WorldWideScience

Sample records for 3-d multi-lag cross-correlation

  1. Scanning cross-correlator for monitoring uniform 3D ellipsoidal laser beams

    CERN Document Server

    Zelenogorskii, V V; Gacheva, E I; Gelikonov, G V; Krasilnikov, M; Mart'yanov, M A; Mironov, S Yu; Potemkin, A K; Syresin, E M; Stephan, F; Khazanov, E A

    2014-01-01

    The specific features of experimental implementation of a cross-correlator with a scan rate above 1600 cm s(-1) and a spatial delay amplitude of more than 15 mm are considered. The possibility of measuring the width of femtosecond pulses propagating in a train 300 mu s in duration with a repetition rate of 1 MHz is demonstrated. A time resolution of 300 fs for the maximum time window of 50 ps is attained.The cross-correlator is aimed at testing 3D pulses of a laser driver of an electron photo-injector.

  2. Modulated 3D cross-correlation light scattering: Improving turbid sample characterization

    OpenAIRE

    Block, Ian D.; Scheffold, Frank

    2011-01-01

    Accurate characterization using static light scattering (SLS) and dynamic light scattering (DLS) methods mandates the measurement and analysis of singly-scattered light. In turbid samples, the suppression of multiple scattering is therefore required to obtain meaningful results. One powerful technique for achieving this, known as 3D cross-correlation, uses two simultaneous light scattering experiments performed at the same scattering vector on the same sample volume in order to extract only t...

  3. The cross-correlation between 3d cosmic shear and the integrated Sachs-Wolfe effect

    CERN Document Server

    Zieser, Britta

    2016-01-01

    We present the first calculation of the cross-correlation between three-dimensional cosmic shear and the integrated Sachs-Wolfe (iSW) effect. Both signals are combined in a single formalism, which permits the computation of the full covariance matrix. In order to avoid the uncertainties presented by the non-linear evolution of the matter power spectrum and intrinsic alignments of galaxies, our analysis is restricted to large scales, i.e. multipoles below l=1000. We demonstrate in a Fisher analysis that this reduction compared to other studies of three-dimensional weak lensing extending to smaller scales is compensated by the information that is gained if the additional iSW signal and in particular its cross-correlation with lensing data are considered. Given the observational standards of upcoming weak lensing surveys like Euclid, marginal errors on cosmological parameters decrease by ten per cent compared to a cosmic shear experiment if both types of information are combined without a CMB prior. Once the con...

  4. Cross-correlative 3D micro-structural investigation of human bone processed into bone allografts.

    Science.gov (United States)

    Singh, Atul Kumar; Gajiwala, Astrid Lobo; Rai, Ratan Kumar; Khan, Mohd Parvez; Singh, Chandan; Barbhuyan, Tarun; Vijayalakshmi, S; Chattopadhyay, Naibedya; Sinha, Neeraj; Kumar, Ashutosh; Bellare, Jayesh R

    2016-05-01

    Bone allografts (BA) are a cost-effective and sustainable alternative in orthopedic practice as they provide a permanent solution for preserving skeletal architecture and function. Such BA however, must be processed to be disease free and immunologically safe as well as biologically and clinically useful. Here, we have demonstrated a processing protocol for bone allografts and investigated the micro-structural properties of bone collected from osteoporotic and normal human donor samples. In order to characterize BA at different microscopic levels, a combination of techniques such as Solid State Nuclear Magnetic Resonance (ssNMR), Scanning Electron Microscope (SEM), micro-computed tomography (μCT) and Thermal Gravimetric Analysis (TGA) were used for delineating the ultra-structural property of bone. ssNMR revealed the extent of water, collagen fine structure and crystalline order in the bone. These were greatly perturbed in the bone taken from osteoporotic bone donor. Among the processing methods analyzed, pasteurization at 60 °C and radiation treatment appeared to substantially alter the bone integrity. SEM study showed a reduction in Ca/P ratio and non-uniform distribution of elements in osteoporotic bones. μ-CT and MIMICS (Materialize Interactive Medical Image Control System) demonstrated that pasteurization and radiation treatment affects the BA morphology and cause a shift in the HU unit. However, the combination of all these processes restored all-important parameters that are critical for BA integrity and sustainability. Cross-correlation between the various probes we used quantitatively demonstrated differences in morphological and micro-structural properties between BA taken from normal and osteoporotic human donor. Such details could also be instrumental in designing an appropriate bone scaffold. For the best restoration of bone microstructure and to be used as a biomaterial allograft, a step-wise processing method is recommended that preserves all

