Arama Sonuçları

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  • Yayın
    Identification of the material properties of microisotropic materials
    (Springer Heidelberg, 2015-07) Kiriş, Ahmet; İnan, Esin
    The vibration problem of a rectangular plate is considered in the present work. The main purpose here is to identify the upper bounds of the unknown material moduli of the microisotropic plate material. The frequency spectrum is obtained by extending Ritz Method to the present case. Three dimensional (3-D) vibration analysis is performed and some additional frequencies are observed among the classical frequencies as characterizing the microisotropic effects. These additional frequencies disappear by increasing values of microisotropic constants beyond some certain limits while the classical frequencies remain in the spectrum. The inverse problem is established for the identification of the upper bounds of the microisotropic constants as an optimization problem where an error function is minimized.
  • Yayın
    Simultaneous scheduling of football games and referees using Turkish league data
    (Blackwell Publishing Ltd, 2017-05) Atan, Sabri Tankut; Hüseyinoğlu, Olgu Pelin
    Assignment decisions of referees to football (soccer) games are highly debated in sports media. Referee assignments are typically done on a weekly basis as the league progresses. However, this practice ignores important workload constraints on referees. Moreover, referees' skill levels should also be considered in determining their assignments. In this article, we first give a mixed integer linear program formulation for the problem of simultaneously generating a game schedule and assigning main referees to games by incorporating specific rules in the Turkish league. We also approach this problem using a genetic algorithm (GA) because of the computational difficulties in solving the problem. In the GA solution pool, we suggest using templates for referee assignments that follow several referee-related workload constraints. We explain how these templates can be obtained by solving a mixed integer linear model prior to running the GA. The usage of these templates for referee assignments is conceptually similar to using a basic match schedule for game scheduling such as the one used in the Turkish Football League. We use the Turkish Football League fixtures for 2010–2013 as a case study. Experiments with the GA using real-world data show a rather modest performance in terms of computation time and objective function value. Our numerical results indicate that the problem is extremely hard to solve.