İktisadi ve İdari Bilimler Fakültesi

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Citation - WoS: 1
Citation - Scopus: 2
A new causal discovery heuristic
(Springer, 2018) Prestwich, S. D.; Özkan, İbrahim; Tarim, S. A.; Ozkan, I.; 6641; 169580; Yönetim Bilişim Sistemleri
Probabilistic methods for causal discovery are based on the detection of patterns of correlation between variables. They are based on statistical theory and have revolutionised the study of causality. However, when correlation itself is unreliable, so are probabilistic methods: unusual data can lead to spurious causal links, while nonmonotonic functional relationships between variables can prevent the detection of causal links. We describe a new heuristic method for inferring causality between two continuous variables, based on randomness and unimodality tests and making few assumptions about the data. We evaluate the method against probabilistic and additive noise algorithms on real and artificial datasets, and show that it performs competitively.
Citation - WoS: 19
Citation - Scopus: 20
An Extended Mixed-Integer Programming Formulation and Dynamic Cut Generation Approach for the Stochastic Lot-Sizing Problem
(informs, 2018) Tunc, Huseyin; Kilic, Onur A.; Tarim, S. Armagan; Rossi, Roberto; 6641
We present an extended mixed-integer programming formulation of the stochastic lot-sizing problem for the static-dynamic uncertainty strategy. The proposed formulation is significantly more time efficient as compared to existing formulations in the literature and it can handle variants of the stochastic lot-sizing problem characterized by penalty costs and service level constraints, as well as backorders and lost sales. Also, besides being capable of working with a predefined piecewise linear approximation of the cost function-as is the case in earlier formulations-it has the functionality of finding an optimal cost solution with an arbitrary level of precision by means of a novel dynamic cut generation approach.
Citation - WoS: 7
Citation - Scopus: 5
Distinct Asymmetric Effects of Military Spending on Economic Growth for Different Income Groups of Countries
(Taylor & Francis Ltd, 2023) Karadam, Duygu Yolcu; Öcal, Nadir; Ocal, Nadir; Yildirim, Julide; 163521; İktisat
Although possible asymmetries for univariate and multivariate dynamics have been the focus of interest in many areas of economic explorations, it seems that most of the research on military expenditure - economic growth nexus has tended to assume linear relationships. This paper aims to examine possible nonlinearities in military expenditure-economic growth nexus employing data for a sample of 103 countries covering the 1988-2019 period. For this purpose, Panel Smooth Transition Regression, PSTR, models are estimated not only for all countries' sample but also for low income, middle income, and high-income countries' subsamples to reveal possible distinct asymmetric relationships for country groups with different income levels. Empirical results for the whole sample, low income and middle income groups indicate that military expenditure not only governs the regime change, but also low and high levels of military expenditure have distinctive and rising negative effects on economic growth with dissimilar threshold effects. Moreover, empirical findings also indicate that net arms exports govern regime change for high income countries, and as net arms exports rise, the negative impacts of military expenditure on economic growth become deeper.
