İşletme Fakültesi

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Citation Count: 1
Active and Reactive Power Load Profiling Using Dimensionality Reduction Techniques and Clustering
(Institute of Electrical and Electronics Engineers Inc., 2019) Ceylan, Oğuzhan; Ceylan, Oğuzhan; Papadopoulos, Theofilos A.; Kazaki, Anastasia G.; Barzegkar-Ntovom, Georgios A.
This paper proposes a methodology to characterize active and reactive power load profiles. Specifically, the approach makes use of fast Fourier Transform for conversion into frequency domain, principle component analysis to reduce the dimension and K-means++ to determine the representative load profiles. The data set consists of five-year measurements taken from the Democritus University of Thrace Campus. Test days were also classified as working and non-working. From the results it is observed that the proposed methodology determines representative load profiles effectively both regarding active and reactive power.
Citation Count: 0
Analysis and Implications of the Giant Component for an Online Interactive Platform
(Int Business Information Management Assoc-IBIMA, 2016) Aydın, Mehmet Nafiz; Perdahci, N. Ziya
This research is concerned with practical and research challenges related to understanding the nature of online interactive platforms. So-called network science is adopted to investigate the very nature of these systems as complex systems. In this regard we examine an online interactive health network and show that the interactive platform examined exhibits essential structural properties that characterize most real complex networks. We basically look into the largest connected component so-called a giant component (GC) to better understand how the representative network has established. In particular we apply dynamic network analysis to investigate how the GC has evolved over time. We identify a particular pattern towards emerging a GC. Implications of the patterns have been elaborated from a management perspective. We recommend that the basic stages of the emergence of the GC might be of interest to platform managers while evaluating performance of online platforms.
Citation Count: 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 Count: 7
Anytime. Everywhere. Mobile learning in higher education: creating a GIS course
(Springer-Verlag Berlin, 2012) Oberer, Bırgıt; Oberer, Birgit
The course concepts introduced in this contribution were implemented in 2011 in a university in Turkey and show an approach for integrating mobile learning modules in higher education. The results of the course show the advantages as well as potential for improvement of the system and the use of it in higher education.
Citation Count: 0
Applications of Eigenvalue Counting and Inclusion Theorems in Model Order Reduction
(Springer-Verlag Berlin, 2010) Dağ, Hasan; Dağ, Hasan
We suggest a simple and an efficient iterative method based on both the Gerschgorin eigenvalue inclusion theorem and the deflation methods to compute a Reduced Order Model (ROM) to lower greatly the order of a given state space system. This method is especially efficient in symmetric state-space systems but it works for the other cases with some modifications.
Citation Count: 46
Assessing quality in higher education: New criteria for evaluating students' satisfaction
(Taylor & Francis, 2011) Zineldin, Mosad; Akdag, Hatice Camgöz; Vasicheva, Valentina
The aim of this research is to present a new quality assurance model (5Qs) and to examine the major factors affecting students' perception of cumulative satisfaction. The model includes behavioural dimensions of student satisfaction. The factors included in this cumulative summation are technical functional infrastructure interaction and atmosphere of higher education institutions. This study concerns students in higher education institutions in Istanbul Turkey. The questionnaire contains a total of 39 items (attributes) of newly developed five quality dimensions (5Qs). A total of 1641 complete and usable questionnaires was received. Frequency analysis factor analysis and reliability analysis were used for analysing the data collected. Inspection of scree plot and eigenvalues enabled the analysis to reduce the 39 quality attributes to seven factors. The results can be used by higher education institutions to re-engineer and re-design creatively their quality-management processes and the future direction of their more effective education quality strategies. © 2011 Taylor & Francis.
Citation Count: 3
Assessment of Harmonic Distortion on Distribution Feeders with Electric Vehicles and Residential PVs
(IEEE, 2017) Ceylan, Oğuzhan; Paudyal, Sumit; Dahal, Sudarshan; Karki, Nava R.
Power-electronic interfacing based devices such as photovoltaic (PV) panels and electric vehicles (EVs) cause voltage/current harmonic distortions on the power grid. The harmonic current profiles from EVs and PVs depend on the design of the controllers integrated to the PV inverters and EV chargers. Similarly the voltage and current harmonic distortions on a grid change throughout the day as the PV output power number of grid connected EVs and the other load pattern change. In this context we present harmonic assessment to demonstrate cumulative effect of large number of EVs and PVs on a medium voltage distribution grid. We will demonstrate the case studies on the IEEE 123-node distribution feeder with 20% 50% and 100% PV and EV penetrations based on time series simulations carried out for an entire day.
