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Yayın Yakın alan iletişimi teknolojisi(Türkiye Bilişim Vakfı, 2016-06-24) Özdenizci, Büşra; Ok, Kerem; Aydın, Mehmet Nafiz; Coşkun, VedatYakın Alan İletişimi iki elektronik cihazın kısa mesafede, yüksek frekansta ve düşük bant genişliğinde haberleşmesini sağlayan Radyo Frekansı ile Tanımlama tabanlı bir teknolojidir. NFC uygulamaları temel olarak üç ayrı çalışma kipi kullanırlar ve her bir kipin kullanımının getirmiş olduğu ayrı özellikler ve avantajlar mevcuttur. Her çalışma kipi farklı iş fırsatları ve katma değer olanakları sunabilmektedir. Bu çalışmada, öncelikle dünyada şu an itibari ile mevcut tüm NFC uygulamaları ve prototipleri, kullanmış oldukları çalışma kiplerine göre incelenmiştir. Daha sonra bu çalışmaların her biri ayrıntılı biçimde analiz edilmiş ve oluşturdukları katma değer ortaya konulmuştur. Çalışma, bu alandaki hedef beklentilerimizin konulması ile neticelendirilmiştir.Yayın NFC internal: An indoor navigation system(MDPI AG, 2015-04) Özdenizci Köse, Büşra; Coşkun, Vedat; Ok, KeremIndoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC)-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability.Yayın A tokenization-based communication architecture for HCE-Enabled NFC services(Hindawi Publishing Cor, 2016) Özdenizci Köse, Büşra; Ok, Kerem; Coşkun, VedatFollowing the announcement of Host Card Emulation (HCE) technology, card emulation mode based Near Field Communication (NFC) services have gained further appreciation as an enabler of the Cloud-based Secure Element (SE) concept. A comprehensive and complete architecture with a centralized and feasible business model for diverse HCE-based NFC services will be highly appreciated, particularly by Service Providers and users. To satisfy the need in this new emerging research area, a Tokenization-based communication architecture for HCE-based NFC services is presented in this paper. Our architecture proposes Two-Phased Tokenization to enable the identity management of both user and Service Provider. NFC Smartphone users can store, manage, and make use of their sensitive data on the Cloud for NFC services; Service Providers can also provide diverse card emulation NFC services easily through the proposed architecture. In this paper, we initially present the Two-Phased Tokenization model and then validate the proposed architecture by providing a case study on access control. We further evaluate the usability aspect in terms of an authentication scheme. We then discuss the ecosystem and business model comprised of the proposed architecture and emphasize the contributions to ecosystem actors. Finally, suggestions are provided for data protection in transit and at rest.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 Relocating sensor nodes to maximize cumulative connected coverage in wireless sensor networks(Molecular Diversity Preservation Int, 2008-04) Coşkun, VedatIn order to extend the availability of the wireless sensor network and to extract maximum possible information from the surveillance area, proper usage of the power capacity of the sensor nodes is important. Our work describes a dynamic relocation algorithm called MaxNetLife, which is mainly based on utilizing the remaining power of individual sensor nodes as well as properly relocating sensor nodes so that all sensor nodes can transmit the data they sense to the sink. Hence, the algorithm maximizes total collected information from the surveillance area before the possible death of the sensor network by increasing cumulative connected coverage parameter of the network. A deterministic approach is used to deploy sensor nodes into the sensor field where Hexagonal Grid positioning is used to address and locate each sensor node. Sensor nodes those are not planned to be actively used in the close future in a specific cell are preemptively relocated to the cells those will be in need of additional sensor nodes to improve cumulative connected coverage of the network. MaxNetLife algorithm also includes the details of the relocation activities, which include preemptive migration of the redundant nodes to the cells before any coverage hole occurs because of death of a sensor node. Relocation Model, Data Aggregation Model, and Energy model of the algorithm are studied in detail. MaxNetLife algorithm is proved to be effective, scalable, and applicable through simulations.
