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Conference on Health Monitoring of Structural and Biological Systems

作者： Oliver, J. A. Kosmatka, J. B. Farrar, Charles R. Park, Gyuhae Univ Calif San Diego Dept Struct Engn 9500 Gilman Dr La Jolla CA 92903 USA Los Alamos Natl Lab Engn Inst Los Alamos NM 87545 USA

ISBN: (纸本)9780819466532

In order to facilitate damage detection and structural health monitoring (SHM) research for composite unmanned aerial vehicles (UAV) a specialized test-bed has been developed. This test-bed consists of four 2.61 m all-composite test-pieces emulating composite UAV wings, a series of detailed finite element models of the test-pieces and their components, and a dynamic testing setup including a mount for simulating the cantilevered operation configuration of real wings. Two of the wings will have bondline damage built in;one undamaged and one damaged wing will also be fitted with a range of embedded and attached sensors-piezoelectric patches, fiber-optics, and accelerometers. These sensors will allow collection of realistic data;combined with further modal testing they will allow comparison of the physical impact of the sensors on the structure compared to the damage-induced variation, evaluation of the sensors for implementation in an operational structure, and damage detection algorithm validation. At the present time the pieces for four wings have been fabricated and modally tested and one wing has been fully assembled and re-tested in a cantilever configuration. The component part and assembled wing finite element models, created for ***, have been correlated to their respective structures using the modal information. This paper details the design and manufacturing of the test-pieces, the finite element model construction, and the dynamic testing setup. Measured natural frequencies and mode shapes for the assembled cantilevered wing are reported, along with finite element model undamaged modal response, and response with a small disbond at the root of the top main spar-skin bondline.

关键词： Sensors Unmanned aerial vehicles Skin Structural health monitoring Composites Data modeling Finite element methods Assembly equipment algorithm development Damage detection

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Recent advances in the development of a novel aerosol sorting and deposition system for bio-threat sensing applications

Recent advances in the development of a novel aerosol sortin...

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Conference on Electro-Optical Remote Sensing, Detection, and Photonic Technologies and Their Applications

作者： Pletcher, Timothy McGinn, Joseph Keller, David Huston, Alan Eversole, Jay Sivaprakasum, Vasanthi Sarnoff Corp 201 Washington Rd Princeton NJ 08540 USA Naval Res Lab Washington DC 20375 USA

ISBN: (纸本)9780819468970

Sarnoff Corporation and the Naval Research Laboratory, through support of the U.S. Department of Homeland Security, are developing an automated, high throughput bio-aerosol physical enrichment system designed for use as part of a biological-threat protection system. The Biological Aerosol-Capture-Enrichment (BioACE) system is a bio-aerosol collection system that combines three unique technologies to create physically enriched aerosol samples that can be subsequently interrogated by any number of bio-threat detection systems for the presence of threat agents. An air-to-air concentrator uses an inertial separation technique to highly concentrate an aerosol sample presented to a dual wavelength ultra-violet laser induced fluorescence (UVLIF) optical trigger used to discriminate potential threat particles from non-threat particles conveyed in a collimated particle stream. This particle classification information is used to trigger an electrostatic deposition mechanism to deposit only those particles determined to be potential bio-threats onto a stainless steel substrate. Non-threat particles are discarded with the exiting airflow. The goal for the most recent development effort has been the integration and optimization of these technologies into a unit capable of producing highly enriched particulate samples from ambient air containing variable background aerosol loading and type. Several key technical and engineering challenges were overcome during the course of this development including a unique solution for compensating particle velocity dispersion within the airflow, development of a real-time signal acquisition and detection algorithm for determining material type on a particle by particle basis at rates greater than 2000 particles per second, and the introduction of a robust method for transferring deposited particulate into a 50ul wet sample suitable for most advanced bio-detection techniques. This paper will briefly describe the overall system architecture and

关键词： Particles Atmospheric particles algorithm development Aerosols Signal processing Ultraviolet radiation Near infrared Solar concentrators Crystals Luminescence

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Cognitive engineering in algorithm development for multisensor data fusion in military applications

Cognitive engineering in algorithm development for multisens...

