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Spectral representations of nonmodal phonation

Published in:
IEEE Trans. Audio, Speech, Language Proc., Vol. 16, No. 1, January 2008, pp. 34-46.

Summary

Regions of nonmodal phonation, which exhibit deviations from uniform glottal-pulse periods and amplitudes, occur often in speech and convey information about linguistic content, speaker identity, and vocal health. Some aspects of these deviations are random, including small perturbations, known as jitter and shimmer, as well as more significant aperiodicities. Other aspects are deterministic, including repeating patterns of fluctuations such as diplophonia and triplophonia. These deviations are often the source of misinterpretation of the spectrum. In this paper, we introduce a general signal-processing framework for interpreting the effects of both stochastic and deterministic aspects of nonmodality on the short-time spectrum. As an example, we show that the spectrum is sensitive to even small perturbations in the timing and amplitudes of glottal pulses. In addition, we illustrate important characteristics that can arise in the spectrum, including apparent shifting of the harmonics and the appearance of multiple pitches. For stochastic perturbations, we arrive at a formulation of the power-spectral density as the sum of a low-pass line spectrum and a high-pass noise floor. Our findings are relevant to a number of speech-processing areas including linear-prediction analysis, sinusoidal analysis-synthesis, spectrally derived features, and the analysis of disordered voices.
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Summary

Regions of nonmodal phonation, which exhibit deviations from uniform glottal-pulse periods and amplitudes, occur often in speech and convey information about linguistic content, speaker identity, and vocal health. Some aspects of these deviations are random, including small perturbations, known as jitter and shimmer, as well as more significant aperiodicities. Other...

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Performance metrics and software architecture

Published in:
High Performance Embedded Computing Handbook, Chapter 15

Summary

This chapter presents that high performance embedded computing (HPEC) software architectures and evaluation metrics. A canonical HPEC application is used to illustrate basic concepts. The chapter discusses different types of parallelism are reviewed, and performance analysis techniques. It presents a typical programmable multicomputer and explores the performance trade-offs of different parallel mappings on this computer using key system performance metrics. HPEC systems are amongst the most challenging systems in the world to build. Synthetic Aperture Radar (SAR) is one of the most common modes in a radar system and one of the most computationally stressing to implement. Often the first step in the development of a system is to produce a rough estimate of how many processors will be needed. The parallel opportunities at each stage of the calculation discussed in the previous section show that there are many different ways to exploit parallelism in this application. The chapter concludes with a discussion of the impact of different software implementations approaches.
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Summary

This chapter presents that high performance embedded computing (HPEC) software architectures and evaluation metrics. A canonical HPEC application is used to illustrate basic concepts. The chapter discusses different types of parallelism are reviewed, and performance analysis techniques. It presents a typical programmable multicomputer and explores the performance trade-offs of different...

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Radar Signal Processing: An Example of High Performance Embedded Computing

Published in:
High Performance Embedded Computing Handbook, Chapter 6

Summary

This chapter focuses on the computational complexity of the front-end of the surface moving-target indication (SMTI) radar application. SMTI radars can require over one trillion operations per second of computation for wideband systems. The adaptive beamforming performed in SMTI radars is one of the major computational complexity drivers. The goal of the SMTI radar is to process the received signals to detect targets while rejecting clutter returns and noise. The radar must also mitigate interference from unintentional sources such as RF systems transmitting in the same band and from jammers that may be intentionally trying to mask targets. The pulse compression stage filters the data to concentrate the signal energy of a relatively long transmitted radar pulse into a short pulse response. The relative range rate between the radar and the ground along the line of sight of the sidelobe may be the same as range rate of the target detected in the mainbeam.
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Summary

This chapter focuses on the computational complexity of the front-end of the surface moving-target indication (SMTI) radar application. SMTI radars can require over one trillion operations per second of computation for wideband systems. The adaptive beamforming performed in SMTI radars is one of the major computational complexity drivers. The goal...

