Michael P. Bailey

Statistical properties of out-of-frame detection schemes for digital transmission systems

The importance of the misframe times for DS1 frame synchronization has often been addressed in designing and using network elements and mediation units. By extending the work of J. H. Eu and W. W. Rollins (1991), Markov chain first passage time analysis is used to derive higher moments of the misframe times in both random and burst error environments. This methodology is of great value in evaluating frame synchronization techniques for digital transmission systems. By experimenting with several out-of-frame detection schemes and reasonable values for bit error ratio (BER), it is shown that misframe times are always approximately exponentially distributed for all schemes. >

The scientific method of choosing model fidelity

Simulation modeling currently enjoys great popularity as a tool for solving problems within Department of Defense activities. In this work we consider the process of upgrading an existing simulation model by increasing the fidelity of the model. The submodels to be upgraded and the degree to which they are upgraded should be chosen in a coherent, scientific manner. This is currently not the norm. In this work we describe a method which a simulation analyst can use to choose from a set of proposed model upgrades that accounts for both the costs of the upgrade as well as the benefits.

Simulation-based dynamic optimization: planning United States coast guard law enforcement patrols

A primary mission for the US Coast Guard (USCG) operating in coastal US waters is to interdict contraband. The USCG schedules a fleet of cutters to meet this mission and seeks a way to determine the operational efficiency of a particular schedule. This paper develops a methodology based on generating a sequence of finite-horizon dynamic programs (DPs), where each DP differs only in the way the smuggling vessels and the cutters interact. The DP takes the point of view of the smuggler who wishes to develop the smuggling strategy which maximizes some characteristic (e.g. the mean) of the profit attained. The DP explicitly accounts for a smuggler who must combine his short-run profit goals with his need to gain future information about the configuration of the cutters. We develop a Monte Carlo sampling procedure to generate estimates of the random variables used in the DP.

Solving a Class of Stochastic Minimization Problems

This work gives a methodology for analyzing a class of discrete minimization problems with random element weights. The minimum weight solution is shown to be an absorbing state in a Markov chain, while the distribution of weight of the minimum weight element is shown to be of phase type. We then present two-sided bounds for matroids with NBUE distributed weights, as well as for weights with bounded positive hazard rates. We illustrate our method using a realistic military communications problem.

Constant access systems: a general framework for greedy optimization on stochastic networks

We consider network optimization problems in which the weights of the edges are random variables. We develop conditions on the combinatorial structure of the problem which guarantee that the objective function value is a first passage time in an appropriately constructed continuous time Markov chain. The arc weights must be distributed exponentially, the method of solution of the deterministic problem must be greedy in a general sense, and the accumulation of objective function value during the greedy procedure must occur at a constant rate. We call these structures constant access systems after the third property. Examples of constant access systems include the shortest path system, the longest path system, the time until disconnection in a network of failing components, and some bottleneck optimization problems. For each system, we give the distribution of the objective function, the distribution of the solution of the problem, and the probability that a given arc is a member of the optimal solution. We...

Establishing reliability goals for naval major caliber ammunition

Abstract : In this study, we describe a decision process for establishing the threshold reliabilities for components of naval major caliber ammunition. A measure of reliability performance is described which relates directly to the weapons systems performance in a naval gunfire support environment. We use a simulation model to establish this relationship, a regression metamodel to estimate its parameters, and a simple decision process to specify component reliability thresholds which ensure that the ammunition is mission effective. We present this paper as an example of the integration of discrete event dynamic system analysis within a decision process.

Estimating service capacity using nonhomogeneous work arrivals

We explore experimental procedures for comparing the capabilities of complex discrete event service systems. Instead of measuring system capability by an analyzing or simulating the system with a constant rate of arriving work, system capability is measured as the maximum rate of work arrival for which the system has a steady state. Hence, we seek the arrival rate which causes the system to be at full capacity. This rate is arguably the best indication of the service systems capability.

Measuring Performance of Integrated Air Defense Networks Using Stochastic Networks

A model reflecting the evolution of an engagement between an integrated air defense system IADS and a penetrating strike group is presented. The engagement is modeled as an optimization problem on a network with stochastic arc lengths. We produce the distribution of our measure of effectiveness, as well as calculating the importance of each IADS agent to the performance of the overall system. We demonstrate the effectiveness of several jamming plans against the network.

Testing, evaluating, and enhancing NATO tactical communications schemes

In this paper, we describe a simulation model called TACFONE-NATO, which simulates the constitution of a multinational NATO operational force and construction of the forces tactical communications system. This communications system is designed using Standardization Agreement (STANAG) 4214, which details methods for assigning area codes and phone numbers, and constructing the routing tables used to route calls. Our sponsor needed testing and evaluation of STANAG 4214s performance, diagnosis methodology for shortcomings, enhancements to the STANAG for lateral routing and formation movement. In this paper, we describe the methods we used to test, evaluate, and enhance STANAG 4124.