Orhan, Umut | Hekim, Mahmut | Özer, Mahmut | Provaznik, Ivo

Proceedings | 2011 | INISTA 2011 - 2011 International Symposium on INnovations in Intelligent SysTems and Applications , pp.626 - 630

In this paper, the equal frequency discretization (EFD) based probability density approach was proposed to be used in the diagnosis of epilepsy from electroencephalogram (EEG) signals. For this aim, EEG signals were decomposed by using the discrete wavelet discretization (DWT) method into subbands, the coefficients in each subband were discretized to several intervals by EFD method, and the probability density of each subband of each EEG segment was computed according to the number of coefficients in discrete intervals. Then, two probability density functions were defined by means of the curve fitting over the probability densities . . .of the sets of both healthy subjects and epilepsy patients. EEG signals were classified by applying the mean square error (MSE) criterion to these functions. The result of the classification was evaluated by using the ROC analysis, which indicated 82.50% success in the diagnosis of epilepsy. As a result, the EFD based probability density approach may be considered as an alternative way to diagnose epilepsy disease on EEG signals. © 2011 IEEE Daha fazlası Daha az

Orhan, Umut | Hekim, Mahmut | Özer, Mahmut

Article | 2011 | JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY26 ( 3 ) , pp.575 - 580

In this study, we proposed a new feature extraction approach based on equal width discretization (EWD) method and used the statistical features obtained by means of this approach as the inputs of multilayer perceptron neural network (MLPNN) model in the detection of epileptic seizure from Electroencephalogram (EEG) signals. For this aim, EEG signals were discretized by EWD method, histograms of the signals were obtained according to the density of each discrete interval, and finally these histograms were used as the inputs of MLPNN models both without any hidden layer and with a hidden layer which has 5 neurons. Both of them detecte . . .d epileptic seizures from EEG signals with high classification success ratios. This result showed that a linear classifier can also solve the problem of epileptic seizure detection by means of the offered feature extraction approach. Consequently, EWD approach may be used as a new feature extraction method in the biomedical signal processing Daha fazlası Daha az

Orhan, Umut | Hekim, Mahmut | Özer, Mahmut

Article | 2011 | Expert Systems with Applications38 ( 10 ) , pp.13475 - 13481

We introduced a multilayer perceptron neural network (MLPNN) based classification model as a diagnostic decision support mechanism in the epilepsy treatment. EEG signals were decomposed into frequency sub-bands using discrete wavelet transform (DWT). The wavelet coefficients were clustered using the K-means algorithm for each frequency sub-band. The probability distributions were computed according to distribution of wavelet coefficients to the clusters, and then used as inputs to the MLPNN model. We conducted five different experiments to evaluate the performance of the proposed model in the classifications of different mixtures of . . . healthy segments, epileptic seizure free segments and epileptic seizure segments. We showed that the proposed model resulted in satisfactory classification accuracy rates. © 2010 Elsevier Ltd. All rights reserved Daha fazlası Daha az

Yılmaz, Ergin | Özer, Mahmut | Çavuşoğlu, Abdullah

Proceedings | 2011 | INISTA 2011 - 2011 International Symposium on INnovations in Intelligent SysTems and Applications , pp.581 - 584

The channel noise stemming from voltage-gated ion channels, which embedded in excitable neuronal membranes has a great impact on the production and propagation of the action potential in stochastic Hodgkin-Huxley (HH) neurons. In this study, we investigate the effects of sodium and potassium channels blockage and the average degree of connectivity on the spontaneous collective firing regularity on scale-free network which consisting of stochastic HH neurons. The obtained results reveal that potassium channel blockage has constructive effects on the firing regularity whereas sodium channel blockage has disruptive effects on the firin . . .g regularity. On the other hand, the spontaneous firing regularity exhibits coherence resonance depending on both the channel blockage scaling factor and the neuronal membrane area. The results also indicate that there is a lower boundary for the average degree of the network connectivity where the coherence resonance exists when the value of the network connectivity is greater than this lower boundary. © 2011 IEEE Daha fazlası Daha az

Altın, Süreyya | Özgüven, Melih

Article | 2011 | Fresenius Environmental Bulletin20 ( 3 ) , pp.631 - 638

This study analyzed the zinc transport in supported liquid membrane (SLM) systems in which different anionic (Aliquat336) and cationic (D2EHPA) carriers, different solvents (kerosene and toluene) and different feed (deionized water and HCl) / stripping solutions (H3PO4, HCl and H 2SO4) were used. The results were modeled according to steady state (Fick's first law) and non-steady state kinetics approaches and the concordance of the models was discussed. It was observed from the experimental studies that 80.4% zinc transport could be achieved when deionized water was used as feed solution, kerosene/ D2EHPA (0.01 M) as membrane soluti . . .on combination and H3PO4(0.5 M) as stripping solution. Whilst the zinc transport efficiency was found to be 86.5% when HCl (1.0 M) was used as feed solution, toluene-Aliquat336 (0.02 M) as membrane solution combination and HCl (0.5 M) as stripping solution. Modeling studies established that the nonsteady state approach better represented zinc transport. It was therefore concluded that the zinc transport mechanism was affected by interface reactions rather than diffusion. © by PSP Daha fazlası Daha az

Altın, Süreyya | Alemdar, Sonay | Altın, Ahmet | Yıldırım, Yılmaz

Article | 2011 | Separation Science and Technology46 ( 5 ) , pp.754 - 764

Selective removal of cadmium from wastewaters is very important, because cadmium is toxic for the environment and for human health. This work is a comprehensive study on the selective removal of Cd(II) from aqueous solutions by using a co-current flow flat sheet supported liquid membrane system. 4.4 × 10-4M Cd(II) concentration was used as a feed solution in the experiments. Toluene containing Aliquat 336 was used as the membrane liquid in the membrane system. Parameters such as the properties of feed and stripping solutions, carrier concentration, and flow rate, which have roles in transport of Cd(II) ions, were optimized. The effi . . .ciency of the system is expressed in terms of permeability and flux values, and transport efficiency. The optimum process conditions for the Cd(II) transport are experimentally found as follows: The feed solution as 2 M HCl, the carrier concentration as 0.1 M Aliquat 336, the stripping solution as 0.06 M EDTA, and the flow rates for the feed and stripping solutions as 50 mL/min and 80 mL/min, respectively. Under these conditions, the Cd(II) transport efficiency is found to be 82%. © Taylor & Francis Group, LLC Daha fazlası Daha az

Altın, Süreyya

Article | 2011 | INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING9 , pp.754 - 764

This study aims to investigate color and COD removal efficiencies of electrocoagulation (EC) process for dye solutions simulated by using polyvinyl alcohol (PVA) and reactive dyestuff of Remazol Turquoise Blue (G-133). The two different electrode configurations, namely monopolar and bipolar, were examined to find out the better alternative intensifying the performance of the process. The results obtained from these tests show that an EC cell with bipolar electrodes has produced slightly higher color and COD removal efficiencies than that of an EC cell with monopolar electrodes. The best removal efficiencies have been found for the b . . .oth electrode configurations under the conditions that the time of electrolysis is 30 min, the constant direct current (DC) value 0.75 A and the initial pH value 3. Consequently, the bipolar electrode configuration (BPEC) has yielded 72.7 percent COD and 99.8 percent color removals while the monopolar electrode configuration (MPEC) producing 65.2 percent COD and 99.6 percent color removals Daha fazlası Daha az