Techniques for establishing ergodic and recurrence properties of continuous-valued markov chains

We present techniques for classifying Markov chains with a continuous state space as either ergodic or recurrent. These methods are analogous to those of Foster for countable space chains. The theory is presented in the first half of the paper, while the second half consists of examples illustrating these techniques. The technique for proving ergodicity involves, in practice, three steps: showing that the chain is irreducible in a suitable sense; verifying that the mean hitting times on certain (usually bounded) sets are bounded, by using a “mean drift” criterion analogous to that of Foster; and finally, checking that the chain is such that bounded mean hitting times for these sets does actually imply ergodicity. The examples comprise a number of known and new results: using our techniques we investigate random walks, queues with waiting-time-dependent service times, dams with general and random-release rules, the s-S inventory model, and feedback models.     

The Effectiveness of Coercive and Persuasive Counterinsurgency Practices since 1945

Which counterinsurgency approaches are most effective in defeating insurgencies? Counterinsurgency advocates and critics have debated the effectiveness of winning hearts and minds as well as using brute force against ordinary civilians. But little scholarship has sought to systemically compare these counterinsurgency approaches among a broad range of cases. This paper seeks to remedy this gap in the literature with an empirical analysis of 47 counterinsurgency wars from 1945–2000 to evaluate the effectiveness of coercive and persuasive approaches to counterinsurgency. To do so, I use crisp-set qualitative comparative analysis (QCA), or Boolean analysis, to identify the presence or absence of six coercive and persuasive counterinsurgency practices across all cases. This method enables me to highlight how counterinsurgency victory can be produced by combinations of practices rather than a single set of practices that might be expected to be useful across cases. The results demonstrate that many combinations of coercive, persuasive, and mixed counterinsurgency practices can lead to victory. However, more persuasive combinations of practices consistently lead to counterinsurgent victory compared to others, although limited coercion against civilians is constant in all cases of counterinsurgency. These findings cast doubt on the ability of counterinsurgents to refrain from harming civilians and suggest that victory requires a mix of both positive and negative incentives for cooperation.     

Radar pulse interleaving for multi‐target tracking

In a multifunction radar, the maximum number of targets that can be managed or tracked is an important performance measure. Interleaving algorithms developed to operate radars exploit the dead‐times between the transmitted and the received pulses to allocate new tracking tasks that might involve transmitting or receiving pulses, thus increasing the capacity of the system. The problem of interleaving N targets involves a search among N! possibilities, and suboptimal solutions are usually employed to satisfy the real‐time constraints of the radar system. In this paper, we present new tight 0–1 integer programming models for the radar pulse interleaving problem and develop effective solution methods based on Lagrangian relaxation techniques. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.