2,571 research outputs found
Weathering the Storm of Business Climate Rankings
This paper explores current usage of the term business climate. It discusses multiple definitions and measures of what constitutes a region's business climate. It also examines how usage of the term varies over time and geography. Finally, it addresses some issues related to business climate rankings, their role in economic development policy, and whether the multiplicity of published state rankings contribute consensus or confusion to the meaning of the term business climate.
Computing and deflating eigenvalues while solving multiple right hand side linear systems in Quantum Chromodynamics
We present a new algorithm that computes eigenvalues and eigenvectors of a
Hermitian positive definite matrix while solving a linear system of equations
with Conjugate Gradient (CG). Traditionally, all the CG iteration vectors could
be saved and recombined through the eigenvectors of the tridiagonal projection
matrix, which is equivalent theoretically to unrestarted Lanczos. Our algorithm
capitalizes on the iteration vectors produced by CG to update only a small
window of vectors that approximate the eigenvectors. While this window is
restarted in a locally optimal way, the CG algorithm for the linear system is
unaffected. Yet, in all our experiments, this small window converges to the
required eigenvectors at a rate identical to unrestarted Lanczos. After the
solution of the linear system, eigenvectors that have not accurately converged
can be improved in an incremental fashion by solving additional linear systems.
In this case, eigenvectors identified in earlier systems can be used to
deflate, and thus accelerate, the convergence of subsequent systems. We have
used this algorithm with excellent results in lattice QCD applications, where
hundreds of right hand sides may be needed. Specifically, about 70 eigenvectors
are obtained to full accuracy after solving 24 right hand sides. Deflating
these from the large number of subsequent right hand sides removes the dreaded
critical slowdown, where the conditioning of the matrix increases as the quark
mass reaches a critical value. Our experiments show almost a constant number of
iterations for our method, regardless of quark mass, and speedups of 8 over
original CG for light quark masses.Comment: 22 pages, 26 eps figure
Theorizing in information systems research: A reflexive analysis of the adaptation of theory in information systems research
In this paper we consider what it means to be an informed IS researcher by focusing attention on theory adaptation in IS research. The basic question we seek to address is: When one borrows theory from another discipline, what are the issues that one must consider? After examining the role of theory in IS research, we focus on escalation theory applied to IS projects as an example. In doing so, we seek to generate increased awareness of the issues that one might consider when adapting theories from other domains to research in our field. This increased awareness may then translate to a more informed use of theories in IS. Following a self-reflexive tale of how and why escalation theory was adopted to IS research, we offer four recommendations for theory adaptation: (1) consider the fit between selected theory and phenomenon of interest, (2) consider the theory’s historical context, (3) consider how the theory impacts the choice of research method, and (4) consider the contribution of theorizing to cumulative theory
On the properties of contact binary stars
A catalogue of light curve solutions of contact binary stars has been
compiled. It contains the results of 159 light curve solutions. Properties of
contact binary stars were studied by using the catalogue data.
As it is well known since Lucy's (1968a,b) and Mochnacki's (1981) works,
primary components transfer their own energy to the secondary star via the
common envelope around the two stars. This transfer was parameterized by a
transfer parameter (ratio of the observed and intrinsic luminosities of the
primary star). We proved that this transfer parameter is a simple function of
the mass and luminosity ratio. This newly found relation is valid for all
systems except H type systems which have a different relation.
