中文摘要：

研究了具有维修速率可变化的k/n（G）表决可修系统,其中部件的工作时间和修理时间均服从负指数分布.开始时,当系统中的故障部件数小于某一阈值L时,修理工以较低的维修率修理故障的部件.如果修理工修理工作进展不顺利,故障部件数增加到阈值L时,将立即以较快的速度修理故障部件,此状态一直持续到系统中没有故障部件为止.使用马尔可夫过程理论和分析方法,得到了系统可用度、故障频度、系统首次故障前的平均时间等指标的表达式.进一步,讨论了不同条件下系统相关指标随系统参数变化的情况,并通过对特殊情形的讨论数值验证了所得结果的正确性.

英文摘要：

This paper studies an k-out-of-n：G repairable system with variable repair rates, in which the working times and repair times of components follow exponential distributions, respectively. Initially, when the number of failed components in the system is less than the threshold value L, low repair rate is provided for failed components. If the repairman＇ s work is not going well, the number of failed components increases and hits the threshold value L, the high repair rate is activated. Such high repair rate is preserved until there is no failed component in the system even if the number of failed components falls below L. Employing the Markov analysis method, we deduce the system availability, the rate of occurrence of failures of system, the mean time to failure of the system along with other system performance measures. Furthermore, we discuss the impact of various system parameters on the system reliability measures. Finally, special cases of the system is given to show the correctness of our results.