  5. Cross-correlative 3D micro-structural investigation of human bone processed into bone allografts.

    Science.gov (United States)

    Singh, Atul Kumar; Gajiwala, Astrid Lobo; Rai, Ratan Kumar; Khan, Mohd Parvez; Singh, Chandan; Barbhuyan, Tarun; Vijayalakshmi, S; Chattopadhyay, Naibedya; Sinha, Neeraj; Kumar, Ashutosh; Bellare, Jayesh R

    2016-05-01

    Bone allografts (BA) are a cost-effective and sustainable alternative in orthopedic practice as they provide a permanent solution for preserving skeletal architecture and function. Such BA however, must be processed to be disease free and immunologically safe as well as biologically and clinically useful. Here, we have demonstrated a processing protocol for bone allografts and investigated the micro-structural properties of bone collected from osteoporotic and normal human donor samples. In order to characterize BA at different microscopic levels, a combination of techniques such as Solid State Nuclear Magnetic Resonance (ssNMR), Scanning Electron Microscope (SEM), micro-computed tomography (μCT) and Thermal Gravimetric Analysis (TGA) were used for delineating the ultra-structural property of bone. ssNMR revealed the extent of water, collagen fine structure and crystalline order in the bone. These were greatly perturbed in the bone taken from osteoporotic bone donor. Among the processing methods analyzed, pasteurization at 60 °C and radiation treatment appeared to substantially alter the bone integrity. SEM study showed a reduction in Ca/P ratio and non-uniform distribution of elements in osteoporotic bones. μ-CT and MIMICS (Materialize Interactive Medical Image Control System) demonstrated that pasteurization and radiation treatment affects the BA morphology and cause a shift in the HU unit. However, the combination of all these processes restored all-important parameters that are critical for BA integrity and sustainability. Cross-correlation between the various probes we used quantitatively demonstrated differences in morphological and micro-structural properties between BA taken from normal and osteoporotic human donor. Such details could also be instrumental in designing an appropriate bone scaffold. For the best restoration of bone microstructure and to be used as a biomaterial allograft, a step-wise processing method is recommended that preserves all

  6. Fully automated prostate segmentation in 3D MR based on normalized gradient fields cross-correlation initialization and LOGISMOS refinement

    Science.gov (United States)

    Yin, Yin; Fotin, Sergei V.; Periaswamy, Senthil; Kunz, Justin; Haldankar, Hrishikesh; Muradyan, Naira; Cornud, François; Turkbey, Baris; Choyke, Peter

    2012-02-01

    Manual delineation of the prostate is a challenging task for a clinician due to its complex and irregular shape. Furthermore, the need for precisely targeting the prostate boundary continues to grow. Planning for radiation therapy, MR-ultrasound fusion for image-guided biopsy, multi-parametric MRI tissue characterization, and context-based organ retrieval are examples where accurate prostate delineation can play a critical role in a successful patient outcome. Therefore, a robust automated full prostate segmentation system is desired. In this paper, we present an automated prostate segmentation system for 3D MR images. In this system, the prostate is segmented in two steps: the prostate displacement and size are first detected, and then the boundary is refined by a shape model. The detection approach is based on normalized gradient fields cross-correlation. This approach is fast, robust to intensity variation and provides good accuracy to initialize a prostate mean shape model. The refinement model is based on a graph-search based framework, which contains both shape and topology information during deformation. We generated the graph cost using trained classifiers and used coarse-to-fine search and region-specific classifier training. The proposed algorithm was developed using 261 training images and tested on another 290 cases. The segmentation performance using mean DSC ranging from 0.89 to 0.91 depending on the evaluation subset demonstrates state of the art performance. Running time for the system is about 20 to 40 seconds depending on image size and resolution.

  7. Relocations and 3-D Velocity Structure for Aftershocks of the 2000 W. Tottori (Japan) Earthquake and 2001 Gujarat (India) Earthquake, Using Waveform Cross-correlations

    Science.gov (United States)

    Enescu, B.; Mori, J.

