The apparatus of Generalized Nets (GN) is applied here to a description of a selection operator, which is one of the basic genetic algorithm operators. The GN model presented here describes roulette wheel selection. The resulting GN model could be considered as a separate module, but it can also be accumulated into a GN model to describe a whole genetic algorithm.
The aim of this work is to investigate the change of fractal dimension Df with the help of Higuchi Fractal Dimension measure (HFD) in Event-Related Potentials (ERP) of human EEG time series, obtained as a result of oddball paradigm usage and auditory stimulation with instruction for passive listening and counting tasks, depending on gender, personality type and task condition. In our study 77 healthy volunteers have been participated and 38 of them have been selected after a personality classification with Eysenck's personality questionnaire (EPQ).The achieved results showed specific functional meaning of ERP HFD change depending on the individual personality type and gender.
The present work considers Strouma River on the Bulgarian territory using the integral method for evaluation of climatic and anthropogenic impacts on the average annual water volume and maximum and minimum water flow. The level of this impact and risk assessment is determined by the index Mmax, i for the deviation of the maximum water flow from the maximum flow norm Qmax, 0 and the index Mmin, i for the deviation of the minimum water flow from the minimum flow norm Qmin, 0. Using the dynamics of the integral indices Mmax, i, Mmin, i and information on extreme events from the past, a preliminary risk assessment of future extreme events such as floods and draughts could be made. This is done for the first time in risk assessment of extreme events and has been checked at Pernik (in the beginning) and Marino pole (at the border in Greece) for the period 1948 - 2006.
This paper presents a simple digital high-Q bandpass comb filter for power-line (PL) or other periodical interference extraction. The filter concept relies on a correlated signal average resulting in alternating constructive and destructive spectrum interference i.e. the so-called comb frequency response. The presented filter is evaluated by Matlab simulations with real ECG signal contaminated with low amplitude PL interference. The made simulations show that this filter accurately extract the PL interference. It has high-Q notches only at PL odd harmonics and is appropriate for extraction of any kind of odd harmonic interference including rectangular shape. The filter is suitable for real-time operation with popular low-cost microcontrollers.
Summary: The Quasi-Steady-State Approximation (QSSA) theorem is considered as a basic approach for reduction of dimensionality of a dynamical model of microRNA target regulation. On the basis of previously determined parameters, seven ordinary differential equations of the model are written in a form appropriate to evaluate their terms for further reduction. In accordance with the terminology of the QSSA theorem, it is established that five of the system components are fast varying such that the corresponding kinetic equations form an attached system. The other two variables are slow varying and their kinetic equations form a degenerate system.
Ant Colony Optimization is a stochastic search method that mimics the social behaviour of real ant colonies, which manage to establish the shortest routes to feeding sources and backwards. Such algorithms have been developed to reach near-optimum solutions of large-scale optimization problems, for which traditional mathematical techniques may fail. In this paper, a generalized net model of the process of ant colony optimization is constructed and on each iteration intuitionistic fuzzy estimations of the ants' start nodes are made. Several start strategies are developed and combined. This new technique is tested on Multiple Knapsack Problem, which is a real world problem. Benchmark comparisons among the strategies are presented in terms of quality of the results. Based on this comparison analysis, the performance of the algorithm is discussed along with some guidelines for determining the best strategy. The study presents ideas that should be beneficial to both practitioners and researchers involved in solving optimization problems.
In the present work, the characterization and quantification of heterogeneous cardiac repolarization have been considered, and different studies of the authors considering particular aspects of the T-loop morphology have been reviewed. In particular, the longitudinal modifications, the age and gender influences and the diagnostic relations have been reported. The population based ECG-ILSA (Italian Longitudinal Study on Aging) database has been used in all studies. The orthogonal Frank leads were synthesized from the standard 12 lead electrocardiogram. Depending on the different studies, six to ten parameters have been obtained from the vectorcardiograms with two different methods of considering the zero point. The resulting conclusions were: 1. The modified parameters calculated towards the major axis of the T-loop proved to yield higher discriminative power.2. The mean values of all parameters of the T-loop morphology of the healthy subjects group are statistically different from those of ischemia or myocardial infarction groups.3. Stability of the T-loop morphology measurements made in a temporal interval of 5 years (longitudinal modifications) for one and the same patient is observed. The Angina Pectoris group characterized in general by a high "clinical instability" shows the most significant longitudinal modifications.4. Age ( less than 75 years and greater or equal to 75 years old) and gender (male/female) have different T-loop morphology impact in the three considered groups (healthy, cardiac diseases, and hypertension). The gender influences the healthy and patients with hypertension, while age influences mainly the patients with cardiac diseases.
