Octávio Páscoa Dias

Brief paper: Hand movement recognition based on biosignal analysis

This paper proposes a methodology that analyses and classifies the electromyographic (EMG) signals using neural networks to control multifunction prostheses. The control of these prostheses can be made using myoelectric signals taken from surface electrodes. Finger motions discrimination is the key problem in this study. Thus the emphasis, in the proposed work, is put on myoelectric signal processing approaches. The EMG signals classification system was established using the linear neural network. The experimental results show a promising performance in classification of motions based on biosignal patterns.

Metrics and Criteria for Quality Assessment of Testable Hw/Sw Systems Architectures

The purpose of this paper is to present a novel methodology for assessing the quality of architecture solutions of hw/sw systems, with particular emphasis on testability. Criteria and metrics for quality assessment are proposed and used to assist the design team in selecting a ‘best-fitted’ architecture that satisfies not only functional requirements, but also test requirements. The methodology makes use of object-oriented modeling techniques. Near-optimum clustering of methods and attributes into objects is carried out, in such a way that objects with moderate complexity, low coupling and high functional autonomy, result. The main features of the methodology are ascertained through a case study.

Dataflow model property verification using Petri net translation techniques

Dataflow process networks lead to different theoretical model approaches and have demonstrated their adequacy in data-dominated intensive systems, namely Synchronous Dataflows. Since their appearance, dataflow models became too focused and specialized in their target applications. The paper presents a set of translating mechanisms allowing the mapping from dataflow models into Petri nets. This mapping allows taking advantage of Petri nets well-known properties verification capabilities and enriching dataflow models concerning scheduler information and resource allocation. This allows one to find out some hidden embedded features (model semantics and syntax) not normally addressed in dataflow analysis tools, which is briefly characterized. Dataflow model translation into Petri net domain give support to attain the required resource allocation under dataflow static scheduling list. This scheme allows one to make conclusion in Petri net domain to be applied in dataflow models to foresee the necessary amount of storage resources for each arc. An application example is used to illustrate the concept and effectiveness of the outlined approach.

Petri net verification techniques on Synchronous Dataflow models

Dataflow process networks lead to different theoretical model approaches and have demonstrated their adequacy in data-dominated intensive systems, namely Synchronous Dataflow. The paper presents a set of translating mechanisms allowing the mapping from dataflow models (Synchrounous Dataflows) into Petri nets. Study on invariants focused on misbehaving dataflow, in which there is no static scheduling are delved to find out more hidden embedded features not normally addressed in dataflow analysis tools. This scheme allows one to make conclusion in Petri net domain to be applied in dataflow models to foresee the necessary amount of storage resources for each are, as well as to unveil the effective maximum number of tokens and the potential maximum number of tokens for each Synchronous Dataflow. Dataflow model translation into Petri net domain will give support to attain the required resource allocation under a reduced (minor) dataflow where a static scheduling list still exists. An application example will be used to illustrate the concept and effectiveness of the outlined approach. Our focus in this paper is centered in the description, model validation and at property verification in Petri net domain, namely Invariant and reachability analysis.

On identifying and evaluating object architectures for real-time applications

Abstract This paper presents a methodology and tool support for the development of distributed real-time object-oriented systems, focusing on industrial automation applications. At system level, two different kinds of classes/objects are recognized: (i) application domain objects, which map directly to concepts and components of the problem domain, and (ii) design objects that are related to the functional requirements that the system have to meet. The approach provides a method for automatic identification of possible design objects architectures. A set of quality and testability metrics is proposed to evaluate the generated architectures, allowing the identification of the ‘best-fitted’ one.

Analysing storage resources on Synchronous Dataflows using Petri net verification techniques

Dataflow process networks have proved and demonstrated their adequacy in data-dominated systems, namely Synchronous Dataflows. Due to a multitude of domains, in where each realizes a model of computation, many different theoretical dataflow model approaches emerged. This paper presents a set of translating mechanisms allowing the mapping from Synchrounous Dataflows into Petri nets. Study on invariants focused on synchronous dataflows is presented, allowing one to make conclusion in Petri net domain to be applied in dataflow models to foresee the necessary amount of storage resources for each arc, as well as to expose the effective maximum number of tokens and the potential maximum number of tokens for each Synchronous Dataflow. This translation allows also, one to take benefit of the well known property verification capabilities of Petri, as well as, attain conclusions about the flow of data that are not possible using the Synchronous Dataflows, or that use dynamic programming to compute a schedule that minimizes the amount of data memory required from among the schedules, where the amount of storage resource for each arc is still unpredictable. An application example based on multistage implementation of a sample rate system will be used to illustrate the concept and effectiveness of the proposed approach. Our focus in this paper is addressed to the description of the translating mechanisms, model validation and at property verification in Petri net domain, namely invariant and reachability analysis.

A strategy to improve engineering teaching process based on an e-learning approach

This work presents a project which was realized with the objective of implementing an alternative solution to teaching methods. This solution involves the assistance of computers working as pedagogical tools complementary to the traditional methods that are used in the teaching of subjects such as Mathematics, Electrics and Electronics. Besides the background that has motivated the realization of this project, This work presents not only the strategies, principles and philosophy which were defined for the courses content but also the way in which a solution was implemented, as well as the strategy expected to be carried out to test the solution and evaluate the results of these tests. In addition, it also explores the alterations that this type of strategy may cause in the roles traditionally attributed to teachers and students, and the effect that these changes bring about in the teacher-student relationship. Finally, this paper also contains a brief presentation of the organizational structure of the solution, the phases and main tasks that this project involved, other phases expected to be carried out in the future, as well as its conclusions.

Automation and Real-Time Control of a Wine Bottling Production Line: An Object Oriented Based Hardware/Software Co-Design Case Study

Abstract The purpose of this work is to present a hw/sw electronic system, Fill, responsible for the automation and real-time control of a wine bottling production line. Fill is a sub-system of the IntelCaves (Intelligent Caves) system. An Object Oriented based methodology is used for system development. A key novelty of the implementation approach is the use of the bottle, as an active object, for synchronizing the production line. A prototype of Fill has been running without problems during the last 6 months. The system will be extended to other production lines and Companies.

Automatic optical inspection for detecting defective solders on printed circuit boards

Automated systems based on optical inspection are widely used in the production of electronic systems, mainly on the printed circuit board level. Detection of defects in the early stages of production, reduce costs by lowering the number of scraps and elevate overall quality standards. One of the main areas where defects arise, are in the solders of the components on printed circuit boards. This paper studies an implementation of an automated optical inspection system for detection of defective solder in through-hole components. The solution implemented in this system, relies on the correct thresholding of the acquired image and afterwards particle analysis on a rule-based approach, instead of using techniques such as template matching to compare the solders to a known template. The proposed solution reduces the overall processing time and makes for a more flexible solution. The experimental results show the efficiency of the proposed approach with a high rate of success using a minimum cycle time.

Test resource partitioning: a design and test issue

Product development economics and specs drive the need for on chip embedded test functionality. However, optimal partitioning of test functionality between a tester and a SOC is a non-trivial task, which must be solved during the system analysis phase. Hence, at system level, a trade-off analysis must be performed, in order to evaluate the costs and benefits of different partitioning schemes. The purpose of this contribution is to present a methodology and tools, using the Object Oriented (OO) Paradigm and UML, and a set of architectural Quality Metrics (QMs), to analyze the impact of different TRP schemes on systems architecture. A 4-core SOC case study is presented to guide the discussion.