WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Conference Object A Novel Signaling Pathway That Governs Tumor Metastasis: Ceramide Regulates Direct Crosstalk Between TGF-Β and Sonic Hedgehog Signaling(Federation of American Society for Experimental Biology, 2016) Gencer, Salih; Ogretmen, BesimConference Object Ceramide Is a Key Factor That Regulates the Crosstalk Between TGF-Β and Sonic Hedgehog Signaling at the Basal Cilia to Control Cell Migration and Tumor Metastasis(Federation Amer Soc Exp Biol, 2016-07) Gencer, Salih; Oleinik, Natalia; Dany, Mohammed; Ogretmen, BesimConference Object Citation - WoS: 49Citation - Scopus: 54You May Not Reap What You Sow: How Employees' Moral Awareness Minimizes Ethical Leadership's Positive Impact on Workplace Deviance(Springer, 2017-08-02) Gok, Kubilay; Sumanth, John J.; Bommer, William H.; Demirtas, Ozgur; Arslan, Aykut; Eberhard, Jared; Yigit, AhmetAlthough a growing body of research has shown the positive impact of ethical leadership on workplace deviance, questions remain as to whether its benefits are consistent across all situations. In this investigation, we explore an important boundary condition of ethical leadership by exploring how employees' moral awareness may lessen the need for ethical leadership. Drawing on substitutes for leadership theory, we suggest that when individuals already possess a heightened level of moral awareness, ethical leadership's role in reducing deviant actions may be reduced. However, when individuals lack this strong moral disposition, ethical leadership may be instrumental in inspiring them to reduce their deviant actions. To enhance the external validity and generalizability of our findings, the current research used two large field samples of working professionals in both Turkey and the USA. Results suggest that ethical leadership's positive influence on workplace deviance is dependent upon the individual's moral awareness-helpful for those employees whose moral awareness is low, but not high. Thus, our investigation helps to build theory around the contingencies of ethical leadership and the specific audience for whom it may be more (or less) influential.Article Citation - WoS: 11Citation - Scopus: 13Wireless Sensor Network-Based Communication for Cooperative Simultaneous Localization and Mapping(Pergamon-Elsevier Science Ltd, 2015-01) Tuna, Gurkan; Gungor, Vehbi Cagri; Potirakis, Stelios M.; Zeadally, SheraliThis paper presents a novel approach of using a Wireless Sensor Network (WSN) as the communication means for Multi-Robot, Cooperative, Simultaneous Localization and Mapping (CSLAM) applications investigating the associated design challenges and suggesting corresponding solutions. Although the proposed approach brings several benefits including an increased coverage and communication range, self-organization capabilities, quick deployment, and flexible architecture, the realization is interrelated with performance in terms of energy efficiency and reliability. In this respect, the applicability of the WSNs for the presented approach is investigated. Centralized and distributed map merging methods in WSN-based CSLAM are evaluated in detail and the impacts of packet delays and losses on the performance of CSLAM algorithms are shown. Additionally, the involved network congestion and contention dynamics are presented, while the effects of observation range, speed, time intervals between observations, and odometry readings on the SLAM accuracy are shown based on an extensive set of simulation studies. (C) 2014 Elsevier Ltd. All rights reserved.Article Citation - WoS: 19Citation - Scopus: 21Wireless Sensing in Complex Electromagnetic Media: Construction Materials and Structural Monitoring(IEEE-Inst Electrical Electronics Engineers Inc, 2015-10) Ozbey, Burak; Demir, Hilmi Volkan; Kurc, Ozgur; Erturk, Vakur B.; Altintas, AyhanIn this paper, wireless sensing in the presence of complex electromagnetic media created by combinations of reinforcing bars and concrete is investigated. The wireless displacement sensing system, primarily designed for use in structural health monitoring (SHM), is composed of a comb-like nested split-ring resonator (NSRR) probe and a transceiver antenna. Although each complex medium scenario is predicted to have a detrimental effect on sensing in principle, it is demonstrated that the proposed sensor geometry is able to operate fairly well in all scenarios except one. In these scenarios that mimic real-life SHM, it is shown that this sensor exhibits a high displacement resolution of 1 mu m, a good sensitivity of 7 MHz/mm in average, and a high dynamic range extending over 20 mm. For the most disruptive scenario of placing concrete immediately behind NSRR, a solution based on employing a separator behind the probe is proposed to overcome the handicaps introduced by the medium. In order to obtain a one-to-one mapping from the measured frequency shift to the displacement, a numerical fit is proposed and used. The effects of several complex medium scenarios on this fit are discussed. These results indicate that the proposed sensing scheme works well in real-life SHM applications.Article Citation - WoS: 1When the Railway Reached Istanbul: The Making of Sirkeci Terminus, 1870-1888(Routledge Journals, Taylor & Francis Ltd, 2017-07-16) Tozoglu, AhmetSince its establishment as a capital city, the historical topography of Istanbul has witnessed significant changes, created not only by devastating earthquakes and fires, but also by the implementation of large-scale imperial projects. In the existing literature, the transformation of Istanbul's urban area in the nineteenth century has largely explored the topics of new urban regulations, institutions and their implication after the Tanzimat (reform) decree of 1839. This article aims to explore a