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Application of the Maximum Entropy method to estimating parameter distributions for sonar signal processing

AIP Conference Proceedings 2007年第1期954卷 427-434页

作者： R. L. Culver H. J. Camin J. A. Ballard C. W. Jemmott L. H. Sibul Graduate Program in Acoustics and Applied Research Laboratory The Pennsylvania State University PO Box 30 State College PA 16804

The Maximum Entropy (MaxEnt) method and Bayesian inference have been employed to incorporate environmental knowledge into the signal processor for a sonar detection application. The sonar receiver is a new Estimator‐Correlator structure that requires only that the probability density function (pdf) of the observation conditioned on the signal belongs to the exponential class, a requirement met by application of the MaxEnt method. Random but statistically correct realizations of the environment are constructed from the pdfs, and an acoustic propagation code is used to propagate acoustic energy through each realization of the environment in a Monte Carlo simulation. From the ensemble of received signals, statistical moments of the signal parameters are estimated and the MaxEnt method is again used to construct signal parameter pdfs. Using Bayesian inference, the predicted parameter pdfs are incorporated into the detection algorithm as a priori information. To evaluate the fidelity of the approach, the statistics of acoustic measurements made during a 1996 experiment in the Strait of Gibraltar are compared with MaxEnt pdfs and simulation predictions.

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Rectangular cymbal arrays for ultrasonic transdermal insulin delivery

Rectangular cymbal arrays for ultrasonic transdermal insulin...

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2007 IEEE Ultrasonics Symposium, IUS

作者： Luis, Joseph Park, Eun-Joo Meyer Jr., Richard J. Smith, Nadine Barrie Graduate Program in Acoustics Pennsylvania State University University Park PA 16802 United States Department of Bioengineering Pennsylvania State University University Park PA 16802 United States Applied Research Laboratory Pennsylvania State University University Park PA 16802 United States

ISBN: (纸本)1424413834

Studies have shown that ultrasound mediated transdermal drug delivery offers a promising potential for needle-less insulin delivery for diabetes treatment. Arrays of cymbal transducers have been shown to be effective in delivering therapeutic levels of insulin to decrease hyperglycemic glucose levels in rats, rabbits and pigs. To improve delivery efficiency of the cymbal arrays, an increase in the spatial intensity field without increasing the size the device or Isptp was desired. A 3 × 1 rectangular cymbal array was designed for this purpose. Rectangular cymbals maximized packing density and allowed the flexural cap resonance and the ceramic length mode resonance frequencies to be designed closer in frequency. Bringing the cap and ceramic resonances closer together increased the transmitting power and improved the electrical efficiency. By using higher order modes excited in the cap while operating at the first ceramic resonance frequency, the intensity spatial area was increased compared to the circular array. With a similar intensity (I sptp ≈ 50 mW/cm2), our goal was to determine if the 3 × 1 rectangular cymbal array could perform significantly better than the 3 × 3 circular array for blood glucose reduction in hyperglycemic rabbits. Nine New Zealand White rabbit (≈ 4.0 kg) experiments were performed in three groups: control (n = 3) and ultrasound exposure with the 3 × 3 circular cymbal array (n = 3) or 3 × 1 rectangular cymbal array (n = 3). The rabbits were anesthetized and their thigh area was shaved for the exposure. A water tight reservoir which held the insulin was fastened between the rabbit's thigh and the ultrasound arrays. At the beginning of the experiment and every 15 minutes for 90 minutes, 0.3 ml of blood was collected from the ear vein to determine the glucose level (mg/dl) using a glucose monitoring system. For comparison between individual rabbits, the change in the blood glucose level was normalized to their initial baseline value. For the cont

关键词： Ultrasonics

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9F-4 Rectangular Cymbal Arrays for Ultrasonic Transdermal Insulin Delivery

9F-4 Rectangular Cymbal Arrays for Ultrasonic Transdermal In...

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IEEE Symposium (IUS) Ultrasonics

作者： J. Luis E.-J. Park R. J. Meyer Jr. N. B. Smith Graduate Program in Acoustics Pennsylvania State University University Park PA USA Department of Bioengineering Pennsylvania State University University Park PA USA Applied Research Laboratory Pennsylvania State University University Park PA USA

