Scopus İndeksli Yayınlar Koleksiyonu
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Article Citation Count: 5A 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. TimurWireless 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.Article Citation Count: 1A 130 nm CMOS Receiver for Visible Light Communication(IEEE-Inst Electrical Electronics Engineers Inc, 2022) Baykaş, Tunçer; Yagan, Muhammed Yaser; Uysal, Murat; Pusane, Ali Emre; Baykas, Tuncer; Dundar, Gunhan; Yalcinkaya, Arda DenizVisible light communication (VLC) is an emerging technology that has been gaining attention over the last few years. Transmission of data at higher rates in a VLC system is mainly limited by the modulation bandwidth of the employed LED. To alleviate this limitation, equalization is frequently employed. This is usually achieved by either using discrete circuit elements or in digital form. In this paper, we present a power-efficient VLC receiver as a system-on-chip, implemented in 130 nm CMOS technology. The proposed receiver supports LEDs with different bandwidths thanks to the switchable equalizer. We tested the proposed receiver using phosphorescent white LEDs with different bandwidths on an experimental VLC link. For each tested LED, around 20 fold improvement in data rate was achieved compared to the original bandwidth of the LED. For the LED with a modulation bandwidth of 1.6 MHz, data rates of 32 Mbps and 50 Mbps at a BER of 10(-2) were obtained at a distance of 2 meters without and with a blue filter, respectively.Book Part Citation Count: 018 - Turkey(Cambridge University Press, 2020) Diner,C.Each of these chapters contains a case study of a couple from the relevant country. Each includes a description of the everyday life of the couple with respect to the division of housework and childcare, a recounting of the history of their relationship and how it became equal, a discussion of how they balance paid work and family, and an analysis of the factors that facilitate their equality. Those factors include their conviction in gender equality, their rejection of essentialist beliefs, their familism, and their socialization in their families of origin. By showing how and why they undo gender, these couples provide lessons on how equality at home can be achieved. © Cambridge University Press 2020Article Citation Count: 0The 1921 Constitution and Beyond: Any Inspiration After 100 Years?(Istanbul University Press, 2022) Arat, Nilay; Topukçu, A.The 1921 Constitution has mostly been considered as a unique piece of legal document in Turkish Legal History with regard to the time it was written, the conditions under it was created, the necessity it touched and the era it changed. The 1921 Constitution had been assessed by scholars, bureaucrats, politicians and lawyers in different times from distinct perspectives. It has got special attention lately as regards to the discussions on constitution-making processes. Even after 100 years, many of its features inspire today's constitutional discussions as the 1921 Constitution touches even today's sociological, political and legal needs. In this context, this paper aims to assess the 1921 Constitution first by pointing out the unique features; then, gives try to answer a question posed whether the 1921 Constitution is a constitution itself, or not. This trial is done under the double constitution period discussions and by pulling out the deficiencies of the 1921 Constitution. Subsequently, the box of inspirational touches of the 1921 Constitution to 100 years beyond is opened. In that sense, it has been found that the understanding of sovereignty that brings it down to its origin “earth/humankind”, the idea of local democracy and the vision on fundamental rights and freedoms that open the door to modern understanding of rights on this part of the world, could be drawn/inherited for today's constitutional making processes. © 2022 Istanbul University Press. All Rights Reserved.Article Citation Count: 1A 2020 vision for the Black Sea region: the Commission on the Black Sea proposes(Routledge Journals Taylor & Francis Ltd, 2010) Aydın, Mustafa; Triantaphyllou, DimitriosThe Black Sea region is coming into its own although it is at times a contested and dangerous neighbourhood. Despite heightened interest in the region its real priorities and needs are still being largely ignored by insiders and outsiders alike. What is needed are regional solutions for regional problems. The authors present the key findings and recommendations of the Commission on the Black Sea a civil society initiative comprising a number of current and former policy-makers scholars and practitioners both from within