Now showing items 1-15 of 15

  • Design of broadband microwave amplifiers with mixed-elements via reflectance data modeling 

    A practical method is introduced to design single-stage broadband microwave amplifiers with mixed lumped and distributed elements via modeling the reflectance data obtained from lumped-element input and output matching network prototypes. The same transducer power gain level is obtained by using less number of lumped-elements in the mixed-element amplifier than that of the lumped-element amplifier prototype. A mixed-element amplifier design is presented to exhibit the utilization of the method. ...

  • Design of distributed-element RF filters via reflectance data modeling 

    A reflectance-based modeling method is presented to obtain the distributed-element counterpart of a lumped-element network which is described by measured or computed reflectance data at a set of frequencies. Numerical generation of the scattering parameters forms the basis of this modeling tool. It is not necessary to select a circuit topology for the distributed-element model which is the natural consequence of the modeling process. Our approach supplements the known interpolation methods by a ...

  • Design of practical matching networks with lumped elements via modeling 

    Authors:Yarman, Sıddık Binboğa; Şengül, Metin Y.; Kılınç, Ali
    Publisher and Date:(IEEE, 2007)
    It is a common practice to utilize commercially available software tools to design matching networks for wireless communication systems. Most of these tools require a properly selected matching network topology with good initial element values. Therefore in this paper a practical method is presented to generate matching networks with initial element values. In the implementation process of the proposed method first the driving point immitance data for the matching network is obtained in a straight ...

  • Foster impedance data modeling via singly terminated LC ladder networks 

    In this work a lossless model is developed for the given Foster impedance data. In the model a 2-port short-or open-terminated LC ladder is used. After applying the proposed algorithm a realizable driving-point reactance function that fits the given data is obtained. Next this function is synthesized resulting in the desired model. In the algorithm there is no need to select a circuit topology for the model. Two examples are given to illustrate the utilization of the proposed modeling algorithm.

  • Gravitational search algorithm for post-outage bus voltage magnitude calculations 

    Authors:Ceylan, Oǧuzhan; Ozdemir, Aydogan; Daǧ, Hasan
    Publisher and Date:(2010)
    Branch outage problem is one of the key problems in power system security analysis. This paper solves branch outage problem using a bounded approach. Local constrained optimization problem in the bounded approach is solved by the gravitational search algorithm. Test results of IEEE 14 30 and 118 bus systems are compared to those of ac load flow method in terms of both accuracy and speed.

  • Harmony search method based parallel contingency analysis 

    Authors:Ceylan, Oǧuzhan; Daǧ, Hasan; Ozdemir, Aydogan
    Publisher and Date:(2010)
    Power system security management is one of the key problems in power system analysis. Power system management center operators need to simulate contingencies as fast as possible and take the remedial actions in time. These contingency analyses comprise of the outages of the branches transformers and other power system components. This paper solves branch outage problem using a bounded approach. Harmony search method is used to solve the local constrained optimization problem of the bounded approach. ...

  • In silico design of novel and highly selective cyclooxygenase-2 inhibitors 

    Authors:Mehmetoğlu, Tuğba
    Publisher and Date:(Kadir Has University, 2014)
    For many years, prevention of inflammation is achieved by inhibition of both cyclooxygenase (COX) enzymes; the eventual outcome is gastrointestinal toxicity. Selective inhibitor design for COX-2 initialized just after discovery of two distinct types of COX enzymes. Both isoforms of COX show great similarities at the active sites. It is still essential to find more potent, more selective and reversible COX-2 inhibitors. Crystallographic structures of COX-1 (pdb code: 1Q4G; Ovis aries COX-1 crystallized ...

  • In silico design of selective monoamine Oxidase B inhibitors using indane ring 

    Authors:Altuntas, Serkan
    Publisher and Date:(Kadir Has University, 2013)
    in the present work 209952 analogs of an indane scaffold were created using various fragment moieties at different position of indane ring. CHEMPLP module of GOLD program is utilized in the screening process. in order to obtain additional validation of selectivity and scoring values the first 100 best selective MAO inhibitor candidates are also tested via ChemScore and ASP scoring fuctions of Gold docking software AutoDock 4.2 and AutoDock Vina. inhibition constants and their poses in the active ...

  • Modeling based real frequency technique 

    Authors:Şengül, Metin Y.
    Publisher and Date:(Elsevier GMBH Urban & Fischer Verlag, 2008)
    Usually commercially available software tools are used to design matching networks for wireless communication systems. But a properly selected matching network topology with good initial element values must be supplied to these tools. Therefore in this paper a modeling-based real frequency technique (M-RFT) is presented to generate matching networks with initial element values. In the proposed method output impedance data of the matching network are obtained in terms of ABCD-parameters of the load ...

  • Post outage bus voltage calculations for double branch outages 

    Authors:Ceylan, Oǧuzhan; Ozdemir, Aydogan; Daǧ, Hasan
    Publisher and Date:(IEEE, 2012)
    Secure operation of electrical power systems is vital hence fast and accurate post-outage state calculations are important for contingency analysis. Contingency analysis includes simulations of both the single and double branch outages. This paper presents constrained optimization problem of a recently developed double branch outage model. Harmony search algorithm is used as an optimization tool. IEEE 30 Bus Test system simulation results are given and compared with those of the AC load flow in ...

  • Reflectance-based Foster impedance data modeling 

    Authors:Şengül, Metin Y.
    Publisher and Date:(Fachverlag Schiele Schon, 2007)
    A reflectance-based method is presented to model a set of given Foster impedance data as a lossless singly terminated two-port consisting of lumped-elements in short or open termination. The basis of the new method rests on the interpolation of the given data as a realizable bounded-real (BR) reflection function. The desired circuit model is obtained by synthesizing this function. An algorithm to generate the circuit model is presented and an example is included which illustrates the utilization ...

  • Reflection Modeling Based Broadband Matching Network Design 

    Authors:Şengül, Metin Y.
    Publisher and Date:(Walter De Gruyter, 2017)
    In this paper a new broadband matching network design approach based on reflection modeling is proposed which has two parts: impedance data generation and modeling. In the approach firstly the output impedance data of the matching network is obtained to get the desired flat transducer power gain in the passband. Next the output reflection data are calculated using the obtained impedance data then they are modeled as a bounded real function. Then this function is synthesized and the desired lossless ...

  • Towards faster branch outage simulations using simulated annealing and parallel programming 

    Authors:Ceylan, Oǧuzhan; Ozdemir, Aydogan; Daǧ, Hasan
    Publisher and Date:(IEEE, 2009)
    Contingency studies such as branch outage and generator outage are among important studies of energy management centers operations. Branch outage modeling on the other hand is one of the basic steps of post-outage state estimation of an electrical power system. Real time implementation of the problem brings the necessity of using high speed methods while providing a reasonable accuracy. This paper presents simulated annealing based solution of the branch outage event which is formulated as a local ...

  • Towards Faster Branch Outage Simulations Using Simulated Annealing and Parallel Programming 

    Authors:Ceylan, Oǧuzhan; Özdemir, Aydoğan; Daǧ, Hasan
    Publisher and Date:(IEEE, 2009)
    Contingency studies such as branch outage and generator outage are among important studies of energy management centers operations. Branch outage modeling on the other hand is one of the basic steps of post-outage state estimation of an electrical power system. Real time implementation of the problem brings the necessity of using high speed methods while providing a reasonable accuracy. This paper presents simulated annealing based solution of the branch outage event which is formulated as a local ...