İktisadi ve İdari Bilimler Fakültesi

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Citation - WoS: 21
Citation - Scopus: 21
Business Groups and Internal Capital Markets
(Routledge Journals, Taylor & Francis Ltd, 2007) Gonenc, Halit; Kan, Ozgur B.; Karadagli, Ece C.
We compare the performance of firms affiliated with diversified business groups with the performance of unaffiliated firms in Turkey, all emerging market. We address the question of whether group-affiliated firms create internal capital markets or control large cash flows. Our findings indicate that group affiliation improves a firm accounting performance, but not stock market performance. Deviation of cash-flow rights front voting rights has a negative but insignificant effect on accounting performance, but a significant effect on market performance. We also find that a firm's accounting, but not stock market, performance increases with the level of group diversification. Our results show that internal capital markets play an important role for the existence of business groups in all emerging market context.
Citation - Scopus: 10
Competitiveness of Major Exporting Countries and Turkey in the World Fishery Market: a Constant Market Share Analysis
(2005) Fidan, H.; Klasra, M.A.
The purpose of this study is to examine whether and to what extent the shares of selected countries' fishery exports in the world markets reflect their international competitiveness. The Constant Market Share (CMS) model, which decomposes export growth into some broad components (i.e., structural effects, market effects, commodity effects and competitive effects), is applied to examine this issue. The results of decomposition analysis revealed that structural factors have been more significant in explaining the growth of exports. The growth effects, though, appeared positive for each country, the exports of open economies like Canada, the United States, Iceland and Turkey benefited more from the growth of world exports. The analysis of commodity composition and market effects suggests that countries like Canada, the United States, Iceland and Turkey were pursuing the product differentiation policy and were penetrating in those markets, which have been growing relatively faster. These countries remained committed throughout the sample period (i.e., 1980-2000) to export their diversified products in fast-growing markets. The analysis of competitiveness effects, which are derived as a residual, show that Norway, Spain, the United States, Indonesia, Thailand, sChile and China were strong fishery exporters and increased their competitiveness during the sample period. Copyright © 2005 IAAEM.
Citation - WoS: 18
Citation - Scopus: 23
Computing Non-Stationary (S, S) Policies Using Mixed Integer Linear Programming
(Elsevier Science Bv, 2018) Xiang, Mengyuan; Rossi, Roberto; Martin-Barragan, Belen; Tarim, S. Armagan
This paper addresses the single-item single-stocking location non-stationary stochastic lot sizing problem under the (s, S) control policy. We first present a mixed integer non-linear programming (MINLP) formulation for determining near-optimal (s, S) policy parameters. To tackle larger instances, we then combine the previously introduced MINLP model and a binary search approach. These models can be reformulated as mixed integer linear programming (MILP) models which can be easily implemented and solved by using off-the-shelf optimization software. Computational experiments demonstrate that optimality gaps of these models are less than 0.3% of the optimal policy cost and computational times are reasonable. (C) 2018 Elsevier B.V. All rights reserved.
Citation - WoS: 13
Citation - Scopus: 13
Deep Learning Method for Compressive Strength Prediction for Lightweight Concrete
(Techno-press, 2023) Nanehkaran, Yaser A.; Azarafza, Mohammad; Pusatli, Tolga; Bonab, Masoud Hajialilue; Irani, Arash Esmatkhah; Kouhdarag, Mehdi; Derakhshani, Reza
Concrete is the most widely used building material, with various types including high-and ultra-high-strength, reinforced, normal, and lightweight concretes. However, accurately predicting concrete properties is challenging due to the geotechnical design code's requirement for specific characteristics. To overcome this issue, researchers have turned to new technologies like machine learning to develop proper methodologies for concrete specification. In this study, we propose a highly accurate deep learning-based predictive model to investigate the compressive strength (UCS) of lightweight concrete with natural aggregates (pumice). Our model was implemented on a database containing 249 experimental records and revealed that water, cement, water-cement ratio, fine-coarse aggregate, aggregate substitution rate, fine aggregate replacement, and superplasticizer are the most influential covariates on UCS. To validate our model, we trained and tested it on random subsets of the database, and its performance was evaluated using a confusion matrix and receiver operating characteristic (ROC) overall accuracy. The proposed model was compared with widely known machine learning methods such as MLP, SVM, and DT classifiers to assess its capability. In addition, the model was tested on 25 laboratory UCS tests to evaluate its predictability. Our findings showed that the proposed model achieved the highest accuracy (accuracy=0.97, precision=0.97) and the lowest error rate with a high learning rate (R2=0.914), as confirmed by ROC (AUC=0.971), which is higher than other classifiers. Therefore, the proposed method demonstrates a high level of performance and capability for UCS predictions.