Citation Count: 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.
Citation Count: 0
"Bağımsız Mali Müşavirlerin Müşteri Seçimine Etki Eden Faktörlerin ve Karar Alternatiflerinin AHP ve MAUT Yöntemleri Çerçevesinde Değerlendirilmesi: İstanbul Kentine İlişkin Bir Uygulama"
(Türmob, 2019) Çanakçıoğlu, Mustafa
Bağımsız Serbest Muhasebeci Mali Müşavirlerin (SMMM) güven, doğruluk ve bilgiye dayanan uzun süreli bir ticari ilişki içerisinde bulunacakları müşterilerinin seçimi sırasında alacakları kararların sonuçları aslında sadece bu iki tarafı değil, işletmenin tüm paydaşlarını da etkilemektedir. Mali müşavirlerin verdikleri hizmetlerin çeşitlenmesinden ve karar alma süreçlerine çok sayıda faktör ve değişkenin etki etmesinden dolayı karar alıcıların kişisel tecrübe ve yargılarına bağlı olarak doğru, hızlı ve güvenilir karar almaları son derece zorlaşmıştır. Bu nedenle karar alma süreçleri için sistematik ve yapısal bir çerçeve ortaya koymak amacıyla çok kriterli karar verme (ÇKKV) yöntemlerinin kullanılması ihtiyaç haline gelmiştir. Bu çalışmada Analitik Hiyerarşi Proses (AHP) yöntemi ile birlikte AHP ve Multiple Attribute Utility Theory (MAUT) yöntemlerinden oluşan hibrid bir model önerilmektedir. Modelde 13 tane seçim kriteri ve 4 tanede karar alternatifi belirlenmiştir. Mali müşavirlerin müşteri seçim kriterleri ve karar alternatifleri için önce AHP yöntemi kullanılarak seçim kriterleri ağırlıklandırılırken, karar noktaları için göreli önem değerleri belirlenmiştir. Modelin ikinci aşamasında AHP yöntemi ile MAUT yönteminin entegre edildiği hibrid bir model kullanılmış, AHP ile seçim kriterleri ağırlıklandırılırken, MAUT yöntemi ile karar alternatiflerinin önem değerleri hesaplanmıştır. Her iki farklı yöntem çerçevesinde elde edilen sonuçlar gözden geçirilmiş, önerilen modelin uygulanabilirliği iki farklı model çerçevesinde test edilmiştir.
Citation Count: 29
Bank credit in uncertain times: Islamic vs. conventional banks
(Elsevier Ltd, 2020) Bilgin, Mehmet Hüseyin; Danışman, Gamze Öztürk; Demir, Ender; Tarazi, Amine
This paper explores whether the impact of economic uncertainty on credit growth differs for Islamic vs. conventional banks. Using a sample of 416 banks (58 Islamic and 358 conventional) in 12 countries, the findings indicate that an increase in economic uncertainty significantly decreases the credit growth of conventional banks but does not have any significant impact on Islamic banks’ credit growth. Our results are robust to alternative specifications and addressing endogeneity concerns using GMM estimators. We further observe that our findings are stronger for the following countries: (1) countries with explicit deposit insurance protection system for Islamic banks, (2) lower foreign dominance, and (3) countries with a higher share of deposits and assets in Islamic banks.