the region and from outside with the purpose of contributing to a joint vision and a common strategy for the Black Sea region by developing new knowledge in areas of key concern.Article Citation Count: 82D Materials (WS2, MoS2, MoSe2) Enhanced Polyacrylamide Gels for Multifunctional Applications(Mdpi, 2022) Uysal, Bengu Ozugur; Nayir, Seyma; Acba, Melike; Citir, Betul; Durmaz, Sumeyye; Kocoglu, Sevval; Yildiz, EkremMultifunctional polymer composite gels have attracted attention because of their high thermal stability, conductivity, mechanical properties, and fast optical response. To enable the simultaneous incorporation of all these different functions into composite gels, the best doping material alternatives are two-dimensional (2D) materials, especially transition metal dichalcogenides (TMD), which have been used in so many applications recently, such as energy storage units, opto-electronic devices and catalysis. They have the capacity to regulate optical, electronic and mechanical properties of basic molecular hydrogels when incorporated into them. In this study, 2D materials (WS2, MoS2 and MoSe2)-doped polyacrylamide (PAAm) gels were prepared via the free radical crosslinking copolymerization technique at room temperature. The gelation process and amount of the gels were investigated depending on the optical properties and band gap energies. Band gap energies of composite gels containing different amounts of TMD were calculated and found to be in the range of 2.48-2.84 eV, which is the characteristic band gap energy range of promising semiconductors. Our results revealed that the microgel growth mechanism and gel point of PAAm composite incorporated with 2D materials can be significantly tailored by the amount of 2D materials. Furthermore, tunable band gap energies of these composite gels are crucial for many applications such as biosensors, cartilage repair, drug delivery, tissue regeneration, wound dressing. Therefore, our study will contribute to the understanding of the correlation between the optical and electronic properties of such composite gels and will help to increase the usage areas so as to obtain multifunctional composite gels.Note Citation Count: 02nd tourism and hospitality networking conference | RESNET’22(Routledge, 2023) Serra, J.[No abstract available]Article Citation Count: 5(3+3+2) warped-like product manifolds with Spin(7) holonomy(Elsevier Science Bv, 2011) Bilge, Ayşe Hümeyra; Bilge, Ayşe HümeyraWe consider a generalization of eight-dimensional multiply warped product manifolds as a special warped product by allowing the fiber metric to be non-block diagonal. We define this special warped product as a (3 + 3 + 2) warped-like manifold of the form M = F x B. where the base B is a two-dimensional Riemannian manifold and the fibre F is of the form F = F-1 x F-2 where the F-i(i = 1 2) are Riemannian 3-manifolds. We prove that the connection on M is completely determined by the requirement that the Bonan 4-form given in the work of Yasui and Ootsuka [Y. Yasui and T. Ootsuka Spin(7) holonomy manifold and superconnection Class. Quantum Gravity 18(2001)807-816] be closed. Assuming that the F-i are complete connected and simply connected it follows that they are isometric to S-3 with constant curvature k > 0 and the Yasui-Ootsuka solution is unique in the class of (3 + 3 + 2) warped-like product metrics admitting a specific Spin(7) structure. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.Article Citation Count: 43D indoor positioning with spatial modulation for visible light communications(Elsevier, 2023) Arsan, Taner; Yesilirmak, Yalin Evrim; Bayman, Irem Ozgur; Arsan, Taner; Panayırcı, Erdal; Stevens, NobbyIn this paper, a novel three-dimensional (3D) indoor visible light positioning (VLP) algorithm is proposed based on the spatial modulation (SM) and its error performance assessed as compared to the conventional received signal strength (RSS)-based 3D VLP systems. As contrasted to the traditional VLP system, the proposed SM-based 3D VLP system first estimates the optical channel gain between the transmitting light-emitting diodes (LEDs) and the two photo detectors (PDs) attached to the user by a pilot-based channel estimation technique. Then, unknown 3D positions of the receiver are determined by the trilateration algorithm with distances computed from the estimates of the channel gains. Consequently, the 3D VLP system achieves an interference -free transmission with increased spectral efficiency and without the need for a demultiplexing process at the receiving end. The algorithm's performance is evaluated regarding positioning error by applying the SM over four LEDs and the