Citation - WoS: 97
Citation - Scopus: 119
The Degree of Financial Liberalization and Aggregated Stock-Return Volatility in Emerging Markets
(Elsevier Science Bv, 2010) Akdeniz, Levent; Altay-Salih, Aslihan; Umutlu, Mehmet
In this study, we address whether the degree of financial liberalization affects the aggregated total volatility of stock returns by considering the time-varying nature of financial liberalization. We also explore channels through which the degree of financial liberalization impacts aggregated total volatility. We document a negative relation to the degree of financial liberalization after controlling for size, liquidity, country. and crisis effects, especially for small and medium-sized markets. Moreover, the degree of financial liberalization transmits its negative impact on aggregated total volatility through aggregated idiosyncratic and local volatilities. Overall, our results provide evidence in favor of the view that the broadening of the investor base due to the increasing degree of financial liberalization causes a reduction in the total volatility of stock returns. (C) 2009 Elsevier B.V. All rights reserved.
Citation - WoS: 69
Citation - Scopus: 85
Detecting Stock-Price Manipulation in an Emerging Market: the Case of Turkey
(Pergamon-elsevier Science Ltd, 2009) Ogut, Hulisi; Doganay, M. Mete; Aktas, Ramazan
This paper aims to develop methods that are capable of detecting manipulation in the Istanbul Stock Exchange. We take the difference between manipulated stock's and index's average daily return, average daily change in trading volume and average daily volatility and used these statistics as explanatory variables. The data in post-manipulation and pre-manipulation periods are used as non-manipulated instances while the data in the manipulation period are used as manipulated instances. Test performance of classification accuracy, sensitivity and specificity statistics for Artificial Neural Networks (ANN) and Support Vector Machine (SVM) are compared with the results of discriminant analysis and logistics regression (logit). We found that the data mining techniques (ANN and SVM) are better suited to detect stock-price manipulation than multivariate statistical techniques (discriminant analysis, logistics regression) as the performances of the data mining techniques in terms of total classification accuracy and sensitivity statistics are better than those of multivariate techniques. We also found that unit change in difference between average daily return of manipulated stock and the index has the largest effect while unit change in difference between average daily change in trading volume of manipulated stock and index has the least effect on multivariate classifiers' decision functions. (C) 2009 Elsevier Ltd. All rights reserved.
Citation - WoS: 9
Citation - Scopus: 7
The Effects of Federal Regulations on Corruption in Us States
(Elsevier Science inc, 2020) Gunalp, Burak; Dincer, Oguzhan
Using the newly constructed Federal Regulation and State Enterprise Index (FRASE Index) to measure the federal regulations and the existing Corruption Convictions Index (CCI), we investigate the effects of federal regulations on corruption in U.S. states. Controlling for several demographic and economic variables including the Fraser Institute's Economic Freedom Index (EFI), which measures the size and scope of government in U.S. states, we find a positive and statistically significant relationship between federal regulations and corruption. Our findings have important policy implications. A 1 standard deviation increase in FRASE Index causes CCI to increase by approximately 0.5 standard deviations. Standardized coefficient of EFI is also approximately equal to 0.5. In other words, it is possible to mitigate the effects of regulations at the federal level by reducing the size and the scope of the government at the state level.
Citation - WoS: 5
Citation - Scopus: 6
Elliott Wave Principle and the Corresponding Fractional Brownian Motion in Stock Markets: Evidence From Nikkei 225 Index
(Pergamon-elsevier Science Ltd, 2016) Ilalan, Deniz
This paper examines one of the vital technical analysis indicators known as the Elliott wave principle. Since these waves have a fractal nature with patterns that are not exact, we first determine the dimension of them. Our second aim is to find a linkage between Elliott wave principle and fractional Brownian motion via comparing their Hausdorff dimensions. Thirdly, we consider the Nikkei 225 index during Japan asset price bubble, which is a perfect example of an Elliott wave. (C) 2016 Elsevier Ltd. All rights reserved.