"BANKA PERFORMANSININ ENTROPİ VE COPRAS YÖNTEMİ İLE DEĞERLENDİRİLMESİ: TÜRK BANKACILIK SEKTÖRÜ ÜZERİNE BİR ARAŞTIRMA"
(İstanbul Serbest Muhasebeci Mali Müşavirler Odası, 2019) Toprak, Mehmet Sabri
Bu çalışmanın amacı, Türkiye’de faaliyet gösteren mevduat bankalarının finansal performansının çok kriterli karar verme yöntemlerinden Entropi ve COPRAS (Complex Proportional ASsessment) yöntemleri ile değerlendirilmesidir. Bu amaçla sektörde aktif büyüklüğü açısından en büyük 11 bankanın 2017 dönemine ilişkin finansal tablolarından hesaplanan verileri kullanılmıştır. Bankalara ait özkaynaklar, mevduatlar, personel giderleri, personel sayısı ve şube sayısı girdi faktörleri olarak kullanılırken, krediler, net faaliyet karı, aktif karlılık oranı ve özkaynak karlılık oranı ise çıktı faktörleri olarak seçilmiştir. Türk bankalarının finansal performansının değerlendirilmesinde Entropi ve COPRAS yöntemlerinin birlikte ilk kez kullanıldığı çalışmada Entropi yöntemiyle seçilen kriterlerin ağırlıkları belirlenmiş, COPRAS yöntemi ile de bankalar performans açısından sıralanmıştır. Çalışma sonucunda sektördeki büyük bankaların finansal performans değeri açısından en iyi performansa sahip bankalar olduğu tespit edilmiştir.
Citation Count: 0
BİRLEŞME VE SATIN ALMA İŞLEMLERİNİN ŞİRKET VE SEKTÖR DÜZEYİNDE ETKİLERİ
(2016) Akben Selçuk, Elif; Köksal, Emin; Altıok Yılmaz, Ayşe Dilara
[Abstract Not Available]
BİST KİMYA, PETROL KAUÇUK VE PLASTİK ÜRÜNLER SEKTÖRÜNDEKİ İŞLETMELERİN FİNANSAL PERFORMANSLARININ HİBRİD ÇKKV YAKLAŞIMI ÇERÇEVESİNDE DEĞERLENDİRİLMESİ
(Beykoz Üniversitesi, 2019) Çanakçıoğlu, Mustafa
Bu çalışmada Borsa İstanbul (BIST) imalat sanayinde yer alan kimya, petrol kauçuk ve plastik ürünler sektöründe yer alan firmaların oran analizi yaklaşımı ile birbirleriyle karşılaştırmalı finansal performans analizi yapılmıştır. Çalışma kapsamında 30 işletmenin 2013-2017 tarihleri arasındaki temel mali tablolardan elde edilen 10 finansal oran kriteri kullanılmıştır. Elde edilen veriler “Çok Kriterli Karar Verme” (ÇKKV) yöntemlerinden Entropi ve Gri İlişkiler Analiz (GİA) ile değerlendirilmiştir. Belirlenen seçim kriterlerinin ağırlıkları Entropi tekniği kullanılarak hesaplanmıştır. Ardından GİA yöntemi kullanılarak karar seçeneklerinin göreli önem değerleri hesaplanmış, firmalar her yılın performans değerlerine göre sıralandırılmıştır.
Citation Count: 37
Bitcoin Forecasting Using ARIMA and PROPHET
(IEEE, 2018) Yenidoğan, Işıl; Çayır, Aykut; Kozan, Ozan; Dağ, Tugce; Arslan, Çiğdem
This paper presents all studies methodology and results about Bitcoin forecasting with PROPHET and ARIMA methods using R analytics platform. To find the most accurate forecast model the performance metrics of PROPHET and AMNIA methods are compared on the same dataset. The dataset selected 16r this study starts from May 2016 and ends in March 2018 which is the interval that Bitcoin values changing significantly against the other currencies. Data is prepared for time series analysis by performing data preprocessing steps such as time stamp conversion and feature selection. Although the time series analysis has a univariate characteristics it is aimed to include some additional variables to each model to improve the forecasting accuracy. Those additional variables are selected based on different correlation studies between cryptocurrencies and real currencies. The model selection for both ARIMA and PROPHET is done by using threefold splitting technique considering the time series characteristics of the dataset. The threefold splitting technique gave the optimum ratios for training validation and test sets. Filially two different models are created and compared in terms of performance metrics. Based on the extensive testing we see that PROPHET outperforms ARIMA by 0.94 to 0.68 in R-2 values.
