Browsing by Subject "Empirical analysis"

Now showing 1 - 15 of 15

Open Access
An analysis of social networks based on tera-scale telecommunication datasets
(IEEE Computer Society, 2019) Aksu, Hidayet; Körpeoğlu, İbrahim; Ulusoy, Özgür
With the popularization of mobile phone usage, telecommunication networks have turned into a socially binding medium. Considering the traces of human communication held inside these networks, telecommunication networks are now able to provide a proxy for human social networks. To study degree characteristics and structural properties in large-scale social networks, we gathered a tera-scale dataset of call detail records that contains ≈ 5 × 10 7 nodes and ≈ 3.6 × 10 10 links for three GSM (mobile) networks, as well as ≈ 1.4 × 10 7 nodes and ≈ 1.9 × 10 9 links for one PSTN (fixed-line) network. In this paper, we first empirically evaluate some statistical models against the degree distribution of the country's call graph and determine that a Pareto log-normal distribution provides the best fit, despite claims in the literature that power-law distribution is the best model. We then question how network operator, size, density, and location affect degree distribution to understand the parameters governing it in social networks. Our empirical analysis indicates that changes in density, operator and location do not show a particular correlation with degree distribution; however, the average degree of social networks is proportional to the logarithm of network size. We also report on the structural properties of the communication network. These novel results are useful for managing and planning communication networks.
Open Access
Asymmetric effects of monetary policy shocks on economic performance: empirical evidence from Turkey
(Routledge, 2016) Ülke, V.; Berument, Hakan
This study investigates the asymmetric effects of monetary policy shocks on the macroeconomic variables of exchange rate, output and inflation for an emerging economy ‒ Turkey ‒ by using monthly data between 1990 and 2014. We employ the innovative nonlinear vector autoregressive model of Kilian and Vigfusson (2011), which allows us to observe the effect of different stances (tight or loose) and different sizes (small or large) of monetary policy actions. Our empirical evidence reveals that tight monetary policy, which, in this case, is captured with a positive shock to interest rate, decreases exchange rate, output and prices, as economic theory suggests. Loose monetary policy, which is captured with a negative shock to interest rate, has the opposite effect on these variables. However, the effects of loose monetary policy are weaker than the effects of tight monetary policy because loose monetary policy shocks are less effective than tight monetary policy shocks. Moreover, as the magnitude of a shock increases, the difference between the effects of tight and loose monetary policy policies also increases. © 2015 Taylor & Francis.
Open Access
Banking activities and local output growth: does distance from centre matter?
(Routledge, 2008) Özyildirim, S.; Önder, Z.
Banking activities and local output growth: does distance from centre matter? Regional Studies. In this paper the relation between local banking activities and local output growth is empirically studied in Turkey during the period 1991-2000. Although there is no legal restriction against regional banking, the banking sector is spatially concentrated in Turkey. In this institutional structure, the distance between headquarters and the local branches is argued to affect the role of financial intermediation in the development of provincial prosperity. Empirical findings suggest that banking activities have a significant positive impact on the per capita local output growth of regions, especially on those that are distant from the financial centre. However, when bank loans are adjusted to the size of the local economy (provincial gross domestic product, GDP), the relation between banking activities and the output per capita is found to be negative, suggesting that these loans are used to finance unprofitable and unproductive projects in distant provinces.
Open Access
Curbing Kurdish ethno-nationalism in Turkey: an empirical assessment of pro-Islamic and socio-economic approaches
(Routledge, 2010) Sarigil, Z.
Within the debates on curbing Kurdish ethno-nationalism in Turkey, the pro-Islamic approach puts emphasis on empowering the notion of 'Islamic brotherhood' between Turks and Kurds. The socio-economic approach, on the other hand, draws attention to improving the socio-economic status of the Kurds. By using World Values Survey data, this study tests these two distinct approaches. Logit estimates provide strong support for the socio-economic approach. Individuals with a better socio-economic status (i.e. higher level of education and income) are less likely to support Kurdish ethno-nationalist formations while religion-related factors do not have a significant impact. Some theoretical and policy implications are also provided. © 2010 Taylor & Francis.
Open Access
Does foreign direct investment promote growth? Exploring the role of financial markets on linkages
(Elsevier BV, 2010) Alfaro, L.; Chanda, A.; Ozcan, S. K.; Sayek, S.
Do multinational companies generate positive externalities for the host country? The evidence so far is mixed varying from beneficial to detrimental effects of foreign direct investment (FDI) on growth, with many studies that find no effect. In order to provide an explanation for this empirical ambiguity, we formalize a mechanism that emphasizes the role of local financial markets in enabling FDI to promote growth through backward linkages. Using realistic parameter values, we quantify the response of growth to FDI and show that an increase in the share of FDI leads to higher additional growth in financially developed economies relative to financially under-developed ones. © 2009 Elsevier B.V. All rights reserved.
