文獻上記載多種多機台失效模式，然而欠缺系統性比較，本研究根據機台間是否有共同失效及修復週期，維修員是否有假期等因素，比較三種多機台失效模式。其中機台間沒有共同失效及修復週期模式可能有所謂的機器干涉現象，我們探討維修員假期因素對於機器干涉現象的影響，並發展及延伸必要的數學模式，經由數值案例本研究比較三種假期模式量化資訊，最後我們提出在作業管理角度下此類問題的最佳化決策。

There are several multi-server failure models in the literature. However, no systematic comparisons between models are available. This research tries to compare three types of multi-server failure models by categorizing if there are common failure and repair cycles and if repairman is allowed for vacation. Machine interference problems may arise when no common failure and repair cycles are allowed. We study the aggravated effect of machine interference problems that may arise if repairman is allowed for vacation. We derive and extend necessary mathematic models for our comparative study. Through numeric studies our models provide decision makers quantitative information about the vacation effect. Finally, we state how the optimal policy may be obtained from the viewpoint of operations management.