2,519 research outputs found
Classification with spectral-spatial-temporal archetypes
There are no author-identified significant results in this report
A Cost Impact Assessment Tool for PFS Logistics Consulting
Response surface methodology (RSM) is used for optimality analysis of the cost parameters in mixed integer linear programming. This optimality analysis goes beyond traditional sensitivity and parametric analysis in allowing investigation of the optimal objective function value response over pre-specified ranges on multiple problem parameters. Design of experiments and least squares regression are used to indicate which cost parameters have the greatest impact on the optimal objective function value total cost-and to approximate the optimal total cost surface over the specified ranges on the parameters. The mixed integer linear programming problems of interest are the large-scale problems in supply chain optimization also known as facility location and allocation problems. Furthermore, this optimality analysis technique applies to optimality analysis of costs or right-hand-side elements in continuous linear programs and optimality analysis of costs in mixed of pure integer linear programs. A system which automates this process for supply chain optimization at PFS Logistics Consulting is also detailed, along with description of its application and impact in their daily operations
Gauge/String-Gravity Duality and Froissart Bound
The gauge/string-gravity duality correspondence opened renewed hope and
possibility to address some of the fundamental and non-perturbative QCD
problems in particle physics, such as hadron spectrum and Regge behavior of the
scattering amplitude at high energies. One of the most fundamental and
long-standing problem is the high energy behavior of total cross-sections.
According to a series of exhaustive tests by the COMPETE group, (1). total
cross-sections have a universal Heisenberg behavior in energy corresponding to
the maximal energy behavior allowed by the Froissart bound, i.e., with and for all reactions,
and (2). the factorization relation among is well satisfied by experiments. I discuss the
recent interesting application of the gauge/string-gravity duality of
correspondence with a deformed background metric so as to break the conformal
symmetry that can lead to the Heisenberg behavior of rising total
cross-sections, and present some preliminary results on the high energy QCD
from Planckian scattering in and black-hole production.Comment: 10 pages, Presented to the Coral Gables Conference 2003, Launching of
BelleE\'poque in High Energy Physics and Cosmology, 17 - 21 December 2003,
Fort Lauderdale, Florid
Nonlocality vs. complementarity: a conservative approach to the information problem
A proposal for resolution of the information paradox is that "nice slice"
states, which have been viewed as providing a sharp argument for information
loss, do not in fact do so as they do not give a fully accurate description of
the quantum state of a black hole. This however leaves an information
*problem*, which is to provide a consistent description of how information
escapes when a black hole evaporates. While a rather extreme form of
nonlocality has been advocated in the form of complementarity, this paper
argues that is not necessary, and more modest nonlocality could solve the
information problem. One possible distinguishing characteristic of scenarios is
the information retention time. The question of whether such nonlocality
implies acausality, and particularly inconsistency, is briefly addressed. The
need for such nonlocality, and its apparent tension with our empirical
observations of local quantum field theory, may be a critical missing piece in
understanding the principles of quantum gravity.Comment: 11 pages of text and figures, + references. v2 minor text. v3 small
revisions to match final journal versio
Warped brane-world compactification with Gauss-Bonnet term
In the Randall-Sundrum (RS) brane-world model a singular delta-function
source is matched by the second derivative of the warp factor. So one should
take possible curvature corrections in the effective action of the RS models in
a Gauss-Bonnet (GB) form. We present a linearized treatment of gravity in the
RS brane-world with the Gauss-Bonnet modification to Einstein gravity. We give
explicit expressions for the Neumann propagator in arbitrary D dimensions and
show that a bulk GB term gives, along with a tower of Kaluza-Klein modes in the
bulk, a massless graviton on the brane, as in the standard RS model. Moreover,
a non-trivial GB coupling can allow a new branch of solutions with finite
Planck scale and no naked bulk singularity, which might be useful to avoid some
of the previously known ``no--go theorems'' for RS brane-world
compactifications.Comment: 23 pages, typos in Secs. 5 & 6 corrected, expanded/published version
(IJMPA
On Pair Creation of Extremal Black Holes and Kaluza-Klein Monopoles
Classical solutions describing charged dilaton black holes accelerating in a
background magnetic field have recently been found. They include the Ernst
metric of the Einstein-Maxwell theory as a special case. We study the extremal
limit of these solutions in detail, both at the classical and quantum levels.
It is shown that near the event horizon, the extremal solutions reduce
precisely to the static extremal black hole solutions. For a particular value
of the dilaton coupling, these extremal black holes are five dimensional
Kaluza-Klein monopoles. The euclidean sections of these solutions can be
interpreted as instantons describing the pair creation of extremal black
holes/Kaluza-Klein monopoles in a magnetic field. The action of these
instantons is calculated and found to agree with the Schwinger result in the
weak field limit. For the euclidean Ernst solution, the action for the extremal
solution differs from that of the previously discussed wormhole instanton by
the Bekenstein-Hawking entropy. However, in many cases quantum corrections
become large in the vicinity of the black hole, and the precise description of
the creation process is unknown.Comment: 45 pages, 5 figures, EFI-93-74, UCSBTH-93-38. (Omitted
acknowledgements added, typos fixed
REAM intensity modulator-enabled 10Gb/s colorless upstream transmission of real-time optical OFDM signals in a single-fiber-based bidirectional PON architecture
Reflective electro-absorption modulation-intensity modulators (REAM-IMs) are utilized, for the first time, to experimentally demonstrate colorless ONUs in single-fiber-based, bidirectional, intensity-modulation and direct-detection (IMDD), optical OFDM PONs (OOFDM-PONs) incorporating 25km SSMFs and OLT-side-seeded CW optical signals. The colorlessness of the REAM-IMs is characterized, based on which optimum REAM-IM operating conditions are identified. In the aforementioned PON architecture, 10Gb/s colorless upstream transmissions of end-to-end realtime OOFDM signals are successfully achieved for various wavelengths within the entire C-band. Over such a wavelength window, corresponding minimum received optical powers at the FEC limit vary in a range as small as <0.5dB. In addition, experimental measurements also indicate that Rayleigh backscattering imposes a 2.8dB optical power penalty on the 10Gb/s over 25km upstream OOFDM signal transmission. Furthermore, making use of on-line adaptive bit and power loading, a linear trade-off between aggregated signal line rate and optical power budget is observed, which shows that, for the present PON system, a 10% reduction in signal line rate can improve the optical power budget by 2.6dB. © 2012 Optical Society of America
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
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