31 research outputs found
Multi-Species Asymmetric Exclusion Process in Ordered Sequential Update
A multi-species generalization of the asymmetric simple exclusion process
(ASEP) is studied in ordered sequential and sub-lattice parallel updating
schemes. In this model particles hop with their own specific probabilities to
their rightmost empty site and fast particles overtake slow ones with a
definite probability. Using Matrix Product Ansatz (MPA), we obtain the relevant
algebra, and study the uncorrelated stationary state of the model both for an
open system and on a ring. A complete comparison between the physical results
in these updates and those of random sequential introduced in [20,21] is made.Comment: Latex file 36 pages with 10 EPS figure
Characteristics of Vehicular Traffic Flow at a Roundabout
We construct a stochastic cellular automata model for the description of
vehicular traffic at a roundabout designed at the intersection of two
perpendicular streets. The vehicular traffic is controlled by a self-organized
scheme in which traffic lights are absent. This controlling method incorporates
a yield-at-entry strategy for the approaching vehicles to the circulating
traffic flow in the roundabout. Vehicular dynamics is simulated within the
framework of the probabilistic cellular automata and the delay experienced by
the traffic at each individual street is evaluated for specified time
intervals. We discuss the impact of the geometrical properties of the
roundabout on the total delay. We compare our results with traffic-light
signalisation schemes, and obtain the critical traffic volume over which the
intersection is optimally controlled through traffic light signalisation
schemes.Comment: 10 pages, 17 eps figures. arXiv admin note: text overlap with
arXiv:cond-mat/040107
Intelligent Controlling Simulation of Traffic Flow in a Small City Network
We propose a two dimensional probabilistic cellular automata for the
description of traffic flow in a small city network composed of two
intersections. The traffic in the network is controlled by a set of traffic
lights which can be operated both in fixed-time and a traffic responsive
manner. Vehicular dynamics is simulated and the total delay experienced by the
traffic is evaluated within specified time intervals. We investigate both
decentralized and centralized traffic responsive schemes and in particular
discuss the implementation of the {\it green-wave} strategy. Our investigations
prove that the network delay strongly depends on the signalisation strategy. We
show that in some traffic conditions, the application of the green-wave scheme
may destructively lead to the increment of the global delay.Comment: 8 pages, 10 eps figures, Revte
Partially Asymmetric Simple Exclusion Model in the Presence of an Impurity on a Ring
We study a generalized two-species model on a ring. The original model [1]
describes ordinary particles hopping exclusively in one direction in the
presence of an impurity. The impurity hops with a rate different from that of
ordinary particles and can be overtaken by them. Here we let the ordinary
particles hop also backward with the rate q. Using Matrix Product Ansatz (MPA),
we obtain the relevant quadratic algebra. A finite dimensional representation
of this algebra enables us to compute the stationary bulk density of the
ordinary particles, as well as the speed of impurity on a set of special
surfaces of the parameter space. We will obtain the phase structure of this
model in the accessible region and show how the phase structure of the original
model is modified. In the infinite-volume limit this model presents a shock in
one of its phases.Comment: Adding more references and doing minor corrections, 16 pages and 3
Eps figure
Rational design of hypoallergenic vaccines: Blocking ige-binding to polcalcin using allergen-specific igg antibodies
Chenopodium album polcalcin (Che a 3) is characterized as a major cause of cross-reactivity inallergic patients to the Chenopodiaceae family. Therefore, the present study was conducted to develop a hypoallergenic Che a 3 derivatives as the candidate vaccine for type 1 allergy. Four derivatives were generated from Che a 3. The first was a mosaic peptide derivative computationally identified in Che a 3 which was coupled to keyhole limpet hemocyanin (KLH). The second one was a mutant Che a 3, and the other two derivatives included N-and C-Terminal halves of Che a 3 that both coupled to KLH. The IgE-binding capacity of Che a 3 and its derivatives and also their ability to induce there combinant Che a 3 (rChe a 3)-specific IgG antibody, were determined using the enzyme-linked immune sorbent assay (ELISA). Moreover, the lymphopro liferative capacity of rChe a 3 or its derivatives and their pro-inflammatory cytokine response interleukin (IL)-5 and IL-13 were measured in the human peripheral blood mononuclear cells (PBMCs). Among all derivatives, the N-Terminal half peptide and mosaic peptide exhibited the lowest IgEbinding capacity. In addition, in comparison to other antigens, KLH-coupled mosaic peptide induced the highest level of the recombinant Che a 3 (rChe a 3)-specific IgG antibody and ther Che a 3 specific-blocking IgG antibody in mice. Moreover, the mosaic peptide lacked lymphopro liferative capacity and down-regulated expression of pro-Allergic IL-5 and IL-13 cytokines. Therefore, a peptide-carrier fusion vaccine, composed of the B-cell epitope coupled to the carrier, could be considered as one of the promising hypoallergenic vaccines to treat patients with allergy to low molecular weight allergens such as Che
Optimised Traffic Flow at a Single Intersection: Traffic Responsive signalisation
We propose a stochastic model for the intersection of two urban streets. The
vehicular traffic at the intersection is controlled by a set of traffic lights
which can be operated subject to fix-time as well as traffic adaptive schemes.
Vehicular dynamics is simulated within the framework of the probabilistic
cellular automata and the delay experienced by the traffic at each individual
street is evaluated for specified time intervals. Minimising the total delay of
both streets gives rise to the optimum signalisation of traffic lights. We
propose some traffic responsive signalisation algorithms which are based on the
concept of cut-off queue length and cut-off density.Comment: 10 pages, 11 eps figs, to appear in J. Phys.
Exact solution of an exclusion process with three classes of particles and vacancies
We present an exact solution for an asymmetric exclusion process on a ring
with three classes of particles and vacancies. Using a matrix product Ansatz,
we find explicit expressions for the weights of the configurations in the
stationary state. The solution involves tensor products of quadratic algebras.Comment: 18 pages, no figures, LaTe
Vehicular traffic flow at an intersection with the possibility of turning
We have developed a Nagel-Schreckenberg cellular automata model for
describing of vehicular traffic flow at a single intersection. A set of traffic
lights operating in fixed-time scheme controls the traffic flow. Open boundary
condition is applied to the streets each of which conduct a uni-directional
flow. Streets are single-lane and cars can turn upon reaching to the
intersection with prescribed probabilities. Extensive Monte Carlo simulations
are carried out to find the model flow characteristics. In particular, we
investigate the flows dependence on the signalisation parameters, turning
probabilities and input rates. It is shown that for each set of parameters,
there exist a plateau region inside which the total outflow from the
intersection remains almost constant. We also compute total waiting time of
vehicles per cycle behind red lights for various control parameters.Comment: 8 pages, 17 eps figures, Late
A sufficient criterion for integrability of stochastic many-body dynamics and quantum spin chains
We propose a dynamical matrix product ansatz describing the stochastic
dynamics of two species of particles with excluded-volume interaction and the
quantum mechanics of the associated quantum spin chains respectively. Analyzing
consistency of the time-dependent algebra which is obtained from the action of
the corresponding Markov generator, we obtain sufficient conditions on the
hopping rates for identifing the integrable models. From the dynamical algebra
we construct the quadratic algebra of Zamolodchikov type, associativity of
which is a Yang Baxter equation. The Bethe ansatz equations for the spectra are
obtained directly from the dynamical matrix product ansatz.Comment: 19 pages Late
Exact stationary state for a deterministic high speed traffic model with open boundaries
An exact solution for a high speed deterministic traffic model with open
boundaries and synchronous update rule is presented. Because of the strong
correlations in the model, the qualitative structure of the stationary state
can be described for general values of the maximum speed. It is shown in the
case of that a detailed analysis of this structure leads to an
exact solution. Explicit expressions for the stationary state probabilities are
given in terms of products of matrices. From this solution an
exact expression for the correlation length is derived.Comment: 20 pages, LaTeX, typos corrected and references adde