    2004-12-01

    The newly developed double-difference tomography method (Zhang and Thurber,2003) makes use of both absolute and relative arrival times to produce an improved velocity model and highly accurate hypocenter locations. By using this technique, we relocate the aftershocks of the 2000 Western Tottori earthquake (Mw 6.7) and 2001 Gujarat (Mw 7.7) earthquake and obtain a 3D-velocity model of the aftershock region. The first data set consists of 1035 aftershocks recorded at 62 stations during a period of about a month following the mainshock (Shibutani et al.,2002). In order to get the best arrival times a cross-correlation analysis was used to align the waveforms. The epicentral distribution of the relocated events reveals clear earthquake lineations, some of them close to the mainshock, and an increased clustering. The aftershocks' depth distribution shows a mean shift of the hypocenters' centroid of about 580m; a clear upper cutoff of the seismic activity and some clustering can be also seen. The final P-wave velocity model shows higher-value anomalies in the vicinity of the mainshock's hypocenter, in good agreement with the results of Shibutani et al.(2004). The second data set consists of about 1300 earthquakes, recorded during one week of observations by a Japanese-Indian research team in the aftershock region of the Gujarat earthquake (Sato et al.,2001). Using the double-difference algorithm and waveform cross-correlations, we were able to identify a more clear alignment of hypocenters that define the mainshock's fault and an area of relatively few aftershocks in the region of the mainshock's hypocenter. Both studies demonstrate that the cross-correlation techniques applied for events with inter-event distances as large as 10km and cross correlation coefficients as low as 50% can produce more accurate locations than those determined from catalog phase data. We are going to discuss briefly the critical role of frequency filtering and of the time window used for cross-correlation

  8. 3-D Shear Wave Velocity Model of Mexico and South US: Bridging Seismic Networks with Ambient Noise Cross-Correlations (C1) and Correlation of Coda of Correlations (C3).

    Science.gov (United States)

    Spica, Zack; Perton, Mathieu; Calò, Marco; Legrand, Denis; Córdoba Montiel, Francisco; Iglesias, Arturo

    2016-07-01

    This work presents an innovative strategy to enhance the resolution of surface wave tomography obtained from ambient noise cross-correlation (C1) by bridging asynchronous seismic networks through the correlation of coda of correlations (C3). Rayleigh wave group dispersion curves show consistent results between synchronous and asynchronous stations. Rayleigh wave group travel times are inverted to construct velocity-period maps with unprecedented resolution for a region covering Mexico and the southern United States. The resulting period maps are then used to regionalize dispersion curves in order to obtain local 1-D shear velocity models (VS) of the crust and uppermost mantle in every cell of a grid of 0.4°. The 1-D structures are obtained by iteratively adding layers until reaching a given misfit, and a global tomography model is considered as an input for depths below 150 km. Finally, a high-resolution 3-D VS model is obtained from these inversions. The major structures observed in the 3-D model are in agreement with the tectonic-geodynamic features and with previous regional and local studies. It also offers new insights to understand the present and past tectonic evolution of the region.

  9. 3-D shear wave velocity model of Mexico and South US: bridging seismic networks with ambient noise cross-correlations (C1) and correlation of coda of correlations (C3)

    Science.gov (United States)

    Spica, Zack; Perton, Mathieu; Calò, Marco; Legrand, Denis; Córdoba-Montiel, Francisco; Iglesias, Arturo

    2016-09-01

    This work presents an innovative strategy to enhance the resolution of surface wave tomography obtained from ambient noise cross-correlation (C1) by bridging asynchronous seismic networks through the correlation of coda of correlations (C3). Rayleigh wave group dispersion curves show consistent results between synchronous and asynchronous stations. Rayleigh wave group traveltimes are inverted to construct velocity-period maps with unprecedented resolution for a region covering Mexico and the southern United States. The resulting period maps are then used to regionalize dispersion curves in order to obtain local 1-D shear velocity models (VS) of the crust and uppermost mantle in every cell of a grid of 0.4°. The 1-D structures are obtained by iteratively adding layers until reaching a given misfit, and a global tomography model is considered as an input for depths below 150 km. Finally, a high-resolution 3-D VS model is obtained from these inversions. The major structures observed in the 3-D model are in agreement with the tectonic-geodynamic features and with previous regional and local studies. It also offers new insights to understand the present and past tectonic evolution of the region.

  10. Adaptive Multi-Lag for Synthetic Aperture Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Jensen, Jørgen Arendt

    2014-01-01

    ulti- lag method, which is performed in synthetic aperture vector flow data. Measurements are made on laminar and pulsatile, transverse flow profiles. A 7 MHz linear array is connected to t he SARUS research, and acquisitions are made on a vessel phanto m with recirculating blood mimicking fluid driven......The range of detectable velocities in ultrasound flow imaging is linked to the user selection of pulse repetiti on frequency. Whenever a region with large differences in velo city magnitude is visualized, a trade-off has to be made. This work suggests an adaptive spatio-temporaly independent, m...... by a softwar e controlled pump. A multi-lag velocity estimation is perfor med, and a lag is adaptively selected for every estimation point. Results from the constant flow compared to a true parabolic profile sho w an improvement in relative bias from 76.99% to 0.91% and standard deviation from 13.60% to 1...