Citation - WoS: 4
Citation - Scopus: 5
Does workplace envy always have detrimental consequences in organizations? A study of public and private sector employees
(Emerald Group Publishing Ltd, 2022) Sener, Irge; Şener, İrge; Karabay, Melisa Erdilek; Elci, Meral; Erman, Halil; 21583; İşletme
Purpose Based on the situational approach for envy, the purpose of this paper is to examine the effect of two-dimensional workplace envy (being envied and envying others) on the task and contextual performance of employees working in either private or public sector organizations. Design/methodology/approach This study was conducted on survey data collected from 988 private sector employees and 530 employees from the public sector employed in Istanbul. Following a quantitative empirical design, structural equation modeling was used to test the hypotheses. Findings The study results revealed that envying-others dimension has a significant negative effect on both task performance and contextual performance. In addition, the findings indicate more envious feelings of private sector employees than public sector employees. For public sector employees, male participants were found to envy others more than females. Research limitations/implications In addition to the contributions, this study has its limitations. First, although the study was carried out with a comprehensive sample, it is limited to the views of 1,518 employees in Istanbul and is a cross-sectional study. Also, employee performance is evaluated through self-reporting, which forms another limitation; it could have been more reliable for the supervisors to assess their subordinates' performance. Practical implications Apart from scholars, our findings have implications for practitioners. Feelings such as envy that comes with a sense of competition can create an environment that stimulates people, motivates them to work, can make them productive and can also cause an ultimately destructive situation. This makes it critical to manage envy in the workplace. Though there may be facilitators behind it, one crucial factor that fuels envy in the workplace is the lack of fair human resources policies and systems. Still, human resources management is undeveloped in most public organizations. With effective human resources management, there may be some roadmaps for managers to dissolve conflicts arising from envy. First, it is imperative to have systems that will separate the employee from the others, which everyone will accept, strengthening the feelings of justice among employees. Envy often occurs following a social comparison. Management can implement an incentive system that supports employee collaboration and avoid nepotism. Especially in private organizations where the competition is more among employees, managers should give more attention to understand their subordinates' feelings. The managers' attention to expressing their feelings toward their subordinates could establish an equal distance within the workplace. In this sense, language selection is critical, and managers should be mindful of linguistic triggers. Managers should not avoid giving both positive and negative feedback to their employees. Unwarranted and unsystematic reward and/or punishment systems, made with the good intentions of increasing competition, can trigger envy. Finally, managers should implement an open-door policy and open communication that will encourage all team members to be transparent to each other. Originality/value The study was based on a rationale that envy has detrimental workplace outcomes that lead to low task and contextual performance. Although there exists a recent interest for examining the relation between workplace envy and employee performance, based on being envied and envying others dimensions, these studies are limited. This study focuses on these dimensions and performance relations, and it also provides a comparative outlook for public and private sector employees in Turkey in terms of workplace envy.
Citation - WoS: 10
Citation - Scopus: 10
ENERGY CONSUMPTION AND GROWTH: NEW EVIDENCE FROM A NON-LINEAR PANEL AND A SAMPLE OF DEVELOPING COUNTRIES
(World Scientific Publ Co Pte Ltd, 2015) Omay, Tolga; Omay, Tolga; Apergis, Nicholas; Ozcelebi, Hulya; Çankaya Meslek Yüksekokulu
This paper investigates the relationship between economic growth and energy consumption through non-linear causality tests. Eight developing countries from Europe and Central Asia spanning the period 1993 to 2008 are selected for the purpose of panel empirical analysis. Panel unit root and panel cointegration tests with and without considering cross section dependency (CD) problems are implemented. Next, linear panel cointegration tests are employed and, finally, a two-regime Dynamic Panel Smooth Transition Vector Error Correction (PSTRVEC) model is estimated for testing the presence of non-linear short-and long-run causality. To this end, a new estimator, called the Dynamic Non-linear Pooled Common Correlated Effect Estimator (DNPCCEE) is proposed. The empirical findings indicate that short and long-run causalities are regime-dependent.
Citation - WoS: 12
Citation - Scopus: 16
Exchange rate risk and international trade: The role of third country effect
(Elsevier Science Sa, 2018) Tunc, Cengiz; Solakoglu, M. Nihat; Babuscu, Senol; Hazar, Adalet; 265921; 161529; 117425; 219046
Using the recently launched Exporter Dynamics Database of the World Bank, this paper empirically investigates the role of external exchange rate risk (third-country effect) on trade flows between countries. We find a strong positive influence of external exchange rate risk on exports to a specific destination. However, the effect is more observable in advanced destination countries, countries with low bilateral exchange rate volatility in comparison to external exchange rate volatility, and countries in which export is concentrated among a small number of firms. (C)2018 Elsevier B.V. All rights reserved.
Citation - WoS: 4
Citation - Scopus: 3
Fixed Point Results Via Simulation Functions in the Context of Quasi-Metric Space
(Univ Nis, Fac Sci Math, 2018) Fulga, Andreea; Tas, Aysegul; 29252
In this paper, we investigate the existing non-unique fixed points of certain mappings, via simulation functions in the context of quasi-metric space. Our main results generalize and unify several existing results on the topic in the literature.
Citation - Scopus: 21
Forecasting stock market volatility: Further international evidence
(2006) Balaban, E.; Bayar, A.; Faff, R.W.
