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Sample records for model-based hydroacoustic blockage

  1. MODEL-BASED HYDROACOUSTIC BLOCKAGE ASSESSMENT AND DEVELOPMENT OF AN EXPLOSIVE SOURCE DATABASE

    SciTech Connect

    Matzel, E; Ramirez, A; Harben, P

    2005-07-11

    We are continuing the development of the Hydroacoustic Blockage Assessment Tool (HABAT) which is designed for use by analysts to predict which hydroacoustic monitoring stations can be used in discrimination analysis for any particular event. The research involves two approaches (1) model-based assessment of blockage, and (2) ground-truth data-based assessment of blockage. The tool presents the analyst with a map of the world, and plots raypath blockages from stations to sources. The analyst inputs source locations and blockage criteria, and the tool returns a list of blockage status from all source locations to all hydroacoustic stations. We are currently using the tool in an assessment of blockage criteria for simple direct-path arrivals. Hydroacoustic data, predominantly from earthquake sources, are read in and assessed for blockage at all available stations. Several measures are taken. First, can the event be observed at a station above background noise? Second, can we establish backazimuth from the station to the source. Third, how large is the decibel drop at one station relative to other stations. These observational results are then compared with model estimates to identify the best set of blockage criteria and used to create a set of blockage maps for each station. The model-based estimates are currently limited by the coarse bathymetry of existing databases and by the limitations inherent in the raytrace method. In collaboration with BBN Inc., the Hydroacoustic Coverage Assessment Model (HydroCAM) that generates the blockage files that serve as input to HABAT, is being extended to include high-resolution bathymetry databases in key areas that increase model-based blockage assessment reliability. An important aspect of this capability is to eventually include reflected T-phases where they reliably occur and to identify the associated reflectors. To assess how well any given hydroacoustic discriminant works in separating earthquake and in-water explosion

  2. Hydroacoustic Blockage Calibration for Discrimination

    SciTech Connect

    Harben, P E; Matzel, E; Upton, Z; Pulli, J J

    2003-07-11

    The core focus of this hydroacoustic research is to develop a better understanding of hydroacoustic blockage to better predict those stations that can be used in discrimination analysis for any particular event. The research involves two approaches: (1) model-based assessment of blockage and (2) ground-truth data-based assessment of blockage. The goal is to reliably determine all hydroacoustic stations that can be brought to bear on a discrimination analysis from any event location in the world s oceans. An important aspect of this capability is to include reflected T-phases where they reliably occur since reflected T-phases can allow station utilization when the direct path is otherwise completely blocked. We have conceptually designed an approach to automate assessment procedures that will allow both model-based and data-based methodologies to be utilized and in the future, integrated. We have modified the HydroCAM model-based network assessment code to include variable density bathymetry grids. This will improve the reliability of model-based blockage assessment as dense bathymetry grids are added to the bathymetry database where available and needed. We are also running the HydroCAM code to produce blockage grids in the Indian Ocean for many different blockage criteria. We have been building the database necessary to begin the data driven assessment of blockage. At present, the database is accumulating earthquake events within the Indian Ocean basin as recorded at Diego Garcia and Cape Leeuwin. Over 130 events from 2001 and 2002 have been loaded. Now earthquake event data is automatically loaded into the Lawrence Livermore National Laboratory database at 1-hour record lengths to accommodate future reflection phase analysis. Future work will focus on the utilization of reflected T-phases, the automated use of model-based blockage grids, and the enhancement and use of the data-based method for blockage assessment in the Indian Ocean. The analysis methodology will

  3. Hydroacoustic estimates of fish abundance

    SciTech Connect

    Wilson, W.K.

    1992-06-01

    Mobile hydroacoustic surveys are a recent addition to the sampling techniques available to fisheries biologists. Hydroacoustic techniques for fish stock assessment and monitoring are efficient in providingquantitative biomass estimates, absolute population estimates, fish distribution patterns, and size structure statistics. Other advantages of hydroacoustic surveys include a better method of sampling reservoir pelagic (open water) zones than is available with other techniques, collection of large amounts of data in a relatively short time allowing improved statistical interpretation and data comparisons, and non-destructive, non-invasive sampling that neither destroys the sampled fish nor disturbs the environment. The objective of this study is to use hydroacoustic techniques to estimate fish standing stocks (i.e., numbersand biomass) in several areas of selected Tennessee Valley Reservoirs as part of a base level monitoring program to assess long-term changes in reservoir water quality.

  4. Hydroacoustic estimates of fish abundance

    SciTech Connect

    Wilson, W.K.

    1991-03-01

    Hydroacoustics, as defined in the context of this report, is the use of a scientific sonar system to determine fish densities with respect to numbers and biomass. These two parameters provide a method of monitoring reservoir fish populations and detecting gross changes in the ecosystem. With respect to southeastern reservoirs, hydroacoustic surveys represent a new method of sampling open water areas and the best technology available. The advantages of this technology are large amounts of data can be collected in a relatively short period of time allowing improved statistical interpretation and data comparison, the pelagic (open water) zone can be sampled efficiently regardless of depth, and sampling is nondestructive and noninvasive with neither injury to the fish nor alteration of the environment. Hydroacoustics cannot provide species identification and related information on species composition or length/weight relationships. Also, sampling is limited to a minimum depth of ten feet which precludes the use of this equipment for sampling shallow shoreline areas. The objective of this study is to use hydroacoustic techniques to estimate fish standing stocks (i.e., numbers and biomass) in several areas of selected Tennessee Valley Reservoirs as part of a base level monitoring program to assess long-term changes in reservoir water quality.

  5. A Fusion Model of Seismic and Hydro-Acoustic Propagation for Treaty Monitoring

    NASA Astrophysics Data System (ADS)

    Arora, Nimar; Prior, Mark

    2014-05-01

    We present an extension to NET-VISA (Network Processing Vertically Integrated Seismic Analysis), which is a probabilistic generative model of the propagation of seismic waves and their detection on a global scale, to incorporate hydro-acoustic data from the IMS (International Monitoring System) network. The new model includes the coupling of seismic waves into the ocean's SOFAR channel, as well as the propagation of hydro-acoustic waves from underwater explosions. The generative model is described in terms of multiple possible hypotheses -- seismic-to-hydro-acoustic, under-water explosion, other noise sources such as whales singing or icebergs breaking up -- that could lead to signal detections. We decompose each hypothesis into conditional probability distributions that are carefully analyzed and calibrated. These distributions include ones for detection probabilities, blockage in the SOFAR channel (including diffraction, refraction, and reflection around obstacles), energy attenuation, and other features of the resulting waveforms. We present a study of the various features that are extracted from the hydro-acoustic waveforms, and their correlations with each other as well the source of the energy. Additionally, an inference algorithm is presented that concurrently infers the seismic and under-water events, and associates all arrivals (aka triggers), both from seismic and hydro-acoustic stations, to the appropriate event, and labels the path taken by the wave. Finally, our results demonstrate that this fusion of seismic and hydro-acoustic data leads to very good performance. A majority of the under-water events that IDC (International Data Center) analysts built in 2010 are correctly located, and the arrivals that correspond to seismic-to-hydroacoustic coupling, the T phases, are mostly correctly identified. There is no loss in the accuracy of seismic events, in fact, there is a slight overall improvement.

  6. Blockages to Creativity.

    ERIC Educational Resources Information Center

    Olivier, A.

    The paper examines the nature of creativity and blockages to its expression especially in home and school settings in South Africa. A definition of creativity is offered which stresses the production of an original outcome or achievement. The creative process is broken down into the steps of preparation, incubation, illumination, and verification.…

  7. Can T phases be used to map blockage?

    SciTech Connect

    Harris, D.; Hauk, T.

    1995-05-01

    The placement of stations in a CTBT hydroacoustic monitoring network is controlled, in large part, by the presence of bathymetric features or land masses that block propagation. In the absence of blocking features, propagation is very efficient in the SOFAR channel, allowing surveillance over large basins with hydrophone networks that are sparse compared to seismic networks. Blockage can be estimated from theoretical calculations of acoustic attenuation. While calibration of attenuation with controlled sources is best, it is also prohibitively expensive. The T phases generated by undersea earthquakes are known to be sensitive to interruptions of the SOFAR channel. Earthquakes along ridges may illuminate regions of interest to define blockage areas. Our initial examination of T phase amplitudes suggests that T phases can be used to map blockage or other strong path attenuation. The principal difficulty to be surmounted is the ambiguity between source coupling and path attenuation. We are attempting to quantify coupling with a probabilistic model, which would permit us to estimate attenuation and to quantify the reliability of the estimate.

  8. BBN technical memorandum W1310 hydroacoustic network capability studies

    SciTech Connect

    Angell, J., LLNL

    1997-12-01

    This report summarizes work performed under contract to Lawrence Livermore National Laboratory during the period 1 August to 30 November 1997. Four separate tasks were undertaken during this period which investigated various aspects of hydroacoustic network performance using the Hydroacoustic Coverage Assessment Model (HydroCAM). The purpose of this report is to document each of these tasks.

  9. Optimization of Hydroacoustic Equipment Deployment at Foster Dam, 2013

    SciTech Connect

    Hughes, James S.; Johnson, Gary E.; Ploskey, Gene R.; Hennen, Matthew J.; Fischer, Eric S.; Zimmerman, Shon A.

    2013-03-01

    The goal of the study was to optimize performance of the fixed-location hydroacoustic systems at Foster Dam (FOS) by determining deployment and data acquisition methods that minimized structural, electrical, and acoustic interference. Optimization of the hydroacoustic systems will establish methodology for sampling by active acoustic methods during this year-long evaluation of juvenile salmonid passage at FOS.

  10. Hydroacoustic Estimates of Fish Density Distributions in Cougar Reservoir, 2011

    SciTech Connect

    Ploskey, Gene R.; Zimmerman, Shon A.; Hennen, Matthew J.; Batten, George W.; Mitchell, T. D.

    2012-09-01

    Day and night mobile hydroacoustic surveys were conducted once each month from April through December 2011 to quantify the horizontal and vertical distributions of fish throughout Cougar Reservoir, Lane County, Oregon.

  11. Hydroacoustic Studies Using HydroCAM - Station-centric Integration of Models and Observations Quarterly Report No. 2 January 2003 - March 2003

    SciTech Connect

    Pulli, Jay J.; Upton, Zachary M.

    2003-04-21

    OAK A271 Hydroacoustic Studies Using HydroCAM - Station-centric Integration of Models and Observations Quarterly Report No. 2 January 2003 - March 2003. BBN's work from January through March of 2003 was focused on data collection, data analysis and software development. We continued our efforts to collect ground truth hydroacoustic data from sub-sea earthquakes in the Indian Ocean. These data are recorded on the International Monitoring System stations at Diego Garcia and Cape Leeuwin. The software development effort spanned two areas. Fixing problems and making small improvements to HydroCAM based on meetings at AFTAC in September 2002. We have also begun development of the software that will integrate local high-resolution bathymetry into lower-resolution global bathymetry for acoustic path predictions in HydroCAM. We hope that this will improve HydroCAM's ability to predict acoustic blockage. Unfortunately, due to corporate travel restrictions stemming from the war with Iraq, BBN will not be able to participate in the International Hydroacoustics Meeting in Hobart, Tasmania in May. However, we plan to provide Phil Harben with material to present and we plan to participate in the annual Seismic Research Review in Arizona this September.

  12. Acoustic propagation in rigid ducts with blockage

    NASA Technical Reports Server (NTRS)

    El-Raheb, M.; Wagner, P.

    1982-01-01

    Acoustic levitation has been suggested for moving nonmagnetic material in furnaces for heat processing in space experiments. Basically, acoustic standing waves under resonant conditions are excited in the cavity of the furnace while the material blockage is located at a pressure node and thus at a maximum gradient. The position of the blockage is controlled by displacing the node as a result of frequency change. The present investigation is concerned with the effect of blockage on the longitudinal and transverse resonances of a cylindrical cavity, taking into account the results of a one-dimensional and three-dimensional (3-D) analysis. Based on a Green's function surface element method, 3-D analysis is tested experimentally and proved to be accurate over a wide range of geometric parameters and boundary shapes. The shift in resonance depends on the change in pressure gradient and duct shortening caused by the blockage.

  13. Hydro-acoustic and tsunami waves generated by the 2012 Haida Gwaii earthquake: Modeling and in situ measurements

    NASA Astrophysics Data System (ADS)

    Abdolali, Ali; Cecioni, Claudia; Bellotti, Giorgio; Kirby, James T.

    2015-02-01

    Detection of low-frequency hydro-acoustic waves as precursor components of destructive tsunamis can enhance the promptness and the accuracy of Tsunami Early Warning Systems (TEWS). We reconstruct the hydro-acoustic wave field generated by the 2012 Haida Gwaii tsunamigenic earthquake using a 2-D horizontal numerical model based on the integration over the depth of the compressible fluid wave equation and considering a mild sloped rigid seabed. Spectral analysis of the wave field obtained at different water depths and distances from the source revealed the frequency range of low-frequency elastic oscillations of sea water. The resulting 2-D numerical model gave us the opportunity to study the hydro-acoustic wave propagation in a large-scale domain with available computers and to support the idea of deep-sea observatory and data interpretation. The model provides satisfactory results, compared with in situ measurements, in the reproduction of the long-gravitational waves. Differences between numerical results and field data are probably due to the lack of exact knowledge of sea bottom motion and to the rigid seabed approximation, indicating the need for further study of poro-elastic bottom effects.

  14. Hydroacoustic basis for detection and characterization of eelgrass (Zostera marina)

    SciTech Connect

    Sabol, B.; McCarthy, E.; Rocha, K.

    1997-06-01

    Understanding the distribution and density of seagrasses is important for a variety of environmental applications. Physical techniques for detection and characterization are labor and cost intensive and provide little insight into spatial distribution. optical-based techniques are limited by water clarity - frequently resulting in systematic underestimation of the extent of seagrasses. Active hydroacoustic techniques have shown the ability to detect seagrasses but the phenomenology behind detection is poorly understood. Laboratory and in-situ hydroacoustic measurements are presented for eelgrass (Zostera marina), a common seagrass in the United States. Based on these data, hydroacoustic approaches for wide area detection and mapping are discussed and several are demonstrated within areas of established eelgrass beds in Narragansett Bay, Rhode Island.

  15. Indian Ocean ridge seismicity observed with a permanent hydroacoustic network

    NASA Astrophysics Data System (ADS)

    Hanson, Jeffrey A.; Bowman, J. Roger

    2005-03-01

    The distribution of earthquakes along the Indian Ocean ridge system between January 18 and October 20, 2003 is investigated using data from two hydrophone stations of the International Monitoring System's global network. Coherent array processing of earthquake-induced hydroacoustic T-waves is used to determine precise arrival times and back azimuths that allow automatic location of the earthquakes. We observed 4725 events throughout the Indian Ocean Basin. Here, we examine 1146 earthquakes from the Central and Southeast Indian Ridge. Source level estimates from the hydroacoustic signals indicate that the hydroacoustic network is at least one magnitude unit more sensitive than the seismic network for Indian Ocean ridge earthquakes. The seismicity primarily clusters at ridge transform offsets. Events are observed off the ridge axis near Boomerang and St. Pierre Seamounts, the active expression of the Amsterdam-St. Paul Hotspot. Seismic gaps are observed at several ridge segments with anomalous bathymetric highs.

  16. Hydroacoustic estimates of fish abundance. Reservoir vital signs monitoring, 1990

    SciTech Connect

    Wilson, W.K.

    1991-03-01

    Hydroacoustics, as defined in the context of this report, is the use of a scientific sonar system to determine fish densities with respect to numbers and biomass. These two parameters provide a method of monitoring reservoir fish populations and detecting gross changes in the ecosystem. With respect to southeastern reservoirs, hydroacoustic surveys represent a new method of sampling open water areas and the best technology available. The advantages of this technology are large amounts of data can be collected in a relatively short period of time allowing improved statistical interpretation and data comparison, the pelagic (open water) zone can be sampled efficiently regardless of depth, and sampling is nondestructive and noninvasive with neither injury to the fish nor alteration of the environment. Hydroacoustics cannot provide species identification and related information on species composition or length/weight relationships. Also, sampling is limited to a minimum depth of ten feet which precludes the use of this equipment for sampling shallow shoreline areas. The objective of this study is to use hydroacoustic techniques to estimate fish standing stocks (i.e., numbers and biomass) in several areas of selected Tennessee Valley Reservoirs as part of a base level monitoring program to assess long-term changes in reservoir water quality.

  17. Transcription Blockage Leads to New Beginnings

    PubMed Central

    Andrade-Lima, Leonardo C.; Veloso, Artur; Ljungman, Mats

    2015-01-01

    Environmental agents are constantly challenging cells by damaging DNA, leading to the blockage of transcription elongation. How do cells deal with transcription-blockage and how is transcription restarted after the blocking lesions are removed? Here we review the processes responsible for the removal of transcription-blocking lesions, as well as mechanisms of transcription restart. We also discuss recent data suggesting that blocked RNA polymerases may not resume transcription from the site of the lesion following its removal but, rather, are forced to start over from the beginning of genes. PMID:26197343

  18. The strainer blockage assessment methodology used

    SciTech Connect

    Zigler, G.L.; Rao, D.V.

    1996-03-01

    On July 28, 1992 a spurious opening of a safety valve at Barseback Unit 2 in Sweden resulted in clogging of the Containment Vessel Spray System strainers in less than one hour. Instances of ECCS strainer clogging have occurred in U.S. BWRs. Given these precursors the USNRC staff initiated analyses to estimate the potential for loss of NPSH of the ECCS pumps in BWRs due to clogging of suction strainers by a combination of fibrous and particulate material. The BLOCKAGE code was developed in support of NUREG/CR-6224, a probabilistic scoping analysis of a BWR/4 with a Mark 1 containment. This paper addresses the key elements of the methodology used in the BLOCKAGE code to assess head loss across ECCS strainers. The debris generation model, the debris drywell transport, and the suppression pool models are discussed briefly. NUREG/CR-6224 provides in-depth discussions of the models used in BLOCKAGE. Additionally, user interface features of BLOCKAGE are discussed.

  19. BLOCKAGE 2.5 reference manual

    SciTech Connect

    Shaffer, C.J.; Brideau, J.; Rao, D.V.; Bernahl, W.

    1996-12-01

    The BLOCKAGE 2.5 code was developed by the US Nuclear Regulatory Commission (NRC) as a tool to evaluate license compliance regarding the design of suction strainers for emergency core cooling system (ECCS) pumps in boiling water reactors (BWR) as required by NRC Bulletin 96-03, ``Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors``. Science and Engineering Associates, Inc. (SEA) and Software Edge, Inc. (SE) developed this PC-based code. The instructions to effectively use this code to evaluate the potential of debris to sufficiently block a pump suction strainer such that a pump could lose NPSH margin was documented in a User`s Manual (NRC, NUREG/CR-6370). The Reference Manual contains additional information that supports the use of BLOCKAGE 2.5. It contains descriptions of the analytical models contained in the code, programmer guides illustrating the structure of the code, and summaries of coding verification and model validation exercises that were performed to ensure that the analytical models were correctly coded and applicable to the evaluation of BWR pump suction strainers. The BLOCKAGE code was developed by SEA and programmed in FORTRAN as a code that can be executed from the DOS level on a PC. A graphical users interface (GUI) was then developed by SEA to make BLOCKAGE easier to use and to provide graphical output capability. The GUI was programmed in the C language. The user has the option of executing BLOCKAGE 2.5 with the GUI or from the DOS level and the Users Manual provides instruction for both methods of execution.

  20. Infant Emotional and Cortisol Responses to Goal Blockage

    ERIC Educational Resources Information Center

    Lewis, Michael; Ramsay, Douglas

    2005-01-01

    This study examined the relation of infant emotional responses of anger and sadness to cortisol response in 2 goal blockage situations. One goal blockage with 4-month-old infants (N=56) involved a contingency learning procedure where infants' learned response was no longer effective in reinstating an event. The other goal blockage with 6-month-old…

  1. Workgroup for Hydraulic laboratory Testing and Verification of Hydroacoustic Instrumentation

    USGS Publications Warehouse

    Fulford, Janice M.; Armstrong, Brandy N.; Thibodeaux, Kirk G.

    2015-01-01

    An international workgroup was recently formed for hydraulic laboratory testing and verification of hydroacoustic instrumentation used for water velocity measurements. The activities of the workgroup have included one face to face meeting, conference calls and an inter-laboratory exchange of two acoustic meters among participating laboratories. Good agreement was found among four laboratories at higher tow speeds and poorer agreement at the lowest tow speed.

  2. The 2011 Tohoku earthquake sequences detected by IMS hydroacoustic array

    NASA Astrophysics Data System (ADS)

    Yun, S.; Lee, W.

    2011-12-01

    A Mw 9.1 thrust-fault earthquake has been occurred in the Pacific coast of Tohoku, Japan, on March 11, 2011. It is the fourth largest earthquake ever recorded since modern seismographs installed, and hundreds of strong aftershocks (M > 5) have been accompanied. We applied a cross-correlation method to the continuous data recorded in the Hawaii hydroacoustic array operated by International Monitoring System (IMS), and calculated back-azimuths of T-waves generated by the earthquake sequences. The back-azimuth values of the major events show somewhat scattered pattern, which is a different feature from that of the Great Sumatra-Andaman Earthquake. This may imply that the rupture is not likely to propagate linearly through the thrust fault line. Several aftershocks, however, clearly show gradual back-azimuthal change toward North. These differences might be caused by complex and diverse source mechanisms of the earthquakes. Combining hydroacoustic data obtained by other IMS hydroacoustic stations, if available, we could resolve a better azimuthal change regarding the earthquake sequence.

  3. Pipeline Blockage Unplugging and Locating Equipment

    SciTech Connect

    W. Thor Zollinger; Frank Carney

    2004-03-01

    This paper describes the development of a pulsed hydraulic system, specifically designed to unblock plugged piping. It uses the differences between the resonant vibrations of the fluid column and pipe walls to separate the blockage from the pipe wall, break it up, and clear the line. Using resonant frequencies, the system can stay below the design pressure of the system, preventing pipe failures from occurring, which is a major concern with DOE radioactive waste transfer lines.

  4. Long-range Hydroacoustic Detection From Antarctic Icebergs

    NASA Astrophysics Data System (ADS)

    Talandier, J.; Hyvernaud, O.; Piserchia, P. F.; Okal, E. A.

    T-waves are commonly observed on coastal seismographs of the French Polynesian Seismic Network (RSP), when an oceanic events like earthquake or an underwater ex- plosion occurs, even for small events. T-waves are trapped in the underwater channel and can propagate over very long distances before to be converted in seismic waves close to the coastal seismic stations. During the 2000/2001 Austral summer, coastal seismic stations of the RSP detected unique series of T-waves from Antarctica (about 60 away) in the frequency band 2 -15 Hz. Some last just a few minutes while other wavetrains last for several hours; some are broadband while others feature promi- nent frequencies, occasionally accompanied by overtones. Most of the hydroacoustic sources are relocated using the RSP stations and some Antarctic seismographs. It is shown that observed waves have an underwater path but may also propagate in the ice sheet. This paper investigates possible underwater sources using the wave form in their relocations. Because of the wide spread area of the source location in the Ross sea and the large diversity of signature and their spectral content, all well known hy- droacoustic sources (earthquakes, underwater explosions, volcanisms,E) are rejected. Whereas satellite monitoring shows that hydroacoustic source locations are very well correlated in space and in time with icebergs B-15B and B-17 moving off the Ross Ice Shelf. These two icebergs appear after the Iceberg B15 broke from the Ross Ice Shelf in March 2000. Therefore, we believe that signals detected on the RSP network may be due to due to activity during the drift of the bergs. From the experience achieved studying hydroacoustic sources like volcanic and hydrothermal phenomena, we pro- pose a few possible, albeit speculative source mechanisms, such the cracking of the icebergs, rubbing of ice masses against each other, or possible resonance during the filling of cavities inside the ice structures.

  5. Nonlinear interaction of atmospheric, surface-gravity, and hydroacoustic waves

    NASA Astrophysics Data System (ADS)

    Kadri, Usama

    2016-04-01

    We discuss the generation of hydroacoustic waves by the mutual interaction of atmospheric and surface-gravity waves, through nonlinear resonant triad interaction. To this end, we consider a two fluid problem, with a half-space air layer over a compressible water layer of finite depth, and a rigid bottom. The governing equations comprise a quadratic compressible wave equation, and the standard associated boundary conditions. Using a multiple scale approach we derive at the amplitude evolution equations for all three triad members. It is shown that the energy input by the atmospheric wave is transferred to the acoustic mode, with no noticeable effect on the surface gravity mode.

  6. Characterization of earthquake rupture characteristics using hydroacoustic data

    NASA Astrophysics Data System (ADS)

    de Groot-Hedlin, C.

    2006-12-01

    Hydroacoustic signals (T-waves) generated by the 2004 Great Sumatra earthquake were recorded by a network of 5 small hydroacoustic arrays located in the Indian Ocean at distances of 2800 to 7000 km from the epicenter. The array configurations allow for accurate determination of the receiver to source azimuth given coherent arrivals. Analysis of a series of short time windows within the T-wave coda shows that the receiver to source azimuth varies smoothly as a function of time, suggesting a non-stationary T-wave source. The data indicate that the rupture proceeded in two distinct phases; initially it progressed northwest at approximately 2.4 km/s along the Sunda trench. At 600km from the epicenter the rupture slowed to approximately 1.5 km/s. However, T-waves generated by small earthquakes are also generated over a wide range of azimuths, reflecting seismic to acoustic over a broad expanse of the seafloor. Although the azimuthal variations for the great Sumatra event are shown to be inconsistent with a small-scale source, it is difficult in general to distinguish between azimuthal variations associated with the physics of T-wave excitation and those associated with an extended rupture zone. A method of determining rupture length based on the apparent motion of the T-wave source location is presented here and applied to several events, including the Great Sumatra earthquake of Dec 26, 2004 and the magnitude 8.6 event of March 28, 2005.

  7. BLOCKAGE 2.5 user`s manual

    SciTech Connect

    Rao, D.V.; Brideau, J.; Shaffer, C.; Souto, F.; Bernahl, W.

    1996-12-01

    The BLOCKAGE 2.5 code described in this User`s Manual was developed by the US Nuclear Regulatory Commission (NRC) as a tool to evaluate licensee compliance with NRC Bulletin 96-03, ``Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors.`` As such, BLOCKAGE 2.5 provides a generalized framework into which a user can input plant-specific and insulation-specific data for performing analyses in accordance with Regulatory Guide 1.82, Rev. 2. This user`s manual describes the capabilities of BLOCKAGE 2.5 along with a description of the graphics user`s interface provided for data entry. Each input/output dialog is described in detail along with special considerations related to developing and executing BLOCKAGE. Also, several sample problems are provided such that user can easily modify them to suit a particular plant of interest. The models used in BLOCKAGE 2.5 and their validation are presented in the accompanying NUREG/CR-6371. The BLOCKAGE models were designed to be parametric in nature, allowing the user flexibility to examine the impact of several modeling assumptions and to conduct sensitivity analyses. As a result, BLOCKAGE 2.5 results are known to be very sensitive to the user provided input. It is therefore strongly recommended that users become thoroughly familiar with BLOCKAGE models and their limitations as described in NUREG/CR-6224.

  8. Multi-sensor investigation of the Sumatran Tsunami: observations and analysis of hydroacoustic, seismic, infrasonic, and tide gauge data

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, J.; Pulli, J.; Gibson, R.; Upton, Z.

    2005-05-01

    We present an analysis of the acoustic signals from the December 26, 2004 Sumatra earthquakes, in conjunction with the seismic and tide gauge information from the event. The M9.0 mainshock and its aftershocks were recorded by a suite of seismic sensors around the globe, giving us information on its location and the source process. Recently installed sensor assets in the Indian Ocean have enabled us to study additional features of this significant event. Hydroacoustic signals were recorded by three hydrophone arrays, and the direction finding capability of these arrays allows us to examine the location, time and extent of the T-wave generation process. We detect a clear variation of the back-azimuth that is consistent with the spatial extent of the source rupture. Recordings from nearly co-located seismometers provide insights into the acoustic-to-seismic conversion process for T-waves at islands, along with the variation in signal characteristics with source size. Two separate infrasound arrays detect the atmospheric signals generated by the event, along with additional observations of the seismic surface wave and the T-phase. We will present a comparison of the signals from the mainshock, as a function of location and size, with those from aftershocks and similar events in the nearby region. Our acoustic observations compare favorably with model predictions of wave propagation in the region. For the hydroacoustic data, the azimuth, arrival time, and signal blockage characteristics, from three separate arrays, associate the onset of the signal with the mainshock and with a time extent consistent with the rupture propagation. Our analysis of the T-phase travel times suggests that the seismic-to-acoustic conversion occurs more than 100 km from the epicenter. The infrasound signal's arrival time and signal duration are consistent with both stratospheric and thermospheric propagation from a source region near the mainshock. We use the tide gauge data from stations

  9. Preliminary Results from an Hydroacoustic Experiment in the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Royer, J.; Dziak, R. P.; Delatre, M.; Brachet, C.; Haxel, J. H.; Matsumoto, H.; Goslin, J.; Brandon, V.; Bohnenstiehl, D. R.; Guinet, C.; Samaran, F.

    2008-12-01

    We report initial results from a 14-month hydroacoustic experiment in the Indian Ocean conducted by CNRS/University of Brest and NOAA/Oregon State University. The objective was to monitor the low-level seismic activity associated with the three contrasting spreading ridges and deforming zones in the Indian Ocean. Three autonomous hydrophones, moored in the SOFAR channel, were deployed in October 2006 and recovered early 2008 by R/V Marion Dufresne, in the Madagascar Basin, and northeast and southwest of Amsterdam Island, complementing the two permanent hydroacoustic stations of the Comprehensive nuclear-Test-Ban Treaty Organization (CTBTO) located near Diego Garcia Island and off Cape Leeuwin. Our temporary network detected more than 2000 events. Inside the array, we located 592 events (compared to 49 in the NEIC earthquake catalog) with location errors less than 5 km and time error less than 2s. The hydrophone array detected on average 5 to 40 times more events per month than land-based networks. First-order observations indicate that hydroacoustic seismicity along the Southeast Indian ridge (SEIR) occurs predominantly along the transform faults. The Southwest Indian Ridge exhibits some periodicity in earthquake activity between adjacent ridge segments. Two large tectonic/volcanic earthquake swarms are observed along the Central Indian Ridge (near the triple junction) in September and December 2007. Moreover, many off ridge-axis events are also observed both south and north of the SEIR axis. Improved localization using the CTBTO records will help refine these preliminary results and further investigate extended volcanic sequences along the SEIR east of 80°E and other events outside of the temporary array. The records also display numerous vocalizations of baleen whales in the 20-40Hz bandwidth. The calls are attributed to fin whales, Antarctic blue whales and pygmy blue whales of Madagascar and Australian type. Their vocal activity is found to be highly seasonal

  10. Optimization of Hydroacoustic Equipment Deployments at Lookout Point and Cougar Dams, Willamette Valley Project, 2010

    SciTech Connect

    Johnson, Gary E.; Khan, Fenton; Ploskey, Gene R.; Hughes, James S.; Fischer, Eric S.

    2010-08-18

    The goal of the study was to optimize performance of the fixed-location hydroacoustic systems at Lookout Point Dam (LOP) and the acoustic imaging system at Cougar Dam (CGR) by determining deployment and data acquisition methods that minimized structural, electrical, and acoustic interference. The general approach was a multi-step process from mount design to final system configuration. The optimization effort resulted in successful deployments of hydroacoustic equipment at LOP and CGR.

  11. Optimal and adaptive methods of processing hydroacoustic signals (review)

    NASA Astrophysics Data System (ADS)

    Malyshkin, G. S.; Sidel'nikov, G. B.

    2014-09-01

    Different methods of optimal and adaptive processing of hydroacoustic signals for multipath propagation and scattering are considered. Advantages and drawbacks of the classical adaptive (Capon, MUSIC, and Johnson) algorithms and "fast" projection algorithms are analyzed for the case of multipath propagation and scattering of strong signals. The classical optimal approaches to detecting multipath signals are presented. A mechanism of controlled normalization of strong signals is proposed to automatically detect weak signals. The results of simulating the operation of different detection algorithms for a linear equidistant array under multipath propagation and scattering are presented. An automatic detector is analyzed, which is based on classical or fast projection algorithms, which estimates the background proceeding from median filtering or the method of bilateral spatial contrast.

  12. Seismic and hydroacoustic analysis relevant to MH370

    SciTech Connect

    Stead, Richard J.

    2014-07-03

    The vicinity of the Indian Ocean is searched for open and readily available seismic and/or hydroacoustic stations that might have recorded a possible impact of MH370 with the ocean surface. Only three stations are identified: the IMS hydrophone arrays H01 and H08, and the Geoscope seismic station AIS. Analysis of the data from these stations shows an interesting arrival on H01 that has some interference from an Antarctic ice event, large amplitude repeating signals at H08 that obscure any possible arrivals, and large amplitude chaotic noise at AIS precludes any analysis at higher frequencies of interest. The results are therefore rather inconclusive but may point to a more southerly impact location within the overall Indian Ocean search region. The results would be more useful if they can be combined with any other data that are not readily available.

  13. Hydroacoustic Studies Using HydroCAM - Station-centric Integration of Models and Observations Quarterly Report No.4 July 2003 - September 2003

    SciTech Connect

    Upton, Zachary, M.; Pulli, Jay, J.

    2003-10-13

    OAK B272 Quarterly technical report summarizing BBN's efforts to improve DOE's hydroacoustic modeling and analysis capability for nuclear explosion monitoring. BBN's work during the third quarter of 2003 was focused on preparations for and participation in the 2003 Seismic Research Review Meeting, unit testing and bug fixes to HydroCAM 4.1, data collection and analysis, and procuring high-resolution bathymetric data. In an attempt to save money, BBN scaled back its labor in the third quarter, delaying some deliverables but saving contract funding in case our next increment is delayed. We have succeeded in finding the correct Naval contact that can help us procure high-resolution bathymetry data. Although these data may require the release of a classified version of HydroCAM, we are optimistic that we will be able to acquire and integrate high-resolution bathymetric data near the Indian Ocean IMS stations. HydroCAM 4.1, which includes the ability to make blockage predictions using varying resolution bathymetric data, has completed unit testing and is now under integration (release) testing. We hope to deliver that functionality to DOE and AFTAC in November. BBN improved its database of hydroacoustic events in the Indian Ocean by including meta-data for associated arrivals. For each earthquake event, BBN is now picking the direct arrival at each station (Diego Garcia North and South, and Cape Leeuwin) and associating that arrival with the origin information that we are compiling. The data for 2001, 2002 and 2003 (to date) will be delivered to LLNL for integration into the Knowledge Base during the fourth quarter of 2003.

  14. Blockage of vibrissae afferents: I. Motor effects.

    PubMed

    Prchal, A; Albarracín, A L; Décima, E E

    2004-02-01

    In the past, it has been proposed that the rat vibrissae play an important role in other hand, postural abnormalities, muscle tone decreases and hypomotility after sensory organ destructions were proposed as evidence supporting the "level setting" or "tonic" hypothesis. This hypothesis postulates that afferent activity, besides its well know transductive functions, sets the excitability state of the central nervous system. We thought the vibrissal system to be a good model to dissect these two postulated roles because vibrissae trimming would annul the transductive function without affecting the integrity of nerve activity. Thus we compare the effects of trimming the whiskers with blocking the vibrissal afferent nerves on two types of motor behavior: activity in an open field and walking over a rope connecting two elevated platforms. We found that only vibrissal afferent blockage (both nerve section and local anaesthesia) produced severe failures in the motor performances studied. These effects could not be fully explained by the abolition of the vibrissae as a sensory modality because cutting the whiskers did not significantly affect the motor performance. These data are discussed in reference to a tonic or general excitatory function of sensory inputs upon the central nervous system. PMID:15143620

  15. Structural determinants of proton blockage in aquaporins.

    PubMed

    Chakrabarti, Nilmadhab; Roux, Benoît; Pomès, Régis

    2004-10-15

    Aquaporins are an important class of membrane channels selective for water and linear polyols but impermeable to ions, including protons. Recent computational studies have revealed that the relay of protons through the water-conduction pathway of aquaporin channels is opposed by a substantial free energy barrier peaking at the signature NPA motifs. Here, free-energy simulations and continuum electrostatic calculations are combined to examine the nature and the magnitude of the contribution of specific structural elements to proton blockage in the bacterial glycerol uptake facilitator, GlpF. Potential of mean-force profiles for both hop and turn steps of structural diffusion in the narrow pore are obtained for artificial variants of the GlpF channel in which coulombic interactions between the pore contents and conserved residues Asn68 and Asn203 at the NPA signature motifs, Arg206 at the selectivity filter, and the peptidic backbone of the two half-helices M3 and M7, which are arranged in head-to-head fashion around the NPA motifs, are turned off selectively. A comparison of these results with electrostatic energy profiles for the translocation of a probe cation throughout the water permeation pathway indicates that the free-energy profile for proton movement inside the narrow pore is dominated by static effects arising from the distribution of charged and polar groups of the channel, whereas dielectric effects contribute primarily to opposing the access of H+ to the pore mouths (desolvation penalty). The single most effective way to abolish the free-energy gradients opposing the movement of H+ around the NPA motif is to turn off the dipole moments of helices M3 and M7. Mutation of either of the two NPA Asn residues to Asp compensates for charge-dipole and dipole-dipole effects opposing the hop and turn steps of structural diffusion, respectively, and dramatically reduces the free energy barrier of proton translocation, suggesting that these single mutants could

  16. Hydroacoustic Signals Recorded by the International Monitoring System

    NASA Astrophysics Data System (ADS)

    Blackman, D.; de Groot-Hedlin, C.; Orcutt, J.; Harben, P.

    2002-12-01

    Networks of hydrophones, such as the hydroacoustic part of the International Monitoring System (IMS), and hydrophone arrays, such as the U.S. Navy operates, record many types of signals, some of which travel thousands of kilometers in the oceanic sound channel. Abyssal earthquakes generate many such individual events and occasionally occur in swarms. Here we focus on signals generated by other types of sources, illustrating their character with recent data, mostly from the Indian Ocean. Shipping generates signals in the 5-40 Hz band. Large airgun arrays can generate T-waves that travel across an ocean basin if the near-source seafloor has appropriate depth/slope. Airgun array shots from our 2001 experiment were located with an accuracy of 25-40 km at 700-1000 km ranges, using data from a Diego Garcia tripartite sensor station. Shots at greater range (up to 4800 km) were recorded at multiple stations but their higher background noise levels in the 5-30 Hz band resulted in location errors of ~100 km. Imploding glass spheres shattered within the sound channel produce a very impulsive arrival, even after propagating 4400 km. Recordings of the sphere signal have energy concentrated in the band above 40 Hz. Natural sources such as undersea volcanic eruptions and marine mammals also produce signals that are clearly evident in hydrophone recordings. For whales, the frequency range is 20~120Hz and specific patterns of vocalization characterize different species. Volcanic eruptions typically produce intense swarms of acoustic activity that last days-weeks and the source area can migrate tens of kms during the period. The utility of these types of hydroacoustic sources for research and/or monitoring purposes depends on the accuracy with which recordings can be used to locate and quantitatively characterize the source. Oceanic weather, both local and regional, affect background noise levels in key frequency bands at the recording stations. Databases used in forward modeling of

  17. Discharge Measurements in Shallow Urban Streams Using a Hydroacoustic Current Meter

    USGS Publications Warehouse

    Fisher, G.T.; Morlock, S.E.

    2002-01-01

    Hydroacoustic current-meter measurements were evaluated in small urban streams under a range of stages, velocities, and channel-bottom materials. Because flow in urban streams is often shallow, conventional mechanical current-meter measurements are difficult or impossible to make. The rotating-cup Price pygmy meter that is widely used by the U.S. Geological Survey and other agencies should not be used in depths below 0.20 ft and velocities less than 0.30 ft/s. The hydroacoustic device provides measurements at depths as shallow as 0.10 ft and velocities as low as 0.10 ft/s or less. Measurements using the hydroacoustic current meter were compared to conventional discharge measurements. Comparisons with Price-meter measurements were favorable within the range of flows for which the meters are rated. Based on laboratory and field tests, velocity measurements with the hydroacoustic cannot be validated below about 0.07 ft/s. However, the hydroacoustic meter provides valuable information on direction and magnitude of flow even at lower velocities, which otherwise could not be measured with conventional measurements.

  18. Hydroacoustic Evaluation of Fish Passage Through Bonneville Dam in 2002

    SciTech Connect

    Ploskey, Gene R. ); Schilt, Carl R.; Kim, J; Escher, Charles; Skalski, John R.

    2003-08-15

    The Portland District of the U.S. Army Corps of Engineers requested that the Pacific Northwest National Laboratory (PNNL) and the U.S. Army Engineer Research and Development Center (ERDC) conduct fish-passage studies at Bonneville Dam in 2002. The ERDC contracted with MEVATEC Corporation to provide staff ranging from scientists to technicians to help conduct the study. This study supports the Portland-District goal of maximizing fish-passage efficiency (FPE) and obtaining 95% survival for juvenile salmon passing Bonneville Dam. In this report, we present results of two studies of juvenile salmonid passage at Bonneville Dam that we carried out in the 2002 downstream passage season April 20 through July 15, 2002. The first study of Project-wide FPE provides hourly estimates of fish passage and associated variances for all operating turbine units, spill bays, and the two sluiceway entrances at Powerhouse 1 (B1), as well as estimates of a variety of fish-passage efficiency and effectiveness measures. This was the third consecutive year of full-project hydroacoustic sampling and passage estimation. The second study was more narrowly focused on B2 turbines and had two components: (1) to sample the FGE at two modified turbine intakes and compare them with efficiencies of other B2 units that were sampled in the first study, and (2) to evaluate proportions of fish passing up into gatewell slots versus through screen gaps at a few B2 turbine intakes.

  19. Modelling distribution of marine benthos from hydroacoustics and underwater video

    NASA Astrophysics Data System (ADS)

    Holmes, K. W.; Van Niel, K. P.; Radford, B.; Kendrick, G. A.; Grove, S. L.

    2008-08-01

    Broad-scale mapping of marine benthos is required for marine resource management and conservation. This study combines textural derivatives based on bathymetry from multibeam hydroacoustics with underwater video observations to model and map sessile biota between 10- and 60-m water depth over 35 km 2 in Point Addis Marine National Park (MNP), Vic., Australia. Classification tree models and maps were developed for macroalgae (all types, mixed red algae, Ecklonia, and rhodoliths) and sessile invertebrates (all types, sponges, and ascidians). Model accuracy was tested on 25% of the video observation dataset reserved from modelling. Models fit well for most macroalgae categories (correct classification rates of 67-84%), but are not as good for sessile invertebrate classes (correct classification rates of 57-62%). The poor fit of the sessile invertebrate models may be the combined result of grouping organisms with different environmental requirements and the effect of false absences recorded during video interpretation due to poor image quality. Probability maps, binary single-class maps, and multi-class maps supply spatially explicit, detailed information on the distribution of sessile benthic biota within the MNP and provide information at a landscape-scale for ecological investigations and marine management.

  20. Advanced neutron source reactor probabilistic flow blockage assessment

    SciTech Connect

    Ramsey, C.T.

    1995-08-01

    The Phase I Level I Probabilistic Risk Assessment (PRA) of the conceptual design of the Advanced Neutron Source (ANS) Reactor identified core flow blockage as the most likely internal event leading to fuel damage. The flow blockage event frequency used in the original ANS PRA was based primarily on the flow blockage work done for the High Flux Isotope Reactor (HFIR) PRA. This report examines potential flow blockage scenarios and calculates an estimate of the likelihood of debris-induced fuel damage. The bulk of the report is based specifically on the conceptual design of ANS with a 93%-enriched, two-element core; insights to the impact of the proposed three-element core are examined in Sect. 5. In addition to providing a probability (uncertainty) distribution for the likelihood of core flow blockage, this ongoing effort will serve to indicate potential areas of concern to be focused on in the preliminary design for elimination or mitigation. It will also serve as a loose-parts management tool.

  1. The Ascension Island hydroacoustic experiment: purpose, data set features and plans for future analysis

    SciTech Connect

    Harben, P E; Rock, D; Rodgers, A J

    1999-07-23

    Calibration of hydroacoustic and T-phase stations for Comprehensive Nuclear-Test-Ban Treaty (CTBT) monitoring will be an important element in establishing new operational stations and upgrading existing stations. Calibration of hydroacoustic stations is herein defined as precision location of the hydrophones and determination of the amplitude response from a known source energy. T-phase station calibration is herein defined as a determination of station site attenuation as a function of frequency, bearing, and distance for known impulsive energy sources in the ocean. To understand how to best conduct calibration experiments for both hydroacoustic and T-phase stations, an experiment was conducted in May, 1999 at Ascension Island in the South Atlantic Ocean. The experiment made use of a British oceanographic research vessel and collected data that will be used for CTBT issues and for fundamental understanding of the Ascension Island volcanic edifice.

  2. Hydroacoustic propagation grids for the CTBT knowledge databaes BBN technical memorandum W1303

    SciTech Connect

    J. Angell

    1998-05-01

    The Hydroacoustic Coverage Assessment Model (HydroCAM) has been used to develop components of the hydroacoustic knowledge database required by operational monitoring systems, particularly the US National Data Center (NDC). The database, which consists of travel time, amplitude correction and travel time standard deviation grids, is planned to support source location, discrimination and estimation functions of the monitoring network. The grids will also be used under the current BBN subcontract to support an analysis of the performance of the International Monitoring System (IMS) and national sensor systems. This report describes the format and contents of the hydroacoustic knowledgebase grids, and the procedures and model parameters used to generate these grids. Comparisons between the knowledge grids, measured data and other modeled results are presented to illustrate the strengths and weaknesses of the current approach. A recommended approach for augmenting the knowledge database with a database of expected spectral/waveform characteristics is provided in the final section of the report.

  3. An overview of the BWR ECCS strainer blockage issues

    SciTech Connect

    Serkiz, A.W.; Marshall, M.L. Jr.; Elliott, R.

    1996-03-01

    This Paper provides a brief overview of actions taken in the mid 1980s to resolve Unresolved Safety Issue (USI) A-43, {open_quotes}Containment Emergency Sump Performance,{close_quotes} and their relationship to the BWR strainer blockage issue; the importance of insights gained from the Barseback-2 (a Swedish BWR) incident in 1992 and from ECCS strainer testing and inspections at the Perry nuclear power plant in 1992 and 1993; an analysis of an US BWR/4 with a Mark I containment; an international community sharing of knowledge relevant to ECCS strainer blockage, additional experimental programs; and identification of actions needed to resolve the strainer blockage issue and the status of such efforts.

  4. Pipeline blockage location by strain measurement using an ROV

    SciTech Connect

    Rogers, L.M.

    1995-12-31

    The paper describes an ROV based inspection method for locating a blockage in a marine pipeline. The method measures changes in the hoop strain in the pipe corresponding to changes in the internal fluid pressure. The device (patent applied for), converts radial extension or compression of the pipe into axial compression or tension respectively of a load cell. It allows the use of a high sensitivity axial strain sensing element to measure the hoop strain in the pipe. By pressurizing the pipe at positions upstream and downstream of the blockage and measuring the resulting hoop strain, the boundaries of the blockage can be accurately defined. The device can be installed and recovered by ROV, the signals being relayed to the surface via the ROV`s umbilical. The method has been used successfully to locate and define the extent of a blockage in a deepwater oil flowline running from a satellite well system to a production platform, allowing the planning of effective remedial action. The results of the strain measurements were found to be fully consistent with the contents of the pipe determined by subsequent sectioning. Key features of the hoop strain device include rugged design, high sensitivity, ease of attachment and recovery by ROV with the need for minimal cleaning and for access only to a sector of the pipe, typically {1/4} the circumference.

  5. Maximization of noise immunity of a two-layer hydroacoustic antenna

    NASA Astrophysics Data System (ADS)

    Smaryshev, M. D.

    2008-09-01

    A method of maximizing the noise immunity coefficient of a two-layer hydroacoustic antenna is proposed. An antenna consisting of two parallel linear arrays is considered as an example to estimate the gain in noise immunity achieved with the proposed algorithm against the cardioid-type connection of these arrays.

  6. Research of the performance of pulse electrohydrodynamics in blockage removal.

    PubMed

    Jevtić, Milenko; Milojković, Ivan; Stojnić, Nedeljko

    2011-01-01

    In line with contemporary trends and seeking to develop new methods and technologies, a new, original technology was explored and designed based on a non-conventional process of electrical pulse discharge in a water chamber, referred to as 'Pulse Electrohydrodynamic Technology' (PELHYDT). The application of the PELHYDT in sewer blockage removal is presented in this paper. Existing machinery can remove two blockages of gully pot connections per hour. Three blockages of pipe conduits are generally removed during an 8-h working day. Applying PELHYDT technology, which allows for high rates of removal of mechanical obstructions, it is possible to achieve operating fluid pressures in the order of 10(3)-10(4) bars, a velocity of 100 m/s, a deformation acceleration of the model material structure of 10(6)-10(7) m/s2, and high-frequency hydraulic shock waves with a frequency of 10(3)-10(4) Hz. The applicability of this efficient technology in sewer blockage removal was proven under laboratory conditions at operating fluid pressures from 50 to 160 bars, which are standard for sewer maintenance. Water velocities generally achieved in sewers using existing flushing technologies range between 1 and 3 m/s and usually do not exceed 9 m/s. PELHYDT creates waves whose velocity is at least 100 m/s, and is therefore about ten times more efficient than existing technologies. PELHYDT generates an electrohydrodynamic wave very quickly, virtually in the form of an explosion. It was proven under laboratory conditions that the application of this technology for blockage removal in practice will not result in any sewer damage. PMID:22053463

  7. Relations of Early Goal-Blockage Response and Gender to Subsequent Tantrum Behavior

    ERIC Educational Resources Information Center

    Sullivan, Margaret W.; Lewis, Michael

    2012-01-01

    Infants and their mothers participated in a longitudinal study of the sequelae of infant goal-blockage responses. Four-month-old infants participated in a standard contingency learning and goal-blockage procedure during which anger and sad facial expressions to the blockage were coded. When infants were 12 and 20 months old, mothers completed a…

  8. Infertility caused by tubal blockage: An ayurvedic appraisal.

    PubMed

    Shukla Upadhyaya, Kamayani; Karunagoda, Kaumadi; Dei, L P

    2010-04-01

    Tubal blockage is one of the most important factors for female infertility. This condition is not described in Ayurvedic classics, as the fallopian tube itself is not mentioned directly there. The present study is an effort to understand the disease according to Ayurvedic principles. Correlating fallopian tubes with the Artavavaha (Artava-bija-vaha) Srotas, its block is compared with the Sanga Srotodushti of this Srotas. Charak's opinion that the diseases are innumerable and newly discovered ones should be understood in terms of Prakriti, Adhishthana, Linga, and Aayatana, is followed, to describe this disease. An effort has been made to evaluate the role of all the three Doshas in producing blockage, with classification of the disease done as per the Dasha Roganika. PMID:22131704

  9. Infertility caused by tubal blockage: An ayurvedic appraisal

    PubMed Central

    Shukla (Upadhyaya), Kamayani; Karunagoda, Kaumadi; Dei, L. P.

    2010-01-01

    Tubal blockage is one of the most important factors for female infertility. This condition is not described in Ayurvedic classics, as the fallopian tube itself is not mentioned directly there. The present study is an effort to understand the disease according to Ayurvedic principles. Correlating fallopian tubes with the Artavavaha (Artava-bija-vaha) Srotas, its block is compared with the Sanga Srotodushti of this Srotas. Charak's opinion that the diseases are innumerable and newly discovered ones should be understood in terms of Prakriti, Adhishthana, Linga, and Aayatana, is followed, to describe this disease. An effort has been made to evaluate the role of all the three Doshas in producing blockage, with classification of the disease done as per the Dasha Roganika. PMID:22131704

  10. Hydroacoustic estimation of zooplankton biomass at two shoal complexes in the Apostle Islands Region of Lake Superior

    USGS Publications Warehouse

    Holbrook, B.V.; Hrabik, T.R.; Branstrator, D.K.; Yule, D.L.; Stockwell, J.D.

    2006-01-01

    Hydroacoustics can be used to assess zooplankton populations, however, backscatter must be scaled to be biologically meaningful. In this study, we used a general model to correlate site-specific hydroacoustic backscatter with zooplankton dry weight biomass estimated from net tows. The relationship between zooplankton dry weight and backscatter was significant (p < 0.001) and explained 76% of the variability in the dry weight data. We applied this regression to hydroacoustic data collected monthly in 2003 and 2004 at two shoals in the Apostle Island Region of Lake Superior. After applying the regression model to convert hydroacoustic backscatter to zooplankton dry weight biomass, we used geostatistics to analyze the mean and variance, and ordinary kriging to create spatial zooplankton distribution maps. The mean zooplankton dry weight biomass estimates from plankton net tows and hydroacoustics were not significantly different (p = 0.19) but the hydroacoustic data had a significantly lower coefficient of variation (p < 0.001). The maps of zooplankton distribution illustrated spatial trends in zooplankton dry weight biomass that were not discernable from the overall means.

  11. Transcription blockage by stable H-DNA analogs in vitro.

    PubMed

    Pandey, Shristi; Ogloblina, Anna M; Belotserkovskii, Boris P; Dolinnaya, Nina G; Yakubovskaya, Marianna G; Mirkin, Sergei M; Hanawalt, Philip C

    2015-08-18

    DNA sequences that can form unusual secondary structures are implicated in regulating gene expression and causing genomic instability. H-palindromes are an important class of such DNA sequences that can form an intramolecular triplex structure, H-DNA. Within an H-palindrome, the H-DNA and canonical B-DNA are in a dynamic equilibrium that shifts toward H-DNA with increased negative supercoiling. The interplay between H- and B-DNA and the fact that the process of transcription affects supercoiling makes it difficult to elucidate the effects of H-DNA upon transcription. We constructed a stable structural analog of H-DNA that cannot flip into B-DNA, and studied the effects of this structure on transcription by T7 RNA polymerase in vitro. We found multiple transcription blockage sites adjacent to and within sequences engaged in this triplex structure. Triplex-mediated transcription blockage varied significantly with changes in ambient conditions: it was exacerbated in the presence of Mn(2+) or by increased concentrations of K(+) and Li(+). Analysis of the detailed pattern of the blockage suggests that RNA polymerase is sterically hindered by H-DNA and has difficulties in unwinding triplex DNA. The implications of these findings for the biological roles of triple-stranded DNA structures are discussed. PMID:26101261

  12. Hydroacoustic observations of Indian earthquake provide new data on T-waves

    NASA Astrophysics Data System (ADS)

    Pulli, Jay J.; Upton, Zachary M.

    The magnitude 7.8 earthquake that devastated the Bhuj area of western India on 26 January 2001 was recorded not only by seismometers around the world, but also by a new hydroacoustic array in the Indian Ocean. This array, located 3290 km south of the epicentral area (see Figure 1a), consists of two tripartite hydrophone arrays surrounding the atoll of Diego Garcia at the southern end of the Chagos Plateau. Installed as part of the hydroacoustic monitoring network for the Comprehensive Nuclear Test Ban Treaty's International Monitoring System (IMS), the array has since been recording the acoustic T-wave signals generated by many shallow earthquakes below the Indian Ocean since the summer of 2000.

  13. Development and validation of hydroacoustic monitoring concepts for the coastal German Bight (SE North Sea)

    NASA Astrophysics Data System (ADS)

    Mielck, Finn; Hass, H. Christian; Holler, Peter; Bartholomä, Alexander; Neumann, Andreas; Kröncke, Ingrid; Reimers, Hans-Christian; Capperucci, Ruggero

    2016-04-01

    The joint research project WIMO (Wissenschaftliche Monitoringkonzepte für die Deutsche Bucht/Scientific Monitoring Concepts for the German Bight, NE North Sea) aims at providing methods for detection and analysis of seabed habitats using modern remote sensing techniques. Our subproject focuses on hydroacoustic techniques in order to gain information about seafloor environments and sediment dynamics. In a timeframe of four years, several key areas in the German Bight were repeatedly observed using different hydroacoustic gear (i. e. sidescan sonars, single/multibeam echo sounders and sub-bottom profilers). In order to ground-truth the acoustic data, hundreds of grab samples and underwater videos were taken. With these techniques it is possible to distinguish between different seafloor habitats, which range from muddy to sandy seafloors (esp. near the barrier islands) to rugged or vegetated/populated reefs around Helgoland. The conducted monitoring program revealed seasonal changes regarding the abundance of the sand mason worm (Lanice conchilega) and the brittle star (Amphiora filiformis) as well as ongoing sedimentary processes driven by tidal currents and wind/storms. It was also possible to determine relationships between sediment characteristics and benthos in some key areas. An essential part of our project included a comparison between the datasets obtained with different hydroacoustic devices, configurations, and evaluation methods in the same study areas. The investigation reveals that there could be distinct differences in interpreting the data and hence in the determination of prevailing seafloor habitats, especially in very heterogeneous areas and at transition zones between the habitats. Therefore, it is recommended to employ more than one hydroacoustic system (preferably a singlebeam device combined with a wide-swath sonar system) synchronously during a survey in order to gain more reliable and detailed information about the seafloor environments. The

  14. Hydroacoustic Observations of the Western India Earthquake of Jan. 26, 2001 and It's Aftershocks

    NASA Astrophysics Data System (ADS)

    Pulli, J. J.; Upton, Z. M.

    2001-05-01

    The magnitude 7.7 Mw earthquake that devastated the Gujarat area of western India on January 26, 2001 was recorded not only by seismometers around the world but also by a new hydroacoustic array in the Indian Ocean. This array, located 3280 km south of the epicentral area, consists of two tripartite hydrophone arrays surrounding the atoll of Diego Garcia at the southern end of the Chagos Plateau. Installed as part of the hydroacoustic monitoring system for the Comprehensive Test Ban Treaty's International Monitoring System, the array came online in the summer of 2000 and has since been recording the acoustic signals generated by numerous earthquakes below the Indian Ocean. Since the Gujarat earthquake was located near the coast of India at a crustal depth of only 20-km, upgoing seismic energy was able to couple to acoustic energy along the continental slope and reach the SOFAR channel to produce T-waves that were recorded at Diego Garcia. Additionally, the teleseismic P-wave arriving below the array was also of sufficient energy to couple acoustic energy into the water column. Spectral energy of the waterborne T-waves at Diego reaches 50 Hz, with most of the energy in the 2-10 Hz band. The teleseismically coupled acoustic energy reaches only about 5 Hz. Using the time delays between array components at Diego, we are able to calculate back azimuths of the hydroacoustic and seismic arrivals and separate direct arrivals from the source area with those of the aftershocks and reflected signals produced by bathymetric features in the Indian Ocean. Travel times also provide some constraint on the location of the area where seismic energy couples into T-waves along the continental slope. Numerous aftershocks of the 7.7 earthquake were also recorded by the Diego Garcia array and hence provide a means of testing the scaling relationship between seismic and hydroacoustic energy. From this data, we estimate that an earthquake as small as magnitude 3 in the Gujarat epicentral

  15. Hydroacoustic monitoring of a salt cavity: analysis of precursory events of the collapse

    NASA Astrophysics Data System (ADS)

    Lebert, François; Bernardie, Séverine; Mainsant, Guénolé

    2010-05-01

    One of the main purposes in "post mining" research is related to the available methods and means for monitoring mine-degradation processes that may, as a consequence, directly threaten surface infrastructures. GISOS, a French scientific interest group concerned with the impact and the safety of the underground works in the field of the post-mining, aims amongst other at developing techniques for monitoring underground growing cavities due to salt dissolution, leading to collapse. One method for monitoring the stability of a salt cavity is to record microseismic-precursor signals that indicate the onset of rock failure. In particular, in this study, it has to identify and evaluate the capacity of hydroacoustic technique for monitoring salt cavities. More specifically, the purpose is to be able to determine the criteria of the behaviour change and the state of the rock likely to occur as a precursory sign before the collapse of the salt cavity. More precisely, three types of signal were recorded in a salt mine, in Lorraine (France), during the monitoring of the collapse of a salt cavity of about 800.000 m3 at 120 m depth. - The RMS (Root Mean Square) levels, with the time recordings of the RMS power in four frequency-bands (total signal; 30 Hz - 3 kHz; 3 kHz - 30 kHz; 30 kHz - 180 kHz). - The low frequency monitoring, which records the events from cracking to block falls, in the 30 Hz - 3 kHz frequency-band? - The high frequency monitoring, which deals with the recordings of events occurring in the 30 kHz - 180 kHz frequency-band? The hydroacoustic data highlight some interesting precursory signals before the collapse of the cavity. Indeed, the cumulative energy evolution of both low and high frequency events seems to be a good indicator of the mechanical state of the cavity. Moreover, the analysis of the recordings shows a new type of family events, which occurs a few hours before the failure phase. Finally, correlations have been performed between hydroacoustic

  16. Hydroacoustic monitoring of a salt cavity: analysis of precursory events of the collapse

    NASA Astrophysics Data System (ADS)

    Bernardie, S.; Lebert, F.; Mainsant, G.

    2009-12-01

    One of the main purposes in "post mining" research is related to the available methods and means for monitoring mine-degradation processes that may, as a consequence, directly threaten surface infrastructures. GISOS, a French scientific interest group concerned with the impact and the safety of the underground works in the field of the post-mining, aims amongst other at developing techniques for monitoring underground growing cavities due to salt dissolution, leading to collapse. One method for monitoring the stability of a salt cavity is to record microseismic-precursor signals that indicate the onset of rock failure. In particular, in this study, it has to identify and evaluate the capacity of hydroacoustic technique for monitoring salt cavities. More specifically, the purpose is to be able to determine the criteria of the behaviour change and the state of the rock likely to occur as a precursory sign before the collapse of the salt cavity. More precisely, three types of signal are investigated: - The RMS (Root Mean Square) levels, with the time recordings of the RMS power in four frequency-bands (total signal; 30 Hz - 3 kHz; 3 kHz - 30 kHz; 30 kHz - 180 kHz). - The low frequency monitoring, which records the events from cracking to block falls, in the 30 Hz - 3 kHz frequency-band. - The high frequency monitoring, which deals with the recordings of events occurring in the 30 kHz - 180 kHz frequency-band. The hydroacoustic data highlight some interesting precursory signals before the collapse of the cavity. Indeed, the cumulative energy evolution of both low and high frequency events seems to be a good indicator of the mechanical state of the cavity. Moreover, the analysis of the recordings shows a new type of family events, which occurs a few hours before the failure phase. Finally, correlations have been performed between hydroacoustic recordings and other measurements acquired at the same time on the site, including strain measurements, and hydrostatic pressure

  17. Coulomb blockage of hybridization in two-dimensional DNA arrays

    NASA Astrophysics Data System (ADS)

    Vainrub, Arnold; Pettitt, B. Montgomery

    2002-10-01

    Experiments on DNA microarrays have revealed substantial differences in hybridization thermodynamics between DNA free in solution and surface tethered DNA. Here we develop a mean field model of the Coulomb effects in two-dimensional DNA arrays to understand the binding isotherms and thermal denaturation of the double helix. We find that the electrostatic repulsion of the assayed nucleic acid from the array of DNA probes dominates the binding thermodynamics, and thus causes the Coulomb blockage of the hybridization. The results explain, observed in DNA microarrays, the dramatic decrease of the hybridization efficiency and the thermal denaturation curve broadening as the probe surface density grows. We demonstrate application of the theory for evaluation and optimization of the sensitivity, specificity, and the dynamic range of DNA array devices.

  18. AREVA Team Develops Sump Strainer Blockage Solution for PWRs

    SciTech Connect

    Phan, Ray

    2006-07-01

    The purpose of this paper is to discuss the methodology, testing challenges, and results of testing that a team of experts from Areva NP, Alden Research Laboratory, Inc (ALDEN), and Performance Contracting Inc. (PCI) has developed. The team is currently implementing a comprehensive solution to the issue of Emergency Core Cooling System (ECCS) sump strainer blockage facing Pressurized Water Reactor (PWR) Nuclear Plants. The team has successfully demonstrated two key results from the testing of passive Sure-FlowTM strainers, which were designed to distribute the required flow over a large surface area resulting in extremely low approach velocities. First, the actual head loss (pressure drop) as tested, across the prototype strainers, was much lower than the calculated head loss using the Nuclear Regulatory Commission (NRC) approved NUREG/CR-6224 head loss correlation. Second, the penetration fractions were much lower than those seen in the NRC sponsored debris penetration tests. (author)

  19. Validation of Blockage Interference Corrections in the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    Walker, Eric L.

    2007-01-01

    A validation test has recently been constructed for wall interference methods as applied to the National Transonic Facility (NTF). The goal of this study was to begin to address the uncertainty of wall-induced-blockage interference corrections, which will make it possible to address the overall quality of data generated by the facility. The validation test itself is not specific to any particular modeling. For this present effort, the Transonic Wall Interference Correction System (TWICS) as implemented at the NTF is the mathematical model being tested. TWICS uses linear, potential boundary conditions that must first be calibrated. These boundary conditions include three different classical, linear. homogeneous forms that have been historically used to approximate the physical behavior of longitudinally slotted test section walls. Results of the application of the calibrated wall boundary conditions are discussed in the context of the validation test.

  20. Translation with secondary structure: Dynamic blockages in totally asymmetric simple exclusion process

    NASA Astrophysics Data System (ADS)

    Shaw, Leah

    2011-03-01

    The totally asymmetric simple exclusion process (TASEP) is often used as a model for protein synthesis, with the lattice and particles representing the mRNA and ribosomes, respectively. Here we model the effect of secondary structure (folding) of the mRNA by introducing a dynamic blockage region in the lattice. If the region is unoccupied by particles, the blockage can close and prevent upstream particles from moving into it, representing the folding of that section of mRNA. Reopening of the blockage, allowing particles to pass, represents unfolding. We study the effects of the blockage size, closing/opening probabilities, and TASEP parameters on the particle current and blockage switching rates.

  1. Developments in hot-film anemometry measurements of hydroacoustic particle motion

    NASA Astrophysics Data System (ADS)

    Dubbelday, Pieter S.; Apostolico, Virgil V.; Diebel, Dean L.

    1988-08-01

    Hot film anemometry may be used to measure particle motion in hydroacoustic fields. Since the cylindrical sensors used thus far are very fragile, the method is little suited for use outside the laboratory. The measurement of the response of a more rugged conical sensor is reported here. Another way of protecting the sensor consists of packaging the sensor in a rubber liquid filled boot. This also prevents fouling and bubble formation on the heated film. The response shows a resonance at low frequency, ascribed to the liquid filled boot, which may be used for enhanced response in a limited frequency region. The response of a hot film anemometer to vertical hydroacoustic particle motion is influenced by free convection, which acts as a bias flow. The output was shown to be proportional to particle displacement for a wide range of parameters. It was expected that an imposed bias flow would increase the output and remove the dependence on the direction of gravity. Therefore, a hot-film sensor (diameter d) was subjected to an underwater jet from a nozzle. The output showed a transition from being proportional to particle speed, to being proportional to particle displacement, depending on the angular frequency omega and imposed flow speed omega. The transition takes place when a dimensionless number omega, defined as omega = omega/nu is of order 1.

  2. Hydroacoustic estimates of abundance and spatial distribution of pelagic prey fishes in western Lake Superior

    USGS Publications Warehouse

    Mason, Doran M.; Johnson, Timothy B.; Harvey, Chris J.; Kitchell, James F.; Schram, Stephen T.; Bronte, Charles R.; Hoff, MIchael H.; Lozano, Stephen J.; Trebitz, Anett S.; Schreiner, Donald R.; Lamon, E. Conrad; Hrabik, Thomas R.

    2005-01-01

    Lake herring (Coregonus artedi) and rainbow smelt (Osmerus mordax) are a valuable prey resource for the recovering lake trout (Salvelinus namaycush) in Lake Superior. However, prey biomass may be insufficient to support the current predator demand. In August 1997, we assessed the abundance and spatial distribution of pelagic coregonines and rainbow smelt in western Lake Superior by combining a 120 kHz split beam acoustics system with midwater trawls. Coregonines comprised the majority of the midwater trawl catches and the length distributions for trawl caught fish coincided with estimated sizes of acoustic targets. Overall mean pelagic prey fish biomass was 15.56 kg ha−1 with the greatest fish biomass occurring in the Apostle Islands region (27.98 kg ha−1), followed by the Duluth Minnesota region (20.22 kg ha−1), and with the lowest biomass occurring in the open waters of western Lake Superior (9.46 kg ha−1). Biomass estimates from hydroacoustics were typically 2–134 times greater than estimates derived from spring bottom trawl surveys. Prey fish biomass for Lake Superior is about order of magnitude less than acoustic estimates for Lakes Michigan and Ontario. Discrepancies observed between bioenergetics-based estimates of predator consumption of coregonines and earlier coregonine biomass estimates may be accounted for by our hydroacoustic estimates.

  3. Hydroacoustic simulation of rotor-stator interaction in resonance conditions in Francis pump-turbine

    NASA Astrophysics Data System (ADS)

    Nicolet, C.; Ruchonnet, N.; Alligné, S.; Koutnik, J.; Avellan, F.

    2010-08-01

    Combined effect of rotating pressure field related to runner blade and wakes of wicket gates leads to rotor stator interactions, RSI, in Francis pump-turbines. These interactions induce pressures waves propagating in the entire hydraulic machine. Superposition of those pressure waves may result in standing wave in the spiral casing and rotating diametrical mode in the guide vanes and can cause strong pressure fluctuations and vibrations. This paper presents the modeling, simulation and analysis of Rotor-Stator Interaction of a scale model of a Francis pump-turbine and related test rig using a one-dimensional approach. The hydroacoustic modeling of the Francis pump-turbine takes into account the spiral casing, the 20 guide vanes, the 9 rotating runner vanes. The connection between stationary and rotating parts is ensured by a valve network driven according to the unsteady flow distribution between guide vanes and runner vanes. Time domain simulations are performed for 2 different runner rotational speeds in turbine mode. The simulation results are analyzed in frequency domain and highlights hydroacoustic resonance between RSI excitations and the spiral case. Rotating diametrical mode in the vaneless gap and standing wave in the spiral case are identified. The influence of the resonance on phase and amplitude of pressure fluctuations obtained for both the spiral case and the vaneless gap is analyzed. The mode shape and frequencies are confirmed using eigenvalues analysis.

  4. Formation of Hydro-acoustic Waves in Dissipative Coupled Weakly Compressible Fluids

    NASA Astrophysics Data System (ADS)

    Abdolali, A.; Kirby, J. T., Jr.; Bellotti, G.

    2014-12-01

    Recent advances in deep sea measurement technology provide an increasing opportunity to detect and interpret hydro-acoustic waves as a component in improved Tsunami Early Warning Systems (TEWS). For the idealized case of a homogeneous water column above a moving but otherwise rigid bottom (in terms of assessing acoustic wave interaction), the description of the infinite family of acoustic modes is characterized by local water depth at source area; i.e. the period of the first acoustic mode is given by four times the required time for sound to travel from the seabed to the surface. Spreading off from earthquake zone, the dominant spectrum is filtered and enriched by seamounts and barriers. This study focuses on the characteristics of hydro-acoustic waves generated by sudden sea bottom motion in a weakly compressible fluid coupled with an underlying sedimentary layer, where the added complexity of the sediment layer rheology leads to both the lowering of dominant spectral peaks and wave attenuation across the full spectrum. To overcome the computational difficulties of three-dimensional models, we derive a depth integrated equation valid for varying water depth and sediment thickness. Damping behavior of the two layered system is initially taken into account by introducing the viscosity of fluid-like sedimentary layer. We show that low frequency pressure waves which are precursor components of tsunamis contain information of seafloor motion.