  11. Cross-correlation laser scattering.

    OpenAIRE

    Kam, Z; Rigler, R

    1982-01-01

    Cross-correlation between two detectors was applied to analyze laser light-scattering fluctuations. Laser scattering from random concentration fluctuations is spatially coherent over small angular areas that are inversely proportional in size to the dimension of the scattering volume. By cross-correlating scattering intensity fluctuations in different angles, the correlation due to relaxation of concentration fluctuations is practically eliminated, and correlations reflecting changes in the s...

  12. Refined Multifractal Cross-Correlation Analysis

    CERN Document Server

    Oświȩcimka, Paweł; Forczek, Marcin; Jadach, Stanisław; Kwapień, Jarosław

    2013-01-01

    We propose a modified algorithm - Multifractal Cross-Correlation Analysis (MFCCA) - that is able to consistently identify and quantify multifractal cross-correlations between two time series. Our motivation for introducing this algorithm is that the already existing methods like MF-DXA have serious limitations for most of the signals describing complex natural processes. The principal component of the related improvement is proper incorporation of the sign of fluctuations. We present a broad analysis of the model fractal stochastic processes as well as of the real-world signals and show that MFCCA is a robust tool and allows a reliable quantification of the cross-correlative structure of analyzed processes. We, in particular, analyze a relation between the generalized Hurst exponent and the MFCCA parameter $\\lambda_q$. This relation provides information about the character of potential multifractality in cross-correlations of the processes under study and thus enables selective insight into their dynamics. Us...

  13. Sidescan Sonar Image Matching Using Cross Correlation

    DEFF Research Database (Denmark)

    Thisen, Erik; Sørensen, Helge Bjarup Dissing; Stage, Bjarne

    2003-01-01

    viewpoints. This paper presents a novel approach for matching two sidescan sonar images. The method first registers the two images to ground, then uses the cross correlation of the object positions on the seabed to find the correct displacement between the two images. In order to correct any minor...

  14. Cross correlations of the cosmic infrared background

    OpenAIRE

    Zhang, Pengjie

    2003-01-01

    The cosmic infrared background (CIB) is a sensitive measure of the star formation history. But this background is overwhelmed by foregrounds, which bias the CIB mean flux and auto correlation measurement severely. Since dominant foregrounds do not correlate with the large scale structure, the cross correlation of CIB with galaxies is free of such foregrounds and presents as an unbiased measure of the star formation history. This also allows the measurement of CIB based on integrated intensity...

  15. Cross-correlation studies with seismic noise

    CERN Document Server

    Hoffmann, H; Cheng, Y; Blair, D G

    2002-01-01

    Ocean waves interacting in shallow water at the shore generate land waves propagating inland. To study these waves vertical, horizontal and tilt seismic noise were measured simultaneously at one location. Vibration isolators designed for gravitational wave research were used for detection. Cross-correlation between the above components was calculated. We found correlations between all of them. However, only the correlation between horizontal and vertical motions could be addressed to land waves, and other correlations are thought to be due to local rigid body motion of the large building in which the experiments were located.

  16. Non-Stationary Effects and Cross Correlations in Solar Activity

    Science.gov (United States)

    Nefedyev, Yuri; Panischev, Oleg; Demin, Sergey

    2016-07-01

    information about cross correlation dynamics between the signals from separate points of the studied system. The 3D cross correlators and their plain projections allow revealing the periodic laws of solar evolution. Work was supported by grants RFBR 15-02-01638-a and 16-02-00496-a.

  17. X-Ray Cross-Correlation Analysis of Disordered Ensembles of Particles: Potentials and Limitations

    Directory of Open Access Journals (Sweden)

    R. P. Kurta

    2013-01-01

    Full Text Available Angular X-ray cross-correlation analysis (XCCA is an approach to study the structure of disordered systems using the results of X-ray scattering experiments. In this paper we summarize recent theoretical developments related to the Fourier analysis of the cross-correlation functions. Results of our simulations demonstrate the application of XCCA to two- and three-dimensional (2D and 3D disordered ensembles of particles. We show that the structure of a single particle can be recovered using X-ray data collected from a 2D disordered system of identical particles. We also demonstrate that valuable structural information about the local structure of 3D systems, inaccessible from a standard small-angle X-ray scattering experiment, can be resolved using XCCA.

