Interior point methods specialized to the L∞ fitting problem are surveyed, improved, and compared with the traditional simplex approach. A primal affine-scaling interior point method is presented, completing the affi...
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We introduce a simple mechanism for the evolution of small world networks. Our model is a growing network in which all connections are made locally to geographically nearby sites. Although connections are made purely ...
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We introduce a simple mechanism for the evolution of small world networks. Our model is a growing network in which all connections are made locally to geographically nearby sites. Although connections are made purely locally, network growth leads to stretching of old connections and to high clustering. Our results suggest that the abundance of small world networks in geographically constrained systems is a natural consequence of system growth and local interactions.
A general relation between the phase time (group delay) and the dwell time is derived for relativistic tunneling particles described by the Dirac equation. It is shown that the phase time equals the dwell time plus a ...
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A general relation between the phase time (group delay) and the dwell time is derived for relativistic tunneling particles described by the Dirac equation. It is shown that the phase time equals the dwell time plus a self-interference delay which is a relativistic generalization of previous results.
Narrow band lowpass or highpass digital finite impulse response filters can be synthesized by using extrapolated impulse response techniques to achieve reduced complexity. However, the non-linear optimization problem ...
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Narrow band lowpass or highpass digital finite impulse response filters can be synthesized by using extrapolated impulse response techniques to achieve reduced complexity. However, the non-linear optimization problem of the extrapolated impulse response filters was simplified to a linear programming problem in previous literature leading to suboptimum. In this paper, a semi-infinite programming is proposed to jointly optimize the filter coefficients and the extrapolated scaling factors. A realization structure making use of the coefficient symmetry is also presented. An example taken from literature is included illustrating that the number of multipliers for the resulting filter is less than 65 percent of existing results.
We consider a ring of identical or near-identical coupled periodic oscillators in which the connections have randomly heterogeneous strength. We use the master stability function method to determine the possible patte...
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We consider a ring of identical or near-identical coupled periodic oscillators in which the connections have randomly heterogeneous strength. We use the master stability function method to determine the possible patterns at the desynchronization transition that occurs as the coupling strengths are increased. We demonstrate Anderson localization of the modes of instability and show that such localized instability generates waves of desynchronization that spread to the whole array. Similar results should apply to other networks with regular topology and heterogeneous connection strengths.
Approximating of functions that are specified using imperfect knowledge is one of the central issues of many areas such as machine learning, pattern recognition, data mining, or qualitative reasoning. However, we do n...
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Approximating of functions that are specified using imperfect knowledge is one of the central issues of many areas such as machine learning, pattern recognition, data mining, or qualitative reasoning. However, we do not have yet satisfactory methods for approximation of functions and developed calculi on function approximations. In the paper we discuss a function approximation using the rough set approach. The main difference with the existing approaches in rough set theory is based on modification of the inclusion measure. This makes it possible to overcome some drawbacks of the previously used definitions. For applications it is important to develop rough measures on approximated objects, in particular on function approximations. The modified inclusion measure is also used to define an exemplary measure, i.e., the rough integral.
Δ-modulated feedback control of a linear system introduces nonlinearity into the system through switchings between two input values. It has been found that Δ-modulation gives rise to periodic orbits. The existence o...
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Δ-modulated feedback control of a linear system introduces nonlinearity into the system through switchings between two input values. It has been found that Δ-modulation gives rise to periodic orbits. The existence of periodic points of all orders of Sigma-Delta modulation with “leaky” integration is completely characterized by some interesting groups of polynomials with “sign” coefficients. The results are naturally generalized to Sigma-Delta modulations with multiple delays. Further extensions relate to the existence of periodic points arising from Δ-modulated feedback control of a stable linear system in an arbitrary direction, for which some necessary and sufficient conditions are given.
In this paper a synchronization controller for differential mobile robots is proposed. The synchronization goal is to control the angular position of each wheel to a desired trajectory and at the same time the differe...
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In this paper a synchronization controller for differential mobile robots is proposed. The synchronization goal is to control the angular position of each wheel to a desired trajectory and at the same time the differential (or synchronization) error between the angular position of the two wheels. In this way it is ensured that the mobile robot follows the desired path trajectory with the proper orientation. The controller is based on a computed torque architecture and a set of observers to estimate the angular velocity of the wheels. So that the controller only requires angular position measurements of the wheels.
Time-resolved near-field microscopy allows the propagation of ultrafast pulses to be visualized en route while they travel through complex photonic structures. These measurements enable the unambiguous determination o...
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ISBN:
(纸本)0780383435
Time-resolved near-field microscopy allows the propagation of ultrafast pulses to be visualized en route while they travel through complex photonic structures. These measurements enable the unambiguous determination of both local phase and group velocities. We illustrate this powerful technique by tracking an ultrashort wavepacket as it completes several round trips in a ring resonator.
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