Elektrik-Elektronik Mühendisliği Bölümü Koleksiyonu

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https://hdl.handle.net/20.500.12846/477

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Gözlemsel Kozmoloji ve Karanlık Madde Özetkileşimleri
(2019) Çamlıbel, Ali Kazım
24 Şubat 2024’de ansızın aramızdan ayrılmasıyla hepimizi derinden üzen Prof. Dr. Durmuş Ali Demir, Yüksek Enerji Fiziği alanında çalışan ve bu alana yaptığı katkılarıyla uluslararası düzeyde tanınan bir fizikçiydi. Hocamızın anısına yapılacak olan bu konuşmada Hocamız ve çalışma alanları hakkında genel bir bilgi verdikten sonra hayatının büyük kısmını harcadığı süpersimetri ve özellikle ömrünün son 10 yılında üzerine daha yoğun eğildiği Higgs kütlesinin doğallık problemi ve buna bir çare olarak üzerinde çalıştığı oluşkan kütleçekimi teorisine kısaca değinilecektir.
From Quantum Mechanics, Classical Mechanics and Bioinformatics to Artificial Intelligence Studies in Neurodegenerative Diseases
(2021) Habiboğlu, Mehmet Gökhan
This volume provides computational methods and reviews various aspects of computational studies of protein aggregation. Chapters discuss the relationship between protein misfolding and protein aggregation, methods of prediction of aggregation propensities of protein, peptides, protein structure, results of computer simulations of aggregation, and computational simulations focused on specific diseases such as Alzheimer’s, Parkinson’s, and preeclampsia. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls.
Glycopeptides by quantum chemistry and artificial intelligence
(2018) Habiboğlu, Mehmet Gökhan
Glycation destroys or impairs the biological function of peptides and proteins. The bacteria cell wall polymers consist of GlcNAc, which is crosslinked with oligopeptides. While glutamine is a nonessential amino acid that can be derived from glucose, some cancer cells primarily depend on glutamine for their growth, proliferation, and survival. Numerous types of cancer also depend on asparagine for cell proliferation. Thus, glucose and asparagine interactions are at the center of cancer. Moreover, Semliki Forest virus grown in mosquito cells consist of asparagine-linked oligosaccharides. Dengue virus envelope protein (E) consists of two N-linked glyscosylation sites asparagine-67 and asparagine-153. N-linked oligosaccharide side chains on flavivirus E proteins have been associated with viral morphogenesis, infectivity, and tropism. Virologically, ZIKV consists of a single-stranded, positive-sense RNA while the genome encodes three structural proteins including an E protein. Both cryo-electron microscopy and crystallization measurements supported the role of asparagine as a glycosylation site for host cell attachment.
Katkı malzemelerinin polimerik yalıtkanların manyetik geçirgenliğine etkisinin incelenmesi
(2020-2021) Nişancı, Salih
[Özet yok]
A Machine Learning Approach to Predict the Sepsis Status: Analyzing the Connection Between Relevant Laboratory Values and Other Physiological Measurements Obtained in Intensive Care Unit
(2021) Moghaddamnia, Sanam; Bozkurt, Mehmet Recep
Sepsis is a life-threatening disease caused by the body's response to an infection, which leads to tissue damage, organ failure and death. According to literature, about 1.7 million Americans each year suffer from sepsis with approximately 270,000 fatal cases, and more than one third of mortalities in hospitals are associated with sepsis. It is estimated that worldwide about 30 million people suffer from sepsis each year, and 6 million patients with sepsis die. Above all, the cost of sepsis care is extremely high and constitutes a health risk mostly in developing countries. Having regard to the above, early diagnosis and therapy of sepsis play a key role in increasing the chance of cure for many patients. In this regard, many clinicians and researchers have proposed new definitions for sepsis (Singer et al. 2016), however the subject of early diagnosis methods and their practical usability and limits for sepsis remains to a large extent unexplored. Therefore, a cost-effective self-diagnostic technic has been proposed in this work, which is based on the XGBoost algorithm and deep convolution neural network model for sepsis prediction. Septic data were used for the model training, and the highest accuracy and the area under the ROC curve (AUC) obtained to evaluate the performance of the model were 96.49% and 70.78%, respectively. The novelty of this study lies in the investigations that unlike other studies are performed using vital signs determined independently from laboratory measurements. It has shown that the proposed model is faster and can provide more accurate results, and thus has great potential to be used as an efficient technique in predicting sepsis.
