A robust regression technique using compound estimation

Least squares fitting of regression models is a widely used technique. The presence of outliers in the data can have an adverse effect on the method of least squares, resulting in a model that does not adequately fit to the bulk of the data. For this situation, robust regression techniques have been proposed as an improvement to the method of least squares. We propose a robust regression procedure that performs well relative to the current robust methods against a variety of dataset types. Evaluations are performed using datasets without outliers (testing efficiency), with a large percentage of outliers (testing breakdown), and with high leverage outliers (testing bounded influence). The datasets are based on 2-level factorial designs that include axial points to evaluate leverage effects. A Monte Carlo simulation approach is used to evaluate the estimating capability of the proposed procedure relative to several competing methods. We also provide an application to estimating costs for government satellites. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 125–139, 1998     

A robust policy for serial agile production systems

One of the major problems in modeling production systems is how to treat the job arrival process. Restrictive assumptions such as Markovian arrivals do not represent real world systems, especially if the arrival process is generated by job departures from upstream workstations. Under these circumstances, cost‐effective policies that are robust with respect to the nature of the arrival process become of interest. In this paper, we focus on minimizing the expected total holding and setup costs in a two‐stage produce‐to‐order production system operated by a cross‐trained worker. We will show that if setup times are insignificant in comparison with processing times, then near‐optimal policies can be generated with very robust performances with respect to the arrival process. We also present conditions under which these near‐optimal policies can be obtained by using only the arrival and service rates. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

Winston Churchill and the third front 1

The premise of most Western thinking on counterinsurgency is that success depends on establishing a perception of legitimacy among local populations. The path to legitimacy is often seen as the improvement of governance in the form of effective and efficient administration of government and public services. However, good governance is not the only basis for claims to legitimacy, especially in environments where ethnic or religious identities are politically salient. Some experience in Iraq suggests that in environments where such identities are contested, claims to legitimacy may rest primarily on the identity of who governs, rather than on how whoever governs, governs. This article outlines the intellectual foundations of existing policy and doctrine on counterinsurgency, and argues that development and analysis of counterinsurgency strategy would benefit from a greater focus on the role of ethnic and religious identity in irregular warfare.