This paper evaluates the out-of-sample forecasting accuracy of eleven models for monthly volatility in fifteen stock markets. Volatility is defined as within-month standard deviation of continuously compounded daily returns on the stock market index of each country for the ten-year period 1988 to 1997. The first half of the sample is retained for the estimation of parameters while the second half is for the forecast period. The following models are employed: a random walk model, a historical mean model, moving average models, weighted moving average models, exponentially weighted moving average models, an exponential smoothing model, a regression model, an ARCH model, a GARCH model, a GJR-GARCH model, and an EGARCH model. First, standard (symmetric) loss functions are used to evaluate the performance of the competing models: mean absolute error, root mean squared error, and mean absolute percentage error. According to all of these standard loss functions, the exponential smoothing model provides superior forecasts of volatility. On the other hand, ARCH-based models generally prove to be the worst forecasting models. Asymmetric loss functions are employed to penalize under-/over-prediction. When under-predictions are penalized more heavily, ARCH-type models provide the best forecasts while the random walk is worst. However, when over-predictions of volatility are penalized more heavily, the exponential smoothing model performs best while the ARCH-type models are now universally found to be inferior forecasters.
Citation - WoS: 88
Citation - Scopus: 82
Fractional frequency flexible fourier form to approximate smoothbreaks in unit root testing
(Elsevier Science Sa, 2015) Omay, Tolga; Omay, Tolga; 19320; Çankaya Meslek Yüksekokulu
In this study, a Fractional Frequency Flexible Fourier Form DF-type unit root test is proposed. The small sample properties of the proposed test are found to be better than that of the integer frequency counterpart. (C) 2015 Elsevier B.V. All rights reserved.
Citation - WoS: 32
Citation - Scopus: 31
Lessons of military regimes and democracy: The Turkish case in a comparative perspective
(Sage Publications inc, 2005) Demirel, T; Demirel, Tanel; 4812; Siyaset Bilimi ve Uluslararası İlişkiler
How the nature of an outgoing authoritarian regime affects the advent of a new democracy continues to be a matter of controversy. One line of argument states that in countries which experience repressive and discredited authoritarian regimes, political actors have come to better appreciate the virtues of democracy.(1) It is presumed that gross human-rights violations, widespread state-sponsored terror, and consequent fear and insecurity under military rule might result in attitudinal changes that favor democracy. Those who criticize the democratic regime for a slow decision-making process, or for failing to improve socioeconomic inequalities, for instance, might better understand the difference between military rule and democracy in terms of the protection of basic human rights. Similarly, disappointments caused by the military regimes in the economic and/or military spheres could shatter myths about the effectiveness of military rule or authoritarian decision-making processes. It might become clear, for instance, that the army's combat effectiveness is severely damaged under military dictatorships, or that military officers at the top might be as divided, inefficient, or corrupt as civilian politicians. Such value change, it is further assumed, helps the new democratic regime to withstand considerable strains because the alternative-authoritarian regression-is perceived to be even worse.(2) While not contradicting the idea that a repressive and/or discredited authoritarian regime might lead to a positive view of democracy, other scholars do not consider this factor as very significant. Juan Linz and Alfred Stephan, for instance, argued that the positive attitude toward democracy "as the best alternative for now and for the future, does not require a negative attitude toward the past."(3) Neither in cases of established democracies nor in recent transitions to democracy, they claim, can one find any strong evidence that rejection of the authoritarian past had taken place. Positive assessment of the past regime is not an obstacle to securing the loyalty of citizens to the democratic regime; one can prefer the democratic regime while also believing that an authoritarian regime had its own achievements. In the same vein, emphasizing new incentive structures that came into existence during the transition process as the most important variable affecting behavior of the elites, authors such as Guiseppe Di Palma and Adam Przeworski also came to similar conclusions.