A new test for the homogeneity of inverse gaussian scale parameters based on computational approach test

In this paper, we focused on testing homogeneity of scale parameters of k Inverse Gaussian distributions (IGDs) since this distribution is one of the most common distribution for analyzing nonnegative right-skewed data. We have proposed a new test statistic based on the Computational Approach Test (CAT), which is a type of parametric bootstrap method, for testing homogeneity of scale parameters of k IGDs. Simulation results have been presented to compare the performances of the proposed method and existing methods such as the likelihood ratio test, modified likelihood ratio test and generalized likelihood ratio test in terms of type I error rate and power. The results showed that the proposed CAT is better than the others in terms of the type I error rates and powers in some cases

Dus Weıbull And Dus Inverse Weıbull Dıstrıbutıons: Parameter Estımatıon And Hypothesıs Tests

İstatistik, mühendislik, tıp, finans gibi birçok uygulamalı bilimde gerçek veri setlerinin analiz edilmesi ve modellenmesi oldukça önemlidir. Doğadaki rasgelelikten dolayı, sistemlerin bozulma davranışları doğal mekanizmalarına bağlı olarak çeşitlilik gösterebilir. Sistemlerin bahsedilen bozulma davranışları istatistiksel modeller yardımıyla açıklanabilir. Bu amaçla literatürde yaşam verilerini modellemek için önerilen birçok yaşam süresi dağılımı vardır. Bununla birlikte mevcut standart olasılık dağılımlarının kısıtlamaları veya modelleme yetersizlikleri araştırmacıları mevcut dağılımları genelleştirme ya da yeni dağılım aileleri önermeye itmiştir. Yeni dağılım aileleri üreten tekniklerden biri de DUS dönüşüm tekniğidir. Bu teknik, hesaplama ve yorumlama açısından daha kolay ve anlaşılır ayrıca yeni parametre içermeyen bir dağılım üretir. Bu çalışmada, Weibull ve inverse Weibull dağılımları temel dağılım olarak alınıp, DUS-Weibull ve DUS-inverse-Weibull dağılımları önerilmiştir. Önerilen dağılımların momentleri, basıklık ve çarpıklık katsayıları, moment çıkaran fonksiyonları ve quantil fonksiyonları gibi istatistiksel özellikleri ortaya konmuştur. Ayrıca farklı tahmin metotları için önerilen dağılımların bilinmeyen parametrelerinin tahmin edicilerinin etkinliklerini karşılaştırmak için Monte Carlo simülasyon çalışması yapılmıştır. Önerilen dağılımların lineer modellere uygulanmasını göstermek amacıyla, DW ve DIW dağılımları lineer regresyon modeline uygulanmıştır. Lineer regresyon modelinde bilinmeyen parametreleri tahmin etmek için genellikle hataların dağılımının ortalaması 0 varyansı 2 olan normal dağılıma sahip oldukları varsayılır. Ancak çoğu uygulamada genellikle hatalar normal dağılıma sahip olmazlar. Bu çalışmada, lineer regresyon modeli için, hataların dağılımı DW ve DIW olarak alınmıştır. Daha sonra, bilinmeyen regresyon parametreleri tahmin edilmiş ve bu parametrelere dayalı olarak hipotez testi için yeni test istatistikleri önerilmiştir. Önerilen regresyon tahmin edicilerinin performansları ve bunlara dayalı testler Monte Carlo simülasyon çalışması ile karşılaştırılmıştır. Çalışmanın sonunda, önerilen metedolojilerin uygulanabilirliğini göstermek için bir uygulama çalışması verilmiştir.In many applied sciences such as statistics, engineering, medicine, finance, the analysis and modeling of real data sets is very important. Due to the randomness in nature, the deterioration behavior of the systems may vary depending on their natural mechanisms. This distortion behavior of the systems can be explained with the help of statistical models. For this purpose, there are many life time distributions proposed in the literature to model life data. However, limitations or modeling insufficiencies of existing standard probability distributions have led researchers to generalize existing distributions or propose new distribution families. One of the techniques that produce new distribution families is the DUS transformation technique. This technique produces a parsimonious distribution in terms of computation and interpretation as it never contain any new parameter. In this study, Weibull and inverse Weibull distributions are taken as the basic distributions and DUSWeibull (DW) and DUS-inverse-Weibull (DIW) distributions are proposed. Moments, kurtosis and skewness coefficients, moment generating functions and quantile functions of the proposed distributions are presented. In addition, Monte Carlo simulation study is conducted to compare the efficiencies of the estimators of the unknown parameters of the proposed distributions for different estimation methods. In order to demonstrate the application of the proposed distributions to linear models, DW and DIW distributions are applied to the simple linear regression model. To estimate unknown parameters in a linear regression model, it is generally assumed that the distributions of errors have a normal distribution with mean 0 and variance 2 . In practice, however, errors do not have a normal distribution in most of the practical cases. In this study, for the linear regression model, the distribution of the errors is taken to be DW and DIW. Then, we estimate the unknown regression parameters and propose new test statistics based on them to test the hypotheses. Performances of the proposed regression estimators and the tests based on them are compared via Monte Carlo simulation study. An application is given at the end of the study to show the implementation of the proposed methodologie

Emisyon Azaltımı veya Yerel Fosil Kullanımı: İklim Değişikliği ile Mücadelede Yerel Kömür Kullanımı Anlamlı mı

