WorldWideScience

Sample records for density tagging velocimetry

  1. N2O molecular tagging velocimetry

    Science.gov (United States)

    ElBaz, A. M.; Pitz, R. W.

    2012-03-01

    A new seeded velocity measurement technique, N2O molecular tagging velocimetry (MTV), is developed to measure velocity in wind tunnels by photochemically creating an NO tag line. Nitrous oxide "laughing gas" is seeded into the air flow. A 193 nm ArF excimer laser dissociates the N2O to O(1D) that subsequently reacts with N2O to form NO. O2 fluorescence induced by the ArF laser "writes" the original position of the NO line. After a time delay, the shifted NO line is "read" by a 226-nm laser sheet and the velocity is determined by time-of-flight. At standard atmospheric conditions with 4% N2O in air, ˜1000 ppm of NO is photochemically created in an air jet based on experiment and simulation. Chemical kinetic simulations predict 800-1200 ppm of NO for 190-750 K at 1 atm and 850-1000 ppm of NO for 0.25-1 atm at 190 K. Decreasing the gas pressure (or increasing the temperature) increases the NO ppm level. The presence of humid air has no significant effect on NO formation. The very short NO formation time (helium) since the NO tag line is created by chemical reaction of N2O with O(1D) from N2O photodissociation and thus does not depend on the bulk gas composition.

  2. Hydroxyl Tagging Velocimetry for Rocket Plumes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A non-intrusive method for measuring velocities in a rocket exhaust is proposed in a joint effort by MetroLaser and Vanderbilt University. Hydroxyl Tagging...

  3. Comparison of Simultaneous PIV and Hydroxyl Tagging Velocimetry in Low Velocity Flows

    Science.gov (United States)

    Andre, Matthieu A.; Bardet, Philippe M.; Burns, Ross A.; Danehy, Paul M.

    2016-01-01

    Hydroxyl tagging velocimetry (HTV) is a molecular tagging velocimetry (MTV) technique that relies on the photo- dissociation of water vapor into OH radicals and their subsequent tracking using laser-induced fluorescence. At ambient temperature in air, the OH species lifetime is about 50 micro-s. The feasibility of using HTV for probing low- speed flows (a few m/s) is investigated by using an inert, heated gas as a means to increase the OH species lifetime. Unlike particle-based techniques, MTV does not suffer from tracer settling, which is particularly problematic at low speeds. Furthermore, the flow needs to be seeded with only a small mole fraction of water vapor, making it safer for both the user and facilities than other MTV techniques based on corrosive or toxic chemical tracers. HTV is demonstrated on a steam-seeded nitrogen jet at approximately 75 C in the laminar (Umean=3.31 m/s, Re=1,540), transitional (Umean=4.48 m/s, Re=2,039), and turbulent (Umean=6.91 m/s, Re=3,016) regimes at atmospheric pressure. The measured velocity profiles are compared with particle image velocimetry (PIV) measurements performed simultaneously with a second imager. Seeding for the PIV is achieved by introducing micron-sized water droplets into the flow with the steam; the same laser sheet is used for PIV and HTV to guarantee spatial and temporal overlap of the data. Optimizing each of these methods, however, requires conflicting operating conditions: higher temperatures benefit the HTV signals but reduce the available seed density for the PIV through evaporation. Nevertheless, data are found to agree within 10% for the instantaneous velocity profiles and within 5% for the mean profiles and demonstrate the feasibility of HTV for low-speed flows at moderate to high temperatures.

  4. Seedless velocimetry at 100  kHz with picosecond-laser electronic-excitation tagging.

    Science.gov (United States)

    Jiang, Naibo; Mance, Jason G; Slipchenko, Mikhail N; Felver, Josef J; Stauffer, Hans U; Yi, Tongxun; Danehy, Paul M; Roy, Sukesh

    2017-01-15

    Picosecond-laser electronic-excitation tagging (PLEET), a seedless picosecond-laser-based velocimetry technique, is demonstrated in non-reactive flows at a repetition rate of 100 kHz with a 1064 nm, 100 ps burst-mode laser. The fluorescence lifetime of the PLEET signal was measured in nitrogen, and the laser heating effects were analyzed. PLEET experiments with a free jet of nitrogen show the ability to measure multi-point flow velocity fluctuations at a 100 kHz detection rate or higher. Both spectral and dynamic mode decomposition analyses of velocity on a Ma=0.8 free jet show two dominant Strouhal numbers around 0.24 and 0.48, respectively, well within the shear-layer flapping frequencies of the free jets. This technique increases the laser-tagging repetition rate for velocimetry to hundreds of kilohertz. PLEET is suitable for subsonic through supersonic laminar- and turbulent-flow velocity measurements.

  5. Parametric Study to Improve Subpixel Accuracy of Nitric Oxide Tagging Velocimetry with Image Preprocessing

    Directory of Open Access Journals (Sweden)

    Ravi Teja Vedula

    2017-01-01

    Full Text Available Biacetyl phosphorescence has been the commonly used molecular tagging velocimetry (MTV technique to investigate in-cylinder flow evolution and cycle-to-cycle variations in an optical engine. As the phosphorescence of biacetyl tracer deteriorates in the presence of oxygen, nitrogen was adopted as the working medium in the past. Recently, nitrous oxide MTV technique was employed to measure the velocity profile of an air jet. The authors here plan to investigate the potential application of this technique for engine flow studies. A possible experimental setup for this task indicated different permutations of image signal-to-noise ratio (SNR and laser line width. In the current work, a numerical analysis is performed to study the effect of these two factors on displacement error in MTV image processing. Also, several image filtering techniques were evaluated and the performance of selected filters was analyzed in terms of enhancing the image quality and minimizing displacement errors. The flow displacement error without image preprocessing was observed to be inversely proportional to SNR and directly proportional to laser line width. The mean filter resulted in the smallest errors for line widths smaller than 9 pixels. The effect of filter size on subpixel accuracy showed that error levels increased as the filter size increased.

  6. Krypton tagging velocimetry in a turbulent Mach 2.7 boundary layer

    Science.gov (United States)

    Zahradka, D.; Parziale, N. J.; Smith, M. S.; Marineau, E. C.

    2016-05-01

    The krypton tagging velocimetry (KTV) technique is applied to the turbulent boundary layer on the wall of the "Mach 3 Calibration Tunnel" at Arnold Engineering Development Complex (AEDC) White Oak. Profiles of velocity were measured with KTV and Pitot-pressure probes in the Mach 2.7 turbulent boundary layer comprised of 99 % {N}2/1 % Kr at momentum-thickness Reynolds numbers of {Re}_{\\varTheta }= 800, 1400, and 2400. Agreement between the KTV- and Pitot-derived velocity profiles is excellent. The KTV and Pitot velocity data follow the law of the wall in the logarithmic region with application of the Van Driest I transformation. The velocity data are analyzed in the outer region of the boundary layer with the law of the wake and a velocity-defect law. KTV-derived streamwise velocity fluctuation measurements are reported and are consistent with data from the literature. To enable near-wall measurement with KTV (y/δ ≈ 0.1-0.2), an 800-nm longpass filter was used to block the 760.2-nm read-laser pulse. With the longpass filter, the 819.0-nm emission from the re-excited Kr can be imaged to track the displacement of the metastable tracer without imaging the reflection and scatter from the read-laser off of solid surfaces. To operate the Mach 3 AEDC Calibration Tunnel at several discrete unit Reynolds numbers, a modification was required and is described herein.

  7. Hypersonic Boundary Layer Measurements with Variable Blowing Rates Using Molecular Tagging Velocimetry

    Science.gov (United States)

    Bathel, Brett F.; Danehy, Paul M.; Johansen, Craig T.; Jones, Stephen B.; Goyne, Christopher P.

    2012-01-01

    Measurements of mean and instantaneous streamwise velocity profiles in a hypersonic boundary layer with variable rates of mass injection (blowing) of nitrogen dioxide (NO2) were obtained over a 10-degree half-angle wedge model. The NO2 was seeded into the flow from a slot located 29.4 mm downstream of the sharp leading edge. The top surface of the wedge was oriented at a 20 degree angle in the Mach 10 flow, yielding an edge Mach number of approximately 4.2. The streamwise velocity profiles and streamwise fluctuating velocity component profiles were obtained using a three-laser NO2->NO photolysis molecular tagging velocimetry method. Observed trends in the mean streamwise velocity profiles and profiles of the fluctuating component of streamwise velocity as functions of the blowing rate are described. An effort is made to distinguish between the effect of blowing rate and wall temperature on the measured profiles. An analysis of the mean velocity profiles for a constant blowing rate is presented to determine the uncertainty in the measurement for different probe laser delay settings. Measurements of streamwise velocity were made to within approximately 120 gm of the model surface. The streamwise spatial resolution in this experiment ranged from 0.6 mm to 2.6 mm. An improvement in the spatial precision of the measurement technique has been made, with spatial uncertainties reduced by about a factor of 2 compared to previous measurements. For the quiescent flow calibration measurements presented, uncertainties as low as 2 m/s are obtained at 95% confidence for long delay times (25 gs). For the velocity measurements obtained with the wind tunnel operating, average single-shot uncertainties of less than 44 m/s are obtained at 95% confidence with a probe laser delay setting of 1 gs. The measurements were performed in the 31-inch Mach 10 Air Tunnel at the NASA Langley Research Center.

  8. Trip-Induced Transition Measurements in a Hypersonic Boundary Layer Using Molecular Tagging Velocimetry

    Science.gov (United States)

    Bathel, Brett F.; Danehy, Paul M.; Jones, Stephen B.; Johansen, Craig T.; Goyne, Christopher P.

    2013-01-01

    Measurements of mean streamwise velocity, fluctuating streamwise velocity, and instantaneous streamwise velocity profiles in a hypersonic boundary layer were obtained over a 10-degree half-angle wedge model. A laser-induced fluorescence-based molecular tagging velocimetry technique was used to make the measurements. The nominal edge Mach number was 4.2. Velocity profiles were measured both in an untripped boundary layer and in the wake of a 4-mm diameter cylindrical tripping element centered 75.4 mm downstream of the sharp leading edge. Three different trip heights were investigated: k = 0.53 mm, k = 1.0 mm and k = 2.0 mm. The laminar boundary layer thickness at the position of the measurements was approximately 1 mm, though the exact thickness was dependent on Reynolds number and wall temperature. All of the measurements were made starting from a streamwise location approximately 18 mm downstream of the tripping element. This measurement region continued approximately 30 mm in the streamwise direction. Additionally, measurements were made at several spanwise locations. An analysis of flow features show how the magnitude, spatial location, and spatial growth of streamwise velocity instabilities are affected by parameters such as the ratio of trip height to boundary layer thickness and roughness Reynolds number. The fluctuating component of streamwise velocity measured along the centerline of the model increased from approximately 75 m/s with no trip to +/-225 m/s with a 0.53-mm trip, and to +/-240 m/s with a 1-mm trip, while holding the freestream Reynolds number constant. These measurements were performed in the 31-inch Mach 10 Air Tunnel at the NASA Langley Research Center.

  9. Iodine Tagging Velocimetry and Mechanism in the Hypersonic Near Wake of a MultiPurpose Crew Vehicle

    Science.gov (United States)

    Balla, R. Jeffrey

    2013-01-01

    This study demonstrates a new molecular tagging velocimetry (MTV) method for velocity measurements of high speed flow. It demonstrates offbody Iodine Tagging Velocimetry (ITV) in the hypersonic near wake of a MultiPurpose Crew Vehicle (MPCV) model. Experiments are performed in the NASA-Langley 31-inch Mach 10 air wind tunnel. A 0.5% I2 / N2 mixture is seeded on the leeward backshell of the model using a pressure tap. I2 laser-induced fluorescence is excited along a 5.5 mm line using an ArF excimer laser near 193 nm. Results indicate I2 absorbs at least 2 photons to produce iodine ions and electrons. These recombine as the tagged region is displaced downstream to produce I (2P3/2) whose emission is monitored at 206 nm. Results at P0 = 2.41 MPa (350 psi), T0 = 990K, and 10 micro-sec transit times produce velocities from 630-820 m/sec across the I2 seeded jet at a distance of 38.2 mm (25.5 jet diameters) downstream from the jet orifice. Maximum wake jet velocities near the shear layer are 59% of freestream velocity.

  10. Particle image velocimetry measurements and numerical modeling of a saline density current

    CSIR Research Space (South Africa)

    Gerber, G

    2011-03-01

    Full Text Available Particle image velocimetry scalar measurements were carried out on the body of a stably stratified density current with an inlet Reynolds number of 2,300 and bulk Richardson number of 0.1. These measurements allowed the mass and momentum transport...

  11. Particle Image Velocimetry Study of Density Current Fronts

    Science.gov (United States)

    Martin, Juan Ezequiel

    2009-01-01

    Gravity currents are flows that occur when a horizontal density difference causes fluid to move under the action of gravity; density currents are a particular case, for which the scalar causing the density difference is conserved. Flows with a strong effect of the horizontal density difference, even if only partially driven by it--such as the…

  12. Selective Two-Photon Absorptive Resonance Femtosecond-Laser Electronic-Excitation Tagging (STARFLEET) Velocimetry in Flow and Combustion Diagnostics

    Science.gov (United States)

    Jiang, Naibo; Halls, Benjamin R.; Stauffer, Hans U.; Roy, Sukesh; Danehy, Paul M.; Gord, James R.

    2016-01-01

    Selective Two-Photon Absorptive Resonance Femtosecond-Laser Electronic-Excitation Tagging (STARFLEET), a non-seeded ultrafast-laser-based velocimetry technique, is demonstrated in reactive and non-reactive flows. STARFLEET is pumped via a two-photon resonance in N2 using 202.25-nm 100-fs light. STARFLEET greatly reduces the per-pulse energy required (30 µJ/pulse) to generate the signature FLEET emission compared to the conventional FLEET technique (1.1 mJ/pulse). This reduction in laser energy results in less energy deposited in the flow, which allows for reduced flow perturbations (reactive and non-reactive), increased thermometric accuracy, and less severe damage to materials. Velocity measurements conducted in a free jet of N2 and in a premixed flame show good agreement with theoretical velocities and further demonstrate the significantly less-intrusive nature of STARFLEET.

  13. Particle image velocimetry in a variable density flow: application to a dynamically evolving microburst

    Science.gov (United States)

    Alahyari, A.; Longmire, E. K.

    1994-10-01

    A fondamental difficulty in the experimental study of gravity-driven flows using particle image velocimetry (PIV) and other optical diagnostic techniques is the problem associated with variations in thé refractive index within the fluid. This paper discusses a method by which the refractive indices of two fluids are matched while maintaining density differences of up to 4%. Aqueous solutions of glycerol and potassium phosphate are used to achieve precise index matching in the presence of mixed and unmixed constituents. The effectiveness of the method is verified in a PIV study of a laboratory-scale model of an atmospheric microburst where planes of two-dimensional velocity vectors are obtained in thé evolving flow field.

  14. Expression and purification of ELP-intein-tagged target proteins in high cell density E. coli fermentation

    Directory of Open Access Journals (Sweden)

    Wood David W

    2010-10-01

    Full Text Available Abstract Background Elastin-like polypeptides (ELPs are useful tools that can be used to non-chromatographically purify proteins. When paired with self-cleaving inteins, they can be used as economical self-cleaving purification tags. However, ELPs and ELP-tagged target proteins have been traditionally expressed using highly enriched media in shake flask cultures, which are generally not amenable to scale-up. Results In this work, we describe the high cell-density expression of self-cleaving ELP-tagged targets in a supplemented minimal medium at a 2.5 liter fermentation scale, with increased yields and purity compared to traditional shake flask cultures. This demonstration of ELP expression in supplemented minimal media is juxtaposed to previous expression of ELP tags in extract-based rich media. We also describe several sets of fed-batch conditions and their impact on ELP expression and growth medium cost. Conclusions By using fed batch E. coli fermentation at high cell density, ELP-intein-tagged proteins can be expressed and purified at high yield with low cost. Further, the impact of media components and fermentation design can significantly impact the overall process cost, particularly at large scale. This work thus demonstrates an important advances in the scale up of self-cleaving ELP tag-mediated processes.

  15. Kinetic Control of Histidine-Tagged Protein Surface Density on Supported Lipid Bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Nye, Jeffrey A. [Univ. of California, Berkeley, CA (United States); Groves, Jay T. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2008-02-28

    Nickel-chelating lipids are general tools for anchoring polyhistidine-tagged proteins to supported lipid bilayers (SLBs), but controversy exists over the stability of the protein-lipid attachment. In this study, we show that chelator lipids are suitable anchors for building stable, biologically active surfaces but that a simple Langmuirian model is insufficient to describe their behavior. Desorption kinetics from chelator lipids are governed by the valency of surface binding: monovalently bound proteins desorb within minutes (t1/2 ≈ 6 min), whereas polyvalently bound species remain bound for hours (t1/2 ≈ 12 h). Evolution between surface states is slow, so equilibrium is unlikely to be reached on experimental timescales. However, by tuning incubation conditions, the populations of each species can be kinetically controlled, providing a wide range of protein densities on SLBs with a single concentration of chelator lipid. In conclusion, we propose guidelines for the assembly of SLB surfaces functionalized with specific protein densities and demonstrate their utility in the formation of hybrid immunological synapses.

  16. Hydroxyl Tagging Velocimetry for Rocket Plumes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the need for non-intrusive sensors for rocket plume properties, we propose a laser-based velocity diagnostic that does not require seeding, works in high...

  17. Acoustic mapping velocimetry

    Science.gov (United States)

    Muste, M.; Baranya, S.; Tsubaki, R.; Kim, D.; Ho, H.; Tsai, H.; Law, D.

    2016-05-01

    Knowledge of sediment dynamics in rivers is of great importance for various practical purposes. Despite its high relevance in riverine environment processes, the monitoring of sediment rates remains a major and challenging task for both suspended and bed load estimation. While the measurement of suspended load is currently an active area of testing with nonintrusive technologies (optical and acoustic), bed load measurement does not mark a similar progress. This paper describes an innovative combination of measurement techniques and analysis protocols that establishes the proof-of-concept for a promising technique, labeled herein Acoustic Mapping Velocimetry (AMV). The technique estimates bed load rates in rivers developing bed forms using a nonintrusive measurements approach. The raw information for AMV is collected with acoustic multibeam technology that in turn provides maps of the bathymetry over longitudinal swaths. As long as the acoustic maps can be acquired relatively quickly and the repetition rate for the mapping is commensurate with the movement of the bed forms, successive acoustic maps capture the progression of the bed form movement. Two-dimensional velocity maps associated with the bed form migration are obtained by implementing algorithms typically used in particle image velocimetry to acoustic maps converted in gray-level images. Furthermore, use of the obtained acoustic and velocity maps in conjunction with analytical formulations (e.g., Exner equation) enables estimation of multidirectional bed load rates over the whole imaged area. This paper presents a validation study of the AMV technique using a set of laboratory experiments.

  18. Billfish Tagging

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SWFSC's constituent-based Billfish Tagging Program began in 1963 and since that time has provided conventional spaghetti type tags and tagging supplies to...

  19. 3D scanning particle tracking velocimetry

    Science.gov (United States)

    Hoyer, Klaus; Holzner, Markus; Lüthi, Beat; Guala, Michele; Liberzon, Alexander; Kinzelbach, Wolfgang

    2005-11-01

    In this article, we present an experimental setup and data processing schemes for 3D scanning particle tracking velocimetry (SPTV), which expands on the classical 3D particle tracking velocimetry (PTV) through changes in the illumination, image acquisition and analysis. 3D PTV is a flexible flow measurement technique based on the processing of stereoscopic images of flow tracer particles. The technique allows obtaining Lagrangian flow information directly from measured 3D trajectories of individual particles. While for a classical PTV the entire region of interest is simultaneously illuminated and recorded, in SPTV the flow field is recorded by sequential tomographic high-speed imaging of the region of interest. The advantage of the presented method is a considerable increase in maximum feasible seeding density. Results are shown for an experiment in homogenous turbulence and compared with PTV. SPTV yielded an average 3,500 tracked particles per time step, which implies a significant enhancement of the spatial resolution for Lagrangian flow measurements.

  20. Tag questions Tag questions

    Directory of Open Access Journals (Sweden)

    David Brazil

    2008-04-01

    Full Text Available The so-called 'tag' structures of English have received a lot of attention in language teaching programmes, attention that is not hard to justify when one considers the problems and anxiety they can occasion for many foreign learners. Most teachers one speaks to seem fairly willing to agree, however, that traditional treatments of the topic leave much to be desired. It happens, also, that, when considered collectively, the tags and some related phenomena have a special heoretical interest. For they constitute a field in which it seems essential to bring together insights that derive from the study of several aspects of linguistic organisation, aspects which in some recent work have been held to need distinctive kinds of descriptive category to handle. Traditional treatments have found it necessary to recognise different syntactic types (e.g. 'same polarity' and 'reversed polarity' tags and ifferent intonational treatments ("falling'and 'rising' tag; while the way the communicative significance of the various permutations is described normally requires reference to the expectations they signal regarding the immediately following behaviour of the other party (in the common phrase, 'What kind of answer they expect'. This last consideration places the matter squarely in the arena of recent work on the analysis of interactive discourse. The so-called 'tag' structures of English have received a lot of attention in language teaching programmes, attention that is not hard to justify when one considers the problems and anxiety they can occasion for many foreign learners. Most teachers one speaks to seem fairly willing to agree, however, that traditional treatments of the topic leave much to be desired. It happens, also, that, when considered collectively, the tags and some related phenomena have a special heoretical interest. For they constitute a field in which it seems essential to bring together insights that derive from the study of several aspects

  1. Rainbow Particle Imaging Velocimetry

    KAUST Repository

    Xiong, Jinhui

    2017-04-27

    Despite significant recent progress, dense, time-resolved imaging of complex, non-stationary 3D flow velocities remains an elusive goal. This work tackles this problem by extending an established 2D method, Particle Imaging Velocimetry, to three dimensions by encoding depth into color. The encoding is achieved by illuminating the flow volume with a continuum of light planes (a “rainbow”), such that each depth corresponds to a specific wavelength of light. A diffractive component in the camera optics ensures that all planes are in focus simultaneously. With this setup, a single color camera is sufficient to track 3D trajectories of particles by combining 2D spatial and 1D color information. For reconstruction, this thesis derives an image formation model for recovering stationary 3D particle positions. 3D velocity estimation is achieved with a variant of 3D optical flow that accounts for both physical constraints as well as the rainbow image formation model. The proposed method is evaluated by both simulations and an experimental prototype setup.

  2. Fast super-resolution imaging with ultra-high labeling density achieved by joint tagging super-resolution optical fluctuation imaging.

    Science.gov (United States)

    Zeng, Zhiping; Chen, Xuanze; Wang, Hening; Huang, Ning; Shan, Chunyan; Zhang, Hao; Teng, Junlin; Xi, Peng

    2015-02-10

    Previous stochastic localization-based super-resolution techniques are largely limited by the labeling density and the fidelity to the morphology of specimen. We report on an optical super-resolution imaging scheme implementing joint tagging using multiple fluorescent blinking dyes associated with super-resolution optical fluctuation imaging (JT-SOFI), achieving ultra-high labeling density super-resolution imaging. To demonstrate the feasibility of JT-SOFI, quantum dots with different emission spectra were jointly labeled to the tubulin in COS7 cells, creating ultra-high density labeling. After analyzing and combining the fluorescence intermittency images emanating from spectrally resolved quantum dots, the microtubule networks are capable of being investigated with high fidelity and remarkably enhanced contrast at sub-diffraction resolution. The spectral separation also significantly decreased the frame number required for SOFI, enabling fast super-resolution microscopy through simultaneous data acquisition. As the joint-tagging scheme can decrease the labeling density in each spectral channel, thereby bring it closer to single-molecule state, we can faithfully reconstruct the continuous microtubule structure with high resolution through collection of only 100 frames per channel. The improved continuity of the microtubule structure is quantitatively validated with image skeletonization, thus demonstrating the advantage of JT-SOFI over other localization-based super-resolution methods.

  3. Fast Super-Resolution Imaging with Ultra-High Labeling Density Achieved by Joint Tagging Super-Resolution Optical Fluctuation Imaging

    Science.gov (United States)

    Zeng, Zhiping; Chen, Xuanze; Wang, Hening; Huang, Ning; Shan, Chunyan; Zhang, Hao; Teng, Junlin; Xi, Peng

    2015-01-01

    Previous stochastic localization-based super-resolution techniques are largely limited by the labeling density and the fidelity to the morphology of specimen. We report on an optical super-resolution imaging scheme implementing joint tagging using multiple fluorescent blinking dyes associated with super-resolution optical fluctuation imaging (JT-SOFI), achieving ultra-high labeling density super-resolution imaging. To demonstrate the feasibility of JT-SOFI, quantum dots with different emission spectra were jointly labeled to the tubulin in COS7 cells, creating ultra-high density labeling. After analyzing and combining the fluorescence intermittency images emanating from spectrally resolved quantum dots, the microtubule networks are capable of being investigated with high fidelity and remarkably enhanced contrast at sub-diffraction resolution. The spectral separation also significantly decreased the frame number required for SOFI, enabling fast super-resolution microscopy through simultaneous data acquisition. As the joint-tagging scheme can decrease the labeling density in each spectral channel, thereby bring it closer to single-molecule state, we can faithfully reconstruct the continuous microtubule structure with high resolution through collection of only 100 frames per channel. The improved continuity of the microtubule structure is quantitatively validated with image skeletonization, thus demonstrating the advantage of JT-SOFI over other localization-based super-resolution methods. PMID:25665878

  4. Echo particle image velocimetry.

    Science.gov (United States)

    DeMarchi, Nicholas; White, Christopher

    2012-12-27

    The transport of mass, momentum, and energy in fluid flows is ultimately determined by spatiotemporal distributions of the fluid velocity field.(1) Consequently, a prerequisite for understanding, predicting, and controlling fluid flows is the capability to measure the velocity field with adequate spatial and temporal resolution.(2) For velocity measurements in optically opaque fluids or through optically opaque geometries, echo particle image velocimetry (EPIV) is an attractive diagnostic technique to generate "instantaneous" two-dimensional fields of velocity.(3,4,5,6) In this paper, the operating protocol for an EPIV system built by integrating a commercial medical ultrasound machine(7) with a PC running commercial particle image velocimetry (PIV) software(8) is described, and validation measurements in Hagen-Poiseuille (i.e., laminar pipe) flow are reported. For the EPIV measurements, a phased array probe connected to the medical ultrasound machine is used to generate a two-dimensional ultrasound image by pulsing the piezoelectric probe elements at different times. Each probe element transmits an ultrasound pulse into the fluid, and tracer particles in the fluid (either naturally occurring or seeded) reflect ultrasound echoes back to the probe where they are recorded. The amplitude of the reflected ultrasound waves and their time delay relative to transmission are used to create what is known as B-mode (brightness mode) two-dimensional ultrasound images. Specifically, the time delay is used to determine the position of the scatterer in the fluid and the amplitude is used to assign intensity to the scatterer. The time required to obtain a single B-mode image, t, is determined by the time it take to pulse all the elements of the phased array probe. For acquiring multiple B-mode images, the frame rate of the system in frames per second (fps) = 1/δt. (See 9 for a review of ultrasound imaging.) For a typical EPIV experiment, the frame rate is between 20-60 fps

  5. Fast Super-Resolution Imaging with Ultra-High Labeling Density Achieved by Joint Tagging Super-Resolution Optical Fluctuation Imaging (JT-SOFI)

    CERN Document Server

    Zeng, Zhiping; Wang, Hening; Huang, Ning; Shan, Chunyan; Zhang, Hao; Teng, Junlin; Xi, Peng

    2015-01-01

    Previous stochastic localization-based super-resolution techniques are largely limited by the labeling density and the fidelity to the morphology of specimen. We report on an optical super-resolution imaging scheme implementing joint tagging using multiple fluorescent blinking dyes associated with super-resolution optical fluctuation imaging (JT-SOFI), achieving ultra-high labeling density super-resolution imaging. To demonstrate the feasibility of JT-SOFI, quantum dots with different emission spectra were jointly labeled to the tubulin in COS7 cells, creating ultra-high density labeling. After analyzing and combining the fluorescence intermittency images emanating from spectrally resolved quantum dots, the microtubule networks are capable of being investigated with high fidelity and remarkably enhanced contrast at sub-diffraction resolution. The spectral separation also significantly decreased the frame number required for SOFI, enabling fast super-resolution microscopy through simultaneous data acquisition....

  6. Spectral Tagging

    Energy Technology Data Exchange (ETDEWEB)

    Smartt, Heidi A. [Sandia National Laboratories (United States)

    2003-05-01

    This research examines the feasibility of spectral tagging, which involves modifying the spectral signature of a target, e.g. by mixing an additive with the target's paint. The target is unchanged to the human eye, but the tag is revealed when viewed with a spectrometer. This project investigates a layer of security that is not obvious, and therefore easy to conceal. The result is a tagging mechanism that is difficult to counterfeit. Uniquely tagging an item is an area of need in safeguards and security and non-proliferation. The powdered forms of the minerals lapis lazuli and olivine were selected as the initial test tags due to their availability and uniqueness in the visible to near-infrared spectral region. They were mixed with paints and applied to steel. In order to verify the presence of the tags quantitatively, the data from the spectrometer was input into unmixing models and signal detection algorithms. The mixture with the best results was blue paint mixed with lapis lazuli and olivine. The tag had a 0% probability of false alarm and a 100% probability of detection. The research proved that spectral tagging is feasible, although certain tag/paint mixtures are more detectable than others.

  7. 3D scanning particle tracking velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hoyer, Klaus; Holzner, Markus; Guala, Michele; Liberzon, Alexander; Kinzelbach, Wolfgang [Swiss Federal Institut of Technology Zurich, Institut fuer Hydromechanik und Wasserwirtschaft, Zuerich (Switzerland); Luethi, Beat [Risoe National Laboratory, Roskilde (Denmark)

    2005-11-01

    In this article, we present an experimental setup and data processing schemes for 3D scanning particle tracking velocimetry (SPTV), which expands on the classical 3D particle tracking velocimetry (PTV) through changes in the illumination, image acquisition and analysis. 3D PTV is a flexible flow measurement technique based on the processing of stereoscopic images of flow tracer particles. The technique allows obtaining Lagrangian flow information directly from measured 3D trajectories of individual particles. While for a classical PTV the entire region of interest is simultaneously illuminated and recorded, in SPTV the flow field is recorded by sequential tomographic high-speed imaging of the region of interest. The advantage of the presented method is a considerable increase in maximum feasible seeding density. Results are shown for an experiment in homogenous turbulence and compared with PTV. SPTV yielded an average 3,500 tracked particles per time step, which implies a significant enhancement of the spatial resolution for Lagrangian flow measurements. (orig.)

  8. FLEET Velocimetry Measurements on a Transonic Airfoil

    Science.gov (United States)

    Burns, Ross A.; Danehy, Paul M.

    2017-01-01

    Femtosecond laser electronic excitation tagging (FLEET) velocimetry was used to study the flowfield around a symmetric, transonic airfoil in the NASA Langley 0.3-m TCT facility. A nominal Mach number of 0.85 was investigated with a total pressure of 125 kPa and total temperature of 280 K. Two-components of velocity were measured along vertical profiles at different locations above, below, and aft of the airfoil at angles of attack of 0 deg, 3.5 deg, and 7deg. Measurements were assessed for their accuracy, precision, dynamic range, spatial resolution, and overall measurement uncertainty in the context of the applied flowfield. Measurement precisions as low as 1 m/s were observed, while overall uncertainties ranged from 4 to 5 percent. Velocity profiles within the wake showed sufficient accuracy, precision, and sensitivity to resolve both the mean and fluctuating velocities and general flow physics such as shear layer growth. Evidence of flow separation is found at high angles of attack.

  9. Efficacy of Barium-Based Fecal Tagging for CT Colonography: a Comparison between the Use of High and Low Density Barium Suspensions in a Korean Population - a Preliminary Study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Ju; Park, Seong Ho; Lee, Seung Soo; Byeon, Jeong Sik; Kim, Jung Hoon; Kim, Yeoung Nam; Kim, Ah Young; Ha, Hyun Kwon [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Choi, Eugene K. [University of California Los Angeles, Los Angeles (United States)

    2009-02-15

    This preliminarily study was designed to determine and to compare the efficacy of two commercially available barium-based fecal tagging agents for CT colonography (CTC) (high-density [40% w/v] and low-density [4.6% w/v] barium suspensions) in a population in Korea. In a population with an identified with an average-risk for colorectal cancer, 15 adults were administered three doses of 20 ml 40% w/v barium for fecal tagging (group I) and 15 adults were administered three doses of 200 ml 4.6% w/v barium (group II) for fecal tagging. Excluding five patients in group I and one patient in group II that left the study, ten patients in group I and 14 patients in group II were finally included in the analysis. Two experienced readers evaluated the CTC images in consensus regarding the degree of tagging of stool pieces 6 mm or larger. Stool pieces were confirmed with the use of standardized CTC criteria or the absence of matched lesions as seen on colonoscopy. The rates of complete fecal tagging were analyzed on a per-lesion and a per-segment basis and were compared between the patients in the two groups. Per-lesion rates of complete fecal tagging were 52% (22 of 42; 95% CI, 37.7-66.6%) in group I and 78% (28 of 36; 95% CI, 61.7-88.5%) in group II. The difference between the two groups did not reach statistical significance (p = 0.285). The per-segment rates of complete tagging were 33% (6 of 18; 95% CI, 16.1%-56.4%) in group I and 60% (9 of 15; 95% CI, 35.7%-80.3%) in group II; again, the difference between the two groups did not reach statistical significance (p = 0.171). Barium-based fecal tagging using both the 40% w/v and the 4.6% w/v barium suspensions showed moderate tagging efficacy. The preliminary comparison did not demonstrate a statistically significant difference in the tagging efficacy between the use of the two tagging agents, despite the tendency toward better tagging with the use of the 4.6% w/v barium suspension.

  10. Hepatitis C virus expressing flag-tagged envelope protein 2 has unaltered infectivity and density, is specifically neutralized by flag antibodies and can be purified by affinity chromatography

    DEFF Research Database (Denmark)

    Prentø, Jannick Cornelius; Bukh, Jens

    2011-01-01

    , flag-tagged viruses had drastically altered properties, and purification yield was low. In this study, we found that insertion of flag tag at the N-terminus of E2 in HCV recombinant J6/JFH1 did not affect viability in Huh7.5 cells, and that flag-tagged virus had physiochemical properties similar...

  11. Velocimetry signal synthesis with fringen.

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Daniel H., III

    2011-02-01

    An important part of velocimetry analysis is the recovery of a known velocity history from simulated data signals. The fringen program synthesizes VISAR and PDV signals, given a specified velocity history, using exact formulations for the optical signal. Time-dependent light conditions, non-ideal measurement conditions, and various diagnostic limitations (noise, etc.) may be incorporated into the simulated signals. This report describes the fringen program, which performs forward VISAR (Velocity Interferometer System for Any Reflector) and PDV (Photonic Doppler Velocimetry, also known as heterodyne velocimetry) analysis. Nearly all effects that might occur in VISAR/PDV measurement of a single velocity can be modeled by fringen. The program operates in MATLAB, either within a graphical interface or as a user-callable function. The current stable version of fringen is 0.3, which was released in October 2010. The following sections describe the operation and use of fringen. Section 2 gives a brief overview of VISAR and PDV synthesis. Section 3 illustrates the graphical and console interface of fringen. Section 4 presents several example uses of the program. Section 5 summarizes program capabilities and discusses potential future work.

  12. Review of Fluorescence-Based Velocimetry Techniques to Study High-Speed Compressible Flows

    Science.gov (United States)

    Bathel, Brett F.; Johansen, Criag; Inman, Jennifer A.; Jones, Stephen B.; Danehy, Paul M.

    2013-01-01

    This paper reviews five laser-induced fluorescence-based velocimetry techniques that have been used to study high-speed compressible flows at NASA Langley Research Center. The techniques discussed in this paper include nitric oxide (NO) molecular tagging velocimetry (MTV), nitrogen dioxide photodissociation (NO2-to-NO) MTV, and NO and atomic oxygen (O-atom) Doppler-shift-based velocimetry. Measurements of both single-component and two-component velocity have been performed using these techniques. This paper details the specific application and experiment for which each technique has been used, the facility in which the experiment was performed, the experimental setup, sample results, and a discussion of the lessons learned from each experiment.

  13. Femtosecond laser electronic excitation tagging for aerodynamic and thermodynamic measurements

    Science.gov (United States)

    Calvert, Nathan David

    This thesis presents applications of Femtosecond Laser Electronic Excitation Tagging (FLEET) to a variety of aerodynamic and thermodynamic measurements. FLEET tagged line characteristics such as intensity, width and spectral features are investigated in various flow conditions (pressure, temperature, velocity, steadiness, etc.) and environments (gas composition) for both temporally and spatially instantaneous and averaged data. Special attention is drawn to the nature of first and second positive systems of molecular nitrogen and the ramifications on FLEET measurements. Existing laser-based diagnostic techniques are summarized and FLEET is directly compared with Particle Image Velocimetry (PIV) in various low speed flows. Multidimensional velocity, acceleration, vorticity and other flow parameters are extracted in supersonic free jets and within an enclosed in-draft tunnel test section. Probability distribution functions of the mean and standard deviation of critical flow parameters are unveiled by utilizing a Bayesian statistical framework wherein likelihood functions are established from prior and posterior distributions. Advanced image processing techniques based on fuzzy logic are applied to single-shot FLEET images with low signal-to-noise ratio to improve image quality and reduce uncertainty in data processing algorithms. Lastly, FLEET second positive and first negative emission are considered at a wide range of pressures to correct for changes in select rovibrational peak magnitude and shape due to density from which bulk gas temperature may be extracted.

  14. Ultrasound Imaging Velocimetry: a review

    Science.gov (United States)

    Poelma, Christian

    2017-01-01

    Whole-field velocity measurement techniques based on ultrasound imaging (a.k.a. `ultrasound imaging velocimetry' or `echo-PIV') have received significant attention from the fluid mechanics community in the last decade, in particular because of their ability to obtain velocity fields in flows that elude characterisation by conventional optical methods. In this review, an overview is given of the history, typical components and challenges of these techniques. The basic principles of ultrasound image formation are summarised, as well as various techniques to estimate flow velocities; the emphasis is on correlation-based techniques. Examples are given for a wide range of applications, including in vivo cardiovascular flow measurements, the characterisation of sediment transport and the characterisation of complex non-Newtonian fluids. To conclude, future opportunities are identified. These encompass not just optimisation of the accuracy and dynamic range, but also extension to other application areas.

  15. Fuzzy logic particle tracking velocimetry

    Science.gov (United States)

    Wernet, Mark P.

    1993-01-01

    Fuzzy logic has proven to be a simple and robust method for process control. Instead of requiring a complex model of the system, a user defined rule base is used to control the process. In this paper the principles of fuzzy logic control are applied to Particle Tracking Velocimetry (PTV). Two frames of digitally recorded, single exposure particle imagery are used as input. The fuzzy processor uses the local particle displacement information to determine the correct particle tracks. Fuzzy PTV is an improvement over traditional PTV techniques which typically require a sequence (greater than 2) of image frames for accurately tracking particles. The fuzzy processor executes in software on a PC without the use of specialized array or fuzzy logic processors. A pair of sample input images with roughly 300 particle images each, results in more than 200 velocity vectors in under 8 seconds of processing time.

  16. Tag Correspondence Model for User Tag Suggestion

    Institute of Scientific and Technical Information of China (English)

    涂存超; 刘知远; 孙茂松

    2015-01-01

    Some microblog services encourage users to annotate themselves with multiple tags, indicating their attributes and interests. User tags play an important role for personalized recommendation and information retrieval. In order to better understand the semantics of user tags, we propose Tag Correspondence Model (TCM) to identify complex correspondences of tags from the rich context of microblog users. The correspondence of a tag is referred to as a unique element in the context which is semantically correlated with this tag. In TCM, we divide the context of a microblog user into various sources (such as short messages, user profile, and neighbors). With a collection of users with annotated tags, TCM can automatically learn the correspondences of user tags from multiple sources. With the learned correspondences, we are able to interpret implicit semantics of tags. Moreover, for the users who have not annotated any tags, TCM can suggest tags according to users’ context information. Extensive experiments on a real-world dataset demonstrate that our method can effciently identify correspondences of tags, which may eventually represent semantic meanings of tags.

  17. Shark Tagging Activities.

    Science.gov (United States)

    Current: The Journal of Marine Education, 1998

    1998-01-01

    In this group activity, children learn about the purpose of tagging and how scientists tag a shark. Using a cut-out of a shark, students identify, measure, record data, read coordinates, and tag a shark. Includes introductory information about the purpose of tagging and the procedure, a data sheet showing original tagging data from Tampa Bay, and…

  18. Tags, micro-tags and tag editing: improving internet search

    Science.gov (United States)

    Rogowitz, Bernice E.; Topkara, Mercan

    2009-02-01

    Social tagging is an emerging methodology that allows individual users to assign semantic keywords to content on the web. Popular web services allow the community of users to search for content based on these user-defined tags. Tags are typically attached to a whole entity such as a web page (e.g., del.icio.us), a video (e.g., YouTube), a product description (e.g., Amazon) or a photograph (e.g., Flickr). However, finding specific information within a whole entity can be a difficult, time-intensive process. This is especially true for content such as video, where the information sought may be a small segment within a very long presentation. Moreover, the tags provided by a community of users may be incorrect, conflicting, or incomplete when used as search terms. In this paper we introduce a system that allows users to create "micro-tags," that is, semantic markers that are attached to subsets of information. These micro-tags give the user the ability to direct attention to specific subsets within a larger and more complex entity, and the set of micro-tags provides a more nuanced description of the full content. Also, when these micro-tags are used as search terms, there is no need to do a serial search of the content, since micro-tags draw attention to the semantic content of interest. This system also provides a mechanism that allows users in the community to edit and delete each others' tags, using the community to refine and improve tag quality. We will also report on empirical studies that demonstrate the value of micro-tagging and tag editing and explore the role micro-tags and tag editing will play in future applications.

  19. Yellowtail Tagging Data (MRDBS)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Yellowtail Flounder Tagging Program began in 2003 and works with commercial fishermen to tag and release yellowtaiI flounder with pink and yellow disc tags or...

  20. Rubidium atomic line filtered (RALF) Doppler velocimetry

    Science.gov (United States)

    Fajardo, Mario E.; Molek, Christopher D.; Vesely, Annamaria L.

    2017-01-01

    We report recent improvements to our Rubidium Atomic Line Filtered (RALF) Doppler velocimetry apparatus [M.E. Fajardo, C.D. Molek, and A.L. Vesely, J. Appl. Phys. 118, 144901 (2015)]. RALF is a high-velocity and high-acceleration adaptation of the Doppler Global Velocimetry method for measuring multi-dimensional velocity vector flow fields, which was developed in the 1990s by aerodynamics researchers [H. Komine, U.S. Patent #4,919,536]. Laser velocimetry techniques in common use within the shock physics community (e.g. VISAR, Fabry-Pérot, PDV) decode the Doppler shift of light reflected from a moving surface via interference phenomena. In contrast, RALF employs a completely different physical principle: the frequency-dependent near-resonant optical transmission of a Rb/N2 gas cell, to encode the Doppler shift of reflected λ0 ≈ 780.24 nm light directly onto the transmitted light intensity. Thus, RALF is insensitive to minor changes to the optical pathlengths and transit times of the Doppler shifted light, which promises a number of practical advantages in imaging velocimetry applications. The single-point RALF proof-of-concept apparatus described here is fiber optic based, and our most recent modifications include the incorporation of a larger bandwidth detection system, and a second 780 nm laser for simultaneous upshifted-PDV (UPDV) measurements. We report results for the laser driven launch of a 10-μm-thick aluminum flyer which show good agreement between the RALF and UPDV velocity profiles, within the limitations of the admittedly poor signal:noise ratio (SNR) RALF data.

  1. Laser Velocimetry of Chemical Vapor Deposition Flows

    Science.gov (United States)

    1993-01-01

    Laser velocimetry (LV) is being used to measure the gas flows in chemical vapor deposition (CVD) reactors. These gas flow measurements can be used to improve industrial processes in semiconductor and optical layer deposition and to validate numerical models. Visible in the center of the picture is the graphite susceptor glowing orange-hot at 600 degrees C. It is inductively heated via the copper cool surrounding the glass reactor.

  2. Velocimetry Overview for visitors from the DOD

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Matthew E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Physics Division; Holtkamp, David Bruce [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Physics Division

    2016-08-19

    We are in the midst of a transformative period in which technological advances are making fundamental changes in the measurement techniques that form the backbone of nuclear weapon certification. Optical velocimetry has replaced electrical shorting pins in “Hydrotests,” which measure the dynamic implosion process. This advance has revolutionized nuclear weapons certification during the last 5 years. We can now measure the implosion process that drives a nuclear detonation with many orders of magnitude more resolution in both space and time than was possible just 10 years ago. It has been compared to going from Morse Code to HDTV, resulting in a dozen or more improvements in models of these weapons. These Hydrotests are carried out at LANL, LLNL and the NNSS, with the later holding the important role of allowing us to test with nuclear materials, in sub-critical configurations (i.e., no yield.) Each of these institutions has largely replaced pins with hundreds of channels of optical velocimetry. Velocimetry is non-contact and is used simultaneously with the X-ray capability of these facilities. The U1-a facility at NNSS pioneered this approach in the Gemini series in 2012, and continues to lead, both in channel count and technological advances. Close cooperation among LANL, LLNL and NSTec in these advances serves the complex by leveraging capabilities across sites and accelerating the pace of technical improvements.

  3. Particle Streak Velocimetry of Supersonic Nozzle Flows

    Science.gov (United States)

    Willits, J. D.; Pourpoint, T. L.

    2016-01-01

    A novel velocimetry technique to probe the exhaust flow of a laboratory scale combustor is being developed. The technique combines the advantages of standard particle velocimetry techniques and the ultra-fast imaging capabilities of a streak camera to probe high speed flows near continuously with improved spatial and velocity resolution. This "Particle Streak Velocimetry" technique tracks laser illuminated seed particles at up to 236 picosecond temporal resolution allowing time-resolved measurement of one-dimensional flows exceeding 2000 m/s as are found in rocket nozzles and many other applications. Developmental tests with cold nitrogen have been performed to validate and troubleshoot the technique with supersonic flows of much lower velocity and without background noise due to combusting flow. Flow velocities on the order of 500 m/s have been probed with titanium dioxide particles and a continuous-wave laser diode. Single frame images containing multiple streaks are analyzed to find the average slope of all incident particles corresponding to the centerline axial flow velocity. Long term objectives for these tests are correlation of specific impulse to theoretical combustion predictions and direct comparisons between candidate green fuels and the industry standard, monomethylhydrazine, each tested under identical conditions.

  4. Gillnet Tag Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Certain fishery management programs require vessels to obtain gillnet tags to be used with their gillnet gear. Gillnet tag data is a collection of requests and...

  5. North Pacific Albacore Tagging

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Conventional tagging data are available from 1971 to 1996. Electronic tagging data are available from 2000 to present. The data are managed by SWFSC in Access...

  6. Donor Tag Game

    Science.gov (United States)

    ... Donor Community > Games > Donor Tag Game Donor Tag Game This feature requires version 6 or later of ... of Needles LGBTQ+ Donors Blood Donor Community SleevesUp Games Facebook Avatars and Badges Banners eCards Make a ...

  7. Cooperative Tagging Center (CTC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Cooperative Tagging Center (CTC) began as the Cooperative Game Fish Tagging Program (GTP) at Woods Hole Oceanographic Institute (WHOI) in 1954. The GTP was...

  8. Satellite Tags- Hawaii EEZ

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Satellite tagging was implemented in 2013. Satellite tagging is conducted using a Dan Inject air rifle and deployment arrows designed by Wildlife Computers. Two...

  9. Three-dimensional synthetic aperture particle image velocimetry

    Science.gov (United States)

    Belden, Jesse; Truscott, Tadd T.; Axiak, Michael C.; Techet, Alexandra H.

    2010-12-01

    We present a new method for resolving three-dimensional (3D) fluid velocity fields using a technique called synthetic aperture particle image velocimetry (SAPIV). By fusing methods from the imaging community pertaining to light field imaging with concepts that drive experimental fluid mechanics, SAPIV overcomes many of the inherent challenges of 3D particle image velocimetry (3D PIV). This method offers the ability to digitally refocus a 3D flow field at arbitrary focal planes throughout a volume. The viewable out-of-plane dimension (Z) can be on the same order as the viewable in-plane dimensions (X-Y), and these dimensions can be scaled from tens to hundreds of millimeters. Furthermore, the digital refocusing provides the ability to 'see-through' partial occlusions, enabling measurements in densely seeded volumes. The advantages are achieved using a camera array (typically at least five cameras) to image the seeded fluid volume. The theoretical limits on refocused plane spacing and viewable depth are derived and explored as a function of camera optics and spacing of the array. A geometric optics model and simulated PIV images are used to investigate system performance for various camera layouts, measurement volume sizes and seeding density; performance is quantified by the ability to reconstruct the 3D intensity field, and resolve 3D vector fields in densely seeded simulated flows. SAPIV shows the ability to reconstruct fields with high seeding density and large volume size. Finally, results from an experimental implementation of SAPIV using a low cost eight-camera array to study a vortex ring in a 65 × 40 × 32 mm3 volume are presented. The 3D PIV results are compared with 2D PIV data to demonstrate the capability of the 3D SAPIV technique.

  10. Cutaneous skin tag

    Science.gov (United States)

    Skin tag; Acrochordon; Fibroepithelial polyp ... have diabetes. They are thought to occur from skin rubbing against skin. ... The tag sticks out of the skin and may have a short, narrow stalk connecting it to the surface of the skin. Some skin tags are as long as ...

  11. High-density SNP screen of sodium channel genes by haplotype tagging and DNA pooling for association with idiopathic generalized epilepsy.

    Science.gov (United States)

    Makoff, Andrew; Lai, Teck; Barratt, Catherine; Valentin, Antonio; Moran, Nick; Asherson, Philip; Nashef, Lina

    2010-04-01

    We have investigated seven voltage-gated sodium channel genes for association with idiopathic generalized epilepsy (IGE). Probands and control DNA were grouped into pools and used to screen 85 single-nucleotide polymorphisms (SNPs), mostly HapMap SNPs tagging the common variation in these genes. Twelve SNPs exhibiting an allele frequency difference between pools were genotyped individually in our sample of 232 probands, 313 controls, and 95 parent-proband trios. Two SNPs, in SCN1A and SCN8A, were associated by allele and genotype at nominal level of significance, but were not significant after Bonferroni correction. Two SCN2A SNPs (rs3943809 and rs16850331) were associated by case-control with a subgroup with IGE and history of febrile seizures and also by transmission disequilibrium test (TDT) in parent-proband trios. Both SNPs are part of a linkage disequilibrium (LD) cluster of 38 SNPs, but none are obvious functional variants. The association of rs3943809 with the febrile seizure subgroup (p = 0.0004) remains significant after the conservative Bonferroni correction for multiple testing.

  12. Extracting tag hierarchies.

    Directory of Open Access Journals (Sweden)

    Gergely Tibély

    Full Text Available Tagging items with descriptive annotations or keywords is a very natural way to compress and highlight information about the properties of the given entity. Over the years several methods have been proposed for extracting a hierarchy between the tags for systems with a "flat", egalitarian organization of the tags, which is very common when the tags correspond to free words given by numerous independent people. Here we present a complete framework for automated tag hierarchy extraction based on tag occurrence statistics. Along with proposing new algorithms, we are also introducing different quality measures enabling the detailed comparison of competing approaches from different aspects. Furthermore, we set up a synthetic, computer generated benchmark providing a versatile tool for testing, with a couple of tunable parameters capable of generating a wide range of test beds. Beside the computer generated input we also use real data in our studies, including a biological example with a pre-defined hierarchy between the tags. The encouraging similarity between the pre-defined and reconstructed hierarchy, as well as the seemingly meaningful hierarchies obtained for other real systems indicate that tag hierarchy extraction is a very promising direction for further research with a great potential for practical applications. Tags have become very prevalent nowadays in various online platforms ranging from blogs through scientific publications to protein databases. Furthermore, tagging systems dedicated for voluntary tagging of photos, films, books, etc. with free words are also becoming popular. The emerging large collections of tags associated with different objects are often referred to as folksonomies, highlighting their collaborative origin and the "flat" organization of the tags opposed to traditional hierarchical categorization. Adding a tag hierarchy corresponding to a given folksonomy can very effectively help narrowing or broadening the scope of

  13. Extracting tag hierarchies.

    Science.gov (United States)

    Tibély, Gergely; Pollner, Péter; Vicsek, Tamás; Palla, Gergely

    2013-01-01

    Tagging items with descriptive annotations or keywords is a very natural way to compress and highlight information about the properties of the given entity. Over the years several methods have been proposed for extracting a hierarchy between the tags for systems with a "flat", egalitarian organization of the tags, which is very common when the tags correspond to free words given by numerous independent people. Here we present a complete framework for automated tag hierarchy extraction based on tag occurrence statistics. Along with proposing new algorithms, we are also introducing different quality measures enabling the detailed comparison of competing approaches from different aspects. Furthermore, we set up a synthetic, computer generated benchmark providing a versatile tool for testing, with a couple of tunable parameters capable of generating a wide range of test beds. Beside the computer generated input we also use real data in our studies, including a biological example with a pre-defined hierarchy between the tags. The encouraging similarity between the pre-defined and reconstructed hierarchy, as well as the seemingly meaningful hierarchies obtained for other real systems indicate that tag hierarchy extraction is a very promising direction for further research with a great potential for practical applications. Tags have become very prevalent nowadays in various online platforms ranging from blogs through scientific publications to protein databases. Furthermore, tagging systems dedicated for voluntary tagging of photos, films, books, etc. with free words are also becoming popular. The emerging large collections of tags associated with different objects are often referred to as folksonomies, highlighting their collaborative origin and the "flat" organization of the tags opposed to traditional hierarchical categorization. Adding a tag hierarchy corresponding to a given folksonomy can very effectively help narrowing or broadening the scope of search. Moreover

  14. Extracting Tag Hierarchies

    Science.gov (United States)

    Tibély, Gergely; Pollner, Péter; Vicsek, Tamás; Palla, Gergely

    2013-01-01

    Tagging items with descriptive annotations or keywords is a very natural way to compress and highlight information about the properties of the given entity. Over the years several methods have been proposed for extracting a hierarchy between the tags for systems with a "flat", egalitarian organization of the tags, which is very common when the tags correspond to free words given by numerous independent people. Here we present a complete framework for automated tag hierarchy extraction based on tag occurrence statistics. Along with proposing new algorithms, we are also introducing different quality measures enabling the detailed comparison of competing approaches from different aspects. Furthermore, we set up a synthetic, computer generated benchmark providing a versatile tool for testing, with a couple of tunable parameters capable of generating a wide range of test beds. Beside the computer generated input we also use real data in our studies, including a biological example with a pre-defined hierarchy between the tags. The encouraging similarity between the pre-defined and reconstructed hierarchy, as well as the seemingly meaningful hierarchies obtained for other real systems indicate that tag hierarchy extraction is a very promising direction for further research with a great potential for practical applications. Tags have become very prevalent nowadays in various online platforms ranging from blogs through scientific publications to protein databases. Furthermore, tagging systems dedicated for voluntary tagging of photos, films, books, etc. with free words are also becoming popular. The emerging large collections of tags associated with different objects are often referred to as folksonomies, highlighting their collaborative origin and the “flat” organization of the tags opposed to traditional hierarchical categorization. Adding a tag hierarchy corresponding to a given folksonomy can very effectively help narrowing or broadening the scope of search

  15. 可伸缩TAGS%Scalable TAGS

    Institute of Scientific and Technical Information of China (English)

    闵帆; 张君雁; 杨国纬

    2003-01-01

    In a distributed Web server system where tasks are unpreemptible,the most important issue for improving quality of service (QoS) is how to realize fairness and reduce average slow down. In this paper we present an algorithm named Scalable TAGS by integrating Central Queue algorithm and Task Assignment by Guessing Size (TAGS), together with its performance analysis, system parameter setting algorithm subject to fairness requirement, and optimal grouping method.