(4) This article highlights the point that the nature of an outgoing authoritarian regime has a significant impact on a new democracy. It attempts to do so through discussion of the Turkish case. Turkey's long experience with constitutional and representative government stretches back to the nineteenth century. It has maintained a more-or-less democratic system of government since its first transition to democracy in 1946, despite three military interventions (in 1960, 1971, and 1980). The complex interactions of various factors have helped the Turkish military to protect itself from the damaging consequences associated with military rule. The military interludes in Turkey (1960-61, 1971-73, 1980-83) have hardly been seen by a significant number of civilians as highly repressive, nor have they been conceived as failures in political, economic, or military terms. In all formal transitions, the military has hardly been compelled to exit from power. The thesis advanced here is that this particular experience of a military regime, of authoritarian interludes, has to be taken into account to understand the trials and tribulations of Turkish democracy. The positive evaluation of military rule was one reason why the political actors have found it difficult to regard a democratic regime as "the only game in town."(5) In other words, the Turkish experience has given rise to a conviction that the costs of abandoning democracy are not so high; therefore, in some cases, the military regime might be acceptable. This presumption has, in turn, weakened the civilian resolve to seek remedies within the democratic system. The military regime seemed to offer quick, clear-cut, and less costly solutions. The problem-solving capacity consideration that they might avoid the worst of what the others experienced, the idea that "it will not happen here," appears to have worked as a hindrance for learning in many settings. Few opponents of Allende who looked forward favorably to a military coup were able to foresee that a repressive regime was on its way given Chile's rather noninterventionist military tradition.(71) Civilians invoking a dictatorship generally consider that they might manipulate it, or minimize the possible costs. For these reasons, it would be misleading to talk about political learning as a spontaneous and natural process, or to condemn actors for failing to learn due largely to selfish short-sightedness or individual traits. One should also stress that some perceptions of military rule are the result of careful construction. Those who value democracy should not fail to recall the painful memories of the past; on the other hand, it would be inappropriate to attribute undue weight to an artful deception. If the real experience of the people has not made them receptive to recalling such collective memories, the whole effort might be destined to remain futile. A brief examination of military regimes and their impact on a change of values shows how complex the issues are, and how difficult it is to make straightforward inferences. A recognition of this complexity, however, does not change the fact that political learning, either through interaction or comparison, is critical for sustaining democracy.
Citation - WoS: 11
Citation - Scopus: 10
Managing working capital efficiency in Turkish agribusinesses and the impact of globalization: insights from an emerging market
(Wageningen Academic Publishers, 2019) Akdogan, Ece C.; Akdoğan, Ece Ceylan; Dinc, Dilek Temiz; 52039; Bankacılık ve Finans
The efficiency of working capital is a major determinant of firm profitability. So, the grasp of working capital dynamics is extremely important for managers, but also for policy makers, since inefficient working capital management is an important source of industrial sickness. This study focuses on the profitability impacts of working capital policies of Turkish agribusinesses, and aims to investigate the potential effects of globalization on these interrelated relationships. The findings obtained from pooled panel analyses demonstrate that Turkish agribusinesses can enhance their profitability and value by adopting a conservative working capital policy through lengthening the cash conversion cycle up to an optimal level. Besides, globalization is found to deteriorate their efficiency and profitability where economic globalization seems to have the highest impact raising questions on the effectiveness of Turkish agribusinesses in coping with competition. Thus, both the managers and the policy makers should concern with the competitiveness impacts of globalization.
Citation - WoS: 2
Citation - Scopus: 2
On the heterogeneous effects of tax policy on labor market outcomes
(Wiley, 2022) Adnan, Wifag; Arin, Kerim Peren; Corakci, Aysegul; Spagnolo, Nicola; 103299
Many recent studies have documented the heterogeneous effects of government-spending shocks on major macroeconomic variables, particularly on output. We delve deeper into the heterogeneous effects of fiscal policy innovations, but focus on the tax policy innovations and their impact on the labor market, while accounting for gender, race, ethnicity, and the business cycle. Using microlevel data from the United States, we find that: (i) Tax shocks have varying employment effects depending on gender, race, and the stage of the business cycle; (ii) Sector, industry, and occupational segregation in labor markets by gender, race, and ethnicity can explain most of the variation in response to fiscal policy shocks.
