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Listeleniyor 1 - 10 / 44
  • Yayın
    On the sensitivity of desirability functions for multiresponse optimization
    (American Institute of Mathematical Sciences, 2008-11) Aksezer, Sezgin Çağlar
    Desirability functions have been one of the most important multiresponse optimization technique since the early eighties. Main reasons for this popularity might be counted as the convenience of the implementation of the method and it's availability in many experimental design software packages. Technique itself involves somehow subjective parameters such as the importance coefficients between response characteristics that are used to calculate overall desirability, weights used in determining the shape of each individual response and the size of the specification band of the response. However, the impact of these sensitive parameters on the solution set is mostly uninvestigated. This paper proposes a procedure to analyze the sensitivity of the important characteristic parameters of desirability functions and their impact on pareto-optimal solution set. The proposed procedure uses the experimental design tools on the solution space and estimates a prediction equation on the overall desirability to identify the sensitive parameters. For illustration, a classical desirability example is selected from the literature and results are given along with the discussion.
  • Yayın
    A designing practice and two coding practices for extreme programming (XP)
    (Springer Verlag, 2003) Yıldız, Mustafa; Kuru, Selahattin
    This paper introduces three new XP practices and reports the experience of applying them to web based software development. These are issue- based programming, comment-first coding and just in time code ownership. The example project is development of an on-line student information and registration software for a university.
  • Yayın
    Driver recognition using gaussian mixture models and decision fusion techniques
    (Springer-Verlag Berlin, 2008) Benli, Kristin Surpuhi; Düzağaç, Remzi; Eskil, Mustafa Taner
    In this paper we present our research in driver recognition. The goal of this study is to investigate the performance of different classifier fusion techniques in a driver recognition scenario. We are using solely driving behavior signals such as break and accelerator pedal pressure, engine RPM, vehicle speed; steering wheel angle for identifying the driver identities. We modeled each driver using Gaussian Mixture Models, obtained posterior probabilities of identities and combined these scores using different fixed mid trainable (adaptive) fusion methods. We observed error rates is low as 0.35% in recognition of 100 drivers using trainable combiners. We conclude that the fusion of multi-modal classifier results is very successful in biometric recognition of a person in a car setting.
  • Yayın
    Failure of an exchange-rate-based stabilization plan in Turkey
    (M E Sharpe, 2003-02) Gökkent, Giyas; Moslares, Carlos; Amiel-Saenz, Rafael
    The Turkish exchange-rate-based stabilization plan adopted in 2000 has been a spectacular failure, lasting a mere fourteen months despite a relatively flexible peg regime and preannounced exit strategy. The final three months of the currency regime were marred by the eruption of a banking sector crisis that quickly developed into a currency crisis, quelled only by external loans and a blanket guarantee by the sovereign of all banking sector liabilities. This was ultimately to no avail as the lira was allowed to float following a full-fledged currency crisis in late February 2001. The usual indicators of crisis did not point to imminent turmoil in November 2000 despite widespread concern about eventual dire developments. To identify the source of the November crisis, one must weigh the factors that led economic agents, and banks in particular, to expect higher interest rates after the fall.
  • Yayın
    Small molecule sorption and desorption in and out of iota-carrageenan gels
    (Taylor & Francis Group, 2007-08) Ataman, Evren; Pekcan, Mehmet Önder
    Small molecule sorption and desorption in and out of Iota-Carrageenan was studied by using steady-state fluorescence (SSF) technique. Pyranine dissolved in water used as fluorescence probe. Fluorescence emission intensity, I-p from pyranine was monitored for studying sorption and desorption processes at various temperatures. The Fickian model was applied to produce sorption, D-s, early desorption, D-ed, and desorption, D-d, coefficients. Corresponding activation energies were obtained and found to be 20.5 kJ mol(-1), 7.0 kJ mol(-1) and 34.9 kJ mol(-1), respectively. The observed D-ed value is an order of magnitude smaller than the D-s and D-d coefficients. On the other hand, sorption processes were shown to be twice as fast as desorption processes.
  • Yayın
    Temperature effect on drying and swelling of kappa carrageenan gels: A steady state fluorescence study
    (Wiley-V C H Verlag GMBH, 2008) Tarı İlgin, Özlem; Pekcan, Mehmet Önder
    A novel technique based on in situ steady state fluorescence (SSF) measurements is introduced for studying drying and swelling Of kappa(-) carrageenan (kappa carrageenan) gels at various temperatures. kappa(-) carrageenan gels were completely dried and then swelled in water vapor. Pyranine was embedded in kappa(-) carrageenan and used as a fluorescence probe. Scattered light intensities, I-SC and fluorescence intensities, I were monitored during the drying and swelling Of kappa(-) carrageenan gels. it was observed that the fluorescence intensity decreased linearly as drying time was increased. A simple model consisting of Case II diffusion was used to quantify the drying processes of the kappa(-) carrageenan gels. This moving boundary model provided packing constant, kappa(o). During swelling, fluorescence intensity increased exponentially as time is increased. The increase in I, was modeled using Li-Tanaka equation from which swelling time constants, tau(c) and cooperative diffusion coefficients, D-c were determined. It was observed that swelling time constants, tau(c) decreased and diffusion coefficients, D-c increased as the swelling temperature was increased. Activation energies for drying and swelling were also obtained and found to be 53.9 and 47.2 kJ mol(-1), respectively.
