The inventory packing problem

We study the problem of finding the minimum number of identical storage areas required to hold n items for which demand is known and constant. The replenishments of the items within a single storage area may be time phased so as to minimize the maximum total storage capacity required at any time. This is the inventory-packing problem, which can be considered as a variant of the well-known bin-packing problem, where one constraint is nonlinear. We study the worst-case performance of six heuristics used for that earlier problem since the recognition version of the inventory-packing problem is shown to be NP complete. In addition, we describe several new heuristics developed specifically for the inventory-packing problem, and also study their worst-case performance. Any heuristic which only opens a bin when an item will not fit in any (respectively, the last) open bin needs, asymptotically, no more than 25/12 (resp., 9/4) times the optimal number of bins. Improved performance bounds are obtainable if the range from which item sizes are taken is known to be restricted. Extensive computational testing indicates that the solutions delivered by these heuristics are, for most problems, very close to optimal in value.     

A multi-item EOQ model with inventory cycle balancing

This article concerns a multi-item, infinite-horizon, lot-sizing problem, where the objective is to minimize a total cost function made up of reordering cost, holding cost, and a cost determined by peak inventory levels. By spreading inventory replenishments over the reordering cycle, the peak inventory level can be reduced. The model permits the derivation of simultaneously optimal solutions for the length of the cycle and the individual item replenishment times within the cycle. An alternative formulation, in which total storage capacity is modeled as a constraint, is also solved.     

A platform for initial testing of multiple camouflage patterns

The human visual system is still an important factor in military warfare; military personnel receive training on effective search strategies, and camouflage that can effectively conceal objects and personnel is a key component of a successful integrated survivability strategy. Previous methods of camouflage assessment have, amongst others, used psychophysics to generate distinctiveness metrics. However, the population from which the human observers are drawn is often not well defined, or necessarily appropriate. In this experiment we designed a new platform for testing multiple patterns based on a camouflaged object detection task, and investigate whether trained military observers perform better than civilians. We use a two-alternative forced choice paradigm, with participants searching images of woodland for a replica military helmet displaying Olive Green, Multi Terrain Pattern, US Marine Pattern or, as a conspicuous control, UN Peacekeeper Blue. Our data show that there is no difference in detection performance between the two observer groups but that there are clear differences in the effectiveness of the different helmet colour patterns in a temperate woodland environment. We conclude that when tasks involve very short stimulus presentation times, task-specific training has little effect on the success of target detection and thus this paradigm is particularly suitable for robust estimates of camouflage efficacy.     

Models of scientific and technological review for the Biological and Toxin Weapons Convention

ABSTRACT

Science and technology (S&T) review is key to anticipating developments in the life sciences that may benefit or run contrary to the aims of the 1972 Biological and Toxin Weapons Convention. It serves as a mechanism for both preparing against novel biological threats and identifying the best opportunities for developing and sharing the life sciences to the fullest extent. In the age of rapidly advancing biotechnology, S&T review needs to be wide ranging, involve a diverse set of inputs, and be transparent about its methods and data. This viewpoint considers four models of S&T review and their capacity to respond to the challenge of the life sciences: standing advisory boards; ad hoc working groups; peer review; and wikis. It then identifies a hybrid model that is suitably broad, diverse, and transparent.     

The Problem of Weak Nuclear States

Governments are increasingly recognizing the problem posed by internally weak nuclear-capable states. The problem, however, is under-theorized. This article brings together literature on sovereignty and international order, the nonproliferation regime, and weak states, and introduces new concepts to provide a more structured understanding of this problem. Insight comes from focusing attention on the function and governance of two nuclear estates (termed the production and operational estates), and on their resilience to decay and disorder occurring within the state and society. Drawing on empirical observation, the authors suggest a typology of weakness in nuclear states, involving state fragmentation typified by the former Soviet Union, the “hard weak state” typified by North Korea, and the internally conflicted state typified by Pakistan. Although these types give rise to distinctive difficulties, their alleviation depends heavily on the maintenance of internal authority within the state and estates, the presence or absence of cooperative relations, and the international regulatory framework's vitality.     

Does Geopolitical Risks Predict Stock Returns and Volatility of Leading Defense Companies? Evidence from a Nonparametric Approach

Abstract

We use the k-th-order nonparametric causality test at monthly frequency over the period of 1985:1 to 2016:06 to analyze whether geopolitical risks can predict movements in stock returns and volatility of 24 global defense firms. The nonparametric approach controls for the existing misspecification of a linear framework of causality, and hence, the mild evidence of causality obtained under the standard Granger tests cannot be relied upon. When we apply the nonparametric test, we find that there is no evidence of predictability of stock returns of these defense companies emanating from the geopolitical risk measure. However, the geopolitical risk index does predict realized volatility in 50% of the companies. Our results indicate that while global geopolitical events over a period of time is less likely to predict returns, such global risks are more inclined in affecting future risk profile of defense firms.     

Hard Balancing in the Age of American Unipolarity: The Russian Response to US Ballistic Missile Defense during the Bush Administration (2001–2008)

One of the central debates in contemporary international relations scholarship concerns the issue of whether balancing has occurred in response to US-based unipolarity, and if it has, how this should be characterised. Existing research has seen analysts argue that major power responses to unipolarity can be placed in one of either three categories: an absence of balancing, soft balancing, and hard balancing. This article contributes to the scholarly literature by providing a case study of hard internal Russian balancing against the US’s development and deployment of Ballistic Missile Defense (BMD) systems during the Bush Administration (2001–08). Russian hard balancing against the US has involved: (1) fielding new strategic nuclear and conventional weapons equipped with BMD countermeasures, and, relatedly, (2) making changes in military doctrine. As a result, security dilemma dynamics are increasingly in evidence in US relations with Russia.     

The sources of the Australian tradition in irregular warfare, 1942–1974

This article had its genesis in a background study for the development of a new Australian Army counter-insurgency doctrine. Archival research showed that the Australian counter-insurgency doctrine employed in such post-1945 conflicts as Burma, Malaya, Borneo and Vietnam originated in the jungle campaigns of the South West Pacific Area during World War II. The historical record also showed that the Army's counter-insurgency doctrine, as with its World War II-jungle warfare doctrine, was a pragmatic amalgam of Australian experience and British doctrine. The article traces this process through the development of a series of doctrine manuals. It also considers the contribution of key individuals to both counter-insurgency theory and practice. This distinctively Australian approach to the development of doctrine was responsible for producing a highly successful manual, The Division in Battle: Pamphlet No. 11, Counter-Revolutionary Warfare (DIB 11), which the Army used during its involvement in Vietnam.