number of pilots selected as a function of the environmental signal-to-noise ratios (SNRs). The computer simulation results show that the positioning errors are obtained in an order of magnitude smaller than RSS-based techniques in an indoor industrial environment. This is mainly because the distances involved in determining the 3D positions can be determined more precisely by the pilot-aided channel estimation method without creating any data rate problem in transmission due to the higher spectral efficiency of the SM.Article Citation Count: 23D Printer Selection for the Sustainable Manufacturing Industry Using an Integrated Decision-Making Model Based on Dombi Operators in the Fermatean Fuzzy Environment(Mdpi, 2024) Görçün, Ömer Faruk; Zolfani, Sarfaraz Hashemkhani; Kucukonder, Hande; Antucheviciene, Jurgita; Pavlovskis, MiroslavasThree-dimensional printers (3DPs), as critical parts of additive manufacturing (AM), are state-of-the-art technologies that can help practitioners with digital transformation in production processes. Three-dimensional printer performance mostly depends on good integration with artificial intelligence (AI) to outperform humans in overcoming complex tasks using 3DPs equipped with AI technology, particularly in producing an object with no smooth surface and a standard geometric shape. Hence, 3DPs also provide an opportunity to improve engineering applications in manufacturing processes. As a result, AM can create more sustainable production systems, protect the environment, and reduce external costs arising from industries' production activities. Nonetheless, practitioners do not have sufficient willingness since this kind of transformation in production processes is a crucial and irrevocable decision requiring vast knowledge and experience. Thus, presenting a methodological frame and a roadmap may help decision-makers take more responsibility for accelerating the digital transformation of production processes. The current study aims to fill the literature's critical theoretical and managerial gaps. Therefore, it suggests a powerful and efficient decision model for solving 3DP selection problems for industries. The suggested hybrid FF model combines the Fermatean Fuzzy Stepwise Weight Assessment Ratio Analysis (FF-SWARA) and the Fermatean Ranking of Alternatives through Functional mapping of criterion sub-intervals into a Single Interval (FF-RAFSI) approaches. The novel FF framework is employed to solve a critical problem encountered in the automobile manufacturing industry with the help of two related case studies. In addition, the criteria are identified and categorized regarding their influence degrees using a group decision approach based on an extended form of the Delphi with the aid of the Fermatean fuzzy sets. According to the conclusions of the analysis, the criteria "Accuracy" and "Quality" are the most effective measures. Also, the suggested hybrid model and its outcomes were tested by executing robustness and validation checks. The results of the analyses prove that the suggested integrated framework is a robust and practical decision-making tool.Article Citation Count: 23D 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, OnderPolyacrylamide (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.Article Citation Count: 13D-printed actuator-based beam-steering approach for improved physical layer security in visible light communication(Optica Publishing Group, 2022) Erdem, Mehmet Can; Gurcuoglu, Oguz; Panayırcı, Erdal; Kurt, Gunes Karabulut; Ferhanoglu, OnurIn this study, we present the design, manufacture, and implementation of a 3D-printed lens scanner-based beam steering for use in visible light communication (VLC) applications. The 5 cm x 5 cm scanner is designed for low-cost 3D printing with fused deposition modeling using polylactic acid. Scanning is facilitated through electromagnetic actuation of the lens frame, carrying a conventional 25 mm lens, from two nearly orthogonal directions. The serpentine spring that connects the lens frame to the external frame is tailored to offer similar spring constants in the directions of actuation and has minimal (<1.5 mm) sag due to the mass of the lens. The manufactured actuator was integrated on a miniaturized VLC test bed (70 cm x 40 cm x 40 cm). Using the test bed, we characterized the applied voltage versus beam displacement behavior of the actuator in the lateral plane and demonstrated beam steering on amoving target with face-recognition feedback. The proposed scheme was targeted to offer an improved security measure in VLC through tracking the legitimate receiver (i.e., via face recognition) and uses the feedback to