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Conference on Multisensor, Multisource Information Fusion

作者： Kight, AC Narayanan, S Wright State Univ Dept Biomed Ind & Human Factors Engn Dayton OH 45435 USA

ISBN: (纸本)0819453579

In battlefield situations, human operators are bombarded with substantial amounts of information and expected to make near-instantaneous decisions. The large amounts of information, coupled with short decision times and the need to reduce the potential of making incorrect decisions, create the possibility for information overload. This problem is especially prominent in military applications involving imagery from multiple sensors. Computer-based algorithms for fusing pertinent sets of imagery have proven somewhat useful for alleviating this problem. However, little research has been done on designing multisensor data fusion systems using principles of cognitive engineering, which involves the consideration of human cognition during the design process. The design of a sensor fusion system using principles from cognitive engineering would create a more natural relationship between human and machine, and would thus be extremely effective in reducing operator error in military situations. This paper explores the need for integrating human reasoning and cognition in algorithm development for multisensor fusion applications.

关键词： algorithm development Data fusion Defense technologies Cognition Image fusion Error analysis Image sensors Sensor fusion Sensors

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White light modeling, algorithm development, and validation on the micro-arcsecond metrology testbed

White light modeling, algorithm development, and validation ...

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Conference on New Frontiers in Stellar Interferometry

作者： Milman, MH Regher, M Shen, TP CALTECH Jet Prop Lab Pasadena CA 91109 USA

ISBN: (纸本)0819454230

The Space Interferometry Mission (SIM), scheduled for launch in early 2010, is an optical interferometer that will perform narrow angle and global wide angle astrometry with unprecedented accuracy, providing differential position accuracies of 1uas, and 4uas global accuracies in position, proper motion and parallax. SIM astrometric measurements are synthesized from pathlength delay measurements provided by three Michelson-type, white light interferometers. Two of the interferometers are used for making precise measurements of variations in the spacecraft attitude, while the third interferometer performs the science measurement. The ultimate performance of SIM relies on a combination of precise fringe measurements of the interfered starlight with picometer class relative distance measurements made between a set of fiducials that define the interferometer baseline vectors. The focus of the present paper is on the development and analysis of algorithms for accurate white light estimation, and on the preliminary validation of these algorithms on the MicroArcsecond Testbed.

关键词： Interferometers Error analysis Metrology algorithm development Signal to noise ratio Interferometry Modulators Visibility Phase measurement Sensors

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Stereo matching via selective multiple windows

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JOURNAL OF ELECTRONIC IMAGING 2007年第1期16卷 013012.1-013012.1页

作者： Adhyapak, Satyajit Anil Kehtarnavaz, Nasser Nadin, Mihai Univ Texas Dept Elect Engn Richardson TX 75080 USA

Window-based correlation algorithms are widely used for stereo matching due to their computational efficiency as compared to global algorithms. In this paper, a multiple window correlation algorithm for stereo matching is presented which addresses the problems associated with a fixed window size. The developed algorithm differs from the previous multiple window algorithms by introducing a reliability test to select the most reliable window among multiple windows of increasing sizes. This ensures that at least one window is large enough to cover a region of adequate intensity variations while at the same time small enough to cover a constant depth region. A recursive computation procedure is also used to allow a computationally efficient implementation of the algorithm. The outcome obtained from a standard set of images with known disparity maps shows that the generated disparity maps are more accurate as compared to two popular stereo matching local algorithms. (c) 2007 SPIE and IS&T.