Citation - WoS: 21
Citation - Scopus: 20
Re-examining the real interest rate parity hypothesis (RIPH) using panel unit root tests with asymmetry and cross-section dependence
(Springer, 2017) Corakei, Aysegul; Omay, Tolga; Emirmahmutoglu, Furkan; Omay, Tolga; 103299; Çankaya Meslek Yüksekokulu
This paper investigates the validity of the real interest rate parity hypothesis (RIPH) using a panel unit root approach. For this purpose, first we estimate the possible nonlinear data-generating processes of the real interest rate differential series and using these estimates determine which panel unit root test is better for analyzing the RIPH. To this end, smooth transition autoregressive and threshold autoregressive (TAR) models are estimated for two different panels of countries: G7 and post-Soviet transition economies. The results show that the data displays both strong asymmetry and high transition speed. Therefore, secondly, we propose a new panel unit root test where the alternative is stationary with asymmetric TAR adjustment, and provide their empirical power properties. Finally, we demonstrate that our newly proposed test is able to provide conclusive evidence in favor of the RIPH in contrast to the other panel unit root tests considered.
Citation - WoS: 2
Citation - Scopus: 3
Renegotiations of femininity throughout the constitutional debates in Turkey: representative claims in 2014 presidential elections
(Routledge Journals, Taylor & Francis Ltd, 2018) Yaras, Sezen; Yigit, Ahu
In August 2014, for the first time in the history of the Turkish Republic, the president was elected through a popular vote. The quest for a new constitution and revisions to the political system were the main topics that the three presidential candidates, Recep Tayyip Erdogan, Ekmeleddin Ihsanoglu and Selahattin Demirtas, raised during their presidential campaigns. Women's problems and issues were among the central topics through which the matters of the new constitution and the revisions to be made in the system were addressed. Through a qualitative content analysis of the campaign material, this article maps the candidates' approaches to women's interests and the roles the candidates promised to play to promote these interests and roles. The findings indicate that motherhood, daughterhood and sisterhood are the key terms through which the candidates formulated the ultimate purpose of their gender-related agenda. They simply blamed the existing constitution as the main cause of alienated motherhood, polarized daughterhood and complicit femininity respectively. Based on the analysis of these simultaneous calls for heightening-disavowal of certain femininities, the article argues that competing projects for the (re)establishment of the constitutional regime in Turkey can be construed as renegotiations of feminine attachments to political authority.
Citation - WoS: 9
Citation - Scopus: 15
Stock returns and volatility: empirical evidence from fourteen countries
(Routledge Journals, Taylor & Francis Ltd, 2005) Balaban, E; Bayar, A
This is a pioneering effort to test in 14 countries the relationship between stock market returns and their forecast volatility derived from the symmetric and asymmetric conditional heteroscedasticity models. Both weekly and monthly returns and their volatility are investigated. An out-of-sample testing methodology is employed using volatility forecasts instead of investigating the relation between stock returns and their in-sample volatility estimates. Expected volatility is derived from the ARCH(p), GARCH(1, 1), GJR-GARCH(1, 1) and EGARCH(1, 1) forecast models. Expected volatility is found to have a significant negative or positive effect on country returns in a few cases. Unexpected volatility has a negative effect on weekly stock returns in six to seven countries and on monthly returns in nine to eleven countries depending on the volatility forecasting model. However, it has a positive effect on weekly and monthly returns in none of the countries investigated. It is concluded that the return variance may not be an appropriate measure of risk.
Citation - WoS: 4
Citation - Scopus: 5
Tackling service quality in the telecommunication B2B market
(Emerald Group Publishing Ltd, 2019) Tas, Aysegul; Ergin, Elif Akagun; Kurtulmusoglu, Feride Bahar; Sahin, Omer Faruk; 29252; 120408
Purpose This study will attempt to focus on how vendors serve operators, as operator service quality starts with vendor's technology infrastructure and service quality. The purpose of this study is to exhibit the most important vendor service quality items and dimensions for the operators in the telecommunications industry. Design/methodology/approach A total of 268 employees from various age groups, cities, job levels and departments participated in the survey. Findings Expected service quality results indicated that operators need high service quality. When telecommunication needs of subscribers are taken into account, it is normal for operators to expect high service quality from vendors. Results also reveal that being dependable and providing continuous support are critical for the telecommunications industry. Perceived service quality results demonstrate that customer expectations failed to be satisfied. In this study conducted in the telecommunications market, the expectations of operator employees regarding vendors is shaped under two dimensions. These dimensions are employee and service center features and provider timeliness and accuracy. When Topsis method was used to determine the most important vendor characteristics, timeliness and trust were identified as the top two criteria. Originality/value To the best of the authors' knowledge, this study is the first to put forth the most important vendor service quality items and dimensions for the operators in the telecommunications industry.
