Application of Calspan pitch rate control system to the Space Shuttle for approach and landing

A pitch rate control system designed for use in the shuttle during approach and landing was analyzed and compared with a revised control system developed by NASA and the existing OFT control system. The design concept control system uses filtered pitch rate feedback with proportional plus integral paths in the forward loop. Control system parameters were designed as a function of flight configuration. Analysis included time and frequency domain techniques. Results indicate that both the Calspan and NASA systems significantly improve the flying qualities of the shuttle over the OFT. Better attitude and flight path control and less time delay are the primary reasons. The Calspan system is preferred because of reduced time delay and simpler mechanization. Further testing of the improved flight control systems in an in-flight simulator is recommended

Numerical Evidence for the Observation of a Scalar Glueball

We compute from lattice QCD in the valence (quenched) approximation the partial decay widths of the lightest scalar glueball to pairs of pseudoscalar quark-antiquark states. These predictions and values obtained earlier for the scalar glueball's mass are in good agreement with the observed properties of $f_J(1710)$ and inconsistent with all other observed meson resonances.Comment: 12 pages of Latex, 3 PostsScript figures as separate uufil

International Conflict and the Individual

Also PCMA Working Paper #22.http://deepblue.lib.umich.edu/bitstream/2027.42/51189/1/422.pd

Levels of Marital Conflict Model: A Guide to Assessment and Intervention in Troubled Marriages

Also PCMA Working Paper #4.http://deepblue.lib.umich.edu/bitstream/2027.42/51106/1/338.pd

A study for active control research and validation using the Total In-Flight Simulator (TIFS) aircraft

The results of a feasibility study and preliminary design for active control research and validation using the Total In-Flight Simulator (TIFS) aircraft are documented. Active control functions which can be demonstrated on the TIFS aircraft and the cost of preparing, equipping, and operating the TIFS aircraft for active control technology development are determined. It is shown that the TIFS aircraft is as a suitable test bed for inflight research and validation of many ACT concepts

Organizing Retrieval Conferences: Action Research Process of Knowledge Development

Also PCMA Working Paper #31.http://deepblue.lib.umich.edu/bitstream/2027.42/51227/1/461.pd

Finite element analysis of wrinkling membranes

The development of a nonlinear numerical algorithm for the analysis of stresses and displacements in partly wrinkled flat membranes, and its implementation on the SAP VII finite-element code are described. A comparison of numerical results with exact solutions of two benchmark problems reveals excellent agreement, with good convergence of the required iterative procedure. An exact solution of a problem involving axisymmetric deformations of a partly wrinkled shallow curved membrane is also reported

Finite element analysis of wrinkling membranes

The finite element analysis of wrinkling membranes was investigated. The determination of stresses and deformations within large partly wrinkled membrane surfaces is a problem of significant technical interest in such areas as conceptual design and analysis of ultra lightweight spacecraft structures. A closed-form solution to an axisymmetric problem involving partial wrinkling of an inflated shallow membrane was obtained. In particular, a membrane in the shape of a sperical annulus was considered. The outer edge of the annulus was assumed to be fixed so that no displacements occur along the outer perimeter. The inner edge is assumed to be clamped to a rigid movable plug. Solutions for the complete stress, strain, and displacement fields under the assumption of inextensional material behavior are presented for the case of pure torsional loads applied to the plug, and for the case of pure axial loads applied to the plug

Complex Probabilities on R^N as Real Probabilities on C^N and an Application to Path Integrals

We establish a necessary and sufficient condition for averages over complex valued weight functions on R^N to be represented as statistical averages over real, non-negative probability weights on C^N. Using this result, we show that many path-integrals for time-ordered expectation values of bosonic degrees of freedom in real-valued time can be expressed as statistical averages over ensembles of paths with complex-valued coordinates, and then speculate on possible consequences of this result for the relation between quantum and classical mechanics.Comment: 4 pages, 0 figure

Subtle and Personal Workspace Requirements for Visual Search Tasks on Public Displays

This is the author’s version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in the Proceedings of the 2017 International Conference on Human Factors in Computing Systems on the ACM Digital Library http://dx.doi.org/10.1145/3025453.3025500We explore how users approach and define personal space on large, public displays. Our results show that users of public displays use one of two strategies for visual search tasks: minimizers create a small window and work up close to the display, and maximizers expand content to its full resolution and work at a distance. We show that these interaction styles match predicted `personal' and `subtle' interaction zones, characterize typical width and height requirements for these interactions, and show that these requirements are independent of the on-screen content's dimensions. Finally, we suggest practical guidelines for defining workspaces during personal and subtle interaction on large, public displays