Studies have shown that ultrasound mediated transdermal drug delivery offers a promising potential for needle-less insulin delivery for diabetes treatment. Arrays of cymbal transducers have been shown to be effective in delivering therapeutic levels of insulin to decrease hyperglycemic glucose levels in rats, rabbits and pigs. To improve delivery efficiency of the cymbal arrays, an increase in the spatial intensity field without increasing the size the device or Isptp was desired. A 3 times 1 rectangular cymbal array was designed for this purpose. Rectangular cymbals maximized packing density and allowed the flexural cap resonance and the ceramic length mode resonance frequencies to be designed closer in frequency. Bringing the cap and ceramic resonances closer together increased the transmitting power and improved the electrical efficiency. By using higher order modes excited in the cap while operating at the first ceramic resonance frequency, the intensity spatial area was increased compared to the circular array. With a similar intensity (I sptp ap 50 mW/cm ), our goal was to determine if the 3 times 1 rectangular cymbal array could perform significantly better than the 3 times 3 circular array for blood glucose reduction in hyperglycemic rabbits. Nine New Zealand White rabbit (ap 4.0 kg) experiments were performed in three groups: control (n = 3) and ultrasound exposure with the 3 times 3 circular cymbal array (n = 3) or 3 times 1 rectangular cymbal array (n = 3). The rabbits were anesthetized and their thigh area was shaved for the exposure. A water tight reservoir which held the insulin was fastened between the rabbit's thigh and the ultrasound arrays. At the beginning of the experiment and every 15 minutes for 90 minutes, 0.3 ml of blood was collected from the ear vein to determine the glucose level (mg/dl) using a glucose monitoring system. For comparison between individual rabbits, the change in the blood glucose level was normalized to their initial basel

关键词： Insulin Sugar Rabbits Blood Resonance Ultrasonic imaging Ceramics Ultrasonic transducer arrays Drug delivery Resonant frequency

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Eliminating Nonlinear Acoustical Effects From Thermoacoustic Refrigeration Systems

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AIP Conference Proceedings 2006年第1期838卷 407-415页

作者： Steven L. Garrett Robert W. M. Smith Matthew E. Poese Penn State Graduate Program in Acoustics and Applied Research Laboratory State College PA 16804‐0030

Nonlinear acoustical effects dissipate energy that degrades thermoacoustic refrigerator performance. The largest of these effects occur in acoustic resonators and include shock formation; turbulence and boundary layer disruption; and entry/exit (minor) losses induced by changes in resonator cross‐sectional area. Effects such as these also make the creation of accurate performance models more complicated. Suppression of shock formation by intentional introduction of resonator anharmonicity has been common practice for the past two decades. Recent attempts to increase cooling power density by increasing pressure amplitudes has required reduction of turbulence and minor loss by using an new acousto‐mechanical resonator topology. The hybrid resonator still stores potential energy in the compressibility of the gaseous working fluid, but stores kinetic energy in the moving (solid) mass of the motor and piston. This talk will first present nonlinear acoustical loss measurements obtained in a “conventional” double‐Helmholtz resonator geometry (TRITON) that dissipated four kilowatts of acoustic power. We will then describe the performance of the new “bellows bounce” resonator configuration and “vibromechanical multiplier” used in the first successful implementation of this approach that created an ice cream freezer produced at penn state for Ben & Jerry’s.

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Acoustic background noise from sailplane-mounted microphones

Acoustic background noise from sailplane-mounted microphones

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35th International Congress and Exposition on Noise Control Engineering, INTER-NOISE 2006

作者： Gabrielson, Thomas B. Willits, Steven M. Marston, Timothy M. Haering Jr., Edward A. Murray, James E. Stucky, Mark Applied Research Laboratory - Penn State P.O. Box 30 State College PA 16804 United States Graduate Program in Acoustics P.O. Box 30 State College PA 16804 United States Research Aerodynamics NASA Dryden Research Center Edwards CA 93523 United States U.S. Air Force Test Pilot School Edwards AFB 93524 United States

ISBN: (纸本)9781604231366

One of many options for monitoring acoustic events at altitude is a sailplane-mounted sensor. In an attempt to determine the limiting background noise for acoustic measurements from a sailplane, in-flight measurements were made with microphones installed in a Schempp-Hirth Standard Cirrus and a Blanik L23. Recordings were made in steady gliding flight in a stable atmosphere at speeds ranging from 45 to 80 knots. The background noise from a sailplane-mounted microphone shows three distinct regions. The first region, above 100 Hz, is sensor-influenced flow noise and the pressure spectral density is well characterized by a non-dimensional relation. The second region, from several hertz to 100 Hz, is probably the result of sampling pre-existing pressure fluctuations in the atmosphere. For these measurements made in a convectively stable atmosphere, the pressure spectral density was between 0.005 and 0.01 Pa per root hertz (48 to 54 dB with respect to 20 μPa per root hertz). The third region, below 1 Hz, is dominated by pressure fluctuations that correlate strongly with altitude variations - either natural oscillations of the glider or pilot control inputs.

