I this paper we consider workforce management in repair/maintenance environments in which repairmen are cross-trained fo affend more than one fype of machine. In this confext, we sfudy the machine-repairman problem wifh heferogeneous machines buf with partially cross-trained repairmen. We introduce simple repairmanassignment rules as well as machine-priority rules thaf are effecfive in mirumizi...

This paper refers to some closed two-stage queueing systems with state-dcpendent vacation policy. By means of the markovian rcnewal process and the stochastic decomposition formulas of the quantities in equilibrium for M/Gjl vacation models, we derive both stationary distributions of the queue length and the cyclic time for the closed state-dependcnt vacation model. We try to so!\'e the problem...

In this paper, we analyze a single-server vacation queue with a general arrival process. Two policies, working vacation and vacation interruption, are connected to model some practical problems. The GI/M/1 queue with such two policies is described and by the matrix analysis method, we obtain various performance measures such as mean queue length and waiting time. Finally, using some numerical e...

In this paper, we investigate a single server batch arrival non-Markovian retrial queueing model with random break down and Bernoulli vacation. Customers arrive in batches accordingly Poisson process with arrival rate λ but are served one by one with first come first served basis. All customers demand the first essential service, whereas only some of them demand the second optional service. The...

This paper examines the operating characteristics of an M/G/1 retrial queueing system under Bernoulli vacation schedule with setup times. The server renders first phase of essential service (FPS) to all the arriving units whereas second phase of multi-optional services (SPS) to only some of them who demand for the same. The server may breakdown according to Poisson process in working state i.e....

In this paper, we model a cold standby repairable system with one repairman. Suppose that the system consists of two dissimilar components and one repairman, in which component 1 is the major working unit and component 2 is the cold stand-by unit, component 1 has priority in use and repair; then the repairman takes a single vacation. Under these assumptions , we derive a model of partial differ...

Services play a vital role in economies of nations and in world commerce. An economy cannot operate without the services provided by service firms. In its turn, a service firm cannot survive without a sound competitive strategy. Management of service systems is a continuous challenge, due to the dynamic and random nature of the service environment. The theory of waiting lines provides insight a...

The incidence of Dengue epidemiologic disease has grown in recent decades. In this paper an application of optimal control in Dengue epidemics is presented. The mathematical model includes the dynamic of Dengue mosquito, the affected persons, the people’s motivation to combat the mosquito and the inherent social cost of the disease, such as cost with ill individuals, educations and sanitary cam...

In this paper, we study an unreliable multi-product production/inventory system consisting of N production machines and an assembly machine. The final products are assembled-to-order whereas components are built at N separate production machines on a make-to-stock routine. The objective of our study is to develop an integrated optimal control policy that minimizes the total long-run average cos...