  5. Comparing hydroacoustic and T-phases from terrestrial and ocean-bottom recordings around La Réunion Island, Indian Ocean

    NASA Astrophysics Data System (ADS)

    Snelling, Branwen; Sigloch, Karin; Barruol, Guilhem; Ferrazzini, Valérie

    2016-04-01

    A survey of hydroacoustic signals detected on an array of 57 OBS stations in the Indian Ocean is presented. The OBSs were capable of recording broadband signals (0.01 Hz to 25 Hz). They covered a diverse geological setting, and ranged to depths as great as 5500 m. Once hydroacoustic phases were identified they were cross referenced with an earthquake catalogue in order to confirm their association with seismic activity. The results of this survey revealed 20 hydroacoustic events throughout the 13-month dataset, which were detected at 20 or more stations in the OBS network. The characteristics of these hydroacoustic signals were compared to the characteristics of T-phases, which propagated through the SOFAR channel to a coast-proximal seismic land station on La Réunion island. The waveforms, durations, and spectral contents of hydroacoustic and T-phase signals were similar. A power comparison revealed that the magnitudes of T-phases at the island stations were up to two orders of magnitude greater than the magnitudes of hydroacoustic arrivals at OBS stations at a similar distance from the seismic event. Despite this, hydroacoustic phases were observed on the OBS stations up to 10,000 km distance. A modeling investigation attempted to constrain the propagation mechanism by which hydroacoustic energy was reaching the deep ocean. Ray tracing revealed that in order for a ray to contribute energy to an arrival at an OBS it would have to reflect or diffract at extreme water depths, below the SOFAR waveguide. These observations imply that hydroacoustic arrivals on OBS stations can be used over teleseismic ranges just like T-phase observations on land-based stations and hydrophones. A better understanding of the propagation mechanism of this energy to the deep ocean will be necessary to exploit their full potential.

  6. Scientific concepts for hydroacoustic seafloor mapping in the coastal zone and beyond

    NASA Astrophysics Data System (ADS)

    Hass, H. Christian; Bartholomä, Alexander; Bürk, Dietmar; Holler, Peter; Mielck, Finn; Reimers, Hans-Christian

    2013-04-01

    Hydroacoustic seafloor mapping is a reliable and cost-effective method to investigate and monitor the seafloor in high spatial and temporal resolution. The results are important for the evaluation of benthic habitats and help to identify vulnerable environments that require protection. Yet, how can we overcome the problems that occur when different gear produces different results, which are evaluated by people that have different points of view and different backgrounds? These aspects form an integer part of the project WIMO ("Scientific concepts for monitoring the German Bight, SE North Sea", Subproject 1.1: "Hydroacoustic Habitat Mapping"). It aims at comparing different hydroacoustic gear, methodologies and workflows in order to work out basic routines for universal use in marine benthic habitat mapping. The project investigates a number of target areas in the German Bight (North Sea) using different sidescan sonars (SSS), acoustic seafloor-classification systems (AGDS), multibeams, and different sampling and grain-size analytical methods as well as sea-floor imaging methods. We tested different gear on different ships, on the same ship but not synchronously, and as many instruments as possible measuring at the same time on the same ship. Our results suggest that guidelines and requirements for surveys can hardly be standardized as they depend largely on the water depth, the seabed, and on the vessel and the equipment available. All of these frame conditions usually differ from survey to survey. Taking this into account, we present a reasonable workflow for time and cost-effective benthic habitat mapping and monitoring. Transect-line distances as well as monitoring frequencies, number and positioning of ground-truth samples and seabed imaging are discussed. We recommend frequency combinations and appropriate swath widths and overlaps for SSS and show a way to ground-truth lower-frequency data using high-frequency data. Acoustic ground discrimination systems are

  7. Use of hydroacoustic measurements to characterize bottom sediments and guide sampling and remediation of organic contaminants in lake sediments.

    PubMed

    Anderson, Michael A; Conkle, Jeremy L; Pacheco, Porfirio; Gan, Jay

    2013-08-01

    Sampling of bed sediment for contamination characterization is often limited by the heterogeneity in sediment properties and distribution. In this study, we explored the use of hydroacoustic measurements to characterize sediment properties and guide sediment sampling in a small lake contaminated by organochlorine pesticides (OCPs) and PCBs. A dual frequency hydroacoustic survey was conducted to characterize sediment properties, distribution, and thickness in McGrath Lake, near Ventura, CA. Based upon these results, sediment core samples were collected from 15 sites on the lake, and sectioned into 20 cm intervals for sediment characterization and analysis of OCPs and PCBs. Very high concentrations of total DDT and total chlordane were found in the sediments, with mean values of 919 and 34.9 ng g(-1), respectively. Concentrations of OCPs were highest at 60-80 cm depth near the inflow at the north end of the lake. Total PCB concentrations were much lower (mean concentration of 4.5 ng g(-1)). Using the hydroacoustic and chemical data, it was estimated that nearly 30,000 m(3) of DDT- and chlordane-contaminated sediment (above effects range median values) was present in the uppermost 1.2 m of sediment in the lake. A hydroacoustic survey can be a valuable tool used to delineate sediment distribution in a lake, identify areas with deeper organic sediment where hydrophobic contaminants would likely be found, and guide sampling. Sampling and chemical analyses are nonetheless needed to quantify contaminant levels in bottom sediments. When combined with hydroacoustic measurements, this approach can reasonably estimate the distributions and volumes of contaminated sediment important in the development of remediation strategies. PMID:23644565

  8. Rapid detection of sewer defects and blockages using acoustic-based instrumentation.

    PubMed

    Ali, M T Bin; Horoshenkov, K V; Tait, S J

    2011-01-01

    Sewer flooding incidents in the UK are being increasingly associated with the presence of blockages. Blockages are difficult to deal with as although there are locations where they are more likely to occur, they do occur intermittently. In order to manage sewer blockage pro-actively sewer managers need to be able to identify the location of blockages promptly. Traditional closed-circuit television (CCTV) inspection technologies are slow and relatively expensive so are not well suited to the rapid inspection of a network. This is needed if managers are to be able to address sewer blockages proactively. This paper reports on the development of an acoustic-based sensor. The sensor was tested in a full scale sewer pipe in the laboratory and it was shown that it is able to find blockages and identify structural aspects of a sewer pipe such as a manhole and lateral connection. Analysis of the received signal will locate a blockage and also provide information on its character. The measurement is very rapid and objective and so inspections can be carried out at much faster rates than using existing CCTV technologies. PMID:22335114

  9. Blockage effects on the hydrodynamic performance of a marine cross-flow turbine.

    PubMed

    Consul, Claudio A; Willden, Richard H J; McIntosh, Simon C

    2013-02-28

    This paper explores the influence of blockage and free-surface deformation on the hydrodynamic performance of a generic marine cross-flow turbine. Flows through a three-bladed turbine with solidity 0.125 are simulated at field-test blade Reynolds numbers, O(10(5)-10(6)), for three different cross-stream blockages: 12.5, 25 and 50 per cent. Two representations of the free-surface boundary are considered: rigid lid and deformable free surface. Increasing the blockage is observed to lead to substantial increases in the power coefficient; the highest power coefficient computed is 1.23. Only small differences are observed between the two free-surface representations, with the deforming free-surface turbine out-performing the rigid lid turbine by 6.7 per cent in power at the highest blockage considered. This difference is attributed to the increase in effective blockage owing to the deformation of the free surface. Hydrodynamic efficiency, the ratio of useful power generated to overall power removed from the flow, is found to increase with blockage, which is consistent with the presence of a higher flow velocity through the core of the turbine at higher blockage ratios. Froude number is found to have little effect on thrust and power coefficients, but significant influence on surface elevation drop across the turbine. PMID:23319712

  10. A database and model to support proactive management of sediment-related sewer blockages.

    PubMed

    Rodríguez, Juan Pablo; McIntyre, Neil; Díaz-Granados, Mario; Maksimović, Cedo

    2012-10-01

    Due to increasing customer and political pressures, and more stringent environmental regulations, sediment and other blockage issues are now a high priority when assessing sewer system operational performance. Blockages caused by sediment deposits reduce sewer system reliability and demand remedial action at considerable operational cost. Consequently, procedures are required for identifying which parts of the sewer system are in most need of proactive removal of sediments. This paper presents an exceptionally long (7.5 years) and spatially detailed (9658 grid squares--0.03 km² each--covering a population of nearly 7.5 million) data set obtained from a customer complaints database in Bogotá (Colombia). The sediment-related blockage data are modelled using homogeneous and non-homogeneous Poisson process models. In most of the analysed areas the inter-arrival time between blockages can be represented by the homogeneous process, but there are a considerable number of areas (up to 34%) for which there is strong evidence of non-stationarity. In most of these cases, the mean blockage rate increases over time, signifying a continual deterioration of the system despite repairs, this being particularly marked for pipe and gully pot related blockages. The physical properties of the system (mean pipe slope, diameter and pipe length) have a clear but weak influence on observed blockage rates. The Bogotá case study illustrates the potential value of customer complaints databases and formal analysis frameworks for proactive sewerage maintenance scheduling in large cities. PMID:22794800

  11. Integrated pore blockage-cake filtration model for crossflow filtration

    SciTech Connect

    Daniel, Richard C.; Billing, Justin M.; Russell, Renee L.; Shimskey, Rick W.; Smith, Harry D.; Peterson, Reid A.

    2011-07-01

    Crossflow filtration is to be a key process in the treatment and disposal of approximately 60,000 metric tons of high-level radioactive waste stored at the Hanford Site in Richland, Washington. Pacific Northwest National Laboratory is assessing filter performance with waste simulant materials that mimic the chemical and physical properties of Hanford tank waste. Prior simulant studies indicated that waste filtration performance may be limited by pore and cake fouling. To limit the shutdown of waste treatment operations, the pre-treatment facility plans to recover filter flux losses from cake formation and filter fouling by frequently backpulsing the filter elements. The objective of the current paper is to develop a simple model of flux decline resulting from cake and pore fouling and potential flux recovery through backpulsing of the filters for Hanford waste filtration operations. To this end, a model capable of characterizing the decline in waste-simulant filter flux as a function of both irreversible pore blockage and reversible cake formation is proposed. This model is used to characterize the filtration behavior of Hanford waste simulants in both continuous and backpulsed operations. The model is then used to infer the optimal backpulse frequency under specific operating conditions.

  12. Coral Patch seamount (NE Atlantic) - a sedimentological and megafaunal reconnaissance based on video and hydroacoustic surveys

    NASA Astrophysics Data System (ADS)

    Wienberg, C.; Wintersteller, P.; Beuck, L.; Hebbeln, D.

    2013-05-01

    The present study provides new knowledge about the so far largely unexplored Coral Patch seamount which is located in the NE Atlantic Ocean half-way between the Iberian Peninsula and Madeira. For the first time a detailed hydroacoustic mapping (MBES) in conjunction with video surveys (ROV, camera sled) were performed to describe the sedimentological and biological characteristics of this sub-elliptical ENE-WSW elongated seamount. Video observations were restricted to the southwestern summit area of Coral Patch seamount (water depth: 560-760 m) and revealed that this part of the summit is dominated by exposed hard substrate, whereas soft sediment is just a minor substrate component. Although exposed hardgrounds are dominant for this summit area and, thus, offer suitable habitat for settlement by benthic organisms, the benthic megafauna shows rather scarce occurrence. In particular, scleractinian framework-building cold-water corals are apparently rare with very few isolated and small-sized live occurrences of the species Lophelia pertusa and Madrepora oculata. In contrast, dead coral framework and coral rubble are more frequent pointing to a higher abundance of cold-water corals on Coral Patch during the recent past. This is even supported by the observation of fishing lines that got entangled with rather fresh-looking coral frameworks. Overall, long lines and various species of commercially important fish were frequently observed emphasising the potential of Coral Patch as an important target for fisheries that may have impacted the entire benthic community. Hydroacoustic seabed classification covered the entire summit of Coral Patch and its northern and southern flanks (water depth: 560-2660 m) and revealed extended areas dominated by mixed and soft sediments at the northern flank and to a minor degree at its easternmost summit and southern flank. Nevertheless, these data also predict most of the summit area to be dominated by exposed bedrock which would offer

  13. Coral Patch seamount (NE Atlantic) - a sedimentological and macrofaunal reconnaissance based on video and hydroacoustic surveys

    NASA Astrophysics Data System (ADS)

    Wienberg, C.; Wintersteller, P.; Beuck, L.; Hebbeln, D.

    2012-12-01

    The present study provides new knowledge about the so far largely unexplored Coral Patch seamount which is located in the NE Atlantic Ocean half-way between the Iberian Peninsula and Madeira. For the first time a detailed hydroacoustic mapping (MBES) in conjunction with video surveys (ROV, camera sled) were performed to describe the sedimentological and biological characteristics of this sub-elliptical ENE-WSW elongated seamount. Video observations were restricted to the south-western summit area of Coral Patch seamount (area: ~ 8 km2, water depth: 560-760 m) and revealed that this part of the summit is dominated by exposed hard substrate, whereas soft sediment is just a minor substrate component. Although exposed hardgrounds are dominant for this summit area, and thus, offer suitable habitat for settlement by benthic organisms, the macrofauna shows rather low abundance and diversity. In particular, scleractinian framework-building cold-water corals are apparently rare with very few isolated and small-sized live occurrences of the species Lophelia pertusa and Madrepora oculata. In contrast, dead coral framework and coral rubble are more frequent pointing to a higher abundance of cold-water corals on Coral Patch during the recent past. This is even supported by the observation of fishing lines that got entangled with rather fresh-looking coral frameworks. Overall, long lines and various species of commercially important fish were frequently observed emphasising the potential of Coral Patch as an important target for fisheries that may have impacted the entire benthic community. Hydroacoustic seabed classification covered the entire summit of Coral Patch and its northern and southern flanks (area: 560 km2; water depth: 560-2660 m) and revealed extended areas dominated by mixed and soft sediments at the northern flank and to a minor degree at its easternmost summit and southern flank. Nevertheless, also these data predict most of the summit area to be dominated by

  14. Hydroacoustic investigation of the emissions of gas from the seabed in fieldwork and experimental studies

    NASA Astrophysics Data System (ADS)

    Tomczyk, M.; Bohrmann, G.; Wright, I. C.; Sahling, H.; Waldmann, C.

    2012-04-01

    The investigation of the fate of rising bubbles from the seabed is of increasing importance, to be able to quantify the potential input to atmospheric methane (CH4). Hydroacoustic methods seem to be the most sensitive and reliable way to remotely determine bubble fluxes over a large area. The advantage of noninvasive remote sensing methods can be used to better understand the role of cold seep sites in global climate changes. During two cruises in 2011 (R/V Meteor cruise M84/2 in the Black Sea in February and RSS James Ross Clark JCR253 arctic cruise in August) a combination of several techniques was evaluated for detection, localization and classification of gas emissions from natural cold seeps, including a detailed hydroacoustic survey of investigated areas and data analysis with the use of specialized software. Acoustic data were collected using different echosounders and platforms: two multibeam systems EM122 and EM710, multifrequency echosounder EK60, and parametric narrow-beam Parasound echosunder. Detailed location maps of gas seeps, and 3D visualization models showing the registered flares were obtained. All hydroacoustic intruments provided evidence of acoustic anomalies in the water column, related to the strong impedance step between the free gas (bubbles) and the surrounding water. On echograms, rising bubbles often appear as flare-shaped reflections, simply called "flares". Most of these flares do not reach the sea-surface, nevertheless, some of gas bubble plumes rising up to several hundred meters above the seabed. Flares do not rise straight upwards but are deflected in a direction of current, which can be seen after processing multibeam echosounder data. Matlab codes were used in order to process data coming from EK60 fish-finder echosunder. These data can be used for quantification of gas bubble emissions. Bathymetry data sets exported from MB-System with 2 m horizontal resolution were examined in Fledermaus software for further cleaning

  15. Scale effects on propeller cavitating hydrodynamic and hydroacoustic performances with non-uniform inflow

    NASA Astrophysics Data System (ADS)

    Yang, Qiongfang; Wang, Yongsheng; Zhang, Zhihong

    2013-03-01

    Considering the lack of theoretical models and ingredients necessary to explain the scaling of the results of propeller cavitation inception and cavitating hydroacoustics from model tests to full scale currently, and the insufficient reflection of the nuclei effects on cavitation in the numerical methods, the cavitating hydrodynamics and cavitation low frequency noise spectrum of three geometrically similar 7-bladed highly skewed propellers with non-uniform inflow are addressed. In this process, a numerical bridge from the multiphase viscous simulation of propeller cavitation hydrodynamics to its hydro-acoustics is built, and the scale effects on performances and the applicability of exist scaling law are analyzed. The effects of non-condensable gas(NCG) on cavitation inception are involved explicitly in the improved Sauer's cavitation model, and the cavity volume acceleration related to its characteristic length is used to produce the noise spectrum. Results show that, with the same cavitation number, the cavity extension on propeller blades increases with diameter associated with an earlier shift of the beginning point of thrust decline induced by cavitation, while the three decline slopes of thrust breakdown curves are found to be nearly the same. The power of the scaling law based on local Reynolds number around 0.9 R section is determined as 0.11. As for the smallest propeller, the predominant tonal noise is located at blade passing frequency(BPF), whereas 2BPF for the middle and both 2BPF and 3BPF for the largest, which shows the cavitating line spectrum is fully related to the interaction between non-uniform inflow and fluctuated cavity volume. The predicted spectrum level exceedance from the middle to the large propeller is 6.65 dB at BPF and 5.94 dB at 2BPF. Since it just differs less than 2 dB to the increment obtained by empirical scaling law, it is inferred that the scale effects on them are acceptable with a sufficient model scale, and so do the

  16. Model based manipulator control

    NASA Technical Reports Server (NTRS)

    Petrosky, Lyman J.; Oppenheim, Irving J.

    1989-01-01

    The feasibility of using model based control (MBC) for robotic manipulators was investigated. A double inverted pendulum system was constructed as the experimental system for a general study of dynamically stable manipulation. The original interest in dynamically stable systems was driven by the objective of high vertical reach (balancing), and the planning of inertially favorable trajectories for force and payload demands. The model-based control approach is described and the results of experimental tests are summarized. Results directly demonstrate that MBC can provide stable control at all speeds of operation and support operations requiring dynamic stability such as balancing. The application of MBC to systems with flexible links is also discussed.

  17. Users guide for the hydroacoustic coverage assessment model (HydroCAM)

    SciTech Connect

    Farrell, T., LLNL

    1997-12-01

    A model for predicting the detection and localization performance of hydroacoustic monitoring networks has been developed. The model accounts for major factors affecting global-scale acoustic propagation in the ocean. including horizontal refraction, travel time variability due to spatial and temporal fluctuations in the ocean, and detailed characteristics of the source. Graphical user interfaces are provided to setup the models and visualize the results. The model produces maps of network detection coverage and localization area of uncertainty, as well as intermediate results such as predicted path amplitudes, travel time and travel time variance. This Users Guide for the model is organized into three sections. First a summary of functionality available in the model is presented, including example output products. The second section provides detailed descriptions of each of models contained in the system. The last section describes how to run the model, including a summary of each data input form in the user interface.

  18. Hydroacoustic Evaluation of Juvenile Salmonid Passage and Distribution at Lookout Point Dam, 2010

    SciTech Connect

    Khan, Fenton; Johnson, Gary E.; Royer, Ida M.; Hughes, James S.; Fischer, Eric S.; Trott, Donna M.; Ploskey, Gene R.

    2011-07-01

    This report presents the results of an evaluation of juvenile salmonid passage and distribution at Lookout Point Dam (LOP) on the Middle Fork Willamette River. The study was conducted by the Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers, Portland District (USACE). The goal of the study was to provide fish passage and distribution data to support decisions on long-term measures to enhance downstream passage at LOP and others dams in USACE’s Willamette Valley Project in response to the listing of Upper Willamette River Spring Chinook salmon (Oncorhynchus tshawytscha) and Upper Willamette River steelhead (O. mykiss) as threatened under the Endangered Species Act. During the year-long study period - February 1, 2010 to January 31, 2011the objectives of the hydroacoustic evaluation of fish passage and distribution at LOP were to: 1. Estimate passage rates, run timing, horizontal distribution, and diel distribution at turbine penstock intakes for smolt-size fish. 2. Estimate passage rates, run timing and diel distribution at turbine penstock intakes for small-size fish. 3. Estimate passage rates and run timing at the regulating outlets for smolt-size fish. 4. Estimate vertical distribution of smolt-size fish in the forebay near the upstream face of the dam. The fixed-location hydroacoustic technique was used to accomplish the objectives of this study. Transducers (420 kHz) were deployed in each penstock intake, above each RO entrance, and on the dam face; a total of nine transducers (2 single-beam and 7 split-beam) were used. We summarize the findings from the hydroacoustic evaluation of juvenile salmonid passage and distribution at LOP during February 2010 through January 2011 as follows. • Fish passage rates for smolt-size fish (> ~90 mm) were highest during December-January and lowest in mid-summer through early fall. • During the entire study period, an estimated total of 142,463 fish ± 4,444 (95% confidence interval) smolt

  19. A rich Internet application for automated detection of road blockage in post-disaster scenarios

    NASA Astrophysics Data System (ADS)

    Liu, W.; Dong, P.; Liu, S.; Liu, J.

    2014-02-01

    This paper presents the development of a rich Internet application for automated detection of road blockage in post-disaster scenarios using volunteered geographic information from OpenStreetMap street centerlines and airborne light detection and ranging (LiDAR) data. The architecture of the application on the client-side and server-side was described. The major functionality of the application includes shapefile uploading, Web editing for spatial features, road blockage detection, and blockage points downloading. An example from the 2010 Haiti earthquake was included to demonstrate the effectiveness of the application. The results suggest that the prototype application can effectively detect (1) road blockage caused by earthquakes, and (2) some human errors caused by contributors of volunteered geographic information.

  20. Cystine/glutamate antiporter blockage induces myelin degeneration.

    PubMed

    Soria, Federico N; Zabala, Alazne; Pampliega, Olatz; Palomino, Aitor; Miguelez, Cristina; Ugedo, Luisa; Sato, Hideyo; Matute, Carlos; Domercq, María

    2016-08-01

    The cystine/glutamate antiporter is a membrane transport system responsible for the uptake of extracellular cystine and release of intracellular glutamate. It is the major source of cystine in most cells, and a key regulator of extrasynaptic glutamate in the CNS. Because cystine is the limiting factor in the biosynthesis of glutathione, and glutamate is the most abundant neurotransmitter, the cystine/glutamate antiporter is a central player both in antioxidant defense and glutamatergic signaling, two events critical to brain function. However, distribution of cystine/glutamate antiporter in CNS has not been well characterized. Here, we analyzed expression of the catalytic subunit of the cystine/glutamate antiporter, xCT, by immunohistochemistry in histological sections of the forebrain and spinal cord. We detected labeling in neurons, oligodendrocytes, microglia, and oligodendrocyte precursor cells, but not in GFAP(+) astrocytes. In addition, we examined xCT expression and function by qPCR and cystine uptake in primary rat cultures of CNS, detecting higher levels of antiporter expression in neurons and oligodendrocytes. Chronic inhibition of cystine/glutamate antiporter caused high toxicity to cultured oligodendrocytes. In accordance, chronic blockage of cystine/glutamate antiporter as well as glutathione depletion caused myelin disruption in organotypic cerebellar slices. Finally, mice chronically treated with sulfasalazine, a cystine/glutamate antiporter inhibitor, showed a reduction in the levels of myelin and an increase in the myelinated fiber g-ratio. Together, these results reveal that cystine/glutamate antiporter is expressed in oligodendrocytes, where it is a key factor to the maintenance of cell homeostasis. GLIA 2016. GLIA 2016;64:1381-1395. PMID:27247047

  1. Hydroacoustic records of seafloor earthquakes, cryogenic sounds, and cetacean vocalizations in the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Chateau, R.; Royer, J.; Dziak, R. P.; Bohnenstiehl, D. R.; Brandon, V.; Haxel, J. H.

    2009-12-01

    From October 2006 to January 2008, three hydrophones were deployed in the southern Indian Ocean by the CNRS/University of Brest and the NOAA/Oregon State University. These hydrophones were moored in the SOFAR channel and recorded a total of 1780 discrete acoustic events, mainly earthquakes from the mid-ocean ridges and cryogenic acoustic signals from off Antarctica (due to ice shelf creeping and iceberg breaking). The low attenuation of acoustic waves in the SOFAR channel allows for the long-range detection of low-magnitude earthquakes (body-magnitude < 3), thus highly increasing the detection threshold compared to terrestrial seismic networks in the region. Our temporary hydroacoustic array complemented the 2 permanent stations of the Comprehensive nuclear Test-Ban Treaty Organization (CTBTO) located near Diego Garcia Island and off Cape Leeuwin (Australia). Combining the records from the whole array significantly increased the coverage and accuracy of the event locations, and resulted in the detection of more than 9100 events during the same period. The new catalogue consists in 4377 ice-related events coming from the Antarctica margin and 3848 earthquakes located along the three Indian spreading ridges and the Java-Sumatra trench. Hydroacoustic records show an impressive variety of signals and locations. The seismogenic signals results from earthquakes activity in a variety of tectonic settings : Mid-ocean ridges spreading at variable rates, as well as transform faults, subduction zones, and intraplate deformation. The ice-quake activity, including tremor-like signals with clear harmonics, is typically located near Antarctica along the Wilkes Land coast and shows a seasonal variation. The hydrophone records also show seasonally varying biogenic signals caused by the vocalizations of 3 different cetacean species, including blue, fin, and Milke whales.

  2. Area-wide seafloor mapping in the SE North Sea using hydroacoustics

    NASA Astrophysics Data System (ADS)

    Mielck, Finn; Hass, H. Christian

    2013-04-01

    Mapping seafloor properties has become increasingly important for understanding marine ecosystems and providing basic data for sustainable management. However, the knowledge regarding the distribution of seabed environments in the German part of the North Sea is still fragmentary. It is mainly derived from single case studies and from a 1:250,000 scale map based on grab samples published in 1981. In recent years, hydroacoustic devices became a powerful tool to quickly obtain reliable information of the seafloor. In the years 2007-2012 various hydroacoustic surveys were performed in order to map the seafloor in the coastal zone of the NE German Bight comprising an area of approximately 1,500 km². Measurements were carried out with a sidescan sonar (Imagenex YellowFin, 330 kHz) at a resolution of 25 cm. For ground truthing several hundred sediment samples were taken. The seafloor in the investigation area is mainly characterized by fine and medium sand. West off Sylt relics of former Pleistocene moraines stretch perpendicular to the coast in westerly directions. These relics consist of wide bands of coarse to medium sand and are basically linked to the morphological structures such as ridges and channels. The truncated push moraines from the Saalian glacial represent the seaward extension of the recent moraine core ('Geest') of Sylt. In addition a great number of smaller scaled structures, generally known as sorted bedforms were detected. Sidescan sonography of the same area carried out in two consecutive years reveals that these bedforms are dynamic and therefore subject to flow-directed movement across the seafloor. They are linked with large-scale sediment transport that occurs in this highly dynamic area as a result of vigorous tidal currents. Ongoing investigations aim at relating the occurrence of different bedforms to current speed and net sediment transport direction to calculate sediment budget. These govern erosion and accumulation processes that are

  3. Hydroacoustic Evaluation of Fish-Passage Efficiency at Bonneville Dam in 2001

    SciTech Connect

    Ploskey, Gene R.; Schilt, Carl R.; Hanks, Michael E.; Johnson, Peter N.; Kim, Jina; Skalski, John R.; Patterson, Deborah S.; Nagy, William T.; Lawrence, Larry R.

    2002-10-11

    The Portland District of the U.S. Army Corps of Engineers requested that scientists with the Pacific Northwest National Laboratory (PNNL) and the U.S. Army Engineer Research and Development Center (ERDC) conduct the hydroacoustic fish-passage studies described in this report. The ERDC also contracted with MEVATEC Corporation and Dyntel to provide staff ranging from scientists to technicians for the study. This study supports the Portland-District goal of maximizing fish passage efficiency (FPE) and obtaining 95% survival for juvenile salmon passing the Bonneville Project. This report presents results of two hydroacoustic studies of juvenile salmonids. One was a Project-wide study of fish-passage efficiency, and the other was more narrowly focused upon the approach, vertical distribution, and fish-guidance efficiency (FGE) of fish at Unit 15, where the Portland District extensively modified the gatewell and vertical barrier screen to improve gatewell flow and FGE. The goal of the larger of the two studies was to provide project-wide estimates of FPE, spill efficiency, and spill effectiveness for run-of-river fish passing the Bonneville Project during the 2001 out-migration. This type of study also provides estimates of the horizontal, vertical, and diel distributions of fish passage and FGE by turbine unit. These data will provide a baseline for evaluating the performance of future management efforts to improve juvenile fish passage. The goal of the second study was to assess the effect of gatewell and vertical-barrier-screen modifications on the FGE of Unit 15.

  4. Hydroacoustic and spatial analysis of sediment fluxes and accumulation rates in two Virginia reservoirs, USA.

    PubMed

    Clark, E V; Odhiambo, B K; Yoon, S; Pilati, L

    2015-06-01

    Watershed sediment fluxes and reservoir sediment accumulation rates were analyzed in two contrasting reservoir systems in central and western Virginia. Lake Pelham, located in the Piedmont geologic province, is a human-impacted reservoir with a watershed dominated by agricultural, residential and industrial land uses. Conversely, Lake Moomaw has a largely undeveloped watershed characterized by very steep slopes and forested land use located in the Valley and Ridge province. The Revised Universal Soil Loss Equation (RUSLE) and sediment delivery ratios (SDRs) were used to estimate soil losses in the two watersheds. Bathymetric and sediment accumulation surveys of the two reservoirs were also conducted using a multi-frequency hydroacoustic surveying system. The RUSLE/SDR erosion model estimates 2150 kg ha(-1) year(-1) for Lake Pelham and 2720 kg ha(-1) year(-1) for Lake Moomaw, a 410 and 13 % increase from assumed pristine (100 % forested) land use for the respective basins. Mean sediment accumulation rates of 1.51 and 0.60 cm year(-1) were estimated from the hydroacoustic survey of Lake Pelham and Lake Moomaw, respectively. Overall, Lake Moomaw has relatively low sediment accumulation rates; however, the reservoir is vulnerable to increases in sediment fluxes with further human development due to the steep slopes and highly erodible colluvial soils that characterize the basin. Higher erosion and sediment accumulation rates in Lake Pelham are most likely reflecting the impact of human development on sedimentation processes, where the loss of vegetal buffers and increase in impervious surfaces exacerbates both the surficial soil losses as well as intrinsic stream sediment production leading to the current annual reservoir capacity loss of 0.4 %. PMID:25563837

  5. Hydroacoustic measures of Mysis relicta abundance and distribution in Lake Ontario

    USGS Publications Warehouse

    Rudstam, L. G.; Schaner, T.; Gal, G.; Boscarino, B.T.; O'Gorman, R.; Warner, D.M.; Johannsson, O.E.; Bowen, K.L.

    2008-01-01

    Mysis relicta can be observed on echograms as a sound scattering layer when they migrate into the water column at night to feed on zooplankton. However, quantitative measures of mysid abundance with hydroacoustics requires knowledge of mysid target strength (TS), a method of removing fish echoes and contribution from noise, and an understanding of the effect of range on the ability of hydroacoustics to detect mysids (the detection limit). Comparisons of paired net data and acoustics data from July 7, 2005 yielded a mysid TS of -86.3 dB (9 mm animal) and a biomass TS of -58.4 dB (g dry wt)-1. With ambient noise levels (Sv of -125 dB at 1 m depth) and this TS, we can detect a mysid density of 1 m-3 at 60 m depth with a signal to noise ratio of 3 dB. We present a method to remove backscattering from both noise and fish and apply this method and the new TS data to whole lake acoustic data from Lake Ontario collected in July 25-31, 2005 with a 120 kHz echosounder as part of the annual standard fish survey in that lake. Mysis abundance was strongly depth dependent, with highest densities in areas with bottom depth > 100 m, and few mysids in areas with bottom depth 100 m, 100-75 m, 75-50 m, 50-30 m, < 30 m), the whole-lake average mysid density was 118 m-2 (CV 21%) and the whole-lake average mysid biomass was 0.19 g dry wt m-2 (CV 22%) in July 2005. The CVs of these densities also account for uncertainty in the TS estimates. This is comparable to whole-lake density estimates using vertical net tows in November, 2005 (93 m-2, CV 16%). Copyright ?? 2008 AEHMS.

  6. Hydroacoustic Evaluation of Juvenile Salmonid Passage at The Dalles Dam Spillway, 2006

    SciTech Connect

    Johnson, Gary E.; Khan, Fenton; Skalski, John R.; Rakowski, Cynthia L.; Richmond, Marshall C.; Serkowski, John A.

    2007-05-24

    The objective of this study was to determine detailed vertical, horizontal, intensive, and diel distributions of juvenile salmonid passage at the spillway at The Dalles Dam from April 12 to July16, 2006. These data are being applied in the Spillway Improvements Program to position release pipes for direct injury and mortality studies and to provide baseline data for assessment of the vortex suppression devices scheduled for deployment in 2007. We estimated fish distributions from hydroacoustic data collected with split-beam transducers arrayed across Bays 1 through 9 and 14. Spill at ~20 kcfs per bay was bulked at Bays 1-6, although the other bays were opened at times during the study to maintain a 40% spill percentage out of total project discharge. The vertical distribution of fish was skewed toward the surface during spring, but during summer, passage peaked at 2-3 m above the spillway ogee. Fish passage rates (number per hour) and fish densities (number per kcfs) were highest at Bay 6, followed by passage at Bay 5. This result comports with spillway horizontal distribution data from radio telemetry and hydroacoustic studies in 2004. The vertical and horizontal distribution of fish passage at bays 5 and 6 was much more variable during spring than summer and more variable at bay 5 than bay 6. Diel distribution data revealed that fish passage was highest during 0600-0700 h in spring; otherwise passage was reasonably uniform on a diel basis. This study substantiates the purpose of the spillway vortex suppression device to re-distribute downstream migrants away from Bay 6 toward Bays 1-5.

  7. Efficacy of Yavakshara Taila Uttarabasti in the management of fallopian tube blockage

    PubMed Central

    Baria, Hetal P.; Donga, Shilpa B.; Dei, Laxmipriya

    2015-01-01

    Introduction: Tubal blockage is one of the most common causative factors for female barrenness. It accounts for about 25-35% of female infertility. It is very difficult to manage, as the treatment choices for it are only tubal re-constructive surgery and in vitro fertilization (IVF). On the other hand, there is not established any reliable Ayurvedic treatment for the tubal blockage. It is the need of the time to establish an efficient and cost-effective therapy for this problem. Aim: To evaluate the efficacy of Yavakshara Taila Uttarabasti in fallopian tubal blockage. Materials and Methods: Patients of childbearing age with active marital life of 1 year or more, having complaint of failure to conceive with at least one fallopian tube blockage were selected. Total 19 patients were registered with 42.11% unilateral and 57.89% bilateral tubal blockage. Yavakshara Taila (5 ml) Intrauterine Uttarabasti was given for 6 days (with interval of 3 days in between), after completion of menstrual cycle for two consecutive cycles. Results: The tubal patency was found in 68.75% of patients and conception was achieved in 6.25% of patients. Conclusion: Yavakshara Taila Uttarabasti an effective procedure for treating tubal blockage with no apparent evidence of complication. PMID:26730135

  8. The field of a point source in an inhomogeneous hydroacoustic waveguide with a body drifting on the surface

    NASA Astrophysics Data System (ADS)

    Papkova, Yu. I.

    2015-07-01

    A three-dimensional analytic solution is constructed for the model of an inhomogeneous hydroacoustic waveguide with a cylindrically shaped body drifting on the surface. A numerically analytic method is proposed to find the velocity potential for which the unknown coefficients for normal modes are determined from the corresponding infinite system of linear algebraic equations. The amplitude-frequency characteristics of the waveguide are studied as a function of the model parameters.

  9. Blockage of mitochondrial calcium uniporter prevents iron accumulation in a model of experimental subarachnoid hemorrhage

    SciTech Connect

    Yan, Huiying; Hao, Shuangying; Sun, Xiaoyan; Zhang, Dingding; Gao, Xin; Yu, Zhuang; Li, Kuanyu; Hang, Chun-Hua

    2015-01-24

    Highlights: • Iron accumulation was involved in the acute phase following SAH. • Blockage of MCU could attenuate cellular iron accumulation following SAH. • Blockage of MCU could decrease ROS generation and improve cell energy supply following SAH. • Blockage of MCU could alleviate apoptosis and brain injury following SAH. - Abstract: Previous studies have shown that iron accumulation is involved in the pathogenesis of brain injury following subarachnoid hemorrhage (SAH) and chelation of iron reduced mortality and oxidative DNA damage. We previously reported that blockage of mitochondrial calcium uniporter (MCU) provided benefit in the early brain injury after experimental SAH. This study was undertaken to identify whether blockage of MCU could ameliorate iron accumulation-associated brain injury following SAH. Therefore, we used two reagents ruthenium red (RR) and spermine (Sper) to inhibit MCU. Sprague–Dawley (SD) rats were randomly divided into four groups including sham, SAH, SAH + RR, and SAH + Sper. Biochemical analysis and histological assays were performed. The results confirmed the iron accumulation in temporal lobe after SAH. Interestingly, blockage of MCU dramatically reduced the iron accumulation in this area. The mechanism was revealed that inhibition of MCU reversed the down-regulation of iron regulatory protein (IRP) 1/2 and increase of ferritin. Iron–sulfur cluster dependent-aconitase activity was partially conserved when MCU was blocked. In consistence with this and previous report, ROS levels were notably reduced and ATP supply was rescued; levels of cleaved caspase-3 dropped; and integrity of neurons in temporal lobe was protected. Taken together, our results indicated that blockage of MCU could alleviate iron accumulation and the associated injury following SAH. These findings suggest that the alteration of calcium and iron homeostasis be coupled and MCU be considered to be a therapeutic target for patients suffering from SAH.

  10. Bacteria detection based on its blockage effect on silicon nanopore array.

    PubMed

    Tang, Yanyan; Li, Zhen; Luo, Qiaohui; Liu, Jingqing; Wu, Jianmin

    2016-05-15

    Bacteria detection plays an important role in the guarantee of food and water safety. This work proposed a new sensing strategy for the rapid detection of bacteria based on its blockage effect on nanopore array, which was prepared from electrochemically etched silicon. With the assistance of microfluidic technology, the nanopore array attached with Escherichia coli antibody can selectively and rapidly capture E. coli bacteria, resulting in the decrease of pore accessibility. The signal of pore blockage can be measured by in-direct Fourier Transformed Reflectometric Interference Spectroscopy (FT-RIS). The pore blockage signal has a linear relationship with the logarithm of bacterial density in aqueous sample within the range from 10(3) to 10(7)cfuml(-1). Due to the specific interaction between the antibody and target bacteria, only the E. coli sample displayed significant pore blockage effect, whereas the non-target bacteria, Nox and P17, almost did not show any pore blockage effect. The strategy established in this work might be pervasively applied in the rapid detection of target bacteria and cell in a label-free manner. PMID:26774087

  11. Thermal analysis of a six-channel heat-generating blockage in an LMFBR

    SciTech Connect

    Warinner, D.K.; Chao, D.H.Y.

    1980-01-01

    This paper presents a case study of the temperature fields within and around a six-channel blockage designed as a molten-fuel-release initiator in SLSF-P4, an in-reactor experiment (37-mixed-oxide pin bundle) planned for February, 1981, irradiation. To meet the experiment objectives, a minimum of ten grams of molten UO/sub 2/ must be ejected into the sodium stream from one, two, or three such blockages. The temperature fields of the electrodeposited-nickel blockage filled with a mixture of UO/sub 2/ powder, stainless steel, and gas are found at intervals of full power. The SS content, type of gas, and porosity were parameters varied in this study which used the computer codes THYME-B, SABRE-1, and ANL's version of THTB. State-of-the-art treatments of the conductivity of the mixture and the gas-gap conductance are included. The contrived-blockage design has been found to maintain structural integrity until sufficient molten fuel exists to release, challenge the subassembly, and be detected by delayed-neutron and fission-product monitors. This will serve to resolve lingering questions on rapid pin-to-pin propagation, blockage propagation, and other local-fault issues.

  12. Model-Based Systems

    NASA Technical Reports Server (NTRS)

    Frisch, Harold P.

    2007-01-01

    Engineers, who design systems using text specification documents, focus their work upon the completed system to meet Performance, time and budget goals. Consistency and integrity is difficult to maintain within text documents for a single complex system and more difficult to maintain as several systems are combined into higher-level systems, are maintained over decades, and evolve technically and in performance through updates. This system design approach frequently results in major changes during the system integration and test phase, and in time and budget overruns. Engineers who build system specification documents within a model-based systems environment go a step further and aggregate all of the data. They interrelate all of the data to insure consistency and integrity. After the model is constructed, the various system specification documents are prepared, all from the same database. The consistency and integrity of the model is assured, therefore the consistency and integrity of the various specification documents is insured. This article attempts to define model-based systems relative to such an environment. The intent is to expose the complexity of the enabling problem by outlining what is needed, why it is needed and how needs are being addressed by international standards writing teams.

  13. Hydroacoustic quantification of free-gas venting offshore Svalbard, Arctic: Changes in space and time

    NASA Astrophysics Data System (ADS)

    Greinert, J.; Veloso, M.; De Batist, M. A.; Mienert, J.

    2013-12-01

    Hydroacoustic data from a seep site area offshore Spitsbergen have been collected since 2009 by RV Helmer Hanssen (U. Tromsoe) in order to monitor the dynamics of gas bubble seepage and evaluate the amount of CH4 released at the seafloor. A large number of acoustic flares have been detected during four years of data acquisition at an intensely seeping area close to the shelf edge in 240m water depth and further down-slope between 330 and 450m water depth covering the top of the gas hydrate stability zone. Water column data were collected with an EK60 split-beam echosounder system. Seep positions were determined by accounting for motion and using split-beam information to determine the ';flare spine' for seep location as accurately as possible. The inverse hydroacoustic method for flux estimation developed by Muyakshin et al. (2010) has been adapted to be used with the angle information derived from split-beam data and using gridding algorithms for generating acoustic maps for each of the four surveys. The method evaluates the flux using the backscattering volume strength (SV) above the seafloor produced by free gas release, a bubble size distribution (BSD) function obtained from video footage and models for bubble rising speed (BRS) taken from the literature. Methane flux calculations depending on these input parameters vary from 187 T/yr to 250 T/yr assuming a continuous discharge for the 240m deep shelf-edge site, when all data sets are merged. Compared to other fluxes e.g. from specific seep areas in the Black Sea (683 T/yr Greinert et al., 2010 JGR; 1376 T/yr Römer et al., 2012 MarGeo) or the Håkon Mosby mud volcano (181 T/yr Sauter et al., 2006 EPSL) the fluxes from offshore Svalbard are similar in range but on the lower end. However, studying the ';common area' which was insonified during all four years reveals a decreasing flux of about 20% although the actual seep positions have been very persistent. The reason for this is currently unknown. The

  14. Multi-scale Hydroacoustic Remote Sensing of Sturgeon and Their Habitats in A Large, Turbid River

    NASA Astrophysics Data System (ADS)

    Jacobson, R. B.; Delonay, A.; Vishy, C.; Elliott, C. M.; Reuter, J. M.; Chojnacki, K. A.

    2009-12-01

    Restoration and management of the Lower Missouri River (LMOR) to support recovery of the endangered pallid sturgeon (Scaphirhynchus albus) requires quantifying habitats used during all life stages in order to isolate specific habitats (if any) that present bottlenecks to reproduction and survival. All life stages of the pallid sturgeon take place in deep, turbid rivers where direct observation of habitat selection, movement, and behavior are impossible. Female pallid sturgeon reproduce only once every 3-5 years, but during a reproductive season they may migrate 10’s to 100’s of kilometers to spawn in patches of only several 100’s of square meters over a period of several hours. The broad ranges of spatial and temporal scales involved in understanding how particular life stages relate to their environment, as well as the technical challenges of working in a large river, dictate application of a multi-scale, remote-sensing approach. At the scale of the entire LMOR (1300 km), extensive hydroacoustic mapping using single-beam bathymetry, acoustic Doppler current profiling (ADCP), and substrate classification has been used to quantify the fundamental biophysical capacity of river segments in terms of frequency distributions of hydraulic variables. Coordinated telemetric tracking of reproductive fish provides an understanding of home range and habitat selection at reach to segment scales, over timeframes commensurate with 3-5 year reproductive cycles. Intensive reach-scale hydroacoustic mapping using multibeam bathymetry, ADCP, and high-resolution sidescan sonar, combined with intensive telemetric tracking, provide coincident measures of habitat availability and selection for upstream-migrating and spawning fish during reproductive seasons. These assessments measure habitat variables at sub-meter to bedform scales, commensurate with the scale at which fish occupy their habitat. For example, dual-frequency identification sonar (DIDSON) imagery indicates that during

  15. Re-establishment of the IMS Hydroacoustic Station HA03, Robinson Crusoe Island, Chile

    NASA Astrophysics Data System (ADS)

    Haralabus, Georgios; Stanley, Jerry; Zampolli, Mario; Pautet, Lucie

    2015-04-01

    Water column hydrophone stations of the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) International Monitoring System (IMS) comprise typically two triplets of moored hydrophones deployed on both sides of an island. Triplet distances vary approximately between 50 - 200 km from the island, with each triplet connected to the receiving shore equipment by fibre-optic submarine data cables. Once deployed, the systems relay underwater acoustic waveforms in the band 1 - 100 Hz in real time to Vienna via a shore based satellite link. The design life of hydroacoustic (HA) stations is at least 20 years, without need for any maintenance of the underwater system (UWS). The re-establishment of hydrophone station HA03 at Robinson Crusoe Island (670 km West of the Chilean mainland) is presented here. The station was destroyed in February 2010 by a Tsunami induced by an 8.8 magnitude earthquake. After a major engineering and logistical undertaking HA03 is now back in operation since April 2014. The main phases of the project are presented: (i) the installation of a shore facility for the reception of the hydrophone data from the UWS, which also relays the data back to the CTBTO International Data Center (IDC) in Vienna via a real-time satellite connection, (ii) the manufacturing and testing of the system to meet the stringent requirements of the Nuclear-Test-Ban Treaty, and (iii) the installation of the UWS with a state-of-the-art cable ship. Examples of data acquired by HA03 are also presented. These include hydroacoustic signals from the 1 April 2014 magnitude 8.2 earthquake in Northern Chile, bursting underwater bubbles from a submarine volcano near the Mariana Islands (15,000 Km away from the station), and vocalizations from the numerous marine mammals which transit in the vicinity of HA03. The use of CTBTO data for scientific purposes is possible via the virtual Data Exploitation Centre (vDEC), which is a platform that enables registered researchers to access

  16. Erlang B/C Link Availability/Blockage for Data and Voice over VDL Mode 3

    NASA Technical Reports Server (NTRS)

    Shamma, Mohammed A.

    2004-01-01

    This study looks into the blockage and availability of Digital VHF Mode 3 link. Using future predicted voice and CPDLC data traffic loads, the Erlang B and Erlang C formulas were utilized to measure the availability/blockage of the two applications over VDL mode 3. The results here, along with previous cell capacity calculations on the number of frequency channels available done as a part of a separate study, can give a measure of the overall system capacity. This study shows sufficient availability (for acceptable blockage levels for worst case traffic loads. It is found that overall the voice communications will reduce the system availability the most, followed by Management accessing portion of the data which turns limits the CPDLC capability.

  17. Estimation of tunnel blockage from wall pressure signatures: A review and data correlation

    NASA Technical Reports Server (NTRS)

    Hackett, J. E.; Wilsden, D. J.; Lilley, D. E.

    1979-01-01

    A method is described for estimating low speed wind tunnel blockage, including model volume, bubble separation and viscous wake effects. A tunnel-centerline, source/sink distribution is derived from measured wall pressure signatures using fast algorithms to solve the inverse problem in three dimensions. Blockage may then be computed throughout the test volume. Correlations using scaled models or tests in two tunnels were made in all cases. In many cases model reference area exceeded 10% of the tunnel cross-sectional area. Good correlations were obtained regarding model surface pressures, lift drag and pitching moment. It is shown that blockage-induced velocity variations across the test section are relatively unimportant but axial gradients should be considered when model size is determined.

  18. Ultra-long-range hydroacoustic observations of submarine volcanic activity at Monowai, Kermadec Arc

    NASA Astrophysics Data System (ADS)

    Metz, D.; Watts, A. B.; Grevemeyer, I.; Rodgers, M.; Paulatto, M.

    2016-02-01

    Monowai is an active submarine volcanic center in the Kermadec Arc, Southwest Pacific Ocean. During May 2011, it erupted over a period of 5 days, with explosive activity directly linked to the generation of seismoacoustic T phases. We show, using cross-correlation and time-difference-of-arrival techniques, that the eruption is detected as far as Ascension Island, equatorial South Atlantic Ocean, where a bottom moored hydrophone array is operated as part of the International Monitoring System of the Comprehensive Nuclear-Test-Ban Treaty Organization. Hydroacoustic phases from the volcanic center must therefore have propagated through the Sound Fixing and Ranging channel in the South Pacific and South Atlantic Oceans, a source-receiver distance of ~15,800 km. We believe this to be the furthest documented range of a naturally occurring underwater signal above 1 Hz. Our findings, which are consistent with observations at regional broadband stations and long-range, acoustic parabolic equation modeling, have implications for submarine volcano monitoring.

  19. Hydro-acoustic instabilities in compressible turbulent channel flow with porous walls

    NASA Astrophysics Data System (ADS)

    Scalo, Carlo; Rahbari, Iman

    2015-11-01

    C. Scalo, J. Bodart, and S. K. Lele, Phys. Fluids (2015) manipulated wall-bounded compressible turbulence by applying impedance boundary conditions (IBC) acoustically tuned to the characteristic time scale of the large-scale eddies. Near-wall turbulence was overhauled by hydro-acoustic instabilities - comprised of coherent spanwise Kelvin-Helmholtz rollers driven by Helmholtz-like acoustic resonance - while outer-layer turbulence was left structurally unaltered. We discuss linear modeling results of the observed flow response, supported by new high-fidelity simulations up to transonic bulk Mach numbers. For IBCs with zero reactance, corresponding to a Darcy-like formulation for porous walls, two dominant modes are identified whose Reynolds stress distributions overlap with the impermeable-wall turbulent buffer layer, directly affecting the near-wall turbulence cycle. For the range of wavenumbers investigated, the transition from subcritical to supercritical permeability does not significantly alter the structure of the unstable modes, showing that wall-permeability accentuates pre-existing, otherwise stable, modes. Implications on flow control strategies for compressible boundary layers over porous walls are discussed. School of Mechanical Engineering.

  20. Size-Based Hydroacoustic Measures of Within-Season Fish Abundance in a Boreal Freshwater Ecosystem

    PubMed Central

    Pollom, Riley A.; Rose, George A.

    2015-01-01

    Eleven sequential size-based hydroacoustic surveys conducted with a 200 kHz split-beam transducer during the summers of 2011 and 2012 were used to quantify seasonal declines in fish abundance in a boreal reservoir in Manitoba, Canada. Fish densities were sufficiently low to enable single target resolution and tracking. Target strengths converted to log2-based size-classes indicated that smaller fish were consistently more abundant than larger fish by a factor of approximately 3 for each halving of length. For all size classes, in both years, abundance (natural log) declined linearly over the summer at rates that varied from -0.067.day-1 for the smallest fish to -0.016.day-1 for the largest (R2 = 0.24–0.97). Inter-annual comparisons of size-based abundance suggested that for larger fish (>16 cm), mean winter decline rates were an order of magnitude lower (-0.001.day-1) and overall survival higher (71%) than in the main summer fishing season (mean loss rate -0.038.day-1; survival 33%). We conclude that size-based acoustic survey methods have the potential to assess within-season fish abundance dynamics, and may prove useful in long-term monitoring of productivity and hence management of boreal aquatic ecosystems. PMID:25875467

  1. Ambient seismic, hydroacoustic, and flexural gravity wave noise on a tabular iceberg

    NASA Astrophysics Data System (ADS)

    MacAyeal, Douglas R.; Wang, Yitan; Okal, Emile A.

    2015-02-01

    Cross correlation of ambient seismic noise between four seismographs on tabular iceberg C16, Ross Sea, Antarctica, reveals both the source and the propagation characteristics of signals associated with icebergs. We find that noise correlation functions computed from station data are asymmetric about zero time lag, and this indicates that noise observed on the iceberg originates primarily from a compact, localized source associated with iceberg collisions between C16 and a neighboring iceberg, B15A. We additionally find two, and possibly more, distinct phases of noise propagation. We believe that flexural gravity wave propagation dominates the low-frequency noise (>10 s period) and that hydroacoustic wave propagation in the water column between the ice and seabed appears to dominate high-frequency noise (>10 Hz). Faster seismic propagation dominates the intermediate band (2-6 Hz); however, we do not have sufficient data to characterize the wave mechanisms more precisely, e.g., by identifying distinct longitudinal and shear body waves and/or surface waves. Secular changes in the amplitude and timing of ambient noise correlations, e.g., a diurnal cycle and an apparent shift in the noise correlation of fast seismic modes between two periods of the deployment, allow us to speculate that ambient noise correlation analysis may be helpful in understanding the sources and environmental controls on iceberg-generated ocean noise as well as geometric properties (such as water column thickness) of subglacial lakes.

  2. Methods for Calibrating Basin-Wide Hydroacoustic Propagation in the Indian Ocean

    SciTech Connect

    Blackman, D; de Groot-Hedlin, C; Orcutt, J A; Harben, P H; Clarke, D B; Ramirez, A L

    2004-10-11

    This collaborative project was designed to test and compare methods for achieving full ocean basin propagation of hydroacoustic signals in the 5-100 Hz frequency band. Plans for a systematic calibration of the International Monitoring System (IMS) for nuclear testing were under consideration in 2000/2001. The results from this project provide information to guide such planning for future ocean basin calibration work. Several acoustic source types were tested during two sea-going experiments and most were successful at generating signals that propagated hundreds to thousands of km to be recorded at the Indian Ocean IMS hydrophone stations. Development and numerical modeling of imploding glass sphere sources was one component of this testing. The intent was to design a relatively simple-to-use source that is not subject to restrictions that can limit use of explosive charges, but whose signal is large enough to propagate 100-1000's km range. Analysis of IMS hydrophone data recording during the experiments was used to illustrate the extent of energy loss during signal propagation and to assess the accuracy with which the small acoustic sources could be located using methods typically employed for nuclear monitoring.

  3. Sensitivity of fish density estimates to standard analytical procedures applied to Great Lakes hydroacoustic data

    USGS Publications Warehouse

    Kocovsky, Patrick M.; Rudstam, Lars G.; Yule, Daniel L.; Warner, David M.; Schaner, Ted; Pientka, Bernie; Deller, John W.; Waterfield, Holly A.; Witzel, Larry D.; Sullivan, Patrick J.

    2013-01-01

    Standardized methods of data collection and analysis ensure quality and facilitate comparisons among systems. We evaluated the importance of three recommendations from the Standard Operating Procedure for hydroacoustics in the Laurentian Great Lakes (GLSOP) on density estimates of target species: noise subtraction; setting volume backscattering strength (Sv) thresholds from user-defined minimum target strength (TS) of interest (TS-based Sv threshold); and calculations of an index for multiple targets (Nv index) to identify and remove biased TS values. Eliminating noise had the predictable effect of decreasing density estimates in most lakes. Using the TS-based Sv threshold decreased fish densities in the middle and lower layers in the deepest lakes with abundant invertebrates (e.g., Mysis diluviana). Correcting for biased in situ TS increased measured density up to 86% in the shallower lakes, which had the highest fish densities. The current recommendations by the GLSOP significantly influence acoustic density estimates, but the degree of importance is lake dependent. Applying GLSOP recommendations, whether in the Laurentian Great Lakes or elsewhere, will improve our ability to compare results among lakes. We recommend further development of standards, including minimum TS and analytical cell size, for reducing the effect of biased in situ TS on density estimates.

  4. Hydroacoustic measurements of the behavioral response of arctic riverine fishes to seismic airguns.

    PubMed

    Jorgenson, John K; Gyselman, Eric C

    2009-09-01

    Seismic surveys for hydrocarbon exploration in the Mackenzie River involve the use of airguns. Airguns produce a repetitive, intense, low-frequency sound that has the potential to cause physiological damage and behavioral changes in fishes. Some of these impacts have been documented in marine environments but few studies have been conducted in freshwater systems where the confining nature of the environment produces a different acoustic regime and could constrain possible fish response. In the current study, hydroacoustic surveys are conducted in the presence of airgun firing in the Mackenzie River to determine if fish behavior can mitigate or enhance the potential impact of this sound. It is shown that fish behavioral characteristics measured in this study are generally not changed by the presence of airgun noise. The most likely mechanism to facilitate a severe physiological effect in fishes from a mobile airgun firing is a herding response in front of the airgun, resulting in prolonged exposure to the noise. Analysis of tracked fish directional movement does not indicate that herding behavior occurs. Consequently, no evidence is found to indicate that fishes in this study would sustain severe physiological damage from this airgun seismic survey. PMID:19739773

  5. Turbulence Intensity at Inlet of 80- by 120-Foot Wind Tunnel Caused by Upwind Blockage

    NASA Technical Reports Server (NTRS)

    Salazar, Denise; Yuricich, Jillian

    2014-01-01

    In order to estimate the magnitude of turbulence in the National Full-Scale Aerodynamics Complex (NFAC) 80- by 120-Foot Wind Tunnel (80 x 120) caused by buildings located upwind from the 80 x 120 inlet, a 150th-scale study was performed that utilized a nominal two-dimensional blockage placed ahead of the inlet. The distance of the blockage ahead of the inlet was varied. This report describes velocity measurements made in the plane of the 80 x 120 model inlet for the case of zero ambient (atmospheric) wind.

  6. Tube Support Plate Blockage Evaluation with Televisual Examination and Eddy Current Analysis

    NASA Astrophysics Data System (ADS)

    Châtellier, L.; Stindel, M.; Devinck, J. M.; Chavigny, F.; De Bouvier, O.

    2009-03-01

    In some steam generators with broached tube support plates (TSP), water-holes were observed to be clogged. This phenomenon can cause U-bend instability. The challenge is to estimate the average blockage level for each TSP in order to conduct the safety studies based on thermal-hydraulic models. This estimation is also necessary to plan maintenance operation (chemical cleaning) and follow the phenomenon after cleaning. This paper presents the technique used by EDF so as to estimate TSP blockage. The method relies on the association of visual inspection of the upper TSP and eddy current signal analysis.

  7. Ionic charge transport between blockages: Sodium cation conduction in freshly excised bulk brain tissue

    NASA Astrophysics Data System (ADS)

    Emin, David; Akhtari, Massoud; Ellingson, B. M.; Mathern, G. W.

    2015-08-01

    We analyze the transient-dc and frequency-dependent electrical conductivities between blocking electrodes. We extend this analysis to measurements of ions' transport in freshly excised bulk samples of human brain tissue whose complex cellular structure produces blockages. The associated ionic charge-carrier density and diffusivity are consistent with local values for sodium cations determined non-invasively in brain tissue by MRI (NMR) and diffusion-MRI (spin-echo NMR). The characteristic separation between blockages, about 450 microns, is very much shorter than that found for sodium-doped gel proxies for brain tissue, >1 cm.

  8. Ionic charge transport between blockages: Sodium cation conduction in freshly excised bulk brain tissue

    SciTech Connect

    Emin, David; Akhtari, Massoud; Ellingson, B. M.; Mathern, G. W.

    2015-08-15

    We analyze the transient-dc and frequency-dependent electrical conductivities between blocking electrodes. We extend this analysis to measurements of ions’ transport in freshly excised bulk samples of human brain tissue whose complex cellular structure produces blockages. The associated ionic charge-carrier density and diffusivity are consistent with local values for sodium cations determined non-invasively in brain tissue by MRI (NMR) and diffusion-MRI (spin-echo NMR). The characteristic separation between blockages, about 450 microns, is very much shorter than that found for sodium-doped gel proxies for brain tissue, >1 cm.

  9. Model Based Definition

    NASA Technical Reports Server (NTRS)

    Rowe, Sidney E.

    2010-01-01

    In September 2007, the Engineering Directorate at the Marshall Space Flight Center (MSFC) created the Design System Focus Team (DSFT). MSFC was responsible for the in-house design and development of the Ares 1 Upper Stage and the Engineering Directorate was preparing to deploy a new electronic Configuration Management and Data Management System with the Design Data Management System (DDMS) based upon a Commercial Off The Shelf (COTS) Product Data Management (PDM) System. The DSFT was to establish standardized CAD practices and a new data life cycle for design data. Of special interest here, the design teams were to implement Model Based Definition (MBD) in support of the Upper Stage manufacturing contract. It is noted that this MBD does use partially dimensioned drawings for auxiliary information to the model. The design data lifecycle implemented several new release states to be used prior to formal release that allowed the models to move through a flow of progressive maturity. The DSFT identified some 17 Lessons Learned as outcomes of the standards development, pathfinder deployments and initial application to the Upper Stage design completion. Some of the high value examples are reviewed.

  10. A new source discriminant based on frequency dispersion for hydroacoustic phases recorded by T-phase stations

    NASA Astrophysics Data System (ADS)

    Talandier, Jacques; Okal, Emile A.

    2016-07-01

    In the context of the verification of the Comprehensive Nuclear-Test Ban Treaty in the marine environment, we present a new discriminant based on the empirical observation that hydroacoustic phases recorded at T-phase stations from explosive sources in the water column feature a systematic inverse dispersion, with lower frequencies traveling slower, which is absent from signals emanating from earthquake sources. This difference is present even in the case of the so-called "hotspot earthquakes" occurring inside volcanic edifices featuring steep slopes leading to efficient seismic-acoustic conversions, which can lead to misidentification of such events as explosions when using more classical duration-amplitude discriminants. We propose an algorithm for the compensation of the effect of dispersion over the hydroacoustic path based on a correction to the spectral phase of the ground velocity recorded by the T-phase station, computed individually from the dispersion observed on each record. We show that the application of a standard amplitude-duration algorithm to the resulting compensated time series satisfactorily identifies records from hotspot earthquakes as generated by dislocation sources, and present a full algorithm, lending itself to automation, for the discrimination of explosive and earthquake sources of hydroacoustic signals at T-phase stations. The only sources not readily identifiable consist of a handful of complex explosions which occurred in the 1970s, believed to involve the testing of advanced weaponry, and which should be independently identifiable through routine vetting by analysts. While we presently cannot provide a theoretical justification to the observation that only explosive sources generate dispersed T phases, we hint that this probably reflects a simpler, and more coherent distribution of acoustic energy among the various modes constituting the wavetrain, than in the case of dislocation sources embedded in the solid Earth.

  11. A new source discriminant based on frequency dispersion for hydroacoustic phases recorded by T-phase stations

    NASA Astrophysics Data System (ADS)

    Talandier, Jacques; Okal, Emile A.

    2016-09-01

    In the context of the verification of the Comprehensive Nuclear-Test Ban Treaty in the marine environment, we present a new discriminant based on the empirical observation that hydroacoustic phases recorded at T-phase stations from explosive sources in the water column feature a systematic inverse dispersion, with lower frequencies traveling slower, which is absent from signals emanating from earthquake sources. This difference is present even in the case of the so-called `hotspot earthquakes' occurring inside volcanic edifices featuring steep slopes leading to efficient seismic-acoustic conversions, which can lead to misidentification of such events as explosions when using more classical duration-amplitude discriminants. We propose an algorithm for the compensation of the effect of dispersion over the hydroacoustic path based on a correction to the spectral phase of the ground velocity recorded by the T-phase station, computed individually from the dispersion observed on each record. We show that the application of a standard amplitude-duration algorithm to the resulting compensated time-series satisfactorily identifies records from hotspot earthquakes as generated by dislocation sources, and present a full algorithm, lending itself to automation, for the discrimination of explosive and earthquake sources of hydroacoustic signals at T-phase stations. The only sources not readily identifiable consist of a handful of complex explosions which occurred in the 1970s, believed to involve the testing of advanced weaponry, and which should be independently identifiable through routine vetting by analysts. While we presently cannot provide a theoretical justification to the observation that only explosive sources generate dispersed T phases, we hint that this probably reflects a simpler, and more coherent distribution of acoustic energy among the various modes constituting the wave train, than in the case of dislocation sources embedded in the solid Earth.

  12. Analysis of particulate contamination in ampoules using a light blockage particle analyser.

    PubMed

    Alexander, D M; Veltman, A M

    1985-01-01

    A method of opening ampoules without introducing particles has been developed and the level of particulate contamination in a number of ampoule solutions using a light blockage particle analyser (HIAC) has been determined. Low levels of contamination were found and a method of setting limits of particulate contamination in ampoules is suggested. PMID:2858521

  13. Swirl, Expansion Ratio and Blockage Effects on Confined Turbulent Flow. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Scharrer, G. L.

    1982-01-01

    A confined jet test facility, a swirles, flow visualization equipment, five-hole pitot probe instrumentation; flow visualization; and effects of swirl on open-ended flows, of gradual expansion on open-ended flows, and blockages of flows are addressed.

  14. Structural Blockage: A Cross-national Study of Economic Dependency, State Efficacy, and Underdevelopment.

    ERIC Educational Resources Information Center

    Delacroix, Jacques; Ragin, Charles C.

    1981-01-01

    Presents a statistical analysis of dependency of developing nations on more highly developed and industrialized nations and relates this dependency to various degrees of economic development. The analysis is based on the structural blockage argument (one of several dependency arguments contained in many versions of dependency theory). Emphasizes…

  15. Physical therapy and anesthetic blockage for treating temporomandibular disorders: A clinical trial

    PubMed Central

    Nascimento, Mirella M.; Porto, Gabriela G.; Ferdinanda, Greiciane; Nogueira, Cyntia M.; Raimundo, Ronaldo C.

    2013-01-01

    Purpose: the aim of this study was to evaluate the use of physical therapy and anesthetic blockage of the auriculotemporal nerve as a treatment for temporomandibular joint disorders. Methods: the sample comprised of twenty patients with a diagnosis of disc displacement with/ without reduction and arthralgia according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD Axis I Group IIa, IIb and IIIa). Ten patients (group 1) underwent a cycle of eight anesthetic blockages of the auriculotemporal nerve with injections (1 per week) of 1 ml of bupivacaine 0.5% without vasoconstrictor for 8 weeks. The other 10 patients (group 2) received anesthetic blockage and physical therapy (massage and muscular stretching exercises). After the end of treatment all patients were evaluated at baseline, 1st week, 4th week and 2 months. The t-Student and F (ANOVA) tests were used for statistical analysis, with a significance rate of 5%. Results: there was a significant difference when both groups were compared according to VAS score (p=0.027). There was no significant difference for the other variables: MMO and jaw protrusion. Conclusion: the anesthetic blockage and physical therapy, when used together, are effective in the reduction of pain in patients with TMD. Key words:Temporomandibular joint disorders, physical therapy, physiotherapy and nerve block, local anesthetic, bupivacaine. PMID:23229236

  16. Modeling the conversion of hydroacoustic to seismic energy at island and continental margins: preliminary analysis of Ascension Island data

    SciTech Connect

    Harben, P.; Rodgers, A.

    1999-07-26

    Seismic stations at islands and continental margins will be an essential component of the International Monitoring System (IMS) for event location and identification in support of Comprehensive Nuclear-Test-Ban Treaty (CTBT) monitoring. Particularly important will be the detection and analysis of hydroacoustic-to-seismic converted waves (T-phases) at island or continental margins. Acoustic waves generated by sources in or near the ocean propagate for long distances very efficiently due to the ocean sound speed channel (SOFAR) and low attenuation. When ocean propagating acoustic waves strike an island or continental margin they are converted to seismic (elastic) waves. We are using a finite difference code to model the conversion of hydroacoustic T-waves at an island or continental margin. Although ray-based methods are far more efficient for modeling long-range (> 1000 km) high-frequency hydroacoustic propagation, the finite difference method has the advantage of being able to model both acoustic and elastic wave propagation for a broad range of frequencies. The method allows us to perform simulations of T-phases to relatively high frequencies ({>=}10 Hz). Of particular interest is to identify factors that affect the efficiency of T-phase conversion, such as the topographic slope and roughness at the conversion point and elastic velocity structure within the island or continent. Previous studies have shown that efficient T-phase conversion occurs when the topographic slope at the conversion point is steep (Cansi and Bethoux, 1985; Talandier and Okal, 1998). Another factor impacting T-phase conversion may be the near-shore structure of the sound channel. It is well known that the depth to the sound channel axis decreases in shallow waters. This can weaken the channeled hydroacoustic wave. Elastic velocity structure within the island or continent will impact how the converted seismic wave is refracted to recording stations at the surface and thus impact the T

  17. Optimization of Concurrent Deployments of the Juvenile Salmon Acoustic Telemetry System and Other Hydroacoustic Equipment at John Day Dam

    SciTech Connect

    Ploskey, Gene R.; Hughes, James S.; Khan, Fenton; Kim, Jina; Lamarche, Brian L.; Johnson, Gary E.; Choi, Eric Y.; Faber, Derrek M.; Wilberding, Matthew C.; Deng, Zhiqun; Weiland, Mark A.; Zimmerman, Shon A.; Fischer, Eric S.; Cushing, Aaron W.

    2008-09-01

    The purpose of this report is to document the results of the acoustic optimization study conducted at John Day Dam during January and February 2008. The goal of the study was to optimize performance of the Juvenile Salmon Acoustic Telemetry System (JSATS) by determining deployment and data acquisition methods to minimize electrical and acoustic interference from various other acoustic sampling devices. Thereby, this would allow concurrent sampling by active and passive acoustic methods during the formal evaluations of the prototype surface flow outlets at the dam during spring and summer outmigration seasons for juvenile salmonids. The objectives for the optimization study at John Day Dam were to: 1. Design and test prototypes and provide a total needs list of pipes and trolleys to deploy JSATS hydrophones on the forebay face of the powerhouse and spillway. 2. Assess the effect on mean percentage decoded of JSATS transmissions from tags arrayed in the forebay and detected on the hydrophones by comparing: turbine unit OFF vs. ON; spill bay OPEN vs. CLOSED; dual frequency identification sonar (DIDSON) and acoustic Doppler current profiler (ADCP) both OFF vs. ON at a spill bay; and, fixed-aspect hydroacoustic system OFF vs. ON at a turbine unit and a spill bay. 3. Determine the relationship between fixed-aspect hydroacoustic transmit level and mean percentage of JSATS transmissions decoded. The general approach was to use hydrophones to listen for transmissions from JSATS tags deployed in vertical arrays in a series perpendicular to the face of the dam. We used acoustic telemetry equipment manufactured by Technologic and Sonic Concepts. In addition, we assessed old and new JSATS signal detectors and decoders and two different types of hydrophone baffling. The optimization study consisted of a suite of off/on tests. The primary response variable was mean percentage of tag transmissions decoded. We found that there was no appreciable adverse effect on mean percentage

  18. Hydroacoustic Evaluation of Juvenile Salmonid Passage at The Dalles Dam Sluiceway, 2005

    SciTech Connect

    Johnson, Gary E.; Khan, Fenton; Hedgepeth, J; Mueller, Robert P.; Rakowski, Cynthia L.; Richmond, Marshall C.; Serkowski, John A.; Skalski, John R.

    2006-06-01

    The U.S. Army Corps of Engineers Portland District engaged the Pacific Northwest National Laboratory to evaluate fish passage at The Dalles Dam powerhouse in 2005. The goal of the study was to provide information on smolt passage that will inform decisions on long-term measures and operations to enhance sluiceway passage and reduce turbine passage to improve smolt survival at the dam. The study addressed one of the main programs dedicated to improving juvenile salmonid survival at The Dalles Dam: Surface Flow Bypass. The study objectives (see below) were met using a combination of hydroacoustic and hydraulic data. The study incorporated fixed-location hydroacoustic methods across the entire powerhouse, with especially intense sampling using multiple split-beam transducers at all sluiceway portals. We did not sample fish passage at the spillway in 2005. In the sluiceway nearfield, we used an acoustic camera to track fish movements. The fish data were interpreted with hydraulic data from a computational fluid dynamics (CFD) model. Fish passage data were collected in the framework of an “experiment” using a randomized block design (3-day treatments; two treatments) to compare two sluiceway operational configurations: Sluice 2+5 and Sluice 2+19 (six gates open for each configuration). Total project outflow was 76% of the 10-year average for spring and 71% of the 10-year average for summer. Based on these findings, we make the following recommendations: 1) The sluice should be operated 24 h/d from April until November. 2) Open six rather than three sluice gates to take advantage of the maximum hydraulic capacity of the sluiceway. 3) Open the three gates above the western-most operating main turbine unit and the three gates at MU 8 where turbine passage rates are relatively high. 4) Operate the turbine units below open sluice gates as a standard fish operations procedure. 5) Develop hydraulic and entrance enhancements to the sluiceway to tap the potential of The

  19. Measuring real-time streamflow using emerging technologies: Radar, hydroacoustics, and the probability concept

    USGS Publications Warehouse

    Fulton, J.; Ostrowski, J.

