2,035,657 research outputs found
Matter-antimatter coexistence method for finite density QCD toward a solution of the sign problem
Toward the lattice QCD calculation at finite density, we propose
"matter-antimatter coexistence method", where matter and anti-matter systems
are prepared on two parallel -sheets in five-dimensional Euclidean
space-time. We put a matter system with a chemical potential on a -sheet, and also put an anti-matter system with
on the other -sheet shifted in the fifth direction. Between
the gauge variables in and in , we introduce a correlation term with a real
parameter . In one limit of , a strong
constraint is realized, and therefore the total
fermionic determinant becomes real and non-negative, due to the cancellation of
the phase factors in and , although this system resembles QCD with
an isospin chemical potential. In another limit of ,
this system goes to two separated ordinary QCD systems with the chemical
potential of and . For a given finite-volume lattice, if one
takes an enough large value of , is
realized and phase cancellation approximately occurs between two fermionic
determinants in and , which suppresses the sign problem and is
expected to make the lattice calculation possible. For the obtained gauge
configurations of the coexistence system, matter-side quantities are evaluated
through their measurement only for the matter part . The physical quantities
in finite density QCD are expected to be estimated by the calculations with
gradually decreasing and the extrapolation to . We also
consider more sophisticated improvement of this method using an irrelevant-type
correlation.Comment: 4 page
A Max-Plus Model of Asynchronous Cellular Automata
This paper presents a new framework for asynchrony. This has its origins in
our attempts to better harness the internal decision making process of cellular
automata (CA). Thus, we show that a max-plus algebraic model of asynchrony
arises naturally from the CA requirement that a cell receives the state of each
neighbour before updating. The significant result is the existence of a
bijective mapping between the asynchronous system and the synchronous system
classically used to update cellular automata. Consequently, although the CA
outputs look qualitatively different, when surveyed on "contours" of real time,
the asynchronous CA replicates the synchronous CA. Moreover, this type of
asynchrony is simple - it is characterised by the underlying network structure
of the cells, and long-term behaviour is deterministic and periodic due to the
linearity of max-plus algebra. The findings lead us to proffer max-plus algebra
as: (i) a more accurate and efficient underlying timing mechanism for models of
patterns seen in nature, and (ii) a foundation for promising extensions and
applications.Comment: in Complex Systems (Complex Systems Publications Inc), Volume 23,
Issue 4, 201
Real-time bladder volume monitoring by the application of a new implantable bladder volume sensor for a small animal model
AbstractAlthough real-time monitoring of bladder volume together with intravesical pressure can provide more information for understanding the functional changes of the urinary bladder, it still entails difficulties in the accurate prediction of real-time bladder volume in urodynamic studies with small animal models. We studied a new implantable bladder volume monitoring device with eight rats. During cystometry, microelectrodes prepared by the microelectromechanical systems process were placed symmetrically on both lateral walls of the bladder, and the expanded bladder volume was calculated. Immunohistological study was done after 1 week and after 4 weeks to evaluate the biocompatibility of the microelectrode. From the point that infused saline volume into the bladder was higher than 0.6mL, estimated bladder volume was statistically correlated with the volume of saline injected (p<0.01). Additionally, the microelectromechanical system microelectrodes used in this study showed reliable biocompatibility. Therefore, the device can be used to evaluate changes in bladder volume in studies with small animals, and it may help to provide more information about functional changes in the bladder in laboratory studies. Furthermore, owing to its biocompatibility, the device could be chronically implanted in conscious ambulating animals, thus allowing a novel longitudinal study to be performed for a specific purpose
A probabilistic approach for modeling and real-time filtering of freeway detector data
Traffic surveillance systems are a key component for providing information on traffic conditions and supporting traffic management functions. A large amount of data is currently collected from inductive loop detector systems in the form of three macroscopic traffic parameters (speed, volume and occupancy). Such information is vital to the successful implementation of transportation data warehouses and decision support systems. The quality of data is, however, affected by erroneous observations that result from malfunctioning or mis-calibration of detectors. The open literature shows that little effort has been made to establish procedures for screening traffic observations in real-time. This study presents a probabilistic approach for modeling and real-time screening of freeway traffic data. The study proposes a simple methodology to capture the probabilistic and dynamic relationships between the three traffic parameters using historical data collected from the I-4 corridor in Orlando, Florida. The developed models are then used to identify the probability that each traffic observation is partially or fully invalid
Matter-Antimatter Coexistence Method for Finite Density QCD
We propose a "matter-antimatter coexistence method" for finite-density
lattice QCD, aiming at a possible solution of the sign problem. In this method,
we consider matter and anti-matter systems on two parallel -sheets
in five-dimensional Euclidean space-time. For the matter system with a
chemical potential on a -sheet, we also prepare
the anti-matter system with on the other -sheet
shifted in the fifth direction. In the lattice QCD formalism, we introduce a
correlation term between the gauge variables in
and in , such as with a real parameter . In the limit of , a strong constraint is
realized, and the total fermionic determinant is real and non-negative. In the
limit of , this system goes to two separated ordinary
QCD systems with the chemical potential of and . On a
finite-volume lattice, if one takes an enough large value of , is realized and there occurs a phase cancellation
approximately between two fermionic determinants in and , which is
expected to suppress the sign problem and to make the lattice calculation
possible. For the obtained gauge configurations of the coexistence system,
matter-side quantities are evaluated through their measurement only for the
matter part . By the calculations with gradually decreasing and
their extrapolation to , physical quantities in finite density QCD
are expected to be estimated.Comment: 6 pages, 1 figure. arXiv admin note: substantial text overlap with
arXiv:1705.0751
Finite-Size Effects on Return Interval Distributions for Weakest-Link-Scaling Systems
The Weibull distribution is a commonly used model for the strength of brittle
materials and earthquake return intervals. Deviations from Weibull scaling,
however, have been observed in earthquake return intervals and in the fracture
strength of quasi-brittle materials. We investigate weakest-link scaling in
finite-size systems and deviations of empirical return interval distributions
from the Weibull distribution function. We use the ansatz that the survival
probability function of a system with complex interactions among its units can
be expressed as the product of the survival probability functions for an
ensemble of representative volume elements (RVEs). We show that if the system
comprises a finite number of RVEs, it obeys the -Weibull distribution.
We conduct statistical analysis of experimental data and simulations that show
good agreement with the -Weibull distribution. We show the following:
(1) The weakest-link theory for finite-size systems involves the
-Weibull distribution. (2) The power-law decline of the
-Weibull upper tail can explain deviations from the Weibull scaling
observed in return interval data. (3) The hazard rate function of the
-Weibull distribution decreases linearly after a waiting time , where is the Weibull modulus and is the system size
in terms of representative volume elements. (4) The -Weibull provides
competitive fits to the return interval distributions of seismic data and of
avalanches in a fiber bundle model. In conclusion, using theoretical and
statistical analysis of real and simulated data, we show that the
-Weibull distribution is a useful model for extreme-event return
intervals in finite-size systems.Comment: 33 pages, 11 figure
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