Energy policy of a country today deals with provision of secure, cheap and clean energy. Among the three, secure and cheap energy has general dominance over clean energy. Countries shape their energy policies accordingly and Turkey is no different example. Strategy Plan 2015 – 2019 of Ministry of Energy and Natural Resources emphasizes exploitation of domestic coal for energy security while Turkey intends to curb her emissions by 21% until 2030. These two targets contradict in terms of climate change mitigation. Therefore, Turkey has to establish a consistent policy that secures energy but, at least, does not exacerbate greenhouse gas emissions. This study aims to seek the role of coal, wind and solar power in such an energy policy making through panel econometrics and scenario analyses. Panel data estimates reveal that coal does not contribute to global energy security. Scenario analyses show that Turkey’s use of domestic coal is vital but at the expense of climate change mitigation. On the other hand, both wind and solar contribute to country’s efforts in energy security and climate change mitigation.Günümüzde bir ülkenin enerji politikası güvenli, ucuz ve temiz enerji sağlamayı hedefler. Bu üç unsurdan, güvenli ve ucuz enerjiye, temiz enerjiye göre genellikle öncelik verilir. Ülkeler enerji politikalarını bu yönde şekillendirir ve Türkiye farklı değildir. Enerji ve Tabii Kaynaklar Bakanlığı’nın 2015 – 2019 Strateji Plan’ı enerji güvenliği açısından kömür kullanımına vurgu yapmaktadır. Bunun yanında Türkiye 2030 yılına kadar karbon emisyonlarını %21 azaltma niyetini belirtmiştir. Bu iki hedef özellikle iklim değişikliği ile mücadele açısından karşıtlık göstermektedir. Bu sebeple Türkiye enerji güvenliğini sağlarken en azından sera gazı salınımını çok fazla arttırmayacak bir enerji politikası geliştirmek zorundadır. Bu çalışma böyle bir enerji politikası yapımında kömür, rüzgar ve güneş enerjilerinin rollerini araştırmaktadır. Çalışmada panel ekonometrisi ve senaryo analizleri kullanılmıştır. Panel veri kestirimleri kömürün küresel enerji güvenliğine katkısı olmadığını ortaya koymuştur. Senaryo analizleri Türkiye için yerel kömürün kullanımının önemli olduğu göstermektedir ancak bu iklim değişikliği ile mücadele konusunu sekteye uğratmaktadır. Diğer taraftan, rüzgar ve güneş enerjileri Türkiye’nin enerji güvenliğinin sağlanması ve iklim değişikliği ile mücadele çabalarına olumlu katkı yapmaktadır.Ph.D. - Doctoral Progra

Investigation of Land Use Effects by Using a Hydrodynamic Model for Ankara Stream Watershed

Water resources, their protection and regulation are essential to meet drinking water demand and to prevent hazards, e.g. flood events. Therefore, exploring and evaluating the results of human activities with direct influence on water resources and hazardous events is of concern for researchers in the hydrology area. Especially, new developments interfering with the amount of drinking water and hazard risk are major interests as these strongly depend on the increase in population which in turn is influential for water resources. As a result of urbanization, changes in concentration time, amount of infiltrated water, and overflow rates are expected to occur. Therefore, the impact of urbanization on water resources and hazards should be investigated to avoid present and future problems such as floods, droughts, and pollution. In this study, Ankara Stream Watershed located in Ankara is selected as the study site. Ankara Stream Watershed has 7,140 km2 of drainage area and the stream length is 140 km. It flows through the residential areas and into Sakarya River. The watershed contains forest, agricultural, residential, and industrial regions. Moreover, there is a tendency of increase in the residential area due to the great potential of population growth. Ankara Stream Watershed has experienced a land use/cover change especially during the last two decades and these changes are expected to continue in the future because of population affecting land use dynamics. The aim of this study is to investigate the impact of land use change on surface runoff and flood events in Ankara Stream Watershed by employing a hydrodynamic model according to the various land use scenarios. For this purpose, first, a hydrodynamic model based on Environmental Protection Agency Storm Water Management Model (EPA SWMM) was developed for the watershed. EPA SWMM is a dynamic simulation model for the surface runoff developing on a watershed during a rainfall event and it calculates the quantity and quality of surface runoff on each subcatchment, i.e. the flow rate, depth and concentration in each conduit and junction. Next, we simulated the flow developed on the watershed under typical rainfall events with the hydrodynamic model. Finally, we selected several land use types and investigated their influence on runoff and flood occurrence by means of different scenarios, e.g. high urbanization, low forest and agricultural area, and vice versa. Thus, we observed the possible effects of human activities on surface runoff and flood risk in Ankara Stream Watershed

Evaluierung der wirtschaftsstruktur im kirschenanbau der Türkei

Acar, Musa ( Aksaray, Yazar )Cherry production has a vital role regarding income source for producers and export sources for Turkey. In Turkey, several studies have done regarding the technical practices, and most of them were not considered the economic dimension of cherry production. This research aimed to determine the production inputs, costs and profitability of cherry production. This study aims to reveal the relationship between orchard size and profitability by using general economic calculations based on Afyonkarahisar, Denizli, Isparta, İzmir, Konya and Manisa provinces, in Turkey. It is assumed that this study may be able to close the existing gap regarding other studies in the literature to a certain extent. This study support that more prominent cherry orchards had higher profits compared to smaller. The relative profit varies between 2.2 to 3.0 in the farm size groups. In this study, it was found that relative profit is the highest in the bigger-scale orchards. The most crucial problem for producers is to achieve a profitable cherry selling price. This study found the output/input ratio is high. Orchard size and production cost have a significant influence on the economic success of a cherry orchard. Production cost has a negative influence on profitability with a low cherry yield. In other words, cherry production is profitable in the research region, but some recommendations can be made within the framework of research findings to get better