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 Formulate the unrelated parallel machine scheduling problem  Consideration of availability constraint and sequencedependent setup time  Propose a tabu search algorithm to solve the formulated model.Figure A. Gantt chart for unrelated parallel machine scheduling problem Purpose:The main purpose of this study is to formulate the unrelated parallel machine scheduling problem with machine eligibility restrictions and sequence-dependent setup time and propose the efficient meta -heuristic algorithm to solve the problem. Theory and Methods:Firstly a mix-integer mathematical model has been addressed for the unrelated parallel machine scheduling problem with following assumptions; machines are unavailable at certain time intervals for maintenance activities, machines have the ability to perform just a certain series of tasks and the setup time of the machines depends on the order of the jobs. Then, due to the complexity of the addressed problem, a Tabu Search (TS) algorithm is proposed to solve large-scale problems. In order to evaluate the performance of the proposed TS algorithm, various test problems with different sizes are generated randomly. Finally, the relative percentage deviation (RPD) is used to compare the results. Results:To evaluate the efficiency of the applied TS algorithm, 60 test problems are generated randomly and classified into three categories as small, medium and large scale problems. Due to the random nature of the tabu search algorithm, each of the generated problems are solved five times and the minimum, average and maximum values of the results are reported. According to the obtained results, 14 problems out of 60 are solved in a short time with the mathematical model and the optimum solution is obtained. In all solved problems, the optimum solution is also obtained at least once with the TS algorithm. For the other 46 problems, the feasible solution obtained from the mathematical model is compared with the results of the TS algorithm. According to the comparison results, it is seen that the proposed TS algorithm achieves better results in terms of both solution time and solution quality. Conclusion:In most studies that have addressed the parallel machine scheduling problem so far, it is assumed that the machines are available during the entire planning period. Although this assumption is true in some cases, it is not true in many practical situations. Therefore, it is important to formulate the scheduling of jobs considering the machine eligibility restrictions. In this study, in addition to the identified constraints, it is aimed to minimize total tardiness and earliness to close this gap in the literature. In addition, the suggested TS algorithm for solving the problem is shown a superior performance.

ÖZET Küreselleşme ile artan rekabet ortamında mevcudiyetini devam ettirmek isteyen işletmeler mevcut kaynaklarını en etkin bir şekilde kullanarak verimliliğini artırmak zorundadır. Hem üretim hem de hizmet sektöründe müşteri talep ve çeşitliliğin artması beraberinde bazı karmaşayı getirmiştir. Bu karmaşayı engelleyebilmek için birçok yaklaşım ve yöntem geliştirilmiş olup, bunlardan en önemlisi hiç kuşkusuz yalın felsefedir. Yalın felsefeyi üretimde ilk ve en iyi uygulayan TOYOTA olup, daha sonra bu yaklaşım pek çok firma tarafından benimsenmiş ve hizmet sektöründe de kullanılmaya başlanmıştır. Özellikle de 2000'li yıllardan sonra hizmet sektöründe payı büyüyen sağlık sektöründe yalın düşünce teknikleri Lean Hospital (Yalın Hastaneler) adıyla uygulanmaya başlanmıştır. Bu çalışmada yalın düşünce sistemi, gelişimi, sağlık sektöründeki uygulamaları ve yalın düşünce uygulamaları gerçekleştirilen hastanelerde elde edilen iyileştirmeler hakkında bilgiler sunulmaktadır.

Optimization of process conditions in oriented strand board (OSB) manufacturing is a very important issue for both reducing cost and improving the quality of panels. Taguchi experimental design technique was applied to determination and optimization of the most influential controlling parameters of OSB panels such as press condition (pressure-time-temperature) and the ratio of adhesive parameters on modulus of elasticity (MOE). The value of the MOE is one of the very important mechanical properties of OSB panels. For this purpose, several experiments were conducted according to Taguchi L27 orthogonal design. The signal-to-noise (S/N) and the analysis of variance (ANOVA) were used to find the optimum levels and to indicate the impact of the controlling parameters on MOE. A verification test was also performed to prove the effectiveness of Taguchi technique. Since the predicted and the measured values were very close to each other, it was concluded that the Taguchi method was very successful in the optimization of effective parameters in OSB’s manufacturing.

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