Przemyslaw M. Szecówka

Simultaneous quantification of carbon monoxide and methane in humid air using a sensor array and an artificial neural network

Abstract The simultaneous quantification of carbon monoxide and methane in humid air is presented. The response of a three-sensor array, including an undoped and a platinum doped tin dioxide sensor showing non-ideal selectivity and a humidity sensor is fed into an optimised feed forward back propagation artificial neural network in order to obtain the carbon monoxide and methane concentration as network output. The gaseous environments under study were ternary mixtures in the concentration ranges of 0–0.5% methane, 0–1000 ppm carbon monoxide and 0–60% relative humidity at 20°C. The network structure, network output with respect to a priori known test concentrations and the influence of the size of the training data set is discussed.

APPLICATION OF SENSOR ARRAY AND NEURAL NETWORKS FOR QUANTIFICATION OF ORGANIC SOLVENT VAPOURS IN AIR

Abstract Organic solvents represent significant class of air pollutants. Mixtures of butanol and aromatic compounds are classified among the most commonly used there. The concept of two sensor systems capable of measurements and analysis of butanol/xylene and butanol/toluene mixtures is presented. Sensor array consists of four commercial, tin oxide based, semiconductor type gas sensors (TGS 800 series). For the sensors characterisation manually operated gas installation is constructed. Feedforward neural networks are developed for appropriate analysis of sensors responses. Both systems provide measurements of several single compounds concentrations with inaccuracy not exceeding 15% of range. Humidity influence on system responses is rejected. Possibility of portable realisation make the systems potential replacement of traditional gas analysing devices, especially in off-laboratory applications.

Humidity insensitive thick film methane sensor based on SnO2/Pt

Abstract The influence of environment humidity on electrical parameters is one of the basic disadvantages of the described SnO2 sensors. Due to complex research, the authors have managed to work out cermet composition (SnO2–Pt-black) which eliminates humidity influence on methane detection. In this paper, the basic characteristics of this latest methane sensor are presented.

Multipoint laser Doppler vibrometry using holographic optical elements and a CMOS digital camera

A laser Doppler vibrometer (LDV) is described in which holographic optical elements are used to provide the interferometer reference and object illumination beams. A complementary metal-oxide semiconductor camera, incorporating a digital signal processor, is used to carry out real-time signal processing of the interferometer output to allow multipoint LDV to be implemented.

On Hardware Implementation of Flexray Bus Guardian Module

FlexRay is a new standard of communication between electronic devices installed in a vehicle. The protocol is based on mechanisms known from telecommunication networks coupled with real time requirements. Paper describes a creative study of the new concept, consisting in implementation of selected mechanisms and devices in dedicated digital circuit. Bus guardian block, responsible for enabling/disabling the access to media and error detection was selected. The architecture, containing a series of finite state machines, watchdogs, and other logic, controlled by the programmable registers, accessible via the serial interface, was proposed. The design was implemented in VHDL and verified. The rough synthesis for a programmable circuit (FPGA) was successfully performed. FlexRay protocol is still in the development phase. The authors referred to the preliminary version of the specification.

Limitations of sensitivity analysis for neural networks in cases with dependent inputs

In this paper the limitations of the sensitivity analysis method for feedforward neural networks in the cases of dependent input variables are discussed. First, it is explained that in such cases there can be many functions implemented by neural networks that will accurately approximate training patterns. Then it is pointed out that many of these functions do not allow for proper estimation of the inputs importance using the sensitivity analysis method for neural networks. These two facts are demonstrated to be the reason why one can not completely rely upon the results of this method, when evaluating a real importance of inputs. Examples with graphs visualizing the discussed phenomena are presented. Finally, general conclusions about overall usefulness of the method are introduced.

Hardware approach to the artificial hand control algorithm realization

The concept of the bioprosthesis control system implementation in the dedicated hardware is presented. The complete control algorithm was analysed and the decomposition revealing the parts which could be calculated concurrently was made. Specialized digital circuits providing the wavelet transform and the neural network calculations were designed and successfully verified. The experiment results show that the proposed solution provides the desired dexterity and agility of the artificial hand.

Characterization of fatigued Al lines by means of SThM and XRD: Analysis using fast Fourier transform

Abstract Longitudinal performance and reliability of microelectronic structures is strongly influenced by the condition of interconnects. Degradation processes invoke changes, progressive in time, on the surface, in the body of interconnect layer, in the boundary between interconnect and the Si/SiO 2 substrate, and in the area of substrate near Al line. Geometrical scale of these changes may vary in wide range, reaching nanometers. The authors investigate the condition of Al path of a fatigued commercial electronic circuit (memory), using in-house developed scanning thermal microscope (SThM) and commercial high resolution X-ray diffractometer (XRD). Series of SThM images were obtained for varying temperature of Wollaston probe working in active mode. The images, after processing by 2-dimensional spatial FFT, reveal various ingredients of the surface and internal structure of the Al line. FFT power spectrum dispersion is proposed as a measure of the amount of information available from the scan image. This measure may be used to determine the most efficient temperature of Wollaston probe. The result is a preliminary analysis of feasibility of the SThM approach for characterization of degradation process. In general SThM shall be perceived as a new technique for reliability analysis.

Control of dexterous hand - algorithm implementation issues

This paper relates to the research on a dexterous hand prosthesis conducted at the Wroclaw University of Technology. The possibility of aiding the prosthesis control system by utilization of application specific digital circuits is presented. Several exemplary designs, prepared during some of to-date works conducted by authors, have been presented. Discussed solutions are part of a bigger project that is still ongoing and are still being developed.

FFT Based EMG Signals Analysis on FPGAs for Dexterous Hand Prosthesis Control

This paper relates to the research on a dexterous hand prosthesis conducted at the Wroclaw University of Technology. The possibility of recognizing human intention by digital processing of electromyographic (EMG) signals is presented. The realization of the decision-making logic in specialized digital circuits is investigated into. The article specifically deals with the issue of the Fast Fourier Transform (FFT) algorithm floating-point implementation.