A Probabilistic Theory of the Coherence of an Information Set

Articl

The analytic torsion of the finite metric cone over a compact manifold

We give an explicit formula for the $L^2$ analytic torsion of the finite metric cone over an oriented compact connected Riemannian manifold. We provide an interpretation of the different factors appearing in this formula. We prove that the analytic torsion of the cone is the finite part of the limit obtained collapsing one of the boundaries, of the ratio of the analytic torsion of the frustum to a regularising factor. We show that the regularising factor comes from the set of the non square integrable eigenfunctions of the Laplace Beltrami operator on the cone.Comment: To appear in Journal of the Mathematical Society of Japa

Molecular Dynamics in grafted layers of poly(dimethylsiloxane) (PDMS)

Dielectric relaxation spectroscopy 10^-1 Hz to 10^6 Hz) is employed to study the molecular dynamics of poly(dimethylsiloxane) (PDMS, Mw=1.7 10^5 g/mol and Mw=9.6 10^4 g/mol as grafted films with thicknesses d below and above the radius of gyration Rg. For d smaller than Rg the molecular dynamics becomes faster by up to three orders of magnitude with respect to the bulk resulting in a pronounced decrease of the Vogel temperature T0 and hence the calorimetric glass transition temperature Tg. For d larger than Rg the molecular dynamics is comparable to that of the bulk melt. The results are interpreted in terms of a chain confinement effect and compared with the findings for low molecular eight glass forming liquids contained in nanoporous glasses and zeolites. Crystallization effects - well known for PDMS - are observed for films of thicknesses above and below Rg.Comment: 20 pages, 4 figure

Properties of GRB Host Galaxies

The transients following GRB970228 and GRB970508 showed that these (and probably all) GRBs are cosmological. However, the host galaxies expected to be associated with these and other bursts are largely absent, indicating that either bursts are further than expected or the host galaxies are underluminous. This apparent discrepancy does not invalidate the cosmological hypothesis, but instead host galaxy observations can test more sophisticated models.Comment: 5 pages, AIPPROC LaTeX, to appear in "Gamma-Ray Bursts, 4th Huntsville Symposium," eds. C. Meegan, R. Preece and T. Koshu

F-8C adaptive flight control extensions

An adaptive concept which combines gain-scheduled control laws with explicit maximum likelihood estimation (MLE) identification to provide the scheduling values is described. The MLE algorithm was improved by incorporating attitude data, estimating gust statistics for setting filter gains, and improving parameter tracking during changing flight conditions. A lateral MLE algorithm was designed to improve true air speed and angle of attack estimates during lateral maneuvers. Relationships between the pitch axis sensors inherent in the MLE design were examined and used for sensor failure detection. Design details and simulation performance are presented for each of the three areas investigated

Theoretical studies of chromospheres and winds in cool stars

Propagation of pulsational waves through the atmosphere of the M supergiant alpha Ori was explored using a time dependent hydrodynamic code. Wind properties for three FU Orionis objects were determined using radiative transfer models based on optical line profiles. The effects of varying wind temperature while keeping the velocity steady were considered. Using the premise that FU Orionis eruptions result from massive accretions from a disk into a T Tauri star explains a variety of observational peculiarities of FU Orionis objects

The effect of circumferential distortion on fan performance at two levels of blade loading

Single stage fans designed for two levels of pressure ratio or blade loading were subjected to screen-induced circumferential distortions of 90-degree extent. Both fan rotors were designed for a blade tip speed of 425 m/sec, blade solidity of 1.3 and a hub-to-tip radius ratio of 0.5. Circumferential measurements of total pressure, temperature, static pressure, and flow angle were obtained at the hub, mean and tip radii at five axial stations. Rotor loading level did not appear to have a significant influence on rotor response to distorted flow. Losses in overall pressure ratio due to distortion were most severe in the stator hub region of the more highly loaded stage. At the near stall operating condition tip and hub regions of (either) rotor demonstrated different response characteristics to the distorted flow. No effect of loading was apparent on interactions between rotor and upstream distorted flow fields

The long and winding road: Routine creation and replication in multi-site organizations

Prior research on organizational routines in the ‘capabilities’ literature has either studied how new routines are created during an exploratory process of variation and selection or how existing routines are replicated during a phase of exploitation. Few studies have analyzed the life cycle of new routine creation and replication as an integrated process. In an in-depth case study of England’s Highways Agency, this paper shows that the creation and replication of a new routine across multiple sites involves four sequential steps: envisioning, experimenting, entrenching and enacting. We contribute to the capabilities research in two ways: first, by showing how different organizational levels, capabilities and logics (cognitive and behavioural) shape the development of new routines; and second, by identifying how distinct evolutionary cycles of variation and selective retention occur during each step in the process. In contrast with prior research on replication as an exact copy of a template or existing routine, our study focuses on the replication of an entirely new routine (based on novel principles) that is adapted to fit local operational conditions during its large-scale replication across multiple sites. We draw upon insights from adjacent ‘practice research’ and suggest how capabilities and practice studies may complement each other in future research on the evolution of routines