Ricochet quantification using a multiple sensor approach

This study investigates the ricochet behaviour of three different small-arms projectile types using a novel ricochet measuring device.The results can be used to estimate the danger potential of ricochets on shooting ranges.A ricochet is the change of direction and velocity of a projectile after impacting an oblique surface.This impact produces strong vibrations on a rigid plate.During this impact,flexural waves travel radially outwards from the point of impact.These waves are used to determine the properties of the impactor with accelerometers situated on the target surface.With the use of two measurement plates,one can produce a ricochet and detect the velocity at the same time.Accelerometers are suitable for accurate momentum measurements of single impacts.However,depending upon strike velocity and the impact angle,a ricochet can separate in multiple fragments after being deflected.From the operational safety perspective,these fragments need to be detected,as well.The approach of a coupled sensor concept was chosen to solve this problem.Thermographic sensors were additionally used to visualise the heat which is produced after pene-trating a rubber layer pasted in front of the steel target plate.With this approach one was able to detect the position of impact.The investigations showed that the measurement system performance is better with a multiple sensor design,which includes accelerometers for the velocity,impact strength and partly the position measurement,while the thermographic sensor was used for the position measurement and partly the momentum measurement.The investigated ammunition showed plausible fragmentation behaviour,and the results can already be used to estimate the danger potential of different ammunition types.Frangible projectiles fragment to small particles already after being deflected under a small angle.However,Full Metal Jacket projectiles with or without a steel core do not fragment under angles which are less than 5°.The objective of the paper is to demonstrate the possibility of measuring the complex ricochet me-chanics of small projectiles using standard accelerometers with the adequate signal processing approach.This measuring system is supported by an off the shelf thermographic camera.     

A decomposition algorithm applied to planning the interdiction of stochastic networks

We describe the application of a decomposition based solution method to a class of network interdiction problems. The problem of maximizing the probability of sufficient disruption of the flow of information or goods in a network whose characteristics are not certain is shown to be solved effectively by applying a scenario decomposition method developed by Riis and Schultz [Comput Optim Appl 24 (2003), 267–287]. Computational results demonstrate the effectiveness of the algorithm and design decisions that result in speed improvements. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

On the asymptotic optimality of algorithms for the flow shop problem with release dates

We consider the nonpermutation flow shop problem with release dates, with the objective of minimizing the sum of the weighted completion times on the final machine. Since the problem is NP‐hard, we focus on the analysis of the performance of several approximation algorithms, all of which are related to the classical Weighted Shortest Processing Time Among Available Jobs heuristic. In particular, we perform a probabilistic analysis and prove that two online heuristics and one offline heuristic are asymptotically optimal. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

Fortifications and the European Military Balance before 1914

This article analyses the evolution of permanent fortifications in Europe between 1870 and 1914. Despite the introduction in the 1880s of high explosive shells, intensive construction continued until the eve of war. Fortifications figured prominently in armaments budgets and in offensive as well as defensive strategic planning, while their design changed radically. Nonetheless, the pattern of development worked against the Central Powers. Austria-Hungary concentrated against Italy at the expense of the Balkans and Galicia; Germany concentrated on Alsace-Lorraine, neglecting the east until 1912. Whereas France modernised its eastern fortresses, Belgium did little, enticing Germany into the envelopment strategy that would draw Britain into the First World War.     

Indian Strategic Thinking about East Asia

Since the end of the Cold War, India's strategic horizons have moved beyond its traditional preoccupations in South Asia. India is developing a strategic role in East Asia in particular. At the same time India's strategic thinking has undergone a revolution, as the country that prided itself on non-alignment has moved closer to the West. But India's culture, history and geography still fundamentally shape its worldview. In engaging with East Asia, India is guided by a mosaic of strategic objectives about extending its sphere of influence, developing a multipolar regional system and balancing against China. The interplay of these objectives will frame India's role in East Asia in coming years.     

The Freudian trap in combat motivation theory

Theories of group, and individual, motivation to fight have shown little real advancement since World War II. The lively debate between the proponents of ‘primary group’ and ideological theories has tended to preclude any other analysis. The debate has continued to generalise from the experience of the Wehrmacht and its cohesion in the face of appalling destruction. In this article I suggest that the theoretical underpinnings of the debate have revolved around one particular, and somewhat unrecognised, concept of the mind. Work on combat motivation owes a substantial debt to Freudian ideas concerning the unconscious and group psychology. Both sides of the ideology/primary group debate use Freudian ideas, often without realising it, and these concepts shape the various positions taken. Only by acknowledging and examining this underpinning can the debate move forward and produce a more general theory of combat motivation and group conflict with wider application.     

1918 Revisited1

This article re-evaluates the origins of the armistice of November 1918, drawing on German, French and British primary sources and on insights from work by political scientists on war termination. It examines why the German government decided to request a ceasefire and why the US, Britain and France decided to grant one. At first sight these decisions appear paradoxical in the light of the military-political situation at the time. In accounting for them the article stresses (on the German side) the campaigning on the Western Front over the previous months and (among Germany's opponents) the diplomatic tensions between Washington, London and Paris. Between them these considerations caused an unexpected and temporary convergence of perceived interests in favour of ending the conflict.     

Whose Hearts and Whose Minds? The Curious Case of Global Counter-Insurgency

Traditionally regarded as a secondary activity in military thinking and practice, the notion of counter-insurgency (COIN) has undergone a remarkable renaissance. This analysis traces the origins of this renaissance to two distinctive schools: a neo-classical school and a global insurgency school. The global insurgency school critiques neo-classical thought and presents itself as a more sophisticated appreciation of current security problems. An examination of the evolution of these two schools of counter-insurgency reveals how the interplay between them ultimately leaves us with a confused and contradictory understanding of the phenomenon of insurgency and the policies and strategies necessary to combat it.