and optimal growth strategies implies the use of powerful tools, either based on hardware or software. This paper describes the design and implementation of a distributed data acquisition and control system for computerised agricultural management systems that is being developed at Universidade of Tras-os-Montes and Alto Douro, Vila Real. Different communications platform concepts, such as Controller Area Network (CAN), Wireless Technologies, Ethernet and Internet tools supported by Transfer Control Protocol/Internet Protocol (TCP/IP) and e-mail tools supported by Simple Mail Transfer Protocol (SMTP) were used to achieve a network with a low-cost, flexible, and functional characteristics. The system management and maintenance tasks are divided into two types of performance levels. At a lower supervision level, a Local Controller placed in the greenhouses performs the monitoring/control and communications actions. The management decisions are performed at the higher level. The techniques and tools, which provide to the user a transparent, friendly and intuitive Graphical User Interface (GUI) will be presented.

The application of reconfigurable logic to controller design

Abstract This paper presents a framework that performs the programmable logic synthesis of rule-based descriptions of concurrent controllers. These descriptions can be obtained from several specification models of those controllers (for example, Control Interpreted Petri net, Grafcet or the IEC 1131-3 Sequential Function Chart). The internal description, in the form of symbolic conditional decision rules, is then transformed into a format that is accepted by standard FPLD and FPGA simulators and synthesisers, for example OrCAD or VHDL. The concurrent state machine model of the logic controller is verified using the well-developed Petri-net theory, and then it is translated through automated processes into a selected FPGA specification format, for example the Xilinx netlist format (XNF). This paper presents part of a broad project in the field of hardware/software co-design. The main purpose is to develop different implementations of controllers using a simple, standard and well-known design methodology like SFC (Grafcet) or Petri nets. The paper deals exclusively with the design of FPGA-based controllers.

From interpreted Petri net specification to reprogrammable logic controller design

The goal of this paper is to present the design methodology for the modelling and synthesis of discrete event controllers for compact, fast and reliable embedded systems, using related Petri net theory, rule-based system theory (conditional mathematical logic), and hardware description languages (VHDL, Verilog). The well structured specification, which is represented in the human readable logic language, has a direct impact on the validation, formal verification and implementation of application specific logic controllers (ASLC) mapped into reconfigurable logic devices (FPGA). Reprogrammable logic controllers (RLC) may replace traditional PLCs in many industrial applications.

Study of vital sign monitoring with textile sensors in swimming pool environment

This paper presents the results of a series of experiments aiming at the optimisation of vital sign monitoring using textile electrodes to be used in a swimsuit. The swimsuit will integrate sensors for the measurement of several physiological and biomechanical signals; this paper will focus on ECG and respiratory movement analysis. The data obtained is mainly intended to provide tools for evaluation of high-performance swimmers, although applications can be derived for leisure sports and other situations. A comparison between electrodes based on different materials and structures, behaviour in dry and wet environments, as well as the behaviour in different extension states, will be presented. The influence of movement on the signal quality, both by the muscular electrical signals as well as by the displacement of the electrodes, will be discussed. The final objective is the integration of the electrodes in the swimsuit by knitting them directly in the suits fabric in a seamless knitting machine.

Path loss exponent analysis in Wireless Sensor Networks: Experimental evaluation

Wireless Sensor Networks are an emerging technology which has been recently adopted in many applications. Due to its wireless nature, the analysis of the radio propagation models plays an important role for performance evaluation in both theoretical and practical aspects. In this regards, path loss exponent is one of the most important parameter which has been considered widely in wireless communications analysis. There are several theoretical evaluations of path loss exponent for wireless sensor networks available in the literature. However there is a lack of experimental evaluation of both path loss exponent and the effect of shadowing. In this paper, three environments (free space, in building and industrial), where wireless sensor nodes are widely deployed, have been chosen in order to evaluate the experimental analysis. Path loss and path loss exponent are measured by means of Received Signal Strength Indicator (RSSI) and based on them, the standard deviation of shadowing effect is also calculated. All the measured parameters are compared with the theoretical analysis available in the literatures.

