Fixed‐interval joint‐replenishment policies for distribution systems with multiple retailers and stochastic demand

We consider a distribution system consisting of a central warehouse and a group of retailers facing independent stochastic demand. The retailers replenish from the warehouse, and the warehouse from an outside supplier with ample supply. Time is continuous. Most previous studies on inventory control policies for this system have considered stock‐based batch‐ordering policies. We develop a time‐based joint‐replenishment policy in this study. Let the warehouse set up a basic replenishment interval. The retailers are replenished through the warehouse in intervals that are integer multiples of the basic replenishment interval. No inventory is carried at the warehouse. We provide an exact evaluation of the long‐term average system costs under the assumption that stock can be balanced among the retailers. The structural properties of the inventory system are characterized. We show that, although it is well known that stock‐based inventory control policies dominate time‐based inventory control policies at a single facility, this dominance does not hold for distribution systems with multiple retailers and stochastic demand. This is because the latter can provide a more efficient mechanism to streamline inventory flow and pool retailer demand, even though the former may be able to use more updated stock information to optimize system performance. The findings of the study provide insights about the key factors that drive the performance of a multiechelon inventory control system. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 60: 637–651, 2013     

INTERNATIONAL REGIME OF FRESH FUEL SUPPLY AND SPENT FUEL DISPOSAL

Recent events in Iran and elsewhere demand a reevaluation of the need for increasing nuclear fuel supplies and assuring reliable flow of fuel to nuclear power user states vis-à-vis the need for strengthened security for all countries against the use of weapons of mass destruction (WMD). The right of countries to a guaranteed supply of nuclear energy for peaceful uses must be balanced with the global community's desire to limit flows of nuclear material and sensitive nuclear facilities that could create opportunities for nuclear proliferation. This article proposes elements of an international regime of fresh fuel supply and spent fuel disposal that will guarantee fresh fuel supplies to countries honoring their obligations under the Treaty for the Non-Proliferation of Nuclear Weapons (NPT), while reducing concerns about diversion of spent fuel for weapons purposes. A specific application to countries with small pre-commercial uranium enrichment plants is also proposed.     

A 17th-century Pikeman's Armour from Antwerp

Abstract

A recent re-examination of the arms and armour collection at the British Museum has led to the identification of a 17th-century pikeman's armour clearly associated with the city of Antwerp in modern Belgium, the only example of its kind. The three pieces: a pot, breastplate and backplate, are part of a collection bequeathed to the museum by William Burges in 1881. All three pieces can be dated to circa 1635 and are stamped with the arms of Antwerp, a stylised depiction of Antwerp castle between two hands derived from the blazon of the Margrave of Antwerp. The armour is indistinguishable from contemporary Dutch production and it is unclear whether it was made in Antwerp or whether the addition of the arms simply suggests a use in the city.     

Benders decomposition with alternative multiple cuts for a multi‐product closed‐loop supply chain network design model

In this article, we consider a multi‐product closed‐loop supply chain network design problem where we locate collection centers and remanufacturing facilities while coordinating the forward and reverse flows in the network so as to minimize the processing, transportation, and fixed location costs. The problem of interest is motivated by the practice of an original equipment manufacturer in the automotive industry that provides service parts for vehicle maintenance and repair. We provide an effective problem formulation that is amenable to efficient Benders reformulation and an exact solution approach. More specifically, we develop an efficient dual solution approach to generate strong Benders cuts, and, in addition to the classical single Benders cut approach, we propose three different approaches for adding multiple Benders cuts. These cuts are obtained via dual problem disaggregation based either on the forward and reverse flows, or the products, or both. We present computational results which illustrate the superior performance of the proposed solution methodology with multiple Benders cuts in comparison to the branch‐and‐cut approach as well as the traditional Benders decomposition approach with a single cut. In particular, we observe that the use of multiple Benders cuts generates stronger lower bounds and promotes faster convergence to optimality. We also observe that if the model parameters are such that the different costs are not balanced, but, rather, are biased towards one of the major cost categories (processing, transportation or fixed location costs), the time required to obtain the optimal solution decreases considerably when using the proposed solution methodology as well as the branch‐and‐cut approach. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