    2008-01-01

    Forecasting streamflow during extreme hydrologic events such as floods can be problematic. This is particularly true when flow is unsteady, and river forecasts rely on models that require uniform-flow rating curves to route water from one forecast point to another. As a result, alternative methods for measuring streamflow are needed to properly route flood waves and account for inertial and pressure forces in natural channels dominated by nonuniform-flow conditions such as mild water surface slopes, backwater, tributary inflows, and reservoir operations. The objective of the demonstration was to use emerging technologies to measure instantaneous streamflow in open channels at two existing US Geological Survey streamflow-gaging stations in Pennsylvania. Surface-water and instream-point velocities were measured using hand-held radar and hydroacoustics. Streamflow was computed using the probability concept, which requires velocity data from a single vertical containing the maximum instream velocity. The percent difference in streamflow at the Susquehanna River at Bloomsburg, PA ranged from 0% to 8% with an average difference of 4% and standard deviation of 8.81 m3/s. The percent difference in streamflow at Chartiers Creek at Carnegie, PA ranged from 0% to 11% with an average difference of 5% and standard deviation of 0.28 m3/s. New generation equipment is being tested and developed to advance the use of radar-derived surface-water velocity and instantaneous streamflow to facilitate the collection and transmission of real-time streamflow that can be used to parameterize hydraulic routing models.

  20. Hydroacoustic Monitoring of Downstream Migrant Salmon and Steelhead at Wells Dam in Spring 1984.

    SciTech Connect

    Raemhild, Gary A.

    1984-10-31

    The downstream migration of salmon and steelhead in spring 1984 at Wells Dam on the mid-Columbia River was monitored using hydroacoustics. The primary objective of this research was to document run timing and describe the distribution of smolts at the dam. The study occurred from April 2 to June 15, 1984. Four transducers were deployed at the bases of pier noses at Turbines 3, 5, 7, and 9 and aimed up 24/sup 0/ into the forebay. They were sampled once every hour, 24 hours per day, for 75 days. An index of fish passage was reported daily to the Water Budget Center in Portland, Oregon. This index was computed as follows. For each 24-h period, separate fish passage rates (number/time) at each of the four sampling locations were estimated by dividing the sum of the ''weighted'' fish detections by total sample time. These four values then were averaged to produced the daily index (number/day/location). The first substantial increase in fish passage occurred on April 25, 1984 due to the chinook released from the Winthrop hatchery on April 23. During May, run timing was fairly uniform except for peaks on May 2, 14, 18, and 22. The unexpected peak in run size that occurred from May 29 to June 2 could have been caused by juvenile mountain whitefish. Although the proportion of each species varied, chinook passage probably peaked in late April, and steelhead in the first two weeks of May; sockeye passage was variable throughout the study. The data indicated that most downstream migrants were distributed high in the water column and toward the western end of the dam. Average hourly passage rates for day and night were similar, but more fish passed the dam during the longer period of daylight than the shorter period of darkness. 7 refs., 13 figs.

  1. Bacteriophage Can Prevent Encrustation and Blockage of Urinary Catheters by Proteus mirabilis.

    PubMed

    Nzakizwanayo, Jonathan; Hanin, Aurélie; Alves, Diana R; McCutcheon, Benjamin; Dedi, Cinzia; Salvage, Jonathan; Knox, Karen; Stewart, Bruce; Metcalfe, Anthony; Clark, Jason; Gilmore, Brendan F; Gahan, Cormac G M; Jenkins, A Toby A; Jones, Brian V

    2015-01-01

    Proteus mirabilis forms dense crystalline biofilms on catheter surfaces that occlude urine flow, leading to serious clinical complications in long-term catheterized patients, but there are presently no truly effective approaches to control catheter blockage by this organism. This study evaluated the potential for bacteriophage therapy to control P. mirabilis infection and prevent catheter blockage. Representative in vitro models of the catheterized urinary tract, simulating a complete closed drainage system as used in clinical practice, were employed to evaluate the performance of phage therapy in preventing blockage. Models mimicking either an established infection or early colonization of the catheterized urinary tract were treated with a single dose of a 3-phage cocktail, and the impact on time taken for catheters to block, as well as levels of crystalline biofilm formation, was measured. In models of established infection, phage treatment significantly increased time taken for catheters to block (∼3-fold) compared to untreated controls. However, in models simulating early-stage infection, phage treatment eradicated P. mirabilis and prevented blockage entirely. Analysis of catheters from models of established infection 10 h after phage application demonstrated that phage significantly reduced crystalline biofilm formation but did not significantly reduce the level of planktonic cells in the residual bladder urine. Taken together, these results show that bacteriophage constitute a promising strategy for the prevention of catheter blockage but that methods to deliver phage in sufficient numbers and within a key therapeutic window (early infection) will also be important to the successful application of phage to this problem. PMID:26711744

  2. Principles of models based engineering

    SciTech Connect

    Dolin, R.M.; Hefele, J.

    1996-11-01

    This report describes a Models Based Engineering (MBE) philosophy and implementation strategy that has been developed at Los Alamos National Laboratory`s Center for Advanced Engineering Technology. A major theme in this discussion is that models based engineering is an information management technology enabling the development of information driven engineering. Unlike other information management technologies, models based engineering encompasses the breadth of engineering information, from design intent through product definition to consumer application.

  3. The effects of ground water, slope stability, and seismic hazards on the stability of the South Fork Castle Creek blockage in the Mount St. Helens area, Washington

    USGS Publications Warehouse

    Meyer, William; Sabol, M.A.; Glicken, H.X.; Voight, Barry

    1985-01-01

    A slope stability analysis on the South Fork Castle Creek debris avalanche blockage, near Mount St. Helens, Washington, was conducted to determine the likelihood of mass failure of the blockage and resultant breakout of South Fork Castle Creek Lake. On the basis of material properties, groundwater levels, and seismic history of the blockage, slope stability with and without earthquake-induced forces was determined. Results indicated that the blockage will not fail from gravitational forces at September 1983 groundwater levels. An increase of 25 feet or more in water levels could cause local failures, but massive failure of the blockage is improbable. Blockage slopes are potentially unstable for present and higher water levels if an earthquake with magnitude greater than 6.0 should occur. Retrogressive slope failures are possible, but lowering of the blockage crest below lake level and consequent lake breakout are considered remote. Significant earthquake shaking could cause cracks in the blockage that might facilitate piping. (USGS)

  4. Overview of hydro-acoustic current-measurement applications by the U.S. geological survey in Indiana

    USGS Publications Warehouse

    Morlock, Scott E.; Stewart, James A.

    1999-01-01

    The U.S. Geological Survey (USGS) maintains a network of 170 streamflow-gaging stations in Indiana to collect data from which continuous records of river discharges are produced. Traditionally, the discharge record from a station is produced by recording river stage and making periodic discharge measurements through a range of stage, then developing a relation between stage and discharge. Techniques that promise to increase data collection accuracy and efficiency include the use of hydro-acoustic instrumentation to measure river velocities. The velocity measurements are used to compute river discharge. In-situ applications of hydro-acoustic instruments by the USGS in Indiana include acoustic velocity meters (AVM's) at six streamflow-gaging stations and newly developed Doppler velocity meters (DVM's) at two stations. AVM's use reciprocal travel times of acoustic signals to measure average water velocities along acoustic paths, whereas DVM's use the Doppler shift of backscattered acoustic signals to compute water velocities. In addition to the in-situ applications, three acoustic Doppler current profilers (ADCP's) are used to make river-discharge measurements from moving boats at streamflow-gaging stations in Indiana. The USGS has designed and is testing an innovative unmanned platform from which to make ADCP discharge measurements.

  5. Using the geodetic and hydroacoustic measurements to investigate the bathymetric and morphometric parameters of Lake Hancza (Poland)

    NASA Astrophysics Data System (ADS)

    Popielarczyk, Dariusz; Templin, Tomasz; Łopata, Michał

    2015-12-01

    Most of the inland lakes do not have up-to-date bathymetry. However, a significant progress in surveying technologies creates a possibility to quickly and accurately describe the underwater environment. Modern geodetic and global positioning techniques integrated with hydroacoustic systems provide a great opportunity to study the bottom shape with high resolution. Our study presents a reliable methodology for investigation of bathymetry and morphometric parameters with the use of GNSS positioning techniques and single beam echosounder. The research was implemented on the deepest, glacial reservoir in the central part of European Depression - Lake Hancza. Direct hydroacoustic and geodetic measurements completed by sediment study were conducted by the authors in 2010-2013. After performing a field survey the Digital Elevation Model was constructed and the new bathymetric map and morphometric card were elaborated. The maximum depth was confirmed to be 105.55 m. The final conclusions show that the available bathymetric data and morphometric parameters of lakes are highly dependent on the research methodology used, the precision and accuracy of measurement techniques, proper water level determination, digital elevation model and bathymetric map elaboration processes.

  6. Passive probing of the sound fixing and ranging channel with hydro-acoustic observations from ridge earthquakes.

    PubMed

    Evers, Läslo G; Snellen, Mirjam

    2015-04-01

    The International Monitoring System includes a hydro-acoustic part to verify the Comprehensive Nuclear-Test-Ban Treaty. Besides explosive signals, monitoring stations also detect acoustic waves from earthquakes that travel through the SOund Fixing And Ranging (SOFAR) channel. The travel times of such detections are listed in the Reviewed Event Bulletin, which is statistically evaluated for the stations located in the Pacific, Indian, and Atlantic Oceans. The celerities of ridge earthquakes are calculated to build up a homogeneous data-set, based on similar source mechanisms. The celerity is defined as the epicentral distance divided by the travel time. The global characteristics of these celerities can be well understood in terms of temperature variations in the SOFAR channel. A detailed velocity profile has been retrieved for the Atlantic Ocean where large differences (14 m/s) are found between the southern and northern parts of the basin. Propagation modeling with normal modes supports these findings, which shows that the celerity gives an estimate of the sound speed in the SOFAR channel. These results compare remarkably well with those from active experiments, showing the ability of passively probing the SOFAR channel with hydro-acoustic waves from earthquake sources. PMID:25920862

  7. Effects of the Antarctic Circumpolar Current on hydroacoustic propagation and implications for Nuclear Explosion Monitoring

    NASA Astrophysics Data System (ADS)

    de Groot-Hedlin, C. D.; Blackman, D. K.; Jenkins, C. S.

    2008-12-01

    A series of small depth charges was detonated along a transect from New Zealand to Antarctica over a period of three days in late December of 2006. The hydroacoustic signals were recorded by a hydrophone deployed near the source, and at a sparse network of permanent hydrophone stations operated by the International Monitoring System (IMS), at distances up to 9600 km. Our purpose was to determine how well signal characteristics could be predicted by the World Ocean Atlas 2005 (WOA05) climatological database for sources within the Antarctic Circumpolar Current (ACC). Waveforms were examined in the 1-100 Hz frequency band, and it was found that, for clear transmission paths, the shot signals exceeded the noise only at frequencies above 20-30 Hz. Comparisons of signal spectra for recordings near the source and at the IMS stations show that transmission loss is nearly uniform as a function of frequency. Where recorded signal to noise ratios are high, observed and predicted travel times and signal dispersion agree to within two seconds under the assumption that propagation is adiabatic and follows a geodesic path. The deflection of the transmission path by abrupt spatial variations in sound speed at the northern ACC boundary is predicted to decrease travel times to the IMS stations by several seconds, depending on the path. Acoustic velocities within the ACC are predicted to vary monthly, hence the accuracy of source location estimates based only on arrival times at IMS stations depends on the monthly or seasonal database used to predict travel times, and on whether we account for path deflection. However, estimates of source locations within the ACC that are based only on observed waveforms at IMS hydrophones are highly dependent on the configuration of the IMS array; a set of shots observed only at an IMS station in the Indian Ocean and another in the South Pacific was located to within 10 km in longitude, but was unconstrained in latitude. Several sets of shots

  8. Hydroacoustic Evaluation of Juvenile Salmonid Passage at The Dalles Dam in 2004

    SciTech Connect

    Johnson, Gary E.; Hanks, Michael E.; Khan, Fenton; Cook, Chris B.; Hedgepeth, J; Mueller, Robert P.; Rakowski, Cynthia L.; Richmond, Marshall C.; Sargeant, Susan L.; Serkowski, John A.; Skalski, John R.

    2005-06-01

    The U.S. Army Corps of Engineers Portland District engaged the Pacific Northwest National Laboratory to evaluate juvenile salmon passage at The Dalles Dam in 2004 to inform decisions about long-term measures and operations to enhance sluiceway and spill passage and reduce turbine passage to improve smolt survival at the dam. PNNL used fixed-location hydroacoustic sampling across the entire project, especially at the sluiceway and spillway, using multiple split-beam transducers at selected locations. At the sluiceway nearfield, we used an acoustic camera to track fish. The fish data were interpreted and integrated with hydraulic data from a CFD model and in-field ADCP measurements. Two sluiceway operations were compared: West only (SL 1) vs. West+East (SL 1 + SL 18). Based on our findings, we concluded that The Dalles Dam sluiceway has the potential to be highly efficient and effective at passing juvenile salmonids. This potential could be tapped with hydraulic and entrance enhancements to the sluiceway. We recommended the following: (1) six rather than three sluice gates should be opened to take advantage of the maximum hydraulic capacity of the sluiceway. (2) The turbine units below open sluice gates should be operated as a standard fish operations procedure. (3) In 2005, the Corps and fisheries agencies should consider operating sluice gates in one or more of the following combinations of six gates: (a) SL 1-1, 1-2, 1-3 and SL 18-1, 18-2, 18-3 (repeat 2004 operation), (b) SL 1-1, 1-2, 1-3 and SL 11-1, 11-2, 11-3, or (c) SL 1-1, 1-2, 1-3 and SL 2-1, 2-2, 2-3. The following elements for surface flow bypasses which should be considered during design of any sluiceway enhancements at The Dalles Dam: (1) form an extensive surface flow bypass flow net (surface bypass discharge greater than {approx}7% of total project discharge), (2) create a gradual increase in water velocity approaching the surface flow bypass (ideally, acceleration < 1 m/s/m), (3) make water

  9. Hydroacoustic Records of the First Historical Eruption of Anatahan Volcano, Mariana Islands

    NASA Astrophysics Data System (ADS)

    Dziak, R.; Park, M.; Matsumoto, H.; Fox, C.; Byun, S.; Fowler, M.; Haxel, J.; Embley, R.

    2003-12-01

    For the past decade, NOAA/Pacific Marine Environmental Laboratory has monitored volcano-seismic activity from western Pacific island-arc volcanoes using an array of U.S. Navy hydrophones (called SOSUS) deployed at fixed locations throughout the North Pacific Ocean. SOSUS hydrophones are mounted within the SOFAR channel and record the hydroacoustic tertiary phase or T-wave of oceanic earthquakes from throughout the Pacific basin. Since acoustic T-waves obey cylindrical energy attenuation as opposed to the spherical attenuation of solid-earth seismic phases, sound channel hydrophones can detect often smaller and therefore more numerous earthquakes than land-based seismic networks. This property allowed for the detection of harmonic tremor from a submarine volcano in the Volcano Islands on hydrophones >14,000 km away in the eastern Pacific. The first historical eruption of Anatahan Volcano appears to have started (from satellite imagery) at 1730Z on 10 May, with an ash plume visible by 2232Z (BGVN, 5 May 2003). Records from a broadband seismometer deployed on nearby ( ˜6.5 km) Sarigan Island indicate earthquake activity increased at about 1300Z on 10 May (D. Weins, pers com). SOSUS hydrophones in the western Pacific ( ˜4000 km distant) also recorded increased earthquake activity at 1300Z on 10 May as well as continuous, low-frequency (<10 Hz) energy (possible volcanic tremor) that began about a day before the seismicity. The earthquakes and tremor were detected on only two SOSUS hydrophones and therefore it was not possible to estimate their source location. The arrival azimuth of the signals were, however, consistent with a source in the Mariana Islands. To complement the SOSUS hydrophone array coverage in the western Pacific Ocean, an array of five autonomous hydrophones were deployed in February 2003 (sponsored by NOAA's Ocean Exploration Program) within the SOFAR channel along the active island- and back-arc of the Mariana Islands. All five hydrophones (1-110 Hz

  10. A New Method for Identification of Tributary Sediment Sources using Hydroacoustics

    NASA Astrophysics Data System (ADS)

    Wright, S. A.; Topping, D. J.; Melis, T. S.

    2005-12-01

    Identification of tributary sediment sources is important in geomorphologic studies because different tributaries within the same basin may deliver sediment with widely varying properties. In particular, tributaries may deliver sediment with very different grain-size distributions due to differences in lithology between tributary drainages. These differences have important implications for understanding the link between tributary sediment supply and main channel morphology. Hydroacoustic instrumentation has become popular in recent years for the study of sediment-transport processes in both marine and fluvial environments. Because suspended material scatters and attenuates acoustic energy, transducers designed to record the backscattered energy can be used to infer the suspended sediment concentration. The transducer records the energy received from direct backscattering from the particles, which is reduced by transmission losses that occur as the wave travels through the medium. These transmission losses are composed of: 1) geometrical spreading, 2) attenuation of energy by the fluid, and 3) attenuation of energy by the suspended particles. The backscatter and particle attenuation are functions primarily of the wave frequency, concentration of particles, and size of particles. Thus, for a known frequency and particle size, it is possible to invert the acoustic signal to determine particle concentration. Here, we present a new method that takes advantage of the relationship between particle attenuation and particle size in order to identify tributary sediment sources. The study site is on the Colorado River below Glen Canyon Dam, where a sideward-looking acoustic instrument has been bank-deployed since August 2002. Suspended-sediment samples were collected and a relationship was developed between suspended fine material (silt and clay) and particle attenuation (R2=0.98). However, substantial deviations occur from this relationship during flooding events from

  11. Using the international monitoring system of seismic, infrasound, and hydroacoustic sensors for global airburst detection

    NASA Astrophysics Data System (ADS)

    Brown, P.

    2014-07-01

    The impact of meter-sized objects with the Earth occurs every few weeks [1,2]. Most of these collisions result in airbursts, here defined as impacts where the meteoroid's initial kinetic energy is of order a small nuclear weapon (> 0.1 kilotons of TNT equivalent = 4.185×10^{11} J) and where this energy is fully deposited at high altitude in the atmosphere. Historically, the majority of these airbursts go undetected over oceans or remote land areas as dedicated fireball camera networks (eg.[ 3]) cover less than 1 % of the globe. Airbursts often produce meteorite falls and hence airburst data may yield pre-atmospheric orbits and physical properties for the impacting NEO providing context for recovered meteorite samples [4]. With the advent of more capable telescopic survey systems, pre-atmospheric detection of NEO-producing airbursts has become possible as evidenced by the impacts of 2014 AA and 2008 TC_3 [5]. Detection of ''terminal plungers'' is expected to become more common as projects such as ATLAS [6] become operational. This increases the need for instrumental data of the corresponding airburst, particularly its location and energy. Beginning in the late 1990s, a global network of seismic, infrasound, and hydroacoustic sensors has been deployed globally to provide treaty verification for a nuclear test ban. This network is the International Monitoring System (IMS) overseen by Comprehensive Nuclear Test Ban Treaty Organisation (CTBTO) [7]. The IMS is a unique global resource for detection of explosions worldwide and in recent years shock waves from many airbursts [8] have been detected by the system. Data from the IMS permits airburst location, origin time and energy to be measured. In rare cases, source heights, trajectories, and details of fragmentation may be obtained. Here the current capabilities of the IMS will be presented in the context of airburst detection and characterization. Empirical characteristics of the long-range sound produced by airbursts

  12. Hydroacoustic monitoring of sorted bedforms west of Sylt (SE North Sea) - Interannual variabilities during five years

    NASA Astrophysics Data System (ADS)

    Mielck, Finn; Hass, H. Christian

    2014-05-01

    Sorted bedforms can be found in coastal shelf seas worldwide. These spatially-grain-size-sorted bedforms with lengths of up to several kilometers are consisting of small rippled medium-to-coarse sand and can remain stable for decades. However, the knowledge about their development is still fragmentary. For this study, a shallow investigation area with water depth <15 m located west of the island of Sylt (SE North Sea, Germany) was annually surveyed with high-resolution hydroacoustic means (i.e. sidescan sonar, multibeam echo sounder, and sub-bottom profiler) within a time frame of five years. Aim was to detected short-time variances regarding the stability of the prevailing bedforms in an area which is strongly influenced by distinct tidal and wind-driven currents as well as storm surges. The measurements show sinuous stripes of rippled medium sand which are surrounded by smooth fine-sand areas. These sorted bedforms are basically linked to the morphology characterized by ridges and channels and could be identified as flow-transverse features that are maintained by ebb and flood currents of almost equal strengths. The bidirectional flow field generates sharp boundaries between the coarse- and fine-sand domains in both current directions. Further to the north, where unidirectional flow field conditions prevail, asymmetric bedforms could be detected with only one sharp boundary aligned counter to the current direction. While comparing the data sets of the different years, no significant changes regarding the morphology and distribution of the sorted bedforms were detectable. However, the boundaries to the fine-sand domains reveal small-scale variabilities. New minor bedforms and small rippled excavation marks developed and disappeared during the measure campaign. We suppose that these processes mainly occur during periodically recurring storm surges: Fine-sand layers are winnowed away and the shapes of the bedforms changes. Intensity and direction of these storms are

  13. Practical Considerations of Sludge and Blockage Detection Inside Pipes Using Guided Ultrasonic Waves

    NASA Astrophysics Data System (ADS)

    Ma, J.; Simonetti, F.; Lowe, M. J. S.

    2007-03-01

    It has been reported that in principle sludge and blockages in pipes can be detected and characterized by using ultrasonic guided waves. The work idealised the sludge to be an axisymmetrically uniform layer that is well bonded to the internal surface of the pipe wall. However, in practice, sludge layers have a very irregular shape, an asymmetrical circumferential profile and also uncertain bonding state. These practical issues complicate the testing and perhaps bring some different new features to the guided wave modes. We investigated the different effects of these issues on the characteristics of guided wave. A general assessment of the potential of using guided ultrasonic waves to detect and characterize sludge blockage in practice is given.

  14. Hydroacoustic, infrasonic and seismic monitoring of the submarine eruptive activity and sub-aerial plume generation at South Sarigan, May 2010

    NASA Astrophysics Data System (ADS)

    Green, David N.; Evers, Läslo G.; Fee, David; Matoza, Robin S.; Snellen, Mirjam; Smets, Pieter; Simons, Dick

    2013-05-01

    Explosive submarine volcanic processes are poorly understood, due to the difficulties associated with both direct observation and continuous monitoring. In this study hydroacoustic, infrasound, and seismic signals recorded during the May 2010 submarine eruption of South Sarigan seamount, Marianas Arc, are used to construct a detailed event chronology. The signals were recorded on stations of the International Monitoring System, which is a component of the verification measures for the Comprehensive Nuclear-Test-Ban Treaty. Numerical hydroacoustic and infrasound propagation modelling confirms that viable propagation paths from the source to receivers exist, and provide traveltimes allowing signals recorded on the different technologies to be associated. The eruption occurred in three stages, separated by three-hour periods of quiescence. 1) A 46 h period during which broadband impulsive hydroacoustic signals were generated in clusters lasting between 2 and 13 min. 95% of the 7602 identified events could be classified into 4 groups based on their waveform similarity. The time interval between clusters decreased steadily from 80 to 25 min during this period. 2) A five-hour period of 10 Hz hydroacoustic tremor, interspersed with large-amplitude, broadband signals. Associated infrasound signals were also recorded at this time. 3) An hour-long period of transient broadband events culminated in two large-amplitude hydroacoustic events and one broadband infrasound signal. A speculative interpretation, consistent with the data, suggests that during phase (1) transitions between endogenous dome growth and phreatomagmatic explosions occurred with the magma ascent rate accelerating throughout the period; during phase (2) continuous venting of fragmented magma occurred, and was powerful enough to breach the sea surface. During the climactic phase (3) discrete powerful explosions occurred, and sufficient seawater was vaporised to produce the contemporaneous 12 km altitude steam

  15. Effects of four inlet and outlet tip-annulus-area blockage configurations on the performance of an axial-flow fan rotor

    NASA Technical Reports Server (NTRS)

    Osborn, W. M.; Hager, R. D.

    1976-01-01

    An axial-flow fan rotor was tested with four configurations of tip-annulus-area blockage to speeds as high as 0.8 of design speed. The rotor performance with the four blockage configurations is compared with the unblocked rotor performance and with blockage configurations previously investigated. The blockage configurations enable the rotor to operate in a stable condition, to much lower flows than the unblocked rotor, with no evidence of rotating stall. The blockage configurations were effective in reducing rotor torque and weight flow but were accompanied by reductions in pressure ratio and efficiency.

  16. Single channel flow blockage accident phenomena identification and ranking table (PIRT) for the advanced Candu reactor

    SciTech Connect

    Popov, N.K.; Abdul-Razzak, A.; Snell, V.G.; Langman, V.; Sills, H.

    2004-07-01

    The Advanced Candu Reactor (ACRTM) is an evolutionary advancement of the current Candu 6{sup R} reactor, aimed at producing electrical power for a capital cost and at a unit-energy cost significantly less than that of the current reactor designs. The ACR retains the modular concept of horizontal fuel channels surrounded by a heavy water moderator, as with all Candu reactors. However, ACR uses slightly enriched uranium (SEU) fuel, compared to the natural uranium used in Candu 6. This achieves the twin goals of improved economics (e.g., via reductions in the heavy water requirements and the use of a light water coolant), as well as improved safety. This paper documents the results of Phenomena Identification and Ranking Table (PIRT) results for a very limited frequency, beyond design basis event of the ACR design. This PIRT is developed in a highly structured process of expert elicitation that is well supported by experimental data and analytical results. The single-channel flow blockage event in an ACR reactor assumes a severe flow blockage of one of the reactor fuel channels, which leads to a reduction of the flow in the affected channel, leading to fuel cladding and fuel temperature increase. The paper outlines the design characteristics of the ACR reactor that impact the PIRT process and computer code applicability. It also describes the flow blockage phenomena, lists all components and systems that have an important role during the event, discusses the PIRT process and results, and presents the finalized PIRT tables. (authors)

  17. Feasibility study of sludge and blockage detection inside pipes using guided torsional waves

    NASA Astrophysics Data System (ADS)

    Ma, J.; Lowe, M. J. S.; Simonetti, F.

    2007-08-01

    The accumulation of sludge and blockages in pipes is a problem which affects many industries. It has been previously reported that in principle sludge and blockages can be detected and even characterized by using guided ultrasonic torsional waves, based on an idealized model in which the sludge layer was simplified in terms of geometry and material properties. The work revealed that the presence of a layer inside a pipe scatters the guided wave propagating in the pipe and both the reflection and transmission of the guided wave can be used to effectively detect and characterize the layer. Accordingly, two guided wave measurement techniques have been proposed. This paper proceeds the work by taking into account more realistic sludge characteristics, including irregular axial and circumferential profiles of the sludge layer, imperfect bonding state between the sludge and the pipe and the material damping of the sludge. The influence of these issues is investigated to identify the critical factors that influence the detection and characterization capability of the two measurements. The study shows that both reflection and transmission measurements can be exploited usefully and non-intrusively to detect realistic accumulations of sludge and blockages; however, the quantification of such materials will be difficult due to their arbitrary shape and properties.

  18. Comparison of data correction methods for blockage effects in semispan wing model testing

    NASA Astrophysics Data System (ADS)

    Haque, Anwar U.; Asrar, Waqar; Omar, Ashraf A.; Sulaeman, Erwin; J. S Ali, Mohamed

    2016-03-01

    Wing alone models are usually tested in wind tunnels for aerospace applications like aircraft and hybrid buoyant aircraft. Raw data obtained from such testing is subject to different corrections such as wall interference, blockage, offset in angle of attack, dynamic pressure and free stream velocity etc. Since the flow is constrained by wind tunnel walls, therefore special emphasis is required to deliberate the limitation of correction methods for blockage correction. In the present research work, different aspects of existing correction methods are explored with the help of an example of a straight semi-span wing. Based on the results of analytical relationships of standard methods, it was found that although multiple variables are involved in the standard methods for the estimation of blockage, they are based on linearized flow theory such as source sink method and potential flow assumption etc, which have intrinsic limitations. Based on the computed and estimated experimental results, it is recommended to obtain the corrections by adding the difference in results of solid walls and far-field condition in the wind tunnel data. Computational Fluid Dynamics technique is found to be useful to determine the correction factors for a wing installed at zero spacer height/gap, with and without the tunnel wall.

  19. Influence of shear layers on the structure of shocks formed by rectangular and parabolic blockages placed in a subsonic flow-field

    NASA Astrophysics Data System (ADS)

    Cheeda, V. K.; Kumar, A.; Ramamurthi, K.

    2014-03-01

    Flow blockages are used to promote the transition of a flame to a detonation. The structure of shock waves formed with different configurations of blockages was experimentally determined for subsonic incoming flow. High speed subsonic flows could develop ahead of a turbulent flame and the interaction of such flows with blockages could lead to the formation of interacting shock waves, slipstreams, and expansion waves. A blow-down test setup was designed to study the interacting shock pattern formed with different configurations of blockages. The flow was found to accelerate to low supersonic velocities during its passage over the blockages. The shock structure downstream of the blockages was found to depend on the shape, size, and number of blockages as well as the spacing between them. While a parabolic-shaped blockage provided shocks of maximum strength, large blockage ratio values did not permit the formation of shocks. The shear layer, formed in the flow downstream of the blockages, reflected the expansion fan as shock waves and was found to be a major feature influencing the formation of the interacting structure of oblique shocks. The structure and strength of the shock waves are analyzed using hodograms. The formation of the interacting family of shock waves using different configurations of blockages and the spacings between them are discussed.

  20. Hydro-acoustic remote sensing of benthic biological communities on the shallow South East Australian continental shelf

    NASA Astrophysics Data System (ADS)

    Rattray, Alex; Ierodiaconou, Daniel; Laurenson, Laurie; Burq, Shoaib; Reston, Marcus

    2009-09-01

    Information regarding the composition and extent of benthic habitats on the South East Australian continental shelf is limited. In this habitat mapping study, multibeam echosounder (MBES) data are integrated with precisely geo-referenced video ground-truth data to quantify benthic biotic communities at Cape Nelson, Victoria, Australia. Using an automated decision tree classification approach, 5 representative biotic groups defined from video analysis were related to hydro-acoustically derived variables in the Cape Nelson survey area. Using a combination of multibeam bathymetry, backscatter and derivative products produced highest overall accuracy (87%) and kappa statistic (0.83). This study demonstrates that decision tree classifiers are capable of integrating variable data types for mapping distributions of benthic biological assemblages, which are important in maintaining biodiversity and other system services in the marine environment.

  1. Southeast Indian Ocean-Ridge Earthquake Sequences from Cross-correlation Analysis of Hydro-acoustic Data

    NASA Astrophysics Data System (ADS)

    Yun, S.; Ni, S.; Park, M.

    2006-12-01

    Earthquake sequences (location and timing of foreshocks and aftershocks) are critical for understanding dynamics of mid-ocean ridge and transform faults. Unfortunately whole sequences (including very small earthquakes) in the ocean can not be well recorded by land-based seismometers mostly because of large epicentral distances. Recent hydro-acoustic studies have demonstrated that T waves are very effective in detecting small submarine earthquakes because of little energy loss of T waves propagating in SOFAR channel. For example, a Mw6.2 (03/06/2006, Latitude -40.11, Longitude 78.49) transform earthquake occurred at the Southeastern Indian Ocean Ridge (an intermediate spreading rate ridge, 58-76 mm/year), but NEIC only reports 3 aftershocks in the first following week. We applied progressive multi-channel cross-correlation methods to hydro-acoustic data from the IMS arrays in Indian Ocean to detect the whole earthquake sequence. We also correlate waveform envelopes to accurately locate aftershocks and found consistent pattern of earthquake migration along the transform fault. In contrast to transform fault earthquake sequences at fast spreading ridge (East Pacific Rise, 142 mm/year) where foreshocks are observed, we failed to detect any foreshocks for the Mw6.2 earthquake though we found many aftershocks. The lack of foreshocks may be caused by lower spreading rate (hence lower temperature) or too small scale ridge segmentation. Still the number of aftershocks is much less than that of typical tectonic earthquake such as subduction or continental earthquakes, arguing different fault dynamics for mid ocean ridge systems, perhaps due to higher water content or presence of melt.

  2. Constraining the Rupture Length, Duration and Speed of the Great Sumatra-Andaman Earthquake Using Hydroacoustic Data

    NASA Astrophysics Data System (ADS)

    Tolstoy, M.; Bohnenstiehl, D. R.

    2005-12-01

    Hydroacoustic data from the International Monitoring System Diego Garcia South hydrophone station have been used to track the rupture of the Great Sumatra-Andaman Earthquake using the T-wave arrival. T-waves are generated by radiation of seismic energy at the crust-water interface, and they can travel great distances with relatively little loss in energy through a low-velocity waveguide known as the SOund Fixing and Ranging (SOFAR) channel. For this event the T-wave allows us to provide a relatively high-resolution picture of changes in the rupture speed and character. A single station approach allows topographic steering effects to be minimized. Results show that there were at least two large-scale phases of rupture with the first 180 seconds having an average speed of 2.8 km/s and the next 300 seconds having an average rupture speed of 2.1 km/s. Waveform amplitudes show two primary pulses of energy coincident with the two phases of rupture speed. Results also show that the full-length of the northern portion of the fault zone ruptured up to the latitude of the pole of rotation between the Burma and Indian Plates where subduction ends. Aftershock patterns mapped using the hydroacoustic data illustrate that in the first 30mins to few hours following the mainshock, aftershock numbers/size tracked the amplitude of waveform from the mainshock. T-wave data have the potential to address a number of fundamental questions of the rupture of this large event and also provide another tool for rapid assessment of the scale of a shallow submarine event and its tsunamigenic potential.

  3. Hydroacoustic Evaluation of Juvenile Salmonid Passage and Distribution at Detroit Dam, 2011

    SciTech Connect

    Khan, Fenton; Royer, Ida M.; Johnson, Gary E.; Ham, Kenneth D.

    2012-11-15

    Pacific Northwest National Laboratory evaluated juvenile salmonid passage and distribution at Detroit Dam (DET) on the North Santiam River, Oregon for the U.S. Army Corps of Engineers (USACE) to provide data to support decisions on long-term measures to enhance downstream passage at DET and others dams in USACE’s Willamette Valley Project. This study was conducted in response to regulatory requirements necessitated by the listing of Upper Willamette River Spring Chinook salmon (Oncorhynchus tshawytscha) and Upper Willamette River steelhead (O. mykiss) as threatened under the Endangered Species Act. The goal of the study was to provide information of juvenile salmonid passage and distribution at DET from February 2011 through February 2012. The results of the hydroacoustic study provide new and, in some cases, first-ever data on passage estimates, run timing, distributions, and relationships between fish passage and environmental variables at the dam. This information will inform management decisions on the design and development of surface passage and collection devices to help restore Chinook salmon populations in the North Santiam River watershed above DET. During the entire study period, an estimated total of 182,526 smolt-size fish (±4,660 fish, 95% CI) passed through turbine penstock intakes. Run timing peaked in winter and early spring months. Passage rates were highest during late fall, winter and early spring months and low during summer. Horizontal distribution for hours when both turbine units were operated simultaneously indicated Unit 2 passed almost twice as much fish as Unit 1. Diel distribution for smolt-size fish during the study period was fairly uniform, indicating fish were passing the turbines at all times of the day. A total of 5,083 smolt-size fish (± 312 fish, 95% CI) were estimated passed via the spillway when it was open between June 23 and September 27, 2011. Daily passage was low at the spillway during the June-August period, and

  4. Hydroacoustic Evaluation of Juvenile Salmonid Passage and Distribution at Lookout Point Dam, 2010

    SciTech Connect

    Khan, Fenton; Johnson, Gary E.; Royer, Ida M.; Hughes, James S.; Fischer, Eric S.; Trott, Donna M.; Ploskey, Gene R.

    2012-05-31

    Pacific Northwest National Laboratory evaluated juvenile salmonid passage and distribution at Lookout Point Dam (LOP) on the Middle Fork Willamette River for the U.S. Army Corps of Engineers, Portland District (USACE), to provide data to support decisions on long-term measures to enhance downstream passage at LOP and others dams in USACE's Willamette Valley Project. This study was conducted in response to the listing of Upper Willamette River Spring Chinook salmon (Oncorhynchus tshawytscha) and Upper Willamette River steelhead (O. mykiss) as threatened under the Endangered Species Act. We conducted a hydroacoustic evaluation of juvenile salmonid passage and distribution at LOP during February 2010 through January 2011. Findings from this 1 year of study should be applied carefully because annual variation can be expected due to variability in adult salmon escapement, egg-to-fry and fry-to-smolt survival rates, reservoir rearing and predation, dam operations, and weather. Fish passage rates for smolt-size fish (> {approx}90 mm and < 300 mm) were highest during December-January and lowest in mid-summer through early fall. Passage peaks were also evident in early spring, early summer, and late fall. During the entire study period, an estimated total of 142,463 fish {+-} 4,444 (95% confidence interval) smolt-size fish passed through turbine penstock intakes. Of this total, 84% passed during December-January. Run timing for small-size fish ({approx}65-90 mm) peaked (702 fish) on December 18. Diel periodicity of smolt-size fish showing crepuscular peaks was evident in fish passage into turbine penstock intakes. Relatively few fish passed into the Regulating Outlets (ROs) when they were open in summer (2 fish/d) and winter (8 fish/d). Overall, when the ROs were open, RO efficiency (RO passage divided by total project passage) was 0.004. In linear regression analyses, daily fish passage (turbines and ROs combined) for smolt-size fish was significantly related to project

  5. Hydro-acoustic resonance behavior in presence of a precessing vortex rope: observation of a lock-in phenomenon at part load Francis turbine operation

    NASA Astrophysics Data System (ADS)

    Favrel, A.; Landry, C.; Müller, A.; Yamamoto, K.; Avellan, F.

    2014-03-01

    Francis turbines operating at part load condition experience the development of a cavitating helical vortex rope in the draft tube cone at the runner outlet. The precession movement of this vortex rope induces local convective pressure fluctuations and a synchronous pressure pulsation acting as a forced excitation for the hydraulic system, propagating in the entire system. In the draft tube, synchronous pressure fluctuations with a frequency different to the precession frequency may also be observed in presence of cavitation. In the case of a matching between the precession frequency and the synchronous surge frequency, hydro-acoustic resonance occurs in the draft tube inducing high pressure fluctuations throughout the entire hydraulic system, causing torque and power pulsations. The risk of such resonances limits the possible extension of the Francis turbine operating range. A more precise knowledge of the phenomenon occurring at such resonance conditions and prediction capabilities of the induced pressure pulsations needs therefore to be developed. This paper proposes a detailed study of the occurrence of hydro-acoustic resonance for one particular part load operating point featuring a well-developed precessing vortex rope and corresponding to 64% of the BEP. It focuses particularly on the evolution of the local interaction between the pressure fluctuations at the precession frequency and the synchronous surge mode passing through the resonance condition. For this purpose, an experimental investigation is performed on a reduced scale model of a Francis turbine, including pressure fluctuation measurements in the draft tube and in the upstream piping system. Changing the pressure level in the draft tube, resonance occurrences are highlighted for different Froude numbers. The evolution of the hydro-acoustic response of the system suggests that a lock-in effect between the excitation frequency and the natural frequency may occur at low Froude number, inducing a hydro-acoustic

  6. Dyke leakage localization and hydraulic permeability estimation through self-potential and hydro-acoustic measurements: Self-potential 'abacus' diagram for hydraulic permeability estimation and uncertainty computation

    NASA Astrophysics Data System (ADS)

    Bolève, A.; Vandemeulebrouck, J.; Grangeon, J.

    2012-11-01

    In the present study, we propose the combination of two geophysical techniques, which we have applied to a dyke located in southeastern France that has a visible downstream flood area: the self-potential (SP) and hydro-acoustic methods. These methods are sensitive to two different types of signals: electric signals and water-soil pressure disturbances, respectively. The advantages of the SP technique lie in the high rate of data acquisition, which allows assessment of long dykes, and direct diagnosis in terms of leakage area delimitation and quantification. Coupled with punctual hydro-acoustic cartography, a leakage position can be precisely located, therefore allowing specific remediation decisions with regard to the results of the geophysical investigation. Here, the precise localization of leakage from an earth dyke has been identified using SP and hydro-acoustic signals, with the permeability of the preferential fluid flow area estimated by forward SP modeling. Moreover, we propose a general 'abacus' diagram for the estimation of hydraulic permeability of dyke leakage according to the magnitude of over water SP anomalies and the associated uncertainty.

  7. Model-based tomographic reconstruction

    DOEpatents

    Chambers, David H.; Lehman, Sean K.; Goodman, Dennis M.

    2012-06-26

    A model-based approach to estimating wall positions for a building is developed and tested using simulated data. It borrows two techniques from geophysical inversion problems, layer stripping and stacking, and combines them with a model-based estimation algorithm that minimizes the mean-square error between the predicted signal and the data. The technique is designed to process multiple looks from an ultra wideband radar array. The processed signal is time-gated and each section processed to detect the presence of a wall and estimate its position, thickness, and material parameters. The floor plan of a building is determined by moving the array around the outside of the building. In this paper we describe how the stacking and layer stripping algorithms are combined and show the results from a simple numerical example of three parallel walls.

  8. Model-based machine learning

    PubMed Central

    Bishop, Christopher M.

    2013-01-01

    Several decades of research in the field of machine learning have resulted in a multitude of different algorithms for solving a broad range of problems. To tackle a new application, a researcher typically tries to map their problem onto one of these existing methods, often influenced by their familiarity with specific algorithms and by the availability of corresponding software implementations. In this study, we describe an alternative methodology for applying machine learning, in which a bespoke solution is formulated for each new application. The solution is expressed through a compact modelling language, and the corresponding custom machine learning code is then generated automatically. This model-based approach offers several major advantages, including the opportunity to create highly tailored models for specific scenarios, as well as rapid prototyping and comparison of a range of alternative models. Furthermore, newcomers to the field of machine learning do not have to learn about the huge range of traditional methods, but instead can focus their attention on understanding a single modelling environment. In this study, we show how probabilistic graphical models, coupled with efficient inference algorithms, provide a very flexible foundation for model-based machine learning, and we outline a large-scale commercial application of this framework involving tens of millions of users. We also describe the concept of probabilistic programming as a powerful software environment for model-based machine learning, and we discuss a specific probabilistic programming language called Infer.NET, which has been widely used in practical applications. PMID:23277612

  9. Model-Based Safety Analysis

    NASA Technical Reports Server (NTRS)

    Joshi, Anjali; Heimdahl, Mats P. E.; Miller, Steven P.; Whalen, Mike W.

    2006-01-01

    System safety analysis techniques are well established and are used extensively during the design of safety-critical systems. Despite this, most of the techniques are highly subjective and dependent on the skill of the practitioner. Since these analyses are usually based on an informal system model, it is unlikely that they will be complete, consistent, and error free. In fact, the lack of precise models of the system architecture and its failure modes often forces the safety analysts to devote much of their effort to gathering architectural details about the system behavior from several sources and embedding this information in the safety artifacts such as the fault trees. This report describes Model-Based Safety Analysis, an approach in which the system and safety engineers share a common system model created using a model-based development process. By extending the system model with a fault model as well as relevant portions of the physical system to be controlled, automated support can be provided for much of the safety analysis. We believe that by using a common model for both system and safety engineering and automating parts of the safety analysis, we can both reduce the cost and improve the quality of the safety analysis. Here we present our vision of model-based safety analysis and discuss the advantages and challenges in making this approach practical.

  10. Model-based machine learning.

    PubMed

    Bishop, Christopher M

    2013-02-13

    Several decades of research in the field of machine learning have resulted in a multitude of different algorithms for solving a broad range of problems. To tackle a new application, a researcher typically tries to map their problem onto one of these existing methods, often influenced by their familiarity with specific algorithms and by the availability of corresponding software implementations. In this study, we describe an alternative methodology for applying machine learning, in which a bespoke solution is formulated for each new application. The solution is expressed through a compact modelling language, and the corresponding custom machine learning code is then generated automatically. This model-based approach offers several major advantages, including the opportunity to create highly tailored models for specific scenarios, as well as rapid prototyping and comparison of a range of alternative models. Furthermore, newcomers to the field of machine learning do not have to learn about the huge range of traditional methods, but instead can focus their attention on understanding a single modelling environment. In this study, we show how probabilistic graphical models, coupled with efficient inference algorithms, provide a very flexible foundation for model-based machine learning, and we outline a large-scale commercial application of this framework involving tens of millions of users. We also describe the concept of probabilistic programming as a powerful software environment for model-based machine learning, and we discuss a specific probabilistic programming language called Infer.NET, which has been widely used in practical applications. PMID:23277612

  11. Effects of percentage of blockage and flameholder downstream counterbores on lean combustion limits of premixed, prevaporized propane-air mixture

    NASA Technical Reports Server (NTRS)

    Fernandez, M. A. B.

    1983-01-01

    Lean combustion limits were determined for a premixed prevaporized propane air mixture with flat plate flame stabilizers. Experiments were conducted in a constant area flame tube combustor utilizing flameholders of varying percentages of blockage and downstream counterbores. Combustor inlet air velocity at ambient conditions was varied from 4 to 9 meters per second. Flameholders with a center hole and four half holes surrounding it were tested with 63, 73, and 85 percent blockage and counterbore diameters of 112 and 125 percent of the thru hole diameter, in addition to the no counterbore configuration. Improved stability was obtained by using counterbore flameholders and higher percentages of blockage. Increases in mixture velocity caused the equivalence ratio at blowout to increase in all cases.

  12. Investigation of Model Wake Blockage Effects at High Angles of Attack in Low-Speed Wind Tunnel

    NASA Astrophysics Data System (ADS)

    Shyu, Lih-Shyng; Chuang, Shu-Hao

    To improve the fidelity of measured aerodynamic characteristics at high angle of attack for modern jet fighters, this paper examines the model wake blockage effect. The wake blockage effect in a 2.2×3.1 m low-speed wind tunnel is investigated by analyzing drag and wall pressure measurements. Circular flat plates of different sizes are used to simulate a test model at high angles of attack. The present analysis results in simple formulas for corrections of model wake blockage effect. To verify the present correction formula, the NASA TP-1803 model is force-tested in the tunnel. The corrected test data agree well with the NASA TP-1803 data.

  13. Results from a 14-month hydroacoustic monitoring of the three mid-oceanic ridges in the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Royer, J.-Y.; Dziak, R. P.; Delatre, M.; Chateau, R.; Brachet, C.; Haxel, J. H.; Matsumoto, H.; Goslin, J.; Brandon, V.; Bohnenstielh, D. R.

    2009-04-01

    From October 2006 to January 2008, an hydroacoustic experiment in the Indian Ocean was carried out by the CNRS/University of Brest and NOAA/Oregon State University to monitor the low-level seismic activity associated with the three contrasting spreading ridges and deforming zones in the Indian Ocean. Three autonomous hydrophones were moored in the SOFAR channel by R/V Marion Dufresne for 14 months in the Madagascar Basin, and northeast and southwest of Amsterdam Island, complementing the two permanent hydroacoustic stations of the Comprehensive nuclear-Test-Ban Treaty Organization (CTBTO) located near Diego Garcia Island and off Cape Leeuwin. The three instruments successfully collected 14 month of continuous acoustic records. Combined with the records from the permanent stations, the array detected 1780 acoustic events consisting mostly of earthquake generated T-waves, but also of iceberg tremors from Wilkes Land, Antarctica. Within the triangle defined by the temporary array, the three ridges exhibit contrasting seismicity patterns. Along the Southeast Indian ridge (SEIR), the 272 acoustic events (vs 24 events in the NEIC catalog) occur predominantly along the transform faults ; only one ridge segment (76˚E) displays a continuous activity for 10 months. Along the Central Indian Ridge (CIR), seismicity is distributed along fracture zones and ridge segments (269 events vs 45 NEIC events), with two clusters of events near the triple junction (24-25S) and south of Marie-Celeste FZ (18.5S). Along the Southwest Indian Ridge (SWIR), the 222 events (vs 31 NEIC events) are distributed along the ridge segments with a larger number of events west of Melville FZ and a cluster at 58E. The immediate vicinity of the Rodrigues triple junction shows periods of quiescence and of intense activity. Some large earthquakes (Mb>5) near the triple junction (SEIR and CIR) seem to be preceded by several acoustic events that may be precursors. Finally, off-ridge seismicity is mostly

  14. Nonlinear Resonant Oscillations of Gas in Optimized Acoustical Resonators and the Effect of Central Blockage

    NASA Technical Reports Server (NTRS)

    Li, Xiaofan; Finkbeiner, Joshua; Raman, Ganesh; Daniels, Christopher; Steinetz, Bruce M.

    2003-01-01

    Optimizing resonator shapes for maximizing the ratio of maximum to minimum gas pressure at an end of the resonator is investigated numerically. It is well known that the resonant frequencies and the nonlinear standing waveform in an acoustical resonator strongly depend on the resonator geometry. A quasi-Newton type scheme was used to find optimized axisymmetric resonator shapes achieving the maximum pressure compression ratio with an acceleration of constant amplitude. The acoustical field was solved using a one-dimensional model, and the resonance frequency shift and hysteresis effects were obtained through an automation scheme based on continuation method. Results are presented for optimizing three types of geometry: a cone, a horn-cone and a half cosine-shape. For each type, different optimized shapes were found when starting with different initial guesses. Further, the one-dimensional model was modified to study the effect of an axisymmetric central blockage on the nonlinear standing wave.

  15. Effect of extradural blockage upon glucose and urea kinetics in surgical patients

    SciTech Connect

    Shaw, J.H.; Galler, L.; Holdaway, I.M.; Holdaway, C.M.

    1987-09-01

    We have determined the metabolic effects induced by the use of extradural blockage with 0.5 per cent bupivacaine hydrochloride in a group of surgical patients. Turnover rates of glucose and urea were determined isotopically using radioisotopes and studies were performed both in the basal state and during total parenteral nutrition. In the basal state, extradural blockade resulted in a decrease in the turnover rates of both glucose and urea. In addition, when extradural blockade was instituted while the patients were receiving total parenteral nutrition, there was also a significant fall in glucose turnover. We conclude that the use of extradural blockade is effective as a means of conserving bodily resources in surgical patients both in the basal state and during total parenteral nutrition.

  16. Nonlinear Resonant Oscillations of Gas in Optimized Acoustical Resonators and the Effect of Central Blockage

    NASA Technical Reports Server (NTRS)

    Li, Xiao-Fan; Finkbeiner, Joshua; Raman, Ganesh; Daniels, Christopher; Steinetz, Bruce M.

    2003-01-01

    Optimizing resonator shapes for maximizing the ratio of maximum to minimum gas pressure at an end of the resonator is investigated numerically. It is well known that the resonant frequencies and the nonlinear standing waveform in an acoustical resonator strongly depend on the resonator geometry. A quasi-Newton type scheme was used to find optimized axisymmetric resonator shapes achieving the maximum pressure compression ratio with an acceleration of constant amplitude. The acoustical field was solved using a one-dimensional model, and the resonance frequency shift and hysteresis effects were obtained through an automation scheme based on continuation method. Results are presented for optimizing three types of geometry: a cone, a horn-cone and a half cosine- shape. For each type, different optimized shapes were found when starting with different initial guesses. Further, the one-dimensional model was modified to study the effect of an axisymmetric central blockage on the nonlinear standing wave.

  17. The effect of blockage on power production for laterally aligned wind turbines

    NASA Astrophysics Data System (ADS)

    Meyer Forsting, A. R.; Troldborg, N.

    2015-06-01

    This paper studies the change in the individual power coefficients for a laterally aligned row of wind turbines over a single, free turbine in the context of varying inflow directions via numerical simulations. All turbines were rotating in-line with the main flow direction. The problem definition is similar to that of many wind turbine testing sites and wind farms. Hence any changes in the individual turbine power production could have implications regarding power curve validation procedures.These changes are relatively small and therefore the size of the computational domain was identified to be detrimental in avoiding any domain-inflicted blockage. Increasing the misalignment of the main flow direction with the row of turbines led to significant variations in the power production across turbines. At the largest inflow angle of 45° it varied from -1.1% to 2%. As a whole, the power production increased by about 0.5%, almost independent of the inflow direction.

  18. MoM solutions to building blockage of mobile satellite communications

    NASA Astrophysics Data System (ADS)

    Salameh, M. S. H. Al; Mahmoud, S. A.-R. T.

    2011-12-01

    This article presents a full-wave propagation model for arbitrary profile of building blockage in mobile satellite communications, by solving the electric field integral equation for induced surface currents using the method of moments. Asymptotic expressions are used to simplify the integrals. Scattered fields are then found by the radiation equations derived from Maxwell equations. The total received fields around different profiles of buildings are calculated as a function of space, elevation angle and frequency. The results agree well with measurements and other published data. Various useful parameters for designing robust and reliable communication systems like frequency response, average fade duration and coherence bandwidth are found. Performance of mobile satellite system is evaluated in terms of bit error rate of mobile satellite system in frequency non-selective, slowly fading channel.

  19. AT1 receptor is present in glioma cells; its blockage reduces the growth of rat glioma

    PubMed Central

    Rivera, E; Arrieta, O; Guevara, P; Duarte-Rojo, A; Sotelo, J

    2001-01-01

    Malignancy of neoplasms is partly dependent on angiogenesis. Angiotensin II mediates angiogenesis and transcription of growth-related factors through stimulation of the AT1 receptor (AT1R). Losartan, a drug used mostly for treatment of hypertension, binds strongly to this receptor. We found the presence of AT1 receptor on C6 glioma cells and studied the effect of Losartan on the growth and angiogenesis of C6 rat glioma; Losartan in dose of 80 mg/kg induced 79% reduction of tumoural volume with a significant decrease of vascular density, mitotic index and cell proliferation. Our results demonstrate the conspicuous presence of AT1R in malignant glial cells and a favourable therapeutic response in experimental glioma by selective blockage of the AT1 receptor. © 2001 Cancer Research Campaign  http://www.bjcancer.com PMID:11720480

  20. Investigation of very low blockage ratio boattail models in the Langley 16-foot transonic tunnel

    NASA Technical Reports Server (NTRS)

    Reubush, D. E.

    1976-01-01

    An investigation at an angle of attack of 0 deg was conducted in a 16 foot transonic tunnel at Mach numbers from 0.4 to 1.05 to determine the limits in Mach number at which valid boattail pressure drag data may be obtained with very low blockage ratio bodies. Extreme care was exercised when examining any data taken at subsonic Mach numbers very near 1.0 and lower than the supersonic Mach number at which shock reflections miss the model. Boattail pressure coefficient distributions did not indicate any error, but when integrated boattail pressure drag data was plotted as a function of Mach number, data which were in error were identified.

  1. Fault diagnosis for stator winding bar hollow strand blockage of turbogenerators based on data fusion

    NASA Astrophysics Data System (ADS)

    Wang, Xianpei; Dai, Zheng Y.; Liu, Zhenxing; Chen, Yalin

    2003-09-01

    Stator Winding Bar Hollow Strand Blockage (SWBHSB) is one of the main faults for large turbo-generators with water and hydrogen cooling system. It will lead to increasing water temperature at the bar exit which may cause hidden troubles for turbo-generator's security. According to a three-layer-structural model of data fusion, this paper presents a fault diagnosis method for turbo-generators based on data fusion technology. Firstly, a bp network on pixel level fusion is set up, in which several temperature parameters at the bar exit are accurately computed. Then in feature level fusion, the fingerprints are distilled from the result of pixel level fusion. Finally, decision level fusion gives a fault diagnosis for the measuring channels and thermometric components. This method can effectively avoid problems such as misinformation and fake report.

  2. Hydroacoustic Assessment of Downstream Migrating Salmonids at the Dalles Dam in Spring and Summer, 1985 Final Report.

    SciTech Connect

    Steig, Tracy W.; Johnson, Ward R.

    1986-02-15

    A hydroacoustic study of downstream migrating salmon and steelhead was conducted at The Dalles Dam. The primary objective was to estimate the effectiveness of the spillway and sluiceway in passing downstream migrants. The secondary goals were to provide information on the horizontal, vertical, and temporal distributions of downstream migrants. June 1, and the summer season was from July 1 to August 15, 1985. Nineteen transducers were deployed to monitor turbine, spillway, and sluiceway locations. The 10 h instantaneous spill effectiveness results showed that spill passed fish more efficiently during the summer study than during the spring study. During the period May 1-31 when the turbines, spillway, and sluiceway were all operating consistently, the sluiceway was found to be the most efficient method of passing fish on a percent flow basis. During the summer study, after the termination of spill, the sluiceway and turbines passed almost equal percentages of fish. The run timing during the spring showed steadily increasing numbers of fish until the peak of the run on May 16. Another, smaller peak occurred on May 20. Thereafter, passage gradually decreased through the end of the spring study. The spring run consisted of yearling chinook, steelhead and sockeye juvenile salmonids. During the summer study, fish passage gradually decreased, except for minor peaks near the beginning of the study. The summer migration consisted primarily of subyearling chinook juvenile salmonids.

  3. The pepper's natural ingredient capsaicin induces autophagy blockage in prostate cancer cells

    PubMed Central

    Ramos-Torres, Ágata; Bort, Alicia; Morell, Cecilia; Rodríguez-Henche, Nieves; Díaz-Laviada, Inés

    2016-01-01

    Capsaicin, the pungent ingredient of red hot chili peepers, has been shown to have anti-cancer activities in several cancer cells, including prostate cancer. Several molecular mechanisms have been proposed on its chemopreventive action, including ceramide accumulation, endoplasmic reticulum stress induction and NFκB inhibition. However, the precise mechanisms by which capsaicin exerts its anti-proliferative effect in prostate cancer cells remain questionable. Herein, we have tested the involvement of autophagy on the capsaicin mechanism of action on prostate cancer LNCaP and PC-3 cells. The results showed that capsaicin induced prostate cancer cell death in a time- and concentration-dependent manner, increased the levels of microtubule-associated protein light chain 3-II (LC3-II, a marker of autophagy) and the accumulation of the cargo protein p62 suggesting an autophagy blockage. Moreover, confocal microscopy revealed that capsaicin treatment increased lysosomes which co-localized with LC3 positive vesicles in a similar extent to that produced by the lysosomal protease inhibitors E64 and pepstatin pointing to an autophagolysosomes breakdown inhibition. Furthermore, we found that capsaicin triggered ROS generation in cells, while the levels of ROS decreased with N-acetyl-cysteine (NAC), a ROS scavenger. Co-treatment of cells with NAC and capsaicin abrogated the effects of capsaicin on autophagy and cell death. Normal prostate PNT2 and RWPE-1 cells were more resistant to capsaicin-induced cytotoxicity and did not accumulate p62 protein. Taken together, these results suggest that ROS-mediated capsaicin-induced autophagy blockage contributes to antiproliferation in prostate cancer cells, which provides new insights into the anticancer molecular mechanism of capsaicin. PMID:26625315

  4. Mudflow hazards along the Toutle and Cowlitz Rivers from a hypothetical failure of Spirit Lake blockage

    USGS Publications Warehouse

    Swift, C.H.; Kresch, D.L.

    1983-01-01

    The debris avalanche accompanying the May 18, 1980, eruption of Mount St. Helens, in southwestern Washington, buried the former outlet of Spirit Lake, located 5 miles north of the volcano, to a depth ranging to 500 feet. Since that time, Spirit Lake has had no natural outlet and its lake level and contents have increased significantly. Erosion at the crest of the debris dam on the surface of the blockage and recent studies of theblockage stratigraphy and soil properties showing that the effective crest elevation is lower than the surface crest have led to concern that the lake may someday breach through or spill over the top of the blockage. A study was made by the U.S. Geological Survey to determine the extent of inundation that might result downstream in the Toutle and Cowlitz Rivers if a hypothetical breach should occur and generate a mudflow flood of catastrophic proportions. A hypothetical breach of Spirit Lake produced a hypothetical mudflow hydrograph with a peak discharge of 2.65 million cu ft/s and a sediment concentration of 65 percent by volume at Camp Baker on the North Fork Toutle River. Elevations determined by the hydraulic routing of the mudflow were used to prepare inundation maps, indicating depths of inundation to be about 60 feet at Castle Rock and Lexington; 30-40 feet at Toutle, Toutle Lake at Silver Lake, Kelson, and Longview; and 15-20 feet at Toledo. Travel times for the peak elevation were estimated to be about 15 hours to Kid Valley on the North Fork Toutle River, 21 hours to Castle Rock, 22 hours to Toledo, and 23 hours to Kelso and Longview on the Cowlitz River. (USGS)

  5. Ghrelin Inhibits Post-Operative Adhesions via Blockage of the TGF-β Signaling Pathway

    PubMed Central

    Bianchi, Enrica; Boekelheide, Kim; Sigman, Mark; Lamb, Dolores J.; Hall, Susan J.; Hwang, Kathleen

    2016-01-01

    Post-operative adhesions are a critical problem in pelvic and abdominal surgery despite a multitude of studies dedicated to finding modalities to prevent their occurrence. Ghrelin administration promotes an anti-fibrotic response in a surgical mouse model of adhesion-induction, but the mechanisms mediating this effect have not been established. In the current study, the molecular mechanisms that underlie the anti-adhesion effect of ghrelin were investigated. Post-surgical adhesions were experimentally created in C57BL/6 wild-type mice via a combination of ischemic peritoneal buttons and cecal multiple abrasions. Ghrelin or saline intraperitoneal injections were given twice daily from two days before surgery to selected time points post-surgically to assess the phenotypic and molecular effects of treatment (1 day (n = 20), 4 days (n = 20) and 20 days (n = 40) after surgery). Endpoints included the scoring of adhesions and gene and protein expression analysis of pro-fibrogenic factors conducted on peritoneal ischemic tissue by quantitative PCR and Western blot. Ghrelin administration significantly reduced post-surgical adhesions and down-regulated pro-inflammatory gene and protein expression, including Tgfb3 and Tgfbr2. The up-regulation of inhibitory proteins Smad6 and Smad7 confirmed the ghrelin-induced blockage of TGF-β signaling. Ghrelin is a candidate therapeutic drug for post-operative adhesion prevention, inhibiting inflammatory responses via blockage of the TGF-β signaling pathway at the onset of surgery before the occurrence of the granulation-remodeling phase. PMID:27082244

  6. Model-based reasoning: Troubleshooting

    NASA Astrophysics Data System (ADS)

    Davis, Randall; Hamscher, Walter C.

    1988-07-01

    To determine why something has stopped working, its useful to know how it was supposed to work in the first place. That simple observation underlies some of the considerable interest generated in recent years on the topic of model-based reasoning, particularly its application to diagnosis and troubleshooting. This paper surveys the current state of the art, reviewing areas that are well understood and exploring areas that present challenging research topics. It views the fundamental paradigm as the interaction of prediction and observation, and explores it by examining three fundamental subproblems: generating hypotheses by reasoning from a symptom to a collection of components whose misbehavior may plausibly have caused that symptom; testing each hypothesis to see whether it can account for all available observations of device behavior; then discriminating among the ones that survive testing. We analyze each of these independently at the knowledge level i.e., attempting to understand what reasoning capabilities arise from the different varieties of knowledge available to the program. We find that while a wide range of apparently diverse model-based systems have been built for diagnosis and troubleshooting, they are for the most part variations on the central theme outlined here. Their diversity lies primarily in the varying amounts of kinds of knowledge they bring to bear at each stage of the process; the underlying paradigm is fundamentally the same.

  7. Infant Approach and Withdrawal in Response to a Goal Blockage: Its Antecedent Causes and Its Effect on Toddler Persistence

    ERIC Educational Resources Information Center

    Lewis, Michael; Sullivan, Margaret W.; Kim, Hillary Mi-Sung

    2015-01-01

    In 2 separate longitudinal studies, infants and their mothers were seen in 3 longitudinal visits. At 2 months, they were observed in free play where mothers' contingency toward their infants was obtained. At 5 months, a goal blockage response was produced when a previously learned contingent response became ineffective in producing an interesting…

  8. Wind-tunnel blockage and actuation systems test of a two-dimensional scramjet inlet unstart model at Mach 6

    NASA Technical Reports Server (NTRS)

    Holland, Scott D.

    1994-01-01

    The present study examines the wind-tunnel blockage and actuation systems effectiveness in starting and forcibly unstarting a two-dimensional scramjet inlet in the NASA Langley 20-Inch Mach 6 Tunnel. The intent of the overall test program is to study (both experimentally and computationally) the dynamics of the inlet unstart; however, prior to the design and fabrication of an expensive, instrumented wind-tunnel model, it was deemed necessary first to examine potential wind-tunnel blockage issues related to model sizing and to examine the adequacy of the actuation systems in accomplishing the start and unstart. The model is equipped with both a moveable cowl and aft plug. Windows in the inlet sidewalls allow limited optical access to the internal shock structure; schlieren video was used to identify inlet start and unstart. A chronology of each actuation sequence is provided in tabular form along with still frames from the schlieren video. A pitot probe monitored the freestream conditions throughout the start/unstart process to determine if there was a blockage effect due to the model start or unstart. Because the purpose of this report is to make the phase I (blockage and actuation systems) data rapidly available to the community, the data is presented largely without analysis of the internal shock interactions or the unstart process. This series of tests indicated that the model was appropriately sized for this facility and identified operability limits required first to allow the inlet to start and second to force the unstart.

  9. PWR FLECHT SEASET 21-rod bundle flow blockage task data and analysis report. NRC/EPRI/Westinghouse Report No. 11. Appendices K-P

    SciTech Connect

    Loftus, M.J.; Hochreiter, L.E.; Lee, N.; McGuire, M.F.; Wenzel, A.H.; Valkovic, M.M.

    1982-09-01

    This report presents data and limited analysis from the 21-Rod Bundle Flow Blockage Task of the Full-Length Emergency Cooling Heat Transfer Separate Effects and Systems Effects Test Program (FLECHT SEASET). The tests consisted of forced and gravity reflooding tests utilizing electrical heater rods with a cosine axial power profile to simulate PWR nuclear core fuel rod arrays. Steam cooling and hydraulic characteristics tests were also conducted. These tests were utilized to determine effects of various flow blockage configurations (shapes and distributions) on reflooding behavior, to aid in development/assessment of computational models in predicting reflooding behavior of flow blockage configurations, and to screen flow blockage configurations for future 163-rod flow blockage bundle tests.

  10. Parametric study of the potential for BWR ECCS strainer blockage due to LOCA generated debris. Final report

    SciTech Connect

    Zigler, G.; Brideau, J.; Rao, D.V.; Shaffer, C.; Souto, F.; Thomas, W.

    1995-10-01

    This report documents a plant-specific study for a BWR/4 with a Mark I containment that evaluated the potential for LOCA generated debris and the probability of losing long term recirculation capability due ECCS pump suction strainer blockage. The major elements of this study were: (1) acquisition of detailed piping layouts and installed insulation details for a reference BWR; (2) analysis of plant specific piping weld failure probabilities to estimate the LOCA frequency; (3) development of an insulation and other debris generation and drywell transport models for the reference BWR; (4) modeling of debris transport in the suppression pool; (5) development of strainer blockage head loss models for estimating loss of NPSH margin; (6) estimation of core damage frequency attributable to loss of ECCS recirculation capability following a LOCA. Elements 2 through 5 were combined into a computer code, BLOCKAGE 2.3. A point estimate of overall DEGB pipe break frequency (per Rx-year) of 1.59E-04 was calculated for the reference plant, with a corresponding overall ECCS loss of NPSH frequency (per Rx-year) of 1.58E-04. The calculated point estimate of core damage frequency (per Rx-year) due to blockage related accident sequences for the reference BWR ranged from 4.2E-06 to 2.5E-05. The results of this study show that unacceptable strainer blockage and loss of NPSH margin can occur within the first few minutes after ECCS pumps achieve maximum flows when the ECCS strainers are exposed to LOCA generated fibrous debris in the presence of particulates (sludge, paint chips, concrete dust). Generic or unconditional extrapolation of these reference plant calculated results should not be undertaken.

  11. Non-amyloid and amyloid prion protein deposits in prion-infected mice differ in blockage of interstitial brain fluid

    PubMed Central

    Rangel, Alejandra; Race, Brent; Striebel, James; Chesebro, Bruce

    2012-01-01

    Aims Prion diseases are characterized by brain deposits of misfolded aggregated protease-resistant prion protein (PrP), termed PrPres. In humans and animals, PrPres is found as either disorganized non-amyloid aggregates or organized amyloid fibrils. Both PrPres forms are found in extracellular spaces of the brain. Thus, both might block drainage of brain interstitial fluid (ISF). The present experiments studied whether ISF blockage occurred during amyloid and/or non-amyloid prion diseases. Methods Various-sized fluorescein-labeled ISF tracers were stereotactically inoculated into the striatum of adult mice. At times from 5 min to 77 hours, uninfected and scrapie-infected mice were compared. C57BL/10 mice expressing wild-type anchored PrP, which develop non-amyloid PrPres similar to humans with sporadic CJD, were compared with Tg44+/+ mice expressing anchorless PrP, which develop amyloid PrPres similar to certain human familial prion diseases. Results In C57BL/10 mice, extensive non-amyloid PrPres aggregate deposition was not associated with abnormal clearance kinetics of tracers. In contrast, scrapie-infected Tg44+/+ mice showed blockage of tracer clearance and co-localization of tracer with perivascular PrPres amyloid. Conclusions Since tracer localization and clearance was normal in infected C57BL/10 mice, ISF blockage was not an important pathogenic mechanism in this model. Therefore, ISF blockage is unlikely to be a problem in non-amyloid human prion diseases such as sporadic CJD. In contrast, partial ISF blockage appeared to be a possible pathogenic mechanism in Tg44+/+ mice. Thus this mechanism might also influence human amyloid prion diseases where expression of anchorless or mutated PrP results in perivascular amyloid PrPres deposition and cerebral amyloid angiopathy (CAA). PMID:22998478

  12. Gas Transport Parameters for Landfill Cover Soils: Effects of Soil Compaction and Water Blockages

    NASA Astrophysics Data System (ADS)

    Wickramarachchi, P. N.; Hamamoto, S.; Kawamoto, K.; Nawagamuwa, U.; Komatsu, T.; Moldrup, P.

    2009-12-01

    Recently, landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric CH4. landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest source of anthropogenic CH4 emission , the final cover system should also be designed for minimizing the biogas migration into the atmosphere or the areas surrounding the landfill. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil , there are few studies about gas transport characteristics of landfill cover soils. Therefore, the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size and water blockage effects on the gas exchange in t highly compacted final cover soil are largely unknown. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport . In this study, the effects of compaction level and water blockage effects on ka and Dp for two landfill final cover soils were investigated. The disturbed soil samples were taken from landfill final covers in Japan and Sri Lanka. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm) at two different compaction levels (2700 kN/m2 and 600 kN/m2). After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential (pF; pF equals to log(-ɛ) where ɛ is soil-water matric potential in cm H2O) of 1.5, 2.0, 3.0, 4.1, and with air-dried (pF 6.0) and oven-dried (pF 6.9) conditions. Results showed that measured Dp values

  13. Re-Analysis of Hydroacoustic Fish-Passage Data from Bonneville Dam after Spill-Discharge Corrections

    SciTech Connect

    Ploskey, Gene R.; Kim, Jina; Weiland, Mark A.; Hughes, James S.; Fischer, Eric S.

    2007-06-07

    The U.S. Army Corps of Engineers - Portland District asked Pacific Northwest National Laboratory to re-analyze four years of fixed-aspect hydroacoustic data after the District made adjustments to spill discharge estimates. In this report, we present new estimates of all major fish-passage metrics for study years 2000, 2001, 2002, and 2004, as well as estimates for 2005. This study supports the Portland District and its effort to maximize survival of juvenile salmon passing Bonneville Dam. Major passage routes through Bonneville Dam include 10 turbines and a sluiceway at Powerhouse 1 (B1), an 18-bay spillway, and eight turbines at Powerhouse 2 (B2) and a sluiceway including the B2 Corner Collector. The original reports and all associated results, discussion, and conclusions for non flow-related metrics remain valid and useful, but effectiveness measures for study years 2000, 2001, 2002, and 2004 as reported in previous reports by Ploskey et al. should be superseded with the new estimates reported here. The fish-passage metrics that changed the most were related to effectiveness. Re-analysis produced spill effectiveness estimates that ranged from 12% to 21% higher than previous estimates in spring and 16.7% to 27.5% higher in summer, but the mean spill effectiveness over all years was only slightly above 1:1 (1.17 for spring and 1.29 for summer). Conversely surface-passage effectiveness decreased in the years this metric was measured (by 10.1% in spring and 10.7% in summer of 2002 and 9.5% in spring and 10.2% in summer of 2004). The smallest changes in the re-analysis were in project fish passage efficiency (0%-1%) and spill efficiency (0.9%-3.0%).

