Yazar "Yilmaz, Abdullah" seçeneğine göre listele

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    The flexible skew Laplace distribution
    (Taylor & Francis Inc, 2016) Yilmaz, Abdullah
    Skew-symmetric distributions have been discussed by several research-ers. In this article we construct a skew-symmetric Laplace distribution, which is the generalization of distribution given by Ali etal. (2009) and Nekoukhou and Alamatsaz (2012). This new distribution contains more parameters, and this induces flexibility properties, such as unimodality or bimodality. We study on some properties of this distribution. In the last section we also provide an application with a real data. Concerning example has recently been discussed by Nekoukhou etal. (2013) to apply to their model. We compare the behavior of our distribution to their distribution on this example.
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    INVERSE STEREOGRAPHIC HYPERBOLIC SECANT DISTRIBUTION: A NEW SYMMETRIC CIRCULAR MODEL BY ROTATED BILINEAR TRANSFORMATIONS
    (Ankara Univ, Fac Sci, 2021) Yilmaz, Abdullah
    The inverse stereographic projection (ISP), or equivalently, bilinear transformation, is a method to produce a circular distribution based on an existing linear model. By the genesis of the ISP method, many important circular models have been provided by many researchers. In this study, we propose a new symmetric unimodal/bimodal circular distribution by the rotated ISP method considering the hyperbolic secant distribution as a baseline distribution. Rotation means that fixing the origin and rotating all other points the same amount counterclockwise. Considering the effect of rotation on the circular distribution to be obtained with the bilinear transformation, it is seen that it actually induces a location parameter in the obtained circular probability distribution. We analyze some of the stochastic properties of the proposed distribution. The methods for the parameter estimation of the new circular model and the simulation-based compare results of these estimators are extensively provided by the paper. Furthermore, we compare the fitting performance of the new model according to its well-known symmetric alternatives, such as Von-Misses, and wrapped Cauchy distributions, on a real data set. From the information obtained by the analysis on the real data, we say that the fitting performance of the new distribution is better than its alternatives according to the criteria frequently used in the literature.
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    A new wrapped exponential distribution
    (Springer Heidelberg, 2018) Yilmaz, Abdullah; Bicer, Cenker
    We introduce a new wrapped exponential distribution named transmuted wrapped exponential (TWE) distribution, for the modeling of circular datasets by using the Transmutation Rank-Map method. This method is employed for the first time for a wrapped distribution with this study. The introduced distribution is more flexible than traditional wrapped exponential distribution. The paper provides the explicit form of important distributional properties of the introduced distribution such as expectation, median, moments, characteristic function, quantile function, hazard rate function and stress-strength reliability. Renyi and Shannon entropies are also obtained. The statistical inference problem for the TWE distribution is investigated using maximum likelihood, least squares and weighted least squares and comparative numerical study results are presented. Furthermore, we present a real dataset analysis.
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    Reliability and Validity of a New Test of Agility and Skill for Female Amateur Soccer Players
    (De Gruyter Open Ltd, 2017) Kutlu, Mehmet; Yapici, Hakan; Yilmaz, Abdullah
    The aim of this study was to evaluate the Agility and Skill Test, which had been recently developed to assess agility and skill in female athletes. Following a 10 min warm-up, two trials to test the reliability and validity of the test were conducted one week apart. Measurements were collected to compare soccer players' physical performance in a 20 m sprint, a T-Drill test, the Illinois Agility Run Test, change-of-direction and acceleration, as well as agility and skill. All tests were completed following the same order. Thirty-four amateur female soccer players were recruited (age = 20.8 +/- 1.9 years; body height = 166 +/- 6.9 cm; body mass = 55.5 +/- 5.8 kg). To determine the reliability and usefulness of these tests, paired sample t-tests, intra-class correlation coefficients, typical error, coefficient of variation, and differences between the typical error and smallest worthwhile change statistics were computed. Test results showed no significant differences between the two sessions (p > 0.01). There were higher intra-class correlations between the test and retest values (r = 0.94-0.99) for all tests. Typical error values were below the smallest worthwhile change, indicating `good' usefulness for these tests. A near perfect Pearson correlation between the Agility and Skill Test (r = 0.98) was found, and there were moderate-to-large levels of correlation between the Agility and Skill Test and other measures (r = 0.37 to r = 0.56). The results of this study suggest that the Agility and Skill Test is a reliable and valid test for female soccer players and has significant value for assessing the integrative agility and skill capability of soccer players.