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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Wei-Yong Yan Kok Lay Teo School of Electrical and Computer Engineering Curtin University of Technology Perth WA Australia Department of Applied Mathematics Hong Kong Polytechnic University Hong Kong China

ISBN: (纸本)0780366859

This paper treats the problem of optimal approximation of a given FIR filter by a discrete coefficient FIR filter for fast implementation in hardware. It is shown that the problem can be arbitrarily closely approximated by problems of optimization over a certain smooth compact manifold. Two simple algorithms, which are defined in terms of an ordinary differential equation and a recursive equation, respectively, are derived and guaranteed to be convergent.

关键词： Finite impulse response filter Differential equations Hardware Costs Linear programming Computational modeling Frequency response Australia Design methodology Arithmetic

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Interactions between two-dimensional composite vector solitons carrying topological charges

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Physical Review E 2001年第6期63卷 066608-066608页

作者： Ziad H. Musslimani Marin Soljačić Mordechai Segev Demetrios N. Christodoulides Department of Applied Mathematics University of Colorado Campus Box 526 Boulder Colorado 80309-0526 Department of Physics Massachusetts Institute of Technology Cambridge Massachusetts 02139 Physics Department and Solid State Institute Technion—Israel Institute of Technology 32 000 Haifa IsraelDepartment of Electrical Engineering Princeton University Princeton New Jersey 08544 Department of Electrical Engineering and Computer Science Lehigh University Bethlehem Pennslyvania 18015

We present a comprehensive study of interactions (collisions) between two-dimensional composite vector solitons carrying topological charges in isotropic saturable nonlinear media. We numerically study interactions between such composite solitons for different regimes of collision angle and report numerous effects which are caused solely by the “spin” (topological charge) carried by the second excited mode. The most intriguing phenomenon we find is the delayed-action interaction between interacting composite solitons carrying opposite spins. In this case, two colliding solitons undergo a fusion process and form a metastable bound state that decays after long propagation distances into two or three new solitons. Another noticeable effect is spin-orbit coupling in which angular momentum is being transferred from “spin” to orbital angular momentum. This phenomenon occurs at angles below the critical angle, including the case when the initial soliton trajectories are in parallel to one another and lie in the same plane. Finally, we report on shape transformation of vortex component into a rotating dipole-mode solitons that occurs at large collision angles, i.e., at angles for which scalar solitons of all types simply go through one another unaffected.

关键词： Solitons

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Collisions between (2 + 1)D Composite Solitons: Delayed-Action Interaction and Spin-Orbit Coupling

Collisions between (2 + 1)D Composite Solitons: Delayed-Acti...

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Nonlinear Guided Waves and Their Applications, NLGW 2001

作者： Musslimani, Ziad H. Soljačić, Marin Segev, Mordechai Christodoulides, Demetrios N. Department of Applied Mathematics University of Colorado BoulderCO80309-0526 United States Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States Physics Department The Solid State Institute Technion-Israel Institute of Technology Haifa32 000 Israel Princeton University PrincetonNJ08544 United States Department of Electrical Engineering and Computer Science Lehigh University BethlehemPA United States

ISBN: (纸本)1557526702

关键词： Optical fibers

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Delayed-action interaction between two-dimensional composite solitons

Delayed-action interaction between two-dimensional composite...

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Quantum Electronics and Laser Science Conference, QELS 2001

作者： Musslimani, Z.H. Soljačić, M. Segev, M. Christodoulides, D.N. Department of Applied Mathematics University of Colorado BoulderCO80309-0526 United States Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States Physics Department Solid State Institute Technion - Israel Institute of Technology Haifa32 000 Israel Princeton University PrincetonNJ08544 United States Department of Electrical Engineering and Computer Science Lehigh University BethlehemPA18015 United States