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Parallel and Distributed Processing

Author:
Published in:
High Performance Embedded Computing Handbook, Chapter 18

Summary

This chapter discusses parallel and distributed programming technologies for high performance embedded systems. Computational or memory constraints can be overcome with parallel processing. The primary goal of parallel processing is to improve performance by distributing computation across multiple processors or increasing dataset sizes by distributing data across multiple processors’ memory. The typical programmer has little to no experience writing programs that run on multiple processors. The transition from serial to parallel programming requires significant changes in the programmer’s way of thinking. For example, the programmer must worry about how to distribute data and computation across multiple processors to maximize performance and how to synchronize and communicate between processors. Although most programmers will likely admit to having no experience with parallel programming, many have indeed had exposure to a rudimentary type in the form of threads. A typical threaded program starts execution as a single thread.
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Summary

This chapter discusses parallel and distributed programming technologies for high performance embedded systems. Computational or memory constraints can be overcome with parallel processing. The primary goal of parallel processing is to improve performance by distributing computation across multiple processors or increasing dataset sizes by distributing data across multiple processors’ memory...

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All silicon infrared photodiodes: photo response and effects of processing temperature

Summary

CMOS compatible infrared waveguide Si photodiodes are made responsive from 1100 to 1750 nm by Si+ implantation and annealing. This article compares diodes fabricated using two annealing temperatures, 300 and 475C. 0.25-mm-long diodes annealed to 300C have a response to 1539 nm radiation of 0.1 A W-1 at a reverse bias of 5 V and 1.2 A W-1 at 20 V. 3-mm-long diodes processed to 475C exhibited two states, L1 and L2, with photo responses of 0.3 +/-0.1 A W-1 at 5 V and 0.7 +/-10.2 A W-1 at 20 V for the L1 state and 0.5 +/-0.2 A W-1 at 5 V and 4 to 20 A W-1 at 20 V for the L2 state. The diodes can be switched between L1 and L2. The bandwidths vary from 10 to 20 GHz. These diodes will generate electrical power from the incident radiation with efficiencies from 4 to 10 %.
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Summary

CMOS compatible infrared waveguide Si photodiodes are made responsive from 1100 to 1750 nm by Si+ implantation and annealing. This article compares diodes fabricated using two annealing temperatures, 300 and 475C. 0.25-mm-long diodes annealed to 300C have a response to 1539 nm radiation of 0.1 A W-1 at a reverse...

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Topic identification from audio recordings using word and phone recognition lattices

Published in:
2000 IEEE Workshop on Automatic Speech Recognition and Understanding, 9-13 December 2007, pp. 659-664.

Summary

In this paper, we investigate the problem of topic identification from audio documents using features extracted from speech recognition lattices. We are particularly interested in the difficult case where the training material is minimally annotated with only topic labels. Under this scenario, the lexical knowledge that is useful for topic identification may not be available, and automatic methods for extracting linguistic knowledge useful for distinguishing between topics must be relied upon. Towards this goal we investigate the problem of topic identification on conversational telephone speech from the Fisher corpus under a variety of increasingly difficult constraints. We contrast the performance of systems that have knowledge of the lexical units present in the audio data, against systems that rely entirely on phonetic processing.
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Summary

In this paper, we investigate the problem of topic identification from audio documents using features extracted from speech recognition lattices. We are particularly interested in the difficult case where the training material is minimally annotated with only topic labels. Under this scenario, the lexical knowledge that is useful for topic...

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Irreversible electrowetting on thin fluoropolymer films

Published in:
Langmuir, Vol. 23, No. 24, 20 November 2007, pp. 12429-12435.

Summary

A study was conducted to investigate electrowetting reversibility associated with repeated voltage actuations for an aqueous droplet situated on a silicon dioxide insulator coated with an amorphous fluoropolymer film ranging in thickness from 20 to 80 nm. The experimental results indicate that irreversible trapped charge may occur at the aqueous-solid interface, giving rise to contact angle relaxation. The accumulation of trapped charge was found to be related to the applied electric field intensity and the breakdown strength of the fluoropolymer. On the basis of the data, an empirical model was developed to estimate the amount of trapped charge in the fluoropolymer as well as the voltage threshold for the onset of irreversible electrowetting.
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Summary

A study was conducted to investigate electrowetting reversibility associated with repeated voltage actuations for an aqueous droplet situated on a silicon dioxide insulator coated with an amorphous fluoropolymer film ranging in thickness from 20 to 80 nm. The experimental results indicate that irreversible trapped charge may occur at the aqueous-solid...

