Damage to aircraft composite structures caused by directed energy system: A literature review

This paper presents a comprehensive review of the research studies on direct energy system effect on aircraft composite structures to develop a good understanding of state-of-the-art research and devel-opment in this area. The review begins with the application of composite materials in the aircraft structures and highlights their particular areas of application and limitations. An overview of directed energy system is given. Some of the commonly used systems in this category are discussed and the working principles of laser energy systems are described. The experimental and numerical studies re-ported regarding the aircraft composite structures subject to the effect of directed energy systems, especially the laser systems are reviewed in detail. In particularly, the general effects of laser systems and the relevant damage mechanisms against the composite structures are reported. The review draws attention to the recent research and findings in this field and is expected to guide engineers/researchers in future theoretical, numerical, and experimental studies.     

The dynamic and stochastic knapsack Problem with homogeneous‐sized items and postponement options

This article generalizes the dynamic and stochastic knapsack problem by allowing the decision‐maker to postpone the accept/reject decision for an item and maintain a queue of waiting items to be considered later. Postponed decisions are penalized with delay costs, while idle capacity incurs a holding cost. This generalization addresses applications where requests of scarce resources can be delayed, for example, dispatching in logistics and allocation of funding to investments. We model the problem as a Markov decision process and analyze it through dynamic programming. We show that the optimal policy with homogeneous‐sized items possesses a bithreshold structure, despite the high dimensionality of the decision space. Finally, the value (or price) of postponement is illustrated through numerical examples. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 267–292, 2015     

Linking a throughput simulation to a systems dynamics simulation to assess the utility of a US Navy foreign humanitarian aid mission

The success of any humanitarian aid mission is generally measured by the timeliness of critical supplies that are delivered to the affected area. However, a more interesting analysis may be to determine the effect of the aid on the overall satisfaction of the local population. The authors' research focused on the delivery of humanitarian aid to a notional region that was decimated by flooding with ships, landing craft and security personnel provided by the US Navy and Marines. While the research effort addressed naval force structure, the focus of the research was: (1) to assess different delivery methods for the aid; and (2) to determine how the aid delivery impacted the overall satisfaction of the local population. To examine both concerns, two simulation models were developed, with one examining the throughput of aid delivered during the operation, and the other the satisfaction of the population based on the humanitarian aid effort.     

Exact algorithms for integrated facility location and production planning problems

We consider a class of facility location problems with a time dimension, which requires assigning every customer to a supply facility in each of a finite number of periods. Each facility must meet all assigned customer demand in every period at a minimum cost via its production and inventory decisions. We provide exact branch‐and‐price algorithms for this class of problems and several important variants. The corresponding pricing problem takes the form of an interesting class of production planning and order selection problems. This problem class requires selecting a set of orders that maximizes profit, defined as the revenue from selected orders minus production‐planning‐related costs incurred in fulfilling the selected orders. We provide polynomial‐time dynamic programming algorithms for this class of pricing problems, as well as for generalizations thereof. Computational testing indicates the advantage of our branch‐and‐price algorithm over various approaches that use commercial software packages. These tests also highlight the significant cost savings possible from integrating location with production and inventory decisions and demonstrate that the problem is rather insensitive to forecast errors associated with the demand streams. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

Information sharing in multinational security and military operations. Why and why not? With whom and with whom not?

Military operations increasingly require cooperation between agencies within the same nation, but also collaboration with security and military organizations internationally. Throughout history multinational military cooperation has often been an appropriate way to conduct major operations; national manpower and material resources are generally insufficient to address the demands of missions worldwide. The desire to optimize the use of scarce research and development and investment capabilities, the need for international legitimacy and political support, and the fact that today’s risks transcend national borders, have rendered multinational cooperation in the security domain unavoidable. With joint operations comes the requirement for multi-partner- and multinational information sharing. However, information sharing has both advantages and costs, and is subject to both enabling factors as well as barriers. This paper reflects on theories, both classical and current, as well as empirical case studies, to examine the pros and cons of multinational information sharing, and the factors that conduce or interfere with the transmission and the receipt of intelligence. The importance of a holistic approach and of learning lessons learned are two key lessons gleaned from the analysis, along with an emphasis on developing both the organizational and the interpersonal enablers of information sharing.     

Validation of a strategy for harbor defense based on the use of a min‐max algorithm receding horizon control law

We present a validation of a centralized feedback control law for robotic or partially robotic water craft whose task is to defend a harbor from an intruding fleet of water craft. Our work was motivated by the need to provide harbor defenses against hostile, possibly suicidal intruders, preferably using unmanned craft to limit potential casualties. Our feedback control law is a sample‐data receding horizon control law, which requires the solution of a complex max‐min problem at the start of each sample time. In developing this control law, we had to deal with three challenges. The first was to develop a max‐min problem that captures realistically the nature of the defense‐intrusion game. The second was to ensure the solution of this max‐min problem can be accomplished in a small fraction of the sample time that would be needed to control a possibly fast moving craft. The third, to which this article is dedicated, was to validate the effectiveness of our control law first through computer simulations pitting a computer against a computer or a computer against a human, then through the use of model hovercraft in a laboratory, and finally on the Chesapeake Bay, using Yard Patrol boats. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 247–259, 2016