Scheduling patients in an ambulatory surgical center

This paper presents a deterministic approach to schedule patients in an ambulatory surgical center (ASC) such that the number of postanesthesia care unit nurses at the center is minimized. We formulate the patient scheduling problem as new variants of the no‐wait, two‐stage process shop scheduling problem and present computational complexity results for the new scheduling models. Also, we develop a tabu search‐based heuristic algorithm to solve the patient scheduling problem. Our algorithm is shown to be very effective in finding near optimal schedules on a set of real data from a university hospital's ASC. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003     

Youth Between State and Rebel (Dis)Orders: Contesting Legitimacy from Below in Sub-Sahara Africa

Abstract

The Sahel has gained attention in international politics as one of the central theatres in the war on terrorism. International actors in this war seek alliances with states in the region, reinforcing the latter’s military strength and their legitimacy from outside. At the same time, increasingly-connected young populations question the legitimacy of their states, and contest that legitimacy from within and below. In the absence of states delivering any reasonable form of social contract, young people become torn between different governing orders and find themselves in a liminal space. In this article we present the cases of youth in Mali and Chad, who find themselves in a period of re-definition of their position in society and hence search for legitimate structures representation. In this search they may frame their belonging in terms of ethnicity, religion or political opposition – and increasingly also in adherence to global citizenship. New information flows and connectivity among young people in these regions, and between them and the diaspora, has given a new turn to their search for citizenship/belonging and rightful representation. However, whether their search will be successful in this geopolitical context is questionable.     

进入角约束下的载机变结构远距引导

针对一般导引律在载机远距引导中存在的问题,结合远距引导的需求,设计了远距引导的三维变结构导引律。该导引律具有较强自适应性,可以使载机以期望的进入角接近目标。仿真结果表明,载机在该导引律作用下,能以较小过载,平滑轨迹快速接近机动目标,并保证载机引导结束时占有有利的空中战术态势。     

An overview of conflict in Africa in 2014

Violent conflict escalated in Africa in 2014, with five sub-Saharan states – the Central African Republic (CAR), Nigeria, Somalia, South Sudan and Sudan – accounting for an estimated 75% of all conflict-related deaths on the continent. This paper provides an overview of the five major sub-Saharan African conflicts in 2014 and considers the underlying causes and dynamics in the Seleka/anti-Balaka conflict in the CAR, the Islamist threats of Boko Haram and al-Shabaab in Nigeria and Somalia, the civil war in South Sudan, and the long-running conflict between Sudan's government and southern and Darfuri rebels. The paper unpacks the general trends evident in these conflicts and the implications for the settlement thereof, including the targeting of civilians, ethnic and religious mobilisation and the state as epicentre of violence. The paper concludes with a brief look ahead to 2015.     

THE BRAZILIAN WAY

This article examines the positions held by Brazil under the administration of Luiz Inácio Lula da Silva (2003–present) on nuclear nonproliferation, arms control, and disarmament regimes and on contentious issues in those areas. Under Lula's government, Brazil has wanted to mediate between nuclear weapon and non-nuclear weapon states to consolidate its position as a strong negotiator and to benefit from the possible gains of this position in terms of greater participation in international institutions. It has also wanted to pressure nuclear weapon states to fulfill their disarmament obligations in order to reduce asymmetries in its relations with powerful nuclear weapon countries. At the same time, Brazil has tried to preserve its autonomy and flexibility to protect commercial secrets and preserve national security in relation to its own nuclear program.     

SDI,NATO, and the Social Composition Function

The strategic defense initiative (SDI) intends to renew the leadership of the USA on the western alliance. The initiative takes place in a period when a summation technology prevails for the aggregation of contributions of NATO allies. We investigate if SDI induces a shift in Hirshleifer’s social composition function. Panel data tests over the period 1970–1990 do not confirm any break toward a best-shot aggregator. SDI does not alter the core of deterrence. It is indeed a public good at the US level but not at the NATO level, where, it is one of the joint products of the alliance. We also investigate the lessons to be drawn for the current debates on ballistic defense.     

人车目标的自动识别

对单人、人群、机动车三类目标的特征进行了分析,找出了它们之间的不同之处,提出了对这三类目标进行分类识别的方法,并经现场检验,证明这种方法是有效的。     

Optimal FCFS allocation rules for periodic‐review assemble‐to‐order systems

In Assemble‐To‐Order (ATO) systems, situations may arise in which customer demand must be backlogged due to a shortage of some components, leaving available stock of other components unused. Such unused component stock is called remnant stock. Remnant stock is a consequence of both component ordering decisions and decisions regarding allocation of components to end‐product demand. In this article, we examine periodic‐review ATO systems under linear holding and backlogging costs with a component installation stock policy and a First‐Come‐First‐Served (FCFS) allocation policy. We show that the FCFS allocation policy decouples the problem of optimal component allocation over time into deterministic period‐by‐period optimal component allocation problems. We denote the optimal allocation of components to end‐product demand as multimatching. We solve the multi‐matching problem by an iterative algorithm. In addition, an approximation scheme for the joint replenishment and allocation optimization problem with both upper and lower bounds is proposed. Numerical experiments for base‐stock component replenishment policies show that under optimal base‐stock policies and optimal allocation, remnant stock holding costs must be taken into account. Finally, joint optimization incorporating optimal FCFS component allocation is valuable because it provides a benchmark against which heuristic methods can be compared. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 158–169, 2015     

An (s,q) inventory model with stochastic and interrelated lead times

In this article we introduce a lead time mechanism that allows simultaneous order arrivals. This mechanism ensures that orders never cross each other. For the continuous review (s, q) inventory system with constant demand, we show that the allowance of batch arrivals gives rise to a discontinuous cost function. By exploiting the special structure of this cost function, a search algorithm is derived that yields the optimal order strategy in a reasonable amount of time. The search is restricted to integer order strategies only. We also consider an approximate method of solution that is based on a related model with a continuous cost function. The results obtained by this approximation are, in general, very satisfactory. © 1995 John Wiley & Sons, Inc.     

The selection allocation problem

The Selection Allocation Problem (SAP) is a single period decision problem which involves selecting profit‐maximizing (or cost‐minimizing) activities from various distinct groups, and determining the volume of those activities. The activities in each group are selected subject to the availability of that group's resource, which is provided by either pooling or blending raw inputs from several potential sources. Imbedded in the decision process is the additional task of determining how much raw input is to be allocated to each group to form the resource for that group. Instances of this problem can be found in many different areas, such as in tool selection for flexible manufacturing systems, facility location, and funding for social services. Our goal in this paper is to identify and exploit special structures in the (SAP) and use those structures to develop an efficient solution procedure. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 707–725, 1999