The application of serious gaming technology in different areas of human knowledge for learning is raising the question of quantitative measurement of the training process quality. In the present paper a pilot study of 10 healthy volunteers' EEG spectra is performed for ad hoc selected game events ('win' and 'lose') via continuous wavelet transform (real and complex) on the basis of the Morlet mother wavelet function and S-transformation. The results have shown a general decrease of the alpha rhythms power spectra frequencies for the 'lose' events and increase for the 'win' events. This fact corresponds to an opposite behaviour of the theta rhythm of the players for the same 'win' and 'lose' events. Additionally, the frequency changes in the alpha1 (8-10.5 Hz), alpha2 (10.5-13 Hz) and theta2 rhythms (6-8 Hz) were supposed to be a phenomena related to positive and negative emotions appearance in the EEG activity of the players regarding the selected 'win' and 'lose' states.
Rilska River is one of the left tributaries of Struma River and it is a substantial source of drinking water for the capital city of Sofia. In spite of that the hydrobiological data are quite poor, especially these concerning bottom invertebrate fauna. This study presents the results from research on the macrozoobenthos species composition carried out in 2007-2008 at six sites along the river. During the study period totally 192 benthic taxa were found. The relatively high taxa richness and the presence of species sensitive to pollution at all investigated sites are indicative of stable low-saprobic conditions in the river. It was determined that the species composition along the river continuum differed significantly in the upper and lower part of the river and a tendency of increasing species richness downstream the river was observed.
The present paper presents a hybrid model of yogurt starter mixed culture fermentation. The main nonlinearities within a classical structure of continuous process model are replaced by neural networks. The new hybrid model accounts for the dependence of the two microorganisms' kinetics from the on-line measured characteristics of the culture medium - pH. Then the model was used further for calculation of the optimal time profile of pH. The obtained results are with agreement with the experimental once.
Measurement and recording of changes in bioelectrical impedance in vivo has become a widely used method with various clinical applications. It includes basal impedance Zo, relative changes ΔZ or its derivative dZ. Many applications related to cardiac and respiratory function require simultaneous electrocardiogram, impedance cardiogram and/or respiration signals recording and analysis. Accurate recording of body impedance is limited by high common mode voltages at the amplifier inputs combined with the influence of the output impedance of the used current source. A circuit concept for a simultaneous high-quality electrocardiogram and bioimpedance acquisition is proposed, profiting from advantages offered by a previously specially designed amplifier with current-driven inputs, yielding to low common mode and high differential mode input impedances.
Summary: This article deals with modelling of branched chained amino acids production. One of important branched chained amino acid is L-valine. The aim of the article is synthesis of dynamic unstructured model of fed-batch fermentation process with intensive droppings for L-valine production. The presented approach of the investigation includes the following main procedures: description of the process by generalized stoichiometric equations; preliminary data processing and calculation of specific rates for main kinetic variables; identification of the specific rates takes into account the dissolved oxygen tension; establishment and optimisation of dynamic model of the process; simulation researches. MATLAB is used as a research environment.
Poly-β-hydroxybutyrate (PHB) is an energy-storage polymer whose properties are similar to those of chemical polymers such as polyethylene and polypropylene. Moreover, PHB is biodegradable, absorbed by human tissues and less energy-consuming than synthetic polymers. Although Ralstonia eutropha is widely used to synthesize PHB, it is inefficient in utilizing glucose and similar sugars. Therefore a co-culture of R. eutropha and Lactobacillus delbrueckii is preferred since the latter can convert glucose to lactate, which R. eutropha can metabolize easily. Tohyama et al. [24] maximized PHB production in a well-mixed fed-batch bioreactor with glucose and (NH4)2SO4 as the primary substrates. Since production-scale bioreactors often deviate from ideal laboratory-scale reactors, a large bioreactor was simulated by means of a dispersion model with the kinetics determined by Tohyama et al. [24] and dispersion set at an optimum Peclet number of 20 [32]. The time-dependent feed rates of the two substrates were determined through a genetic algorithm (GA) to maximize PHB production. This bioreactor produced 22.2% more PHB per liter and 12.8% more cell mass than achieved by Tohyama et al. [24]. These results, and similar observations with other fermentations, indicate the feasibility of enhancing the efficiency of large nonideal bioreactors through GA optimizations.