ISBN: (纸本)155752663X

Summary form only given. Soliton interactions are universal, displaying features common to all solitons, in spite of the diversity of the physical systems in which solitons are found. The reason for this universality is the fact that solitons can be viewed as modes of their own induced waveguide. The simplest case arises when the self-induced waveguide has only one mode populated, in which case the soliton is a "scalar soliton". In this vein, collisions of single-mode solitons can be viewed intuitively as interactions between guided modes of adjacent waveguides. In this case, the interaction outcome is determined by the relation between the collision angle and the (complementary) critical angle for total internal reflection in each waveguide, θc. Experimentally, collisions between scalar solitons were studied in detail, demonstrating fully-elastic collisions between Kerr solitons, almost-elastic collisions between solitons in saturable nonlinearities interacting at angles above θc and inelastic collisions that yield fusion, fission, annihilation, and spiraling. © 2001 Optical Soc. Of America.

关键词： Solitons

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Data fusion of three attitude sensors

Data fusion of three attitude sensors

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SICE Annual Conference

作者： Y.T. Chiang F.R. Chang L.S. Wang Y.W. Jan L.H. Ting Department of Electrical Engineering National Taiwan University Taipei Taiwan Institute of Applied machanics National Taiwan University Taipei Taiwan Mechanical Engineering Section NSC National Space Program Office Taiwan

ISBN: (纸本)0780373065

A reliable Spacecraft attitude determination system, which integrate the measurements coming from the star tracker (STR), Global Positioning System (GPS) and gyros, is presented. The linearized state propagation and state update are two key algorithms in the data fusion. For state propagation, the primary information is provided by the high rate (16 Hz) sensors (gyros), whose measurement offsets are calibrated by the integrated filter. For state update, the primary information is provide by the low rate (1 Hz) sensors (STR and GPS). To minimize the update errors, the covariance matrices associated to different sensors are selected as the weightings. From the simulation results, our ideas are verified to be sound and effective.

关键词： Sensor fusion Global Positioning System Acoustic sensors Magnetic sensors Filters Error correction Sensor systems Angular velocity Software performance Costs

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Interpolation formula between very low and intermediate-to-high damping Kramers escape rates for single-domain ferromagnetic particles

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Physical Review E 2001年第2期63卷 021102-021102页

作者： P. M. Déjardin D. S. F. Crothers W. T. Coffey D. J. McCarthy Department of Applied Mathematics and Theoretical Physics David Bates Building The Queen’s University of Belfast Belfast BT7 1NN Northern Ireland United Kingdom Department of Electronics and Electrical Engineering Trinity College Dublin 2 Ireland School of Mathematics Statistics and Computer Science Dublin Institute of Technology Kevin Street Dublin 8 Ireland

It is shown that the Mel’nikov-Meshkov formalism for bridging the very low damping (VLD) and intermediate-to-high damping (IHD) Kramers escape rates as a function of the dissipation parameter for mechanical particles may be extended to the rotational Brownian motion of magnetic dipole moments of single-domain ferromagnetic particles in nonaxially symmetric potentials of the magnetocrystalline anisotropy so that both regimes of damping occur. The procedure is illustrated by considering the particular nonaxially symmetric problem of superparamagnetic particles possessing uniaxial anisotropy subject to an external uniform field applied at an angle to the easy axis of magnetization. Here the Mel’nikov-Meshkov treatment is found to be in good agreement with an exact calculation of the smallest eigenvalue of Brown’s Fokker-Planck equation, provided the external field is large enough to ensure significant departure from axial symmetry, so that the VLD and IHD formulas for escape rates of magnetic dipoles for nonaxially symmetric potentials are valid.

关键词： Ferromagnetic materials

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Optimization of a PMD compensator with constant differential group delay using importance sampling

Optimization of a PMD compensator with constant differential...

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Conference on Lasers and Electro-Optics (CLEO)

作者： I.T. Lima G. Biondini B. Marks W.L. Kath C.R. Menyuk Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD USA Engineering Sciences and Applied Mathematics McCormick School of Engineering and Applied Sciences Northwestern University Evanston IL USA Laboratory for Telecommunication Sciences U.S. ARL Adelphi MD USA

Summary form only given. We have studied first-order polarization-mode dispersion (PMD) compensators with a fixed value of DGD/sub c/. We have shown that the optimal value of DGD/sub c/ for realistic power penalties of 2 dB is 2-3 times larger than (/spl Delta//spl pi/). This optimal value of DGD, actually degrades the average penalty somewhat, but it reduces the outage probability by several orders of magnitude. Our results indicate that it is not sufficient to study the impact of PMD compensators on the average penalty when designing realistic systems. It is crucial to accurately model the tails of the distribution function of the penalties. Importance sampling is a technique that makes this sort of study feasible.

