6,548 research outputs found

    Phase Diagram Of The Biham-Middleton-Levine Traffic Model In Three Dimensions

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    We study numerically the behavior of the Biham-Middleton-Levine traffic model in three dimensions. Our extensive numerical simulations show that the phase diagram for this model in three dimensions is markedly different from that in one and two dimensions. In addition to the full speed moving as well as the completely jamming phases, whose respective average asymptotic car speeds equal one and zero, we observe an extensive region of car densities ρ\rho with a low but non-zero average asymptotic car speed. The transition from this extensive low average asymptotic car speed region to the completely jamming region is at least second order. We argue that this low speed region is a result of the formation of a spatially-limited-extended percolating cluster. Thus, this low speed phase is present in n>3n > 3 dimensional Biham-Middleton-Levine model as well.Comment: Minor clarifications, 1 figure adde

    Parity Problem With A Cellular Automaton Solution

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    The parity of a bit string of length NN is a global quantity that can be efficiently compute using a global counter in O(N){O} (N) time. But is it possible to find the parity using cellular automata with a set of local rule tables without using any global counter? Here, we report a way to solve this problem using a number of r=1r=1 binary, uniform, parallel and deterministic cellular automata applied in succession for a total of O(N2){O} (N^2) time.Comment: Revtex, 4 pages, final version accepted by Phys.Rev.

    Energy Management for a User Interactive Smart Community: A Stackelberg Game Approach

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    This paper studies a three party energy management problem in a user interactive smart community that consists of a large number of residential units (RUs) with distributed energy resources (DERs), a shared facility controller (SFC) and the main grid. A Stackelberg game is formulated to benefit both the SFC and RUs, in terms of incurred cost and achieved utility respectively, from their energy trading with each other and the grid. The properties of the game are studied and it is shown that there exists a unique Stackelberg equilibrium (SE). A novel algorithm is proposed that can be implemented in a distributed fashion by both RUs and the SFC to reach the SE. The convergence of the algorithm is also proven, and shown to always reach the SE. Numerical examples are used to assess the properties and effectiveness of the proposed scheme.Comment: 6 pages, 4 figure

    Relation Between Quantum Speed Limits And Metrics On U(n)

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    Recently, Chau [Quant. Inform. & Comp. 11, 721 (2011)] found a family of metrics and pseudo-metrics on nn-dimensional unitary operators that can be interpreted as the minimum resources (given by certain tight quantum speed limit bounds) needed to transform one unitary operator to another. This result is closely related to the weighted 1\ell^1-norm on Rn{\mathbb R}^n. Here we generalize this finding by showing that every weighted p\ell^p-norm on Rn{\mathbb R}^n with 1\le p \le \limitingp induces a metric and a pseudo-metric on nn-dimensional unitary operators with quantum information-theoretic meanings related to certain tight quantum speed limit bounds. Besides, we investigate how far the correspondence between the existence of metrics and pseudo-metrics of this type and the quantum speed limits can go.Comment: minor amendments, 6 pages, to appear in J.Phys.

    Feasibility of Using Discriminate Pricing Schemes for Energy Trading in Smart Grid

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    This paper investigates the feasibility of using a discriminate pricing scheme to offset the inconvenience that is experienced by an energy user (EU) in trading its energy with an energy controller in smart grid. The main objective is to encourage EUs with small distributed energy resources (DERs), or with high sensitivity to their inconvenience, to take part in the energy trading via providing incentive to them with relatively higher payment at the same time as reducing the total cost to the energy controller. The proposed scheme is modeled through a two-stage Stackelberg game that describes the energy trading between a shared facility authority (SFA) and EUs in a smart community. A suitable cost function is proposed for the SFA to leverage the generation of discriminate pricing according to the inconvenience experienced by each EU. It is shown that the game has a unique sub-game perfect equilibrium (SPE), under the certain condition at which the SFA's total cost is minimized, and that each EU receives its best utility according to its associated inconvenience for the given price. A backward induction technique is used to derive a closed form expression for the price function at SPE, and thus the dependency of price on an EU's different decision parameters is explained for the studied system. Numerical examples are provided to show the beneficial properties of the proposed scheme.Comment: 7 pages, 4 figures, 3 tables, conference pape

