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1991 Data Compression Conference, DCC 1991

作者： Sheinwald, Dafna Lempel, Abraham Ziv, Jacob Scientific Center IBM Israel Technion City Haifa32000 Israel Computer Sciense Dept. Technion Israel Inst. of Technology Haifa32000 Israel Electrical Engineering Dept. Technion Israel Inst. of Technology Haifa32000 Israel

ISBN: (纸本)0818692022

Ziv and Lempel QZL78] investigated the encoding power of the class of finite state machines with respect to given individual sequences. In [I.Z86] they extended the model by adding a moving reading head, yielding a finite state model for image encoders. The power of these encoders with respect to given individual images was examined in [LZ86] and [SLZ90]. Motivated by the study of various kinds of machines as recognizers of formal languages, (cf. [HU79]), we compare the encoding and decoding power of finite state sequential machines and the following extensions thereof. First, we show that, with a forward moving head, the best compression achievable for a given sequence, to be decoded by a finite state decoder, is the same as the bcsl ratio attainable for that sequence when encoded by a finite state information lossless encoder. Second of prove that we can not gain in compression by allowing n finite state encoder move its head back and forth on an input sequence, even if the decoder has unrestricted power. However, better compression can be achieved for specific infinite sequences using an unrestricted encoder and a two-way finite state decoder. © 1991 IEEE.

关键词： Formal languages

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On using cad models to compute the pose of curved 3D objects

On using cad models to compute the pose of curved 3D objects

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1991 Workshop on Directions in Automated CAD-Based Vision, CADVIS 1991

作者： Ponce, Jean Hoogs, Anthony Kriegman, David J. Beckman Institute Dept. of Computer Science University of Illinois UrbanaIL61801 United States General Electric Aerospace Military and Data Systems Operations PhiladelphiaPA19101 United States Center for Systems Science Dept. of Electrical Engineering Yale University New HavenCT06520 United States

ISBN: (纸本)0818621478

A new approach is presented for explicitly relating image observables to models of curved three-dimensional objects. This relationship is used for object recognition and positioning. Object models consist of collections of parametric surface patches. The image observables considered are raw range data, surface normals and Gaussian curvature, raw image contours, contour orientation and curvature, raw image intensity, and intensity gradient. Elimination theory provides a method for constructing an implicit equation that relates these observables to the three-dimensional position and orientation of object models. Determining the unknown parameters is reduced to a fitting problem between the implicit equation and the observed data points. A preliminary implementation is presented. © 1991 Proceedings - Workshop on Directions in Automated CAD-Based Vision, CADVIS 1991. All rights reserved.

关键词： Object recognition

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An asymptotic singular value decomposition analysis of nonlinear multilayer neural networks

An asymptotic singular value decomposition analysis of nonli...

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International Joint Conference on Neural Networks (IJCNN)

作者： S.D.D. Goggin K.E. Gustafson K.M. Johnson Optoelectronic Computing Systems Center and Department of Electrical and Computer Engineering University of Colorado Boulder Boulder CO USA Dept. of Electr. & Comput. Eng. Colorado Univ. Boulder CO USA

The nonlinear multilayer neural network architecture is analyzed as a set of coupled Moore-Penrose pseudo-inverse equations, which arise from an asymptotic approximation to each unit's output equation. A linear analysis of these equations is performed through singular value decomposition (SVD) of the input matrix and a matrix of the desired hidden values. This analysis exactly determines the values of the weights and the optimal number of hidden units needed for a given set of training patterns. The outputs of the resulting neural network asymptotically approach the desired output values for each input pattern. This analysis provides an approach to determining the computational complexity of constructing nonlinear feedforward neural networks. A simple example of the XOR problem illustrates the results of the analysis.< >

关键词： Singular value decomposition Neural networks Nonlinear equations Multi-layer neural network Matrix decomposition Couplings Performance analysis Pattern analysis Computational complexity Feedforward neural networks

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An immersible relative saturation moisture sensor with application to transformer oil

An immersible relative saturation moisture sensor with appli...