  • Yayın
    Classification-based macroblock layer rate control for low delay transmission of H.263 video
    (IS & T - Soc Imaging Science Technology, 2003-07) Bayazıt, Uluğ
    Puri and Aravind's method of macroblock bit count estimation for video rate control is based on the classification of the macroblock data into discrete classes and assigning a unique non-linear estimate for each class and quantization parameter pair. This method stands apart from other methods in the literature, since the model of the bit count versus the quantization parameter relation, parameterized by macroblock variance, is a discrete model generated solely from measurements, We extend their technique for low-delay video rate control (tight buffer regulation) in two ways. We propose a strategy of near-uniform quantization parameter assignments to the macroblocks of a frame that can come close to maximizing an objective spatial quality function, such as PSNR, over the entire frame. We also adaptively update the quantization parameter assignments for the yet to be coded macroblocks, after the encoding of each macroblock, to compensate for any errors in the bit count estimation of the encoded macroblock. Our experiments demonstrate that the proposed rate control method can more accurately control the number of bits expended for a frame, as well as yield a higher objective spatial quality than the method adopted by TMN8.
  • Yayın
    Monovalent and divalent cation effects on phase transitions of iota-carrageenan
    (Sage Publications Ltd, 2007-01) Kara, Selim; Arda, Ertan; Pekcan, Mehmet Önder
    Phase transitions Of L-carrageenan in a variety of monovalent (Li, Na, K) and divalent (Mg, Ca, Sr) cation solutions were studied during heating and cooling by using photon transmission technique. Photon transmission intensity (I-tr) was monitored against temperature to determine the transition temperatures and activation energies during the heating and cooling processes in the monovalent and divalent systems. Three distinct transition regions were observed during the heating and cooling cycles for the carrageenan-divalent salt system. At the first step of the heating process, dimer groups were transformed into dimers that presented (g-d) transitions, then these dimers were directly converted into a double helix by undergoing a (d-h) transition. In the higher temperature region, a double helix-to-coil (h-c) transition took place. During the cooling process, these transitions are arranged in the order of (c-h), (h-d), and (d-g). The carrageenan-monovalent salt system presented only coil-to-rod-like helix (c-r) and rod-like helix-to-coil (r-c) transitions during the cooling and heating processes, respectively. A hysteresis was observed between (r-c)-(c-r) and (g-d)-(d-g) transitions for the monovalent and divalent cations, respectively.
  • Yayın
    Local democracy online: An analysis of local government web sites in England and Wales
    (IGI Global, 2006-07) Pratchett, Lawrence; Wingfield, Melvin; Karakaya Polat, Rabia
    This report from the field analyzes the extent to which local authorities in England and Wales have responded to the e-democracy agenda by examining their Web sites and assessing their potential to deliver democracy. The analysis of Web sites provides a powerful insight into how local government is using the Internet to promote democracy. Two aspects of Web site use are particularly significant. First, the analysis reveals the overall commitment to e-democracy in local government, as it is a measure of actual behavior rather than simply an attitudinal survey. Second, it highlights the types of democratic structure being supported and the values being emphasized in the implementation of e-democracy. The research demonstrated that the potential of the Internet for enhancing democracy is not fully exploited by local authorities and there remain considerable variations between different authorities.
  • Yayın
    ICamp - The educational web for higher education
    (Springer Verlag, 2006) Kieslinger, Barbara; Wild, Fridolin; Arsun, Onur İhsan
    iCamp is an EC-funded research project in the area of Technology Enhanced Learning (TEL) that aims to support collaboration and social networking across systems, countries and disciplines in higher education. The concept of an iCamp Space will build on existing interfaces and integrate shared community features. Interoperability amongst different open source learning systems and tools is the key to successful sustainability of iCamp. The content for this collaboration within social communities is provided via distributed networked repositories including, for example, content brokerage platforms, online libraries, and learning object databases. The innovative pedagogical model of iCamp is based on social constructivist learning theories. iCamp creates an environment for a new way of social networking in higher education that puts more emphasis on self-organised, self-directed learning, social networking and cross-cultural collaboration.