In applications such as airport operations, militarysimulations, and medical simulations, conductingsimulations in accurate and realistic settings that are represented byreal video imaging sequences becomes essential. This paper surveys recent work that enablesvisually realistic model constructions and the simulation of syntheticobjects which are inserted in video sequences, and illustrates how synthetic objects canconduct intelligent behavior within a visual augmented reality.

We consider a G-network with Poisson flow of positive customers.Each positive customer entering the network is characterized bya set of stochastic parameters: customer route, the length of customer route,customer volume and his service length at each route stage aswell. The following node types are considered:Negative customers arriving at each node also form a Poisson flow.A negative customer entering a node with k customers in service, withprobability 1/k chooses one of served positivecustomer as a “target”. Then, if the node is of a type 0the negative customer immediately “kills” (displaces from the network)the target customer, and if the node is of types 1–3the negative customer with given probability depending on parameters of thetarget customer route kills this customer and with complementary probability hequits the network with no service.A product form for the stationary probabilities of underlyingMarkov process is obtained.

We consider a Markov decision process for an MX/M/1 queue that iscontrolled by batches of negative customers. More specifically, we deriveconditions that imply threshold-type optimal policies, under either thetotal discounted cost criterion or the average cost criterion. Theperformance analysis of the model when it operates under a giventhreshold-type policy is also studied. We prove a stability condition and acomplete stochastic comparison characterization for models operating underdifferent thresholds. Exact and asymptotic results concerning thecomputation of the stationary distribution of the model are also derived.

A single-server queueing system with a batch Markovian arrivalprocess (BMAP) and MAP-input of disasters causing all customers toleave the system instantaneously is considered. The system has twooperation modes, which depend on the current queue length. Theembedded and arbitrary time stationary queue length distributionhas been derived and the optimal control threshold strategy hasbeen determined.

In this paper we propose a family of finite approximations for the departure process of an ME/ME/1 queue indexed by a parameter k defined as the system size of the finite approximation. The approximations capture the interdeparture times from an ME/ME/1 queue exactly and preserve the lag correlations of inter-event times of the departures from an ME/ME/1 queue up to lag (k - 1).