On the efficiency of LSTM in classifying musical impressions from EEG recordings
(2023) Kaya, Burak; Habiboğlu, Mehmet Gökhan; Moghaddamnia, Sanam
The objective of this study is the classification of musical impressions with long short-term memory (LSTM) approach using EEG recordings of 20 subjects, while listening to different music genres. For this purpose, a deep learning model was developed, where relevant features extracted from intrinsic mode functions (IMF) of the clean EEG data are used as the input signals. The classification accuracy of the proposed model is evaluated with various feature sets. The highest classification accuracy is 73.33%, which is achieved by combining higher-order statistics and the first difference of IMF features.
Parameter and feature selection in decision trees for the classification of musical impressions from EEG records
(2023) Ozaltun, Emir Atakan; Moghaddamnia, Sanam; Habiboğlu, Mehmet Gökhan
Reliable classification of different emotions is an important issue for emotional interaction between humans and computers. Therefore, this study aims at assessing the performance of decision trees in classifying musical impressions from EEG records of 20 subjects, who listened to songs in different music styles. First, features extracted from the clean EEG data used to train the classifier, where different feature combinations and parameter settings are considered. Next, the impact of various hyperparameter values on the classification accuracy is examined and the relevant feature combination is specified. According to the results, an accuracy rate of 76,12% is achieved, when all time domain features are included in the classification.
A mathematical computer model for estimating phase weight/ atomic fractions for iron slags’ system (SiO2-Al203-CaO-MgO) at subsolidus temperatures
(Springer, 2023) Yelkenci, Tanju; Erkmen, Z. Engin
In this study, the 3 dimensional description of the quaternary subsolidus slag system aluminasilicacalciamagnesia is evaluated using Mathematica programming based on previous experimental research data. The lever rule in the tetrahedra is then applied for a given arbitrary liquid composition %A ? %B ? %C ? %D = 100 in order to calculate the solid phases present (neglecting solid solutions) with their relative proportions after the solidification is completed. A novel transformation and algorithm are then developed using simple geometry and Matlab programming which can also be used for other subsolidus systems in case appropriate data are provided.
Ayrık sinyaller
(Palme Yayınevi, 2022) Civelek, Cem
Ayrık Sinyaller kitabında ülkemiz öğrencilerine ana dillerinde temel bilgi vermeyi hedefle miştir. Ana dilimizde yeterli kaynak olmadığı ve öğrencilerin yabancı dil bilgilerinin yetersizliği de göz önüne alındığında ana dildeki kaynakların ne kadar önemli olacağı ortaya çıkmaktadır. Ancak adından da anlaşılacağı üzere bu kitap, giriş düzeyinde de olsa bir ANALİZ kitabıdır ve buna bağlı olarak göreceli fazla matematik ve kuramsal bilgi içermeyi amaçlamıştır.
Devre analizi 1
(Seçkin Yayıncılık, 2022) Civelek, Cem
Uzun yıllar Almanya'da akademisyenlik yapan, sonrasında Türkiye'de akademik kariyerine devam eden Prof. Dr. Cem CİVELEK'in kaleme aldığı kitap, yazarın ders anlatım tecrübesinden ve kendisine gelen soruların ve sorunların çözümlerinden oluşmaktadır. Kitap üniversitelerin Mühendislik Bölümlerinde okuyan öğrencilerin " Devre Analizi 1", "Elektrik Devre Analizi 1" ders içeriklerine uygun olarak uygulamalı ve örnek çözümlü olarak hazırlanmış olup, öğrencilerin anlayabileceği yalınlıkta hazırlanmıştır. Kitap, sadece anlatımı sayesinde ders kitabı olarak hazırlanmış olmasına karşın kendini Devre Analizi konusunda geliştirmek isteyenlere de kaynak olacaktır. İlgili dersin devam konularına, kitabın ikinci cildinde "Devre Analizi 2" de ulaşabilirsiniz. Kitabın bir diğer özelliği, içindekiler kısmında bölüm isimlerinin İngilizcesine yer verilmesidir. Böylece, bu dersi İngilizce görenlerin aradıkları konunun Türkçesine ulaşmaları kolaylaşacaktır.