关键词： algorithm development Reliability Venus Image processing Cameras Volume rendering Distortion Light sources and illumination Visualization Electrical engineering

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Time-frequency analysis for radar classification of land-mine images

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JOURNAL OF ELECTRONIC IMAGING 2007年第3期16卷 033014.1-033014.12页

作者： Wong, David C. Nguyen, Lam H. Gaunaurd, Guillermo C. Army Res Lab Adelphi MD 20783 USA

We use time-frequency (t-f) analysis techniques to examine the echo returns present in synthetic aperture radar (SAR) images of land-mine fields. A flying platform illuminates a mine field containing various types of mines and "confusers," with an ultra-wideband radar. A number of familiar time-frequency distributions are used to inspect the various possible mine locations above and below the ground surface. The 2-dimensional plots generated by these distributions offer a larger variety of features and clues that facilitate the discrimination of each mine type from the others and from possible "confusers." Conclusions emerge that confirm that the pseudo-Wigner-Ville and the Choi-Williams distributions provide the best discrimination results, as was pointed out in earlier work. Larger mines such as the ones denoted here as "type 1" are the easiest to discriminate. Comparison of mines to clutter objects ("confusers') shows that such objects are clearly distinguishable from all the present metal mines. (c) 2007 SPIE and IS&T.

关键词： Mining Synthetic aperture radar Time-frequency analysis Radar Image classification Soil science algorithm development Inspection Metals Spatial resolution

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An improved algorithm for the detection of plumes caused by natural or technological hazards using AVHRR imagery

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REMOTE SENSING OF ENVIRONMENT 2007年第4期108卷 393-406页

作者： Chrysoulakis, N. Herlin, I. Prastacos, P. Yahia, H. Grazzini, J. Cartalis, C. Fdn Res & Technol Hellas Inst Appl & Computat Math Vassilika VoutonPOB 1358 Iraklion 71110 Crete Greece INRIA Rocquencourt Inst Natl Rech Informat & Automat F-78153 Le Chesnay France European Commiss DG Joint Res Ctr Inst Environm & Sustainabil Spatial Data Infrastruct Unit I-21020 Ispra VA Italy Univ Athens Dept Phys GR-15784 Athens Greece

Fires caused by natural or technological disasters emit large amounts of smoke which, once formed into plumes, may affect the human health and the environment. Satellite remote sensing data provide an effective tool to achieve detection and monitoring of these plumes over large areas on a routine basis. Discrimination of plumes on satellite images is a prerequisite to study and retrieve physical, chemical and optical properties of emitted smoke. An improved algorithm for the detection of plumes caused by natural or technological hazards using AVHRR imagery is presented in this study. The method is based on a multi-temporal and multi-spectral change detection algorithm. It is performed in two main steps: a) appropriate spectral and spatial filters are applied on the images acquired before and after a fire event in visible and near-infrared ranges in order to extract the core of the plume;b) a criterion on spectral information is defined as an homogeneity measure that enables, through a modified version of the region-growing method, the spatial expansion of the detected core to include the complete area covered by the plume. Through this approach, a pixel is identified as a plume pixel if it is "close" to the core plume pixels in both spatial and spectral spaces. The algorithm was developed and calibrated using AVHRR images acquired over Spain before and during a major forest fire event on July 16, 2005. It was applied using past events of natural and technological hazards in several locations to ensure its global applicability and robustness. The algorithm produced accurate results in all cases of plumes, either in natural or in technological fire events. Three application cases are presented in this study: A major fire in an industrial installation in London (December 11, 2005), a major fire in Baghdad during the recent war in Iraq (April 1, 2003) and a forest fire in California (September 29, 2005). (c) 2006 Elsevier Inc. All rights reserved.

关键词： plume detection and monitoring algorithm development natural hazards technological accidents changed detection region growing

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Flash on disk for low-power multimedia computing

Flash on disk for low-power multimedia computing

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14th Conference on Multimedia Computing and Networking 2007

作者： Singleton, Leo Nathuji, Ripal Schwan, Karsten Georgia Inst Technol Coll Comp Atlanta GA 30332 USA

