Bayesian inference for a Lanchester type combat model

We undertake inference for a stochastic form of the Lanchester combat model. In particular, given battle data, we assess the type of battle that occurred and whether or not it makes any difference to the number of casualties if an army is attacking or defending. Our approach is Bayesian and we use modern computational techniques to fit the model. We illustrate our method using data from the Ardennes campaign. We compare our results with previous analyses of these data by Bracken and Fricker. Our conclusions are somewhat different to those of Bracken. Where he suggests that a linear law is appropriate, we show that the logarithmic or linear‐logarithmic laws fit better. We note however that the basic Lanchester modeling assumptions do not hold for the Ardennes data. Using Fricker's modified data, we show that although his “super‐logarithmic” law fits best, the linear, linear‐logarithmic, and logarithmic laws cannot be ruled out. We suggest that Bayesian methods can be used to make inference for battles in progress. We point out a number of advantages: Prior information from experts or previous battles can be incorporated; predictions of future casualties are easily made; more complex models can be analysed using stochastic simulation techniques. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 541–558, 2000     

Automated air load planning

We describe the development of a heuristic algorithm for determining efficient 2-dimensional packings in cargo aircraft where cargo placement constraints are critically important in determining the feasibility of packing locations. We review the performance of a new algorithm versus some traditional ones for aircraft loading. The algorithm is also tested in a more generalized setting where there exist no additional constraints on items, to suggest applicability in other environments. The new algorithm has been used worldwide in the Automated Air Load Planning System (AALPS) for cargo aircraft loading, with much success. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 751–768, 1998     

Forecast horizons for the discounted dynamic lot-size problem allowing speculative motive

This article considers the dynamic lot-size problem under discounting, allowing speculative motive for holding inventory. A variable rolling-horizon procedure is presented, which, under certain regularity conditions, is guaranteed to generate an infinite-horizon optimal-production plan. We also discuss a fixed rolling-horizon procedure which provides a production plan that achieves an infinite-horizon cost within a user-specified tolerance ϵ of optimality. The fixed-horizon length T* needed in this procedure is given in terms of a closed-form formula that is independent of specific forecasted demands. We also present computational results for problems with a range of cost parameters and demand characteristics.     

Operating characteristics of a two-echelon inventory system for repairable and consumable items under batch ordering and shipment policy

In this article we have generalized previous models on multiechelon recoverable inventory systems to cover the cases of batch ordering and shipment policy, and when items can either be repaired or condemned. The batch ordering and shipment policy is appropriate when the setup cost for shipment and order and/or the demand rates of the items are relatively high. The operating characteristics of such a system have been studied. Specifically, the probability distribution of backorder levels at the bases are analyzed for different repair-time distributions. An approximation scheme is proposed for this distribution, and is evaluated using extensive simulation results. The results indicate that the scheme is very effective in providing near-optimal stocking levels in such a system.     

Implementing sustainable mission command in the Hellenic Army

The modern Mission Command philosophy in military operations originated with the German concept of Auftragstaktik (mission tactics). It emphasizes in general terms the exercise of disciplined initiatives by subordinates during the execution of mission-type orders in the course of military operations that are conducted within the overall intent of a commander. The present paper contains an overview of the historical evolution of the mission command concept and its application. The paper compares the mission command concept with the detailed or linear method of command. This paper focuses on the relevance of the mission command concept for the Hellenic Land Forces (HLF) in Greece. The paper provides a historical account on when and where mission command was successfully exercised by the Hellenic Armed Forces in the modern military history of Greece. The authors support the premise that the mission command concept is essential for safeguarding Greek national security in the current environment of evolving symmetric and asymmetric threats, and in meeting operational challenges in a diverse and difficult terrain. The paper examines the cultural reasons that have impeded the adoption of the mission command concept within the HLF and recommends a three-phase model for its permanent implementation.     

An analytic basis for decision support in negotiations

Mediators increase the effectiveness of negotiation processes. The art of mediation includes interpersonal skills, ability to convince, and proficiency in argumentation. The science of mediation represents an analytical approach to problem solving, a systematic analysis of the process, of players' positions, and of their goals, aspirations, and concessions. Analytical tools for mediation can be used by mediators, but these tools can also support negotiators in their analysis, verification of their positions, and choices. The knowledge of effective and safe alternatives, of sets of compromises, and the knowledge of the possible outcomes of concessions may be used to develop an effective strategy and to increase a negotiator's bargaining power. Models to analyze alternatives, to verify concessions made by the opponents, to determine effective alternatives, and to search for solutions that yield mutual gains, to aggregate opponents' proposals, to look for coalition members, and to simulate some of the actions of a mediator are discussed in the article.     

Optimal sequential replenishment of ships during combat

A carrier battle group is operating in an area where it is subject to attack by enemy aircraft. It is anticipated that air raids will occur in large waves. The uncertain time between raids is available for the replenishment of supplies. We consider the problem of how best to schedule ammunition replenishment during this period. The theory of Gittins indices provides the technical background to the development of a range of models which yield a hierarchy of index-based heuristics for replenishment. One such heuristic is assessed computationally in a more realistic scenario than is explicitly allowed for by the models.     

Minimizing flow time on a single machine with job classes and setup times

We examine the static sequencing problem of ordering the processing of jobs on a single machine so as to minimize the average weighted flow time. It is assumed that all jobs have zero ready times, and that the jobs are grouped into classes with the property that setup tasks are only required when processing switches from jobs of one class to jobs of another class. The time required for each setup task is given by the sum of a setdown time from the previous class and a setup time for the new class. We show that an algorithm presented in the literature for solving a special case of this problem gives suboptimal solutions. A number of properties of the optimal solution are derived, and their use in algorithms is evaluated. Computational results are presented for both a branch-and-bound procedure and a simpler depth-first search.     

一类二阶微分方程Poincaré分岔极限环的不存在性

讨论一类二阶微分方程x¨+εf(x,x.)x.+g(x)=0的Poincar分岔极限环的不存在性,利用一阶Mel’nikov函数直接从整体上进行分析讨论,得出了若干充分条件和判别准则。