  18. World currency exchange rate cross-correlations

    Science.gov (United States)

    Droå¼dż, S.; Górski, A. Z.; Kwapień, J.

    2007-08-01

    World currency network constitutes one of the most complex structures that is associated with the contemporary civilization. On a way towards quantifying its characteristics we study the cross correlations in changes of the daily foreign exchange rates within the basket of 60 currencies in the period December 1998 May 2005. Such a dynamics turns out to predominantly involve one outstanding eigenvalue of the correlation matrix. The magnitude of this eigenvalue depends however crucially on which currency is used as a base currency for the remaining ones. Most prominent it looks from the perspective of a peripheral currency. This largest eigenvalue is seen to systematically decrease and thus the structure of correlations becomes more heterogeneous, when more significant currencies are used as reference. An extreme case in this later respect is the USD in the period considered. Besides providing further insight into subtle nature of complexity, these observations point to a formal procedure that in general can be used for practical purposes of measuring the relative currencies significance on various time horizons.

  19. Cross correlation for debris flow velocity measurement

    Science.gov (United States)

    Arattano, M.

    2003-04-01

    The velocity of debris-flows cannot be easily measured through the classic techniques employed in hydraulics. In hydraulics velocity measurements are made through the use of current meters, through methods that appeal to the principle of critical flow (weirs, Venturi flumes, Parshall flumes etc.) or that make use of chemical tracers. Debris-flow fronts contain large boulders and their tails, which are certainly more fluid, remain charged with pebble-sized fragments. This impedes the use of current meters, weirs and flumes that would be damaged or destroyed by the passage of the flow. Thus debris flow velocity measurements require the use of remote sensors. A pair of ultrasonic sensors placed at a known distance from each other along the torrent have been used as a method to obtain mean front velocity of debris-flows. Also seismic and acoustic sensors have been employed to measure debris-flow front velocity and discharge in the same manner. However these methods require the presence of a well identifiable and defined main front in the debris flow wave. In fact the time lag between the recordings of the front of the wave at two consecutive stations allows an estimation of its mean velocity. When the front is not present cross correlation may help in identifying the mean velocity of the flow. This has been proved using the field data recorded through seismic and ultrasonic sensors in a small instrumented catchment on the Italian Alps.

  20. Multifractal Detrended Cross-Correlation Analysis of agricultural futures markets

    Energy Technology Data Exchange (ETDEWEB)

    He Lingyun, E-mail: lyhe@amss.ac.cn [Center for Futures and Financial Derivatives, College of Economics and Management, China Agricultural University, Beijing 100083 (China); Chen Shupeng [Center for Futures and Financial Derivatives, College of Economics and Management, China Agricultural University, Beijing 100083 (China)

    2011-06-15

    Highlights: > We investigated cross-correlations between China's and US agricultural futures markets. > Power-law cross-correlations are found between the geographically far but correlated markets. > Multifractal features are significant in all the markets. > Cross-correlation exponent is less than averaged GHE when q < 0 and greater than the latter when q > 0. - Abstract: We investigated geographically far but temporally correlated China's and US agricultural futures markets. We found that there exists a power-law cross-correlation between them, and that multifractal features are significant in all the markets. It is very interesting that the geographically far markets show strong cross-correlations and share much of their multifractal structure. Furthermore, we found that for all the agricultural futures markets in our studies, the cross-correlation exponent is less than the averaged generalized Hurst exponents (GHE) when q < 0 and greater than the averaged GHE when q > 0.

  1. Robust Statistical Detection of Power-Law Cross-Correlation

    Science.gov (United States)

    Blythe, Duncan A. J.; Nikulin, Vadim V.; Müller, Klaus-Robert

    2016-06-01

    We show that widely used approaches in statistical physics incorrectly indicate the existence of power-law cross-correlations between financial stock market fluctuations measured over several years and the neuronal activity of the human brain lasting for only a few minutes. While such cross-correlations are nonsensical, no current methodology allows them to be reliably discarded, leaving researchers at greater risk when the spurious nature of cross-correlations is not clear from the unrelated origin of the time series and rather requires careful statistical estimation. Here we propose a theory and method (PLCC-test) which allows us to rigorously and robustly test for power-law cross-correlations, correctly detecting genuine and discarding spurious cross-correlations, thus establishing meaningful relationships between processes in complex physical systems. Our method reveals for the first time the presence of power-law cross-correlations between amplitudes of the alpha and beta frequency ranges of the human electroencephalogram.