Citation - WoS: 7
Citation - Scopus: 8
The importance and impact of fossil and renewable energy sources in Turkey on business and the economy
(Taylor & Francis inc, 2015) Temiz, Dilek; Gokmen, A.; Temiz, D.; Gökmen, Aytaç; 17660; 52039; Uluslararası Ticaret ve Finansman
Turkey is rapidly growing in terms of both its economy and its population. In parallel, its demand for energy is increasing fast. Energy is one of Turkey's most important development priorities. Today, Turkey's economy is mainly dependent on oil, natural gas, coal, and electricity. Turkey's energy production meets only a part of its total energy consumption and thereby is an energy-importing country. On the other hand, Turkey has a large potential for renewable energies. The most important renewable sources for Turkey's energy sector are wind, biomass, hydro, solar and geothermal. Renewable energy sources respond to the process of the trio of energy, economy, and environment because, as a local source it has many positive effects on employment and provides momentum to the economy of the country. Turkey would have to commit to the development and implementation of renewable energy technologies and energy conservation. The implementation of renewable energy technologies would reduce the current national and global environmental problems as well as national energy insecurity associated with the production and use of fossil energies. Thus, the aim of this article is to present the energy situation and potential of the renewable energy sources in Turkey as well as associate these factors with the economy and business priorities.
Citation - WoS: 11
Citation - Scopus: 15
The mediating role of trust in leader in the relations of ethical leadership and distributive justice on internal whistleblowing: a study on Turkish banking sector
(Emerald Group Publishing Ltd, 2021) Alpkan, Lutfihak; Şener, İrge; Karabay, Melisa; Sener, Irge; Elci, Meral; Yildiz, Bora; 21583; İşletme
Purpose The purpose of this paper is to explain the effect of perceived ethical leadership and perceived distributive justice on internal whistleblowing intention through trust in leader as a mediator. Design/methodology/approach Following an empirical design, data were collected from 1,296 employees of Turkish financial institutions, located in Istanbul. To test four hypotheses structural equation modelling was applied. Findings Results reveal that trust in a leader fully mediates the positive effects of both ethical leadership and distributive justice on the internal whistleblowing intention. Originality/value This study enhances the understanding of the ethical leadership perception and distributive justice affecting the internal whistleblowing intention in Turkey that is a developing country. Although numerous studies on whistleblowing have been conducted, this study's originality and contribution lay in the examination of trust in the leader as a missing link between the direct relations.
Citation - WoS: 34
Citation - Scopus: 33
The Turkish military's decision to intervene: 12 September 1980
(Sage Publications inc, 2003) Demirel, T; Demirel, Tanel; Siyaset Bilimi ve Uluslararası İlişkiler
This article analyzes the Turkish military's decision to take over the government on 12 September 1980. It argues that just because the military believed itself to be a true guardian state, it easily considered intervention a legitimate solution. The perceived threats to the integrity of the Republican state posed by rampant terrorism were the key elements driving soldiers towards intervention. In retrospect, the military's willingness to learn from experience and the role played by civilians in encouraging the military to take over the reins of government are striking features of the whole episode.
Citation - WoS: 4
Citation - Scopus: 9
Turnover, ownership and productivity in Malaysian manufacturing
(Routledge Journals, Taylor & Francis Ltd, 2013) Dogan, Ergun; Wong, Koi Nyen; Yap, Michael M. C.; 43080
Applying Foster, Haltiwanger, and Krizan's decomposition of productivity growth method to Malaysian manufacturing census data for 2000 and 2005, we analyze if firm turnover by ownership (domestic vs. foreign) has any impact on the sector's aggregate productivity growth. The findings show that turnover matters regardless of ownership, but more importantly, attracting foreign direct investment inflows could induce positive net entry effect'. The analysis shows that large-sized foreign and domestic entrants are more productive than medium-sized and especially small-sized ones. The study provides important implications for government policies based on ownership and firm size.

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