Open Access
The effects of Japanese economic performance on Indonesia
(Routledge, 2006) Berument, Hakan; Ceylan, N. B.; Vural, B.
This paper assesses how Japanese economic performance affects the Indonesian economy for the 1988 to 2004 period. The empirical evidence provided here suggests that Japanese growth appreciates the local currency in real terms, decreases the inflation and increases growth. As a side issue, we also documented that real exchange rate depreciation accelerates inflation and decreases growth in Indonesia. © 2006 Taylor & Francis.
Open Access
Emergent local initiative and the city: the case of neighbourhood associations of the better-off classes in post-1990 urban Turkey
(Sage Publications Ltd., 2007) Erman, T.; Yıldar, M. C.
This article investigates the voluntary local organisations of the better-off classes in the Turkish urban context. Based on empirical research conducted with four neighbourhood associations (NAs), information is provided regarding their process of establishment, leadership, autonomy, goals and projects, resources and obstacles, which points to the significance of context. The research demonstrates that Turkish NAs differ from those in the West in terms of their commitment to ideological as much as pragmatic issues. In their response to the 'Islamist' versus 'secularist' polarisation in society, they seek to create their own localities as the places of secular and cosmopolitan people; and in their response to the increasingly unregulated and poorly serviced city, they struggle to create orderly localities protected from unlawful rent-seeking practices and equipped with adequate amenities. The NAs may be regarded as civic initiatives that empower the locality. Yet, by doing so, they may cause uneven development in urban space.
Open Access
An empirical analysis of issue templates on GitHub
(2023-01) Sülün, Emre
Many open-source software projects use GitHub Issues for issue tracking. Unlike other issue trackers, the initial versions of GitHub Issues were highly flexible and had no standard way of using it. Its unstructured nature may have made it prone to incomplete issue reports that may negatively affect software development and maintenance productivity. To potentially address these problems, GitHub introduced issue templates in 2016. This thesis aims to reflect the current status of issue template usage by mining open-source projects. Also, we analyze how the templates have evolved since their introduction in 2016 and further investigate the impact of issue templates on several issue tracking metrics, such as time to resolution, the number of reopens, and the number of comments. We evaluated 350 templates and their previous versions from 100 large-scale and popular open-source projects. We also analyzed 1,916,057 issues to understand their conformance to templates and the impact of issue templates. Lastly, we conducted a survey with open-source software maintainers to understand their opinions about issue templates. We found that issue templates are almost always used (99 out of 100 projects). The historical analysis suggests that issue forms, which are more structured issue templates, started to gain popularity over vanilla issue templates. We also observed that issues created when the project has an issue template are statistically resolved faster (p-value 0.00, effect size 0.59) and have less number of comments. Similarly, when issue forms are used, time to resolution, the number of reopenings and the length of discussion significantly decrease. According to the survey, 85% of project maintainers agree with the benefits and they believe issue templates construct a balanced midpoint between the flexibility of vanilla issues and the strictness of other issue tracking systems such as Jira.
Open Access
Environment Kuznets curve for CO2 emissions: a cointegration analysis for China
(Elsevier Ltd, 2009) Jalil, A.; Mahmud, S. F.
This study examines the long-run relationship between carbon emissions and energy consumption, income and foreign trade in the case of China by employing time series data of 1975-2005. In particular the study aims at testing whether environmental Kuznets curve (EKC) relationship between CO2 emissions and per capita real GDP holds in the long run or not. Auto regressive distributed lag (ARDL) methodology is employed for empirical analysis. A quadratic relationship between income and CO2 emission has been found for the sample period, supporting EKC relationship. The results of Granger causality tests indicate one way causality runs through economic growth to CO2 emissions. The results of this study also indicate that the carbon emissions are mainly determined by income and energy consumption in the long run. Trade has a positive but statistically insignificant impact on CO2 emissions. © 2009 Elsevier Ltd. All rights reserved.
Open Access
Globalisation and/or Europeanisation? the case of flexicurity
(Routledge, 2013) Tsarouhas, D.; Ladi, S.