  14. Mapping and Monitoring of Dynamic Seafloor Features with Hydroacoustic Devices in Sandy Coastal Areas (German Bight, North Sea)

    NASA Astrophysics Data System (ADS)

    Papenmeier, S.; Mielck, F.; Hass, H. C.

    2014-12-01

    In order to understand marine ecosystems and to provide basic data for a sustainable management in these vulnerable areas, seafloor mapping has become increasingly important. Since the knowledge regarding the seabed environments and their dynamics are still sparse, new mapping techniques have evolved in the last years and hydroacoustic devices became an important tool for quick and reliable mapping. In 2007 we started a monitoring program in the German Bight (North Sea) using sidescan sonar (Imagenex YellowFin, 330 kHz) in a study site comprising approximately 1,500 km2. In subsequent years, the area was mapped repeatedly with a resolution of ~25 cm. For ground truthing, several hundred sediment samples were taken. The investigations reveal that the area is mainly characterized by fine to coarse sand which is arranged in different seafloor features such as subaquatic dunes or relicts of Pleistocene moraines. While the alignment and position of the moraines was stable throughout the years, the dunes can be highly dynamic. Their migration indicates the amount of sediment transport in these areas. Some seafloor features could be identified as so-called sorted bedforms, which are spatially-grain-size-sorted patterns on the seafloor consisting of small rippled medium sand surrounded by smooth fine sand. These flow-transverse features are morphological linked to ridges and depressions and are further maintained by ebb and flood currents of almost equal strengths. The medium sand is separated from the fine sand by sharp boundaries in all directions which were generated by the bidirectional flow field. The extend and alignment of the sorted bedforms seem to be relatively stable in a time frame of 6 years, however small-scale variabilities up to serveral meters could be detected. We suppose that these processes mainly occur during storm surges while the fine-sand layers are winnowed away and hence the shapes of the bedforms changes.

  15. Model-based Utility Functions

    NASA Astrophysics Data System (ADS)

    Hibbard, Bill

    2012-05-01

    Orseau and Ring, as well as Dewey, have recently described problems, including self-delusion, with the behavior of agents using various definitions of utility functions. An agent's utility function is defined in terms of the agent's history of interactions with its environment. This paper argues, via two examples, that the behavior problems can be avoided by formulating the utility function in two steps: 1) inferring a model of the environment from interactions, and 2) computing utility as a function of the environment model. Basing a utility function on a model that the agent must learn implies that the utility function must initially be expressed in terms of specifications to be matched to structures in the learned model. These specifications constitute prior assumptions about the environment so this approach will not work with arbitrary environments. But the approach should work for agents designed by humans to act in the physical world. The paper also addresses the issue of self-modifying agents and shows that if provided with the possibility to modify their utility functions agents will not choose to do so, under some usual assumptions.

  16. Flood hazards along the Toutle and Cowlitz rivers, Washington, from a hypothetical failure of Castle Lake blockage

    USGS Publications Warehouse

    Laenen, Antonius; Orzol, L.L.

    1987-01-01

    A recent evaluation of groundwater and material in the blockage impounding Castle Lake shows that the blockage is potentially unstable against failure from piping due to heave and internal erosion when groundwater levels are seasonally high. There is also a remote possibility that a 6.8 or greater magnitude earthquake could occur in the Castle Lake area when groundwater levels are critically high. If this situation occurs, the debris blockage that confines Castle Lake could breach from successive slope failure with liquefaction of a portion of the blockage. A dam-break computer model was used to simulate discharge through a hypothetical breach in the Castle Lake blockage that could be caused by failure by heave, internal erosion, or liquefaction. Approximately 18,500 acre-ft of stored water would be released from an assumed breach that fully developed to a 1,000-ft width over a 15-minute time period. The resulting flood, incorporating 3.4 x 10 to the 6th power cu yd of the debris blockage, would reach a peak magnitude of 1,500,000 cu ft/s (cubic feet per second). The flood is also assumed to incorporate an additional 137x10 to the 6th power cu yd of saturated debris material from downstream deposits. Flow is considered to be hyperconcentrated with sediment throughout the course of the flood. The hypothetical hyperconcentrated flow is routed downstream, superimposed on normal winter flood flows by use of a one-dimensional unsteady-state numerical streamflow simulation model. From a starting magnitude of 1,500,000 cu ft/s, the peak increases to 2,100,000 cu ft/s at N-1 Dam (12 mi downstream) and attenuates to 1,200,000 cu ft/s at Kid Valley (25 mi downstream) , to 100,000 cu ft/s at Longview and the confluence of the Columbia River (65 mi downstream). From time of breach, the flood peak would take 2.2 hr to reach Toutle, 3.8 hr to reach Castle Rock, and 8.5 hr to reach Longview. Communities of Toutle , Castle Rock, Kelso, and Longview would experience extreme to

  17. Angiotensin-II blockage, muscle strength, and exercise capacity in physically independent older adults

    PubMed Central

    Coelho, Vinícius A.; Probst, Vanessa S.; Nogari, Bruna M.; Teixeira, Denilson C.; Felcar, Josiane M.; Santos, Denis C.; Gomes, Marcus Vinícius M.; Andraus, Rodrigo A. C.; Fernandes, Karen B. P.

    2016-01-01

    [Purpose] This study aimed to assess the exercise capacity and muscle strength in elderly people using drugs for angiotensin-II blockage. [Subjects and Methods] Four hundred and seven older adults were recruited for this study. Data about comorbidities and medication use were recorded and the individuals were divided into three groups: control group- elderly people with normal exercise capacity (n=235); angiotensin-converting enzyme inhibitor group − individuals using angiotensin-converting enzyme inhibitors (n=140); and angiotensin-II receptor blocker group- patients using angiotensin-II receptor blockers (n= 32). Exercise capacity was evaluated by a 6-minute walking test and muscle strength was measured using a handgrip dynamometer. [Results] Patients from the angiotensin-converting enzyme inhibitor group (mean: 99 ± 12%) and the angiotensin-II receptor blocker group (mean: 101 ± 14%) showed higher predicted values in the 6-minute walking test than the control group patients (mean: 96 ± 10%). Patients from the angiotensin-converting enzyme inhibitor group (mean: 105 ± 19%) and the angiotensin-II receptor blocker group (mean: 105.1 ± 18.73%) showed higher predicted values of muscle strength than control group patients (mean: 98.15 ± 18.77%). [Conclusion] Older adults using angiotensin-converting enzyme inhibitors or angiotensin-II receptor blockers have better functional exercise capacity and muscle strength. PMID:27065543

  18. Upstream blockage effect on the thrust force of a marine hydrokinetic device

    NASA Astrophysics Data System (ADS)

    Soliani, Giulio; Beninati, Maria Laura; Krane, Michael; Fontaine, Arnold

    2013-11-01

    The study evaluates the interaction of two model marine devices axially arranged one in front of the other, in a tandem configuration. Particular focus is given to the change that occurs in the thrust of the downstream marine hydrokinetic (MHK) device when the spatial arrangement of the two elements is varied. At critical spacing there is no thrust generation. The study is motivated by the need to predict the thrust behavior of MHK devices and determine the minimum separation distance to avoid the no thrust condition. The downstream element is a two-bladed, horizontal axis turbine, while the upstream blockage is a perforated disk with similar geometric properties intended to approximate the wake of the MHK device. Testing is conducted in the flume facility at Bucknell University. Experiments are performed for a fixed range of spacing between the perforated disk and the turbine. For each separation distance, the span-wise velocity profile upstream and downstream of the turbine is measured, as well as the device's rotational speed. The turbine's thrust coefficient is calculated. Plots of the thrust coefficient as a function of spacing depict the minimum separation distance to avoid the no thrust condition.

  19. Simulation of malaria-infected red blood cells in microfluidic channels: Passage and blockage

    PubMed Central

    Wu, Tenghu; Feng, James J.

    2013-01-01

    Malaria-infected red blood cells (iRBCs) become less deformable with the progression of infection and tend to occlude microcapillaries. This process has been investigated in vitro using microfluidic channels. The objective of this paper is to provide a quantitative basis for interpreting the experimental observations of iRBC occlusion of microfluidic channels. Using a particle-based model for the iRBC, we simulate the traverse of iRBCs through a converging microfluidic channel and explore the progressive loss of cell deformability due to three factors: the stiffening of the membrane, the reduction of the cell's surface-volume ratio, and the growing solid parasites inside the cell. When examined individually, each factor tends to hinder the passage of the iRBC and lengthen the transit time. Moreover, at sufficient magnitude, each may lead to obstruction of narrow microfluidic channels. We then integrate the three factors into a series of simulations that mimic the development of malaria infection through the ring, trophozoite, and schizont stages. These simulations successfully reproduce the experimental observation that with progression of infection, the iRBC transitions from passage to blockage in larger and larger channels. The numerical results suggest a scheme for quantifying iRBC rigidification through microfluidic measurements of the critical pressure required for passage. PMID:24404048

  20. Blockage and flow: intimate experiences of condoms and microbicides in a South African clinical trial.

    PubMed

    Stadler, Jonathan; Saethre, Eirik

    2011-01-01

    Based on qualitative research undertaken during a phase-three microbicide gel trial, this paper explores female participants' experiences and perceptions of gel and condom use and the opinions of their male partners and community members. Participants were aware that condoms were effective in preventing HIV infection and that the efficacy of the microbicide was unproven. Yet, in narratives about gel and condom use, participants ascribed improvements to their reproductive health and intimate relationships with men to gel use. In contrast, condoms were believed to prevent disease, yet also embodied mistrust, were believed to contain dangerous substances and were felt to block the womb. These apparently contradictory views about condoms and gels are explored in the light of conceptions of flow and blockage. Health is achieved by maintaining a steady balance of substances within the body, while preventing fluid flow results in illness. We argue that women enrolled in the trial broadened the meaning of the gel beyond its primary intended effect of preventing HIV. Through their accounts of gel use, women 'reinvented' the gel as a substance that transformed their bodies and sexual relations. This has implications for understanding how local knowledge of health and illness intersects with biomedical knowledge. PMID:20960355

  1. Blockage of the transduction channels of hair cells in the bullfrog's sacculus by aminoglycoside antibiotics.

    PubMed

    Kroese, A B; Das, A; Hudspeth, A J

    1989-02-01

    The action of aminoglycoside antibiotics on transduction by hair cells was investigated in isolated preparations of the bullfrog's sacculus. Bath application of aminoglycosides produced a reversible blockage of extracellularly recorded responses to displacements of the otolithic membrane. The half-blocking concentrations for various drugs were in the range 2-95 microM. The effect of dihydrostreptomycin on the receptor currents of individual hair cells was studied under two-electrode, voltage-clamp conditions. Iontophoretic application of drug to the apical cellular surface caused a reduction of the receptor current within 20 ms; the reduction was reversible within 1 s. The effect was most striking at holding potentials more negative than -60 mV and was relieved by depolarization. The effect of intracellular aminoglycosides was investigated in cells voltage-clamped with the tight-seal, whole-cell technique. Gentamicin and dihydrostreptomycin, at concentrations near 100 microM, did not block transduction under these conditions. The acute, reversible blocking effect of aminoglycosides therefore occurs from the extracellular membrane surface. The results are consistent with aminoglycosides' plugging the poorly ion-selective transduction channels of hair cells. PMID:2468634

  2. Tolerogenic Dendritic Cells on Transplantation: Immunotherapy Based on Second Signal Blockage

    PubMed Central

    Silva, Priscila de Matos; Bier, Julia; Paiatto, Lisiery Negrini; Galdino Albuquerque, Cassia; Lopes Souza, Caique; Fernandes, Luis Gustavo Romani; Tamashiro, Wirla Maria da Silva Cunha; Simioni, Patricia Ucelli

    2015-01-01

    Dendritic cells (DCs), the most important professional antigen-presenting cells (APC), play crucial role in both immunity and tolerance. It is well known that DCs are able to mount immune responses against foreign antigens and simultaneously tolerate self-antigens. Since DCs can be modulated depending on the surrounding microenvironment, they can act as a bridge between innate and adaptive immunity. However, the mechanisms that support this dual role are not entirely clear. Recent studies have shown that DCs can be manipulated ex vivo in order to trigger their tolerogenic profile, what can be a tool to be used in clinical trials aiming the treatment of various diseases and the prevention of transplant rejection. In this sense, the blockage of costimulatory molecules on DC, in the attempt of inhibiting the second signal in the immunological synapse, can be considered as one of the main strategies under development. This review brings an update on current therapies using tolerogenic dendritic cells modulated with costimulatory blockers with the aim of reducing transplant rejection. However, although there are current clinical trials using tolerogenic DC to treat allograft rejection, the actual challenge is to modulate these cells in order to maintain a permanent tolerogenic profile. PMID:26543876

  3. Why are Foley catheters so vulnerable to encrustation and blockage by crystalline bacterial biofilm?

    PubMed

    Stickler, David; Young, Robert; Jones, Gwennan; Sabbuba, Nora; Morris, Nicola

    2003-10-01

    Many patients undergoing long-term bladder catheterisation experience blockage and encrustation of their catheters. The problem stems from infection by urease producing bacteria, particularly Proteus mirabilis. Bacterial biofilms colonise the catheters, the activity of urease raises the pH and induces the deposition of calcium and magnesium phosphate crystals. In this study, a laboratory model of the catheterised bladder has been used to examine the early stages in the formation of the crystalline biofilms. The results show that initial cell adhesion is to the irregular surfaces surrounding the catheter eye-holes. Microcolonies form in depressions in these surfaces and spread to cover the entire surface of the rims around the eye-holes. Crystals then form around the bacterial populations and the biofilm starts to move down the lumenal surfaces of the catheters. The encrustation develops most extensively and generally blocks the catheter at or just below the eye-hole. There is a need to improve catheter design and manufacturing procedures for the eye-holes if the problems associated with the current devices are to be reduced. PMID:14574534

  4. Proteomic profiling of ATM kinase proficient and deficient cell lines upon blockage of proteasome activity☆

    PubMed Central

    Marzano, Valeria; Santini, Simonetta; Rossi, Claudia; Zucchelli, Mirco; D'Alessandro, Annamaria; Marchetti, Carlo; Mingardi, Michele; Stagni, Venturina; Barilà, Daniela; Urbani, Andrea

    2012-01-01

    Ataxia Telangiectasia Mutated (ATM) protein kinase is a key effector in the modulation of the functionality of some important stress responses, including DNA damage and oxidative stress response, and its deficiency is the hallmark of Ataxia Telangiectasia (A-T), a rare genetic disorder. ATM modulates the activity of hundreds of target proteins, essential for the correct balance between proliferation and cell death. The aim of this study is to evaluate the phenotypic adaptation at the protein level both in basal condition and in presence of proteasome blockage in order to identify the molecules whose level and stability are modulated through ATM expression. We pursued a comparative analysis of ATM deficient and proficient lymphoblastoid cells by label-free shotgun proteomic experiments comparing the panel of proteins differentially expressed. Through a non-supervised comparative bioinformatic analysis these data provided an insight on the functional role of ATM deficiency in cellular carbohydrate metabolism's regulation. This hypothesis has been demonstrated by targeted metabolic fingerprint analysis SRM (Selected Reaction Monitoring) on specific thermodynamic checkpoints of glycolysis. This article is part of a Special Issue entitled: Translational Proteomics. PMID:22641158

  5. Blockage of progestin physiology disrupts ovarian differentiation in XX Nile tilapia (Oreochromis niloticus).

    PubMed

    Zhou, Linyan; Luo, Feng; Fang, Xuelian; Charkraborty, Tapas; Wu, Limin; Wei, Jing; Wang, Deshou

    2016-04-22

    Previous studies indicated that maturation inducing hormone, 17α, 20β-Dihydroxy-4-pregnen-3-one (DHP), probably through nuclear progestin receptor (Pgr), might be involved in spermatogenesis and oogenesis in fish. To further elucidate DHP actions in teleostean ovarian differentiation, we analyzed the expression of pgr in the ovary of Nile tilapia (Oreochromis niloticus), and performed RU486 (a synthetic Pgr antagonist) treatment in XX fish from 5 days after hatching (dah) to 120dah. Tilapia Pgr was abundantly expressed in the follicular cells surrounding oocytes at 30 and 90dah. Continuous RU486 treatment led to the blockage of oogenesis and masculinization of somatic cells in XX fish. Termination of RU486 treatment and maintenance in normal condition resulted in testicular differentiation, and estrogen compensation in RU486-treated XX fish successfully restored oogenesis. In RU486-treated XX fish, transcript levels of female dominant genes were significantly reduced, while male-biased genes were evidently augmented. Meanwhile, both germ cell mitotic and meiotic markers were substantially reduced. Consistently, estrogen production levels were significantly declined in RU486-treated XX fish. Taken together, our data further proved that DHP, possibly through Pgr, might be essential in the ovarian differentiation and estrogen production in fish. PMID:26993165

  6. PWR FLECHT SEASET 163-Rod Bundle Flow Blockage Task data report. NRC/EPRI/Westinghouse report No. 13, August-October 1982

    SciTech Connect

    Loftus, M J; Hochreiter, L E; McGuire, M F; Valkovic, M M

    1983-10-01

    This report presents data from the 163-Rod Bundle Blow Blockage Task of the Full-Length Emergency Cooling Heat Transfer Systems Effects and Separate Effects Test Program (FLECHT SEASET). The task consisted of forced and gravity reflooding tests utilizing electrical heater rods with a cosine axial power profile to simulate PWR nuclear core fuel rod arrays. These tests were designed to determine effects of flow blockage and flow bypass on reflooding behavior and to aid in the assessment of computational models in predicting the reflooding behavior of flow blockage in rod bundle arrays.

  7. Seismicity and active accretion processes at the ultraslow-spreading Southwest and intermediate-spreading Southeast Indian ridges from hydroacoustic data

    NASA Astrophysics Data System (ADS)

    Tsang-Hin-Sun, Eve; Royer, Jean-Yves; Perrot, Julie

    2016-08-01

    Volcanic and tectonic events are the main processes involved in the generation of the oceanic crust and responsible for the seismicity associated with seafloor spreading. To monitor this activity, usually not or poorly detected by land-based seismological stations, we deployed from February 2012 to February 2013 a network of autonomous hydrophones to compare the behaviour of the ultraslow-spreading Southwest Indian ridge (SWIR) with that of the intermediate-spreading Southeast Indian ridge (SEIR). The rate of seismicity is similar for both ridges, suggesting that there is no systematic relationship between seismicity and spreading rates. The along-axis distribution of the seismic events, however, does differ, reflecting the rate dependence of accretion modes. Earthquakes are sparse and regularly spaced and scattered along the SWIR, reflecting prevailing tectonic processes. By contrast, along the SEIR, events are irregularly distributed and focus at ridge-segment ends and transforms faults, reflecting the ridge segmentation; only two swarms occurred at a segment centre and are probably caused by a magmatic event. This seismicity distribution thus looks controlled by segment-scale crustal heterogeneities along the SEIR and by regional-scale contrasting accretion processes along the SWIR, probably driven by different lithospheric and asthenospheric dynamics on either side of the Melville fracture zone. The comparison of hydroacoustic and teleseismic catalogues shows that, along these spreading ridges, the background seismicity observed in 1 yr by a hydroacoustic network is representative of the seismicity observed over two decades by land-based networks.

  8. Seismicity and active accretion processes at the ultraslow-spreading Southwest and intermediate-spreading Southeast Indian ridges from hydroacoustic data

    NASA Astrophysics Data System (ADS)

    Tsang-Hin-Sun, Eve; Royer, Jean-Yves; Perrot, Julie

    2016-05-01

    Volcanic and tectonic events are the main processes involved in the generation of the oceanic crust and responsible for the seismicity associated with seafloor spreading. To monitor this activity, usually not or poorly detected by land-based seismological stations, we deployed from February 2012 to February 2013 a network of autonomous hydrophones to compare the behaviour of the ultraslow-spreading Southwest (SWIR) with that of the intermediate-spreading Southeast Indian ridges (SEIR). The rate of seismicity is similar for both ridges, suggesting that there is no systematic relationship between seismicity and spreading rates. The along-axis distribution of the seismic events, however, does differ, reflecting the rate-dependence of accretion modes. Earthquakes are sparse and regularly spaced and scattered along the SWIR, reflecting prevailing tectonic processes. By contrast, along the SEIR, events are irregularly distributed and focus at ridge-segment ends and transforms faults, reflecting the ridge segmentation; only two swarms occurred at a segment centre and are probably caused by a magmatic event. This seismicity distribution thus looks controlled by segment-scale crustal heterogeneities along the SEIR and by regional-scale contrasting accretion processes along the SWIR, probably driven by different lithospheric and asthenospheric dynamics on either side of the Melville FZ. The comparison of hydroacoustic and teleseismic catalogues shows that, along these spreading ridges, the background seismicity observed in one year by a hydroacoustic network is representative of the seismicity observed over two decades by land-based networks.

  9. Estimation of the Rupture Length and Velocity for Both the Dec 26, 2004 and March 28, 2005 Events Using Hydroacoustic Signals

    NASA Astrophysics Data System (ADS)

    Degroot-Hedlin, C.

    2005-05-01

    Unprecedented hydroacoustic observations of the both the megathrust earthquake of 26 Dec, 2004 and the subsequent March 28, 2005 event were afforded by a network of 5 small hydroacoustic arrays located in the Indian Ocean, at distances of 2800 to 7000 km from the epicenter. Each array consists of three hydrophones, configured as a triangle with sides of approximately 2 km length, moored at or near the depth of the ocean sound speed minimum. The array configuration allows for precise determination of the receiver to source azimuth for a series of short time segments within the coda, given coherent arrivals across the array. Both events generated acoustic waves, called T-waves, that were recorded on all 5 arrays. For each event, analysis of a series of short time windows within the T-wave coda shows that the receiver to source azimuth varies smoothly as a function of time, indicating that the apparent T-wave source is not stationary. For the 26 Dec event, the apparent T-wave source moves northward along the Sunda trench at an average velocity of 2km/s for a distance of nearly 900km. For the March 28 event, the source appears to move southward at an average velocity of 2km/sec for a distance of about 300km. However, the estimates are less certain for the second event.

  10. Benthic habitat mapping of sorted bedforms using hydroacoustic and ground-truthing methods in a coastal area of the German Bight/North Sea

    NASA Astrophysics Data System (ADS)

    Markert, Edith; Holler, Peter; Kröncke, Ingrid; Bartholomä, Alexander

    2013-09-01

    The continuously influence of human impacts on the seafloor and benthic habitats demands the knowledge of clearly defined habitats to assess recent conditions and to monitor future changes. In this study, a benthic habitat dominated by sorted bedforms was mapped in 2010 using biological, sedimentological and acoustic data. This approach reveals the first interdisciplinary analysis of macrofauna communities in sorted bedforms in the German Bight. The study area covered 4 km2, and was located ca. 3.5 km west of island of Sylt. Sorted bedforms formed as sinuous depressions with an east west orientation. Inside these depressions coarse sand covers the seafloor, while outside predominantly fine to medium sand was found. Based on the hydroacoustic data, two seafloor classes were identified. Acoustic class 1 was linked to coarse sand (type A) found inside these sorted bedforms, whereas acoustic class 2 was related to mainly fine to medium sands (type B). The two acoustic classes and sediment types corresponded with the macrofauna communities 1 and 2. The Aoinides paucibranchiata-Goniadella bobretzkii community on coarse sand and the Spiophanes bombyx - Magelona johnstonii community on fine sand. A transitional community 3 (Scoloplos armiger - Ophelia community), with species found in communities 1 and 2, could not be detected by hydroacoustic methods. This study showed the limits of the used acoustic methods, which were unable to detect insignificant differences in the fauna composition of sandy areas.

  11. Blending single beam RoxAnn and multi-beam swathe QTC hydro-acoustic discrimination techniques for the Stonehaven area, Scotland, UK

    NASA Astrophysics Data System (ADS)

    Serpetti, Natalia; Heath, Mike; Armstrong, Eric; Witte, Ursula

    2011-05-01

    Surface properties of the seabed in a 180 km 2 area of coastal waters (14-57 m depth) off northeast Scotland were mapped by hydro-acoustic discrimination using single and multi-beam echosounders linked to signal processing systems (RoxAnn for the single beam, and Questor Tangent Corporation (QTC) Multiview for the multibeam). Subsequently, two ground truthing surveys were carried out, using grab and TV sampling. The RoxAnn and QTC-Multiview outputs showed strong similarity in their classifications of seabed types. Classifications generated by QTC-Multiview were used to supervise those based on seabed roughness and hardness indices produced by the RoxAnn system and thereby develop a 'blended' map based on both systems. The resulting hydro-acoustic classes agreed well with a cluster analysis of data on sediment grain sizes from the grab sampling, and indicated that the area could be described by distinct regions of surface texture and surficial sediments ranging from muddy sand to boulders and rock.

  12. Hydroacoustic Studies Using HydroCAM - Station-centric Integration of Models and Observations Quarterly Report No. 3 April 2003 - June 2003

    SciTech Connect

    Pulli, Jay J.; Upton, Zachary M.

    2003-07-14

    OAK A271 Hydroacoustic Studies Using HydroCAM - Station-centric Integration of Models and Observations Quarterly Report No. 3 April 2003 - June 2003. BBN's work from April through June of 2003 was focused on the testing and release of HydroCAM 4.0, development of HydroCAM 4.1 software, continued data collection and analysis, and initial preparations for the 2003 Seismic Research Review. HydroCAM 4.0 was released and sent to DOE and AFTAC on June 9. This is the first release of new software on this contract. The code addresses the problems and issues that BBN and AFTAC had identified in the Fall of 2003. HydroCAM 4.1 is under development. A description of that development is shown in section 3.2. We continued our efforts to collect ground truth hydroacoustic data from sub-sea earthquakes in the Indian Ocean. To date, we have collected over 130 events. These data are recorded on the International Monitoring System stations at Diego Garcia and Cape Leeuwin. Finally, BBN submitted an abstract for the 2003 Seismic Research Review meeting. However, after discussions with Phil Harben at Lawrence Livermore Labs, we have decided to collaborate on one program-wide paper for the meeting.

  13. Simultaneous visualization of oxygen distribution and water blockages in an operating triple-serpentine polymer electrolyte fuel cell

    NASA Astrophysics Data System (ADS)

    Takada, Kenji; Ishigami, Yuta; Inukai, Junji; Nagumo, Yuzo; Takano, Hiroshi; Nishide, Hiroyuki; Watanabe, Masahiro

    2011-03-01

    Visualization inside polymer electrolyte fuel cells (PEFCs) is important for elucidating reaction distributions to improve the performance and durability of the cells. An O2-sensitive porphyrin luminescent dye film was used to visualize oxygen partial pressures and water blockages simultaneously in triple-serpentine gas flow channels in an operating PEFC. Water droplets formed near the exit of a gas-flow channel lowered the oxygen partial pressure noticeably over the channel by blocking air flow near the entrance. Meanwhile, air was continuously supplied from the other channels through the gas diffusion layer, thus allowing power to be generated in the blocked channel. With water blockages, however, the catalyst layer under the channel became flooded by the water produced during the reaction, and the flooded state continued to exist in the catalyst and/or porous layers, even after blowing the water droplet out, so that the power generation was lowered along the channel.

  14. Effect of road blockages on local air pollution during the Hong Kong protests and its implications for air quality management.

    PubMed

    Brimblecombe, Peter; Ning, Zhi

    2015-12-01

    Roadside air quality in urban areas is largely affected by the traffic emissions. Changes in emissions and transport control policy are often assumed to yield benefits in air quality, but have often not always been effective in producing perceptible improvements due to the complexity of meteorological conditions. This study evaluates the air quality before, during and after a temporary roadway blockage event in Hong Kong that took place during Hong Kong protests from late September to mid-December, 2014. The local regulatory air quality monitoring data from both roadside and general ambient stations were used to assess the impact of roadway blockages on the air quality. There was a public perception of improved air quality, but analysis of the data shows the changes can be difficult to discern. This study showed some benefits deriving from road blockages on the local air quality, but the impact was not always apparent because of seasonal variation in meteorological conditions and synoptic transport of pollutants. The finding suggests care is required before making policy changes based on claimed benefits of shifting transport routes. The study highlights the needs to remove seasonal and meteorological change when examining air pollution data to develop strategies to improve air quality. PMID:26245533

  15. Hydroacoustic Evaluation of Overwintering Summer Steelhead Fallback and Kelt Passage at The Dalles Dam Turbines, Early Spring 2011

    SciTech Connect

    Khan, Fenton; Royer, Ida M.

    2012-02-01

    This report presents the results of an evaluation of overwintering summer steelhead (Oncorhynchus mykiss) fallback and early out-migrating steelhead kelts downstream passage at The Dalles Dam turbines during early spring 2011. The study was conducted by Pacific Northwest National Laboratory (PNNL) for the U.S. Army Corps of Engineers, Portland District (USACE) to investigate whether adult steelhead are passing through turbines during early spring before annual sluiceway operations typically begin. The sluiceway surface flow outlet is the optimal non-turbine route for adult steelhead, although operating the sluiceway reduces hydropower production. This is a follow-up study to similar studies of adult steelhead passage at the sluiceway and turbines we conducted in the fall/winter 2008, early spring 2009, fall/winter 2009, and early spring 2010. The goal of the 2011 study was to characterize adult steelhead passage rates at the turbines while the sluiceway was closed so fisheries managers would have additional information to use in decision-making relative to sluiceway operations. Sluiceway operations were not scheduled to begin until April 10, 2011. However, based on a management decision in late February, sluiceway operations commenced on March 1, 2011. Therefore, this study provided estimates of fish passage rates through the turbines, and not the sluiceway, while the sluiceway was open. The study period was March 1 through April 10, 2011 (41 days total). The study objective was to estimate the number and distribution of adult steelhead and kelt-sized targets passing into turbine units. We obtained fish passage data using fixed-location hydroacoustics with transducers deployed at all 22 main turbine units at The Dalles Dam. Adult steelhead passage through the turbines occurred on 9 days during the study (March 9, 12, 30, and 31 and April 2, 3, 5, 7, and 9). We estimated a total of 215 {+-} 98 (95% confidence interval) adult steelhead targets passed through the

  16. Profile blunting and flow blockage in a yield-stress fluid: a molecular dynamics study.

    PubMed

    Varnik, F; Raabe, D

    2008-01-01

    The flow of a simple glass forming system (a 80:20 binary Lennard-Jones mixture) through a planar channel is studied via molecular dynamics simulations. The flow is driven by an external body force similar to gravity. Previous studies show that the model exhibits both a static [F. Varnik, J. Chem. Phys. 120, 2788 (2004)] and a dynamic [F. Varnik and O. Henrich, Phys. Rev. B 73, 174209 (2006)] yield stress in the glassy phase. These observations are corroborated by the present work, where we investigate how the presence of a yield stress may affect the system behavior in a Poiseuille-type flow geometry. In particular, we observe a blunted velocity profile across the channel: A relatively wide region in the channel center flows with a constant velocity (zero shear rate) followed by a nonlinear change of the shear rate as the walls are approached. The observed velocity gradients are compared to those obtained from the knowledge of the shear stress across the channel and the flow curves (stress versus shear rate), the latter being determined in our previous simulations of homogeneous shear flow. Furthermore, using the value of the (dynamic) yield stress known from previous simulations, we estimate the threshold body force for a complete arrest of the flow. Indeed, a blockage is observed as the imposed force falls below this threshold value. Small but finite shear rates are observed at stresses above the dynamic but below the static yield stress. We discuss the possible role of the stick-slip-like motion for this observation. PMID:18351859

  17. Two-Dimensional Scramjet Inlet Unstart Model: Wind-Tunnel Blockage and Actuation Systems Test

    NASA Technical Reports Server (NTRS)

    Holland, Scott D.

    1994-01-01

    This supplement to NASA TM 109152 shows the Schlieren video (10 min. 52 sec., color, Beta and VHS) of the external flow field and a portion of the internal flow field of a two-dimensional scramjet inlet model in the NASA Langley 20-Inch Mach 6 Tunnel. The intent of the overall test program is to study (both experimentally and computationally) the dynamics of the inlet unstart; this (phase I) effort examines potential wind-tunnel blockage issues related to model sizing and the adequacy of the actuation systems in accomplishing the start and unstart. The model is equipped with both a moveable cowl and aft plug. Windows in the inlet sidewalls allow limited optical access to the internal shock structure. In the video, flow is from right to left, and the inlet is oriented inverted with respect to flight, i.e., with the cowl on top. The plug motion is obvious because the plug is visible in the aft window. The cowl motion, however, is not as obvious because the cowl is hidden from view by the inlet sidewall. The end of the cowl actuator arm, however, becomes visible above the inlet sidewalls between the windows when the cowl is up (see figure 1b of the primary document). The model is injected into the tunnel and observed though several actuation sequences with two plug configurations over a range of unit freestream Reynolds number at a nominal freestream Mach number of 6. The framing rate and shutter speed of the camera were too slow to fully capture the dynamics of the unstart but did prove sufficient to identify inlet start and unstart. This series of tests indicated that the model was appropriately sized for this facility and identified operability limits required first to allow the inlet to start and second to force the unstart.

  18. Functional inhibition of aquaporin-3 with a gold-based compound induces blockage of cell proliferation.

    PubMed

    Serna, Ana; Galán-Cobo, Ana; Rodrigues, Claudia; Sánchez-Gomar, Ismael; Toledo-Aral, Juan José; Moura, Teresa F; Casini, Angela; Soveral, Graça; Echevarría, Miriam

    2014-11-01

    AQP3 has been correlated with higher transport of glycerol, increment of ATP content, and larger proliferation capacity. Recently, we described the gold(III) complex Auphen as a very selective and potent inhibitor of AQP3's glycerol permeability (Pgly ). Here we evaluated Auphen effect on the proliferation of various mammalian cell lines differing in AQP3 expression level: no expression (PC12), moderate (NIH/3T3) or high (A431) endogenous expression, cells stably expressing AQP3 (PC12-AQP3), and human HEK293T cells transiently transfected (HEK-AQP3) for AQP3 expression. Proliferation was evaluated in the absence or presence of Auphen (5 μM) by counting number of viable cells and analyzing 5-bromo-2'-deoxyuridine (BrdU) incorporation. Auphen reduced ≈50% the proliferation in A431 and PC12-AQP3, ≈15% in HEK-AQP3 and had no effect in PC12-wt and NIH/3T3. Strong arrest in the S-G2/M phases of the cell cycle, supported by analysis of cyclins (A, B1, D1, E) levels, was observed in AQP3-expressing cells treated with Auphen. Flow-cytometry of propidium iodide incorporation and measurements of mitochondrial dehydrogenases activity confirmed absence of cytotoxic effect of the drug. Functional studies evidenced ≈50% inhibition of A431 Pgly by Auphen, showing that the compound's antiproliferative effect correlates with its ability to inhibit AQP3 Pgly . Role of Cys-40 on AQP3 permeability blockage by Auphen was confirmed by analyzing the mutated protein (AQP3-Ser-40). Accordingly, cells transfected with mutated AQP3 gained resistance to the antiproliferative effect of Auphen. These results highlight an Auphen inhibitory effect on proliferation of cells expressing AQP3 and suggest a targeted therapeutic effect on carcinomas with large AQP3 expression. PMID:24676973

  19. Effects of ground water, slope stability, and seismic hazard on the stability of the South Fork Castle Creek blockage in the Mount St. Helens Area, Washington

    SciTech Connect

    Meyer, W.; Sabol, M.A.; Glicken, H.X.; Voight, B.

    1984-01-01

    South Fork Castle Creek was blocked by the debris avalanche that occurred during the May 18, 1980, eruption of Mount St. Helens, Washington. A lake formed behind the blockage, eventually reaching a volume of approximately 19,000 acre-feet prior to construction of a spillway - a volume sufficiently large to pose a flood hazard of unknown magnitude to downstream areas if the lake were to break out as a result of blockage failure. Breakout of lakes formed in a similar fashion is fairly common and several such events occurring in recent times have posed hazards around the world. Analyses of blockage stability included determining the effects of gravitational forces and horizontal forces induced by credible earthquakes from the Mount St. Helens seismic zone, which passes within several miles of the blockage. The blockage is stable at September 1983 water levels under static gravitational forces. If an earthquake with magnitude near 6.0 occurred with September 1983 water levels, movement on the order of 5 feet on both upstream and downstream parts of the blockage over much of its length could potentially occur. If the sliding blocks liquified, retrogressive failure could lead to lake breakout, but this is not considered to be probable. 24 refs., 25 figs., 5 tabs.

  20. Hydroacoustic mapping to define sedimentation rates and characterize lentic habitats in DeSoto Lake, DeSoto National Wildlife Refuge

    USGS Publications Warehouse

    Elliott, Caroline M.; Jacobson, Robert B.; Chojnacki, Kimberly A.

    2006-01-01

    Hydroacoustic tools were used to map depth, elevation, and substrate on DeSoto Lake in March 2006. DeSoto Lake, located on the DeSoto National Wildlife Refuge in Iowa and Nebraska, is one of the largest oxbow lakes of the Missouri River system. It is used by over 500,000 migratory birds each fall and spring and is also an important aquatic resource for anglers. Management concerns at the lake include the effects of erosion and sedimentation, aquatic vegetation establishment, shorebird habitat availability at different lake levels, and fish habitat structure. DeSoto Lake was cut off from the Missouri River in 1960, and the current mapping updates previous lower-resolution bathymetric maps created from lake surveys in 1967 and 1979. The new maps provide managers tools to assess aquatic habitats and provide a baseline for future monitoring of lake sedimentation and erosion.

  1. Induction of morphological and biochemical apoptosis following prolonged mitotic blockage by halichondrin B macrocyclic ketone analog E7389.

    PubMed

    Kuznetsov, Galina; Towle, Murray J; Cheng, Hongsheng; Kawamura, Takanori; TenDyke, Karen; Liu, Diana; Kishi, Yoshito; Yu, Melvin J; Littlefield, Bruce A

    2004-08-15

    E7389, a macrocyclic ketone analog of the marine natural product halichondrin B, currently is undergoing clinical trials for cancer. This fully synthetic agent exerts its highly potent in vitro and in vivo anticancer effects via tubulin-based antimitotic mechanisms, which are similar or identical to those of parental halichondrin B. In an attempt to understand the impressive potency of E7389 in animal models of human cancer, its ability to induce apoptosis following prolonged mitotic blockage was evaluated. Treatment of U937 human histiocytic lymphoma cells with E7389 led to time-dependent collection of cells in the G2-M phase of the cell cycle, beginning as early as 2 h and becoming maximal by 12 h. Increased numbers of hypodiploid events were seen beginning at 12 h, suggesting initiation of apoptosis after prolonged E7389-induced mitotic blockage. The identity of hypodiploid events as apoptotic cells under these conditions was confirmed by two additional morphologic criteria: green to orange/yellow shifts on acridine orange/ethidium bromide staining, and cell surface annexin V binding as assessed by flow cytometry. Several biochemical correlates of apoptosis also were seen following E7389 treatment, including phosphorylation of the antiapoptotic protein Bcl-2, cytochrome c release from mitochondria, proteolytic activation of caspase-3 and -9, and cleavage of the caspase-3 substrate poly(ADP-ribose) polymerase (PARP). In LNCaP human prostate cancer cells, treatment with E7389 also led to generation of hypodiploid cells, activation of caspase-3 and -9, and appearance of cleaved PARP, indicating that E7389 can activate cellular apoptosis pathways under anchorage-independent and -dependent cell culture conditions. These results show that prolonged mitotic blockage by E7389 can lead to apoptotic cell death of human cancer cells in vitro and can provide a mechanistic basis for the significant in vivo anticancer efficacy of E7389. PMID:15313917

  2. Submarine explosive activity and ocean noise generation at Monowai Volcano, Kermadec Arc: constraints from hydroacoustic T-waves

    NASA Astrophysics Data System (ADS)

    Grevemeyer, Ingo; Metz, Dirk; Watts, Anthony

    2016-04-01

    activity at Monowai volcano. Source-receiver distances were in the order of 70 km to 250 km. However, several events recorded on the local network were also detected at distances of several thousands of kilometres (up to ~ 16.000 km away) from the source, clearly indicating T-waves. We used the local network to automatically detect and locate T-wave bursts. Detecting and triggering was most effective when correcting the time of each OBS for a predicted travel time defined by the source-receiver distance. Using this approach we obtained appropriate data for automatic onset detection using long-term/short-term averages (LTA/STA). Out of the ~3500 events we could clearly associate more than 2000 events with Monowai. Eruptive activity at Monowai, however, was not evenly distributed in time but was highly clustered, indicating 13 to 15 major eruptive sequences. The sequences lasted from several hours to about 2 days. Periods of no detectable activity range from ~1 day to 70 days. The same approach was used to search the global database for the same time interval. Two Global Seismic Network (GSN) seismic stations and two hydroacoustic monitoring stations of the CTBTO provided T-waves from Monowai. We were able to record the same sequences, but the number of detected events was several times lower.

  3. T-waves from a slow earthquake: analysis of hydroacoustic data from the July 17, 2006 Jawa

    NASA Astrophysics Data System (ADS)

    Salzberg, D.; Pulli, J.

    2006-12-01

    The July 17, 2006 Jawa earthquake (Mw=7.7) was a `slow' earthquake, with little high frequency energy. The T-waves from this earthquake were recorded at the IMS hydroacoustic station at Diego Garcia. Comparisons between this T-wave and the T-waves for the Dec. 26, 2004 (Mw=9.3) and March 28, 2005 (Mw=8.7) Northern Sumatra earthquakes provides potential T-wave markers that can be useful for tsunami warning. First, the T-wave amplitude from the July 2006 event was small compared with that of the December 2004 and March 2005 events; peak amplitudes from the time series are about 100x smaller for the July 2006 event when compared to the other events. That presumably results from the lack of high frequency energy in the slow earthquake. Thus, we conclude the T-wave amplitude is not a robust indicator of tsunamigenisis. Another potential marker is the T-wave duration. The duration of the T- wave results from a combination of source duration and a broad seismic-to-acoustic conversion region. The latter can be calibrated by comparing the T-wave to that of an aftershock, as the aftershock can act as an empirical Green's function for the main shock. Therefore, the difference between the aftershock duration and mainshock duration gives approximate source durations. The mainshock T-wave duration for the July 2006 event was about 400 seconds compared with 80 seconds for the aftershock the next day, yielding a source duration of about 300 seconds. For comparison, the measured duration of the two northern Sumatra T-waves was 700 seconds (2004) and 260 seconds (2005). Thus, the T-wave duration may be an indicator of tsunamigenisis (or at least extended source duration). A final marker is based on the spectral content , represented by the spectral slope. We previously demonstrated that the spectral content of a T-wave results from attenuation from the solid-earth propagation path. Therefore, a shallow spectral slope (in log-amplitude space) indicates a shallow rupture, which is

  4. Hydroacoustic Evaluation of Overwintering Summer Steelhead Fallback and Kelt Passage at The Dalles Dam 2008-2009

    SciTech Connect

    Khan, Fenton; Johnson, Gary E.; Weiland, Mark A.

    2009-09-01

    This report presents the results of an evaluation of overwintering summer steelhead (Oncorhynchus mykiss) fallback and early out-migrating steelhead kelts downstream passage at The Dalles Dam (TDA) sluiceway and turbines during fall/winter 2008 and early spring 2009, respectively. The study was conducted by the Pacific Northwest National Laboratory (PNNL) for the U.S. Army Corps of Engineers, Portland District (USACE). Operating the sluiceway reduces the potential for hydropower production. However, this surface flow outlet may be the optimal non-turbine route for fallbacks in late fall after the sluiceway is typically closed for juvenile fish passage and for overwintering summer steelhead and kelt passage in the early spring before the start of the voluntary spill season. The goal of this study was to characterize adult steelhead spatial and temporal distributions and passage rates at the sluiceway and turbines, and their movements in front of the sluiceway at TDA to inform fisheries managers’ and engineers’ decision-making relative to sluiceway operations. The study periods were from November 1 to December 15, 2008 (45 days) and from March 1 to April 9, 2009 (40 days). The study objectives were to 1) estimate the number and distribution of overwintering summer steelhead fallbacks and kelt-sized acoustic targets passing into the sluiceway and turbines at TDA during the two study periods, respectively, and 2) assess the behavior of these fish in front of sluice entrances. We obtained fish passage data using fixed-location hydroacoustics and fish behavior data using acoustic imaging. For the overwintering summer steelhead, fallback occurred throughout the 45-day study period. We estimated that a total of 1790 ± 250 (95% confidence interval) summer steelhead targets passed through the powerhouse intakes and operating sluices during November 1 to December 15, 2008. Ninety five percent of these fish passed through the sluiceway. Therefore, without the sluiceway as

  5. Hydroacoustic Evaluation of Overwintering Summer Steelhead Fallback and Kelt Passage at The Dalles Dam, 2009-2010

    SciTech Connect

    Khan, Fenton; Johnson, Gary E.; Weiland, Mark A.

    2010-07-31

    This report presents the results of an evaluation of overwintering summer steelhead (Oncorhynchus mykiss) fallback and early out-migrating steelhead kelts downstream passage at The Dalles Dam (TDA) sluiceway and turbines during fall/winter 2009 through early spring 2010. The study was conducted by the Pacific Northwest National Laboratory (PNNL) for the U.S. Army Corps of Engineers, Portland District (USACE). The goal of this study was to characterize adult steelhead spatial and temporal distributions and passage rates at the sluiceway and turbines for fisheries managers and engineers to use in decision-making relative to sluiceway operations. The study was from November 1, 2009 to April 10, 2010. The study was divided into three study periods: Period 1, November 1 - December 15, 2009 for a fall/winter sluiceway and turbine study; Period 2, December 16, 2009 - February 28, 2010 for a turbine only study; Period 3, March 1 - April 10, 2010 for a spring sluiceway and turbine study. Sluiceway operations were scheduled to begin on March 1 for this study; however, because of an oil spill cleanup near the sluice outfall, sluiceway operations were delayed until March 8, 2010, therefore the spring study period did not commence until March 8. The study objectives were to (1) estimate the number and distribution of overwintering summer steelhead fallbacks and kelt-sized acoustic targets passing into the sluiceway and turbines at TDA between November 1 and December 15, 2009 and March 1 and April 10, 2010, and (2) estimate the numbers and distribution of adult steelhead and kelt-sized targets passing into turbine units between December 16, 2009 and February 28, 2010. We obtained fish passage data using fixed-location hydroacoustics. For Period 1, overwintering summer steelhead fallback occurred throughout the 45-day study period. A total of 879 {+-} 165 (95% CI) steelhead targets passed through the powerhouse and sluiceway during November 1 to December 15, 2009. Ninety two

  6. Kitaev models based on unitary quantum groupoids

    SciTech Connect

    Chang, Liang

    2014-04-15

    We establish a generalization of Kitaev models based on unitary quantum groupoids. In particular, when inputting a Kitaev-Kong quantum groupoid H{sub C}, we show that the ground state manifold of the generalized model is canonically isomorphic to that of the Levin-Wen model based on a unitary fusion category C. Therefore, the generalized Kitaev models provide realizations of the target space of the Turaev-Viro topological quantum field theory based on C.

  7. Experimental Investigation of the Flow Field in a Transonic, Axial Flow Compressor with Respect to the Development of Blockage and Loss

    NASA Technical Reports Server (NTRS)

    Suder, Kenneth L.

    1996-01-01

    A detailed experimental investigation to understand and quantify the development of loss and blockage in the flow field of a transonic, axial flow compressor rotor has been undertaken. Detailed laser anemometer measurements were acquired upstream, within, and downstream of a transonic, axial compressor rotor operating at design and off-design conditions. The rotor was operated at 100%, 85%, 80%, and 60% of design speed which provided inlet relative Mach numbers at the blade tip of 1.48, 1.26, 1.18, and 0.89 respectively. At design speed the blockage is evaluated ahead of the rotor passage shock, downstream of the rotor passage shock, and near the trailing edge of the blade row. The blockage is evaluated in the core flow area as well as in the casing endwall region. Similarly at pm speed conditions for the cases of (1) where the rotor passage shock is much weaker than that at design speed and (2) where there is no rotor passage shock, the blockage and loss are evaluated and compared to the results at design speed. Specifically, the impact of the rotor passage shock on the blockage and loss development, pertaining to both the shock/boundary layer interactions and the shock/tip clearance flow interactions, is discussed. In addition, the blockage evaluated from the experimental data is compared to (1) an existing correlation of blockage development which was based on computational results, and (2) computational results on a limited basis. The results indicate that for this rotor the blockage in the endwall region is 2-3 times that of the core flow region and the blockage in the core flow region more than doubles when the shock strength is sufficient to separate the suction surface boundary layer. The distribution of losses in the care flow region indicate that the total loss is primarily comprised of the shock loss when the shock strength is not sufficient to separate the suction surface boundary layer. However, when the shock strength is sufficient to separate the

  8. Gap junction blockage promotes cadmium-induced apoptosis in BRL 3A derived from Buffalo rat liver cells

    PubMed Central

    Hu, Di; Zou, Hui; Han, Tao; Xie, Junze; Dai, Nannan; Zhuo, Liling; Gu, Jianhong; Bian, Jianchun; Yuan, Yan; Liu, Xuezhong

    2016-01-01

    Gap junctions mediate direct communication between cells; however, toxicological cascade triggered by nonessential metals can abrogate cellular signaling mediated by gap junctions. Although cadmium (Cd) is known to induce apoptosis in organs and tissues, the mechanisms that underlie gap junction activity in Cd-induced apoptosis in BRL 3A rat liver cells has yet to be established. In this study, we showed that Cd treatment decreased the cell index (a measure of cellular electrical impedance) in BRL 3A cells. Mechanistically, we found that Cd exposure decreased expression of connexin 43 (Cx43), increased expression of p-Cx43 and elevated intracellular free Ca2+ concentration, corresponding to a decrease in gap junctional intercellular communication. Gap junction blockage pretreatment with 18β-glycyrrhizic acid (GA) promoted Cd-induced apoptosis, involving changes in expression of Bax, Bcl-2, caspase-3 and the mitochondrial transmembrane electrical potential (Δψm). Additionally, GA was found to enhance ERK and p38 activation during Cd-induced activation of mitogen-activated protein kinases, but had no significant effect on JNK activation. Our results indicated the apoptosis-related proteins and the ERK and p38 signaling pathways may participate in gap junction blockage promoting Cd-induced apoptosis in BRL 3A cells. PMID:27051341

  9. Mach 4 free-jet tunnel starting experiments for a hypersonic research engine model causing high blockage

    NASA Technical Reports Server (NTRS)

    Carson, G. T., Jr.; Midden, R. E.

    1976-01-01

    Tests of a full scale hypersonic research engine (HRE) were conducted in the hypersonic tunnel facility at Mach numbers of 5, 6, and 7. Since the HRE would cause a rather high blockage (48.83 percent of the nozzle area), subscale tests were conducted in various available small wind tunnels prior to the full scale tests to study the effects of model blockage on tunnel starting. The results of the Mach 4 subscale tests which utilized a model system at 0.0952 scale which simulated the HRE in the test section of the tunnel are presented. A satisfactory tunnel starting could not be achieved by varying the free jet length or diffuser size nor by inserting the model into the test stream after tunnel starting. However, the installation of a shroud around the HRE model allowed the tunnel to start with the model preset in the tunnel at a tunnel stagnation pressure to atmospheric exit pressure ratio of 13.4. The simulation of the discharge of instrumentation cooling water and the addition of test hardware at the aft end of the HRE model did not have a significant effect on the tunnel starting.

  10. Model-Based Prognostics of Hybrid Systems

    NASA Technical Reports Server (NTRS)

    Daigle, Matthew; Roychoudhury, Indranil; Bregon, Anibal

    2015-01-01

    Model-based prognostics has become a popular approach to solving the prognostics problem. However, almost all work has focused on prognostics of systems with continuous dynamics. In this paper, we extend the model-based prognostics framework to hybrid systems models that combine both continuous and discrete dynamics. In general, most systems are hybrid in nature, including those that combine physical processes with software. We generalize the model-based prognostics formulation to hybrid systems, and describe the challenges involved. We present a general approach for modeling hybrid systems, and overview methods for solving estimation and prediction in hybrid systems. As a case study, we consider the problem of conflict (i.e., loss of separation) prediction in the National Airspace System, in which the aircraft models are hybrid dynamical systems.

  11. Testing Strategies for Model-Based Development

    NASA Technical Reports Server (NTRS)

    Heimdahl, Mats P. E.; Whalen, Mike; Rajan, Ajitha; Miller, Steven P.

    2006-01-01

    This report presents an approach for testing artifacts generated in a model-based development process. This approach divides the traditional testing process into two parts: requirements-based testing (validation testing) which determines whether the model implements the high-level requirements and model-based testing (conformance testing) which determines whether the code generated from a model is behaviorally equivalent to the model. The goals of the two processes differ significantly and this report explores suitable testing metrics and automation strategies for each. To support requirements-based testing, we define novel objective requirements coverage metrics similar to existing specification and code coverage metrics. For model-based testing, we briefly describe automation strategies and examine the fault-finding capability of different structural coverage metrics using tests automatically generated from the model.

  12. Model-based satellite acquisition and tracking

    NASA Technical Reports Server (NTRS)

    Casasent, David; Lee, Andrew J.

    1988-01-01

    A model-based optical processor is introduced for the acquisition and tracking of a satellite in close proximity to an imaging sensor of a space robot. The type of satellite is known in advance, and a model of the satellite (which exists from its design) is used in this task. The model base is used to generate multiple smart filters of the various parts of the satellite, which are used in a symbolic multi-filter optical correlator. The output from the correlator is then treated as a symbolic description of the object, which is operated upon by an optical inference processor to determine the position and orientation of the satellite and to track it as a function of time. The knowledge and model base also serves to generate the rules used by the inference machine. The inference machine allows for feedback to optical correlators or feature extractors to locate the individual parts of the satellite and their orientations.

  13. Multimode model based defect characterization in composites

    NASA Astrophysics Data System (ADS)

    Roberts, R.; Holland, S.; Gregory, E.

    2016-02-01

    A newly-initiated research program for model-based defect characterization in CFRP composites is summarized. The work utilizes computational models of the interaction of NDE probing energy fields (ultrasound and thermography), to determine 1) the measured signal dependence on material and defect properties (forward problem), and 2) an assessment of performance-critical defect properties from analysis of measured NDE signals (inverse problem). Work is reported on model implementation for inspection of CFRP laminates containing delamination and porosity. Forward predictions of measurement response are presented, as well as examples of model-based inversion of measured data for the estimation of defect parameters.

  14. Model-based internal wave processing

    SciTech Connect

    Candy, J.V.; Chambers, D.H.

    1995-06-09

    A model-based approach is proposed to solve the oceanic internal wave signal processing problem that is based on state-space representations of the normal-mode vertical velocity and plane wave horizontal velocity propagation models. It is shown that these representations can be utilized to spatially propagate the modal (dept) vertical velocity functions given the basic parameters (wave numbers, Brunt-Vaisala frequency profile etc.) developed from the solution of the associated boundary value problem as well as the horizontal velocity components. Based on this framework, investigations are made of model-based solutions to the signal enhancement problem for internal waves.

  15. Model-Based Inquiries in Chemistry

    ERIC Educational Resources Information Center

    Khan, Samia

    2007-01-01

    In this paper, instructional strategies for sustaining model-based inquiry in an undergraduate chemistry class were analyzed through data collected from classroom observations, a student survey, and in-depth problem-solving sessions with the instructor and students. Analysis of teacher-student interactions revealed a cyclical pattern in which…

  16. What's Missing in Model-Based Teaching

    ERIC Educational Resources Information Center

    Khan, Samia

    2011-01-01

    In this study, the author investigated how four science teachers employed model-based teaching (MBT) over a 1-year period. The purpose of the research was to develop a baseline of the fundamental and specific dimensions of MBT that are present and absent in science teaching. Teacher interviews, classroom observations, and pre and post-student…

  17. Sandboxes for Model-Based Inquiry

    ERIC Educational Resources Information Center

    Brady, Corey; Holbert, Nathan; Soylu, Firat; Novak, Michael; Wilensky, Uri

    2015-01-01

    In this article, we introduce a class of constructionist learning environments that we call "Emergent Systems Sandboxes" ("ESSs"), which have served as a centerpiece of our recent work in developing curriculum to support scalable model-based learning in classroom settings. ESSs are a carefully specified form of virtual…

  18. Hydroacoustic detection of dumped ammunition in the Ocean with multibeam snippet backscatter analyses. A case study from the 'Kolberger Heide' ammunition dump site (Baltic Sea, Germany)

    NASA Astrophysics Data System (ADS)

    Kunde, Tina; Schneider von Deimling, Jens

    2016-04-01

    Dumped ammunition in the sea is a matter of great concern in terms of safe navigation and environmental threads. Because corrosion of the dumped ammunition's hull is ongoing, future contamination of the ambient water by their toxic interior is likely to occur. The location of such dump sites is approximately known from historical research and ship log book analyses. Subsequent remote sensing of ammunition dumping sites (e.g. mines) on the seafloor is preferentially performed with hydro-acoustic methods such as high resolution towed side scan or by the sophisticated synthetic aperture sonar approach with autonomous underwater vehicles. However, these are time consuming and expensive procedures, while determining the precise position of individual mines remains a challenging task. To mitigate these shortcomings we suggest using ship-born high-frequency multibeam sonar in shallow water to address the task of mine detection and precise localization on the seabed. Multibeam sonar systems have improved their potential in regard to backscatter analyses significantly over the past years and nowadays present fast and accurate tools for shallow water surveying to (1) detect mines in multibeam snippet backscatter data (2) determine their precise location with high accuracy intertial navigation systems. A case study was performed at the prominent ammunition dumping site 'Kolberger Heide' (Baltic Sea, Germany) in the year 2014 using a modern hydro-acoustic multibeam echosounder system with 200-400 kHz (KONGSBERG EM2040c). With an average water depth of not even 20 m and the proximity to the shore line and dense waterways, this investigated area requires permanent navigational care. Previously, the study area was surveyed by the Navy with the very sophisticated HUGIN AUV equipped with a synthetic aperture sonar with best resolution by current technology. Following an evaluation of the collected data, various ammunition bodies on the sea floor could be clearly detected. Analyses

  19. Buoyancy and blockage effects on transient laminar opposing mixed convection heat transfer from two horizontal confined isothermal cylinder in tandem

    NASA Astrophysics Data System (ADS)

    Martínez-Suástegui, Lorenzo; Salcedo, Erick; Cajas, Juan; Treviño, César

    2015-11-01

    Transient mixed convection in a laminar cross-flow from two isothermal cylinders in tandem arrangement confined inside a vertical channel is studied numerically using the vorticity-stream function formulation of the unsteady two-dimensional Navier-Stokes and energy equations. Numerical experiments are performed for a Reynolds number based on cylinder diameter of Re = 200, Prandtl number of Pr = 7, blockage ratio of D/H = 0.2, a pitch-to-diameter ratio of L/D = 2, and several values of buoyancy strength or Richardson number Ri = Gr/Re2. The results reported herein demonstrate how the wall confinement, interference effects and opposing buoyancy affect the flow structure and heat transfer characteristics of the cylinder array. This research was supported by the Consejo Nacional de Ciencia y Tecnología (CONACYT), Grant number 167474 and by the Secretaría de Investigación y Posgrado del IPN, Grant number SIP 20141309.

  20. Blockage of VIP during mouse embryogenesis modifies adult behavior and results in permanent changes in brain chemistry.

    PubMed

    Hill, Joanna M; Hauser, Janet M; Sheppard, Lia M; Abebe, Daniel; Spivak-Pohis, Irit; Kushnir, Michal; Deitch, Iris; Gozes, Illana

    2007-01-01

    Vasoactive intestinal peptide (VIP) regulates growth and development during the early postimplantation period of mouse embryogenesis. Blockage of VIP with a VIP antagonist during this period results in growth restriction, microcephaly, and developmental delays. Similar treatment of neonatal rodents also causes developmental delays and impaired diurnal rhythms, and the adult brains of these animals exhibit neuronal dystrophy and increased VIP binding. These data suggest that blockage of VIP during the development of the nervous system can result in permanent changes to the brain. In the current study, pregnant mice were treated with a VIP antagonist during embryonic days 8 through 10. The adult male offspring were examined in tests of novelty, paired activity, and social recognition. Brain tissue was examined for several measures of chemistry and gene expression of VIP and related compounds. Glial cells from the cortex of treated newborn mice were plated with neurons and examined for VIP binding and their ability to enhance neuronal survival. Treated adult male mice exhibited increased anxiety-like behavior and deficits in social behavior. Brain tissue exhibited regionally specific changes in VIP chemistry and a trend toward increased gene expression of VIP and related compounds that reached statistical significance in the VIP receptor, VPAC-1, in the female cortex. When compared to control astrocytes, astrocytes from treated cerebral cortex produced further increases in neuronal survival with excess synaptic connections and reduced VIP binding. In conclusion, impaired VIP activity during mouse embryogenesis resulted in permanent changes to both adult brain chemistry/cell biology and behavior with aspects of autism-like social deficits. PMID:17726225

  1. PWR FLECHT SEASET 21-rod-bundle flow-blockage task: data and analysis report. NRC/EPRI/Westinghouse report No. 11, main report and appendices A-J

    SciTech Connect

    Loftus, M.J.; Hochreiter, L.E.; Lee, N.; McGuire, M.F.; Wenzel, A.H.; Valkovic, M.M.

    1982-09-01

    This report presents data and limited analysis from the 21-Rod Bundle Flow Blockage Task of the Full-Length Emergency Cooling Heat Transfer Separate Effects and Systems Effects Test Program (FLECHT SEASET). The tests consisted of forced and gravity reflooding tests utilizing electrical heater rods with a cosine axial power profile to simulate PWR nuclear core fuel rod arrays. Steam cooling and hydraulic characteristics tests were also conducted. These tests were utilized to determine effects of various flow blockage configurations (shapes and distributions) on reflooding behavior, to aid in development/assessment of computational models in predicting reflooding behavior of flow blockage configurations, and to screen flow blockage configurations for future 163-rod flow blockage bundle tests.

  2. Operation Dominic, Shot Sword Fish. Project Officer's report - Project 1. 3b. Effects of an underwater nuclear explosion on hydroacoustic systems

    SciTech Connect

    McMillan, T.; La Houssaye, W.P.; Johnson, C.T.

    1985-09-01

    The objectives of Project 1.2 were to determine and evaluate the effects of an underwater nuclear explosion on the operational capabilities of shipboard sonar and other types of hydroacoustic systems. Project 1.3b included all measurements at ranges greater than 10 nautical miles and the results of these measurements constitute the subject of this report. This report concerns the effects of the underwater nuclear explosion, Sword Fish, on: (a) Long-range active detection systems at the first convergence zone (25 to 30 miles); (b) Passive shipboard or submarine sonars at a few hundred miles; and (c) Long-range passive detection and surveillance at Sound Surveillance System (SOSUS) and Missile Impact Locating System (MILS) stations at several hundred to several thousand miles. A submarine station at the first convergence zone and five shipboard stations at ranges from 200 miles to 5,000 miles recorded signals from hydrophones suspended at various depths to approximately 2,000 feet. Submarines on other assignments recorded signals on standard submarine sonar equipment on a not-to interfere basis. SOSUS and MILS stations operated normally during the period and also made special magnetic-tape and strip-chart recordings of signals from single hydrophones from before burst time to several hours after burst.

  3. Efficient Model-Based Diagnosis Engine

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Vatan, Farrokh; Barrett, Anthony; James, Mark; Mackey, Ryan; Williams, Colin

    2009-01-01

    An efficient diagnosis engine - a combination of mathematical models and algorithms - has been developed for identifying faulty components in a possibly complex engineering system. This model-based diagnosis engine embodies a twofold approach to reducing, relative to prior model-based diagnosis engines, the amount of computation needed to perform a thorough, accurate diagnosis. The first part of the approach involves a reconstruction of the general diagnostic engine to reduce the complexity of the mathematical-model calculations and of the software needed to perform them. The second part of the approach involves algorithms for computing a minimal diagnosis (the term "minimal diagnosis" is defined below). A somewhat lengthy background discussion is prerequisite to a meaningful summary of the innovative aspects of the present efficient model-based diagnosis engine. In model-based diagnosis, the function of each component and the relationships among all the components of the engineering system to be diagnosed are represented as a logical system denoted the system description (SD). Hence, the expected normal behavior of the engineering system is the set of logical consequences of the SD. Faulty components lead to inconsistencies between the observed behaviors of the system and the SD (see figure). Diagnosis - the task of finding faulty components - is reduced to finding those components, the abnormalities of which could explain all the inconsistencies. The solution of the diagnosis problem should be a minimal diagnosis, which is a minimal set of faulty components. A minimal diagnosis stands in contradistinction to the trivial solution, in which all components are deemed to be faulty, and which, therefore, always explains all inconsistencies.

  4. Systems Engineering Interfaces: A Model Based Approach

    NASA Technical Reports Server (NTRS)

    Fosse, Elyse; Delp, Christopher

    2013-01-01

    Currently: Ops Rev developed and maintains a framework that includes interface-specific language, patterns, and Viewpoints. Ops Rev implements the framework to design MOS 2.0 and its 5 Mission Services. Implementation de-couples interfaces and instances of interaction Future: A Mission MOSE implements the approach and uses the model based artifacts for reviews. The framework extends further into the ground data layers and provides a unified methodology.

  5. MODEL-BASED IMAGE RECONSTRUCTION FOR MRI

    PubMed Central

    Fessler, Jeffrey A.

    2010-01-01

    Magnetic resonance imaging (MRI) is a sophisticated and versatile medical imaging modality. Traditionally, MR images are reconstructed from the raw measurements by a simple inverse 2D or 3D fast Fourier transform (FFT). However, there are a growing number of MRI applications where a simple inverse FFT is inadequate, e.g., due to non-Cartesian sampling patterns, non-Fourier physical effects, nonlinear magnetic fields, or deliberate under-sampling to reduce scan times. Such considerations have led to increasing interest in methods for model-based image reconstruction in MRI. PMID:21135916

  6. Model-based multiple patterning layout decomposition

    NASA Astrophysics Data System (ADS)

    Guo, Daifeng; Tian, Haitong; Du, Yuelin; Wong, Martin D. F.

    2015-10-01

    As one of the most promising next generation lithography technologies, multiple patterning lithography (MPL) plays an important role in the attempts to keep in pace with 10 nm technology node and beyond. With feature size keeps shrinking, it has become impossible to print dense layouts within one single exposure. As a result, MPL such as double patterning lithography (DPL) and triple patterning lithography (TPL) has been widely adopted. There is a large volume of literature on DPL/TPL layout decomposition, and the current approach is to formulate the problem as a classical graph-coloring problem: Layout features (polygons) are represented by vertices in a graph G and there is an edge between two vertices if and only if the distance between the two corresponding features are less than a minimum distance threshold value dmin. The problem is to color the vertices of G using k colors (k = 2 for DPL, k = 3 for TPL) such that no two vertices connected by an edge are given the same color. This is a rule-based approach, which impose a geometric distance as a minimum constraint to simply decompose polygons within the distance into different masks. It is not desired in practice because this criteria cannot completely capture the behavior of the optics. For example, it lacks of sufficient information such as the optical source characteristics and the effects between the polygons outside the minimum distance. To remedy the deficiency, a model-based layout decomposition approach to make the decomposition criteria base on simulation results was first introduced at SPIE 2013.1 However, the algorithm1 is based on simplified assumption on the optical simulation model and therefore its usage on real layouts is limited. Recently AMSL2 also proposed a model-based approach to layout decomposition by iteratively simulating the layout, which requires excessive computational resource and may lead to sub-optimal solutions. The approach2 also potentially generates too many stiches. In this

  7. Vector space model based on semantic relatedness

    NASA Astrophysics Data System (ADS)

    Bondarchuk, Dmitry; Timofeeva, Galina

    2015-11-01

    Most of data-mining methods are based on the vector space model of knowledge representation. The vector space model uses the frequency of a term in order to determine its relevance in a document. Terms can be similar by semantic meaning but be lexicographically different ones, so the classification based on the frequency of terms does not give desired results in some subject areas such as the vacancies selection. The modified vector space model based on the semantic relatedness is suggested for data-mining in this area. Evaluation results show that the proposed algorithm is better then one based on the standard vector space model.

  8. Model-based Tomographic Reconstruction Literature Search

    SciTech Connect

    Chambers, D H; Lehman, S K

    2005-11-30

    In the process of preparing a proposal for internal research funding, a literature search was conducted on the subject of model-based tomographic reconstruction (MBTR). The purpose of the search was to ensure that the proposed research would not replicate any previous work. We found that the overwhelming majority of work on MBTR which used parameterized models of the object was theoretical in nature. Only three researchers had applied the technique to actual data. In this note, we summarize the findings of the literature search.

  9. Model-based vision using geometric hashing

    NASA Astrophysics Data System (ADS)

    Akerman, Alexander, III; Patton, Ronald

    1991-04-01

    The Geometric Hashing technique developed by the NYU Courant Institute has been applied to various automatic target recognition applications. In particular, I-MATH has extended the hashing algorithm to perform automatic target recognition ofsynthetic aperture radar (SAR) imagery. For this application, the hashing is performed upon the geometric locations of dominant scatterers. In addition to being a robust model-based matching algorithm -- invariant under translation, scale, and 3D rotations of the target -- hashing is of particular utility because it can still perform effective matching when the target is partially obscured. Moreover, hashing is very amenable to a SIMD parallel processing architecture, and thus potentially realtime implementable.

  10. Model-Based Fault Tolerant Control

    NASA Technical Reports Server (NTRS)

    Kumar, Aditya; Viassolo, Daniel

    2008-01-01

    The Model Based Fault Tolerant Control (MBFTC) task was conducted under the NASA Aviation Safety and Security Program. The goal of MBFTC is to develop and demonstrate real-time strategies to diagnose and accommodate anomalous aircraft engine events such as sensor faults, actuator faults, or turbine gas-path component damage that can lead to in-flight shutdowns, aborted take offs, asymmetric thrust/loss of thrust control, or engine surge/stall events. A suite of model-based fault detection algorithms were developed and evaluated. Based on the performance and maturity of the developed algorithms two approaches were selected for further analysis: (i) multiple-hypothesis testing, and (ii) neural networks; both used residuals from an Extended Kalman Filter to detect the occurrence of the selected faults. A simple fusion algorithm was implemented to combine the results from each algorithm to obtain an overall estimate of the identified fault type and magnitude. The identification of the fault type and magnitude enabled the use of an online fault accommodation strategy to correct for the adverse impact of these faults on engine operability thereby enabling continued engine operation in the presence of these faults. The performance of the fault detection and accommodation algorithm was extensively tested in a simulation environment.

  11. Sandboxes for Model-Based Inquiry

    NASA Astrophysics Data System (ADS)

    Brady, Corey; Holbert, Nathan; Soylu, Firat; Novak, Michael; Wilensky, Uri

    2015-04-01

    In this article, we introduce a class of constructionist learning environments that we call Emergent Systems Sandboxes ( ESSs), which have served as a centerpiece of our recent work in developing curriculum to support scalable model-based learning in classroom settings. ESSs are a carefully specified form of virtual construction environment that support students in creating, exploring, and sharing computational models of dynamic systems that exhibit emergent phenomena. They provide learners with "entity"-level construction primitives that reflect an underlying scientific model. These primitives can be directly "painted" into a sandbox space, where they can then be combined, arranged, and manipulated to construct complex systems and explore the emergent properties of those systems. We argue that ESSs offer a means of addressing some of the key barriers to adopting rich, constructionist model-based inquiry approaches in science classrooms at scale. Situating the ESS in a large-scale science modeling curriculum we are implementing across the USA, we describe how the unique "entity-level" primitive design of an ESS facilitates knowledge system refinement at both an individual and social level, we describe how it supports flexible modeling practices by providing both continuous and discrete modes of executability, and we illustrate how it offers students a variety of opportunities for validating their qualitative understandings of emergent systems as they develop.