  16. Validation and application of Acoustic Mapping Velocimetry

    Science.gov (United States)

    Baranya, Sandor; Muste, Marian

    2016-04-01

    The goal of this paper is to introduce a novel methodology to estimate bedload transport in rivers based on an improved bedform tracking procedure. The measurement technique combines components and processing protocols from two contemporary nonintrusive instruments: acoustic and image-based. The bedform mapping is conducted with acoustic surveys while the estimation of the velocity of the bedforms is obtained with processing techniques pertaining to image-based velocimetry. The technique is therefore called Acoustic Mapping Velocimetry (AMV). The implementation of this technique produces a whole-field velocity map associated with the multi-directional bedform movement. Based on the calculated two-dimensional bedform migration velocity field, the bedload transport estimation is done using the Exner equation. A proof-of-concept experiment was performed to validate the AMV based bedload estimation in a laboratory flume at IIHR-Hydroscience & Engineering (IIHR). The bedform migration was analysed at three different flow discharges. Repeated bed geometry mapping, using a multiple transducer array (MTA), provided acoustic maps, which were post-processed with a particle image velocimetry (PIV) method. Bedload transport rates were calculated along longitudinal sections using the streamwise components of the bedform velocity vectors and the measured bedform heights. The bulk transport rates were compared with the results from concurrent direct physical samplings and acceptable agreement was found. As a first field implementation of the AMV an attempt was made to estimate bedload transport for a section of the Ohio river in the United States, where bed geometry maps, resulted by repeated multibeam echo sounder (MBES) surveys, served as input data. Cross-sectional distributions of bedload transport rates from the AMV based method were compared with the ones obtained from another non-intrusive technique (due to the lack of direct samplings), ISSDOTv2, developed by the US Army

  17. Particle image velocimetry a practical guide

    CERN Document Server

    Raffel, Marcus; Wereley, Steve T; Kompenhans, Jürgen

    2007-01-01

    The development of Particle Image Velocimetry (PIV), a measurement technique, which allows for capturing velocity information of whole ?ow ?elds in fractions of a second, has begun in the eighties of the last century. In 1998, when this book has been published ?rstly, the PIV technique emerged from laboratories to applications in fundamental and industrial research, in par- lel to the transition from photo-graphicalto video recording techniques. Thus this book, whose objective was and is to serve as a practical guide to the PIV technique, found strong interest within the increasing group of us

  18. Extracting tag hierarchies

    CERN Document Server

    Tibély, Gergely; Vicsek, Tamás; Palla, Gergely

    2014-01-01

    Tagging items with descriptive annotations or keywords is a very natural way to compress and highlight information about the properties of the given entity. Over the years several methods have been proposed for extracting a hierarchy between the tags for systems with a "flat", egalitarian organization of the tags, which is very common when the tags correspond to free words given by numerous independent people. Here we present a complete framework for automated tag hierarchy extraction based on tag occurrence statistics. Along with proposing new algorithms, we are also introducing different quality measures enabling the detailed comparison of competing approaches from different aspects. Furthermore, we set up a synthetic, computer generated benchmark providing a versatile tool for testing, with a couple of tunable parameters capable of generating a wide range of test beds. Beside the computer generated input we also use real data in our studies, including a biological example with a pre-defined hierarchy betwe...

  19. Tagging vs. Controlled Vocabulary

    DEFF Research Database (Denmark)

    Bogers, Toine; Petras, Vivien

    2015-01-01

    elements like core bibliographic data, controlled vocabulary terms, reviews, and tags to the retrieval performance. Our comparison is done using a test collection of over 2 million book records with information elements from Amazon, the British Library, the Library of Congress, and LibraryThing. We find...... that tags and controlled vocabulary terms do not actually outperform each other consistently, but seem to provide complementary contributions: some information needs are best addressed using controlled vocabulary terms whereas other are best addressed using tags....

  20. Externally Dispersed Interferometry for Precision Radial Velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D J; Muterspaugh, M W; Edelstein, J; Lloyd, J; Herter, T; Feuerstein, W M; Muirhead, P; Wishnow, E

    2007-03-27

    Externally Dispersed Interferometry (EDI) is the series combination of a fixed-delay field-widened Michelson interferometer with a dispersive spectrograph. This combination boosts the spectrograph performance for both Doppler velocimetry and high resolution spectroscopy. The interferometer creates a periodic spectral comb that multiplies against the input spectrum to create moire fringes, which are recorded in combination with the regular spectrum. The moire pattern shifts in phase in response to a Doppler shift. Moire patterns are broader than the underlying spectral features and more easily survive spectrograph blurring and common distortions. Thus, the EDI technique allows lower resolution spectrographs having relaxed optical tolerances (and therefore higher throughput) to return high precision velocity measurements, which otherwise would be imprecise for the spectrograph alone.

  1. Objective speckle velocimetry for autonomous vehicle odometry.

    Science.gov (United States)

    Francis, D; Charrett, T O H; Waugh, L; Tatam, R P

    2012-06-01

    Speckle velocimetry is investigated as a means of determining odometry data with potential for application on autonomous robotic vehicles. The technique described here relies on the integration of translation measurements made by normalized cross-correlation of speckle patterns to determine the change in position over time. The use of objective (non-imaged) speckle offers a number of advantages over subjective (imaged) speckle, such as a reduction in the number of optical components, reduced modulation of speckles at the edges of the image, and improved light efficiency. The influence of the source/detector configuration on the speckle translation to vehicle translation scaling factor for objective speckle is investigated using a computer model and verified experimentally. Experimental measurements are presented at velocities up to 80  mm s(-1) which show accuracy better than 0.4%.

  2. Externally Dispersed Interferometry for Precision Radial Velocimetry

    CERN Document Server

    Erskine, D J; Edelstein, J; Lloyd, J; Herter, T; Feuerstein, W M; Muirhead, P; Wishnow, E

    2007-01-01

    Externally Dispersed Interferometry (EDI) is the series combination of a fixed-delay field-widened Michelson interferometer with a dispersive spectrograph. This combination boosts the spectrograph performance for both Doppler velocimetry and high resolution spectroscopy. The interferometer creates a periodic spectral comb that multiplies against the input spectrum to create moire fringes, which are recorded in combination with the regular spectrum. The moire pattern shifts in phase in response to a Doppler shift. Moire patterns are broader than the underlying spectral features and more easily survive spectrograph blurring and common distortions. Thus, the EDI technique allows lower resolution spectrographs having relaxed optical tolerances (and therefore higher throughput) to return high precision velocity measurements, which otherwise would be imprecise for the spectrograph alone.

  3. Optical Coherence Tomography Velocimetry with Complex Fluids

    Science.gov (United States)

    Malm, A.; Waigh, T. A.; Jaradat, S.; Tomlin, R.

    2015-04-01

    We present recent results obtained with an Optical Coherence Tomography Velocimetry technique. An optical interferometer measures the velocity of a sheared fluid at specific depths of the sample using the coherence length of the light source. The technique allows the dynamics of 3 pico liter volumes to be probed inside opaque complex fluids. In a study of opaque starch suspensions, classical bulk rheology experiments show non-linear shear thickening, whereas observations of the velocity profiles as a function of distance across the gap show Newtonian behavior. The ability of the technique to measure velocity fluctuations is also discussed for the case of polyacrylamide samples which were observed to display shear banding behavior. A relationship between the viscoelasticity of the sample and the size of the apparent fluctuations is observed.

  4. HTML Tags as Extraction Cues for Web Page Description Construction

    Directory of Open Access Journals (Sweden)

    Timothy C. Craven

    2003-01-01

    Full Text Available Using four previously identified samples of Web pages containing meta-tagged descriptions, the value of meta-tagged keywords, the first 200 characters of the body, and text marked with common HTML tags as extracts helpful for writing summaries was estimated by applying two measures: density of description words and density of two-word description phrases. Generally, titles and keywords showed the highest densities. Parts of the body showed densities not much different from the body as a whole: somewhat higher for the first 200 characters and for text tagged with "center" and "font"; somewhat lower for text tagged with "a"; not significantly different for "table" and "div". Evidence of non-random clumping of description words in the body of some pages nevertheless suggests that further pursuit of automatic passage extraction methods from the body may be worthwhile. Implications of the findings for aids to summarization, and specifically the TexNet32 package, are discussed.

  5. Development of molecular based optical techniques for thermometry and velocimetry for fluorocarbon media

    Science.gov (United States)

    Pouya, Shahram; Blanchard, Gary; Koochesfahani, Manoochehr

    2016-11-01

    Fluorocarbon solvents are very stable inert fluids with unique physical properties that make them attractive compounds as refrigerant and several medical applications such as contrast enhanced ultrasound imaging. Since they do not mix with typical organic solvents or water, most luminescent (fluorescent or phosphorescent) probes cannot be used as tracers for optical diagnostic techniques. Perfluoropentane, a compound from this family, is used as a simulant fluid by NASA for two-phase heat transfer/mixing experiments under micro-gravity condition due to its low boiling temperature. Here we study the feasibility of employing non-intrusive optical methods for measurements of temperature and/or velocity within Perfluoropentane as the working fluid. Preliminary results of temperature and velocity measurement using Laser Induced Fluorescence and Molecular Tagging Velocimetry are presented. This work was supported by NASA Grant Number NNX16AD52A.

  6. Selected Applications of Planar Imaging Velocimetry in Combustion Test Facilities

    Science.gov (United States)

    Willert, Christian; Stockhausen, Guido; Voges, Melanie; Klinner, Joachim; Schodl, Richard; Hassa, Christoph; Schürmans, Bruno; Güthe, Felix

    This chapter provides an overview on the application of particle image velocimetry (PIV) and Doppler global velocimetry (DGV) in combustion test facilities that are operated at pressures of up to 10 bar. Emphasis is placed on the experimental aspects of each application rather than the interpretation of the acquired flow-field data because many of the encountered problems and chosen solution strategies are unique to this area of velocimetry application. In particular, imaging configurations, seeding techniques, data-acquisition strategies as well as pre- and postprocessing methodologies are outlined.

  7. Precision of FLEET Velocimetry Using High-speed CMOS Camera Systems

    Science.gov (United States)

    Peters, Christopher J.; Danehy, Paul M.; Bathel, Brett F.; Jiang, Naibo; Calvert, Nathan D.; Miles, Richard B.

    2015-01-01

    Femtosecond laser electronic excitation tagging (FLEET) is an optical measurement technique that permits quantitative velocimetry of unseeded air or nitrogen using a single laser and a single camera. In this paper, we seek to determine the fundamental precision of the FLEET technique using high-speed complementary metal-oxide semiconductor (CMOS) cameras. Also, we compare the performance of several different high-speed CMOS camera systems for acquiring FLEET velocimetry data in air and nitrogen free-jet flows. The precision was defined as the standard deviation of a set of several hundred single-shot velocity measurements. Methods of enhancing the precision of the measurement were explored such as digital binning (similar in concept to on-sensor binning, but done in post-processing), row-wise digital binning of the signal in adjacent pixels and increasing the time delay between successive exposures. These techniques generally improved precision; however, binning provided the greatest improvement to the un-intensified camera systems which had low signal-to-noise ratio. When binning row-wise by 8 pixels (about the thickness of the tagged region) and using an inter-frame delay of 65 micro sec, precisions of 0.5 m/s in air and 0.2 m/s in nitrogen were achieved. The camera comparison included a pco.dimax HD, a LaVision Imager scientific CMOS (sCMOS) and a Photron FASTCAM SA-X2, along with a two-stage LaVision High Speed IRO intensifier. Excluding the LaVision Imager sCMOS, the cameras were tested with and without intensification and with both short and long inter-frame delays. Use of intensification and longer inter-frame delay generally improved precision. Overall, the Photron FASTCAM SA-X2 exhibited the best performance in terms of greatest precision and highest signal-to-noise ratio primarily because it had the largest pixels.

  8. Molecular Tagging Velocimetry Development for In-situ Measurement in High-Temperature Test Facility

    Science.gov (United States)

    Andre, Matthieu A.; Bardet, Philippe M.; Burns, Ross A.; Danehy, Paul M.

    2015-01-01

    The High Temperature Test Facility, HTTF, at Oregon State University (OSU) is an integral-effect test facility designed to model the behavior of a Very High Temperature Gas Reactor (VHTR) during a Depressurized Conduction Cooldown (DCC) event. It also has the ability to conduct limited investigations into the progression of a Pressurized Conduction Cooldown (PCC) event in addition to phenomena occurring during normal operations. Both of these phenomena will be studied with in-situ velocity field measurements. Experimental measurements of velocity are critical to provide proper boundary conditions to validate CFD codes, as well as developing correlations for system level codes, such as RELAP5 (http://www4vip.inl.gov/relap5/). Such data will be the first acquired in the HTTF and will introduce a diagnostic with numerous other applications to the field of nuclear thermal hydraulics. A laser-based optical diagnostic under development at The George Washington University (GWU) is presented; the technique is demonstrated with velocity data obtained in ambient temperature air, and adaptation to high-pressure, high-temperature flow is discussed.

  9. Flavour Tagging at LHCb

    CERN Multimedia

    Grabalosa Gandara, M

    2009-01-01

    To do precise CP violation measurements, the most possible accurate knowledge of the flavour at production of the reconstructed B meson is required. This poster summarizes the flavour tagging performances for the LHCb experiment. We use same side an opposite side algorithms to establish wheter the meson contained a b or a b\\bar quark. The final decision is obtained through a combination of several methods. The use of control channels, decays to a flavour specific final state, will allow to determine the wrong tag fraction \\omega (the probability of a tag to be wrong), which can be used as input for the determination of CKM unitary triangle angles.

  10. The use of external electronic tags on fish: an evaluation of tag retention and tagging effects

    DEFF Research Database (Denmark)

    Jepsen, Niels; Thorstad, Eva B.; Havn, Torgeir

    2015-01-01

    External tagging of fish with electronic tags has been used for decades for a wide range of marine and freshwater species. In the early years of fish telemetry research, it was the most commonly used attachment method, but later internal implants became preferred. Recently, the number of telemetry...... studies using external tagging has increased, especially with the development of archival tags (data storage tags, DSTs), pop-up satellite archival tags (PSATs) and other environment-sensing tags. Scientific evaluations of the tagging method are rather scarce for most species. We identified 89...... growth and survival have also been recorded, but direct mortality caused by external tagging seems rare. Most of the studies reviewed evaluate tag retention, survival, and tissue reactions. There is a general need for more research on the effects of external tagging of fish with electronic tags...

  11. Volumetric particle image velocimetry with a single plenoptic camera

    Science.gov (United States)

    Fahringer, Timothy W.; Lynch, Kyle P.; Thurow, Brian S.

    2015-11-01

    A novel three-dimensional (3D), three-component (3C) particle image velocimetry (PIV) technique based on volume illumination and light field imaging with a single plenoptic camera is described. A plenoptic camera uses a densely packed microlens array mounted near a high resolution image sensor to sample the spatial and angular distribution of light collected by the camera. The multiplicative algebraic reconstruction technique (MART) computed tomography algorithm is used to reconstruct a volumetric intensity field from individual snapshots and a cross-correlation algorithm is used to estimate the velocity field from a pair of reconstructed particle volumes. This work provides an introduction to the basic concepts of light field imaging with a plenoptic camera and describes the unique implementation of MART in the context of plenoptic image data for 3D/3C PIV measurements. Simulations of a plenoptic camera using geometric optics are used to generate synthetic plenoptic particle images, which are subsequently used to estimate the quality of particle volume reconstructions at various particle number densities. 3D reconstructions using this method produce reconstructed particles that are elongated by a factor of approximately 4 along the optical axis of the camera. A simulated 3D Gaussian vortex is used to test the capability of single camera plenoptic PIV to produce a 3D/3C vector field, where it was found that lateral displacements could be measured to approximately 0.2 voxel accuracy in the lateral direction and 1 voxel in the depth direction over a 300× 200× 200 voxel volume. The feasibility of the technique is demonstrated experimentally using a home-built plenoptic camera based on a 16-megapixel interline CCD camera and a 289× 193 array of microlenses and a pulsed Nd:YAG laser. 3D/3C measurements were performed in the wake of a low Reynolds number circular cylinder and compared with measurements made using a conventional 2D/2C PIV system. Overall, single camera

  12. Ontologies and tag-statistics

    CERN Document Server

    Tibely, Gergely; Vicsek, Tamas; Palla, Gergely

    2012-01-01

    Due to the increasing popularity of collaborative tagging systems, the research on tagged networks, hypergraphs, ontologies, folksonomies and other related concepts is becoming an important interdisciplinary topic with great actuality and relevance for practical applications. In most collaborative tagging systems the tagging by the users is completely "flat", while in some cases they are allowed to define a shallow hierarchy for their own tags. However, usually no overall hierarchical organisation of the tags is given, and one of the interesting challenges of this area is to provide an algorithm generating the ontology of the tags from the available data. In contrast, there are also other type of tagged networks available for research, where the tags are already organised into a directed acyclic graph (DAG), encapsulating the "is a sub-category of" type of hierarchy between each other. In this paper we study how this DAG affects the statistical distribution of tags on the nodes marked by the tags in various r...

  13. TAG Advertisement Hardware

    Science.gov (United States)

    1994-01-01

    LaRc SI Material Overall photograph showing the material specimens, the graphite composite, the gold composite and the molded gears on a black background. These photos were used for the TAG CO-OP Public Relations and promotions

  14. Tagged Vector Contour (TVC)

    Data.gov (United States)

    Kansas Data Access and Support Center — The Kansas Tagged Vector Contour (TVC) dataset consists of digitized contours from the 7.5 minute topographic quadrangle maps. Coverage for the state is incomplete....

  15. b Tagging in CMS

    CERN Document Server

    Tomalin, Ian R

    2008-01-01

    Many of the exotic particles expected at the LHC, such as SUSY, Higgs bosons and top quarks, will decay to b quarks. This paper presents the methods used to identify b-jets at CMS. The algorithms exploit the long B hadron lifetime, semi-leptonic B decays and jet kinematics. The prospect for measuring the performance of these b-tags directly from CMS data is examined. Finally, the use of b-tagging in the High-Level Trigger is explained.

  16. Ultrasound image velocimetry for rheological measurements

    Science.gov (United States)

    Gurung, A.; Haverkort, J. W.; Drost, S.; Norder, B.; Westerweel, J.; Poelma, C.

    2016-09-01

    Ultrasound image velocimetry (UIV) allows for the non-intrusive measurement of a wide range of flows without the need for optical transparency. In this study, we used UIV to measure the local velocity field of a model drilling fluid that exhibits yield stress flow behavior. The radial velocity profile was used to determine the yield stress and the Herschel-Bulkley model flow index n and the consistency index k. Reference data were obtained using the conventional offline Couette rheometry. A comparison showed reasonable agreement between the two methods. The discrepancy in model parameters could be attributed to inherent differences between the methods, which cannot be captured by the three-parameter model used. Overall, with a whole flow field measurement technique such as UIV, we were able to quantify the complex rheology of a model drilling fluid. These preliminary results show that UIV can be used as a non-intrusive diagnostic for in situ, real-time measurement of complex opaque flow rheology.

  17. Facets: Ersatz, Resource and Tag

    Science.gov (United States)

    Frické, Martin H.

    2013-01-01

    Introduction: Faceted classification appears to be of utmost importance. Ersatz facets, resource faceting and tag faceting: The distinctions are drawn between facets and ersatz facets, and between faceted resources and faceted tags. Single tag resource faceting and multiple tag information object faceting: The basic features are explored of single…

  18. 社会化标签系统中基于密度聚类的Web 用户兴趣建模方法%An Approach to Web User Interest Modeling Based on Density-based Clustering Algorithm in the Social Tag System

    Institute of Scientific and Technical Information of China (English)

    易明; 操玉杰; 沈劲枝; 毛进

    2011-01-01

    A Web user' s interest model plays a very important role in the personalized information service. Using the tag ' s unique advantage , this paper proposes an approach of the Web user interest modeling based on density-based clustering algorithm against the limitations of the traditional tag clustering methods. Firstly, a vector space model based on the tags is established, and the tags are described in the form of web resources and their weights, which can be used to cluster the tags based on the DBSCAN algorithm. Then each clustering is viewed as an intermediary to account the special Web user' s interest for the Web resource, according to the tagging behavior of all Web users. The experimental results indicate the superiority of this approach.%Web用户兴趣模型在个性化信息服务中有着非常重要的作用.本文利用社会化标签的独特优势,针对传统社会化标签聚类方法的局限性,提出了一种基于密度聚类的Web用户兴趣建模方法.首先建立基于社会化标签的向量空间模型,并将社会化标签表示为Web资源及其权重的形式,以此为基础利用DBSCAN算法对其进行聚类,进而依据所有Web用户的标注行为以每个聚类为中介计算特定Web用户对Web资源的兴趣度来构建Web用户兴趣模型.实验结果表明了该方法的优越性.

  19. Particle Image Velocimetry and Computational Fluid Dynamics Analysis of Fuel Cell Manifold

    DEFF Research Database (Denmark)

    Lebæk, Jesper; Blazniak Andreasen, Marcin; Andresen, Henrik Assenholm

    2010-01-01

    The inlet effect on the manifold flow in a fuel cell stack was investigated by means of numerical methods (computational fluid dynamics) and experimental methods (particle image velocimetry). At a simulated high current density situation the flow field was mapped on a 70 cell simulated cathode...... manifold. Three different inlet configurations were tested: plug flow, circular inlet, and a diffuser inlet. A very distinct jet was formed in the manifold, when using the circular inlet configuration, which was confirmed both experimentally and numerically. This jet was found to be an asymmetric confined...

  20. Particle tagging and its implications for stellar population dynamics

    CERN Document Server

    Bret, Theo Le; Cooper, Andrew P; Frenk, Carlos; Zolotov, Adi; Brooks, Alyson M; Governato, Fabio; Parry, Owen H

    2015-01-01

    We establish a controlled comparison between the properties of galactic stellar halos obtained with hydrodynamical simulations and with `particle tagging'. Tagging is a fast way to obtain stellar population dynamics: instead of tracking gas and star formation, it `paints' stars directly onto a suitably defined subset of dark matter particles in a collisionless, dark-matter-only simulation.Our study shows that there are conditions under which particle tagging generates good fits to the hydrodynamical stellar density profiles of a central Milky-Way-like galaxy and its most prominent substructure. Phase-space diffusion processes are crucial to reshaping the distribution of stars in infalling spheroidal systems and hence the final stellar halo. We conclude that the success of any particular tagging scheme hinges on this diffusion being taken into account, at a minimum by making use of `live' tagging schemes, in which particles are regularly tagged throughout the evolution of a galaxy.

  1. Stereo-particle image velocimetry uncertainty quantification

    Science.gov (United States)

    Bhattacharya, Sayantan; Charonko, John J.; Vlachos, Pavlos P.

    2017-01-01

    Particle image velocimetry (PIV) measurements are subject to multiple elemental error sources and thus estimating overall measurement uncertainty is challenging. Recent advances have led to a posteriori uncertainty estimation methods for planar two-component PIV. However, no complete methodology exists for uncertainty quantification in stereo PIV. In the current work, a comprehensive framework is presented to quantify the uncertainty stemming from stereo registration error and combine it with the underlying planar velocity uncertainties. The disparity in particle locations of the dewarped images is used to estimate the positional uncertainty of the world coordinate system, which is then propagated to the uncertainty in the calibration mapping function coefficients. Next, the calibration uncertainty is combined with the planar uncertainty fields of the individual cameras through an uncertainty propagation equation and uncertainty estimates are obtained for all three velocity components. The methodology was tested with synthetic stereo PIV data for different light sheet thicknesses, with and without registration error, and also validated with an experimental vortex ring case from 2014 PIV challenge. Thorough sensitivity analysis was performed to assess the relative impact of the various parameters to the overall uncertainty. The results suggest that in absence of any disparity, the stereo PIV uncertainty prediction method is more sensitive to the planar uncertainty estimates than to the angle uncertainty, although the latter is not negligible for non-zero disparity. Overall the presented uncertainty quantification framework showed excellent agreement between the error and uncertainty RMS values for both the synthetic and the experimental data and demonstrated reliable uncertainty prediction coverage. This stereo PIV uncertainty quantification framework provides the first comprehensive treatment on the subject and potentially lays foundations applicable to volumetric

  2. Inclusive Flavour Tagging Algorithm

    Science.gov (United States)

    Likhomanenko, Tatiana; Derkach, Denis; Rogozhnikov, Alex

    2016-10-01

    Identifying the flavour of neutral B mesons production is one of the most important components needed in the study of time-dependent CP violation. The harsh environment of the Large Hadron Collider makes it particularly hard to succeed in this task. We present an inclusive flavour-tagging algorithm as an upgrade of the algorithms currently used by the LHCb experiment. Specifically, a probabilistic model which efficiently combines information from reconstructed vertices and tracks using machine learning is proposed. The algorithm does not use information about underlying physics process. It reduces the dependence on the performance of lower level identification capacities and thus increases the overall performance. The proposed inclusive flavour-tagging algorithm is applicable to tag the flavour of B mesons in any proton-proton experiment.

  3. Tagging behaviour with support from controlled vocabulary

    DEFF Research Database (Denmark)

    Lykke, Marianne; Høj, Anne Lyhne; Madsen, Line Nørgaard

    2011-01-01

    The paper investigates how knowledge structures from a controlled vocabulary affect tagging. The study is a comparative analysis of tags assigned in two tagging systems, a simple tagging system (control system) that provides suggestions from two tag clouds (all users tags and my tags) and an enha...

  4. Helium-filled soap bubbles for vortex core velocimetry

    Science.gov (United States)

    Caridi, Giuseppe Carlo Alp; Sciacchitano, Andrea; Scarano, Fulvio

    2017-09-01

    Velocity measurements within the core of high-swirl vortices are often hampered by heavier-than-air particle tracers being centrifuged outside the vortex core region. The use of neutrally buoyant and lighter-than-air tracers is investigated to aim at homogeneous tracers concentration in air flow experiments dealing with high-swirl vortices using particle image velocimetry. Helium-filled soap bubbles (HFSB) of sub-millimeter diameter are employed as flow tracers. Their density is controlled varying the relative amount of helium and soap solution composing the bubbles. The dynamics of HFSB and micro-size droplets is modeled within a Lamb-Oseen vortex to retrieve the order of magnitude of the tracers slip velocity. A positive radial drift for heavier-than-air tracers leads to an empty vortex core. In contrast, the concentration at the vortex axis is expected to increase for lighter than air tracers. Experiments are conducted on a sharp-edged slender delta wing at 20° incidence. At chosen chord-based Reynolds numbers of 2 × 105 and 6 × 105, a stable laminar vortex is formed above the delta wing. Laser sheet visualization is used to inspect the spatial concentration of tracers. A comparison is made between micron-sized fog droplets and HFSB tracers in the nearly neutrally buoyant condition. Stereo-PIV measurements with fog droplets return a systematically underestimated axial velocity distribution within the vortex core due to drop-out of image cross-correlation signal. The nearly neutrally buoyant HFSB tracers appear to maintain a homogeneous spatial concentration and yield cross-correlation signal up to the vortex axis. The resulting velocity measurements are in good agreement with literature data.

  5. Personalization of tagging systems

    NARCIS (Netherlands)

    Wang, J.; Clements, M.; Yang, J.; Vries, A.P. de; Reinders, M.J.T.

    2010-01-01

    Social media systems have encouraged end user participation in the Internet, for the purpose of storing and distributing Internet content, sharing opinions and maintaining relationships. Collaborative tagging allows users to annotate the resulting user-generated content, and enables effective retrie

  6. Tagging the Teleman Corpus

    CERN Document Server

    Brants, T; Brants, Thorsten; Samuelsson, Christer

    1995-01-01

    Experiments were carried out comparing the Swedish Teleman and the English Susanne corpora using an HMM-based and a novel reductionistic statistical part-of-speech tagger. They indicate that tagging the Teleman corpus is the more difficult task, and that the performance of the two different taggers is comparable.

  7. Tagging Grammatical Functions

    CERN Document Server

    Brants, T; Krenn, B; Brants, Thorsten; Skut, Wojciech; Krenn, Brigitte

    1997-01-01

    This paper addresses issues in automated treebank construction. We show how standard part-of-speech tagging techniques extend to the more general problem of structural annotation, especially for determining grammatical functions and syntactic categories. Annotation is viewed as an interactive process where manual and automatic processing alternate. Efficiency and accuracy results are presented. We also discuss further automation steps.

  8. LHCb flavour tagging performance

    CERN Document Server

    Calvi, M; Musy, M

    2003-01-01

    In CP violation measurements, the most accurate determination of the B flavour of neutral and charged B-mesons is necessary. In this note we summarize the tagging performances for the LHCb experiment, using different approaches and studying different decay channels.

  9. Ontologies and tag-statistics

    Science.gov (United States)

    Tibély, Gergely; Pollner, Péter; Vicsek, Tamás; Palla, Gergely

    2012-05-01

    Due to the increasing popularity of collaborative tagging systems, the research on tagged networks, hypergraphs, ontologies, folksonomies and other related concepts is becoming an important interdisciplinary area with great potential and relevance for practical applications. In most collaborative tagging systems the tagging by the users is completely ‘flat’, while in some cases they are allowed to define a shallow hierarchy for their own tags. However, usually no overall hierarchical organization of the tags is given, and one of the interesting challenges of this area is to provide an algorithm generating the ontology of the tags from the available data. In contrast, there are also other types of tagged networks available for research, where the tags are already organized into a directed acyclic graph (DAG), encapsulating the ‘is a sub-category of’ type of hierarchy between each other. In this paper, we study how this DAG affects the statistical distribution of tags on the nodes marked by the tags in various real networks. The motivation for this research was the fact that understanding the tagging based on a known hierarchy can help in revealing the hidden hierarchy of tags in collaborative tagging systems. We analyse the relation between the tag-frequency and the position of the tag in the DAG in two large sub-networks of the English Wikipedia and a protein-protein interaction network. We also study the tag co-occurrence statistics by introducing a two-dimensional (2D) tag-distance distribution preserving both the difference in the levels and the absolute distance in the DAG for the co-occurring pairs of tags. Our most interesting finding is that the local relevance of tags in the DAG (i.e. their rank or significance as characterized by, e.g., the length of the branches starting from them) is much more important than their global distance from the root. Furthermore, we also introduce a simple tagging model based on random walks on the DAG, capable of

  10. Multiplexed photonic Doppler velocimetry for large channel count experiments

    Science.gov (United States)

    Daykin, Edward; Burk, Martin; Holtkamp, David; Miller, Edward Kirk; Rutkowski, Araceli; Strand, Oliver Ted; Pena, Michael; Perez, Carlos; Gallegos, Cenobio

    2017-01-01

    Photonic Doppler Velocimetry (PDV) is routinely employed as a means of measuring surface velocities for shockwave experimentation. Scientists typically collect ˜4 to 12 channels of PDV data and use extrapolation, assumptions, and models to determine the velocities in regions of the experiment that were not observed directly. We have designed, built and applied a new optical velocimetry diagnostic—the Multiplexed Photonic Doppler Velocimeter (MPDV)—for use on shock physics experiments that require a large number (100s) of spatial points to be measured. MPDV expands upon PDV measurement capabilities via frequency and time multiplexing using commercially available products developed for the telecommunications industry. The MPDV uses the heterodyne method to multiplex four data channels in the frequency domain combined with fiber delays to multiplex an additional four-channel dataset in the time domain, all of which are recorded onto the same digitizer input. This means that each digitizer input records data from eight separate spatial points, so that a single 4-input digitizer may record a total of 32 channels of data. Motivation for development of a multiplexed PDV was driven by requirements for an economical, high-fidelity, high channel-count optical velocimetry system. We present a survey of the methods, components, and trade-offs incorporated into this recent development in optical velocimetry.

  11. Laser Doppler velocimetry in Microchannels using integrated optical waveguides.

    NARCIS (Netherlands)

    Pandraud, G.; van den Berg, Albert; Semenov, S.N.

    2000-01-01

    The possibility of laser Doppler velocimetry (LDV) in microchannels, where particles are suspended in a liquid, and where oscillating or evanescent guided coherent light wave is present, is examined theoretically. The conditions for the observation of the transverse and longitudinal collective phore

  12. Reusable holographic velocimetry system based on polarization multiplexing in Bacteriorhodopsin

    NARCIS (Netherlands)

    Koek, W.D.; Chan, V.S.S.; Ooms, T.A.; Bhattacharya, N.; Westerweel, J.; Braat, J.J.M.

    2005-01-01

    We present a novel holographic particle image velocimetry (HPIV) system using a reversible holographic material as the recording medium. In HPIV the three-dimensional flow field throughout a volume is detected by adding small tracer particles to a normally transparent medium. By recording the

  13. 3D particle tracking velocimetry using dynamic discrete tomography

    NARCIS (Netherlands)

    Alpers, A.; Gritzmann, P.; Moseev, D.; Salewski, M.

    2015-01-01

    Particle tracking velocimetry in 3D is becoming an increasingly important imaging tool in the study of fluid dynamics and combustion as well as plasmas. We introduce a dynamic discrete tomography algorithm for reconstructing particle trajectories from projections. The algorithm is efficient for data

  14. Advances in Time-Resolved Tomographic Particle Image Velocimetry

    NARCIS (Netherlands)

    Lynch, K.P.

    2015-01-01

    This thesis details advanced developments in 3-D particle image velocimetry (PIV) based on the tomographic PIV technique, with an emphasis on time-resolved experiments. Tomographic PIV is a technique introduced in 2006 to measure the flow velocity in a three-dimensional volume. When measurements are

  15. Counter Rotating Open Rotor Animation using Particle Image Velocimetry

    CERN Document Server

    Roosenboom, E W M; Geisler, R; Pallek, D; Agocs, J; Neitzke, K -P

    2011-01-01

    This article describes the two accompanying fluid dynamics videos for the "Counter rotating open rotor flow field investigation using stereoscopic Particle Image Velocimetry" presented at the 64th Annual Meeting of the APS Division of Fluid Dynamics in Baltimore, Maryland, November 20-22, 2011.

  16. 3D particle tracking velocimetry using dynamic discrete tomography

    DEFF Research Database (Denmark)

    Alpers, Andreas; Gritzmann, Peter; Moseev, Dmitry;

    2015-01-01

    Particle tracking velocimetry in 3D is becoming an increasingly important imaging tool in the study of fluid dynamics and combustion as well as plasmas. We introduce a dynamic discrete tomography algorithm for reconstructing particle trajectories from projections. The algorithm is efficient...

  17. Coherent optical transients observed in rubidium atomic line filtered Doppler velocimetry experiments

    Energy Technology Data Exchange (ETDEWEB)

    Fajardo, Mario E., E-mail: mario.fajardo@eglin.af.mil; Molek, Christopher D.; Vesely, Annamaria L. [Air Force Research Laboratory, Munitions Directorate, Ordnance Division, Energetic Materials Branch, AFRL/RWME, 2306 Perimeter Road, Eglin AFB, Florida 32542-5910 (United States)

    2015-10-14

    We report the first successful results from our novel Rubidium Atomic Line Filtered (RALF) Doppler velocimetry apparatus, along with unanticipated oscillatory signals due to coherent optical transients generated within pure Rb vapor cells. RALF is a high-velocity and high-acceleration extension of the well-known Doppler Global Velocimetry (DGV) technique for constructing multi-dimensional flow velocity vector maps in aerodynamics experiments [H. Komine, U.S. Patent No. 4,919,536 (24 April 1990)]. RALF exploits the frequency dependence of pressure-broadened Rb atom optical absorptions in a heated Rb/N{sub 2} gas cell to encode the Doppler shift of reflected near-resonant (λ{sub 0} ≈ 780.24 nm) laser light onto the intensity transmitted by the cell. The present RALF apparatus combines fiber optic and free-space components and was built to determine suitable operating conditions and performance parameters for the Rb/N{sub 2} gas cells. It yields single-spot velocities of thin laser-driven-flyer test surfaces and incorporates a simultaneous Photonic Doppler Velocimetry (PDV) channel [Strand et al., Rev. Sci. Instrum. 77, 083108 (2006)] for validation of the RALF results, which we demonstrate here over the v = 0 to 1 km/s range. Both RALF and DGV presume the vapor cells to be simple Beer's Law optical absorbers, so we were quite surprised to observe oscillatory signals in experiments employing low pressure pure Rb vapor cells. We interpret these oscillations as interference between the Doppler shifted reflected light and the Free Induction Decay (FID) coherent optical transient produced within the pure Rb cells at the original laser frequency; this is confirmed by direct comparison of the PDV and FID signals. We attribute the different behaviors of the Rb/N{sub 2} vs. Rb gas cells to efficient dephasing of the atomic/optical coherences by Rb-N{sub 2} collisions. The minimum necessary N{sub 2} buffer gas density ≈0.3 amagat translates into a

  18. Tag-elese or The Language of Tags

    Directory of Open Access Journals (Sweden)

    Jan Simons

    2008-01-01

    Full Text Available The core "meme" of Web 2.0 from which almost all other memes radiated was: 'You control your own data' (O'Reilly, 2005, 3. Key instruments for this user control are tagging systems that allow users to freely assign keywords of their own choosing to Internet resources of their own making as well as to documents produced by others. Of course, freely chosen keywords tags do not necessarily follow prefixed taxonomies or classification systems. But going by the maxim that interaction creates similarity and similarity creates interaction, the idea - or hope - is, however, that the tagging practices of individual users will eventually converge into an emergent common vocabulary or folksonomy (Merholz, 2004; Shirky, 2005; Vander Wal, 2005b; Mika, 2007. It is far from clear, however, that free tagging systems will eventually yield controlled vocabularies, and there are many incentives for idiosyncratic, ambiguous, and inconsistent uses of tags. Left to themselves, free tagging systems seem to be too wild and too chaotic for any order to emerge. But are these free tagging systems really as "feral" as they seem to be, or do they only look uncontrolled because one has been looking for order in the wrong place? I have done a quick-and-dirty" analysis of Flickr's tag cloud. The concept was: if folksonomies encourage users to tap on their own vernacular, everyday natural language must somehow "guide" the tagging practices of users of tagging systems. Flickr's tag cloud has been choosen because it may teach us something about tagging systems and folksonomies, and not - or not primarily - because of what tags may tell us about pictures.

  19. Study of mast cell count in skin tags

    Directory of Open Access Journals (Sweden)

    Zaher Hesham

    2007-01-01

    Full Text Available Background: Skin tags or acrochordons are common tumors of middle-aged and elderly subjects. They consist of loose fibrous tissue and occur mainly on the neck and major flexures as small, soft, pedunculated protrusions. Objectives: The aim was to compare the mast cells count in skin tags to adjacent normal skin in diabetic and nondiabetic participants in an attempt to elucidate the possible role of mast cells in the pathogenesis of skin tags. Participants and Methods: Thirty participants with skin tags were divided into group I (15 nondiabetic participants and group II (15 diabetic participants. Three biopsies were obtained from each participant: a large skin tag, a small skin tag and adjacent normal skin. Mast cell count from all the obtained sections was carried out, and the mast cell density was expressed as the average mast cell count/high power field (HPF. Results: A statistically significant increase in mast cells count in skin tags in comparison to normal skin was detected in group I and group II. There was no statistically significant difference between mast cell counts in skin tags of both the groups. Conclusion: Both the mast cell mediators and hyperinsulinemia are capable of inducing fibroblast proliferation and epidermal hyperplasia that are the main pathologic abnormalities seen in all types of skin tags. However, the presence of mast cells in all examined skin tags regardless of diabetes and obesity may point to the possible crucial role of mast cells in the etiogenesis of skin tags through its interaction with fibroblasts and keratinocytes.

  20. From the track to the ocean: Using flow control to improve marine bio-logging tags for cetaceans.

    Science.gov (United States)

    Fiore, Giovani; Anderson, Erik; Garborg, C Spencer; Murray, Mark; Johnson, Mark; Moore, Michael J; Howle, Laurens; Shorter, K Alex

    2017-01-01

    Bio-logging tags are an important tool for the study of cetaceans, but superficial tags inevitably increase hydrodynamic loading. Substantial forces can be generated by tags on fast-swimming animals, potentially affecting behavior and energetics or promoting early tag removal. Streamlined forms have been used to reduce loading, but these designs can accelerate flow over the top of the tag. This non-axisymmetric flow results in large lift forces (normal to the animal) that become the dominant force component at high speeds. In order to reduce lift and minimize total hydrodynamic loading this work presents a new tag design (Model A) that incorporates a hydrodynamic body, a channel to reduce fluid speed differences above and below the housing and wing to redirect flow to counter lift. Additionally, three derivatives of the Model A design were used to examine the contribution of individual flow control features to overall performance. Hydrodynamic loadings of four models were compared using computational fluid dynamics (CFD). The Model A design eliminated all lift force and generated up to ~30 N of downward force in simulated 6 m/s aligned flow. The simulations were validated using particle image velocimetry (PIV) to experimentally characterize the flow around the tag design. The results of these experiments confirm the trends predicted by the simulations and demonstrate the potential benefit of flow control elements for the reduction of tag induced forces on the animal.

  1. From the track to the ocean: Using flow control to improve marine bio-logging tags for cetaceans

    Science.gov (United States)

    Fiore, Giovani; Anderson, Erik; Garborg, C. Spencer; Murray, Mark; Johnson, Mark; Moore, Michael J.; Howle, Laurens

    2017-01-01

    Bio-logging tags are an important tool for the study of cetaceans, but superficial tags inevitably increase hydrodynamic loading. Substantial forces can be generated by tags on fast-swimming animals, potentially affecting behavior and energetics or promoting early tag removal. Streamlined forms have been used to reduce loading, but these designs can accelerate flow over the top of the tag. This non-axisymmetric flow results in large lift forces (normal to the animal) that become the dominant force component at high speeds. In order to reduce lift and minimize total hydrodynamic loading this work presents a new tag design (Model A) that incorporates a hydrodynamic body, a channel to reduce fluid speed differences above and below the housing and wing to redirect flow to counter lift. Additionally, three derivatives of the Model A design were used to examine the contribution of individual flow control features to overall performance. Hydrodynamic loadings of four models were compared using computational fluid dynamics (CFD). The Model A design eliminated all lift force and generated up to ~30 N of downward force in simulated 6 m/s aligned flow. The simulations were validated using particle image velocimetry (PIV) to experimentally characterize the flow around the tag design. The results of these experiments confirm the trends predicted by the simulations and demonstrate the potential benefit of flow control elements for the reduction of tag induced forces on the animal. PMID:28196148

  2. Upper Tag Ontology (UTO) For Integrating Social Tagging Data

    CERN Document Server

    Ding, Ying; Fried, Michael; Toma, Ioan; Yan, Erjia; Foo, Schubert

    2010-01-01

    Data integration and mediation have become central concerns of information technology over the past few decades. With the advent of the Web and the rapid increases in the amount of data and the number of Web documents and users, researchers have focused on enhancing the interoperability of data through the development of metadata schemes. Other researchers have looked to the wealth of metadata generated by bookmarking sites on the Social Web. While several existing ontologies capitalize on the semantics of metadata created by tagging activities, the Upper Tag Ontology (UTO) emphasizes the structure of tagging activities to facilitate modeling of tagging data and the integration of data from different bookmarking sites as well as the alignment of tagging ontologies. UTO is described and its utility in harvesting, modeling, integrating, searching and analyzing data is demonstrated with metadata harvested from three major social tagging systems (Delicious, Flickr and YouTube).

  3. Social Tagging of Mission Data

    Science.gov (United States)

    Norris, Jeffrey S.; Wallick, Michael N.; Joswig, Joseph C.; Powell, Mark W.; Torres, Recaredo J.; Mittman, David S.; Abramyan, Lucy; Crockett, Thomas M.; Shams, Khawaja S.; Fox, Jason M.; Pyrzak, Guy; Vaughn, Michael B.

    2010-01-01

    Mars missions will generate a large amount of data in various forms, such as daily plans, images, and scientific information. Often, there is a semantic linkage between images that cannot be captured automatically. Software is needed that will provide a method for creating arbitrary tags for this mission data so that items with a similar tag can be related to each other. The tags should be visible and searchable for all users. A new routine was written to offer a new and more flexible search option over previous applications. This software allows users of the MSLICE program to apply any number of arbitrary tags to a piece of mission data through a MSLICE search interface. The application of tags creates relationships between data that did not previously exist. These tags can be easily removed and changed, and contain enough flexibility to be specifically configured for any mission. This gives users the ability to quickly recall or draw attention to particular pieces of mission data, for example: Give a semantic and meaningful description to mission data; for example, tag all images with a rock in them with the tag "rock." Rapidly recall specific and useful pieces of data; for example, tag a plan as"driving template." Call specific data to a user s attention; for example, tag a plan as "for:User." This software is part of the MSLICE release, which was written in Java. It will run on any current Windows, Macintosh, or Linux system.

  4. Towards an "Intelligent" Tagging Tool for Blogs

    Science.gov (United States)

    Frank, Juraj; Motschnig, Renate; Homola, Martin

    Tagging allows people to effectively organize web resources such as images, bookmarks or blog articles. Things are found easier by browsing tag clouds relying on the tags that have been assigned before. The success is by large determined by the quality and relevance of tags assigned to content - and so it is dependent on people who do the tagging. We investigate mental processes that underlie tagging. In order to improve quality of tagging, we provide guidelines for users of tagging systems and in addition we suggest features that an "intelligent" tagging tool should bear in order to facilitate the tagging process.

  5. Buddy Tag CONOPS and Requirements.

    Energy Technology Data Exchange (ETDEWEB)

    Brotz, Jay Kristoffer [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Deland, Sharon M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    This document defines the concept of operations (CONOPS) and the requirements for the Buddy Tag, which is conceived and designed in collaboration between Sandia National Laboratories and Princeton University under the Department of State Key VerificationAssets Fund. The CONOPS describe how the tags are used to support verification of treaty limitations and is only defined to the extent necessary to support a tag design. The requirements define the necessary functions and desired non-functional features of the Buddy Tag at a high level

  6. Confocal laser scanning microscopy image correlation for nanoparticle flow velocimetry

    CERN Document Server

    Jun, Brian; Yang, Haisheng; Main, Russell; Vlachos, Pavlos

    2016-01-01

    We present a new particle image correlation technique for resolving nanoparticle flow velocity using confocal laser scanning microscopy (CLSM). The two primary issues that complicate nanoparticle scanning laser image correlation (SLIC) based velocimetry are (1) the use of diffusion dominated nanoparticles as flow tracers, which introduce a random decorrelating error into the velocity estimate, and (2) the effects of the scanning laser image acquisition, which introduces a bias error. To date, no study has quantified these errors or demonstrated a means to deal with them in SLIC velocimetry. In this work, we build upon the robust phase correlation (RPC) and existing methods of SLIC to quantify and mitigate these errors. First, we implement an ensemble RPC instead of using an ensemble standard cross correlation, and develop an SLIC optimal filter that maximizes the correlation strength in order to reliably and accurately detect the correlation peak representing the most probable average displacement of the nano...

  7. Fluorescent angiography of chicken embryo and photobleaching velocimetry

    Science.gov (United States)

    Namykin, Anton A.; Stiukhina, Elena S.; Fedosov, Ivan V.; Postnov, Dmitry E.; Tuchin, Valery V.

    2017-03-01

    Fluorescent angiography approach in application to a living chicken embryo is discussed. It provides precise vessel wall detection and demonstrates usefulness for real time monitoring of vasoconstriction and vasodilatation related to self regulation of vascular network as well as to response to external factors. On the other hand, high stability of fluorescence and long period of dye elimination makes variations of fluorescent intensity practically independent from fast variations of blood flow rate. Therefore, we proposed the improvement of fluorescent angiography technique by introduction of photobleaching fluorescent velocimetry approach. We have developed the imaging system for intravital microscopic photobleaching velocimetry and tested it by using a glass capillary tube as a model of blood vessel. We demonstrated high potential of the technique for instant flow velocity distribution profile measurement with high spatial and temporal resolution up to 2 μm and 60 ms, respectively.

  8. Externally Dispersed Interferometry for Resolution Boosting and Doppler Velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D J

    2003-12-01

    Externally dispersed interferometry (EDI) is a rapidly advancing technique for wide bandwidth spectroscopy and radial velocimetry. By placing a small angle-independent interferometer near the slit of an existing spectrograph system, periodic fiducials are embedded on the recorded spectrum. The multiplication of the stellar spectrum times the sinusoidal fiducial net creates a moire pattern, which manifests high detailed spectral information heterodyned down to low spatial frequencies. The latter can more accurately survive the blurring, distortions and CCD Nyquist limitations of the spectrograph. Hence lower resolution spectrographs can be used to perform high resolution spectroscopy and radial velocimetry (under a Doppler shift the entire moir{acute e} pattern shifts in phase). A demonstration of {approx}2x resolution boosting (100,000 from 50,000) on the Lick Obs. echelle spectrograph is shown. Preliminary data indicating {approx}8x resolution boost (170,000 from 20,000) using multiple delays has been taken on a linear grating spectrograph.

  9. 3D particle tracking velocimetry using dynamic discrete tomography

    CERN Document Server

    Alpers, Andreas; Moseev, Dmitry; Salewski, Mirko

    2013-01-01

    Particle tracking velocimetry in 3D is becoming an increasingly important imaging tool in the study of fluid dynamics, combustion as well as plasmas. We introduce a dynamic discrete tomography algorithm for reconstructing particle trajectories from projections. The algorithm is efficient for data from two projection directions and exact in the sense that it finds a solution consistent with the experimental data. Non-uniqueness of solutions can be detected and solutions can be tracked individually.

  10. Particle tracking velocimetry of a gliding arc discharge

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas;

    2014-01-01

    A 35 kHz AC gliding arc discharge at atmospheric pressure is generated between two diverging electrodes and extended by an air flow. The gas flow velocity is measured by particle tracking velocimetry (PTV) while the moving velocity of the plasma column of the gliding arc discharge is measured...... by analyzing the movie taken by a high-speed camera. The two-dimensional velocity vector of the gas flow and of the gliding arc in the imaging plane was determined....

  11. Optical coherence tomography-based micro-particle image velocimetry.

    Science.gov (United States)

    Mujat, Mircea; Ferguson, R Daniel; Iftimia, Nicusor; Hammer, Daniel X; Nedyalkov, Ivaylo; Wosnik, Martin; Legner, Hartmut

    2013-11-15

    We present a new application of optical coherence tomography (OCT), widely used in biomedical imaging, to flow analysis in near-wall hydrodynamics for marine research. This unique capability, called OCT micro-particle image velocimetry, provides a high-resolution view of microscopic flow phenomena and measurement of flow statistics within the first millimeter of a boundary layer. The technique is demonstrated in a small flow cuvette and in a water tunnel.

  12. 3D particle tracking velocimetry using dynamic discrete tomography

    DEFF Research Database (Denmark)

    Alpers, Andreas; Gritzmann, Peter; Moseev, Dmitry

    2015-01-01

    Particle tracking velocimetry in 3D is becoming an increasingly important imaging tool in the study of fluid dynamics and combustion as well as plasmas. We introduce a dynamic discrete tomography algorithm for reconstructing particle trajectories from projections. The algorithm is efficient...... for data from two projection directions and exact in the sense that it finds a solution consistent with the experimental data. Non-uniqueness of solutions can be detected and solutions can be tracked individually....

  13. Design, construction, alignment, and calibration of a compact velocimetry experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kaufman, Morris I.; Malone, Robert M.; Frogget, Brent C.; Romero, Vincent T.; Esquibel, David L.; Iverson, Adam; Lare, Gregory A.; Briggs, Bart; DeVore, Douglas; Cata, Brian; McGillivray, Kevin; Palagi, Martin; et al.,

    2007-08-31

    A velocimetry experiment has been designed to measure shock properties for small, cylindrical, metal targets (8 mm diameter × 2 mm thick). A target is accelerated by high explosives, caught, then retrieved for later inspection. The target is expected to move at a velocity of 0.1 to 3 km/sec. The complete experiment canister is ~105 mm in diameter and 380 mm long. Optical velocimetry diagnostics include the Velocity Interferometer System for Any Reflector (VISAR) and photon Doppler velocimetry (PDV). The packaging of the velocity diagnostics is not allowed to interfere with the foam catchment or an X-ray imaging diagnostic. Using commercial lenses, a single optical relay collects Doppler-shifted light for both VISAR and PDV. The use of fiber optics allows measurement of point velocities on the target surface for accelerations lasting for 3 mm of travel. Operating at 532 nm, the VISAR has separate illumination fibers requiring alignment. The PDV diagnostic operates at 1550 nm but is aligned and calibrated at 670 nm. VISAR and PDV diagnostics are complimentary measurements that image spots in close proximity on the target surface. Because the optical relay uses commercial glass, optical fibers’ axial positions are offset to compensate for chromatic aberrations. The optomechanical design requires careful attention to fiber management, mechanical assembly and disassembly, foam catchment design, and X-ray diagnostic field of view.Calibration and alignment data are archived at each assembly sequence stage. The photon budgets for the VISAR and PDV diagnostics are separately estimated.

  14. Functionalised alginate flow seeding microparticles for use in Particle Image Velocimetry (PIV).

    Science.gov (United States)

    Varela, Sylvana; Balagué, Isaac; Sancho, Irene; Ertürk, Nihal; Ferrando, Montserrat; Vernet, Anton

    2016-01-01

    Alginate microparticles as flow seeding fulfil all the requirements that are recommended for the velocity measurements in Particle Image Velocimetry (PIV). These spherical microparticles offer the advantage of being environmentally friendly, having excellent seeding properties and they can be produced via a very simple process. In the present study, the performances of alginate microparticles functionalised with a fluorescent dye, Rhodamine B (RhB), for PIV have been studied. The efficacy of fluorescence is appreciated in a number of PIV applications since it can boost the signal-to-noise ratio. Alginate microparticles functionalised with RhB have high emission efficiency, desirable match with fluid density and controlled size. The study of the particles behaviour in strong acid and basic solutions and ammonia is also included. This type of particles can be used for measurements with PIV and Planar Laser Induced Fluorescence (PLIF) simultaneously, including acid-base reactions.

  15. LHCb Tag Collector

    CERN Document Server

    Fuente Fernàndez, P; Cousin, N

    2011-01-01

    The LHCb physics software consists of hundreds of packages, each of which is developed by one or more physicists. When the developers have some code changes that they would like released, they commit them to the version control system, and enter the revision number into a database. These changes have to be integrated into a new release of each of the physics analysis applications. Tests are then performed by a nightly build system, which rebuilds various configurations of the whole software stack and executes a suite of run-time functionality tests. A Tag Collector system has been developed using solid standard technologies to cover both the use cases of developers and integration managers. A simple Web interface, based on an AJAX-like technology, is available. Integration with software management and Nightly Build programs is possible via a Python API. Data are stored in a relational database with the help of an ORM (Object-Relational Mapping) library.

  16. Tag Gardening for Folksonomy Enrichment and Maintenance

    Directory of Open Access Journals (Sweden)

    Katrin Weller

    2008-09-01

    Full Text Available As social tagging applications continuously gain in popularity, it becomes more and more accepted that models and tools for (re-organizing tags are needed. Some first approaches are already practically implemented. Recently, activities to edit and organize tags have been described as "tag gardening". We discuss different ways to subsequently revise and reedit tags and thus introduce different "gardening activities"; among them models that allow gradually adding semantic structures to folksonomies and/or that combine them with more complex forms of knowledge organization systems. Moreover, power tags are introduced as tag gardening candidates and the personal tag repository TagCare is presented.

  17. An Overview of Social Tagging and Applications

    Science.gov (United States)

    Gupta, Manish; Li, Rui; Yin, Zhijun; Han, Jiawei

    Social tagging on online portals has become a trend now. It has emerged as one of the best ways of associating metadata with web objects. With the increase in the kinds of web objects becoming available, collaborative tagging of such objects is also developing along new dimensions. This popularity has led to a vast literature on social tagging. In this survey paper, we would like to summarize different techniques employed to study various aspects of tagging. Broadly, we would discuss about properties of tag streams, tagging models, tag semantics, generating recommendations using tags, visualizations of tags, applications of tags, integration of different tagging systems and problems associated with tagging usage. We would discuss topics like why people tag, what influences the choice of tags, how to model the tagging process, kinds of tags, different power laws observed in tagging domain, how tags are created and how to choose the right tags for recommendation. Metadata generated in the form of tags can be efficiently used to improve web search, for web object classification, for generating ontologies, for enhanced browsing etc. We would discuss these applications and conclude with thoughts on future work in the area.

  18. Engineering the ATLAS TAG Browser

    CERN Document Server

    Zhang, Q; The ATLAS collaboration

    2011-01-01

    ELSSI is a web-based event metadata (TAG) browser and event-level selection service for ATLAS. TAGs from all ATLAS physics and Monte Carlo data sets are routinely loaded into Oracle databases as an integral part of event processing. As data volumes increase, more and more sites are joining the distributed TAG data hosting topology. Meanwhile, TAG content and database schemata continue to evolve as new user requirements and additional sources of metadata emerge. All of this has posed many challenges to the development of ELSSI, which must support vast amounts of TAG data while source, content, geographic locations, and user query patterns may change over time. In this paper, we describe some of the challenges encountered in the process of developing ELSSI, and the software engineering strategies adopted to address those challenges. Approaches to management of access to data, browsing, data rendering, query building, query validation, execution, connection management, and communication with auxiliary services a...

  19. Semiotic dynamics and collaborative tagging.

    Science.gov (United States)

    Cattuto, Ciro; Loreto, Vittorio; Pietronero, Luciano

    2007-01-30

    Collaborative tagging has been quickly gaining ground because of its ability to recruit the activity of web users into effectively organizing and sharing vast amounts of information. Here we collect data from a popular system and investigate the statistical properties of tag cooccurrence. We introduce a stochastic model of user behavior embodying two main aspects of collaborative tagging: (i) a frequency-bias mechanism related to the idea that users are exposed to each other's tagging activity; (ii) a notion of memory, or aging of resources, in the form of a heavy-tailed access to the past state of the system. Remarkably, our simple modeling is able to account quantitatively for the observed experimental features with a surprisingly high accuracy. This points in the direction of a universal behavior of users who, despite the complexity of their own cognitive processes and the uncoordinated and selfish nature of their tagging activity, appear to follow simple activity patterns.

  20. Particle tagging and its implications for stellar population dynamics

    Science.gov (United States)

    Le Bret, Theo; Pontzen, Andrew; Cooper, Andrew P.; Frenk, Carlos; Zolotov, Adi; Brooks, Alyson M.; Governato, Fabio; Parry, Owen H.

    2017-07-01

    We establish a controlled comparison between the properties of galactic stellar haloes obtained with hydrodynamical simulations and with 'particle tagging'. Tagging is a fast way to obtain stellar population dynamics: instead of tracking gas and star formation, it 'paints' stars directly on to a suitably defined subset of dark matter particles in a collisionless, dark-matter-only simulation. Our study shows that 'live' particle tagging schemes, where stellar masses are painted on to the dark matter particles dynamically throughout the simulation, can generate good fits to the hydrodynamical stellar density profiles of a central Milky Way-like galaxy and its most prominent substructure. Energy diffusion processes are crucial to reshaping the distribution of stars in infalling spheroidal systems and hence the final stellar halo. We conclude that the success of any particular tagging scheme hinges on this diffusion being taken into account, and discuss the role of different subgrid feedback prescriptions in driving this diffusion.