The relationship between globalisation and Europeanisation is conventionally studied by focusing on the domestic level. In this article we explore this relationship at the international level instead. We examine the way in which the two phenomena in the form of the ILO and the EU relate to one another. Adopting a discursive institutionalist approach and focusing on flexicurity, we investigate whether, how and under what conditions the discourse on flexicurity provides a point of convergence or divergence between globalisation and Europeanisation. Our empirical data reveals attempts by the European Commission to use globalisation as a legitimating device for a market-accommodating programme for labour market reform. The ILO remains more sceptical, both about the overall effects of globalisation and the more concrete uses of flexicurity. Meanwhile, the concept of flexicurity is subject to change and rearticulation in line with the evolving policy agenda endorsed by the Commission and/or the member states. The relationship between Europe and globalisation is thus far from neutral. 'Europe' is active in shaping globalisation; translated into the work undertaken here, Europeanisation could be conceived as a facet of globalisation rather than as a bulwark to it, or merely as a process running parallel to it.
Open Access
Has European customs union agreement really affected Turkey's trade?
(Routledge, 2007) Neyaptı, B.; Taşkın, F.; Üngör, M.
The numerous discussions regarding the advantages and disadvantages of Turkey's becoming a member of the Customs Union has been inconclusive. The empirical analysis that mostly focus on the changes in the volume of trade without much regard to the conjectural changes have also been insufficient. This study attempts to shed light on this issue in a formal analysis of Turkey's international trade by empirically accounting for the changes before and after the Customs Union Agreement (CUA). In doing so, we explicitly account for the concurrent changes in the macroeconomic environment that may have affected Turkey's trade with the rest of the world. Our empirical findings indicate that CUA has not only positively impacted on Turkey's trade, but also led to changes in the behaviour of both exports and imports with regards to their responsiveness to underlying variables.
Open Access
How angel know-how shapes ownership sharing in stage-based contracts
(Sage Publications, 2019) Erzurumlu, S. S.; Joglekar, N.; Le´vesque, M.; Tanrısever, Fehmi
We draw upon stewardship theory to formally derive bounds on the investment amount in a business prospect, and to characterize ownership sharing when investors offer two-stage financing along with know-how to increase the prospect’s valuation. In the early-development stage, we show that the direct effect of investor know-how increases the entrepreneur’s share while the indirect effect from that know-how due to its interaction with the investment size, decreases it. In the subsequent growth stage, the direct effect decreases the entrepreneur’s share while the indirect effect increases it. These tradeoffs offer theoretical and practical implications for writing investment contracts involving investor know-how.
Open Access
Income inequality and economic convergence in Turkey: a spatial effect analysis
(Sage Publications, 2009) Yildirim, J.; Öcal, N.; Özyildirim, S.
Even though the convergence of regional per capita income has been a highly debated issue internationally, empirical evidence regarding Turkey is limited as well as contradictory. This article is an attempt to investigate regional income inequality and the convergence dynamics in Turkey for the time period 1987-2001. First, the Theil coefficient of concentration index is used to analyze the dispersion aspects of the convergence process. The geographically based decomposition of inequality suggests a strong correlation between the share of interregional inequality and spatial clustering. Then, we estimate convergence dynamics employing alternative spatial econometric methods. In addition to the global models, we also estimate local models taking spatial variations into account. Empirical analysis indicates that geographically weighted regression improves model fitting with better explanatory power. There is considerable variation in speed of convergence of provinces, which cannot be captured by the traditional beta convergence analysis.
Open Access
Market reaction to risky banks: did generous deposit guarantee change it?
(Pergamon Press, 2008) Önder, Z.; Özyildirim, S.
Turkey experienced a massive banking crisis in February 2001, resulting in the loss of more than a thousand managerial jobs and the closure of 21% of all bank branches in the market. In this paper, we study the behavior of the market and the banks in Turkey before the crisis, from 1988 to 2000, which includes the period of full deposit insurance. The empirical results showed that not only depositors but also borrowers reacted negatively to risky banks and punished them even more during the period of generous government guarantee. However, in the same period, banks were found to increase their moral hazard behavior significantly. Although the International Monetary Fund and the World Bank recommend explicit deposit insurance for developing countries, the findings of this paper suggest that deposit insurance may not be an effective policy tool to improve market confidence, and it does not guarantee a stable economic environment even when the market reacts negatively to the moral hazard behavior of banks.
Open Access
The time-varying effect of inflation uncertainty on inflation for Turkey
(Routledge, 2017) Varlik, S.; Ulke, V.; Berument, Hakan
We investigate the effect of inflation uncertainty on inflation from January 1982 through March 2016 for Turkey by using the Stochastic Volatility in Mean model with time-varying parameters. Our empirical evidence from consumer price index (CPI) inflation suggests that the observed positive relationship between inflation and inflation uncertainty is not robust. This positive relationship diminishes after 2002. This finding is valid for all five subcomponents of CPI inflation; however, for Health Services, Transportation Services, and Recreational and Cultural Services, an inflation-positive association is reported after 2010. © 2016 Informa UK Limited, trading as Taylor & Francis Group.