  12. Blockage of Galectin-receptor Interactions by α-lactose Exacerbates Plasmodium berghei-induced Pulmonary Immunopathology.

    PubMed

    Liu, Jinfeng; Huang, Shiguang; Su, Xin-Zhuan; Song, Jianping; Lu, Fangli

    2016-01-01

    Malaria-associated acute lung injury (ALI) is a frequent complication of severe malaria that is often caused by "excessive" immune responses. To better understand the mechanism of ALI in malaria infection, here we investigated the roles of galectin (Gal)-1, 3, 8, 9 and the receptors of Gal-9 (Tim-3, CD44, CD137, and PDI) in malaria-induced ALI. We injected alpha (α)-lactose into mice-infected with Plasmodium berghei ANKA (PbANKA) to block galectins and found significantly elevated total proteins in bronchoalveolar lavage fluid, higher parasitemia and tissue parasite burden, and increased numbers of CD68(+) alveolar macrophages as well as apoptotic cells in the lungs after blockage. Additionally, mRNA levels of Gal-9, Tim-3, CD44, CD137, and PDI were significantly increased in the lungs at day 5 after infection, and the levels of CD137, IFN-α, IFN-β, IFN-γ, IL-4, and IL-10 in the lungs were also increased after α-lactose treatment. Similarly, the levels of Gal-9, Tim-3, IFN-α, IFN-β, IFN-γ, and IL-10 were all significantly increased in murine peritoneal macrophages co-cultured with PbANKA-infected red blood cells in vitro; but only IFN-α and IFN-β were significantly increased after α-lactose treatment. Our data indicate that Gal-9 interaction with its multiple receptors play an important role in murine malaria-associated ALI. PMID:27554340

  13. On the preventive management of sediment-related sewer blockages: a combined maintenance and routing optimization approach.

    PubMed

    Fontecha, John E; Akhavan-Tabatabaei, Raha; Duque, Daniel; Medaglia, Andrés L; Torres, María N; Rodríguez, Juan Pablo

    2016-01-01

    In this work we tackle the problem of planning and scheduling preventive maintenance (PM) of sediment-related sewer blockages in a set of geographically distributed sites that are subject to non-deterministic failures. To solve the problem, we extend a combined maintenance and routing (CMR) optimization approach which is a procedure based on two components: (a) first a maintenance model is used to determine the optimal time to perform PM operations for each site and second (b) a mixed integer program-based split procedure is proposed to route a set of crews (e.g., sewer cleaners, vehicles equipped with winches or rods and dump trucks) in order to perform PM operations at a near-optimal minimum expected cost. We applied the proposed CMR optimization approach to two (out of five) operative zones in the city of Bogotá (Colombia), where more than 100 maintenance operations per zone must be scheduled on a weekly basis. Comparing the CMR against the current maintenance plan, we obtained more than 50% of cost savings in 90% of the sites. PMID:27438233

  14. Blockage by gibberellic Acid of phytochrome effects on growth, auxin responses, and flavonoid synthesis in etiolated pea internodes.

    PubMed

    Russell, D W; Galston, A W

    1969-09-01

    Red light inhibits the growth of etiolated pea internodes, causes a shift toward higher indoleacetic acid (IAA) concentrations in the IAA dose-response curve of excised sections, and promotes the synthesis in intact internodes of kaempferol-3-triglucoside. Gibberellic acid (GA(3)) prevents all 3 effects, the first effect substantially and the last 2 completely. This suggests GA(3) blockage of an early or basic event initiated by the active form of phytochrome. The red light-induced shift in the IAA dose-response curve of excised sections is consistent with a light-induced increase in the activity of an IAA destruction system, since the magnitude of the red light inhibition varied with IAA concentration. The red light and GA(3) effects on growth and on flavonoid synthesis are consistent with the view that phytochrome may control growth by regulating the synthesis of phenolic compounds which act as cofactors in an IAA-oxidase system. GA(3) reversal of the red light-induced shift in the IAA dose-response curve involves both growth promotion and inhibition by GA(3) at different IAA concentrations and this, together with the GA(3) reversal of light-induced flavonoid synthesis, supports the suggested regulatory role of phenolic compounds in growth. PMID:16657193

  15. Theaflavins suppress tumor growth and metastasis via the blockage of the STAT3 pathway in hepatocellular carcinoma

    PubMed Central

    Shao, Jianping; Meng, Qingyan; Li, Yongyuan

    2016-01-01

    Theaflavins, the major black tea polyphenols, have been reported to exhibit promising antitumor activities in several human cancers. However, the role of theaflavins in hepatocellular carcinoma (HCC) is still unknown. In this study, we found that theaflavins could significantly inhibit proliferation, migration, and invasion, and induce apoptosis in HCC cells in vitro. Furthermore, we found that theaflavins inhibited the growth and metastasis of HCC in an orthotopic model and a lung metastasis model. Immunohistochemical analyses and terminal deoxynucleotidyl transferase dUTP nick end-labeling assays showed that theaflavins could suppress proliferation and induce apoptosis in vivo. Theaflavins also suppressed constitutive and inducible signal transducer and activator of transcription 3 (STAT3) phosphorylation. The downstream proteins regulated by STAT3, including the antiapoptotic proteins (Bcl-2 and Survivin) and the invasion-related proteins (MMP-2, MMP-9), were also downregulated after theaflavins treatment. Theaflavins induced apoptosis by activating the caspase pathway. Together, our results suggest that theaflavins suppress the growth and metastasis of human HCC through the blockage of the STAT3 pathway, and thus may act as potential therapeutic agents for HCC. PMID:27478384

  16. Unifying Model-Based and Reactive Programming within a Model-Based Executive

    NASA Technical Reports Server (NTRS)

    Williams, Brian C.; Gupta, Vineet; Norvig, Peter (Technical Monitor)

    1999-01-01

    Real-time, model-based, deduction has recently emerged as a vital component in AI's tool box for developing highly autonomous reactive systems. Yet one of the current hurdles towards developing model-based reactive systems is the number of methods simultaneously employed, and their corresponding melange of programming and modeling languages. This paper offers an important step towards unification. We introduce RMPL, a rich modeling language that combines probabilistic, constraint-based modeling with reactive programming constructs, while offering a simple semantics in terms of hidden state Markov processes. We introduce probabilistic, hierarchical constraint automata (PHCA), which allow Markov processes to be expressed in a compact representation that preserves the modularity of RMPL programs. Finally, a model-based executive, called Reactive Burton is described that exploits this compact encoding to perform efficIent simulation, belief state update and control sequence generation.

  17. Breaking into the Plate: Seismic and Hydroacoustic Analysis of a 7.6 Mw Oceanic Fracture Zone Earthquake Adjacent to the Central Indian Ridge Plate Boundary

    NASA Astrophysics Data System (ADS)

    Bohnenstiehl, D. R.; Tolstoy, M.; Chapp, E.

    2003-12-01

    Where oceanic spreading segments are offset laterally from one another, the differential motion of the plates is accommodated by strike-slip motion along ridge-perpendicular transform faults. Off-axis from the ridge-transform intersection, no differential motion is require, and the fracture zone trace is thought to be inactive except where reactivated by intra-plate stresses. On 15 July 2003, an earthquake with a magnitude of 7.6 Mw occurred near the northern Central Indian Ridge (CIR), the divergent boundary separating the Somalian plate from the Indian and Australian plates. The size of this event places it within the 99th quantile of magnitude for shallow (< 40 km depth) strike-slip events (null axis plunge >45 deg) within the global Harvard CMT catalog. The earthquake's epicenter is near 2.5 deg S, 68.33 deg E, where the CIR is marked by a series of short (<100 km long) right-stepping transforms that offset the northwest trending spreading segments (20 mm/yr). Seismic signals associated with the mainshock and its largest aftershocks were recorded well by land-based seismic networks. Regional seismic phases (Pn, Sn), as well oceanic T-waves, where also recorded at an IMS hydroacoustic station to the north of the Diego Garcia atoll. T-wave signals recorded at Diego Garcia were cross correlated to determine accurate travel time differences. These traveltime differences were used in a plane wave fitting inversion to determine the horizontal slowness components and estimate the back azimuth to the epicenter. Aftershock locations are derived using the azimuthal information and Pn-T traveltime differences. Together, the seismically- and hydroacoustically-derived epicenters show a linear band of aftershocks extending more than 200 km along the off-axis trace of a right stepping transform. We interpret these aftershock events as delineating the length of the mainshock rupture. As the well-constrain hypocenter of the mainshock lies near the western edge of this

  18. Application of hydroacoustics to investigate the distribution, diel movement, and abundance of fish on Zhubi Reef, Nansha Islands, South China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Chen, Guobao; Chen, Zuozhi; Qiu, Yongsong; Xiong, Dan

    2016-01-01

    A combination of traditional fish sampling methods (hand-line and gill net) and modern hydroacoustic techniques were used to study fish community structure, distribution, and diel movements of fish on Zhubi Reef to enhance understanding of the ecosystem. We collected 126 individuals from 29 species, 20 genera, 17 families, three orders, and two classes using traditional gear. Perciforms were the dominant group in terms of species richness and biomass. The acoustic data indicated that very small (target strength [TS], dB) <-60 dB) and small (-60 dB≤TS<-45 dB) fish contributed the most to abundance and species richness on the coral reef, and that the proportion of medium-sized (-45 dB≤TS<-35 dB) and large-sized (-35 dB≤TS) fish increased gradually as depth increased. The single-target detection method revealed two distinct size classes during the day in the 12-16 and 16-20-m layers. One group consisted of very small-sized fish (TS<-60 dB) and the other consisted of medium and large-sized fish (TS>-55 dB). The number of single-target detections was significantly higher during the night than during the day (P<0.05). The singletarget TS frequency distribution during the day was significantly diff erent than during the night at depths of 4-8, 8-12, 12-16, and 16-20 m. Significant diff erences were observed among the 4-8, 8-12, 12-16, and 16-20-m-depth layers during day and night. Diel vertical movement was evidenced as fish began to spread and move upward just before sunset and began to assemble and descend shortly (15 min) after sunrise.

  19. Time-Clustering Behavior of Spreading-Center Seismicity Between 15-35 N on the Mid-Atlantic Ridge: Observations from Hydroacoustic Monitoring

    NASA Astrophysics Data System (ADS)

    Bohnenstiehl, D. R.; Tolstoy, M.; Smith, D. K.; Fox, C. G.; Dziak, R. P.

    2002-12-01

    An earthquake catalog derived from the detection of seismically-generated Tertiary (T) waves is used to study the time-clustering behavior of moderate-size (> 3.0 M) earthquakes along the north-central Mid-Atlantic Ridge. Because T-waves propagate efficiently within the ocean's sound channel, these data represent a significant improvement relative to the detection capabilities of land-based seismic stations. In addition, hydroacoustic monitoring overcomes many of the spatial and temporal limitations associated with ocean-bottom seismometer data, with the existing array being deployed continuously between 15-35 degrees N during the period February 1999-Februrary 2001.Within this region, the distribution of inter-event times is consistent with a non-random clustered process, with a coefficient of variation greater than 1.0. The clustered behavior is power-law in nature with temporal fluctuations characterized by a power spectral density that decays as 1/fα . Using Allan Factor analysis, α is found to range from 0.12-0.55 for different regions of the spreading axis. This scaling is negligible at time scales less than 3.5 x 103 s, and earthquake occurrence becomes less clustered (smaller α ) as increasing size thresholds are applied to the catalog. The highest degrees of clustering are associated temporally with large mainshock-aftershock sequences; however, some swarm-like activity also is evident. The distribution of acoustic magnitudes, or source levels, is consistent with a power-law size-frequency scaling for earthquakes. Although such behavior has been linked closely to the fractal nature of the underlying fault population in other environments, power-law fault size distributions have not been widely observed in the mid-ocean ridge setting.

  20. Establishing a Dynamic Database of Blue and Fin Whale Locations from Recordings at the IMS CTBTO hydro-acoustic network. The Baleakanta Project

    NASA Astrophysics Data System (ADS)

    Le Bras, R. J.; Kuzma, H.

    2013-12-01

    Falling as they do into the frequency range of continuously recording hydrophones (15-100Hz), blue and fin whale songs are a significant source of noise on the hydro-acoustic monitoring array of the International Monitoring System (IMS) of the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO). One researcher's noise, however, can be a very interesting signal in another field of study. The aim of the Baleakanta Project (www.baleakanta.org) is to flag and catalogue these songs, using the azimuth and slowness of the signal measured at multiple hydrophones to solve for the approximate location of singing whales. Applying techniques borrowed from human speaker identification, it may even be possible to recognize the songs of particular individuals. The result will be a dynamic database of whale locations and songs with known individuals noted. This database will be of great value to marine biologists studying cetaceans, as there is no existing dataset which spans the globe over many years (more than 15 years of data have been collected by the IMS). Current whale song datasets from other sources are limited to detections made on small, temporary listening devices. The IMS song catalogue will make it possible to study at least some aspects of the global migration patterns of whales, changes in their songs over time, and the habits of individuals. It is believed that about 10 blue whale 'cultures' exist with distinct vocal patterns; the IMS song catalogue will test that number. Results and a subset of the database (delayed in time to mitigate worries over whaling and harassment of the animals) will be released over the web. A traveling museum exhibit is planned which will not only educate the public about whale songs, but will also make the CTBTO and its achievements more widely known. As a testament to the public's enduring fascination with whales, initial funding for this project has been crowd-sourced through an internet campaign.

  1. Lander based hydroacoustic monitoring of marine single bubble releases in Eckernförde Bay utilizing the multibeam based GasQuant II system.

    NASA Astrophysics Data System (ADS)

    Urban, Peter; Schneider von Deimling, Jens; Greinert, Jens

    2015-04-01

    The GEOMAR Helmholtz Centre for Ocean Research Kiel is currently developing a Imagenex Delta T based lander system for monitoring and quantifying marine gas release (bubbles). The GasQuant II is built as the successor of the GasQuant I system (Greinert, 2008), that has been successfully used for monitoring tempo-spatial variability of gas release in the past (Schneider von Deimling et al., 2010). The new system is lightweight (40 kg), energy efficient, flexible to use and built for ROV deployment with autonomous operation of up to three days. A prototype has been successfully deployed in Eckernförde Bay during the R/V ALKOR cruise AL447 in October/November 2014 to monitor the tempo-spatial variability of gas bubble seepage and to detect a possible correlation with tidal variations. Two deployments, one in forward- and one in upward looking mode, reveal extensive but scattered single bubble releases rather than distinct and more continuous sources. While these releases are difficult to detect in forward looking mode, they can unambiguously be detected in the upward looking mode even for minor gas releases, bubble rising speeds can be determined. Greinert, J., 2008. Monitoring temporal variability of bubble release at seeps: The hydroacoustic swath system GasQuant. J. Geophys. Res. Oceans Vol. 113 Issue C7 CiteID C07048 113, 7048. doi:10.1029/2007JC004704 Schneider von Deimling, J., Greinert, J., Chapman, N.R., Rabbel, W., Linke, P., 2010. Acoustic imaging of natural gas seepage in the North Sea: Sensing bubbles controlled by variable currents. Limnol. Oceanogr. Methods 8, 155. doi:10.4319/lom.2010.8.155

  2. Application of hydroacoustics to investigate the distribution, diel movement, and abundance of fish on Zhubi Reef, Nansha Islands, South China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Chen, Guobao; Chen, Zuozhi; Qiu, Yongsong; Xiong, Dan

    2016-09-01

    A combination of traditional fish sampling methods (hand-line and gill net) and modern hydroacoustic techniques were used to study fish community structure, distribution, and diel movements of fish on Zhubi Reef to enhance understanding of the ecosystem. We collected 126 individuals from 29 species, 20 genera, 17 families, three orders, and two classes using traditional gear. Perciforms were the dominant group in terms of species richness and biomass. The acoustic data indicated that very small (target strength [TS], dB) <-60 dB) and small (-60 dB≤TS<-45 dB) fish contributed the most to abundance and species richness on the coral reef, and that the proportion of medium-sized (-45 dB≤TS<-35 dB) and large-sized (-35 dB≤TS) fish increased gradually as depth increased. The single-target detection method revealed two distinct size classes during the day in the 12-16 and 16-20-m layers. One group consisted of very small-sized fish (TS<-60 dB) and the other consisted of medium and large-sized fish (TS>-55 dB). The number of single-target detections was significantly higher during the night than during the day ( P<0.05). The singletarget TS frequency distribution during the day was significantly different than during the night at depths of 4-8, 8-12, 12-16, and 16-20 m. Significant differences were observed among the 4-8, 8-12, 12-16, and 16-20-m-depth layers during day and night. Diel vertical movement was evidenced as fish began to spread and move upward just before sunset and began to assemble and descend shortly (15 min) after sunrise.

  3. Concept Modeling-based Drug Repositioning

    PubMed Central

    Patchala, Jagadeesh; Jegga, Anil G

    2015-01-01

    Our hypothesis is that drugs and diseases sharing similar biomedical and genomic concepts are likely to be related, and thus repositioning opportunities can be identified by ranking drugs based on the incidence of shared similar concepts with diseases and vice versa. To test this, we constructed a probabilistic topic model based on the Unified Medical Language System (UMLS) concepts that appear in the disease and drug related abstracts in MEDLINE. The resulting probabilistic topic associations were used to measure the similarity between disease and drugs. The success of the proposed model is evaluated using a set of repositioned drugs, and comparing a drug’s ranking based on its similarity to the original and new indication. We then applied the model to rare disorders and compared them to all approved drugs to facilitate “systematically serendipitous” discovery of relationships between rare diseases and existing drugs, some of which could be potential repositioning candidates. PMID:26306277

  4. Model Based Reconstruction of UT Array Data

    NASA Astrophysics Data System (ADS)

    Calmon, P.; Iakovleva, E.; Fidahoussen, A.; Ribay, G.; Chatillon, S.

    2008-02-01

    Beyond the detection of defects, their characterization (identification, positioning, sizing) is one goal of great importance often assigned to the analysis of NDT data. The first step of such analysis in the case of ultrasonic testing amounts to image in the part the detected echoes. This operation is in general achieved by considering time of flights and by applying simplified algorithms which are often valid only on canonical situations. In this communication we present an overview of different imaging techniques studied at CEA LIST and based on the exploitation of direct models which enable to address complex configurations and are available in the CIVA software plat-form. We discuss in particular ray-model based algorithms, algorithms derived from classical synthetic focusing and processing of the full inter-element matrix (MUSIC algorithm).

  5. Model-based reasoning in SSF ECLSS

    NASA Technical Reports Server (NTRS)

    Miller, J. K.; Williams, George P. W., Jr.

    1992-01-01

    The interacting processes and reconfigurable subsystems of the Space Station Freedom Environmental Control and Life Support System (ECLSS) present a tremendous technical challenge to Freedom's crew and ground support. ECLSS operation and problem analysis is time-consuming for crew members and difficult for current computerized control, monitoring, and diagnostic software. These challenges can be at least partially mitigated by the use of advanced techniques such as Model-Based Reasoning (MBR). This paper will provide an overview of MBR as it is being applied to Space Station Freedom ECLSS. It will report on work being done to produce intelligent systems to help design, control, monitor, and diagnose Freedom's ECLSS. Specifically, work on predictive monitoring, diagnosability, and diagnosis, with emphasis on the automated diagnosis of the regenerative water recovery and air revitalization processes will be discussed.

  6. Model-based vision for space applications

    NASA Technical Reports Server (NTRS)

    Chaconas, Karen; Nashman, Marilyn; Lumia, Ronald

    1992-01-01

    This paper describes a method for tracking moving image features by combining spatial and temporal edge information with model based feature information. The algorithm updates the two-dimensional position of object features by correlating predicted model features with current image data. The results of the correlation process are used to compute an updated model. The algorithm makes use of a high temporal sampling rate with respect to spatial changes of the image features and operates in a real-time multiprocessing environment. Preliminary results demonstrate successful tracking for image feature velocities between 1.1 and 4.5 pixels every image frame. This work has applications for docking, assembly, retrieval of floating objects and a host of other space-related tasks.

  7. Model-Based Vision Using Relational Summaries

    NASA Astrophysics Data System (ADS)

    Lu, Haiyuan; Shapiro, Linda G.

    1989-03-01

    A CAD-to-vision system is a computer system that inputs a CAD model of an object and outputs a vision model and matching procedure by which that object can be recognized and/or its position and orientation determined. CAD-model-based systems are extremely useful for industrial vision tasks where a number of different manufactured parts must be automatically manipulated and/or inspected. Another area where vision systems based on CAD models is becoming important is in the United States space program. Since the space station and space vehicles are recent or even current designs, we can expect to have CAD models of these objects to work with. Vision tasks in space such as docking and tracking of vehicles, guided assembly tasks, and inspection of the space station itself for cracks and other problems can rely on model-directed vision techniques.

  8. Model-based reconfiguration: Diagnosis and recovery

    NASA Technical Reports Server (NTRS)

    Crow, Judy; Rushby, John

    1994-01-01

    We extend Reiter's general theory of model-based diagnosis to a theory of fault detection, identification, and reconfiguration (FDIR). The generality of Reiter's theory readily supports an extension in which the problem of reconfiguration is viewed as a close analog of the problem of diagnosis. Using a reconfiguration predicate 'rcfg' analogous to the abnormality predicate 'ab,' we derive a strategy for reconfiguration by transforming the corresponding strategy for diagnosis. There are two obvious benefits of this approach: algorithms for diagnosis can be exploited as algorithms for reconfiguration and we have a theoretical framework for an integrated approach to FDIR. As a first step toward realizing these benefits we show that a class of diagnosis engines can be used for reconfiguration and we discuss algorithms for integrated FDIR. We argue that integrating recovery and diagnosis is an essential next step if this technology is to be useful for practical applications.

  9. Model-based ocean acoustic passive localization

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1994-01-24

    The detection, localization and classification of acoustic sources (targets) in a hostile ocean environment is a difficult problem -- especially in light of the improved design of modern submarines and the continual improvement in quieting technology. Further the advent of more and more diesel-powered vessels makes the detection problem even more formidable than ever before. It has recently been recognized that the incorporation of a mathematical model that accurately represents the phenomenology under investigation can vastly improve the performance of any processor, assuming, of course, that the model is accurate. Therefore, it is necessary to incorporate more knowledge about the ocean environment into detection and localization algorithms in order to enhance the overall signal-to-noise ratios and improve performance. An alternative methodology to matched-field/matched-mode processing is the so-called model-based processor which is based on a state-space representation of the normal-mode propagation model. If state-space solutions can be accomplished, then many of the current ocean acoustic processing problems can be analyzed and solved using this framework to analyze performance results based on firm statistical and system theoretic grounds. The model-based approach, is (simply) ``incorporating mathematical models of both physical phenomenology and the measurement processes including noise into the processor to extract the desired information.`` In this application, we seek techniques to incorporate the: (1) ocean acoustic propagation model; (2) sensor array measurement model; and (3) noise models (ambient, shipping, surface and measurement) into a processor to solve the associated localization/detection problems.

  10. Fast Algorithms for Model-Based Diagnosis

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Barrett, Anthony; Vatan, Farrokh; Mackey, Ryan

    2005-01-01

    Two improved new methods for automated diagnosis of complex engineering systems involve the use of novel algorithms that are more efficient than prior algorithms used for the same purpose. Both the recently developed algorithms and the prior algorithms in question are instances of model-based diagnosis, which is based on exploring the logical inconsistency between an observation and a description of a system to be diagnosed. As engineering systems grow more complex and increasingly autonomous in their functions, the need for automated diagnosis increases concomitantly. In model-based diagnosis, the function of each component and the interconnections among all the components of the system to be diagnosed (for example, see figure) are represented as a logical system, called the system description (SD). Hence, the expected behavior of the system is the set of logical consequences of the SD. Faulty components lead to inconsistency between the observed behaviors of the system and the SD. The task of finding the faulty components (diagnosis) reduces to finding the components, the abnormalities of which could explain all the inconsistencies. Of course, the meaningful solution should be a minimal set of faulty components (called a minimal diagnosis), because the trivial solution, in which all components are assumed to be faulty, always explains all inconsistencies. Although the prior algorithms in question implement powerful methods of diagnosis, they are not practical because they essentially require exhaustive searches among all possible combinations of faulty components and therefore entail the amounts of computation that grow exponentially with the number of components of the system.

  11. The A2A adenosine receptor rescues neuritogenesis impaired by p53 blockage via KIF2A, a kinesin family member.

    PubMed

    Sun, Chung-Nan; Chuang, Hsiu-Chun; Wang, Jiz-Yuh; Chen, Si-Ying; Cheng, Ya-Yun; Lee, Chien-Fei; Chern, Yijuang

    2010-07-01

    The A2A adenosine receptor (A2AR) is a G-protein-coupled receptor. We previously reported that the C terminus of the A2AR binds to translin-associated protein X (TRAX) and modulates nerve growth factor (NGF)-evoked neurite outgrowth in PC12 cells. Herein, we show that neuritogenesis of primary hippocampal neurons requires p53 because blockage of p53 suppressed neurite outgrowth. The impaired neuritogenesis caused by p53 blockage was rescued by activation of the A2AR (designated the A2A rescue effect) in a TRAX-dependent manner. Importantly, suppression of a TRAX-interacting protein (kinesin heavy chain member 2A, KIF2A) inhibited the A2A rescue effect, whereas overexpression of KIF2A caused a rescue effect. Expression of a KIF2A fragment (KIF2A514), which disturbed the interaction between KIF2A and TRAX, blocked the rescue effect. Transient colocalization of TRAX and KIF2A was detected in the nucleus of PC12 cells upon NGF treatment. These data suggest that functional interaction between KIF2A and TRAX is critical for the A2A rescue effect. Moreover, p53 blockage during NGF treatment prevented the redistribution of KIF2A from the nucleus to the cytoplasmic region. Expression of a nuclear-retained KIF2A variant (NLS-KIF2A) did not rescue the impaired neurite outgrowth as did the wild-type KIF2A. Therefore, redistribution of KIF2A to the cytoplasmic fraction is a prerequisite for neurite outgrowth. Collectively, we demonstrate that KIF2A functions downstream of p53 to mediate neuritogenesis of primary hippocampal neurons and PC12 cells. Stimulation of the A2AR rescued neuritogenesis impaired by p53 blockage via an interaction between TRAX and KIF2A. PMID:20506231

  12. Blockage of angiotensin II type I receptor decreases the synthesis of growth factors and induces apoptosis in C6 cultured cells and C6 rat glioma

    PubMed Central

    Arrieta, O; Guevara, P; Escobar, E; García-Navarrete, R; Pineda, B; Sotelo, J

    2005-01-01

    Angiotensin II (Ang II) is a main effector peptide in the renin–angiotensin system and participates in the regulation of vascular tone. It also has a role in the expression of growth factors that induce neovascularisation which is closely associated to the growth of malignant gliomas. We have shown that the selective blockage of the AT1 receptor of angiotensin inhibites tumour growth, cell proliferation and angiogenesis of C6 rat glioma. The aim of this study was to study the effects of the blockage of AT1 receptor on the synthesis of growth factors, and in the genesis of apoptosis in cultured C6 glioma cells and in rats with C6 glioma. Administration of losartan at doses of 40 or 80 mg kg−1 to rats with C6 glioma significantly decreased tumoral volume and production of platelet-derived growth factor, vascular endothelial growth factor and basic fibroblast growth factor. It also induced apoptosis in a dose-dependent manner. Administration of Ang II increased cell proliferation of cultured C6 cells which decreased by the administration of losartan. Our results suggest that the selective blockage of AT1 diminishes tumoral growth through inhibition of growth factors and promotion of apoptosis. PMID:15785746

  13. Blockage of Galectin-receptor Interactions by α-lactose Exacerbates Plasmodium berghei-induced Pulmonary Immunopathology

    PubMed Central

    Liu, Jinfeng; Huang, Shiguang; Su, Xin-zhuan; Song, Jianping; Lu, Fangli

    2016-01-01

    Malaria-associated acute lung injury (ALI) is a frequent complication of severe malaria that is often caused by “excessive” immune responses. To better understand the mechanism of ALI in malaria infection, here we investigated the roles of galectin (Gal)-1, 3, 8, 9 and the receptors of Gal-9 (Tim-3, CD44, CD137, and PDI) in malaria-induced ALI. We injected alpha (α)-lactose into mice-infected with Plasmodium berghei ANKA (PbANKA) to block galectins and found significantly elevated total proteins in bronchoalveolar lavage fluid, higher parasitemia and tissue parasite burden, and increased numbers of CD68+ alveolar macrophages as well as apoptotic cells in the lungs after blockage. Additionally, mRNA levels of Gal-9, Tim-3, CD44, CD137, and PDI were significantly increased in the lungs at day 5 after infection, and the levels of CD137, IFN-α, IFN-β, IFN-γ, IL-4, and IL-10 in the lungs were also increased after α-lactose treatment. Similarly, the levels of Gal-9, Tim-3, IFN-α, IFN-β, IFN-γ, and IL-10 were all significantly increased in murine peritoneal macrophages co-cultured with PbANKA-infected red blood cells in vitro; but only IFN-α and IFN-β were significantly increased after α-lactose treatment. Our data indicate that Gal-9 interaction with its multiple receptors play an important role in murine malaria-associated ALI. PMID:27554340

  14. Hypertonic conditions trigger transient plasmolysis, growth arrest and blockage of transporter endocytosis in Aspergillus nidulans and Saccharomyces cerevisiae.

    PubMed

    Bitsikas, Vassilis; Karachaliou, Mayia; Gournas, Christos; Diallinas, George

    2011-01-01

    By using Aspergillus nidulans strains expressing functional GFP-tagged transporters under hypertonic conditions, we noticed the rapid appearance of cortical, relatively static, fluorescent patches (0.5-2.3 μm). These patches do not correspond to transporter microdomains as they co-localize with other plasma membrane-associated molecules, such as the pleckstrin homology (PH) domain and the SsoA t-Snare, or the lipophilic markers FM4-64 and filipin. In addition, they do not show characteristics of lipid rafts, MCCs or other membrane microdomains. Deconvoluted microscopic images showed that fluorescent patches correspond to plasma membrane invaginations. Transporters remain fully active during this phenomenon of localized plasmolysis. Plasmolysis was however associated with reduced growth rate and a dramatic blockage in transporter and FM4-64 endocytosis. These phenomena are transient and rapidly reversible upon wash-out of hypertonic media. Based on the observation that block in endocytosis by hypertonic treatment altered dramatically the cellular localization of tropomyosin (GFP-TpmA), although it did not affect the cortical appearance of upstream (SlaB-GFP) or downstream (AbpA-mRFP) endocytic components, we conclude that hypertonicity modifies actin dynamics and thus acts indirectly on endocytosis. This was further supported by the effect of latrunculin B, an actin depolymerization agent, on endocytosis. We show that the phenomena observed in A. nidulans also occur in Saccharomyces cerevisiae, suggesting that they constitute basic homeostatic responses of ascomycetes to hypertonic shock. Finally, our work shows that hypertonic treatments can be used as physiological tools to study the endocytic down-regulation of transporters in A. nidulans, as non-conditional genetic blocks affecting endocytic internalization are lethal or severely debilitating. PMID:20919858

  15. Model-based phase-shifting interferometer

    NASA Astrophysics Data System (ADS)

    Liu, Dong; Zhang, Lei; Shi, Tu; Yang, Yongying; Chong, Shiyao; Miao, Liang; Huang, Wei; Shen, Yibing; Bai, Jian

    2015-10-01

    A model-based phase-shifting interferometer (MPI) is developed, in which a novel calculation technique is proposed instead of the traditional complicated system structure, to achieve versatile, high precision and quantitative surface tests. In the MPI, the partial null lens (PNL) is employed to implement the non-null test. With some alternative PNLs, similar as the transmission spheres in ZYGO interferometers, the MPI provides a flexible test for general spherical and aspherical surfaces. Based on modern computer modeling technique, a reverse iterative optimizing construction (ROR) method is employed for the retrace error correction of non-null test, as well as figure error reconstruction. A self-compiled ray-tracing program is set up for the accurate system modeling and reverse ray tracing. The surface figure error then can be easily extracted from the wavefront data in forms of Zernike polynomials by the ROR method. Experiments of the spherical and aspherical tests are presented to validate the flexibility and accuracy. The test results are compared with those of Zygo interferometer (null tests), which demonstrates the high accuracy of the MPI. With such accuracy and flexibility, the MPI would possess large potential in modern optical shop testing.

  16. [Fast spectral modeling based on Voigt peaks].

    PubMed

    Li, Jin-rong; Dai, Lian-kui

    2012-03-01

    Indirect hard modeling (IHM) is a recently introduced method for quantitative spectral analysis, which was applied to the analysis of nonlinear relation between mixture spectrum and component concentration. In addition, IHM is an effectual technology for the analysis of components of mixture with molecular interactions and strongly overlapping bands. Before the establishment of regression model, IHM needs to model the measured spectrum as a sum of Voigt peaks. The precision of the spectral model has immediate impact on the accuracy of the regression model. A spectrum often includes dozens or even hundreds of Voigt peaks, which mean that spectral modeling is a optimization problem with high dimensionality in fact. So, large operation overhead is needed and the solution would not be numerically unique due to the ill-condition of the optimization problem. An improved spectral modeling method is presented in the present paper, which reduces the dimensionality of optimization problem by determining the overlapped peaks in spectrum. Experimental results show that the spectral modeling based on the new method is more accurate and needs much shorter running time than conventional method. PMID:22582612

  17. Model-Based Method for Sensor Validation

    NASA Technical Reports Server (NTRS)

    Vatan, Farrokh

    2012-01-01

    Fault detection, diagnosis, and prognosis are essential tasks in the operation of autonomous spacecraft, instruments, and in situ platforms. One of NASA s key mission requirements is robust state estimation. Sensing, using a wide range of sensors and sensor fusion approaches, plays a central role in robust state estimation, and there is a need to diagnose sensor failure as well as component failure. Sensor validation can be considered to be part of the larger effort of improving reliability and safety. The standard methods for solving the sensor validation problem are based on probabilistic analysis of the system, from which the method based on Bayesian networks is most popular. Therefore, these methods can only predict the most probable faulty sensors, which are subject to the initial probabilities defined for the failures. The method developed in this work is based on a model-based approach and provides the faulty sensors (if any), which can be logically inferred from the model of the system and the sensor readings (observations). The method is also more suitable for the systems when it is hard, or even impossible, to find the probability functions of the system. The method starts by a new mathematical description of the problem and develops a very efficient and systematic algorithm for its solution. The method builds on the concepts of analytical redundant relations (ARRs).

  18. Model-based target and background characterization

    NASA Astrophysics Data System (ADS)

    Mueller, Markus; Krueger, Wolfgang; Heinze, Norbert

    2000-07-01

    Up to now most approaches of target and background characterization (and exploitation) concentrate solely on the information given by pixels. In many cases this is a complex and unprofitable task. During the development of automatic exploitation algorithms the main goal is the optimization of certain performance parameters. These parameters are measured during test runs while applying one algorithm with one parameter set to images that constitute of image domains with very different domain characteristics (targets and various types of background clutter). Model based geocoding and registration approaches provide means for utilizing the information stored in GIS (Geographical Information Systems). The geographical information stored in the various GIS layers can define ROE (Regions of Expectations) and may allow for dedicated algorithm parametrization and development. ROI (Region of Interest) detection algorithms (in most cases MMO (Man- Made Object) detection) use implicit target and/or background models. The detection algorithms of ROIs utilize gradient direction models that have to be matched with transformed image domain data. In most cases simple threshold calculations on the match results discriminate target object signatures from the background. The geocoding approaches extract line-like structures (street signatures) from the image domain and match the graph constellation against a vector model extracted from a GIS (Geographical Information System) data base. Apart from geo-coding the algorithms can be also used for image-to-image registration (multi sensor and data fusion) and may be used for creation and validation of geographical maps.

  19. Enhancing model based forecasting of geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Webb, Alla G.

    Modern society is increasingly dependent on the smooth operation of large scale technology supporting Earth based activities such as communication, electricity distribution, and navigation. This technology is potentially threatened by global geomagnetic storms, which are caused by the impact of plasma ejected from the Sun upon the protective magnetic field that surrounds the Earth. Forecasting the timing and magnitude of these geomagnetic storms is part of the emerging discipline of space weather. The most severe geomagnetic storms are caused by magnetic clouds, whose properties and characteristics are important variables in space weather forecasting systems. The methodology presented here is the development of a new statistical approach to characterize the physical properties (variables) of the magnetic clouds and to examine the extent to which theoretical models can be used in describing both of these physical properties, as well as their evolution in space and time. Since space weather forecasting is a complex system, a systems engineering approach is used to perform analysis, validation, and verification of the magnetic cloud models (subsystem of the forecasting system) using a model-based methodology. This research demonstrates that in order to validate magnetic cloud models, it is important to categorize the data by physical parameters such as velocity and distance travelled. This understanding will improve the modeling accuracy of magnetic clouds in space weather forecasting systems and hence increase forecasting accuracy of geomagnetic storms and their impact on earth systems.

  20. Model based systems engineering for astronomical projects

    NASA Astrophysics Data System (ADS)

    Karban, R.; Andolfato, L.; Bristow, P.; Chiozzi, G.; Esselborn, M.; Schilling, M.; Schmid, C.; Sommer, H.; Zamparelli, M.

    2014-08-01

    Model Based Systems Engineering (MBSE) is an emerging field of systems engineering for which the System Modeling Language (SysML) is a key enabler for descriptive, prescriptive and predictive models. This paper surveys some of the capabilities, expectations and peculiarities of tools-assisted MBSE experienced in real-life astronomical projects. The examples range in depth and scope across a wide spectrum of applications (for example documentation, requirements, analysis, trade studies) and purposes (addressing a particular development need, or accompanying a project throughout many - if not all - its lifecycle phases, fostering reuse and minimizing ambiguity). From the beginnings of the Active Phasing Experiment, through VLT instrumentation, VLTI infrastructure, Telescope Control System for the E-ELT, until Wavefront Control for the E-ELT, we show how stepwise refinements of tools, processes and methods have provided tangible benefits to customary system engineering activities like requirement flow-down, design trade studies, interfaces definition, and validation, by means of a variety of approaches (like Model Checking, Simulation, Model Transformation) and methodologies (like OOSEM, State Analysis)

  1. Urine Blockage in Newborns

    MedlinePlus

    ... in the mother’s womb, called prenatal development, the placenta—a temporary organ joining mother and baby—controls ... to 12 weeks after conception. However, the mother’s placenta continues to do most of the work until ...

  2. Blockage of upper airway

    MedlinePlus

    ... closed, including allergic reactions to a bee sting , peanuts, antibiotics (such as penicillin), and blood pressure medicines ( ... from breathing in smoke Foreign bodies, such as peanuts and other breathed-in foods, pieces of a ...

  3. Urine Blockage in Newborns

    MedlinePlus

    ... to Know About My Child's Urinary Tract Infection​ Contact Us Health Information Center Phone: 1-800-860- ... Health Information Center, Telephone: 1-800-860-8747 Contact the NIDDK Health Information Center Phone: 1-800- ...

  4. Blockage of upper airway

    MedlinePlus

    ... Airway obstruction - acute upper Images Throat anatomy Choking Respiratory system References Cukor J, Manno M. Pediatric respiratory emergencies: upper airway obstruction and infections. In: Marx ...

  5. Remote-sensing of Riverine Environments Utilized by Spawning Pallid Sturgeon Using a Suite of Hydroacoustic Tools and High-resolution DEMs

    NASA Astrophysics Data System (ADS)

    Elliott, C. M.; Jacobson, R. B.; DeLonay, A. J.; Braaten, P. J.

    2013-12-01

    The pallid sturgeon (Scaphirynchus albus) inhabits sandy-bedded rivers in the Mississippi River basin including the Missouri and Lower Yellowstone Rivers and has experienced decline generally associated with the fragmentation and alteration of these river systems. Knowledge gaps in the life history of the pallid sturgeon include lack of an understanding of conditions needed for successful reproduction and recruitment. We employed hydroacoustic tools to investigate habitats utilized by spawning pallid sturgeon in the Missouri River in Missouri, Kansas, Iowa, and Nebraska, and the Yellowstone River in Montana and North Dakota USA from 2008-2013. Reproductive pallid sturgeon were tracked to suspected spawning locations by field crews using either acoustic or radio telemetry, a custom mobile mapping application, and differential global positioning systems (DGPS). Female pallid sturgeon were recaptured soon after spawning events to validate that eggs had been released. Habitats were mapped at presumed spawning and embryo incubation sites using a multibeam echosounder system (MBES), sidescan sonar, acoustic Doppler current profiler, an acoustic camera and either a real-time kinematic global positioning system (RTK GPS) or DGPS. High-resolution DEM's and velocimetric maps were gridded from at a variety of scales from 0.10 to 5 meters for characterization and visualization at spawning and presumed embryo incubation sites. Pallid sturgeon spawning sites on the Missouri River are deep (6-8 meters) and have high current velocities (>1.5 meters per second). These sites are also characterized by high turbidity and high rates of bedload sediment transport in the form of migrating sand dunes. Spawning on the channelized Lower Missouri River occurs on or adjacent to coarse angular bank revetment or bedrock. Collecting biophysical information in these environmental conditions is challenging, and there is a need to characterize the substrate and substrate condition at a scale

  6. Numerical Modelling of circulation and internal tides on the Crozet plateau in support of the IMS/CTBTO hydroacoustic installation HA04

    NASA Astrophysics Data System (ADS)

    Lyard, Florent Henri; Zampolli, Mario; Marsaleix, Patrick

    2014-05-01

    Hydrophone stations of the Comprehensive Nuclear-Test-Ban Organisation (CTBTO) International Monitoring System (IMS), with the exception of one in Australia, comprise two triplets of submerged moored hydrophones, one North and one South of the island from which the respective system is deployed. Triplet distances vary approximately between 50 - 100 km kilometres from the island, with each triplet connected to the receiving shore equipment by fibre-optic submarine data cables. Once deployed, the systems relay underwater acoustic waveforms in the band 1 - 100 Hz in real time to Vienna via a shore based satellite link. The design life of hydroacoustic stations is at least 20 years, without need for any maintenance of the underwater system. The re-establishment of hydrophone monitoring station HA04 at Crozet (French Southern and Antarctic Territories) in the South-Western Indian Ocean is currently being investigated. The highly dynamic ocean environment at Crozet is governed by strong winds and generally high sea states at the surface, local circulation emanating from the sub-Antarctic front (SAF) and the Agulhas return current (ARC), moderate surface tides and strong internal tides. Deploying the submarine cables and triplets in such an environment requires careful evaluation of all risks and in particular the minimization of the exposure of the deployed system to excessively strong currents. This issue has been addressed by two studies which are briefly introduced here. In the first study, a linear spectral model was used to study and characterize the barotropic tide-driven currents on the Crozet plateau in three spatial dimensions. The M2 semi-diurnal component was shown to dominate in the area, driving sizeable internal tides. The estimate was quantitatively and spatially refined in the second study, in which a time stepping model was used taking into account the local ocean climatology and stratification, as well as the interplay between the seasonally varying

  7. Model Based Autonomy for Robust Mars Operations

    NASA Technical Reports Server (NTRS)

    Kurien, James A.; Nayak, P. Pandurang; Williams, Brian C.; Lau, Sonie (Technical Monitor)

    1998-01-01

    Space missions have historically relied upon a large ground staff, numbering in the hundreds for complex missions, to maintain routine operations. When an anomaly occurs, this small army of engineers attempts to identify and work around the problem. A piloted Mars mission, with its multiyear duration, cost pressures, half-hour communication delays and two-week blackouts cannot be closely controlled by a battalion of engineers on Earth. Flight crew involvement in routine system operations must also be minimized to maximize science return. It also may be unrealistic to require the crew have the expertise in each mission subsystem needed to diagnose a system failure and effect a timely repair, as engineers did for Apollo 13. Enter model-based autonomy, which allows complex systems to autonomously maintain operation despite failures or anomalous conditions, contributing to safe, robust, and minimally supervised operation of spacecraft, life support, In Situ Resource Utilization (ISRU) and power systems. Autonomous reasoning is central to the approach. A reasoning algorithm uses a logical or mathematical model of a system to infer how to operate the system, diagnose failures and generate appropriate behavior to repair or reconfigure the system in response. The 'plug and play' nature of the models enables low cost development of autonomy for multiple platforms. Declarative, reusable models capture relevant aspects of the behavior of simple devices (e.g. valves or thrusters). Reasoning algorithms combine device models to create a model of the system-wide interactions and behavior of a complex, unique artifact such as a spacecraft. Rather than requiring engineers to all possible interactions and failures at design time or perform analysis during the mission, the reasoning engine generates the appropriate response to the current situation, taking into account its system-wide knowledge, the current state, and even sensor failures or unexpected behavior.

  8. Effects of physical blockage of axial phloem transport on growth of Norway spruce (Picea abies) saplings under drought

    NASA Astrophysics Data System (ADS)

    Oberhuber, Walter; Gruber, Andreas; Winkler, Andrea; Lethaus, Gina; Wieser, Gerhard

    2016-04-01

    Early culmination of maximum radial growth in late spring was found in several coniferous species in a dry inner Alpine environment (Oberhuber et al. 2014). We hypothesized that early decrease in radial stem growth is an adaptation to cope with drought stress, which might require an early switch of carbon allocation to belowground organs. To test this hypothesis we manipulated tree carbon status by physical blockage of phloem transport and soil water availability of Norway spruce saplings (tree height c. 1.5 m) in a common garden experiment to investigate influence of carbon availability and drought on above- and belowground growth. Girdling occurred at different phenological stages during the growing season, i.e., before growth onset, and during earlywood and latewood formation. Non-structural carbohydrates (NSC, soluble sugars and starch) were determined before and after the growing season to evaluate change in tree carbon status. Tree ring analysis revealed that compared to non-girdled controls earlywood width above girdling strikingly increased by c. 170 and 440 %, while latewood width decreased by c. 85 and 55 % in watered and drought stressed trees, respectively. Below girdling no xylem formation was detected. Unexpectedly, preliminary analyses of carbon status revealed striking reduction (c. -80 %) of NSC above and below girdling. Most likely due to reductions in xylem hydraulic conductance, girdling before growth onset reduced leader shoot growth compared to non-girdled controls by c. 45 %, irrespective of water availability. Root dry mass of girdled trees was significantly reduced compared to non-girdled controls (c. 30 % in drought stressed and 45 % in watered trees; p < 0.001). Results suggest that in Norway spruce saplings (1) carbon availability affects radial stem growth, (2) higher basipetal carbon transport occurs under drought supporting our hypothesis of early switch of carbon allocation to belowground when drought stress prevails and (3) minor

  9. Development of hydroacoustical techniques for the monitoring and classification of benthic habitats in Puck Bay: Modeling of acoustic waves scattering by seagrass

    NASA Astrophysics Data System (ADS)

    Raczkowska, A.; Gorska, N.

    2012-12-01

    Puck Bay is an area of high species biodiversity belonging to the Coastal Landscape Park of Baltic Sea Protected Areas (BSPA) and is also included in the list of the World Wide Fund for Nature (WWF) and covered by the protection program "Natura 2000". The underwater meadows of the Puck Bay are important for Europe's natural habitats due to their role in enhancing the productivity of marine ecosystems and providing shelter and optimal feeding conditions for many marine organisms. One of the dominant species comprising the underwater meadows of the Southern Baltic Sea is the seagrass Zostera marina. The spatial extent of underwater seagrass meadows is altered by pollution and eutrophication; therefore, to properly manage the area one must monitor its ecological state. Remote acoustic methods are useful tools for the monitoring of benthic habitats in many marine areas because they are non-invasive and allow researchers to obtain data from a large area in a short period of time. Currently there is a need to apply these methods in the Baltic Sea. Here we present an analysis of the mechanism of scattering of acoustic waves on seagrass in the Southern Baltic Sea based on the numerical modeling of acoustic wave scattering by the biological tissues of plants. The study was conducted by adapting a model developed on the basis of DWBA (Distorted Wave Born Approximation) developed by Stanton and Chu (2005) for fluid-like objects, including the characteristics of the Southern Baltic seagrass. Input data for the model, including the morphometry of seagrass leaves, their angle of inclination and the density plant cover, was obtained through the analysis of biological materials collected in the Puck Bay in the framework of a research project financed by the Polish Government (Development of hydroacoustic methods for studies of underwater meadows of Puck Bay, 6P04E 051 20). On the basis of the developed model, we have analyzed the dependence of the target strength of a single

  10. Models-Based Practice: Great White Hope or White Elephant?

    ERIC Educational Resources Information Center

    Casey, Ashley

    2014-01-01

    Background: Many critical curriculum theorists in physical education have advocated a model- or models-based approach to teaching in the subject. This paper explores the literature base around models-based practice (MBP) and asks if this multi-models approach to curriculum planning has the potential to be the great white hope of pedagogical change…

  11. Model-Based Software Testing for Object-Oriented Software

    ERIC Educational Resources Information Center

    Biju, Soly Mathew

    2008-01-01

    Model-based testing is one of the best solutions for testing object-oriented software. It has a better test coverage than other testing styles. Model-based testing takes into consideration behavioural aspects of a class, which are usually unchecked in other testing methods. An increase in the complexity of software has forced the software industry…

  12. Learning of Chemical Equilibrium through Modelling-Based Teaching

    ERIC Educational Resources Information Center

    Maia, Poliana Flavia; Justi, Rosaria

    2009-01-01

    This paper presents and discusses students' learning process of chemical equilibrium from a modelling-based approach developed from the use of the "Model of Modelling" diagram. The investigation was conducted in a regular classroom (students 14-15 years old) and aimed at discussing how modelling-based teaching can contribute to students learning…

  13. Argumentation in Science Education: A Model-Based Framework

    ERIC Educational Resources Information Center

    Bottcher, Florian; Meisert, Anke

    2011-01-01

    The goal of this article is threefold: First, the theoretical background for a model-based framework of argumentation to describe and evaluate argumentative processes in science education is presented. Based on the general model-based perspective in cognitive science and the philosophy of science, it is proposed to understand arguments as reasons…

  14. Nasal NK/T cell lymphoma presents with long-term nasal blockage and fever: a rare case report and literature review

    PubMed Central

    Zou, Hai; Pan, Ke-Hua; Wu, Liang; Pan, Hong-Ying; Ding, Ya-Hui; Zheng, Ming-Hua

    2016-01-01

    NK/T cell lymphoma (NKTCL) is a common disease which is a threat to human health. Nasal NKTCL is a rare but serious type of systemic lymphoma because of its high mortality rate and serious complications. In this case report, we describe a male who presented with nasal blockage in the right side, a fever of one month duration and a soy-like, painless and gradually increasing mass in the right submandibular region due to nasal NKTCL. The patient had no significant medical history and the initial clinical symptoms were nasal blockage. Contrast computed tomography showed that the nasopharyngeal mucosa was thickened and that the celiac and retroperitoneal lymphaden was intumescent. Finally a biopsy, guided by nasal endoscopy and examined using flow cytometry confirmed a diagnosis of NKTCL. Nasal NKTCL is rare and has no unique characteristics at first presentation, such as epidemiology and obvious clinical manifestation. As no effective therapy is currently available for this disease, early diagnosis and therapy of nasal NKTCL remains challenging. PMID:26885897

  15. Use of molecular beacons to probe for messenger RNA release from ribosomes during 5'-translational blockage by consecutive low-usage codons in Escherichia coli

    NASA Astrophysics Data System (ADS)

    Gao, Wenwu; Tyagi, Sanjay; Kramer, Fred R.; Goldman, Emanuel

    2000-03-01

    In `5'-translational blockage,' significantly reduced yields of proteins are synthesized in Escherichia coli when consecutive low-usage codons are inserted near translation starts of messages (with reduced or no effect when these same codons are inserted downstream). We tested the hypothesis that ribosomes encountering these low-usage codons prematurely release the mRNA. RNA from polysome gradients was fractionated into pools of polysomes, monosomes and ribosomes-free. New hybridization probes, called `molecular beacons,' and standard slot-blots, were used to detect test messages containing either consecutive low-usage AGG (arginine) or synonymous high-usage CGU insertions near the 5' end. The results show an approximately twofold increase in the ratio of free to bound mRNA when the low-usage codons were present compared to high-usage codons. In contrast, there was no difference in the ratio of free to bound mRNA when consecutive low-usage CUA or high-usage CUG (leucine) codons were inserted, or when the arginine codons were inserted near the 3' end. These data indicate that at least some mRNA is released from ribosomes during 5'-translational blockage by arginine but not leucine codons, and they support proposals that premature termination of translation can occur in some conditions in vivo in the absence of a stop codon.

  16. Iliofemoral-popliteal deep vein thrombosis at 35(th) week of pregnancy: treated with cesarean section and vena cava blockage plus thrombectomy.

    PubMed

    Mehmet Burgazlı, K; Altay, Metin M; Akdere, Hakan; Bilgin, Mehmet; Kavukcu, Ethem; Kill, Horst; Päfgen, Werner; Kubilay Ertan, A

    2012-01-01

    Pregnancy, due to its adaptive physiological changes, is a risk factor for deep vein thrombosis. Incidence of thromboembolic complications during pregnancy ranges from 0.76 to 1.72 per 1000 births. We present in this case report a pregnant woman with iliofemoral-popliteal deep vein thrombosis diagnosed at the 35(th) week of her pregnancy, who was treated with vena cava blockage and thrombectomy followed by cesarean section. Unfortunately, a rethrombosis developed in the patient after three days. We determined that the a-v fistula was blocked and not working. We found additionally that the deep vein thrombosis was closing the iliac vein completely on the left side and the blockage descending down through the inferior vena cava inlet with MRI. The patient underwent insertion of a retrievable vena cava filter, two stent implantation to the venous narrowings and surgical iliofemoral venous thrombectomy with concomitant re-creation of a temporary femoral arterio-venous fistula. Anticoagulation therapy with enoxaparine was started after the operation. The patient was discharged with warfarin under control of the INR value, and also with additional compression therapy (compression stockings) from the clinic. Without jeopardizing the mother and the baby, planning a combined surgical procedure, with a multidisciplinary approach is the best way to eliminate the risks of serious complications such as pulmonary embolism and mortality. PMID:24592024

  17. Selective β2-AR Blockage Suppresses Colorectal Cancer Growth Through Regulation of EGFR-Akt/ERK1/2 Signaling, G1-Phase Arrest, and Apoptosis.

    PubMed

    Chin, Chih-Chien; Li, Jhy-Ming; Lee, Kam-Fai; Huang, Yun-Ching; Wang, Kuan-Chieh; Lai, Hsiao-Ching; Cheng, Chih-Chung; Kuo, Yi-Hung; Shi, Chung-Sheng

    2016-02-01

    The stress-upregulated catecholamines-activated β1- and β2-adrenergic receptors (β1/2-ARs) have been shown to accelerate the progression of cancers such as colorectal cancer (CRC). We investigated the underlying mechanism of the inhibition of β1/2-ARs signaling for the treatment of CRC and elucidated the significance of β2-AR expression in CRC in vitro and in clinical samples. The impacts of β1/2-AR antagonists in CRC in vitro and CRC-xenograft in vivo were examined. We found that repression of β2-AR but not β1-AR signaling selectively suppressed cell viability, induced G1-phase cell cycle arrest, caused both intrinsic and extrinsic pathways-mediated apoptosis of specific CRC cells and inhibited CRC-xenograft growth in vivo. Moreover, the expression of β2-AR was not consistent with the progression of CRC in vitro or in clinical samples. Our data evidence that the expression profiles, signaling, and blockage of β2-AR have a unique pattern in CRC comparing to other cancers. β2-AR antagonism selectively suppresses the growth of CRC accompanying active β2-AR signaling, which potentially carries wild-type KRAS, in vitro and in vivo via the inhibition of β2-AR transactivated EFGR-Akt/ERK1/2 signaling pathway. Thus, β2-AR blockage might be a potential therapeutic strategy for combating the progressions of β2-AR-dependent CRC. PMID:26189563

  18. Model-Based Reasoning in Humans Becomes Automatic with Training

    PubMed Central

    Lübbert, Annika; Guitart-Masip, Marc; Dolan, Raymond J.

    2015-01-01

    Model-based and model-free reinforcement learning (RL) have been suggested as algorithmic realizations of goal-directed and habitual action strategies. Model-based RL is more flexible than model-free but requires sophisticated calculations using a learnt model of the world. This has led model-based RL to be identified with slow, deliberative processing, and model-free RL with fast, automatic processing. In support of this distinction, it has recently been shown that model-based reasoning is impaired by placing subjects under cognitive load—a hallmark of non-automaticity. Here, using the same task, we show that cognitive load does not impair model-based reasoning if subjects receive prior training on the task. This finding is replicated across two studies and a variety of analysis methods. Thus, task familiarity permits use of model-based reasoning in parallel with other cognitive demands. The ability to deploy model-based reasoning in an automatic, parallelizable fashion has widespread theoretical implications, particularly for the learning and execution of complex behaviors. It also suggests a range of important failure modes in psychiatric disorders. PMID:26379239

  19. Distributed real-time model-based diagnosis

    NASA Technical Reports Server (NTRS)

    Barrett, A. C.; Chung, S. H.

    2003-01-01

    This paper presents an approach to onboard anomaly diagnosis that combines the simplicity and real-time guarantee of a rule-based diagnosis system with the specification ease and coverage guarantees of a model-based diagnosis system.

  20. Qualitative model-based diagnosis using possibility theory

    NASA Technical Reports Server (NTRS)

    Joslyn, Cliff

    1994-01-01

    The potential for the use of possibility in the qualitative model-based diagnosis of spacecraft systems is described. The first sections of the paper briefly introduce the Model-Based Diagnostic (MBD) approach to spacecraft fault diagnosis; Qualitative Modeling (QM) methodologies; and the concepts of possibilistic modeling in the context of Generalized Information Theory (GIT). Then the necessary conditions for the applicability of possibilistic methods to qualitative MBD, and a number of potential directions for such an application, are described.

  1. Reduced model-based decision-making in schizophrenia.

    PubMed

    Culbreth, Adam J; Westbrook, Andrew; Daw, Nathaniel D; Botvinick, Matthew; Barch, Deanna M

    2016-08-01

    Individuals with schizophrenia have a diminished ability to use reward history to adaptively guide behavior. However, tasks traditionally used to assess such deficits often rely on multiple cognitive and neural processes, leaving etiology unresolved. In the current study, we adopted recent computational formalisms of reinforcement learning to distinguish between model-based and model-free decision-making in hopes of specifying mechanisms associated with reinforcement-learning dysfunction in schizophrenia. Under this framework, decision-making is model-free to the extent that it relies solely on prior reward history, and model-based if it relies on prospective information such as motivational state, future consequences, and the likelihood of obtaining various outcomes. Model-based and model-free decision-making was assessed in 33 schizophrenia patients and 30 controls using a 2-stage 2-alternative forced choice task previously demonstrated to discern individual differences in reliance on the 2 forms of reinforcement-learning. We show that, compared with controls, schizophrenia patients demonstrate decreased reliance on model-based decision-making. Further, parameter estimates of model-based behavior correlate positively with IQ and working memory measures, suggesting that model-based deficits seen in schizophrenia may be partially explained by higher-order cognitive deficits. These findings demonstrate specific reinforcement-learning and decision-making deficits and thereby provide valuable insights for understanding disordered behavior in schizophrenia. (PsycINFO Database Record PMID:27175984

  2. PNA binding to the non-template DNA strand interferes with transcription, suggesting a blockage mechanism mediated by R-loop formation.

    PubMed

    Belotserkovskii, Boris P; Hanawalt, Philip C

    2015-11-01

    Peptide Nucleic Acids (PNAs) are artificial DNA mimics with superior nucleic acid binding capabilities. T7 RNA polymerase (T7 RNAP) transcription upon encountering PNA bound to the non-template DNA strand was studied in vitro. A characteristic pattern of blockage signals was observed, extending downstream from the PNA binding site, similar to that produced by G-rich homopurine-homopyrimidine (hPu-hPy) sequences and likely caused by R-loop formation. Since blocked transcription complexes in association with stable R-loops may interfere with replication and in some cases trigger apoptosis, targeted R-loop formation might be employed to inactivate selected cells, such as those in tumors, based upon their unique complement of expressed genes. PMID:25175074

  3. Modeling and analysis framework for core damage propagation during flow-blockage-initiated accidents in the Advanced Neutron Source reactor at Oak Ridge National Laboratory

    SciTech Connect

    Kim, S.H.; Taleyarkhan, R.P.; Navarro-Valenti, S.; Georgevich, V.

    1995-12-31

    This paper describes modeling and analysis to evaluate the extent of core damage during flow blockage events in the Advanced Neutron Source (ANS) reactor planned to be built at ORNL. Damage propagation is postulated to occur from thermal conduction between dmaged and undamaged plates due to direct thermal contact. Such direct thermal contact may occur beause of fuel plate swelling during fission product vapor release or plate buckling. Complex phenomena of damage propagation were modeled using a one-dimensional heat transfer model. A parametric study was done for several uncertain variables. The study included investigating effects of plate contact area, convective heat transfer coefficient, thermal conductivity on fuel swelling, and initial temperature of the plate being contacted by the damaged plate. Also, the side support plates were modeled to account for their effects of damage propagation. Results provide useful insights into how variouss uncertain parameters affect damage propagation.

  4. R and D program for French sodium fast reactor: On the description and detection of sodium boiling phenomena during sub-assembly blockages

    SciTech Connect

    Vanderhaegen, M.; Paumel, K.; Seiler, J. M.; Tourin, A.; Jeannot, J. P.; Rodriguez, G.

    2011-07-01

    In support of the French ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) reactor program, which aims to demonstrate the industrial applicability of sodium fast reactors with an increased level of safety demonstration and availability compared to the past French sodium fast reactors, emphasis is placed on reactor instrumentation. It is in this framework that CEA studies continuous core monitoring to detect as early as possible the onset of sodium boiling. Such a detection system is of particular interest due to the rapid progress and the consequences of a Total Instantaneous Blockage (TIB) at a subassembly inlet, where sodium boiling intervenes in an early phase. In this paper, the authors describe all the particularities which intervene during the different boiling stages and explore possibilities for their detection. (authors)

  5. The Ridged Cross-Junction Multiple-Way Power Divider for Small Blockage and Symmetrical Slot Arrangement in the Center Feed Single-Layer Slotted Waveguide Array

    NASA Astrophysics Data System (ADS)

    Tsunemitsu, Yasuhiro; Yoshida, Goro; Goto, Naohisa; Hirokawa, Jiro; Ando, Makoto

    The center-feed in a single-layer slotted waveguide array [1]-[3] is one of the key components in polarization division duplex (PDD) wireless systems. Two center-feed arrays with orthogonal polarization and boresight beams are orthogonally arranged side-by-side for transmission and reception, simultaneously. Each antenna has extremely high XPD (almost 50dB in measurement) and a very high isolation (over 80dB in measurement) between two arrays is observed provided the symmetry of slot arrangement is preserved [4]. Unfortunately, the area blocked by the center feed causes high sidelobe levels. This paper proposes the ridged cross-junction multiple-way power divider for realizing blockage reduction and symmetrical slot arrangement at the same time.

  6. Bacterial protein AvrA stabilizes intestinal epithelial tight junctions via blockage of the C-Jun N-terminal kinase pathway.

    PubMed

    Zhang, Yongguo; Wu, Shaoping; Ma, Jun; Xia, Yinglin; Ai, Xun; Sun, Jun

    2015-01-01

    The Salmonella type III secretory system secretes virulence proteins, called effectors. Effectors are responsible for the alteration of tight junctions (TJ) and epithelial functions in intestinal infection and inflammation. In a previous study, we have demonstrated that a bacterial effector AvrA plays a role in stabilizing TJs and balancing the opposing action of other bacterial effectors. However, the molecular mechanisms by which AvrA-modulates TJ protein expression remain unknown. AvrA possesses acetyltransferase activity toward specific mitogen-activated protein kinase kinases (MAPKKs) and potently inhibits the c-Jun N-terminal kinase (JNK) pathway in inflammation. Inhibition of the JNK pathway is known to inhibit the TJ protein disassemble. Therefore, we hypothesize that AvrA stabilizes intestinal epithelial TJs via c-Jun and JNK pathway blockage. Using both in vitro and in vivo models, we showed that AvrA targets the c-Jun and JNK pathway that in turn stabilizes TJ protein ZO-1. Inhibition of JNK abolished the effect of AvrA on ZO-1. We further determined that AvrA suppressed the transcription factor activator protein-1, which was regulated by activated JNK. Moreover, we identified the functional domain of AvrA that directly regulated TJs using a series of AvrA mutants. The role of AvrA represents a highly refined bacterial strategy that helps the bacteria survive in the host and dampens the inflammatory response of the host. Our findings have uncovered a novel role of the bacterial protein AvrA in suppressing the inflammatory response of the host through JNK-regulated blockage of epithelial cell barrier function. PMID:25838979

  7. Acyl-coenzyme A:cholesterol acyltransferase 1 blockage enhances autophagy in the neurons of triple transgenic Alzheimer's disease mouse and reduces human P301L-tau content at the presymptomatic stage.

    PubMed

    Shibuya, Yohei; Niu, Zhaoyang; Bryleva, Elena Y; Harris, Brent T; Murphy, Stephanie R; Kheirollah, Alireza; Bowen, Zachary D; Chang, Catherine C Y; Chang, Ta-Yuan

    2015-07-01

    Patients with Alzheimer's disease (AD) display amyloidopathy and tauopathy. In mouse models of AD, pharmacological inhibition using small molecule enzyme inhibitors or genetic inactivation of acyl-coenzyme A (Acyl-CoA):cholesterol acyltransferase 1 (ACAT1) diminished amyloidopathy and restored cognitive deficits. In microglia, ACAT1 blockage increases autophagosome formation and stimulates amyloid β peptide1-42 degradation. Here, we hypothesize that in neurons ACAT1 blockage augments autophagy and increases autophagy-mediated degradation of P301L-tau protein. We tested this possibility in murine neuroblastoma cells ectopically expressing human tau and in primary neurons isolated from triple transgenic AD mice that express mutant forms of amyloid precursor protein, presenilin-1, and human tau. The results show that ACAT1 blockage increases autophagosome formation and decreases P301L-tau protein content without affecting endogenous mouse tau protein content. In vivo, lacking Acat1 decreases P301L-tau protein content in the brains of young triple transgenic AD mice but not in those of old mice, where extensive hyperphosphorylations and aggregation of P301L-tau take place. These results suggest that, in addition to ameliorating amyloidopathy in both young and old AD mice, ACAT1 blockage may benefit AD by reducing tauopathy at early stage. PMID:25930235

  8. Passive localization in ocean acoustics: A model-based approach

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1995-09-01

    A model-based approach is developed to solve the passive localization problem in ocean acoustics using the state-space formulation for the first time. It is shown that the inherent structure of the resulting processor consists of a parameter estimator coupled to a nonlinear optimization scheme. The parameter estimator is designed using the model-based approach in which an ocean acoustic propagation model is used in developing the model-based processor required for localization. Recall that model-based signal processing is a well-defined methodology enabling the inclusion of environmental (propagation) models, measurement (sensor arrays) models, and noise (shipping, measurement) models into a sophisticated processing algorithm. Here the parameter estimator is designed, or more appropriately the model-based identifier (MBID) for a propagation model developed from a shallow water ocean experiment. After simulation, it is then applied to a set of experimental data demonstrating the applicability of this approach. {copyright} {ital 1995} {ital Acoustical} {ital Society} {ital of} {ital America}.

  9. High-Order Hybridized Discontinuous Galerkin (HDG) Method for Wave Propagation Simulation in Complex Geophysical Media - Elastic, Acoustic and Hydro-Acoustic - an Unifying Framework to Couple Continuous Spectral Element and Discontinuous Galerkin Methods.

    NASA Astrophysics Data System (ADS)

    Sébastien, T.; Vilotte, J. P.; Guillot, L.; Mariotti, C.

    2014-12-01

    Today seismological observation systems combine broadband seismic receivers, hydrophones and micro-barometers antenna that provide complementary observations of source-radiated waves in heterogeneous and complex geophysical media. Exploiting these observations requires accurate and multi-physics - elastic, hydro-acoustic, infrasonic - wave simulation methods. A popular approach is the Spectral Element Method (SEM) (Chaljub et al, 2006) which is high-order accurate (low dispersion error), very flexible to parallelization and computationally attractive due to efficient sum factorization technique and diagonal mass matrix. However SEMs suffer from lack of flexibility in handling complex geometry and multi-physics wave propagation. High-order Discontinuous Galerkin Methods (DGMs), i.e. Dumbser et al (2006), Etienne et al. (2010), Wilcox et al (2010), are recent alternatives that can handle complex geometry, space-and-time adaptativity, and allow efficient multi-physics wave coupling at interfaces. However, DGMs are more memory demanding and less computationally attractive than SEMs, especially when explicit time stepping is used. We propose a new class of higher-order Hybridized Discontinuous Galerkin Spectral Elements (HDGSEM) methods for spatial discretization of wave equations, following the unifying framework for hybridization of Cockburn et al (2009) and Nguyen et al (2011), which allows for a single implementation of conforming and non-conforming SEMs. When used with energy conserving explicit time integration schemes, HDGSEM is flexible to handle complex geometry, computationally attractive and has significantly less degrees of freedom than classical DGMs, i.e., the only coupled unknowns are the single-valued numerical traces of the velocity field on the element's faces. The formulation can be extended to model fractional energy loss at interfaces between elastic, acoustic and hydro-acoustic media. Accuracy and performance of the HDGSEM are illustrated and

  10. Model-based ocean acoustic passive localization. Revision 1

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1994-06-01

    A model-based approach is developed (theoretically) to solve the passive localization problem. Here the authors investigate the design of a model-based identifier for a shallow water ocean acoustic problem characterized by a normal-mode model. In this problem they show how the processor can be structured to estimate the vertical wave numbers directly from measured pressure-field and sound speed measurements thereby eliminating the need for synthetic aperture processing or even a propagation model solution. Finally, they investigate various special cases of the source localization problem, designing a model-based localizer for each and evaluating the underlying structure with the expectation of gaining more and more insight into the general problem.

  11. Model Based Mission Assurance: Emerging Opportunities for Robotic Systems

    NASA Technical Reports Server (NTRS)

    Evans, John W.; DiVenti, Tony

    2016-01-01

    The emergence of Model Based Systems Engineering (MBSE) in a Model Based Engineering framework has created new opportunities to improve effectiveness and efficiencies across the assurance functions. The MBSE environment supports not only system architecture development, but provides for support of Systems Safety, Reliability and Risk Analysis concurrently in the same framework. Linking to detailed design will further improve assurance capabilities to support failures avoidance and mitigation in flight systems. This also is leading new assurance functions including model assurance and management of uncertainty in the modeling environment. Further, the assurance cases, a structured hierarchal argument or model, are emerging as a basis for supporting a comprehensive viewpoint in which to support Model Based Mission Assurance (MBMA).

  12. When Does Model-Based Control Pay Off?

    PubMed

    Kool, Wouter; Cushman, Fiery A; Gershman, Samuel J

    2016-08-01

    Many accounts of decision making and reinforcement learning posit the existence of two distinct systems that control choice: a fast, automatic system and a slow, deliberative system. Recent research formalizes this distinction by mapping these systems to "model-free" and "model-based" strategies in reinforcement learning. Model-free strategies are computationally cheap, but sometimes inaccurate, because action values can be accessed by inspecting a look-up table constructed through trial-and-error. In contrast, model-based strategies compute action values through planning in a causal model of the environment, which is more accurate but also more cognitively demanding. It is assumed that this trade-off between accuracy and computational demand plays an important role in the arbitration between the two strategies, but we show that the hallmark task for dissociating model-free and model-based strategies, as well as several related variants, do not embody such a trade-off. We describe five factors that reduce the effectiveness of the model-based strategy on these tasks by reducing its accuracy in estimating reward outcomes and decreasing the importance of its choices. Based on these observations, we describe a version of the task that formally and empirically obtains an accuracy-demand trade-off between model-free and model-based strategies. Moreover, we show that human participants spontaneously increase their reliance on model-based control on this task, compared to the original paradigm. Our novel task and our computational analyses may prove important in subsequent empirical investigations of how humans balance accuracy and demand. PMID:27564094

  13. Model Based Analysis and Test Generation for Flight Software

    NASA Technical Reports Server (NTRS)

    Pasareanu, Corina S.; Schumann, Johann M.; Mehlitz, Peter C.; Lowry, Mike R.; Karsai, Gabor; Nine, Harmon; Neema, Sandeep

    2009-01-01

    We describe a framework for model-based analysis and test case generation in the context of a heterogeneous model-based development paradigm that uses and combines Math- Works and UML 2.0 models and the associated code generation tools. This paradigm poses novel challenges to analysis and test case generation that, to the best of our knowledge, have not been addressed before. The framework is based on a common intermediate representation for different modeling formalisms and leverages and extends model checking and symbolic execution tools for model analysis and test case generation, respectively. We discuss the application of our framework to software models for a NASA flight mission.