  1. Adapted MR velocimetry of slow liquid flow in porous media

    Science.gov (United States)

    Huang, Li; Mikolajczyk, Gerd; Küstermann, Ekkehard; Wilhelm, Michaela; Odenbach, Stefan; Dreher, Wolfgang

    2017-03-01

    MR velocimetry of liquid flow in opaque porous filters may play an important role in better understanding the mechanisms of deep bed filtration. With this knowledge, the efficiency of separating the suspended solid particles from the vertically flowing liquid can be improved, and thus a wide range of industrial applications such as wastewater treatment and desalination can be optimized. However, MR velocimetry is challenging for such studies due to the low velocities, the severe B0 inhomogeneity in porous structures, and the demand for high spatial resolution and an appropriate total measurement time during which the particle deposition will change velocities only marginally. In this work, a modified RARE-based MR velocimetry method is proposed to address these issues for velocity mapping on a deep bed filtration cell. A dedicated RF coil with a high filling factor is constructed considering the limited space available for the vertical cell in a horizontal MR magnet. Several means are applied to optimize the phase contrast RARE MRI pulse sequence for accurately measuring the phase contrast in a long echo train, even in the case of a low B1 homogeneity. Two means are of particular importance. One uses data acquired with zero flow to correct the phase contrast offsets from gradient imperfections, and the other combines the phase contrast from signals of both odd and even echoes. Results obtained on a 7T preclinical MR scanner indicate that the low velocities in the heterogeneous system can be correctly quantified with high spatial resolution and an adequate total measurement time, enabling future studies on flow during the filtration process.

  2. XPIV-Multi-plane stereoscopic particle image velocimetry

    Science.gov (United States)

    Liberzon, A.; Gurka, R.; Hetsroni, G.

    We introduce the three-dimensional measurement technique (XPIV) based on a Particle Image Velocimetry (PIV) system. The technique provides three-dimensional and statistically significant velocity data. The main principle of the technique lies in the combination of defocus, stereoscopic and multi-plane illumination concepts. Preliminary results of the turbulent boundary layer in a flume are presented. The quality of the velocity data is evaluated by using the velocity profiles and relative turbulent intensity of the boundary layer. The analysis indicates that the XPIV is a reliable experimental tool for three-dimensional fluid velocity measurements.

  3. XPIV-Multi-plane stereoscopic particle image velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Liberzon, A. [Multiphase Flow Laboratory, Faculty of Mechanical Engineering, Technion-IIT, 32000, Haifa (Israel); Institute of Hydromechanics and Water Resources Management, ETH, Zurich (Switzerland); Gurka, R. [Multiphase Flow Laboratory, Faculty of Mechanical Engineering, Technion-IIT, 32000, Haifa (Israel); Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD (United States); Hetsroni, G. [Multiphase Flow Laboratory, Faculty of Mechanical Engineering, Technion-IIT, 32000, Haifa (Israel)

    2004-02-01

    We introduce the three-dimensional measurement technique (XPIV) based on a Particle Image Velocimetry (PIV) system. The technique provides three-dimensional and statistically significant velocity data. The main principle of the technique lies in the combination of defocus, stereoscopic and multi-plane illumination concepts. Preliminary results of the turbulent boundary layer in a flume are presented. The quality of the velocity data is evaluated by using the velocity profiles and relative turbulent intensity of the boundary layer. The analysis indicates that the XPIV is a reliable experimental tool for three-dimensional fluid velocity measurements. (orig.)

  4. SIRHEN : a data reduction program for photonic Doppler velocimetry measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Daniel H., III; Ao, Tommy

    2010-06-01

    SIRHEN (Sandia InfraRed HEtrodyne aNalysis) is a program for reducing data from photonic Doppler velocimetry (PDV) measurements. SIRHEN uses the short-time Fourier transform method to extract velocity information. The program can be run in MATLAB (2008b or later) or as a Windows executable. This report describes the new Sandia InfraRed HEtrodyne aNalysis program (SIRHEN; pronounced 'siren') that has been developed for efficient and robust analysis of PDV data. The program was designed for easy use within Sandia's dynamic compression community.

  5. Spatial Spectra of Jet Turbulence Measured by Particle Image Velocimetry

    DEFF Research Database (Denmark)

    Wänström, Maja; George, William K.; Meyer, Knud Erik

    2009-01-01

    The unique capabilities of particle image velocimetry (PIV) have been utilized together with two-point similarity theory to measure spatial spectra in a ‘homogenized’ fully-developed turbulence jet at relatively high Reynolds number (20,000). The theory developed by Ewing et al. [1] was found...... to be in excellent agreement with the data, and in fact key to the present application. Despite relatively poor spatial resolution of the scales of motion (up to 15 times the Kolmogorov microscale) and limited dynamic range due to progressive jet velocity decay, it was possible to produce highly accurate spectra...

  6. Brief review of uncertainty quantification for particle image velocimetry

    Science.gov (United States)

    Farias, M. H.; Teixeira, R. S.; Koiller, J.; Santos, A. M.

    2016-07-01

    Metrological studies for particle image velocimetry (PIV) are recent in literature. An attempt to evaluate the uncertainty quantifications (UQ) of the PIV velocity field are in evidence. Therefore, a short review on main sources of uncertainty in PIV and available methodologies for its quantification are presented. In addition, the potential of some mathematical techniques, coming from the area of geometric mechanics and control, that could interest the fluids UQ community are highlighted as good possibilities. “We must measure what is measurable and make measurable what cannot be measured” (Galileo)

  7. Application of particle image velocimetry to dusty plasma systems

    Science.gov (United States)

    Williams, Jeremiah D.

    2016-06-01

    > Particle image velocimetry is a fluid measurement technique that has been used for more than 20 years to characterize the particle transport and thermal state of dusty plasma systems. This manuscript provides an overview of this diagnostic technique, highlighting the strengths and limitations that are associated with its use. Additionally, the variations of this technique that have been applied in the study of dusty plasma systems will be discussed, along with a small selection of measurements that can be made with the technique. Potential future directions for this diagnostic tool within the dusty plasma community will also be discussed.

  8. RECENT PROGRESS ON PARTICLE IMAGE VELOCIMETRY IN CHINA

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    An up-to-date review of recent progress on Particle Image Velocimetry (PIV) instrumentations was extensively presented in the paper. Around 80 literatures were referenced. Among various aspects of PIV advances, the present concern was mainly placed on progresses of advanced algorithms and microscopic PIV. Attention was specifically directed toward contributions of domestic researchers to these subjects, which were stressed throughout the discussion. In addition, diverse applications of PIV technology in China, e.g., turbulence measurement, hydrodynamics, rotating flows, two-phase flows, were specifically summarized.

  9. Tagging behaviour with support from controlled vocabulary

    DEFF Research Database (Denmark)

    Lykke, Marianne; Høj, Anne Lyhne; Madsen, Line Nørgaard

    2011-01-01

    The paper investigates how knowledge structures from a controlled vocabulary affect tagging. The study is a comparative analysis of tags assigned in two tagging systems, a simple tagging system (control system) that provides suggestions from two tag clouds (all users tags and my tags) and an enha......The paper investigates how knowledge structures from a controlled vocabulary affect tagging. The study is a comparative analysis of tags assigned in two tagging systems, a simple tagging system (control system) that provides suggestions from two tag clouds (all users tags and my tags...... vocabulary might help taggers in being more specific in their tagging, allowing more precise information searching based on user tags. In addition, the results indicate that structured controlled suggestions might encourage taggers to add synonym variations enhancing the variety and number of access points....... Furthermore, controlled vocabularies might be useful for automatic spell checking. Future study should explore in what direction the different kinds of suggestions lead the tagger and whether it is possible to identify scope or patterns between related tags from the two systems....

  10. Compilation of HPSG to TAG

    CERN Document Server

    Kasper, R; Netter, K; Vijay-Shanker, K; Kasper, Robert; Kiefer, Bernd; Netter, Klaus

    1995-01-01

    We present an implemented compilation algorithm that translates HPSG into lexicalized feature-based TAG, relating concepts of the two theories. While HPSG has a more elaborated principle-based theory of possible phrase structures, TAG provides the means to represent lexicalized structures more explicitly. Our objectives are met by giving clear definitions that determine the projection of structures from the lexicon, and identify maximal projections, auxiliary trees and foot nodes.

  11. EXPRESSION OF SV40 Tag AND FORMATION Tag-p53 AND Tag-Rb COMPLEXES IN CHINESE BRAIN TUMORS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To investigate the expression of SV40 Tag andformation of Tag-p53 and Tag-Rb complexes in Chinese brain tumors. Methods: SV40 large tumor antigen (Tag) were investigated by immunoprecipitation, silver staining and Western blot in 65 cases of Chinese brain tumors and 8 cases of normal brain tissues. Tag-p53 and Tag-Rb complexes were screened by the same way in 20 and 15 Tag positive tumor tissues respectively. Results: Tag was found in all of 8 ependymomas and 2 choroid plexus papillomas, 90% (9/10) of pituitary adenomas, 73% (11/15) of astrocytomas, 70% (7/10) of meningiomas, 50% (4/8) of glioblastoma multiform, 33% (2/6) of medulloblastomas, 5 oligodendrogliomas, 1 pineocytoma and 8 normal brain tissues were negative for Tag. Tag-p53 complex was detected in all of 20 Tag positive tumors as well as Tag-Rb complex in all of 15 Tag positive tumors. Conclusion: SV40 Tag is not only expressed in human brain tumors, but also it can form specific complexes with tumor suppressors p53 and Rb. SV40 is correlated to human brain tumorigenesis. The inactivation of p53 and Rb due to the formation of Tag-p53 and Tag-Rb complexes is possibly an important mechanism in the etiopathogenesis of human brain tumors.

  12. Noise Studies of Externally Dispersed Interferometry for Doppler Velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D J; Edelstein, J; Lloyd, J; Muirhead, P

    2006-05-04

    Externally Dispersed Interferometry (EDI) is the series combination of a fixed-delay field-widened Michelson interferometer with a dispersive spectrograph. This combination boosts the spectrograph performance for both Doppler velocimetry and high resolution spectroscopy. The interferometer creates a periodic comb that multiplies against the input spectrum to create moire fringes, which are recorded in combination with the regular spectrum. Both regular and high-frequency spectral components can be recovered from the data--the moire component carries additional information that increases the signal to noise for velocimetry and spectroscopy. Here we present simulations and theoretical studies of the photon limited Doppler velocity noise in an EDI. We used a model spectrum of a 1600K temperature star. For several rotational blurring velocities 0, 7.5, 15 and 25 km/s we calculated the dimensionless Doppler quality index (Q) versus wavenumber v. This is the normalized RMS of the derivative of the spectrum and is proportional to the photon-limited Doppler signal to noise ratio.

  13. Real-time image processing for particle tracking velocimetry

    Science.gov (United States)

    Kreizer, Mark; Ratner, David; Liberzon, Alex

    2010-01-01

    We present a novel high-speed particle tracking velocimetry (PTV) experimental system. Its novelty is due to the FPGA-based, real-time image processing "on camera". Instead of an image, the camera transfers to the computer using a network card, only the relevant information of the identified flow tracers. Therefore, the system is ideal for the remote particle tracking systems in research and industrial applications, while the camera can be controlled and data can be transferred over any high-bandwidth network. We present the hardware and the open source software aspects of the PTV experiments. The tracking results of the new experimental system has been compared to the flow visualization and particle image velocimetry measurements. The canonical flow in the central cross section of a a cubic cavity (1:1:1 aspect ratio) in our lid-driven cavity apparatus is used for validation purposes. The downstream secondary eddy (DSE) is the sensitive portion of this flow and its size was measured with increasing Reynolds number (via increasing belt velocity). The size of DSE estimated from the flow visualization, PIV and compressed PTV is shown to agree within the experimental uncertainty of the methods applied.

  14. Tomographic Particle Image Velocimetry Using Colored Shadow Imaging

    KAUST Repository

    Alarfaj, Meshal K.

    2016-02-01

    Tomographic Particle Image Velocimetry Using Colored Shadow Imaging by Meshal K Alarfaj, Master of Science King Abdullah University of Science & Technology, 2015 Tomographic Particle image velocimetry (PIV) is a recent PIV method capable of reconstructing the full 3D velocity field of complex flows, within a 3-D volume. For nearly the last decade, it has become the most powerful tool for study of turbulent velocity fields and promises great advancements in the study of fluid mechanics. Among the early published studies, a good number of researches have suggested enhancements and optimizations of different aspects of this technique to improve the effectiveness. One major aspect, which is the core of the present work, is related to reducing the cost of the Tomographic PIV setup. In this thesis, we attempt to reduce this cost by using an experimental setup exploiting 4 commercial digital still cameras in combination with low-cost Light emitting diodes (LEDs). We use two different colors to distinguish the two light pulses. By using colored shadows with red and green LEDs, we can identify the particle locations within the measurement volume, at the two different times, thereby allowing calculation of the velocities. The present work tests this technique on the flows patterns of a jet ejected from a tube in a water tank. Results from the images processing are presented and challenges discussed.

  15. The NASA Subsonic Jet Particle Image Velocimetry (PIV) Dataset

    Science.gov (United States)

    Bridges, James; Wernet, Mark P.

    2011-01-01

    Many tasks in fluids engineering require prediction of turbulence of jet flows. The present document documents the single-point statistics of velocity, mean and variance, of cold and hot jet flows. The jet velocities ranged from 0.5 to 1.4 times the ambient speed of sound, and temperatures ranged from unheated to static temperature ratio 2.7. Further, the report assesses the accuracies of the data, e.g., establish uncertainties for the data. This paper covers the following five tasks: (1) Document acquisition and processing procedures used to create the particle image velocimetry (PIV) datasets. (2) Compare PIV data with hotwire and laser Doppler velocimetry (LDV) data published in the open literature. (3) Compare different datasets acquired at the same flow conditions in multiple tests to establish uncertainties. (4) Create a consensus dataset for a range of hot jet flows, including uncertainty bands. (5) Analyze this consensus dataset for self-consistency and compare jet characteristics to those of the open literature. The final objective was fulfilled by using the potential core length and the spread rate of the half-velocity radius to collapse of the mean and turbulent velocity fields over the first 20 jet diameters.

  16. Three-dimensional illumination system for tomographic particle image velocimetry

    Science.gov (United States)

    Zhang, Fen; Song, Yang; Qu, Xiangju; Ji, Yunjing; Li, Zhenhua; He, Anzhi

    2016-10-01

    Tomographic particle image velocimetry (Tomo-PIV) is a new developed technique for three-component threedimensional (3C-3D) velocity measurement of the flow field based on the optical tomographic reconstruction method, and has been received extensive attention of the related industries. Three-dimensional light source illuminating the tracer particles of flow field is a critical application for tomographic particle image velocimetry. Three-dimensional light source not only determines the size of measurement volume and the range of the scope of application, but also has a great influence on the image quality. In this work, we propose a rectangular light amplification system using powell lens, prisms and two reflectors. The system can be optimized if given the system parameters based on the theoretical model. The rectangular light amplification system will be verified experimentally by measuring the cross section size of the illuminated light source. A 60mm×25mm cross section of rectangular three-dimensional light source can be obtained by using the rectangular light amplification system. The experiments demonstrate the the feasibility the proposed system.

  17. Application of Digital Particle Imaging Velocimetry to Turbomachinery

    Science.gov (United States)

    Wernet, Mark P.

    1999-01-01

    Digital Particle Imaging Velocimetry (DPIV) is a powerful measurement technique, which can be used as an alternative or complementary approach to Laser Doppler Velocimetry (LDV) in a wide range of research applications. The instantaneous planar velocity measurements obtained with PIV make it an attractive technique for use in the study of the complex flow fields encountered in turbomachinery. Many of the same issues encountered in the application of LDV to rotating machinery apply in the application of PIV. Techniques for optical access, light sheet delivery, CCD camera technology and particulate seeding are discussed. Results from the successful application of the PIV technique to both the blade passage region of a transonic axial compressor and the diffuser region of a high speed centrifugal compressor are presented. Both instantaneous and time-averaged flow fields were obtained. The 95% confidence intervals for the time-averaged velocity estimates were also determined. Results from the use of PIV to study surge in a centrifugal compressor are discussed. In addition, combined correlation/particle tracking results yielding super-resolution velocity measurements are presented.

  18. Analysis of particle kinematics in spheronization via particle image velocimetry.

    Science.gov (United States)

    Koester, Martin; Thommes, Markus

    2013-02-01

    Spheronization is a wide spread technique in pellet production for many pharmaceutical applications. Pellets produced by spheronization are characterized by a particularly spherical shape and narrow size distribution. The particle kinematic during spheronization is currently not well-understood. Therefore, particle image velocimetry (PIV) was implemented in the spheronization process to visualize the particle movement and to identify flow patterns, in order to explain the influence of various process parameters. The spheronization process of a common formulation was recorded with a high-speed camera, and the images were processed using particle image velocimetry software. A crosscorrelation approach was chosen to determine the particle velocity at the surface of the pellet bulk. Formulation and process parameters were varied systematically, and their influence on the particle velocity was investigated. The particle stream shows a torus-like shape with a twisted rope-like motion. It is remarkable that the overall particle velocity is approximately 10-fold lower than the tip speed of the friction plate. The velocity of the particle stream can be correlated to the water content of the pellets and the load of the spheronizer, while the rotation speed was not relevant. In conclusion, PIV was successfully applied to the spheronization process, and new insights into the particle velocity were obtained.

  19. Systematic Error of Acoustic Particle Image Velocimetry and Its Correction

    Directory of Open Access Journals (Sweden)

    Mickiewicz Witold

    2014-08-01

    Full Text Available Particle Image Velocimetry is getting more and more often the method of choice not only for visualization of turbulent mass flows in fluid mechanics, but also in linear and non-linear acoustics for non-intrusive visualization of acoustic particle velocity. Particle Image Velocimetry with low sampling rate (about 15Hz can be applied to visualize the acoustic field using the acquisition synchronized to the excitation signal. Such phase-locked PIV technique is described and used in experiments presented in the paper. The main goal of research was to propose a model of PIV systematic error due to non-zero time interval between acquisitions of two images of the examined sound field seeded with tracer particles, what affects the measurement of complex acoustic signals. Usefulness of the presented model is confirmed experimentally. The correction procedure, based on the proposed model, applied to measurement data increases the accuracy of acoustic particle velocity field visualization and creates new possibilities in observation of sound fields excited with multi-tonal or band-limited noise signals.

  20. Hypersonic Laminar Boundary Layer Velocimetry with Discrete Roughness on a Flat Plate

    Science.gov (United States)

    Bathel, Brett; Danehy, Paul M.; Inman, Jennifer A.; Watkins, A. Neal; Jones, Stephen B.; Lipford, William E.; Goodman, Kyle Z.; Ivey, Christopher B.; Goyne, Christopher P.

    2010-01-01

    Laminar boundary layer velocity measurements are made on a 10-degree half-angle wedge in a Mach 10 flow. Two types of discrete boundary layer trips were used to perturb the boundary layer gas. The first was a 2-mm tall, 4-mm diameter cylindrical trip. The second was a scaled version of the Orbiter Boundary Layer Transition (BLT) Detailed Test Objective (DTO) trip. Both 1-mm and 2.5-mm tall BLT DTO trips were tested. Additionally, side-view and plan-view axial boundary layer velocity measurements were made in the absence of these tripping devices. The free-stream unit Reynolds numbers tested for the cylindrical trips were 1.7x10(exp 6)/m and 3.3x10(exp 6)/m. The free-stream unit Reynolds number tested for the BLT DTO trips was 1.7x10(exp 6)/m. The angle of attack was kept at approximately 5-degrees for most of the tests resulting in a Mach number of approximately 8.3. These combinations of unit Reynolds numbers and angle of attack resulted in laminar flowfields. To study the precision of the measurement technique, the angle of attack was varied during one run. Nitric-oxide (NO) molecular tagging velocimetry (MTV) was used to obtain averaged axial velocity values and associated uncertainties. These uncertainties are as low as 20 m/s. An interline, progressive scan CCD camera was used to obtain separate images of the initial reference and shifted NO molecules that had been tagged by the laser. The CCD configuration allowed for sub-microsecond sequential acquisition of both images. The maximum planar spatial resolution achieved for the side-view velocity measurements was 0.07-mm in the wall-normal direction by 1.45-mm in the streamwise direction with a spatial depth of 0.5-mm. For the plan-view measurements, the maximum planar spatial resolution in the spanwise and streamwise directions was 0.69-mm by 1.28-mm, respectively, with a spatial depth of 0.5-mm. Temperature sensitive paint (TSP) measurements are provided to compliment the velocity data and to provide further

  1. Semantic Analysis of Tag Similarity Measures in Collaborative Tagging Systems

    CERN Document Server

    Cattuto, Ciro; Hotho, Andreas; Stumme, Gerd

    2008-01-01

    Social bookmarking systems allow users to organise collections of resources on the Web in a collaborative fashion. The increasing popularity of these systems as well as first insights into their emergent semantics have made them relevant to disciplines like knowledge extraction and ontology learning. The problem of devising methods to measure the semantic relatedness between tags and characterizing it semantically is still largely open. Here we analyze three measures of tag relatedness: tag co-occurrence, cosine similarity of co-occurrence distributions, and FolkRank, an adaptation of the PageRank algorithm to folksonomies. Each measure is computed on tags from a large-scale dataset crawled from the social bookmarking system del.icio.us. To provide a semantic grounding of our findings, a connection to WordNet (a semantic lexicon for the English language) is established by mapping tags into synonym sets of WordNet, and applying there well-known metrics of semantic similarity. Our results clearly expose differe...

  2. Tempting To Tag: An Experimental Comparison Of Four Tagging Input Mechanisms

    Directory of Open Access Journals (Sweden)

    Mark Melenhorst

    2010-01-01

    Full Text Available Tagging helps achieve improved indexing and recommendation of resources (e.g., videos or pictures in large data collections. In order to reap the benefits of tagging, people must be persuaded to label the resources they consume. This paper reports on a study in which four different tagging input mechanisms and their effect on users' motivation to tag were compared. The mechanisms consisted of a standard tag input box, a chatbot-like environment, a bookmarking mechanism, and a "tag and vote" game. The results of our experiment show that the use of the nonstandard tagging input mechanisms does not affect users' motivation to tag. In some instances tagging mechanisms were found to distract users from their primary task: consuming resources. Persuading people to tag might be accomplished more effectively by using other motivating tagging mechanisms (e.g., tagging games, or motivation could be created by explaining the usefulness of tagging.

  3. The accuracy of tomographic particle image velocimetry for measurements of a turbulent boundary layer

    Science.gov (United States)

    Atkinson, Callum; Coudert, Sebastien; Foucaut, Jean-Marc; Stanislas, Michel; Soria, Julio

    2011-04-01

    To investigate the accuracy of tomographic particle image velocimetry (Tomo-PIV) for turbulent boundary layer measurements, a series of synthetic image-based simulations and practical experiments are performed on a high Reynolds number turbulent boundary layer at Reθ = 7,800. Two different approaches to Tomo-PIV are examined using a full-volume slab measurement and a thin-volume "fat" light sheet approach. Tomographic reconstruction is performed using both the standard MART technique and the more efficient MLOS-SMART approach, showing a 10-time increase in processing speed. Random and bias errors are quantified under the influence of the near-wall velocity gradient, reconstruction method, ghost particles, seeding density and volume thickness, using synthetic images. Experimental Tomo-PIV results are compared with hot-wire measurements and errors are examined in terms of the measured mean and fluctuating profiles, probability density functions of the fluctuations, distributions of fluctuating divergence through the volume and velocity power spectra. Velocity gradients have a large effect on errors near the wall and also increase the errors associated with ghost particles, which convect at mean velocities through the volume thickness. Tomo-PIV provides accurate experimental measurements at low wave numbers; however, reconstruction introduces high noise levels that reduces the effective spatial resolution. A thinner volume is shown to provide a higher measurement accuracy at the expense of the measurement domain, albeit still at a lower effective spatial resolution than planar and Stereo-PIV.

  4. Tag Based Audio Search Engine

    Directory of Open Access Journals (Sweden)

    Parameswaran Vellachu

    2012-03-01

    Full Text Available The volume of the music database is increasing day by day. Getting the required song as per the choice of the listener is a big challenge. Hence, it is really hard to manage this huge quantity, in terms of searching, filtering, through the music database. It is surprising to see that the audio and music industry still rely on very simplistic metadata to describe music files. However, while searching audio resource, an efficient "Tag Based Audio Search Engine" is necessary. The current research focuses on two aspects of the musical databases 1. Tag Based Semantic Annotation Generation using the tag based approach.2. An audio search engine, using which the user can retrieve the songs based on the users choice. The proposed method can be used to annotation and retrieve songs based on musical instruments used , mood of the song, theme of the song, singer, music director, artist, film director, instrument, genre or style and so on.

  5. Neutral B meson flavor tagging

    Science.gov (United States)

    Wilson, Robert J.

    2001-07-01

    We present an investigation of the use of net charge and kaon identification to tag the flavor of neutral B mesons. The net charge of the neutral B meson decay products is zero if all charged particles are used and slightly non-zero if only undiscriminated hadronic final states are used. The net charge of the kaons alone correctly tags the identity of the neutral meson in at least a third of all decays. We have parametrized the particle identification capability of several techniques, such as dE/dx in time projection chambers, LEP/SLC ring-imaging chambers and an enhanced BaBar DIRC. Using these parametrisations we compare the relative tagging power of each technique to that of an ideal detector.

  6. Neutral B meson flavor tagging

    CERN Document Server

    Wilson, R J

    2001-01-01

    We present an investigation of the use of net charge and kaon identification to tag the flavor of neutral B mesons. The net charge of the neutral B meson decay products is zero if all charged particles are used and slightly non-zero if only undiscriminated hadronic final states are used. The net charge of the kaons alone correctly tags the identity of the neutral meson in at least a third of all decays. We have parametrized the particle identification capability of several techniques, such as dE/dx in time projection chambers, LEP/SLC ring-imaging chambers and an enhanced BaBar DIRC. Using these parametrisations we compare the relative tagging power of each technique to that of an ideal detector. (8 refs).

  7. Tagging, Encoding, and Jones Optimality

    DEFF Research Database (Denmark)

    Danvy, Olivier; Lopez, Pablo E. Martinez

    2003-01-01

    A partial evaluator is said to be Jones-optimal if the result of specializing a self-interpreter with respect to a source program is textually identical to the source program, modulo renaming. Jones optimality has already been obtained if the self-interpreter is untyped. If the selfinterpreter...... is typed, however, residual programs are cluttered with type tags. To obtain the original source program, these tags must be removed. A number of sophisticated solutions have already been proposed. We observe, however, that with a simple representation shift, ordinary partial evaluation is already Jones-optimal...

  8. Magnetic Resonance Velocimetry analysis of an angled impinging jet

    Science.gov (United States)

    Irhoud, Alexandre; Benson, Michael; Verhulst, Claire; van Poppel, Bret; Elkins, Chris; Helmer, David

    2016-11-01

    Impinging jets are used to achieve high heat transfer rates in applications ranging from gas turbine engines to electronics. Despite the importance and relative simplicity of the geometry, simulations historically fail to accurately predict the flow behavior in the vicinity of the flow impingement. In this work, we present results from a novel experimental technique, Magnetic Resonance Velocimetry (MRV), which measures three-dimensional time-averaged velocity without the need for optical access. The geometry considered in this study is a circular jet angled at 45 degrees and impinging on a flat plate, with a separation of approximately seven jet diameters between the jet exit and the impingement location. Two flow conditions are considered, with Reynolds numbers of roughly 800 and 14,000. Measurements from the MRV experiment are compared to predictions from Reynolds Averaged Navier Stokes (RANS) simulations, thus demonstrating the utility of MRV for validation of numerical analyses of impinging jet flow.

  9. Particle image velocimetry new developments and recent applications

    CERN Document Server

    Willert, Christian E

    2008-01-01

    Particle Image Velocimetry (PIV) is a non-intrusive optical measurement technique which allows capturing several thousand velocity vectors within large flow fields instantaneously. Today, the PIV technique has spread widely and differentiated into many distinct applications, from micro flows over combustion to supersonic flows for both industrial needs and research. Over the past decade the measurement technique and the hard- and software have been improved continuously so that PIV has become a reliable and accurate method for "real life" investigations. Nevertheless there is still an ongoing process of improvements and extensions of the PIV technique towards 3D, time resolution, higher accuracy, measurements under harsh conditions and micro- and macroscales. This book gives a synopsis of the main results achieved during the EC-funded network PivNet 2 as well as a survey of the state-of-the-art of scientific research using PIV techniques in different fields of application.

  10. Three-dimensional microscopic light field particle image velocimetry

    Science.gov (United States)

    Truscott, Tadd T.; Belden, Jesse; Ni, Rui; Pendlebury, Jonathon; McEwen, Bryce

    2017-03-01

    A microscopic particle image velocimetry (μ {PIV}) technique is developed based on light field microscopy and is applied to flow through a microchannel containing a backward-facing step. The only hardware difference from a conventional μPIV setup is the placement of a microlens array at the intermediate image plane of the microscope. The method combines this optical hardware alteration with post-capture computation to enable 3D reconstruction of particle fields. From these particle fields, we measure three-component velocity fields, but find that accurate velocity measurements are limited to the two in-plane components at discrete depths through the volume (i.e., 2C-3D). Results are compared with a computational fluid dynamics simulation.

  11. Stereo particle image velocimetry applied to a vortex pipe flow

    Science.gov (United States)

    Zhang, Zherui; Hugo, Ronald J.

    2006-03-01

    Stereo particle image velocimetry (PIV) has been employed to study a vortex generated via tangential injection of water in a 2.25 inch (57 mm) diameter pipe for Reynolds numbers ranging from 1,118 to 63,367. Methods of decreasing pipe-induced optical distortion and the PIV calibration technique are addressed. The mean velocity field analyses have shown spatial similarity and revealed four distinct flow regions starting from the central axis of rotation to the pipe wall in the vortex flows. Turbulence statistical data and vortex core location data suggest that velocity fluctuations are due to the axis of the in-line vortex distorting in the shape of a spiral.

  12. Errors in particle tracking velocimetry with high-speed cameras

    CERN Document Server

    Feng, Yan; Liu, Bin

    2011-01-01

    Velocity errors in particle tracking velocimetry (PTV) are studied. When using high-speed video cameras, the velocity error may increase at a high camera frame rate. This increase in velocity error is due to particle-position uncertainty, which is one of two sources of velocity errors studied here. The other source of error is particle acceleration, which has the opposite trend of diminishing at higher frame rates. Both kinds of errors can propagate into quantities calculated from velocity, such as the kinetic temperature of particles or correlation functions. As demonstrated in a dusty plasma experiment, the kinetic temperature of particles has no unique value when measured using PTV, but depends on the sampling time interval or frame rate. It is also shown that an artifact appears in an autocorrelation function computed from particle positions and velocities, and it becomes more severe when a small sampling-time interval is used. Schemes to reduce these errors are demonstrated.

  13. Photonic Doppler Velocimetry Multiplexing Techniques: Evaluation of Photonic Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Edward Daykin

    2012-05-24

    This poster reports progress related to photonic technologies. Specifically, the authors developed diagnostic system architecture for a Multiplexed Photonic Doppler Velocimetry (MPDV) that incorporates frequency and time-division multiplexing into existing PDV methodology to provide increased channel count. Current MPDV design increases number of data records per digitizer channel 8x, and also operates as a laser-safe (Class 3a) system. Further, they applied heterodyne interferometry to allow for direction-of-travel determination and enable high-velocity measurements (>10 km/s) via optical downshifting. They also leveraged commercially available, inexpensive and robust components originally developed for telecom applications. Proposed MPDV architectures employ only commercially available, fiber-coupled hardware.

  14. Characterization of extrusion flow using particle image velocimetry

    Directory of Open Access Journals (Sweden)

    2009-09-01

    Full Text Available The aim of this study was the characterization of polymer flows within an extrusion die using particle image velocimetry (PIV in very constraining conditions (high temperature, pressure and velocity. Measurements were realized on semi-industrial equipments in order to have test conditions close to the industrial ones. Simple flows as well as disrupted ones were studied in order to determine the capabilities and the limits of the method. The analysis of the velocity profiles pointed out significant wall slip, which was confirmed by rheological measurements based on Mooney's method. Numerical simulations were used to connect the two sets of measurements and to simulate complex velocity profiles for comparison to the experimental ones. A good agreement was found between simulations and experiments providing wall slip is taken into account in the simulation.

  15. Preparation of polystyrene microspheres for laser velocimetry in wind tunnels

    Science.gov (United States)

    Nichols, Cecil E., Jr.

    1987-01-01

    Laser Velocimetry (L/V) had made great strides in replacing intrusive devices for wind tunnel flow measurements. The weakness of the L/V has not been the L/V itself, but proper size seeding particles having known drag characteristics. For many Langley Wind Tunnel applications commercial polystyrene latex microspheres suspended in ethanol, injected through a fluid nozzle provides excellent seeding but was not used due to the high cost. This paper provides the instructions, procedures, and formulations for producing polystyrene latex monodisperse microspheres of 0.6, 1.0, 1.7, 2.0, and 2.7 micron diameters. These are presently being used at Langley Research Center as L/V seeding particles.

  16. Application of Particle Image Velocimetry Technology in Water Tunnel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A display and analysis system for hermetical flow field in water tunnel is developed based on the particle image velocimetry(PIV) technology. It consists of some subsystems, such as lamp-house, imaging, image processing and analyzing, control and particles putting. Taking the flow fields around a sphere and a cylinder model as an example under higher Renolds number 5.8 × 105 in water tunnel, we inquired into the application of the system to water tunnel experiment by cross correlation algorithm. The measure error is less than 2 %. The test results show that the developed system can measure and display the flow field accurately in complex flow field without touching and disturbing. The research work indicates that PIV has lots of potential applications in the underwater flow field measurement.

  17. Dynamic range studies and improvements for multiplexed photonic Doppler velocimetry

    Science.gov (United States)

    Miller, Edward Kirk; Lee, Kevin; Larson, Eric; Daykin, Edward

    2017-01-01

    We present studies of the dynamic range achievable with multiplexed photonic Doppler velocimetry (MPDV) measurements, and we demonstrate some techniques to extend the dynamic range. Improved dynamic range for MPDV measurements is needed in order to track the velocity of the free surface behind a cloud of ejecta, so we have undertaken theoretical and experimental studies of factors affecting dynamic range, particularly in cases where the large number of MPDV probe points precludes high illumination power on each channel. To quantify the potential dynamic range of a given MPDV configuration, we introduce a metric called the frequency-domain number of bits, FNOB, which is less stringent than the formally defined equivalent number of bits (ENOB). This new metric is simple to compute in the lab, and it is well suited to conventional PDV analysis, which does not require digitizer phase coherence beyond tens of nanoseconds.

  18. Particle streak velocimetry and its application to impinging laminar jets

    Science.gov (United States)

    Bergthorson, Jeff; Dimotakis, Paul

    2002-11-01

    The technique of Particle Streak Velocimetry (PSV) was improved to include digital imaging and image processing, allowing it to compete with PIV or LDV in terms of accuracy and ease of implementation. PSV provides advantages over other techniques, such as low particle mass loading, short run time experiments, and high accuracy velocity data through the direct measurement of Lagrangian trajectories. PSV, coupled with measurements of the static (Bernoulli) pressure drop across a well designed nozzle contraction, provided redundancy in the measurement of the axisymmetric impinging laminar jet. The impinging laminar jet was studied in the intermediate regime where the existence of a stagnation plate will affect the flow out of the nozzle. This nozzle separation to diameter ratio, L/d_j, regime has not been well characterized. The results indicate that a one-dimensional streamfunction formulation is not sufficient to characterize this flow.

  19. WebTag: Web browsing into sensor tags over NFC.

    Science.gov (United States)

    Echevarria, Juan Jose; Ruiz-de-Garibay, Jonathan; Legarda, Jon; Alvarez, Maite; Ayerbe, Ana; Vazquez, Juan Ignacio

    2012-01-01

    Information and Communication Technologies (ICTs) continue to overcome many of the challenges related to wireless sensor monitoring, such as for example the design of smarter embedded processors, the improvement of the network architectures, the development of efficient communication protocols or the maximization of the life cycle autonomy. This work tries to improve the communication link of the data transmission in wireless sensor monitoring. The upstream communication link is usually based on standard IP technologies, but the downstream side is always masked with the proprietary protocols used for the wireless link (like ZigBee, Bluetooth, RFID, etc.). This work presents a novel solution (WebTag) for a direct IP based access to a sensor tag over the Near Field Communication (NFC) technology for secure applications. WebTag allows a direct web access to the sensor tag by means of a standard web browser, it reads the sensor data, configures the sampling rate and implements IP based security policies. It is, definitely, a new step towards the evolution of the Internet of Things paradigm.

  20. WebTag: Web Browsing into Sensor Tags over NFC

    Directory of Open Access Journals (Sweden)

    Juan Jose Echevarria

    2012-06-01

    Full Text Available Information and Communication Technologies (ICTs continue to overcome many of the challenges related to wireless sensor monitoring, such as for example the design of smarter embedded processors, the improvement of the network architectures, the development of efficient communication protocols or the maximization of the life cycle autonomy. This work tries to improve the communication link of the data transmission in wireless sensor monitoring. The upstream communication link is usually based on standard IP technologies, but the downstream side is always masked with the proprietary protocols used for the wireless link (like ZigBee, Bluetooth, RFID, etc.. This work presents a novel solution (WebTag for a direct IP based access to a sensor tag over the Near Field Communication (NFC technology for secure applications. WebTag allows a direct web access to the sensor tag by means of a standard web browser, it reads the sensor data, configures the sampling rate and implements IP based security policies. It is, definitely, a new step towards the evolution of the Internet of Things paradigm.

  1. WebTag: Web Browsing into Sensor Tags over NFC

    Science.gov (United States)

    Echevarria, Juan Jose; Ruiz-de-Garibay, Jonathan; Legarda, Jon; Álvarez, Maite; Ayerbe, Ana; Vazquez, Juan Ignacio

    2012-01-01

    Information and Communication Technologies (ICTs) continue to overcome many of the challenges related to wireless sensor monitoring, such as for example the design of smarter embedded processors, the improvement of the network architectures, the development of efficient communication protocols or the maximization of the life cycle autonomy. This work tries to improve the communication link of the data transmission in wireless sensor monitoring. The upstream communication link is usually based on standard IP technologies, but the downstream side is always masked with the proprietary protocols used for the wireless link (like ZigBee, Bluetooth, RFID, etc.). This work presents a novel solution (WebTag) for a direct IP based access to a sensor tag over the Near Field Communication (NFC) technology for secure applications. WebTag allows a direct web access to the sensor tag by means of a standard web browser, it reads the sensor data, configures the sampling rate and implements IP based security policies. It is, definitely, a new step towards the evolution of the Internet of Things paradigm. PMID:23012511

  2. Social image tagging with diverse semantics.

    Science.gov (United States)

    Qian, Xueming; Hua, Xian-Sheng; Tang, Yuan Yan; Mei, Tao

    2014-12-01

    We have witnessed the popularity of image-sharing websites for sharing personal experiences through photos on the Web. These websites allow users describing the content of their uploaded images with a set of tags. Those user-annotated tags are often noisy and biased. Social image tagging aims at removing noisy tags and suggests new relevant tags. However, most existing tag enrichment approaches predominantly focus on tag relevance and overlook tag diversity problem. How to make the top-ranked tags covering a wide range of semantic is still an opening, yet challenging, issue. In this paper, we propose an approach to retag social images with diverse semantics. Both the relevance of a tag to image as well as its semantic compensations to the already determined tags are fused to determine the final tag list for a given image. Different from existing image tagging approaches, the top-ranked tags are not only highly relevant to the image but also have significant semantic compensations with each other. Experiments show the effectiveness of the proposed approach.

  3. A high temperature seeding technique for particle image velocimetry

    Science.gov (United States)

    Wernet, Mark P.; Hadley, Judith A.

    2016-12-01

    Non-intrusive measurements of gas velocities via particle image velocimetry (PIV) or laser Doppler velocimetry (LDV) requires entraining particles into the flow field. There are many techniques and materials available for seeding gas phase flows. However, when the flow temperatures exceed 200 °C, the available options for seed materials becomes limited. In high temperature applications refractory seed materials are required. The established technique for seeding flows with metal oxide powders is via fluidized beds by themselves or in combination with cyclone separators. These systems are fraught with problems which limit their ability to provide consistent, uniform flow seeding. In this work, we describe a technique for reliably introducing metal oxide particles into high temperature flows. The employment of pH stabilization techniques typically used to obtain stable dispersions in ceramic processing can provide a source of seed material for high temperature air flows. By pH stabilizing submicron alumina particles in ethanol, a stable dispersion is obtained which when atomized, produces a high quality aerosol. Commercial grade alumina is used with a moderate size distribution. The technique is not limited to alumina/ethanol and is also demonstrated with an alumina/H2O system. Other ceramic powders in other polar solvents can also be used once their point of zero charge (pHpzc) of the powder in the solvent has been determined. We present an example of the pH stabilized dispersions applied to a very challenging high temperature supersonic flow and a particle dynamics analysis across a shock.

  4. Application of Doppler global velocimetry in cryogenic wind tunnels

    Science.gov (United States)

    Willert, C.; Stockhausen, G.; Beversdorff, M.; Klinner, J.; Lempereur, C.; Barricau, P.; Quest, J.; Jansen, U.

    2005-08-01

    A specially designed Doppler global velocimetry system (DGV, planar Doppler velocimetry) was developed and installed in a high-speed cryogenic wind tunnel facility for use at free stream Mach numbers between 0.2 and 0.88, and pressures between 1.2 bar and 3.3 bar. Particle seeding was achieved by injecting a mixture of gaseous nitrogen and water vapor into the dry and cold tunnel flow, which then immediately formed a large amount of small ice crystals. Given the limited physical and optical access for this facility, DGV is considered the best choice for non-intrusive flow field measurements. A multiple branch fiber imaging bundle attached to a common DGV image receiving system simultaneously viewed a common area in the flow field from three different directions through the wind tunnel side walls. The complete imaging system and fiber-fed light sheet generators were installed inside the normally inaccessible pressure plenum surrounding the wind tunnel’s test section. The system control and frequency-stabilized laser system were placed outside of the pressure shell. With a field of view of 300×300 mm2, the DGV system acquired flow maps at a spatial resolution of 3×3 mm2 in the wake of simple vortex generators as well as in the wake of different wing-tip devices on a half-span aircraft model. Although problems mainly relating to light reflections and icing on the observation windows significantly impaired part of the measurements, the remotely controlled hardware operated reliably over the course of three months.

  5. Application of Doppler global velocimetry in cryogenic wind tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Willert, C.; Stockhausen, G.; Beversdorff, M.; Klinner, J. [German Aerospace Center (DLR), Institute of Propulsion Technology, Koeln (Germany); Lempereur, C.; Barricau, P. [DMAE, ONERA, Toulouse Cedex (France); Quest, J.; Jansen, U. [European Transonic Wind Tunnel (ETW), Koeln (Germany)

    2005-08-01

    A specially designed Doppler global velocimetry system (DGV, planar Doppler velocimetry) was developed and installed in a high-speed cryogenic wind tunnel facility for use at free stream Mach numbers between 0.2 and 0.88, and pressures between 1.2 bar and 3.3 bar. Particle seeding was achieved by injecting a mixture of gaseous nitrogen and water vapor into the dry and cold tunnel flow, which then immediately formed a large amount of small ice crystals. Given the limited physical and optical access for this facility, DGV is considered the best choice for non-intrusive flow field measurements. A multiple branch fiber imaging bundle attached to a common DGV image receiving system simultaneously viewed a common area in the flow field from three different directions through the wind tunnel side walls. The complete imaging system and fiber-fed light sheet generators were installed inside the normally inaccessible pressure plenum surrounding the wind tunnel's test section. The system control and frequency-stabilized laser system were placed outside of the pressure shell. With a field of view of 300 x 300 mm{sup 2}, the DGV system acquired flow maps at a spatial resolution of 3 x 3 mm{sup 2} in the wake of simple vortex generators as well as in the wake of different wing-tip devices on a half-span aircraft model. Although problems mainly relating to light reflections and icing on the observation windows significantly impaired part of the measurements, the remotely controlled hardware operated reliably over the course of three months. (orig.)

  6. Tagging the European eel Anguilla anguilla (L.) with coded wire tags

    DEFF Research Database (Denmark)

    Thomassen, S.; Pedersen, Michael Ingemann; Holdensgaard, G.

    2000-01-01

    The coded wire tag (CWT) system was examined as a possible tool for tagging European eels (Anguilla anguilla). Two size groups of eels (3.8 and 10.2 g) were tagged with CWTs in the dorsal musculature, Tag loss 28 days after tagging was 3.1% for the small and 0.7% for the large groups of eels....... Of the tag loss in the small eels, 61% were lost during the first 2 h after tagging. In the small group, eels that lost tags were significantly (P...

  7. Graph based techniques for tag cloud generation

    DEFF Research Database (Denmark)

    Leginus, Martin; Dolog, Peter; Lage, Ricardo Gomes

    2013-01-01

    Tag cloud is one of the navigation aids for exploring documents. Tag cloud also link documents through the user defined terms. We explore various graph based techniques to improve the tag cloud generation. Moreover, we introduce relevance measures based on underlying data such as ratings or citat......Tag cloud is one of the navigation aids for exploring documents. Tag cloud also link documents through the user defined terms. We explore various graph based techniques to improve the tag cloud generation. Moreover, we introduce relevance measures based on underlying data such as ratings...

  8. A Review on Chipless RFID Tag Design

    Directory of Open Access Journals (Sweden)

    Ali Hashemi

    2013-06-01

    Full Text Available The demand for RFID tags has recently increased due to the development of the RFID. Over the past decade, great efforts have been devoted to the design of RFID tags without chip inside. The concept of chipless RFID tags appears to be a promising solution for low cost item tagging because the cost of active RFID tag depends mainly on the chip used in them. This paper presents the progress of the chipless RFID tag and introduces major studies in this filed. Advantages and disadvantages of these methods are pointed out.

  9. Genetic tagging of humpback whales.

    Science.gov (United States)

    Palsbøll, P J; Allen, J; Bérubé, M; Clapham, P J; Feddersen, T P; Hammond, P S; Hudson, R R; Jørgensen, H; Katona, S; Larsen, A H; Larsen, F; Lien, J; Mattila, D K; Sigurjónsson, J; Sears, R; Smith, T; Sponer, R; Stevick, P; Oien, N

    1997-08-21

    The ability to recognize individual animals has substantially increased our knowledge of the biology and behaviour of many taxa. However, not all species lend themselves to this approach, either because of insufficient phenotypic variation or because tag attachment is not feasible. The use of genetic markers ('tags') represents a viable alternative to traditional methods of individual recognition, as they are permanent and exist in all individuals. We tested the use of genetic markers as the primary means of identifying individuals in a study of humpback whales in the North Atlantic Ocean. Analysis of six microsatellite loci among 3,060 skin samples collected throughout this ocean allowed the unequivocal identification of individuals. Analysis of 692 'recaptures', identified by their genotype, revealed individual local and migratory movements of up to 10,000 km, limited exchange among summer feeding grounds, and mixing in winter breeding areas, and also allowed the first estimates of animal abundance based solely on genotypic data. Our study demonstrates that genetic tagging is not only feasible, but generates data (for example, on sex) that can be valuable when interpreting the results of tagging experiments.

  10. Genetic tagging of humpback whales

    NARCIS (Netherlands)

    Palsboll, PJ; Allen, J; Berube, M; Clapham, PJ; Feddersen, TP; Hammond, PS; Hudson, RR; Jorgensen, H; Katona, S; Larsen, AH; Larsen, F; Lien, J; Mattila, DK; Sigurjonsson, J; Sears, R; Smith, T; Sponer, R; Stevick, P; Oien, N

    1997-01-01

    The ability to recognize individual animals has substantially increased our knowledge of the biology and behaviour of many taxa(1). However, not all species lend themselves to this approach, either because of insufficient phenotypic variation or because tag attachment is not feasible. The use of gen

  11. Particle image velocimetry - Principles and first results; La velocimetrie par images de particules. Principes et premiers resultats

    Energy Technology Data Exchange (ETDEWEB)

    Laporta, A.; Marechal, J.P. [Electricite de France (EDF), Direction des Etudes et Recherches, 92 - Clamart (France)

    1997-12-31

    Particle Image Velocimetry (PIV) is a measurement technique elaborated towards the end of the 1970`s, but which has developed considerably in recent years. The general principle of PIV is very simple and enables access to instantaneous velocity fields. It consists in recording images of tracer-particles injected into the flow and determining the distance covered by these particles. Since we know the time lapse between successive images of the same particle, we can derive the local fluid velocity. Among the many existing image acquisition and processing methods, the image inter-correlation analysis techniques, used with a pulsed laser source, is the most effective. Since we know the influence of different parameters (number of particles, beam power, time lapse between two successive images, size of query zones, etc.) on the quality of the final result, we can optimize practical adjustment of the PIV measurement scheme. The PIV was tested on the LAVITA hydraulic mockup (simulating the operation of a tangential fan). First results are, all in all, highly satisfactory. These have enabled the rapid drafting of instantaneous mean velocity field maps (20 images acquired in less than 90 seconds, with a post-processing time of about 10 minutes). Observation of the instantaneous fields has evidenced the presence of low frequency non-stationary phenomena which are not revealed by Laser Doppler Velocimetry (LDV). Quantitative comparison between LDV and PIV, concerning average fields, showed close results, with, however, local divergences which could be relatively marked. It must nevertheless be noted that the PIV measurements performed on LAVITA have not been optimized with a view to obtaining a consistently good accuracy level. Priority in the present case was given to the scope of the field explored, with a view to observing the large non-stationary structures within a flow. The PIV measurement technique is thus operational for prompt flow characterization. However

  12. Quantifying Visual-Representativeness of Social Image Tags Using Image Tag Clarity

    Science.gov (United States)

    Sun, Aixin; Bhowmick, Sourav S.

    Tags associated with images in various social media sharing web sites are valuable information source for superior image retrieval experiences. Due to the nature of tagging, many tags associated with images are not visually descriptive. In this chapter, we propose Image Tag Clarity to evaluate the effectiveness of a tag in describing the visual content of its annotated images, which is also known as the image tag visual-representativeness. It is measured by computing the zero-mean normalized distance between the tag language model estimated from the images annotated by the tag and the collection language model. The tag/collection language models are derived from the bag of visual-word local content features of the images. The visual-representative tags that are commonly used to annotate visually similar images are given high tag clarity scores. Evaluated on a large real-world dataset containing more than 269K images and their associated tags, we show that the image tag clarity score can effectively identify the visual-representative tags from all tags contributed by users. Based on the tag clarity scores, we have made a few interesting observations that could be used to support many tag-based applications.

  13. 50 CFR 635.33 - Archival tags.

    Science.gov (United States)

    2010-10-01

    ...) Implantation report. Any person affixing or implanting an archival tag into a regulated species must obtain... catch, possess, retain, and land an Atlantic HMS in which an archival tag has been implanted or...

  14. The Complex Dynamics of Collaborative Tagging

    NARCIS (Netherlands)

    Halpin, H.; Robu, V.; Shepherd, H.

    2007-01-01

    The debate within the Web community over the optimal means by which to organize information often pits formalized classifications against distributed collaborative tagging systems. A number of questions remain unanswered, however, regarding the nature of collaborative tagging systems including wheth

  15. HMSRP Hawaiian Monk Seal Tag Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains records for all tags applied to Hawaiian monk seals since 1981. These tags were applied by PSD personnel and cooperating scientists as part of...

  16. Satellite Tags- Guam/CNMI EEZ

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Satellite tagging was implemented in 2013. Satellite tagging is conducted using a Dan Inject air rifle and deployment arrows designed by Wildlife Computers. Two...

  17. Tomographic Aperture-Encoded Particle Tracking Velocimetry: A New Approach to Volumetric PIV

    Science.gov (United States)

    Troolin, Dan; Boomsma, Aaron; Lai, Wing; Pothos, Stamatios; Fluid Mechanics Research Instruments Team

    2016-11-01

    Volumetric velocity fields are useful in a wide variety of fluid mechanics applications. Several types of three-dimensional imaging methods have been used in the past to varying degrees of success, for example, 3D PTV (Maas et al., 1993), DDPIV (Peireira et al., 2006), Tomographic PIV (Elsinga, 2006), and V3V (Troolin and Longmire, 2009), among others. Each of these techniques has shown advantages and disadvantages in different areas. With the advent of higher resolution and lower noise cameras with higher stability levels, new techniques are emerging that combine the advantages of the existing techniques. This talk describes a new technique called Tomographic Aperture-Encoded Particle Tracking Velocimetry (TAPTV), in which segmented triangulation and diameter tolerance are used to achieve three-dimensional particle tracking with extremely high particle densities (on the order of ppp = 0.2 or higher) without the drawbacks normally associated with ghost particles (for example in TomoPIV). The results are highly spatially-resolved data with very fast processing times. A detailed explanation of the technique as well as plots, movies, and experimental considerations will be discussed.

  18. Fourier-based layout for grating function structure in spatial filtering velocimetry

    Science.gov (United States)

    Schaeper, M.; Damaschke, N.

    2017-04-01

    Optical spatial filtering velocimetry (SFV) has been used for several decades for velocity measurements. Since the 1990s, charge-coupled device (CCD) line sensors have been used for the realization of spatial filtering systems by the inherent implementation of grating functions using a specialized clock regime. Another approach is the realization of optical SFV systems by utilizing array detectors (CCD or CMOS) with software-implemented grating functions, especially for two-dimensional velocity measurements. Choosing a suitable grating function for the observed scene can be an obstacle when using SFV, and relies on the experience of the user. With this in mind, this contribution presents an overview of how to assemble an optical spatial filtering system. After a general description of signal generation in spatial filtering systems, a straightforward approach to identifying matching harmonic grating functions by using Fourier analysis is presented. This approach has particular advantages for observed scenes with a periodically structured pattern, which were problematic when using SFV in connection with a fixed grating function. Matching periods of harmonic grating functions can be found as peaks in the spectral density distribution of the imaged scene. Once a matching grating function has been found, the signal processing can be made with SFV, which is simpler than calculating the cross-correlation of full frames and is suitable for real-time application. Criteria for the layout of an array-detector-based spatial filtering velocimeter are then discussed.

  19. Multilabel Learning for Automatic Web Services Tagging

    OpenAIRE

    Mustapha AZNAG; Mohamed QUAFAFOU; Jarir, Zahi

    2014-01-01

    Recently, some web services portals and search engines as Biocatalogue and Seekda!, have allowed users to manually annotate Web services using tags. User Tags provide meaningful descriptions of services and allow users to index and organize their contents. Tagging technique is widely used to annotate objects in Web 2.0 applications. In this paper we propose a novel probabilistic topic model (which extends the CorrLDA model - Correspondence Latent Dirichlet Allocation-) to automatically tag we...

  20. ON THE INTERACTIVE FUNCTIONS OF TAG QUESTIONS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Tag questions are a distinctive feature in spokenEnglish,but seldom used by the non-native speakers.Studies show that tags are employed by native speakersmainly to express their interactive and interpersonalmeaning.In this paper,the writer explores the natureof tag questions,mainly their interactive and inter-personal functions in daily coversation.Suggestionsare made with regard to the teaching of tags in theclassroom.

  1. Measuring the 3D motion of particles in microchannel acoustophoresis using astigmatism particle tracking velocimetry

    DEFF Research Database (Denmark)

    Augustsson, P.; Barnkob, Rune; Bruus, Henrik;

    2012-01-01

    We introduce full three-dimensional tracking of particles in an acoustophoresis microchannel using Astigmatism Particle Tracking Velocimetry (APTV) [1]. For the first time the interaction between acoustic streaming and the primary acoustic radiation force in microchannel acoustophoresis...

  2. High-Definition Optical Velocimetry: A New Diagnostic Paradigm for Nuclear Security

    Energy Technology Data Exchange (ETDEWEB)

    Daykin, E; Diaz, A; Gallegos, C; Iverson, A; Perez, C; Rutkowski, A; Holtkamp, D

    2012-06-01

    This slide-show describes work done to address the challenge of high-definition optical velocimetry with hundred(s) of high-fidelity velocity vs. time measurements. After a review of the historical context and a general technical description of how optical velocimetry, particularly photonic Doppler velocimetry, works, the innovation of multiplexed photonic Doppler velocimetry (MPDV) is described as implemented with commercially available telecom products and dense wavelength division multiplexing (DWDM). High amplification of small signals allows for laser-safe operations. The authors have evaluated and leveraged telecom components– optical amplifiers, wavelength multiplexers, and seed lasers–to provide an economical, compact and rugged approach to system architecture. Fourier transform data analysis is seen to be robust and capable of discriminating simultaneous data traces recorded onto a single digitizer channel. The authors successfully fielded demonstration MPDV system on shock driven experiments.

  3. Seeding optimization for instantaneous volumetric velocimetry. Application to a jet in crossflow

    CERN Document Server

    Cambonie, Tristan

    2014-01-01

    Every volumetric velocimetry measurements based on tracer (particles, bubbles, etc.) detection can be strongly influenced by the optical screening phenomenon. It has to be taken into account when the the statistical properties associated to the performances of the particle detection and tracking algorithms are significantly affected. It leads to a maximum concentration of particles in the images thus limiting the final spatial resolution of the instantaneous three-dimensional three-components (3D3C) velocity fields. A volumetric velocimetry system based on Defocused Digital Particle Image Velocimetry is used to show that above a critical visual concentration of particles in the images, the concentration and accuracy of the final instantaneous raw velocity vector field drop. The critical concentration depends on physical parameters as well as on the processing algorithms. Three distinct regimes are identified. In the first regime, the concentration is well adapted to volumetric velocimetry, the largest concent...

