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Yayın Optimal deployment in randomly deployed heterogeneous WSNs: A connected coverage approach(Academic Press Ltd- Elsevier Science Ltd, 2014-11) Sevgi, Cüneyt; Koçyiğit, AltanWireless sensor networks (WSNs) are resource-scarce networks and the optimization of the resources is challenging. As far as random deployment is concerned, the optimization of these resources becomes even more difficult In this paper, a novel framework is proposed for solving optimal deployment problems for randomly deployed and clustered WSNs. In several existing approaches to solve these problems, either only partial-coverage is considered or only connectivity is analyzed when full-coverage is assured. Through this study, we aim to contribute to the better understanding of partial connected coverage. For this purpose, we introduce cluster size formulations which provide network designers with estimating partial-coverage easily. While the proposed framework facilitates our cluster size formulations for coverage estimations, it also adopts the percolation theory to analyze the degree of connectivity when the targeted degree of partial-coverage is achieved. As the partial connected coverage approach reflects real-life deployment scenarios, the use of percolation theory results in generic solutions of optimal deployment problems, which indeed makes the solution independent from any routing algorithms. Moreover, a practical optimal deployment problem is formulated to find the cheapest WSN application that satisfies the targeted degree of partial connected coverage. Further, in this paper, the cost effectiveness of the node heterogeneity is investigated through comparing the heterogeneous WSNs with their homogeneous counterparts.Yayın The correlation of fast OSL component with the TL peak at 325 degrees C in quartz of various origins(Elsevier Science BV, 2010-02) Kitis, George; Güneç Kıyak, Nafiye; Polymeris, George S.; Tsirliganis, Nestor C.The fast component of the optically stimulated luminescence (OSL) signal in quartz is the basic tool for the optical dating. Its relation with the thermoluminescence (TL) glow-peak at about 325 degrees C is well established for naturally irradiated quartz. This relationship is also an important part of a general model for quartz on which many theoretical simulations of various OSL experimental results have been based. In the present work this relationship is systematically investigated in nine quartz samples of different origin. The linearly modulated OSL (LM-OSL) curves of all quartz samples for stimulation time less than 50s consists of two components discriminated easily by a computerized curve deconvolution (CCD) analysis. By comparing the un-bleached to the respective bleached TL glow-curve, it is found that the system of these two fast OSL components is directly related with only a small portion of the electron traps responsible for the TL glow-peaks in the temperature region 200-400 degrees C. By increasing the stimulation times, besides the two fast components, the medium and the slow components are also obtained. The medium and slow components are clearly related with the main body of the electron traps responsible for TL glow-peaks in the same temperature region 200-400 degrees C. Despite their different origin all quartz samples show an appreciable homogeneity concerning the number and time position of the individual components, whereas, the relative TL/OSL intensities vary strongly from sample to sample with the integrated TL intensity being generally much less than the integrated OSL intensity.Yayın New quartz technique for OSL dating of limestones(2010) Liritzis, Ioannis; Drivaliari, N.; Polymeris, George S.; Katagas, Christos G.The equivalent dose De determination of limestone-made ancient constructions by thermoluminescence (TL) prevents accurate measurements and requires plateau test of bleached curves. Optical stimulated luminescence (OSL) of quartz and feldspar minerals for surface dating is routinely applied for De but not for limestones. Here the OSL of present traces of such minerals removed with powder from surface limestone bleached by sunlight overcomes this issue and offers an alternative way for De. This is verified with further test examples.Yayın The survey on Near Field Communication(MDPI, 2015-06) Coşkun, Vedat; Özdenizci Köse, Büşra; Ok, KeremNear Field Communication (NFC) is an emerging short-range wireless communication technology that offers great and varied promise in services such as payment, ticketing, gaming, crowd sourcing, voting, navigation, and many others. NFC technology enables the integration of services from a wide range of applications into one single smartphone. NFC technology has emerged recently, and consequently not much academic data are available yet, although the number of academic research studies carried out in the past two years has already surpassed the total number of the prior works combined. This paper presents the concept of NFC technology in a holistic approach from different perspectives, including hardware improvement and optimization, communication essentials and standards, applications, secure elements, privacy and security, usability analysis, and ecosystem and business issues. Further research opportunities in terms of the academic and business points of view are also explored and discussed at the end of each section. This comprehensive survey will be a valuable guide for researchers and academicians, as well as for business in the NFC technology and ecosystem.Yayın Investigation of the OSL signal from very deep traps in natural quartz(Univ Agean, Dept Mediterranean Stud, 2010) Kitis, George; Güneç Kıyak, Nafiye; Polymeris, George S.; Pagonis, VasilisIt has been recently reported by several studies that a thermally transferred optically stimulated luminescence (TT-OSL) signal from quartz grains can be used to extend the dating range for quartz samples. The TT-OSL signals are believed to consist of a recuperated OSL (ReOSL) component and a basic-transferred OSL (BT-OSL) component. In the present work the TT-OSL signals from several types of unfired quartz samples were studied. A special protocol was used, which allowed the measure the OSL from very deep traps (VDT) as a function of the OSL stimulation temperature. It was found that all quartz samples exhibit TT-OSL signals, which are depended on sample and on the OSL stimulation temperature. The activation energy of the process was evaluated and the influences of the TT-OSL on the ReOSL dating protocol are discussed.