We introduced a new type of contact binary stars: H subtype systems which
have a large mass ratio (). These systems show highly different
behaviour on the luminosity ratio - transfer parameter diagram from other
systems and according to our results the energy transfer rate is less efficient
in them than in other type of contact binary stars. We also show that different
types of contact binaries have well defined locations on the mass ratio -
luminosity ratio diagram. All contact binary systems do not follow Lucy's
relation (). No strict mass ratio - luminosity
ratio relation of contact binary stars exists.Comment: 5 pages, 4 figures, accepted for publication in A&
Site investigation for the effects of vegetation on ground stability
The procedure for geotechnical site investigation is well established but little attention is currently given to investigating the potential of vegetation to assist with ground stability. This paper describes how routine investigation procedures may be adapted to consider the effects of the vegetation. It is recommended that the major part of the vegetation investigation is carried out, at relatively low cost, during the preliminary (desk) study phase of the investigation when there is maximum flexibility to take account of findings in the proposed design and construction. The techniques available for investigation of the effects of vegetation are reviewed and references provided for further consideration. As for general geotechnical investigation work, it is important that a balance of effort is maintained in the vegetation investigation between (a) site characterisation (defining and identifying the existing and proposed vegetation to suit the site and ground conditions), (b) testing (in-situ and laboratory testing of the vegetation and root systems to provide design parameters) and (c) modelling (to analyse the vegetation effects)
Operator vision aids for space teleoperation assembly and servicing
This paper investigates concepts for visual operator aids required for effective telerobotic control. Operator visual aids, as defined here, mean any operational enhancement that improves man-machine control through the visual system. These concepts were derived as part of a study of vision issues for space teleoperation. Extensive literature on teleoperation, robotics, and human factors was surveyed to definitively specify appropriate requirements. This paper presents these visual aids in three general categories of camera/lighting functions, display enhancements, and operator cues. In the area of camera/lighting functions concepts are discussed for: (1) automatic end effector or task tracking; (2) novel camera designs; (3) computer-generated virtual camera views; (4) computer assisted camera/lighting placement; and (5) voice control. In the technology area of display aids, concepts are presented for: (1) zone displays, such as imminent collision or indexing limits; (2) predictive displays for temporal and spatial location; (3) stimulus-response reconciliation displays; (4) graphical display of depth cues such as 2-D symbolic depth, virtual views, and perspective depth; and (5) view enhancements through image processing and symbolic representations. Finally, operator visual cues (e.g., targets) that help identify size, distance, shape, orientation and location are discussed
Transformational government and assistive web base technologies
Transformational government has been on the European agenda for several years. However, progress towards realising the full potential of ICT to transform public services for older adults with age related cognitive impairments has been very limited. Highlighting such limitations this paper demonstrates how assistive web base technologies can be developed to improve the public services for older adults with age related cognitive impairments. However the paper argues that these transformations can be obstructed if there is no strong leadership and political commitment from people at many levels in public sectors and governments
Constrained simulations of the local universe: I. Mass and motion in the Local Volume
It has been recently claimed that there is no correlation between the
distribution of galaxies and their peculiar velocities within the Local Volume
(LV), namely a sphere of R=7/h Mpc around the Local Group (LG). It has been
then stated that this implies that either locally dark matter is not
distributed in the same way as luminous matter, or peculiar velocities are not
due to fluctuations in mass. To test that statement a set of constrained N-body
cosmological simulations, designed to reproduce the main observed large scale
structure, have been analyzed. The simulations were performed within the
flat-Lambda, open and flat matter only CDM cosmogonies. Two unconstrained
simulations of the flat-Lambda and open CDM models were performed for
comparison. LG-like objects have been selected so as to mimic the real LG
environment. The local gravitational field due to all halos found within each
LV is compared with the exact gravitational field induced by all matter in the
simulation. We conclude that there is no correlation between the exact and the
local gravitational field obtained by pairwise newtonian forces between halos.
Moreover, the local gravitational field is uncorrelated with the peculiar
velocities of halos. The exact gravitational field has a linear correlation
with peculiar velocities but the proportionality constant relating the velocity
with gravitational field falls below the prediction of the linear theory. Upon
considering all matter inside the LVs, the exact and local gravitational
accelerations show a much better correlation, but with a considerable scatter
independent on the cosmological models. The main conclusion is that the lack of
correlation between the local gravitation and the peculiar velocity fields
around LG-like objects is naturally expected in the CDM cosmologies.Comment: 10 pages, 19 figures. Accepted for publication in MNRA
The Kinetic Basis of Self-Organized Pattern Formation
In his seminal paper on morphogenesis (1952), Alan Turing demonstrated that
different spatio-temporal patterns can arise due to instability of the
homogeneous state in reaction-diffusion systems, but at least two species are
necessary to produce even the simplest stationary patterns. This paper is aimed
to propose a novel model of the analog (continuous state) kinetic automaton and
to show that stationary and dynamic patterns can arise in one-component
networks of kinetic automata. Possible applicability of kinetic networks to
modeling of real-world phenomena is also discussed.Comment: 8 pages, submitted to the 14th International Conference on the
Synthesis and Simulation of Living Systems (Alife 14) on 23.03.2014, accepted
09.05.201
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