İşletme Fakültesi

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Citation - Scopus: 0
Trust, Confidence and E-Commerce in Cyberspace
(2002) Güzey, Y.Y.
The trust, confidence and e-commerce issues in cyberspace are discussed. Development of commercial activities in the cyberspace hinges on assuring consumers and businesses that their use of network services were safe, secure and reliable. E-commerce requires trust across the spectrum of users and providers of services and goods. The cyberspace will never be completely secure, reliable, trustworthy and involves a calculated risk.
Citation - Scopus: 0
Attitudes Towards Knowledge Management in Turkish Companies
(2002) Üçdal, Erol; Güzey, Yildiz Y.
Attitudes towards knowledge management in Turkish companies are discussed. More and more companies in Turkish economy are allocating responsibility and a budget for knowledge management. Analysis show that the acts of successful knowledge management strategies brings new types of working giving people the chance to invest in knowledge maintaining the culture change and rewarding employees with new incentive schemes.
Yeni Keynesci Yaklaşımda Ücret ve İstihdam
(İstanbul Üniversitesi, 2002) Bilgin, Mehmet Hüseyin
The purpose of this paper is to explore the new Keynesian approach on wages and employment relationship. According to new Keynesian school, market clearing mechanism does not exist due to rigidities and stickiness. This situation leads involuntary unemployment. In new Keynesian theory, there are three theories to explain wage rigidities and involuntary unemployment. This paper analyzes these theories in detail and discusses the new Keynesian assumptions from the perspective of Turkish labor market.
Citation - Scopus: 8
An Analysis of the Unemployment Selected Mena Countries and Turkey
(2008) Bilgin, Mehmet Hüseyin; Kilicarslan, Ismihan N, I. N.
One of the most important economic and social problems of the Middle East and North Africa (MENA) is the high rate of unemployment. Unemployment in the selected MENA countries like Egypt Israel Jordan and Turkey are examined as well as the relationship between growth and unemployment. For this reason active labor market policies should be designed to address job creation in addition to structural reform in labor markets.
Citation - Scopus: 15
Branch outage solution using particle swarm optimization
(2008) Ceylan, Oğuzhan; Ceylan, Oğuzhan; Ozdemir, Aydogan; Dağ, Hasan; Dağ, Hasan
For post outage MW line flows and voltage magnitude calculations most of the methods use linear methods because of their simplicity. Especially for reactive power flow calculations one can face high errors. In this paper we use a minimization method that minimizes the errors resulting from the linear system model implementation. We solve the optimization problem using particle swarm optimization. We give some outage examples using IEEE 14 bus IEEE 30 bus and IEEE 57 bus data and compare the results with full ac load flow calculation. © 2008 Australasian Universities Power Engineering Conference (AUPEC'08).
Citation - Scopus: 1
Heterosim: Heterogeneous Simulation Framework
(Association for Computing Machinery, 2009) Dursun, Taner; Dağ, Hasan; Dağ, Hasan
In order to arrange heterogeneous simulation executions it would be useful to have simulation tools that enable easy and fast creation of simulation sessions employing real-time software components beside simulation codes. Although there have been considerable amount of research activities in simulation community the current simulation tools are not sufficiently capable to support such a cooperation between components working in real-time and simulation-time. In this paper we propose a new approach for constructing hybrid simulations that leverages usage of simulation systems. We introduce HeteroSim a Java-based simulation system that can execute discrete event simulations by employing both simulation and real world software entities. This model is applicable to many software related areas such as scenario-based software testing and development of simulators. As a case study we are able to rely on this model in order to build simulations combining both the simulated elements of a High Performance Computing (HPC) system and already implemented elements of our Policy Based Management (PBM) framework so-called POLICE [1][2]. In this manner it may be possible to study the efficiency of POLICE on management of HPC systems.
Citation - Scopus: 12
Comparison of Post Outage Bus Voltage Magnitudes Estimated by Harmony Search and Differential Evolution Methods
(2009) Ceylan, Oğuzhan; Ceylan, Oğuzhan; Özdemir, Aydoğan; Dağ, Hasan; Dağ, Hasan; Özdemir, Serpil
Contingency studies are indispensable tools of both the power system planning and operational studies. Real time implementation of operational problems makes necessary the use of high speed computational methods while requiring reasonable accuracies. On the other hand, accuracy of the results and the speed of calculation depend on branch outage modeling as well as solution algorithm used. This paper presents a comparison of post outage bus voltage magnitudes calculated by two meta-heuristic approaches; namely differential evolution (DE) and harmony search (HS) methods. The methods are tested on IEEE 14, IEEE 30, IEEE 57, and IEEE 118 bus test systems and the results are compared both in terms of accuracy and calculation speed.