  4. Towards EPC compatible plastic RFID tags

    NARCIS (Netherlands)

    Myny, K.; Steudel, S.; Vicca, P.; Smout, S.; Beenhakkers, M.J.; Aerle, N.A.J.M. van; Furthner, F.; Putten, B. van der; Tripathi, A.K.; Gelinck, G.H.; Genoe, J.; Dehaene, W.; Heremans, P.

    2010-01-01

    A target application for plastic RFID tags is Electronic Product Coding (EPC). The EPC-specifications set some demanding requirements for RFID tags. In this work, we review the work that has been done to fulfill some of these specifications. We describe a complete 64-bit RFID tag that is inductively

  5. Towards EPC compatible plastic RFID tags

    NARCIS (Netherlands)

    Myny, K.; Steudel, S.; Vicca, P.; Smout, S.; Beenhakkers, M.J.; Aerle, N.A.J.M. van; Furthner, F.; Putten, B. van der; Tripathi, A.K.; Gelinck, G.H.; Genoe, J.; Dehaene, W.; Heremans, P.

    2010-01-01

    A target application for plastic RFID tags is Electronic Product Coding (EPC). The EPC-specifications set some demanding requirements for RFID tags. In this work, we review the work that has been done to fulfill some of these specifications. We describe a complete 64-bit RFID tag that is inductively

  6. Towards EPC compatible plastic RFID tags

    NARCIS (Netherlands)

    Myny, K.; Steudel, S.; Vicca, P.; Smout, S.; Beenhakkers, M.J.; Aerle, N.A.J.M. van; Furthner, F.; Putten, B. van der; Tripathi, A.K.; Gelinck, G.H.; Genoe, J.; Dehaene, W.; Heremans, P.

    2010-01-01

    A target application for plastic RFID tags is Electronic Product Coding (EPC). The EPC-specifications set some demanding requirements for RFID tags. In this work, we review the work that has been done to fulfill some of these specifications. We describe a complete 64-bit RFID tag that is

  7. ATLAS boosted object tagging 2

    CERN Document Server

    Caudron, Julien; The ATLAS collaboration

    2015-01-01

    A detailed study into the optimal techniques for identifying boosted hadronically decaying W or Z bosons is presented. Various algorithms for reconstructing, grooming and tagging bosonic jets are compared for W bosons with a wide range of transverse momenta using 8 TeV data and 8 TeV and 13 TeV MC simulations. In addition, given that a hadronic jet has been identified as resulting from the hadronic decay of a W or Z, a technique is developed to discriminate between W and Z bosons. The modeling of the tagging variables used in this technique is studied using 8 TeV pp collision data and systematic uncertainties for the tagger efficiency and fake rates are evaluated.

  8. POS Tagging Using Relaxation Labelling

    CERN Document Server

    Padro, L

    1995-01-01

    Relaxation labelling is an optimization technique used in many fields to solve constraint satisfaction problems. The algorithm finds a combination of values for a set of variables such that satisfies -to the maximum possible degree- a set of given constraints. This paper describes some experiments performed applying it to POS tagging, and the results obtained. It also ponders the possibility of applying it to word sense disambiguation.

  9. Digital magnetic tagging for multiplexed suspension-based biochemical assays

    Science.gov (United States)

    Mitrelias, T.; Trypiniotis, T.; Palfreyman, J. J.; Hong, B.; Vyas, K.; Hayward, T. J.; Llandro, J.; Kopper, K. P.; Bland, J. A. C.; Robertson, P. A.; Barnes, C. H. W.

    2009-04-01

    Microarrays and suspension (or bead)-based technologies have attracted significant interest for their broad applications in high throughput molecular biology. However, the throughput of microarrays will always be limited by the array density and the slow diffusion of molecules to their binding sites. Suspension-based technologies, in which all the reactions take place directly on the surface of microcarriers functionalized with molecular probes, could offer true multiplexing due to the possibility of extending their detection capability by a straightforward expansion of the size of the chemical library of probes. To fully exploit their potential, the microcarriers must be tagged, but the number of distinct codes available from spectrometric/graphical/physical encoding methods is currently fairly limited. A digital magnetic tagging method based on magnetic microtags, which have been anisotropy engineered to provide stable magnetization directions which correspond to digital codes, is reported. The tags can be suspended in solution and functionalized with a variety of biological molecular probes. Magnetic tagging offers several benefits compared to the traditional optical encoding techniques currently employed. It offers minimal background signals, potential for a large number of distinct codes, miniaturization of devices, and the ability to write a code in situ. Experimental data showing the reading of individual magnetic microbars from samples comprising 50×20 μm2 Ni elements, as well as micromagnetic simulations that show the feasibility of stray field detection, are presented. The stray fields of the magnetic microbars spanning a range of 60 mOe were detected by a microfabricated fluxgate sensor scanned in a raster fashion over the sample that was placed about 70 μm away. Free floating tags have also been fabricated for use in microfluidic systems. A magnetic lab-on-a-chip device could be used for tagging biomolecular probes for applications in genome

  10. Approximation properties of haplotype tagging

    Directory of Open Access Journals (Sweden)

    Dreiseitl Stephan

    2006-01-01

    Full Text Available Abstract Background Single nucleotide polymorphisms (SNPs are locations at which the genomic sequences of population members differ. Since these differences are known to follow patterns, disease association studies are facilitated by identifying SNPs that allow the unique identification of such patterns. This process, known as haplotype tagging, is formulated as a combinatorial optimization problem and analyzed in terms of complexity and approximation properties. Results It is shown that the tagging problem is NP-hard but approximable within 1 + ln((n2 - n/2 for n haplotypes but not approximable within (1 - ε ln(n/2 for any ε > 0 unless NP ⊂ DTIME(nlog log n. A simple, very easily implementable algorithm that exhibits the above upper bound on solution quality is presented. This algorithm has running time O((2m - p + 1 ≤ O(m(n2 - n/2 where p ≤ min(n, m for n haplotypes of size m. As we show that the approximation bound is asymptotically tight, the algorithm presented is optimal with respect to this asymptotic bound. Conclusion The haplotype tagging problem is hard, but approachable with a fast, practical, and surprisingly simple algorithm that cannot be significantly improved upon on a single processor machine. Hence, significant improvement in computatational efforts expended can only be expected if the computational effort is distributed and done in parallel.

  11. Predicting floods with Flickr tags.

    Science.gov (United States)

    Tkachenko, Nataliya; Jarvis, Stephen; Procter, Rob

    2017-01-01

    Increasingly, user generated content (UGC) in social media postings and their associated metadata such as time and location stamps are being used to provide useful operational information during natural hazard events such as hurricanes, storms and floods. The main advantage of these new sources of data are twofold. First, in a purely additive sense, they can provide much denser geographical coverage of the hazard as compared to traditional sensor networks. Second, they provide what physical sensors are not able to do: By documenting personal observations and experiences, they directly record the impact of a hazard on the human environment. For this reason interpretation of the content (e.g., hashtags, images, text, emojis, etc) and metadata (e.g., keywords, tags, geolocation) have been a focus of much research into social media analytics. However, as choices of semantic tags in the current methods are usually reduced to the exact name or type of the event (e.g., hashtags '#Sandy' or '#flooding'), the main limitation of such approaches remains their mere nowcasting capacity. In this study we make use of polysemous tags of images posted during several recent flood events and demonstrate how such volunteered geographic data can be used to provide early warning of an event before its outbreak.

  12. Tag Clusters as Information Retrieval Interfaces

    CERN Document Server

    Knautz, Kathrin; Stock, Wolfgang G

    2010-01-01

    The paper presents our design of a next generation information retrieval system based on tag co-occurrences and subsequent clustering. We help users getting access to digital data through information visualization in the form of tag clusters. Current problems like the absence of interactivity and semantics between tags or the difficulty of adding additional search arguments are solved. In the evaluation, based upon SERVQUAL and IT systems quality indicators, we found out that tag clusters are perceived as more useful than tag clouds, are much more trustworthy, and are more enjoyable to use.

  13. b-tagging in DELPHI at LEP

    CERN Document Server

    Abdallah, J; Adam, W; Adye, T; Adzic, P; Albrecht, T; Alderweireld, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Almehed, S; Amaldi, Ugo; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W D; Arnoud, Y; Ask, S; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Ballestrero, A; Bambade, P; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Bates, M; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Berntzon, L; Bertrand, D; Besançon, M; Besson, N; Bibby, J; Biffi, P; Bloch, D; Blom, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Branchini, P; Brenner, R; Brodet, E; Brückman, P; Brunet, J M; Bugge, L; Buschmann, P; Caccia, M; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F R; Chabaud, V; Chapkin, M M; Charpentier, P; Checchia, P; Chierici, R; Shlyapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Couchot, F; Crawley, B; Crennell, D J; Cuevas-Maestro, J; D'Almagne, B; D'Hondt, J; Dalmau, J; Da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; De Paula, L S; Di Ciaccio, Lucia; Dijkstra, H; Di Simone, A; Doroba, K; Drees, J; Dris, M; Eigen, G; Ekelöf, T J C; Ellert, M; Elsing, M; Espirito-Santo, M C; Fanourakis, G K; Fassouliotis, D; Feindt, M; Fernández, J; Ferrer, A; Ferro, F; Flagmeyer, U; Föth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J A; Gandelman, M; García, C; Gavillet, P; Gazis, E N; Geralis, T; Gokieli, R; Golob, B; Gómez-Cadenas, J J; Gómez-Ceballos, G; Gonçalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Hansen, J; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Hernando, J A; Herr, H; Heuser, J M; Holmgren, S O; Holt, P J; Houlden, M A; Hultqvist, K; Jackson, J N; Jalocha, P; Jarlskog, C; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Johansson, P D; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Karlsson, M; Katsanevas, S; Katsoufis, E C; Keränen, R; Kernel, G; Kersevan, Borut P; Kiiskinen, A P; King, B T; Kjaer, N J; Kluit, P; Kokkinias, P; Kourkoumelis, C; Kuznetsov, O; Krumshtein, Z; Kucharczyk, M; Kucewicz, W; Kurowska, J; Lamsa, J; Leder, G; Ledroit, F; Leinonen, L; Leitner, R; Lemonne, J; Lepeltier, V; Lesiak, T; Liebig, W; Liko, D; Lipniacka, A; Lopes, J H; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; McNulty, R; Meroni, C; Meyer, W T; Migliore, E; Mitaroff, W A; Mjörnmark, U; Moa, T; Moch, M; Mönig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Müller, U; Münich, K; Mulders, M; Mundim, L; Murray, W; Muryn, B; Myatt, Gerald; Myklebust, T; Nassiakou, M; Navarria, Francesco Luigi; Nawrocki, K; Nicolaidou, R; Niezurawski, P; Nikolenko, M; Nomerotski, A; Norman, A; Nygren, A; Oblakowska-Mucha, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Oyanguren, A; Paganoni, M; Paiano, S; Palacios, J P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V F; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Pukhaeva, N; Pullia, Antonio; Rames, J; Ramler, L; Read, A; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P B; Richard, F; Rídky, J; Rivero, M; Rodríguez, D; Romero, A; Ronchese, P; Rosenberg, E I; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovskii, A; Salmi, L; Salt, J; Savoy-Navarro, A; Schwickerath, U; Segar, A; Sekulin, R L; Siebel, M; Sissakian, A N; Smadja, G; Smirnova, O G; Sokolov, A; Sopczak, A; Sosnowski, R; Spassoff, Tz; Stanitzki, M; Stavitski, I; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli de Fatis, T; Taffard, A C; Tegenfeldt, F; Timmermans, J; Tinti, N; Tkatchev, L G; Tobin, M; Todorovova, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Trischuk, W; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M L; Tyapkin, I A; Tyapkin, P; Tyndel, M; Tzamarias, S; Uvarov, V; Valenti, G; van Dam, P; Van Eldik, J; Van Lysebetten, A; Van Remortel, N; Van Vulpen, I B; Vegni, G; Veloso, F; Venus, W A; Verbeure, F; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weilhammer, Peter; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O P; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zimin, N I; Zinchenko, A I; Zupan, M

    2004-01-01

    The standard method used for tagging b-hadrons in the DELPHI experiment at the CERN LEP Collider is discussed in detail. The main ingredient of b-tagging is the impact parameters of tracks, which relies mostly on the vertex detector. Additional information, such as the mass of particles associated to a secondary vertex, significantly improves the selection efficiency and the background suppression. The paper describes various discriminating variables used for the tagging and the procedure of their combination. In addition, applications of b-tagging to some physics analyses, which depend crucially on the performance and reliability of b-tagging, are described briefly.

  14. Acoustic resolution photoacoustic Doppler velocimetry in blood-mimicking fluids

    Science.gov (United States)

    Brunker, Joanna; Beard, Paul

    2016-02-01

    Photoacoustic Doppler velocimetry provides a major opportunity to overcome limitations of existing blood flow measuring methods. By enabling measurements with high spatial resolution several millimetres deep in tissue, it could probe microvascular blood flow abnormalities characteristic of many different diseases. Although previous work has demonstrated feasibility in solid phantoms, measurements in blood have proved significantly more challenging. This difficulty is commonly attributed to the requirement that the absorber spatial distribution is heterogeneous relative to the minimum detectable acoustic wavelength. By undertaking a rigorous study using blood-mimicking fluid suspensions of 3 μm absorbing microspheres, it was discovered that the perceived heterogeneity is not only limited by the intrinsic detector bandwidth; in addition, bandlimiting due to spatial averaging within the detector field-of-view also reduces perceived heterogeneity and compromises velocity measurement accuracy. These detrimental effects were found to be mitigated by high-pass filtering to select photoacoustic signal components associated with high heterogeneity. Measurement under-reading due to limited light penetration into the flow vessel was also observed. Accurate average velocity measurements were recovered using “range-gating”, which furthermore maps the cross-sectional velocity profile. These insights may help pave the way to deep-tissue non-invasive mapping of microvascular blood flow using photoacoustic methods.

  15. Volumetric microscale particle tracking velocimetry (PTV) in porous media

    Science.gov (United States)

    Guo, Tianqi; Aramideh, Soroush; Ardekani, Arezoo M.; Vlachos, Pavlos P.

    2016-11-01

    The steady-state flow through refractive-index-matched glass bead microchannels is measured using microscopic particle tracking velocimetry (μPTV). A novel technique is developed to volumetrically reconstruct particles from oversampled two-dimensional microscopic images of fluorescent particles. Fast oversampling of the quasi-steady-state flow field in the lateral direction is realized by a nano-positioning piezo stage synchronized with a fast CMOS camera. Experiments at different Reynolds numbers are carried out for flows through a series of both monodispersed and bidispersed glass bead microchannels with various porosities. The obtained velocity fields at pore-scale (on the order of 10 μm) are compared with direct numerical simulations (DNS) conducted in the exact same geometries reconstructed from micro-CT scans of the glass bead microchannels. The developed experimental method would serve as a new approach for exploring the flow physics at pore-scale in porous media, and also provide benchmark measurements for validation of numerical simulations.

  16. Calibration of Direct Velocimetry Using Hot Wire Anemometry

    Science.gov (United States)

    Holland, Michael L.; DeSilva, Upul P.; Johnson, Joseph A., III

    1997-01-01

    We studied the functionality of the IFA300 Hot Wire Anemometry system and its feasibility for the calibration of Direct Estimator Velocimetry (DEV) using Laser Induced Florescence (LIF). The experimental setup consisted of a single-wire hot wire probe measuring one component of velocity, the anemometry computational hardware and software, an HP oscilloscope, and a table fan to produce a simple flow with fluctuations. Measurements were taken at several points in the stream wise and transverse directions in the flow and various parameters recorded such as mean velocities temperature, turbulence intensities, skewness coefficients and flatness coefficients. The IFA300 software also allowed us to perform statistical manipulations such as spectrum analysis on velocities samples and correlation. Utilization of data files, also produced by the anemometry software, and post analysis were performed to produce graphical representations of turbulent intensity versus probe position and a flow field velocity profile. We concluded that the IFA300 Hot Wire Anemometry system is a reliable and functional method for calibration of DEV using LIF. Our future intentions are to set up a test chamber such that both velocity measurement techniques can be applied simultaneously, thus the calibration.

  17. Particle Image Velocimetry studies of bicuspid aortic valve hemodynamics

    Science.gov (United States)

    Saikrishnan, Neelakantan; Yap, Choon-Hwai; Yoganathan, Ajit P.

    2010-11-01

    Bicuspid aortic valves (BAVs) are a congenital anomaly of the aortic valve with two fused leaflets, affecting about 1-2% of the population. BAV patients have much higher incidence of valve calcification & aortic dilatation, which may be related to altered mechanical forces from BAV hemodynamics. This study aims to characterize BAV hemodynamics using Particle Image Velocimetry(PIV). BAV models are constructed from normal explanted porcine aortic valves by suturing two leaflets together. The valves are mounted in an acrylic chamber with two sinuses & tested in a pulsatile flow loop at physiological conditions. 2D PIV is performed to obtain flow fields in three planes downstream of the valve. The stenosed BAV causes an eccentric jet, resulting in a very strong vortex in the normal sinus. The bicuspid sinus vortex appears much weaker, but more unstable. Unsteady oscillatory shear stresses are also observed, which have been associated with adverse biological response; characterization of the hemodynamics of BAVs will provide the first step to understanding these processes better. Results from multiple BAV models of varying levels of stenosis will be presented & higher stenosis corresponded to stronger jets & increased aortic wall shear stresses.

  18. High-speed particle image velocimetry near surfaces.

    Science.gov (United States)

    Lu, Louise; Sick, Volker

    2013-06-24

    Multi-dimensional and transient flows play a key role in many areas of science, engineering, and health sciences but are often not well understood. The complex nature of these flows may be studied using particle image velocimetry (PIV), a laser-based imaging technique for optically accessible flows. Though many forms of PIV exist that extend the technique beyond the original planar two-component velocity measurement capabilities, the basic PIV system consists of a light source (laser), a camera, tracer particles, and analysis algorithms. The imaging and recording parameters, the light source, and the algorithms are adjusted to optimize the recording for the flow of interest and obtain valid velocity data. Common PIV investigations measure two-component velocities in a plane at a few frames per second. However, recent developments in instrumentation have facilitated high-frame rate (>1 kHz) measurements capable of resolving transient flows with high temporal resolution. Therefore, high-frame rate measurements have enabled investigations on the evolution of the structure and dynamics of highly transient flows. These investigations play a critical role in understanding the fundamental physics of complex flows. A detailed description for performing high-resolution, high-speed planar PIV to study a transient flow near the surface of a flat plate is presented here. Details for adjusting the parameter constraints such as image and recording properties, the laser sheet properties, and processing algorithms to adapt PIV for any flow of interest are included.

  19. Doppler Velocimetry of Current Driven Spin Helices in a Two-Dimensional Electron Gas

    Science.gov (United States)

    Yang, Luyi

    Spins in semiconductors provide a pathway towards the development of spin-based electronics. The appeal of spin logic devices lies in the fact that the spin current is even under time reversal symmetry, yielding non-dissipative coupling to the electric field. To exploit the energy-saving potential of spin current it is essential to be able to control it. While recent demonstrations of electrical-gate control in spin-transistor configurations show great promise, operation at room temperature remains elusive. Further progress requires a deeper understanding of the propagation of spin polarization, particularly in the high mobility semiconductors used for devices. This thesis presents the demonstration and application of a powerful new optical technique, Doppler spin velocimetry, for probing the motion of spin polarization at the level of 1 nm on a picosecond time scale. We discuss experiments in which this technique is used to measure the motion of spin helices in high mobility n-GaAs quantum wells as a function of temperature, in-plane electric field, and photoinduced spin polarization amplitude. We find that the spin helix velocity changes sign as a function of wave vector and is zero at the wave vector that yields the largest spin lifetime. This observation is quite striking, but can be explained by the random walk model that we have developed. We discover that coherent spin precession within a propagating spin density wave is lost at temperatures near 150 K. This finding is critical to understanding why room temperature operation of devices based on electrical gate control of spin current has so far remained elusive. We report that, at all temperatures, electron spin polarization co-propagates with the high-mobility electron sea, even when this requires an unusual form of separation of spin density from photoinjected electron density. Furthermore, although the spin packet co-propagates with the two-dimensional electron gas, spin diffusion is strongly suppressed

  20. Parsing of Myanmar sentences with function tagging

    CERN Document Server

    Thant, Win Win; Thein, Ni Lar

    2012-01-01

    This paper describes the use of Naive Bayes to address the task of assigning function tags and context free grammar (CFG) to parse Myanmar sentences. Part of the challenge of statistical function tagging for Myanmar sentences comes from the fact that Myanmar has free-phrase-order and a complex morphological system. Function tagging is a pre-processing step for parsing. In the task of function tagging, we use the functional annotated corpus and tag Myanmar sentences with correct segmentation, POS (part-of-speech) tagging and chunking information. We propose Myanmar grammar rules and apply context free grammar (CFG) to find out the parse tree of function tagged Myanmar sentences. Experiments show that our analysis achieves a good result with parsing of simple sentences and three types of complex sentences.

  1. Enhancing Navigation on Wikipedia with Social Tags

    CERN Document Server

    Zubiaga, Arkaitz

    2012-01-01

    Social tagging has become an interesting approach to improve search and navigation over the actual Web, since it aggregates the tags added by different users to the same resource in a collaborative way. This way, it results in a list of weighted tags describing its resource. Combined to a classical taxonomic classification system such as that by Wikipedia, social tags can enhance document navigation and search. On the one hand, social tags suggest alternative navigation ways, including pivot-browsing, popularity-driven navigation, and filtering. On the other hand, it provides new metadata, sometimes uncovered by documents' content, that can substantially improve document search. In this work, the inclusion of an interface to add user-defined tags describing Wikipedia articles is proposed, as a way to improve article navigation and retrieval. As a result, a prototype on applying tags over Wikipedia is proposed in order to evaluate its effectiveness.

  2. The accuracy of tomographic particle image velocimetry for measurements of a turbulent boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Atkinson, Callum [Monash University, Laboratory for Turbulence Research in Aerospace and Combustion, Department of Mechanical and Aerospace Engineering, Victoria (Australia); Ecole Centrale de Lille, Bd Paul Langevin, Laboratoire de Mecanique de Lille (UMR CNRS 8107), Villeneuve d' Ascq cedex (France); Coudert, Sebastien; Foucaut, Jean-Marc; Stanislas, Michel [Ecole Centrale de Lille, Bd Paul Langevin, Laboratoire de Mecanique de Lille (UMR CNRS 8107), Villeneuve d' Ascq cedex (France); Soria, Julio [Monash University, Laboratory for Turbulence Research in Aerospace and Combustion, Department of Mechanical and Aerospace Engineering, Victoria (Australia)

    2011-04-15

    To investigate the accuracy of tomographic particle image velocimetry (Tomo-PIV) for turbulent boundary layer measurements, a series of synthetic image-based simulations and practical experiments are performed on a high Reynolds number turbulent boundary layer at Re{sub {theta}} = 7,800. Two different approaches to Tomo-PIV are examined using a full-volume slab measurement and a thin-volume ''fat'' light sheet approach. Tomographic reconstruction is performed using both the standard MART technique and the more efficient MLOS-SMART approach, showing a 10-time increase in processing speed. Random and bias errors are quantified under the influence of the near-wall velocity gradient, reconstruction method, ghost particles, seeding density and volume thickness, using synthetic images. Experimental Tomo-PIV results are compared with hot-wire measurements and errors are examined in terms of the measured mean and fluctuating profiles, probability density functions of the fluctuations, distributions of fluctuating divergence through the volume and velocity power spectra. Velocity gradients have a large effect on errors near the wall and also increase the errors associated with ghost particles, which convect at mean velocities through the volume thickness. Tomo-PIV provides accurate experimental measurements at low wave numbers; however, reconstruction introduces high noise levels that reduces the effective spatial resolution. A thinner volume is shown to provide a higher measurement accuracy at the expense of the measurement domain, albeit still at a lower effective spatial resolution than planar and Stereo-PIV. (orig.)

  3. 3.56-bits/cm Compact Inkjet Printed and Application Specific Chipless RFID Tag

    KAUST Repository

    Khan, Munawar M.

    2015-10-26

    © 2002-2011 IEEE. In this letter, a 28.5-bit chipless RFID tag, based on paper substrate and realized using inkjet printing technique is presented. Operating within ultrawideband, the tag occupies a compact size of 2 × 4 cm2. Focusing on applications requiring time and date identification, a novel encoding technique is presented that allows efficient frequency band allocation based on the number of required instances of time and date variables. A figure of merit (FOM) relating coding capacity and tag dimensions coined as code density is also introduced. A systematic design process followed by simulations and verified through measurements reveal a high code density of 3.56 bits/cm2 for the presented chipless tag.

  4. Assessment of PIT tag retention and post-tagging survival in metamorphosing juvenile Sea Lamprey

    Science.gov (United States)

    Simard, Lee G; Sotola, V Alex; Marsden, J Ellen; Miehls, Scott M.

    2017-01-01

    Background: Passive integrated transponder (PIT) tags have been used to document and monitor the movement or behavior of numerous species of fishes. Data on short-term and long-term survival and tag retention are needed before initiating studies using PIT tags on a new species or life stage. We evaluated the survival and tag retention of 153 metamorphosing juvenile Sea Lamprey Petromyzon marinus tagged with 12 mm PIT tags on three occasions using a simple surgical procedure. Results: Tag retention was 100% and 98.6% at 24 h and 28-105 d post-tagging. Of the lamprey that retained their tags, 87.3% had incisions sufficiently healed to prevent further loss. Survival was 100% and 92.7% at 24 h and 41-118 d post-tagging with no significant difference in survival between tagged and untagged control lamprey. Of the 11 lamprey that died, four had symptoms that indicated their death was directly related to tagging. Survival was positively correlated with Sea Lamprey length. Conclusions: Given the overall high level of survival and tag retention in this study, future studies can utilize 12 mm PIT tags to monitor metamorphosing juvenile Sea Lamprey movement and migration patterns.

  5. Improvement of ultrasound speckle image velocimetry using image enhancement techniques.

    Science.gov (United States)

    Yeom, Eunseop; Nam, Kweon-Ho; Paeng, Dong-Guk; Lee, Sang Joon

    2014-01-01

    Ultrasound-based techniques have been developed and widely used in noninvasive measurement of blood velocity. Speckle image velocimetry (SIV), which applies a cross-correlation algorithm to consecutive B-mode images of blood flow has often been employed owing to its better spatial resolution compared with conventional Doppler-based measurement techniques. The SIV technique utilizes speckles backscattered from red blood cell (RBC) aggregates as flow tracers. Hence, the intensity and size of such speckles are highly dependent on hemodynamic conditions. The grayscale intensity of speckle images varies along the radial direction of blood vessels because of the shear rate dependence of RBC aggregation. This inhomogeneous distribution of echo speckles decreases the signal-to-noise ratio (SNR) of a cross-correlation analysis and produces spurious results. In the present study, image-enhancement techniques such as contrast-limited adaptive histogram equalization (CLAHE), min/max technique, and subtraction of background image (SB) method were applied to speckle images to achieve a more accurate SIV measurement. A mechanical sector ultrasound scanner was used to obtain ultrasound speckle images from rat blood under steady and pulsatile flows. The effects of the image-enhancement techniques on SIV analysis were evaluated by comparing image intensities, velocities, and cross-correlation maps. The velocity profiles and wall shear rate (WSR) obtained from RBC suspension images were compared with the analytical solution for validation. In addition, the image-enhancement techniques were applied to in vivo measurement of blood flow in human vein. The experimental results of both in vitro and in vivo SIV measurements show that the intensity gradient in heterogeneous speckles has substantial influence on the cross-correlation analysis. The image-enhancement techniques used in this study can minimize errors encountered in ultrasound SIV measurement in which RBCs are used as flow

  6. Assessment of pressure field calculations from particle image velocimetry measurements

    Science.gov (United States)

    Charonko, John J.; King, Cameron V.; Smith, Barton L.; Vlachos, Pavlos P.

    2010-10-01

    This paper explores the challenges associated with the determination of in-field pressure from DPIV (digital particle image velocimetry)-measured planar velocity fields for time-dependent incompressible flows. Several methods that have been previously explored in the literature are compared, including direct integration of the pressure gradients and solution of different forms of the pressure Poisson equations. Their dependence on grid resolution, sampling rate, velocity measurement error levels and off-axis recording was quantified using artificial data of two ideal sample flow fields—a decaying vortex flow and pulsatile flow between two parallel plates, and real DPIV and pressure data from oscillating flow through a diffuser. The need for special attention to mitigate the velocity error propagation in the pressure estimation is also addressed using a physics-preserving approach based on proper orthogonal decomposition (POD). The results demonstrate that there is no unique or optimum method for estimating the pressure field and the resulting error will depend highly on the type of the flow. However, the virtual boundary, omni-directional pressure integration scheme first proposed by Liu and Katz (2006 Exp. Fluids 41 227-40) performed consistently well in both synthetic and experimental flows. Estimated errors can vary from less than 1% to over 100% with respect to the expected value, though in contrast to more traditional smoothing algorithms, the newly proposed POD-based filtering approach can reduce errors for a given set of conditions by an order of magnitude or more. This analysis offers valuable insight that allows optimizing the choice of methods and parameters based on the flow under consideration.

  7. Peak-locking reduction for particle image velocimetry

    Science.gov (United States)

    Michaelis, Dirk; Neal, Douglas R.; Wieneke, Bernhard

    2016-10-01

    A parametric study of the factors contributing to peak-locking, a known bias error source in particle image velocimetry (PIV), is conducted using synthetic data that are processed with a state-of-the-art PIV algorithm. The investigated parameters include: particle image diameter, image interpolation techniques, the effect of asymmetric versus symmetric window deformation, number of passes and the interrogation window size. Some of these parameters are found to have a profound effect on the magnitude of the peak-locking error. The effects for specific PIV cameras are also studied experimentally using a precision turntable to generate a known rotating velocity field. Image time series recorded using this experiment show a linear range of pixel and sub-pixel shifts ranging from 0 to  ±4 pixels. Deviations in the constant vorticity field (ω z ) reveal how peak-locking can be affected systematically both by varying parameters of the detection system such as the focal distance and f-number, and also by varying the settings of the PIV analysis. A new a priori technique for reducing the bias errors associated with peak-locking in PIV is introduced using an optical diffuser to avoid undersampled particle images during the recording of the raw images. This technique is evaluated against other a priori approaches using experimental data and is shown to perform favorably. Finally, a new a posteriori anti peak-locking filter (APLF) is developed and investigated, which shows promising results for both synthetic data and real measurements for very small particle image sizes.

  8. Laser Doppler velocimetry measurement of turbulent bubbly channel flow

    Energy Technology Data Exchange (ETDEWEB)

    So, S.; Takagi, S.; Matsumoto, Y. [Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan); Morikita, H. [Morikita Shuppan Co. Ltd, 1-4-11,Fujimi Chiyoda-ku, Tokyo 102-0071 (Japan)

    2002-07-01

    Measurements of the turbulence properties of gas-liquid bubbly flows with mono-dispersed 1-mm-diameter bubbles are reported for upward flow in a rectangular channel. Bubble size and liquid-phase velocity were measured using image-processing and laser Doppler velocimetry (LDV), respectively. A description is given of the special arrangements for two-dimensional LDV needed to obtain reliable bubbly flow data, in particular the configuration of the optical system, the distinction of signals from the bubbles and liquid phase. To create the mono-dispersed bubbles, a small amount of surfactant (3-pentanol of 20 ppm) was added to the flow. Whilst this caused a drastic change in bubble size distribution and flow field, it did not affect the turbulence properties of the single-phase flow. In this study, experiments with three different bulk Reynolds numbers (1,350, 4,100, 8,200) were conducted with void fractions less than 1.2%. In all three cases, there was a very high accumulation of bubbles near the wall with bubble slip at the wall. The mean velocity profile of the liquid phase was steeper near the wall owing to the driving force of buoyant bubbles, and the streamwise turbulent intensity in the vicinity of the wall was enhanced. Furthermore the mean velocity profiles of the liquid phase were flattened in the wide region around the channel center. This region was lifted up by the bubble sheet near the wall, giving it a plug-like flow structure. In addition, the turbulent fluctuation and Reynolds stress in the liquid phase are very much suppressed in this region. This strong preferential accumulation near the wall produces the dramatic change of the whole flow structure. (orig.)

  9. Laser Doppler velocimetry measurement of turbulent bubbly channel flow

    Science.gov (United States)

    So, S.; Morikita, H.; Takagi, S.; Matsumoto, Y.

    2002-05-01

    Measurements of the turbulence properties of gas-liquid bubbly flows with mono-dispersed 1-mm-diameter bubbles are reported for upward flow in a rectangular channel. Bubble size and liquid-phase velocity were measured using image-processing and laser Doppler velocimetry (LDV), respectively. A description is given of the special arrangements for two-dimensional LDV needed to obtain reliable bubbly flow data, in particular the configuration of the optical system, the distinction of signals from the bubbles and liquid phase. To create the mono-dispersed bubbles, a small amount of surfactant (3-pentanol of 20 ppm) was added to the flow. Whilst this caused a drastic change in bubble size distribution and flow field, it did not affect the turbulence properties of the single-phase flow. In this study, experiments with three different bulk Reynolds numbers (1,350, 4,100, 8,200) were conducted with void fractions less than 1.2%. In all three cases, there was a very high accumulation of bubbles near the wall with bubble slip at the wall. The mean velocity profile of the liquid phase was steeper near the wall owing to the driving force of buoyant bubbles, and the streamwise turbulent intensity in the vicinity of the wall was enhanced. Furthermore the mean velocity profiles of the liquid phase were flattened in the wide region around the channel center. This region was lifted up by the bubble sheet near the wall, giving it a plug-like flow structure. In addition, the turbulent fluctuation and Reynolds stress in the liquid phase are very much suppressed in this region. This strong preferential accumulation near the wall produces the dramatic change of the whole flow structure.

  10. Development of RAP Tag, a Novel Tagging System for Protein Detection and Purification.

    Science.gov (United States)

    Fujii, Yuki; Kaneko, Mika K; Ogasawara, Satoshi; Yamada, Shinji; Yanaka, Miyuki; Nakamura, Takuro; Saidoh, Noriko; Yoshida, Kanae; Honma, Ryusuke; Kato, Yukinari

    2017-04-01

    Affinity tag systems, possessing high affinity and specificity, are useful for protein detection and purification. The most suitable tag for a particular purpose should be selected from many available affinity tag systems. In this study, we developed a novel affinity tag called the "RAP tag" system, which comprises a mouse antirat podoplanin monoclonal antibody (clone PMab-2) and the RAP tag (DMVNPGLEDRIE). This system is useful not only for protein detection in Western blotting, flow cytometry, and sandwich enzyme-linked immunosorbent assay, but also for protein purification.

  11. Onboard tagging for smart medical devices.

    Science.gov (United States)

    Li, Kejia; Warren, Steve

    2011-01-01

    Most medical devices are 'dumb:' their role is to acquire, display, and forward data. They make few if any operational decisions based on those data. Onboard tagging is a means whereby a device can embed information about itself, its data, and the sensibility of those data into its data stream. This diagnostic add-on offers a move toward 'smart' devices that will have the ability to affect changes in operational modes based on onboard contextual decision making, such as decisions to avoid needless wireless transmission of corrupt data. This paper presents a description of three types of onboard tags that relate to device hardware (type I tag), signal statistics (type II tag), and signal viability for the intended application (type III tag). A custom wireless pulse oximeter is presented as a use case to show how type II and III tags that convey photoplethysmogram (PPG) statistics and usability specifiers can be calculated and embedded into the data stream without degrading performance.

  12. Hypergraph model of social tagging networks

    CERN Document Server

    Zhang, Zi-Ke

    2010-01-01

    The past few years have witnessed the great success of a new family of paradigms, so-called folksonomy, which allows users to freely associate tags to resources and efficiently manage them. In order to uncover the underlying structures and user behaviors in folksonomy, in this paper, we propose an evolutionary hypergrah model to explain the emerging statistical properties. The present model introduces a novel mechanism that one can not only assign tags to resources, but also retrieve resources via collaborative tags. We then compare the model with a real-world dataset: \\emph{Del.icio.us}. Indeed, the present model shows considerable agreement with the empirical data in following aspects: power-law hyperdegree distributions, negtive correlation between clustering coefficients and hyperdegrees, and small average distances. Furthermore, the model indicates that most tagging behaviors are motivated by labeling tags to resources, and tags play a significant role in effectively retrieving interesting resources and ...

  13. Building Tag Clouds in Perl and PHP

    CERN Document Server

    Bumgardner, Jim

    2006-01-01

    Tag clouds are everywhere on the web these days. First popularized by the web sites Flickr, Technorati, and del.icio.us, these amorphous clumps of words now appear on a slew of web sites as visual evidence of their membership in the elite corps of "Web 2.0." This PDF analyzes what is and isn't a tag cloud, offers design tips for using them effectively, and then goes on to show how to collect tags and display them in the tag cloud format. Scripts are provided in Perl and PHP. Yes, some have said tag clouds are a fad. But as you will see, tag clouds, when used properly, have real merits. More

  14. Understanding why users tag: A survey of tagging motivation literature and results from an empirical study

    Science.gov (United States)

    Strohmaier, Markus; Körner, Christian; Kern, Roman

    2012-01-01

    While recent progress has been achieved in understanding the structure and dynamics of social tagging systems, we know little about the underlying user motivations for tagging, and how they influence resulting folksonomies and tags. This paper addresses three issues related to this question. (1) What distinctions of user motivations are identified by previous research, and in what ways are the motivations of users amenable to quantitative analysis? (2) To what extent does tagging motivation vary across different social tagging systems? (3) How does variability in user motivation influence resulting tags and folksonomies? In this paper, we present measures to detect whether a tagger is primarily motivated by categorizing or describing resources, and apply these measures to datasets from seven different tagging systems. Our results show that (a) users’ motivation for tagging varies not only across, but also within tagging systems, and that (b) tag agreement among users who are motivated by categorizing resources is significantly lower than among users who are motivated by describing resources. Our findings are relevant for (1) the development of tag-based user interfaces, (2) the analysis of tag semantics and (3) the design of search algorithms for social tagging systems. PMID:23471473

  15. Learner Corpora without Error Tagging

    Directory of Open Access Journals (Sweden)

    Rastelli, Stefano

    2009-01-01

    Full Text Available The article explores the possibility of adopting a form-to-function perspective when annotating learner corpora in order to get deeper insights about systematic features of interlanguage. A split between forms and functions (or categories is desirable in order to avoid the "comparative fallacy" and because – especially in basic varieties – forms may precede functions (e.g., what resembles to a "noun" might have a different function or a function may show up in unexpected forms. In the computer-aided error analysis tradition, all items produced by learners are traced to a grid of error tags which is based on the categories of the target language. Differently, we believe it is possible to record and make retrievable both words and sequence of characters independently from their functional-grammatical label in the target language. For this purpose at the University of Pavia we adapted a probabilistic POS tagger designed for L1 on L2 data. Despite the criticism that this operation can raise, we found that it is better to work with "virtual categories" rather than with errors. The article outlines the theoretical background of the project and shows some examples in which some potential of SLA-oriented (non error-based tagging will be possibly made clearer.

  16. Security Tagged Architecture Co-Design (STACD)

    Science.gov (United States)

    2015-09-01

    software that uses tagged information. We will develop a tag enabled Operating System (OS) that permits the simplification and reduction in size of...The Security Tagged Architecture Co-Design (STACD) initiative focuses on eliminating inherent software vulnerabilities by redesigning the underlying...hardware and the operating system to enforce software security policies and semantics. The new approach will use a metadata processing unit known as

  17. Social tagging in the life sciences: characterizing a new metadata resource for bioinformatics

    Directory of Open Access Journals (Sweden)

    Tennis Joseph T

    2009-09-01

    Full Text Available Abstract Background Academic social tagging systems, such as Connotea and CiteULike, provide researchers with a means to organize personal collections of online references with keywords (tags and to share these collections with others. One of the side-effects of the operation of these systems is the generation of large, publicly accessible metadata repositories describing the resources in the collections. In light of the well-known expansion of information in the life sciences and the need for metadata to enhance its value, these repositories present a potentially valuable new resource for application developers. Here we characterize the current contents of two scientifically relevant metadata repositories created through social tagging. This investigation helps to establish how such socially constructed metadata might be used as it stands currently and to suggest ways that new social tagging systems might be designed that would yield better aggregate products. Results We assessed the metadata that users of CiteULike and Connotea associated with citations in PubMed with the following metrics: coverage of the document space, density of metadata (tags per document, rates of inter-annotator agreement, and rates of agreement with MeSH indexing. CiteULike and Connotea were very similar on all of the measurements. In comparison to PubMed, document coverage and per-document metadata density were much lower for the social tagging systems. Inter-annotator agreement within the social tagging systems and the agreement between the aggregated social tagging metadata and MeSH indexing was low though the latter could be increased through voting. Conclusion The most promising uses of metadata from current academic social tagging repositories will be those that find ways to utilize the novel relationships between users, tags, and documents exposed through these systems. For more traditional kinds of indexing-based applications (such as keyword-based search to

  18. Effective Personalized Recommendation in Collaborative Tagging Systems

    CERN Document Server

    Zhang, Zi-Ke

    2009-01-01

    Recently, collaborative tagging systems have attracted more and more attention and have been widely applied in web systems. Tags provide highly abstracted information about personal preferences and item content, and are therefore potential to help in improving better personalized recommendations. In this paper, we propose a tag-based recommendation algorithm considering the personal vocabulary and evaluate it in a real-world dataset: Del.icio.us. Experimental results demonstrate that the usage of tag information can significantly improve the accuracy of personalized recommendations.

  19. Using Interference to Block RFID Tags

    DEFF Research Database (Denmark)

    Krigslund, Rasmus; Popovski, Petar; Pedersen, Gert Frølund

    We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag.......We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag....

  20. Using Interference to Block RFID Tags

    DEFF Research Database (Denmark)

    Krigslund, Rasmus; Popovski, Petar; Pedersen, Gert Frølund

    We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag.......We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag....

  1. Saturn's Doppler velocimetry wind measurements with VLT/UVES

    Science.gov (United States)

    Silva, Miguel; Mota Machado, Pedro; Luz, David; Sanchez-Lavega, Agustin; Hueso, Ricardo; Peralta, Javier

    2016-10-01

    We present Doppler wind velocity results of Saturn's zonal flow at ~0.4 mbar pressure level. Our aim is help to constrain the characterization of the equatorial jet at the referred altitude and the latitudinal variation of the zonal winds, to contribute to monitor the spatial and temporal variability in order to achieve a better understanding of the dynamics of Saturn's zonal winds, which Sánchez-Lavega et al. (2003, Nature, 423, 623) have found to have strongly changed in recent years, as the planet approached southern summer solstice.The UVES/VLT instrument has been used, which simultaneously achieves high spectral resolving power and high spatial resolution. The field has been derotated in order to have the aperture aligned perpendicularly to Saturn's rotation axis. In this configuration, spatial information in the East-West direction is preserved in a set of spectra in the direction perpendicular to dispersion.The technique of absolute accelerometry (AA, Connes, 1985, ApSS 110, 211) has been applied to the backscattered solar spectrum in order to determine the Doppler shift associated with the zonal circulation. Our measurements have been made in the wavelength range of 480-680 nm. Previously we successfully adapted this Doppler velocimetry technique for measuring winds at Venus cloud tops (Machado et al. 2012).The observations consisted of 4 blocks of 15 exposures of 90 sec, plus two shorter blocks of 9 exposures, totalling 7.3 hours of telescope time. In order to cover the whole disk the aperture has been offset by 1 arcsec in the North-South direction between consecutive exposures. Most of the northern hemisphere was covered by the rings. Saturn's diameter was 17.4 arcsec, and the slit aperture was 0.3x25 arcsec. The aperture offset between consecutive exposures was 1 arcsec. Two observations blocks of 9 exposures only covered the central part of the disk, and four others covered the whole disk. The sub-terrestrial point was at -26.1 degrees South. The

  2. Investigation of spectral analysis techniques for randomly sampled velocimetry data

    Science.gov (United States)

    Sree, Dave

    1993-01-01

    It is well known that velocimetry (LV) generates individual realization velocity data that are randomly or unevenly sampled in time. Spectral analysis of such data to obtain the turbulence spectra, and hence turbulence scales information, requires special techniques. The 'slotting' technique of Mayo et al, also described by Roberts and Ajmani, and the 'Direct Transform' method of Gaster and Roberts are well known in the LV community. The slotting technique is faster than the direct transform method in computation. There are practical limitations, however, as to how a high frequency and accurate estimate can be made for a given mean sampling rate. These high frequency estimates are important in obtaining the microscale information of turbulence structure. It was found from previous studies that reliable spectral estimates can be made up to about the mean sampling frequency (mean data rate) or less. If the data were evenly samples, the frequency range would be half the sampling frequency (i.e. up to Nyquist frequency); otherwise, aliasing problem would occur. The mean data rate and the sample size (total number of points) basically limit the frequency range. Also, there are large variabilities or errors associated with the high frequency estimates from randomly sampled signals. Roberts and Ajmani proposed certain pre-filtering techniques to reduce these variabilities, but at the cost of low frequency estimates. The prefiltering acts as a high-pass filter. Further, Shapiro and Silverman showed theoretically that, for Poisson sampled signals, it is possible to obtain alias-free spectral estimates far beyond the mean sampling frequency. But the question is, how far? During his tenure under 1993 NASA-ASEE Summer Faculty Fellowship Program, the author investigated from his studies on the spectral analysis techniques for randomly sampled signals that the spectral estimates can be enhanced or improved up to about 4-5 times the mean sampling frequency by using a suitable

  3. Doppler Velocimetry of Current Driven Spin Helices in a Two-Dimensional Electron Gas

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Luyi [Univ. of California, Berkeley, CA (United States)

    2013-05-17

    Spins in semiconductors provide a pathway towards the development of spin-based electronics. The appeal of spin logic devices lies in the fact that the spin current is even under time reversal symmetry, yielding non-dissipative coupling to the electric field. To exploit the energy-saving potential of spin current it is essential to be able to control it. While recent demonstrations of electrical-gate control in spin-transistor configurations show great promise, operation at room temperature remains elusive. Further progress requires a deeper understanding of the propagation of spin polarization, particularly in the high mobility semiconductors used for devices. This dissertation presents the demonstration and application of a powerful new optical technique, Doppler spin velocimetry, for probing the motion of spin polarization at the level of 1 nm on a picosecond time scale. We discuss experiments in which this technique is used to measure the motion of spin helices in high mobility n-GaAs quantum wells as a function of temperature, in-plane electric field, and photoinduced spin polarization amplitude. We find that the spin helix velocity changes sign as a function of wave vector and is zero at the wave vector that yields the largest spin lifetime. This observation is quite striking, but can be explained by the random walk model that we have developed. We discover that coherent spin precession within a propagating spin density wave is lost at temperatures near 150 K. This finding is critical to understanding why room temperature operation of devices based on electrical gate control of spin current has so far remained elusive. We report that, at all temperatures, electron spin polarization co-propagates with the high-mobility electron sea, even when this requires an unusual form of separation of spin density from photoinjected electron density. Furthermore, although the spin packet co-propagates with the two-dimensional electron gas, spin diffusion is strongly

  4. Improving Recommendations in Tag-based Systems with Spectral Clustering of Tag Neighbors

    DEFF Research Database (Denmark)

    Pan, Rong; Xu, Guandong; Dolog, Peter

    2012-01-01

    Tag as a useful metadata reflects the collaborative and conceptual features of documents in social collaborative annotation systems. In this paper, we propose a collaborative approach for expanding tag neighbors and investigate the spectral clustering algorithm to filter out noisy tag neighbors i...

  5. TagCombine:Recommending Tags to Contents in Software Information Sites

    Institute of Scientific and Technical Information of China (English)

    王新宇; 夏鑫; David Lo

    2015-01-01

    Nowadays, software engineers use a variety of online media to search and become informed of new and interesting technologies, and to learn from and help one another. We refer to these kinds of online media which help software engineers improve their performance in software development, maintenance, and test processes as software information sites. In this paper, we propose TagCombine, an automatic tag recommendation method which analyzes objects in software information sites. TagCombine has three different components: 1) multi-label ranking component which considers tag recommendation as a multi-label learning problem; 2) similarity-based ranking component which recommends tags from similar objects; 3) tag-term based ranking component which considers the relationship between different terms and tags, and recommends tags after analyzing the terms in the objects. We evaluate TagCombine on four software information sites, Ask Different, Ask Ubuntu, Freecode, and Stack Overflow. On averaging across the four projects, TagCombine achieves recall@5 and recall@10 to 0.619 8 and 0.762 5 respectively, which improves TagRec proposed by Al-Kofahi et al. by 14.56% and 10.55% respectively, and the tag recommendation method proposed by Zangerle et al. by 12.08% and 8.16% respectively.

  6. Improving Recommendations in Tag-based Systems with Spectral Clustering of Tag Neighbors

    DEFF Research Database (Denmark)

    Pan, Rong; Xu, Guandong; Dolog, Peter

    2012-01-01

    Tag as a useful metadata reflects the collaborative and conceptual features of documents in social collaborative annotation systems. In this paper, we propose a collaborative approach for expanding tag neighbors and investigate the spectral clustering algorithm to filter out noisy tag neighbors...

  7. Multilabel Learning for Automatic Web Services Tagging

    Directory of Open Access Journals (Sweden)

    Mustapha AZNAG

    2014-08-01

    Full Text Available Recently, some web services portals and search engines as Biocatalogue and Seekda!, have allowed users to manually annotate Web services using tags. User Tags provide meaningful descriptions of services and allow users to index and organize their contents. Tagging technique is widely used to annotate objects in Web 2.0 applications. In this paper we propose a novel probabilistic topic model (which extends the CorrLDA model - Correspondence Latent Dirichlet Allocation- to automatically tag web services according to existing manual tags. Our probabilistic topic model is a latent variable model that exploits local correlation labels. Indeed, exploiting label correlations is a challenging and crucial problem especially in multi-label learning context. Moreover, several existing systems can recommend tags for web services based on existing manual tags. In most cases, the manual tags have better quality. We also develop three strategies to automatically recommend the best tags for web services. We also propose, in this paper, WS-Portal; An Enriched Web Services Search Engine which contains 7063 providers, 115 sub-classes of category and 22236 web services crawled from the Internet. In WS-Portal, severals technologies are employed to improve the effectiveness of web service discovery (i.e. web services clustering, tags recommendation, services rating and monitoring. Our experiments are performed out based on real-world web services. The comparisons of Precision@n, Normalised Discounted Cumulative Gain (NDCGn values for our approach indicate that the method presented in this paper outperforms the method based on the CorrLDA in terms of ranking and quality of generated tags.

  8. Cross-validation of 3D particle tracking velocimetry for the study of granular flows down rotating chutes

    NARCIS (Netherlands)

    Shirsath, S.S.; Padding, J.T.; Clercx, H.J.H.; Kuipers, J.A.M.

    2015-01-01

    Three-dimensional particle tracking velocimetry (3D-PTV) is a promising technique to study the behavior of granular flows. The aim of this paper is to cross-validate 3D-PTV against independent or more established techniques, such as particle image velocimetry (PIV), electronic ultrasonic sensor meas

  9. Resolving directional ambiguity in dynamic light scattering-based transverse motion velocimetry in optical coherence tomography

    Science.gov (United States)

    Huang, Brendan K.; Choma, Michael A.

    2014-01-01

    Dynamic Light Scattering-based Optical Coherence Tomography approaches have been successfully implemented to measure total transverse (xy) flow speed, but are unable to resolve directionality. We propose a method to extract directional velocity in the transverse plane by introducing a variable scan bias to our system. Our velocity estimation, which yields the directional velocity component along the scan axis, is also independent of any point spread function calibration. By combining our approach with Doppler velocimetry, we show three-component velocimetry that is appropriately dependent on latitudinal and longitudinal angle. PMID:24487855

  10. To tag or not to tag: animal welfare, conservation and stakeholder considerations in fish tracking studies that use electronic tags

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, Steven J.; Nguyen, Vivian M.; Murchie, Karen J.; Thiem, Jason D.; Donaldson, Michael R.; Hinch, Scott G.; Brown, Richard S.; Fisk, Aaron

    2013-11-01

    The advent and widespread adoption of electronic tags (including biotelemetry and biologging devices) for tracking animals has provided unprecedented information on the biology, management, and conservation of fish in the world’s oceans and inland waters. However, use of these tools is not without controversy. Even when scientific and management objectives may best be achieved using electronic tags, it is increasingly important to further consider other factors such as the welfare of tagged animals (i.e., the role of training and science-based surgical guidelines, anesthetic use, inability to maintain sterile conditions in field environments), the ethics of tagging threatened species vs. using surrogates, stakeholder perspectives on tagging (including aboriginals), as well as use of data emanating from such studies (e.g., by fishers to facilitate exploitation). Failure to do so will have the potential to create conflict and undermine scientific, management and public confidence in the use of this powerful tool. Indeed, there are already a number of examples of where tracking studies using electronic tags have been halted based on concerns raised by researchers, authorities, or stakeholders. Here we present a candid evaluation of several factors that should be considered when determining when to tag or not to tag fish with electronic devices. It is not our objective to judge the merit of previous studies. Rather, we hope to stimulate debate and discussion regarding the use of electronic tags to study fish. Relatedly, there is a need for more research to address these questions (e.g., what level of cleanliness is needed when conducting surgeries, what type of training should be required for fish surgery) including human dimensions studies to understand perspectives of different actors including society as a whole with respect to tagging and tracking studies.

  11. Harnessing Collective Knowledge Inherent in Tag Clouds

    Science.gov (United States)

    Cress, U.; Held, C.

    2013-01-01

    Tagging systems represent the conceptual knowledge of a community. We experimentally tested whether people harness this collective knowledge when navigating through the Web. As a within-factor we manipulated people's prior knowledge (no knowledge vs. prior knowledge that was congruent/incongruent to the collective knowledge inherent in the tags).…

  12. A Radio Tag for Big Whales

    Science.gov (United States)

    Watkins, William A.

    1978-01-01

    Radio tags to track wildlife have been used for years. However, such tagging of whales has been more complicated and less successful. This article explores the latest technology that is designed to give information over a long period of time. (MA)

  13. Baggage Tags for Learning Out of Doors.

    Science.gov (United States)

    Roller, Lib

    The manual provides teachers with not only educational outdoor activities, but also with activities that can be provided on an individual level. The only equipment needed for most of these activities is a bought or homemade "baggage tag". These tags are used for a variety of purposes such as plant and animal identification, nature quiz games, and…

  14. A Radio Tag for Big Whales

    Science.gov (United States)

    Watkins, William A.

    1978-01-01

    Radio tags to track wildlife have been used for years. However, such tagging of whales has been more complicated and less successful. This article explores the latest technology that is designed to give information over a long period of time. (MA)

  15. Towards EPC-compatible organic RFID tags

    NARCIS (Netherlands)

    Myny, K.; Steudel, S.; Vicca, P.; Smout, S.; Beenhakkers, M.J.; Aerle, N.A.J.M. van; Furthner, F.; Putten, B. van der; Tripathi, A.K.; Gelinck, G.H.; Genoe, J.; Dehaene, W.; Heremans, P.L.

    2011-01-01

    In this chapter, fully integrated organic RFID tags are demonstrated. These tags are inductively-coupled at a base frequency of 13.56 MHz and can be read out at distances up to 10 cm, which is the expected readout distance for proximity readers. We also demonstrate next generation transponder chips,

  16. Intrinsic-surface-tag image authentication

    Energy Technology Data Exchange (ETDEWEB)

    Palm, R.G.; DeVolpi, A.

    1991-12-01

    The objective of this work is to further the development of a unique treaty limited item (TLI) intrinsic surface tag for arms control applications. This tag`s unique feature is the ability to capture the sub-micron scale topography of the TLI surface. The surface topography is captured by plastic castings of the surface as digitally imaged by an electron microscope. Tag authentication is accomplished by comparing digital castings images obtained in two different inspections. Surface replication experiments are described, as these experiments from the basis for the authentication algorithm. Both the experiments and the authentication algorithm are analyzed using the modulation transfer function. Recommendations for future improvements in tag authentication are also suggested by the modulation transfer function analysis. 4 refs.

  17. Smart-tag Based Data Dissemination

    DEFF Research Database (Denmark)

    Bonnet, Philippe; Beaufour, Allan; Leopold, Martin

    2002-01-01

    Monitoring wide, hostile areas requires disseminating data between fixed, disconnected clusters of sensor nodes. It is not always possible to install long-range radios in order to cover the whole area. We propose to leverage the movement of mobile individuals, equipped with smart......-tags, to disseminate data across disconnected static nodes spread across a wide area. Static nodes and mobile smart-tags exchange data when they are in the vicinity of each other; smart-tags disseminate data as they move around. In this paper, we propose an algorithm for update propagation and a model for smart......-tag based data dissemination. We use simulation to study the characteristics of the model we propose. Finally, we present an implementation based on Bluetooth smart-tags....