  14. Verification and Validation of Model-Based Autonomous Systems

    NASA Technical Reports Server (NTRS)

    Pecheur, Charles; Koga, Dennis (Technical Monitor)

    2001-01-01

    This paper presents a three year project (FY99 to FY01) on the verification and validation of model based autonomous systems. The topics include: 1) Project Profile; 2) Model-Based Autonomy; 3) The Livingstone MIR; 4) MPL2SMV; 5) Livingstone to SMV Translation; 6) Symbolic Model Checking; 7) From Livingstone Models to SMV Models; 8) Application In-Situ Propellant Production; 9) Closed-Loop Verification Principle; 10) Livingstone PathFinder (LPF); 11) Publications and Presentations; and 12) Future Directions. This paper is presented in viewgraph form.

  15. A Model Based Mars Climate Database for the Mission Design

    NASA Technical Reports Server (NTRS)

    2005-01-01

    A viewgraph presentation on a model based climate database is shown. The topics include: 1) Why a model based climate database?; 2) Mars Climate Database v3.1 Who uses it ? (approx. 60 users!); 3) The new Mars Climate database MCD v4.0; 4) MCD v4.0: what's new ? 5) Simulation of Water ice clouds; 6) Simulation of Water ice cycle; 7) A new tool for surface pressure prediction; 8) Acces to the database MCD 4.0; 9) How to access the database; and 10) New web access

  16. Problem Solving: Physics Modeling-Based Interactive Engagement

    ERIC Educational Resources Information Center

    Ornek, Funda

    2009-01-01

    The purpose of this study was to investigate how modeling-based instruction combined with an interactive-engagement teaching approach promotes students' problem solving abilities. I focused on students in a calculus-based introductory physics course, based on the matter and interactions curriculum of Chabay & Sherwood (2002) at a large state…

  17. Cognitive control predicts use of model-based reinforcement learning.

    PubMed

    Otto, A Ross; Skatova, Anya; Madlon-Kay, Seth; Daw, Nathaniel D

    2015-02-01

    Accounts of decision-making and its neural substrates have long posited the operation of separate, competing valuation systems in the control of choice behavior. Recent theoretical and experimental work suggest that this classic distinction between behaviorally and neurally dissociable systems for habitual and goal-directed (or more generally, automatic and controlled) choice may arise from two computational strategies for reinforcement learning (RL), called model-free and model-based RL, but the cognitive or computational processes by which one system may dominate over the other in the control of behavior is a matter of ongoing investigation. To elucidate this question, we leverage the theoretical framework of cognitive control, demonstrating that individual differences in utilization of goal-related contextual information--in the service of overcoming habitual, stimulus-driven responses--in established cognitive control paradigms predict model-based behavior in a separate, sequential choice task. The behavioral correspondence between cognitive control and model-based RL compellingly suggests that a common set of processes may underpin the two behaviors. In particular, computational mechanisms originally proposed to underlie controlled behavior may be applicable to understanding the interactions between model-based and model-free choice behavior. PMID:25170791

  18. Product Lifecycle Management Architecture: A Model Based Systems Engineering Analysis.

    SciTech Connect

    Noonan, Nicholas James

    2015-07-01

    This report is an analysis of the Product Lifecycle Management (PLM) program. The analysis is centered on a need statement generated by a Nuclear Weapons (NW) customer. The need statement captured in this report creates an opportunity for the PLM to provide a robust service as a solution. Lifecycles for both the NW and PLM are analyzed using Model Based System Engineering (MBSE).

  19. Impact of Model-Based Teaching on Argumentation Skills

    ERIC Educational Resources Information Center

    Ogan-Bekiroglu, Feral; Belek, Deniz Eren

    2014-01-01

    The purpose of this study was to examine effects of model-based teaching on students' argumentation skills. Experimental design guided to the research. The participants of the study were pre-service physics teachers. The argumentative intervention lasted seven weeks. Data for this research were collected via video recordings and written…

  20. Applying knowledge compilation techniques to model-based reasoning

    NASA Technical Reports Server (NTRS)

    Keller, Richard M.

    1991-01-01

    Researchers in the area of knowledge compilation are developing general purpose techniques for improving the efficiency of knowledge-based systems. In this article, an attempt is made to define knowledge compilation, to characterize several classes of knowledge compilation techniques, and to illustrate how some of these techniques can be applied to improve the performance of model-based reasoning systems.

  1. Educational Value and Models-Based Practice in Physical Education

    ERIC Educational Resources Information Center

    Kirk, David

    2013-01-01

    A models-based approach has been advocated as a means of overcoming the serious limitations of the traditional approach to physical education. One of the difficulties with this approach is that physical educators have sought to use it to achieve diverse and sometimes competing educational benefits, and these wide-ranging aspirations are rarely if…

  2. Expediting model-based optoacoustic reconstructions with tomographic symmetries

    SciTech Connect

    Lutzweiler, Christian; Deán-Ben, Xosé Luís; Razansky, Daniel

    2014-01-15

    Purpose: Image quantification in optoacoustic tomography implies the use of accurate forward models of excitation, propagation, and detection of optoacoustic signals while inversions with high spatial resolution usually involve very large matrices, leading to unreasonably long computation times. The development of fast and memory efficient model-based approaches represents then an important challenge to advance on the quantitative and dynamic imaging capabilities of tomographic optoacoustic imaging. Methods: Herein, a method for simplification and acceleration of model-based inversions, relying on inherent symmetries present in common tomographic acquisition geometries, has been introduced. The method is showcased for the case of cylindrical symmetries by using polar image discretization of the time-domain optoacoustic forward model combined with efficient storage and inversion strategies. Results: The suggested methodology is shown to render fast and accurate model-based inversions in both numerical simulations andpost mortem small animal experiments. In case of a full-view detection scheme, the memory requirements are reduced by one order of magnitude while high-resolution reconstructions are achieved at video rate. Conclusions: By considering the rotational symmetry present in many tomographic optoacoustic imaging systems, the proposed methodology allows exploiting the advantages of model-based algorithms with feasible computational requirements and fast reconstruction times, so that its convenience and general applicability in optoacoustic imaging systems with tomographic symmetries is anticipated.

  3. Model-based diagnostics for Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Fesq, Lorraine M.; Stephan, Amy; Martin, Eric R.; Lerutte, Marcel G.

    1991-01-01

    An innovative approach to fault management was recently demonstrated for the NASA LeRC Space Station Freedom (SSF) power system testbed. This project capitalized on research in model-based reasoning, which uses knowledge of a system's behavior to monitor its health. The fault management system (FMS) can isolate failures online, or in a post analysis mode, and requires no knowledge of failure symptoms to perform its diagnostics. An in-house tool called MARPLE was used to develop and run the FMS. MARPLE's capabilities are similar to those available from commercial expert system shells, although MARPLE is designed to build model-based as opposed to rule-based systems. These capabilities include functions for capturing behavioral knowledge, a reasoning engine that implements a model-based technique known as constraint suspension, and a tool for quickly generating new user interfaces. The prototype produced by applying MARPLE to SSF not only demonstrated that model-based reasoning is a valuable diagnostic approach, but it also suggested several new applications of MARPLE, including an integration and testing aid, and a complement to state estimation.

  4. When Does Model-Based Control Pay Off?

    PubMed Central

    2016-01-01

    Many accounts of decision making and reinforcement learning posit the existence of two distinct systems that control choice: a fast, automatic system and a slow, deliberative system. Recent research formalizes this distinction by mapping these systems to “model-free” and “model-based” strategies in reinforcement learning. Model-free strategies are computationally cheap, but sometimes inaccurate, because action values can be accessed by inspecting a look-up table constructed through trial-and-error. In contrast, model-based strategies compute action values through planning in a causal model of the environment, which is more accurate but also more cognitively demanding. It is assumed that this trade-off between accuracy and computational demand plays an important role in the arbitration between the two strategies, but we show that the hallmark task for dissociating model-free and model-based strategies, as well as several related variants, do not embody such a trade-off. We describe five factors that reduce the effectiveness of the model-based strategy on these tasks by reducing its accuracy in estimating reward outcomes and decreasing the importance of its choices. Based on these observations, we describe a version of the task that formally and empirically obtains an accuracy-demand trade-off between model-free and model-based strategies. Moreover, we show that human participants spontaneously increase their reliance on model-based control on this task, compared to the original paradigm. Our novel task and our computational analyses may prove important in subsequent empirical investigations of how humans balance accuracy and demand. PMID:27564094

  5. Model-based Roentgen stereophotogrammetry of orthopaedic implants.

    PubMed

    Valstar, E R; de Jong, F W; Vrooman, H A; Rozing, P M; Reiber, J H

    2001-06-01

    Attaching tantalum markers to prostheses for Roentgen stereophotogrammetry (RSA) may be difficult and is sometimes even impossible. In this study, a model-based RSA method that avoids the attachment of markers to prostheses is presented and validated. This model-based RSA method uses a triangulated surface model of the implant. A projected contour of this model is calculated and this calculated model contour is matched onto the detected contour of the actual implant in the RSA radiograph. The difference between the two contours is minimized by variation of the position and orientation of the model. When a minimal difference between the contours is found, an optimal position and orientation of the model has been obtained. The method was validated by means of a phantom experiment. Three prosthesis components were used in this experiment: the femoral and tibial component of an Interax total knee prosthesis (Stryker Howmedica Osteonics Corp., Rutherfort, USA) and the femoral component of a Profix total knee prosthesis (Smith & Nephew, Memphis, USA). For the prosthesis components used in this study, the accuracy of the model-based method is lower than the accuracy of traditional RSA. For the Interax femoral and tibial components, significant dimensional tolerances were found that were probably caused by the casting process and manual polishing of the components surfaces. The largest standard deviation for any translation was 0.19mm and for any rotation it was 0.52 degrees. For the Profix femoral component that had no large dimensional tolerances, the largest standard deviation for any translation was 0.22mm and for any rotation it was 0.22 degrees. From this study we may conclude that the accuracy of the current model-based RSA method is sensitive to dimensional tolerances of the implant. Research is now being conducted to make model-based RSA less sensitive to dimensional tolerances and thereby improving its accuracy. PMID:11470108

  6. Non-linear control logics for vibrations suppression: a comparison between model-based and non-model-based techniques

    NASA Astrophysics Data System (ADS)

    Ripamonti, Francesco; Orsini, Lorenzo; Resta, Ferruccio

    2015-04-01

    Non-linear behavior is present in many mechanical system operating conditions. In these cases, a common engineering practice is to linearize the equation of motion around a particular operating point, and to design a linear controller. The main disadvantage is that the stability properties and validity of the controller are local. In order to improve the controller performance, non-linear control techniques represent a very attractive solution for many smart structures. The aim of this paper is to compare non-linear model-based and non-model-based control techniques. In particular the model-based sliding-mode-control (SMC) technique is considered because of its easy implementation and the strong robustness of the controller even under heavy model uncertainties. Among the non-model-based control techniques, the fuzzy control (FC), allowing designing the controller according to if-then rules, has been considered. It defines the controller without a system reference model, offering many advantages such as an intrinsic robustness. These techniques have been tested on the pendulum nonlinear system.

  7. Effective blockage of the interfacial recombination process at TiO(2) nanowire array electrodes in dye-sensitized solar cells.

    PubMed

    Jiang, Dianlu; Hao, Yuanqiang; Shen, Rujuan; Ghazarian, Sevak; Ramos, Angela; Zhou, Feimeng

    2013-11-27

    Effective blockage of recombination electron transfer of a fast electron transfer redox couple (ferrocenium/ferrocene or Fc(+)/Fc) at TiO2 nanowire array electrodes is achieved by silanization of the dye loaded TiO2 nanowire array. FT-IR clearly shows the formation of polysiloxane network at fluorine doped tin electrodes covered with TiO2 nanowire arrays and the dye molecules. Compared to the commonly used TiO2 nanoparticle film electrodes, the TiO2 nanowire array has a more spatially accessible structure, facilitating the formation of uniform polysiloxane films. Energy-dispersive X-ray spectroscopy (EDS) also reveals the presence of Si over multiple spots at the cross sections of the silanized TiO2 nanowire array electrodes. As a result, a rather high open-cell voltage Voc (0.69 V) and an enhanced efficiency (0.749 %) for DSSC with the Fc(+)/Fc couple were obtained. Contrary to the passivated TiO2 nanoparticle film electrodes at which a complex, biphasic dependence of electron lifetime on Voc was observed, we recorded a logarithm linear dependence of the lifetime on Voc after the silanization treatment. The nanowire arrays with optimal salinization treatments afford a useful surface for the study of electron recombination and photovoltaic generation in DSSCs. PMID:24191693

  8. Modeling and analysis framework for core damage propagation during flow-blockage-initiated accidents in the Advanced Neutron Source Reactor at Oak Ridge National Laboratory

    SciTech Connect

    Kim, S.H.; Taleyarkhan, R.P.; Navarro-Valenti, S.; Georgevich, V.

    1995-09-01

    This paper describes modeling and analysis to evaluate the extent of core damage during flow blockage events in the Advanced Neutron Source (ANS) reactor planned to be built at the Oak Ridge National Laboratory (ORNL). Damage propagation is postulated to occur from thermal conduction between damaged and undamaged plates due to direct thermal contact. Such direct thermal contact may occur because of fuel plate swelling during fission product vapor release or plate buckling. Complex phenomena of damage propagation were modeled using a one-dimensional heat transfer model. A scoping study was conducted to learn what parameters are important for core damage propagation, and to obtain initial estimates of core melt mass for addressing recriticality and steam explosion events. The study included investigating the effects of the plate contact area, the convective heat transfer coefficient, thermal conductivity upon fuel swelling, and the initial temperature of the plate being contacted by the damaged plate. Also, the side support plates were modeled to account for their effects on damage propagation. The results provide useful insights into how various uncertain parameters affect damage propagation.

  9. The Impact of Pituitary Blockage with GnRH Antagonist and Gonadotrophin Stimulation Length on The Outcome of ICSI Cycles in Women Older than 36 Years

    PubMed Central

    Santana, Rosane; Setti, Amanda Souza; Maldonado, Luiz Guilherme; Valente, Fernanda Montenegro; Iaconelli, Carla; Iaconelli Jr, Assumpto; Jr, Edson Borges

    2014-01-01

    Background The objective of this retrospective cohort study was to evaluate whether the length of pituitary blockage with gonadotrophin-releasing hormone (GnRH) antagonists or the stimulation period influence intracytoplasmic sperm injection (ICSI) outcomes in patients older than 36 years of age. Materials and Methods In this retrospective study, a total of 138 couples with maternal age >36 years undergoing ICSI with an antagonist protocol were included. The influences of stimulation and suppression length on the response to ovarian stimulation and ICSI outcomes were investigated. Receiver operating characteristic curve (ROC) analysis was performed to assess the predictive value of the stimulation period for achievement of implantation and pregnancy. Results The gonadotrophin stimulation length negatively influenced the implantation rate (RC: -4.200; p=0.023). The area under ROC curve (AUC) could distinguish between women with positive and negative implantation (AUC: 0.611; CI: 0.546-0.673) and pregnancy (AUC: 0.593; CI: 0.528-0.656). The threshold value demonstrated a high negative predictive value on likelihood of implantation (p=0.0032, 90% sensitivity) and pregnancy (p=0.0147, 87.1% sensitivity) when patients underwent more than 10 days of stimulation. Conclusion The stimulation period negatively influences the implantation rate in women older than 36 years. A stimulation interval greater than 10 days is associated with a negative predictive value for the chance of implantation and pregnancy. PMID:25083177

  10. The utilization of an infrared imaging system as a cooling slot blockage detector in the inspection of a transpiration cooled nozzle

    NASA Technical Reports Server (NTRS)

    Borg, Stephen E.; Wright, Robert E., Jr.; Alderfer, David W.; Whipple, Janet C.

    1990-01-01

    A comprehensive examination of the 8 foot temperature tunnel's transpiration cooled nozzle was completed using an infrared imaging radiometer to locate regions of cooling flow irregularities caused by obstruction of three or more adjacent cooling slots. Restrictions in the cooling flow were found and cataloged. Blockages found were due primarily to the presence of residual phosphoric acid being discharged from some of the cooling slots. This acid was used during construction of the nozzle components and was to have been purged prior to its delivery to the NASA Langley Research Center (LaRC). In addition, a radial displacement of one selection of discs located in the spool piece was inspected and cataloged for future reference. There did not seem to be a serious restriction of flow in this defect, but evidence from the infrared images indicated reduced slot activity within the gouge. The radiometer survey uncovered regions where closer inspection is recommended but did not cover the entire surface area of the three nozzle subsections due to equipment limitations. A list of areas with suspected problems is included in Appendix A.

  11. Sequential Bayesian Detection: A Model-Based Approach

    SciTech Connect

    Sullivan, E J; Candy, J V

    2007-08-13

    Sequential detection theory has been known for a long time evolving in the late 1940's by Wald and followed by Middleton's classic exposition in the 1960's coupled with the concurrent enabling technology of digital computer systems and the development of sequential processors. Its development, when coupled to modern sequential model-based processors, offers a reasonable way to attack physics-based problems. In this chapter, the fundamentals of the sequential detection are reviewed from the Neyman-Pearson theoretical perspective and formulated for both linear and nonlinear (approximate) Gauss-Markov, state-space representations. We review the development of modern sequential detectors and incorporate the sequential model-based processors as an integral part of their solution. Motivated by a wealth of physics-based detection problems, we show how both linear and nonlinear processors can seamlessly be embedded into the sequential detection framework to provide a powerful approach to solving non-stationary detection problems.

  12. Sequential Bayesian Detection: A Model-Based Approach

    SciTech Connect

    Candy, J V

    2008-12-08

    Sequential detection theory has been known for a long time evolving in the late 1940's by Wald and followed by Middleton's classic exposition in the 1960's coupled with the concurrent enabling technology of digital computer systems and the development of sequential processors. Its development, when coupled to modern sequential model-based processors, offers a reasonable way to attack physics-based problems. In this chapter, the fundamentals of the sequential detection are reviewed from the Neyman-Pearson theoretical perspective and formulated for both linear and nonlinear (approximate) Gauss-Markov, state-space representations. We review the development of modern sequential detectors and incorporate the sequential model-based processors as an integral part of their solution. Motivated by a wealth of physics-based detection problems, we show how both linear and nonlinear processors can seamlessly be embedded into the sequential detection framework to provide a powerful approach to solving non-stationary detection problems.

  13. Model based document and report generation for systems engineering

    NASA Astrophysics Data System (ADS)

    Delp, C.; Lam, D.; Fosse, E.; Lee, Cin-Young

    As Model Based Systems Engineering (MBSE) practices gain adoption, various approaches have been developed in order to simplify and automate the process of generating documents from models. Essentially, all of these techniques can be unified around the concept of producing different views of the model according to the needs of the intended audience. In this paper, we will describe a technique developed at JPL of applying SysML Viewpoints and Views to generate documents and reports. An architecture of model-based view and document generation will be presented, and the necessary extensions to SysML with associated rationale will be explained. A survey of examples will highlight a variety of views that can be generated, and will provide some insight into how collaboration and integration is enabled. We will also describe the basic architecture for the enterprise applications that support this approach.

  14. Fusing Quantitative Requirements Analysis with Model-based Systems Engineering

    NASA Technical Reports Server (NTRS)

    Cornford, Steven L.; Feather, Martin S.; Heron, Vance A.; Jenkins, J. Steven

    2006-01-01

    A vision is presented for fusing quantitative requirements analysis with model-based systems engineering. This vision draws upon and combines emergent themes in the engineering milieu. "Requirements engineering" provides means to explicitly represent requirements (both functional and non-functional) as constraints and preferences on acceptable solutions, and emphasizes early-lifecycle review, analysis and verification of design and development plans. "Design by shopping" emphasizes revealing the space of options available from which to choose (without presuming that all selection criteria have previously been elicited), and provides means to make understandable the range of choices and their ramifications. "Model-based engineering" emphasizes the goal of utilizing a formal representation of all aspects of system design, from development through operations, and provides powerful tool suites that support the practical application of these principles. A first step prototype towards this vision is described, embodying the key capabilities. Illustrations, implications, further challenges and opportunities are outlined.

  15. Model-based hierarchical reinforcement learning and human action control

    PubMed Central

    Botvinick, Matthew; Weinstein, Ari

    2014-01-01

    Recent work has reawakened interest in goal-directed or ‘model-based’ choice, where decisions are based on prospective evaluation of potential action outcomes. Concurrently, there has been growing attention to the role of hierarchy in decision-making and action control. We focus here on the intersection between these two areas of interest, considering the topic of hierarchical model-based control. To characterize this form of action control, we draw on the computational framework of hierarchical reinforcement learning, using this to interpret recent empirical findings. The resulting picture reveals how hierarchical model-based mechanisms might play a special and pivotal role in human decision-making, dramatically extending the scope and complexity of human behaviour. PMID:25267822

  16. Model-based decision support in diabetes care.

    PubMed

    Salzsieder, E; Vogt, L; Kohnert, K-D; Heinke, P; Augstein, P

    2011-05-01

    The model-based Karlsburg Diabetes Management System (KADIS®) has been developed as a patient-focused decision-support tool to provide evidence-based advice for physicians in their daily efforts to optimize metabolic control in diabetes care of their patients on an individualized basis. For this purpose, KADIS® was established in terms of a personalized, interactive in silico simulation procedure, implemented into a problem-related diabetes health care network and evaluated under different conditions by conducting open-label mono- and polycentric trials, and a case-control study, and last but not least, by application in routine diabetes outpatient care. The trial outcomes clearly show that the recommendations provided to the physicians by KADIS® lead to significant improvement of metabolic control. This model-based decision-support system provides an excellent tool to effectively guide physicians in personalized decision-making to achieve optimal metabolic control for their patients. PMID:20621384

  17. Adaptive, Model-Based Monitoring and Threat Detection

    NASA Astrophysics Data System (ADS)

    Valdes, Alfonso; Skinner, Keith

    2002-09-01

    We explore the suitability of model-based probabilistic techniques, such as Bayes networks, to the field of intrusion detection and alert report correlation. We describe a network intrusion detection system (IDS) using Bayes inference, wherein the knowledge base is encoded not as rules but as conditional probability relations between observables and hypotheses of normal and malicious usage. The same high-performance Bayes inference library was employed in a component of the Mission-Based Correlation effort, using an initial knowledge base that adaptively learns the security administrator's preference for alert priority and rank. Another major effort demonstrated probabilistic techniques in heterogeneous sensor correlation. We provide results for simulated attack data, live traffic, and the CyberPanel Grand Challenge Problem. Our results establish that model-based probabilistic techniques are an important complementary capability to signature-based methods in detection and correlation.

  18. Hierarchical model-based interferometric synthetic aperture radar image registration

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Huang, Haifeng; Dong, Zhen; Wu, Manqing

    2014-01-01

    With the rapid development of spaceborne interferometric synthetic aperture radar technology, classical image registration methods are incompetent for high-efficiency and high-accuracy masses of real data processing. Based on this fact, we propose a new method. This method consists of two steps: coarse registration that is realized by cross-correlation algorithm and fine registration that is realized by hierarchical model-based algorithm. Hierarchical model-based algorithm is a high-efficiency optimization algorithm. The key features of this algorithm are a global model that constrains the overall structure of the motion estimated, a local model that is used in the estimation process, and a coarse-to-fine refinement strategy. Experimental results from different kinds of simulated and real data have confirmed that the proposed method is very fast and has high accuracy. Comparing with a conventional cross-correlation method, the proposed method provides markedly improved performance.

  19. Model Based Document and Report Generation for Systems Engineering

    NASA Technical Reports Server (NTRS)

    Delp, Christopher; Lam, Doris; Fosse, Elyse; Lee, Cin-Young

    2013-01-01

    As Model Based Systems Engineering (MBSE) practices gain adoption, various approaches have been developed in order to simplify and automate the process of generating documents from models. Essentially, all of these techniques can be unified around the concept of producing different views of the model according to the needs of the intended audience. In this paper, we will describe a technique developed at JPL of applying SysML Viewpoints and Views to generate documents and reports. An architecture of model-based view and document generation will be presented, and the necessary extensions to SysML with associated rationale will be explained. A survey of examples will highlight a variety of views that can be generated, and will provide some insight into how collaboration and integration is enabled. We will also describe the basic architecture for the enterprise applications that support this approach.

  20. 3-D model-based tracking for UAV indoor localization.

    PubMed

    Teulière, Céline; Marchand, Eric; Eck, Laurent

    2015-05-01

    This paper proposes a novel model-based tracking approach for 3-D localization. One main difficulty of standard model-based approach lies in the presence of low-level ambiguities between different edges. In this paper, given a 3-D model of the edges of the environment, we derive a multiple hypotheses tracker which retrieves the potential poses of the camera from the observations in the image. We also show how these candidate poses can be integrated into a particle filtering framework to guide the particle set toward the peaks of the distribution. Motivated by the UAV indoor localization problem where GPS signal is not available, we validate the algorithm on real image sequences from UAV flights. PMID:25099967

  1. Model-based inversion for a shallow ocean application

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1994-03-01

    A model-based approach to invert or estimate the sound speed profile (SSP) from noisy pressure-field measurements is discussed. The resulting model-based processor (MBP) is based on the state-space representation of the normal-mode propagation model. Using data obtained from the well-known Hudson Canyon experiment, a noisy shallow water ocean environment, the processor is designed and the results compared to those predicted using various propagation models and data. It is shown that the MBP not only predicts the sound speed quite well, but also is able to simultaneously provide enhanced estimates of both modal and pressure-field measurements which are useful for localization and rapid ocean environmental characterization.

  2. Automated extraction of knowledge for model-based diagnostics

    NASA Technical Reports Server (NTRS)

    Gonzalez, Avelino J.; Myler, Harley R.; Towhidnejad, Massood; Mckenzie, Frederic D.; Kladke, Robin R.

    1990-01-01

    The concept of accessing computer aided design (CAD) design databases and extracting a process model automatically is investigated as a possible source for the generation of knowledge bases for model-based reasoning systems. The resulting system, referred to as automated knowledge generation (AKG), uses an object-oriented programming structure and constraint techniques as well as internal database of component descriptions to generate a frame-based structure that describes the model. The procedure has been designed to be general enough to be easily coupled to CAD systems that feature a database capable of providing label and connectivity data from the drawn system. The AKG system is capable of defining knowledge bases in formats required by various model-based reasoning tools.

  3. Identifying Model-Based Reconfiguration Goals through Functional Deficiencies

    NASA Technical Reports Server (NTRS)

    Benazera, Emmanuel; Trave-Massuyes, Louise

    2004-01-01

    Model-based diagnosis is now advanced to the point autonomous systems face some uncertain and faulty situations with success. The next step toward more autonomy is to have the system recovering itself after faults occur, a process known as model-based reconfiguration. After faults occur, given a prediction of the nominal behavior of the system and the result of the diagnosis operation, this paper details how to automatically determine the functional deficiencies of the system. These deficiencies are characterized in the case of uncertain state estimates. A methodology is then presented to determine the reconfiguration goals based on the deficiencies. Finally, a recovery process interleaves planning and model predictive control to restore the functionalities in prioritized order.

  4. Fuzzy model-based observers for fault detection in CSTR.

    PubMed

    Ballesteros-Moncada, Hazael; Herrera-López, Enrique J; Anzurez-Marín, Juan

    2015-11-01

    Under the vast variety of fuzzy model-based observers reported in the literature, what would be the properone to be used for fault detection in a class of chemical reactor? In this study four fuzzy model-based observers for sensor fault detection of a Continuous Stirred Tank Reactor were designed and compared. The designs include (i) a Luenberger fuzzy observer, (ii) a Luenberger fuzzy observer with sliding modes, (iii) a Walcott-Zak fuzzy observer, and (iv) an Utkin fuzzy observer. A negative, an oscillating fault signal, and a bounded random noise signal with a maximum value of ±0.4 were used to evaluate and compare the performance of the fuzzy observers. The Utkin fuzzy observer showed the best performance under the tested conditions. PMID:26521723

  5. Model based control of a rehabilitation robot for lower extremities.

    PubMed

    Xie, Xiao-Liang; Hou, Zeng-Guang; Li, Peng-Feng; Ji, Cheng; Zhang, Feng; Tan, Min; Wang, Hongbo; Hu, Guoqing

    2010-01-01

    This paper mainly focuses on the trajectory tracking control of a lower extremity rehabilitation robot during passive training process of patients. Firstly, a mathematical model of the rehabilitation robot is introduced by using Lagrangian analysis. Then, a model based computed-torque control scheme is designed to control the constrained four-link robot (with patient's foot fixed on robot's end-effector) to track a predefined trajectory. Simulation results are provided to illustrate the effectiveness of the proposed model based computed-torque algorithm. In the simulation, a multi-body dynamics and motion software named ADAMS is used. The combined simulation of ADAMS and MATLAB is able to produce more realistic results of this complex integrated system. PMID:21097222

  6. REAL-TIME MODEL-BASED ELECTRICAL POWERED WHEELCHAIR CONTROL

    PubMed Central

    Wang, Hongwu; Salatin, Benjamin; Grindle, Garrett G.; Ding, Dan; Cooper, Rory A.

    2009-01-01

    The purpose of this study was to evaluate the effects of three different control methods on driving speed variation and wheel-slip of an electric-powered wheelchair (EPW). A kinematic model as well as 3-D dynamic model was developed to control the velocity and traction of the wheelchair. A smart wheelchair platform was designed and built with a computerized controller and encoders to record wheel speeds and to detect the slip. A model based, a proportional-integral-derivative (PID) and an open-loop controller were applied with the EPW driving on four different surfaces at three specified speeds. The speed errors, variation, rise time, settling time and slip coefficient were calculated and compared for a speed step-response input. Experimental results showed that model based control performed best on all surfaces across the speeds. PMID:19733494

  7. MTK: An AI tool for model-based reasoning

    NASA Technical Reports Server (NTRS)

    Erickson, William K.; Schwartz, Mary R.

    1987-01-01

    A 1988 goal for the Systems Autonomy Demonstration Project Office of the NASA Ames Research Center is to apply model-based representation and reasoning techniques in a knowledge-based system that will provide monitoring, fault diagnosis, control and trend analysis of the space station Thermal Management System (TMS). A number of issues raised during the development of the first prototype system inspired the design and construction of a model-based reasoning tool called MTK, which was used in the building of the second prototype. These issues are outlined, along with examples from the thermal system to highlight the motivating factors behind them. An overview of the capabilities of MTK is given.

  8. Model-Based Detection in a Shallow Water Ocean Environment

    SciTech Connect

    Candy, J V

    2001-07-30

    A model-based detector is developed to process shallow water ocean acoustic data. The function of the detector is to adaptively monitor the environment and decide whether or not a change from normal has occurred. Here we develop a processor incorporating both a normal-mode ocean acoustic model and a vertical hydrophone array. The detector is applied to data acquired from the Hudson Canyon experiments at various ranges and its performance is evaluated.

  9. Applying Model Based Systems Engineering to NASA's Space Communications Networks

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul; Barnes, Patrick; Reinert, Jessica; Golden, Bert

    2013-01-01

    System engineering practices for complex systems and networks now require that requirement, architecture, and concept of operations product development teams, simultaneously harmonize their activities to provide timely, useful and cost-effective products. When dealing with complex systems of systems, traditional systems engineering methodology quickly falls short of achieving project objectives. This approach is encumbered by the use of a number of disparate hardware and software tools, spreadsheets and documents to grasp the concept of the network design and operation. In case of NASA's space communication networks, since the networks are geographically distributed, and so are its subject matter experts, the team is challenged to create a common language and tools to produce its products. Using Model Based Systems Engineering methods and tools allows for a unified representation of the system in a model that enables a highly related level of detail. To date, Program System Engineering (PSE) team has been able to model each network from their top-level operational activities and system functions down to the atomic level through relational modeling decomposition. These models allow for a better understanding of the relationships between NASA's stakeholders, internal organizations, and impacts to all related entities due to integration and sustainment of existing systems. Understanding the existing systems is essential to accurate and detailed study of integration options being considered. In this paper, we identify the challenges the PSE team faced in its quest to unify complex legacy space communications networks and their operational processes. We describe the initial approaches undertaken and the evolution toward model based system engineering applied to produce Space Communication and Navigation (SCaN) PSE products. We will demonstrate the practice of Model Based System Engineering applied to integrating space communication networks and the summary of its

  10. Model-based rational strategy for chromatographic resin selection.

    PubMed

    Nfor, Beckley K; Zuluaga, Diego S; Verheijen, Peter J T; Verhaert, Peter D E M; van der Wielen, Luuk A M; Ottens, Marcel

    2011-01-01

    A model-based rational strategy for the selection of chromatographic resins is presented. The main question being addressed is that of selecting the most optimal chromatographic resin from a few promising alternatives. The methodology starts with chromatographic modeling,parameters acquisition, and model validation, followed by model-based optimization of the chromatographic separation for the resins of interest. Finally, the resins are rationally evaluated based on their optimized operating conditions and performance metrics such as product purity, yield, concentration, throughput, productivity, and cost. Resin evaluation proceeds by two main approaches. In the first approach, Pareto frontiers from multi-objective optimization of conflicting objectives are overlaid for different resins, enabling direct visualization and comparison of resin performances based on the feasible solution space. The second approach involves the transformation of the resin performances into weighted resin scores, enabling the simultaneous consideration of multiple performance metrics and the setting of priorities. The proposed model-based resin selection strategy was illustrated by evaluating three mixed mode adsorbents (ADH, PPA, and HEA) for the separation of a ternary mixture of bovine serum albumin, ovalbumin, and amyloglucosidase. In order of decreasing weighted resin score or performance, the top three resins for this separation were ADH [PPA[HEA. The proposed model-based approach could be a suitable alternative to column scouting during process development, the main strengths being that minimal experimentation is required and resins are evaluated under their ideal working conditions, enabling a fair comparison. This work also demonstrates the application of column modeling and optimization to mixed mode chromatography. PMID:22238769

  11. On Environmental Model-Based Visual Perception for Humanoids

    NASA Astrophysics Data System (ADS)

    Gonzalez-Aguirre, D.; Wieland, S.; Asfour, T.; Dillmann, R.

    In this article an autonomous visual perception framework for humanoids is presented. This model-based framework exploits the available knowledge and the context acquired during global localization in order to overcome the limitations of pure data-driven approaches. The reasoning for perception and the properceptive components are the key elements to solve complex visual assertion queries with a proficient performance. Experimental evaluation with the humanoid robot ARMAR-IIIa is presented.

  12. Model based control of dynamic atomic force microscope

    SciTech Connect

    Lee, Chibum; Salapaka, Srinivasa M.

    2015-04-15

    A model-based robust control approach is proposed that significantly improves imaging bandwidth for the dynamic mode atomic force microscopy. A model for cantilever oscillation amplitude and phase dynamics is derived and used for the control design. In particular, the control design is based on a linearized model and robust H{sub ∞} control theory. This design yields a significant improvement when compared to the conventional proportional-integral designs and verified by experiments.

  13. Model based control of dynamic atomic force microscope.

    PubMed

    Lee, Chibum; Salapaka, Srinivasa M

    2015-04-01

    A model-based robust control approach is proposed that significantly improves imaging bandwidth for the dynamic mode atomic force microscopy. A model for cantilever oscillation amplitude and phase dynamics is derived and used for the control design. In particular, the control design is based on a linearized model and robust H(∞) control theory. This design yields a significant improvement when compared to the conventional proportional-integral designs and verified by experiments. PMID:25933864

  14. Multiple Damage Progression Paths in Model-Based Prognostics

    NASA Technical Reports Server (NTRS)

    Daigle, Matthew; Goebel, Kai Frank

    2011-01-01

    Model-based prognostics approaches employ domain knowledge about a system, its components, and how they fail through the use of physics-based models. Component wear is driven by several different degradation phenomena, each resulting in their own damage progression path, overlapping to contribute to the overall degradation of the component. We develop a model-based prognostics methodology using particle filters, in which the problem of characterizing multiple damage progression paths is cast as a joint state-parameter estimation problem. The estimate is represented as a probability distribution, allowing the prediction of end of life and remaining useful life within a probabilistic framework that supports uncertainty management. We also develop a novel variance control mechanism that maintains an uncertainty bound around the hidden parameters to limit the amount of estimation uncertainty and, consequently, reduce prediction uncertainty. We construct a detailed physics-based model of a centrifugal pump, to which we apply our model-based prognostics algorithms. We illustrate the operation of the prognostic solution with a number of simulation-based experiments and demonstrate the performance of the chosen approach when multiple damage mechanisms are active

  15. A Model-Based Prognostics Approach Applied to Pneumatic Valves

    NASA Technical Reports Server (NTRS)

    Daigle, Matthew J.; Goebel, Kai

    2011-01-01

    Within the area of systems health management, the task of prognostics centers on predicting when components will fail. Model-based prognostics exploits domain knowledge of the system, its components, and how they fail by casting the underlying physical phenomena in a physics-based model that is derived from first principles. Uncertainty cannot be avoided in prediction, therefore, algorithms are employed that help in managing these uncertainties. The particle filtering algorithm has become a popular choice for model-based prognostics due to its wide applicability, ease of implementation, and support for uncertainty management. We develop a general model-based prognostics methodology within a robust probabilistic framework using particle filters. As a case study, we consider a pneumatic valve from the Space Shuttle cryogenic refueling system. We develop a detailed physics-based model of the pneumatic valve, and perform comprehensive simulation experiments to illustrate our prognostics approach and evaluate its effectiveness and robustness. The approach is demonstrated using historical pneumatic valve data from the refueling system.

  16. A Model-Based Expert System For Digital Systems Design

    NASA Astrophysics Data System (ADS)

    Wu, J. G.; Ho, W. P. C.; Hu, Y. H.; Yun, D. Y. Y.; Parng, T. M.

    1987-05-01

    In this paper, we present a model-based expert system for automatic digital systems design. The goal of digital systems design is to generate a workable and efficient design from high level specifications. The formalization of the design process is a necessity for building an efficient automatic CAD system. Our approach combines model-based, heuristic best-first search, and meta-planning techniques from AI to facilitate the design process. The design process is decomposed into three subprocesses. First, the high-level behavioral specifications are translated into sequences of primitive behavioral operations. Next, primitive operations are grouped to form intermediate-level behavioral functions. Finally, structural function modules are selected to implement these functions. Using model-based reasoning on the primitive behavioral operations level extends the solution space considered in design and provides more opportunity for minimization. Heuristic best-first search and meta-planning tech-niques control the decision-making in the latter two subprocesses to optimize the final design. They also facilitate system maintenance by separating design strategy from design knowledge.

  17. A cloud model-based approach for water quality assessment.

    PubMed

    Wang, Dong; Liu, Dengfeng; Ding, Hao; Singh, Vijay P; Wang, Yuankun; Zeng, Xiankui; Wu, Jichun; Wang, Lachun

    2016-07-01

    Water quality assessment entails essentially a multi-criteria decision-making process accounting for qualitative and quantitative uncertainties and their transformation. Considering uncertainties of randomness and fuzziness in water quality evaluation, a cloud model-based assessment approach is proposed. The cognitive cloud model, derived from information science, can realize the transformation between qualitative concept and quantitative data, based on probability and statistics and fuzzy set theory. When applying the cloud model to practical assessment, three technical issues are considered before the development of a complete cloud model-based approach: (1) bilateral boundary formula with nonlinear boundary regression for parameter estimation, (2) hybrid entropy-analytic hierarchy process technique for calculation of weights, and (3) mean of repeated simulations for determining the degree of final certainty. The cloud model-based approach is tested by evaluating the eutrophication status of 12 typical lakes and reservoirs in China and comparing with other four methods, which are Scoring Index method, Variable Fuzzy Sets method, Hybrid Fuzzy and Optimal model, and Neural Networks method. The proposed approach yields information concerning membership for each water quality status which leads to the final status. The approach is found to be representative of other alternative methods and accurate. PMID:26995351

  18. Experimental evaluation of blockage ratio and plenum evacuation system flow effects on pressure distribution for bodies of revolution in 0.1 scale model test section of NASA Lewis Research Center's proposed altitude wind tunnel

    NASA Technical Reports Server (NTRS)

    Burley, Richard R.; Harrington, Douglas E.

    1987-01-01

    An experimental investigation was conducted in the slotted test section of the 0.1-scale model of the proposed Altitude Wind Tunnel to evaluate wall interference effects at tunnel Mach numbers from 0.70 to 0.95 on bodies of revolution with blockage rates of 0.43, 3, 6, and 12 percent. The amount of flow that had to be removed from the plenum chamber (which surrounded the slotted test section) by the plenum evacuation system (PES) to eliminate wall interference effects was determined. The effectiveness of tunnel reentry flaps in removing flow from the plenum chamber was examined. The 0.43-percent blockage model was the only one free of wall interference effects with no PES flow. Surface pressures on the forward part of the other models were greater than interference-free results and were not influenced by PES flow. Interference-free results were achieved on the aft part of the 3- and 6-percent blockage models with the proper amount of PES flow. The required PES flow was substantially reduced by opening the reentry flaps.

  19. High-order Hybridized Discontinuous Galerkin (HDG) method for wave propagation simulation in complex geophysical media (elastic, acoustic and hydro-acoustic); an unifying framework to couple continuous Spectral Element and Discontinuous Galerkin Methods

    NASA Astrophysics Data System (ADS)

    Terrana, Sebastien; Vilotte, Jean-Pierre; Guillot, Laurent; Mariotti, Christian

    2015-04-01

    Today seismological observation systems combine broadband seismic receivers, hydrophones and micro-barometers antenna that provide complementary observations of source-radiated waves in heterogeneous and complex geophysical media. Exploiting these observations requires accurate and multi-physics - elastic, hydro-acoustic, infrasonic - wave simulation methods. A popular approach is the Spectral Element Method (SEM) (Chaljub et al, 2006) which is high-order accurate (low dispersion error), very flexible to parallelization and computationally attractive due to efficient sum factorization technique and diagonal mass matrix. However SEMs suffer from lack of flexibility in handling complex geometry and multi-physics wave propagation. High-order Discontinuous Galerkin Methods (DGMs), i.e. Dumbser et al (2006), Etienne et al. (2010), Wilcox et al (2010), are recent alternatives that can handle complex geometry, space-and-time adaptativity, and allow efficient multi-physics wave coupling at interfaces. However, DGMs are more memory demanding and less computationally attractive than SEMs, especially when explicit time stepping is used. We propose a new class of higher-order Hybridized Discontinuous Galerkin Spectral Elements (HDGSEM) methods for spatial discretization of wave equations, following the unifying framework for hybridization of Cockburn et al (2009) and Nguyen et al (2011), which allows for a single implementation of conforming and non-conforming SEMs. When used with energy conserving explicit time integration schemes, HDGSEM is flexible to handle complex geometry, computationally attractive and has significantly less degrees of freedom than classical DGMs, i.e., the only coupled unknowns are the single-valued numerical traces of the velocity field on the element's faces. The formulation can be extended to model fractional energy loss at interfaces between elastic, acoustic and hydro-acoustic media. Accuracy and performance of the HDGSEM are illustrated and

  20. Sorption of TCE by humic-preloaded activated carbon: Incorporating size-exclusion and pore blockage phenomenon in a competitive adsorption model

    SciTech Connect

    Kilduff, J.E.; Wigton, A.

    1999-01-15

    Naturally occurring, macromolecular dissolved organic matter (NOM) is known to foul activated carbon adsorbents, reducing the ability of fixed-bed adsorbers to efficiently remove targeted synthetic organic contaminants (SOCs). An accurate description of the effects of NOM competition on SOC adsorption equilibria is required to develop dynamic models, which have application to process design and analysis. A model was developed, using an approach based on the Ideal Adsorbed Solution Theory (IAST), to predict trichloroethylene (TCE) adsorption by activated carbon preloaded with humic acid. The IAST model was formulated for a bisolute system in which TCE and humic acid single-solute uptakes were described by the Langmuir-Freundlich and Freundlich isotherms, respectively. The humic mixture was modeled as a single component based on previous studies that identified the low-molecular-weight hydrophobic fraction as the most reactive with regard to preloading effects. Isotherms for this fraction, isolated from whole humic acid using ultrafiltration, were measured, and molar concentrations were computed based on an average molecular weight determined using size-exclusion chromatography. The IAST model was modified to reflect the hypothesis that TCE molecules can access adsorption sites which humic molecules cannot and that no competition can occur on these sites. The model was calibrated with data for TCE uptake by carbon preloaded with the low-molecular-weight humic acid fraction and was verified by predicting TCE uptake by carbon preloaded with whole humic acid. Further improvement to the model was possible by accounting for pore blockage as a mechanism which can reduce the effective surface area available in TCE.

  1. Blockage of Src by Specific siRNA as a Novel Therapeutic Strategy to Prevent Destructive Repair in Steroid-Associated Osteonecrosis in Rabbits.

    PubMed

    Zheng, Li-zhen; Cao, Hui-juan; Chen, Shi-hui; Tang, Tao; Fu, Wei-min; Huang, Le; Chow, Dick Ho Kiu; Wang, Yi-xiang; Griffith, James Francis; He, Wei; Zhou, Hong; Zhao, De-wei; Zhang, Ge; Wang, Xin-luan; Qin, Ling

    2015-11-01

    Vascular hyperpermeability and highly upregulated bone resorption in the destructive repair progress of steroid-associated osteonecrosis (SAON) are associated with a high expression of VEGF and high Src activity (Src is encoded by the cellular sarcoma [c-src] gene). This study was designed to prove our hypothesis that blocking the VEGF-Src signaling pathway by specific Src siRNA is able to prevent destructive repair in a SAON rabbit model. Destructive repair in SAON was induced in rabbits. At 2, 4, and 6 weeks after SAON induction, VEGF, anti-VEGF, Src siRNA, Src siRNA+VEGF, control siRNA, and saline were introduced via intramedullary injection into proximal femora for each group, respectively. Vascularization and permeability were quantified by dynamic contrast-enhanced (DCE) MRI. At week 6 after SAON induction, proximal femurs were dissected for micro-computed tomography (μCT)-based trabecular architecture with finite element analysis (FEA), μCT-based angiography, and histological analysis. Histological evaluation revealed that VEGF enhanced destructive repair, whereas anti-VEGF prevented destructive repair and Src siRNA and Src siRNA+VEGF prevented destructive repair and enhanced reparative osteogenesis. Findings of angiography and histomorphometry were consistent with those determined by DCE MRI. Src siRNA inhibited VEGF-mediated vascular hyperpermeability but preserved VEGF-induced neovascularization. Bone resorption was enhanced in the VEGF group and inhibited in the anti-VEGF, Src siRNA, Src siRNA+VEGF groups as determined by both 3D μCT and 2D histomorphometry. FEA showed higher estimated failure load in the Src siRNA and Src siRNA+VEGF groups when compared to the vehicle control group. Blockage of VEGF-Src signaling pathway by specific Src siRNA was able to prevent steroid-associated destructive repair while improving reconstructive repair in SAON, which might become a novel therapeutic strategy. PMID:25917347

  2. Spinal blockage of P/Q- or N-type voltage-gated calcium channels modulates functional and symptomatic changes related to haemorrhagic cystitis in mice

    PubMed Central

    Silva, R B M; Sperotto, N D M; Andrade, E L; Pereira, T C B; Leite, C E; de Souza, A H; Bogo, M R; Morrone, F B; Gomez, M V; Campos, M M

    2015-01-01

    Background and Purpose Spinal voltage-gated calcium channels (VGCCs) are pivotal regulators of painful and inflammatory alterations, representing attractive therapeutic targets. We examined the effects of epidural administration of the P/Q- and N-type VGCC blockers Tx3-3 and Phα1β, respectively, isolated from the spider Phoneutria nigriventer, on symptomatic, inflammatory and functional changes allied to mouse cyclophosphamide (CPA)-induced haemorrhagic cystitis (HC). The effects of P. nigriventer-derived toxins were compared with those displayed by MVIIC and MVIIA, extracted from the cone snail Conus magus. Experimental Approach HC was induced by a single i.p. injection of CPA (300 mg·kg–1). Dose- and time-related effects of spinally administered P/Q and N-type VGCC blockers were assessed on nociceptive behaviour and macroscopic inflammation elicited by CPA. The effects of toxins were also evaluated on cell migration, cytokine production, oxidative stress, functional cystometry alterations and TRPV1, TRPA1 and NK1 receptor mRNA expression. Key Results The spinal blockage of P/Q-type VGCC by Tx3-3 and MVIIC or N-type VGCC by Phα1β attenuated nociceptive and inflammatory events associated with HC, including bladder oxidative stress and cytokine production. CPA produced a slight increase in bladder TRPV1 and TRPA1 mRNA expression, which was reversed by all the toxins tested. Noteworthy, Phα1β strongly prevented bladder neutrophil migration, besides HC-related functional alterations, and its effects were potentiated by co-injecting the selective NK1 receptor antagonist CP-96345. Conclusions and Implications Our results shed new light on the role of spinal P/Q and N-type VGCC in bladder dysfunctions, pointing out Phα1β as a promising alternative for treating complications associated with CPA-induced HC. PMID:25298144

  3. PCR-Independent Detection of Bacterial Species-Specific 16S rRNA at 10 fM by a Pore-Blockage Sensor.

    PubMed

    Esfandiari, Leyla; Wang, Siqing; Wang, Siqi; Banda, Anisha; Lorenzini, Michael; Kocharyan, Gayane; Monbouquette, Harold G; Schmidt, Jacob J

    2016-01-01

    A PCR-free, optics-free device is used for the detection of Escherichia coli (E. coli) 16S rRNA at 10 fM, which corresponds to ~100-1000 colony forming units/mL (CFU/mL) depending on cellular rRNA levels. The development of a rapid, sensitive, and cost-effective nucleic acid detection platform is sought for the detection of pathogenic microbes in food, water and body fluids. Since 16S rRNA sequences are species specific and are present at high copy number in viable cells, these nucleic acids offer an attractive target for microbial pathogen detection schemes. Here, target 16S rRNA of E. coli at 10 fM concentration was detected against a total RNA background using a conceptually simple approach based on electromechanical signal transduction, whereby a step change reduction in ionic current through a pore indicates blockage by an electrophoretically mobilized bead-peptide nucleic acid probe conjugate hybridized to target nucleic acid. We investigated the concentration detection limit for bacterial species-specific 16S rRNA at 1 pM to 1 fM and found a limit of detection of 10 fM for our device, which is consistent with our previous finding with single-stranded DNA of similar length. In addition, no false positive responses were obtained with control RNA and no false negatives with target 16S rRNA present down to the limit of detection (LOD) of 10 fM. Thus, this detection scheme shows promise for integration into portable, low-cost systems for rapid detection of pathogenic microbes in food, water and body fluids. PMID:27455337

  4. Model based control of polymer composite manufacturing processes

    NASA Astrophysics Data System (ADS)

    Potaraju, Sairam

    2000-10-01

    The objective of this research is to develop tools that help process engineers design, analyze and control polymeric composite manufacturing processes to achieve higher productivity and cost reduction. Current techniques for process design and control of composite manufacturing suffer from the paucity of good process models that can accurately represent these non-linear systems. Existing models developed by researchers in the past are designed to be process and operation specific, hence generating new simulation models is time consuming and requires significant effort. To address this issue, an Object Oriented Design (OOD) approach is used to develop a component-based model building framework. Process models for two commonly used industrial processes (Injected Pultrusion and Autoclave Curing) are developed using this framework to demonstrate the flexibility. Steady state and dynamic validation of this simulator is performed using a bench scale injected pultrusion process. This simulator could not be implemented online for control due to computational constraints. Models that are fast enough for online implementation, with nearly the same degree of accuracy are developed using a two-tier scheme. First, lower dimensional models that captures essential resin flow, heat transfer and cure kinetics important from a process monitoring and control standpoint are formulated. The second step is to reduce these low dimensional models to Reduced Order Models (ROM) suited for online model based estimation, control and optimization. Model reduction is carried out using Proper Orthogonal Decomposition (POD) technique in conjunction with a Galerkin formulation procedure. Subsequently, a nonlinear model-based estimation and inferential control scheme based on the ROM is implemented. In particular, this research work contributes in the following general areas: (1) Design and implementation of versatile frameworks for modeling and simulation of manufacturing processes using object

  5. Broadband model-based processing for shallow ocean environments

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1998-07-01

    Most acoustic sources found in the ocean environment are spatially complex and broadband. In the case of shallow water propagation, these source characteristics complicate the analysis of received acoustic data considerably. A common approach to the broadband problem is to decompose the received signal into a set of narrow-band lines. This then allows the problem to be treated as a multiplicity of narrow-band problems. Here a model-based approach is developed for the processing of data received on a vertical array from a broadband source where it is assumed that the propagation is governed by the normal-mode model. The goal of the processor is to provide an enhanced (filtered) version of the pressure at the array and the modal functions. Thus a pre-processor is actually developed, since one could think of several applications for these enhanced quantities such as localization, modal estimation, etc. It is well-known that in normal-mode theory a different modal structure evolves for each temporal frequency; thus it is not surprising that the model-based solution to this problem results in a scheme that requires a {open_quotes}bank{close_quotes} of narrow-band model-based processors{emdash}each with its own underlying modal structure for the narrow frequency band it operates over. The {open_quotes}optimal{close_quotes} Bayesian solution to the broadband pressure field enhancement and modal function extraction problem is developed. It is shown how this broadband processor can be implemented (using a suboptimal scheme) in pseudo real time due to its inherent parallel structure. A set of noisy broadband data is synthesized to demonstrate how to construct the processor and achieve a minimum variance (optimal Bayesian) design. It is shown that both broadband pressure-field and modal function estimates can be extracted illustrating the feasibility of this approach. {copyright} {ital 1998 Acoustical Society of America.}

  6. The Design of Model-Based Training Programs

    NASA Technical Reports Server (NTRS)

    Polson, Peter; Sherry, Lance; Feary, Michael; Palmer, Everett; Alkin, Marty; McCrobie, Dan; Kelley, Jerry; Rosekind, Mark (Technical Monitor)

    1997-01-01

    This paper proposes a model-based training program for the skills necessary to operate advance avionics systems that incorporate advanced autopilots and fight management systems. The training model is based on a formalism, the operational procedure model, that represents the mission model, the rules, and the functions of a modem avionics system. This formalism has been defined such that it can be understood and shared by pilots, the avionics software, and design engineers. Each element of the software is defined in terms of its intent (What?), the rationale (Why?), and the resulting behavior (How?). The Advanced Computer Tutoring project at Carnegie Mellon University has developed a type of model-based, computer aided instructional technology called cognitive tutors. They summarize numerous studies showing that training times to a specified level of competence can be achieved in one third the time of conventional class room instruction. We are developing a similar model-based training program for the skills necessary to operation the avionics. The model underlying the instructional program and that simulates the effects of pilots entries and the behavior of the avionics is based on the operational procedure model. Pilots are given a series of vertical flightpath management problems. Entries that result in violations, such as failure to make a crossing restriction or violating the speed limits, result in error messages with instruction. At any time, the flightcrew can request suggestions on the appropriate set of actions. A similar and successful training program for basic skills for the FMS on the Boeing 737-300 was developed and evaluated. The results strongly support the claim that the training methodology can be adapted to the cockpit.

  7. A model-based multisensor data fusion knowledge management approach

    NASA Astrophysics Data System (ADS)

    Straub, Jeremy

    2014-06-01

    A variety of approaches exist for combining data from multiple sensors. The model-based approach combines data based on its support for or refutation of elements of the model which in turn can be used to evaluate an experimental thesis. This paper presents a collection of algorithms for mapping various types of sensor data onto a thesis-based model and evaluating the truth or falsity of the thesis, based on the model. The use of this approach for autonomously arriving at findings and for prioritizing data are considered. Techniques for updating the model (instead of arriving at a true/false assertion) are also discussed.

  8. Method for Real-Time Model Based Structural Anomaly Detection

    NASA Technical Reports Server (NTRS)

    Smith, Timothy A. (Inventor); Urnes, James M., Sr. (Inventor); Reichenbach, Eric Y. (Inventor)

    2015-01-01

    A system and methods for real-time model based vehicle structural anomaly detection are disclosed. A real-time measurement corresponding to a location on a vehicle structure during an operation of the vehicle is received, and the real-time measurement is compared to expected operation data for the location to provide a modeling error signal. A statistical significance of the modeling error signal to provide an error significance is calculated, and a persistence of the error significance is determined. A structural anomaly is indicated, if the persistence exceeds a persistence threshold value.

  9. Model-Based Information Extraction From Synthetic Aperture Radar Signals

    NASA Astrophysics Data System (ADS)

    Matzner, Shari A.

    2011-07-01

    Synthetic aperture radar (SAR) is a remote sensing technology for imaging areas of the earth's surface. SAR has been successfully used for monitoring characteristics of the natural environment such as land cover type and tree density. With the advent of higher resolution sensors, it is now theoretically possible to extract information about individual structures such as buildings from SAR imagery. This information could be used for disaster response and security-related intelligence. SAR has an advantage over other remote sensing technologies for these applications because SAR data can be collected during the night and in rainy or cloudy conditions. This research presents a model-based method for extracting information about a building -- its height and roof slope -- from a single SAR image. Other methods require multiple images or ancillary data from specialized sensors, making them less practical. The model-based method uses simulation to match a hypothesized building to an observed SAR image. The degree to which a simulation matches the observed data is measured by mutual information. The success of this method depends on the accuracy of the simulation and on the reliability of the mutual information similarity measure. Electromagnetic theory was applied to relate a building's physical characteristics to the features present in a SAR image. This understanding was used to quantify the precision of building information contained in SAR data, and to identify the inputs needed for accurate simulation. A new SAR simulation technique was developed to meet the accuracy and efficiency requirements of model-based information extraction. Mutual information, a concept from information theory, has become a standard for measuring the similarity between medical images. Its performance in the context of matching a simulation image to a SAR image was evaluated in this research, and it was found to perform well under certain conditions. The factors that affect its performance

  10. Temporal and contextual knowledge in model-based expert systems

    NASA Technical Reports Server (NTRS)

    Toth-Fejel, Tihamer; Heher, Dennis

    1987-01-01

    A basic paradigm that allows representation of physical systems with a focus on context and time is presented. Paragon provides the capability to quickly capture an expert's knowledge in a cognitively resonant manner. From that description, Paragon creates a simulation model in LISP, which when executed, verifies that the domain expert did not make any mistakes. The Achille's heel of rule-based systems has been the lack of a systematic methodology for testing, and Paragon's developers are certain that the model-based approach overcomes that problem. The reason this testing is now possible is that software, which is very difficult to test, has in essence been transformed into hardware.

  11. Model-based engineering for medical-device software.

    PubMed

    Ray, Arnab; Jetley, Raoul; Jones, Paul L; Zhang, Yi

    2010-01-01

    This paper demonstrates the benefits of adopting model-based design techniques for engineering medical device software. By using a patient-controlled analgesic (PCA) infusion pump as a candidate medical device, the authors show how using models to capture design information allows for i) fast and efficient construction of executable device prototypes ii) creation of a standard, reusable baseline software architecture for a particular device family, iii) formal verification of the design against safety requirements, and iv) creation of a safety framework that reduces verification costs for future versions of the device software. 1. PMID:21142522

  12. A parametric vocal fold model based on magnetic resonance imaging.

    PubMed

    Wu, Liang; Zhang, Zhaoyan

    2016-08-01

    This paper introduces a parametric three-dimensional body-cover vocal fold model based on magnetic resonance imaging (MRI) of the human larynx. Major geometric features that are observed in the MRI images but missing in current vocal fold models are discussed, and their influence on vocal fold vibration is evaluated using eigenmode analysis. Proper boundary conditions for the model are also discussed. Based on control parameters corresponding to anatomic landmarks that can be easily measured, this model can be adapted toward a subject-specific vocal fold model for voice production research and clinical applications. PMID:27586774

  13. A model-based executive for commanding robot teams

    NASA Technical Reports Server (NTRS)

    Barrett, Anthony

    2005-01-01

    The paper presents a way to robustly command a system of systems as a single entity. Instead of modeling each component system in isolation and then manually crafting interaction protocols, this approach starts with a model of the collective population as a single system. By compiling the model into separate elements for each component system and utilizing a teamwork model for coordination, it circumvents the complexities of manually crafting robust interaction protocols. The resulting systems are both globally responsive by virtue of a team oriented interaction model and locally responsive by virtue of a distributed approach to model-based fault detection, isolation, and recovery.

  14. Spring-Model-Based Wireless Localization in Cooperative User Environments

    NASA Astrophysics Data System (ADS)

    Ke, Wei; Wu, Lenan; Qi, Chenhao

    To overcome the shortcomings of conventional cellular positioning, a novel cooperative location algorithm that uses the available peer-to-peer communication between the mobile terminals (MTs) is proposed. The main idea behind the proposed approach is to incorporate the long- and short-range location information to improve the estimation of the MT's coordinates. Since short-range communications among MTs are characterized by high line-of-sight (LOS) probability, an improved spring-model-based cooperative location method can be exploited to provide low-cost improvement for cellular-based location in the non-line-of-sight (NLOS) environments.

  15. Hot blast stove process model and model-based controller

    SciTech Connect

    Muske, K.R.; Howse, J.W.; Hansen, G.A.; Cagliostro, D.J.; Chaubal, P.C.

    1998-12-31

    This paper describes the process model and model-based control techniques implemented on the hot blast stoves for the No. 7 Blast Furnace at the Inland Steel facility in East Chicago, Indiana. A detailed heat transfer model of the stoves is developed and verified using plant data. This model is used as part of a predictive control scheme to determine the minimum amount of fuel necessary to achieve the blast air requirements. The model is also used to predict maximum and minimum temperature constraint violations within the stove so that the controller can take corrective actions while still achieving the required stove performance.

  16. Evaluating model accuracy for model-based reasoning

    NASA Technical Reports Server (NTRS)

    Chien, Steve; Roden, Joseph

    1992-01-01

    Described here is an approach to automatically assessing the accuracy of various components of a model. In this approach, actual data from the operation of a target system is used to drive statistical measures to evaluate the prediction accuracy of various portions of the model. We describe how these statistical measures of model accuracy can be used in model-based reasoning for monitoring and design. We then describe the application of these techniques to the monitoring and design of the water recovery system of the Environmental Control and Life Support System (ECLSS) of Space Station Freedom.

  17. A Cyber-Attack Detection Model Based on Multivariate Analyses

    NASA Astrophysics Data System (ADS)

    Sakai, Yuto; Rinsaka, Koichiro; Dohi, Tadashi

    In the present paper, we propose a novel cyber-attack detection model based on two multivariate-analysis methods to the audit data observed on a host machine. The statistical techniques used here are the well-known Hayashi's quantification method IV and cluster analysis method. We quantify the observed qualitative audit event sequence via the quantification method IV, and collect similar audit event sequence in the same groups based on the cluster analysis. It is shown in simulation experiments that our model can improve the cyber-attack detection accuracy in some realistic cases where both normal and attack activities are intermingled.

  18. A Model-Based System For Force Structure Analysis

    NASA Astrophysics Data System (ADS)

    Levitt, Tod S.; Kirby, Robert L.; Muller, Hans E.

    1985-04-01

    Given a set of image-derived vehicle detections and/or recognized military vehicles, SIGINT cues and a priori analysis of terrain, the force structure analysis (FSA) problem is to utilize knowledge of tactical doctrine and spatial deployment information to infer the existence of military forces such as batteries, companies, battalions, regiments, divisions, etc. A model-based system for FSA has been developed. It performs symbolic reasoning about force structures represented as geometric models. The FSA system is a stand-alone module which has also been developed as part of a larger system, the Advanced Digital Radar Image Exploitation System (ADRIES) for automated SAR image exploitation. The models recursively encode the component military units of a force structure, their expected spatial deployment, search priorities for model components, prior match probabilities, and type hierarchies for uncertain recognition. Partial and uncertain matching of models against data is the basic tool for building up hypotheses of the existence of force structures. Hypothesis management includes the functions of matching models against data, predicting the existence and location of unobserved force components, localization of search areas and resolution of conflicts between competing hypotheses. A subjective Bayesian inference calculus is used to accrue certainty of force structure hypotheses and resolve conflicts. Reasoning from uncertain vehicle level data, the system has successfully inferred the correct locations and components of force structures up to the battalion level. Key words: Force structure analysis, SAR, model-based reasoning, hypothesis management, search, matching, conflict resolution, Bayesian inference, uncertainty.

  19. Ocean acoustic signal processing: A model-based approach

    SciTech Connect

    Candy, J.V. ); Sullivan, E.J. )

    1992-12-01

    A model-based approach is proposed to solve the ocean acoustic signal processing problem that is based on a state-space representation of the normal-mode propagation model. It is shown that this representation can be utilized to spatially propagate both modal (depth) and range functions given the basic parameters (wave numbers, etc.) developed from the solution of the associated boundary value problem. This model is then generalized to the stochastic case where an approximate Gauss--Markov model evolves. The Gauss--Markov representation, in principle, allows the inclusion of stochastic phenomena such as noise and modeling errors in a consistent manner. Based on this framework, investigations are made of model-based solutions to the signal enhancement, detection and related parameter estimation problems. In particular, a modal/pressure field processor is designed that allows {ital in} {ital situ} recursive estimation of the sound velocity profile. Finally, it is shown that the associated residual or so-called innovation sequence that ensues from the recursive nature of this formulation can be employed to monitor the model's fit to the data and also form the basis of a sequential detector.

  20. Evaluation of Model-Based Training for Vertical Guidance Logic

    NASA Technical Reports Server (NTRS)

    Feary, Michael; Palmer, Everett; Sherry, Lance; Polson, Peter; Alkin, Marty; McCrobie, Dan; Kelley, Jerry; Rosekind, Mark (Technical Monitor)

    1997-01-01

    This paper will summarize the results of a study which introduces a structured, model based approach to learning how the automated vertical guidance system works on a modern commercial air transport. The study proposes a framework to provide accurate and complete information in an attempt to eliminate confusion about 'what the system is doing'. This study will examine a structured methodology for organizing the ideas on which the system was designed, communicating this information through the training material, and displaying it in the airplane. Previous research on model-based, computer aided instructional technology has shown reductions in the amount of time to a specified level of competence. The lessons learned from the development of these technologies are well suited for use with the design methodology which was used to develop the vertical guidance logic for a large commercial air transport. The design methodology presents the model from which to derive the training material, and the content of information to be displayed to the operator. The study consists of a 2 X 2 factorial experiment which will compare a new method of training vertical guidance logic and a new type of display. The format of the material used to derive both the training and the display will be provided by the Operational Procedure Methodology. The training condition will compare current training material to the new structured format. The display condition will involve a change of the content of the information displayed into pieces that agree with the concepts with which the system was designed.

  1. Model-based diagnosis of a carbon dioxide removal assembly

    NASA Astrophysics Data System (ADS)

    Throop, David R.; Scarl, Ethan A.

    1992-03-01

    Model-based diagnosis (MBD) has been applied to a variety of mechanisms, but few of these have been in fluid flow domains. Important mechanism variables in these domains are continuous, and the mechanisms commonly contain complex recycle patterns. These properties violate some of the common assumptions for MBD. The CO2 removal assembly (CDRA) for the cabin atmosphere aboard NASA's Space Station Freedom is such a mechanism. Early work on diagnosing similar mechanisms showed that purely associative diagnostic systems could not adequately handle these mechanisms' frequent reconfigurations. This suggested a model-based approach and KATE was adapted to the domain. KATE is a constraint-based MBD shell. It has been successfully applied to liquid flow problems in handling liquid oxygen. However, that domain does not involve complex recycle streams, but the CDRA does. KATE had solved constraint sets by propagating parameter values through constraints; this method often fails on constraints sets which describe recycle systems. KATE was therefore extended to allow it to use external algebraic programs to solve its constraint sets. This paper describes the representational challenges involved in that extension, and describes adaptions which allowed KATE to work within the representational limitations imposed by those algebraic programs. It also presents preliminary results of the CDRA modeling.

  2. Model-Based Diagnostics for Propellant Loading Systems

    NASA Technical Reports Server (NTRS)

    Daigle, Matthew John; Foygel, Michael; Smelyanskiy, Vadim N.

    2011-01-01

    The loading of spacecraft propellants is a complex, risky operation. Therefore, diagnostic solutions are necessary to quickly identify when a fault occurs, so that recovery actions can be taken or an abort procedure can be initiated. Model-based diagnosis solutions, established using an in-depth analysis and understanding of the underlying physical processes, offer the advanced capability to quickly detect and isolate faults, identify their severity, and predict their effects on system performance. We develop a physics-based model of a cryogenic propellant loading system, which describes the complex dynamics of liquid hydrogen filling from a storage tank to an external vehicle tank, as well as the influence of different faults on this process. The model takes into account the main physical processes such as highly nonequilibrium condensation and evaporation of the hydrogen vapor, pressurization, and also the dynamics of liquid hydrogen and vapor flows inside the system in the presence of helium gas. Since the model incorporates multiple faults in the system, it provides a suitable framework for model-based diagnostics and prognostics algorithms. Using this model, we analyze the effects of faults on the system, derive symbolic fault signatures for the purposes of fault isolation, and perform fault identification using a particle filter approach. We demonstrate the detection, isolation, and identification of a number of faults using simulation-based experiments.

  3. MODEL-BASED CLUSTERING OF LARGE NETWORKS1

    PubMed Central

    Vu, Duy Q.; Hunter, David R.; Schweinberger, Michael

    2015-01-01

    We describe a network clustering framework, based on finite mixture models, that can be applied to discrete-valued networks with hundreds of thousands of nodes and billions of edge variables. Relative to other recent model-based clustering work for networks, we introduce a more flexible modeling framework, improve the variational-approximation estimation algorithm, discuss and implement standard error estimation via a parametric bootstrap approach, and apply these methods to much larger data sets than those seen elsewhere in the literature. The more flexible framework is achieved through introducing novel parameterizations of the model, giving varying degrees of parsimony, using exponential family models whose structure may be exploited in various theoretical and algorithmic ways. The algorithms are based on variational generalized EM algorithms, where the E-steps are augmented by a minorization-maximization (MM) idea. The bootstrapped standard error estimates are based on an efficient Monte Carlo network simulation idea. Last, we demonstrate the usefulness of the model-based clustering framework by applying it to a discrete-valued network with more than 131,000 nodes and 17 billion edge variables. PMID:26605002

  4. Application of model based control to robotic manipulators

    NASA Technical Reports Server (NTRS)

    Petrosky, Lyman J.; Oppenheim, Irving J.

    1988-01-01

    A robot that can duplicate humam motion capabilities in such activities as balancing, reaching, lifting, and moving has been built and tested. These capabilities are achieved through the use of real time Model-Based Control (MBC) techniques which have recently been demonstrated. MBC accounts for all manipulator inertial forces and provides stable manipulator motion control even at high speeds. To effectively demonstrate the unique capabilities of MBC, an experimental robotic manipulator was constructed, which stands upright, balancing on a two wheel base. The mathematical modeling of dynamics inherent in MBC permit the control system to perform functions that are impossible with conventional non-model based methods. These capabilities include: (1) Stable control at all speeds of operation; (2) Operations requiring dynamic stability such as balancing; (3) Detection and monitoring of applied forces without the use of load sensors; (4) Manipulator safing via detection of abnormal loads. The full potential of MBC has yet to be realized. The experiments performed for this research are only an indication of the potential applications. MBC has no inherent stability limitations and its range of applicability is limited only by the attainable sampling rate, modeling accuracy, and sensor resolution. Manipulators could be designed to operate at the highest speed mechanically attainable without being limited by control inadequacies. Manipulators capable of operating many times faster than current machines would certainly increase productivity for many tasks.

