Authors:Mahmut Modanli Pages: 1 - 5 Abstract: The exact solution of third order fractional partial differential equations is obtained depending on initial-boundary value problem. The exact solutions and theorem of stability estimates is presented for this equation. Difference schemes are constructed for finite difference scheme. The stability of these difference schemes for this problem are given. Using of these methods, numerical solutions of the third order fractional partial differential equation defined by Caputo fractional derivative for fractional orders α=0.1, 0.5, 0.9 are calculated. Numerical results are compared with the exact solution and the accuracy and effectiveness of the proposed methods are investigated. PubDate: 2019-03-20 Issue No:Vol. 9, No. 3 (2019)

Authors:Hasan Huseyin Yildirim, Sakir Sakarya Pages: 6 - 14 Abstract: Energy has become one of the most important building blocks of many changes in the world, and it still maintains this quality. The demand for natural resources and energy continues to increase daily. For this reason, the supply of reliable and sustainable energy has become an important issue that concerns and occupies mankind. Of the renewable energy sources, wind energy is a clean, reliable and inexhaustible source of energy with low operating costs. Turkey is a rich nation in terms of wind energy potential. In this context, the profitability of investments made in utilising domestic and renewable energy potential is important. Investment efficiency is a very important issue before and during the investment period due to the fact that wind energy investments are high cost investments. In this study, a solution will be proposed for the replacement of inefficient wind turbines which have been installed. In the ideal solution of the issue, the remaining lifetime of the wind turbine which is to be replaced and capacity utilization at the new location of the turbine will be used as key input factors. The results showed that it was important for the relocation decision to be made early for the investment to be more profitable. In the event of delayed decisions to relocate the turbine, a high capacity factor is expected in the new location. If a high capacity factor is not achieved, the relocation of the turbine will be meaningless and losses will be incurred for the investor. Also according to the results of the analysis, in the first two years, the turbine operating at a low capacity of 19% and 17% is profitable if it works at 26% capacity until the end of its economic life when change is made in the third year. PubDate: 2019-03-19 DOI: 10.11121/ijocta.01.2019.00762 Issue No:Vol. 9, No. 3 (2019)

Authors:Sevcan Emek, Vedat Evren, Şebnem Bora Pages: 15 - 20 Abstract: This study provides a detailed explanation of a regulating mechanism of the blood glucose levels by an agent-based software engineering tool. Repast Simphony which is used in implementation of this study is an agent-based software engineering tool based on the object-oriented programming using Java language. Agent-based modeling and simulation is a computational methodology for simulating and exploring phenomena that includes a large set of active components represented by agents. The agents are main components situated in space and time of agent-based simulation environment. In this study, we present hormonal regulation of blood glucose levels by our improved agent-based control mechanism. Hormonal regulation of blood glucose levels is an important process to maintain homeostasis inside the human body. We offer a negative feedback control mechanism with agent-based modeling approach to regulate the secretion of insulin hormone which is responsible for increasing the blood glucose levels. The negative feedback control mechanism run by three main agents that interact with each other to perform their local actions in the simulation environment. The result of this study shows the local behavior of the agents in the negative feedback loop and illustrates how to balance the blood glucose levels. Finally, this study which is thought a potential implementation of agent-based modeling and simulation may contribute to the exploration of other homeostatic control systems inside the human body. PubDate: 2019-03-20 DOI: 10.11121/ijocta.01.2019.00685 Issue No:Vol. 9, No. 3 (2019)

Authors:Tuğba Akman Yıldız Pages: 21 - 30 Abstract: The aim of this paper is to investigate some optimal control strategies for a generalized tuberculosis model consisting of four compartments. We construct the model with the use of Caputo time fractional derivative. Contribution of distancing control, latent case finding control, case holding control and their combinations are discussed and the optimality system is obtained based on the Hamiltonian principle. Additionally, the non-negativity and boundedness of the solution are shown. We present some illustrative examples to determine the most effective strategy to minimize the number of infected people and maximize the number of susceptible individuals. Moreover, we discuss the contribution of the Caputo derivative and the order of the fractional derivative to efficiency of the control strategies. PubDate: 2019-04-15 DOI: 10.11121/ijocta.01.2019.00657 Issue No:Vol. 9, No. 3 (2019)

Authors:Nurullah Yilmaz, Ahmet Sahiner Pages: 31 - 38 Abstract: In this study, we deal with the nonlinear constrained global optimization problems. First, we introduce a new smooth exact penalty function for constrained optimization problems. We combine the exact penalty function with the auxiliary function in regard to constrained global optimization. We present a new auxiliary function approach and the adapted algorithm for solving non-linear inequality constrained global optimization problems. Finally, we illustrate the efficiency of the algorithm on some numerical examples. PubDate: 2019-04-15 DOI: 10.11121/ijocta.01.2019.00671 Issue No:Vol. 9, No. 3 (2019)

Authors:Turker Turkoglu, Irfan Ay Pages: 39 - 44 Abstract: The boriding process is a thermochemical surface treatment which can be applied to many iron and non-ferrous materials and improves the properties of the material such as hardness, wear resistance. In the present study, the layer thickness values of the boronized AISI 430 material were optimized using the Response Surface Methodology. Mathematical model was constructed using parameters such as temperature and time and the results were analyzed comparatively. As a result of the analysis, the optimum layer thickness value for AISI 430 material was obtained as 39.0183 µm for 1000 ºC and 5.9h and it was determined that the boriding temperature and time are effective on the boride layer formation process of AISI 430 material. Finally, the Response Surface Methodology and Face Centered Central Composite Design have been effectively applied to the boriding process. PubDate: 2019-04-23 DOI: 10.11121/ijocta.01.2019.00660 Issue No:Vol. 9, No. 3 (2019)

Authors:Özlem Türkşen, Suna Ertunç Pages: 45 - 51 Abstract: Beta-glucan (BG) has positive health effects for the mamalians. However, the BG sources have limited content of it. Besides, the production of the BG has stringent procedures with low productivity. Economical production of the BG needs the improvement of the BG production steps. In this study, it is aimed to improve the BG content during the first step of the BG production, microorganism growth step, by obtaining the optimal values of additive materials (EDTA, CaCl2 and Sorbitol). For this purpose, the experimental data sets with replicated response measures (RRM) are obtained at spesific levels of EDTA, CaCl2 and Sorbitol. Fuzzy modeling, a flexible modeling approach, is applied on the experimental data set because of the small sized data set and diffulty of satisfying probabilistic modeling assumptions. The predicted fuzzy function is obtained according to the fuzzy least squares approach. In order to get the optimal values of EDTA, CaCl2 and Sorbitol, the predicted fuzzy function is maximized based on multi-objective optimization (MOO) approach. By using the optimal values of EDTA, CaCl2 and Sorbitol, the uncertainty for predicted BG content is evaluated from the economic perspective. PubDate: 2019-05-02 DOI: 10.11121/ijocta.01.2019.00664 Issue No:Vol. 9, No. 3 (2019)

Authors:Zehra Pinar Pages: 52 - 58 Abstract: In this work, Bagley-Torvik equation is considered with conformable derivatives. The analytical solutions will be obtained via Sine-Gordon expansion method and Bernouli equation method for the two cases of Bagley-Torvik equation. We will illustrate and discuss about the methodology and solutions therefore the proposed equation has meaning in different areas of science and engineering. PubDate: 2019-05-02 DOI: 10.11121/ijocta.01.2019.00638 Issue No:Vol. 9, No. 3 (2019)