Devre analizi 2
(Seçkin Yayıncılık, 2022) Civelek, Cem
Uzun yıllar Almanya'da akademisyenlik yapan, sonrasında Türkiye'de akademik kariyerine devam eden Prof. Dr. Cem CİVELEK'in kaleme aldığı kitap, yazarın ders anlatım tecrübesinden ve kendisine gelen soruların ve sorunların çözümlerinden oluşmaktadır. Kitap üniversitelerin Mühendislik Bölümlerinde okuyan öğrencilerin " Devre Analizi 2", "Elektrik Devre Analizi 2" ders içeriklerine uygun olarak uygulamalı ve örnek çözümlü olarak hazırlanmış olup, öğrencilerin anlayabileceği yalınlıkta hazırlanmıştır. Kitap, sadece anlatımı sayesinde ders kitabı olarak hazırlanmış olmasına karşın kendini Devre Analizi konusunda geliştirmek isteyenlere de kaynak olacaktır. İlgili dersin önceki konularına, kitabın birinci cildinde "Devre Analizi 1" de ulaşabilirsiniz. Kitabın bir diğer özelliği, içindekiler kısmında bölüm isimlerinin İngilizcesine yer verilmesidir. Böylece, bu dersi İngilizce görenlerin aradıkları konunun Türkçesine ulaşmaları kolaylaşacaktır.
Weak field and slow motion limits in energy–momentum powered gravity
(Elsevier BV, 2023) Çamlıbel, Ali Kazım; Akarsu, Özgür; Katırcı, Nihan; Semiz, İbrahim
We explore the weak field and slow motion limits, Newtonian and Post-Newtonian limits, of the energy–momentum powered gravity (EMPG), viz., the energy–momentum squared gravity (EMSG) of the form f (Tµ?T µ? ) = ?(Tµ?T µ? ) ? with ? and ? being constants. We have shown that EMPG with ? ? 0 and general relativity (GR) are not distinguishable by local tests, say, the Solar System tests; as they lead to the same gravitational potential form, PPN parameters, and geodesics for the test particles. However, within the EMPG framework, Mast, the mass of an astrophysical object inferred from astronomical observations such as planetary orbits and deflection of light, corresponds to the effective mass Meff(?, ?, M) = M + Mempg(?, ?, M), M being the actual physical mass and Mempg being the modification due to EMPG. Accordingly, while in GR we simply have the relation Mast = M, in EMPG we have Mast = M + Mempg. Within the framework of EMPG, if there is information about the values of {?, ?} pair or M from other independent phenomena (from cosmological observations, structure of the astrophysical object, etc.), then in principle it is possible to infer not only Mast alone from astronomical observations, but M and Mempg separately. For a proper analysis within EMPG framework, it is necessary to describe the slow motion condition (also related to the Newtonian limit approximation) by |peff/?eff| ? 1 (where peff = p+pempg and ?eff = ? +?empg), whereas this condition leads to |p/?| ? 1 in GR.
Investigation of the effect of layered structure on partial discharges in transformer pressboard insulator
(Springer, 2023) Uğur, Mukden; Atalar, Fatih; Önhon, N.Özben
The dielectric performance of pressboards impregnated with mineral oil is one of the key points in regard to the quality of the transformer’s working life. Partial discharges (PDs) occurring in the pressboard can cause some insulation defects which might be one of the major reasons for an electrical breakdown. Detection of the PDs in pressboards gives a chance to understand the dielectric behavior of the insulators, hence major defects can be prevented just in early stage. The main point of the study is to investigate the differences in dielectric performance of layered and non-layered pressboards in the presence of PDs. For this purpose, the PD behavior of a layered pressboard with three layers (each with a thickness of 0.5 mm) and of a non-layered (solid) pressboard (with a thickness of 1.5 mm) is examined for two different high voltage levels (20 and 30 kV). To detect the PDs, Hall Effect Sensors are employed, considering that PDs cause fluctuations in the magnetic field. To analyze the magnetic field measurements from a statistical point of view, the Kaplan–Meier method and the Weibull analysis are used.
