Covert Canucks: Intelligence Gathering and the 1924 Voyage of HMCS Thiepval in the North Pacific Ocean

In 1924, HMCS Thiepval provided logistical support to a British attempt to circumnavigate the world by air. But the ship had another secret mission. Concerned America and Japan were fortifying their north Pacific possessions in violation of the 1922 Washington Treaty, and fearing war might be inevitable, the Canadian navy sent the Thiepval to covertly spy upon American and Japanese facilities. No cheating was discovered, but in the longer run, Canadian concerns about hostilities in the north Pacific were ‘on the mark’ correct.     

Investigating the Desirability of Navy Aircraft Service Life Extension Programs

Building on prior work on optimal replacement of aging aircraft, this paper presents three methodologies to evaluate prospective aviation Service Life Extension Programs (SLEPs) and applies these methodologies to US Navy F/A-18E/F data. While considerable uncertainty remains as to the values of key parameters (e.g. the cost of F/A-18E/F SLEPs), the preponderance of the evidence available at this juncture favors undertaking SLEPs on F/A-18E/Fs rather than replacing them with new Joint Strike Fighters.     

A lagrangean relaxation algorithm for the constrained matrix problem

We present variants of a convergent Lagrangean relaxation algorithm for minimizing a strictly convex separable quadratic function over a transportation polytope. The algorithm alternately solves two “subproblems,” each of which has an objective function that is defined by using Lagrange multipliers derived from the other. Motivated by the natural separation of the subproblems into independent and very easily solved “subsubproblems,” the algorithm can be interpreted as the cyclic coordinate ascent method applied to the dual problem. We exhibit our computational results for different implementations of the algorithm applied to a set of large constrained matrix problems.