835 research outputs found
An extensible product structure model for product lifecycle management in the make-to-order environment
This paper presents a product structure model with a semantic representation technique that make the product structure extensible for developing product lifecycle management (PLM) systems that is flexible for make-to-order environment. In the make-to-order business context, each product could have a number of variants with slightly different constitutions to fulfill different customer requirements. All the variants of a family have common characteristics and each variant has its specific features. A master-variant pattern is proposed for building the product structure model to explicitly represent common characteristics and specific features of individual variants. The model is capable of enforcing the consistency of a family structure and its variant structure, supporting multiple product views, and facilitating the business processes. A semantic representation technique is developed that enables entity attributes to be defined and entities to be categorized in a neutral and semantic format. As a result, entity attributes and entity categorization can be redefined easily with its configurable capability for different requirements of the PLM systems. An XML-based language is developed for semantically representing entities and entity categories. A prototype as a proof-of-concept system is presented to illustrate the capability of the proposed extensible product structure model
Friedmann Equation and Stability of Inflationary Higher Derivative Gravity
Stability analysis on the De Sitter universe in pure gravity theory is known
to be useful in many aspects. We first show how to complete the proof of an
earlier argument based on a redundant field equation. It is shown further that
the stability condition applies to Friedmann-Robertson-Walker spaces
based on the non-redundant Friedmann equation derived from a simple effective
Lagrangian. We show how to derive this expression for the Friedmann equation of
pure gravity theory. This expression is also generalized to include scalar
field interactions.Comment: Revtex, 6 pages, Add two more references, some typos correcte
Time dependent action in potential
The false vacuum decay in field theory from a coherently oscillating initial
state is studied for potential. An oscillating bubble solution is
obtained. The instantaneous bubble nucleation rate is calculated.Comment: 15 pages, Accepted for publication in Communications in Theoretical
Physics. arXiv admin note: text overlap with arXiv:hep-th/960415
Verifying a border array in linear time
A border of a string x is a proper (but possibly empty) prefix of x that is also a suffix of x. The border array β = β[1..n] of a string x = x[1..n] is an array of nonnegative integers in which each element β[i], 1 ≤ i ≤ n, is the length of the longest border of x[1..i]. In this paper we first present a simple linear-time algorithm to determine whether or not a given array y = y[1..n] of integers is a border array of some string on an alphabet of unbounded size. We state as an open problem the design of a corresponding and equally efficient algorithm on an alphabet of bounded size α. We then consider the problem of generating all possible distinct border arrays of given length n on a bounded or unbounded alphabet, and doing so in time proportional to the number of arrays generated. A previously published algorithm that claims to solve this problem in constant time per array generated is shown to be incorrect, and new algorithms are proposed. We state as open the design of an equally efficient on-line algorithm for this problem
Low energy and dynamical properties of a single hole in the t-Jz model
We review in details a recently proposed technique to extract information
about dynamical correlation functions of many-body hamiltonians with a few
Lanczos iterations and without the limitation of finite size. We apply this
technique to understand the low energy properties and the dynamical spectral
weight of a simple model describing the motion of a single hole in a quantum
antiferromagnet: the model in two spatial dimension and for a double
chain lattice. The simplicity of the model allows us a well controlled
numerical solution, especially for the two chain case. Contrary to previous
approximations we have found that the single hole ground state in the infinite
system is continuously connected with the Nagaoka fully polarized state for
. Analogously we have obtained an accurate determination of the
dynamical spectral weight relevant for photoemission experiments. For
an argument is given that the spectral weight vanishes at the Nagaoka energy
faster than any power law, as supported also by a clear numerical evidence. It
is also shown that spin charge decoupling is an exact property for a single
hole in the Bethe lattice but does not apply to the more realistic lattices
where the hole can describe closed loop paths.Comment: RevTex 3.0, 40 pages + 16 Figures in one file self-extracting, to
appear in Phys. Rev
Anomalous Effects of "Guest" Charges Immersed in Electrolyte: Exact 2D Results
We study physical situations when one or two "guest" arbitrarily-charged
particles are immersed in the bulk of a classical electrolyte modelled by a
Coulomb gas of positive/negative unit point-like charges, the whole system
being in thermal equilibrium. The models are treated as two-dimensional with
logarithmic pairwise interactions among charged constituents; the
(dimensionless) inverse temperature is considered to be smaller than 2
in order to ensure the stability of the electrolyte against the collapse of
positive-negative pairs of charges. Based on recent progress in the integrable
(1+1)-dimensional sine-Gordon theory, exact formulas are derived for the
chemical potential of one guest charge and for the asymptotic large-distance
behavior of the effective interaction between two guest charges. The exact
results imply, under certain circumstances, anomalous effects such as an
effective attraction (repulsion) between like-charged (oppositely-charged)
guest particles and the charge inversion in the electrolyte vicinity of a
highly-charged guest particle. The adequacy of the concept of renormalized
charge is confirmed in the whole stability region of inverse temperatures and
the related saturation phenomenon is revised.Comment: 21 pages, 1 figur
Measurements of the Mass and Full-Width of the Meson
In a sample of 58 million events collected with the BES II detector,
the process J/ is observed in five different decay
channels: , , (with ), (with
) and . From a combined fit of all five
channels, we determine the mass and full-width of to be
MeV/ and
MeV/.Comment: 9 pages, 2 figures and 4 table. Submitted to Phys. Lett.
A Measurement of Psi(2S) Resonance Parameters
Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been
measured in the vicinity of the Psi(2S) resonance using the BESII detector
operated at the BEPC. The Psi(2S) total width; partial widths to hadrons,
pi+pi- J/Psi, muons; and corresponding branching fractions have been determined
to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)=
(2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)=
(97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%,
respectively.Comment: 8 pages, 6 figure
Measurements of the observed cross sections for exclusive light hadrons containing at , 3.650 and 3.6648 GeV
By analyzing the data sets of 17.3, 6.5 and 1.0 pb taken,
respectively, at , 3.650 and 3.6648 GeV with the BES-II
detector at the BEPC collider, we measure the observed cross sections for
, , ,
and at the three energy
points. Based on these cross sections we set the upper limits on the observed
cross sections and the branching fractions for decay into these
final states at 90% C.L..Comment: 7 pages, 2 figure
Study of J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar
The branching ratios and Angular distributions for J/psi decays to Lambda
Lambdabar and Sigma0 Sigma0bar are measured using BESII 58 million J/psi.Comment: 11 pages, 5 figure
- …