Pub Date : 2010-04-21DOI: 10.1109/BIYOMUT.2010.5479742
Omer Kayaalti, B. H. Aksebzeci, M. H. Asyali, O. Karahan, K. Deniz, M. Ozturk
Liver with cirrhosis emerges when the cells of liver begin to die and the tissues become a functional knot from these. In the diagnosis of fibrosis, the needle biopsy is a golden standard. Although this technique is a good techique in reaching accurate diagnosis, its being an invasive method arises disadvantage. The developments in medical image processing and artificial intelligence techniques have advanced the potential of using diagnosis system in classification of liver tissues. In this study, we have aimed at producing some objective measures using image analysis, which will be of assistance in the diagnosis of cirrhosis. In order to differentiate between regions of liver with cirrhosis and healthy parenchymal tissues, we have used first order statistical texture features and second order texture features computed from gray level cooccurrence matrix of liver computerized tomography (CT) images. Then liver CT images of healthy people and people with cirrhosis have been classified with support vector machines (SVM) by using all these acquired features. The most successful classification has been calculated as 85.19% with the method of 10 fold cross-validation.
{"title":"Texture analysis of liver cirrhosis","authors":"Omer Kayaalti, B. H. Aksebzeci, M. H. Asyali, O. Karahan, K. Deniz, M. Ozturk","doi":"10.1109/BIYOMUT.2010.5479742","DOIUrl":"https://doi.org/10.1109/BIYOMUT.2010.5479742","url":null,"abstract":"Liver with cirrhosis emerges when the cells of liver begin to die and the tissues become a functional knot from these. In the diagnosis of fibrosis, the needle biopsy is a golden standard. Although this technique is a good techique in reaching accurate diagnosis, its being an invasive method arises disadvantage. The developments in medical image processing and artificial intelligence techniques have advanced the potential of using diagnosis system in classification of liver tissues. In this study, we have aimed at producing some objective measures using image analysis, which will be of assistance in the diagnosis of cirrhosis. In order to differentiate between regions of liver with cirrhosis and healthy parenchymal tissues, we have used first order statistical texture features and second order texture features computed from gray level cooccurrence matrix of liver computerized tomography (CT) images. Then liver CT images of healthy people and people with cirrhosis have been classified with support vector machines (SVM) by using all these acquired features. The most successful classification has been calculated as 85.19% with the method of 10 fold cross-validation.","PeriodicalId":180275,"journal":{"name":"2010 15th National Biomedical Engineering Meeting","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127416621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-21DOI: 10.1109/BIYOMUT.2010.5479798
Gökhan Baş, G.K. Demir
This study involves a two-step approach to the stitching of images taken for virtual microscopy application. The method has a sub-pixel resolution. To achieve this, first, a coarse shift level is adopted via a correlation function, and then a sinc interpolation is applied to the small neighborhood region of this coarse point. At the end, the sub-pixel shift level is determined by obtaining the maximum of the interpolated function using a gradient descent algorithm. Image stitching process is finalized with linear blending. Results are obtained within the range of ten percent subpixel tolerance.
{"title":"Sinc interpolating approach to sub-pixel image stitching for virtual microscopy","authors":"Gökhan Baş, G.K. Demir","doi":"10.1109/BIYOMUT.2010.5479798","DOIUrl":"https://doi.org/10.1109/BIYOMUT.2010.5479798","url":null,"abstract":"This study involves a two-step approach to the stitching of images taken for virtual microscopy application. The method has a sub-pixel resolution. To achieve this, first, a coarse shift level is adopted via a correlation function, and then a sinc interpolation is applied to the small neighborhood region of this coarse point. At the end, the sub-pixel shift level is determined by obtaining the maximum of the interpolated function using a gradient descent algorithm. Image stitching process is finalized with linear blending. Results are obtained within the range of ten percent subpixel tolerance.","PeriodicalId":180275,"journal":{"name":"2010 15th National Biomedical Engineering Meeting","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127796858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-21DOI: 10.1109/BIYOMUT.2010.5479788
A. Duru, G. Akdeniz, E. Kara, Ç. Özkara, M. Uzan, A. Ademoglu, T. Demiralp
Epilepsy is one of the most common diseases related to the disfunctioning of the central nervous system. For the patients whose drug therapy turns out to be ineffective, it is a common method to identify the locations of sources that trigger the seizure in the brain tissue and resect them through surgical means for treatment. The success of the surgical operation depends on the accurate localization of the foci. Spatial location of the epileptic foci in the brain can be determined by solving the inverse problem using the EEG and SDE measurements. In this study, a source localization validation is performed using the surface and cortex electrical measurements of an epilepsy patient who has underwent a resection operation.