Yarn Evenness Parameters Evaluation: A New Approach

This paper presents MPS1 (Mass Parameterization System), an automatic system for determination of mass characteristics of textile yarn. It is based on 1 mm parallel capacitive sensors, working online or offline. This new approach allows direct measurement of yarn mass in the 1 mm range (increasing the resolution by eight times) [Pinto, J. G., Dissertação de Mestrado, Minho University, 2004; Baxter, L. Capacitive sensors: design and applications, IEEE Press, 1997]. Acquisition and data processing are performed in Labview™ from National Instruments. All parameters commonly used in the textile industry are determined for different values of sensitivity defined interactively by the operator. In MPS1, the new parameters were used (integral of deviation rate [IDR%], signal processing techniques based on the fast Walsh-Hadamard Transform and on fast impulse frequency determination [FDFI]) and others adapted (deviation rate [DR%], spectograms, frequency and mass variation diagrams, coefficient of variation [CV%], mean deviation [U%], faults counting and extension). Anew feature of this system is also the online automatic quality classification of mass parameters.

PLD implementation of logic controllers

This paper presents a unified design environment of concurrent logic controllers, based on the use of Petri nets, rule-based description languages and PL4 specification languages (especially AMD Palasm 4). The straightforward templates are presented that made possible a rule-based Petri net specification to be simulated and then efficiently synthesised with modern programmable devices. Though the example presented in this paper is relatively trivial, the concepts are directly applicable in the more realistic designs.

Multimodal fusion of the finger vein, fingerprint and the finger-knuckle-print using Kernel Fisher analysis

We proposed the fusion of the finger vein, fingerprint and the finger-knuckle-print.We used the fusion of these three biometric modalities in the feature level and also the decision level.The proposed approach contains three phases: enhancement, feature extraction and classification.We used the feature selection for enhance the feature fusion level by reducing the space and also enhancing the recognition performances. Unimodal biometric have improved the possibility to establish systems capable of identifying and managing the flow of individuals according to the available intrinsic characteristics that we have. However, a reliable recognition system requires multiple resources. This is the main objective of the multimodal systems that consists of using different resources. Although multimodality improves the accuracy of the systems, it occupies a large memory space and consumes more execution time considering the collected information from different resources. Therefore we have considered the feature selection, that is, the selection of the best attributes that enhances the accuracy and reduce the memory space as a solution. As a result, acceptable recognition performances with less forge and steal can be guaranteed. In this paper we propose an identification system using multimodal fusion of finger-knuckle-print, fingerprint and fingers venous network by adopting several techniques in different levels for multimodal fusion. A feature level fusion and decision level is proposed for the fusion of these three biological traits. An optimization method for this multimodal fusion system by enhancing the feature level fusion is introduced. The optimization consists of the space reduction by using different methods.

Cork Parquet Quality Control Vision System Based on Texture Segmentation and Fuzzy Grammar

This paper presents a quality control vision system developed for the inspection of cork parquets that is already applied in the Portuguese cork industry. It is devoted specifically to the most critical quality issues: visibility of the lowest layer (BASE) on the noble layer (UPPER) and the homogeneity of this noble layer. Since these aspects are related with the texture of the raw material, the system was based on texture segmentation techniques. Features used were extracted from detail images of the wavelet transform. The classifier consists of a fuzzy grammar inference system. The segmentation procedure revealed a good performance indicated by high classification rates. Behavior in the industrial environment has been demonstrating high performance, revealing good perspectives for full spread industrialization.

Using a multi-agent system approach for microaneurysm detection in fundus images

OBJECTIVE Microaneurysms represent the first sign of diabetic retinopathy, and their detection is fundamental for the prevention of vision impairment. Despite several research attempts to develop an automated system to detect microaneurysms in fundus images, none has shown the level of performance required for clinical practice. We propose a new approach, based on a multi-agent system model, for microaneurysm segmentation. METHODS AND MATERIALS A multi-agent based approach, preceded by a preprocessing phase to allow construction of the environment in which agents are situated and interact, is presented. The proposed method is applied to two available online datasets and results are compared to other previously described approaches. RESULTS Microaneurysm segmentation emerges from agent interaction. The final score of the proposed approach was 0.240 in the Retinopathy Online Challenge. CONCLUSIONS We achieved competitive results, primarily in detecting microaneurysms close to vessels, compared to more conventional algorithms. Despite these results not being optimum, they are encouraging and reveal that some improvements may be made.