12,850 research outputs found
Development of a prototype multi-processing interactive software invocation system
The Interactive Software Invocation System (NASA-ISIS) was first transported to the M68000 microcomputer, and then rewritten in the programming language Path Pascal. Path Pascal is a significantly enhanced derivative of Pascal, allowing concurrent algorithms to be expressed using the simple and elegant concept of Path Expressions. The primary results of this contract was to verify the viability of Path Pascal as a system's development language. The NASA-ISIS implementation using Path Pascal is a prototype of a large, interactive system in Path Pascal. As such, it is an excellent demonstration of the feasibility of using Path Pascal to write even more extensive systems. It is hoped that future efforts will build upon this research and, ultimately, that a full Path Pascal/ISIS Operating System (PPIOS) might be developed
Using Performance Measurement to Evaluate Strategic Human Resource Management Decisions: Kodak\u27s Experience With Profit Sharing
[Excerpt] Profit-sharing is frequently used to link employee performance and labor costs to the profitability of organizations. It represents a significant investment. Yet, \u27managers\u27 decisions regarding such human resource investments frequently do not use the same financial planning frameworks typical of other investments. This article presents a case study describing how one division at Eastman Kodak company used a strategic investment approach to plan and evaluate a profit-sharing program, and the role of performance measurement information in that approach
Natural Entropy Production in an Inflationary Model for a Polarized Vacuum
Though entropy production is forbidden in standard FRW Cosmology, Berman and
Som presented a simple inflationary model where entropy production by bulk
viscosity, during standard inflation without ad hoc pressure terms can be
accommodated with Robertson-Walker's metric, so the requirement that the early
Universe be anisotropic is not essential in order to have entropy growth during
inflationary phase, as we show. Entropy also grows due to shear viscosity, for
the anisotropic case. The intrinsically inflationary metric that we propose can
be thought of as defining a polarized vacuum, and leads directly to the desired
effects without the need of introducing extra pressure terms.Comment: 7 pages including front one. Accepted to publication, Astrophysics
and Space Science, subjected to a minor correction, already submitte
Environmental effects on silicon solar cells
Test results indicate that solder coating cells produces protective or deleterious effect, depending on the environment. Major problem for solder coated cells is in control of solder thickness and uniformity. Problem area for non-solder coated cells is not identified
Study of incomplete models of dynamic structures
Incomplete models of dynamic structure
Turbulence measurements using the laser Doppler velocimeter
The photomultiplier signal representing the axial velocity of water within a glass pipe is examined. It is shown that with proper analysis of the photomultiplier signal, the turbulent information that can be obtained in liquid flows is equivalent to recent hot film studies. In shear flows the signal from the laser Doppler velocimeter contains additional information which may be related to the average shear
Predictability and hierarchy in Drosophila behavior
Even the simplest of animals exhibit behavioral sequences with complex
temporal dynamics. Prominent amongst the proposed organizing principles for
these dynamics has been the idea of a hierarchy, wherein the movements an
animal makes can be understood as a set of nested sub-clusters. Although this
type of organization holds potential advantages in terms of motion control and
neural circuitry, measurements demonstrating this for an animal's entire
behavioral repertoire have been limited in scope and temporal complexity. Here,
we use a recently developed unsupervised technique to discover and track the
occurrence of all stereotyped behaviors performed by fruit flies moving in a
shallow arena. Calculating the optimally predictive representation of the fly's
future behaviors, we show that fly behavior exhibits multiple time scales and
is organized into a hierarchical structure that is indicative of its underlying
behavioral programs and its changing internal states
Creation of entanglement in a scalable spin quantum computer with long-range dipole-dipole interaction between qubits
Creation of entanglement is considered theoretically and numerically in an
ensemble of spin chains with dipole-dipole interaction between the spins. The
unwanted effect of the long-range dipole interaction is compensated by the
optimal choice of the parameters of radio-frequency pulses implementing the
protocol. The errors caused by (i) the influence of the environment,(ii)
non-selective excitations, (iii) influence of different spin chains on each
other, (iv) displacements of qubits from their perfect locations, and (v)
fluctuations of the external magnetic field are estimated analytically and
calculated numerically. For the perfectly entangled state the z component, M,
of the magnetization of the whole system is equal to zero. The errors lead to a
finite value of M. If the number of qubits in the system is large, M can be
detected experimentally. Using the fact that M depends differently on the
parameters of the system for each kind of error, varying these parameters would
allow one to experimentally determine the most significant source of errors and
to optimize correspondingly the quantum computer design in order to decrease
the errors and M. Using our approach one can benchmark the quantum computer,
decrease the errors, and prepare the quantum computer for implementation of
more complex quantum algorithms.Comment: 31 page
Improving the sensitivity of FM spectroscopy using nano-mechanical cantilevers
It is suggested that nano-mechanical cantilevers can be employed as high-Q
filters to circumvent laser noise limitations on the sensitivity of frequency
modulation spectroscopy. In this approach a cantilever is actuated by the
radiation pressure of the amplitude modulated light that emerges from an
absorber. Numerical estimates indicate that laser intensity noise will not
prevent a cantilever from operating in the thermal noise limit, where the high
Q's of cantilevers are most advantageous.Comment: 5 pages, 1 figur
Effect of Computer Keyboard Slope on Wrist Position and Forearm Electromyography of Typists Without Musculoskeletal Disorders
Positioning a computer keyboard with a downward slope reduces wrist extension needed to use the keyboard and has been shown to decrease pressure in the carpal tunnel. However, whether a downward slope of the keyboard reduces electromyographic (EMG) activity of the forearm muscles, in particular the wrist extensors, is not known. Subjects and Methods. Sixteen experienced typists participated in this study and typed on a conventional keyboard that was placed on slopes. Electromyographic activity of the extensor carpi ulnaris (ECU), flexor carpi ulnaris (FCU), and flexor carpi radialis (FCR) muscles was measured with surface electrodes, while the extension and ulnar deviation angles of the right and left wrists were measured with electrogoniometers. Results. Wrist extension angle decreased from approximately 12 degrees of extension while typing on a keyboard with a 7.5-degree slope to 3 degrees of flexion with the keyboard at a slope of –15 degrees. Although the differences were in the range of 1% to 3% of maximum voluntary contraction (MVC), amplitude probability distribution function (APDF) of root-mean-square EMG data points from the ECU, FCU, and FCR muscles varied across keyboard slopes. Discussion and Conclusion. Wrist extension decreased as the keyboard slope decreased. Furthermore, a slight decrease in percentage of MVC of the ECU muscle was noted as the keyboard slope decreased. Based on biomechanical modeling and published work on carpal tunnel pressure, both of these findings appear to be positive with respect to comfort and fatigue, but the exact consequences of these findings on the reduction or prevention of injuries have yet to be determined. The results may aid physical therapists and ergonomists in their evaluations of computer keyboard workstations and in making recommendations for interventions with regard to keyboard slope angle. [Simoneau GG, Marklin RW, Berman JE. Effect of computer keyboard slope on wrist position and forearm electromyography of typists without musculoskeletal disorders. Phys Ther. 2003;83:816–830.
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