Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://gcris.khas.edu.tr/handle/20.500.12469/1248

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Citation Count: 5
A 1-kW wireless power transfer system for electric vehicle charging with hexagonal flat spiral coil
(Tubitak Scientific & Technical Research Council Turkey, 2021) Aydin, Emrullah; AydemIr, M. Timur
Wireless power transfer (WPT) technology is getting more attention in these days as a clean, safe, and easy alternative to charging batteries in several power levels. Different coil types and system structures have been proposed in the literature. Hexagonal coils, which have a common usage for low power applications, have not been well studied for high and mid power applications such as in electric vehicle (EV) battery charging. In order to fill this knowledge gap, the self and mutual inductance equations of a hexagonal coil are obtained, and these equations have been used to design a 1 kW WPT system with hexagonal coils for a mid-power stage EV charging. The theoretical and simulation results have been validated with an implementation in the laboratory and a DC-to-DC power efficiency of 85% is achieved across a 10 cm air gap between the perfect aligned coils. The misalignment performance of the system was observed for different positioning of the secondary coil, and the output power variation is given. In addition, the effect of shielding on magnetic field exposition of a driver sitting in an EV was obtained, and these simulation results were compared in order to check the compliance with international health standards.
Citation Count: 2
3D self-assemble formation of molybdenum disulfide (MoS2)-doped polyacrylamide (PAAm) composite hydrogels
(Tubitak Scientific & Technological Research Council Turkey, 2022) Durmaz, Sumeyye; Yildiz, Ekrem; Uysal, Bengu Ozugur; Pekcan, Onder
Polyacrylamide (PAAm), a renowned member of the hydrogel class, has many uses throughout a wide range of industrial processes, including water absorbed diapers, contact lenses, wastewater treatment, biomedical applications such as drug delivery vehicles and tissue engineering because of its physical stability, durability, flexibility easier shaping, and so on. PAAm also provides new functionalities after the incorporation of inorganic structures such as molybdenum disulfide (MoS2). During the copolymerization process, the transmittance of all samples reduced significantly after a particular time, referred to as the gel point. Microgels form a tree above the gel point as projected by Flory-Stockmayer classical theory. Because of microgels positioned at the junction points of the Cayley tree, the addition of MoS2 results in strong intramolecular crosslinking and looser composites. Moreover, fractal geometry provides a quantitative measure of randomness and thus permits characterization of random systems such as polymers. Fractal dimension of these polymer composites is calculated from power-law-dependent scattered intensity. It was also confirmed that a hydrogel rapidly formed within a few seconds, indicating a 3D network formation inside the gel. These materials may have a great potential for application in wearable and implantable electronics due to this highly desired 3D self-assemble feature.
Citation Count: 2
Accented Essays: Documentary as Artistic Practice in Contemporary Audiovisual Works from Turkey
(Routledge, 2019) Akçalı, Elif
This article looks at the use of documentary filmmaking in contemporary artistic practices in Turkey, specifically focusing on three works that adopt a first-person, subjective viewpoint: Didem Pekün’s Of Dice and Men (2016), Şener Özmen’s How to Tell of Peace to a Living Dove? (2015), and Aykan Safoğlu’s Off-White Tulips (2013). Made by artists in transition, these films tackle themes of belonging and identity through stylistic choices proper to essayistic filmmaking, which allow these works to be regarded as accented essays. The personal questions raised through the aesthetics they employ become relevant to collective issues of culture, history, and memory, offering an alternative understanding of the social context, which was largely affected by the political events during the period in which they were made. © 2019, © 2019 Critical Arts.
Citation Count: 4
Accurate indoor positioning with ultra-wide band sensors
(Tubitak, 2020) Arsan, Taner
Ultra-wide band is one of the emerging indoor positioning technologies. In the application phase, accuracy and interference are important criteria of indoor positioning systems. Not only the method used in positioning, but also the algorithms used in improving the accuracy is a key factor. In this paper, we tried to eliminate the effects of off-set and noise in the data of the ultra-wide band sensor-based indoor positioning system. For this purpose, optimization algorithms and filters have been applied to the raw data, and the accuracy has been improved. A test bed with the dimensions of 7.35 m x 5.41 m and 50 cm x 50 cm grids has been selected, and a total of 27,000 measurements have been collected from 180 test points. The average positioning error of this test bed is calculated as 16.34 cm. Then, several combinations of algorithms are applied to raw data. The combination of Big Bang-Big Crunch algorithm for optimization, and then the Kalman Filter have yielded the most accurate results. Briefly, the average positioning error has been reduced from 16.34 cm to 7.43 cm.