steer the focused light onto the targeted device. The joint use of focusing and steering features allows for the legitimate receiver to roam within the room while enjoying the improved secrecy due to the focused light. We calculate the secrecy capacity for the demonstrated approach, which compares favorably with a number of jamming, spatial modulation, and beam-forming counterparts. The presented actuator can be used with larger room dimensions, yet upscaling to larger illumination units will require the use of a lens having smaller focus to address a larger total steering angle. (C) 2022 Optica Publishing GroupArticle Citation Count: 3Abortion services at hospitals in Istanbul(Taylor & Francis Ltd, 2017) O'Neil, Mary LouObjective: Despite the existence of a liberal law on abortion in Turkey there is growing evidence that actually securing an abortion in Istanbul may prove difficult. This study aimed to determine whether or not state hospitals and private hospitals that accept state health insurance in Istanbul are providing abortion services and for what indications. Method: Between October and December 2015 a mystery patient telephone survey of 154 hospitals 43 public and 111 private in Istanbul was conducted. Results: 14% of the state hospitals in Istanbul perform abortions without restriction as to reason provided in the current law while 60% provide the service if there is a medical necessity. A quarter of state hospitals in Istanbul do not provide abortion services at all. 48.6% of private hospitals that accept the state health insurance also provide for abortion without restriction while 10% do not provide abortion services under any circumstances. Key conclusions: State and private hospitals in Istanbul are not providing abortion services to the full extent allowed under the law. The low numbers of state hospitals offering abortions without restriction indicates a de facto privatization of the service. This same trend is also visible in many private hospitals partnering with the state that do not provide abortion care. While many women may choose a private provider the lack of provision of abortion care at state hospitals and those private hospitals working with the state leaves women little option but to purchase these services from private providers at some times subtantial costs.Article Citation Count: 18Absolute configuration and biological profile of pyrazoline enantiomers as MAO inhibitory activity(Wiley, 2019) Yelekçi, Kemal; Sarıgül, Sevgi; Bultinck, Patrick; Herrebout, Wouter; Doğan, İlknur; Yelekçi, Kemal; Uçar, Gülberk; Kelekçi, Nesrin GökhanA new racemic pyrazoline derivative was synthesized and resolved to its enantiomers using analytic and semipreparative high-pressure liquid chromatography. The absolute configuration of both fractions was established using vibrational circular dichroism. The in vitro monoamine oxidase (MAO) inhibitory profiles were evaluated for the racemate and both enantiomers separately for the two isoforms of the enzyme. The racemic compound and both enantiomers were found to inhibit hMAO-A selectively and competitively. In particular the R enantiomer was detected as an exceptionally potent and a selective MAO-A inhibitor (K-i = 0.85 x 10(-3) +/- 0.05 x 10(-3) mu M and SI: 2.35 x 10(-5)) whereas S was determined as poorer compound than R in terms of K-i and SI (0.184 +/- 0.007 and 0.001). The selectivity of the enantiomers was explained by molecular modeling docking studies based on the PDB enzymatic models of MAO isoforms.Book Part Citation Count: 0Book Part Citation Count: 0Accelerated trends in tourism marketing and tourist behaviour(Taylor and Francis, 2023) Kozak, MetinDespite its much longer historical background, particularly since the 1980s, the world of marketing has entered a new era, becoming more consumer-oriented. Thus, consumers have come to be at the centre of all production and marketing activities in the business world. In the first wave, commencing from the early 2000s, mass consumption has gained more emphasis with technology development. The tourism and hospitality industry have also been directly affected by such developments, and we have seen new ways of marketing methods and new types of tourism activities/products. As a second wave, one more feature of the 21st century is that it has mainly been dominated by either regional or global incidents such as terrorism and pandemic. Together with disseminating the latest pandemic worldwide, marketing methods and consumer behaviour have undergone another dramatic transformation once again. Its initial outcomes have been in practice now, e.g. more individualised lifestyles, more personalised marketing