A Kitti Kittisup creator Erke, Tapio J. Chairperson Kolkki, Raimo Examination committee Takahashi, Kenzo Examination committee Royal Thai Navy Scholarship donor text series technical report th Bangkok Asian Institute of Technology 1994 continuing eng 39 leaves Reliability in a circuit-switched telecommunication network is acknowledged as a very important quality measure. In general, it is treated separately from some other performance measures such as grade of service. This may not give a good reflection of the overall network performance. Therefore this research study employs a method of combining reliability with another quality measure to give a more realistic measure for the overall network performance. By means of developing a perturbation analysis based model, perturbation estimate or gradient of each component in the network can be calculated from each global network state in the network state space. Component with the largest gradient is identified as a critical component for reliability improvement. Finally, a comparison study between reliability improvement of a network using and without using perturbation analysis based model is also carried out. The network using perturbation analysis based model shows a superior performance in overall network performance than the network without using perturbation analysis based model. A research submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology Research Studies Project Report (M.Eng.) - Asian Institute of Technology, 1994 Telecommunication Switching systems Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B15593 http://203.159.5.9/ait-thesis/detail.php?q=B15593 121095 20260818171717.0