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International Conference on Properties and Applications of Properties and Applications of Dielectric Materials

作者： P.A. von Guggenberg J.R. Melcher Department of Electrical Engineering and Computer Science Laboratory for Electromagnetic and Electronic Systems Massachusetts Institute of Technology Cambridge MA USA Dept. of Electr. Eng. & Comput. Sci. MIT Cambridge MA USA

Two polyimide-based capacitive humidity sensors were calibrated in Shell Diala A transformer oil and 10 cSt silicone oil at 35, 50, and 70 degrees C. The moisture content of the oils was found to be a linear function of the output voltage with the slope increasing with temperature. Thus, the sensitivity of the sensors to changes in the absolute moisture content of the oils was found to decrease with increasing temperature. For transformer oil the sensitivity changed from 30 mV/p.p.m. at 35 degrees C to 9 mV/p.p.m. at 70 degrees C; for silicone oil the sensitivity changed from 10 mV/p.p.m. at 35 degrees C to 4 mV/p.p.m. at 70 degrees C. Normalization of the absolute moisture content to the saturation level of moisture in the oil for all three calibration temperatures and both oils demonstrated that the sensors respond to the relative saturation of moisture in the oil. The saturation level of moisture in the oils was measured for the three calibration temperatures and could be expressed in Arrhenius form with an activation energy of 0.317 eV for transformer oil and 0.231 eV for silicone oil.< >

关键词： Oil insulation Petroleum Temperature sensors Power transformers Power transformer insulation Circuit faults Moisture measurement Plasma temperature Application software Humidity

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Enhanced electrification charge densities due to recirculatory flow

Enhanced electrification charge densities due to recirculato...

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International Conference on Properties and Applications of Properties and Applications of Dielectric Materials

作者： A.P. Washabaugh M. Zahn J.R. Melcher Dept. of Electr. Eng. & Comput. Sci. MIT Cambridge MA USA Department of Electrical Engineering and Computer Science Laboratory for Electromagnetic and Electronic Systems Massachusetts Institute of Technology Cambridge MA USA

A model is developed for volume charge accumulation in recirculatory flow between a charge source and several charge relaxation regions. According to the model, large volume charge densities result if the residence time in the relaxation volumes is small compared to the oil dielectric relaxation time. Under these conditions, charge can accumulate in the oil with each pass through the flow loop, until charge leakage just balances charge generation. To stimulate the volume charge accumulation in a transformer, a flow loop experiment was developed in which transformer oil was circulated at volume flow rates of 2-20 GPM between a 55-gallon reservoir and a paper cellulose filter. The charge density entering and exiting the filter was simultaneously measured using absolute charge sensors. Bypassing the reservoir resulted in increased volume charge densities, in agreement with the model. It is concluded that charge densities can be enhanced by recirculated flow if the charge is not allowed to significantly relax before re-entering a paper filter charge source.< >

关键词： Volume relaxation Filters Petroleum Oil insulation Lubricating oils Dielectrics Hydrocarbon reservoirs Density measurement Current measurement Charge measurement

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An optimal control problem arising in flexible manufacturing systems

An optimal control problem arising in flexible manufacturing...

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IEEE Conference on Decision and Control

作者： M.K. Ghosh A. Arapostathis S.I. Marcus Department of Electrical and Computer Engineering University of Texas Austin Austin TX USA Dept. of Electr. & Comput. Eng. Texas Univ. Austin TX USA Systems Research Center University of Maryland College Park MD USA

A controlled switching diffusion model is developed to study the hierarchical control of flexible manufacturing systems. The existence of a homogeneous Markov nonrandomized optimal policy is established by a convex analytic method. Using the existence of such a policy, the existence of a unique solution in a certain class to the associated Hamilton-Jacobi-Bellman equations is established, and the optimal policy is characterized as a minimizing selector of an appropriate Hamiltonian.< >

关键词： Optimal control Flexible manufacturing systems Control systems Workstations Assembly Production Buffer storage computer aided manufacturing Process control Diffusion processes

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Operation of microfabricated harmonic and ordinary side-drive motors

Operation of microfabricated harmonic and ordinary side-driv...