  2. Multifractal cross-correlation spectra analysis on Chinese stock markets

    Science.gov (United States)

    Zhao, Xiaojun; Shang, Pengjian; Shi, Wenbin

    2014-05-01

    In this paper, the long-range cross-correlation of Chinese stock indices is systematically studied. The multifractal detrended cross-correlation analysis (MF-DXA) appears to be one of the most effective methods in detecting long-range cross-correlation of two non-stationary variables. The Legendre spectrum and the large deviations spectrum are extended to the cross-correlation case, so as to present multifractal structure of stock return and volatility series. It is characterized of the multifractality in Chinese stock markets, partly due to clusters of local detrended covariance with large and small magnitudes.

  3. The influence of noise sources on cross-correlation amplitudes

    CERN Document Server

    Hanasoge, Shravan M

    2012-01-01

    We use analytical examples and asymptotic forms to examine the mathematical structure and physical meaning of the seismic cross correlation measurement. We show that in general, cross correlations are not Green's functions of medium, and may be very different depending on the source distribution. The modeling of noise sources using spatial distributions as opposed to discrete collections of sources is emphasized. When stations are illuminated by spatially complex source distributions, cross correlations show arrivals at a variety of time lags, from zero to the maximum surface-wave arrival time. Here, we demonstrate the possibility of inverting for the source distribution using the energy of the full cross-correlation waveform. The interplay between the source distribution and wave attenuation in determining the functional dependence of cross correlation energies on station-pair distance is quantified. Without question, energies contain information about wave attenuation. However, the accurate interpretation o...

  4. 3D Animation Essentials

    CERN Document Server

    Beane, Andy

    2012-01-01

    The essential fundamentals of 3D animation for aspiring 3D artists 3D is everywhere--video games, movie and television special effects, mobile devices, etc. Many aspiring artists and animators have grown up with 3D and computers, and naturally gravitate to this field as their area of interest. Bringing a blend of studio and classroom experience to offer you thorough coverage of the 3D animation industry, this must-have book shows you what it takes to create compelling and realistic 3D imagery. Serves as the first step to understanding the language of 3D and computer graphics (CG)Covers 3D anim

  5. 3D video

    CERN Document Server

    Lucas, Laurent; Loscos, Céline

    2013-01-01

    While 3D vision has existed for many years, the use of 3D cameras and video-based modeling by the film industry has induced an explosion of interest for 3D acquisition technology, 3D content and 3D displays. As such, 3D video has become one of the new technology trends of this century.The chapters in this book cover a large spectrum of areas connected to 3D video, which are presented both theoretically and technologically, while taking into account both physiological and perceptual aspects. Stepping away from traditional 3D vision, the authors, all currently involved in these areas, provide th

  6. Detrended cross-correlation analysis consistently extended to multifractality

    Science.gov (United States)

    Oświȩcimka, Paweł; DroŻdŻ, Stanisław; Forczek, Marcin; Jadach, Stanisław; Kwapień, Jarosław

    2014-02-01

    We propose an algorithm, multifractal cross-correlation analysis (MFCCA), which constitutes a consistent extension of the detrended cross-correlation analysis and is able to properly identify and quantify subtle characteristics of multifractal cross-correlations between two time series. Our motivation for introducing this algorithm is that the already existing methods, like multifractal extension, have at best serious limitations for most of the signals describing complex natural processes and often indicate multifractal cross-correlations when there are none. The principal component of the present extension is proper incorporation of the sign of fluctuations to their generalized moments. Furthermore, we present a broad analysis of the model fractal stochastic processes as well as of the real-world signals and show that MFCCA is a robust and selective tool at the same time and therefore allows for a reliable quantification of the cross-correlative structure of analyzed processes. In particular, it allows one to identify the boundaries of the multifractal scaling and to analyze a relation between the generalized Hurst exponent and the multifractal scaling parameter λq. This relation provides information about the character of potential multifractality in cross-correlations and thus enables a deeper insight into dynamics of the analyzed processes than allowed by any other related method available so far. By using examples of time series from the stock market, we show that financial fluctuations typically cross-correlate multifractally only for relatively large fluctuations, whereas small fluctuations remain mutually independent even at maximum of such cross-correlations. Finally, we indicate possible utility of MFCCA to study effects of the time-lagged cross-correlations.

  7. Reprint of : Cross-correlations of coherent multiple Andreev reflections

    Science.gov (United States)

    Riwar, Roman-Pascal; Badiane, Driss M.; Houzet, Manuel; Meyer, Julia S.; Nazarov, Yuli V.