  18. Emergent Community Structure in Social Tagging Systems

    CERN Document Server

    Cattuto, Ciro; Servedio, Vito D P; Loreto, Vittorio

    2008-01-01

    A distributed classification paradigm known as collaborative tagging has been widely adopted in new Web applications designed to manage and share online resources. Users of these applications organize resources (Web pages, digital photographs, academic papers) by associating with them freely chosen text labels, or tags. Here we leverage the social aspects of collaborative tagging and introduce a notion of resource distance based on the collective tagging activity of users. We collect data from a popular system and perform experiments showing that our definition of distance can be used to build a weighted network of resources with a detectable community structure. We show that this community structure clearly exposes the semantic relations among resources. The communities of resources that we observe are a genuinely emergent feature, resulting from the uncoordinated activity of a large number of users, and their detection paves the way for mapping emergent semantics in social tagging systems.

  19. Self-organization in social tagging systems

    CERN Document Server

    Liu, Chuang; Zhang, Zi-Ke

    2011-01-01

    Individuals often imitate each other to fall into the typical group, leading to a self-organized state of typical behaviors in a community. In this paper, we model self-organization in social tagging systems and illustrate the underlying interaction and dynamics. Specifically, we introduce a model in which individuals adjust their own tagging tendency to imitate the average tagging tendency. We found that when users are of low confidence, they tend to imitate others and lead to a self-organized state with active tagging. On the other hand, when users are of high confidence and are stubborn for changes, tagging becomes inactive. We observe a phase transition at a critical level of user confidence when the system changes from one regime to the other. The distributions of post length obtained from the model are compared to real data which show good agreements.

  20. Multipurpose Pressure Vessel Scanner and Photon Doppler Velocimetry

    Science.gov (United States)

    Ellis, Tayera

    2015-01-01

    Critical flight hardware typically undergoes a series of nondestructive evaluation methods to screen for defects before it is integrated into the flight system. Conventionally, pressure vessels have been inspected for flaws using a technique known as fluorescent dye penetrant, which is biased to inspector interpretation. An alternate method known as eddy current is automated and can detect small cracks better than dye penetrant. A new multipurpose pressure vessel scanner has been developed to perform internal and external eddy current scanning, laser profilometry, and thickness mapping on pressure vessels. Before this system can be implemented throughout industry, a probability of detection (POD) study needs to be performed to validate the system’s eddy current crack/flaw capabilities. The POD sample set will consist of 6 flight-like metal pressure vessel liners with defects of known size. Preparation for the POD includes sample set fabrication, system operation, procedure development, and eddy current settings optimization. For this, collaborating with subject matter experts was required. This technical paper details the preparation activities leading up to the POD study currently scheduled for winter 2015/2016. Once validated, this system will be a proven innovation for increasing the safety and reliability of necessary flight hardware.Additionally, testing of frangible joint requires Photon Doppler Velocimetry (PDV) and Digital Image Correlation instrumentation. There is often noise associated with PDV data, which necessitates a frequency modulation (FM) signal-to-noise pre-test. Generally, FM radio works by varying the carrier frequency and mixing it with a fixed frequency source, creating a beat frequency which is represented by audio frequency that can be heard between about 20 to 20,000 Hz. Similarly, PDV reflects a shifted frequency (a phenomenon known as the Doppler Effect) from a moving source and mixes it with a fixed source frequency, which results in

  1. Pop-up Archival Transmitting (PAT) fish tag data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The cooperative tagging center (CTC) began deploying electronic tags in 2002. To date over 300 tags have been deployed. The following species have been monitored:...

  2. Contact electrification in aerosolized monodispersed silica microspheres quantified using laser based velocimetry

    DEFF Research Database (Denmark)

    Alois, Stefano; Merrison, Jonathan P.; Iversen, Jens Jacob

    2017-01-01

    The contact electrification of aerosolized micro particles has been studied using a novel technique involving laser velocimetry. This has allowed the simultaneous determination of size and electrical charge of individual silica microspheres (in the range 1 – 8 µm). Interestingly the particles...

  3. Dual-camera system for high-speed imaging in particle image velocimetry

    CERN Document Server

    Hashimoto, K; Hara, T; Onogi, S; Mouri, H

    2012-01-01

    Particle image velocimetry is an important technique in experimental fluid mechanics, for which it has been essential to use a specialized high-speed camera. However, the high speed is at the expense of other performances of the camera, i.e., sensitivity and image resolution. Here, we demonstrate that the high-speed imaging is also possible with a pair of still cameras.

  4. Selectivity of spatial filtering velocimetry of objective speckles for measuring out-of-plane motion

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Yura, H. T.; Hanson, Steen Grüner

    2012-01-01

    We probe the dynamics of objective laser speckles as the axial distance between the object and the observation plane changes. With the purpose of measuring out-of-plane motion in real time, we apply optical spatial filtering velocimetry to the speckle dynamics. To achieve this, a rotationally sym...

  5. Flow analysis of vortex generators on wing sections by stereoscopic particle image velocimetry measurements

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Hansen, Martin Otto Laver; Cavar, Dalibor

    2008-01-01

    Stereoscopic particle image velocimetry measurements have been executed in a low speed wind tunnel in spanwise planes in the flow past a row of vortex generators, mounted on a bump in a fashion producing counter-rotating vortices. The measurement technique is a powerful tool which provides all...

  6. Investigation of airflow patterns in a microclimate by particle image velocimetry (PIV)

    DEFF Research Database (Denmark)

    Mortensen, Lone Hedegaard; Rode, Carsten; Peuhkuri, Ruut

    2008-01-01

    moisture production. The lack of air circulation decreases the surface temperature, which can cause problems. A particle image velocimetry (PIV) investigation was performed of the airflow patterns in such a microclimate. This paper describes the experimental set-up and the results. The results indicate...

  7. Tomographic particle image velocimetry and its application to turbulent boundary layers

    NARCIS (Netherlands)

    Elsinga, G.E.

    2008-01-01

    Tomographic Particle Image Velocimetry is a new experimental method developed to study three-dimensional motion in turbulent flows. The technique is an extension of standard PIV and makes use of several simultaneous views of illuminated tracer particles and their three-dimensional reconstruction as

  8. Development of multi-spectral three-dimensional micro particle tracking velocimetry

    Science.gov (United States)

    Tien, Wei-Hsin

    2016-08-01

    The color-coded 3D micro particle tracking velocimetry system (CC3DμPTV) is a volumetric velocimetry technique that uses the defocusing digital particle image velocimetry (DDPIV) approach to reconstruct the 3D location of the particle. It is suited for microscopic flow visualization because of the single camera configuration. However, several factors limit the performance of the system. In this study, the limitation of the CC3DμPTV is discussed in detail and a new concept of a multi-camera 3D μ-PTV system is proposed to improve the performance of the original CC3DμPTV system. The system utilizes two dichroic beam splitters to separate the incoming light into 3 spectral ranges, and image with three monochrome image sensors. The use of a color-matched light source, off-center individual pinhole and monochrome image sensors allow the system to achieve better sensitivity and optical resolution. The use of coherent lasers light sources with high-speed cameras improves the velocity measurement dynamic range. The performance of the proposed multi-spectral system is first evaluated with a simulation model based on the finite element method (FEM). The performance is also compared numerically with the CC3DμPTV system. The test results show significant improvements on the signal to noise ratio and optical resolution. Originally presented in 11th International Symposium on Particle Image Velocimetry, Santa Barbara, California, September 14-16, 2015.

  9. QUANTITATIVE FLOW-ANALYSIS AROUND AQUATIC ANIMALS USING LASER SHEET PARTICLE IMAGE VELOCIMETRY

    NARCIS (Netherlands)

    STAMHUIS, EJ; VIDELER, JJ

    1995-01-01

    Two alternative particle image velocimetry (PIV) methods have been developed, applying laser light sheet illumination of particle-seeded flows around marine organisms, Successive video images, recorded perpendicular to a light sheet parallel to the main stream, were digitized and processed to map th

  10. Uncertainty quantification in particle image velocimetry and advances in time-resolved image and data analysis

    NARCIS (Netherlands)

    Sciacchitano, A.

    2014-01-01

    Particle Image Velocimetry (PIV) is a well-established technique for the measurement of the flow velocity in a two or three-dimensional domain. As in any other technique, PIV data is affected by measurement errors, defined as the difference between the measured velocity and its actual value, which i

  11. Multi-pass light amplification for tomographic particle image velocimetry applications

    NARCIS (Netherlands)

    Ghaemi, S.; Scarano, F.

    2010-01-01

    The light source budget is a critical issue for tomographic particle image velocimetry (Tomo-PIV) systems due to its requirement for large illuminated volume and imaging at small apertures. In this work, a light amplification system based on the multi-pass concept is investigated for Tomo-PIV applic

  12. Particle imaging velocimetry experiments and lattice-Boltzmann simulations on a single sphere settling under gravity

    NARCIS (Netherlands)

    Ten Cate, A.; Nieuwstad, C.H.; Derksen, J.J.; Van den Akker, H.E.A.

    2002-01-01

    A comparison is made between experiments and simulations on a single sphere settling in silicon oil in a box. Cross-correlation particle imaging velocimetry measurements were carried out at particle Reynolds numbers ranging from 1.5 to 31.9. The particle Stokes number varied from 0.2 to 4 and at bot

  13. Particle image velocimetry for quantification of high pressure CO 2 release

    NARCIS (Netherlands)

    Jong, A. de; Spruijt, M.

    2013-01-01

    In the current work evaluation of CO2 release velocity profiles is determined using Particle Image Velocimetry (PIV). The formation of solid CO2 particles using the rapid expansion of nozzle flow is used as a seeder particle, making the method truly nonintrusive and negates the use of special seeder

  14. Endovascular Device Testing with Particle Image Velocimetry Enhances Undergraduate Biomedical Engineering Education

    Science.gov (United States)

    Nair, Priya; Ankeny, Casey J.; Ryan, Justin; Okcay, Murat; Frakes, David H.

    2016-01-01

    We investigated the use of a new system, HemoFlow™, which utilizes state of the art technologies such as particle image velocimetry to test endovascular devices as part of an undergraduate biomedical engineering curriculum. Students deployed an endovascular stent into an anatomical model of a cerebral aneurysm and measured intra-aneurysmal flow…

  15. SELF-MIXING LASER-DOPPLER VELOCIMETRY OF LIQUID FLOW AND OF BLOOD PERFUSION IN TISSUE

    NARCIS (Netherlands)

    DEMUL, FFM; KOELINK, MH; WEIJERS, AL; GREVE, J; AARNOUDSE, JG; GRAAFF, R; DASSEL, ACM

    1992-01-01

    The velocimetry method of self-mixing, i.e., the feedback of Doppler-scattered light into the laser cavity, is used for the measurement of liquid flow and of blood perfusion in human tissue. The method is eIucidated by the registration of the blood perfusion of a finger under repeated occlusion of t

  16. PIVlab – Towards User-friendly, Affordable and Accurate Digital Particle Image Velocimetry in MATLAB

    NARCIS (Netherlands)

    Stamhuis, Eize; Thielicke, William

    2014-01-01

    Digital particle image velocimetry (DPIV) is a non-intrusive analysis technique that is very popular for mapping flows quantitatively. To get accurate results, in particular in complex flow fields, a number of challenges have to be faced and solved: The quality of the flow measurements is affected b

  17. PIVlab – Towards User-friendly, Affordable and Accurate Digital Particle Image Velocimetry in MATLAB

    NARCIS (Netherlands)

    Stamhuis, Eize; Thielicke, William

    2014-01-01

    Digital particle image velocimetry (DPIV) is a non-intrusive analysis technique that is very popular for mapping flows quantitatively. To get accurate results, in particular in complex flow fields, a number of challenges have to be faced and solved: The quality of the flow measurements is affected

  18. Three-component particle image velocimetry in a generic can-type gas turbine combustor

    CSIR Research Space (South Africa)

    Meyers, Bronwyn C

    2012-11-01

    Full Text Available -1 Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy November 2012/ Vol. 226(7) Three-componentParticle Image Velocimetry in a Generic Can-type Gas Turbine Combustor B C Meyers 1, 2* , G C Snedden 1 , J P...

  19. QUANTITATIVE FLOW-ANALYSIS AROUND AQUATIC ANIMALS USING LASER SHEET PARTICLE IMAGE VELOCIMETRY

    NARCIS (Netherlands)

    STAMHUIS, EJ; VIDELER, JJ

    Two alternative particle image velocimetry (PIV) methods have been developed, applying laser light sheet illumination of particle-seeded flows around marine organisms, Successive video images, recorded perpendicular to a light sheet parallel to the main stream, were digitized and processed to map

  20. Enhanced UHF RFID tags for drug tracing.

    Science.gov (United States)

    Catarinucci, Luca; Colella, Riccardo; De Blasi, Mario; Patrono, Luigi; Tarricone, Luciano

    2012-12-01

    Radio Frequency Identification (RFID) technology is playing a crucial role for item-level tracing systems in healthcare scenarios. The pharmaceutical supply chain is a fascinating application context, where RFID can guarantee transparency in the drug flow, supporting both suppliers and consumers against the growing counterfeiting problem. In such a context, the choice of the most adequate RFID tag, in terms of shape, frequency, size and reading range, is crucial. The potential presence of items containing materials hostile to the electromagnetic propagation exasperates the problem. In addition, the peculiarities of the different RFID-based checkpoints make even more stringent the requirements for the tag. In this work, the performance of several commercial UHF RFID tags in each step of the pharmaceutical supply chain has been evaluated, confirming the expected criticality. On such basis, a guideline for the electromagnetic design of new high-performance tags capable to overcome such criticalities has been defined. Finally, driven by such guidelines, a new enhanced tag has been designed, realized and tested. Due to patent pending issues, the antenna shape is not shown. Nevertheless, the optimal obtained results do not lose their validity. Indeed, on the one hand they demonstrate that high performance item level tracing systems can actually be implemented also in critical operating conditions. On the other hand, they encourage the tag designer to follow the identified guidelines so to realize enhanced UHF tags.

  1. Time-Tag Generation Script

    Science.gov (United States)

    Jackson, Dan E.

    2010-01-01

    Time-Tag Generation Script (TTaGS) is an application program, written in the AWK scripting language, for generating commands for aiming one Ku-band antenna and two S-band antennas for communicating with spacecraft. TTaGS saves between 2 and 4 person-hours per every 24 hours by automating the repetitious process of building between 150 and 180 antenna-control commands. TTaGS reads a text database of communication satellite schedules and a text database of satellite rise and set times and cross-references items in the two databases. It then compares the scheduled start and stop with the geometric rise and set to compute the times to execute antenna control commands. While so doing, TTaGS determines whether to generate commands for guidance, navigation, and control computers to tell them which satellites to track. To help prevent Ku-band irradiation of the Earth, TTaGS accepts input from the user about horizon tolerance and accordingly restricts activation and effects deactivation of the transmitter. TTaGS can be modified easily to enable tracking of additional satellites and for such other tasks as reading Sun-rise/set tables to generate commands to point the solar photovoltaic arrays of the International Space Station at the Sun.

  2. Communication methods, systems, apparatus, and devices involving RF tag registration

    Science.gov (United States)

    Burghard, Brion J.; Skorpik, James R.

    2008-04-22

    One technique of the present invention includes a number of Radio Frequency (RF) tags that each have a different identifier. Information is broadcast to the tags from an RF tag interrogator. This information corresponds to a maximum quantity of tag response time slots that are available. This maximum quantity may be less than the total number of tags. The tags each select one of the time slots as a function of the information and a random number provided by each respective tag. The different identifiers are transmitted to the interrogator from at least a subset of the RF tags.

  3. Tag gas capsule with magnetic piercing device

    Science.gov (United States)

    Nelson, Ira V.

    1976-06-22

    An apparatus for introducing a tag (i.e., identifying) gas into a tubular nuclear fuel element. A sealed capsule containing the tag gas is placed in the plenum in the fuel tube between the fuel and the end cap. A ferromagnetic punch having a penetrating point is slidably mounted in the plenum. By external electro-magnets, the punch may be caused to penetrate a thin rupturable end wall of the capsule and release the tag gas into the fuel element. Preferably the punch is slidably mounted within the capsule, which is in turn loaded as a sealed unit into the fuel element.

  4. Recommender Systems for Social Tagging Systems

    CERN Document Server

    Balby Marinho, Leandro

    2012-01-01

    Social Tagging Systems are web applications in which users upload resources (e.g., bookmarks, videos, photos, etc.) and annotate it with a list of freely chosen keywords called tags. This is a grassroots approach to organize a site and help users to find the resources they are interested in. Social tagging systems are open and inherently social; features that have been proven to encourage participation. However, with the large popularity of these systems and the increasing amount of user-contributed content, information overload rapidly becomes an issue. Recommender Systems are well known appl

  5. Exploratory Analysis of the Main Characteristics of Tags and Tagging of Educational Resources in a Multi-lingual Context

    OpenAIRE

    Vuorikari, Riina; Ochoa, Xavier

    2009-01-01

    Although social, collaborative classification through tagging has been the focus of recent research, the effect of multi-linguality is often overlooked. This work presents an exploratory study of the production and use of tags in multiple languages in a context of European Learning Resources Exchange. We describe a tagging tool used by teachers from 6 countries and study the main characteristics of tags and how users tag when multiple languages are presented. We find early indication that tag...

  6. Evaluation of in-line spatial filter velocimetry as PAT monitoring tool for particle growth during fluid bed granulation.

    Science.gov (United States)

    Burggraeve, A; Van Den Kerkhof, T; Hellings, M; Remon, J P; Vervaet, C; De Beer, T

    2010-09-01

    In this study, the feasibility of spatial filter velocimetry (SFV) as process analytical technology tool for the in-line monitoring of the particle size distribution during top spray fluidized bed granulation was examined. The influence of several process (inlet air temperature during spraying and drying) and formulation variables (HPMC and Tween 20 concentration) upon the particle size distribution during processing, and the end product particle size distribution, tapped density and Hausner ratio was examined using a design of experiments (DOE) (2-level full factorial design, 19 experiments). The trend in end granule particle size distributions of all DOE batches measured with in-line SFV was similar to the off-line laser diffraction (LD) data. Analysis of the DOE results showed that mainly the HPMC concentration and slightly the inlet air temperature during drying had a positive effect on the average end granule size. The in-line SFV particle size data, obtained every 10s during processing, further allowed to explain and better understand the (in)significance of the studied DOE variables, which was not possible based on the LD data as this technique only supplied end granule size information. The variation in tapped density and Hausner ratio among the end granules of the different DOE batches could be explained by their difference in average end granule size. Univariate, multivariate PLS and multiway N-PLS models were built to relate these end granule properties to the in-line-measured particle size distribution. The multivariate PLS tapped density model and the multiway N-PLS Hausner ratio model showed the highest R(2) values in combination with the lowest RMSEE values (R(2) of 82% with an RMSEE of 0.0279 for tapped density and an R(2) of 52% with an RMSEE of 0.0268 for Hausner ratio, respectively). 2010 Elsevier B.V. All rights reserved.

  7. Comparative Performance of Acoustic-tagged and PIT-tagged Juvenile Salmonids

    Energy Technology Data Exchange (ETDEWEB)

    Hockersmith, Eric E.; Brown, Richard S.; Liedtke, Theresa L.

    2008-02-01

    Numerous research tools and technologies are currently being used to evaluate fish passage and survival to determine the impacts of the Federal Columbia River Power System (FCRPS) on endangered and threatened juvenile salmonids, including PIT tags, balloon tags, hydroacoustic evaluations, radio telemetry, and acoustic telemetry. Each has advantages and disadvantages, but options are restricted in some situations because of limited capabilities of a specific technology, lack of detection capability downstream, or availability of adequate numbers of fish. However, there remains concern about the comparative effects of the tag or the tagging procedure on fish performance. The recently developed Juvenile Salmonid Acoustic Telemetry System (JSATS) acoustic transmitter is the smallest active acoustic tag currently available. The goal of this study was to determine whether fish tagged with the JSATS acoustic-telemetry tag can provide unbiased estimates of passage behavior and survival within the performance life of the tag. We conducted both field and laboratory studies to assess tag effects. For the field evaluation we released a total of 996 acoustic-tagged fish in conjunction with 21,026 PIT-tagged fish into the tailrace of Lower Granite Dam on 6 and 13 May. Travel times between release and downstream dams were not significantly different for the majority of the reaches between acoustic-tagged and PIT-tagged fish. In addition to the field evaluation, a series of laboratory experiments were conducted to determine if growth and survival of juvenile Chinook salmon surgically implanted with acoustic transmitters is different than untagged or PIT tagged juvenile Chinook salmon. Only yearling fish with integrated and non-integrated transmitters experienced mortalities, and these were low (<4.5%). Mortality among sub-yearling control and PIT-tag treatments ranged up to 7.7% while integrated and non-integrated treatments had slightly higher rates (up to 8.3% and 7

  8. Symmetric Phase-Only Filtering in Particle-Image Velocimetry

    Science.gov (United States)

    Wemet, Mark P.

    2008-01-01

    Symmetrical phase-only filtering (SPOF) can be exploited to obtain substantial improvements in the results of data processing in particle-image velocimetry (PIV). In comparison with traditional PIV data processing, SPOF PIV data processing yields narrower and larger amplitude correlation peaks, thereby providing more-accurate velocity estimates. The higher signal-to-noise ratios associated with the higher amplitude correlation peaks afford greater robustness and reliability of processing. SPOF also affords superior performance in the presence of surface flare light and/or background light. SPOF algorithms can readily be incorporated into pre-existing algorithms used to process digitized image data in PIV, without significantly increasing processing times. A summary of PIV and traditional PIV data processing is prerequisite to a meaningful description of SPOF PIV processing. In PIV, a pulsed laser is used to illuminate a substantially planar region of a flowing fluid in which particles are entrained. An electronic camera records digital images of the particles at two instants of time. The components of velocity of the fluid in the illuminated plane can be obtained by determining the displacements of particles between the two illumination pulses. The objective in PIV data processing is to compute the particle displacements from the digital image data. In traditional PIV data processing, to which the present innovation applies, the two images are divided into a grid of subregions and the displacements determined from cross-correlations between the corresponding sub-regions in the first and second images. The cross-correlation process begins with the calculation of the Fourier transforms (or fast Fourier transforms) of the subregion portions of the images. The Fourier transforms from the corresponding subregions are multiplied, and this product is inverse Fourier transformed, yielding the cross-correlation intensity distribution. The average displacement of the

  9. Comparing the hierarchy of author given tags and repository given tags in a large document archive

    CERN Document Server

    Tibély, Gergely; Palla, Gergely

    2015-01-01

    Folksonomies - large databases arising from collaborative tagging of items by independent users - are becoming an increasingly important way of categorizing information. In these systems users can tag items with free words, resulting in a tripartite item-tag-user network. Although there are no prescribed relations between tags, the way users think about the different categories presumably has some built in hierarchy, in which more special concepts are descendants of some more general categories. Several applications would benefit from the knowledge of this hierarchy. Here we apply a recent method to check the differences and similarities of hierarchies resulting from tags given by independent individuals and from tags given by a centrally managed repository system. The results from out method showed substantial differences between the lower part of the hierarchies, and in contrast, a relatively high similarity at the top of the hierarchies.

  10. User Interface Program for secure electronic tags

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Y.; Koehl, E.R.; Carlson, R.D.; Raptis, A.C.

    1995-05-01

    This report summarizes and documents the efforts of Argonne National Laboratory (ANL) in developing a secure tag communication user interface program comprising a tag monitor and a communication tool. This program can perform the same functions as the software that was developed at the Lawrence Livermore National Laboratory (LLNL), but it is enhanced with a user-friendly screen. It represents the first step in updating the TRANSCOM Tracking System (TRANSCOM) by incorporating a tag communication screen menu into the main menu of the TRANSCOM user program. A working version of TRANSCOM, enhanced with ANL secure-tag graphics, will strongly support the Department of Energy Warhead Dismantlement/Special Nuclear Materials Control initiatives. It will allow commercial satellite tracking of the movements and operational activities of treaty-limited items and transportation vehicles throughout Europe and the former USSR, as well as the continental US.

  11. Intrinsic-surface-tag image authentication

    Energy Technology Data Exchange (ETDEWEB)

    Palm, R.G.; DeVolpi, A.

    1991-12-01

    The objective of this work is to further the development of a unique treaty limited item (TLI) intrinsic surface tag for arms control applications. This tag's unique feature is the ability to capture the sub-micron scale topography of the TLI surface. The surface topography is captured by plastic castings of the surface as digitally imaged by an electron microscope. Tag authentication is accomplished by comparing digital castings images obtained in two different inspections. Surface replication experiments are described, as these experiments from the basis for the authentication algorithm. Both the experiments and the authentication algorithm are analyzed using the modulation transfer function. Recommendations for future improvements in tag authentication are also suggested by the modulation transfer function analysis. 4 refs.

  12. P systems based on tag operations

    Directory of Open Access Journals (Sweden)

    Yurii Rogozhin

    2012-10-01

    Full Text Available In this article we introduce P systems using Post's tag operation on strings.We show that the computational completeness can be achieved even if the deletion length is equal to one.

  13. Flavour Tagging with the LHCb experiment

    CERN Multimedia

    Birnkraut, Alex

    2015-01-01

    Measurements of flavour oscillations and time-dependent CP asymmetries in neutral B meson systems require knowledge of the b quark production flavour. This identification is performed by the Flavour Tagging.

  14. 50 CFR 20.36 - Tagging requirement.

    Science.gov (United States)

    2010-10-01

    ... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Possession § 20.36 Tagging requirement. No person shall put or... attached, signed by the hunter, stating his address, the total number and species of birds, and the date...

  15. HF Transverse Segmentation and Tagging Jet Capability

    CERN Document Server

    Doroshkevich, E A; Kuleshov, Sergey

    1998-01-01

    So called tagging jets and pile-up were simulated for the optimisation of the HF segmentation. The energy resolution, angular resolution and efficiency of jet reconstruction are defined for different calorimeter segmentation.

  16. Three-Dimensional Stereoscopic Tracking Velocimetry and Experimental/Numerical Comparison of Directional Solidification

    Science.gov (United States)

    Lee, David; Ge, Yi; Cha, Soyoung Stephen; Ramachandran, Narayanan; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Measurement of three-dimensional (3-D) three-component velocity fields is of great importance in both ground and space experiments for understanding materials processing and fluid physics. The experiments in these fields most likely inhibit the application of conventional planar probes for observing 3-D phenomena. Here, we present the investigation results of stereoscopic tracking velocimetry (STV) for measuring 3-D velocity fields, which include diagnostic technology development, experimental velocity measurement, and comparison with analytical and numerical computation. STV is advantageous in system simplicity for building compact hardware and in software efficiency for continual near-real-time monitoring. It has great freedom in illuminating and observing volumetric fields from arbitrary directions. STV is based on stereoscopic observation of particles-Seeded in a flow by CCD sensors. In the approach, part of the individual particle images that provide data points is likely to be lost or cause errors when their images overlap and crisscross each other especially under a high particle density. In order to maximize the valid recovery of data points, neural networks are implemented for these two important processes. For the step of particle overlap decomposition, the back propagation neural network is utilized because of its ability in pattern recognition with pertinent particle image feature parameters. For the step of particle tracking, the Hopfield neural network is employed to find appropriate particle tracks based on global optimization. Our investigation indicates that the neural networks are very efficient and useful for stereoscopically tracking particles. As an initial assessment of the diagnostic technology performance, laminar water jets with and without pulsation are measured. The jet tip velocity profiles are in good agreement with analytical predictions. Finally, for testing in material processing applications, a simple directional solidification

  17. Chemoenzymatic Fc Glycosylation via Engineered Aldehyde Tags

    OpenAIRE

    2014-01-01

    Glycoproteins with chemically defined glycosylation sites and structures are important biopharmaceutical targets and critical tools for glycobiology. One approach toward constructing such molecules involves chemical glycosylation of aldehyde-tagged proteins. Here, we report the installation of a genetically encoded aldehyde tag at the internal glycosylation site of the crystallizable fragment (Fc) of IgG1. We replaced the natural Fc N-glycosylation sequon with a five amino-acid sequence that ...

  18. b-flavour tagging in pp collisions

    CERN Multimedia

    Birnkraut, Alex

    2015-01-01

    An essential ingredient of all time-dependent CP violation studies of B mesons is the ability to tag the initial flavour of the B meson. The harsh environment of 7 and 8 TeV pp collisions makes this a particularly difficult enterprise. We report progresses in the flavour tagging of B0 and Bs mesons, including developments of novel techniques like the use of an opposite side charm tagger.

  19. Chemical Address Tags of Fluorescent Bioimaging Probes

    OpenAIRE

    Shedden, Kerby; Rosania, Gus R.

    2010-01-01

    Chemical address tags can be defined as specific structural features shared by a set of bioimaging probes having a predictable influence on cell-associated visual signals obtained from these probes. Here, using a large image dataset acquired with a high content screening instrument, machine vision and cheminformatics analysis have been applied to reveal chemical address tags. With a combinatorial library of fluorescent molecules, fluorescence signal intensity, spectral, and spatial features c...

  20. RATC: A Robust Automated Tag Clustering Technique

    Science.gov (United States)

    Boratto, Ludovico; Carta, Salvatore; Vargiu, Eloisa

    Nowadays, the most dominant and noteworthy web information sources are developed according to the collaborative-web paradigm, also known as Web 2.0. In particular, it represents a novel paradigm in the way users interact with the web. Users (also called prosumers) are no longer passive consumers of published content, but become involved, implicitly and explicitly, as they cooperate by providing their own resources in an “architecture of participation”. In this scenario, collaborative tagging, i.e., the process of classifying shared resources by using keywords, becomes more and more popular. The main problem in such task is related to well-known linguistic phenomena, such as polysemy and synonymy, making effective content retrieval harder. In this paper, an approach that monitors users activity in a tagging system and dynamically quantifies associations among tags is presented. The associations are then used to create tags clusters. Experiments are performed comparing the proposed approach with a state-of-the-art tag clustering technique. Results -given in terms of classical precision and recall- show that the approach is quite effective in the presence of strongly related tags in a cluster.

  1. Smart-tag Based Data Dissemination

    DEFF Research Database (Denmark)

    Bonnet, Philippe; Beaufour, Allan; Leopold, Martin

    2002-01-01

    Monitoring wide, hostile areas requires disseminating data between fixed, disconnected clusters of sensor nodes. It is not always possible to install long-range radios in order to cover the whole area. We propose to leverage the movement of mobile individuals, equipped with smart-tags, to dissemi......-tag based data dissemination. We use simulation to study the characteristics of the model we propose. Finally, we present an implementation based on Bluetooth smart-tags.......Monitoring wide, hostile areas requires disseminating data between fixed, disconnected clusters of sensor nodes. It is not always possible to install long-range radios in order to cover the whole area. We propose to leverage the movement of mobile individuals, equipped with smart......-tags, to disseminate data across disconnected static nodes spread across a wide area. Static nodes and mobile smart-tags exchange data when they are in the vicinity of each other; smart-tags disseminate data as they move around. In this paper, we propose an algorithm for update propagation and a model for smart...

  2. Purification of GST-Tagged Proteins.

    Science.gov (United States)

    Schäfer, Frank; Seip, Nicole; Maertens, Barbara; Block, Helena; Kubicek, Jan

    2015-01-01

    This protocol describes the purification of recombinant proteins fused to glutathione S-transferase (GST, GST-tagged proteins) by Glutathione Affinity purification. The GST tag frequently increases the solubility of the fused protein of interest and thus enables its purification and subsequent functional characterization. The GST-tagged protein specifically binds to glutathione immobilized to a matrix (e.g., agarose) and can be easily separated from a cell lysate by a bind-wash-elute procedure. GST-tagged proteins are often used to study protein-protein interactions, again making use of glutathione affinity in a procedure called a GST pull-down assay. The protocol is designed to process 200 ml of E. coli culture expressing intermediate to high amounts of a GST-tagged protein (~25 mg l(-1)). Depending on the expression rate or the available culture volume, the scale can be increased or decreased linearly. The protocol can also be used to purify GST-tagged proteins from other expression systems, such as insect or mammalian cells. Tips are provided to aid in modifying certain steps if proteins shall be recovered from alternative expression systems.

  3. Personalized Tag Recommendation Using Social Influence

    Institute of Scientific and Technical Information of China (English)

    Jun Hu; Bing Wang; Yu Liu; De-Yi Li

    2012-01-01

    Tag recommendation encourages users to add more tags in bridging the semantic gap between human concept and the features of media object,which provides a feasible solution for content-based multimedia information retrieval.In this paper,we study personalized tag recommendation in a popular online photo sharing site Flickr.Social relationship information of users is collected to generate an online social network. From the perspective of network topology,we propose node topological potential to characterize user's social influence.With this metric,we distinguish different social relations between users and find out those who really have influence on the target users.Tag recommendations are based on tagging history and the latent personalized preference learned from those who have most influence in user's social network.We evaluate our method on large scale real-world data.The experimental results demonstrate that our method can outperform the non-personalized global co-occurrence method and other two state-of-the-art personalized approaches using social networks.We also analyze the further usage of our approach for the cold-start problem of tag recommendation.

  4. Harvesting Intelligence in Multimedia Social Tagging Systems

    Science.gov (United States)

    Giannakidou, Eirini; Kaklidou, Foteini; Chatzilari, Elisavet; Kompatsiaris, Ioannis; Vakali, Athena

    As more people adopt tagging practices, social tagging systems tend to form rich knowledge repositories that enable the extraction of patterns reflecting the way content semantics is perceived by the web users. This is of particular importance, especially in the case of multimedia content, since the availability of such content in the web is very high and its efficient retrieval using textual annotations or content-based automatically extracted metadata still remains a challenge. It is argued that complementing multimedia analysis techniques with knowledge drawn from web social annotations may facilitate multimedia content management. This chapter focuses on analyzing tagging patterns and combining them with content feature extraction methods, generating, thus, intelligence from multimedia social tagging systems. Emphasis is placed on using all available "tracks" of knowledge, that is tag co-occurrence together with semantic relations among tags and low-level features of the content. Towards this direction, a survey on the theoretical background and the adopted practices for analysis of multimedia social content are presented. A case study from Flickr illustrates the efficiency of the proposed approach.

  5. A hypergraph model of social tagging networks

    Science.gov (United States)

    Zhang, Zi-Ke; Liu, Chuang

    2010-10-01

    The past few years have witnessed the great success of a new family of paradigms, so-called folksonomy, which allows users to freely associate tags with resources and efficiently manage them. In order to uncover the underlying structures and user behaviors in folksonomy, in this paper, we propose an evolutionary hypergraph model for explaining the emerging statistical properties. The present model introduces a novel mechanism that can not only assign tags to resources, but also retrieve resources via collaborative tags. We then compare the model with a real-world data set: Del.icio.us. Indeed, the present model shows considerable agreement with the empirical data in the following aspects: power-law hyperdegree distributions, negative correlation between clustering coefficients and hyperdegrees, and small average distances. Furthermore, the model indicates that most tagging behaviors are motivated by labeling tags on resources, and the tag plays a significant role in effectively retrieving interesting resources and making acquaintances with congenial friends. The proposed model may shed some light on the in-depth understanding of the structure and function of folksonomy.

  6. TagSmart: analysis and visualization for yeast mutant fitness data measured by tag microarrays

    Directory of Open Access Journals (Sweden)

    Xie Dan

    2007-04-01

    Full Text Available Abstract Background A nearly complete collection of gene-deletion mutants (96% of annotated open reading frames of the yeast Saccharomyces cerevisiae has been systematically constructed. Tag microarrays are widely used to measure the fitness of each mutant in a mutant mixture. The tag array experiments can have a complex experimental design, such as time course measurements and drug treatment with multiple dosages. Results TagSmart is a web application for analysis and visualization of Saccharomyces cerevisiae mutant fitness data measured by tag microarrays. It implements a robust statistical approach to assess the concentration differences among S. cerevisiae mutant strains. It also provides an interactive environment for data analysis and visualization. TagSmart has the following advantages over previously described analysis procedures: 1 it is user-friendly software rather than merely a description of analytical procedure; 2 It can handle complicated experimental designs, such as multiple time points and treatment with multiple dosages; 3 it has higher sensitivity and specificity; 4 It allows users to mask out "bad" tags in the analysis. Two biological tests were performed to illustrate the performance of TagSmart. First, we generated titration mixtures of mutant strains, in which the relative concentration of each strain was controlled. We used tag microarrays to measure the numbers of tag copies in each titration mixture. The data was analyzed with TagSmart and the result showed high precision and recall. Second, TagSmart was applied to a dataset in which heterozygous deletion strain mixture pools were treated with a new drug, Cincreasin. TagSmart identified 53 mutant strains as sensitive to Cincreasin treatment. We individually tested each identified mutant, and found 52 out of the 53 predicted mutants were indeed sensitive to Cincreasin. Conclusion TagSmart is provided "as is" to analyze tag array data produced by Affymetrix and Agilent

  7. The value of LibraryThing tags for academic libraries

    NARCIS (Netherlands)

    Voorbij, H.

    2012-01-01

    Purpose - The purpose of this paper is to determine the percentage of recently published books provided with tags drawn from LibraryThing for Libraries, the nature of these tags, the relation of the tags with keywords in the record and the percentage of records actually enhanced by tags.

  8. The value of LibraryThing tags for academic libraries

    NARCIS (Netherlands)

    Voorbij, H.

    2012-01-01

    Purpose - The purpose of this paper is to determine the percentage of recently published books provided with tags drawn from LibraryThing for Libraries, the nature of these tags, the relation of the tags with keywords in the record and the percentage of records actually enhanced by tags. Design/meth

  9. Modules for C-terminal epitope tagging of Tetrahymena genes

    Science.gov (United States)

    Kataoka, Kensuke; Schoeberl, Ursula E.; Mochizuki, Kazufumi

    2010-01-01

    Although epitope tagging has been widely used for analyzing protein function in many organisms, there are few genetic tools for epitope tagging in Tetrahymena. In this study, we describe several C-terminal epitope tagging modules that can be used to express tagged proteins in Tetrahymena cells by both plasmid- and PCR-based strategies. PMID:20624430

  10. Optimisation of a stirred bioreactor through the use of a novel holographic correlation velocimetry flow measurement technique.

    Directory of Open Access Journals (Sweden)

    Mohd-Zulhilmi Ismadi

    Full Text Available We describe a method for measuring three dimensional (3D velocity fields of a fluid at high speed, by combining a correlation-based approach with in-line holography. While this method utilizes tracer particles contained within the flow, our method does not require the holographic reconstruction of 3D images. The direct flow reconstruction approach developed here allows for measurements at seeding densities in excess of the allowable levels for techniques based on image or particle reconstruction, thus making it suited for biological flow measurement, such as the flow in bioreactor. We outline the theory behind our method, which we term Holographic Correlation Velocimetry (HCV, and subsequently apply it to both synthetic and laboratory data. Moreover, because the system is based on in-line holography, it is very efficient with regard to the use of light, as it does not rely on side scattering. This efficiency could be utilized to create a very high quality system at a modest cost. Alternatively, this efficiency makes the system appropriate for high-speed flows and low exposure times, which is essential for imaging dynamic systems.

  11. Light-field camera-based 3D volumetric particle image velocimetry with dense ray tracing reconstruction technique

    Science.gov (United States)

    Shi, Shengxian; Ding, Junfei; New, T. H.; Soria, Julio

    2017-07-01

    This paper presents a dense ray tracing reconstruction technique for a single light-field camera-based particle image velocimetry. The new approach pre-determines the location of a particle through inverse dense ray tracing and reconstructs the voxel value using multiplicative algebraic reconstruction technique (MART). Simulation studies were undertaken to identify the effects of iteration number, relaxation factor, particle density, voxel-pixel ratio and the effect of the velocity gradient on the performance of the proposed dense ray tracing-based MART method (DRT-MART). The results demonstrate that the DRT-MART method achieves higher reconstruction resolution at significantly better computational efficiency than the MART method (4-50 times faster). Both DRT-MART and MART approaches were applied to measure the velocity field of a low speed jet flow which revealed that for the same computational cost, the DRT-MART method accurately resolves the jet velocity field with improved precision, especially for the velocity component along the depth direction.

  12. Associated Particle Tagging (APT) in Magnetic Spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, David V.; Baciak, James E.; Stave, Sean C.; Chichester, David; Dale, Daniel; Kim, Yujong; Harmon, Frank

    2012-10-16

    Summary In Brief The Associated Particle Tagging (APT) project, a collaboration of Pacific Northwest National Laboratory (PNNL), Idaho National Laboratory (INL) and the Idaho State University (ISU)/Idaho Accelerator Center (IAC), has completed an exploratory study to assess the role of magnetic spectrometers as the linchpin technology in next-generation tagged-neutron and tagged-photon active interrogation (AI). The computational study considered two principle concepts: (1) the application of a solenoidal alpha-particle spectrometer to a next-generation, large-emittance neutron generator for use in the associated particle imaging technique, and (2) the application of tagged photon beams to the detection of fissile material via active interrogation. In both cases, a magnetic spectrometer momentum-analyzes charged particles (in the neutron case, alpha particles accompanying neutron generation in the D-T reaction; in the tagged photon case, post-bremsstrahlung electrons) to define kinematic properties of the relevant neutral interrogation probe particle (i.e. neutron or photon). The main conclusions of the study can be briefly summarized as follows: Neutron generator: • For the solenoidal spectrometer concept, magnetic field strengths of order 1 Tesla or greater are required to keep the transverse size of the spectrometer smaller than 1 meter. The notional magnetic spectrometer design evaluated in this feasibility study uses a 5-T magnetic field and a borehole radius of 18 cm. • The design shows a potential for 4.5 Sr tagged neutron solid angle, a factor of 4.5 larger than achievable with current API neutron-generator designs. • The potential angular resolution for such a tagged neutron beam can be less than 0.5o for modest Si-detector position resolution (3 mm). Further improvement in angular resolution can be made by using Si-detectors with better position resolution. • The report documents several features of a notional generator design incorporating the

  13. Analyzing Tag Distributions in Folksonomies for Resource Classification

    CERN Document Server

    Zubiaga, Arkaitz; Fresno, Víctor

    2012-01-01

    Recent research has shown the usefulness of social tags as a data source to feed resource classification. Little is known about the effect of settings on folksonomies created on social tagging systems. In this work, we consider the settings of social tagging systems to further understand tag distributions in folksonomies. We analyze in depth the tag distributions on three large-scale social tagging datasets, and analyze the effect on a resource classification task. To this end, we study the appropriateness of applying weighting schemes based on the well-known TF-IDF for resource classification. We show the great importance of settings as to altering tag distributions. Among those settings, tag suggestions produce very different folksonomies, which condition the success of the employed weighting schemes. Our findings and analyses are relevant for researchers studying tag-based resource classification, user behavior in social networks, the structure of folksonomies and tag distributions, as well as for develope...

  14. A brief examination of optical tagging technologies.

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, Mark R.; Cahill, Paul A. (Aspecular Optics, Dayton, OH); Drummond, Timothy J.; Wilcoxon, Jess Patrick

    2003-07-01

    Presented within this report are the results of a brief examination of optical tagging technologies funded by the Laboratory Directed Research and Development (LDRD) program at Sandia National Laboratories. The work was performed during the summer months of 2002 with total funding of $65k. The intent of the project was to briefly examine a broad range of approaches to optical tagging concentrating on the wavelength range between ultraviolet (UV) and the short wavelength infrared (SWIR, {lambda} < 2{micro}m). Tagging approaches considered include such things as simple combinations of reflective and absorptive materials closely spaced in wavelength to give a high contrast over a short range of wavelengths, rare-earth oxides in transparent binders to produce a narrow absorption line hyperspectral tag, and fluorescing materials such as phosphors, dies and chemically precipitated particles. One technical approach examined in slightly greater detail was the use of fluorescing nano particles of metals and semiconductor materials. The idea was to embed such nano particles in an oily film or transparent paint binder. When pumped with a SWIR laser such as that produced by laser diodes at {lambda}=1.54{micro}m, the particles would fluoresce at slightly longer wavelengths, thereby giving a unique signal. While it is believed that optical tags are important for military, intelligence and even law enforcement applications, as a business area, tags do not appear to represent a high on return investment. Other government agencies frequently shop for existing or mature tag technologies but rarely are interested enough to pay for development of an untried technical approach. It was hoped that through a relatively small investment of laboratory R&D funds, enough technologies could be identified that a potential customers requirements could be met with a minimum of additional development work. Only time will tell if this proves to be correct.

  15. Optical diagnostics for turbulent and multiphase flows: Particle image velocimetry and photorefractive optics

    Energy Technology Data Exchange (ETDEWEB)

    O`Hern, T.J.; Torczynski, J.R.; Shagam, R.N.; Blanchat, T.K.; Chu, T.Y.; Tassin-Leger, A.L.; Henderson, J.A.

    1997-01-01

    This report summarizes the work performed under the Sandia Laboratory Directed Research and Development (LDRD) project ``Optical Diagnostics for Turbulent and Multiphase Flows.`` Advanced optical diagnostics have been investigated and developed for flow field measurements, including capabilities for measurement in turbulent, multiphase, and heated flows. Particle Image Velocimetry (PIV) includes several techniques for measurement of instantaneous flow field velocities and associated turbulence quantities. Nonlinear photorefractive optical materials have been investigated for the possibility of measuring turbulence quantities (turbulent spectrum) more directly. The two-dimensional PIV techniques developed under this LDRD were shown to work well, and were compared with more traditional laser Doppler velocimetry (LDV). Three-dimensional PIV techniques were developed and tested, but due to several experimental difficulties were not as successful. The photorefractive techniques were tested, and both potential capabilities and possible problem areas were elucidated.

  16. Pulsed operation of high-power light emitting diodes for imaging flow velocimetry

    Science.gov (United States)

    Willert, C.; Stasicki, B.; Klinner, J.; Moessner, S.

    2010-07-01

    High-powered light emitting diodes (LED) are investigated for possible uses as light sources in flow diagnostics, in particular, as an alternative to laser-based illumination in particle imaging flow velocimetry in side-scatter imaging arrangements. Recent developments in solid state illumination resulted in mass-produced LEDs that provide average radiant power in excess of 10 W. By operating these LEDs with short duration, pulsed currents that are considerably beyond their continuous current damage threshold, light pulses can be generated that are sufficient to illuminate and image micron-sized particles in flow velocimetry. Time-resolved PIV measurements in water at a framing rate of 2kHz are presented. The feasibility of LED-based PIV measurements in air is also demonstrated.

  17. Tag and Neighbor based Recommender systems for Medical events

    DEFF Research Database (Denmark)

    Bayyapu, Karunakar Reddy; Dolog, Peter

    2010-01-01

    This paper presents an extension of a multifactor recommendation approach based on user tagging with term neighbours. Neighbours of words in tag vectors and documents provide for hitting larger set of documents and not only those matching with direct tag vectors or content of the documents. Tag...... in the situations where the quality of tags is lower. We discuss the approach on the examples from the existing Medworm system to indicate the usefulness of the approach....

  18. Tag and Neighbor based Recommender systems for Medical events

    DEFF Research Database (Denmark)

    Bayyapu, Karunakar Reddy; Dolog, Peter

    This paper presents an extension of a multifactor recommendation approach based on user tagging with term neighbours. Neighbours of words in tag vectors and documents provide for hitting larger set of documents and not only those matching with direct tag vectors or content of the documents. Tag...... in the situations where the quality of tags is lower. We discuss the approach on the examples from the existing Medworm system to indicate the usefulness of the approach....

  19. On the Analysis of Tag Questions in English Teaching

    Institute of Scientific and Technical Information of China (English)

    朱虹

    2013-01-01

    Tag question is often used in English conversation, but it is also a very complicated syntactic structure in English which becomes the difficulty of English learners. Tag question involves various grammatical factors. A full linguistic analysis of tag ques⁃tions includes the classification, construction and meanings of intonations of the tag questions in English. The study of tag ques⁃tion aims at providing substantial contribution to the teaching and learning of English syntax.

  20. Particle streak velocimetry-OCT (PSV-OCT): a novel method for multi-vector component velocimetry of microscale flow physiology (Conference Presentation)

    Science.gov (United States)

    Zhou, Kevin C.; Huang, Brendan K.; Gamm, Ute A.; Bhandari, Vineet; Khokha, Mustafa K.; Choma, Michael A.

    2016-03-01

    We present a new method for 2.5 and 3 vector component velocimetry. We call this method particle streak velocimetry OCT (PSV-OCT). PSV-OCT generates two-dimensional, 2.5 vector component (v_x,|v_y|,v_z) cross-sectional maps of microscale flow velocity (e.g. biological cilia-driven fluid flow). The enabling insight is that a tracer particle in sparsely-seeded fluid flow traces out streaks in (x,z,t)-space. The streak orientations in x-t and z-t yield v_x and v_z, respectively. The in-plane (x-z plane) residence time yields the out-of-plane speed |v_y|. Vector component values are generated by fitting streaks to a model of image formation. We demonstrate cross-sectional estimation of (v_x,|v_y|,v_z) in two important animal models in ciliary biology: Xenopus embryos (tadpoles) and mouse trachea. Further, by incorporation the assumption of incompressible flow into the estimation process, we are able to generate 3 vector component (v_x,v_y,v_z) estimates in three spatial dimensions from 2.5 vector component measurements taken in parallel OCT planes in 3D space.

  1. Particle tracking velocimetry and particle image velocimetry study of the slow motion of rough and smooth solid spheres in a yield-stress fluid.

    Science.gov (United States)

    Holenberg, Yulia; Lavrenteva, Olga M; Shavit, Uri; Nir, Avinoam

    2012-12-01

    We report experimental evidence of an effect opposite to the "solidification" of small bubbles in liquid where the surface can become immobile. Namely, it is demonstrated that smooth solid spheres falling in a yield-stress fluid under the action of gravity can behave similar to drops. Particle tracking velocimetry was used to determine the shape of the yielded region around solid spherical particles undergoing slow stationary motion in 0.07% w/w Carbopol gel due to gravity under creeping flow conditions. The flow field inside the yielded region was determined by particle image velocimetry. It was found that the shape of the yielded region and the flow field around slow-moving rough particles is similar to the published results of numerical simulations, whereas those around smooth spheres resemble the experimental results obtained for viscous drops. The effect was explained by a slip of the gel on the smooth surface. Most likely, the slip originated from seepage of clean water from the gel, forming a thin lubricating layer near the solid surface.

  2. Abnormal Doppler flow velocimetry in the growth restricted foetus as a predictor for necrotising enterocolitis.

    Directory of Open Access Journals (Sweden)

    Bhatt A

    2002-07-01

    Full Text Available BACKGROUND: Obstetric decision- making for the growth restricted foetus has to take into consideration the benefits and risks of waiting for pulmonary maturity and continued exposure to hostile intra-uterine environment. Necrotising Enterocolitis (NEC results from continued exposure to hostile environment and is an important cause of poor neonatal outcome. AIMS: To evaluate the predictive value of abnormal Doppler flow velocimetry of the foetal umbilical artery for NEC and neonatal mortality. SETTINGS AND DESIGN: A retrospective study carried out at a tertiary care centre for obstetric and neonatal care. MATERIALS AND METHOD: Seventy-seven neonates with birth weight less than 2000 gm, born over a period of 18 months were studied. These pregnancies were identified as having growth abnormalities of the foetus. Besides other tests of foetal well-being, they were also subjected to Doppler flow velocimetry of the foeto-placental vasculature. Obstetric outcome was evaluated with reference to period of gestation and route of delivery. The neonatal outcome was reviewed with reference to birth weight, Apgar scores and evidence of NEC. STATISTICAL ANALYSIS USED: Chi square test. RESULTS: In the group of patients with Absent or Reverse End Diastolic Frequencies (A/R EDF in the umbilical arteries, positive predictive value for NEC was 52.6%, (RR 30.2; OR 264. The mortality from NEC was 50%. When umbilical artery velocimetry did not show A/REDF, there were no cases of NEC or mortality. Abnormal umbilical or uterine artery flow increased the rate of caesarean section to 62.5% as compared to 17.6% in cases where umbilical artery flow was normal. CONCLUSION: In antenatally identified pregnancies at risk for foetal growth restriction, abnormal Doppler velocimetry in the form of A/REDF in the umbilical arteries is a useful guide to predict NEC and mortality in the early neonatal period.

  3. Particle image velocimetry of highly luminescent, pressurized combustion flows of aero engine combustors

    OpenAIRE

    Schroll, Michael; Klinner, Joachim; Lange, Lena; Willert, Christian

    2013-01-01

    This contribution describes recent efforts leading toward the successful application of particle image velocimetry (PIV) in highly luminescent flames avoiding saturation of the second frame of commonly available double shutter PIV cameras, which is usually inevitable when using their interline-transfer CCD sensors. Information on fuel placement, reaction zone and temperature field among other quantities can be provided by frequently used spectroscopic techniques. The velocity information is o...

  4. Pulsed operation of high power light emitting diodes for flow velocimetry

    OpenAIRE

    Willert, Christian; Mößner, Steffen; Klinner, Joachim

    2009-01-01

    High powered light emitting diodes (LED) are investigated for possible uses as light sources in flow diagnostics, in particular, as an alternative to laser-based illumination in particle imaging flow velocimetry. Recent developments in solid state illumination resulted in mass-produced LEDs that provide average radiant power in excess of 10 Watt. By operating these LEDs with short duration, pulsed currents that are considerably beyond their continuous current damage th...

  5. Pulsed operation of high-power light emitting diodes for imaging flow velocimetry

    OpenAIRE

    Willert, Christian; Stasicki, Boleslaw; Klinner, Joachim; Moessner, S.

    2010-01-01

    High-powered light emitting diodes (LED) are investigated for possible uses as light sources in flow diagnostics, in particular, as an alternative to laser-based illumination in particle imaging flow velocimetry in side-scatter imaging arrangements. Recent developments in solid state illumination resulted in mass-produced LEDs that provide average radiant power in excess of 10 W. By operating these LEDs with short duration, pulsed currents that are considerably beyond their continuous c...

  6. Characterization of acoustic streaming and heating using synchronized infrared thermography and particle image velocimetry.

    Science.gov (United States)

    Layman, Christopher N; Sou, In Mei; Bartak, Rico; Ray, Chittaranjan; Allen, John S

    2011-09-01

    Real-time measurements of acoustic streaming velocities and surface temperature fields using synchronized particle image velocimetry and infrared thermography are reported. Measurements were conducted using a 20 kHz Langevin type acoustic horn mounted vertically in a model sonochemical reactor of either degassed water or a glycerin-water mixture. These dissipative phenomena are found to be sensitive to small variations in the medium viscosity, and a correlation between the heat flux and vorticity was determined for unsteady convective heat transfer.

  7. In-cylinder Flow Characterisation of Heavy Duty Diesel Engines Using Combustion Image Velocimetry

    OpenAIRE

    Dembinski, Henrik

    2014-01-01

    In-cylinder flow in diesel engines has a large impact on combustion and emission formation. In this work, the flow is characterised with a new measurement method called combustion image velocimetry (CIV). This technique is used to explain how airflow introduced during induction affects soot emissions and interacts with injection pressures up to 2500 bar. The CIV measurements enable flow analysis during the combustion and post-oxidation phases. The flow velocities inside the cylinder of a heav...

  8. Laser Doppler velocimetry applied to the measurement of local and global wind

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, J.M.; Forrester, P.A. (Royal Signals and Radar Establishment, Malvern (GB))

    1989-01-01

    The analysis of radiation scattered from naturally occurring aerosols carried along by the wind provides a powerful tool for the study of wind structure and enables the air flow to be studied from a single, non-perturbing, measuring station. In this paper, we outline the current status of wind measurement from ground-based, air borne and space platforms. The potential for using Laser Doppler Velocimetry on a range of applications with wind turbine generators is discussed. (author).

  9. Identification of transmitter systems and learning tag molecules involved in behavioral tagging during memory formation.

    Science.gov (United States)

    Moncada, Diego; Ballarini, Fabricio; Martinez, María Cecilia; Frey, Julietta U; Viola, Haydee

    2011-08-02

    Long-term memory (LTM) consolidation requires the synthesis of plasticity-related proteins (PRPs). In addition, we have shown recently that LTM formation also requires the setting of a "learning tag" able to capture those PRPs. Weak training, which results only in short-term memory, can set a tag to use PRPs derived from a temporal-spatial closely related event to promote LTM formation. Here, we studied the involvement of glutamatergic, dopaminergic, and noradrenergic inputs on the setting of an inhibitory avoidance (IA) learning tag and the synthesis of PRPs. Rats explored an open field (PRP donor) followed by weak (tag inducer) or strong (tag inducer plus PRP donor) IA training. Throughout pharmacological interventions around open-field and/or IA sessions, we found that hippocampal dopamine D1/D5- and β-adrenergic receptors are specifically required to induce PRP synthesis. Moreover, activation of the glutamatergic NMDA receptors is required for setting the learning tags, and this machinery further required α-Ca(2+)/calmodulin-dependent protein kinase II and PKA but not ERK1/2 activity. Together, the present findings emphasize an essential role of the induction of PRPs and learning tags for LTM formation. The existence of only the PRP or the tag was insufficient for stabilization of the mnemonic trace.

  10. Tag4M, a Wi-Fi RFID Active Tag Optimized for Sensor Measurements

    OpenAIRE

    Folea, Silviu; Ghercioiu, Marius

    2010-01-01

    This presentation introduces a Wi-Fi tag named Tag4M. The novelty of the design is Wi-Fi with ultra-low power, in a very small package that is running on a battery for years and offers a platform for sensor measurements using the existing (Internet) network

  11. Extracting Usage Patterns and the Analysis of Tag Connection Dynamics within Collaborative Tagging Systems

    Directory of Open Access Journals (Sweden)

    Daniel MICAN

    2013-01-01

    Full Text Available Collaborative tagging has become a very popular way of annotation, thanks to the fact that any entity may be labeled by any individual based on his own reason. In this paper we present the results of the case study carried out on the basis of data gathered at different time intervals from the social tagging system developed and implemented on Întelepciune.ro. Analyzing collective data referring to the way in which community members associate different tags, we have observed that between tags, links are formed which become increasingly stable with the passing of time. Following the application of methodology specific to network analysis, we have managed to extract information referring to tag popularity, their influence within the network and the degree to which a tag depends upon another. As such, we have succeeded in determining different semantic structures within the collective tagging system and see their evolution at different stages in time. Furthermore, we have pictured the way in which tag rec-ommendations can be executed and that they can be integrated within recommendation sys-tems. Thus, we will be able to identify experts and trustworthy content based on different cat-egories of interest.