  5. A probabilistic graphical model based stochastic input model construction

    SciTech Connect

    Wan, Jiang; Zabaras, Nicholas

    2014-09-01

    Model reduction techniques have been widely used in modeling of high-dimensional stochastic input in uncertainty quantification tasks. However, the probabilistic modeling of random variables projected into reduced-order spaces presents a number of computational challenges. Due to the curse of dimensionality, the underlying dependence relationships between these random variables are difficult to capture. In this work, a probabilistic graphical model based approach is employed to learn the dependence by running a number of conditional independence tests using observation data. Thus a probabilistic model of the joint PDF is obtained and the PDF is factorized into a set of conditional distributions based on the dependence structure of the variables. The estimation of the joint PDF from data is then transformed to estimating conditional distributions under reduced dimensions. To improve the computational efficiency, a polynomial chaos expansion is further applied to represent the random field in terms of a set of standard random variables. This technique is combined with both linear and nonlinear model reduction methods. Numerical examples are presented to demonstrate the accuracy and efficiency of the probabilistic graphical model based stochastic input models. - Highlights: • Data-driven stochastic input models without the assumption of independence of the reduced random variables. • The problem is transformed to a Bayesian network structure learning problem. • Examples are given in flows in random media.

  6. Model-based Processing of Microcantilever Sensor Arrays

    SciTech Connect

    Tringe, J W; Clague, D S; Candy, J V; Sinensky, A K; Lee, C L; Rudd, R E; Burnham, A K

    2005-04-27

    We have developed a model-based processor (MBP) for a microcantilever-array sensor to detect target species in solution. We perform a proof-of-concept experiment, fit model parameters to the measured data and use them to develop a Gauss-Markov simulation. We then investigate two cases of interest, averaged deflection data and multi-channel data. For this evaluation we extract model parameters via a model-based estimation, perform a Gauss-Markov simulation, design the optimal MBP and apply it to measured experimental data. The performance of the MBP in the multi-channel case is evaluated by comparison to a ''smoother'' (averager) typically used for microcantilever signal analysis. It is shown that the MBP not only provides a significant gain ({approx} 80dB) in signal-to-noise ratio (SNR), but also consistently outperforms the smoother by 40-60 dB. Finally, we apply the processor to the smoothed experimental data and demonstrate its capability for chemical detection. The MBP performs quite well, apart from a correctable systematic bias error.

  7. Model-based approach to real-time target detection

    NASA Astrophysics Data System (ADS)

    Hackett, Jay K.; Gold, Ed V.; Long, Daniel T.; Cloud, Eugene L.; Duvoisin, Herbert A.

    1992-09-01

    Land mine detection and extraction from infra-red (IR) scenes using real-time parallel processing is of significant interest to ground based infantry. The mine detection algorithms consist of several sub-processes to progress from raw input IR imagery to feature based mine nominations. Image enhancement is first applied; this consists of noise and sensor artifact removal. Edge grouping is used to determine the boundary of the objects. The generalized Hough Transform tuned to the land mine signature acts as a model based matched nomination filter. Once the object is found, the model is used to guide the labeling of each pixel as background, object, or object boundary. Using these labels to identify object regions, feature primitives are extracted in a high speed parallel processor. A feature based screener then compares each object's feature primitives to acceptable values and rejects all objects that do not resemble mines. This operation greatly reduces the number of objects that must be passed from a real-time parallel processor to the classifier. We will discuss details of this model- based approach, including results from actual IR field test imagery.

  8. Towards model-based control of Parkinson's disease

    PubMed Central

    Schiff, Steven J.

    2010-01-01

    Modern model-based control theory has led to transformative improvements in our ability to track the nonlinear dynamics of systems that we observe, and to engineer control systems of unprecedented efficacy. In parallel with these developments, our ability to build computational models to embody our expanding knowledge of the biophysics of neurons and their networks is maturing at a rapid rate. In the treatment of human dynamical disease, our employment of deep brain stimulators for the treatment of Parkinson’s disease is gaining increasing acceptance. Thus, the confluence of these three developments—control theory, computational neuroscience and deep brain stimulation—offers a unique opportunity to create novel approaches to the treatment of this disease. This paper explores the relevant state of the art of science, medicine and engineering, and proposes a strategy for model-based control of Parkinson’s disease. We present a set of preliminary calculations employing basal ganglia computational models, structured within an unscented Kalman filter for tracking observations and prescribing control. Based upon these findings, we will offer suggestions for future research and development. PMID:20368246

  9. Model-based reconstructive elasticity imaging of deep venous thrombosis.

    PubMed

    Aglyamov, Salavat; Skovoroda, Andrei R; Rubin, Jonathan M; O'Donnell, Matthew; Emelianov, Stanislav Y

    2004-05-01

    Deep venous thrombosis (DVT) and its sequela, pulmonary embolism, is a significant clinical problem. Once detected, DVT treatment is based on the age of the clot. There are no good noninvasive methods, however, to determine clot age. Previously, we demonstrated that imaging internal mechanical strains can identify and possibly age thrombus in a deep vein. In this study the deformation geometry for DVT elasticity imaging and its effect on Young's modulus estimates is addressed. A model-based reconstruction method is presented to estimate elasticity in which the clot-containing vessel is modeled as a layered cylinder. Compared to an unconstrained approach in reconstructive elasticity imaging, the proposed model-based approach has several advantages: only one component of the strain tensor is used; the minimization procedure is very fast; the method is highly efficient because an analytic solution of the forward elastic problem is used; and the method is not very sensitive to the details of the external load pattern--a characteristic that is important for free-hand, external, surface-applied deformation. The approach was tested theoretically using a numerical model, and experimentally on both tissue-like phantoms and an animal model of DVT. Results suggest that elasticity reconstruction may prove to be a practical adjunct to triplex scanning to detect, diagnose, and stage DVT. PMID:15217230

  10. Qualitative-Modeling-Based Silicon Neurons and Their Networks

    PubMed Central

    Kohno, Takashi; Sekikawa, Munehisa; Li, Jing; Nanami, Takuya; Aihara, Kazuyuki

    2016-01-01

    The ionic conductance models of neuronal cells can finely reproduce a wide variety of complex neuronal activities. However, the complexity of these models has prompted the development of qualitative neuron models. They are described by differential equations with a reduced number of variables and their low-dimensional polynomials, which retain the core mathematical structures. Such simple models form the foundation of a bottom-up approach in computational and theoretical neuroscience. We proposed a qualitative-modeling-based approach for designing silicon neuron circuits, in which the mathematical structures in the polynomial-based qualitative models are reproduced by differential equations with silicon-native expressions. This approach can realize low-power-consuming circuits that can be configured to realize various classes of neuronal cells. In this article, our qualitative-modeling-based silicon neuron circuits for analog and digital implementations are quickly reviewed. One of our CMOS analog silicon neuron circuits can realize a variety of neuronal activities with a power consumption less than 72 nW. The square-wave bursting mode of this circuit is explained. Another circuit can realize Class I and II neuronal activities with about 3 nW. Our digital silicon neuron circuit can also realize these classes. An auto-associative memory realized on an all-to-all connected network of these silicon neurons is also reviewed, in which the neuron class plays important roles in its performance. PMID:27378842

  11. Model-based patterns in prostate cancer mortality worldwide

    PubMed Central

    Fontes, F; Severo, M; Castro, C; Lourenço, S; Gomes, S; Botelho, F; La Vecchia, C; Lunet, N

    2013-01-01

    Background: Prostate cancer mortality has been decreasing in several high income countries and previous studies analysed the trends mostly according to geographical criteria. We aimed to identify patterns in the time trends of prostate cancer mortality across countries using a model-based approach. Methods: Model-based clustering was used to identify patterns of variation in prostate cancer mortality (1980–2010) across 37 European, five non-European high-income countries and four leading emerging economies. We characterised the patterns observed regarding the geographical distribution and gross national income of the countries, as well as the trends observed in mortality/incidence ratios. Results: We identified three clusters of countries with similar variation in prostate cancer mortality: pattern 1 (‘no mortality decline'), characterised by a continued increase throughout the whole period; patterns 2 (‘later mortality decline') and 3 (‘earlier mortality decline') depict mortality declines, starting in the late and early 1990s, respectively. These clusters are also homogeneous regarding the variation in the prostate cancer mortality/incidence ratios, while are heterogeneous with reference to the geographical region of the countries and distribution of the gross national income. Conclusion: We provide a general model for the description and interpretation of the trends in prostate cancer mortality worldwide, based on three main patterns. PMID:23660943

  12. Model-based Processing of Micro-cantilever Sensor Arrays

    SciTech Connect

    Tringe, J W; Clague, D S; Candy, J V; Lee, C L; Rudd, R E; Burnham, A K

    2004-11-17

    We develop a model-based processor (MBP) for a micro-cantilever array sensor to detect target species in solution. After discussing the generalized framework for this problem, we develop the specific model used in this study. We perform a proof-of-concept experiment, fit the model parameters to the measured data and use them to develop a Gauss-Markov simulation. We then investigate two cases of interest: (1) averaged deflection data, and (2) multi-channel data. In both cases the evaluation proceeds by first performing a model-based parameter estimation to extract the model parameters, next performing a Gauss-Markov simulation, designing the optimal MBP and finally applying it to measured experimental data. The simulation is used to evaluate the performance of the MBP in the multi-channel case and compare it to a ''smoother'' (''averager'') typically used in this application. It was shown that the MBP not only provides a significant gain ({approx} 80dB) in signal-to-noise ratio (SNR), but also consistently outperforms the smoother by 40-60 dB. Finally, we apply the processor to the smoothed experimental data and demonstrate its capability for chemical detection. The MBP performs quite well, though it includes a correctable systematic bias error. The project's primary accomplishment was the successful application of model-based processing to signals from micro-cantilever arrays: 40-60 dB improvement vs. the smoother algorithm was demonstrated. This result was achieved through the development of appropriate mathematical descriptions for the chemical and mechanical phenomena, and incorporation of these descriptions directly into the model-based signal processor. A significant challenge was the development of the framework which would maximize the usefulness of the signal processing algorithms while ensuring the accuracy of the mathematical description of the chemical-mechanical signal. Experimentally, the difficulty was to identify and characterize the non

  13. Model-Based Signal Processing: Correlation Detection With Synthetic Seismograms

    SciTech Connect

    Rodgers, A; Harris, D; Pasyanos, M; Blair, S; Matt, R

    2006-08-30

    Recent applications of correlation methods to seismological problems illustrate the power of coherent signal processing applied to seismic waveforms. Examples of these applications include detection of low amplitude signals buried in ambient noise and cross-correlation of sets of waveforms to form event clusters and accurately measure delay times for event relocation and/or earth structure. These methods rely on the exploitation of the similarity of individual waveforms and have been successfully applied to large sets of empirical observations. However, in cases with little or no empirical event data, such as aseismic regions or exotic event types, correlation methods with observed seismograms will not be possible due to the lack of previously observed similar waveforms. This study uses model-based signals computed for three-dimensional (3D) Earth models to form the basis for correlation detection. Synthetic seismograms are computed for fully 3D models estimated from the Markov Chain Monte-Carlo (MCMC) method. MCMC uses stochastic sampling to fit multiple seismological data sets. Rather than estimate a single ''optimal'' model, MCMC results in a suite of models that sample the model space and incorporates uncertainty through variability of the models. The variability reflects our ignorance of Earth structure, due to limited resolution, data and modeling errors, and produces variability in the seismic waveform response. Model-based signals are combined using a subspace method where the synthetic signals are decomposed into an orthogonal basis by singular-value decomposition (SVD) and the observed waveforms are represented with a linear combination of a sub-set of eigenvectors (signals) associated with the most significant eigenvalues. We have demonstrated the method by modeling long-period (80-10 seconds) regional seismograms for a moderate (M{approx}5) earthquake near the China-North Korea border. Synthetic seismograms are computed with the Spectral Element Method

  14. Reducing Centroid Error Through Model-Based Noise Reduction

    NASA Technical Reports Server (NTRS)

    Lee, Shinhak

    2006-01-01

    A method of processing the digitized output of a charge-coupled device (CCD) image detector has been devised to enable reduction of the error in computed centroid of the image of a point source of light. The method involves model-based estimation of, and correction for, the contributions of bias and noise to the image data. The method could be used to advantage in any of a variety of applications in which there are requirements for measuring precise locations of, and/or precisely aiming optical instruments toward, point light sources. In the present method, prior to normal operations of the CCD, one measures the point-spread function (PSF) of the telescope or other optical system used to project images on the CCD. The PSF is used to construct a database of spot models representing the nominal CCD pixel outputs for a point light source projected onto the CCD at various positions incremented by small fractions of a pixel.

  15. Model-based condition monitoring for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Kim, Taesic; Wang, Yebin; Fang, Huazhen; Sahinoglu, Zafer; Wada, Toshihiro; Hara, Satoshi; Qiao, Wei

    2015-11-01

    Condition monitoring for batteries involves tracking changes in physical parameters and operational states such as state of health (SOH) and state of charge (SOC), and is fundamentally important for building high-performance and safety-critical battery systems. A model-based condition monitoring strategy is developed in this paper for Lithium-ion batteries on the basis of an electrical circuit model incorporating hysteresis effect. It systematically integrates 1) a fast upper-triangular and diagonal recursive least squares algorithm for parameter identification of the battery model, 2) a smooth variable structure filter for the SOC estimation, and 3) a recursive total least squares algorithm for estimating the maximum capacity, which indicates the SOH. The proposed solution enjoys advantages including high accuracy, low computational cost, and simple implementation, and therefore is suitable for deployment and use in real-time embedded battery management systems (BMSs). Simulations and experiments validate effectiveness of the proposed strategy.

  16. Performability modeling based on real data: A casestudy

    NASA Technical Reports Server (NTRS)

    Hsueh, M. C.; Iyer, R. K.; Trivedi, K. S.

    1987-01-01

    Described is a measurement-based performability model based on error and resource usage data collected on a multiprocessor system. A method for identifying the model structure is introduced and the resulting model is validated against real data. Model development from the collection of raw data to the estimation of the expected reward is described. Both normal and error behavior of the system are characterized. The measured data show that the holding times in key operational and error states are not simple exponentials and that a semi-Markov process is necessary to model the system behavior. A reward function, based on the service rate and the error rate in each state, is then defined in order to estimate the performability of the system and to depict the cost of different types of errors.

  17. Numerical analysis of modeling based on improved Elman neural network.

    PubMed

    Jie, Shao; Li, Wang; WeiSong, Zhao; YaQin, Zhong; Malekian, Reza

    2014-01-01

    A modeling based on the improved Elman neural network (IENN) is proposed to analyze the nonlinear circuits with the memory effect. The hidden layer neurons are activated by a group of Chebyshev orthogonal basis functions instead of sigmoid functions in this model. The error curves of the sum of squared error (SSE) varying with the number of hidden neurons and the iteration step are studied to determine the number of the hidden layer neurons. Simulation results of the half-bridge class-D power amplifier (CDPA) with two-tone signal and broadband signals as input have shown that the proposed behavioral modeling can reconstruct the system of CDPAs accurately and depict the memory effect of CDPAs well. Compared with Volterra-Laguerre (VL) model, Chebyshev neural network (CNN) model, and basic Elman neural network (BENN) model, the proposed model has better performance. PMID:25054172

  18. The algorithmic anatomy of model-based evaluation

    PubMed Central

    Daw, Nathaniel D.; Dayan, Peter

    2014-01-01

    Despite many debates in the first half of the twentieth century, it is now largely a truism that humans and other animals build models of their environments and use them for prediction and control. However, model-based (MB) reasoning presents severe computational challenges. Alternative, computationally simpler, model-free (MF) schemes have been suggested in the reinforcement learning literature, and have afforded influential accounts of behavioural and neural data. Here, we study the realization of MB calculations, and the ways that this might be woven together with MF values and evaluation methods. There are as yet mostly only hints in the literature as to the resulting tapestry, so we offer more preview than review. PMID:25267820

  19. Qualitative model-based diagnostics for rocket systems

    NASA Technical Reports Server (NTRS)

    Maul, William; Meyer, Claudia; Jankovsky, Amy; Fulton, Christopher

    1993-01-01

    A diagnostic software package is currently being developed at NASA LeRC that utilizes qualitative model-based reasoning techniques. These techniques can provide diagnostic information about the operational condition of the modeled rocket engine system or subsystem. The diagnostic package combines a qualitative model solver with a constraint suspension algorithm. The constraint suspension algorithm directs the solver's operation to provide valuable fault isolation information about the modeled system. A qualitative model of the Space Shuttle Main Engine's oxidizer supply components was generated. A diagnostic application based on this qualitative model was constructed to process four test cases: three numerical simulations and one actual test firing. The diagnostic tool's fault isolation output compared favorably with the input fault condition.

  20. CDMBE: A Case Description Model Based on Evidence.

    PubMed

    Zhu, Jianlin; Yang, Xiaoping; Zhou, Jing

    2015-01-01

    By combining the advantages of argument map and Bayesian network, a case description model based on evidence (CDMBE), which is suitable to continental law system, is proposed to describe the criminal cases. The logic of the model adopts the credibility logical reason and gets evidence-based reasoning quantitatively based on evidences. In order to consist with practical inference rules, five types of relationship and a set of rules are defined to calculate the credibility of assumptions based on the credibility and supportability of the related evidences. Experiments show that the model can get users' ideas into a figure and the results calculated from CDMBE are in line with those from Bayesian model. PMID:26421006

  1. Automated Decomposition of Model-based Learning Problems

    NASA Technical Reports Server (NTRS)

    Williams, Brian C.; Millar, Bill

    1996-01-01

    A new generation of sensor rich, massively distributed autonomous systems is being developed that has the potential for unprecedented performance, such as smart buildings, reconfigurable factories, adaptive traffic systems and remote earth ecosystem monitoring. To achieve high performance these massive systems will need to accurately model themselves and their environment from sensor information. Accomplishing this on a grand scale requires automating the art of large-scale modeling. This paper presents a formalization of [\\em decompositional model-based learning (DML)], a method developed by observing a modeler's expertise at decomposing large scale model estimation tasks. The method exploits a striking analogy between learning and consistency-based diagnosis. Moriarty, an implementation of DML, has been applied to thermal modeling of a smart building, demonstrating a significant improvement in learning rate.

  2. Model-based approach for elevator performance estimation

    NASA Astrophysics Data System (ADS)

    Esteban, E.; Salgado, O.; Iturrospe, A.; Isasa, I.

    2016-02-01

    In this paper, a dynamic model for an elevator installation is presented in the state space domain. The model comprises both the mechanical and the electrical subsystems, including the electrical machine and a closed-loop field oriented control. The proposed model is employed for monitoring the condition of the elevator installation. The adopted model-based approach for monitoring employs the Kalman filter as an observer. A Kalman observer estimates the elevator car acceleration, which determines the elevator ride quality, based solely on the machine control signature and the encoder signal. Finally, five elevator key performance indicators are calculated based on the estimated car acceleration. The proposed procedure is experimentally evaluated, by comparing the key performance indicators calculated based on the estimated car acceleration and the values obtained from actual acceleration measurements in a test bench. Finally, the proposed procedure is compared with the sliding mode observer.

  3. Enhancements to the KATE model-based reasoning system

    NASA Technical Reports Server (NTRS)

    Thomas, Stan J.

    1994-01-01

    KATE (Knowledge-based Autonomous Test Engineer) is a model-based software system developed in the Artificial Intelligence Laboratory at the Kennedy Space Center for monitoring, fault detection, and control of launch vehicles and ground support systems. This report describes two software efforts which enhance the functionality and usability of KATE. The first addition, a flow solver, adds to KATE a tool for modeling the flow of liquid in a pipe system. The second addition adds support for editing KATE knowledge base files to the Emacs editor. The body of this report discusses design and implementation issues having to do with these two tools. It will be useful to anyone maintaining or extending either the flow solver or the editor enhancements.

  4. CDMBE: A Case Description Model Based on Evidence

    PubMed Central

    Zhu, Jianlin; Yang, Xiaoping; Zhou, Jing

    2015-01-01

    By combining the advantages of argument map and Bayesian network, a case description model based on evidence (CDMBE), which is suitable to continental law system, is proposed to describe the criminal cases. The logic of the model adopts the credibility logical reason and gets evidence-based reasoning quantitatively based on evidences. In order to consist with practical inference rules, five types of relationship and a set of rules are defined to calculate the credibility of assumptions based on the credibility and supportability of the related evidences. Experiments show that the model can get users' ideas into a figure and the results calculated from CDMBE are in line with those from Bayesian model. PMID:26421006

  5. Model-Based Systems Engineering Approach to Managing Mass Margin

    NASA Technical Reports Server (NTRS)

    Chung, Seung H.; Bayer, Todd J.; Cole, Bjorn; Cooke, Brian; Dekens, Frank; Delp, Christopher; Lam, Doris

    2012-01-01

    When designing a flight system from concept through implementation, one of the fundamental systems engineering tasks ismanaging the mass margin and a mass equipment list (MEL) of the flight system. While generating a MEL and computing a mass margin is conceptually a trivial task, maintaining consistent and correct MELs and mass margins can be challenging due to the current practices of maintaining duplicate information in various forms, such as diagrams and tables, and in various media, such as files and emails. We have overcome this challenge through a model-based systems engineering (MBSE) approach within which we allow only a single-source-of-truth. In this paper we describe the modeling patternsused to capture the single-source-of-truth and the views that have been developed for the Europa Habitability Mission (EHM) project, a mission concept study, at the Jet Propulsion Laboratory (JPL).

  6. A social discounting model based on Tsallis’ statistics

    NASA Astrophysics Data System (ADS)

    Takahashi, Taiki

    2010-09-01

    Social decision making (e.g. social discounting and social preferences) has been attracting attention in economics, econophysics, social physics, behavioral psychology, and neuroeconomics. This paper proposes a novel social discounting model based on the deformed algebra developed in the Tsallis’ non-extensive thermostatistics. Furthermore, it is suggested that this model can be utilized to quantify the degree of consistency in social discounting in humans and analyze the relationships between behavioral tendencies in social discounting and other-regarding economic decision making under game-theoretic conditions. Future directions in the application of the model to studies in econophysics, neuroeconomics, and social physics, as well as real-world problems such as the supply of live organ donations, are discussed.

  7. Prediction model based on decision tree analysis for laccase mediators.

    PubMed

    Medina, Fabiola; Aguila, Sergio; Baratto, Maria Camilla; Martorana, Andrea; Basosi, Riccardo; Alderete, Joel B; Vazquez-Duhalt, Rafael

    2013-01-10

    A Structure Activity Relationship (SAR) study for laccase mediator systems was performed in order to correctly classify different natural phenolic mediators. Decision tree (DT) classification models with a set of five quantum-chemical calculated molecular descriptors were used. These descriptors included redox potential (ɛ°), ionization energy (E(i)), pK(a), enthalpy of formation of radical (Δ(f)H), and OH bond dissociation energy (D(O-H)). The rationale for selecting these descriptors is derived from the laccase-mediator mechanism. To validate the DT predictions, the kinetic constants of different compounds as laccase substrates, their ability for pesticide transformation as laccase-mediators, and radical stability were experimentally determined using Coriolopsis gallica laccase and the pesticide dichlorophen. The prediction capability of the DT model based on three proposed descriptors showed a complete agreement with the obtained experimental results. PMID:23199741

  8. Active Shape Model-Based Gait Recognition Using Infrared Images

    NASA Astrophysics Data System (ADS)

    Kim, Daehee; Lee, Seungwon; Paik, Joonki

    We present a gait recognition system using infra-red (IR) images. Since an IR camera is not affected by the intensity of illumination, it is able to provide constant recognition performance regardless of the amount of illumination. Model-based object tracking algorithms enable robust tracking with partial occlusions or dynamic illumination. However, this algorithm often fails in tracking objects if strong edge exists near the object. Replacement of the input image by an IR image guarantees robust object region extraction because background edges do not affect the IR image. In conclusion, the proposed gait recognition algorithm improves accuracy in object extraction by using IR images and the improvements finally increase the recognition rate of gaits.

  9. On the Performance of Stochastic Model-Based Image Segmentation

    NASA Astrophysics Data System (ADS)

    Lei, Tianhu; Sewchand, Wilfred

    1989-11-01

    A new stochastic model-based image segmentation technique for X-ray CT image has been developed and has been extended to the more general nondiffraction CT images which include MRI, SPELT, and certain type of ultrasound images [1,2]. The nondiffraction CT image is modeled by a Finite Normal Mixture. The technique utilizes the information theoretic criterion to detect the number of the region images, uses the Expectation-Maximization algorithm to estimate the parameters of the image, and uses the Bayesian classifier to segment the observed image. How does this technique over/under-estimate the number of the region images? What is the probability of errors in the segmentation of this technique? This paper addresses these two problems and is a continuation of [1,2].

  10. Model-Based Systems Engineering Pilot Program at NASA Langley

    NASA Technical Reports Server (NTRS)

    Vipavetz, Kevin G.; Murphy, Douglas G.; Infeld, Samatha I.

    2012-01-01

    NASA Langley Research Center conducted a pilot program to evaluate the benefits of using a Model-Based Systems Engineering (MBSE) approach during the early phase of the Materials International Space Station Experiment-X (MISSE-X) project. The goal of the pilot was to leverage MBSE tools and methods, including the Systems Modeling Language (SysML), to understand the net gain of utilizing this approach on a moderate size flight project. The System Requirements Review (SRR) success criteria were used to guide the work products desired from the pilot. This paper discusses the pilot project implementation, provides SysML model examples, identifies lessons learned, and describes plans for further use on MBSE on MISSE-X.

  11. Model-based needle control in prostate percutaneous procedures.

    PubMed

    Maghsoudi, Arash; Jahed, Mehran

    2013-01-01

    In percutaneous applications, needle insertion into soft tissue is considered as a challenging procedure, and hence, it has been the subject of many recent studies. This study considers a model-based dynamics equation to evaluate the needle movement through prostate soft tissue. The proposed model estimates the applied force to the needle using the tissue deformation data and finite element model of the tissue. To address the role of mechanical properties of the soft tissue, an inverse dynamics control method based on sliding mode approach is used to demonstrate system performance in the presence of uncertainties. Furthermore, to deal with inaccurate estimation of mechanical parameters of the soft tissue, an adaptive controller is developed. Moreover, through a sensitivity analysis, it is shown that the uncertainty in the tissue mechanical parameters affects the system performance. Our results indicate that the adaptive controller approach performs slightly better than inverse dynamics method at the expense of fine-tuning the additional gain parameter. PMID:23516956

  12. An Evolutionary Model Based on Bit-String with Intelligence

    NASA Astrophysics Data System (ADS)

    He, Mingfeng; Pan, Qiuhui; Yu, Binglin

    An evolutionary model based on bit-strings with intelligence is set up in this paper. In this model, gene is divided into two parts which relative to health and intelligence. The accumulated intelligence influences the survival process by the effect of food and space restrictions. We modify the Verhulst factor to study this effect. Both asexual and sexual model are discussed in this paper. The results show that after many time steps, stability is reached and the population self-organizes, just like the standard Penna model. The intelligence made the equilibrium to be reached larger both in asexual model and sexual model. Compared with asexual model the population size fluctuates more strongly in the sexual model.

  13. Model-Based Engineering and Manufacturing CAD/CAM Benchmark.

    SciTech Connect

    Domm, T.C.; Underwood, R.S.

    1999-10-13

    The Benchmark Project was created from a desire to identify best practices and improve the overall efficiency and performance of the Y-12 Plant's systems and personnel supporting the manufacturing mission. The mission of the benchmark team was to search out industry leaders in manufacturing and evaluate their engineering practices and processes to determine direction and focus for Y-12 modernization efforts. The companies visited included several large established companies and a new, small, high-tech machining firm. As a result of this effort, changes are recommended that will enable Y-12 to become a more modern, responsive, cost-effective manufacturing facility capable of supporting the needs of the Nuclear Weapons Complex (NWC) into the 21st century. The benchmark team identified key areas of interest, both focused and general. The focus areas included Human Resources, Information Management, Manufacturing Software Tools, and Standards/Policies and Practices. Areas of general interest included Infrastructure, Computer Platforms and Networking, and Organizational Structure. The results of this benchmark showed that all companies are moving in the direction of model-based engineering and manufacturing. There was evidence that many companies are trying to grasp how to manage current and legacy data. In terms of engineering design software tools, the companies contacted were somewhere between 3-D solid modeling and surfaced wire-frame models. The manufacturing computer tools were varied, with most companies using more than one software product to generate machining data and none currently performing model-based manufacturing (MBM) from a common model. The majority of companies were closer to identifying or using a single computer-aided design (CAD) system than a single computer-aided manufacturing (CAM) system. The Internet was a technology that all companies were looking to either transport information more easily throughout the corporation or as a conduit for

  14. Neural mass model-based tracking of anesthetic brain states.

    PubMed

    Kuhlmann, Levin; Freestone, Dean R; Manton, Jonathan H; Heyse, Bjorn; Vereecke, Hugo E M; Lipping, Tarmo; Struys, Michel M R F; Liley, David T J

    2016-06-01

    Neural mass model-based tracking of brain states from electroencephalographic signals holds the promise of simultaneously tracking brain states while inferring underlying physiological changes in various neuroscientific and clinical applications. Here, neural mass model-based tracking of brain states using the unscented Kalman filter applied to estimate parameters of the Jansen-Rit cortical population model is evaluated through the application of propofol-based anesthetic state monitoring. In particular, 15 subjects underwent propofol anesthesia induction from awake to anesthetised while behavioral responsiveness was monitored and frontal electroencephalographic signals were recorded. The unscented Kalman filter Jansen-Rit model approach applied to frontal electroencephalography achieved reasonable testing performance for classification of the anesthetic brain state (sensitivity: 0.51; chance sensitivity: 0.17; nearest neighbor sensitivity 0.75) when compared to approaches based on linear (autoregressive moving average) modeling (sensitivity 0.58; nearest neighbor sensitivity: 0.91) and a high performing standard depth of anesthesia monitoring measure, Higuchi Fractal Dimension (sensitivity: 0.50; nearest neighbor sensitivity: 0.88). Moreover, it was found that the unscented Kalman filter based parameter estimates of the inhibitory postsynaptic potential amplitude varied in the physiologically expected direction with increases in propofol concentration, while the estimates of the inhibitory postsynaptic potential rate constant did not. These results combined with analysis of monotonicity of parameter estimates, error analysis of parameter estimates, and observability analysis of the Jansen-Rit model, along with considerations of extensions of the Jansen-Rit model, suggests that the Jansen-Rit model combined with unscented Kalman filtering provides a valuable reference point for future real-time brain state tracking studies. This is especially true for studies of

  15. New high-order, semi-implicit Hybridized Discontinuous Galerkin - Spectral Element Method (HDG-SEM) for simulation of complex wave propagation involving coupling between seismic, hydro-acoustic and infrasonic waves: numerical analysis and case studies.

    NASA Astrophysics Data System (ADS)

    Terrana, S.; Vilotte, J. P.; Guillot, L.

    2015-12-01

    New seismological monitoring networks combine broadband seismic receivers, hydrophones and micro-barometers antenna, providing complementary observation of source-radiated waves. Exploiting these observations requires accurate and multi-media - elastic, hydro-acoustic, infrasound - wave simulation methods, in order to improve our physical understanding of energy exchanges at material interfaces.We present here a new development of a high-order Hybridized Discontinuous Galerkin (HDG) method, for the simulation of coupled seismic and acoustic wave propagation, within a unified framework ([1],[2]) allowing for continuous and discontinuous Spectral Element Methods (SEM) to be used in the same simulation, with conforming and non-conforming meshes. The HDG-SEM approximation leads to differential - algebraic equations, which can be solved implicitly using energy-preserving time-schemes.The proposed HDG-SEM is computationally attractive, when compared with classical Discontinuous Galerkin methods, involving only the approximation of the single-valued traces of the velocity field along the element interfaces as globally coupled unknowns. The formulation is based on a variational approximation of the physical fluxes, which are shown to be the explicit solution of an exact Riemann problem at each element boundaries. This leads to a highly parallel and efficient unstructured and high-order accurate method, which can be space-and-time adaptive.A numerical study of the accuracy and convergence of the HDG-SEM is performed through a number of case studies involving elastic-acoustic (infrasound) coupling with geometries of increasing complexity. Finally, the performance of the method is illustrated through realistic case studies involving ground wave propagation associated to topography effects.In conclusion, we outline some on-going extensions of the method.References:[1] Cockburn, B., Gopalakrishnan, J., Lazarov, R., Unified hybridization of discontinuous Galerkin, mixed and

  16. Model-based cartilage thickness measurement in the submillimeter range

    SciTech Connect

    Streekstra, G. J.; Strackee, S. D.; Maas, M.; Wee, R. ter; Venema, H. W.

    2007-09-15

    Current methods of image-based thickness measurement in thin sheet structures utilize second derivative zero crossings to locate the layer boundaries. It is generally acknowledged that the nonzero width of the point spread function (PSF) limits the accuracy of this measurement procedure. We propose a model-based method that strongly reduces PSF-induced bias by incorporating the PSF into the thickness estimation method. We estimated the bias in thickness measurements in simulated thin sheet images as obtained from second derivative zero crossings. To gain insight into the range of sheet thickness where our method is expected to yield improved results, sheet thickness was varied between 0.15 and 1.2 mm with an assumed PSF as present in the high-resolution modes of current computed tomography (CT) scanners [full width at half maximum (FWHM) 0.5-0.8 mm]. Our model-based method was evaluated in practice by measuring layer thickness from CT images of a phantom mimicking two parallel cartilage layers in an arthrography procedure. CT arthrography images of cadaver wrists were also evaluated, and thickness estimates were compared to those obtained from high-resolution anatomical sections that served as a reference. The thickness estimates from the simulated images reveal that the method based on second derivative zero crossings shows considerable bias for layers in the submillimeter range. This bias is negligible for sheet thickness larger than 1 mm, where the size of the sheet is more than twice the FWHM of the PSF but can be as large as 0.2 mm for a 0.5 mm sheet. The results of the phantom experiments show that the bias is effectively reduced by our method. The deviations from the true thickness, due to random fluctuations induced by quantum noise in the CT images, are of the order of 3% for a standard wrist imaging protocol. In the wrist the submillimeter thickness estimates from the CT arthrography images correspond within 10% to those estimated from the anatomical

  17. Biased Randomized Algorithm for Fast Model-Based Diagnosis

    NASA Technical Reports Server (NTRS)

    Williams, Colin; Vartan, Farrokh

    2005-01-01

    A biased randomized algorithm has been developed to enable the rapid computational solution of a propositional- satisfiability (SAT) problem equivalent to a diagnosis problem. The closest competing methods of automated diagnosis are described in the preceding article "Fast Algorithms for Model-Based Diagnosis" and "Two Methods of Efficient Solution of the Hitting-Set Problem" (NPO-30584), which appears elsewhere in this issue. It is necessary to recapitulate some of the information from the cited articles as a prerequisite to a description of the present method. As used here, "diagnosis" signifies, more precisely, a type of model-based diagnosis in which one explores any logical inconsistencies between the observed and expected behaviors of an engineering system. The function of each component and the interconnections among all the components of the engineering system are represented as a logical system. Hence, the expected behavior of the engineering system is represented as a set of logical consequences. Faulty components lead to inconsistency between the observed and expected behaviors of the system, represented by logical inconsistencies. Diagnosis - the task of finding the faulty components - reduces to finding the components, the abnormalities of which could explain all the logical inconsistencies. One seeks a minimal set of faulty components (denoted a minimal diagnosis), because the trivial solution, in which all components are deemed to be faulty, always explains all inconsistencies. In the methods of the cited articles, the minimal-diagnosis problem is treated as equivalent to a minimal-hitting-set problem, which is translated from a combinatorial to a computational problem by mapping it onto the Boolean-satisfiability and integer-programming problems. The integer-programming approach taken in one of the prior methods is complete (in the sense that it is guaranteed to find a solution if one exists) and slow and yields a lower bound on the size of the

  18. Development of land surface reflectance models based on multiscale simulation

    NASA Astrophysics Data System (ADS)

    Goodenough, Adam A.; Brown, Scott D.

    2015-05-01

    Modeling and simulation of Earth imaging sensors with large spatial coverage necessitates an understanding of how photons interact with individual land surface processes at an aggregate level. For example, the leaf angle distribution of a deciduous forest canopy has a significant impact on the path of a single photon as it is scattered among the leaves and, consequently, a significant impact on the observed bidirectional reflectance distribution function (BRDF) of the canopy as a whole. In particular, simulation of imagery of heterogeneous scenes for many multispectral/hyperspectral applications requires detailed modeling of regions of the spectrum where many orders of scattering are required due to both high reflectance and transmittance. Radiative transfer modeling based on ray tracing, hybrid Monte Carlo techniques and detailed geometric and optical models of land cover means that it is possible to build effective, aggregate optical models with parameters such as species, spatial distribution, and underlying terrain variation. This paper examines the capability of the Digital Image and Remote Sensing Image Generation (DIRSIG) model to generate BRDF data representing land surfaces at large scale from modeling at a much smaller scale. We describe robust methods for generating optical property models effectively in DIRSIG and present new tools for facilitating the process. The methods and results for forest canopies are described relative to the RAdiation transfer Model Intercomparison (RAMI) benchmark scenes, which also forms the basis for an evaluation of the approach. Additional applications and examples are presented, representing different types of land cover.

  19. Advanced electron crystallography through model-based imaging.

    PubMed

    Van Aert, Sandra; De Backer, Annick; Martinez, Gerardo T; den Dekker, Arnold J; Van Dyck, Dirk; Bals, Sara; Van Tendeloo, Gustaaf

    2016-01-01

    The increasing need for precise determination of the atomic arrangement of non-periodic structures in materials design and the control of nanostructures explains the growing interest in quantitative transmission electron microscopy. The aim is to extract precise and accurate numbers for unknown structure parameters including atomic positions, chemical concentrations and atomic numbers. For this purpose, statistical parameter estimation theory has been shown to provide reliable results. In this theory, observations are considered purely as data planes, from which structure parameters have to be determined using a parametric model describing the images. As such, the positions of atom columns can be measured with a precision of the order of a few picometres, even though the resolution of the electron microscope is still one or two orders of magnitude larger. Moreover, small differences in average atomic number, which cannot be distinguished visually, can be quantified using high-angle annular dark-field scanning transmission electron microscopy images. In addition, this theory allows one to measure compositional changes at interfaces, to count atoms with single-atom sensitivity, and to reconstruct atomic structures in three dimensions. This feature article brings the reader up to date, summarizing the underlying theory and highlighting some of the recent applications of quantitative model-based transmisson electron microscopy. PMID:26870383

  20. Automatic sensor placement for model-based robot vision.

    PubMed

    Chen, S Y; Li, Y F

    2004-02-01

    This paper presents a method for automatic sensor placement for model-based robot vision. In such a vision system, the sensor often needs to be moved from one pose to another around the object to observe all features of interest. This allows multiple three-dimensional (3-D) images to be taken from different vantage viewpoints. The task involves determination of the optimal sensor placements and a shortest path through these viewpoints. During the sensor planning, object features are resampled as individual points attached with surface normals. The optimal sensor placement graph is achieved by a genetic algorithm in which a min-max criterion is used for the evaluation. A shortest path is determined by Christofides algorithm. A Viewpoint Planner is developed to generate the sensor placement plan. It includes many functions, such as 3-D animation of the object geometry, sensor specification, initialization of the viewpoint number and their distribution, viewpoint evolution, shortest path computation, scene simulation of a specific viewpoint, parameter amendment. Experiments are also carried out on a real robot vision system to demonstrate the effectiveness of the proposed method. PMID:15369081

  1. Relativistic mean field model based on realistic nuclear forces

    SciTech Connect

    Hirose, S.; Serra, M.; Ring, P.; Otsuka, T.; Akaishi, Y.

    2007-02-15

    In order to predict properties of asymmetric nuclear matter, we construct a relativistic mean field (RMF) model consisting of one-meson exchange (OME) terms and point coupling (PC) terms. In order to determine the density dependent parameters of this model, we use properties of isospin symmetric nuclear matter in combination with the information on nucleon-nucleon scattering data, which are given in the form of the density dependent G-matrix derived from Brueckner calculations based on the Tamagaki potential. We show that the medium- and long-range components of this G-matrix can be described reasonably well by our effective OME interaction. In order to take into account the short-range part of the nucleon-nucleon interaction, which cannot be described well in this manner, a point coupling term is added. Its analytical form is taken from a model based on chiral perturbation theory. It contains only one additional parameter, which does not depend on the density. It is, together with the parameters of the OME potentials adjusted to the equation of state of symmetric nuclear matter. We apply this model for the investigation of asymmetric nuclear matter and find that the results for the symmetry energy as well as for the equation of state of pure neutron matter are in good agreement with either experimental data or with presently adopted theoretical predictions. In order to test the model at higher density, we use its equation of state for an investigation of properties of neutron stars.

  2. Propagating uncertainties in statistical model based shape prediction

    NASA Astrophysics Data System (ADS)

    Syrkina, Ekaterina; Blanc, Rémi; Székely, Gàbor

    2011-03-01

    This paper addresses the question of accuracy assessment and confidence regions estimation in statistical model based shape prediction. Shape prediction consists in estimating the shape of an organ based on a partial observation, due e.g. to a limited field of view or poorly contrasted images, and generally requires a statistical model. However, such predictions can be impaired by several sources of uncertainty, in particular the presence of noise in the observation, limited correlations between the predictors and the shape to predict, as well as limitations of the statistical shape model - in particular the number of training samples. We propose a framework which takes these into account and derives confidence regions around the predicted shape. Our method relies on the construction of two separate statistical shape models, for the predictors and for the unseen parts, and exploits the correlations between them assuming a joint Gaussian distribution. Limitations of the models are taken into account by jointly optimizing the prediction and minimizing the shape reconstruction error through cross-validation. An application to the prediction of the shape of the proximal part of the human tibia given the shape of the distal femur is proposed, as well as the evaluation of the reliability of the estimated confidence regions, using a database of 184 samples. Potential applications are reconstructive surgery, e.g. to assess whether an implant fits in a range of acceptable shapes, or functional neurosurgery when the target's position is not directly visible and needs to be inferred from nearby visible structures.

  3. Lithium battery aging model based on Dakin's degradation approach

    NASA Astrophysics Data System (ADS)

    Baghdadi, Issam; Briat, Olivier; Delétage, Jean-Yves; Gyan, Philippe; Vinassa, Jean-Michel

    2016-09-01

    This paper proposes and validates a calendar and power cycling aging model for two different lithium battery technologies. The model development is based on previous SIMCAL and SIMSTOCK project data. In these previous projects, the effect of the battery state of charge, temperature and current magnitude on aging was studied on a large panel of different battery chemistries. In this work, data are analyzed using Dakin's degradation approach. In fact, the logarithms of battery capacity fade and the increase in resistance evolves linearly over aging. The slopes identified from straight lines correspond to battery aging rates. Thus, a battery aging rate expression function of aging factors was deduced and found to be governed by Eyring's law. The proposed model simulates the capacity fade and resistance increase as functions of the influencing aging factors. Its expansion using Taylor series was consistent with semi-empirical models based on the square root of time, which are widely studied in the literature. Finally, the influence of the current magnitude and temperature on aging was simulated. Interestingly, the aging rate highly increases with decreasing and increasing temperature for the ranges of -5 °C-25 °C and 25 °C-60 °C, respectively.

  4. Model based condition monitoring in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Singh, Amardeep; Izadian, Afshin; Anwar, Sohel

    2014-12-01

    In this paper, a model based condition monitoring technique is developed for lithium-ion battery condition monitoring. Here a number of lithium-ion batteries are cycled using two separate over discharge test regimes and the resulting shift in battery parameters is recorded. The battery models are constructed using the equivalent circuit methodology. The condition monitoring setup consists of a model bank representing the different degree of parameter shift due to overdischarge in the lithium ion battery. Extended Kalman filters (EKF) are used to maintain increased robustness of the condition monitoring setup while estimating the terminal voltage of the battery cell. The information carrying residuals are generated and evaluation process is carried out in real-time using multiple model adaptive estimation (MMAE) methodology. The condition evaluation function is used to generate probabilities that indicate the presence of a particular operational condition. Using the test data, it is shown that the performance shift in lithium ion batteries due to over discharge can be accurately detected.

  5. Symbolic Processing Combined with Model-Based Reasoning

    NASA Technical Reports Server (NTRS)

    James, Mark

    2009-01-01

    A computer program for the detection of present and prediction of future discrete states of a complex, real-time engineering system utilizes a combination of symbolic processing and numerical model-based reasoning. One of the biggest weaknesses of a purely symbolic approach is that it enables prediction of only future discrete states while missing all unmodeled states or leading to incorrect identification of an unmodeled state as a modeled one. A purely numerical approach is based on a combination of statistical methods and mathematical models of the applicable physics and necessitates development of a complete model to the level of fidelity required for prediction. In addition, a purely numerical approach does not afford the ability to qualify its results without some form of symbolic processing. The present software implements numerical algorithms to detect unmodeled events and symbolic algorithms to predict expected behavior, correlate the expected behavior with the unmodeled events, and interpret the results in order to predict future discrete states. The approach embodied in this software differs from that of the BEAM methodology (aspects of which have been discussed in several prior NASA Tech Briefs articles), which provides for prediction of future measurements in the continuous-data domain.

  6. Femtosecond molecular dynamics of tautomerization in model base pairs

    NASA Astrophysics Data System (ADS)

    Douhal, A.; Kim, S. K.; Zewail, A. H.

    1995-11-01

    HYDROGEN bonds commonly lend robustness and directionality to molecular recognition processes and supramolecular structures1,2. In particular, the two or three hydrogen bonds in Watson-Crick base pairs bind the double-stranded DNA helix and determine the complementarity of the pairing. Watson and Crick pointed out3, however, that the possible tautomers of base pairs, in which hydrogen atoms become attached to the donor atom of the hydrogen bond, might disturb the genetic code, as the tautomer is capable of pairing with different partners. But the dynamics of hydrogen bonds in general, and of this tautomerization process in particular, are not well understood. Here we report observations of the femtosecond dynamics of tautomerization in model base pairs (7-azaindole dimers) containing two hydrogen bonds. Because of the femtosecond resolution of proton motions, we are able to examine the cooperativity of formation of the tautomer (in which the protons on each base are shifted sequentially to the other base), and to determine the characteristic timescales of the motions in a solvent-free environment. We find that the first step occurs on a timescale of a few hundred femtoseconds, whereas the second step, to form the full tautomer, is much slower, taking place within several picoseconds; the timescales are changed significantly by replacing hydrogen with deuterium. These results establish the molecular basis of the dynamics and the role of quantum tunnelling.

  7. Model-Based Material Parameter Estimation for Terahertz Reflection Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kniffin, Gabriel Paul

    Many materials such as drugs and explosives have characteristic spectral signatures in the terahertz (THz) band. These unique signatures imply great promise for spectral detection and classification using THz radiation. While such spectral features are most easily observed in transmission, real-life imaging systems will need to identify materials of interest from reflection measurements, often in non-ideal geometries. One important, yet commonly overlooked source of signal corruption is the etalon effect -- interference phenomena caused by multiple reflections from dielectric layers of packaging and clothing likely to be concealing materials of interest in real-life scenarios. This thesis focuses on the development and implementation of a model-based material parameter estimation technique, primarily for use in reflection spectroscopy, that takes the influence of the etalon effect into account. The technique is adapted from techniques developed for transmission spectroscopy of thin samples and is demonstrated using measured data taken at the Northwest Electromagnetic Research Laboratory (NEAR-Lab) at Portland State University. Further tests are conducted, demonstrating the technique's robustness against measurement noise and common sources of error.

  8. Tyre pressure monitoring using a dynamical model-based estimator

    NASA Astrophysics Data System (ADS)

    Reina, Giulio; Gentile, Angelo; Messina, Arcangelo

    2015-04-01

    In the last few years, various control systems have been investigated in the automotive field with the aim of increasing the level of safety and stability, avoid roll-over, and customise handling characteristics. One critical issue connected with their integration is the lack of state and parameter information. As an example, vehicle handling depends to a large extent on tyre inflation pressure. When inflation pressure drops, handling and comfort performance generally deteriorate. In addition, it results in an increase in fuel consumption and in a decrease in lifetime. Therefore, it is important to keep tyres within the normal inflation pressure range. This paper introduces a model-based approach to estimate online tyre inflation pressure. First, basic vertical dynamic modelling of the vehicle is discussed. Then, a parameter estimation framework for dynamic analysis is presented. Several important vehicle parameters including tyre inflation pressure can be estimated using the estimated states. This method aims to work during normal driving using information from standard sensors only. On the one hand, the driver is informed about the inflation pressure and he is warned for sudden changes. On the other hand, accurate estimation of the vehicle states is available as possible input to onboard control systems.

  9. Model-based sound synthesis of the guqin.

    PubMed

    Penttinen, Henri; Pakarinen, Jyri; Välimäki, Vesa; Laurson, Mikael; Li, Henbing; Leman, Marc

    2006-12-01

    This paper presents a model-based sound synthesis algorithm for the Chinese plucked string instrument called the guqin. The instrument is fretless, which enables smooth pitch glides from one note to another. A version of the digital waveguide synthesis approach is used, where the string length is time-varying and its energy is scaled properly. A body model filter is placed in cascade with the string model. Flageolet tones are synthesized with the so-called ripple filter structure, which is an FIR comb filter in the delay line of a digital waveguide model. In addition, signal analysis of recorded guqin tones is presented. Friction noise produced by gliding the finger across the soundboard has a harmonic structure and is proportional to the gliding speed. For pressed tones, one end of a vibrating string is terminated either by the nail of the thumb or a fingertip. The tones terminated with a fingertip decay faster than those terminated with a thumb. Guqin tones are slightly inharmonic and they exhibit phantom partials. The synthesis model takes into account these characteristic features of the instrument and is able to reproduce them. The synthesis model will be used for rule based synthesis of guqin music. PMID:17225431

  10. Advanced electron crystallography through model-based imaging

    PubMed Central

    Van Aert, Sandra; De Backer, Annick; Martinez, Gerardo T.; den Dekker, Arnold J.; Van Dyck, Dirk; Bals, Sara; Van Tendeloo, Gustaaf

    2016-01-01

    The increasing need for precise determination of the atomic arrangement of non-periodic structures in materials design and the control of nanostructures explains the growing interest in quantitative transmission electron microscopy. The aim is to extract precise and accurate numbers for unknown structure parameters including atomic positions, chemical concentrations and atomic numbers. For this purpose, statistical parameter estimation theory has been shown to provide reliable results. In this theory, observations are considered purely as data planes, from which structure parameters have to be determined using a parametric model describing the images. As such, the positions of atom columns can be measured with a precision of the order of a few picometres, even though the resolution of the electron microscope is still one or two orders of magnitude larger. Moreover, small differences in average atomic number, which cannot be distinguished visually, can be quantified using high-angle annular dark-field scanning transmission electron microscopy images. In addition, this theory allows one to measure compositional changes at interfaces, to count atoms with single-atom sensitivity, and to reconstruct atomic structures in three dimensions. This feature article brings the reader up to date, summarizing the underlying theory and highlighting some of the recent applications of quantitative model-based transmisson electron microscopy. PMID:26870383

  11. Model-Based Recursive Partitioning for Subgroup Analyses.

    PubMed

    Seibold, Heidi; Zeileis, Achim; Hothorn, Torsten

    2016-05-01

    The identification of patient subgroups with differential treatment effects is the first step towards individualised treatments. A current draft guideline by the EMA discusses potentials and problems in subgroup analyses and formulated challenges to the development of appropriate statistical procedures for the data-driven identification of patient subgroups. We introduce model-based recursive partitioning as a procedure for the automated detection of patient subgroups that are identifiable by predictive factors. The method starts with a model for the overall treatment effect as defined for the primary analysis in the study protocol and uses measures for detecting parameter instabilities in this treatment effect. The procedure produces a segmented model with differential treatment parameters corresponding to each patient subgroup. The subgroups are linked to predictive factors by means of a decision tree. The method is applied to the search for subgroups of patients suffering from amyotrophic lateral sclerosis that differ with respect to their Riluzole treatment effect, the only currently approved drug for this disease. PMID:27227717

  12. Improved knowledge diffusion model based on the collaboration hypernetwork

    NASA Astrophysics Data System (ADS)

    Wang, Jiang-Pan; Guo, Qiang; Yang, Guang-Yong; Liu, Jian-Guo

    2015-06-01

    The process for absorbing knowledge becomes an essential element for innovation in firms and in adapting to changes in the competitive environment. In this paper, we present an improved knowledge diffusion hypernetwork (IKDH) model based on the idea that knowledge will spread from the target node to all its neighbors in terms of the hyperedge and knowledge stock. We apply the average knowledge stock V(t) , the variable σ2(t) , and the variance coefficient c(t) to evaluate the performance of knowledge diffusion. By analyzing different knowledge diffusion ways, selection ways of the highly knowledgeable nodes, hypernetwork sizes and hypernetwork structures for the performance of knowledge diffusion, results show that the diffusion speed of IKDH model is 3.64 times faster than that of traditional knowledge diffusion (TKDH) model. Besides, it is three times faster to diffuse knowledge by randomly selecting "expert" nodes than that by selecting large-hyperdegree nodes as "expert" nodes. Furthermore, either the closer network structure or smaller network size results in the faster knowledge diffusion.

  13. a model based on crowsourcing for detecting natural hazards

    NASA Astrophysics Data System (ADS)

    Duan, J.; Ma, C.; Zhang, J.; Liu, S.; Liu, J.

    2015-12-01

    Remote Sensing Technology provides a new method for the detecting,early warning,mitigation and relief of natural hazards. Given the suddenness and the unpredictability of the location of natural hazards as well as the actual demands for hazards work, this article proposes an evaluation model for remote sensing detecting of natural hazards based on crowdsourcing. Firstly, using crowdsourcing model and with the help of the Internet and the power of hundreds of millions of Internet users, this evaluation model provides visual interpretation of high-resolution remote sensing images of hazards area and collects massive valuable disaster data; secondly, this evaluation model adopts the strategy of dynamic voting consistency to evaluate the disaster data provided by the crowdsourcing workers; thirdly, this evaluation model pre-estimates the disaster severity with the disaster pre-evaluation model based on regional buffers; lastly, the evaluation model actuates the corresponding expert system work according to the forecast results. The idea of this model breaks the boundaries between geographic information professionals and the public, makes the public participation and the citizen science eventually be realized, and improves the accuracy and timeliness of hazards assessment results.

  14. Electrochemical model based charge optimization for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Pramanik, Sourav; Anwar, Sohel

    2016-05-01

    In this paper, we propose the design of a novel optimal strategy for charging the lithium-ion battery based on electrochemical battery model that is aimed at improved performance. A performance index that aims at minimizing the charging effort along with a minimum deviation from the rated maximum thresholds for cell temperature and charging current has been defined. The method proposed in this paper aims at achieving a faster charging rate while maintaining safe limits for various battery parameters. Safe operation of the battery is achieved by including the battery bulk temperature as a control component in the performance index which is of critical importance for electric vehicles. Another important aspect of the performance objective proposed here is the efficiency of the algorithm that would allow higher charging rates without compromising the internal electrochemical kinetics of the battery which would prevent abusive conditions, thereby improving the long term durability. A more realistic model, based on battery electro-chemistry has been used for the design of the optimal algorithm as opposed to the conventional equivalent circuit models. To solve the optimization problem, Pontryagins principle has been used which is very effective for constrained optimization problems with both state and input constraints. Simulation results show that the proposed optimal charging algorithm is capable of shortening the charging time of a lithium ion cell while maintaining the temperature constraint when compared with the standard constant current charging. The designed method also maintains the internal states within limits that can avoid abusive operating conditions.

  15. Model-Based Systems Engineering in Concurrent Engineering Centers

    NASA Technical Reports Server (NTRS)

    Iwata, Curtis; Infeld, Samantha; Bracken, Jennifer Medlin; McGuire; McQuirk, Christina; Kisdi, Aron; Murphy, Jonathan; Cole, Bjorn; Zarifian, Pezhman

    2015-01-01

    Concurrent Engineering Centers (CECs) are specialized facilities with a goal of generating and maturing engineering designs by enabling rapid design iterations. This is accomplished by co-locating a team of experts (either physically or virtually) in a room with a focused design goal and a limited timeline of a week or less. The systems engineer uses a model of the system to capture the relevant interfaces and manage the overall architecture. A single model that integrates other design information and modeling allows the entire team to visualize the concurrent activity and identify conflicts more efficiently, potentially resulting in a systems model that will continue to be used throughout the project lifecycle. Performing systems engineering using such a system model is the definition of model-based systems engineering (MBSE); therefore, CECs evolving their approach to incorporate advances in MBSE are more successful in reducing time and cost needed to meet study goals. This paper surveys space mission CECs that are in the middle of this evolution, and the authors share their experiences in order to promote discussion within the community.

  16. Model-Based Systems Engineering in Concurrent Engineering Centers

    NASA Technical Reports Server (NTRS)

    Iwata, Curtis; Infeld, Samatha; Bracken, Jennifer Medlin; McGuire, Melissa; McQuirk, Christina; Kisdi, Aron; Murphy, Jonathan; Cole, Bjorn; Zarifian, Pezhman

    2015-01-01

    Concurrent Engineering Centers (CECs) are specialized facilities with a goal of generating and maturing engineering designs by enabling rapid design iterations. This is accomplished by co-locating a team of experts (either physically or virtually) in a room with a narrow design goal and a limited timeline of a week or less. The systems engineer uses a model of the system to capture the relevant interfaces and manage the overall architecture. A single model that integrates other design information and modeling allows the entire team to visualize the concurrent activity and identify conflicts more efficiently, potentially resulting in a systems model that will continue to be used throughout the project lifecycle. Performing systems engineering using such a system model is the definition of model-based systems engineering (MBSE); therefore, CECs evolving their approach to incorporate advances in MBSE are more successful in reducing time and cost needed to meet study goals. This paper surveys space mission CECs that are in the middle of this evolution, and the authors share their experiences in order to promote discussion within the community.

  17. An application of model-based reasoning to accounting systems

    SciTech Connect

    Nado, R.; Chams, M.; Delisio, J.; Hamscher, W.

    1996-12-31

    An important problem faced by auditors is gauging how much reliance can be placed on the accounting systems that process millions of transactions to produce the numbers summarized in a company`s financial statements. Accounting systems contain internal controls, procedures designed to detect and correct errors and irregularities that may occur in the processing of transactions. In a complex accounting system, it can be an extremely difficult task for the auditor to anticipate the possible errors that can occur and to evaluate the effectiveness of the controls at detecting them. An accurate analysis must take into account the unique features of each company`s business processes. To cope with this complexity and variability, the Comet system applies a model-based reasoning approach to the analysis of accounting systems and their controls. An auditor uses Comet to create a hierarchical flowchart model that describes the intended processing of business transactions by an accounting system and the operation of its controls. Comet uses the constructed model to automatically analyze the effectiveness of the controls in detecting potential errors. Price Waterhouse auditors have used Comet on a variety of real audits in several countries around the world.

  18. Model-Based Verification and Validation of Spacecraft Avionics

    NASA Technical Reports Server (NTRS)

    Khan, M. Omair; Sievers, Michael; Standley, Shaun

    2012-01-01

    Verification and Validation (V&V) at JPL is traditionally performed on flight or flight-like hardware running flight software. For some time, the complexity of avionics has increased exponentially while the time allocated for system integration and associated V&V testing has remained fixed. There is an increasing need to perform comprehensive system level V&V using modeling and simulation, and to use scarce hardware testing time to validate models; the norm for thermal and structural V&V for some time. Our approach extends model-based V&V to electronics and software through functional and structural models implemented in SysML. We develop component models of electronics and software that are validated by comparison with test results from actual equipment. The models are then simulated enabling a more complete set of test cases than possible on flight hardware. SysML simulations provide access and control of internal nodes that may not be available in physical systems. This is particularly helpful in testing fault protection behaviors when injecting faults is either not possible or potentially damaging to the hardware. We can also model both hardware and software behaviors in SysML, which allows us to simulate hardware and software interactions. With an integrated model and simulation capability we can evaluate the hardware and software interactions and identify problems sooner. The primary missing piece is validating SysML model correctness against hardware; this experiment demonstrated such an approach is possible.

  19. Measuring neuronal branching patterns using model-based approach.

    PubMed

    Luczak, Artur

    2010-01-01

    Neurons have complex branching systems which allow them to communicate with thousands of other neurons. Thus understanding neuronal geometry is clearly important for determining connectivity within the network and how this shapes neuronal function. One of the difficulties in uncovering relationships between neuronal shape and its function is the problem of quantifying complex neuronal geometry. Even by using multiple measures such as: dendritic length, distribution of segments, direction of branches, etc, a description of three dimensional neuronal embedding remains incomplete. To help alleviate this problem, here we propose a new measure, a shape diffusiveness index (SDI), to quantify spatial relations between branches at the local and global scale. It was shown that growth of neuronal trees can be modeled by using diffusion limited aggregation (DLA) process. By measuring "how easy" it is to reproduce the analyzed shape by using the DLA algorithm it can be measured how "diffusive" is that shape. Intuitively, "diffusiveness" measures how tree-like is a given shape. For example shapes like an oak tree will have high values of SDI. This measure is capturing an important feature of dendritic tree geometry, which is difficult to assess with other measures. This approach also presents a paradigm shift from well-defined deterministic measures to model-based measures, which estimate how well a model with specific properties can account for features of analyzed shape. PMID:21079752

  20. PARALLELISATION OF THE MODEL-BASED ITERATIVE RECONSTRUCTION ALGORITHM DIRA.

    PubMed

    Örtenberg, A; Magnusson, M; Sandborg, M; Alm Carlsson, G; Malusek, A

    2016-06-01

    New paradigms for parallel programming have been devised to simplify software development on multi-core processors and many-core graphical processing units (GPU). Despite their obvious benefits, the parallelisation of existing computer programs is not an easy task. In this work, the use of the Open Multiprocessing (OpenMP) and Open Computing Language (OpenCL) frameworks is considered for the parallelisation of the model-based iterative reconstruction algorithm DIRA with the aim to significantly shorten the code's execution time. Selected routines were parallelised using OpenMP and OpenCL libraries; some routines were converted from MATLAB to C and optimised. Parallelisation of the code with the OpenMP was easy and resulted in an overall speedup of 15 on a 16-core computer. Parallelisation with OpenCL was more difficult owing to differences between the central processing unit and GPU architectures. The resulting speedup was substantially lower than the theoretical peak performance of the GPU; the cause was explained. PMID:26454270

  1. Connectionist model-based stereo vision for telerobotics

    NASA Technical Reports Server (NTRS)

    Hoff, William; Mathis, Donald

    1989-01-01

    Autonomous stereo vision for range measurement could greatly enhance the performance of telerobotic systems. Stereo vision could be a key component for autonomous object recognition and localization, thus enabling the system to perform low-level tasks, and allowing a human operator to perform a supervisory role. The central difficulty in stereo vision is the ambiguity in matching corresponding points in the left and right images. However, if one has a priori knowledge of the characteristics of the objects in the scene, as is often the case in telerobotics, a model-based approach can be taken. Researchers describe how matching ambiguities can be resolved by ensuring that the resulting three-dimensional points are consistent with surface models of the expected objects. A four-layer neural network hierarchy is used in which surface models of increasing complexity are represented in successive layers. These models are represented using a connectionist scheme called parameter networks, in which a parametrized object (for example, a planar patch p=f(h,m sub x, m sub y) is represented by a collection of processing units, each of which corresponds to a distinct combination of parameter values. The activity level of each unit in the parameter network can be thought of as representing the confidence with which the hypothesis represented by that unit is believed. Weights in the network are set so as to implement gradient descent in an energy function.

  2. Model-based engineering for laser weapons systems

    NASA Astrophysics Data System (ADS)

    Panthaki, Malcolm; Coy, Steve

    2011-10-01

    The Comet Performance Engineering Workspace is an environment that enables integrated, multidisciplinary modeling and design/simulation process automation. One of the many multi-disciplinary applications of the Comet Workspace is for the integrated Structural, Thermal, Optical Performance (STOP) analysis of complex, multi-disciplinary space systems containing Electro-Optical (EO) sensors such as those which are designed and developed by and for NASA and the Department of Defense. The CometTM software is currently able to integrate performance simulation data and processes from a wide range of 3-D CAD and analysis software programs including CODE VTM from Optical Research Associates and SigFitTM from Sigmadyne Inc. which are used to simulate the optics performance of EO sensor systems in space-borne applications. Over the past year, Comet Solutions has been working with MZA Associates of Albuquerque, NM, under a contract with the Air Force Research Laboratories. This funded effort is a "risk reduction effort", to help determine whether the combination of Comet and WaveTrainTM, a wave optics systems engineering analysis environment developed and maintained by MZA Associates and used by the Air Force Research Laboratory, will result in an effective Model-Based Engineering (MBE) environment for the analysis and design of laser weapons systems. This paper will review the results of this effort and future steps.

  3. PACS model based on digital watermarking and its core algorithms

    NASA Astrophysics Data System (ADS)

    Que, Dashun; Wen, Xianlin; Chen, Bi

    2009-10-01

    PACS model based on digital watermarking is proposed by analyzing medical image features and PACS requirements from the point of view of information security, its core being digital watermarking server and the corresponding processing module. Two kinds of digital watermarking algorithm are studied; one is non-region of interest (NROI) digital watermarking algorithm based on wavelet domain and block-mean, the other is reversible watermarking algorithm on extended difference and pseudo-random matrix. The former belongs to robust lossy watermarking, which embedded in NROI by wavelet provides a good way for protecting the focus area (ROI) of images, and introduction of block-mean approach a good scheme to enhance the anti-attack capability; the latter belongs to fragile lossless watermarking, which has the performance of simple implementation and can realize tamper localization effectively, and the pseudo-random matrix enhances the correlation and security between pixels. Plenty of experimental research has been completed in this paper, including the realization of digital watermarking PACS model, the watermarking processing module and its anti-attack experiments, the digital watermarking server and the network transmission simulating experiments of medical images. Theoretical analysis and experimental results show that the designed PACS model can effectively ensure confidentiality, authenticity, integrity and security of medical image information.

  4. Discrete-Time ARMAv Model-Based Optimal Sensor Placement

    SciTech Connect

    Song Wei; Dyke, Shirley J.

    2008-07-08

    This paper concentrates on the optimal sensor placement problem in ambient vibration based structural health monitoring. More specifically, the paper examines the covariance of estimated parameters during system identification using auto-regressive and moving average vector (ARMAv) model. By utilizing the discrete-time steady state Kalman filter, this paper realizes the structure's finite element (FE) model under broad-band white noise excitations using an ARMAv model. Based on the asymptotic distribution of the parameter estimates of the ARMAv model, both a theoretical closed form and a numerical estimate form of the covariance of the estimates are obtained. Introducing the information entropy (differential entropy) measure, as well as various matrix norms, this paper attempts to find a reasonable measure to the uncertainties embedded in the ARMAv model estimates. Thus, it is possible to select the optimal sensor placement that would lead to the smallest uncertainties during the ARMAv identification process. Two numerical examples are provided to demonstrate the methodology and compare the sensor placement results upon various measures.

  5. Model-Based Reasoning in Upper-division Lab Courses

    NASA Astrophysics Data System (ADS)

    Lewandowski, Heather

    2015-05-01

    Modeling, which includes developing, testing, and refining models, is a central activity in physics. Well-known examples from AMO physics include everything from the Bohr model of the hydrogen atom to the Bose-Hubbard model of interacting bosons in a lattice. Modeling, while typically considered a theoretical activity, is most fully represented in the laboratory where measurements of real phenomena intersect with theoretical models, leading to refinement of models and experimental apparatus. However, experimental physicists use models in complex ways and the process is often not made explicit in physics laboratory courses. We have developed a framework to describe the modeling process in physics laboratory activities. The framework attempts to abstract and simplify the complex modeling process undertaken by expert experimentalists. The framework can be applied to understand typical processes such the modeling of the measurement tools, modeling ``black boxes,'' and signal processing. We demonstrate that the framework captures several important features of model-based reasoning in a way that can reveal common student difficulties in the lab and guide the development of curricula that emphasize modeling in the laboratory. We also use the framework to examine troubleshooting in the lab and guide students to effective methods and strategies.

  6. An Opinion Interactive Model Based on Individual Persuasiveness

    PubMed Central

    Zhou, Xin; Chen, Bin; Liu, Liang; Ma, Liang; Qiu, Xiaogang

    2015-01-01

    In order to study the formation process of group opinion in real life, we put forward a new opinion interactive model based on Deffuant model and its improved models in this paper because current models of opinion dynamics lack considering individual persuasiveness. Our model has following advantages: firstly persuasiveness is added to individual's attributes reflecting the importance of persuasiveness, which means that all the individuals are different from others; secondly probability is introduced in the course of interaction which simulates the uncertainty of interaction. In Monte Carlo simulation experiments, sensitivity analysis including the influence of randomness, initial persuasiveness distribution, and number of individuals is studied at first; what comes next is that the range of common opinion based on the initial persuasiveness distribution can be predicted. Simulation experiment results show that when the initial values of agents are fixed, no matter how many times independently replicated experiments, the common opinion will converge at a certain point; however the number of iterations will not always be the same; the range of common opinion can be predicted when initial distribution of opinion and persuasiveness are given. As a result, this model can reflect and interpret some phenomena of opinion interaction in realistic society. PMID:26508911

  7. Multi-Pin Studies of the Effect of Changes in PWR Fuel Design on Clad Ballooning and Flow Blockage in a Large-Break Loss-Of Coolant Accident

    SciTech Connect

    Jones, J.R.; Trow, M.

    2007-07-01

    Fuel pins can credibly balloon to reach very high diametric strains under temperature transients typical of a PWR Loss-of coolant Accident (LOCA), but experiments show that these balloons are sufficiently misaligned axially to prevent total blockage of the flow. Most of the relevant experiments were performed in the 1980's and therefore were principally carried out on the various forms of Zircaloy 4 cladding available at the time. Much of the fuel used was either fresh or of modest burnup compared to the discharge irradiations achievable today. Since then, single pin experiments have been carried out with new cladding material and (to a limited extent) with high-burnup fuel. However, there is a need to interpret the performance of this fuel in the context of the wider body of evidence. A model of the development of flow blockages has been implemented using multiple instances of the fuel pin code MABEL interfaced to a sub-channel coolant flow code. The effect of a change in cladding material from Zircaloy to a 1% niobium alloy has been examined. The assessment concluded that the proposed replacement alloy is more creep hard at high temperature and therefore is expected to fail slightly later in the transient. The new cladding achieved a generally lower diametric strain at failure under the particular conditions of the fault. (authors)

  8. Model-Based Engineering and Manufacturing CAD/CAM Benchmark

    SciTech Connect

    Domm, T.D.; Underwood, R.S.