lesser-known dimension of nineteenth-century developments of the city: the extension of the railway into the heart of Istanbul's historical peninsula, and the spatial change around the Sirkeci district due to the physical expansion of the terminus area. The construction of a larger terminus (inaugurated in 1890) is relatively well documented in architectural history, yet developments prior to this monumental construction have been less explored so far. Thus, this article also aims to investigate the project's development and implementation phases in the second half of the nineteenth century, when the city witnessed continuous urban reformation processes by focusing on the intertwined relations of different agents in the urban space.Article Citation - WoS: 4Citation - Scopus: 4Very Low Density Amorphous Phase of Zircon(Elsevier Science Bv, 2019-06) Bolat, Suleyman; Durandurdu, MuratUsing a reliable ab initio molecular dynamics method, we investigate the rapid solidification of the zircon melt. Accompanied by amorphization, a drastic volume expansion of 27% is perceived. This value is fairly larger than 18% observed in the metamict zircon. Such a large volume swelling leads to a significant decrease in the mean coordination number of Zr atoms, which is about 5.66 and the lowest one reported so far. On the other hand, the volume expansion is found to have almost no impact on the average coordination number of Si atoms i.e., they maintain their tetragonal coordination. As suggested by earlier investigations, the polymerization of SiO4 units is witnessed but our model shows the highest polymerization with respect to the previous simulations. Based on our findings, we propose that our model does not represent the metamict zircon but a very low density amorphous phase of zircon.Article Citation - WoS: 3Citation - Scopus: 5Validation of Higher-Order Approximations and Boundary Conditions for Lossy Conducting Bodies(IEEE-Inst Electrical Electronics Engineers Inc, 2014-09) Sukharevsky, Ilya O.; Altintas, AyhanThe problem of high-frequency diffraction by a smooth lossy body with high conductivity is considered. In addition to the geometrical optics approximation, additional asymptotic terms are derived to take into account the curvature of the boundary and material properties. Since these higher-order terms are derived by taking into account exact boundary conditions, it is easy to learn about the limitations of impedance conditions and to determine more accurate approximate conditions. The obtained higher-order boundary conditions and their limitations are numerically validated by solving Muller's second-kind integral equations.Article Citation - WoS: 6Citation - Scopus: 6Uncovering Nanoclusters in Amorphous AlN: An Ab Initio Study(Wiley, 2014-12-22) Durandurdu, MuratAmorphous AlN (a-AlN) is modeled by melt-and-quench technique using ab initio molecular dynamic simulations. For the first time, three-dimensional hexagonal-like nanoclusters embedded in amorphous matrix are proposed for a-AlN. The model is chemically ordered and dominantly fourfold coordinated, but its short-range order is partially different from the crystalline morphology due to the nanoclusters. The model is semiconducting with a theoretical band gap of 1.7eV.Article Citation - WoS: 54Citation - Scopus: 57Ultralow Bandgap Molecular Semiconductors for Ambient-Stable and Solution-Processable Ambipolar Organic Field-Effect Transistors and Inverters(Royal Soc Chemistry, 2017) Ozdemir, Resul; Choi, Donghee; Ozdemir, Mehmet; Kwon, Guhyun; Kim, Hyekyoung; Sen, Unal; Usta, HakanThe design and development of novel ambipolar semiconductors is very crucial to advance various optoelectronic technologies including organic complementary (CMOS) integrated circuits. Although numerous high-performance ambipolar polymers have been realized to date, small molecules have been unable to provide high ambipolar performance in combination with ambient-stability and solution-processibility. In this study, by implementing highly p-electron deficient, ladder-type IFDK/IFDM acceptor cores with bithiophene donor units in D-A-D pi-architectures, two novel small molecules, 2OD-TTIFDK and 2OD-TTIFDM, were designed, synthesized and characterized in order to achieve ultralow band-gap (1.21-1.65 eV) semiconductors with sufficiently balanced molecular energetics for ambipolarity. The HOMO/LUMO energies of the new semiconductors are found to be -5.47/-3.61 and -5.49/-4.23 eV, respectively. Bottom-gate/top-contact OFETs fabricated via solution-shearing of 2OD-TTIFDM yield perfectly ambient stable ambipolar devices with reasonably balanced electron and hole mobilities of 0.13 cm(2) V-1 s(-1) and 0.01 cm(2) V-1 s(-1), respectively with I-on/I-off ratios of similar to 10(3)-10(4), and 2OD-TTIFDK-based OFETs exhibit ambipolarity under vacuum with highly balanced (mu(e)/mu(h) similar to 2) electron and hole mobilities of 0.02 cm(2) V-1 s(-1) and 0.01 cm(2) V-1 s(-1), respectively with I-on/I-off ratios of similar to 10(5)-10(6). Furthermore, complementary-like inverter circuits were demonstrated with the current ambipolar semiconductors resulting in high voltage gains of up to 80. Our findings clearly indicate that ambient-stability of ambipolar semiconductors is a function of molecular orbital energetics without being directly related to a bulk p-backbone structure. To the best of our knowledge, considering the processing, charge-transport and inverter characteristics, the current semiconductors stand out among the best performing ambipolar small molecules in the OFET and CMOS-like circuit literature. Our results provide an efficient approach in designing ultralow band-gap ambipolar small molecules with good solution-processibility and ambient-stability for various optoelectronic technologies, including CMOS-like integrated circuits.