    Analysis of Two-Body Decays of Charmed Baryons Using the Quark-Diagram Scheme

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    We give a general formulation of the quark-diagram scheme for the nonleptonic weak decays of baryons. We apply it to all the decays of the antitriplet and sextet charmed baryons and express their decay amplitudes in terms of the quark-diagram amplitudes. We have also given parametrizations for the effects of final-state interactions. For SU(3) violation effects, we only parametrize those in the horizontal WW-loop quark diagrams whose contributions are solely due to SU(3)-violation effects. In the absence of all these effects, there are many relations among various decay modes. Some of the relations are valid even in the presence of final-state interactions when each decay amplitude in the relation contains only a single phase shift. All these relations provide useful frameworks to compare with future experiments and to find out the effects of final-state interactions and SU(3) symmetry violations.Comment: 28 pages, 20 Tables in landscape form, 4 figures. Main changes are: (i) some errors in the Tables and in the relations between the quark-diagram amplitudes of this paper and those of Ref.[10] are corrected, (ii) improvements are made in the presentation so that comparisons with previous works and what have been done to include SU(3) breaking and final-state interactions are more clearly stated; to appear in the Physical Review

    A Framework for Analyzing Factors Influencing Small to Medium Sized Enterprises (SMEs) Ability to Derive Benefit from the Conduct of Web Based Electronic Commerce (EC) - 34 Australian Case Studies

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    This paper is based on case study research conducted with thirty-four Australian SMEs. It develops a framework for identifying and analysing the factors influencing SMEs ability to derive benefit from conducting web-based EC. Adapting the work of Venkatraman (1994) the paper begins by presenting a model of E-business transformation exploring the relationship between the degree of SME organisational transformation and the potential benefits to be derived from EC. This four phase model is used as a basis for examining the range of internal and external factors that influence SMEs ability to engage in these types of organisational transformations and to derive benefits from EC. The factors are grouped into two categorises: internal and external. From analysis it emerges that depending on their nature, these factors generate inhibiting or enabling forces on an SME’s ability to engage in EC business transformation. More specifically, within any particular phase it is the interaction between these inhibiting/enabling forces that directly influence the ability of an SME to derive benefit from the conduct of web-based EC. Significantly the case study analysis also indicates that where SMEs have already engaged in a high level of EC business transformation (phase 4 Enterprises) their ability to derive further marginal benefit from EC becomes increasingly linked to the nature of factors external to the enterprise

    Implications of Shock Wave Experiments with Precompressed Materials for Giant Planet Interiors

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    This work uses density functional molecular dynamics simulations of fluid helium at high pressure to examine how shock wave experiments with precompressed samples can help characterizing the interior of giant planets. In particular, we analyze how large of a precompression is needed to probe a certain depth in a planet's gas envelope. We find that precompressions of up to 0.1, 1.0, 10, or 100 GPa are needed to characterized 2.5, 5.9, 18, to 63% of Jupiter's envelope by mass.Comment: Submitted As Proceedings Article For The American Physical Society Meeting On Shock Compression Of Condensed Matter, Hawaii, June, 200

    A New Design Method and Half-Step Operation for Ultrasonic Stepping Motors

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    In this paper, a systematic design method and a new half-step operation are proposed for ultrasonic stepping motors (USMs) which are based on the principle of spatially shifted standing vibrations. With emphasis on the combination of the order of vibration mode, the number of spatial phase shifts, the number of electrodes, and the number of simultaneously excited electrodes, the design equations and constraints are newly derived, hence, proposing the design procedure. The finite-element method and impedance measurement are also employed to investigate the vibration of the stator. By borrowing the control idea of electromagnetic stepping motors, the half-step operation is newly applied to this USM so that the step size can be further halved. An 80-step USM is prototyped. The proposed design method and half-step operation are well supported by experimentation.published_or_final_versio
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