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A low-loss double-tuned transformer

Published in:
IEEE Microw. Wirel. Compon. Lett., Vol. 17, No. 11, November 2007, pp. 772-774.

Summary

In this letter, we present a state-of-the-art, planar double-tuned transformer using high- , micromachined spiral inductors and integrated capacitors. This circuit provides a 4:1 impedance transformation over a 30% bandwidth centered at 4.06 GHz, with a minimum insertion loss of 1.50 dB. The fabricated circuit occupies a total area of 440 500 m2 and finds application in power amplifier and other matching applications. An accurate lumped-element circuit model and design tradeoffs are presented. We believe this is the first implementation of a planar microwave double-tuned transformer.
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Summary

In this letter, we present a state-of-the-art, planar double-tuned transformer using high- , micromachined spiral inductors and integrated capacitors. This circuit provides a 4:1 impedance transformation over a 30% bandwidth centered at 4.06 GHz, with a minimum insertion loss of 1.50 dB. The fabricated circuit occupies a total area of...

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Advanced trigger development

Published in:
Lincoln Laboratory Journal, Vol. 17, No. 1, November 2007, pp. 29-62.

Summary

The deadliest form of a biological attack is aerosolized agents dispersed into the atmosphere. Early detection of aerosolized biological agents is important for defense against these agents. Because of the wide range of possible attack scenarios and attack responses, there is also a wide range of detector requirements. This article focuses on real-time, single-particle, optically based bio-agent trigger detectors--the first responder to an aerosol attack--and how to engineer these detectors to achieve optimal detection performance.
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Summary

The deadliest form of a biological attack is aerosolized agents dispersed into the atmosphere. Early detection of aerosolized biological agents is important for defense against these agents. Because of the wide range of possible attack scenarios and attack responses, there is also a wide range of detector requirements. This article...

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The next-generation multimission U.S. surveillance radar network

Published in:
Bull. American Meteorological Society, Vol. 88, No. 11, November 2007, pp. 1739-1751.

Summary

Current U.S. weather and aircraft surveillance radar networks vary in age from 10 to more than 40 years. Ongoing sustainment and upgrade programs can keep these operating in the near to mid-term, but the responsible agencies National Weather Service (NWS), Federal Aviation Administration (FAA), and the Departments of Defense (DoD) and Homeland Security (DHS) recognize that large-scale replacement activities must begin during the next decade. The National Weather Radar Testbed (NWRT) in Norman, Oklahoma, is a multiagency project demonstrating operational weather measurements capability enhancements that could be realized using electronically steered phased-array radars as a replacement for the current Weather Surveillance Radar-1988 Doppler (WSR-88D). FAA support for the NWRT and related efforts address air traffic control (ATC) and homeland defense surveillance missions that could be simultaneously accomplished using the agile-beam capability of a phased array weather radar network. In this paper, we discuss technology issues, operational considerations, and cost trades associated with the concept of replacing current national surveillance radars with a single network of multimission phased array radars (MPAR). We begin by describing the current U.S. national weather and aircraft surveillance radar networks and their technical parameters. The airspace coverage and surveillance capabilities of these existing radars provide a starting point for defining requirements for the next-generation airspace surveillance system. We next describe a conceptual MPAR high-level system design and our initial development and testing of critical subsystems. This work, in turn, has provided a solid basis for estimating MPAR costs for comparison with existing, mechanically scanned operational surveillance radars. To assess the numbers of MPARs that would need to be procured, we present a conceptual MPAR network configuration that duplicates airspace coverage provided by current operational radars. Finally, we discuss how the improved surveillance capabilities of MPAR could be utilized to more effectively meet the weather and aircraft surveillance needs of U.S. civil and military agencies.
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Summary

Current U.S. weather and aircraft surveillance radar networks vary in age from 10 to more than 40 years. Ongoing sustainment and upgrade programs can keep these operating in the near to mid-term, but the responsible agencies National Weather Service (NWS), Federal Aviation Administration (FAA), and the Departments of Defense (DoD)...

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