Citation Count: 0
Borsa İstanbul’da İşlem Gören Çimento Firmalarının Entropi-Eatwios Bütünleşik Yaklaşımı İle Finansal Performanslarının Değerlendirmesi
(Yaşar Üniversitesi, 2019) Çanakçıoğlu, Mustafa
Gelişmekte olan ülkelerde inşaat, altyapı ve üstyapı projelerinin gerçekleştirilebilmesi büyük oranda çimento sektörü ile ilişkilidir. Bu nedenle ülkelerin çimento sektörlerine ilişkin performans ve etkinliklerinin ölçülmesi gelecekte büyüme ve gelişme perspektifine ilişkin bir takım göstergeler ortaya koyabilmektedir. Türkiye’nin bu perspektifte ilgili sektörlerinin analizi gelecek projeksiyonu için hayati düzeyde öneme sahiptir. Bu kapsamda, Borsa İstanbul (BİST) Taş, Toprak Endeksinde yer alan çimento işletmelerin finansal performanslarının incelemesi bu çalışmanın temel amacıdır. Bu çalışmada BİST’te işlem gören çimento firmalarının performanslarını analiz etmek üzere çok kriterli karar verme teknikleri olarak kullanılan Entropi ve EATWIOS (Efficiency Analysis Technique with Input Output Satisficing) yöntemlerinden oluşan hibrid bir modelin kullanılması önerilmektedir. Araştırma örneklemi, Borsa İstanbul’da işlem gören 15 çimento üretimi yapan işletmeden oluşmaktadır. Analiz sonucunda en iyi finansal performansa sahip olan çimento işletmesinin Adana Çimento olduğu belirlenmiştir.
Citation Count: 2
Branch outage simulation based contingency screening by gravitational search algorithm
(Praise Worthy Prize Srl, 2012) Ceylan, Oğuzhan; Dağ, Hasan; Dağ, Hasan
Power systems contingency analysis is an important issue for electric power system operators. This paper performs branch outage simulation based contingency screening using a bounded network approach. Local constrained optimization problem representing the branch outage phenomena is solved by the gravitational search algorithm. The proposed method is applied to IEEE 14 30 57 and 118 Bus Test systems and its performance from the point of capturing violations is evaluated. In addition false alarms and the computational accuracy of the proposed method are also analyzed by using scattering diagrams. Finally the proposed gravitational search based contingency screening is compared with full AC load flow solutions from the point of computational speed. Copyright (C) 2012 Praise Worthy Prize S.r.l. - All rights reserved.
Citation Count: 15
Branch outage solution using particle swarm optimization
(2008) Ceylan, Oğuzhan; 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 Count: 1
Case Study 8: IGaranti: Expanding the Frontiers of Mobile Banking Innovation
(Springer International Publishing, 2016) Ozturkcan, Selcen; Tunçalp, Deniz
iGaranti have claimed many awards and recognitions in addition to the wide press coverage. Two years into its launch iGaranti counted for an active user base of 110 k. However the spread of its reach was only about 2?% of the active mobile banking users in the market. Mr. Yilmaz worried about the bottlenecks that had limited further user acceptance and engagement. © Springer International Publishing Switzerland 2017.
Citation Count: 2
Cash holdings and corporate governance: Evidence From Turkey
(IGI Global, 2019) Akben Selçuk, Elif; Şener, Pınar
This chapter investigates the empirical factors affecting corporate cash holdings with special emphasis on corporate governance variables for a sample of Turkish-listed nonfinancial firms over the period 2006 to 2010. The findings reveal a significant non-linear relation between family ownership and cash holdings. In addition, while board structure does not significantly affect the level of cash holdings, tunneling increases cash reserves of firms. Furthermore, the results indicate that cash flow, leverage, other liquid assets that can be used as cash substitutes, the degree of tangibility of assets, and firm size are important in determining cash holdings among Turkish companies.
Citation Count: 0
Choice of finance in an emerging market: The impact of independent decisions politics and religion
(Springer International Publishing, 2017) Davutyan, Nurhan; Öztürkkal, Belma
This paper is based on a KONDA 1 Research and Consultancy 2 survey conducted in May 2014 on 2607 people forming a representative sample of the Turkish population. It focuses on how people’s religious and political characteristics impact the independence of their decision making regarding saving and borrowing. An earlier study by Davutyan and Ozturkkal (2016) reports saving and borrowing decisions strongly correlate with income, education, marital status and region within country. Furthermore, 54% of those surveyed did not save and the main motivation for those who saved was to finance children’s education or home purchase. Religious people and those with a conservative lifestyle are less likely to borrow from family and friends. Older, married and working individuals are more likely to have difficulty paying back loans. According to the results of this survey, religious individuals are less likely to independently decide on their investment choices. Thus, religious people tend to make investment decisions together with family, elderly and respected relatives.

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