Wyniki wyszukiwania - BazTech

1

Frequency response based curve fitting approximation of fractional-order PID controllers

Bingi Kishore, Ibrahim Rosdiazli, Karsiti Mohd Noh, Hassam Sabo Miya, Harindran Vivekananda Rajah

International Journal of Applied Mathematics and Computer Science

|

2019

|

Vol. 29, no. 2

311--326

EN

Fractional-order PID (FOPID) controllers have been used extensively in many control applications to achieve robust control performance. To implement these controllers, curve fitting approximation techniques are widely employed to obtain integer-order approximation of FOPID. The most popular and widely used approximation techniques include the Oustaloup, Matsuda and Cheraff approaches. However, these methods are unable to achieve the best approximation due to the limitation in the desired frequency range. Thus, this paper proposes a simple curve fitting based integer-order approximation method for a fractional-order integrator/differentiator using frequency response. The advantage of this technique is that it is simple and can fit the entire desired frequency range. Simulation results in the frequency domain show that the proposed approach produces better parameter approximation for the desired frequency range compared with the Oustaloup, refined Oustaloup and Matsuda techniques. Furthermore, time domain and stability analyses also validate the frequency domain results.

2

A new approach for the classification of event related potentials for valid and paradox reasoning

Papaodysseus C., Zannos S., Giannopoulos F., Arabadjis D., Rousopoulos P., Stachtea X., Papageorgiou C.

Biocybernetics and Biomedical Engineering

|

2016

|

Vol. 36, no. 1

292--301

EN

In the present paper, a novel approach is introduced for comparing and classifying recorded ERP signals from subjects applying valid (Aristotle's) and paradox (Zeno's) syllogisms. In fact, the authors conceived and realized a corresponding experiment, as well as a new method for processing, fitting and classifying the corresponding captured ERP signals into groups according to their similarity. Subsequently, for each such group, an ideal curve that represents all signals of the group has been evaluated for valid and paradox reasoning separately. These ‘‘ideal representatives’’ manifest essential statistical differences per subject for a considerable number of electrodes (5 electrodes with 99% level of confidence, 14 electrodes with 95% level of confidence, 17 electrodes with 90% level of confidence). These results support the assumption that the obtained ideal representatives may indeed reflect essential differences in the underlying brain functions which generated the obtained ERPs. Equivalently, one may claim that the performed experiment and the associated results manifest statistically essential differences between the mental functions during valid and paradox reasoning.

3

Analysis of cells elasticity based on force-distance curves obtained from atomic force microscopy

Płaczek B.

Journal of Medical Informatics & Technologies

|

2015

|

Vol. 24

173--179

EN

Automated techniques for measuring elasticity parameters of cells enable development of new diagnosis methods. An important elasticity parameter is the Young’s modulus (YM), which has been effectively used to characterize different cell properties, e. g., platelet activation, locomotion, differentiation, and aging. This paper deals with the problem of automated determination of cells YM based on the force-distance curves obtained from atomic force microscope. During experiments, the YM of cells was determined by using contact point detection and curve fitting algorithms. Experimental results were compared for two theoretical models of indentation: Hertz model, and Sneddon model. The results show that single indentation model allows a satisfactory accuracy to be obtained only for a subset of the force-distance curves. The most appropriate model for a given curve can be selected based on the fitting error analysis.

4

Hyper-elastic modelling of intervertebral disc polyurethane implant

Pawlikowski M., Skalski K., Sowiński T.

Acta of Bioengineering and Biomechanics

|

2013

|

Vol. 15, no. 2

43--50

EN

Artificial materials including various kinds of polymers like polyurethanes are more and more widely used in different branches of science and also in biomedical engineering. The paper presents the process of creating a constitutive equation for a polyurethane nanocomposite which is considered to be hyper-elastic. The constitutive modelling was conducted within the range of application of the material as one of the components of lumbar intervertebral disc prosthesis. In the paper, the biomechanics of the lumbar spine and the most frequently applied intervertebral disc prostheses are described. Also a polyurethane nanocomposite as a new material to be applied in prostheses is presented. The way of formulating a constitutive equation by means of mathematical formulae is described. Four various hyper-elastic potential functions are considered, i.e., Ogden, Neo-Hookean, Yeoh and Mooney–Rivlin. On the basis of monotonic compression tests the best hyper-elastic model for the material considered was chosen and hyper-elastic constants were calibrated. Finally, the constitutive model was validated on the basis of FE analysis. The paper ends with a conclusion and presentation of further plans of research directed towards the development of a constitutive equation and its application in computer simulations by means of the finite element method.

5

A new approximation method for the trend hypersurface analysis for elevation of drilhole data

Karakus D., Safak S., Onur A. H.

Archives of Mining Sciences

|

2011

|

Vol. 56, no 1

47-58

EN

This paper presents a new mathematical approach to a well known interpolation technique of the trend surface analysis method that allows for fast and accurate estimation of the spatial distribution of mineral resources. The most popular and accurate method for estimating the quality of an ore body spatial distribution uses geostatistics built upon complex variogram modeling. To simplify this application and maintain sensitivity, a trend hypersurface analysis method was reformulated, and a novel computer algorithm was established to analyze data collected from a limestone quarry in Turkey. However 4 dimensional variables obtained from drill hole data and data type limit the surface analysis studies. This study compares the measured CaCO3 contents obtained from 31 drill holes with data derived from mathematical modeling.

PL

Praca opisuje nowe podejście matematyczne do znanej techniki interpolacji stosowanej w analizie powierzchni trendu, umożliwiające szybką i dokładną estymację rozkładu przestrzennego złoża surowców mineralnych. Najbardziej znaną i najdokładniejszą metodą estymowania jakości rozkładu przestrzennego złoża rudy wykorzystuje metody geostatystyki zbudowane w oparciu o modelowanie z użyciem złożonych wariogramów. Aby uprościć tę aplikację jednocześnie zachowując wrażliwość metody, przeformułowano metodę analizy hyper-powierzchni trendu i stworzono nowatorski algorytm umożliwiający analizę danych zebranych w kopalni wapienia w Turcji. Jednak że 4-wymiarowe zmienne otrzymane na podstawie danych otworowych ograniczają zasięg analizy powierzchni. W pracy tej porównano zmierzone zawartości CaCO3 otrzymane z 31 otworów z wynikami badań modelowych.