A common problem in statistics is finding a distribution that fits to a certain dataset. Many theoretical distributions have been developed to give a good description of the empirical observations, and consequently, theory offers a variety of algorithms to test the quality of the resulting fits. It is reasonable to expect that each set of measurements should be described with the same theoretical distribution if one and the same experimental mechanism was applied. This paper presents procedures to find a theoretical distribution that best fits to several datasets. The procedure goes further, answering the questions of whether the given datasets come from the same general population, and assessing if the difference between the fitted distributions of two datasets are statistically significant. Kuiper test is used in all steps of the analysis. In two of those a Monte Carlo simulation procedure is elaborated to construct the Kuiper statistic's distribution. A platform with original program functions in MATLAB R2009a is created on the basis of the described procedures. It is applied to datasets from a biochemical experiment, which investigates the resulting density of fibrin network under different thrombin concentrations. The developed procedure has wide applications in different fields, as it models the behavior of datasets, generated through the same mechanism. The possibility to fit one type of distribution over different datasets allows comparing samples, performing interpolation and extrapolation procedures, and investigating the influence of the input conditions of an experiment over the parameters of the fitted distributions.
The paper deals with identifiability and observability of anaerobic digestion (AD) processes. In such kind of processes, generally carried out in continuously stirred tank bioreactors, the organic matter is depolluted by microorganisms into biogas and compost in the absence of oxygen. The biogas is an additional energy source, which can replace fossil fuel sources. The differential algebraic approach of general observation problems has been applied to investigate the identification and observation of a simple AD model. The major discovery is that the biomass specific growth rate can be stably estimated from easily measured quantities: the dilution rate and the biogas flow rate. Next if the yield coefficients are assumed known then, of course, the biomass concentration is observable. Unfortunately, even under the latter strongest assumption the substrate concentration is not observable. This concentration becomes observable if an additional model, say the Monod model, is assumed for the specific growth rate. Illustrative simulations are presented.
Summary: A generalized net model has been developed of the process of discovery of hidden knowledge patterns in databases, which defines the necessary consequence of activities in order to extract knowledge from the input data. The suggested approach is applied to systems for storage and processing of medical data.
Hard-strength training induces strength increasing and muscle damage, especially after eccentric contractions. Eccentric contractions also lead to muscle adaptation. Symptoms of damage after repeated bout of the same or similar eccentrically biased exercises are markedly reduced. The mechanism of this repeated bout effect is unknown. Since electromyographic (EMG) power spectra scale to lower frequencies, the adaptation is related to neural adaptation of the central nervous system (CNS) presuming activation of slow-non-fatigable motor units or synchronization of motor unit firing. However, the repeated bout effect is also observed under repeated stimulation, i.e. without participation of the CNS. The aim of this study was to compare the possible effects of changes in intracellular action potential shape and in synchronization of motor units firing on EMG power spectra. To estimate possible degree of the effects of central and peripheral changes, interferent EMG was simulated under different intracellular action potential shapes and different degrees of synchronization of motor unit firing. It was shown that the effect of changes in intracellular action potential shape and muscle fibre propagation velocity (i.e. peripheral factors) on spectral characteristics of EMG signals could be stronger than the effect of synchronization of firing of different motor units (i.e. central factors).
In the paper is presented preferences based control design and stabilization of the growth rate of fed-batch cultivation processes. The control is based on an enlarged Wang-Monod-Yerusalimsky kinetic model. Expected utility theory is one of the approaches for utilization of conceptual information (expert preferences). In the article is discussed utilization of stochastic machine learning procedures for evaluation of expert utilities as criteria for optimization.
Cardio-pulmonary resuscitation (CPR) is a life-saving first aid which is part of the treatment given in case of sudden cardiac death. According to the American Heart Association (AHA) 2005 Guidelines for CPR, there are three key components related to the chest compressions which should be considered: (i) optimal compression depth between 3.8 and 5.4 centimeters; (ii) optimal compression rate between 85 and 115 compressions per minute; (iii) complete chest recoil by releasing all pressure from the chest after each chest compression (CC).A device for automatic control of the quality of chest compressions during CPR was developed. It embedded hardware and software solutions for simultaneous measurement of the depth, rate and the chest recoil thus providing a feedback about the efficiency of the cardiac massage at each CC compression. The system is applicable as a training device for basic education in CPR or as a consulting system for rescuers on the scene of the cardiac incident. The accuracy of the CC Device was adjusted by theoretical and experimental calibration, and tested by planned experiments, as well as experiments with a medical team.
The article considers numerical modelling of drug release from HPMC-matrices assuming the main controlling processes are diffusion of water and drug and swelling of the matrix. A detailed mathematical description of matrix swelling, connected with the free boundary conditions of the arisen model problem, is introduced. A numerical approach to solution of the posed nonlinear 2D problem is developed on the basis of finite element domain approximation and time difference method. It is implemented in noncommercial software which is used for numerical simulation of fractional drug release under various shapes and sizes of the tablets. This investigation of the effect of aspect ratio (radius/height) and sizes of HPMC tablets on drug release is an inexpensive and effective tool to modify the release kinetics . The proposed numerical approach enables further generalization of the model and performing more profound investigations of the effect of the initial drug loading, matrix erosion and type of release medium.