  12. Tag-to-Tag Interference Suppression Technique Based on Time Division for RFID

    Directory of Open Access Journals (Sweden)

    Grishma Khadka

    2017-01-01

    Full Text Available Radio-frequency identification (RFID is a tracking technology that enables immediate automatic object identification and rapid data sharing for a wide variety of modern applications using radio waves for data transmission from a tag to a reader. RFID is already well established in technical areas, and many companies have developed corresponding standards and measurement techniques. In the construction industry, effective monitoring of materials and equipment is an important task, and RFID helps to improve monitoring and controlling capabilities, in addition to enabling automation for construction projects. However, on construction sites, there are many tagged objects and multiple RFID tags that may interfere with each other’s communications. This reduces the reliability and efficiency of the RFID system. In this paper, we propose an anti-collision algorithm for communication between multiple tags and a reader. In order to suppress interference signals from multiple neighboring tags, the proposed algorithm employs the time-division (TD technique, where tags in the interrogation zone are assigned a specific time slot so that at every instance in time, a reader communicates with tags using the specific time slot. We present representative computer simulation examples to illustrate the performance of the proposed anti-collision technique for multiple RFID tags.

  13. Tag-to-Tag Interference Suppression Technique Based on Time Division for RFID

    Science.gov (United States)

    Khadka, Grishma; Hwang, Suk-Seung

    2017-01-01

    Radio-frequency identification (RFID) is a tracking technology that enables immediate automatic object identification and rapid data sharing for a wide variety of modern applications using radio waves for data transmission from a tag to a reader. RFID is already well established in technical areas, and many companies have developed corresponding standards and measurement techniques. In the construction industry, effective monitoring of materials and equipment is an important task, and RFID helps to improve monitoring and controlling capabilities, in addition to enabling automation for construction projects. However, on construction sites, there are many tagged objects and multiple RFID tags that may interfere with each other’s communications. This reduces the reliability and efficiency of the RFID system. In this paper, we propose an anti-collision algorithm for communication between multiple tags and a reader. In order to suppress interference signals from multiple neighboring tags, the proposed algorithm employs the time-division (TD) technique, where tags in the interrogation zone are assigned a specific time slot so that at every instance in time, a reader communicates with tags using the specific time slot. We present representative computer simulation examples to illustrate the performance of the proposed anti-collision technique for multiple RFID tags. PMID:28045440

  14. Two-wave photon Doppler velocimetry measurements in direct impact Hopkinson pressure bar experiments

    Science.gov (United States)

    Lea, Lewis J.; Jardine, Andrew P.

    2015-09-01

    Direct impact Hopkinson pressure bar systems offer many potential advantages over split Hopkinson pressure bars, including access to higher strain rates, higher strains for equivalent striker velocity and system length, lower dispersion and faster achievement of force equilibrium. Currently advantages are gained at a significant cost: the fact that input bar data is unavailable removes all information about the striker impacted specimen face, preventing the determination of force equilibrium, and requiring approximations to be made on the sample deformation history. Recently photon Doppler velocimetry methods have been developed, which can replace strain gauges on Hopkinson bars. In this paper we discuss an experimental method and complementary data analysis for using Doppler velocimetry to measure surface velocities of the striker and output bars in a direct impact bar experiment, allowing similar data to be recorded as in a split bar system, with the same level of convenience. We discuss extracting velocity and force measurements, and improving the accuracy and convenience of Doppler velocimetry on Hopkinson bars. Results obtained using the technique are compared to equivalent split bar tests, showing improved stress measurements for the lowest and highest strains.

  15. Weighted least-squares solver for determining pressure from particle image velocimetry data

    Science.gov (United States)

    de Kat, Roeland

    2016-11-01

    Currently, most approaches to determine pressure from particle image velocimetry data are Poisson approaches (e.g.) or multi-pass marching approaches (e.g.). However, these approaches deal with boundary conditions in their specific ways which cannot easily be changed-Poisson approaches enforce boundary conditions strongly, whereas multi-pass marching approaches enforce them weakly. Under certain conditions (depending on the certainty of the data or availability of reference data along the boundary) both types of boundary condition enforcement have to be used together to obtain the best result. In addition, neither of the approaches takes the certainty of the particle image velocimetry data (see e.g.) within the domain into account. Therefore, to address these shortcomings and improve upon current approaches, a new approach is proposed using weighted least-squares. The performance of this new approach is tested on synthetic and experimental particle image velocimetry data. Preliminary results show that a significant improvement can be made in determining pressure fields using the new approach. RdK is supported by a Leverhulme Trust Early Career Fellowship.

  16. [Measurement method of arterial shear stress of rats model based on ultrasonic particle imaging velocimetry].

    Science.gov (United States)

    Xhu, Yiheng; Qian, Ming; Niu, Lili; Zheng, Hairong; Lu, Guangwen

    2014-12-01

    The development and progression of atherosclerosis and thrombosis are closely related to changes of hemodynamics parameters. Ultrasonic pulse wave Doppler technique is normally used for noninvasively blood flow imaging. However, this technique only provides one-dimensional velocity and depends on the angle between the ultrasound beam and the local velocity vector. In this study, ultrasonic particle image velocimetry method was used to assess whole field hemodynamic changes in normal blood vessels. By using the polynomial fitting method, we investigated the velocity gradient and assessed the shear in different blood flow velocity of 10 healthy rats. It was found that using four polynomial fitting could result in optimal measurement results. The results obtained by ultrasonic particle image velocimetry accorded with the results obtained using Doppler technique. The statistical average of cyclical vessel wall shear stress was positively related to the locational mean velocity. It is proven that ultrasonic particle image velocimetry method could be used to assess directly the real-time whole field hemodynamic changes in blood vessels and was non-invasively, and should be a good prosperous technique for monitoring complex blood flow in stenotic ar- teries.

  17. Two-wave photon Doppler velocimetry measurements in direct impact Hopkinson pressure bar experiments

    Directory of Open Access Journals (Sweden)

    Lea Lewis J.

    2015-01-01

    Full Text Available Direct impact Hopkinson pressure bar systems offer many potential advantages over split Hopkinson pressure bars, including access to higher strain rates, higher strains for equivalent striker velocity and system length, lower dispersion and faster achievement of force equilibrium. Currently advantages are gained at a significant cost: the fact that input bar data is unavailable removes all information about the striker impacted specimen face, preventing the determination of force equilibrium, and requiring approximations to be made on the sample deformation history. Recently photon Doppler velocimetry methods have been developed, which can replace strain gauges on Hopkinson bars. In this paper we discuss an experimental method and complementary data analysis for using Doppler velocimetry to measure surface velocities of the striker and output bars in a direct impact bar experiment, allowing similar data to be recorded as in a split bar system, with the same level of convenience. We discuss extracting velocity and force measurements, and improving the accuracy and convenience of Doppler velocimetry on Hopkinson bars. Results obtained using the technique are compared to equivalent split bar tests, showing improved stress measurements for the lowest and highest strains.

  18. Higher-Order Markov Tag-Topic Models for Tagged Documents and Images

    CERN Document Server

    Zeng, Jia; Cheung, William K; Li, Chun-Hung

    2011-01-01

    This paper studies the topic modeling problem of tagged documents and images. Higher-order relations among tagged documents and images are major and ubiquitous characteristics, and play positive roles in extracting reliable and interpretable topics. In this paper, we propose the tag-topic models (TTM) to depict such higher-order topic structural dependencies within the Markov random field (MRF) framework. First, we use the novel factor graph representation of latent Dirichlet allocation (LDA)-based topic models from the MRF perspective, and present an efficient loopy belief propagation (BP) algorithm for approximate inference and parameter estimation. Second, we propose the factor hypergraph representation of TTM, and focus on both pairwise and higher-order relation modeling among tagged documents and images. Efficient loopy BP algorithm is developed to learn TTM, which encourages the topic labeling smoothness among tagged documents and images. Extensive experimental results confirm the incorporation of highe...

  19. Fast and scalable image auto-tagging

    CERN Document Server

    Frejaville, Camille; Lepetit, Vincent

    Inside Invenio, the web-based integrated system for handling digital libraries developed at CERN, there is a media module, enabling users to upload photos and videos. Especially in CDS, the Invenio instance used at CERN, people use this digital library to upload pictures of official events that took place at CERN. However, so far, there was no way of tagging what’s inside these photos. This project is meant to solve the problem of tagging persons in a photo in an easy and fast way. First, by implementing a complete tagging interface that allows the user to square parts of the photo, resize them, move them and give them a name. Second, by running face detection so that squares already appear on faces and the user just has to fill the title field. Finally, by running a face recognition system that learned from previous tags created by users. In this report, we will show how we implemented the tagging interface, how we improved the existing face detector to make it more efficient, which face detection methods ...

  20. Tagging: An Organization Scheme for the Internet

    Directory of Open Access Journals (Sweden)

    Marijke A. Visser

    2010-03-01

    Full Text Available How should the information on the Internet be organized? This question and the possible solutions spark debates among people concerned with how we identify, classify, and retrieve Internet content. This paper discusses the benefits and the controversies of using a tagging system to organize Internet resources. Tagging refers to a classification system where individual Internet users apply labels, or tags, to digital resources. Tagging increased in popularity with the advent of Web 2.0 applications that encourage interaction among users. As more information is available digitally, the challenge to find an organizational system scalable to the Internet will continue to require forward thinking. Trained to ensure access to a range of informational resources, librarians need to be concerned with access to Internet content. Librarians can play a pivotal role by advocating for a system that supports the user at the moment of need. Tagging may just be the necessary system.

  1. Turbulence measurements in a transonic boundary layer and free-shear flow using laser velocimetry and hot-wire anemometry techniques

    Science.gov (United States)

    Johnson, D. A.; Rose, W. C.

    1976-01-01

    Quantitative measurements of the turbulence fluctuations in velocity and mass flux have been obtained in Mach 0.6 and 0.8 turbulent boundary layer and free-shear layer flows by laser velocimetry and hot-wire anemometry techniques. To evaluate the effects of compressibility, these transonic data are compared to available incompressible and supersonic results. Based on some simplifying assumptions, estimates of the rms density fluctuations are made for which error bounds are given. In addition to these fluctuation data, the compressible mean velocity data obtained with the laser velocimeter are presented and compared to pitot tube results. The investigation was conducted in the Ames 6- by 6-Foot Supersonic Wind Tunnel at free-stream Mach numbers of 0.6 and 0.8 for a unit Reynolds number of about 10,000,000 per meter.

  2. Improved Satellite-Monitored Radio Tags for Large Whales: Dependable ARGOS Location-Only Tags and a GPS-Linked Tag to Reveal 3-Dimensional Body-Orientation and Surface Movements

    Science.gov (United States)

    2012-09-30

    Australia with humpback whales using industry seismic sources RELATED PROJECTS Additional taggings of Pacific Coast Feeding Group gray whales will...will also allow us to evaluate how consistent roles are in groups of foraging sperm whales , the way humpbacks seem to be during coordinated bubble...net feeding . We will also be able to determine if all whales in an affiliate group have the same relative response to variable prey densities (i.e

  3. Scanning tomographic particle image velocimetry applied to a turbulent jet

    KAUST Repository

    Casey, T. A.

    2013-02-21

    We introduce a modified tomographic PIV technique using four high-speed video cameras and a scanning pulsed laser-volume. By rapidly illuminating adjacent subvolumes onto separate video frames, we can resolve a larger total volume of velocity vectors, while retaining good spatial resolution. We demonstrate this technique by performing time-resolved measurements of the turbulent structure of a round jet, using up to 9 adjacent volume slices. In essence this technique resolves more velocity planes in the depth direction by maintaining optimal particle image density and limiting the number of ghost particles. The total measurement volumes contain between 1 ×106 and 3 ×106 velocity vectors calculated from up to 1500 reconstructed depthwise image planes, showing time-resolved evolution of the large-scale vortical structures for a turbulent jet of Re up to 10 000.

  4. Passive UHF RFID Tag for Multispectral Assessment

    Science.gov (United States)

    Escobedo, Pablo; Carvajal, Miguel A.; Capitán-Vallvey, Luis F.; Fernández-Salmerón, José; Martínez-Olmos, Antonio; Palma, Alberto J.

    2016-01-01

    This work presents the design, fabrication, and characterization of a passive printed radiofrequency identification tag in the ultra-high-frequency band with multiple optical sensing capabilities. This tag includes five photodiodes to cover a wide spectral range from near-infrared to visible and ultraviolet spectral regions. The tag antenna and circuit connections have been screen-printed on a flexible polymeric substrate. An ultra-low-power microcontroller-based switch has been included to measure the five magnitudes issuing from the optical sensors, providing a spectral fingerprint of the incident electromagnetic radiation from ultraviolet to infrared, without requiring energy from a battery. The normalization procedure has been designed applying illuminants, and the entire system was tested by measuring cards from a colour chart and sensing fruit ripening. PMID:27428973

  5. Tagging and Morphological Disambiguation of Turkish Text

    CERN Document Server

    Oflazer, K; Oflazer, Kemal; Kuruoz, Ilker

    1994-01-01

    Automatic text tagging is an important component in higher level analysis of text corpora, and its output can be used in many natural language processing applications. In languages like Turkish or Finnish, with agglutinative morphology, morphological disambiguation is a very crucial process in tagging, as the structures of many lexical forms are morphologically ambiguous. This paper describes a POS tagger for Turkish text based on a full-scale two-level specification of Turkish morphology that is based on a lexicon of about 24,000 root words. This is augmented with a multi-word and idiomatic construct recognizer, and most importantly morphological disambiguator based on local neighborhood constraints, heuristics and limited amount of statistical information. The tagger also has functionality for statistics compilation and fine tuning of the morphological analyzer, such as logging erroneous morphological parses, commonly used roots, etc. Preliminary results indicate that the tagger can tag about 98-99\\% of the...

  6. Passive UHF RFID Tag for Multispectral Assessment

    Directory of Open Access Journals (Sweden)

    Pablo Escobedo

    2016-07-01

    Full Text Available This work presents the design, fabrication, and characterization of a passive printed radiofrequency identification tag in the ultra-high-frequency band with multiple optical sensing capabilities. This tag includes five photodiodes to cover a wide spectral range from near-infrared to visible and ultraviolet spectral regions. The tag antenna and circuit connections have been screen-printed on a flexible polymeric substrate. An ultra-low-power microcontroller-based switch has been included to measure the five magnitudes issuing from the optical sensors, providing a spectral fingerprint of the incident electromagnetic radiation from ultraviolet to infrared, without requiring energy from a battery. The normalization procedure has been designed applying illuminants, and the entire system was tested by measuring cards from a colour chart and sensing fruit ripening.

  7. Passive UHF RFID Tag for Multispectral Assessment.

    Science.gov (United States)

    Escobedo, Pablo; Carvajal, Miguel A; Capitán-Vallvey, Luis F; Fernández-Salmerón, José; Martínez-Olmos, Antonio; Palma, Alberto J

    2016-07-14

    This work presents the design, fabrication, and characterization of a passive printed radiofrequency identification tag in the ultra-high-frequency band with multiple optical sensing capabilities. This tag includes five photodiodes to cover a wide spectral range from near-infrared to visible and ultraviolet spectral regions. The tag antenna and circuit connections have been screen-printed on a flexible polymeric substrate. An ultra-low-power microcontroller-based switch has been included to measure the five magnitudes issuing from the optical sensors, providing a spectral fingerprint of the incident electromagnetic radiation from ultraviolet to infrared, without requiring energy from a battery. The normalization procedure has been designed applying illuminants, and the entire system was tested by measuring cards from a colour chart and sensing fruit ripening.

  8. A Privacy Model for RFID Tag Ownership Transfer

    Directory of Open Access Journals (Sweden)

    Xingchun Yang

    2017-01-01

    Full Text Available The ownership of RFID tag is often transferred from one owner to another in its life cycle. To address the privacy problem caused by tag ownership transfer, we propose a tag privacy model which captures the adversary’s abilities to get secret information inside readers, to corrupt tags, to authenticate tags, and to observe tag ownership transfer processes. This model gives formal definitions for tag forward privacy and backward privacy and can be used to measure the privacy property of tag ownership transfer scheme. We also present a tag ownership transfer scheme, which is privacy-preserving under the proposed model and satisfies the other common security requirements, in addition to achieving better performance.

  9. Statistical Function Tagging and Grammatical Relations of Myanmar Sentences

    CERN Document Server

    Thant, Win Win; Thein, Ni Lar

    2012-01-01

    This paper describes a context free grammar (CFG) based grammatical relations for Myanmar sentences which combine corpus-based function tagging system. Part of the challenge of statistical function tagging for Myanmar sentences comes from the fact that Myanmar has free-phrase-order and a complex morphological system. Function tagging is a pre-processing step to show grammatical relations of Myanmar sentences. In the task of function tagging, which tags the function of Myanmar sentences with correct segmentation, POS (part-of-speech) tagging and chunking information, we use Naive Bayesian theory to disambiguate the possible function tags of a word. We apply context free grammar (CFG) to find out the grammatical relations of the function tags. We also create a functional annotated tagged corpus for Myanmar and propose the grammar rules for Myanmar sentences. Experiments show that our analysis achieves a good result with simple sentences and complex sentences.

  10. Measurement of tag confidence in user generated contents retrieval

    Science.gov (United States)

    Lee, Sihyoung; Min, Hyun-Seok; Lee, Young Bok; Ro, Yong Man

    2009-01-01

    As online image sharing services are becoming popular, the importance of correctly annotated tags is being emphasized for precise search and retrieval. Tags created by user along with user-generated contents (UGC) are often ambiguous due to the fact that some tags are highly subjective and visually unrelated to the image. They cause unwanted results to users when image search engines rely on tags. In this paper, we propose a method of measuring tag confidence so that one can differentiate confidence tags from noisy tags. The proposed tag confidence is measured from visual semantics of the image. To verify the usefulness of the proposed method, experiments were performed with UGC database from social network sites. Experimental results showed that the image retrieval performance with confidence tags was increased.

  11. Top tagging with deep neural networks [Vidyo

    CERN Document Server

    CERN. Geneva

    2017-01-01

    Recent literature on deep neural networks for top tagging has focussed on image based techniques or multivariate approaches using high level jet substructure variables. Here, we take a sequential approach to this task by using anordered sequence of energy deposits as training inputs. Unlike previous approaches, this strategy does not result in a loss of information during pixelization or the calculation of high level features. We also propose new preprocessing methods that do not alter key physical quantities such as jet mass. We compare the performance of this approach to standard tagging techniques and present results evaluating the robustness of the neural network to pileup.

  12. Flavor tagging with muons at SLAC

    Science.gov (United States)

    Prepost, R.

    1984-05-01

    Identification of muons in hadronic events from e+e- annihilation observed in the MAC detector at PEP at √s=29 GeV provides flavor tagging of heavy quark mesons. A sample enriched in events from bb production is obtained and the b quark fragmentation function is determined. The b quark is found to fragment predominantly with high values of z, with =0.8+/-0.1 and to have an overall semileptonic branching ratio to muons of (15.5+5.4-2.9)%. The sample also provides flavor tagged hadronic jets. Invariant mass and charged multiplicity distributions are presented.

  13. B mixing and flavor tagging at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Russ, James S.; /Carnegie Mellon U.

    2004-12-01

    The CDF Collaboration has made a preliminary measurement of B{sub d} mixing as a first step toward measuring mixing in the B{sub s} system. Flavor tagging using opposite-side jets and muons as well as same-side tagging schemes have been applied. Results agree well with precise results from the B-factories. They use these results to estimate CDF's B{sub s} mixing range using the present data set ({approx} 250 pb{sup -1}) and extrapolate to the potential from larger data sets in future running.

  14. Lightweight Cryptography for Passive RFID Tags

    DEFF Research Database (Denmark)

    David, Mathieu

    2012-01-01

    among the smallest in the published literature and aims at being implemented on printed electronics RFID tags. Then, we compare different cryptographic primitives based on their key parameters: throughput, area, power consumption and level of security. Our main concern is the integrability...... of an integrator for a particular application. Finally, we conclude that the research for finding robust cryptographic primitive in the branch of lightweight cryptography still has some nice days ahead, and that providing a secure cryptosystem for printed electronics RFID tags remains an open research topic....

  15. Passive micromechanical tags. An investigation into writing information at nanometer resolution on micrometer size objects

    Energy Technology Data Exchange (ETDEWEB)

    Schmieder, R.W.; Bastasz, R.J.

    1995-01-01

    The authors have completed a 3-year study of the technology related to the development of micron-sized passive micromechanical tags. The project was motivated by the discovery in 1990 by the present authors that low energy, high charge state ions (e.g., Xe{sup +44}) can produce nanometer-size damage sites on solid surfaces, and the realization that a pattern of these sites represents information. It was envisioned that extremely small, chemically inert, mechanical tags carrying a large label could be fabricated for a variety of applications, including tracking of controlled substances, document verification, process control, research, and engineering. Potential applications exist in the data storage, chemical, food, security, and other industries. The goals of this project were fully accomplished, and they are fully documented here. The work was both experimental and developmental. Most of the experimental effort was a search for appropriate tag materials. Several good materials were found, and the upper limits of information density were determined (ca. 10{sup 12} bit/cm{sup 2}). Most of the developmental work involved inventing systems and strategies for using these tags, and compiling available technologies for implementing them. The technology provided herein is application-specific: first, the application must be specified, then the tag can be developed for it. The project was not intended to develop a single tag for a single application or for all possible applications. Rather, it was meant to provide the enabling technology for fabricating tags for a range of applications. The results of this project provide sufficient information to proceed directly with such development.

  16. Photon-tagged and B-meson-tagged b-jet production at the LHC

    Directory of Open Access Journals (Sweden)

    Jinrui Huang

    2015-11-01

    Full Text Available Tagged jet measurements in high energy hadronic and nuclear reactions provide constraints on the energy and parton flavor origin of the parton shower that recoils against the tagging particle. Such additional insight can be especially beneficial in illuminating the mechanisms of heavy flavor production in proton–proton collisions at the LHC and their modification in the heavy ion environment, which are not fully understood. With this motivation, we present theoretical results for isolated-photon-tagged and B-meson-tagged b-jet production at sNN=5.1 TeV for comparison to the upcoming lead–lead data. We find that photon-tagged b-jets exhibit smaller momentum imbalance shift in nuclear matter, and correspondingly smaller energy loss, than photon-tagged light flavor jets. Our results show that B-meson tagging is most effective in ensuring that the dominant fraction of recoiling jets originate from prompt b-quarks. Interestingly, in this channel the large suppression of the cross section is not accompanied by a significant momentum imbalance shift.

  17. Identification of transmitter systems and learning tag molecules involved in behavioral tagging during memory formation

    Science.gov (United States)

    Moncada, Diego; Ballarini, Fabricio; Martinez, María Cecilia; Frey, Julietta U.; Viola, Haydee

    2011-01-01

    Long-term memory (LTM) consolidation requires the synthesis of plasticity-related proteins (PRPs). In addition, we have shown recently that LTM formation also requires the setting of a “learning tag” able to capture those PRPs. Weak training, which results only in short-term memory, can set a tag to use PRPs derived from a temporal-spatial closely related event to promote LTM formation. Here, we studied the involvement of glutamatergic, dopaminergic, and noradrenergic inputs on the setting of an inhibitory avoidance (IA) learning tag and the synthesis of PRPs. Rats explored an open field (PRP donor) followed by weak (tag inducer) or strong (tag inducer plus PRP donor) IA training. Throughout pharmacological interventions around open-field and/or IA sessions, we found that hippocampal dopamine D1/D5- and β-adrenergic receptors are specifically required to induce PRP synthesis. Moreover, activation of the glutamatergic NMDA receptors is required for setting the learning tags, and this machinery further required α-Ca2+/calmodulin-dependent protein kinase II and PKA but not ERK1/2 activity. Together, the present findings emphasize an essential role of the induction of PRPs and learning tags for LTM formation. The existence of only the PRP or the tag was insufficient for stabilization of the mnemonic trace. PMID:21768371

  18. Seamless gene tagging by endonuclease-driven homologous recombination.

    Directory of Open Access Journals (Sweden)

    Anton Khmelinskii

    Full Text Available Gene tagging facilitates systematic genomic and proteomic analyses but chromosomal tagging typically disrupts gene regulatory sequences. Here we describe a seamless gene tagging approach that preserves endogenous gene regulation and is potentially applicable in any species with efficient DNA double-strand break repair by homologous recombination. We implement seamless tagging in Saccharomyces cerevisiae and demonstrate its application for protein tagging while preserving simultaneously upstream and downstream gene regulatory elements. Seamless tagging is compatible with high-throughput strain construction using synthetic genetic arrays (SGA, enables functional analysis of transcription antisense to open reading frames and should facilitate systematic and minimally-invasive analysis of gene functions.

  19. Evaluation of Intercontinental Transport of Ozone Using Full-tagged, Tagged-N and Sensitivity Methods

    Science.gov (United States)

    Guo, Y.; Liu, J.; Mauzerall, D. L.; Emmons, L. K.; Horowitz, L. W.; Fan, S.; Li, X.; Tao, S.

    2014-12-01

    Long-range transport of ozone is of great concern, yet the source-receptor relationships derived previously depend strongly on the source attribution techniques used. Here we describe a new tagged ozone mechanism (full-tagged), the design of which seeks to take into account the combined effects of emissions of ozone precursors, CO, NOx and VOCs, from a particular source, while keeping the current state of chemical equilibrium unchanged. We label emissions from the target source (A) and background (B). When two species from A and B sources react with each other, half of the resulting products are labeled A, and half B. Thus the impact of a given source on downwind regions is recorded through tagged chemistry. We then incorporate this mechanism into the Model for Ozone and Related chemical Tracers (MOZART-4) to examine the impact of anthropogenic emissions within North America, Europe, East Asia and South Asia on ground-level ozone downwind of source regions during 1999-2000. We compare our results with two previously used methods -- the sensitivity and tagged-N approaches. The ozone attributed to a given source by the full-tagged method is more widely distributed spatially, but has weaker seasonal variability than that estimated by the other methods. On a seasonal basis, for most source/receptor pairs, the full-tagged method estimates the largest amount of tagged ozone, followed by the sensitivity and tagged-N methods. In terms of trans-Pacific influence of ozone pollution, the full-tagged method estimates the strongest impact of East Asian (EA) emissions on the western U.S. (WUS) in MAM and JJA (~3 ppbv), which is substantially different in magnitude and seasonality from tagged-N and sensitivity studies. This difference results from the full-tagged method accounting for the maintenance of peroxy radicals (e.g., CH3O2, CH3CO3, and HO2), in addition to NOy, as effective reservoirs of EA source impact across the Pacific, allowing for a significant contribution to

  20. Orthogonal frequency coding for SAW tagging and sensors.

    Science.gov (United States)

    Puccio, Derek; Malocha, Donald C; Saldanha, Nancy; Gallagher, Daniel R; Hines, Jacqueline H

    2006-02-01

    Surface acoustic wave (SAW)-based sensors can offer wireless, passive operation in numerous environments, and various device embodiments are used for retrieval of the sensed data information. Single sensor systems typically can use a single carrier frequency and a simple device embodiment because tagging is not required. In a multisensor environment, it is necessary to both identify the sensor and retrieve the sensed information. This paper presents the concept of orthogonal frequency coding (OFC) for applications to SAW sensor technology. The OFC offers all advantages inherent to spread spectrum communications, including enhanced processing gain and lower interrogation power spectral density (PSD). It is shown that the time ambiguity in the OFC compressed pulse is significantly reduced as compared with a single frequency tag having the same code length, and additional coding can be added using a pseudo-noise (PN) sequence. The OFC approach is general and should be applicable to many differing SAW sensors for temperature, pressure, liquid, gases, etc. Device embodiments are shown, and a potential transceiver is described. Measured device results are presented and compared with coupling of modes (COM) model predictions to demonstrate performance. Devices then are used in computer simulations of the proposed transceiver design, and the results of an OFC sensor system are discussed.

  1. Femtosecond Laser Tagging Characterization of a Sweeping Jet Actuator Operating in the Compressible Regime

    Science.gov (United States)

    Peters, Christopher J.; Miles, Richard B.; Burns, Ross A.; Bathel, Brett F.; Jones, Gregory S.; Danehy, Paul M.

    2016-01-01

    A sweeping jet (SWJ) actuator operating over a range of nozzle pressure ratios (NPRs) was characterized with femtosecond laser electronic excitation tagging (FLEET), single hot-wire anemometry (HWA) and high-speed/phase-averaged schlieren. FLEET velocimetry was successfully demonstrated in a highly unsteady, oscillatory flow containing subsonic through supersonic velocities. Qualitative comparisons between FLEET and HWA (which measured mass flux since the flow was compressible) showed relatively good agreement in the external flow profiles. The spreading rate was found to vary from 0.5 to 1.2 depending on the pressure ratio. The precision of FLEET velocity measurements in the external flow field was poorer (is approximately equal to 25 m/s) than reported in a previous study due to the use of relatively low laser fluences, impacting the velocity fluctuation measurements. FLEET enabled velocity measurements inside the device and showed that choking likely occurred for NPR = 2.0, and no internal shockwaves were present. Qualitative oxygen concentration measurements using FLEET were explored in an effort to gauge the jet's mixing with the ambient. The jet was shown to mix well within roughly four throat diameters and mix fully within roughly eight throat diameters. Schlieren provided visualization of the internal and external flow fields and showed that the qualitative structure of the internal flow does not vary with pressure ratio and the sweeping mechanism observed for incompressible NPRs also probably holds for compressible NPRs.

  2. Purification of His-Tagged Proteins.

    Science.gov (United States)

    Spriestersbach, Anne; Kubicek, Jan; Schäfer, Frank; Block, Helena; Maertens, Barbara

    2015-01-01

    Ni-NTA affinity purification of His-tagged proteins is a bind-wash-elute procedure that can be performed under native or denaturing conditions. Here, protocols for purification of His-tagged proteins under native, as well as under denaturing conditions, are given. The choice whether to purify the target protein under native or denaturing conditions depends on protein location and solubility, the accessibility of the His tag, and the desired downstream application. His-tagged proteins can be purified by a single-step affinity chromatography, namely immobilized metal ion affinity chromatography (IMAC), which is commercially available in different kinds of formats, Ni-NTA matrices being the most widely used. The provided protocols describe protein purification in the batch binding mode and apply gravity-assisted flow in disposable columns; this procedure is simple to conduct and extremely robust. IMAC purification can equally be performed in prepacked columns using FPLC or other liquid chromatography instrumentation, or using magnetic bead-based methods (Block et al., 2009).

  3. Imaging mass spectrometer with mass tags

    Science.gov (United States)

    Felton, James S.; Wu, Kuang Jen J.; Knize, Mark G.; Kulp, Kristen S.; Gray, Joe W.

    2013-01-29

    A method of analyzing biological material by exposing the biological material to a recognition element, that is coupled to a mass tag element, directing an ion beam of a mass spectrometer to the biological material, interrogating at least one region of interest area from the biological material and producing data, and distributing the data in plots.

  4. Top Tagging by Deep Learning Algorithm

    CERN Document Server

    Akil, Ali

    2015-01-01

    In this report I will show the application of a deep learning algorithm on a Monte Carlo simulation sample to test its performance in tagging hadronic decays of boosted top quarks and compare what we get with the results of the application of some other algorithms.

  5. Lifetime Based b-tagging with CMS

    CERN Document Server

    Segneri, Gabriele

    2002-01-01

    This paper provides a review of the main algorithms for inclusive b-tagging based on track impact parameter and secondary vertices. The performance of these algorithms is investigated for jets in different E_T and eta intervals and results are compared. The ORCA framework and the base 3-pixel layer Tracker geometry are used in these studies.

  6. Novel and efficient tag SNPs selection algorithms.

    Science.gov (United States)

    Chen, Wen-Pei; Hung, Che-Lun; Tsai, Suh-Jen Jane; Lin, Yaw-Ling

    2014-01-01

    SNPs are the most abundant forms of genetic variations amongst species; the association studies between complex diseases and SNPs or haplotypes have received great attention. However, these studies are restricted by the cost of genotyping all SNPs; thus, it is necessary to find smaller subsets, or tag SNPs, representing the rest of the SNPs. In fact, the existing tag SNP selection algorithms are notoriously time-consuming. An efficient algorithm for tag SNP selection was presented, which was applied to analyze the HapMap YRI data. The experimental results show that the proposed algorithm can achieve better performance than the existing tag SNP selection algorithms; in most cases, this proposed algorithm is at least ten times faster than the existing methods. In many cases, when the redundant ratio of the block is high, the proposed algorithm can even be thousands times faster than the previously known methods. Tools and web services for haplotype block analysis integrated by hadoop MapReduce framework are also developed using the proposed algorithm as computation kernels.

  7. Automated Data Tagging in the HLA

    Science.gov (United States)

    Gaffney, N. I.; Miller, W. W.

    2008-08-01

    One of the more powerful and popular forms of data organization implemented in most popular information sharing web applications is data tagging. With a rich user base from which to gather and digest tags, many interesting and often unanticipated yet very useful associations are revealed. With regard to an existing information, the astronomical community has a rich pool of existing digitally stored and searchable data than any of the currently popular web community, such as You Tube or My Space, had when they started. In initial experiments with the search engine for the Hubble Legacy Archive, we have created a simple yet powerful scheme by which the information from a footprint service, the NED and SIMBAD catalog services, and the ADS abstracts and keywords can be used to initially tag data with standard keywords. By then ingesting this into a public ally available information search engine, such as Apache Lucene, one can create a simple and powerful data tag search engine and association system. By then augmenting this with user provided keys and usage pattern analysis, one can produce a powerful modern data mining system for any astronomical data warehouse.

  8. Analysis of Seed-expressed Sequence Tags in Triticum aestivum

    Institute of Scientific and Technical Information of China (English)

    LIJia-Rui; WANGFang; ZHAOXiang-Yu; DONGYu-Xiu; ZHANGLi-Yuan; ZHANGXian-Sheng

    2004-01-01

    To isolate seed-expressed sequences, a cDNA library was constructed using wheat ( Triticumaest/vum L) seed tissues at 12 d after pollination. Plasmid DNAs of 10 000 clones randomly picked out fromthe library were prepared. The preparation of high density filters were made with the Biomek 2000 HDRTsystem, and then hybridized separately with three probes prepared by reverse transcription of RNA ofunpollinated ovary, embryo and endosperm. Based on the hybridization results, 800 clones expressed inembryo and/or endosperm were chosen for further analysis of expressed sequence tags (ESTs). Finally,216 different genes were identified preliminarily. Of them, 24 (11.5%) were considered identical to knownwheat genes, 122 (56%) were identified as putative new plant genes which may be involved in seed storageproteins, biochemical metabolisms, development, and other biological processes of seeds, while 70 (32.5%)sequence identities could not be determined.

  9. Laboratory observations of sediment transport using combined particle image and tracking velocimetry (Conference Presentation)

    Science.gov (United States)

    Frank, Donya; Calantoni, Joseph

    2017-05-01

    Improved understanding of coastal hydrodynamics and morphology will lead to more effective mitigation measures that reduce fatalities and property damage caused by natural disasters such as hurricanes. We investigated sediment transport under oscillatory flow over flat and rippled beds with phase-separated stereoscopic Particle Image Velocimetry (PIV). Standard PIV techniques severely limit measurements at the fluid-sediment interface and do not allow for the observation of separate phases in multi-phase flow (e.g. sand grains in water). We have implemented phase-separated Particle Image Velocimetry by adding fluorescent tracer particles to the fluid in order to observe fluid flow and sediment transport simultaneously. While sand grains scatter 532 nm wavelength laser light, the fluorescent particles absorb 532 nm laser light and re-emit light at a wavelength of 584 nm. Optical long-pass filters with a cut-on wavelength of 550 nm were installed on two cameras configured to perform stereoscopic PIV to capture only the light emitted by the fluorescent tracer particles. A third high-speed camera was used to capture the light scattered by the sand grains allowing for sediment particle tracking via particle tracking velocimetry (PTV). Together, these overlapping, simultaneously recorded images provided sediment particle and fluid velocities at high temporal and spatial resolution (100 Hz sampling with 0.8 mm vector spacing for the 2D-3C fluid velocity field). Measurements were made under a wide range of oscillatory flows over flat and rippled sand beds. The set of observations allow for the investigation of the relative importance of pressure gradients and shear stresses on sediment transport.

  10. Inntags: small self-structured epitopes for innocuous protein tagging.

    Science.gov (United States)

    Georgieva, Maya V; Yahya, Galal; Codó, Laia; Ortiz, Raúl; Teixidó, Laura; Claros, José; Jara, Ricardo; Jara, Mònica; Iborra, Antoni; Gelpí, Josep Lluís; Gallego, Carme; Orozco, Modesto; Aldea, Martí

    2015-10-01

    Protein tagging is widely used in approaches ranging from affinity purification to fluorescence-based detection in live cells. However, an intrinsic limitation of tagging is that the native function of the protein may be compromised or even abolished by the presence of the tag. Here we describe and characterize a set of small, innocuous protein tags (inntags) that we anticipate will find application in a variety of biological techniques.

  11. A synchronized particle image velocimetry and infrared thermography technique applied to an acoustic streaming flow

    Energy Technology Data Exchange (ETDEWEB)

    Sou, In Mei; Ray, Chittaranjan [University of Hawaii at Manoa, Department of Civil and Environmental Engineering, Honolulu, HI (United States); Allen, John S.; Layman, Christopher N. [University of Hawaii at Manoa, Department of Mechanical Engineering, Honolulu, HI (United States)

    2011-11-15

    Subsurface coherent structures and surface temperatures are investigated using simultaneous measurements of particle image velocimetry (PIV) and infrared (IR) thermography. Results for coherent structures from acoustic streaming and associated heating transfer in a rectangular tank with an acoustic horn mounted horizontally at the sidewall are presented. An observed vortex pair develops and propagates in the direction along the centerline of the horn. From the PIV velocity field data, distinct kinematic regions are found with the Lagrangian coherent structure (LCS) method. The implications of this analysis with respect to heat transfer and related sonochemical applications are discussed. (orig.)

  12. Finding the location of the instantaneous center of rotation using a particle image velocimetry algorithm

    Science.gov (United States)

    Claessens, Tom

    2017-03-01

    This work is about planar rigid-body kinematics and, in particular, the principle of the instantaneous center of rotation (IC). Using a computer simulated approach, a workflow is presented that results in a visual representation of the locus of the IC, based on particle image velocimetry (PIV). Here, a small number of digital animations of textured objects are created with multibody dynamics software, and later imported in PIV software to extract the velocity field (magnitude and direction) of objects moving within a plane. We believe the workflow presented may help learners improve their understanding of the concept of the IC, thus enhancing their knowledge of rigid body kinematics.

  13. Experimental observation using particle image velocimetry of inertial waves in a rotating fluid

    Energy Technology Data Exchange (ETDEWEB)

    Messio, Laura; Morize, Cyprien; Rabaud, Marc; Moisy, Frederic [Univ Paris-Sud; Univ Pierre et Marie Curie, CNRS, Orsay (France); Fluides, Automatique et Systemes Thermiques (FAST), Orsay (France)

    2008-04-15

    Inertial waves generated by a small oscillating disk in a rotating water filled cylinder are observed by means of a corotating particle image velocimetry system. The wave takes place in a stationary conical wavepacket, whose angle aperture depends on the oscillation frequency. Direct visualisation of the velocity and vorticity fields in a plane normal to the rotation axis are presented. The characteristic wavelength is found to be approximately equal to the disk diameter. The classical dispersion relation for plane waves is verified from the radial location of the wavepacket, and from the ellipticity of the projected velocity diagram. (orig.)

  14. Speckle and fringe dynamics in imagingspeckle-pattern interferometry for spatial-filtering velocimetry

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Iversen, Theis F. Q.; Yura, Harold T.

    2011-01-01

    This paper analyzes the dynamics of laser speckles and fringes, formed in an imaging-speckle-pattern interferometer with the purpose of sensing linear three-dimensional motion and out-of-plane components of rotation in real time, using optical spatial-filtering-velocimetry techniques. The ensemble...... and direction of all three linear displacement components of the object movement can be determined. Simultaneously, out-ofplane rotation of the object including the corresponding directions can be determined from the spatial gradient of the in-plane fringe motion throughout the observation plane. The theory...

  15. PIVlab – Towards User-friendly, Affordable and Accurate Digital Particle Image Velocimetry in MATLAB

    Directory of Open Access Journals (Sweden)

    William Thielicke

    2014-10-01

    Full Text Available Digital particle image velocimetry (DPIV is a non-intrusive analysis technique that is very popular for mapping flows quantitatively. To get accurate results, in particular in complex flow fields, a number of challenges have to be faced and solved: The quality of the flow measurements is affected by computational details such as image pre-conditioning, sub-pixel peak estimators, data validation procedures, interpolation algorithms and smoothing methods. The accuracy of several algorithms was determined and the best performing methods were implemented in a user-friendly open-source tool for performing DPIV flow analysis in Matlab.

  16. Measurement of Cytoplasmic Streaming in Chara Corallina by Magnetic Resonance Velocimetry

    CERN Document Server

    van de Meent, Jan-Willem; Gladden, Lynn F; Goldstein, Raymond E

    2009-01-01

    In aquatic plants such as the Characean algae, the force generation that drives cyclosis is localized within the cytoplasm, yet produces fluid flows throughout the vacuole. For this to occur the tonoplast must transmit hydrodynamic shear efficiently. Here, using magnetic resonance velocimetry, we present the first whole-cell measurements of the cross-sectional longitudinal velocity field in Chara corallina and show that it is in quantitative agreement with a recent theoretical analysis of rotational cytoplasmic streaming driven by bidirectional helical forcing in the cytoplasm, with direct shear transmission by the tonoplast.

  17. A survey of particle image velocimetry applications in Langley aerospace facilities

    Science.gov (United States)

    Humphreys, W. M.; Bartram, S. M.; Blackshire, J. L.

    1993-01-01

    This paper describes several applications of the global velocity measurement technique known as particle image velocimetry to three different facilities at Langley Research Center. These three applications represent global velocity measurements in distinctly different flows, namely a reacting hydrogen - air flame, a low Reynolds number boundary layer, and hypersonic flow over a wedge. In addition, these applications illustrate the power of the instrument to obtain data such as vorticity and Reynolds stress. Finally, the ability to obtain particle dynamics data in supersonic/hypersonic flows similar to that which can be obtained with point measurement techniques is demonstrated.

  18. Parallel processing system for rapid analysis of speckle-photography and particle-image-velocimetry data.

    Science.gov (United States)

    Huntley, J M; Goldrein, H T; Benckert, L R

    1993-06-10

    An automated system has been constructed to process double-exposure speckle-photography and particle-image-velocimetry images. A 3 × 3 array of laser beams probes the photograph, forming nine fringe patterns in parallel; these are then analyzed sequentially by digital computer and the use of a two-dimensional Fourier-transform method. Results are presented showing that the random errors in the measured displacements from such a system approach the expected speckle-noise-limited performance, with a total analysis time per displacement vector of 160 ms.

  19. Observing Electrokinetic Janus Particle-Channel Wall Interaction Using Microparticle Image Velocimetry.

    Science.gov (United States)

    Boymelgreen, Alicia; Yossifon, Gilad

    2015-08-01

    Three-dimensional/two-component microparticle image velocimetry is used to examine the hydrodynamic flow patterns around metallodielectric Janus particles 15 μm in diameter adjacent to insulating and conducting walls. Far from the walls, the observed flow patterns are in good qualitative agreement with previous experimental and analytical models. However, close to the conducting wall, strong electrohydrodynamic flows are observed at low frequencies, which result in fluid being injected toward the particle. The proximity of the metallic hemisphere to the conducting wall is also shown to produce a localized field gradient, which results in dielectrophoretic trapping of 300 nm polystyrene particles across a broad range of frequencies.

  20. Multiple-plane particle image velocimetry using a light-field camera.

    Science.gov (United States)

    Skupsch, Christoph; Brücker, Christoph

    2013-01-28

    Planar velocity fields in flows are determined simultaneously on parallel measurement planes by means of an in-house manufactured light-field camera. The planes are defined by illuminating light sheets with constant spacing. Particle positions are reconstructed from a single 2D recording taken by a CMOS-camera equipped with a high-quality doublet lens array. The fast refocusing algorithm is based on synthetic-aperture particle image velocimetry (SAPIV). The reconstruction quality is tested via ray-tracing of synthetically generated particle fields. The introduced single-camera SAPIV is applied to a convective flow within a measurement volume of 30 x 30 x 50 mm³.

  1. New Laser Doppler Velocimetry with Wide Dynamic Range and Clear Directional Discrimination

    Institute of Scientific and Technical Information of China (English)

    GUI Hua-Qiao; L(U) Liang; HE De-Yong; XU Jun; XIE Jian-Ping; ZHAO Tian-Peng; WANG An-Ting; MING Hai

    2005-01-01

    @@ We present a new laser Doppler velocimetry based on self-mixing effect using a single longitudinal-mode verticalcavity surface-emitting laser modulated by a dynamic triangular current. It can indicate the direction of velocity without ambiguity in a wide dynamic range of 5.2-479.9mm/s. The accuracy of velocity measurement is better than 3.1% in the whole velocity range when a diffusing target is used for measurements. More interestingly, it works very well on different diffusing surfaces, even on a black glossy photographic paper.

  2. Estimation of turbulent energy dissipation in the boundary layer using Smoke Image Velocimetry

    Science.gov (United States)

    Mikheev, N. I.; Goltsman, A. E.; Saushin, I. I.; Dushina, O. A.

    2017-08-01

    Turbulent energy dissipation in the turbulent boundary layer has been estimated experimentally. Dissipation has been derived from dynamics of two-component instantaneous velocity vector fields measured by an optical method. Smoke Image Velocimetry technique based on digital processing of smoke visualization of flow and adapted to relatively large smoke displacement between two consecutive video frames has been employed. The obtained dissipation profiles have been compared with measurements by multi-sensor hot-wire anemometers, stereo PIV, Tomo-3D-PTV with VIC+, and DNS results.

  3. Incorporating user motivations to design for video tagging

    NARCIS (Netherlands)

    Velsen, van Lex; Melenhorst, Mark

    2009-01-01

    User video tagging can enhance the indexing of large collections of videos, or can provide the basis for personalizing output. However, before the benefits of tagging can be reaped, users must be motivated to provide videos with tags. This article describes a two-stage study that aimed at collecting

  4. Steering gameplay behavior in the interactive tag playground

    NARCIS (Netherlands)

    Delden, van Robby; Moreno, Alejandro; Poppe, Ronald; Reidsma, Dennis; Heylen, Dirk; Aarts, Emile; Ruyter, de Boris; Markopoulos, Panos; Loenen, van Evert; Wichert, Reiner; Schouten, Ben; Terken, Jacques; Kranenburg, van Rob; Ouden, den Elke; O'Hare, Gregory

    2014-01-01

    This paper deals with steering player behavior in the Interactive Tag Playground (ITP). The ITP, an ambient environment instrumented with contact-free sensor technology and ambient display capabilities, enhances the traditional game of tag by determining when a valid tag has been made and visualisin

  5. Steering Gameplay Behavior in the Interactive Tag Playground

    NARCIS (Netherlands)

    Van Delden, Robby; Moreno, Alejandro; Poppe, Ronald; Reidsma, Dennis; Heylen, Dirk K J

    2014-01-01

    This paper deals with steering player behavior in the Interactive Tag Playground (ITP). The ITP, an ambient environment instrumented with contact-free sensor technology and ambient display capabilities, enhances the traditional game of tag by determining when a valid tag has been made and visualisin

  6. Tags in Domain-Specific Sites - New Information?

    DEFF Research Database (Denmark)

    Steinhauer, Jeremy; Delcambre, Lois M.L.; Maier, David;

    2011-01-01

    If researchers use tags in retrieval applications they might assume, implicitly, that tags represent novel information, e.g., when they attribute performance improvement in their retrieval algorithm(s) to the use of tags. In this work, we investigate whether this assumption is true. We focus...

  7. Exploiting phase measurements of EPC Gen2 RFID tags

    NARCIS (Netherlands)

    Huiting, J.; Flisijn, Hubert; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2013-01-01

    This paper presents a 2d localization system for UHF RFID tags. By measuring the phase between the transmitted continuous wave and received backscatter from the tag at different frequencies, it is possible to estimate the distance between the reader and tag. By determining distance estimates to thre

  8. Bus and Tag Terminators for IBM system/360

    CERN Multimedia

    Control units were connected to the channels with "Bus and Tag" cable pairs. The bus cables carried the address and data information and the tag cables identified what data was on the bus. There were three general types of bus-and-tag cables produced by IBM.

  9. Extending a Hybrid Tag-Based Recommender System with Personalization

    DEFF Research Database (Denmark)

    Durao, Frederico; Dolog, Peter

    2010-01-01

    extension for a hybrid tag-based recommender system, which suggests similar Web pages based on the similarity of their tags. The semantic extension aims at discovering tag relations which are not considered in basic syntax similarity. With the goal of generating more semantically grounded recommendations...

  10. Several Affinity Tags Commonly Used in Chromatographic Purification

    Directory of Open Access Journals (Sweden)

    Xinyu Zhao

    2013-01-01

    Full Text Available Affinity tags have become powerful tools from basic biological research to structural and functional proteomics. They were widely used to facilitate the purification and detection of proteins of interest, as well as the separation of protein complexes. Here, we mainly discuss the benefits and drawbacks of several affinity or epitope tags frequently used, including hexahistidine tag, FLAG tag, Strep II tag, streptavidin-binding peptide (SBP tag, calmodulin-binding peptide (CBP, glutathione S-transferase (GST, maltose-binding protein (MBP, S-tag, HA tag, and c-Myc tag. In some cases, a large-size affinity tag, such as GST or MBP, can significantly impact on the structure and biological activity of the fusion partner protein. So it is usually necessary to excise the tag by protease. The most commonly used endopeptidases are enterokinase, factor Xa, thrombin, tobacco etch virus, and human rhinovirus 3C protease. The proteolysis features of these proteases are described in order to provide a general guidance on the proteolytic removal of the affinity tags.

  11. Exploiting phase measurements of EPC Gen2 RFID tags

    NARCIS (Netherlands)

    Huiting, J.; Flisijn, Hubert; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2013-01-01

    This paper presents a 2d localization system for UHF RFID tags. By measuring the phase between the transmitted continuous wave and received backscatter from the tag at different frequencies, it is possible to estimate the distance between the reader and tag. By determining distance estimates to

  12. 29 CFR 1926.417 - Lockout and tagging of circuits.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Lockout and tagging of circuits. 1926.417 Section 1926.417... Practices § 1926.417 Lockout and tagging of circuits. (a) Controls. Controls that are to be deactivated during the course of work on energized or deenergized equipment or circuits shall be tagged....

  13. The Effects of Target Audience on Social Tagging

    Science.gov (United States)

    Alsarhan, Hesham

    2013-01-01

    Online social bookmarking systems allow users to assign tags (i.e., keywords) to represent the content of resources. Research on the effects of target audience on social tagging suggests that taggers select different tags for themselves, their community (e.g., family, friends, colleagues), and the general public (Panke & Gaiser, 2009; Pu &…

  14. Mapping Scrambled Korean Sentences into English Using Synchronous TAGs

    CERN Document Server

    Park, H S

    1995-01-01

    Synchronous Tree Adjoining Grammars can be used for Machine Translation. However, translating a free order language such as Korean to English is complicated. I present a mechanism to translate scrambled Korean sentences into English by combining the concepts of Multi-Component TAGs (MC-TAGs) and Synchronous TAGs (STAGs).

  15. Utilizing HapMap and tagging SNPs.

    Science.gov (United States)

    Haiman, Christopher A; Stram, Daniel O

    2008-01-01

    Advancements in our understanding of variation in the human genome and rapid improvements in high-throughput genotyping technology have made it feasible to study most of the human genetic diversity that is due to common variations in relation to observable phenotypes. Over the past few years, public SNP databases have matured and empirical genome-wide SNP data, such as that generated by the International HapMap Project, have shown the utility and efficiency of selecting and testing informative markers ("tag SNPs") that exploit redundancies among nearby polymorphisms due to linkage disequilibrium (LD). In this chapter, we will demonstrate how to use the HapMap resource and the Haploview program to process and analyze genetic data from HapMap, to evaluate LD relations between SNPs, and to select tagging SNPs to be examined in disease association studies.

  16. Systematics of quark/gluon tagging

    Science.gov (United States)

    Gras, Philippe; Höche, Stefan; Kar, Deepak; Larkoski, Andrew; Lönnblad, Leif; Plätzer, Simon; Siódmok, Andrzej; Skands, Peter; Soyez, Gregory; Thaler, Jesse

    2017-07-01

    By measuring the substructure of a jet, one can assign it a "quark" or "gluon" tag. In the eikonal (double-logarithmic) limit, quark/gluon discrimination is determined solely by the color factor of the initiating parton ( C F versus C A ). In this paper, we confront the challenges faced when going beyond this leading-order understanding, using both parton-shower generators and first-principles calculations to assess the impact of higher-order perturbative and nonperturbative physics. Working in the idealized context of electron-positron collisions, where one can define a proxy for quark and gluon jets based on the Lorentz structure of the production vertex, we find a fascinating interplay between perturbative shower effects and nonperturbative hadronization effects. Turning to proton-proton collisions, we highlight a core set of measurements that would constrain current uncertainties in quark/gluon tagging and improve the overall modeling of jets at the Large Hadron Collider.

  17. Emotional Mining: Tagging Emoticons to Online News

    Science.gov (United States)

    Kasinathan, Vinothini; Mustapha, Aida; Zhi Yong, Lee; Aida Zamnah, Z. A.

    2017-08-01

    This paper presents an emotion mining system, which assigns emoticons to newspaper articles into a pre-defined emotion category based on the underlying emotion in the news. Next, the system makes recommendation to the reader by tagging the news headline with the respective emoticons. Users are then able to decide whether to read the news based on the emoticons provided. The system also provides a filter for the users to choose the category of news to read following the emoticons.

  18. Light stop squarks and b-tagging

    CERN Document Server

    Ferretti, Gabriele; Petersson, Christoffer; Torre, Riccardo

    2015-01-01

    A significant part of the parameter space for light stop squarks still remains unconstrained by collider searches. For both R-Parity Conserving (RPC) and R-Parity Violating (RPV) scenarios there are regions in which the stop mass is around or below the top quark mass that are particularly challenging experimentally. Here we review the status of light stop searches, both in RPC and RPV scenarios. We also propose strategies, generally based on exploiting b-tagging, to cover the unconstrained regions.

  19. Clinical application of tagging snapshot MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kumada, Masanobu; Niimi, Seiji (Tokyo Univ. (Japan). Faculty of Medicine); Niitsu, Mamoru

    1994-04-01

    The present study was to determine the contraction of the tongue-related muscles during the production of 5 Japanese vowels by tagging snapshot MRI. The tagging snapshot pulse sequence had three components: a contrast preparation pulse, subsequent tagging pulses and a data acquisition phase. When a vowel was uttered, the stripes were displaced, indicating the displacement of the tissues. The subjects were a 35-year-old and a 30-year-old Japanese men. Images of 5 vowels and the reference position were acquired. Six lines were imposed with their anatomical meanings on MRI, representing fibers of the anterior, middle and posterior parts of the genioglossus muscles (GGa, GGm, GGp), superior-longitudinalis muscle (SL), inferior-longitudinalis muscle (IL) and verticalis muscle (V). The lengths of these lines were measured for the contractions of the muscles along these lines. During the utterance of /a/, the contraction of GGa, V and SL seemed to cause the shortening of the tongue in the vertical axis. During the utterance of /i/, GGm and GGp seemed to contract to pull the tongue toward the chin to make the tongue shorter in the longitudinal axis. During the utterance of /u/, the contraction of GGa, GGp and IL made the tongue shorter in the vertical and longitudinal axes. During the utterance of /e/, GGp contracted as of /i/, although the tongue position was lower for /e/ than /i/. During the utterance of /o/, GGp contracted to pull the bottom of the tongue against the contraction of SG to pull back the upper part of the tongue. A newly developed tagging snapshot MRI is capable of imaging the 'inner' construction of the tongue and the contraction of the muscles during speech production. (N.K.).

  20. TAG Oil hunting elephants in New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Anon

    2005-10-15

    Calgary-based TAG Oil is an exploration company that manages 4.1 million acres of major producing oil and gas fields in New Zealand. The enormous Maui field, with 4 tcf of natural gas in place, has dominated the gas market in New Zealand by meeting nearly 90 per cent of the country's energy demand at costs much lower than world prices. However, the maturing field is in decline and will cease production by 2008. New gas field discoveries will only meet 60 per cent of the country's energy requirements for 5 additional years. Unless new large reserves of gas are discovered, the supply and demand situation will get worse. Lead time to place new production on-stream requires 5 to 10 years, which creates a large supply gap over the next decade. Public resistance to coal-fired power plants, new hydroelectric dams and nuclear power has left the country with no viable alternative to natural gas. TAG Oil has taken this unique opportunity to create value when gas demand is at its maximum and energy alternatives are at a minimum. This paper presented 8 reasons why New Zealand is a good place for petroleum investment. Most exploration has occurred in the Taranaki Basin, where only 130 exploration wells have been drilled. The rest of the sedimentary basins are essentially unexplored, although many exhibit oil seeps and have hydrocarbon potential. In 1998, an onshore gas discovery was made on the East Coast Basin. Sub-commercial discoveries have also been made in the offshore Canterbury and Great South basins. TAG Oil is focusing on shallow oil and gas pools in the Miocene reservoirs at Taranaki, as well as on deeper gas prospects in Tariki and Kapuni Sands. One of the challenges was a shortage of drilling rigs, so TAG is having a rig built in Calgary and shipped south. 2 figs.

