Browsing İşletme Fakültesi by Author "Dağ, Hasan"
Now showing items 21-38 of 38
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On the selection of ınterpolation points for rational Krylov Methods
Yetkin, E. Fatih; Dağ, Hasan (Springer-Verlag Berlin, 2012)We suggest a simple and an efficient way of selecting a suitable set of interpolation points for the well-known rational Krylov based model order reduction techniques. To do this some sampling points from the frequency ... -
On-Line Transient Stability Assessment Using Matlab Parallel Programming Environment
Soykan, Gürkan; Dağ, Hasan (IEEE, 2010)Transient Stability Assessment (TSA) is the major part of Dynamic Security Assessment (DSA) in an electric power system. On-line TSA has gained more importance for power system security in last two decades. The decreasing ... -
Parallel Contingency Analysis Using Differential Evolution Based Solution For Branch Outage Problem
Ceylan, Oğuzhan; Dağ, Hasan; Özdemir, Aydoğan (IEEE, 2010)Contingency analysis is one of the most fundamental work an electricity management center operator has to perform regularly. If both bus voltage magnitudes and reactive power flowing on the branches during any type of ... -
Parallel Implementation Of Iterative Rational Krylov Methods For Model Order Reduction
Yetkin, E. Fatih; Dağ, Hasan (IEEE, 2010)Model order reduction (MOR) techniques are getting more important in large scale computational tasks like large scale electronic circuit simulations. In this paper we present some experimental work on multiprocessor systems ... -
Parallel implementation of iterative rational Krylov methods for model order reduction
Yetkin, Emrullah Fatih; Dağ, Hasan (IEEE, 2009)Model order reduction (MOR) techniques are getting more important in large scale computational tasks like large scale electronic circuit simulations. In this paper we present some experimental work on multiprocessor systems ... -
Parallel-in-space implementation of transient stability analysis on a Linux cluster with infiniband
Soykan, Gürkan; Flueck, Alexander J.; Dağ, Hasan (IEEE, 2012)On-line transient stability analysis is an inevitable way to provide real time power system security and control. Parallel computing is one of the most viable ways to perform on-line transient stability analysis. This paper ... -
Post outage bus voltage calculations for double branch outages
Ceylan, Oğuzhan; Ozdemir, Aydogan; Dağ, Hasan (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 ... -
Post-outage state estimations for outage management
Ceylan, Oğuzhan; Ozdemir, Aydogan; Dağ, Hasan (IFAC Secretariat, 2011)Real time outage information is required to the utility operators for outage management process. In addition to some basic information regarding the outage post-outage system status will help to improve the response to ... -
Power flow using thread programming
Dağ, Hasan; Soykan, Gürkan (2011)Power flow problem which is one of the most important applications in power system is solved using OpenMP Application Program Interface (API) a thread based programming technique for the shared memory programming environments. ... -
A preconditioner for transient stability time domain simulation
Soykan, Gürkan; Flueck, Alexander J.; Dağ, Hasan (2011)Transient Stability analysis which is one of the most important tasks of power system dynamic security analysis determines the dynamic behaviour of the power system after a large disturbance. Differential and algebraic ... -
Protecting openflow switches against denial of service attacks
Bahaa-Eldin, Ayman M.; ElDessouky, Ebada Mohamed Essam Eldin Ibrahim; Dağ, Hasan (Institute of Electrical and Electronics Engineers Inc., 2018)This paper presents a novel approach to protect Openflow switches against a type of Denial of Service (DoS) attacks. Openflow switches are the core of Software Defined Networks (SDN) and they are very flexible programmable ... -
Random CapsNet forest model for imbalanced malware type classification task
Çayır, Aykut; Ünal, Uğur; Dağ, Hasan (Elsevier, 2021)Behavior of malware varies depending the malware types, which affects the strategies of the system protection software. Many malware classification models, empowered by machine and/or deep learning, achieve superior ... -
A Recommender Model Based on Trust Value and Time Decay Improve the Quality of Product Rating Score in E-commerce Platforms
Işık, Muhittin; Dağ, Hasan (IEEE, 2017)Most of the existing products rating score algorithms do not take fake accounts and time decay of users' ratings into account when creating the list of recommendations. The trust values and the time decay of users' ratings ... -
Sparsity Preserving Computation for Spectral Projectors
Yetkin, E. Fatih; Dağ, Hasan (Amer Inst Physics, 2011)Several areas of applications such as model order reduction preconditioner design and eigenvalue problems for spectral projectors can be found in the literature. In this paper a fast and sparsity preserving approach for ... -
A sparsity-preserving spectral preconditioner for power flow analysis
Yetkin, Emrullah Fatih; Dağ, Hasan (TUBITAK Scientific & Technical Research Council Turkey, 2016)Due to the ever-increasing demand for more detailed and accurate power system simulations the dimensions of mathematical models increase. Although the traditional direct linear equation solvers based on LU factorization ... -
A spectral divide and conquer method based preconditioner design for power flow analysis
Dağ, Hasan; Yetkin, Emrullah Fatih (2010)Power system simulations most of the time require solution of a large sparse linear system. Traditional methods such as LU decomposition based direct methods are not suitable for parallelization in general. Thus Krylov ... -
Towards Faster Branch Outage Simulations Using Simulated Annealing and Parallel Programming
Ceylan, Oğuzhan; Özdemir, Aydoğan; Dağ, Hasan (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 ... -
Website category classification using fine-tuned BERT language model
Demirkıran, Ferhat; Çayır, Aykut; Ünal, Uğur; Dağ, Hasan (Institute of Electrical and Electronics Engineers Inc., 2020)The contents on the Word Wide Web is expanding every second providing web users a rich content. However, this situation may cause web users harm rather than good due to its harmful or misleading information. The harmful ...