Nicholas John Spykman,the Balance of Power,and International Order

Nicholas John Spykman was probably America’s finest geopolitical theorist of the twentieth century, even though he was an active participant over the course only of five years (1938–43). He is rightly viewed as a worthy intellectual successor to Sir Halford Mackinder in Britain. Spykman originated the (Eurasian) Rimland concept, which is of continuing political and strategic utility today. He was controversial and notably outspoken while his writings make it quite clear that his concern with the acquisition of power was contextualised by serious concerns for world order.     

Should firms conceal information when dealing with common suppliers?

A firm making quantity decision under uncertainty loses profit if its private information is leaked to competitors. Outsourcing increases this risk as a third party supplier may leak information for its own benefit. The firm may choose to conceal information from the competitors by entering in a confidentiality agreement with the supplier. This, however, diminishes the firm's ability to dampen competition by signaling a higher quantity commitment. We examine this trade‐off in a stylized supply chain in which two firms, endowed with private demand information, order sequentially from a common supplier, and engage in differentiated quantity competition. In our model, the supplier can set different wholesale prices for firms, and the second‐mover firm could be better informed. Contrary to what is expected, information concealment is not always beneficial to the first mover. We characterize conditions under which the first mover firm will not prefer concealing information. We show that this depends on the relative informativeness of the second mover and is moderated by competition intensity. We examine the supplier's incentive in participating in information concealment, and develop a contract that enables it for wider set of parameter values. We extend our analysis to examine firms' incentive to improve information. © 2014 Wiley Periodicals, Inc. 62:1–15, 2015     

Smart Power and Japan’s Self-Defense Forces

Abstract

From Iraq to the Gulf of Aden and the South Pacific, this paper evaluates how far theoretical ideas about smart power manifest in operational missions of the Japan Self-Defense Forces (JSDF). To function within a ‘smart’ power context, this paper suggests that JSDF operates in ‘assisting’ mode, rather than the ‘threatening’ behavior of ‘hard’ power. JSDF also deployed alongside other Japanese ‘soft’ power tools – diplomatic, cultural, developmental, and NGOs, using tailored programs for different cultural and geographical contexts. Given constitutional constraints and public sensitivity towards coercive force, JSDF missions could be integrated more into a ‘whole-of-government’ approach advancing foreign policy goals through ‘smart power’.     

The United States and Humanitarian Assistance and Disaster Relief (HADR) in East Asia: Connecting Coercive and Non-Coercive Uses of Military Power

Abstract

Humanitarian Assistance and Disaster Relief (HADR) is increasingly important for East Asian militaries, but there is little scholarship on how HADR relates to broader national strategies. This article considers US involvement in HADR in East Asia in relation to changing conceptions of national power. HADR is frequently described as use of ‘hard’ military assets to further soft power goals. Looking at recent US experiences, this article shows that HADR also serves instrumental ends linked to traditional military objectives. Rather than considering power as ‘soft’ or ‘hard’, it argues that HADR illustrates connections between non-coercive and coercive uses of military power.     

Generation and storage dispatch in electricity networks with generator disruptions

We present methods for optimizing generation and storage decisions in an electricity network with multiple unreliable generators, each colocated with one energy storage unit (e.g., battery), and multiple loads under power flow constraints. Our model chooses the amount of energy produced by each generator and the amount of energy stored in each battery in every time period in order to minimize power generation and storage costs when each generator faces stochastic Markovian supply disruptions. This problem cannot be optimized easily using stochastic programming and/or dynamic programming approaches. Therefore, in this study, we present several heuristic methods to find an approximate optimal solution for this system. Each heuristic involves decomposing the network into several single‐generator, single‐battery, multiload systems and solving them optimally using dynamic programming, then obtaining a solution for the original problem by recombining. We discuss the computational performance of the proposed heuristics as well as insights gained from the models. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 493–511, 2015