Citation Count: 11
Accurate Refinement Of Docked Protein Complexes Using Evolutionary Information And Deep Learning
(Imperıal College Press, 2016) Akbal-Delibas, Bahar; Farhoodi, Roshanak; Pomplun, Marc; Haspel, Nurit
One of the major challenges for protein docking methods is to accurately discriminate native-like structures from false positives. Docking methods are often inaccurate and the results have to be refined and re-ranked to obtain native-like complexes and remove outliers. In a previous work we introduced AccuRefiner a machine learning based tool for refining protein-protein complexes. Given a docked complex the refinement tool produces a small set of refined versions of the input complex with lower root-mean-square-deviation (RMSD) of atomic positions with respect to the native structure. The method employs a unique ranking tool that accurately predicts the RMSD of docked complexes with respect to the native structure. In this work we use a deep learning network with a similar set of features and five layers. We show that a properly trained deep learning network can accurately predict the RMSD of a docked complex with 1.40 angstrom error margin on average by approximating the complex relationship between a wide set of scoring function terms and the RMSD of a docked structure. The network was trained on 35000 unbound docking complexes generated by RosettaDock. We tested our method on 25 different putative docked complexes produced also by RosettaDock for five proteins that were not included in the training data. The results demonstrate that the high accuracy of the ranking tool enables AccuRefiner to consistently choose the refinement candidates with lower RMSD values compared to the coarsely docked input structures.
Citation Count: 12
Acute aortic valve regurgitation secondary to blunt chest trauma
(Texas Heart Inst., 2001) Ünal, Mehmet; Demirsoy, Ergun; Göğüş, Abdullah; Arbatlı, Harun; Hamzaoğlu, Azmi; Sönmez, Bingür
Blunt injury to the cardiac valves leads to progressive acute ventricular failure which often requires urgent surgical management In this case report we describe an acute aortic valve rupture caused by air-bag inflation during an automobile accident. Laceration of an aortic valve cusp was treated successfully with urgent aortic valve replacement. A concomitant orthopedic injury was treated electively 15 days after cardiac surgery. Acute aortic valve rupture is a very rare complication of blunt chest trauma. We discuss how to diagnose and manage this potentially catastrophic event.
Citation Count: 10
Acute gastrointestinal complications after open heart surgery
(Asia Publishing Exchange Pte Ltd, 2000) Akpınar, Belhhan; Sağbaş, Ertan; Güden, Mustafa; Kemertas, Kubilay; Sönmez, Bingür; Bayındır, Osman; Demiroğlu, Cemşid
Retrospective analysis revealed that 24 of 4401 adult patients (0.5%) developed severe gastrointestinal complications after open heart surgery during a 3-year period from January 1995. There were 4 women (17%) and 20 men (83%). Mean age was 61.7 ± 2.02 years. Gastrointestinal bleeding (33.3%) mesenteric ischemia (20.8%) pancreatitis (20.8%) hepatic dysfunction (16.7%) and cholecystitis (16.7%) were the most common complications. Mortality was 41.7% (10 patients). During the same period mortality in the patients who did not develop gastrointestinal complications was 1.89% (p < 0.0001). Emergency basis reoperation combined operations peripheral vascular disease diabetes mellitus chronic lung disease and impaired left ventricle function were found to be risk factors for the development of postoperative gastrointestinal complications.
Citation Count: 0
Adaptive Sampling Noise Mitigation Technique for Feedback-Based Quantum Algorithms
(Springer international Publishing Ag, 2024) Karabacak, Özkan; Clausen, Henrik Glavind; Karabacak, Ozkan; Wisniewski, Rafal
Inspired by Lyapunov control techniques for quantum systems, feedback-based quantum algorithms have recently been proposed as alternatives to variational quantum algorithms for solving quadratic unconstrained binary optimization problems. These algorithms update the circuit parameters layer-wise through feedback from measuring the qubits in the previous layer to estimate expectations of certain observables. Therefore, the number of samples directly affects the algorithm's performance and may even cause divergence. In this work, we propose an adaptive technique to mitigate the sampling noise by adopting a switching control law in the design of the feedback-based algorithm. The proposed technique can lead to better performance and convergence properties. We show the robustness of our technique against sampling noise through an application for the maximum clique problem.
Citation Count: 1
Analysis of the Patients and Physicians Connection Network on an online Health Information Platform
(IOS Press, 2014) Aydın, Mehmet Nafiz; Perdahci, N. Ziya
Social network applications have gained popularity in the health domain as they bring health information seekers (patients and alike) and medication advice providers (physicians and other relevant actors) together. By employing a network science perspective this research is aimed to understand an information network establishing connections among and between information seekers and providers. We found that such a connection network surfaces most of the essential characteristics of a typical complex network. Furthermore a detailed structural analysis shows some intriguing relations and connection behaviours in the network. Implications of the findings are discussed from the perspectives of medical informatics and social network analysis.