关键词： Spectral density

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Utilization of the k‐space Computational Method to Design an Intracavitary Transrectal Ultrasound Phased Array Applicator for Hyperthermia Treatment of Prostate Cancer

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AIP Conference Proceedings 2006年第1期829卷 435-439页

作者： Osama M. Al‐Bataineh Christopher M. Collins Victor W. Sparrow Robert M. Keolian Nadine Barrie Smith *Department of Bioengineering The Pennsylvania State University University Park PA 16802 ¶Department of Radiology The Pennsylvania State University Hershey PA 17033 †Graduate Program in Acoustics The Pennsylvania State University University Park PA 16802 ‡Applied Research Laboratory The Pennsylvania State University University Park PA 16802

This research utilizes the k‐space computational method to design an intracavitary probe for hyperthermia treatment of prostate cancer. A three‐dimensional (3D) photographical prostate model, utilizing imaging data from the Visible Human Project®, was the basis for inhomogeneous acoustical model development. The acoustical model accounted for sound speed, density, and absorption variations. The k‐space computational method was used to simulate ultrasound wave propagation of the designed phased array through the acoustical model. To insure the uniformity and spread of the pressure in the length of the array, and the steering and focusing capability in the width of the array, the equal‐sized elements of the phased array were 1 × 14 mm. The anatomical measurements of the prostate were used to predict the final phased array specifications (4 × 20 planar array, 1.2 MHz, element size = 1 × 14 mm, array size = 56 × 20 mm). Good agreement between the exposimetry and the k‐space results was achieved. As an example, the −3 dB distances of the focal volume were differing by 9.1% in the propagation direction for k‐space prostate simulation and exposimetry results. Temperature simulations indicated that the rectal wall temperature was elevated less than 2°C during hyperthermia treatment. Steering and focusing ability of the designed probe, in both azimuth and propagation directions, were found to span the entire prostate volume with minimal grating lobes (−10 dB reduction from the main lobe) and least heat damage to the rectal wall. Evaluations of the probe included ex vivo and in vivo controlled experiments to deliver the required thermal dose to the targeted tissue. With a desired temperature plateau of 43.0°C, the MRI temperature results at the steady state were 42.9 ± 0.38°C and 43.1 ± 0.80°C for ex vivo and in vivo experiments, respectively. Unlike conventional computational methods, the k‐space method provides a powerful tool to predict pressure wavefield and temperature r

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Noninvasive Ultrasound Transdermal Insulin Delivery and Glucose Monitoring Using a Low‐Profile Cymbal Array

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AIP Conference Proceedings 2006年第1期829卷 553-557页

作者： E.‐J. Park J. Luis R. J. Meyer M. V. Pishko N. B. Smith *Department of Bioengineering The Pennsylvania State University University Park PA 16802 †Graduate Program in Acoustics The Pennsylvania State University University Park PA 16802 ‡Applied Research Laboratory The Pennsylvania State University University Park PA 16802 §Department of Chemical Engineering The Pennsylvania State University University Park PA 16802

Recent studies have shown that ultrasound mediated transdermal drug delivery offers promising results for noninvasive drug administration. The purpose of this study was to demonstrate ultrasonic transdermal insulin delivery and in vivo sensing glucose with a novel, low‐profile ultrasound array based on the cymbal transducer. As a practical device, the array composed of circular cymbal transducers was thin (< 7mm) and weighed less than 22g. Using this array on hyperglycemic rats, our previous experiments demonstrated that blood glucose would decrease by 296.7 mg/dL from 60 minutes of ultrasound exposure. With a similar intensity, our goal was to evaluate the feasibility of insulin delivery with large animals (rabbits and pigs) and noninvasively determine the glucose level of hyperglycemic rats with the array system. Ultrasound was exposed for 60 minutes at Isptp=100 mW/cm2. With the same procedure, a preliminary experiment of large animal was performed on a pig (12 kg) at Isptp=50 mW/cm2. For the control experiments in insulin delivery, the blood glucose level varied little from the initial baseline. However, for the ultrasound and insulin exposure experiment, the glucose level was found to decrease by 132.6 mg/dL in 60 minutes and continued to decrease by 208.1 mg/dL in 90 minutes. From the preliminary pig experiment, the blood glucose level decreased by 120 mg/dL in 90 minutes. To noninvasively determine the glucose level, ultrasound exposure experiments with an electrochemical glucose biosensor were performed on hyperglycemic rats. After 20 minutes ultrasound exposure, the biosensor was placed at the exposure area to determine the concentration of glucose diffused through the skin. The glucose level of rats determined by the biosensor was 408 mg/dL which was very similar to the results of conventional glucose meter reading 396.7 mg/dL. Recently, a rectangular cymbal transducer was developed to obtain a larger sonication area without an increase in array size. Prel

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Intelligent self-situational awareness for increased autonomy, reduced operational risk, and improved capability

Intelligent self-situational awareness for increased autonom...