Citation - Scopus: 1
International Financial Crises and the Political Economy of Financial Reforms in Turkey: 1994-2009
(2009) Şakar, Birgül
This study1 holds for the formation of international financial crisis and political factors for economic crisis in Turkey are evaluated in chronological order. The international arena and relevant studies conducted in Turkey work in the literature are assessed. The main purpose of the study is to hold the linkage between the crises and political stability in Turkey in details and to examine the position of Turkey in this regard. The introduction part follows the literature survey on the models explaining causes and results of the crises the second part of the study. In the third part the formations of the world financial crises are studied. The fourth part financial crisis in Turkey in 1994 2000 2001 and 2008 are reviewed and their political reasons are analyzed. In the last part of the study the results and recommendations are held. Political administrations have laid the grounds for an economic crisis in Turkey. In this study the emergence of an economic crisis in Turkey and the developments after the crisis are chronologically examined and an explanation is offered as to the cause and effect relationship between the political administration and economic equilibrium in the country. Economic crises can be characterized as follows: high prices of consumables high interest rates current account deficits budget deficits structural defects in government finance rising inflation and fixed currency applications rising government debt declining savings rates and increased dependency on foreign capital stock. Entering into the conditions of crisis during a time when the exchange value of the country's national currency was rising speculative finance movements and shrinking of foreign currency reserves happened due to expectations for devaluation and because of foreign investors' resistance to financing national debt and a financial risk occurs. During the February 2001 crisis and immediately following devaluation and reduction of value occurred in Turkey's stock market. While changing over to the system of floating exchange rates in the midst of this crisis the effects of the crisis on the real economy are discussed in this study. Administered politics include financial reforms such as the rearrangement of banking systems. These reforms followed with the provision of foreign financial support. There have been winners and losers in the imbalance of income distribution which has recently become more evident in Turkey's fragile economy.
Citation - WoS: 0
Citation - Scopus: 0
Towards Faster Branch Outage Simulations Using Simulated Annealing and Parallel Programming
(IEEE, 2009) Ceylan, Oğuzhan; Dağ, Hasan; Özdemir, Aydoğan; Ceylan, Oğuzhan; Dağ, Hasan; Özdemir, Serpil
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 optimization problem. To speed up the solution procedure the distributed computing toolbox of Matlab is used as a parallel programming tool. The results of the proposed method are compared to those of full AC method and are discussed both from the point of accuracy and solution speed.
Citation - Scopus: 2
Parallel Implementation of Iterative Rational Krylov Methods for Model Order Reduction
(IEEE, 2009) Yetkin, Emrullah Fatih; Yetkin, Emrullah Fatih; Dağ, Hasan; Dağ, Hasan
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 for rational Krylov methods. These methods require huge memory and computational power especially in large scale simulations. Therefore these methods are fairly suitable for parallel computing. ©2009 IEEE.
Citation - WoS: 0
Citation - Scopus: 0
Dynamic Priority Packet Scheduler With Deadline Considerations (dpd)
(INT INST Informatics & Systemics, 2010) Dağ, Tamer; Dağ, Tamer
Providing quality of service (QoS) to applications with different traffic characteristics based on their needs is an important research area for today's and tomorrow's high speed networks. Various techniques have been proposed to achieve good QoS for diverse application types. Among these techniques packet scheduling algorithms decide on how to process packets at network nodes
Citation - WoS: 0
Parallel Implementation Of Iterative Rational Krylov Methods For Model Order Reduction
(IEEE, 2010) Yetkin, E. Fatih; Dağ, Hasan; Dağ, Hasan; Yetkin, Emrullah Fatih
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 for rational Krylov methods. These methods require huge memory and computational power especially in large scale simulations. Therefore these methods are fairly suitable for parallel computing.
Citation - WoS: 0
Citation - Scopus: 0
Comparison of Cost-Free Computational Tools for Teaching Physics
(IEEE, 2010) Er, Neslihan Fatma; Dağ, Hasan; Dağ, Hasan
It is widely accepted that it is quite difficult to engage today's students, from high schools to university, both in educational activities in class and "teaching" them physics due to their prejudices about the complexity of physics. The difficulty in capturing students' attention in class for a long time also plays a role in less effective teaching during learning activities. Research shows that students learn little from traditional lectures. According to constructivist learning theories, visual aids and hands-on activities play a major role in learning physics. In addition to laboratory work there are many computational tools for teaching physics, which help teachers and students in constructing a conceptual framework. With this in mind, this paper compares freeware and open source computational tools for teaching physics.