{"title":"Epileptic source localizations based on EEG and SDE measurements","authors":"A. Duru, G. Akdeniz, E. Kara, Ç. Özkara, M. Uzan, A. Ademoglu, T. Demiralp","doi":"10.1109/BIYOMUT.2010.5479788","DOIUrl":"https://doi.org/10.1109/BIYOMUT.2010.5479788","url":null,"abstract":"Epilepsy is one of the most common diseases related to the disfunctioning of the central nervous system. For the patients whose drug therapy turns out to be ineffective, it is a common method to identify the locations of sources that trigger the seizure in the brain tissue and resect them through surgical means for treatment. The success of the surgical operation depends on the accurate localization of the foci. Spatial location of the epileptic foci in the brain can be determined by solving the inverse problem using the EEG and SDE measurements. In this study, a source localization validation is performed using the surface and cortex electrical measurements of an epilepsy patient who has underwent a resection operation.","PeriodicalId":180275,"journal":{"name":"2010 15th National Biomedical Engineering Meeting","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129857366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-21DOI: 10.1109/BIYOMUT.2010.5479752
L. N. Polat, M. Kahriman, S. Çömlekçi
In this study, it is aimed to evaluate SAR value occurred in human head in 1800 MHz. First, 3-D basic model of human head was designed by using HFSS (ANSOFT). So, some solutions were obtained from created model with putting source of 1800 MHz electric field in different orientations on 3-plane. This basic approach shows a close agreement with realistic ones.
{"title":"Creating head model by using 3-D pattern and evaluation of SAR mapping with numerical methods","authors":"L. N. Polat, M. Kahriman, S. Çömlekçi","doi":"10.1109/BIYOMUT.2010.5479752","DOIUrl":"https://doi.org/10.1109/BIYOMUT.2010.5479752","url":null,"abstract":"In this study, it is aimed to evaluate SAR value occurred in human head in 1800 MHz. First, 3-D basic model of human head was designed by using HFSS (ANSOFT). So, some solutions were obtained from created model with putting source of 1800 MHz electric field in different orientations on 3-plane. This basic approach shows a close agreement with realistic ones.","PeriodicalId":180275,"journal":{"name":"2010 15th National Biomedical Engineering Meeting","volume":"434 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122823571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-21DOI: 10.1109/BIYOMUT.2010.5479791
Koray Özkan, N. G. Gencer
The method of contactless conductivity imaging is based on the magnetic-induction magnetic-measurement principle. In this study, the sensitivity of the circular coil used for measuring magnetic fields, to conductivity changes is investigated. To do so, the electrical circuit model of the receiver coil and that of the conductive object is developed. The conductive object is modelled as a thin disk (cylinder) coaxially placed inside the circular coil. Another cylindrical object is assumed to be coaxially placed within the conductive object. It is assumed that, the conductive object is placed within a time varying but spatially constant magnetic field. An analytic formulation is developed for the determination of the sensitivity of the circular coil to the variations of the radius and conductivity of the second object (inhomogeneity). The validity of the model is tested with numerical simulations employing the ANSYS magnetic simulation software. The nonlinearity error between the analytic and numerical solutions is calculated as 1.38% of the full scale for β=0.1, and 11.2% of the full scale for β=0.2.
{"title":"Sensitivity of circular coils to conductivity changes: Analytical and numerical solutions","authors":"Koray Özkan, N. G. Gencer","doi":"10.1109/BIYOMUT.2010.5479791","DOIUrl":"https://doi.org/10.1109/BIYOMUT.2010.5479791","url":null,"abstract":"The method of contactless conductivity imaging is based on the magnetic-induction magnetic-measurement principle. In this study, the sensitivity of the circular coil used for measuring magnetic fields, to conductivity changes is investigated. To do so, the electrical circuit model of the receiver coil and that of the conductive object is developed. The conductive object is modelled as a thin disk (cylinder) coaxially placed inside the circular coil. Another cylindrical object is assumed to be coaxially placed within the conductive object. It is assumed that, the conductive object is placed within a time varying but spatially constant magnetic field. An analytic formulation is developed for the determination of the sensitivity of the circular coil to the variations of the radius and conductivity of the second object (inhomogeneity). The validity of the model is tested with numerical simulations employing the ANSYS magnetic simulation software. The nonlinearity error between the analytic and numerical solutions is calculated as 1.38% of the full scale for β=0.1, and 11.2% of the full scale for β=0.2.","PeriodicalId":180275,"journal":{"name":"2010 15th National Biomedical Engineering Meeting","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125438686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-21DOI: 10.1109/BIYOMUT.2010.5479870
Koray Gürkan, E. Özer
Supercapacitors are commonly used as a back-up or an instant high power source in power electronics applications. This paper presents realization of a floating uninterrupted DC voltage source using supercapacitors. An effective active circuit that equalizes cell voltage of the series connected supercapacitors is also developed.
