作者：
Griffin, Daniel W.Lim, Jae S.MIT
Dep of Electrical Engineering & Computer Science Cambridge MA USA MIT Dep of Electrical Engineering & Computer Science Cambridge MA USA
A new model-based speech analysis/synthesis system is presented. In this method, the short-time spectrum of speech is modeled as the product of an excitation spectrum and a spectral envelope. The spectral envelope is ...
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A new model-based speech analysis/synthesis system is presented. In this method, the short-time spectrum of speech is modeled as the product of an excitation spectrum and a spectral envelope. The spectral envelope is some smoothed version of the speech spectrum, and the excitation spectrum is represented by the pitch period and a voiced/unvoiced (V/UV) decision for each harmonic. In speech analysis, the model parameters are estimated by explicit comparison between the original speech spectrum and the synthetic speech spectrum. Preliminary results indicate that speech and noisy speech synthesized on the basis of this model do not have the 'buzziness' typically associated with vocoder speech and are essentially the same as the original speech or the noisy speech in both intelligibility and quality. Potential applications of this new model and its parameter estimation include high-quality speech analysis/synthesis, time-scale modification of speech and noisy speech, and pitch detection.
作者：
Sussman, Gerald JayMIT
Dep of Electrical Engineering & Computer Science Cambridge MA USA MIT Dep of Electrical Engineering & Computer Science Cambridge MA USA
Software engineering needs appropriate tools to support each of the phases of the engineering process. There must be tools to aid with specification and modelling, with synthesis and analysis, with rapid-prototyping a...
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ISBN:
(纸本)0818606207
Software engineering needs appropriate tools to support each of the phases of the engineering process. There must be tools to aid with specification and modelling, with synthesis and analysis, with rapid-prototyping and debugging, with documentation, verification, and testing, and with maintenance of finished products. In addition there must be environmental tools to support the engineering process in the large. Artificial intelligence research often uses programs as theoretical constructs, akin to equations and schematic diagrams, but with the added feature that programs that embody parts of a theory of the design of programs can be used as tools in the process of theory construction (or software development). Most AI experiments are formulated in Lisp. Lisp has developed into a uniquely powerful and flexible family of software development tools, providing wrap-around support for the rapid-prototyping of software systems.
作者：
Haus, HermannWhitaker Jr., Norman A.MIT
Dep of Electrical Engineering & Computer Science Cambridge MA USA MIT Dep of Electrical Engineering & Computer Science Cambridge MA USA
Requirements for all-optical logic devices for waveguide optics are stated. Existing proposals for such devices are briefly reviewed. The Mach-Zehnder waveguide structure is discussed. The device opportunities offered...
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ISBN:
(纸本)0892525525
Requirements for all-optical logic devices for waveguide optics are stated. Existing proposals for such devices are briefly reviewed. The Mach-Zehnder waveguide structure is discussed. The device opportunities offered by the Multiple-Quantum-Well structures are discussed.
作者：
Adler, DavidMIT
Dep of Electrical Engineering & Computer Science Cambridge MA USA MIT Dep of Electrical Engineering & Computer Science Cambridge MA USA
The characterization necessary to account for the physical properties and device performance of any semiconducting material is presented. This can be divided into five major categories. The results of intensive studie...
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ISBN:
(纸本)0892525789
The characterization necessary to account for the physical properties and device performance of any semiconducting material is presented. This can be divided into five major categories. The results of intensive studies of hydrogenated amorphous silicon thin films are reviewed in detail. It is concluded that many important characteristics of these commercially important materials are still not known with any degree of certainty.
作者：
MINSKY, MMIT
Dep of Electrical Engineering & Computer Science Cambridge MA USA MIT Dep of Electrical Engineering & Computer Science Cambridge MA USA
Problems facing humans in communicating with other intelligent beings are discussed. The ability to solve new different problems is considered to be a distinctive aspect of intelligence. Two arguments are proposed for...