  1. TAG Oil hunting elephants in New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2005-10-01

    Calgary-based TAG Oil is an exploration company that manages 4.1 million acres of major producing oil and gas fields in New Zealand. The enormous Maui field, with 4 tcf of natural gas in place, has dominated the gas market in New Zealand by meeting nearly 90 per cent of the country's energy demand at costs much lower than world prices. However, the maturing field is in decline and will cease production by 2008. New gas field discoveries will only meet 60 per cent of the country's energy requirements for 5 additional years. Unless new large reserves of gas are discovered, the supply and demand situation will get worse. Lead time to place new production on-stream requires 5 to 10 years, which creates a large supply gap over the next decade. Public resistance to coal-fired power plants, new hydroelectric dams and nuclear power has left the country with no viable alternative to natural gas. TAG Oil has taken this unique opportunity to create value when gas demand is at its maximum and energy alternatives are at a minimum. This paper presented 8 reasons why New Zealand is a good place for petroleum investment. Most exploration has occurred in the Taranaki Basin, where only 130 exploration wells have been drilled. The rest of the sedimentary basins are essentially unexplored, although many exhibit oil seeps and have hydrocarbon potential. In 1998, an onshore gas discovery was made on the East Coast Basin. Sub-commercial discoveries have also been made in the offshore Canterbury and Great South basins. TAG Oil is focusing on shallow oil and gas pools in the Miocene reservoirs at Taranaki, as well as on deeper gas prospects in Tariki and Kapuni Sands. One of the challenges was a shortage of drilling rigs, so TAG is having a rig built in Calgary and shipped south. 2 figs.

  2. Characterizing Chilean blue whale vocalizations with DTAGs: a test of using tag accelerometers for caller identification.

    Science.gov (United States)

    Saddler, Mark R; Bocconcelli, Alessandro; Hickmott, Leigh S; Chiang, Gustavo; Landea-Briones, Rafaela; Bahamonde, Paulina A; Howes, Gloria; Segre, Paolo S; Sayigh, Laela S

    2017-09-07

    Vocal behavior of blue whales (Balaenoptera musculus) in the Gulf of Corcovado, Chile, was analyzed using both audio and accelerometer data from digital acoustic recording tags (DTAGs). Over the course of three austral summers (2014, 2015, 2016), seventeen tags were deployed, yielding 124 hours of data. We report the occurrence of Southeast Pacific type 2 (SEP2) calls, which exhibit peak frequencies, durations, and timing consistent with previous recordings made using towed and moored hydrophones. We also describe tonal downswept (D) calls, which have not been previously described for this population. Since being able to accurately assign vocalizations to individual whales is fundamental for studying communication and for estimating population densities from call rates, we further examine the feasibility of using high-resolution DTAG accelerometers to identify low-frequency calls produced by tagged blue whales. We cross-correlated acoustic signals with simultaneous tri-axial accelerometer readings in order to analyze the phase match as well as the amplitude of accelerometer signals associated with low-frequency calls, which provides a quantitative method of determining if a call is associated with a detectable acceleration signal. Our results suggest that vocalizations from nearby individuals are also capable of registering accelerometer signals in the tagged whale's DTAG record. We cross-correlate acceleration vectors between calls to explore the possibility of using signature acceleration patterns associated with sounds produced within the tagged whale as a new method of identifying which accelerometer-detectable calls originate from the tagged animal. © 2017. Published by The Company of Biologists Ltd.

  3. Global navigation system with RFID tags

    Science.gov (United States)

    Tsukiyama, Toshifumi

    2002-02-01

    A new navigation system is described for a mobile robot moving around in man-made environments such as hallways in a building. The system is based on a commercial three-wheel mobile platform with the addition of a Linux-based laptop computer, a Radio Frequency Identification (RDID) tag sensor and a vision system. At critical junctions such as the intersection of two passages the navigation system must identify the robot's location on a given map. We propose a method using RFID tags as landmarks. Each RFID tag has a unique ID number corresponding to its location on the map. The navigation system can decide the next movement (left-turn, right-turn and so on) toward a given goal based on this number. The navigation system also can automatically follow walls using the vision system. Since the equipment setup is very simple and the navigation system is easily combined with general mobile robot systems, our proposed technique would be useful for real-world robotic applications such as intelligent navigation for motorized wheelchairs.

  4. An approach to sequence DNA without tagging

    Science.gov (United States)

    Niu, Sanjun; Saraf, Ravi F.

    2002-10-01

    Microarray technology is playing an increasingly important role in biology and medicine and its application to genomics for gene expression analysis has already reached the market with a variety of commercially available instruments. In these combinatorial analysis methods, known probe single-strand DNA (ssDNA) 'primers' are attached in clusters of typically 100 µm × 100 µm pixels. Each pixel of the array has a slightly different sequence. On exposure to 'unknown' target ssDNA, the pixels with the right complementary probe ssDNA sequence convert to double-stranded DNA (dsDNA) by a hybridization reaction. To transduct the conversion of the pixel to dsDNA, the target ssDNA is labelled with a photoluminescent tag during the polymerase chain reaction (PCR) amplification process. Due to the statistical distribution of the tags in the target ssDNA, it becomes significantly difficult to implement these methods as a diagnostic tool in a pathology laboratory. A method to sequence DNA without tagging the molecule is developed. The fabrication process is compatible with current microelectronics and (emerging) soft-material fabrication technologies, allowing the method to be integrable with micro-electromechanical systems (MEMS) and lab-on-a-chip devices. An estimated sensitivity of 10-12 g on a 1 cm2 device area is obtained.

  5. A Personalized Tag-Based Recommendation in Social Web Systems

    DEFF Research Database (Denmark)

    Durao, Frederico; Dolog, Peter

    2009-01-01

    -based recommender system which suggests similar Web pages based on the similarity of their tags from a Web 2.0 tagging application. The proposed approach extends the basic similarity calculus with external factors such as tag popularity, tag representativeness and the affinity between user and tag. In order...... to study and evaluate the recommender system, we have conducted an experiment involving 38 people from 12 countries using data from Del.icio.us , a social bookmarking web system on which users can share their personal bookmarks...

  6. APPECT: An Approximate Backbone-Based Clustering Algorithm for Tags

    DEFF Research Database (Denmark)

    Zong, Yu; Xu, Guandong; Jin, Pin

    2011-01-01

    algorithm for Tags (APPECT). The main steps of APPECT are: (1) we execute the K-means algorithm on a tag similarity matrix for M times and collect a set of tag clustering results Z={C1,C2,…,Cm}; (2) we form the approximate backbone of Z by executing a greedy search; (3) we fix the approximate backbone...... resulting from the severe difficulty of ambiguity, redundancy and less semantic nature of tags. Clustering method is a useful tool to address the aforementioned difficulties. Most of the researches on tag clustering are directly using traditional clustering algorithms such as K-means or Hierarchical...

  7. APPECT: An Approximate Backbone-Based Clustering Algorithm for Tags

    DEFF Research Database (Denmark)

    Zong, Yu; Xu, Guandong; Jin, Pin

    2011-01-01

    algorithm for Tags (APPECT). The main steps of APPECT are: (1) we execute the K-means algorithm on a tag similarity matrix for M times and collect a set of tag clustering results Z={C1,C2,…,Cm}; (2) we form the approximate backbone of Z by executing a greedy search; (3) we fix the approximate backbone...... resulting from the severe difficulty of ambiguity, redundancy and less semantic nature of tags. Clustering method is a useful tool to address the aforementioned difficulties. Most of the researches on tag clustering are directly using traditional clustering algorithms such as K-means or Hierarchical...

  8. Velocimetry modalities for secondary flows in a curved artery test section

    Science.gov (United States)

    Bulusu, Kartik V.; Elkins, Christopher J.; Banko, Andrew J.; Plesniak, Michael W.; Eaton, John K.

    2014-11-01

    Secondary flow structures arise due to curvature-related centrifugal forces and pressure imbalances. These flow structures influence wall shear stress and alter blood particle residence times. Magnetic resonance velocimetry (MRV) and particle image velocimetry (PIV) techniques were implemented independently, under the same physiological inflow conditions (Womersley number = 4.2). A 180-degree curved artery test section with curvature ratio (1/7) was used as an idealized geometry for curved arteries. Newtonian blood analog fluids were used for both MRV and PIV experiments. The MRV-technique offers the advantage of three-dimensional velocity field acquisition without requiring optical access or flow markers. Phase-averaged, two-dimensional, PIV-data at certain cross-sectional planes and inflow phases were compared to phase-averaged MRV-data to facilitate the characterization of large-scale, Dean-type vortices. Coherent structures detection methods that included a novel wavelet decomposition-based approach to characterize these flow structures was applied to both PIV- and MRV-data. The overarching goal of this study is the detection of motific, three-dimensional shapes of secondary flow structures using MRV techniques with guidance obtained from high fidelity, 2D-PIV measurements. This material is based in part upon work supported by the National Science Foundation under Grant Number CBET-0828903, and GW Center for Biomimetics and Bioinspired Engineering (COBRE).

  9. Effects of humic acid on physical and hydrodynamic properties of kaolin flocs by particle image velocimetry.

    Science.gov (United States)

    Zhong, Runsheng; Zhang, Xihui; Xiao, Feng; Li, Xiaoyan; Cai, Zhonghua

    2011-07-01

    The physical and hydrodynamic properties of kaolin flocs including floc size, strength, regrowth, fractal structure and settling velocity were investigated by in situ particle image velocimetry technique at different humic acid concentration. Jar-test experimental results showed that the adsorbed humic acid had a significant influence on the coagulation process for alum and ferric chloride. Kaolin flocs formed with the ferric chloride were larger and stronger than those for alum at same humic acid concentration. Floc strength and regrowth were estimated by strength factor and recovery factor at different humic acid concentration. It was found that the increased humic acid concentration had a slight influence on the strength of kaolin flocs and resulted in much worse floc regrowth. In addition, the floc regrowth after breakage depended on the shear history and coagulants under investigation. The changes in fractal structure recorded continuously by in situ particle image velocimetry technique during the growth-breakage-regrowth processes provided a supporting information that the kaolin flocs exhibited a multilevel structure. It was proved that the increased humic acid concentration resulted in decrease in mass fractal dimension of kaolin flocs and consequently worse sedimentation performance through free-settling and microbalance techniques. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Cell Image Velocimetry (CIV): boosting the automated quantification of cell migration in wound healing assays.

    Science.gov (United States)

    Milde, Florian; Franco, Davide; Ferrari, Aldo; Kurtcuoglu, Vartan; Poulikakos, Dimos; Koumoutsakos, Petros

    2012-11-01

    Cell migration is commonly quantified by tracking the speed of the cell layer interface in wound healing assays. This quantification is often hampered by low signal to noise ratio, in particular when complex substrates are employed to emulate in vivo cell migration in geometrically complex environments. Moreover, information about the cell motion, readily available inside the migrating cell layers, is not usually harvested. We introduce Cell Image Velocimetry (CIV), a combination of cell layer segmentation and image velocimetry algorithms, to drastically enhance the quantification of cell migration by wound healing assays. The resulting software analyses the speed of the interface as well as the detailed velocity field inside the cell layers in an automated fashion. CIV is shown to be highly robust for images with low signal to noise ratio, low contrast and frame shifting and it is portable across various experimental settings. The modular design and parametrization of CIV is not restricted to wound healing assays and allows for the exploration and quantification of flow phenomena in any optical microscopy dataset. Here, we demonstrate the capabilities of CIV in wound healing assays over topographically engineered surfaces and quantify the relative merits of differently aligned gratings on cell migration.

  11. Validation of Multi-plane Particle Shadow Velocimetry to Quantify Turbulence Scales

    Science.gov (United States)

    Truong, Christine; Hinkle, Steven; Sinding, Kyle; Harris, Jeff; Krane, Michael; Jefferies, Rhett

    2016-11-01

    Estimates of radial integral length scales using multi-plane Particle Shadow Velocimetry (PSV) are presented using measurements from the 11.2-inch diameter glycerin tunnel in the Applied Research Lab Garfield Thomas Water Tunnel. Particle shadow velocimetry (PSV) enables illumination of a volume and is an efficient means of obtaining multi-plane illumination. The combination of two colors in the LED backlight and a dichroic mirror makes possible the imaging of two planes in space. Thus, velocity fields in two imaging planes separated radially along the optical axis can be simultaneously measured. These multi-plane velocity fields are correlated over a range of separations to obtain integral length scales. Integral time scales are also calculated and converted into a streamwise length scale using Taylor's hypothesis for further confirmation. The inter-plane radial length scales, the in-plane length scales, the converted time scale in the inter-plane radial direction, and multi-plane turbulent statistics are compared with published studies, which used proven measurement methods. An additional, independent check is provided from PSV measurements in a single radial-axial plane.

  12. Liquid nitrogen in fluid dynamics: Visualization and velocimetry using frozen particles

    Science.gov (United States)

    Fonda, Enrico; Sreenivasan, Katepalli R.; Lathrop, Daniel P.

    2012-08-01

    High-Reynolds-number flows are common both in nature and industrial applications, but are difficult to attain in laboratory settings using standard test fluids such as air and water. To extend the Reynolds number range, water and air have been replaced at times by low-viscosity fluids such as pressurized air, sulfur hexafluoride, and cryogenic nitrogen gas, as well as liquid and gaseous helium. With a few exceptions, liquid nitrogen has been neglected despite the fact that it has a kinematic viscosity of about a fifth of that of water at room temperature. We explore the use of liquid nitrogen here. In particular, we study the use of frozen particles for flow visualization and velocimetry in liquid nitrogen. We create particles in situ by injecting a gaseous mixture of room-temperature nitrogen and an additional seeding gas into the flow. We present a systematic study of potential seeding gases to determine which create particles with the best fidelity and optical properties. The technique has proven capable of producing sub-micrometer sized tracers that allow particle tracking and particle image velocimetry. We review possible high-Reynolds-number experiments using this technique, and discuss the merits and challenges of using liquid nitrogen as a test fluid.

  13. Three-dimensional particle tracking velocimetry applied to granular flows down rotating chutes

    Science.gov (United States)

    Clercx, Herman; Shirsath, Sushil; Padding, Johan; Kuipers, Hans

    2014-11-01

    We report on the cross-validation of 3D particle tracking velocimetry (3D-PTV) with other measurement techniques, such as particle image velocimetry (PIV), electronic ultrasonic sensor measurements for bed height and the discrete element model (DEM), for gaining more insight into the behavior of granular flows down inclined rotating chutes. In particular we aim at gaining access to Lagrangian displacement data of surface particles in granular flows and to obtain independent measurements of both the surface velocity and the bed height in the chute. The 3D-PTV method is based on imaging and tracking colored tracer particles that are introduced in the granular material, which are viewed from three directions. The three cameras collect consecutive frames a known Δt apart and the PTV algorithm for locating and tracking particles is used to determine particle trajectories and velocities. The PTV and PIV results are in good mutual agreement with regard to the streamwise and spanwise surface velocity. The particle bed height obtained from 3D-PTV was compared with data from an ultrasonic bed-height sensor and it is found to be in good mutual agreement, as was the case for the comparison between the experimental findings from 3D-PTV and simulations by DEM.

  14. Reconstruction of an acoustic pressure field in a resonance tube by particle image velocimetry.

    Science.gov (United States)

    Kuzuu, K; Hasegawa, S

    2015-11-01

    A technique for estimating an acoustic field in a resonance tube is suggested. The estimation of an acoustic field in a resonance tube is important for the development of the thermoacoustic engine, and can be conducted employing two sensors to measure pressure. While this measurement technique is known as the two-sensor method, care needs to be taken with the location of pressure sensors when conducting pressure measurements. In the present study, particle image velocimetry (PIV) is employed instead of a pressure measurement by a sensor, and two-dimensional velocity vector images are extracted as sequential data from only a one- time recording made by a video camera of PIV. The spatial velocity amplitude is obtained from those images, and a pressure distribution is calculated from velocity amplitudes at two points by extending the equations derived for the two-sensor method. By means of this method, problems relating to the locations and calibrations of multiple pressure sensors are avoided. Furthermore, to verify the accuracy of the present method, the experiments are conducted employing the conventional two-sensor method and laser Doppler velocimetry (LDV). Then, results by the proposed method are compared with those obtained with the two-sensor method and LDV.

  15. High Dynamic Velocity Range Particle Image Velocimetry Using Multiple Pulse Separation Imaging

    Directory of Open Access Journals (Sweden)

    Tadhg S. O’Donovan

    2010-12-01

    Full Text Available The dynamic velocity range of particle image velocimetry (PIV is determined by the maximum and minimum resolvable particle displacement. Various techniques have extended the dynamic range, however flows with a wide velocity range (e.g., impinging jets still challenge PIV algorithms. A new technique is presented to increase the dynamic velocity range by over an order of magnitude. The multiple pulse separation (MPS technique (i records series of double-frame exposures with different pulse separations, (ii processes the fields using conventional multi-grid algorithms, and (iii yields a composite velocity field with a locally optimized pulse separation. A robust criterion determines the local optimum pulse separation, accounting for correlation strength and measurement uncertainty. Validation experiments are performed in an impinging jet flow, using laser-Doppler velocimetry as reference measurement. The precision of mean flow and turbulence quantities is significantly improved compared to conventional PIV, due to the increase in dynamic range. In a wide range of applications, MPS PIV is a robust approach to increase the dynamic velocity range without restricting the vector evaluation methods.

  16. Lightweight Distance bound Protocol for Low Cost RFID Tags

    CERN Document Server

    Ahmed, Eslam Gamal; Hashem, Mohamed

    2010-01-01

    Almost all existing RFID authentication schemes (tag/reader) are vulnerable to relay attacks, because of their inability to estimate the distance to the tag. These attacks are very serious since it can be mounted without the notice of neither the reader nor the tag and cannot be prevented by cryptographic protocols that operate at the application layer. Distance bounding protocols represent a promising way to thwart relay attacks, by measuring the round trip time of short authenticated messages. All the existing distance bounding protocols use random number generator and hash functions at the tag side which make them inapplicable at low cost RFID tags. This paper proposes a lightweight distance bound protocol for low cost RFID tags. The proposed protocol based on modified version of Gossamer mutual authentication protocol. The implementation of the proposed protocol meets the limited abilities of low-cost RFID tags.

  17. Individually Identifiable Surface Acoustic Wave Sensors, Tags and Systems

    Science.gov (United States)

    Hines, Jacqueline H. (Inventor); Solie, Leland P. (Inventor); Tucker, Dana Y. G. (Inventor); Hines, Andrew T. (Inventor)

    2017-01-01

    A surface-launched acoustic wave sensor tag system for remotely sensing and/or providing identification information using sets of surface acoustic wave (SAW) sensor tag devices is characterized by acoustic wave device embodiments that include coding and other diversity techniques to produce groups of sensors that interact minimally, reducing or alleviating code collision problems typical of prior art coded SAW sensors and tags, and specific device embodiments of said coded SAW sensor tags and systems. These sensor/tag devices operate in a system which consists of one or more uniquely identifiable sensor/tag devices and a wireless interrogator. The sensor device incorporates an antenna for receiving incident RF energy and re-radiating the tag identification information and the sensor measured parameter(s). Since there is no power source in or connected to the sensor, it is a passive sensor. The device is wirelessly interrogated by the interrogator.

  18. Methodologies for Improved Tag Cloud Generation with Clustering

    DEFF Research Database (Denmark)

    Leginus, Martin; Dolog, Peter; Lage, Ricardo Gomes

    2012-01-01

    coverage and overlap. We study several clustering algorithms to generate tag clouds. We show that by extending cloud generation based on tag popularity with clustering we slightly improve coverage. We also show that if the cloud is generated by clustering independently of the tag popularity baseline we......Tag clouds are useful means for navigation in the social web systems. Usually the systems implement the tag cloud generation based on tag popularity which is not always the best method. In this paper we propose methodologies on how to combine clustering into the tag cloud generation to improve...... better on bibsonomy due to its specific focus. The best performing is the hierarchical clustering....

  19. RAC-tagging: Recombineering And Cas9-assisted targeting for protein tagging and conditional analyses.

    Science.gov (United States)

    Baker, Oliver; Gupta, Ashish; Obst, Mandy; Zhang, Youming; Anastassiadis, Konstantinos; Fu, Jun; Stewart, A Francis

    2016-05-24

    A fluent method for gene targeting to establish protein tagged and ligand inducible conditional loss-of-function alleles is described. We couple new recombineering applications for one-step cloning of gRNA oligonucleotides and rapid generation of short-arm (~1 kb) targeting constructs with the power of Cas9-assisted targeting to establish protein tagged alleles in embryonic stem cells at high efficiency. RAC (Recombineering And Cas9)-tagging with Venus, BirM, APEX2 and the auxin degron is facilitated by a recombineering-ready plasmid series that permits the reuse of gene-specific reagents to insert different tags. Here we focus on protein tagging with the auxin degron because it is a ligand-regulated loss-of-function strategy that is rapid and reversible. Furthermore it includes the additional challenge of biallelic targeting. Despite high frequencies of monoallelic RAC-targeting, we found that simultaneous biallelic targeting benefits from long-arm (>4 kb) targeting constructs. Consequently an updated recombineering pipeline for fluent generation of long arm targeting constructs is also presented.

  20. Comparing semi-analytic particle tagging and hydrodynamical simulations of the Milky Way's stellar halo

    Science.gov (United States)

    Cooper, Andrew P.; Cole, Shaun; Frenk, Carlos S.; Le Bret, Theo; Pontzen, Andrew

    2017-08-01

    Particle tagging is an efficient, but approximate, technique for using cosmological N-body simulations to model the phase-space evolution of the stellar populations predicted, for example, by a semi-analytic model of galaxy formation. We test the technique developed by Cooper et al. (which we call stings here) by comparing particle tags with stars in a smooth particle hydrodynamic (SPH) simulation. We focus on the spherically averaged density profile of stars accreted from satellite galaxies in a Milky Way (MW)-like system. The stellar profile in the SPH simulation can be recovered accurately by tagging dark matter (DM) particles in the same simulation according to a prescription based on the rank order of particle binding energy. Applying the same prescription to an N-body version of this simulation produces a density profile differing from that of the SPH simulation by ≲10 per cent on average between 1 and 200 kpc. This confirms that particle tagging can provide a faithful and robust approximation to a self-consistent hydrodynamical simulation in this regime (in contradiction to previous claims in the literature). We find only one systematic effect, likely due to the collisionless approximation, namely that massive satellites in the SPH simulation are disrupted somewhat earlier than their collisionless counterparts. In most cases, this makes remarkably little difference to the spherically averaged distribution of their stellar debris. We conclude that, for galaxy formation models that do not predict strong baryonic effects on the present-day DM distribution of MW-like galaxies or their satellites, differences in stellar halo predictions associated with the treatment of star formation and feedback are much more important than those associated with the dynamical limitations of collisionless particle tagging.

  1. Performance Analysis of Generic vs.Sliced Tags in HepODBMS

    Institute of Scientific and Technical Information of China (English)

    KurtStockinger

    2001-01-01

    This paper presents a performance analysis of accessing tag data clustered in two different ways,namely event-wise clustering (generic tag)vs.attribute-wise clustering (sliced tag).The results show that especially "Prefetch-optimisation" results in an additional performance gain of sliced tags over generic tags when only a subset of all the tag attributes is accessed.

  2. Comparing semi-analytic particle tagging and hydrodynamical simulations of the Milky Way's stellar halo

    CERN Document Server

    Cooper, Andrew P; Frenk, Carlos S; Bret, Theo Le; Pontzen, Andrew

    2016-01-01

    Particle tagging is an efficient, but approximate, technique for using cosmological N-body simulations to model the phase space evolution of the stellar populations predicted, for example, by a semi-analytic model of galaxy formation. We test the technique developed by Cooper et al. (which we call STINGS here) by comparing particle tags with stars in a smooth particle hydrodynamic (SPH) simulation. We focus on the spherically averaged density profile of stars accreted from satellite galaxies in a Milky Way-like system. The stellar profile in the SPH simulation can be recovered accurately by tagging dark matter particles in the same simulation according to a prescription based on the rank order of particle binding energy. Applying the same prescription to an N-body version of this simulation produces very similar results. This confirms that particle tagging can provide a faithful and robust approximation to a self-consistent hydrodynamical simulation in this regime (in contradiction to previous claims in the l...

  3. Development of techniques for tagging precursor and essential chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Swansiger, W.A.; Shepodd, T.J. [Sandia National Labs., Livermore, CA (United States); Phillips, M.L.F. [Sandia National Labs., Albuquerque, NM (United States)

    1994-01-01

    The ability to identify the manufacturers and distributors of chemicals seized in raids of illicit drug labs would be of great value in controlling the diversion of these chemicals. We developed a tagging scheme based on the addition of sub-ppM concentrations of various combinations of rare-earth elements to the target chemicals and evaluated a number of techniques for detecting the tags. We developed soluble tags for tagging liquids and selected Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) as the preferred detection technique. We developed insoluble tags for tagging solids and developed methods to analyze them and mix them into solid precursors. We have successfully demonstrated the tagging of several solvents and two of the precursor chemicals used in one of the most popular clandestine methamphetamine syntheses (ephedrine reacting with hydriodic acid/red phosphorus). The tagging scheme is capable of yielding tens of thousands of signatures (using holmium as an internal standard and up to 9 rare-earths at up to 3 concentrations yields 3{sup 9} {minus} 1 = 19,682 signatures) and is applicable to most of the chemicals on the precursor and essential chemicals list. In the concentrations employed, the tags are safe enough to be added to pharmaceuticals and cheap enough to tag tanker loads of chemicals.

  4. Learning to rank image tags with limited training examples.

    Science.gov (United States)

    Songhe Feng; Zheyun Feng; Rong Jin

    2015-04-01

    With an increasing number of images that are available in social media, image annotation has emerged as an important research topic due to its application in image matching and retrieval. Most studies cast image annotation into a multilabel classification problem. The main shortcoming of this approach is that it requires a large number of training images with clean and complete annotations in order to learn a reliable model for tag prediction. We address this limitation by developing a novel approach that combines the strength of tag ranking with the power of matrix recovery. Instead of having to make a binary decision for each tag, our approach ranks tags in the descending order of their relevance to the given image, significantly simplifying the problem. In addition, the proposed method aggregates the prediction models for different tags into a matrix, and casts tag ranking into a matrix recovery problem. It introduces the matrix trace norm to explicitly control the model complexity, so that a reliable prediction model can be learned for tag ranking even when the tag space is large and the number of training images is limited. Experiments on multiple well-known image data sets demonstrate the effectiveness of the proposed framework for tag ranking compared with the state-of-the-art approaches for image annotation and tag ranking.

  5. An RF tag communication system model for noise radar

    Science.gov (United States)

    Pan, Qihe; Narayanan, Ram M.

    2008-04-01

    RF (radio-frequency) tags have drawn increasing research interest because of their great potential uses in many radio frequency identification applications. They can also be configured to work with radar as a communication channel by receiving radar acquisition signals, suitably coding these, and retransmitting them back to the radar. This paper proposes a system model for the communication between a noise radar and multiple RF tags. The radar interrogates the RF tags in a region of interest by sending ultrawideband noise signals. Upon receiving the radar's signal, all the tags within the radar's range wake up, and respond to the radar with simple messages. The RF tag filters the radar signal to a unique spectral band, which represents its identification information, and different RF tags occupy different non-overlapping bands of the spectrum of the radar signal. Tag messages are modulated onto the waveform through taps of weighted delays. The radar decodes the RF tag identifications and corresponding messages by cross-correlating the RF tag returned signals with the replica of the radar transmitted signal. Calculations and simulation results both show that the proposed system is capable of communicating simple messages between RF tags and radar.

  6. Investigation of flow behind vortex generators by stereo particle image velocimetry on a thick airfoil near stall

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Hansen, Martin Otto Laver

    2013-01-01

    Stereoscopic Particle Image Velocimetry measurements investigating the effect of vortex generators (VGs) on the flow near stall were carried out in a purpose-built wind tunnel for airfoil investigations on a DU 91-W2-250 profile. Measurements were conducted at Re = 0.9⋅106, corresponding to free...

  7. Acoustic radiation- and streaming-induced microparticle velocities determined by microparticle image velocimetry in an ultrasound symmetry plane

    DEFF Research Database (Denmark)

    Barnkob, Rune; Augustsson, Per; Laurell, Thomas

    2012-01-01

    We present microparticle image velocimetry measurements of suspended microparticles of diameters from 0.6 to 10μm undergoing acoustophoresis in an ultrasound symmetry plane in a microchannel. The motion of the smallest particles is dominated by the Stokes drag from the induced acoustic streaming...

  8. BEHAVIORAL STATES AND DOPPLER VELOCIMETRY OF THE RENAL-ARTERY IN THE NEAR-TERM HUMAN FETUS

    NARCIS (Netherlands)

    LANDER, M; AARNOUDSE, JG; Oosterhof, H.

    Transition of fetal behavioural state IF to 2F coincides with cardiovascular changes measured by Doppler velocimetry e.g. a decrease in pulsatility index (PI) in the internal carotid arteries and in the descending aorta, indicating redistribution of blood flow. Recently, we reported a considerable

  9. Investigation of the unsteadiness of a shock-reflection interaction with time-resolved particle image velocimetry

    NARCIS (Netherlands)

    Van Oudheusden, B.W.; Jöbsis, A.J.P.; Scarano, F.; Souverein, L.J.

    2011-01-01

    The spatio-temporal dynamics of an impinging shock/boundary layer interaction atMach 2 and under incipient separation conditions, has been investigated experimentally by means of high-speed particle image velocimetry (PIV). The available PIV acquisition rate of up to 20 kHz permits a time-resolved c

  10. Analysis of tag-position bias in MPSS technology

    Directory of Open Access Journals (Sweden)

    Rattray Magnus

    2006-04-01

    Full Text Available Abstract Background Massively Parallel Signature Sequencing (MPSS technology was recently developed as a high-throughput technology for measuring the concentration of mRNA transcripts in a sample. It has previously been observed that the position of the signature tag in a transcript (distance from 3' end can affect the measurement, but this effect has not been studied in detail. Results We quantify the effect of tag-position bias in Classic and Signature MPSS technology using published data from Arabidopsis, rice and human. We investigate the relationship between measured concentration and tag-position using nonlinear regression methods. The observed relationship is shown to be broadly consistent across different data sets. We find that there exist different and significant biases in both Classic and Signature MPSS data. For Classic MPSS data, genes with tag-position in the middle-range have highest measured abundance on average while genes with tag-position in the high-range, far from the 3' end, show a significant decrease. For Signature MPSS data, high-range tag-position genes tend to have a flatter relationship between tag-position and measured abundance. Thus, our results confirm that the Signature MPSS method fixes a substantial problem with the Classic MPSS method. For both Classic and Signature MPSS data there is a positive correlation between measured abundance and tag-position for low-range tag-position genes. Compared with the effects of mRNA length and number of exons, tag-position bias seems to be more significant in Arabadopsis. The tag-position bias is reflected both in the measured abundance of genes with a significant tag count and in the proportion of unexpressed genes identified. Conclusion Tag-position bias should be taken into consideration when measuring mRNA transcript abundance using MPSS technology, both in Classic and Signature MPSS methods.

  11. HPV Vaccine Safety PSA (:30) (No Tag)

    Centers for Disease Control (CDC) Podcasts

    2014-01-15

    In this 30 second public service announcement, a mother talks about the importance of protecting 11-12 year-old boys and girls with HPV vaccination. No CDC tag at the end. (Una madre habla sobre la importancia de proteger a los niños y las niñas de 11 a 12 años con la vacuna contra el VPH.).  Created: 1/15/2014 by National Center for Immunizations and Respiratory Diseases (NCIRD).   Date Released: 1/15/2014.

  12. Kaons in flavour tagged B decays

    Science.gov (United States)

    Albrecht, H.; Ehrlichmann, H.; Hamacher, T.; Hofmann, R. P.; Kirchhoff, T.; Nau, A.; Nowak, S.; Schröder, H.; Schulz, H. D.; Walter, M.; Wurth, R.; Hast, C.; Kolanoski, H.; Kosche, A.; Lange, A.; Lindner, A.; Mankel, R.; Schieber, M.; Siegmund, T.; Spaan, B.; Thurn, H.; Töpfer, D.; Wegener, D.; Bittner, M.; Eckstein, P.; Paulini, M. G.; Reim, K.; Wegener, H.; Mundt, R.; Oest, T.; Reiner, R.; Schmidt-Parzefall, W.; Funk, W.; Stiewe, J.; Werner, S.; Ehret, K.; Hofmann, W.; Hüpper, A.; Khan, S.; Knöpfle, K. T.; Seeger, M.; Spengler, J.; Britton, D. I.; Charlesworth, C. E. K.; Edwards, K. W.; Hyatt, E. R. F.; Kapitza, H.; Krieger, P.; Macfarlane, D. B.; Patel, P. M.; Prentice, J. D.; Saull, P. R. B.; Tzamariudaki, K.; van de Water, R. G.; Yoon, T.-S.; Reßing, D.; Schmidtler, M.; Schneider, M.; Schubert, K. R.; Strahl, K.; Waldi, R.; Weseler, S.; Kernel, G.; Križan, P.; Križnič, E.; Podobnik, T.; Živko, T.; Cronström, H. I.; Jönsson, L.; Balagura, V.; Belyaev, I.; Chechelnitsky, S.; Danilov, M.; Droutskoy, A.; Gershtein, Yu.; Golutvin, A.; Kostina, G.; Litvintsev, D.; Lubimov, V.; Pakhlov, P.; Ratnikov, F.; Semenov, S.; Snizhko, A.; Soloshenko, V.; Tichomirov, I.; Zaitsev, Yu.

    1994-09-01

    Using the ARGUS detector at the e + e - storage ring DORIS II, flavour-dependent kaon production in B meson decays has been studied. Using the leptons as flavour tags, it has been possible to separately measure the multiplicities of K +, K - and K {/s 0} in inclusive B decays and in semileptonic B decays. The kaon production in semileptonic B decays was further used to estimate the ratio of charmed decays over all decays, and thus also the fraction of charmless B decays.

  13. Particle image velocimetry for an automatic cooling device using temperature-sensitive magnetic fluid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An automatic cooling device has been developed by using a temperature-sensitive magnetic fluid as the coolant. A particle image velocimetry (PIV) system was used to measure the flow velocity of the fluid inside the loop. The efficiency of the device under varying conditions such as the heat load and the power of cooling were ex- perimentally investigated. The effect of cooperation between external magnetic field and thermal field on the performance of the device was studied. As expected, a continuous flow induced by the thermal and magnetic field was observed in the loop, where heat was transferred by the circulating magnetic fluid. The synergic effect between the magnetic field and the temperature gradient has impact on the performance of the device.

  14. Zero-crossing detection algorithm for arrays of optical spatial filtering velocimetry sensors

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Pedersen, Finn; Hanson, Steen Grüner

    2008-01-01

    This paper presents a zero-crossing detection algorithm for arrays of compact low-cost optical sensors based on spatial filtering for measuring fluctuations in angular velocity of rotating solid structures. The algorithm is applicable for signals with moderate signal-to-noise ratios, and delivers...... a "real-time" output (0-1 kHz). The sensors use optical spatial-filtering velocimetry on the dynamical speckles arising from scattering off a rotating solid object with a non-specular surface. The technology measures the instantaneous angular velocity of a target, without being biased by any linear...... factor is directly related to the thermal expansion and refractive-index coefficients of the optics (> 10(-5) K-1 for glass). By cascade-coupling an array of sensors, the ensemble-averaged angular velocity is measured in "real-time". This will reduce the influence of pseudo-vibrations arising from...

  15. Spatial filtering velocimetry of objective speckles for measuring out-of-plane motion

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Yura, H. T.; Hanson, Steen Grüner

    2012-01-01

    This paper analyzes the dynamics of objective laser speckles as the distance between the object and the observation plane continuously changes. With the purpose of applying optical spatial filtering velocimetry to the speckle dynamics, in order to measure out-of-plane motion in real time...... discusses the selectivity of the spatial filter, the nonlinear response between speckle motion and observation distance, and the influence of the distance-dependent speckle size. Experiments with the emulated filters illustrate performance and potential applications of the technology......., a rotational symmetric spatial filter is designed. The spatial filter converts the speckle dynamics into a photocurrent with a quasi-sinusoidal response to the out-of-plane motion. The spatial filter is here emulated with a CCD camera, and is tested on speckles arising from a real application. The analysis...

  16. Far-Field Plasmonic Resonance Enhanced Nano-Particle Image Velocimetry within a Micro Channel

    CERN Document Server

    Zhang, Zhili; Haque, Sara S; Zhang, Mingjun

    2010-01-01

    In this paper, a novel far-field plasmonic resonance enhanced nanoparticle-seeded Particle Image Velocimetry (nPIV) has been demonstrated to measure the velocity profile in a micro channel. Chemically synthesized silver nanoparticles have been used to seed the flow in the micro channel. By using Discrete Dipole Approximation (DDA), plasmonic resonance enhanced light scattering has been calculated for spherical silver nanoparticles with diameters ranging from 15nm to 200nm. Optimum scattering wavelength is specified for the nanoparticles in two media: water and air. The diffraction-limited plasmonic resonance enhanced images of silver nanoparticles at different diameters have been recorded and analyzed. By using standard PIV techniques, the velocity profile within the micro channel has been determined from the images.

  17. The role of photographic parameters in laser speckle or particle image displacement velocimetry

    Science.gov (United States)

    Lourenco, L.; Krothapalli, A.

    1987-01-01

    The parameters involved in obtaining the multiple exposure photographs in the laser speckle velocimetry method (to record the light scattering by the seeding particles) were optimized. The effects of the type, concentration, and dimensions of the tracer, the exposure conditions (time between exposures, exposure time, and number of exposures), and the sensitivity and resolution of the film on the quality of the final results were investigated, photographing an experimental flow behind an impulsively started circular cylinder. The velocity data were acquired by digital processing of Young's fringes, produced by point-by-point scanning of a photographic negative. Using the optimal photographing conditions, the errors involved in the estimation of the fringe angle and spacing were of the order of 1 percent for the spacing and +/1 deg for the fringe orientation. The resulting accuracy in the velocity was of the order of 2-3 percent of the maximum velocity in the field.

  18. General-Purpose Stereo Imaging Velocimetry Technique Developed for Space and Industrial Applications

    Science.gov (United States)

    McDowell, Mark

    2004-01-01

    A new three-dimensional, full-field analysis technique has been developed for industrial and space applications. Stereo Imaging Velocimetry (SIV) will provide full-field analysis for three-dimensional flow data from any optically transparent fluid that can be seeded with tracer particles. The goal of SIV is to provide a means to measure three-dimensional fluid velocities quantitatively and qualitatively at many points. SIV is applicable to any optically transparent fluid experiment. Except for the tracer particles, this measurement technique is nonintrusive. Velocity accuracies are on the order of 95 to 99 percent of fullfield. The system components of SIV include camera calibration, centroid determination, overlap decomposition, particle tracking, stereo matching, and three-dimensional velocity analysis. SIV has been used successfully for space shuttle experiments as well as for fluid flow applications for business and industry.

  19. Particle image velocimetry correlation signal-to-noise ratio metrics and measurement uncertainty quantification

    CERN Document Server

    Xue, Zhenyu; Vlachos, Pavlos P

    2014-01-01

    In particle image velocimetry (PIV) the measurement signal is contained in the recorded intensity of the particle image pattern superimposed on a variety of noise sources. The signal-to-noise-ratio (SNR) strength governs the resulting PIV cross correlation and ultimately the accuracy and uncertainty of the resulting PIV measurement. Hence we posit that correlation SNR metrics calculated from the correlation plane can be used to quantify the quality of the correlation and the resulting uncertainty of an individual measurement. In this paper we present a framework for evaluating the correlation SNR using a set of different metrics, which in turn are used to develop models for uncertainty estimation. The SNR metrics and corresponding models presented herein are expanded to be applicable to both standard and filtered correlations. In addition, the notion of a valid measurement is redefined with respect to the correlation peak width in order to be consistent with uncertainty quantification principles and distinct ...

  20. Two-phase velocity measurements around cylinders using particle image velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Y.A.; Philip, O.G.; Schmidl, W.D. [Texas A& M Univ., College Station, TX (United States)] [and others

    1995-09-01

    The particle Image Velocimetry flow measurement technique was used to study both single-phase flow and two-phase flow across a cylindrical rod inserted in a channel. First, a flow consisting of only a single-phase fluid was studied. The experiment consisted of running a laminar flow over four rods inserted in a channel. The water flow rate was 126 cm{sup 3}/s. Then a two-phase flow was studied. A mixture of water and small air bubbles was used. The water flow rate was 378 cm{sup 3}/s and the air flow rate was approximately 30 cm{sup 3}/s. The data are analyzed to obtain the velocity fields for both experiments. After interpretation of the velocity data, forces acting on a bubble entrained by the vortex were calculated successfully. The lift and drag coefficients were calculated using the velocity measurements and the force data.

  1. Shear velocity and wall position determination from particle image velocimetry data with seed centroid correction

    Science.gov (United States)

    Harris, Jeff; Lance, Blake; Skifton, Richard; Smith, Barton

    2015-11-01

    Two methods of computing the wall shear velocity from high-resolution particle image velocimetry (PIV) measurements are compared with and without a correction that accounts for seed gradient near the wall. It is crucial to know the wall position when computing the wall shear stress, but this can be difficult due to laser scatter on a wall. Furthermore, PIV is well known to be biased near walls due to seeding gradients. We compensate for these effects by replacing the cross-stream location of each vector with a value based on the centroid of the seeding in each interrogation region. The shear velocity and wall position resulting from methods outlined in the literature are presented. The boundary layer cases presented are influenced by buoyancy and the efficacy of these methods for convective flow will be discussed.

  2. Consequences of spectrograph illumination for the accuracy of radial-velocimetry

    CERN Document Server

    Boisse, I; Chazelas, B; Perruchot, S; Pepe, F; Lovis, C; Hebrard, G

    2010-01-01

    For fiber-fed spectrographs with a stable external wavelength source, scrambling properties of optical fibers and, homogeneity and stability of the instrument illumination are important for the accuracy of radial-velocimetry. Optical cylindric fibers are known to have good azimuthal scrambling. In contrast, the radial one is not perfect. In order to improve the scrambling ability of the fiber and to stabilize the illumination, optical double scrambler are usually coupled to the fibers. Despite that, our experience on SOPHIE and HARPS has lead to identified remaining radial-velocity limitations due to the non-uniform illumination of the spectrograph. We conducted tests on SOPHIE with telescope vignetting, seeing variation and centering errors on the fiber entrance. We simulated the light path through the instrument in order to explain the radial velocity variation obtained with our tests. We then identified the illumination stability and uniformity has a critical point for the extremely high-precision radial v...

  3. Experimental study on fiber suspensions in a curved expansion duct with particle image velocimetry

    Directory of Open Access Journals (Sweden)

    Liang Xiao-Yu

    2012-01-01

    Full Text Available The visualization measurement of internal flow field in a curved expansion duct is experimentally studied using particle image velocimetry technology and the influence of flow rate on flow field is analyzed. The streamline distribution and related performance curve in the internal flow field can be figured out through further analysis of experiment data. The results show that fiber orientation is mainly affected by velocity gradient, the fibers near the wall are aligned with the flow direction more quickly than the fibers in intermediate region, and the fibers near the concave wall are more quickly aligned with the flow direction than the convex wall. The larger inlet flow rate which will accordingly lead to increase inlet velocity enables the more quick adaptation and steady of fibers in flow direction.

  4. Investigating fundamental properties of wind turbine wake structure using particle image velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Whale, J. [Univ. of Edinburgh, Dept. of Mechanical Engineering, Edinburgh (United Kingdom)

    1997-08-01

    Low Reynolds number flow visualization tests are often used for showing the flow pattern changes associated with changes in lift-coefficients at a higher Reynolds number. In wind turbine studies, analysis of measured wake structures at small scale may reveal fundamental properties of the wake which will offer wake modellers a more complete understanding of rotor flows. Measurements are presented from experiments on a model wind turbine rig conducted in a water channel. The laser-optics technique of Particle Image Velocimetry (PIV) is used to make simultaneous multi-point measurements of the wake flow behind small-scale rotors. Analysis of the PIV data shows trends in velocity and vorticity structure in the wake. Study of the flow close to the rotor plane reveals information on stalled flow and blade performance. (au)

  5. Three-dimensional particle image velocimetry for use in three-phase fluidization systems

    Science.gov (United States)

    Reese, J.; Chen, R. C.; Fan, L. S.

    1995-10-01

    A three-dimensional particle image velocimetry (3-DPIV) system is developed to measure the three-dimensional local flow properties of gas-liquid and gas-liquid-solid fluidization systems. The 3-DPIV system requires one camera to simultaneous record orthogonal views of the flow field created by a special optical arrangement. The 3-DPIV has been successfully calibrated and is capable of providing qualitative and quantitative flow information including three-dimensional, full-field, instantaneous velocities, accelerations and holdups of each phase. In this study, sample results of the application of the 3-DPIV technique to a three-dimensional gas-liquid-solid fluidization system operating in the dispersed bubble flow regime demonstrate that the 3-DPIV technique is an effective instrument in studying the local, transient flow phenomena in multiphase systems.

  6. Rainbow Particle Imaging Velocimetry for Dense 3D Fluid Velocity Imaging

    KAUST Repository

    Xiong, Jinhui

    2017-04-11

    Despite significant recent progress, dense, time-resolved imaging of complex, non-stationary 3D flow velocities remains an elusive goal. In this work we tackle this problem by extending an established 2D method, Particle Imaging Velocimetry, to three dimensions by encoding depth into color. The encoding is achieved by illuminating the flow volume with a continuum of light planes (a “rainbow”), such that each depth corresponds to a specific wavelength of light. A diffractive component in the camera optics ensures that all planes are in focus simultaneously. For reconstruction, we derive an image formation model for recovering stationary 3D particle positions. 3D velocity estimation is achieved with a variant of 3D optical flow that accounts for both physical constraints as well as the rainbow image formation model. We evaluate our method with both simulations and an experimental prototype setup.

  7. The application of digital particle image velocimetry (DPIV) to transonic flows

    Science.gov (United States)

    Bryanston-Cross, P. J.; Judge, T. R.; Quan, C.; Pugh, G.; Corby, N.

    The paper is an extension to earlier PIV work published in Progress in Aerospace Science Vol. 27, pp237-265. 1990. DPIV (Digital Particle Image Velocimetry) measurements have been made at transonic speeds using a new method of both digitally capturing and visualising high speed flow-fields. It has provided a quantitative whole field image of the transonic flow. The area of interest for this test was of the wing/pylon/nacelle/inboard gully region of a 5.7% scale model wing and engine combination. The measurements show velocity and flow angle changes in this region, to a measurement accuracy of 4%, made at an optical stand off distance of 0.5 m.

  8. Estimation of the measurement uncertainty in magnetic resonance velocimetry based on statistical models

    Energy Technology Data Exchange (ETDEWEB)

    Bruschewski, Martin; Schiffer, Heinz-Peter [Technische Universitaet Darmstadt, Institute of Gas Turbines and Aerospace Propulsion, Darmstadt (Germany); Freudenhammer, Daniel [Technische Universitaet Darmstadt, Institute of Fluid Mechanics and Aerodynamics, Center of Smart Interfaces, Darmstadt (Germany); Buchenberg, Waltraud B. [University Medical Center Freiburg, Medical Physics, Department of Radiology, Freiburg (Germany); Grundmann, Sven [University of Rostock, Institute of Fluid Mechanics, Rostock (Germany)

    2016-05-15

    Velocity measurements with magnetic resonance velocimetry offer outstanding possibilities for experimental fluid mechanics. The purpose of this study was to provide practical guidelines for the estimation of the measurement uncertainty in such experiments. Based on various test cases, it is shown that the uncertainty estimate can vary substantially depending on how the uncertainty is obtained. The conventional approach to estimate the uncertainty from the noise in the artifact-free background can lead to wrong results. A deviation of up to -75% is observed with the presented experiments. In addition, a similarly high deviation is demonstrated with the data from other studies. As a more accurate approach, the uncertainty is estimated directly from the image region with the flow sample. Two possible estimation methods are presented. (orig.)

  9. On the dynamics of jellyfish locomotion via 3D particle tracking velocimetry

    Science.gov (United States)

    Piper, Matthew; Kim, Jin-Tae; Chamorro, Leonardo P.

    2016-11-01

    The dynamics of jellyfish (Aurelia aurita) locomotion is experimentally studied via 3D particle tracking velocimetry. 3D locations of the bell tip are tracked over 1.5 cycles to describe the jellyfish path. Multiple positions of the jellyfish bell margin are initially tracked in 2D from four independent planes and individually projected in 3D based on the jellyfish path and geometrical properties of the setup. A cubic spline interpolation and the exponentially weighted moving average are used to estimate derived quantities, including velocity and acceleration of the jellyfish locomotion. We will discuss distinctive features of the jellyfish 3D motion at various swimming phases, and will provide insight on the 3D contraction and relaxation in terms of the locomotion, the steadiness of the bell margin eccentricity, and local Reynolds number based on the instantaneous mean diameter of the bell.

  10. Particle image velocimetry of active flow control on a compressor cascade

    Energy Technology Data Exchange (ETDEWEB)

    Hecklau, M.; Rennings, R. van; Zander, V.; Nitsche, W. [Technische Universitaet Berlin, Department of Aeronautics and Astronautics, Berlin (Germany); Huppertz, A.; Swoboda, M. [Rolls-Royce Deutschland Ltd. and Co. KG, Dahlewitz (Germany)

    2011-04-15

    AFC (Active Flow Control) experiments have been performed by means of steady and pulsed blowing out of the sidewalls as well as out of the blade's suction surface in a highly loaded compressor cascade. PIV (Particle Image Velocimetry) was used to evaluate the fully three-dimensional internal flow field and the impact of AFC methods. The aim was to observe the secondary flow structures and flow instabilities by PIV, to tune the AFC device operation parameters. This paper summarizes the different PIV measurements performed at the stator cascade to give an overview of the dominant flow features in the passage flow field and to obtain a detailed view of control mechanisms. In addition, a new vortex detection method is presented, based on a 2D-wavelet which is applicable in two-dimensional velocity data fields. (orig.)

  11. Study of fish response using particle image velocimetry and high-speed, high-resolution imaging

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Richmond, M. C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mueller, R. P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gruensch, G. R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2004-10-01

    Fish swimming has fascinated both engineers and fish biologists for decades. Digital particle image velocimetry (DPIV) and high-speed, high-resolution digital imaging are recently developed analysis tools that can help engineers and biologists better understand how fish respond to turbulent environments. This report details studies to evaluate DPIV. The studies included a review of existing literature on DPIV, preliminary studies to test the feasibility of using DPIV conducted at our Flow Biology Laboratory in Richland, Washington September through December 2003, and applications of high-speed, high-resolution digital imaging with advanced motion analysis to investigations of fish injury mechanisms in turbulent shear flows and bead trajectories in laboratory physical models. Several conclusions were drawn based on these studies, which are summarized as recommendations for proposed research at the end of this report.

  12. Measurement of velocity profiles of nanofluids in laminar channel flow using Particle Image Velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, Arun K.; Kulkarni, Parimal P.; Singh, R.K.; Verma, Pumendra [Bhabha Atomic Research Centre (BARC), Mumbai (India). Reactor Engineering Div.; Gandhi, Mayur [University Institute of Chemical Technology, Mumbai (India). Dept. of Chemical Engineering

    2014-06-15

    The objective of the paper is to measure the velocity profiles of water based nanofluids for flow through channels in order to understand whether the nanofluids behave Newtonian. For this purpose, experiments were carried for flow through a rectangular channel in laminar regime. Four different nanofluids were used, i.e. Al{sub 2}O{sub 3}, CuO, TiO{sub 2} and SiO{sub 2} with base fluid as water. Experiments were conducted at low concentration of these particles. The velocity profiles were measured using Particle Image Velocimetry. The results indicate that the velocity profiles are similar for all the fluids indicating the flows to be Newtonian. (orig.)

  13. Flowfield characterization of a piloted lean premixed injector by particle image velocimetry

    Science.gov (United States)

    Berdanier, Catherine G. P.

    Limiting atmospheric pollution, especially nitrous oxides, is an important endeavor for aviation technology companies. Technology-driving regulations from the International Civil Aviation Organization's (ICAO) Committee of Aviation Environmental Protection (CAEP) standards spur the combustion research and development community to find innovative engine technologies to decrease emissions in the coming years. As engine technologies are developed, testing is necessary to verify combustion models and expected flow patterns. Optical diagnostics provide a unique opportunity to visualize flowfields in complex practical combustor systems. For this thesis, Particle Image Velocimetry (PIV) was employed to characterize the flowfield in a piloted lean premixed injector under non-combusting conditions. Planes of PIV data were acquired at five spanwise locations and two streamwise locations, at two different pressure conditions in order to characterize the flowfields and structures throughout the optically accessible flowpath. Average velocity maps and time-resolved vector fields at these planes were analyzed for this thesis.

  14. Particle Data Management Software for 3DParticle Tracking Velocimetry and Related Applications – The Flowtracks Package

    Directory of Open Access Journals (Sweden)

    Yosef Meller

    2016-06-01

    Full Text Available The Particle Tracking Velocimetry (PTV community employs several formats of particle information such as position and velocity as function of time, i.e. trajectory data, as a result of diverging needs unmet by existing formats, and a number of different, mostly home-grown, codes for handling the data. Flowtracks is a Python package that provides a single code base for accessing different formats as a database, i.e. storing data and programmatically manipulating them using format-agnostic data structures. Furthermore, it offers an HDF5-based format that is fast and extensible, obviating the need for other formats. The package may be obtained from https://github.com/OpenPTV/postptv and used as-is by many fluid-dynamics labs, or with minor extensions adhering to a common interface, by researchers from other fields, such as biology and population tracking.

  15. Holographic particle image velocimetry measurements of hairpin vortices in a subcritical air channel flow

    Science.gov (United States)

    Svizher, Alexander; Cohen, Jacob

    2006-01-01

    A holographic particle image velocimetry (HPIV) system is employed to study the evolution of coherent structures artificially generated in a plane Poiseuille air flow. As a first step the hot-wire technique and two-dimensional flow visualization are used to determine the generation conditions and dimensions of the coherent structures, their shedding frequency, trajectory, and convection velocity. Then, the HPIV method is utilized to obtain the instantaneous topology of the hairpin vortex and its associated three-dimensional distribution of the two (streamwise and spanwise) velocity components as well as the corresponding wall-normal vorticity. Finally, the experimental data are compared with results of related experimental and numerical studies. The present experimental results support the view that the generation of hairpins under various base flow conditions is governed by a basic mechanism, the important common elements of which are the shear of the base flow and an initial disturbance having a sufficiently large amplitude.

  16. TECHNICAL DESIGN NOTE Multi-pass light amplification for tomographic particle image velocimetry applications

    Science.gov (United States)

    Ghaemi, Sina; Scarano, Fulvio

    2010-12-01

    The light source budget is a critical issue for tomographic particle image velocimetry (Tomo-PIV) systems due to its requirement for large illuminated volume and imaging at small apertures. In this work, a light amplification system based on the multi-pass concept is investigated for Tomo-PIV applications. The system design is performed on the basis of a theoretical model providing an estimation of the most important system parameters and above all the amplification gain. The multi-pass light amplification concept is verified experimentally by measuring the scattered light intensity across the illuminated volume. The results demonstrate a gain factor of 7 and 5 times in comparison with the single-pass and double-pass illumination approaches, respectively.

  17. Tomographic particle image velocimetry over a triangular prism in unidirectional flows

    Science.gov (United States)

    Sou, In Mei; Calantoni, Joseph

    2011-11-01

    Using tomographic particle image velocimetry (Tomo-PIV), the full three-dimensional-three-component (3D-3C) flow structure and turbulence characteristics over a triangular prism in a recirculating water tunnel were investigated. Here we present preliminary results from a new Tomo-PIV system for subcritical Froude number flows. Large-scale vortex shedding from the tip of the triangular prism is observed. Results of coherent structure organization analyzed by 3D vorticity calculation will be presented. Using the full 3D-3C instantaneous velocity field, turbulent kinetic energy is directly evaluated without any of the assumptions often needed for 2D PIV measurements. Details of the experimental setup including a unique device designed to perform our Tomo-PIV volume calibration will be discussed. We perform an in-depth turbulent kinetic energy budget and explore the feasibility of extending the measurement technique to other complex flows.

  18. Laser-Doppler Velocimetry Measurements Inside a Backward Curved Centrifugal Fan

    Directory of Open Access Journals (Sweden)

    Tong-Miin Liou

    2001-01-01

    Full Text Available Laser-Doppler velocimetry (LDV measurements are presented of relative mean velocity and turbulence intensity components inside the impeller passage of a centrifugal fan with twelve backward curved blades at design, under-design, and over-design flow rates. Additional LDV measurements were also performed at the volute outlet to examine the uniformity of the outlet flow for the three selected flow rates. Complementary flow visualization results in the tongue region are further presented. It is found that the number of characteristic flow regions and the average turbulence level increase with decreasing air flow rate. For the case of under-design flow rate, there are a through-flow region on the suction side, a reverse flow region on the pressure side, and a shear layer region in between. The corresponding average turbulence intensity is as high as 9.1% of blade tip velocity.