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IEEE International Conference on Micro Electro Mechanical systems

作者： M. Megregany P. Nagarkar S.D. Senturia J.H. Lang Dept. of Electr. Eng. & Comput. Sci. MIT Cambridge MA USA Microsystems Technology Laboratories Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA Laboratory for Electromagnetic and Electronic Systems Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA

A variable-capacitance harmonic side-drive motor is presented and the operation of this motor and ordinary variable-capacitance side-drive motors without the need for air-levitation assist is reported. Native oxide formation on motor polysilicon surfaces, resulting from the clamping of the rotor to the shield beneath it, is identified as the cause of motor operational failure. With proper release and testing directed at minimizing this oxide formation, the motors can be readily operated. Operational characteristics of the micromotors, including the role of rotor electric shielding, speed, and frictional effects, are studied. For the side-drive motors, measurements of stopping and starting voltages indicate that the drive torque required to sustain motor operation is 5-7 pN-m, while that required to initiate motor operation after a 30 second rest is nearly twice as high.< >

关键词： Micromotors Rotors Contacts Clamps Stators Laboratories Testing Electrostatic levitation Torque measurement Voltage

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TiSi 2 Thin Films Formed on Crystalline and Amorphous Silicon

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MRS Online Proceedings Library 1990年第1期181卷 167-172页

作者： Z.G. Xiao H. Jiang J. Honeycutt C.M. Osburn G. McGuire G.A. Rozgonyi Dept. of Materials Science and Engineering North Carolina State University Raleigh USA The Royal Institute of Technology Solid State Electronics Kista Sweden Dept.of Electrical and Computer Engineering North Carolina State University Raleigh USA Microelectronics Center of North Carolina Research Triangle Park USA

TiSi2 thin films were formed on crystalline and amorphous silicon substrates obtained by Ge+ and Ge++B+ implantation and optional subsequent annealing. Transmission electron microscopy, X-ray diffraction and electrical resistivity analysis revealed that the silicide formed on amorphous Si has more tendency to have a C54 structure rather than the metastable C49 structure. Also, the grain size is smaller and the silicide/silicon interface is smoother for silicides formed on amorphous Si. Comparison between implanted and unimplanted, (100) and (111) Si substrates indicated that the origin of the differences can be attributed to the latent energy stored in amorphous silicon, which favors the silicide with fine grains and promotes the transformation to the C54 phase. Non-random distribution of planar defects in C49 grains has been observed by plan-view TEM. A proposal that these defects are transformation stress induced microtwins is presented.

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A study of ultra shallow junctions by diffusion from self-aligned silicides 19

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19th European Solid State Device Research Conference, ESSDERC 1989

作者： Jiang, H. Osburn, C.M. Xiao, Z.-G. Smith, P. McGuire, G. Rozgonyi, G.A. Dept. of Electrical and Computer Engineering North Carolina State University RaleighNC United States Royal Institute of Technology Electrum Solid State Electronics Kista Sweden Microelectronics Center of North Carolina Box 12889 Research Triangle ParkNC United States Dept. of Materials Science North Carolina State University RaleighNC United States

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Kerr electro-optic field mapping measurements in liquid nitrogen

Kerr electro-optic field mapping measurements in liquid nitr...

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Conference on electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： A. Kanematsu M. Zahn Dept. of Electr. Eng. & Comput. Sci. MIT Cambridge MA USA Department of Electrical Engineering and Computer Science Laboratory for Electromagnetic and Electronic Systems High Voltage Research Laboratory Massachusetts Institute of Technology Cambridge MA USA

Kerr electrooptic field mapping measurements were made in liquid nitrogen at 70 psi and -177 degrees C. A sensitive measurement technique was used whereby a small-signal AC voltage was superimposed on a DC level. The nonlinear optical effect then gave an optical signal with a DC level and AC harmonic at the same frequency as the AC voltage. The amplitude of the AC optical signal was proportional to the local electric field and was measured with a lock-in amplifier. For 6330-nm-wavelength light the Kerr constant was measured to be B approximately=10/sup -16/ m/V/sup 2/. Steady-state electric fields between parallel stainless steel electrodes of gap 7 mm and area 31.6 cm/sup 2/ were shown to be essentially uniform for field strengths up to 90 kV/cm with no significant space charge distortion. The DC voltage-current characteristic was also measured and found to be nonohmic, reaching constant current of approximately=13 nA over the voltage range of approximately=30-60 kV.< >

关键词： Nitrogen Voltage Nonlinear optics Stimulated emission Optical distortion Optical sensors Electric fields Pressure measurement Measurement techniques Frequency

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