Discretization of the continuous ambush game

This article further considers the two‐person continuous ambush game introduced by Ruckle. This article extends the work of Ruckle, Baston and Bostock, and Lee by considering the game for a general number of barriers. By supplanting optimal strategies from a discretized version of the game, we show that there always exists a value for the game, which, furthermore, can be found using linear programming techniques. Further to this, we show that the discrete ambush game considered by Garnaev has the same value as a continuous game, allowing many new results to be obtained in both games. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 515–529, 2003     

Optimizing fishbone aisles for dual‐command operations in a warehouse

Unit‐load warehouses store and retrieve unit‐loads, typically pallets. When storage and retrieval operations are not coordinated, travel is from a pickup and deposit (P&D) point to a pallet location and back again. In some facilities, workers interleave storage and retrieval operations to form a dual‐command cycle. Two new aisle designs proposed by Gue and Meller (“Improving the unit‐load warehouse.” In Progress in Material Handling Research: 2006. Material Handling Industry of America, Charlotte, NC, 2006) use diagonal aisles to reduce the travel distance to a single pallet location by approximately 10 and 20[percnt] for the two designs, respectively. We develop analytical expressions for travel between pallet locations for one of these—the fishbone design. We then compare fishbone warehouses that have been optimized for dual‐command to traditional warehouses that have been optimized in the same manner, and show that an optimal fishbone design reduces dual‐command travel by 10–15%. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 54: 389–403, 2009     

Optimal weapons allocation against layered defenses

We solve the problem of optimal allocation of weapons to targets in the presence of layered regional defenses. The general solution technique is an integer program transformable to a minimum-cost network flow. This model assumes the defense has perfect weapons. Results of a small sample scenario are included. Additionally, a representative attrition algorithm is described and the two models combined to form a hybrid algorithm. The hybrid algorithm allows for less-than-perfect weapons while maintaining optimality.     

Moral Aspects of “Moral Injury”: Analyzing Conceptualizations on the Role of Morality in Military Trauma

In clinical circles, the concept of “moral injury” has rapidly gained traction. Yet, from a moral philosophical point of view the concept is less clear than is suggested. That is, in current conceptualizations of moral injury, trauma’s moral dimension seems to be understood in a rather mechanistic and individualized manner. This article makes a start in developing an adequately founded conceptualization of the role of morality in deployment-related distress. It does so by reviewing and synthesizing insights from different disciplines into morality and trauma. This discussion will lead to three positions: (1) values and norms are by definition characterized by conflict, (2) moral conflict may entail important social dimensions, and (3) moral conflict may lead to altered beliefs about previously held values. These insights provide important steps in further developing conceptions of the role of morality in deployment-related suffering.     

Single-machine scheduling of stochastic jobs subject to deterioration or delay

N jobs are available for processing by a single machine. Jobs make (stochastic) progress while being processed but deteriorate while awaiting processing. The pioneering work of Browne and Yechiali, who developed scheduling policies for such models, is extended (i) to incorporate a precedence relation on the job set, delimiting the class of admissible policies, and (ii) to preemptive scheduling models. For the latter, we demonstrate that under appropriate conditions there is an optimal policy which is nonpreemptive. This is also achieved for a class of preemptive models in which processing generates delays for waiting jobs. A single class of algorithms is shown to generate optimal policies for many of the problems considered. © 1992 John Wiley & Sons, Inc.     

A generalized recursive algorithm for a class of non-stationary regeneration (scheduling) problems

Recent efforts in the field of dynamic programming have explored the feasibility of solving certain classes of integer programming problems by recursive algorithms. Special recursive algorithms have been shown to be particularly effective for problems possessing a 0–1 attribute matrix displaying the “nesting property” studied by, Ignall and Veinott in inventory theory and by Glover in network flows. This paper extends the class of problem structures that has been shown amenable to recursive exploitation by providing an efficient dynamic programming approach for a general transportation scheduling problem. In particular, we provide alternative formulations lor the scheduling problem and show how the most general of these formulations can be readily solved vis a vis recursive techniques.     

Techniques for establishing ergodic and recurrence properties of continuous-valued markov chains

We present techniques for classifying Markov chains with a continuous state space as either ergodic or recurrent. These methods are analogous to those of Foster for countable space chains. The theory is presented in the first half of the paper, while the second half consists of examples illustrating these techniques. The technique for proving ergodicity involves, in practice, three steps: showing that the chain is irreducible in a suitable sense; verifying that the mean hitting times on certain (usually bounded) sets are bounded, by using a “mean drift” criterion analogous to that of Foster; and finally, checking that the chain is such that bounded mean hitting times for these sets does actually imply ergodicity. The examples comprise a number of known and new results: using our techniques we investigate random walks, queues with waiting-time-dependent service times, dams with general and random-release rules, the s-S inventory model, and feedback models.