Citation - Scopus: 2
Empire of Languages: Eu's Multilingualism Policy and the Turkish Language
(Routledge Journals, Taylor & Francis Ltd, 2012) Atac, C. Akca
Despite its crucial role in sustaining better integration, multilingualism is not discussed as widely as the other topics of multiculturalism within the context of the European Union (EU) enlargement. The accession process requires Turkey to take notice of the opportunities and shortcomings as well as the challenges of European multilingualism and to communicate the relevance of the Turkish language to the completeness of European multiculturalism. The present article aims to assess the EU language policy in light of the future imperative of incorporating Turkish into Europe's linguistic family by referring to the EU's laws, norms, and values as well as NGOs' reports and opinion papers.
Citation - WoS: 22
Citation - Scopus: 26
An Empirical Analysis of Household Education Expenditures in Turkey
(Pergamon-elsevier Science Ltd, 2016) Cilasun, Seyit Mumin; Acar, Elif Oznur; Gunalp, Burak
Using Turkish Household Budget Surveys from 2003, 2007 and 2012, this paper investigates the determinants of household education expenditures within an Engel curve framework. In particular, we estimate Tobit regressions of real educational expenditures by income groups using a number of household characteristics (i.e. rural residence, employment status, age, educational attainment of the household head, household size, share of female students and primary school students in the household, and total number of students in the household) to examine if and to what extent the determinants of educational expenditures differ by income groups; income elasticities of educational spending evolves over time; and children from middle-class and poor families can benefit enough from educational opportunities. The estimated expenditure elasticities have lower values for the top- and the bottom income quartiles while they have larger values for the middle-income quartiles. The results also show that for all income groups the expenditure elasticity of education increases over time, indicating that Turkish households allocates greater share of their budgets to education expenditures. (C) 2016 Elsevier Ltd. All rights reserved.
Citation - WoS: 16
Citation - Scopus: 18
An Empirical Examination of the Generalized Fisher Effect Using Cross-Sectional Correlation Robust Tests for Panel Cointegration
(Elsevier Science Bv, 2015) Yuksel, Aydin; Omay, Tolga; Yuksel, Asli
This study examines the generalized Fisher hypothesis as applied to common stocks by using the recently proposed second generation panel cointegration tests. Unlike their predecessors, these new tests assume the existence of cross-section dependence in the data. For the sample analyzed, we report that these new tests, but not their predecessors, provide strong support for the existence of cointegration between stock and goods prices. Moreover, further analysis cannot reject the hypothesis that the cointegration relation is linear. Finally, our Fisher coefficient estimates are in the range between 0.68 and 1.27 and give support to the generalized Fisher hypothesis. (C) 2014 Elsevier B.V. All rights reserved.
Citation - WoS: 30
Citation - Scopus: 33
Employee Deviant Behavior: Role of Culture and Organizational Relevant Support
(Emerald Group Publishing Ltd, 2019) Kalemci, R. Arzu; Kalemci-Tuzun, Ipek; Ozkan-Canbolat, Ela
Purpose The purpose of this paper is to increase the knowledge and understanding of organizational and supervisory support in the context of employee deviant workplace behavior (DWB) by examining the potential associations of employees' cultural value orientations. This paper aims to: clarify DWB; review perceived organizational support (POS) and perceived supervisory support (PSS); discuss the meaning of employees' cultural value orientations (individualism-collectivism, power distance and paternalism); use the fuzzy logic model to analyze relationships between DWB and POS, as well as PSS and employees' cultural value orientations. Design/methodology/approach This research applies a fuzzy-set qualitative comparative analysis. Findings The results show the role of employee perceived organizational and supervisory support and cultural dimension (power distance and paternalism) configurations on employee DWB. Originality/value The main originality of this study is to further increase the understanding of organizational and supervisory support in the context of employee DWB by examining the potential associations of employees' cultural value orientations. This study extends the previous research by providing evidence that organizational and supervisory support influences employees' DWB.
Citation - WoS: 4
Citation - Scopus: 4
Estimation in Multivariate Nonnormal Distributions With Stochastic Variance Function
(Elsevier Science Bv, 2014) Islam, M. Qamarul
In this paper the problem of estimation of location and scatter of multivariate nonnormal distributions is considered. Estimators are derived under a maximum likelihood setup by expressing the non-linear likelihood equations in the linear form. The resulting estimators are analytical expressions in terms of sample values and, hence, are easily computable and can also be manipulated analytically. These estimators are found to be remarkably more efficient and robust as compared to the least square estimators. They also provide more powerful tests in testing various relevant statistical hypotheses. (C) 2013 Elsevier B.V. All rights reserved.