and consumerism, more concerns with regard to safety and security, greater awareness of fashion, and more engagement on social media. Consequently, this chapter aims to examine the new trends that are likely to be encountered in tourism marketing based on the possible changes in consumer behaviour in the light of the developments of the last two decades and two waves. © 2024 selection and editorial matter, Alastair M. Morrison and Dimitrios Buhalis.Conference Object Citation Count: 1Accelerating Brain Simulations on Graphical Processing Units(IEEE, 2015) Bozkuş, Zeki; El-Ghazawi, Tarek A.; Bozkuş, ZekiNEural Simulation Tool(NEST) is a large scale spiking neuronal network simulator of the brain. In this work we present a CUDA(R) implementation of NEST. We were able to gain a speedup of factor 20 for the computational parts of NEST execution using a different data structure than NEST's default. Our partial implementation shows the potential gains and limitations of such possible port. We discuss possible novel approaches to be able to adapt generic spiking neural network simulators such as NEST to run on commodity or high-end GPGPUs.Article Citation Count: 2Accented Essays: Documentary as Artistic Practice in Contemporary Audiovisual Works from Turkey(Routledge, 2019) Akçalı, ElifThis 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.Article Citation Count: 0Acceptable 'expats' versus unwanted 'Arabs': Tracing hierarchies through everyday urban practices of skilled migrant women in Istanbul(Wiley, 2024) Tuncer, EzgiThis article focuses on ethnic hierarchies found within highly educated migrant women working in Istanbul traced through their everyday urban practices. It introduces the stratified and comparative results of migration and resettlement of those from the Global North and the Global South through a comprehensive analysis on their urban lives, including their social positionings, preferences of neighbourhoods and daily patterns of their use of the city. Contrary to the common conception that skilled migrants are privileged, our research reveals inequalities and discriminatory practices they face that intersect with gender, nationality and ethnicity. Our research, based on qualitative analyses of in-depth interviews along with online subjective mapping representing use of the city, also reveals that regardless of their origin and identity, almost all our participants experience verbal/physical sexual harassment or discrimination in public space in Istanbul, which forces women to produce spatial tactics of everyday life.Article Citation Count: 16Accretion flows in nonmagnetic white dwarf binaries as observed in X-rays By:Balman, S (Balman, Solen)[ 1 ](Elsevıer Scı Ltd, 2020) Balman, ŞölenCataclysmic Variables (CVs) are compact binaries with white dwarf (WD) primaries. CVs and other accreting WD binaries (AWBs) are useful laboratories for studying accretion flows, gas dynamics, outflows, transient outbursts, and explosive nuclear burning under different astrophysical plasma conditions. They have been studied over decades and are important for population studies of galactic X-ray sources. Recent space-and ground-based high resolution spectral and timing studies, along with recent surveys indicate that we still have observational and theoretical complexities yet to answer. I review accretion in nonmagnetic AWBs in the light of X-ray observations. I present X-ray diagnostics of accretion in dwarf novae and the disk outbursts, the nova-like systems, and the state of the research on the disk winds and outflows in the nonmagnetic CVs together with comparisons and relations to classical and recurrent nova systems, AM CVns and Symbiotic systems. I discuss how the advective hot accretion flows (ADAF-like) in the inner regions of accretion disks (merged with boundary layer zones) in nonmagnetic CVs explain most of the discrepancies and complexities that have been encountered in the X-ray observations. I stress how flickering variability studies from optical to X-rays can be probes to determine accretion history and disk structure together with how the temporal and spectral variability of CVs are related to that of LMXBs and AGNs. Finally, I discuss the nature of accretion in nonmagnetic WDs in terms of ADAF-like accretion flows, and elaborate on the solu-tions it brings and its complications, constructing an observational framework to motivate new theoretical calculations that introduce this flow-type in disks, outflow and wind models together with disk-instability models of outbursts and nova outbursts in AWBs and WD physics, in general. (C) 2020 COSPAR. Published by Elsevier Ltd. All rights reserved. Keywords