    2016-08-01

    We use the Landauer-Büttiker scattering theory for electronic transport to calculate the current cross-correlations in a voltage-biased three-terminal junction with all superconducting leads. At low bias voltage, when charge transport is due to coherent multiple Andreev reflections, we find large cross-correlations compared with their normal-state value. Furthermore, depending on the parameters that characterize the properties of the scattering region between the leads, the cross-correlations can reverse their sign with respect to the case of non-interacting fermionic systems.

  8. Intermittency induced long-range cross-correlations

    CERN Document Server

    Diakonos, Fotis K; Schmelcher, Peter

    2013-01-01

    Cross-correlations are usually considered to emerge through interaction between particles. Here we present a mechanism capable to generate power-law cross-correlations between non-interacting particles exposed to an external potential. This phenomenon can occur as an ensemble property when the external potential induces intermittent dynamics, providing laminar and stochastic phases of motion. We have strong indications that the divergence of the mean residence time in the laminar phase of the single particle motion - sporadic dynamics - is a sufficient condition for the emergence of long-range cross-correlations. We argue that this mechanism may be relevant for the occurrence of collective behaviour in critical systems.

  9. F2DPR: a fast and robust cross-correlation technique for volumetric PIV

    Science.gov (United States)

    Earl, Thomas; Jeon, Young Jin; Lecordier, Bertrand; David, Laurent

    2016-08-01

    The current state-of-the-art in cross-correlation based time-resolved particle image velocimetry (PIV) techniques are the fluid trajectory correlation, FTC (Lynch and Scarano 2013) and the fluid trajectory evaluation based on an ensemble-averaged cross-correlation, FTEE (Jeon et al 2014a). These techniques compute the velocity vector as a polynomial trajectory Γ in space and time, enabling the extraction of beneficial quantities such as material acceleration whilst significantly increasing the accuracy of the particle displacement prediction achieved by standard two-frame PIV. In the context of time-resolved volumetric PIV, the drawback of trajectory computation is the computational expense of the three-dimensional (3D) cross-correlation, exacerbated by the requirement to perform N  -  1 cross-correlations, where N (for typically 5≤slant N≤slant 9 ) is the number of sequential particle volumes, for each velocity field. Therefore, the acceleration of this calculation is highly desirable. This paper re-examines the application of two-dimensional (2D) cross-correlation methods to three-dimensional (3D) datasets by Bilsky et al (2011) and the binning techniques of Discetti and Astarita (2012). A new and robust version of the 2D methods is proposed and described, called fast 2D projection—re-projection (f2dpr). Performance tests based on computational time and accuracy for both two-frame and multi-frame PIV are carried out on synthetically generated data. The cases presented herein include uniaxial uniform linear displacements and shear, and simulated turbulence data. The proposed algorithm is shown to be in the order of 10 times faster than a standard 3D FFT without loss of precision for a wide range of synthetic test cases, while combining with the binning technique can yield 50 times faster computation. The algorithm is also applied to reconstructed synthetic turbulent particle fields to investigate reconstruction noise on its performance and no

  10. F2DPR: a fast and robust cross-correlation technique for volumetric PIV

    Science.gov (United States)

    Earl, Thomas; Jeon, Young Jin; Lecordier, Bertrand; David, Laurent

    2016-08-01

    The current state-of-the-art in cross-correlation based time-resolved particle image velocimetry (PIV) techniques are the fluid trajectory correlation, FTC (Lynch and Scarano 2013) and the fluid trajectory evaluation based on an ensemble-averaged cross-correlation, FTEE (Jeon et al 2014a). These techniques compute the velocity vector as a polynomial trajectory Γ in space and time, enabling the extraction of beneficial quantities such as material acceleration whilst significantly increasing the accuracy of the particle displacement prediction achieved by standard two-frame PIV. In the context of time-resolved volumetric PIV, the drawback of trajectory computation is the computational expense of the three-dimensional (3D) cross-correlation, exacerbated by the requirement to perform N  ‑  1 cross-correlations, where N (for typically 5≤slant N≤slant 9 ) is the number of sequential particle volumes, for each velocity field. Therefore, the acceleration of this calculation is highly desirable. This paper re-examines the application of two-dimensional (2D) cross-correlation methods to three-dimensional (3D) datasets by Bilsky et al (2011) and the binning techniques of Discetti and Astarita (2012). A new and robust version of the 2D methods is proposed and described, called fast 2D projection—re-projection (f2dpr). Performance tests based on computational time and accuracy for both two-frame and multi-frame PIV are carried out on synthetically generated data. The cases presented herein include uniaxial uniform linear displacements and shear, and simulated turbulence data. The proposed algorithm is shown to be in the order of 10 times faster than a standard 3D FFT without loss of precision for a wide range of synthetic test cases, while combining with the binning technique can yield 50 times faster computation. The algorithm is also applied to reconstructed synthetic turbulent particle fields to investigate reconstruction noise on its performance and no