{"title":"Floating power supply with supercapacitors","authors":"Koray Gürkan, E. Özer","doi":"10.1109/BIYOMUT.2010.5479870","DOIUrl":"https://doi.org/10.1109/BIYOMUT.2010.5479870","url":null,"abstract":"Supercapacitors are commonly used as a back-up or an instant high power source in power electronics applications. This paper presents realization of a floating uninterrupted DC voltage source using supercapacitors. An effective active circuit that equalizes cell voltage of the series connected supercapacitors is also developed.","PeriodicalId":180275,"journal":{"name":"2010 15th National Biomedical Engineering Meeting","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124088577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-21DOI: 10.1109/BIYOMUT.2010.5479784
E. Yıldırım, A. Koyuncuoğlu, H. Külah
This paper presents a novel electrostatically actuated microvalve for lab-on-a-chip applications, fabricated using surface micromachining techniques. Lab-on-a-chip applications generally involve in-plane microflows. Microvalve mentioned here operates by moving a diaphragm, which is in-plane with the flow, perpendicular to the stream with the help of electrostatic forces. Operating principles and the operation of the valve are presented in the paper.
{"title":"An electrostatic parylene microvalve for lab-on-a-chip applications","authors":"E. Yıldırım, A. Koyuncuoğlu, H. Külah","doi":"10.1109/BIYOMUT.2010.5479784","DOIUrl":"https://doi.org/10.1109/BIYOMUT.2010.5479784","url":null,"abstract":"This paper presents a novel electrostatically actuated microvalve for lab-on-a-chip applications, fabricated using surface micromachining techniques. Lab-on-a-chip applications generally involve in-plane microflows. Microvalve mentioned here operates by moving a diaphragm, which is in-plane with the flow, perpendicular to the stream with the help of electrostatic forces. Operating principles and the operation of the valve are presented in the paper.","PeriodicalId":180275,"journal":{"name":"2010 15th National Biomedical Engineering Meeting","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117198682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-21DOI: 10.1109/BIYOMUT.2010.5479733
O. Civalek, B. Akgöz
In the present study, a single elastic beam model based on nonlocal elasticity theory is presented for free vibration analysis of microtubules. The small scale effect is taken into consideration using the Eringen's nonlocal elasticity theory in conjunction with the different types of beam model such as Euler-Bernoulli, Timoshenko, Levinson and Reddy. Numerical results are given to show the size effect on vibration of microtubules.
{"title":"Mechanical modeling of microtubules based on nonlocal continuum theory","authors":"O. Civalek, B. Akgöz","doi":"10.1109/BIYOMUT.2010.5479733","DOIUrl":"https://doi.org/10.1109/BIYOMUT.2010.5479733","url":null,"abstract":"In the present study, a single elastic beam model based on nonlocal elasticity theory is presented for free vibration analysis of microtubules. The small scale effect is taken into consideration using the Eringen's nonlocal elasticity theory in conjunction with the different types of beam model such as Euler-Bernoulli, Timoshenko, Levinson and Reddy. Numerical results are given to show the size effect on vibration of microtubules.","PeriodicalId":180275,"journal":{"name":"2010 15th National Biomedical Engineering Meeting","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123647398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-21DOI: 10.1109/BIYOMUT.2010.5479840
A. Demir, A. U. Keskin, M. Unsal, A. Bayram
Because blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) pulse sequences have rapidly changing high field gradients, almost all currently available equipment which measure and record the response of a patient to visual or audio stimuli in fMRI employ fiber-optics based systems. In this work we introduce a simple and low cost patient response set up which does not require fiber-optics based sensors and interface. The basis of the method is to transmit an on/off light signal through the RF shielded window of the scanning room. The performance of the proposed measurement set up is tested using fMRI sequences in a 3 Tesla MRI unit.
