The automatic construction of a hierarchical classifier is described. The construction process uses the same classifier to select the features, which is used later for the classification itself. The construction leads to a binary decision tree. Every node is labelled with a feature vector. The classical statistical approach to feature selection is presented. The add-on algorithm provides feature vectors of minimal length without regarding the classifier. Two applications are described and the results, reached by the classical statistical algorithm and the new hierarchical classifier, are...
This paper suggests a new approach to checking understood as a validation and diagnostic procedure of the analogue measurement channels in 4-20mA standard. The discussed method is very useful in field conditions especially for widespread long distance systems like those on ships. In each case it supports traditional methods but in the same specific situations of temperature measurement it can indicate a faulty channel.
Due to the complexity of processing, the total error of the analog to digital conversion being the difference between the input and output signal is set of several constituent errors. They include, among others, integral nonlinearity error and differential nonlinearity error. Different methods of defining the errors depending on their source of origin as well as certain ambiguity of the presentation manner regarding information on converter parameters between manufacturers makes a clear-cut assessment of the total error of analog - digital processing trajectory difficult. This paper is an...
A Radial Basis Function Network (RBFN) classifier for hard fault location in CMOS analogue circuit is presented. The network is trained by means of a fault dictionary containing the faulty circuit response, which is obtained by simulating the supply current dynamic response.
Frequency Response Analysers (FRA) are commonly employed to monitor the corrosion state of metallic antiquities. Commercial devices, though very accurate and versatile, are often rather costly and require a long time to complete the Electrochemical Impedance Spectroscopy (EIS). This paper describes a low cost and portable alternative to commercial FRAs that also embeds the potentiostatic function and therefore can be used in the field without requiring external devices. The proposed instrument is based on a compact DSP board and employs a sine-fit algorithm for the impedance measurement; the...
Analog clusters embedded within a larger design which is equipped with IEEE Std 1149.4 mixed-signal test bus are usually non-scan user-defined circuits. Diagnosis of them by means the test bus is a significant challenge. Virtual probes created by analog modules of the bus impact on the results of measurement but it can be avoided by properly strategy of diagnosis. Possibilities of diagnosis by means of the bus are increased by different modes of the bus operation. They are particularly useful for diagnosis of extended clusters. Test features of the bus can appear non-sufficient in the...
A technique for the systematic design of fault-tolerant automatic measurement systems was proposed by the authors in a previous paper. It is based on the use of ”analytical redundancy” relationships concerning both the measurement system and the monitored devices. In this paper, the technique was applied to the handling of sensors and actuators used for the electronic control of internal combustion engines. This represents the preliminary step toward the realisation of a fault tolerant measurement and control system for the automotive systems. The paper describes in detail the realised...
Recently, a standardised software interface for measuring instruments has been proposed by the IVI (Interchangeable Virtual Instruments) Foundation. The aim of the proposal is to provide independence of measuring system software from the specific instrumentation employed in a particular implementation of a test system, allowing for total interchangeability of instruments within a given class. Replacement or upgrades of hardware within an automatic test system would then be possible without affecting measurement software. The authors have implemented IVI-like drivers for some instrument...
The paper deals with the transformation of term quality according ISO standards into industrial practice. There are given investigations which give background for understanding of noise structure generated by a belt conveyor. It is shown that the role of idlers to generated noise by the belt conveyor is crucial. It has shone that for quality assessment of idlers, parameters connected with vibration has to be taken. The paper gives: general consideration on the quality term, describes dynamic properties of idler/(test rig), idler/(belt conveyor belt structure), presents results of computer...
Signals of quasistationary nature are often met in diagnostics and NDT systems. In the paper model for quasistationary signals with periodically varying deviation is proposed. Procedures for wide band quasistationary signal envelope detection are analyzed and tested using both simulated signals and records of Barkhausen noise. Accuracy and speed of detection of these procedures are estimated using digital signal processing techniques.