Citation - WoS: 1
Citation - Scopus: 1
A Critical Analysis of Current Legal Developments on the Political Participation of Minorities in Turkey
(2010) Akbulut, Olgun; Akbulut, Olgun
This is a follow-up article to the one published in the IJMGR half a decade ago (Vol. 12 2005). Although there have been domestic and international legal cases that are directly concerned with the political participation of minorities in Turkey few improvements have been made in law covering the subject. This encouraged this author to analyse and criticise the judgements of the European Court of Human Rights and the legal and political actors at domestic level. The aim of this article is to reflect upon how international human rights monitoring affects national laws in certain thorny issues such as the rights of minorities. Since the current and previous articles have a common theme and complement each other I strongly recommend reading both articles. © 2010 Martinus Nijhoff Publishers.
Citation - Scopus: 3
A Spectral Divide and Conquer Method Based Preconditioner Design for Power Flow Analysis
(2010) Dağ, Hasan; Yetkin, Emrullah Fatih; Yetkin, Emrullah Fatih; Dağ, Hasan
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 subspace based iterative methods (i.e. Conjugate Gradient Generalized Minimal Residuals (GMRES)) can be used as very good alternatives compared to direct methods. On the other hand Krylov based iterative solvers need a preconditioner to accelerate the convergence process. In this work we suggest a new preconditioner for GMRES which can be used in Newton iteration of power flow analysis. The new preconditioner employs the basic spectral divide and conquer methods and invariant subspaces for clustering the eigenvalues of the Jacobean matrix appears in Newton-Raphson steps of power flow simulation. ©2010 IEEE.
Citation - WoS: 0
Citation - Scopus: 0
Guidelines for It Change Management Shown on an Example in Turkey
(Int Business Information Management Assoc-IBIMA, 2010) Oberer, Birgit; Oberer, Bırgıt; Erkollar, Alptekin
In today's highly technology driven competitive global markets the ability to adopt is the only guarantee of survival. Businesses need to show ability to enable a competitive edge by taking their products or services to markets before the competitors. Today business have to take care that IT systems are able to adapt to the changes caused by our highly technology driven society and the influences of digitalization and globalization to support the needs of businesses quickly and efficiently. The following contribution gives an overview about a work in progress that is defining the guidelines for IT change management in Turkey.
Citation - WoS: 5
Citation - Scopus: 8
Eurasian Geopolitics and Financial Crisis: Transforming Russian-Turkish Relations From Geopolitical Rivalry To Strategic Cooperation
(Routledge Journals Taylor & Francis Ltd, 2010) İşeri, Emre
[Abstract Not Available]
Citation - WoS: 0
Citation - Scopus: 0
On-Line Transient Stability Assessment Using Matlab Parallel Programming Environment
(IEEE, 2010) Soykan, Gürkan; Dağ, Hasan; Dağ, Hasan
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 costs of hardware and advanced package programs and techniques encourage researchers to apply parallel programming to the problems that are either too much time consuming or impossible to solve using serial computers. The real-time evaluation of TSA is now almost possible thanks to such tools and techniques. We demonstrate the use of the parallel computing toolbox of Mat lab for TSA. In this regard IEEE 57 and 118 bus systems are tested with 57 and 56 contingencies respectively. Each contingency requires solution of a transient stability problem. The parallel performance of this implementation is expected to spur researchers to use parallel programming in Mat lab environment. It requires minimal knowledge regarding parallel programming.
Citation - Scopus: 25
Gravitational Search Algorithm for Post-Outage Bus Voltage Magnitude Calculations
(2010) Ceylan, Oğuzhan; Dağ, Hasan; Ozdemir, Aydogan; Ceylan, Oğuzhan; Dağ, Hasan
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.
Citation - Scopus: 4
Harmony Search Method Based Parallel Contingency Analysis
(2010) Ceylan, Oğuzhan; Dağ, Hasan; Dağ, Hasan; Ceylan, Oğuzhan; Ozdemir, Aydogan
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. Several outage simulations using IEEE 14 30 and 118 bus systems are performed and compared against AC power flow in terms of accuracy. In order to speed up the contingency simulation the problem is also solved in a parallel environment. Speed up results of the IEEE 118 and 300 bus test systems are given. ©2010 IEEE.

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