25,487 research outputs found
Design criteria for a PC-based common user interface to remote information systems
A set of design criteria are presented which will allow the implementation of an interface to multiple remote information systems on a microcomputer. The focus of the design description is on providing the user with the functionality required to retrieve, store and manipulate data residing in remote information systems through the utilization of a standardized interface system. The intent is to spare the user from learning the details of retrieval from specific systems while retaining the full capabilities of each system. The system design includes multi-level capabilities to enhance usability by a wide range of users and utilizes microcomputer graphics capabilities where applicable. A data collection subsystem for evaluation purposes is also described
PC-based Multiple Information System Interface (PC/MISI) detailed design and implementation plan
The design plan for the personal computer multiple information system interface (PC/MISI) project is discussed. The document is intended to be used as a blueprint for the implementation of the system. Each component is described in the detail necessary to allow programmers to implement the system. A description of the system data flow and system file structures is given
PC-based Multiple Information System Interface (PC/MISI) design plan
The general design plan for the implementation of a common user interface to multiple remote information systems within a microcomputer-based environment is presented. The intent is to provide a framework for the development of detailed specifications which will be used as guidelines for the actual development of the system
Gauge Invariant Treatment of the Energy Carried by a Gravitational Wave
Even though the energy carried by a gravitational wave is not itself gauge
invariant, the interaction with a gravitational antenna of the gravitational
wave which carries that energy is. It therefore has to be possible to make some
statements which involve the energy which are in fact gauge invariant, and it
is the objective of this paper to provide them. In order to develop a gauge
invariant treatment of the issues involved, we construct a specific action for
gravitational fluctuations which is gauge invariant to second perturbative
order. Then, via variation of this action, we obtain an energy-momentum tensor
for perturbative gravitational fluctuations around a general curved background
whose covariant conservation condition is also fully gauge invariant to second
order. Contraction of this energy-momentum tensor with a Killing vector of the
background conveniently allows us to convert this covariant conservation
condition into an ordinary conservation condition which is also gauge invariant
through second order. Then, via spatial integration we are able to obtain a
relation involving the time derivative of the total energy of the fluctuation
and its asymptotic spatial momentum flux which is also completely gauge
invariant through second order. It is only in making the simplification of
setting the asymptotic momentum flux to zero that one would actually lose
manifest gauge invariance, with only invariance under those particular gauge
transformations which leave the asymptotic momentum flux zero then remaining.
However, if one works in an arbitrary gauge where the asymptotic momentum flux
is non-zero, the gravitational wave will then deliver both energy and momentum
to a gravitational antenna in a completely gauge invariant manner, no matter
how badly behaved at infinity the gauge function might be.Comment: 13 pages, revtex4. Final version. To appear in Phys. Rev.
Completeness of non-normalizable modes
We establish the completeness of some characteristic sets of non-normalizable
modes by constructing fully localized square steps out of them, with each such
construction expressly displaying the Gibbs phenomenon associated with trying
to use a complete basis of modes to fit functions with discontinuous edges. As
well as being of interest in and of itself, our study is also of interest to
the recently introduced large extra dimension brane-localized gravity program
of Randall and Sundrum, since the particular non-normalizable mode bases that
we consider (specifically the irregular Bessel functions and the associated
Legendre functions of the second kind) are associated with the tensor
gravitational fluctuations which occur in those specific brane worlds in which
the embedding of a maximally four-symmetric brane in a five-dimensional anti-de
Sitter bulk leads to a warp factor which is divergent. Since the brane-world
massless four-dimensional graviton has a divergent wave function in these
particular cases, its resulting lack of normalizability is thus not seen to be
any impediment to its belonging to a complete basis of modes, and consequently
its lack of normalizability should not be seen as a criterion for not including
it in the spectrum of observable modes. Moreover, because the divergent modes
we consider form complete bases, we can even construct propagators out of them
in which these modes appear as poles with residues which are expressly finite.
Thus even though normalizable modes appear in propagators with residues which
are given as their finite normalization constants, non-normalizable modes can
just as equally appear in propagators with finite residues too -- it is just
that such residues will not be associated with bilinear integrals of the modes.Comment: 34 pages, 6 figures. Revte
Dirac Quantization of the Pais-Uhlenbeck Fourth Order Oscillator
As a model, the Pais-Uhlenbeck fourth order oscillator with equation of
motion
is a quantum-mechanical prototype of a field theory containing both second and
fourth order derivative terms. With its dynamical degrees of freedom obeying
constraints due to the presence of higher order time derivatives, the model
cannot be quantized canonically. We thus quantize it using the method of Dirac
constraints to construct the correct quantum-mechanical Hamiltonian for the
system, and find that the Hamiltonian diagonalizes in the positive and negative
norm states that are characteristic of higher derivative field theories.
However, we also find that the oscillator commutation relations become singular
in the limit, a limit which corresponds to a prototype
of a pure fourth order theory. Thus the particle content of the theory cannot be inferred from that of the
theory; and in fact in the limit we find that all of
the negative norm states move off shell, with the
spectrum of asymptotic in and out states of the equal frequency theory being
found to be completely devoid of states with either negative energy or negative
norm. As a byproduct of our work we find a Pais-Uhlenbeck analog of the zero
energy theorem of Boulware, Horowitz and Strominger, and show how in the equal
frequency Pais-Uhlenbeck theory the theorem can be transformed into a positive
energy theorem instead.Comment: RevTeX4, 20 pages. Final version, to appear in Phys. Rev.
THE EFFECTS OF THE MICRO-MARKET STRUCTURE ON ILLINOIS ELEVATOR SPATIAL CORN PRICE DIFFERENTIALS
Corn price differentials among Illinois elevators can often exceed transportation costs. Using primary data, we examine the effects of micro-market structure variables on the differentials in bids prices offered by Illinois elevators. Our findings suggest the existence of a highly developed, responsive market of competing firms, operating in an industry that can be characterized by monopsonistic competition, and to some extent by seasonally induced market power. Local supply conditions, firm productive efficiency, and their operating practices influence price differentials. Further, firm type, final market destination of the grain, and period of the marketing year affect price differentials.Market structure, Corn price differentials, Marketing,
Exact Integration of the High Energy Scale in Doped Mott Insulators
We expand on our earlier work (cond-mat/0612130, Phys. Rev. Lett. {\bf 99},
46404 (2007)) in which we constructed the exact low-energy theory of a doped
Mott insulator by explicitly integrating (rather than projecting) out the
degrees of freedom far away from the chemical potential. The exact low-energy
theory contains degrees of freedom that cannot be obtained from projective
schemes. In particular a new charge bosonic field emerges at low
energies that is not made out of elemental excitations. Such a field accounts
for dynamical spectral weight transfer across the Mott gap. At half-filling, we
show that two such excitations emerge which play a crucial role in preserving
the Luttinger surface along which the single-particle Green function vanishes.
In addition, the interactions with the bosonic fields defeat the artificial
local SU(2) symmetry that is present in the Heisenberg model. We also apply
this method to the Anderson-U impurity and show that in addition to the Kondo
interaction, bosonic degrees of freedom appear as well. Finally, we show that
as a result of the bosonic degree of freedom, the electron at low energies is
in a linear superposition of two excitations--one arising from the standard
projection into the low-energy sector and the other from the binding of a hole
and the boson.Comment: Published veriso
THE ECONOMIC AND ENVIRONMENTAL ASPECTS OF COLORADO'S GOLF INDUSTRY
Community/Rural/Urban Development, Environmental Economics and Policy,
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