  19. Development of a Diver-Operated Single Camera Volumetric Velocimetry System

    Science.gov (United States)

    Troutman, Valerie; Dabiri, John

    2016-11-01

    The capabilities of a single camera, volumetric velocimetry system for in situ measurement in marine environments are demonstrated by imaging a well-characterized flow in a laboratory environment. This work represents the first stages in the design of a SCUBA-diver operated system to study organisms and biological processes under the natural light in the water column. This system is primarily composed of a volumetric particle tracking diagnostic to investigate fluid-animal interactions. A target domain size of a 20 cm sided cube is sought as a key design feature for the capability of capturing the flow around a variety of benthic and freely swimming organisms. The integration of the particle tracking system with additional diagnostics will be discussed.

  20. Micro-particle image velocimetry for velocity profile measurements of micro blood flows.

    Science.gov (United States)

    Pitts, Katie L; Fenech, Marianne

    2013-04-25

    Micro-particle image velocimetry (μPIV) is used to visualize paired images of micro particles seeded in blood flows. The images are cross-correlated to give an accurate velocity profile. A protocol is presented for μPIV measurements of blood flows in microchannels. At the scale of the microcirculation, blood cannot be considered a homogeneous fluid, as it is a suspension of flexible particles suspended in plasma, a Newtonian fluid. Shear rate, maximum velocity, velocity profile shape, and flow rate can be derived from these measurements. Several key parameters such as focal depth, particle concentration, and system compliance, are presented in order to ensure accurate, useful data along with examples and representative results for various hematocrits and flow conditions.

  1. Particle image velocimetry for an automatic cooling device using temperature-sensitive magnetic fluid

    Institute of Scientific and Technical Information of China (English)

    LIAN WenLei; LI Qiang; XUAN YiMin

    2008-01-01

    An automatic cooling device has been developed by using a temperature-sensitive magnetic fluid as the coolant. A particle image velocimetry (PIV) system was used to measure the flow velocity of the fluid inside the loop. The efficiency of the device under varying conditions such as the heat load and the power of cooling were ex-perimentally investigated. The effect of cooperation between external magnetic field and thermal field on the performance of the device was studied. As expected, a continuous flow induced by the thermal and magnetic field was observed in the loop, where heat was transferred by the circulating magnetic fluid. The synergic effect between the magnetic field and the temperature gradient has impact on the performance of the device.

  2. The complex aerodynamic footprint of desert locusts revealed by large-volume tomographic particle image velocimetry.

    Science.gov (United States)

    Henningsson, Per; Michaelis, Dirk; Nakata, Toshiyuki; Schanz, Daniel; Geisler, Reinhard; Schröder, Andreas; Bomphrey, Richard J

    2015-07-01

    Particle image velocimetry has been the preferred experimental technique with which to study the aerodynamics of animal flight for over a decade. In that time, hardware has become more accessible and the software has progressed from the acquisition of planes through the flow field to the reconstruction of small volumetric measurements. Until now, it has not been possible to capture large volumes that incorporate the full wavelength of the aerodynamic track left behind during a complete wingbeat cycle. Here, we use a unique apparatus to acquire the first instantaneous wake volume of a flying animal's entire wingbeat. We confirm the presence of wake deformation behind desert locusts and quantify the effect of that deformation on estimates of aerodynamic force and the efficiency of lift generation. We present previously undescribed vortex wake phenomena, including entrainment around the wing-tip vortices of a set of secondary vortices borne of Kelvin-Helmholtz instability in the shear layer behind the flapping wings.

  3. Particle Image Velocimetry Measurment of Flow Across Tube Bundle in Waste Heat Boiler

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the present paper the experimental investigations of flow across staggered tube bundles in waste heat boiler are conducted by mans of PIV (Particle Image Velocimetry)system,Flow visualization and velocity distribution of the wake between different cylinders are measured in detail.It is concluded that there are still Von Karman vortices in the wake and the phenomenas of vortex shedding,pairing,merging are observed in the flow.The Von Karman vortices can't fully developed because of the existence of the downstream cylinder.There is interaction between main streams and vortices,and the development of the vortex is enhanced by this interaction.Meanwhile some statistical results are performed.The distribution of correlated variables of the velocity fluctuations μ′μ′,μ′ν′,ν′ν′ and the space correlation coefficients are obtained.

  4. A Phosphorylation Tag for Uranyl Mediated Protein Purification and Photo Assisted Tag Removal

    DEFF Research Database (Denmark)

    Zhang, Qiang; Jørgensen, Thomas. J. D.; Nielsen, Peter E;

    2014-01-01

    enables target protein purification from an E. coli extract by immobilized uranyl affinity chromatography. Subsequently, the tag can be efficiently removed by UV-irradiation assisted uranyl photocleavage. We therefore suggest that the divalent uranyl ion (UO22+) may provide a dual function in protein...

  5. Tags Help Make Libraries Del.icio.us: Social Bookmarking and Tagging Boost Participation

    Science.gov (United States)

    Rethlefsen, Melissa L.

    2007-01-01

    Traditional library web products, whether online public access catalogs, library databases, or even library web sites, have long been rigidly controlled and difficult to use. Patrons regularly prefer Google's simple interface. Now social bookmarking and tagging tools help librarians bridge the gap between the library's need to offer authoritative,…

  6. Behavioral Tagging: A Translation of the Synaptic Tagging and Capture Hypothesis

    Science.gov (United States)

    Moncada, Diego; Ballarini, Fabricio; Viola, Haydée

    2015-01-01

    Similar molecular machinery is activated in neurons following an electrical stimulus that induces synaptic changes and after learning sessions that trigger memory formation. Then, to achieve perdurability of these processes protein synthesis is required for the reinforcement of the changes induced in the network. The synaptic tagging and capture theory provided a strong framework to explain synaptic specificity and persistence of electrophysiological induced plastic changes. Ten years later, the behavioral tagging hypothesis (BT) made use of the same argument, applying it to learning and memory models. The hypothesis postulates that the formation of lasting memories relies on at least two processes: the setting of a learning tag and the synthesis of plasticity related proteins, which once captured at tagged sites allow memory consolidation. BT explains how weak events, only capable of inducing transient forms of memories, can result in lasting memories when occurring close in time with other behaviorally relevant experiences that provide proteins. In this review, we detail the findings supporting the existence of BT process in rodents, leading to the consolidation, persistence, and interference of a memory. We focus on the molecular machinery taking place in these processes and describe the experimental data supporting the BT in humans. PMID:26380117

  7. Behavioral Tagging: A Translation of the Synaptic Tagging and Capture Hypothesis

    Directory of Open Access Journals (Sweden)

    Diego Moncada

    2015-01-01

    Full Text Available Similar molecular machinery is activated in neurons following an electrical stimulus that induces synaptic changes and after learning sessions that trigger memory formation. Then, to achieve perdurability of these processes protein synthesis is required for the reinforcement of the changes induced in the network. The synaptic tagging and capture theory provided a strong framework to explain synaptic specificity and persistence of electrophysiological induced plastic changes. Ten years later, the behavioral tagging hypothesis (BT made use of the same argument, applying it to learning and memory models. The hypothesis postulates that the formation of lasting memories relies on at least two processes: the setting of a learning tag and the synthesis of plasticity related proteins, which once captured at tagged sites allow memory consolidation. BT explains how weak events, only capable of inducing transient forms of memories, can result in lasting memories when occurring close in time with other behaviorally relevant experiences that provide proteins. In this review, we detail the findings supporting the existence of BT process in rodents, leading to the consolidation, persistence, and interference of a memory. We focus on the molecular machinery taking place in these processes and describe the experimental data supporting the BT in humans.

  8. Social tagging in support of cancer patients’ information interaction

    DEFF Research Database (Denmark)

    Ådland, Marit Kristine; Lykke, Marianne

    2012-01-01

    and analyzed literature about cancer patients’ information needs and seeking behavior, and about social tagging and patient terminology. Secondly, we analyzed tags applied to blog postings at Blogomkraeft.dk, a blog site at the Danish information web site Cancer.dk. The tags were compared with the formal...... browsing structure of Cancer.dk. Results from the two studies were used to develop a prototype for social tagging at Cancer.dk. Thus thirdly, we evaluated the prototype in a usability study. Findings: We found that tags have the potential to describe and provide access to web site content from the users...... to documents, reflecting their own model of the current topic. Tags may furthermore function as colloquial lead-in terms from users’ search formulations at search engines such as Google to the domain-specific, tailored cancer web site....

  9. Nanoparticle flow velocimetry with image phase correlation for confocal laser scanning microscopy

    Science.gov (United States)

    Jun, Brian H.; Giarra, Matthew; Yang, Haisheng; Main, Russell; Vlachos, Pavlos P.

    2016-10-01

    We present a new particle image correlation technique for resolving nanoparticle flow velocity using confocal laser scanning microscopy (CLSM). The two primary issues that complicate nanoparticle scanning laser image correlation (SLIC)-based velocimetry are (1) the use of diffusion-dominated nanoparticles as flow tracers, which introduce a random decorrelating error into the velocity estimate, and (2) the effects of the scanning laser image acquisition, which introduces a bias error. To date, no study has quantified these errors or demonstrated a means to deal with them in SLIC velocimetry. In this work, we build upon the robust phase correlation (RPC) and existing methods of SLIC to quantify and mitigate these errors. First, we implement an ensemble RPC instead of using an ensemble standard cross-correlation, and develop a SLIC optimal filter that maximizes the correlation strength in order to reliably and accurately detect the correlation peak representing the most probable average displacement of the nanoparticles. Secondly, we developed an analytical model of the SLIC measurement bias error due to image scanning of diffusion-dominated tracer particles. We show that the bias error depends only on the ratio of the mean velocity of the tracer particles to that of the laser scanner and we use this model to correct the induced errors. We validated our technique using synthetic images and experimentally obtained SLIC images of nanoparticle flow through a micro-channel. Our technique reduced the error by up to a factor of ten compared to other SLIC algorithms for the images tested in this study. Moreover, our optimized RPC filter reduces the number of image pairs required for the convergence of the ensemble correlation by two orders of magnitude compared to the standard cross correlation. This feature has broader implications to ensemble correlation methods and should be further explored in depth in the future.

  10. Volumetric intake flow measurements of an IC engine using magnetic resonance velocimetry

    Science.gov (United States)

    Freudenhammer, Daniel; Baum, Elias; Peterson, Brian; Böhm, Benjamin; Jung, Bernd; Grundmann, Sven

    2014-05-01

    Magnetic resonance velocimetry (MRV) measurements are performed in a 1:1 scale model of a single-cylinder optical engine to investigate the volumetric flow within the intake and cylinder geometry during flow induction. The model is a steady flow water analogue of the optical IC-engine with a fixed valve lift of mm to simulate the induction flow at crank-angle bTDC. This setup resembles a steady flow engine test bench configuration. MRV measurements are validated with phase-averaged particle image velocimetry (PIV) measurements performed within the symmetry plane of the optical engine. Differences in experimental operating parameters between MRV and PIV measurements are well addressed. Comparison of MRV and PIV measurements is demonstrated using normalized mean velocity component profiles and showed excellent agreement in the upper portion of the cylinder chamber (i.e., mm). MRV measurements are further used to analyze the ensemble average volumetric flow within the 3D engine domain. Measurements are used to describe the 3D overflow and underflow behavior as the annular flow enters the cylinder chamber. Flow features such as the annular jet-like flows extending into the cylinder, their influence on large-scale in-cylinder flow motion, as well as flow recirculation zones are identified in 3D space. Inlet flow velocities are analyzed around the entire valve curtain perimeter to quantify percent mass flow rate entering the cylinder. Recirculation zones associated with the underflow are shown to reduce local mass flow rates up to 50 %. Recirculation zones are further analyzed in 3D space within the intake manifold and cylinder chamber. It is suggested that such recirculation zones can have large implications on cylinder charge filling and variations of the in-cylinder flow pattern. MRV is revealed to be an important diagnostic tool used to understand the volumetric induction flow within engine geometries and is potentially suited to evaluate flow changes due to intake

  11. A micro particle shadow velocimetry (μPSV) technique to measure flows in microchannels

    Science.gov (United States)

    Khodaparast, Sepideh; Borhani, Navid; Tagliabue, Giulia; Thome, John Richard

    2013-02-01

    A micro particle shadow velocimetry (μPSV) system based on back-lit illumination and forward scatter observation of light from non-fluorescent particles has been developed. Relatively high luminous efficiencies and particle image contrasts were achieved by using the condenser stage of a standard transmitted light microscope and a continuous incoherent collimated light emitting diode (LED). This paper includes a critical review of the operating principles, benefits and practical problems associated with the predominant epifluorescent micro particle image velocimetry (μPIV) technique, and the less common light scattering μPIV methods of which μPSV is a development. This μPSV system was then successfully used to measure axial velocity profiles in a 280-μm-diameter circular channel up to a Reynolds number of 50 which corresponds to peak velocities of around 0.4 m/s. These velocity profiles were then integrated to provide instantaneous flow rates on the order of 100 μl/min to an accuracy of ±5 % relative to average flow rates determined using a digital balance. Due to the incoherent nature of the LED light source, the back-lit forward scatter observation mode and the applied refractive index matching system, the location of the test section walls and thus the local velocity fields were also accurately obtained. As a result of this, μPSV provides a low cost and safe way to investigate microfluidics, especially in lab-on-a-chip applications where the necessary optical access through transparent test sections is often available.

  12. A comprehensive statistical investigation of schlieren image velocimetry (SIV) using high-velocity helium jet

    Science.gov (United States)

    Biswas, Sayan; Qiao, Li

    2017-03-01

    A detailed statistical assessment of seedless velocity measurement using Schlieren Image Velocimetry (SIV) was explored using open source Robust Phase Correlation (RPC) algorithm. A well-known flow field, an axisymmetric turbulent helium jet, was analyzed near and intermediate region (0≤ x/d≤ 20) for two different Reynolds numbers, Re d = 11,000 and Re d = 22,000 using schlieren with horizontal knife-edge, schlieren with vertical knife-edge and shadowgraph technique, and the resulted velocity fields from SIV techniques were compared to traditional Particle Image Velocimetry (PIV) measurements. A novel, inexpensive, easy to setup two-camera SIV technique had been demonstrated to measure high-velocity turbulent jet, with jet exit velocities 304 m/s (Mach = 0.3) and 611 m/s (Mach = 0.6), respectively. Several image restoration and enhancement techniques were tested to improve signal to noise ratio (SNR) in schlieren and shadowgraph images. Processing and post-processing parameters for SIV techniques were examined in detail. A quantitative comparison between self-seeded SIV techniques and traditional PIV had been made using correlation statistics. While the resulted flow field from schlieren with horizontal knife-edge and shadowgraph showed excellent agreement with PIV measurements, schlieren with vertical knife-edge performed poorly. The performance of spatial cross-correlations at different jet locations using SIV techniques and PIV was evaluated. Turbulence quantities like turbulence intensity, mean velocity fields, Reynolds shear stress influenced spatial correlations and correlation plane SNR heavily. Several performance metrics such as primary peak ratio (PPR), peak to correlation energy (PCE), the probability distribution of signal and noise were used to compare capability and potential of different SIV techniques.

  13. Diagnosis of Placenta Accreta by Uterine Artery Doppler Velocimetry in Patients With Placenta Previa.

    Science.gov (United States)

    Cho, Hee Young; Hwang, Han Sung; Jung, Inkyung; Park, Yong Won; Kwon, Ja-Young; Kim, Young Han

    2015-09-01

    To evaluate the potential value of uterine artery Doppler velocimetry in diagnosing placenta accreta. Clinical records of all deliveries between April 1991 and March 2013 were retrospectively analyzed. Cases of intrauterine growth restriction, pregnancy-induced hypertension, multiple pregnancies, fetal anomalies, chromosomal abnormalities, and maternal medical illnesses such as cardiovascular disease, renal disease, and diabetes mellitus were excluded. A total of 11,210 cases were evaluated, including 403 cases of placenta previa without accreta (placenta previa) and 39 cases of placenta previa with accreta (placenta accreta). All patients underwent uterine artery Doppler velocimetry to measure the mean resistive index and pulsatility index (PI) in the third trimester. The analysis included participant characteristics such as age, parity, abortion history, previous cesarean delivery, gestational age at delivery, neonatal sex, and birth weight. The mean uterine artery PI was significantly lower in the placenta accreta group compared to previa alone (0.51 versus 0.57; P = .002). The odds ratios for placenta accreta were 2.4 for 2 or more previous abortions (P = .011) and 5.3 and 7.0 for 1 and 2 or more previous cesarean deliveries (P = .001 and .005). With an increase in the mean PI by 0.01, the odds ratio for placenta accreta decreased by 0.94 (P placenta accreta compared to those without accreta. The diagnostic accuracy of placenta accreta can be potentially improved if uterine artery Doppler values and the history of cesarean delivery are combined. © 2015 by the American Institute of Ultrasound in Medicine.

  14. Analysis of Transitional and Turbulent Flow Through the FDA Benchmark Nozzle Model Using Laser Doppler Velocimetry.

    Science.gov (United States)

    Taylor, Joshua O; Good, Bryan C; Paterno, Anthony V; Hariharan, Prasanna; Deutsch, Steven; Malinauskas, Richard A; Manning, Keefe B

    2016-09-01

    Transitional and turbulent flow through a simplified medical device model is analyzed as part of the FDA's Critical Path Initiative, designed to improve the process of bringing medical products to market. Computational predictions are often used in the development of devices and reliable in vitro data is needed to validate computational results, particularly estimations of the Reynolds stresses that could play a role in damaging blood elements. The high spatial resolution of laser Doppler velocimetry (LDV) is used to collect two component velocity data within the FDA benchmark nozzle model. Two flow conditions are used to produce flow encompassing laminar, transitional, and turbulent regimes, and viscous stresses, principal Reynolds stresses, and turbulence intensities are calculated from the measured LDV velocities. Axial velocities and viscous stresses are compared to data from a prior inter-laboratory study conducted with particle image velocimetry. Large velocity gradients are observed near the wall in the nozzle throat and in the jet shear layer located in the expansion downstream of the throat, with axial velocity changing as much as 4.5 m/s over 200 μm. Additionally, maximum Reynolds shear stresses of 1000-2000 Pa are calculated in the high shear regions, which are an order of magnitude higher than the peak viscous shear stresses (<100 Pa). It is important to consider the effects of both viscous and turbulent stresses when simulating flow through medical devices. Reynolds stresses above commonly accepted hemolysis thresholds are measured in the nozzle model, indicating that hemolysis may occur under certain flow conditions. As such, the presented turbulence quantities from LDV, which are also available for download at https://fdacfd.nci.nih.gov/ , provide an ideal validation test for computational simulations that seek to characterize the flow field and to predict hemolysis within the FDA nozzle geometry.

  15. Particle image velocimetry measurements of 2-dimensional velocity field around twisted tape

    Energy Technology Data Exchange (ETDEWEB)

    Song, Min Seop; Park, So Hyun; Kim, Eung Soo, E-mail: kes7741@snu.ac.kr

    2016-11-01

    Highlights: • Measurements of the flow field in a pipe with twisted tape were conducted by particle image velocimetry (PIV). • A novel matching index of refraction technique utilizing 3D printing and oil mixture was adopted to make the test section transparent. • Undistorted particle images were clearly captured in the presence of twisted tape. • 2D flow field in the pipe with twisted tape revealed the characteristic two-peak velocity profile. - Abstract: Twisted tape is a passive component used to enhance heat exchange in various devices. It induces swirl flow that increases the mixing of fluid. Thus, ITER selected the twisted tape as one of the candidates for turbulence promoting in the divertor cooling. Previous study was mainly focused on the thermohydraulic performance of the twisted tape. As detailed data on the velocity field around the twisted tape was insufficient, flow visualization study was performed to provide fundamental data on velocity field. To visualize the flow in a complex structure, novel matching index of refraction technique was used with 3-D printing and mixture of anise and mineral oil. This technique enables the camera to capture undistorted particle image for velocity field measurement. Velocity fields at Reynolds number 1370–9591 for 3 different measurement plane were obtained through particle image velocimetry. The 2-dimensional averaged velocity field data were obtained from 177 pair of instantaneous velocity fields. It reveals the characteristic two-peak flow motion in axial direction. In addition, the normalized velocity profiles were converged with increase of Reynolds numbers. Finally, the uncertainty of the result data was analyzed.

  16. Word Sense Disambiguation using Conceptual Density

    CERN Document Server

    Agirre, E; Agirre, Eneko; Rigau, German

    1996-01-01

    This paper presents a method for the resolution of lexical ambiguity of nouns and its automatic evaluation over the Brown Corpus. The method relies on the use of the wide-coverage noun taxonomy of WordNet and the notion of conceptual distance among concepts, captured by a Conceptual Density formula developed for this purpose. This fully automatic method requires no hand coding of lexical entries, hand tagging of text nor any kind of training process. The results of the experiments have been automatically evaluated against SemCor, the sense-tagged version of the Brown Corpus.

  17. Hypergraph topological quantities for tagged social networks

    Science.gov (United States)

    Zlatić, Vinko; Ghoshal, Gourab; Caldarelli, Guido

    2009-09-01

    Recent years have witnessed the emergence of a new class of social networks, which require us to move beyond previously employed representations of complex graph structures. A notable example is that of the folksonomy, an online process where users collaboratively employ tags to resources to impart structure to an otherwise undifferentiated database. In a recent paper, we proposed a mathematical model that represents these structures as tripartite hypergraphs and defined basic topological quantities of interest. In this paper, we extend our model by defining additional quantities such as edge distributions, vertex similarity and correlations as well as clustering. We then empirically measure these quantities on two real life folksonomies, the popular online photo sharing site Flickr and the bookmarking site CiteULike. We find that these systems share similar qualitative features with the majority of complex networks that have been previously studied. We propose that the quantities and methodology described here can be used as a standard tool in measuring the structure of tagged networks.

  18. Stacking from Tags: Clustering Bookmarks around a Theme

    OpenAIRE

    Zubiaga, Arkaitz; García-Plaza, Alberto Pérez; Fresno, Víctor; Martínez, Raquel

    2013-01-01

    Since very recently, users on the social bookmarking service Delicious can stack web pages in addition to tagging them. Stacking enables users to group web pages around specific themes with the aim of recommending to others. However, users still stack a small subset of what they tag, and thus many web pages remain unstacked. This paper presents early research towards automatically clustering web pages from tags to find stacks and extend recommendations.

  19. Boosting b-tagging performance at high transverse momentum

    CERN Document Server

    Koshelenko, Daria

    2017-01-01

    B-tagging algorithms play a vital role in many physics analysis. Increasing of the collision energy in the Run 2 data led to a substantial increase of the flight length of b-hadrons, which makes the b-tagging process more complicated. In this paper, the studying of improving the b-tagging algorithm by using the number of clusters in Insertable b-layer and a Pixel Detector of the ATLAS detector is presented.

  20. Multi-tag content access control in RFID system

    OpenAIRE

    2010-01-01

    Radio Frequency Identification (RFID) makes great flexibility and high efficiency for data acquisition in industry and daily life. At the other side, it brings the privacy risks and multiple tags collision issue. Current research in RFID system focuses on the security and privacy issue which is based on authentication protocols between a tag and a Reader. There is a need to design a reasonable protocol which takes care of both multi-tag anti-collision and security issue. This thesis presen...

  1. Diffusion-Based Recommendation in Collaborative Tagging Systems

    Institute of Scientific and Technical Information of China (English)

    SHANG Ming-Sheng; ZHANG Zi-Ke

    2009-01-01

    Recently, collaborative tagging systems have attracted more and more attention and have been widely applied in web systems. Tags provide highly abstracted information about personal preferences and item content, and therefore have the potential to help in improving better personalized recommendations. We propose a diffusion-based recommendation algorithm considering the personal vocabulary and evaluate it in a real-world dataset: Del.icio.us. Experimental results demonstrate that the usage of tag information can significantly improve the accuracy of personalized recommendations.

  2. Symmetric Encryption Based Privacy using Lightweight Cryptography for RFID Tags

    OpenAIRE

    2015-01-01

    RFID technology emerged as the promising technology for its ease of use and implementation in the ubiquitous computing world. RFID is deployed widely in various applications that use automatic identification and processing for information retrieval. The primary components of an RFID system are the RFID tag (active and passive), the reader and the back-end server (database). Cost is the main factor that drove RFID tags to its immense utilization in which passive tags dominate in...

  3. A Personalized Tag-Based Recommendation in Social Web Systems

    DEFF Research Database (Denmark)

    Durao, Frederico; Dolog, Peter

    2009-01-01

    Tagging activity has been recently identified as a potential source of knowledge about personal interests, preferences, goals, and other attributes known from user models. Tags themselves can be therefore used for finding personalized recommendations of items. In this paper, we present a tag...... to study and evaluate the recommender system, we have conducted an experiment involving 38 people from 12 countries using data from Del.icio.us , a social bookmarking web system on which users can share their personal bookmarks...

  4. Flavor Tagging at Tevatron incl. calibration and control

    OpenAIRE

    2007-01-01

    This report summarizes the flavor tagging techniques developed at the CDF and D{\\O}experiments. Flavor tagging involves identification of the B meson flavor atproduction, whether its constituent is a quark or an anti-quark. It is crucial for measuring the oscillation frequency of neutral B mesons, both in the B^0 and B_S system. The two experiments have developed their unique approaches to flavor tagging, using neural networks, and likelihood methods to disentangle tracks from $b$ decays from...

  5. Recommending Tags for New Resources in Social Bookmarking Systems

    Directory of Open Access Journals (Sweden)

    Shweta Yagnik

    2014-04-01

    Full Text Available Social bookmarking system is a web-based resource sharing system that allows users to upload, share and organize their resources i.e. bookmarks and publications. The system has shifted the paradigm of bookmarking from an individual activity limited to desktop to a collective activity on the web. It also facilitates user to annotate his resource with free form tags that leads to large communities of users to collaboratively create accessible repositories of web resources. Tagging process has its own challenges like ambiguity, redundancy or misspelled tags and sometimes user tends to avoid it as he has to describe tag at his own. The resultant tag space is noisy or very sparse and dilutes the purpose of tagging. The effective solution is Tag Recommendation System that automatically suggests appropriate set of tags to user while annotating resource. In this paper, we propose a framework that does not depend on tagging history of the resource or user and thereby capable of suggesting tags to the resources which are being submitted to the system first time. We model tag recommendation task as multi-label text classification problem and use Naive Bayes classifier as the baselearner of the multilabel classifier. We experiment with Boolean, bag-of-words and term frequency-inverse document frequency (TFIDF representation of the resources and fit appropriate distribution to the data based on the representation used. Impact of featureselection on the effectiveness of the tag recommendation is also studied. Effectiveness of the proposed framework is evaluated through precision, recall and f-measure metrics.

  6. Application of PUF-Enabled RFID Tags in Electronic Banking

    Directory of Open Access Journals (Sweden)

    Saeed Mehmandoust

    2011-04-01

    Full Text Available Radio Frequency Identification (RFID tags have a variety of applications in e-banking. For effectiveutilization of the technology, this should be reinforced toward security holes and attacks. One of thecommon attacks on RFID systems is RFID tags cloning. In this paper we review cloning attacks in ebanking.We propose solutions based on physical unclonable functions (PUF and provide a suitablesecurity protocol for tag authentication in off-line environments.

  7. Some Fundamental Limits on SAW RFID Tag Information Capacity and Collision Resolution

    Science.gov (United States)

    Barton, Richard J.

    2013-01-01

    In this paper, we apply results from multi-user information theory to study the limits of information capacity and collision resolution for SAW RFID tags. In particular, we derive bounds on the achievable data rate per tag as a function of fundamental parameters such as tag time-bandwidth product, tag signal-to-noise ratio (SNR), and number of tags in the environment. We also discuss the implications of these bounds for tag waveform design and tag interrogation efficiency

  8. Tag cloud generation for results of multiple keywords queries

    DEFF Research Database (Denmark)

    2013-01-01

    In this paper we study tag cloud generation for retrieved results of multiple keyword queries. It is motivated by many real world scenarios such as personalization tasks, surveillance systems and information retrieval tasks defined with multiple keywords. We adjust the state-of-the-art tag cloud...... generation techniques for multiple keywords query results. Consequently, we conduct the extensive evaluation on top of three distinct collaborative tagging systems. The graph-based methods perform significantly better for the Movielens and Bibsonomy datasets. Tag cloud generation based on maximal coverage...

  9. Using TAGs to Speed up the ATLAS Analysis Process

    CERN Document Server

    Ehrenfeld, W; Cranshaw, J; Cuhadar Donszelmann, T; Doherty, T; Gallas, E; Hrivnac, J; Malon, D; Nowak, M; Slater, M; Viegas, F; Vinek, E; Zhang, Q

    2011-01-01

    In the ATLAS experiment, Tag Data, or short TAG, are event-level metadata -- thumbnail information about events to support efficient identification and selection of events of interest to a given analysis. TAG quantities range from detector status and trigger information to basic physics quantities, e. g. the number of loose electrons candidates and kinematic information for a limited number of these candidates sorted by their transverse momentum. The average TAG size per event is around 1kB, which is a factor 100 smaller than the Analysis Object Data (AOD) used for physics analysis. TAGs are primarily produced from AODs and stored in ROOT files. For easier access and usability TAGs are also stored in a database. Queries to the database can produce again TAG files. In a standard ATLAS analysis job, TAGs can be used to preselect events based on the TAG quantities before accessing the full AOD content. This allows for a significant speed up of the processing time. This paper will discuss the different analysis w...

  10. Using TAGs to Speed up the ATLAS Analysis Process

    CERN Document Server

    Ehrenfeld, W; The ATLAS collaboration

    2010-01-01

    In the ATLAS experiment, Tag Data, or short TAG, are event-level metadata -- thumbnail information about events to support efficient identification and selection of events of interest to a given analysis. TAG quantities range from detector status and trigger information to basic physics quantities, e. g. the number of loose electrons candidates and kinematic information for a limited number of these candidates sorted by their transverse momentum. The average TAG size per event is around 1kB, which is a factor 100 smaller than the Analysis Object Data (AOD) used for physics analysis. TAGs are primarily produced from AODs and stored in ROOT files. For easier access and usability TAGs are also stored in a database. Queries to the database can produce again TAG files. In a standard ATLAS analysis job, TAGs can be used to preselect events based on the TAG quantities before accessing the full AOD content. This allows for s significant speed up of the processing time. This paper will discuss the different analysis w...

  11. The GORE(®) TAG(®) thoracic endoprosthesis.

    Science.gov (United States)

    Vallabhaneni, Raghuveer; Farber, Mark A

    2013-03-01

    The GORE(®) TAG(®) (W.L. Gore and Associates, Inc., [AZ, USA]) has gone through many changes since it was first introduced in the late 1990s. The Conformable GORE TAG has recently become commercially available and underwent several changes from the original design to help increase compression resistance, expand treatment ranges and oversizing windows, and improve conformability. This article describes the GORE TAG and Conformable GORE TAG devices, their potential uses and the outcomes in treating various aortic pathologies.

  12. Versatile protein tagging in cells with split fluorescent protein

    OpenAIRE

    Kamiyama, Daichi; Sekine, Sayaka; Barsi-Rhyne, Benjamin; Hu, Jeffrey; Chen, Baohui; Gilbert, Luke A.; Ishikawa, Hiroaki; Leonetti, Manuel D.; Marshall, Wallace F.; Weissman, Jonathan S.; Huang, Bo

    2016-01-01

    In addition to the popular method of fluorescent protein fusion, live cell protein imaging has now seen more and more application of epitope tags. The small size of these tags may reduce functional perturbation and enable signal amplification. To address their background issue, we adapt self-complementing split fluorescent proteins as epitope tags for live cell protein labelling. The two tags, GFP11 and sfCherry11 are derived from the eleventh β-strand of super-folder GFP and sfCherry, respec...

  13. Selecting additional tag SNPs for tolerating missing data in genotyping

    Directory of Open Access Journals (Sweden)

    Chen Ting

    2005-11-01

    Full Text Available Abstract Background Recent studies have shown that the patterns of linkage disequilibrium observed in human populations have a block-like structure, and a small subset of SNPs (called tag SNPs is sufficient to distinguish each pair of haplotype patterns in the block. In reality, some tag SNPs may be missing, and we may fail to distinguish two distinct haplotypes due to the ambiguity caused by missing data. Results We show there exists a subset of SNPs (referred to as robust tag SNPs which can still distinguish all distinct haplotypes even when some SNPs are missing. The problem of finding minimum robust tag SNPs is shown to be NP-hard. To find robust tag SNPs efficiently, we propose two greedy algorithms and one linear programming relaxation algorithm. The experimental results indicate that (1 the solutions found by these algorithms are quite close to the optimal solution; (2 the genotyping cost saved by using tag SNPs can be as high as 80%; and (3 genotyping additional tag SNPs for tolerating missing data is still cost-effective. Conclusion Genotyping robust tag SNPs is more practical than just genotyping the minimum tag SNPs if we can not avoid the occurrence of missing data. Our theoretical analysis and experimental results show that the performance of our algorithms is not only efficient but the solution found is also close to the optimal solution.

  14. A model-based approach to selection of tag SNPs

    Directory of Open Access Journals (Sweden)

    Sun Fengzhu

    2006-06-01

    Full Text Available Abstract Background Single Nucleotide Polymorphisms (SNPs are the most common type of polymorphisms found in the human genome. Effective genetic association studies require the identification of sets of tag SNPs that capture as much haplotype information as possible. Tag SNP selection is analogous to the problem of data compression in information theory. According to Shannon's framework, the optimal tag set maximizes the entropy of the tag SNPs subject to constraints on the number of SNPs. This approach requires an appropriate probabilistic model. Compared to simple measures of Linkage Disequilibrium (LD, a good model of haplotype sequences can more accurately account for LD structure. It also provides a machinery for the prediction of tagged SNPs and thereby to assess the performances of tag sets through their ability to predict larger SNP sets. Results Here, we compute the description code-lengths of SNP data for an array of models and we develop tag SNP selection methods based on these models and the strategy of entropy maximization. Using data sets from the HapMap and ENCODE projects, we show that the hidden Markov model introduced by Li and Stephens outperforms the other models in several aspects: description code-length of SNP data, information content of tag sets, and prediction of tagged SNPs. This is the first use of this model in the context of tag SNP selection. Conclusion Our study provides strong evidence that the tag sets selected by our best method, based on Li and Stephens model, outperform those chosen by several existing methods. The results also suggest that information content evaluated with a good model is more sensitive for assessing the quality of a tagging set than the correct prediction rate of tagged SNPs. Besides, we show that haplotype phase uncertainty has an almost negligible impact on the ability of good tag sets to predict tagged SNPs. This justifies the selection of tag SNPs on the basis of haplotype

  15. Gene expression analysis of pancreatic cystic neoplasm in SV40Tag transgenic mice model

    Institute of Scientific and Technical Information of China (English)

    Jie Feng; Qiang Sun; Cheng Gao; Juan Dong; Xiao-Luan Wei; Hua Xing; Hou-Da Li

    2007-01-01

    AIM: To study the gene expression changes in pancreatic cystic neoplasm in SV40Tag transgenic mice model and to provide information about the prevention,clinical diagnosis and therapy of pancreatic cancer.METHODS: Using the pBC-SV40Tag transgenic mice model of pancreatic cystic neoplasm, we studied the gene expression changes by applying high-density microarrays. Validation of part gene expression profiling data was performed using real-time PCR.RESULTS: By using high-density oligonucleotide microarray, of 14113 genes, 453 were increased and 760 decreased in pancreatic cystic neoplasm, including oncogenes, cell-cycle-related genes, signal transduction-related genes, skeleton-related genes and metabolism-related genes. Among these, we confirmed the changes in Igf, Shh and Wnt signal pathways with real-time PCR.The results of real-time PCR showed similar expression changes in gene chip.CONCLUSION: all the altered expression genes are associated with cell cycle, DNA damage and repair, signal pathway, and metabolism. SV40Tag may cooperate with several proteins in promoting tumorigenesis.

  16. A novel graded density impactor

    Science.gov (United States)

    Winter, R. E.; Cotton, M.; Harris, E. J.; Chapman, D. J.; Eakins, D.

    2014-05-01

    Ramp loading using graded-density-impactors as flyers in gas-gun-driven plate impact experiments can yield new and useful information about the equation of state and the strength properties of the loaded material. Selective Laser Melting, an additive manufacture technique, was used to manufacture a graded density flyer, termed the "bed of nails" (BON). A 2 mm thick × 100 mm diameter solid disc of stainless steel formed a base for an array of tapered spikes of length 6 mm and spaced 1 mm apart. The two experiments to test the concept were performed at impact velocities of 900 m/s and 1100 m/s using the 100 mm gas gun at the Institute of Shock Physics at Imperial College, London. In each experiment a BON flyer was impacted onto a copper buffer plate which helped to smooth out perturbations in the wave profile. The ramp delivered to the copper buffer was in turn transmitted to three tantalum targets of thicknesses 3, 5 and 7 mm, which were mounted in contact with the back face of the copper. Heterodyne velocimetry was used to measure the velocity-time history, at the back faces of the tantalum discs. The wave profiles display a smooth increase in velocity over a period of ~2.5 us, with no indication of a shock jump. The measured profiles have been analysed to generate a stress strain curve for tantalum. The results have been compared with the predictions of the Sandia National Laboratories hydrocode, CTH.

  17. An Updated Measurement Of Sin 2beta With Multiple Flavor Tags Using A Tag-combining Algorithm

    CERN Document Server

    Gao, T

    2002-01-01

    This thesis reports an updated measurement of Standard Model CP violation parameter sin 2β using the CDF detector at Fermilab. The signal samples of B0/B¯ 0 → J/ψKS and B0/B¯0 → ψ(2 S)KS are extracted from the 110 pb −1 of p- p¯ collisions at s = 1.8 TeV. The flavor of the neutral B mesons is identified at the time of production by three tagging algorithms: a same-side tag, a soft-lepton tag, and an opposite-side- jet tag. The opposite-side-jet tag is a combination of the previously used jet-charge tag and a few new tags. A generic algorithm is developed to combine the tags to improve the tagging performance. A maximum likelihood fitting method is used to determine sin 2β = 0.91+0.37-0.36 . The uncertainties are improved over the previous CDF measurement. The value is consistent with the standard model prediction of a large positive CP asymmetry in this decay mode. It is also consistent with the world average valu...

  18. An updated measurement of sin 2beta with multiple flavor tags using a tag-combining algorithm

    Science.gov (United States)

    Gao, Tianjie

    This thesis reports an updated measurement of Standard Model CP violation parameter sin 2beta using the CDF detector at Fermilab. The signal samples of B0/B¯ 0 → J/psiKS and B0/B¯0 → psi(2 S)KS are extracted from the 110 pb -1 of p-p¯ collisions at s = 1.8 TeV. The flavor of the neutral B mesons is identified at the time of production by three tagging algorithms: a same-side tag, a soft-lepton tag, and an opposite-side-jet tag. The opposite-side-jet tag is a combination of the previously used jet-charge tag and a few new tags. A generic algorithm is developed to combine the tags to improve the tagging performance. A maximum likelihood fitting method is used to determine sin 2beta = 0.91+0.37-0.36 . The uncertainties are improved over the previous CDF measurement. The value is consistent with the standard model prediction of a large positive CP asymmetry in this decay mode. It is also consistent with the world average value of sin 2beta.

  19. Power Electronics Design of a Solar Powered In-car Wireless Tag for Asset Tracking and Parking Applications

    Science.gov (United States)

    Zhu, D.; Henaut, J.; Beeby, S. P.

    2014-11-01

    This paper reports the design and testing of a power conditioning circuit for a solar powered in-car wireless tag for asset tracking and parking application. Existing long range asset tracking is based on the GSM/GPRS network, which requires expensive subscriptions. The EU FP7 project CEWITT aims at developing a credit card sized autonomous wireless tag with GNSS geo-positioning capabilities to ensure the integrity and cost effectiveness for parking applications. It was found in previous research that solar cells are the most suitable energy sources for this application. This study focused on the power electronics design for the wireless tag. A suitable solar cell was chosen for its high power density. Charging circuit, hysteresis control circuit and LDO were designed and integrated to meet the system requirement. Test results showed that charging efficiency of 80 % had been achieved.

  20. [Archival tags and geolocation methods for marine animals: A review].

    Science.gov (United States)

    Zhang, Tian-feng; Fan, Wei; Dai, Yang

    2015-11-01

    Archival tags, a group of data storable electronic tags, are widely used as strong tools for obtaining long term and large scale activity information of marine animals, specifically highly migratory oceanic fishes, and corresponding environmental data. Though retrieving tags is an indispensable step for obtaining data, which is a shortage of archival tags, a series of achievements have been made on marine animals by using archival tags since the 1990s. With the appearance of pop-up satellite tag, which solved the problem of data retrieving and was fully independent of the fishing, both breadth and depth of marine animals' studies are extended by the end of the 1990s. Geolocation based on light intensity is the key to estimate marine animals' movement and has achieved some progress in the past 20 years. However, the accuracy of geolocation for latitude is not high enough, and there is still much room for improvement. To date, most geolocation methods that use ambient daylight involve identifying the times when the sun is at a precisely known zenith angle (e.g., sunrise and sunset). The problem of estimating longitude has been proved easy to solve, but accurate latitude estimates remain elusive. This paper mainly introduced two tags, i. e., archival tags and pop-up tags, and three geolocation methods, i.e. , 1) the "fixed reference" method, 2) the "variable reference" method, and 3) the "reflection" method. We also presented a prospect analysis on archival tags and possible research direction of geolocation methods. We believed that miniaturization and multi-sensor integration are the trends for electronic tags while more environmental factors such as depth, SST (sea surface temperature) or magnetic field intensity, instead of single factor, as auxiliary parameters would be used for improving the geolocation accuracy in the future.

  1. Boosted W/Z Tagging at ATLAS

    CERN Document Server

    Dattagupta, Aparajita; The ATLAS collaboration

    2016-01-01

    A detailed study of the techniques for identifying boosted hadronically decaying W or Z bosons is presented. The best performing algorithm for reconstructing, grooming and tagging bosonic jets as seen in studies using 8 TeV data and simulation is validated for W bosons with a wide range of transverse momenta using 13 TeV data and MC simulations. The same is studied for Z bosons in 13 TeV MC simulation. Improvement in tagger performance using detector tracking information is also studied. In addition, given that a hadronic jet has been identified as resulting from the hadronic decay of a W or Z, a technique is developed to discriminate between W and Z bosons using 8 TeV data. The alternative of using variable-R jets for capturing the hadronic decay products compared to standard techniques is also discussed.

  2. GALAH Survey: Chemically Tagging the Thick Disk

    CERN Document Server

    Bland-Hawthorn, J; Freeman, K

    2015-01-01

    The GALAH survey targets one million stars in the southern hemisphere down to a limiting magnitude of V = 14 at the Anglo- Australian Telescope. The project aims to measure up to 30 elemental abundances and radial velocities (~1 km/s accuracy) for each star at a resolution of R = 28000. These elements fall into 8 independent groups (e.g. alpha, Fe peak, r-process). For all stars, Gaia will provide distances to 1% and transverse velocities to 1 km/s or better, giving us a 14D set of parameters for each star, i.e. 6D phase space and 8D abundance space. There are many scientic applications but here we focus on the prospect of chemically tagging the thick disk and making a direct measurement of how stellar migration evolves with cosmic time.

  3. Reliable Food Traceability Using RFID Tagging

    Science.gov (United States)

    Azuara, Guillermo; Salazar, José L.; Tornos, José L.; Piles, Joan J.

    Radio Frequency IDentification (RFID) technology has numerous potential applications in various industries. One important use is for complete traceability of a specific product with the added advantage of being able to verify that quality controls have been passed, with all the necessary steps complied with and for the time required. The aim of this work is to present a food traceability system using RFID tags with contents guaranteed secure by the use of public-key cryptography and at an affordable cost without the need for substantial investment in infrastructure. Aggregate signatures are used so that all the steps can be signed in a reduced memory space. This type of signature is a cryptographic primitive that "consolidates" several signatures into one in such a way that if n users sign n messages, all the signatures can be grouped into one single signature.

  4. Reconciling Knowledge in Social Tagging Web Services

    Science.gov (United States)

    Aranda-Corral, Gonzalo A.; Borrego-Díaz, Joaquín

    Sometimes we want to search for new information about topics but we can not find relevant results using our own knowledge (for example, our personal bookmarks). A potential solution could be the use of knowledge from other users to find what we are searching for. This solution implies that we can achieve some agreement on implicit semantics used by the other users. We call it Reconciliation of Knowledge. The aim of this paper is to show an agent-based method which lets us reconcile two different knowledge basis (associated with tagging systems) into a common language, obtaining a new one that allows the reconcilitiation of (part of) this knowledge. The agents use Formal Concept Analysis concepts and tools and it has been implemented on the JADE multiagent platform.

  5. Prospecting for chemical tags among open clusters

    CERN Document Server

    Lambert, David L

    2016-01-01

    Determinations of the chemical composition of red giants in a large sample of open clusters show that the abundances of the heavy elements La, Ce, Nd and Sm but not so obviously Y and Eu vary from one cluster to another across a sample all having about the solar metallicity. For La, Ce, Nd and Sm the amplitudes of the variations at solar metallicity scale approximately with the main s-process contribution to solar system material. Consideration of published abundances of field stars suggest that such a spread in heavy element abundances is present for the thin and thick disk stars of different metallicity. This new result provides an opportunity to chemically tag stars by their heavy elements and to reconstruct dissolved open clusters from the field star population.

  6. RFID Torque Sensing Tag System for Fasteners

    Science.gov (United States)

    Fink, Patrick W. (Inventor); Lin, Gregory Y. (Inventor); Ngo, Phong H. (Inventor); Kennedy, Timothy F. (Inventor)

    2016-01-01

    The present invention provides an RFID-based torque sensor that can be used to quickly monitor off the shelf fasteners including fasteners that are used in expensive satellites or other uses where fastener failure can be very costly. In one embodiment, an antenna, RFID ring and spring comprise a sensor tag that can be interrogated with an interrogation signal produced by an interrogator device. When sufficient torque is applied to the fastener, an RFID circuit is connected, and produces a radio frequency (RF) signal that can be read by the interrogator. In one embodiment, the RFID circuit does not transmit when the spring member is not compressed, thereby indicating insufficient tensioning of the fastener. The present invention offers the ability to remotely, quickly, and inexpensively verify that any number of fasteners are torqued properly upon initial installation. Where applicable, the present invention allows low cost monitoring over the life of the fastener.

  7. Korean to English Translation Using Synchronous TAGs

    CERN Document Server

    Egedi, D; Park, H S; Joshi, A K; Egedi, Dania; Palmer, Martha; Park, Hyun S.; Joshi, Aravind K.

    1994-01-01

    It is often argued that accurate machine translation requires reference to contextual knowledge for the correct treatment of linguistic phenomena such as dropped arguments and accurate lexical selection. One of the historical arguments in favor of the interlingua approach has been that, since it revolves around a deep semantic representation, it is better able to handle the types of linguistic phenomena that are seen as requiring a knowledge-based approach. In this paper we present an alternative approach, exemplified by a prototype system for machine translation of English and Korean which is implemented in Synchronous TAGs. This approach is essentially transfer based, and uses semantic feature unification for accurate lexical selection of polysemous verbs. The same semantic features, when combined with a discourse model which stores previously mentioned entities, can also be used for the recovery of topicalized arguments. In this paper we concentrate on the translation of Korean to English.

  8. The loss rates of web tags applied to day-old Anas and Aythya ducklings

    Science.gov (United States)

    Blums, P.; Mednis, A.; Bauga, I.; Nichols, J.D.; Hines, J.E.

    1997-01-01

    Researchers studied the loss rate of web tags on Anas and Aythya ducklings by double marking day-old ducklings of five species with web tags and plasticine-filled rings. Tag loss was examined over three-month, one-year, and three-year periods. Web tag loss was greatest for Anas and occurred mostly in the first three months following tagging.

  9. TagGD: fast and accurate software for DNA Tag generation and demultiplexing.

    Directory of Open Access Journals (Sweden)

    Paul Igor Costea

    Full Text Available Multiplexing is of vital importance for utilizing the full potential of next generation sequencing technologies. We here report TagGD (DNA-based Tag Generator and Demultiplexor, a fully-customisable, fast and accurate software package that can generate thousands of barcodes satisfying user-defined constraints and can guarantee full demultiplexing accuracy. The barcodes are designed to minimise their interference with the experiment. Insertion, deletion and substitution events are considered when designing and demultiplexing barcodes. 20,000 barcodes of length 18 were designed in 5 minutes and 2 million barcoded Illumina HiSeq-like reads generated with an error rate of 2% were demultiplexed with full accuracy in 5 minutes. We believe that our software meets a central demand in the current high-throughput biology and can be utilised in any field with ample sample abundance. The software is available on GitHub (https://github.com/pelinakan/UBD.git.

  10. On the local acceleration and flow trajectory of jet flows from circular and semi-circular pipes via 3D particle tracking velocimetry

    Science.gov (United States)

    Kim, Jin-Tae; Liberzon, Alex; Chamorro, Leonardo P.

    2015-11-01

    The distinctive differences between two jet flows that share the same hydraulic diameter dh = 0.01 m and Re ~ 6000, but different (nozzle) shape are explored via 3D Particle Tracking Velocimetry using OpenPTV (http://www.openptv.net). The two jets are formed from circular and semicircular pipes and released in a quiescent water tank of 40 dh height, 40 dh wide, and 200 dh long. The recirculating system is seeded with 100 μm particles, where flow measurements are performed in the intermediate flow field (14.5 < x /dh <18.5) at 550Hz for a total of ~ 30,000 frames. Analysis is focused on the spatial distribution of the local flow acceleration and curvature of the Lagrangian trajectories. The velocity and acceleration of particles are estimated by low-pass filtering their position with a moving cubic spline fitting, while the curvature is obtained from the Frenet-Serret equations. Probability density functions (p.d.f.) of these quantities are obtained at various sub-volumes containing a given streamwise velocity range, and compared between the two cases to evaluate the memory effects in the intermediate flow field.

  11. Towards Integration of End-User Tags with Professional Annotations

    NARCIS (Netherlands)

    Gligorov, R.; Baltussen, L.B.; Ossenbruggen, J.R. van; Aroyo, L.; Brinkerink, M.; Oomen, J.; Ees, A. van

    2010-01-01

    The goal of the paper is assessing the quality of end-user tags from a video labeling game as a first step in the process of integrating them with the annotations made by professionals. Tags lack precise meaning, whereas the terms and concepts the professionals are used to have a clearly defined sem

  12. Can social tagged images aid concept-based video search?

    NARCIS (Netherlands)

    Setz, A.T.; Snoek, C.G.M.

    2009-01-01

    This paper seeks to unravel whether commonly available social tagged images can be exploited as a training resource for concept-based video search. Since social tags are known to be ambiguous, overly personalized, and often error prone, we place special emphasis on the role of disambiguation. We pre

  13. Tag cloud generation for results of multiple keywords queries

    DEFF Research Database (Denmark)

    2013-01-01

    In this paper we study tag cloud generation for retrieved results of multiple keyword queries. It is motivated by many real world scenarios such as personalization tasks, surveillance systems and information retrieval tasks defined with multiple keywords. We adjust the state-of-the-art tag cloud...

  14. Fully printed flexible and disposable wireless cyclic voltammetry tag.

    Science.gov (United States)

    Jung, Younsu; Park, Hyejin; Park, Jin-Ah; Noh, Jinsoo; Choi, Yunchang; Jung, Minhoon; Jung, Kyunghwan; Pyo, Myungho; Chen, Kevin; Javey, Ali; Cho, Gyoujin

    2015-01-29

    A disposable cyclic voltammetry (CV) tag is printed on a plastic film by integrating wireless power transmitter, polarized triangle wave generator, electrochemical cell and signage through a scalable gravure printing method. By proximity of 13.56 MHz RF reader, the printed CV tag generates 320 mHz of triangular sweep wave from +500 mV to -500 mV which enable to scan a printed electrochemical cell in the CV tag. By simply dropping any specimen solution on the electrochemical cell in the CV tag, the presence of solutes in the solution can be detected and shown on the signage of the CV tag in five sec. 10 mM of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) was used as a standard solute to prove the working concept of fully printed disposable wireless CV tag. Within five seconds, we can wirelessly diagnose the presence of TMPD in the solution using the CV tag in the proximity of the 13.56 MHz RF reader. This fully printed and wirelessly operated flexible CV tag is the first of its kind and marks the path for the utilization of inexpensive and disposable wireless electrochemical sensor systems for initial diagnose hazardous chemicals and biological molecules to improve public hygiene and health.

  15. Social Tagging in a Scholarly Digital Library Environment: Users' Perspectives

    Science.gov (United States)

    Noorhidawati, A.; Hanum, N. Fariza; Zohoorian-Fooladi, N.

    2013-01-01

    Introduction: This paper reports an exploratory study examining how users participate in social tagging activities in a scholarly digital library environment to learn about their motivations, behaviour, and practices. Method: This study was conducted in two phases: a survey to investigate usage and attitudes of social tagging tool, and a…

  16. Folksonomic Tag Clouds as an Aid to Content Indexing

    CERN Document Server

    Harvey, Morgan; Ruthven, Ian; Elsweiler, David

    2009-01-01

    Social tagging systems have recently developed as a popular method of data organisation on the Internet. These systems allow users to organise their content in a way that makes sense to them, rather than forcing them to use a pre-determined and rigid set of categorisations. These folksonomies provide well populated sources of unstructured tags describing web resources which could potentially be used as semantic index terms for these resources. However getting people to agree on what tags best describe a resource is a difficult problem, therefore any feature which increases the consistency and stability of terms chosen would be extremely beneficial. We investigate how the provision of a tag cloud, a weighted list of terms commonly used to assist in browsing a folksonomy, during the tagging process itself influences the tags produced and how difficult the user perceived the task to be. We show that illustrating the most popular tags to users assists in the tagging process and encourages a stable and consistent ...

  17. Versatile protein tagging in cells with split fluorescent protein

    Science.gov (United States)

    Kamiyama, Daichi; Sekine, Sayaka; Barsi-Rhyne, Benjamin; Hu, Jeffrey; Chen, Baohui; Gilbert, Luke A.; Ishikawa, Hiroaki; Leonetti, Manuel D.; Marshall, Wallace F.; Weissman, Jonathan S.; Huang, Bo

    2016-01-01

    In addition to the popular method of fluorescent protein fusion, live cell protein imaging has now seen more and more application of epitope tags. The small size of these tags may reduce functional perturbation and enable signal amplification. To address their background issue, we adapt self-complementing split fluorescent proteins as epitope tags for live cell protein labelling. The two tags, GFP11 and sfCherry11 are derived from the eleventh β-strand of super-folder GFP and sfCherry, respectively. The small size of FP11-tags enables a cost-effective and scalable way to insert them into endogenous genomic loci via CRISPR-mediated homology-directed repair. Tandem arrangement FP11-tags allows proportional enhancement of fluorescence signal in tracking intraflagellar transport particles, or reduction of photobleaching for live microtubule imaging. Finally, we show the utility of tandem GFP11-tag in scaffolding protein oligomerization. These experiments illustrate the versatility of FP11-tag as a labelling tool as well as a multimerization-control tool for both imaging and non-imaging applications. PMID:26988139

  18. Probabilistic Dynamic Framed Slotted ALOHA for RFID Tag Identification

    DEFF Research Database (Denmark)

    Nguyen, Chuyen T.; Hayashi, Kazunori; Kaneko, Megumi

    2013-01-01

    In this paper, we study radio frequency identification tag identification problems using framed slotted ALOHA protocol. Each tag will be assumed to participate in the contention with a certain probability. Then, the frame size and the probability will be dynamically controlled by the reader in ev...

  19. Edible oils from microalgae: insights in TAG accumulation

    NARCIS (Netherlands)

    Klok, A.J.; Lamers, P.P.; Martens, D.E.; Draaisma, R.B.; Wijffels, R.H.

    2014-01-01

    Microalgae are a promising future source for sustainable edible oils. To make microalgal oil a cost-effective alternative for common vegetable oils, increasing TAG productivity and TAG content are of high importance. Fulfilling these targets requires proper understanding of lipid metabolism in

  20. Versatile protein tagging in cells with split fluorescent protein.

    Science.gov (United States)

    Kamiyama, Daichi; Sekine, Sayaka; Barsi-Rhyne, Benjamin; Hu, Jeffrey; Chen, Baohui; Gilbert, Luke A; Ishikawa, Hiroaki; Leonetti, Manuel D; Marshall, Wallace F; Weissman, Jonathan S; Huang, Bo

    2016-03-18

    In addition to the popular method of fluorescent protein fusion, live cell protein imaging has now seen more and more application of epitope tags. The small size of these tags may reduce functional perturbation and enable signal amplification. To address their background issue, we adapt self-complementing split fluorescent proteins as epitope tags for live cell protein labelling. The two tags, GFP11 and sfCherry11 are derived from the eleventh β-strand of super-folder GFP and sfCherry, respectively. The small size of FP11-tags enables a cost-effective and scalable way to insert them into endogenous genomic loci via CRISPR-mediated homology-directed repair. Tandem arrangement FP11-tags allows proportional enhancement of fluorescence signal in tracking intraflagellar transport particles, or reduction of photobleaching for live microtubule imaging. Finally, we show the utility of tandem GFP11-tag in scaffolding protein oligomerization. These experiments illustrate the versatility of FP11-tag as a labelling tool as well as a multimerization-control tool for both imaging and non-imaging applications.