Cilt:61 Sayı:01 (2019)

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https://dspace.ankara.edu.tr/handle/20.500.12575/76507

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Browsing Cilt:61 Sayı:01 (2019) by Author "Mühendislik Fakültesi"

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    Desıgning a Secure Blockchain-Based Trading Platform for Internet of Things
    (Ankara Üniversitesi Fen Fakültesi, 2019-06-30) Osmanoğlu, Murat; Elbuz, Aydın; Tanrıöver, Ömer Özgür; Bilgisayar Mühendisliği; Mühendislik Fakültesi
    Blockchain, a distributed database technology attracts intensive attention recently. It was first described in 1991 by Stuart Haber and W. Scott Stornetta, in order to prevent tampering for document timestamps. After that, Satoshi Nakamoto conceptualized this technology with his work, a peer-to-peer electronic cash system named as Bitcoin. Due to its authenticity, user anonymity and data immutability; this technology has also been applied to different areas ranging from finance, supply-chain managements to social services. In this paper, we propose a blockchain based application for trading data, collected from IoT devices. Our application enables the sellers to commercialize their data in exchange of the currency produced by the application. The application also utilizes smart contracts to establish trust between both sides of the exchange. Furthermore, we discuss the security and reliability of the system components
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    Estimating co2 Emissions By Using Energy Intensıty Data of Oecd Countries
    (Ankara Üniversitesi Fen Fakültesi, 2019-06-30) Gunduç, Semra; Eryiğit, Recep; Bilgisayar Mühendisliği; Mühendislik Fakültesi
    It is discussed that economic development has an essential effect on the country’s CO2 emission which plays an important role in global warming. In this research well-known machine learning algorithm Extreme Learning Machine, ELM, is used to investigate the relationship between CO2 emission and energy intensity for countries in OECD. The results indicate a strong correlation and the method perform well for estimation.
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    Focusing, Imaging and Fourier Transforming With a Large Numerical Aperture, Dielectric Flat Photonic Crystal Lens in Metamaterial Regime
    (Ankara Üniversitesi Fen Fakültesi, 2019-06-30) Çolak, Evrim; Çakmak, Atilla Özgür; Elektrik-Elektronik Mühendisliği; Mühendislik Fakültesi
    An untraditional Gradient Index Photonic Crystal (GRIN PC) is employed within the long wavelength regime to exhibit focusing, imaging and Fourier Transforming. A very large numerical aperture is aimed by breaking the paraxial wave approximation and the slowly changing refractive index assumption. This untraditional GRIN PC is shown to exhibit very similar lensing characteristics as its analytically solvable counterparts demonstrate. The results suggest that Fourier Transforming together with Fractional Fourier Transforms can be obtained from the present design. The performance of the GRIN PC lens is very much dependent on the excitation source as it is expected from GRIN optics and adiffractional propagating beams over large distances can be obtained.
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    Prıvacy-Preservıng K-Nearest Neıghbour Interpolatıon Method ın an Outsourced Envıronment
    (Ankara Üniversitesi Mühendislik Fakültesi, 2019-06-30) KALIDEEN, Muhammad Rifthy; Osmanoğlu, Murat; Tuğrul, Bülent; Bilgisayar Mühendisliği; Mühendislik Fakültesi
    One of the most emerging computer technologies of this decade is cloud computing that allows data owners to outsource their storage and computing requirements. It enables data owners to avoid the costs of building and maintaining a private storage infrastructure. While outsourcing data to cloud promises significant benefits, it possesses substantial security and privacy concerns, especially when data stored in the cloud is sensitive and confidential, like a business plan. Encrypting the data before outsourcing can ensure privacy. However, it will be very difficult to process the cipher text created by the traditional encryption method. Considering this fact, we propose an efficient protocol that allows a query owner to retrieve the interpolation of the top k records from two different databases that are closest to a query point. Note that the databases are stored in two different cloud service providers in encrypted form. We also show that the proposed protocol ensures the privacy and the security of the data and the query point.