Citation Count: 4
Atomic force microscopy and spectroscopy studies of annealed Ce/Ti/Zr mixed oxide thin films prepared by sol-gel process
(Elsevier Science Bv, 2006) Ghodsi, Farhad E.; Tepehan, Fatma Zehra; Tepehan, Galip Gültekin
Mixed Ce/Ti/Zr oxide thin films with a molar ratio of 0.5:0.25:0.25 were prepared using the sol-gel process and deposited on glass substrates by the dip coating technique. The effect of heat treatment temperature on surface morphology of the films was examined by atomic force microscopy AFM. The optical transmittance and reflectance of the films were measured over the spectral range from 350 to 1000 nm. The refractive index and extinction coefficient and thickness of the films were determined as a function of the heat treatment temperature. The refractive index increased from 1.51 to 2.02 at lambda = 600 nm and the extinction coefficient values increased from 0.006 to 0.094 while the thickness of the films decreased from 81 nm to 45 nm when annealing temperature increased from 100 degrees C to 500 degrees C. The results show that the optical properties and surface morphology of the mixed Cc/Ti/Zr oxide thin films were affected by annealing temperature. (c) 2006 Elsevier B.V. All rights reserved.
Citation Count: 0
Attractiveness Differentially Affects Direct Versus Indirect Face Evaluations in Two Cultures
(Sage Publications Inc, 2023) Cassidy, Brittany S.; Saribay, S. Adil; Yuksel, Huseyin; Kleisner, Karel
Although decades of research have identified facial features relating to people's evaluations of faces, specific features have largely been examined in isolation from each other. Recent work shows that considering the relative importance of these features in face evaluations is important to test theoretical assumptions of impression formation. Here, we examined how two facial features of evolutionary interest, facial attractiveness and facial-width-to-height ratio (FWHR), relate to evaluations of faces across two cultures. Because face evaluations are typically directly measured via self-reports, we also examined whether these features exert differential effects on both direct and indirect face evaluations. Evaluations of standardized photos naturally varying in facial attractiveness and FWHR were collected using the Affect Misattribution Procedure in the United States and Turkey. When their relative contributions were considered in the same model, facial attractiveness, but not FWHR, related to face evaluations across cultures. This positive attractiveness effect was stronger for direct versus indirect evaluations across cultures. These findings highlight the importance of considering the relative contributions of facial features to evaluations across cultures and suggest a culturally invariant role of attractiveness when intentionally evaluating faces.
Citation Count: 13
Bayesian Compressive Sensing For Primary User Detection
(Inst Engineering Technology-IET, 2016) Erküçük, Serhat; Erküçük, Serhat; Cirpan, Hakan Ali
In compressive sensing (CS)-based spectrum sensing literature most studies consider accurate reconstruction of the primary user signal rather than detection of the signal. Furthermore possible absence of the signal is not taken into account while evaluating the spectrum sensing performance. In this study Bayesian CS is studied in detail for primary user detection. In addition to assessing the signal reconstruction performance and comparing it with the conventional basis pursuit approach and the corresponding lower bounds signal detection performance is also considered both analytically and through simulation studies. In the absence of a primary user signal the trade-off between probabilities of detection and false alarm is studied as it is equally important to determine the performance of a CS approach when there is no active primary user. To reduce the computation time and yet achieve a similar detection performance finally the effect of number of iterations is studied for various systems parameters including signal-to-noise-ratio compression ratio mean value of accumulated energy and threshold values. The presented framework in this study is important in the overall implementation of CS-based approaches for primary user detection in practical realisations such as LTE downlink OFDMA as it considers both signal reconstruction and detection.
Citation Count: 1
Bayesian estimation of discrete-time cellular neural network coefficients
(TUBITAK Scientific & Technical Research Council Turkey, 2017) Şenol, Habib; Özmen, Atilla; Şenol, Habib
A new method for finding the network coefficients of a discrete-time cellular neural network (DTCNN) is proposed. This new method uses a probabilistic approach that itself uses Bayesian learning to estimate the network coefficients. A posterior probability density function (PDF) is composed using the likelihood and prior PDFs derived from the system model and prior information respectively. This posterior PDF is used to draw samples with the help of the Metropolis algorithm a special case of the Metropolis--Hastings algorithm where the proposal distribution function is symmetric and resulting samples are then averaged to find the minimum mean square error (MMSE) estimate of the network coefficients. A couple of image processing applications are performed using these estimated parameters and the results are compared with those of some well-known methods.