关键词： Delay Monte Carlo methods Clocks Optical distortion Polarization mode dispersion Optical pulse shaping Optical pulses Optical polarization Optical fiber polarization Fiber nonlinear optics

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Accurate calculation of eye diagrams and error rates in long-haul transmission systems

Accurate calculation of eye diagrams and error rates in long...

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Optical Fiber Communication (OFC) Conference

作者： R. Holzlohner C.R. Menyuk V.S. Grigoryan W.L. Kath Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD USA Laboratory for Telecommunications Sciences U.S. ARL Adelphi MD USA Department of Engineering Sciences and Applied Mathematics Northwestern University Evanston IL USA

We found the distribution of phase and timing jitter in a DMS system to be Gaussian-distributed. After their removal, the residual noise Fourier components obey a multivariate-Gaussian distribution, allowing us to acc... 详细信息

ISBN: (纸本)1557526559

关键词： Error analysis Optical noise Timing jitter Gaussian distribution Optical receivers Bit error rate Gaussian noise Histograms Fiber nonlinear optics Optical mixing

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Delayed-action interaction between two-dimensional composite solitons

Delayed-action interaction between two-dimensional composite...

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Quantum Electronics and Laser Science Conference (QELS)

作者： Z.H. Musslimani M. Soljacic M. Segev D.N. Christodoulides Department of Applied Mathematics University of Colorado Boulder CO USA Department of Physics Massachusetts Institute of Technology Cambridge MA USA Physics Department and the Solid State Institute Technion-Israel Institute of Technology Haifa Israel Princeton University Princeton NJ USA Department of Electrical Engineering and Computer Science Lehigh University Bethlehem PA USA

Summary form only given. Soliton interactions are universal, displaying features common to all solitons, in spite of the diversity of the physical systems in which solitons are found. The reason for this universality is the fact that solitons can be viewed as modes of their own induced waveguide. The simplest case arises when the self-induced waveguide has only one mode populated, in which case the soliton is a "scalar soliton". In this vein, collisions of single-mode solitons can be viewed intuitively as interactions between guided modes of adjacent waveguides. In this case, the interaction outcome is determined by the relation between the collision angle and the (complementary) critical angle for total internal reflection in each waveguide, /spl theta//sub c/. Experimentally, collisions between scalar solitons were studied in detail, demonstrating fully-elastic collisions between Kerr solitons, almost-elastic collisions between solitons in saturable nonlinearities interacting at angles above /spl theta//sub c/ and inelastic collisions that yield fusion, fission, annihilation, and spiraling.

关键词： Delay Solitons Physics Marine technology Diffraction mathematics Solid state circuits Veins Reflection Fuses

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Accurate eye diagrams and error rates using linearization

Accurate eye diagrams and error rates using linearization

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European Conference on Optical Communication (ECOC)

作者： R. Holzhlohner C.R. Menyuk V.S. Grigoryan W.L. Kath Dept. of Comput. Sci. & Electr. Eng. Maryland Univ. Baltimore MD USA Laboratory for Telecommunications Sciences U.S. ARL Adelphi MD USA Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD USA Department of Engineering Sciences and Applied Mathematics Northeastern University Evanston IL USA

We find that the signal evolution of a chirped return-to-zero (CRZ) pulse over 6100 km is fully linearizable, and the noise Fourier components are multivariate Gaussian-distributed. We introduce a deterministic method... 详细信息

ISBN: (纸本)0780367057

关键词： Error analysis Optical noise Chirp Optical receivers Timing jitter Bit error rate Pulse amplifiers Spontaneous emission Solitons Covariance matrix

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