    1999-04-26

    The Benehmark Project was created from a desire to identify best practices and improve the overall efficiency and performance of the Y-12 Plant's systems and personnel supprting the manufacturing mission. The mission of the benchmark team was to search out industry leaders in manufacturing and evaluate lheir engineering practices and processes to determine direction and focus fm Y-12 modmizadon efforts. The companies visited included several large established companies and anew, small, high-tech machining firm. As a result of this efforL changes are recommended that will enable Y-12 to become a more responsive cost-effective manufacturing facility capable of suppordng the needs of the Nuclear Weapons Complex (NW@) and Work Fw Others into the 21' century. The benchmark team identified key areas of interest, both focused and gencml. The focus arm included Human Resources, Information Management, Manufacturing Software Tools, and Standarda/ Policies and Practices. Areas of general interest included Inhstructure, Computer Platforms and Networking, and Organizational Structure. The method for obtaining the desired information in these areas centered on the creation of a benchmark questionnaire. The questionnaire was used throughout each of the visits as the basis for information gathering. The results of this benchmark showed that all companies are moving in the direction of model-based engineering and manufacturing. There was evidence that many companies are trying to grasp how to manage current and legacy data. In terms of engineering design software tools, the companies contacted were using both 3-D solid modeling and surfaced Wire-frame models. The manufacturing computer tools were varie4 with most companies using more than one software product to generate machining data and none currently performing model-based manufacturing (MBM) ftom a common medel. The majority of companies were closer to identifying or using a single computer-aided design (CAD) system than a

  9. Probabilistic model-based approach for heart beat detection.

    PubMed

    Chen, Hugh; Erol, Yusuf; Shen, Eric; Russell, Stuart

    2016-09-01

    Nowadays, hospitals are ubiquitous and integral to modern society. Patients flow in and out of a veritable whirlwind of paperwork, consultations, and potential inpatient admissions, through an abstracted system that is not without flaws. One of the biggest flaws in the medical system is perhaps an unexpected one: the patient alarm system. One longitudinal study reported an 88.8% rate of false alarms, with other studies reporting numbers of similar magnitudes. These false alarm rates lead to deleterious effects that manifest in a lower standard of care across clinics. This paper discusses a model-based probabilistic inference approach to estimate physiological variables at a detection level. We design a generative model that complies with a layman's understanding of human physiology and perform approximate Bayesian inference. One primary goal of this paper is to justify a Bayesian modeling approach to increasing robustness in a physiological domain. In order to evaluate our algorithm we look at the application of heart beat detection using four datasets provided by PhysioNet, a research resource for complex physiological signals, in the form of the PhysioNet 2014 Challenge set-p1 and set-p2, the MIT-BIH Polysomnographic Database, and the MGH/MF Waveform Database. On these data sets our algorithm performs on par with the other top six submissions to the PhysioNet 2014 challenge. The overall evaluation scores in terms of sensitivity and positive predictivity values obtained were as follows: set-p1 (99.72%), set-p2 (93.51%), MIT-BIH (99.66%), and MGH/MF (95.53%). These scores are based on the averaging of gross sensitivity, gross positive predictivity, average sensitivity, and average positive predictivity. PMID:27480267

  10. Medical Device Integration Model Based on the Internet of Things

    PubMed Central

    Hao, Aiyu; Wang, Ling

    2015-01-01

    At present, hospitals in our country have basically established the HIS system, which manages registration, treatment, and charge, among many others, of patients. During treatment, patients need to use medical devices repeatedly to acquire all sorts of inspection data. Currently, the output data of the medical devices are often manually input into information system, which is easy to get wrong or easy to cause mismatches between inspection reports and patients. For some small hospitals of which information construction is still relatively weak, the information generated by the devices is still presented in the form of paper reports. When doctors or patients want to have access to the data at a given time again, they can only look at the paper files. Data integration between medical devices has long been a difficult problem for the medical information system, because the data from medical devices are lack of mandatory unified global standards and have outstanding heterogeneity of devices. In order to protect their own interests, manufacturers use special protocols, etc., thus causing medical decices to still be the "lonely island" of hospital information system. Besides, unfocused application of the data will lead to failure to achieve a reasonable distribution of medical resources. With the deepening of IT construction in hospitals, medical information systems will be bound to develop towards mobile applications, intelligent analysis, and interconnection and interworking, on the premise that there is an effective medical device integration (MDI) technology. To this end, this paper presents a MDI model based on the Internet of Things (IoT). Through abstract classification, this model is able to extract the common characteristics of the devices, resolve the heterogeneous differences between them, and employ a unified protocol to integrate data between devices. And by the IoT technology, it realizes interconnection network of devices and conducts associate matching

  11. An integrated model-based neurosurgical guidance system

    NASA Astrophysics Data System (ADS)

    Ji, Songbai; Fan, Xiaoyao; Fontaine, Kathryn; Hartov, Alex; Roberts, David; Paulsen, Keith

    2010-02-01

    Maximal tumor resection without damaging healthy tissue in open cranial surgeries is critical to the prognosis for patients with brain cancers. Preoperative images (e.g., preoperative magnetic resonance images (pMR)) are typically used for surgical planning as well as for intraoperative image-guidance. However, brain shift even at the start of surgery significantly compromises the accuracy of neuronavigation, if the deformation is not compensated for. Compensating for brain shift during surgical operation is, therefore, critical for improving the accuracy of image-guidance and ultimately, the accuracy of surgery. To this end, we have developed an integrated neurosurgical guidance system that incorporates intraoperative three-dimensional (3D) tracking, acquisition of volumetric true 3D ultrasound (iUS), stereovision (iSV) and computational modeling to efficiently generate model-updated MR image volumes for neurosurgical guidance. The system is implemented with real-time Labview to provide high efficiency in data acquisition as well as with Matlab to offer computational convenience in data processing and development of graphical user interfaces related to computational modeling. In a typical patient case, the patient in the operating room (OR) is first registered to pMR image volume. Sparse displacement data extracted from coregistered intraoperative US and/or stereovision images are employed to guide a computational model that is based on consolidation theory. Computed whole-brain deformation is then used to generate a model-updated MR image volume for subsequent surgical guidance. In this paper, we present the key modular components of our integrated, model-based neurosurgical guidance system.

  12. A Kp forecast model based on neural network

    NASA Astrophysics Data System (ADS)

    Gong, J.; Liu, Y.; Luo, B.; Liu, S.

    2013-12-01

    As an important global geomagnetic disturbance index, Kp is difficult to predict, especially when Kp reaches 5 which means that the disturbance has reached the scales of geomagnetic storm and can cause spacecraft and power system anomaly. Statistical results showed that there exists high correlation between solar wind-magnetosphere coupling function and Kp index, and a linear combination of two solar wind-magnetosphere coupling terms, merging term and viscous term, proved to be good in predicting the Kp index. In this study, using the upstream solar wind parameters by the ACE satellite since 1998 and the two derived coupling terms mentioned above, a Kp forecast model based on artificial neural network is developed. For the operational need of predicting the geomagnetic disturbance as soon as possible, we construct the solar wind data and develop the model in an innovative way. For each Kp value at time t (the universal times of 8 Kp values in each day are noted as t=3, 6, 9, ..., 18, 21, 24), the model gives 6 predicted values every half an hour at t-3.5, t-3.0, t-2.5, t-2.0, t-1.5, t-1.0, based on the half-hour averaged model inputs (solar wind parameters and derived solar wind-magnetosphere coupling terms). The last predicted value at t-1.0 provides the final prediction. Evaluated with the test set data including years 1998, 2002 and 2006, the model yields the linear correlation coefficient (LC) of 0.88 and the root mean square error (RMSE) of 0.65 between the modeled and observed Kp values. Furthermore, if the nowcast Kp is available and included in the model input, the model can be improved and gives an LC of 0.90 and an RMSE of 0.62.

  13. Model-based development of neuroprosthesis for paraplegic patients.

    PubMed Central

    Riener, R

    1999-01-01

    In paraplegic patients with upper motor neuron lesions the signal path from the central nervous system to the muscles is interrupted. Functional electrical stimulation applied to the lower motor neurons can replace the lacking signals. A so-called neuroprosthesis may be used to restore motor function in paraplegic patients on the basis of functional electrical stimulation. However, the control of multiple joints is difficult due to the complexity, nonlinearity, and time-variance of the system involved. Furthermore, effects such as muscle fatigue, spasticity, and limited force in the stimulated muscle further complicate the control task. Mathematical models of the human musculoskeletal system can support the development of neuroprosthesis. In this article a detailed overview of the existing work in the literature is given and two examples developed by the author are presented that give an insight into model-based development of neuroprosthesis for paraplegic patients. It is shown that modelling the musculoskeletal system can provide better understanding of muscular force production and movement coordination principles. Models can also be used to design and test stimulation patterns and feedback control strategies. Additionally, model components can be implemented in a controller to improve control performance. Eventually, the use of musculoskeletal models for neuroprosthesis design may help to avoid internal disturbances such as fatigue and optimize muscular force output. Furthermore, better controller quality can be obtained than in previous empirical approaches. In addition, the number of experimental tests to be performed with human subjects can be reduced. It is concluded that mathematical models play an increasing role in the development of reliable closed-loop controlled, lower extremity neuroprostheses. PMID:10382222

  14. Model-based damage evaluation of layered CFRP structures

    NASA Astrophysics Data System (ADS)

    Munoz, Rafael; Bochud, Nicolas; Rus, Guillermo; Peralta, Laura; Melchor, Juan; Chiachío, Juan; Chiachío, Manuel; Bond, Leonard J.

    2015-03-01

    An ultrasonic evaluation technique for damage identification of layered CFRP structures is presented. This approach relies on a model-based estimation procedure that combines experimental data and simulation of ultrasonic damage-propagation interactions. The CFPR structure, a [0/90]4s lay-up, has been tested in an immersion through transmission experiment, where a scan has been performed on a damaged specimen. Most ultrasonic techniques in industrial practice consider only a few features of the received signals, namely, time of flight, amplitude, attenuation, frequency contents, and so forth. In this case, once signals are captured, an algorithm is used to reconstruct the complete signal waveform and extract the unknown damage parameters by means of modeling procedures. A linear version of the data processing has been performed, where only Young modulus has been monitored and, in a second nonlinear version, the first order nonlinear coefficient β was incorporated to test the possibility of detection of early damage. The aforementioned physical simulation models are solved by the Transfer Matrix formalism, which has been extended from linear to nonlinear harmonic generation technique. The damage parameter search strategy is based on minimizing the mismatch between the captured and simulated signals in the time domain in an automated way using Genetic Algorithms. Processing all scanned locations, a C-scan of the parameter of each layer can be reconstructed, obtaining the information describing the state of each layer and each interface. Damage can be located and quantified in terms of changes in the selected parameter with a measurable extension. In the case of the nonlinear coefficient of first order, evidence of higher sensitivity to damage than imaging the linearly estimated Young Modulus is provided.

  15. Model Based Systems Engineering on the Europa Mission Concept Study

    NASA Technical Reports Server (NTRS)

    Bayer, Todd J.; Chung, Seung; Cole, Bjorn; Cooke, Brian; Dekens, Frank; Delp, Chris; Gontijo, I.; Lewis, Kari; Moshir, Mehrdad; Rasmussen, Robert; Wagner, Dave

    2012-01-01

    At the start of 2011, the proposed Jupiter Europa Orbiter (JEO) mission was staffing up in expectation of becoming an official project later in the year for a launch in 2020. A unique aspect of the pre-project work was a strong emphasis and investment on the foundations of Model-Based Systems Engineering (MBSE). As so often happens in this business, plans changed: NASA's budget and science priorities were released and together fundamentally changed the course of JEO. As a result, it returned to being a study task whose objective is to propose more affordable ways to accomplish the science. As part of this transition, the question arose as to whether it could continue to afford the investment in MBSE. In short, the MBSE infusion has survived and is providing clear value to the study effort. By leveraging the existing infrastructure and a modest additional investment, striking advances in the capture and analysis of designs using MBSE were achieved. In the process, the need to remain relevant in the new environment has brought about a wave of innovation and progress. The effort has reaffirmed the importance of architecting. It has successfully harnessed the synergistic relationship of architecting to system modeling. We have found that MBSE can provide greater agility than traditional methods. We have also found that a diverse 'ecosystem' of modeling tools and languages (SysML, Mathematica, even Excel) is not only viable, but an important enabler of agility and adaptability. This paper will describe the successful application of MBSE in the dynamic environment of early mission formulation, the significant results produced and lessons learned in the process.

  16. Research on infrared imaging illumination model based on materials

    NASA Astrophysics Data System (ADS)

    Hu, Hai-he; Feng, Chao-yin; Guo, Chang-geng; Zheng, Hai-jing; Han, Qiang; Hu, Hai-yan

    2013-09-01

    In order to effectively simulate infrared features of the scene and infrared high light phenomenon, Based on the visual light illumination model, according to the optical property of all material types in the scene, the infrared imaging illumination models are proposed to fulfill different materials: to the smooth material with specular characteristic, adopting the infrared imaging illumination model based on Blinn-Phone reflection model and introducing the self emission; to the ordinary material which is similar to black body without highlight feature, ignoring the computation of its high light reflection feature, calculating simply the material's self emission and its reflection to the surrounding as its infrared imaging illumination model, the radiation energy under zero range of visibility can be obtained according to the above two models. The OpenGl rendering technology is used to construct infrared scene simulation system which can also simulate infrared electro-optical imaging system, then gets the synthetic infrared images from any angle of view of the 3D scenes. To validate the infrared imaging illumination model, two typical 3D scenes are made, and their infrared images are calculated to compare and contrast with the real collected infrared images obtained by a long wave infrared band imaging camera. There are two major points in the paper according to the experiment results: firstly, the infrared imaging illumination models are capable of producing infrared images which are very similar to those received by thermal infrared camera; secondly, the infrared imaging illumination models can simulate the infrared specular feature of relative materials and common infrared features of general materials, which shows the validation of the infrared imaging illumination models. Quantitative analysis shows that the simulation images are similar to the collected images in the aspects of main features, but their histogram distribution does not match very well, the

  17. Model-based lamotrigine clearance changes during pregnancy: clinical implication

    PubMed Central

    Polepally, Akshanth R; Pennell, Page B; Brundage, Richard C; Stowe, Zachary N; Newport, Donald J; Viguera, Adele C; Ritchie, James C; Birnbaum, Angela K

    2014-01-01

    Objective The objective of the study was to characterize changes in the oral clearance (CL/F) of lamotrigine (LTG) over the course of pregnancy and the postpartum period through a model-based approach incorporating clinical characteristics that may influence CL/F, in support of developing clinical management guidelines. Methods Women receiving LTG therapy who were pregnant or planning pregnancy were enrolled. Maternal blood samples were collected at each visit. A pharmacokinetic analysis was performed using a population-based, nonlinear, mixed-effects model. Results A total of 600 LTG concentrations from 60 women (64 pregnancies) were included. The baseline LTG CL/F was 2.16 L/h with a between-subject variability of 40.6%. The influence of pregnancy on CL/F was described by gestational week. Two subpopulations of women emerged based on the rate of increase in LTG CL/F during pregnancy. The gestational age-associated increase in CL/F displayed a 10-fold higher rate in 77% of the women (0.118 L/h per week) compared to 23% (0.0115 L/h per week). The between-subject variability in these slopes was 43.0%. The increased CL/F at delivery declined to baseline values with a half-life of 0.55 weeks. Interpretation The majority of women had a substantial increase in CL/F from 2.16 to 6.88 L/h by the end of pregnancy, whereas 23% of women had a minimal increase. An increase in CL/F may correspond to decreases in LTG blood concentrations necessitating the need for more frequent dosage adjustments and closer monitoring in some pregnant women with epilepsy. Postpartum doses should be tapered to preconception dose ranges within 3 weeks of delivery. PMID:24883336

  18. Medical Device Integration Model Based on the Internet of Things.

    PubMed

    Hao, Aiyu; Wang, Ling

    2015-01-01

    At present, hospitals in our country have basically established the HIS system, which manages registration, treatment, and charge, among many others, of patients. During treatment, patients need to use medical devices repeatedly to acquire all sorts of inspection data. Currently, the output data of the medical devices are often manually input into information system, which is easy to get wrong or easy to cause mismatches between inspection reports and patients. For some small hospitals of which information construction is still relatively weak, the information generated by the devices is still presented in the form of paper reports. When doctors or patients want to have access to the data at a given time again, they can only look at the paper files. Data integration between medical devices has long been a difficult problem for the medical information system, because the data from medical devices are lack of mandatory unified global standards and have outstanding heterogeneity of devices. In order to protect their own interests, manufacturers use special protocols, etc., thus causing medical decices to still be the "lonely island" of hospital information system. Besides, unfocused application of the data will lead to failure to achieve a reasonable distribution of medical resources. With the deepening of IT construction in hospitals, medical information systems will be bound to develop towards mobile applications, intelligent analysis, and interconnection and interworking, on the premise that there is an effective medical device integration (MDI) technology. To this end, this paper presents a MDI model based on the Internet of Things (IoT). Through abstract classification, this model is able to extract the common characteristics of the devices, resolve the heterogeneous differences between them, and employ a unified protocol to integrate data between devices. And by the IoT technology, it realizes interconnection network of devices and conducts associate matching

  19. MACE: model based analysis of ChIP-exo.

    PubMed

    Wang, Liguo; Chen, Junsheng; Wang, Chen; Uusküla-Reimand, Liis; Chen, Kaifu; Medina-Rivera, Alejandra; Young, Edwin J; Zimmermann, Michael T; Yan, Huihuang; Sun, Zhifu; Zhang, Yuji; Wu, Stephen T; Huang, Haojie; Wilson, Michael D; Kocher, Jean-Pierre A; Li, Wei

    2014-11-10

    Understanding the role of a given transcription factor (TF) in regulating gene expression requires precise mapping of its binding sites in the genome. Chromatin immunoprecipitation-exo, an emerging technique using λ exonuclease to digest TF unbound DNA after ChIP, is designed to reveal transcription factor binding site (TFBS) boundaries with near-single nucleotide resolution. Although ChIP-exo promises deeper insights into transcription regulation, no dedicated bioinformatics tool exists to leverage its advantages. Most ChIP-seq and ChIP-chip analytic methods are not tailored for ChIP-exo, and thus cannot take full advantage of high-resolution ChIP-exo data. Here we describe a novel analysis framework, termed MACE (model-based analysis of ChIP-exo) dedicated to ChIP-exo data analysis. The MACE workflow consists of four steps: (i) sequencing data normalization and bias correction; (ii) signal consolidation and noise reduction; (iii) single-nucleotide resolution border peak detection using the Chebyshev Inequality and (iv) border matching using the Gale-Shapley stable matching algorithm. When applied to published human CTCF, yeast Reb1 and our own mouse ONECUT1/HNF6 ChIP-exo data, MACE is able to define TFBSs with high sensitivity, specificity and spatial resolution, as evidenced by multiple criteria including motif enrichment, sequence conservation, direct sequence pileup, nucleosome positioning and open chromatin states. In addition, we show that the fundamental advance of MACE is the identification of two boundaries of a TFBS with high resolution, whereas other methods only report a single location of the same event. The two boundaries help elucidate the in vivo binding structure of a given TF, e.g. whether the TF may bind as dimers or in a complex with other co-factors. PMID:25249628

  20. MACE: model based analysis of ChIP-exo

    PubMed Central

    Wang, Liguo; Chen, Junsheng; Wang, Chen; Uusküla-Reimand, Liis; Chen, Kaifu; Medina-Rivera, Alejandra; Young, Edwin J.; Zimmermann, Michael T.; Yan, Huihuang; Sun, Zhifu; Zhang, Yuji; Wu, Stephen T.; Huang, Haojie; Wilson, Michael D.; Kocher, Jean-Pierre A.; Li, Wei

    2014-01-01

    Understanding the role of a given transcription factor (TF) in regulating gene expression requires precise mapping of its binding sites in the genome. Chromatin immunoprecipitation-exo, an emerging technique using λ exonuclease to digest TF unbound DNA after ChIP, is designed to reveal transcription factor binding site (TFBS) boundaries with near-single nucleotide resolution. Although ChIP-exo promises deeper insights into transcription regulation, no dedicated bioinformatics tool exists to leverage its advantages. Most ChIP-seq and ChIP-chip analytic methods are not tailored for ChIP-exo, and thus cannot take full advantage of high-resolution ChIP-exo data. Here we describe a novel analysis framework, termed MACE (model-based analysis of ChIP-exo) dedicated to ChIP-exo data analysis. The MACE workflow consists of four steps: (i) sequencing data normalization and bias correction; (ii) signal consolidation and noise reduction; (iii) single-nucleotide resolution border peak detection using the Chebyshev Inequality and (iv) border matching using the Gale-Shapley stable matching algorithm. When applied to published human CTCF, yeast Reb1 and our own mouse ONECUT1/HNF6 ChIP-exo data, MACE is able to define TFBSs with high sensitivity, specificity and spatial resolution, as evidenced by multiple criteria including motif enrichment, sequence conservation, direct sequence pileup, nucleosome positioning and open chromatin states. In addition, we show that the fundamental advance of MACE is the identification of two boundaries of a TFBS with high resolution, whereas other methods only report a single location of the same event. The two boundaries help elucidate the in vivo binding structure of a given TF, e.g. whether the TF may bind as dimers or in a complex with other co-factors. PMID:25249628

  1. A turbulent inflow model based on velocity modulation

    NASA Astrophysics Data System (ADS)

    Huyer, Stephen A.; Beal, David

    2007-11-01

    This article presents a novel turbulent inflow model based on modulation of the velocity field for use with time-domain propulsor calculations. Given an experimental mean and rms turbulent inflow, a model can be constructed by modulating the velocity field over a range of frequencies. Assuming the turbulence is homogeneous, the inflow can be constructed as a Fourier series where the frequencies can also be modulated to smooth the broadband output. To demonstrate the effectiveness of the model, experimental inflow velocity data were acquired for an upstream stator, downstream rotor configuration mounted on an undersea vehicle afterbody. Two main sources of turbulence originated from the vorticity shed from the stator wakes and the boundary layer vorticity produced on the hull body. Three-dimensional, unsteady velocity data were acquired using hot-wire anemometry and reduced to provide mean and rms velocity values. Time-series data were processed to provide velocity power spectra used to calibrate the model. Simulations were performed using a modified version of the propulsor unsteady flow code capable of computing fully turbulent inflows. This solver models the propulsor blade as a vortex lattice and sheds the vorticity into the wake to solve the unsteady potential flow. The no-flux boundary conditions are satisfied at the lattice control points and the resulting unsteady circulation is a function of the instantaneous inflow velocity field over the blade. Vorticity is shed into the wake to account for the full time history of the inflow velocity field. To demonstrate the full effectiveness of the model, computed surface pressure data were exported to a code to compute the far-field radiated noise (both tonal and broadband). Simulated data were compared with experimentally obtained noise data with favorable results. Applications of this methodology in the incompressible flow domain include broadband analysis of propulsor-radiated noise on undersea vehicles and

  2. Model-based adhesive shrinkage compensation for increased bonding repeatability

    NASA Astrophysics Data System (ADS)

    Müller, Tobias; Schlette, Christian; Lakshmanan, Shunmuganathan; Haag, Sebastian; Zontar, Daniel; Sauer, Sebastian; Wenzel, Christian; Brecher, Christian; Roβmann, Jürgen

    2016-03-01

    The assembly process of optical components consists of two phases - the alignment and the bonding phase. Precision - or better process repeatability - is limited by the latter one. The limitation of the alignment precision is given by the measurement equipment and the manipulation technology applied. Today's micromanipulators in combination with beam imaging setups allow for an alignment in the range of far below 100nm. However, once precisely aligned optics need to be fixed in their position. State o f the art in optics bonding for laser systems is adhesive bonding with UV-curing adhesives. Adhesive bonding is a multi-factorial process and thus subject to statistical process deviations. As a matter of fact, UV-curing adhesives inherit shrinkage effects during their curing process, making offsets for shrinkage compensation mandatory. Enhancing the process control of the adhesive bonding process is the major goal of the activities described in this paper. To improve the precision of shrinkage compensation a dynamic shrinkage prediction is envisioned by Fraunhofer IPT. Intense research activities are being practiced to gather a deeper understanding of the parameters influencing adhesive shrinkage behavior. These effects are of different nature - obviously being the raw adhesive material itself as well as its condition, the bonding geometry, environmental parameters like surrounding temperature and of course process parameters such as curing properties. Understanding the major parameters and linking them in a model-based shrinkage-prediction environment is the basis for improved process control. Results are being deployed by Fraunhofer in prototyping, as well as volume production solutions for laser systems.

  3. Rasch model based analysis of the Force Concept Inventory

    NASA Astrophysics Data System (ADS)

    Planinic, Maja; Ivanjek, Lana; Susac, Ana

    2010-06-01

    The Force Concept Inventory (FCI) is an important diagnostic instrument which is widely used in the field of physics education research. It is therefore very important to evaluate and monitor its functioning using different tools for statistical analysis. One of such tools is the stochastic Rasch model, which enables construction of linear measures for persons and items from raw test scores and which can provide important insight in the structure and functioning of the test (how item difficulties are distributed within the test, how well the items fit the model, and how well the items work together to define the underlying construct). The data for the Rasch analysis come from the large-scale research conducted in 2006-07, which investigated Croatian high school students’ conceptual understanding of mechanics on a representative sample of 1676 students (age 17-18 years). The instrument used in research was the FCI. The average FCI score for the whole sample was found to be (27.7±0.4)% , indicating that most of the students were still non-Newtonians at the end of high school, despite the fact that physics is a compulsory subject in Croatian schools. The large set of obtained data was analyzed with the Rasch measurement computer software WINSTEPS 3.66. Since the FCI is routinely used as pretest and post-test on two very different types of population (non-Newtonian and predominantly Newtonian), an additional predominantly Newtonian sample ( N=141 , average FCI score of 64.5%) of first year students enrolled in introductory physics course at University of Zagreb was also analyzed. The Rasch model based analysis suggests that the FCI has succeeded in defining a sufficiently unidimensional construct for each population. The analysis of fit of data to the model found no grossly misfitting items which would degrade measurement. Some items with larger misfit and items with significantly different difficulties in the two samples of students do require further examination

  4. Model-based HSF using by target point control function

    NASA Astrophysics Data System (ADS)

    Kim, Seongjin; Do, Munhoe; An, Yongbae; Choi, Jaeseung; Yang, Hyunjo; Yim, Donggyu

    2015-03-01

    As the technology node shrinks, ArF Immersion reaches the limitation of wafer patterning, furthermore weak point during the mask processing is generated easily. In order to make strong patterning result, the design house conducts lithography rule checking (LRC). Despite LRC processing, we found the weak point at the verification stage of optical proximity correction (OPC). It is called the hot spot point (HSP). In order to fix the HSP, many studies have been performed. One of the most general hot spot fixing (HSF) methods is that the modification bias which consists of "Line-Resizing" and "Space-Resizing". In addition to the general rule biasing method, resolution enhancement techniques (RET) which includes the inverse lithography technology (ILT) and model based assist feature (MBAF) have been adapted to remove the hot spot and to maximize the process window. If HSP is found during OPC verification stage, various HSF methods can be applied. However, HSF process added on regular OPC procedure makes OPC turn-around time (TAT) increased. In this paper, we introduce a new HSF method that is able to make OPC TAT shorter than the common HSF method. The new HSF method consists of two concepts. The first one is that OPC target point is controlled to fix HSP. Here, the target point should be moved to optimum position at where the edge placement error (EPE) can be 0 at critical points. Many parameters such as a model accuracy or an OPC recipe become the cause of larger EPE. The second one includes controlling of model offset error through target point adjustment. Figure 1 shows the case EPE is not 0. It means that the simulation contour was not targeted well after OPC process. On the other hand, Figure 2 shows the target point is moved -2.5nm by using target point control function. As a result, simulation contour is matched to the original layout. This function can be powerfully adapted to OPC procedure of memory and logic devices.

  5. Validation of model based active control of combustion instability

    SciTech Connect

    Fleifil, M.; Ghoneim, Z.; Ghoniem, A.F.

    1998-07-01

    The demand for efficient, company and clean combustion systems have spurred research into the fundamental mechanisms governing their performance and means of interactively changing their performance characteristics. Thermoacoustic instability which is frequently observed in combustion systems with high power density, when burning close to the lean flammability limit, or using exhaust gas recirculation to meet more stringent emissions regulations, etc. Its occurrence and/or means to mitigate them passively lead to performance degradation such as reduced combustion efficiency, high local heat transfer rates, increase in the mixture equivalence ratio or system failure due to structural damage. This paper reports on their study of the origin of thermoacoustic instability, its dependence on system parameters and the means of actively controlling it. The authors have developed an analytical model of thermoacoustic instability in premixed combustors. The model combines a heat release dynamics model constructed using the kinematics of a premixed flame stabilized behind a perforated plate with the linearized conservation equations governing the system acoustics. This formulation allows model based controller design. In order to test the performance of the analytical model, a numerical solution of the partial differential equations governing the system has been carried out using the principle of harmonic separation and focusing on the dominant unstable mode. This leads to a system of ODEs governing the thermofluid variables. Analytical predictions of the frequency and growth ate of the unstable mode are shown to be in good agreement with the numerical simulations as well s with those obtained using experimental identification techniques when applied to a laboratory combustor. The authors use these results to confirm the validity of the assumptions used in formulating the analytical model. A controller based on the minimization of a cost function using the LQR technique has

  6. Using hydroacoustic stations as water column seismometers

    NASA Astrophysics Data System (ADS)

    Yildiz, Selda; Sabra, Karim; Dorman, Leroy M.; Kuperman, W. A.

    2013-06-01

    Getting seismic data from the deep oceans usually involves ocean-bottom seismometers, but hydrophone arrays may provide a practical alternative means of obtaining vector data. We here explore this possibility using hydrophone stations of the International Monitoring System, which have been used to study icebergs and T-wave propagation among others. These stations consist of three hydrophones at about the depth of the deep sound channel in a horizontal triangle array with 2 km sides. We use data from these stations in the very low-frequency regime (0.01-0.05 Hz band) to demonstrate that these stations can also be used as water column seismometers. By differencing the acoustic pressure, we obtain vector quantities analogous to what a seismometer would record. Comparing processed hydrophone station records of the 2004 Great Sumatra-Andaman Earthquake with broadband seismograms from a nearby island station, we find that the differenced hydrophones are indeed a practical surrogate for seismometers.

  7. Hydroacoustic forcing function modeling using DNS database

    NASA Technical Reports Server (NTRS)

    Zawadzki, I.; Gershfield, J. L.; Na, Y.; Wang, M.

    1996-01-01

    A wall pressure frequency spectrum model (Blake 1971 ) has been evaluated using databases from Direct Numerical Simulations (DNS) of a turbulent boundary layer (Na & Moin 1996). Good agreement is found for moderate to strong adverse pressure gradient flows in the absence of separation. In the separated flow region, the model underpredicts the directly calculated spectra by an order of magnitude. The discrepancy is attributed to the violation of the model assumptions in that part of the flow domain. DNS computed coherence length scales and the normalized wall pressure cross-spectra are compared with experimental data. The DNS results are consistent with experimental observations.

  8. Models based on "out-of Kilter" algorithm

    NASA Astrophysics Data System (ADS)

    Adler, M. J.; Drobot, R.

    2012-04-01

    In case of many water users along the river stretches, it is very important, in case of low flows and droughty periods to develop an optimization model for water allocation, to cover all needs under certain predefined constraints, depending of the Contingency Plan for drought management. Such a program was developed during the implementation of the WATMAN Project, in Romania (WATMAN Project, 2005-2006, USTDA) for Arges-Dambovita-Ialomita Basins water transfers. This good practice was proposed for WATER CoRe Project- Good Practice Handbook for Drought Management, (InterregIVC, 2011), to be applied for the European Regions. Two types of simulation-optimization models based on an improved version of out-of-kilter algorithm as optimization technique have been developed and used in Romania: • models for founding of the short-term operation of a WMS, • models generically named SIMOPT that aim to the analysis of long-term WMS operation and have as the main results the statistical WMS functional parameters. A real WMS is modeled by an arcs-nodes network so the real WMS operation problem becomes a problem of flows in networks. The nodes and oriented arcs as well as their characteristics such as lower and upper limits and associated costs are the direct analog of the physical and operational WMS characteristics. Arcs represent both physical and conventional elements of WMS such as river branches, channels or pipes, water user demands or other water management requirements, trenches of water reservoirs volumes, water levels in channels or rivers, nodes are junctions of at least two arcs and stand for locations of lakes or water reservoirs and/or confluences of river branches, water withdrawal or wastewater discharge points, etc. Quantitative features of water resources, water users and water reservoirs or other water works are expressed as constraints of non-violating the lower and upper limits assigned on arcs. Options of WMS functioning i.e. water retention/discharge in

  9. Using Model-Based Reasoning for Autonomous Instrument Operation

    NASA Technical Reports Server (NTRS)

    Johnson, Mike; Rilee, M.; Truszkowski, W.; Powers, Edward I. (Technical Monitor)

    2000-01-01

    of environmental hazards, frame the problem of constructing autonomous science instruments. we are developing a model of the Low Energy Neutral Atom instrument (LENA) that is currently flying on board the Imager for Magnetosphere-to-Aurora Global Exploration (IMAGE) spacecraft. LENA is a particle detector that uses high voltage electrostatic optics and time-of-flight mass spectrometry to image neutral atom emissions from the denser regions of the Earth's magnetosphere. As with most spacecraft borne science instruments, phenomena in addition to neutral atoms are detected by LENA. Solar radiation and energetic particles from Earth's radiation belts are of particular concern because they may help generate currents that may compromise LENA's long term performance. An explicit model of the instrument response has been constructed and is currently in use on board IMAGE to dynamically adapt LENA to the presence or absence of energetic background radiations. The components of LENA are common in space science instrumentation, and lessons learned by modelling this system may be applied to other instruments. This work demonstrates that a model-based approach can be used to enhance science instrument effectiveness. Our future work involves the extension of these methods to cover more aspects of LENA operation and the generalization to other space science instrumentation.

  10. Sequential Model-Based Detection in a Shallow Ocean Acoustic Environment

    SciTech Connect

    Candy, J V

    2002-03-26

    A model-based detection scheme is developed to passively monitor an ocean acoustic environment along with its associated variations. The technique employs an embedded model-based processor and a reference model in a sequential likelihood detection scheme. The monitor is therefore called a sequential reference detector. The underlying theory for the design is developed and discussed in detail.

  11. Cycles of Exploration, Reflection, and Consolidation in Model-Based Learning of Genetics

    ERIC Educational Resources Information Center

    Kim, Beaumie; Pathak, Suneeta A.; Jacobson, Michael J.; Zhang, Baohui; Gobert, Janice D.

    2015-01-01

    Model-based reasoning has been introduced as an authentic way of learning science, and many researchers have developed technological tools for learning with models. This paper describes how a model-based tool, "BioLogica"™, was used to facilitate genetics learning in secondary 3-level biology in Singapore. The research team co-designed…

  12. The Use of Modeling-Based Text to Improve Students' Modeling Competencies

    ERIC Educational Resources Information Center

    Jong, Jing-Ping; Chiu, Mei-Hung; Chung, Shiao-Lan

    2015-01-01

    This study investigated the effects of a modeling-based text on 10th graders' modeling competencies. Fifteen 10th graders read a researcher-developed modeling-based science text on the ideal gas law that included explicit descriptions and representations of modeling processes (i.e., model selection, model construction, model validation, model…

  13. Model-based task planning system for a space laboratory environment

    NASA Technical Reports Server (NTRS)

    Chi, Sung-Do; Zeigler, Bernard P.; Cellier, Francois

    1991-01-01

    This paper describes the design of a model-based autonomous planning system that will enable robots to manage a space-borne chemical laboratory. In a model-based planning system, knowledge is encapsulated in the form of models at the various layers to support the predefined system objectives. Thus the model-based approach can be considered as an extended planning paradigm which is able to base its planning, control, diagnosis, repair, and other activities on a variety of objectives-related models. A System Entity Structure/Model Base framework is employed to support autonomous system design through the ability to generate a family of planning alternatives as well as to build hierarchical event-based control structures. The model base is a multilevel, multiabstraction, and multiformalism system organized through the use of system morphisms to integrate related models.

  14. In defense of compilation: A response to Davis' form and content in model-based reasoning

    NASA Technical Reports Server (NTRS)

    Keller, Richard

    1990-01-01

    In a recent paper entitled 'Form and Content in Model Based Reasoning', Randy Davis argues that model based reasoning research aimed at compiling task specific rules from underlying device models is mislabeled, misguided, and diversionary. Some of Davis' claims are examined and his basic conclusions are challenged about the value of compilation research to the model based reasoning community. In particular, Davis' claim is refuted that model based reasoning is exempt from the efficiency benefits provided by knowledge compilation techniques. In addition, several misconceptions are clarified about the role of representational form in compilation. It is concluded that techniques have the potential to make a substantial contribution to solving tractability problems in model based reasoning.

  15. Practical Application of Model-based Programming and State-based Architecture to Space Missions

    NASA Technical Reports Server (NTRS)

    Horvath, Gregory; Ingham, Michel; Chung, Seung; Martin, Oliver; Williams, Brian

    2006-01-01

    A viewgraph presentation to develop models from systems engineers that accomplish mission objectives and manage the health of the system is shown. The topics include: 1) Overview; 2) Motivation; 3) Objective/Vision; 4) Approach; 5) Background: The Mission Data System; 6) Background: State-based Control Architecture System; 7) Background: State Analysis; 8) Overview of State Analysis; 9) Background: MDS Software Frameworks; 10) Background: Model-based Programming; 10) Background: Titan Model-based Executive; 11) Model-based Execution Architecture; 12) Compatibility Analysis of MDS and Titan Architectures; 13) Integrating Model-based Programming and Execution into the Architecture; 14) State Analysis and Modeling; 15) IMU Subsystem State Effects Diagram; 16) Titan Subsystem Model: IMU Health; 17) Integrating Model-based Programming and Execution into the Software IMU; 18) Testing Program; 19) Computationally Tractable State Estimation & Fault Diagnosis; 20) Diagnostic Algorithm Performance; 21) Integration and Test Issues; 22) Demonstrated Benefits; and 23) Next Steps

  16. A method for diagnosing time dependent faults using model-based reasoning systems

    NASA Technical Reports Server (NTRS)

    Goodrich, Charles H.

    1995-01-01

    This paper explores techniques to apply model-based reasoning to equipment and systems which exhibit dynamic behavior (that which changes as a function of time). The model-based system of interest is KATE-C (Knowledge based Autonomous Test Engineer) which is a C++ based system designed to perform monitoring and diagnosis of Space Shuttle electro-mechanical systems. Methods of model-based monitoring and diagnosis are well known and have been thoroughly explored by others. A short example is given which illustrates the principle of model-based reasoning and reveals some limitations of static, non-time-dependent simulation. This example is then extended to demonstrate representation of time-dependent behavior and testing of fault hypotheses in that environment.

  17. Model-based Clustering of High-Dimensional Data in Astrophysics

    NASA Astrophysics Data System (ADS)

    Bouveyron, C.

    2016-05-01

    The nature of data in Astrophysics has changed, as in other scientific fields, in the past decades due to the increase of the measurement capabilities. As a consequence, data are nowadays frequently of high dimensionality and available in mass or stream. Model-based techniques for clustering are popular tools which are renowned for their probabilistic foundations and their flexibility. However, classical model-based techniques show a disappointing behavior in high-dimensional spaces which is mainly due to their dramatical over-parametrization. The recent developments in model-based classification overcome these drawbacks and allow to efficiently classify high-dimensional data, even in the "small n / large p" situation. This work presents a comprehensive review of these recent approaches, including regularization-based techniques, parsimonious modeling, subspace classification methods and classification methods based on variable selection. The use of these model-based methods is also illustrated on real-world classification problems in Astrophysics using R packages.

  18. Role of Imaging Specrometer Data for Model-based Cross-calibration of Imaging Sensors

    NASA Technical Reports Server (NTRS)

    Thome, Kurtis John

    2014-01-01

    Site characterization benefits from imaging spectrometry to determine spectral bi-directional reflectance of a well-understood surface. Cross calibration approaches, uncertainties, role of imaging spectrometry, model-based site characterization, and application to product validation.

  19. Model-based failure detection for cylindrical shells from noisy vibration measurements.

    PubMed

    Candy, J V; Fisher, K A; Guidry, B L; Chambers, D H

    2014-12-01

    Model-based processing is a theoretically sound methodology to address difficult objectives in complex physical problems involving multi-channel sensor measurement systems. It involves the incorporation of analytical models of both physical phenomenology (complex vibrating structures, noisy operating environment, etc.) and the measurement processes (sensor networks and including noise) into the processor to extract the desired information. In this paper, a model-based methodology is developed to accomplish the task of online failure monitoring of a vibrating cylindrical shell externally excited by controlled excitations. A model-based processor is formulated to monitor system performance and detect potential failure conditions. The objective of this paper is to develop a real-time, model-based monitoring scheme for online diagnostics in a representative structural vibrational system based on controlled experimental data. PMID:25480059

  20. Monitoring the Ocean Acoustic Environment: A Model-Based Detection Approach

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    2000-03-13

    A model-based approach is applied in the development of a processor designed to passively monitor an ocean acoustic environment along with its associated variations. The technique employs an adaptive, model-based processor embedded in a sequential likelihood detection scheme. The trade-off between state-based and innovations-based monitor designs is discussed, conceptually. The underlying theory for the innovations-based design is briefly developed and applied to a simulated data set.

  1. Characterization of multiple SPS knockout mutants reveals redundant functions of the four Arabidopsis sucrose phosphate synthase isoforms in plant viability, and strongly indicates that enhanced respiration and accelerated starch turnover can alleviate the blockage of sucrose biosynthesis.

    PubMed

    Bahaji, Abdellatif; Baroja-Fernández, Edurne; Ricarte-Bermejo, Adriana; Sánchez-López, Ángela María; Muñoz, Francisco José; Romero, Jose M; Ruiz, María Teresa; Baslam, Marouane; Almagro, Goizeder; Sesma, María Teresa; Pozueta-Romero, Javier

    2015-09-01

    We characterized multiple knock-out mutants of the four Arabidopsis sucrose phosphate synthase (SPSA1, SPSA2, SPSB and SPSC) isoforms. Despite their reduced SPS activity, spsa1/spsa2, spsa1/spsb, spsa2/spsb, spsa2/spsc, spsb/spsc, spsa1/spsa2/spsb and spsa2/spsb/spsc mutants displayed wild type (WT) vegetative and reproductive morphology, and showed WT photosynthetic capacity and respiration. In contrast, growth of rosettes, flowers and siliques of the spsa1/spsc and spsa1/spsa2/spsc mutants was reduced compared with WT plants. Furthermore, these plants displayed a high dark respiration phenotype. spsa1/spsb/spsc and spsa1/spsa2/spsb/spsc seeds poorly germinated and produced aberrant and sterile plants. Leaves of all viable sps mutants, except spsa1/spsc and spsa1/spsa2/spsc, accumulated WT levels of nonstructural carbohydrates. spsa1/spsc leaves possessed high levels of metabolic intermediates and activities of enzymes of the glycolytic and tricarboxylic acid cycle pathways, and accumulated high levels of metabolic intermediates of the nocturnal starch-to-sucrose conversion process, even under continuous light conditions. Results presented in this work show that SPS is essential for plant viability, reveal redundant functions of the four SPS isoforms in processes that are important for plant growth and nonstructural carbohydrate metabolism, and strongly indicate that accelerated starch turnover and enhanced respiration can alleviate the blockage of sucrose biosynthesis in spsa1/spsc leaves. PMID:26259182

  2. The interaction of acute and chronic stress impairs model-based behavioral control.

    PubMed

    Radenbach, Christoph; Reiter, Andrea M F; Engert, Veronika; Sjoerds, Zsuzsika; Villringer, Arno; Heinze, Hans-Jochen; Deserno, Lorenz; Schlagenhauf, Florian

    2015-03-01

    It is suggested that acute stress shifts behavioral control from goal-directed, model-based toward habitual, model-free strategies. Recent findings indicate that interindividual differences in the cortisol stress response influence model-based decision-making. Although not yet investigated in humans, animal studies show that chronic stress also shifts decision-making toward more habitual behavior. Here, we ask whether acute stress and individual vulnerability factors, such as stress reactivity and previous exposure to stressful life events, impact the balance between model-free and model-based control systems. To test this, 39 male participants (21-30 years old) were exposed to a potent psychosocial stressor (Trier Social Stress Test) and a control condition in a within-subjects design before they performed a sequential decision-making task which evaluates the balance between the two systems. Physiological and subjective stress reactivity was assessed before, during, and after acute stress exposure. By means of computational modeling, we demonstrate that interindividual variability in stress reactivity predicts impairments in model-based decision-making. Whereas acute psychosocial stress did not alter model-based behavioral control, we found chronic and acute stress to interact in their detrimental effect on decision-making: subjects with high but not low chronic stress levels as indicated by stressful life events exhibited reduced model-based control in response to acute psychosocial stress. These findings emphasize that stress reactivity and chronic stress play an important role in mediating the relationship between stress and decision-making. Our results might stimulate new insights into the interplay between chronic and acute stress, attenuated model-based control, and the pathogenesis of various psychiatric diseases. PMID:25662093

  3. A model-based approach to reactive self-configuring systems

    SciTech Connect

    Williams, B.C.; Nayak, P.P.

    1996-12-31

    This paper describes Livingstone, an implemented kernel for a model-based reactive self-configuring autonomous system. It presents a formal characterization of Livingstone`s representation formalism, and reports on our experience with the implementation in a variety of domains. Livingstone provides a reactive system that performs significant deduction in the sense/response loop by drawing on our past experience at building fast propositional conflict-based algorithms for model-based diagnosis, and by framing a model-based configuration manager as a propositional feedback controller that generates focused, optimal responses. Livingstone`s representation formalism achieves broad coverage of hybrid hardware/software systems by coupling the transition system models underlying concurrent reactive languages with the qualitative representations developed in model-based reasoning. Livingstone automates a wide variety of tasks using a single model and a single core algorithm, thus making significant progress towards achieving a central goal of model-based reasoning. Livingstone, together with the HSTS planning and scheduling engine and the RAPS executive, has been selected as part of the core autonomy architecture for NASA`s first New Millennium spacecraft.

  4. The application criterion of model-based optical proximity correction in a low k1 process

    NASA Astrophysics Data System (ADS)

    Lee, Doo-Youl; Kim, In-Sung; Jung, Sung-Gon; Jung, Myoung-Ho; Park, Joo-On; Oh, Seok-Hwan; Woo, Sang-Gyun; Cho, Han-Ku; Moon, Joo-Tae

    2005-05-01

    As k1 factor approaches the theoretical limit, optical proximity correction (OPC) treatments necessary to maintain dimensional tolerances involve increasingly complex correction shapes. This translates to more detailed, or larger mask pattern databases. Moreover, development of exposure tools lags behind the shrinkage of device. This may result in dwindling of process margin in lighographic process despite using all possible resolution enhancement techniques (RETs). Although model-based OPC may lose its effectiveness in case of narrower photolithographic process margin, model-based OPC is recognized as a robust tool to cope with the diversity of layout. By the way, in case of narrower photolithographic process margin, model-based OPC lose its effectiveness. To enhance the usefulness of the OPC, we need to overcome many obstacles. It is supposed that the original layout be designed friendly to lithography to enhance the process margin using aggressive RETs, and is amended by model-based OPC to suppress the proximity effect. But, some constraints are found during an OPC procedure. Ultimately, unless the original lithgraphy friendly layout (LFL) is corrected in terms of pitches and shapes, the lithography process is out of process window as well as makes pattern fidelity poor. This paper emphasizes that the application of model-based OPC requires a particular and unique layout configuration to preserve the process margin in the low k1 process.

  5. Gaze data reveal distinct choice processes underlying model-based and model-free reinforcement learning

    PubMed Central

    Konovalov, Arkady; Krajbich, Ian

    2016-01-01

    Organisms appear to learn and make decisions using different strategies known as model-free and model-based learning; the former is mere reinforcement of previously rewarded actions and the latter is a forward-looking strategy that involves evaluation of action-state transition probabilities. Prior work has used neural data to argue that both model-based and model-free learners implement a value comparison process at trial onset, but model-based learners assign more weight to forward-looking computations. Here using eye-tracking, we report evidence for a different interpretation of prior results: model-based subjects make their choices prior to trial onset. In contrast, model-free subjects tend to ignore model-based aspects of the task and instead seem to treat the decision problem as a simple comparison process between two differentially valued items, consistent with previous work on sequential-sampling models of decision making. These findings illustrate a problem with assuming that experimental subjects make their decisions at the same prescribed time. PMID:27511383

  6. Gaze data reveal distinct choice processes underlying model-based and model-free reinforcement learning.

    PubMed

    Konovalov, Arkady; Krajbich, Ian

    2016-01-01

    Organisms appear to learn and make decisions using different strategies known as model-free and model-based learning; the former is mere reinforcement of previously rewarded actions and the latter is a forward-looking strategy that involves evaluation of action-state transition probabilities. Prior work has used neural data to argue that both model-based and model-free learners implement a value comparison process at trial onset, but model-based learners assign more weight to forward-looking computations. Here using eye-tracking, we report evidence for a different interpretation of prior results: model-based subjects make their choices prior to trial onset. In contrast, model-free subjects tend to ignore model-based aspects of the task and instead seem to treat the decision problem as a simple comparison process between two differentially valued items, consistent with previous work on sequential-sampling models of decision making. These findings illustrate a problem with assuming that experimental subjects make their decisions at the same prescribed time. PMID:27511383

  7. A Model-Based Expert System for Space Power Distribution Diagnostics

    NASA Technical Reports Server (NTRS)

    Quinn, Todd M.; Schlegelmilch, Richard F.

    1994-01-01

    When engineers diagnose system failures, they often use models to confirm system operation. This concept has produced a class of advanced expert systems that perform model-based diagnosis. A model-based diagnostic expert system for the Space Station Freedom electrical power distribution test bed is currently being developed at the NASA Lewis Research Center. The objective of this expert system is to autonomously detect and isolate electrical fault conditions. Marple, a software package developed at TRW, provides a model-based environment utilizing constraint suspension. Originally, constraint suspension techniques were developed for digital systems. However, Marple provides the mechanisms for applying this approach to analog systems such as the test bed, as well. The expert system was developed using Marple and Lucid Common Lisp running on a Sun Sparc-2 workstation. The Marple modeling environment has proved to be a useful tool for investigating the various aspects of model-based diagnostics. This report describes work completed to date and lessons learned while employing model-based diagnostics using constraint suspension within an analog system.

  8. Model-based adaptive 3D sonar reconstruction in reverberating environments.

    PubMed

    Saucan, Augustin-Alexandru; Sintes, Christophe; Chonavel, Thierry; Caillec, Jean-Marc Le

    2015-10-01

    In this paper, we propose a novel model-based approach for 3D underwater scene reconstruction, i.e., bathymetry, for side scan sonar arrays in complex and highly reverberating environments like shallow water areas. The presence of multipath echoes and volume reverberation generates false depth estimates. To improve the resulting bathymetry, this paper proposes and develops an adaptive filter, based on several original geometrical models. This multimodel approach makes it possible to track and separate the direction of arrival trajectories of multiple echoes impinging the array. Echo tracking is perceived as a model-based processing stage, incorporating prior information on the temporal evolution of echoes in order to reject cluttered observations generated by interfering echoes. The results of the proposed filter on simulated and real sonar data showcase the clutter-free and regularized bathymetric reconstruction. Model validation is carried out with goodness of fit tests, and demonstrates the importance of model-based processing for bathymetry reconstruction. PMID:25974936

  9. Focus on connections for successful organizational transformation to model based engineering

    NASA Astrophysics Data System (ADS)

    Babineau, Guy L.

    2015-05-01

    Organizational Transformation to a Model Based Engineering Culture is a significant goal for Northrop Grumman Electronic Systems in order to achieve objectives of increased engineering performance. While organizational change is difficult, a focus on connections is creating success. Connections include model to model, program phase to program phase and organization to organization all through Model Based techniques. This presentation will address the techniques employed by Northrop Grumman to achieve these results as well as address continued focus and efforts. Model to model connections are very effective in automating implicit linkages between models for the purpose of ensuring consistency across a set of models and also for rapidly assessing impact of change. Program phase to phase connections are very important for reducing development time as well as reducing potential errors in moving from one program phase to another. Organization to organization communication is greatly facilitated using model based techniques to eliminate ambiguity and drive consistency and reuse.

  10. Model-based monitoring and diagnosis of a satellite-based instrument

    NASA Technical Reports Server (NTRS)

    Bos, Andre; Callies, Jorg; Lefebvre, Alain

    1995-01-01

    For about a decade model-based reasoning has been propounded by a number of researchers. Maybe one of the most convincing arguments in favor of this kind of reasoning has been given by Davis in his paper on diagnosis from first principles (Davis 1984). Following their guidelines we have developed a system to verify the behavior of a satellite-based instrument GOME (which will be measuring Ozone concentrations in the near future (1995)). We start by giving a description of model-based monitoring. Besides recognizing that something is wrong, we also like to find the cause for misbehaving automatically. Therefore, we show how the monitoring technique can be extended to model-based diagnosis.

  11. Lateral prefrontal model-based signatures are reduced in healthy individuals with high trait impulsivity

    PubMed Central

    Deserno, L; Wilbertz, T; Reiter, A; Horstmann, A; Neumann, J; Villringer, A; Heinze, H-J; Schlagenhauf, F

    2015-01-01

    High impulsivity is an important risk factor for addiction with evidence from endophenotype studies. In addiction, behavioral control is shifted toward the habitual end. Habitual control can be described by retrospective updating of reward expectations in ‘model-free' temporal-difference algorithms. Goal-directed control relies on the prospective consideration of actions and their outcomes, which can be captured by forward-planning ‘model-based' algorithms. So far, no studies have examined behavioral and neural signatures of model-free and model-based control in healthy high-impulsive individuals. Fifty healthy participants were drawn from the upper and lower ends of 452 individuals, completing the Barratt Impulsiveness Scale. All participants performed a sequential decision-making task during functional magnetic resonance imaging (fMRI) and underwent structural MRI. Behavioral and fMRI data were analyzed by means of computational algorithms reflecting model-free and model-based control. Both groups did not differ regarding the balance of model-free and model-based control, but high-impulsive individuals showed a subtle but significant accentuation of model-free control alone. Right lateral prefrontal model-based signatures were reduced in high-impulsive individuals. Effects of smoking, drinking, general cognition or gray matter density did not account for the findings. Irrespectively of impulsivity, gray matter density in the left dorsolateral prefrontal cortex was positively associated with model-based control. The present study supports the idea that high levels of impulsivity are accompanied by behavioral and neural signatures in favor of model-free behavioral control. Behavioral results in healthy high-impulsive individuals were qualitatively different to findings in patients with the same task. The predictive relevance of these results remains an important target for future longitudinal studies. PMID:26460483

  12. Risk Factors for Addiction and Their Association with Model-Based Behavioral Control

    PubMed Central

    Reiter, Andrea M. F.; Deserno, Lorenz; Wilbertz, Tilmann; Heinze, Hans-Jochen; Schlagenhauf, Florian

    2016-01-01

    Addiction shows familial aggregation and previous endophenotype research suggests that healthy relatives of addicted individuals share altered behavioral and cognitive characteristics with individuals suffering from addiction. In this study we asked whether impairments in behavioral control proposed for addiction, namely a shift from goal-directed, model-based toward habitual, model-free control, extends toward an unaffected sample (n = 20) of adult children of alcohol-dependent fathers as compared to a sample without any personal or family history of alcohol addiction (n = 17). Using a sequential decision-making task designed to investigate model-free and model-based control combined with a computational modeling analysis, we did not find any evidence for altered behavioral control in individuals with a positive family history of alcohol addiction. Independent of family history of alcohol dependence, we however observed that the interaction of two different risk factors of addiction, namely impulsivity and cognitive capacities, predicts the balance of model-free and model-based behavioral control. Post-hoc tests showed a positive association of model-based behavior with cognitive capacity in the lower, but not in the higher impulsive group of the original sample. In an independent sample of particularly high- vs. low-impulsive individuals, we confirmed the interaction effect of cognitive capacities and high vs. low impulsivity on model-based control. In the confirmation sample, a positive association of omega with cognitive capacity was observed in highly impulsive individuals, but not in low impulsive individuals. Due to the moderate sample size of the study, further investigation of the association of risk factors for addiction with model-based behavior in larger sample sizes is warranted. PMID:27013998

  13. Risk Factors for Addiction and Their Association with Model-Based Behavioral Control.

    PubMed

    Reiter, Andrea M F; Deserno, Lorenz; Wilbertz, Tilmann; Heinze, Hans-Jochen; Schlagenhauf, Florian

    2016-01-01

    Addiction shows familial aggregation and previous endophenotype research suggests that healthy relatives of addicted individuals share altered behavioral and cognitive characteristics with individuals suffering from addiction. In this study we asked whether impairments in behavioral control proposed for addiction, namely a shift from goal-directed, model-based toward habitual, model-free control, extends toward an unaffected sample (n = 20) of adult children of alcohol-dependent fathers as compared to a sample without any personal or family history of alcohol addiction (n = 17). Using a sequential decision-making task designed to investigate model-free and model-based control combined with a computational modeling analysis, we did not find any evidence for altered behavioral control in individuals with a positive family history of alcohol addiction. Independent of family history of alcohol dependence, we however observed that the interaction of two different risk factors of addiction, namely impulsivity and cognitive capacities, predicts the balance of model-free and model-based behavioral control. Post-hoc tests showed a positive association of model-based behavior with cognitive capacity in the lower, but not in the higher impulsive group of the original sample. In an independent sample of particularly high- vs. low-impulsive individuals, we confirmed the interaction effect of cognitive capacities and high vs. low impulsivity on model-based control. In the confirmation sample, a positive association of omega with cognitive capacity was observed in highly impulsive individuals, but not in low impulsive individuals. Due to the moderate sample size of the study, further investigation of the association of risk factors for addiction with model-based behavior in larger sample sizes is warranted. PMID:27013998

  14. Lateral prefrontal model-based signatures are reduced in healthy individuals with high trait impulsivity.

    PubMed

    Deserno, L; Wilbertz, T; Reiter, A; Horstmann, A; Neumann, J; Villringer, A; Heinze, H-J; Schlagenhauf, F

    2015-01-01

    High impulsivity is an important risk factor for addiction with evidence from endophenotype studies. In addiction, behavioral control is shifted toward the habitual end. Habitual control can be described by retrospective updating of reward expectations in 'model-free' temporal-difference algorithms. Goal-directed control relies on the prospective consideration of actions and their outcomes, which can be captured by forward-planning 'model-based' algorithms. So far, no studies have examined behavioral and neural signatures of model-free and model-based control in healthy high-impulsive individuals. Fifty healthy participants were drawn from the upper and lower ends of 452 individuals, completing the Barratt Impulsiveness Scale. All participants performed a sequential decision-making task during functional magnetic resonance imaging (fMRI) and underwent structural MRI. Behavioral and fMRI data were analyzed by means of computational algorithms reflecting model-free and model-based control. Both groups did not differ regarding the balance of model-free and model-based control, but high-impulsive individuals showed a subtle but significant accentuation of model-free control alone. Right lateral prefrontal model-based signatures were reduced in high-impulsive individuals. Effects of smoking, drinking, general cognition or gray matter density did not account for the findings. Irrespectively of impulsivity, gray matter density in the left dorsolateral prefrontal cortex was positively associated with model-based control. The present study supports the idea that high levels of impulsivity are accompanied by behavioral and neural signatures in favor of model-free behavioral control. Behavioral results in healthy high-impulsive individuals were qualitatively different to findings in patients with the same task. The predictive relevance of these results remains an important target for future longitudinal studies. PMID:26460483

  15. Model based matching using simulated annealing and a minimum representation size criterion

    NASA Technical Reports Server (NTRS)

    Ravichandran, B.; Sanderson, A. C.

    1992-01-01

    We define the model based matching problem in terms of the correspondence and transformation that relate the model and scene, and the search and evaluation measures needed to find the best correspondence and transformation. Simulated annealing is proposed as a method for search and optimization, and the minimum representation size criterion is used as the evaluation measure in an algorithm that finds the best correspondence. An algorithm based on simulated annealing is presented and evaluated. This algorithm is viewed as a part of an adaptive, hierarchical approach which provides robust results for a variety of model based matching problems.

  16. Note: Model-based identification method of a cable-driven wearable device for arm rehabilitation

    NASA Astrophysics Data System (ADS)

    Cui, Xiang; Chen, Weihai; Zhang, Jianbin; Wang, Jianhua

    2015-09-01

    Cable-driven exoskeletons have used active cables to actuate the system and are worn on subjects to provide motion assistance. However, this kind of wearable devices usually contains uncertain kinematic parameters. In this paper, a model-based identification method has been proposed for a cable-driven arm exoskeleton to estimate its uncertainties. The identification method is based on the linearized error model derived from the kinematics of the exoskeleton. Experiment has been conducted to demonstrate the feasibility of the proposed model-based method in practical application.

  17. Development of model-based multispectral controllers for smart material systems

    NASA Astrophysics Data System (ADS)

    Kim, Byeongil; Washington, Gregory N.

    2009-03-01

    The primary objective of this research is to develop novel model-based multispectral controllers for smart material systems in order to deal with sidebands and higher harmonics and with several frequency components simultaneously. Based on the filtered-X least mean square algorithm, it will be integrated with a nonlinear model-based controller called model predictive sliding mode control. Their performance will be verified in simulation and with various applications such as helicopter cabin noise reduction. This research will improve active vibration and noise control systems used in engineering structures and vehicles by effectively dealing with a wide range of multispectral signals.

  18. Livingstone Model-Based Diagnosis of Earth Observing One Infusion Experiment

    NASA Technical Reports Server (NTRS)

    Hayden, Sandra C.; Sweet, Adam J.; Christa, Scott E.

    2004-01-01

    The Earth Observing One satellite, launched in November 2000, is an active earth science observation platform. This paper reports on the progress of an infusion experiment in which the Livingstone 2 Model-Based Diagnostic engine is deployed on Earth Observing One, demonstrating the capability to monitor the nominal operation of the spacecraft under command of an on-board planner, and demonstrating on-board diagnosis of spacecraft failures. Design and development of the experiment, specification and validation of diagnostic scenarios, characterization of performance results and benefits of the model- based approach are presented.

  19. Improved shape-signature and matching methods for model-based robotic vision

    NASA Technical Reports Server (NTRS)

    Schwartz, J. T.; Wolfson, H. J.

    1987-01-01

    Researchers describe new techniques for curve matching and model-based object recognition, which are based on the notion of shape-signature. The signature which researchers use is an approximation of pointwise curvature. Described here is curve matching algorithm which generalizes a previous algorithm which was developed using this signature, allowing improvement and generalization of a previous model-based object recognition scheme. The results and the experiments described relate to 2-D images. However, natural extensions to the 3-D case exist and are being developed.

  20. Implementation of a Fractional Model-Based Fault Detection Algorithm into a PLC Controller

    NASA Astrophysics Data System (ADS)

    Kopka, Ryszard

    2014-12-01

    This paper presents results related to the implementation of model-based fault detection and diagnosis procedures into a typical PLC controller. To construct the mathematical model and to implement the PID regulator, a non-integer order differential/integral calculation was used. Such an approach allows for more exact control of the process and more precise modelling. This is very crucial in model-based diagnostic methods. The theoretical results were verified on a real object in the form of a supercapacitor connected to a PLC controller by a dedicated electronic circuit controlled directly from the PLC outputs.

  1. Improved Model-Based Polarimetric Decomposition Using the POlINSAR Similarity Parameter

    NASA Astrophysics Data System (ADS)

    Latrache, H.; Ouarzeddine, M.; Souissi, B.

    2016-06-01

    In this paper, we present a new approach to solve the problem of volume scattering ambiguity in urban area, for that we propose a volume model based on the polarimetric interferometric similarity parameter (PISP) . The new model is more adaptive and fits better with both forest and oriented built-up areas. Thereby, a new model-based polarimetric decomposition scheme is developed. To test the performance of the proposed method ESAR PolInSAR L bande data of Oberpfaffenhofen, Germany is used. Comparison experiments show that the proposed method gives good results, since all the oriented built-up areas are well discriminated as double or odd bounce structures.

  2. Improving model-based diagnosis through algebraic analysis: The Petri net challenge

    SciTech Connect

    Portinale, L.

    1996-12-31

    The present paper describes the empirical evaluation of a linear algebra approach to model-based diagnosis, in case the behavioral model of the device under examination is described through a Petri net model. In particular, we show that algebraic analysis based on P-invariants of the net model, can significantly improve the performance of a model-based diagnostic system, while keeping the integrity of a general framework defined from a formal logical theory. A system called INVADS is described and experimental results, performed on a car fault domain and involving the comparison of different implementations of P-invariant based diagnosis, are then discussed.

  3. Model-Based Reasoning in the Physics Laboratory: Framework and Initial Results

    ERIC Educational Resources Information Center

    Zwickl, Benjamin M.; Hu, Dehui; Finkelstein, Noah; Lewandowski, H. J.

    2015-01-01

    We review and extend existing frameworks on modeling to develop a new framework that describes model-based reasoning in introductory and upper-division physics laboratories. Constructing and using models are core scientific practices that have gained significant attention within K-12 and higher education. Although modeling is a broadly applicable…

  4. A Model-based Approach to Reactive Self-Configuring Systems

    NASA Technical Reports Server (NTRS)

    Williams, Brian C.; Nayak, P. Pandurang

    1996-01-01

    This paper describes Livingstone, an implemented kernel for a self-reconfiguring autonomous system, that is reactive and uses component-based declarative models. The paper presents a formal characterization of the representation formalism used in Livingstone, and reports on our experience with the implementation in a variety of domains. Livingstone's representation formalism achieves broad coverage of hybrid software/hardware systems by coupling the concurrent transition system models underlying concurrent reactive languages with the discrete qualitative representations developed in model-based reasoning. We achieve a reactive system that performs significant deductions in the sense/response loop by drawing on our past experience at building fast prepositional conflict-based algorithms for model-based diagnosis, and by framing a model-based configuration manager as a prepositional, conflict-based feedback controller that generates focused, optimal responses. Livingstone automates all these tasks using a single model and a single core deductive engine, thus making significant progress towards achieving a central goal of model-based reasoning. Livingstone, together with the HSTS planning and scheduling engine and the RAPS executive, has been selected as the core autonomy architecture for Deep Space One, the first spacecraft for NASA's New Millennium program.

  5. Measuring Model-Based High School Science Instruction: Development and Application of a Student Survey

    ERIC Educational Resources Information Center

    Fulmer, Gavin W.; Liang, Ling L.

    2013-01-01

    This study tested a student survey to detect differences in instruction between teachers in a modeling-based science program and comparison group teachers. The Instructional Activities Survey measured teachers' frequency of modeling, inquiry, and lecture instruction. Factor analysis and Rasch modeling identified three subscales, Modeling and…

  6. Chapter 6: Implementation of Model-Based Instruction--The Induction Years

    ERIC Educational Resources Information Center

    Gurvitch, Rachel; Blankenship, Bonnie Tjeerdsma

    2008-01-01

    In previous chapters, student teachers' views and the use of model-based instruction (MBI) were determined to be largely positive. But do these positive attitudes and the actual use of MBI continue after completing a teacher education program? Many novice teachers experience "washout" when the attitudes and instructional practices they acquired…

  7. Discursive Modes and Their Pedagogical Functions in Model-Based Inquiry (MBI) Classrooms

    ERIC Educational Resources Information Center

    Campbell, Todd; Oh, Phil Seok; Neilson, Drew

    2012-01-01

    This research investigated the emergent discursive modes and their pedagogical functions found in model-based inquiry (MBI) science classrooms. A sample of four high school physics classrooms was video-recorded and analysed using a newly established discourse mode analysis framework. Qualitative methods were employed to identify the most salient…

  8. Chapter 8: The Diffusion of Model-Based Instruction by Establishing Communities of Practice

    ERIC Educational Resources Information Center

    Metzler, Michael W.; Lund, Jacalyn L.; Gurvitch, Rachel

    2008-01-01

    Previous chapters in this monograph have reported on a series of research studies that examined the adoption of an instructional innovation, model-based instruction (MBI), by teachers in three stages of career development: preservice/student teachers (STs), induction teachers (ITs), and experienced/cooperating teachers (CTs). All the teachers were…

  9. Chapter 7: Influences on Cooperating Teachers' Adoption of Model-Based Instruction

    ERIC Educational Resources Information Center

    Lund, Jacalyn L.; Gurvitch, Rachel; Metzler, Michael W.

    2008-01-01

    This article considers another group of educators involved with the adoption of model-based instruction (MBI)--the cooperating teachers, who supervise physical education teacher education (PETE) student teachers in the Georgia State University (GSU) program. The university spends several semesters educating preservice teachers about the skills and…

  10. Model Based Inquiry in the High School Physics Classroom: An Exploratory Study of Implementation and Outcomes

    ERIC Educational Resources Information Center

    Campbell, Todd; Zhang, Danhui; Neilson, Drew

    2011-01-01

    This study considers whether Model Based Inquiry (MBI) is a suitable mechanism for facilitating science as inquiry to allow students to develop deep understandings of difficult concepts, while also gaining better understandings of science process and the nature of science. This manuscript also considers time devoted to MBI in comparison to more…

  11. Model-Based Instruction: Theory and Application in a Teacher Education Program.

    ERIC Educational Resources Information Center

    Steinley, Gary; Reisetter, Marcy; Penrod, Kathryn; Haar, Jean; Ellingson, Janna

    Model-Based Instruction (MBI) plays a significant role in the undergraduate teacher education program at South Dakota State University. Integrated into the program 8 years ago, the understandings and applications of MBI have evolved into a powerful and comprehensive framework that leads to rich and varied instruction with students directly in the…

  12. Model-Based Inquiry: A Buoyant Force Module for High School Physics Classes

    ERIC Educational Resources Information Center

    Neilson, Drew; Campbell, Todd; Allred, Benjamin

    2010-01-01

    Model-Based Inquiry (MBI) is an emergent instructional strategy that is gaining acceptance among science educators. This approach to learning realistically mirrors the work of scientists, who develop and test hypotheses to construct more sophisticated understandings of the natural world. This article details how the authors collaboratively taught…

  13. Model-based advice for mechanical ventilation: From research (INVENT) to product (Beacon Caresystem).

    PubMed

    Rees, Stephen E; Karbing, Dan S

    2015-01-01

    This paper describes the structure and functionality of a physiological model-based system for providing advice on the settings of mechanical ventilation. Use of the system is presented with examples of patients on support and control modes of mechanical ventilation. PMID:26737495

  14. Model-based processing for shallow ocean environments: The broadband problem

    SciTech Connect

    Candy, J.V.; Sullivan, E.J.

    1996-01-31

    Most acoustic sources found is the ocean environmental are spatially complex and broadband. When propagating in a shallow ocean these source characteristics complicate the analysis of received acoustic data considerably. The enhancement of broadband acoustic pressure- field measurements using a vertical array is discussed. Here a model- based approach is developed for a broadband source using a normal- mode propagation model.

  15. A Recursive, Reflective Instructional Design Model Based on Constructivist-Interpretivist Theory.

    ERIC Educational Resources Information Center

    Willis, Jerry, Ed.

    1995-01-01

    Discussion of instructional design focuses on a foundation for an alternative instructional design model based on social sciences theories from the constructivist family and on an interpretivist philosophy of science. Highlights include the role of language; and the nature of truth, or alternative conceptions of reality. (LRW)

  16. Developing Computer Model-Based Assessment of Chemical Reasoning: A Feasibility Study

    ERIC Educational Resources Information Center

    Liu, Xiufeng; Waight, Noemi; Gregorius, Roberto; Smith, Erica; Park, Mihwa

    2012-01-01

    This paper reports a feasibility study on developing computer model-based assessments of chemical reasoning at the high school level. Computer models are flash and NetLogo environments to make simultaneously available three domains in chemistry: macroscopic, submicroscopic, and symbolic. Students interact with computer models to answer assessment…

  17. Model-Based GN and C Simulation and Flight Software Development for Orion Missions beyond LEO

    NASA Technical Reports Server (NTRS)

    Odegard, Ryan; Milenkovic, Zoran; Henry, Joel; Buttacoli, Michael

    2014-01-01

    For Orion missions beyond low Earth orbit (LEO), the Guidance, Navigation, and Control (GN&C) system is being developed using a model-based approach for simulation and flight software. Lessons learned from the development of GN&C algorithms and flight software for the Orion Exploration Flight Test One (EFT-1) vehicle have been applied to the development of further capabilities for Orion GN&C beyond EFT-1. Continuing the use of a Model-Based Development (MBD) approach with the Matlab®/Simulink® tool suite, the process for GN&C development and analysis has been largely improved. Furthermore, a model-based simulation environment in Simulink, rather than an external C-based simulation, greatly eases the process for development of flight algorithms. The benefits seen by employing lessons learned from EFT-1 are described, as well as the approach for implementing additional MBD techniques. Also detailed are the key enablers for improvements to the MBD process, including enhanced configuration management techniques for model-based software systems, automated code and artifact generation, and automated testing and integration.

  18. MONA: An accurate two-phase well flow model based on phase slippage

    SciTech Connect

    Asheim, H.

    1984-10-01

    In two phase flow, holdup and pressure loss are related to interfacial slippage. A model based on the slippage concept has been developed and tested using production well data from Forties, the Ekofisk area, and flowline data from Prudhoe Bay. The model developed turned out considerably more accurate than the standard models used for comparison.

  19. Study on the Teaching Model Based on Multimedia and Network Environment

    ERIC Educational Resources Information Center

    Zhang, Deju

    2010-01-01

    Based on the analysis of the advantages of teaching model in the network environment, three teaching models based on multimedia and network environment, i.e. the teaching model of giving priority of lecturing, the teaching model of giving priority of independent learning and the teaching model of group learning, are discussed in the article, and…

  20. Exploring the Argumentation Pattern in Modeling-Based Learning about Apparent Motion of Mars

    ERIC Educational Resources Information Center

    Park, Su-Kyeong

    2016-01-01

    This study proposed an analytic framework for coding students' dialogic argumentation and investigated the characteristics of the small-group argumentation pattern observed in modeling-based learning. The participants were 122 second grade high school students in South Korea divided into an experimental and a comparison group. Modeling-based…