79,239 research outputs found
Solvable Lattice Gas Models with Three Phases
Phase boundaries in p-T and p-V diagrams are essential in material science
researches. Exact analytic knowledge about such phase boundaries are known so
far only in two-dimensional (2D) Ising-like models, and only for cases with two
phases. In the present paper we present several lattice gas models, some with
three phases. The phase boundaries are either analytically calculated or
exactly evaluated.Comment: 5 pages, 6 figure
Quark Coalescence with Quark Number Conservation and the Effect on Quark-Hadron Scaling
We develop a new formulation of the quark coalescence model by including the
quark number conservation in order to describe the hadronization of the bulk of
the quark-gluon plasma. The scalings between hadron and quark phase space
distributions are shown to depend on the transverse momentum. For hard quarks,
our general scalings reproduce the usual quadratic scaling relation for mesons
and the cubic scaling relation for baryons. For softer quarks, however, the
inclusion of the quark number conservation leads to a linear scaling for the
hadron species that dominates the quark number of each flavor, while the
scalings of non-dominant hadrons depend on the coalescence dynamics. For charm
mesons, we find that the distribution of soft mesons does not depend on the
light quark distribution but the distribution of soft mesons is
inversely correlated to the light quark distribution.Comment: Added 6 more equations to explain the derivations; added discussions;
final published versio
Error-constrained filtering for a class of nonlinear time-varying delay systems with non-gaussian noises
Copyright [2010] IEEE. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected].
By choosing to view this document, you agree to all provisions of the copyright laws protecting it.In this technical note, the quadratic error-constrained filtering problem is formulated and investigated for discrete time-varying nonlinear systems with state delays and non-Gaussian noises. Both the Lipschitz-like and ellipsoid-bounded nonlinearities are considered. The non-Gaussian noises are assumed to be unknown, bounded, and confined to specified ellipsoidal sets. The aim of the addressed filtering problem is to develop a recursive algorithm based on the semi-definite programme method such that, for the admissible time-delays, nonlinear parameters and external bounded noise disturbances, the quadratic estimation error is not more than a certain optimized upper bound at every time step. The filter parameters are characterized in terms of the solution to a convex optimization problem that can be easily solved by using the semi-definite programme method. A simulation example is exploited to illustrate the effectiveness of the proposed design procedures.This work was supported in part by the Leverhulme Trust of the U.K., the Engineering and Physical Sciences Research Council (EPSRC) of the U.K. under Grant GR/S27658/01, the Royal Society of the
U.K., the National Natural Science Foundation of China under Grant 61028008
and Grant 61074016, the Shanghai Natural Science Foundation of China under Grant 10ZR1421200, and the Alexander von Humboldt Foundation of Germany.
Recommended by Associate Editor E. Fabre
Technical Report: Compressive Temporal Higher Order Cyclostationary Statistics
The application of nonlinear transformations to a cyclostationary signal for
the purpose of revealing hidden periodicities has proven to be useful for
applications requiring signal selectivity and noise tolerance. The fact that
the hidden periodicities, referred to as cyclic moments, are often compressible
in the Fourier domain motivates the use of compressive sensing (CS) as an
efficient acquisition protocol for capturing such signals. In this work, we
consider the class of Temporal Higher Order Cyclostationary Statistics (THOCS)
estimators when CS is used to acquire the cyclostationary signal assuming
compressible cyclic moments in the Fourier domain. We develop a theoretical
framework for estimating THOCS using the low-rate nonuniform sampling protocol
from CS and illustrate the performance of this framework using simulated data
Implicit Smartphone User Authentication with Sensors and Contextual Machine Learning
Authentication of smartphone users is important because a lot of sensitive
data is stored in the smartphone and the smartphone is also used to access
various cloud data and services. However, smartphones are easily stolen or
co-opted by an attacker. Beyond the initial login, it is highly desirable to
re-authenticate end-users who are continuing to access security-critical
services and data. Hence, this paper proposes a novel authentication system for
implicit, continuous authentication of the smartphone user based on behavioral
characteristics, by leveraging the sensors already ubiquitously built into
smartphones. We propose novel context-based authentication models to
differentiate the legitimate smartphone owner versus other users. We
systematically show how to achieve high authentication accuracy with different
design alternatives in sensor and feature selection, machine learning
techniques, context detection and multiple devices. Our system can achieve
excellent authentication performance with 98.1% accuracy with negligible system
overhead and less than 2.4% battery consumption.Comment: Published on the IEEE/IFIP International Conference on Dependable
Systems and Networks (DSN) 2017. arXiv admin note: substantial text overlap
with arXiv:1703.0352
MEMS On/off and x2 Optical Switch with Integrated Fiber Alignment Capability
An on/off free space optical switch is described in this paper. The device consists of intersecting cantilevers and is electrostatically actuated. A fiber is put onto the cantilevers and by controlling the position of the flber
through actuation, switching operation can be achieved. The device is also suitable for inpackage fiber alignment application, where the cantilevers can be used as passive or active fiber alignment microstructure
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