Visual Interactive Modelling in Operational Research: Successes and Opportunities

The visual interactive model is now a part of the toolbag of the operational research professional, and new applications are being reported regularly. This paper reviews the state of the practice of visual interactive modelling and attempts to identify successful application areas and opportunities for future developments.     

Transverse momentum distributions of hadrons produced in αα and αp collisions at the CERN intersecting storage rings

The inclusive production of charged hadrons has been measured in αα and αp collisions at nucleon-nucleon c.m. energies (√s_nn)of 31 and 44 GeV, respectively, for transverse momenta p_T up to 5 GeV/c in the central rapidity (y) region. at high p_T the yields are consistent with being 4 times and 16 times highere than the ones in pp interactions at y=0, for αp and αα interactions, respectively. However, an enhancement over these factors, as expected from an earlier FNAL experiment, cannot be ruled out.     

The vibration of rings of unsymmetrical cross-section

The vibration of complete uniform rings of unsymmetrical solid section is studied experimentally and numerically. Models for thick and thin rings are described and assessed with respect to accuracy. It is shown that a ring model having six degrees of freedom can predict frequencies accurately for modes of up to six nodal diameters of thick rings of arbitrary unsymmetrical cross-section.     

Spin-rotation measurements in π−p → K0Λ

The first measurements of spin-rotation in meson-baryon scattering in the resonance region are presented. These measurements, for the reaction π^?p → K⁰Λ, confirm the main predictions of a previous partial-wave analysis. Comments are made on resonant couplings in the reaction π^?p → K⁰Λ.     

Improved integer programming bounds using intersections of corner polyhedra

Consider the relaxation of an integer programming (IP) problem in which the feasible region is replaced by the intersection of the linear programming (LP) feasible region and the corner polyhedron for a particular LP basis. Recently a primal-dual ascent algorithm has been given for solving this relaxation. Given an optimal solution of this relaxation, we state criteria for selecting a new LP basis for which the associated relaxation is stronger. These criteria may be successively applied to obtain either an optimal IP solution or a lower bound on the cost of such a solution. Conditions are given for equality of the convex hull of feasible IP solutions and the intersection of all corner polyhedra.