Aerodynamic optimization via multi-objective micro-genetic algorithm with range adaptation,knowledge-based reinitialization,crowding and ε-dominance

In this study, an optimization of the airfoil of a sailplane is carried out by a recently developed multi-objective genetic algorithm based on microevolution, containing crowding, range adaptation, knowledge-based reinitialization and ε-dominance. Its efficiency was tested on a set of test problems. The results are encouraging, suggesting that very small populations can be used effectively to solve real-world multi-objective optimization problems in many cases of interest.     

Morphometric and some immunohistochemical characteristics of human choroids plexus stroma and psammoma bodies

Psammoma bodies (PBs) are one of many choroids plexus aging changes. The aim of our research was to perform the quantification of PBs' presence in human choroids plexus stroma, as well as to evaluate the characteristics of choroids plexus stroma in cases in which PBs were present. Afterwards, the observations of the histochemical analysis would be confirmed by immunohistochemical analysis. Choroid plexuses of 30 cadavers were used for the histochemical and, choroids plexuses of 15 cadavers in which PBs' presence was confirmed during the histochemical analysis, were used as material for the immunohistochemical analysis. Light microscopy, histochemical, immunohistochemical, and morphometric method were applied during the study. Classification of the cases was performed by cluster analysis. We observed increase of choroids plexus PBs' presence during the aging process. But this increase is not linear. Their presence is the largest in the second cluster that is younger than the third and older than the first. Nuclear morphometric parameters of the stroma in these cases showed that the cellular composition in this cluster is different than in other two and, that contain larger number of lymphoid cells. Immunohistochemical analysis showed PBs' positive reaction on vimentin, CD45R0, and LCA markers, while in their vicinity, as well as inside them, numerous T-cells were observed. So, the presence of CD45R0 and LCA-positive T cells, PBs' positive reaction on the same markers, indirectly connect these cells with PBs' formation process.     

Modelling of V–Hz and vector controlled ASDs in PSCAD/EMTDC for voltage sag studies

This paper deals with modelling and performance of adjustable speed drives (ASDs) subjected to voltage disturbances in electric supply. The aim of this study was to develop appropriate models of typical ASD and investigate their sensitivity to voltage disturbances under various practical modes of operation and control. Accordingly, scalar controlled open and closed loop volts–hertz (V–Hz) and vector controlled closed loop ASDs are modelled in PSCAD/EMTDC environment, and their performance in the presence of voltage disturbances is investigated under typical operating and loading conditions.     

Nonstationary harmonic modeling for ECG removal in surface EMG signals

We present a compact approach for mitigating the presence of electrocardiograms (ECG) in surface electromyographic (EMG) signals by means of time-variant harmonic modeling of the cardiac artifact. Heart rate and QRS complex variability, which often account for amplitude and frequency time variations of the ECG, are simultaneously captured by a set of third-order constant-coefficient polynomials modulating a stationary harmonic basis in the analysis window. Such a characterization allows us to significantly suppress ECG from the mixture by preserving most of the EMG signal content at low frequencies (less than 20?Hz). Moreover, the resulting model is linear in parameters and the least-squares solution to the corresponding linear system of equations efficiently provides model parameter estimates. The comparative results suggest that the proposed method outperforms two reference methods in terms of the EMG preservation at low frequencies.     

Explicit form of new class of extremal filter functions with mini-max behaviour of summed sensitivity function

In this article, the all-pole low-pass filter function with mini-max for the summed sensitivity function in the pass-band is considered. With the application of Chebyshev polynomials of the first kind, the proposed filter function is obtained in an explicit form with a maximum number of oscillations of the summed sensitivity function in the pass-band. The calculation of the filter function is derived by using the summed sensitivity function as a starting point. New original approximation function is derived in order to achieve a mini-max summed sensitivity function in the filter pass-band. Sensitivity analysis is carried out and a comparison of the summed sensitivity and the group delay of the proposed and classical all-pole filters is given. Minimisation of the summed sensitivity function is important for reduction of the deviation of the magnitude response caused by temperature changes of the continuous-time active filters implemented into the analogue front end or as programmable chips.     

A multimodal hand-based verification system with an aliveness-detection module

This paper presents a multimodal biometrie verification system based on the following hand features: palmprint, four digitprints and four fingerprints. The features are obtained using the Karhunen-Loève transform based approach, and information fusion at the matching-score level was applied. We experimented with different resolutions of the regions of interest, different numbers of features and several normalization and fusion techniques at the matching-score level. To increase the reliability of the system to spoof attacks we included an aliveness-detection module based on thermal images of the hand dor sa. The verification performance when using a system configuration with optimum parameters, i.e., resolution, number of features, normalization and fusion technique, showed an equal error rate (EER) of 0.0020%, which makes the system appropriate for the implementation of high-security biometric systems.     

Computer-controlled mechanical simulation of the artificially ventilated human respiratory system

A mechanical lung simulator can be used to simulate specific lung pathologies, to test lung-function equipment, and in instruction. A new approach to mechanical simulation of lung behavior is introduced that uses a computer-controlled active mechatronic system. The main advantage of this approach is that the static and dynamic properties of the simulator can easily be adjusted via the control software. A nonlinear single-compartment mathematical model of the artificially ventilated respiratory system has been derived and incorporated into the simulator control system. This model can capture both the static and dynamic compliance of the respiratory system as well as nonlinear flow-resistance properties. Parameters in this model can be estimated by using data from artificially ventilated patients. It is shown that the simulation model fits patient data well. This mathematical model of the respiratory system was then matched to a model of the available physical equipment (the simulator, actuators, and the interface electronics) in order to obtain the desired lung behavior. A significant time delay in the piston motion control loop has been identified, which can potentially cause oscillations or even instability for high compliance values. Therefore, a feedback controller based on the Smith-predictor scheme was developed to control the piston motion. The control system, implemented on a personal computer, also includes a user-friendly interface to allow easy parameter setting.     

A novel structure of the fully differential CMOS amplifier with symmetric active load

In this article, we propose a novel general structure of a linear symmetric fully differential voltage amplifier with a symmetric output. It is applicable to all sets of complementary component pairs such as BJT, JFET and MOSFET. We demonstrate the superiority of the proposed circuit in comparison with the state-of-the-art solutions. The characteristics are illustrated in both frequency and time domains, and a comparison is given between the proposed amplifier and the traditional differential amplifier with a current mirror as an active load for the same set of complementary components in CMOS equally sized W/L = 150/3 technology. The static voltage transfer characteristic of the proposed amplifier has an extremely small linearity error. The deviation from the linear characteristics is less than 0.018 mV for the amplitude of the output differential voltage of 1 Vpp. The common-mode gain by symmetric output is negligible because the proposed structure is fully symmetric. The simulation results demonstrate the efficiency of the proposed amplifier.     

Phase-synchroniser based on gm-C all-pass filter chain with sliding mode control

Phase-synchronisers have many applications in VLSI circuit designs. They are used in CMOS RF circuits including phase (de)modulators, phase recovery circuits, multiphase synthesis, etc. In this article, a phase-synchroniser based on g_m-C all-pass filter chain with sliding mode control is presented. The filter chain provides good controllable delay characteristics over the full range of phase and frequency regulation, without deterioration of input signal amplitude and waveform, while the sliding mode control enables us to achieve fast and predetermined finite locking time. IHP 0.25 µm SiGe BiCMOS technology has been used in design and verification processes. The circuit operates in the frequency range from 33 MHz up to 150 MHz. Simulation results indicate that it is possible to achieve very fast synchronisation time period, which is approximately four time intervals of the input signal during normal operation, and 20 time intervals during power-on.