本研究探討等效平行機台(Identical Parallel Machine)之排程問題,考慮n個工件在m台等效平行機台上加工,工件具整備時間。工件可切割至其他機台同時進行加工,但只要工件切割,則必須加上整備時間。本研究以總完工時間最小化為目標,數學表示式為 。 首先,將所有工件之整備及作業時間相加後,以SPT法排序,再依序排入可最早開始進行加工之機台,此方法可得到 問題之最佳解。在本研究中提出五個Lemmas以證明只需切割每機台上最後一個工件可以得到最佳解。本研究提出以數學規劃模式為基礎之反覆演算法,實驗證明此方法是有效率的。本研究在n=1025, m=50,當工件之處理時間為 時,平均求解時間為1.568秒,當工件之處理時間為 時,平均求解時間為1.578秒。
We consider the problem of scheduling n jobs on m identical parallel machines with job setup time. Job can split arbitrarily to any machine with setup time incurred. Our objective is to minimize total completion and the problem is denoted as . We first sequence the job with the smallest sum of setup time and processing time to the earliest available machine. This rule gives the optimal solution to the problem. Five lemmas are proposed to prove that the optimal solution can be obtained by splitting only the last positional job on each machine. A Linear Programming model is developed to formulate this scheduling problem into an iterative procedure. Computational results indicate that our iterative algorithm is effective. The average execution time of the problem with n = 1025 combined with m = 50 and processing time and can be solved in 1.568 seconds and 1.578 seconds on average,respectively.