Arama Sonuçları

Listeleniyor 1 - 10 / 71
  • Yayın
    Realities & constraints of coal from energy and environmental perspectives
    (University of Pittsburgh, 2010) Ekinci, Ekrem
    [No abstract available]
  • Yayın
    The sectoral sweeper scheme for wireless sensor networks: Adaptive antenna array based sensor node management and location estimation
    (Kluwer Academic Publishers-Plenum Publishers, 2006-12) Erdoğan, Ayhan; Coşkun, Vedat; Kavak, Adnan
    We introduce a novel sensor node management and location estimation method referred as sectoral sweeper (SS) scheme that uses an adaptive antenna array (AAA) at a central node in wireless sensor networks (WSNs). With the SS scheme, the central node can activate or deactivate the nodes in a desired region which is specified by beam direction and beam width of the transmit beam and also by minimum and maximum thresholds (R (min) and R (max)) for the received signal strength indicator (RSSI) of signals received by the nodes. In order to perform a specified task that is associated with a Task_id, two different beams are transmitted, which are task region beam and routing region beam to switch the nodes into active or routing modes. Since our scheme does not require any additional software or hardware for node management and location estimation in sensor nodes, the deficiencies of tiny sensors are effectively eliminated. The proposed scheme is shown to reduce the number of sensing nodes and the amount of data traffic in the network, thus leading to considerable savings in energy consumption and prolonged sensor lifetime.
  • Yayın
    Primitives of service oriented information system development
    (2011) Aydın, Mehmet Nafiz; Yalçınkaya, Tayfun
    One can find the long standing problems with conceptual modeling such as model transformation, reusability and agility in the classical information system development (ISD). New approaches may help in overcoming these issues in conventional ISD's problems. The service oriented approach which is one of the promising approaches, brings solutions to some existing problems. By adopting service orientation in ISD - which we call service oriented ISD, one can deal with the aforementioned problems. This study examines the very notion of service in the context of conceptual modeling method. In particular, we show how to support service modeling in terms of guidance (that is, the way of modeling). The proposed modeling support is demarcated along with a method at the foundational level. The paper is a conceptual and work-in-progress paper.
  • Yayın
    Comments on "upper cutoff frequency of the bound wave and new leaky wave on the slotline"
    (IEEE-INST Electrical Electronics Engineers Inc, 1999-05) İdemen, Mehmet Mithat; Büyükaksoy, İbrahim Alinur
    [No abstract available]
  • Yayın
    Deterministic local doubling of W states
    (OSA - The Optical Society, 2016-11-01) Yeşilyurt, Can; Buğu, Sinan; Özaydın, Fatih; Altıntaş, Azmi Ali; Tame, Mark S.; Yang, Lan; Özdemir, Şahin Kaya
    In large quantum systems, multipartite entanglement can be found in many inequivalent classes. Preparing states of arbitrary size in different classes is important for performing a wide range of quantum protocols. W states, in particular, constitute a class with a variety of quantum networking protocols. However, all known schemes for preparing polarization encoded photonic W states are probabilistic, with resource requirements increasing at least sub-exponentially. We propose a deterministic scheme for preparing W states of size of any power of 2, which requires no prior entanglement and can be performed locally. We introduce an all-optical setup that can efficiently double the size of W states of arbitrary size. Our scheme advances the use of W states in real-world quantum networks and could be extended to other physical systems.
  • Yayın
    Optimal deployment in randomly deployed heterogeneous WSNs: A connected coverage approach
    (Academic Press Ltd- Elsevier Science Ltd, 2014-11) Sevgi, Cüneyt; Koçyiğit, Altan
    Wireless 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
    Local elections and the Turkish voter: Looking for the determinants of party choice
    (Routledge Journals, 2014-10-02) Kalaycıoğlu, Mahmut Ersin
    On 30 March 2014 Turkish voters elected their local (city) councillors. Their party preferences seem to indicate considerable correspondence with the national vote choices. So, do voters' choices in local elections differ from voters' party preferences at the national legislative elections? Based on previous research findings on Turkish voting behaviour, a list of hypotheses was compiled and tested, using binary logistic regression analyses and survey data collected immediately prior to the 2009 and 2014 local elections. The main findings are that the party lists are supported at the ballot boxes on the basis of the voters' party identification, ideological positions, and economic (dis)satisfaction, whether in national or local elections.
  • Yayın
    Design science perspective on NFC research: Review and research agenda
    (Slovensko Drustvo Informatika, 2013) Aydın, Mehmet Nafiz; Özdenizci Köse, Büşra
    Near Field Communication (NFC), as one of the emerging and promising technological developments, provides means to short range contactless communication for mobile phones and other devices alike. NFC has become an attractive design science research area for many academicians due to its exploding growth and its promising applications and related services. A better understanding of the current status of NFC research is necessary to maintain the advancement of knowledge in NFC research and to identify the gap between theory and practice. In this paper, we present a literature review on NFC. To facilitate the analysis of the literature, we propose a research framework and organize the NFC literature into four major categories (theory and development, applications and services, infrastructure, ecosystem). We contend that due to the nature of NFC (industry high stakes, multidisciplinary research, artifacts development), the design science research paradigm serves an appropriate ground to investigate an extent to which relevance and rigor is achieved. By employing the proposed research framework and design science perspective, we set up a research agenda (research directions and promising research questions) which may help practitioners and academics to achieve a substantial progress in NFC.
  • Yayın
    Constructing quantum logic gates using q-deformed harmonic oscillator algebras
    (Springer, 2014-04) Altıntaş, Azmi Ali; Özaydın, Fatih; Yeşilyurt, Can; Buğu, Sinan; Arık, Metin
    We study two-level q-deformed angular momentum states, and using q-deformed harmonic oscillators, we provide a framework for constructing qubits and quantum gates. We also present the construction of some basic one-qubit and two-qubit quantum logic gates.
  • Yayın
    A novel method to design wideband power amplifier for wireless communication
    (IEEE, 2013) Köprü, Ramazan; Kuntman, Hulusi Hakan; Yarman, Bekir Sıddık Binboğa
    A new approach is presented to design microwave amplifiers to deliver maximum output power using Simplified Real Frequency Technique (SRFT). Proposed method tracks the maximum stable gain (MSG) curve of the active device (BJT, FET etc.) under consideration. Maximum Stable Gain Amplifier (MSGA) possesses higher gain than that of the constant or Flat Gain Amplifier (FGA) along the operating frequency band. Compared to FGA, it is this feature that makes MSGA high efficiency and low DC power consumption amplifier. Employing the proposed design method, a MSG power amplifier is constructed over the frequency band of 800-5200 MHz which can be utilized for GSM, UMTS, Wi-Fi and Wi-MAX applications.