Electromagnetic investigation of neuron growth by using pulsed electromagnetic field stimulation
(Elsevier, 2023) Kara, S.; Uzunoğlu, C. P.; İşçi, E. T.; Atalar, F.; Uğur, Mukden
Electromagnetic field (EMF) applications for humans have been widely used for medical therapy for a long time. Various nerve diseases such as complex regional pain syndrome, cerebral palsy and spinal cord injuries may occur as a result of damage on the nerve cells. In addition, EMF applications are taken into consideration in terms of tissue regeneration. The use of electricity for nerve regeneration is applied internally or externally. The use of direct current (DC) electric fields to stimulate axon elongation and nerve regeneration in nerve cells has been applied in various studies. In our study, electromagnetic field was used for the controlled and directional growth of Dorsal Root Ganglia (DRG) nerve cells. An amplifier circuit, which can produce amplified signals to generate proposed pulsed electromagnetic fields (PEMF) is designed. The electromagnetic field is produced on FR-4 copper plate, which highlights electrical field unlike previous studies, since there is no circular coil structure preferred. The elongation of nerve cells is planned to be in one direction, hence the signal to be applied is produced as a novel asymmetrical waveform (sawtooth) in addition to triangular and square waveforms which were previously preferred in recent studies. By the aid of proposed novel construction and produced signal waveform, PEMF system can be applied for nerve diseases effectively. The morphological nerve cell elongation results and PEMF results have been investigated and the effectiveness of the proposed system is verified.
Functional quality assessment of whole-body vibration training devices based on instantaneous amplitude and frequency of photogrammetric vibration measurements
(Medical Engineering & Physics, 2023) Moghaddamnia, Sanam; Rofallski, Robin; Luhmann, Thomas; Kaeding, Tobias S.
The practical use of whole-body vibration training (WBVT) and such research may be negatively influenced by generated vibrations with amplitudes, frequencies, and/or patterns that deviate from preset adjustments on WBVT devices. This study examined whether prolonged regular use can generate respective deviations. Four WBVT devices, used for 19 months in a research project on the effects of WBVT, were analyzed using photo grammetry before start of the research project and after 19 months. Divergences between preset and measured amplitudes and frequencies were calculated for all measurements. To quantify how well the output of devices correlates with the target setting, the vibration characteristics were calculated. In particular, exact long-term measurements related to the vibration amplitude is conducted and analyzed for the first time, which has been found as an important measure of the device functional quality. One device had a significantly (p < 0.01) larger machine run time than the other three. This one showed the most pronounced signs of functional impairments concerning instantaneous amplitudes, frequencies and the mode of vibration after prolonged use. These results based on photometric measurements underline again that prolonged use can result in divergences between preset and actual applied amplitudes, frequencies, mode of vibration and other accuracy measurement metrics.
A stacked multi-sensor platform for real-time MRI guided interventions
(Elsevier, 2023) Zolfaghari, Parviz; Erden, Oğuz K.; Tümer, Murat; Yalçınkaya, Arda D.; Ferhanoğlu, Onur
We present a stacked temperature, pressure, and localization platform, targeted for minimally invasive surgical and diagnostic applications under Magnetic Resonance Imaging. The platform comprises a micro-fabricated three-layer (Titanium-Parylene-Titanium) membrane pressure sensor, a Gallium Arsenide band-gap temperature sensor, and a magnetic material on double prism retro-reflector that benefits from Magneto-Optic Kerr effect as a magnetic field sensor, to provide localization feedback under Magnetic Resonance Imaging. All sensors can be addressed with a single fiber optic cable, where the collected light is directed to a spectrometer and a polarimeter. For the three-layer microfabricated membrane sensor, an analytical formulation is derived, linking the pressure to optical intensity. Moreover, finite-element simulation results are provided, verifying analytical findings. Wavelength division multiplexing is exploited to address the sensors simultaneously. We measured sensitivities of 0.025 millidegree/Gauss rotation of polarization, 1.5 nm/mmHg displacement (in agreement with simulation results and analytical findings), 0.36 nm/degrees C. bandgap wavelength shift for magnetic field, pressure, and temperature sensors; respectively. With further development, the proposed device can be adapted to a clinical setting for use in Magnetic Resonance assisted surgical procedures.
Investigation of the effects of additives on the electrical and magnetic properties of polyester resin
(Istanbul University Cerrahpaşa, 2022) Nişancı, Salih; İpekoglu, Mehmet; Nişancı, Muhammet Hilmi; Karhan, Mustafa; Uğur, Mukden
Polymers are widely used as insulation materials in the electrical industry because their existing electrical and mechanical properties can be altered by adding different types of additives. Successful prediction of the service life of the insulators used in the electrical industry is important for the reliability of the system. For this purpose, insulating materials are subjected to tests according to various standards. In this study, unlike the literature, a polymeric insulator was produced by adding 3 wt.% zinc oxide (ZnO), magnetite (Fe 3O 4), and nickel (Ni) into the polyester. The produced samples were subjected to the inclined plane test in accordance with ASTM (American Society for Testing and Materials) D-2303 standards. In order to analyze the electric and magnetic field distributions formed on the samples during the inclined plane test, first, the current flowing on the samples during the test was measured. Following this, analyses were carried out by creating a simulation model of the samples. Studies found in the literature mainly focus on two-dimensional investigation of the electrical field distribution. This study concentrates on the three-dimensional examination of the electrical field also considering the magnetic field distribution. Results of this study showed that prior numerical analysis gives insight into information about the real-life behavior of the samples.
