Fire truck relocation during major incidents

The effectiveness of a fire department is largely determined by its ability to respond to incidents in a timely manner. To do so, fire departments typically have fire stations spread evenly across the region, and dispatch the closest truck(s) whenever a new incident occurs. However, large gaps in coverage may arise in the case of a major incident that requires many nearby fire trucks over a long period of time, substantially increasing response times for emergencies that occur subsequently. We propose a heuristic for relocating idle trucks during a major incident in order to retain good coverage. This is done by solving a mathematical program that takes into account the location of the available fire trucks and the historic spatial distribution of incidents. This heuristic allows the user to balance the coverage and the number of truck movements. Using extensive simulation experiments we test the heuristic for the operations of the Fire Department of Amsterdam‐Amstelland, and compare it against three other benchmark strategies in a simulation fitted using 10 years of historical data. We demonstrate substantial improvement over the current relocation policy, and show that not relocating during major incidents may lead to a significant decrease in performance.     

The Somali National Army: an assessment

To engage properly with the Somali National Army, to understand it in the hope of improving stability and the lives of over 12 million Somalis, good basic information on its composition and characteristics is necessary. Authoritative accounts on the subject have been scarce for over 25 years. This account seeks to detail the army’s dispositions across southern Somalia, and, more importantly, the brigades’ clan compositions and linkages. Clan ties supersede loyalties to the central government. The army as it stands is a collection of former militias which suffer from ill-discipline and commit crime along with greater atrocities. Estimates of numbers are unreliable, but there might be 13,000 or more fighters in six brigades in the Mogadishu area and five beyond.     

An assumption-free convergence analysis for a perturbation of the scaling algorithm for linear programs,with application to the L1 estimation problem

This article is concerned with the scaling variant of Karmarkar's algorithm for linear programming problems. Several researchers have presented convergence analyses for this algorithm under various nondegeneracy types of assumptions, or under assumptions regarding the nature of the sequence of iterates generated by the algorithm. By employing a slight perturbation of the algorithm, which is computationally imperceptible, we are able to prove without using any special assumptions that the algorithm converges finitely to an ε-optimal solution for any chosen ε > 0, from which it can be (polynomically) rounded to an optimum, for ε > 0 small enough. The logarithmic barrier function is used as a construct for this analysis. A rounding scheme which produces an optimal extreme point solution is also suggested. Besides the non-negatively constrained case, we also present a convergence analysis for the case of bounded variables. An application in statistics to the L₁ estimation problem and related computational results are presented.     

A flow-shop problem with sequence-dependent additive setup times

The flow-shop scheduling problem with sequence-dependent additive setup times is considered as a special case of the general problem, and a polynomially bounded approximate method is developed to find a minimum makespan permutation schedule. The approximate algorithm is shown to yield optimal results for the two-machine case. A version of Sule's model is defined that produces the first approximation of the optimal solution for this problem. Computational experience along with numerical examples are provided to test the effectiveness of the method.     

Extension of Bolzano search to rectangles which preserves rectangles as iterates

Multivariable elimination algorithms, which may be regarded as generalizations of various one-dimensional search procedures, have not found wide application. A probable reason may be the generally very irregularly shaped regions of uncertainty that evolve iteratively in the procedures. Hence hope for practical salvage of this class of algorithms seems to lie in controlling the shape of the successively smaller regions of uncertainty. In this article an extension of Bolzano search to rectangles which preserves rectangular iterates is given. Since the result is essentially geometrical in nature, a geometric proof of this procedure is given. Hopefully the proof procedure will be of independent interest. A numerical illustration of the procedure is given for a game problem, such problems lending themselves to this method.     

On labeling the vertices of products of complete graphs with distance constraints

Variations of Hale's channel assignment problem, the L(j, k)‐labeling problem and the radio labeling problem require the assignment of integers to the vertices of a graph G subject to various distance constraints. The λ_j,k‐number of G and the radio number of G are respectively the minimum span among all L(j, k)‐labelings, and the minimum span plus 1 of all radio labelings of G (defined in the Introduction). In this paper, we establish the λ_j,k‐number of ∏ K for pairwise relatively prime integers t₁ < t₂ < … < t_q, t₁ ≥ 2. We also show the existence of an infinite class of graphs G with radio number |V(G)| for any diameter d(G). © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2005     

Advancing “Defence-in-depth”: intelligence and systems dynamics

This article aims to encourage the fostering of more systems thinking, and its greater exploitation, within the domain of contemporary intelligence. With particular focus on “micro systems thinking” and with reference to key intelligence processes, such as intelligence analysis, the utility of many systems dynamics within the intelligence context seeks to be further revealed. Through their greater collective harnessing, including up to “System of Systems” (“SoS”) dynamics, and promoting all that they can offer, more sophisticated overarching operational-to-strategic/policy “ends,” notably that of “defence-in-depth,” can be viably further advanced in a sustainable manner into the future. Arguably, a much-needed transformative impact on contemporary intelligence can also be increasingly realised through comprehensively engaging in and with more systems and SoS thinking. Aiding civil protection tasks, crisis management, emergency planners, and civil contingency practitioners likewise gain.     

Military Innovation and Tactical Adaptation in the Israel–Hizballah Conflict: The Institutionalization of Lesson-Learning in the IDF

This article highlights a pattern of military adaptation and tactical problem-solving utilized by the Israel Defense Forces (IDF) while engaged in protracted conflict with the Lebanese militant group Hizballah. It discusses the IDF’s recent attempts to institutionalize their historically intuitive process of ad-hoc learning by developing a formal tactical-level mechanism for ‘knowledge management’. The diffusion of this battlefield lesson-learning system that originated at lower-levels of the organization is examined, as well as its implementation and effectiveness during the 2006 Lebanon War. A nuanced analysis of IDF adaptation illustrates the dynamic interplay between both ‘top-down’ and ‘bottom-up’ processes of military innovation.