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Problems facing humans in communicating with other intelligent beings are discussed. The ability to solve new different problems is considered to be a distinctive aspect of intelligence. Two arguments are proposed for why aliens in outer space may think like human beings: economics and sparseness. These arguments are based on the idea that all intelligent problem solvers are subject to the same ultimate constraints-limitations on space, time, and materials. For animals to evolve powerful ways to deal with such constraints, they must have ways to represent the situations they face, and they must have processes for manipulating those representations. A glossary of artificial-intelligence (AI) terms is furnished.
A new type of information system is described that combines personal computers, broadcast data communication, and bidirectional communication. The system is designed to use broadcast communication whenever possible to...
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A new type of information system is described that combines personal computers, broadcast data communication, and bidirectional communication. The system is designed to use broadcast communication whenever possible to deliver information to personal computers, which are used for data storage, indexing, and retrieval. This paper starts with an overview of the system, and then discusses the problem of reliable digital broadcast communication in some detail. A parameterized broadcast protocol is described, and it is shown how to choose protocol parameters based on observed channel error characteristics. A flexible encryption-based protection system is included in the protocol. The implementation of the system on contemporary personal computers is discussed.
作者：
Donahue, T.J.Reif, R.MIT
Dep of Electrical Engineering & Computer Science Cambridge MA USA MIT Dep of Electrical Engineering & Computer Science Cambridge MA USA
A system and a procedure using chemical vapor deposition at very low pressures have been developed for depositing uniform, specular silicon epitaxial films both with and without plasma enhancement at temperature as lo...
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A system and a procedure using chemical vapor deposition at very low pressures have been developed for depositing uniform, specular silicon epitaxial films both with and without plasma enhancement at temperature as low as 650 degree C. This low temperature process for depositing epitaxial silicon will be necessary for future bipolar and CMOS technologies to minimize autodoping and solid-state diffusion effects. Of the processes that have been proposed, such as molecular beam epitaxy, ion beam epitaxy, solid phase epitaxy and plasma enhanced chemical vapor deposition (PECVD), only PECVD appears to be compatible with manufacturing requirements such as high throughput, conformal coverage and low cost.
This paper reports a network implementation for the IBM Personal computer that uses several performance-oriented design techniques with wide applicability: an upcall/downcall organization that simplifies structure;imp...
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This paper reports a network implementation for the IBM Personal computer that uses several performance-oriented design techniques with wide applicability: an upcall/downcall organization that simplifies structure;implementation layers that do not always coincide with protocol specification layers;copy minimization;and tailoring of protocol implementations with knowledge of the application that will use them. The size and scale of the resulting package of programs, now in use in our laboratory for two years, is quite reasonable for a desktop computer and the techniques developed are applicable to a wider range of network protocol designs.
作者：
Quach, N.T.Reif, R.MIT
Dep of Electrical Engineering & Computer Science Cambridge MA USA MIT Dep of Electrical Engineering & Computer Science Cambridge MA USA
Thin polycrystalline Si films (230 nm) were deposited on Si substrates by low-pressure chemical vapor deposition and amorphized by self-implantation at minus 150 to minus 170 degree C. After a 5 h N//2 anneal at 550 d...
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Thin polycrystalline Si films (230 nm) were deposited on Si substrates by low-pressure chemical vapor deposition and amorphized by self-implantation at minus 150 to minus 170 degree C. After a 5 h N//2 anneal at 550 degree C, the amorphized films recrystallized into monocrystalline films of reasonable quality as determined by reflection electron diffraction and transmission electron microscopy. A concentrated hf rinse prior to the polysilicon film deposition was found to be crucial.
Ultrashort pulsed laser techniques are used to study high speed processes in electronic materials and devices. High repetition rate picosecond sources make possible sensitive, time-resolved detection of small changes ...
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Ultrashort pulsed laser techniques are used to study high speed processes in electronic materials and devices. High repetition rate picosecond sources make possible sensitive, time-resolved detection of small changes in optical absorption, reflectivity and anisotropy. These changes indicate changes in carrier density, level of excitation and local electric fields. Different laser systems allow investigation of dynamic events from the picosecond into the femtosecond time scale in a variety of different materials.
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