{"title":"A simple set up for the measurement of patient response time in fMRI","authors":"A. Demir, A. U. Keskin, M. Unsal, A. Bayram","doi":"10.1109/BIYOMUT.2010.5479840","DOIUrl":"https://doi.org/10.1109/BIYOMUT.2010.5479840","url":null,"abstract":"Because blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) pulse sequences have rapidly changing high field gradients, almost all currently available equipment which measure and record the response of a patient to visual or audio stimuli in fMRI employ fiber-optics based systems. In this work we introduce a simple and low cost patient response set up which does not require fiber-optics based sensors and interface. The basis of the method is to transmit an on/off light signal through the RF shielded window of the scanning room. The performance of the proposed measurement set up is tested using fMRI sequences in a 3 Tesla MRI unit.","PeriodicalId":180275,"journal":{"name":"2010 15th National Biomedical Engineering Meeting","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129750108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-21DOI: 10.1109/BIYOMUT.2010.5479781
Balkar Erdoğan, N. G. Gencer
Brain-Computer Interface is an alternative communication system between human and outside world which enables paralyzed and locked-in patients (like Amyotrophic lateral sclerosis - ALS) to communicate with their environment or control some electronic devices like computer using only their brain activity. Over the last two decades, numerous studies have been performed on this title and researchers proposed various applications and methodologies related to BCI research. In this study, a design and implementation of a P300 based BCI is realized. The hardware of the system consists of a 10 channel Electroencephalography (EEG) device which has been developed in our laboratory for BCI research. As the first application of this system, the so called “P300 Speller” of Farwell and Donchin has been chosen. Several statistical signal processing techniques and operational optimizations have been applied to improve the speed-accuracy performance of this spelling application. According to the online experiment results performed to test the practicality of this system, two out of five healthy participants were able to operate the system using only two trial repetitions for the perfect prediction of the target characters (6 seconds). The average and maximum bit rates of the system were measured to be 10.4bits/min and 31.14bits/min respectively. Regarding these results, the developed system has superior performance as compared to most of the P300 based BCI systems in the literature.
脑机接口是人与外界的另一种通信系统，它使瘫痪和闭锁患者(如肌萎缩性侧索硬化症)仅通过大脑活动就能与周围环境进行通信或控制计算机等电子设备。在过去的二十年中，对这个题目进行了大量的研究，研究人员提出了与脑机接口研究相关的各种应用和方法。本研究实现了基于P300的脑机接口的设计与实现。该系统的硬件由本实验室为脑机接口(BCI)研究开发的10通道脑电图(EEG)设备组成。作为该系统的第一个应用，选择了Farwell and Donchin的“P300拼写器”。已经应用了几种统计信号处理技术和操作优化来提高这个拼写应用程序的速度-准确性性能。根据测试该系统实用性的在线实验结果，五名健康参与者中有两名能够使用该系统，只需重复两次试验即可完美预测目标字符(6秒)。系统的平均和最大比特率分别为10.4bits/min和31.14bits/min。根据这些结果，与文献中大多数基于P300的BCI系统相比，所开发的系统具有优越的性能。
{"title":"A realization of a P300 based Brain-Computer Interface system","authors":"Balkar Erdoğan, N. G. Gencer","doi":"10.1109/BIYOMUT.2010.5479781","DOIUrl":"https://doi.org/10.1109/BIYOMUT.2010.5479781","url":null,"abstract":"Brain-Computer Interface is an alternative communication system between human and outside world which enables paralyzed and locked-in patients (like Amyotrophic lateral sclerosis - ALS) to communicate with their environment or control some electronic devices like computer using only their brain activity. Over the last two decades, numerous studies have been performed on this title and researchers proposed various applications and methodologies related to BCI research. In this study, a design and implementation of a P300 based BCI is realized. The hardware of the system consists of a 10 channel Electroencephalography (EEG) device which has been developed in our laboratory for BCI research. As the first application of this system, the so called “P300 Speller” of Farwell and Donchin has been chosen. Several statistical signal processing techniques and operational optimizations have been applied to improve the speed-accuracy performance of this spelling application. According to the online experiment results performed to test the practicality of this system, two out of five healthy participants were able to operate the system using only two trial repetitions for the perfect prediction of the target characters (6 seconds). The average and maximum bit rates of the system were measured to be 10.4bits/min and 31.14bits/min respectively. Regarding these results, the developed system has superior performance as compared to most of the P300 based BCI systems in the literature.","PeriodicalId":180275,"journal":{"name":"2010 15th National Biomedical Engineering Meeting","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127693085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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