In this paper, we propose a simple and accurate method to derive the dwell time distribution of a mobile in a cell by a numerical integration approach. In practical applications, only a few traffic models have a known closed-form solution, most of the models can not be solved in closed form. Therefore a simulation or approximating method has to be used to solve the problems. To validate the accuracy of the proposed method, we apply it to a typical hard handoff traffic model with known closed-form solution and the goodness-of-fit is measured. We also apply this method to a soft handoff traffic model, which does not have a closed-form solution. Computer simulations show promising results based on the non-closed-form application.

This paper presents two man-machine reliability models. A system consists of one machine unit, one operator, and one event detecting monitor. The machine unit has three states, normal, abnormal, and failed. The event detecting monitor may fail in two ways. If a machine unit becomes abnormal, the event detecting monitor sends a signal, and the operator takes necessary actions. If the operator fails in the action in the cause of human error, the machine unit goes down. The condition of the operator is classified into two types, good and bad. The time to repair, and the human error rate both depend on the condition of the operator. The MTTF is obtained by using a Markov model and numerical computation. Furthermore, the optimal operating period which minimizes the overall cost is decided by using computer methods. Some numerical examples are shown.