Citation - WoS: 65
Citation - Scopus: 82
Fdi Inflow as an International Business Operation by Mncs and Economic Growth: an Empirical Study on Turkey
(Elsevier Science Bv, 2014) Temiz, Dilek; Gokmen, Aytac
The issue of foreign direct investment (FDI) has been affecting the world economy for years and is a considerable subject for both developed and developing countries. FDI is the fixed form of international business operation made across the national borders made mostly by the multi national corporations (MNCs). The positive impact of FDI inflow in a host country is expected to emerge as capital accumulation, technology transfer, know-how acquisition, innovative capacity and economic growth eventually. In this study, it is aimed to address the FDI literature depending on comprehensive international publications and then to analyze the FDI inflow and GDP growth in Turkey with econometric methods. The relation between FDI inflow and GDP growth is analyzed by using the Johansen cointegration test and Granger causality analysis. Afterwards, a regression equation is estimated by using the ordinary least squares method (OLS). Prior to applying the Cointegration test, the stationarity and integration degrees of the series are determined by the augmented Dickey-Fuller test (ADF). Consequently, resting on the results of entire analysis, it is possible to mention that no significant relation is determined between the FDI inflow and GDP growth in Turkey both in the short and long run. (C) 2013 Elsevier Ltd. All rights reserved.
Citation - WoS: 13
Citation - Scopus: 13
A Glance at the Constitutive Elements of the Leader-Centered Perspective in Turkish Politics
(Routledge Journals, Taylor & Francis Ltd, 2017) Turk, H. Bahadir
Leadership is a major aspect of Turkish politics; leaders in Turkish politics are regarded as either almost sacred figures or the ultimate reason for all political, social and economic problems. Leaders are seen as decision makers who have a significant impact on almost all aspects of life. It can be contended that a historical continuance toward the leader-centered perspective is present in Turkish politics. This paper aims to present a descriptive framework outlining the elements that constitute the leader-centered perspective in Turkish politics. To accomplish this goal, the paper presents two major arguments. It is argued that the constitutive elements of the leader-centered perspective in Turkish politics are a sui generis synthesis of patrimonialism, patriarchy, populism and militarism. Furthermore, this fourfold historical structure strengthens forms of charismatic leadership and can provide insight into the central role of leadership in Turkish politics.
Citation - WoS: 4
Citation - Scopus: 4
Hegemonic Masculinity and Terrorism: the Case of the Pkk and Abdullah Ocalan
(Taylor & Francis Ltd, 2020) Turk, H. Bahadir
Recent years have seen an increase in the study of the relationship between gender and terrorism. This article analyzes the relationship between hegemonic masculinity and terrorism through the case of the Kurdistan Workers' Party (Partiya Karkeren Kurdistan or PKK) and its leader Abdullah ocalan. Using the method of narrative analysis, the study first examines the concept of hegemonic masculinity. The study attempts to make sense of how the concept of hegemonic masculinity operates within the PKK. To achieve this goal, the study demonstrates the major functions of hegemonic masculinity within terrorist organisations. Accordingly, it is argued that the perspective of masculinity studies can be used to gain a better and highly instructive understanding of political violence and terrorism.
Citation - WoS: 21
Citation - Scopus: 24
Heuristic Policies for the Stochastic Economic Lot Sizing Problem With Remanufacturing Under Service Level Constraints
(Elsevier Science Bv, 2018) Kilic, Onur A.; Tunc, Huseyin; Tarim, S. Armagan
In this paper, we address the stochastic economic lot sizing problem with remanufacturing under service level constraints. The problem emerges in hybrid production systems where demand can be met via two alternative sources: manufacturing new products and remanufacturing returned products. The deterministic counterpart of this problem has been considered in the literature and it is shown to be NP-Hard. We focus on the case where period demands and returns are stochastic. The optimal solution to this problem is not a deterministic production schedule but a control policy, yet its structure has not yet been characterized. We propose two heuristic policies for the problem that make use of simple decision rules to control manufacturing and remanufacturing operations and present mathematical models thereof. (C) 2018 Elsevier B.V. All rights reserved.
