Yazar "Alagoz, B. B." seçeneğine göre listele

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    An analysis of corona field charging kinetics for polydisperse aerosol particles by considering concentration and mobility
    (Iop Publishing Ltd, 2010) Alisoy, H. Z.; Alagoz, B. B.; Alisoy, G. H.
    In this paper, the kinetics of the charging process of polydisperse aerosol particles in a unipolar corona field is analysed and the effects of the particle concentration and particle mobility on the charging kinetics are investigated theoretically. An equation for time constant is derived to evaluate charging time of the particles.
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    An FDTD based numerical analysis of microwave propagation properties in a skin-fat tissue layers
    (Elsevier Gmbh, 2013) Alisoy, H. Z.; Us, S. Barlaz; Alagoz, B. B.
    This study theoretically investigates wave propagation properties at the interface of air-skin-fat tissues for a microwave frequency of 6.8 GHz. For this proposes, propagation of the microwaves in a biological tissue model of skin-fat are numerically analyzed by using FDTD method for the transverse magnetic (TM) mode of 2D-Maxwell's equations. These analyses are conducted for various point source placements such as none-contacting, embedded to skin and embedded to fat configurations. Electric field intensity and SAR distribution across the air-skin-fat tissue layers are revealed. The energy penetration and absorption degrees of planar skin-fat tissue layers are discussed in a physical origin. The large electrical impedance mismatches between the tissue layers result in reflection of microwaves from the interface of layers. Skin layer exhibits a considerable wave reflection property due to the high reflection coefficient at air-skin and skin-fat interfaces. (C) 2013 Elsevier GmbH. All rights reserved.
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    An Investigation of Ionic Flows in a Sphere-Plate Electrode Gap
    (Iop Publishing Ltd, 2013) Alisoy, H. Z.; Alagoz, S.; Alisoy, G. T.; Alagoz, B. B.
    This paper presents analyses of ion flow characteristics and ion discharge pulses in a sphere-ground plate electrode system. As a result of variation in electric field intensity in the electrode gap, the ion flows towards electrodes generate non-uniform discharging pulses. Inspection of these pulses provides useful information on ionic stream kinetics, the effective thickness of ion cover around electrodes, and the timing of ion clouds discharge pulse sequences. A finite difference time domain (FDTD) based space-charge motion simulation is used for the numerical analysis of the spatio-temporal development of ionic flows following the first Townsend avalanche, and the simulation results demonstrate expansion of the positive ion flow and compression of the negative ion flow, which results in non-uniform discharge pulse characteristics.
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    Modeling and analysis of dielectric materials by using gradient-descent optimization method
    (World Scientific Publ Co Pte Ltd, 2017) Alagoz, B. B.; Alisoy, H. Z.; Koseoglu, M.; Alagoz, S.
    This study presents a numerical method based on parallel RC equivalent circuit model fitting methodology for analysis and modeling of dielectric materials. The proposed method employs gradient-descent optimization method (GDOM) to estimate parallel RC equivalent circuit model from current waveforms by minimizing sum of squared difference (SSD) error. Estimation of parallel RC equivalent circuit parameters from measured current waveforms provides a useful tool for identification, simulation and analysis of dielectric materials. Moreover, applications of the proposed method for time and frequency analyses of dielectric materials are demonstrated numerically. Numerical simulations were presented to discuss efficiency of the proposed method for modeling, analysis and monitoring of insulator materials.
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    Negative refractions by triangular lattice sonic crystals in partial band gaps
    (Iop Publishing Ltd, 2015) Alagoz, S.; Alagoz, B. B.; Sahin, A.; Nur, S.
    This study numerically demonstrates the effects of partial band gaps on the negative refraction properties of sonic crystal. The partial band gap appearing at the second band edge leads to the efficient transmissions of scattered wave envelopes in the transverse directions inside triangular lattice sonic crystal, and therefore enhances the refraction property of sonic crystal. Numerical simulation results indicate a diagonal guidance of coupled scattered wave envelopes inside crystal structure at the partial band gap frequencies and then output waves are restored in the vicinity of the output interface of sonic crystal by combining phase coherent scattered waves according to Huygens' principles. This mechanism leads to two operations for wavefront engineering: one is spatial wavefront shifting operation and the other is convex-concave wavefront inversion operation. The effects of this mechanism on the negative refraction and wave focalization are investigated by using the finite difference time domain (FDTD) simulations. This study contributes to a better understanding of negative refraction and wave focusing mechanisms at the band edge frequencies, and shows the applications of the slab corner beam splitting and SC-air multilayer acoustic system.
