27,721 research outputs found
On Multiobjective Evolution Model
Self-Organized Criticality (SOC) phenomena could have a significant effect on
the dynamics of ecosystems. The Bak-Sneppen (BS) model is a simple and robust
model of biological evolution that exhibits punctuated equilibrium behavior.
Here we will introduce random version of BS model. Also we generalize the
single objective BS model to a multiobjective one.Comment: 6 pages, 5 figure
LEVERAGING SOA IN BANKING SYSTEMS INTEGRATION
There is no doubt that the systems integration is one of the most important and complicated tasks in software filed especially for complex applications like banking systems. Complexity in integrating banking systems often comes from continues changes in both technical and business features provided by them to meet customer needs. Banking systems always come from different software vendors which mean using platforms and different design and architecture patterns, and this for sure adds extra complexity for integrating them. Serviceoriented architecture (SOA) is a promising method in software filed that aims to build or restructure software systems in a manner that makes their maintenance and integration easier. Agility is the most important goal that should be achieved when building and integrating banking systems. Simply, agility is needed to meet market needs quickly and efficiently and SOA is the way that could provide itSOA, SOI, P2P Integration, Web Services, and Legacy Code
Unitarization of Gluon Exchange Amplitudes and Rapidity Gaps at the Tevatron
Rapidity gaps between two hard jets at the Tevatron have been interpreted as
being due to the exchange of two gluons which are in an overall color-singlet
state. We show that this simple picture involves unitarity violating
amplitudes. Unitarizing the gluon exchange amplitude leads to qualitatively
different predictions for the fraction of -channel color singlet exchange
events in forward , or scattering, which better fit Tevatron
data.Comment: 21 pages, Revtex, 7 postscript figures included via epsf.sty.
Compressed postscript file of complete paper also available at
http://pheno.physics.wisc.edu/pub/preprints/1998/madph-98-1024.ps.Z or at
ftp://pheno.physics.wisc.edu/pub/preprints/1998/madph-98-1024.ps.
A preliminary study of factors affecting the calibration stability of the iridium versus iridium-40 percent rhodium thermocouple
An iridium versus iridium-40% rhodium thermocouple was studied. Problems associated with the use of this thermocouple for high temperature applications (up to 2000 C) were investigated. The metallurgical studies included X-ray, macroscopic, resistance, and metallographic studies. The thermocouples in the as-received condition from the manufacturer revealed large amounts of internal stress caused by cold working during manufacturing. The thermocouples also contained a large amount of inhomogeneities and segregations. No phase transformations were observed in the alloy up to 1100 C. It was found that annealing the thermocouple at 1800 C for two hours, and then at 1400 C for 2 to 3 hours yielded a fine grain structure, relieving some of the strains, and making the wire more ductile. It was also found that the above annealing procedure stabilized the thermal emf behavior of the thermocouple for application below 1800 C (an improvement from + or - 1% to + or - 0.02% within the range of the test parameters used)
Dirac Fermions in Inhomogeneous Magnetic Field
We study a confined system of Dirac fermions in the presence of inhomogeneous
magnetic field. Splitting the system into different regions, we determine their
corresponding energy spectrum solutions. We underline their physical properties
by considering the conservation energy where some interesting relations are
obtained. These are used to discuss the reflexion and transmission coefficients
for Dirac fermions and check the probability condition for different cases. We
generalize the obtained results to a system with gap and make some analysis.
After evaluating the current-carrying states, we analyze the Klein paradox and
report interesting discussions.Comment: 28 pages, 15 figures. Version to appear in JP
Generalized Swanson models and their solutions
We analyze a class of non-Hermitian quadratic Hamiltonians, which are of the
form , where are real constants, with , and and are generalized
creation and annihilation operators. Thus these Hamiltonians may be classified
as generalized Swanson models. It is shown that the eigenenergies are real for
a certain range of values of the parameters. A similarity transformation
, mapping the non-Hermitian Hamiltonian to a Hermitian one , is
also obtained. It is shown that and share identical energies. As
explicit examples, the solutions of a couple of models based on the
trigonometric Rosen-Morse I and the hyperbolic Rosen-Morse II type potentials
are obtained. We also study the case when the non-Hermitian Hamiltonian is
symmetric.Comment: 17 page
Pseudo-Hermitian Hamiltonians, indefinite inner product spaces and their symmetries
We extend the definition of generalized parity , charge-conjugation
and time-reversal operators to nondiagonalizable pseudo-Hermitian
Hamiltonians, and we use these generalized operators to describe the full set
of symmetries of a pseudo-Hermitian Hamiltonian according to a fourfold
classification. In particular we show that and are the generators of
the antiunitary symmetries; moreover, a necessary and sufficient condition is
provided for a pseudo-Hermitian Hamiltonian to admit a -reflecting
symmetry which generates the -pseudounitary and the -pseudoantiunitary
symmetries. Finally, a physical example is considered and some hints on the
-unitary evolution of a physical system are also given.Comment: 20 page
Human health risks due to consumption of chemically contaminated fishery products.
A small proportion of fishery products contaminated with appreciable amounts of potentially hazardous inorganic and organic contaminants from natural and environmental sources seem to pose the greatest potential for toxicity to consumers of fishery products in the United States. Health risks due to chemicals (e.g., modest changes in the overall risk of cancer, subtle deficits of neurological development in fetuses and children) are difficult to measure directly in people exposed to low levels. Immunocompetence may increase cancer risk. Inferences about the potential magnitude of these problems must be based on the levels of specific chemical present, observations of human populations and experimental animals exposed to relatively high doses, and theories about the likely mechanisms of action of specific intoxicants and the population distribution of sensitivity of human exposure. Lognormal distributions were found to provide good descriptions of the pattern of variation of contaminant concentrations among different species and geographic areas; this variability offers a solution for reduction of exposure through restricting harvest of aquatic animals from certain sites and by excluding certain species. Available information suggest that risks are not generally of high magnitude; nevertheless, their control will significantly improve public health.(ABSTRACT TRUNCATED AT 250 WORDS
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