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1st Space Exploration Conference: Continuing the Voyage of Discovery

作者： Reichard, Karl M. Banks, Jeff Crow, Eddie C. Weiss, Lora Applied Research Laboratory Pennsylvania State University P.O. Box 30 State College PA 16804 United States Department of Acoustics Penn State United States Maintenance Department University's Applied Research Laboratory United States Department of Systems and Operations Automation Penn State's Applied Research Laboratory United States Applied Research Laboratory Pennsylvania State University United States United States Graduate Faculty in Acoustics United States

ISBN: (纸本)1563477270

Intelligent self-situational awareness refers to the ability of a system to autonomously assess its health and condition and to interpret the impact of its current and future health and condition on current mission objectives. Intelligent self-situational awareness represents a fusion of system health monitoring and intelligent autonomous control and is an extension of embedded diagnostics and prognostics, integrated system health management, and condition based maintenance that incorporates not only the ability to perceive current health and condition, but to assess the impact of the current health and condition within the context of the current mission requirements and resources. Department of Defense investment in system health management has been driven largely by a desire to reduce manning and control operational and sustainment costs associated with maintenance and logistics over the life cycle of systems. Studies conducted by the applied research laboratory have shown payback times of 3-4 years for the investment in system health management for major platforms with significant cost savings and 4-5% improvements in operational availability.1 In order to implement integrated system health management in unmanned systems, the health monitoring capability must be integrated with the autonomous control system to avoid the bandwidth requirements and communication delays associated with sending health and performance-related sensor data back to a human operator. The capability of intelligent self-situational awareness can reduce the cognitive load on humans in manned and collaborative human-robotic missions, reduce the work load for ground support personnel, provides increased ability to respond to unanticipated faults and system degradation, and aid in mission planning and implementation. The benefits associated with the use of traditional embedded diagnostics and prognostics will still apply in space exploration missions: reduced loss of system availability due to

关键词： Space research

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Vibration and rattle impact due to low frequency noise investigated at dulles airport

Vibration and rattle impact due to low frequency noise inves...

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19th National Conference on Noise Control Engineering 2005, Noise-Con 2005

作者： Horan, Erin M. Hodgdon, Kathleen K. Atchley, Anthony A. Graduate Program in Acoustics Pennsylvania State University University Park PA 16802 United States Applied Research Laboratory Pennsylvania State University University Park PA 16802 United States

ISBN: (纸本)9781622762712

The data acquisition conducted at IAD is the very beginning of the LFN study. The recordings made insure that there are an adequate variety of aircraft type and number of events to provide a thorough analysis. Preliminary findings show the difference between the house responses. These differences will be investigated further to better understand the impact upon humans and the effects of house construction on attenuating the impact of the noise events. Though the original rattle design did not produce rattle in either location, the loose window in the stone house, as well as the modified rattle design, provided the opportunity to capture rattle signatures on both the indoor microphone and the HEAD system for a wide selection of events. Further work is planned for a subjective study of annoyance for the rattle signatures that were captured at the stone house. These recordings, as well as signatures without rattle, will be presented to subjects for evaluation. Objective metrics will be calculated for signatures used in the jury evaluation, and these metrics will be correlated with subjective ratings to assess the metric's ability to predict rattle impact. The findings will assist in identifying metrics that best correlate with the human perception of rattle.

关键词： Houses

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Subjective response to low-frequency aircraft noise

Subjective response to low-frequency aircraft noise

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19th National Conference on Noise Control Engineering 2005, Noise-Con 2005

作者： Shapiro, Peter J. Hodgdon, Kathleen K. Atchley, Anthony A. Graduate Program in Acoustics Pennsylvania State University P.O. Box 30 State College PA 16804 United States Applied Research Laboratory Pennsylvania State University P.O. Box 30 State College PA 16804 United States

ISBN: (纸本)9781622762712

The standard metric currently in use by the U.S. government for community noise from aircraft is the Day-Night Level (DNL), which is based on the A-weighting network. However, residents of communities near airports have reported annoyance due to aircraft noise in greater proportion than what the DNL contour associated with their address predicts1. Complaints of "distant rumbling" appear to be related to the low-frequency noise that aircraft produce for which the DNL metric does not fully account 2. This presentation discusses measurements made in October 2004 at two residences near runways at Washington-Dulles International Airport. Noise data are recorded on indoor and outdoor microphones, allowing for a measure of the events' impact both inside and outside the structure, as well as the filtering effect of the structure on the signal. Experimental design for a laboratory subjective study of the recorded aircraft signatures is discussed. Objective metrics, those that are designed for low-frequency noise and those that are not, are to be calculated and correlated with subjective rankings of the signatures. These correlations will gauge the metrics' effectiveness in predicting subjective perception of aircraft noise signatures.

关键词： Aircraft

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