Citation Count: 3
Beliefs of Living Donors About Recipients' End-Stage Liver Failure and Surgery for Organ Donation
(Elsevier Science Inc, 2017) Krespi-Boothby, Margörit Rita; Tankurt, A.; Acarli, Koray; Kanmaz, Turan; Yankol, Yucel; Kalayoğlu, Murat
Background. The concept of beliefs could provide a basis for how donors may perceive recipients' end-stage liver failure (ESLF) and surgery for organ donation. However there is no such quantitative study. Therefore the objective of this study was to explore beliefs of living donors about recipients' ESLF and surgery for organ donation. Methods. The sample comprised 16 living donors who donated a part of their liver to a patient who had ESLF. The data were analyzed by following established procedures for inductive qualitative analysis. Results. Analysis showed that donors' beliefs can be viewed in a number of groups. Beliefs about recipients' ESLF included diverse explanations for ESLF (blaming oneself and physicians) and physical symptoms (developmental slowing down). Beliefs about being a donor included reasons for being a donor (performing a good deed being healed) barriers to being a donor (other people being ignorant and selfish) ways to manage these barriers (following one's gut feeling) and factors facilitating being a donor (the feeling that one does not have many people to leave behind). Beliefs about surgery for organ donation included physical effects (pain feeling stiff). Beliefs about organ donation included views that general organ donation should be encouraged and that people's awareness should be raised. Conclusions. Existing psychological perspectives could help to interpret some beliefs. Nevertheless other beliefs not previously reported could be considered as targets for individual consultations/psycho-educational programs for fostering emotional well-being.
Citation Count: 0
Bianchi surfaces whose asymptotic lines are geodesic parallels
(Walter De Gruyter Gmbh, 2015) Arsan, Güler Gürpınar; Özdeğer, Abdulkadir
It is proved that every Bianchi surface in E-3 of class C-4 whose asymptotic lines are geodesic parallels is either a helicoid or a surface of revolution.
Citation Count: 4
Bilateral macrostomia as an isolated deformity and its repair with a modified technique
(Springer Verlag, 2002) Peker, Fatih; Açıkel, Cengiz; Karacaoğlu, Ercan; Durak, Nazım
A 3-year-old boy with bilateral congenital macrostomia as an isolated clinical entity is presented. Although this is a rare deformity, it causes functional and cosmetic problems which are difficult to correct. The skin, muscle, and mucosal components of the deformity were separately repaired using a modification of Kaplan's technique.
Citation Count: 1
Broadband matching via reflection function optimization
(Wiley, 2017) Şengül, Metin Y.
In this paper a practical approach is presented for designing broadband matching networks via reflection function optimization. In the proposed algorithm the input or output reflection function of the matching network is expressed in terms of three real polynomials describing the matching network load and generator reflection coefficients. Next one of the polynomials is optimized to get minimum reflection function values in the passband. Then matching network topology and element values are obtained via the formed input reflection coefficient expression. Two examples are presented to explain the usage of the new approach. Copyright (c) 2016 John Wiley & Sons Ltd.
Citation Count: 2
Broadband Matching via Unequal Length Cascaded Transmission Lines
(World Scientific Publ Co Pte Ltd, 2017) Şengül, Metin Y.
In this paper a new approach based on the real frequency technique (RFT) has been proposed to solve broadband matching problems using cascaded unequal length transmission lines. At the end of the design process optimum characteristic impedance and delay values of transmission lines are obtained. Two examples are given to illustrate the utilization of the proposed approach.
Citation Count: 0
Broadband Microwave Amplifier Design with Lumped Elements
(Walter De Gruyter Gmbh, 2016) Şengül, Metin Y.
This study introduces a broadband microwave amplifier design that utilizes the measured scattering parameters of active devices without assuming an initial topology for the matching networks or an analytic form of the system transfer function. The algorithm can be extended to design multistage broadband microwave amplifiers. An example is given to illustrate the application of the proposed method. It was found that the proposed method provides very good initials for CAD tools to further improve amplifier performance by working on the element values.
Citation Count: 29
Cartoon Violence and Freedom of Expression
(Johns Hopkins Univ Press, 2008) Keane, David
The publication of the "Danish cartoons" generated a continuing conflict between freedom of expression and religious tolerance. The article examines the history of cartoon satire, invoking past examples of racial and religious discrimination in cartoons while emphasizing the important role cartoonists have played in criticizing and checking the exercise of power. The legal implications of the "Danish cartoons" is analyzed through the lens of international human rights law, in particular the concepts of hate speech, racial discrimination and religious defamation. Finally the present movement in the UN towards "cartooning for peace" is promoted.

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