We present a simple adaptation of the Lempel Ziv 78' (LZ78) compression scheme that supports efficient random access to the input string. The compression algorithm is given as input a parameter ε > 0, and with...
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ISBN:
(纸本)9781467360371
We present a simple adaptation of the Lempel Ziv 78' (LZ78) compression scheme that supports efficient random access to the input string. The compression algorithm is given as input a parameter ε > 0, and with very high probability increases the length of the compressed string by at most a factor of (1 + ε). The access time is O(log n + 1/ε 2 ) in expectation, and O(log n/ε 2 ) with high probability. The scheme relies on sparse transitive-closure spanners. Any (consecutive) substring of the input string can be retrieved at an additional additive cost in the running time of the length of the substring. The main benefit of the proposed scheme is that it preserves the online nature and simplicity of LZ78, and that for every input string, the length of the compressed string is only a small factor larger than that obtained by running LZ78.
In this paper, a cepstral analysis based approach to measuring the depth of anesthesia (DoA) is presented. Cepstral analysis is a signal processing technique widely used especially for speech recognition in order to e...
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ISBN:
(纸本)9781457702150
In this paper, a cepstral analysis based approach to measuring the depth of anesthesia (DoA) is presented. Cepstral analysis is a signal processing technique widely used especially for speech recognition in order to extract speech information regardless of vocal cord characteristics. The resulting index for the DoA is called index based on cepstral analysis (ICep). The Fisher criterion is engaged to evaluate the performance of indices. All analyses are based on a single-channel electroencephalogram (EEG) of 10 human subjects. To validate the proposed technique, ICep is compared with bispectral index (BIS), which is the most commonly used method to estimate the level of consciousness via EEG during general anesthesia. The results show that ICep has high correlation with BIS, and is outstanding in terms of the Fisher criterion and offers faster tracking than BIS in the transition from consciousness to unconsciousness.
DC faults may cause severe disruptions in continuity of service to vital loads in a shipboard integrated power system, hence detection, isolation, and protection against such faults must be incorporated in both medium...
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DC faults may cause severe disruptions in continuity of service to vital loads in a shipboard integrated power system, hence detection, isolation, and protection against such faults must be incorporated in both medium-voltage DC (MVDC) and low-voltage DC (LVDC) systems. Here we consider the effectiveness of existing z-source breakers and propose several new designs more appropriate for fault detection in MVDC and LVDC systems. In particular, we perform an optimization study that aims to minimize dissipation and weight and we identify the key parameters for use in MVDC and LVDC systems. Preliminary verification and validation studies are also included.
The magnetic vortex dynamics in thickness-modulated Ni80Fe20 disks in the form of a Ni80Fe20 lens on top of a Ni80Fe20 disk are investigated. The vortex core location can be systematically controlled via the geometry,...
The magnetic vortex dynamics in thickness-modulated Ni80Fe20 disks in the form of a Ni80Fe20 lens on top of a Ni80Fe20 disk are investigated. The vortex core location can be systematically controlled via the geometry, and the propagation and annihilation can be detected using ferromagnetic resonance measurements. The thickness modulation provides an additional shape anisotropy, which defines the vortex chirality in the disk depending on the magnetization reversal history and the magnetic interactions between the disk and the lens. The vortex propagation and annihilation in each layer were identified by their resonance modes.
We present compressive sensing techniques to overcome the challenge of sampling the fourdimensional (4D) mutual intensity function, thus recovering complete information about the second-order statistical properties of...
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A thin-film nanostructured Lüneburg lens with guidance condition correction has been fabricated by patterning a slab of silicon-rods on silicon-on-insulator wafer, and has been characterized using a near-field sc...
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A thin-film nanostructured Lüneburg lens with guidance condition correction has been fabricated by patterning a slab of silicon-rods on silicon-on-insulator wafer, and has been characterized using a near-field scanning optical microscope.
We consider electroconvective fluid flows initiated by ion concentration polarization (ICP) under pressure-driven shear flow, a scenario often found in many electrochemical devices and systems. Combining scaling analy...
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We consider electroconvective fluid flows initiated by ion concentration polarization (ICP) under pressure-driven shear flow, a scenario often found in many electrochemical devices and systems. Combining scaling analysis, experiment, and numerical modeling, we reveal unique behaviors of ICP under shear flow: a unidirectional vortex structure, its height selection, and vortex advection. Determined by both the external pressure gradient and the electric body force, the dimensionless height of the sheared electroconvective vortex is shown to scale as (ϕ2/UHP)1/3, which is a clear departure from the previous diffusion-drift model prediction. To the best of our knowledge, this is the first microscopic characterization of ion concentration polarization under shear flow, and it firmly establishes electroconvection as the mechanism for an overlimiting current in realistic, large-area ion exchange membrane systems such as electrodialysis. The new scaling law has significant implications on the optimization of electrodialysis and other electrochemical systems.
It is demonstrated that codewords of good codes for the additive white Gaussian noise (AWGN) channel become more and more isotropically distributed (in the sense of evaluating quadratic forms) and resemble white Gauss...
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Recently Tchamkerten et al. proposed a mathematical formulation of the problem of joint synchronization and error-correction in noisy channels. A variation of their formulation in this paper considers a strengthened r...
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We study the problem of relay design and placement for On-Off Keying signals. We assume that the relay is memoryless and consider both, coherent and non-coherent devices. We derive the optimal coherent relay and compa...
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