Observability, controllability and stability of a nonlinear RLC circuit in form of a Duffing oscillator by means of theoretical mechanical approach
(Slovak University of Technology in Bratislava, 2022) Civelek, Cem
In this research article, observability, controllability and stability of a nonlinear RLC circuit with a nonlinear capacitor is investigated as a Duffing oscillator beginning with the dissipative equations of generalized motion using Lagrange-dissipative model ({L, D}-model briefly). The force related to the potential energy, equilibria, and their well known stability properties are given using state space approach. Prerequisite that the condition for a Legendre transform is fulfilled, for the same system, also Hamiltonian of the system is found. Using Hamiltonian and dissipation function, dissipative canonical equations are obtained. These equations are written in state space form. Then the equality to the same results obtained using the dissipative equations of generalized motion related equilibria and their stability was shown. Thus a Lyapunov function as residual energy function (REF) is justified in terms of stability of the overall system. As last step, different electrical and mechanical (physical) realization possibilities are discussed.
Physical system analysis related to observability, controllability and stability using its equations of generalized motion and canonical equations both in dissipative forms
(Springer, 2022) Civelek, Cem; Suesse, Roland
Using tensorial variables in contravariant, covariant forms and different formulation types, the reader is informed about a coupled physical nonlinear system with f degree of freedom. f second-order differential equations of dissipative generalized motion obtained by the extended Euler-Lagrange differential equations can be transformed to a system of 2f differential equations of order one using the theory of state variables or Hamiltonian approaches. Besides analyzing the system, these equations can also be used to analyze such a system in terms of observability, controllability and stability. In this article, another property of Lagrange-Dissipative system modeling ({L, D}-modeling briefly) is presented. And thus, this sort of modeling approach of physical/engineering systems are enriched by means of observability, controllability applying Lie algebra, which has the classical observability and controllability matrices of the linear case. Stability analysis is also performed. Using Lagrangian and Hamiltonian approaches together with dissipation, one can obtain the state equations for a system in an easy way. Moreover, different forms in different formulation types of state equations can be presented. How these forms are achieved is also explained. The approach is convenient specially when using coupled systems, where different physical quantities are available together. The only restriction compared to the classical state space analysis is that the generalized coordinate (and momentum) depending on formulation must be selected as the state variable. A coupled electromechanical example in different forms and formulations is given.
Shape investigations of structures formed by the self-assembly of aromatic amino acids using the density-based spatial clustering of applications with noise algorithm
(Scientific & Technical Research Council Turkey-TUBITAK, 2022) Habiboğlu, Mehmet Gökhan; Hernandez, Helen W.; Uyaver, Şahin
Tyrosine, tryptophan, and phenylalanine are important aromatic amino acids for human health. If they are not properly metabolized, severe rare mental or metabolic diseases can emerge, many of which are not researched enough due to economic priorities. In our previous simulations, all three of these amino acids are discovered to be self-organizing and to have complex aggregations at different temperatures. Two of these essential stable formations are observed during our simulations: tubular-like and spherical-like structures. In this study, we develop and implement a clustering analyzing algorithm using density-based spatial clustering of applications with noise (DBSCAN) to measure the shapes of the formed structures by the self-assembly processes of these amino acids. We present the results in quantitative and qualitative ways. To the best of our knowledge, the geometric shapes of the formed structures by the self-assembly processes of these amino acids are not measured quantitatively in the literature. Analytical measurements and comparisons of these aggregations might help us to identify the self-aggregations quickly at early stages in our simulations and hence provide us with more opportunity to experiment with different parameters of the molecular simulations (like temperature, mixture rates, and density). We first implement the DBSCAN method to identify the main self-aggregation cluster and then we develop and implement two algorithms to measure the shapes of the formed structures by the self-assembly processes of these amino acids. The measurements, which are completely in line with our simulation results, are presented in quantitative and qualitative ways.

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