Citation - WoS: 3
Citation - Scopus: 4
High Persistence and Nonlinear Behavior in Financial Variables: a More Powerful Unit Root Testing in the Estar Framework
(Mdpi, 2021) Corakci, Aysegul; Hasdemir, Esra; Omay, Tolga
In this study, we consider the hybrid nonlinear features of the Exponential Smooth Transition Autoregressive-Fractional Fourier Function (ESTAR-FFF) form unit root test. As is well known, when developing a unit root test for the ESTAR model, linearization is performed by the Taylor approximation, and thereby the nuisance parameter problem is eliminated. Although this linearization process leads to a certain amount of information loss in the unit root testing equation, it also causes the resulting test to be more accessible and consistent. The method that we propose here contributes to the literature in three important ways. First, it reduces the information loss that arises due to the Taylor expansion. Second, the research to date has tended to misinterpret the Fourier function used with the Kapetanios, Shin and Snell (2003) (KSS) unit root test and considers it to capture multiple smooth transition structural breaks. The simulation studies that we carry out in this study clearly show that the Fourier function only restores the Taylor residuals of the ESTAR type function rather than accounting forthe smooth structural break. Third, the new nonlinear unit root test developed in this paper has very strong power in the highly persistent near unit root environment that the financial data exhibit. The application of the Kapetanios Shin Snell- Fractional Fourier (KSS-FF) test to ex-post real interest rates data of 11 OECD countries for country-specific sample periods shows that the new test catches nonlinear stationarity in many more countries than the KSS test itself.
Citation - WoS: 7
Citation - Scopus: 8
Hysteresis and Stochastic Convergence in Eurozone Unemployment Rates: Evidence From Panel Unit Roots With Smooth Breaks and Asymmetric Dynamics
(inst Badan Gospodarczych, 2022) Omay, Tolga; Hasanov, Mubariz; Corakci, Aysegul
Research background: Studying the dynamic characteristics of unemployment rate is crucial for both economic theory and macroeconomic policies. Despite numerous research, the empirical evidence about stochastic behaviour of the unemployment rate remains disputable. It has been widely agreed that most economic variables, including unemployment rates, are characterized by both structural breaks and nonlinearities. However, a little work is done to examine both features simultaneously. Purpose of the article: In this paper, we analyse the stationarity properties of unemployment rates of Euro area member countries. Also, we aim to test stochastic convergence of unemployment rates among member countries. Our empirical procedures explicitly allow for simultaneous gradual breaks and nonlinearities in the series. Methods: This paper develops a new unit root test procedure for panel data, allowing for both gradual structural breaks and asymmetric adjustment towards equilibrium. We carry out Monte Carlo simulations to examine small sample performance of the proposed test procedure and compare it to the existing test procedures. We apply the newly proposed test to examine the stochastic properties of the unemployment rates of Euro-member countries as well as relative unemployment rates vis-a-vis the Eurozone unemployment rate. Findings & value added: We find that the newly developed test procedure outperforms existing tests in highly nonlinear settings. Also, these tests reject the null hypothesis of unit root in more cases when compared to the existing tests. We find stationarity in the series only after allowing for structural breaks in the data generating process. Allowing for nonlinear and asymmetric adjustment in addition to gradual breaks provides evidence of stationarity in more cases. Furthermore, our results suggest that relative unemployment rate series are stationary, providing evidence in favour of stochastic convergence in unemployment rates. Overall, our results imply a limited room for coordinated economic policy to fight unemployment in the Eurozone.
Citation - WoS: 19
Citation - Scopus: 24
Increasing Accuracy of Two-Class Pattern Recognition With Enhanced Fuzzy Functions
(Pergamon-elsevier Science Ltd, 2009) Tuerksen, I. Burhan; Aktas, Ramazan; Doganay, M. Mete; Ceylan, N. Basak; Celikyilmaz, Asli
In building an approximate fuzzy classifier system, significant effort is laid oil estimation and fine tuning of fuzzy sets. However, in such systems little thought is given to the way in which membership functions are combined within fuzzy rules. In this paper, a robust method, improved fuzzy classifier functions (IFCF) design is proposed for two-class pattern recognition problems. A supervised hybrid improved fuzzy Clustering for classification (IFC-C) algorithm is implemented for structure identification. IFC-C algorithm is based oil it dual optimization method, which yields simultaneous estimates of the parameters of (c-classification functions together with fuzzy c partitioning of dataset based oil a distance measure. The merit of novel IFCF is that the information oil natural grouping of data samples i.e., the membership values, are utilized as additional predictors of each fuzzy classifier function to improve accuracy of system model. Improved fuzzy classifier functions are approximated using statistical and soft computing approaches. A new semi-non-parametric inference mechanism is implemented for reasoning. The experimental results Of the new modeling approach indicate that the new IFCF is it promising method for two-class pattern recognition problems. (c) 2007 Elsevier Ltd. All rights reserved.

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