ISBN: (纸本)9780819466174

Mobile multimedia computers require large amounts of data storage, yet must consume low power in order to prolong battery life. Solid-state storage offers low power consumption, but its capacity is an order of magnitude smaller than the hard disks needed for high-resolution photos and digital video. In order to create a device with the space of a hard drive, yet the low power consumption of solid-state storage, hardware manufacturers have proposed using flash memory as a write buffer on mobile systems. This paper evaluates the power savings of such an approach and also considers other possible flash allocation algorithms, using both hardware- and software-level flash management. Its contributions also include a set of typical multimedia-rich workloads for mobile systems and power models based upon current disk and flash technology. Based on these workloads, we demonstrate an average power savings of 267 mW (53% of disk power) using hardware-only approaches. Next, we propose another algorithm. termed Energy-efficient Virtual Storage using Application-Level Framing (EVS-ALF), which uses both hardware and software for power management. By collecting information from the applications and using this metadata to perform intelligent flash allocation and prefetching, EVS-ALF achieves an average power savings of 307 mW (61%), another 8% improvement over hardware-only techniques.

关键词： Multimedia Operating systems Video algorithm development Computing systems Systems modeling Solid state electronics Digital photography Data storage Manufacturing

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High-speed parameter estimation algorithms for nonlinear smart materials

High-speed parameter estimation algorithms for nonlinear sma...

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Conference on Modeling, Signal Processing, and Control for Smart Structures 2007

作者： Ernstberger, Jon M. Smith, Ralph C. North Carolina State Univ Dept Math Ctr Res Sci Computat Box 8205 Raleigh NC 27695 USA

ISBN: (纸本)9780819466440

A fundamental step in the model construction for ferroelectric, ferromagnetic, and ferroelastic materials is the estimation or identification of material parameters given measurements of the material response. Moreover, actuator and/or material properties may be a function of operating conditions which can necessitate the re-estimation of parameters if conditions change significantly. In this paper, we focus on the development of highly robust and efficient identification algorithms for use in industrial, aeronautic and aerospace applications. Following a discussion of present and future applications, we summarize the homogenized energy model used to characterize hysteresis and constitutive nonlinearities in these compounds. We next discuss the parameter estimation problem and detail algorithms used to speed implementation. The validity of the framework is illustrated through comparison with experimental data.

关键词： Data modeling Actuators Smart materials Genetic algorithms algorithm development algorithms Ferromagnetics Aerospace engineering Magnetism Transducers

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Active contour-based multiresolution transforms for the segmentation of fluorescence microscope images

Active contour-based multiresolution transforms for the segm...

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Conference on Wavelets XII

作者： Srinivasa, Gowri Fickus, Matthew Kovacevic, Jelena Carnegie Mellon Univ Ctr Bioimage Informat Pittsburgh PA 15213 USA Carnegie Mellon Univ Dept Elect & Comp Engn Pittsburgh PA 15213 USA Air Force Inst Technol Dept Math & Stat Wright Patterson AFB OH USA

ISBN: (纸本)9780819468499

In recent years, the focus in biological science has shifted to understanding complex systems at the cellular and molecular levels, a task greatly facilitated by fluorescence microscopy. Segmentation, a fundamental yet difficult problem, is often the first processing step following acquisition. We have previously demonstrated that a stochastic active contour based algorithm together with the concept of topology preservation TPSTACS) successfully segments single cells from multicell images. In this paper we demonstrate that TPSTACS successfully segments images from other imaging modalities such as DIC microscopy, MRI and fMRI. While this method is a viable alternative to hand segmentation, it;is not yet ready to be used for high-throughput applications due to its large run time. Thus, we highlight some of the benefits of combining TPSTACS with the multiresolution approach for the segmentation of fluorescence microscope images. Here we propose a multiscale active contour (MSAC) transformation framework for developing a family of modular algorithms for the segmentation of fluorescence microscope images in particular, and biomedical. images in general. While this framework retains the flexibility and the high quality of the segmentation provided by active contour-based algorithms, it offers a boost in the efficiency as well as a framework to compute new features that further enhance the segmentation.

关键词： Image segmentation Luminescence Microscopes Proteins Image processing algorithms and systems algorithm development Microscopy Magnetic resonance imaging Transform theory Digital image correlation

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