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    A numerical method for the analysis of polydisperse aerosol particles charging in a coaxial electrode system
    (Elsevier Science Bv, 2012) Alisoy, H. Z.; Alagoz, S.; Alisoy, G. H.; Alagoz, B. B.
    In this paper, charging kinetics of polydisperse aerosol particles in a corona field of a coaxial electrode system is numerically analyzed for a logarithmic normal distribution of aerosol particle size. The particle charging and the particle current are calculated by using a charging model considering ion concentration and particle mobility. Particle charging profiles under varying ion density and electrical field intensity distributions of the charging chamber were revealed. A low charging profile in the transition region of bipolar corona field was demonstrated in the simulation results. (C) 2011 Elsevier B.V. All rights reserved.
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    Optimal Fractional Order PID Controller Design for Fractional Order Systems by Stochastic Multi Parameter Divergence Optimization Method with Different Random Distribution Functions
    (Ieee, 2019) Ates, A.; Alagoz, B. B.; Chen, Y. Q.; Yeroglu, C.; HosseinNia, S. Hassan
    This paper modifies Stochastic Multi Parameter Divergence Optimization Method (SMDO) by using some types of random distribution functions in order to show effects of different random distribution functions on optimization performance. SMDO is a parameter wise random search algorithm in random walk class. A prominent feature of SMDO method lies in using random number with standard uniform distribution while diverging a parameter of solution point in backward and forward directions to reach an optimal solution. SMDO method benefits from the success of random backward and forward divergences. This study investigates effects of four types of random distribution functions on performance of SMDO algorithm for controller tuning problem. These distributions are Chi-Square Distribution (CSD), Rayleigh Distribution (RD), Log Normal Distribution (LND) and Uniform random (LTD) distribution. To illustrate effects of these random distribution functions, SMDO is employed to fractional order PID (FOPID) controller tuning problems for fractional order model (FOM) and results obtained for different distribution functions are demonstrated.
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    Spatio-spectral analyses of electromagnetic wave energy absorption and heating effect
    (Elsevier Gmbh, 2014) Alisoy, H. Z.; Alagoz, B. B.; Us, S. Barlaz; Deniz, F. N.; Alagoz, S.
    This study presents a theoretical analysis method to calculate electromagnetic (EM) wave power absorption spectrum of materials by using attenuation coefficients. The heating effect of EM waves is modeled to analyze spectral distribution of temperature rises inside material body as a result of EM wave power absorption. These analyses are very useful for the investigation of electromagnetic wave-material interaction on the bases of electro-physical material parameters (permittivity, permeability and conductivity). An illustrative analysis of spatio-spectral distribution of EM wave energy absorption and resulting heating effect were conducted for muscle tissues and the results are discussed. (C) 2014 Elsevier GmbH. All rights reserved.
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    A user-mode distributed energy management architecture for smart grid applications
    (Pergamon-Elsevier Science Ltd, 2012) Alagoz, B. B.; Kaygusuz, A.; Karabiber, A.
    Future smart grids will require a flexible, observable, and controllable network architecture for reliable and efficient energy delivery under uncertain conditions. They will also necessitate variability in distributed energy generators and demand-side loads. This study presents a tree-like user-mode network architecture responding to these requirements. The approaches presented for the next-generation grid architecture facilitate the management of distributed generation strategies based on renewable sources, distributed storage, and demand-side load management. The authors draw a framework for the future digital power grid concept and assess its viability in relation to volatile, diverse generation and consumption possibilities. In this sense, probabilistic energy balance analyses of tree-like user-mode networks with a stochastic end-user population are conducted to investigate the energy reliability of the proposed grid. A case study based on published generation and consumption profile data is also presented, and several generation scenarios formed by variants of this data are discussed. (c) 2012 Elsevier Ltd. All rights reserved.