  11. Low-power Cross-Correlator ASIC Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Pacific MicroCHIP Corporation offers to design an ASIC that includes a cross-correlation unit together with the interfaces to be connected to the output of the...

  12. Acoustic ship signature measurements by cross-correlation method.

    Science.gov (United States)

    Fillinger, Laurent; Sutin, Alexander; Sedunov, Alexander

    2011-02-01

    Cross-correlation methods were applied for the estimation of the power spectral density and modulation spectrum of underwater noise generated by moving vessels. The cross-correlation of the signal from two hydrophones allows the separation of vessel acoustic signatures in a busy estuary. Experimental data recorded in the Hudson River are used for demonstration that cross-correlation method measured the same ship noise and ship noise modulation spectra as conventional methods. The cross-correlation method was then applied for the separation of the acoustic signatures of two ships present simultaneously. Presented methods can be useful for ship traffic monitoring and small ship classification, even in noisy harbor environments. PMID:21361436

  13. Microscopic realization of cross-correlated noise processes

    OpenAIRE

    Shit, Anindita; Chattopadhyay, Sudip; Banik, Suman Kumar; Chaudhuri, Jyotipratim Ray

    2010-01-01

    We present a microscopic theory of cross-correlated noise processes, starting from a Hamiltonian system-reservoir description. In the proposed model, the system is nonlinearly coupled to a reservoir composed of harmonic oscillators, which in turn is driven by an external fluctuating force. We show that the resultant Langevin equation derived from the composite system (system+reservoir+external modulation) contains the essential features of cross-correlated noise processes.

  14. Microscopic realization of cross-correlated noise processes.

    Science.gov (United States)

    Shit, Anindita; Chattopadhyay, Sudip; Banik, Suman Kumar; Chaudhuri, Jyotipratim Ray

    2010-06-01

    We present a microscopic theory of cross-correlated noise processes, starting from a Hamiltonian system-reservoir description. In the proposed model, the system is nonlinearly coupled to a reservoir composed of harmonic oscillators, which in turn is driven by an external fluctuating force. We show that the resultant Langevin equation derived from the composite system (system+reservoir+external modulation) contains the essential features of cross-correlated noise processes. PMID:20590326

  15. Robust Statistical Detection of Power-Law Cross-Correlation.

    Science.gov (United States)

    Blythe, Duncan A J; Nikulin, Vadim V; Müller, Klaus-Robert

    2016-01-01

    We show that widely used approaches in statistical physics incorrectly indicate the existence of power-law cross-correlations between financial stock market fluctuations measured over several years and the neuronal activity of the human brain lasting for only a few minutes. While such cross-correlations are nonsensical, no current methodology allows them to be reliably discarded, leaving researchers at greater risk when the spurious nature of cross-correlations is not clear from the unrelated origin of the time series and rather requires careful statistical estimation. Here we propose a theory and method (PLCC-test) which allows us to rigorously and robustly test for power-law cross-correlations, correctly detecting genuine and discarding spurious cross-correlations, thus establishing meaningful relationships between processes in complex physical systems. Our method reveals for the first time the presence of power-law cross-correlations between amplitudes of the alpha and beta frequency ranges of the human electroencephalogram. PMID:27250630

  16. Statistical tests for power-law cross-correlated processes

    Science.gov (United States)

    Podobnik, Boris; Jiang, Zhi-Qiang; Zhou, Wei-Xing; Stanley, H. Eugene

    2011-12-01

    For stationary time series, the cross-covariance and the cross-correlation as functions of time lag n serve to quantify the similarity of two time series. The latter measure is also used to assess whether the cross-correlations are statistically significant. For nonstationary time series, the analogous measures are detrended cross-correlations analysis (DCCA) and the recently proposed detrended cross-correlation coefficient, ρDCCA(T,n), where T is the total length of the time series and n the window size. For ρDCCA(T,n), we numerically calculated the Cauchy inequality -1≤ρDCCA(T,n)≤1. Here we derive -1≤ρDCCA(T,n)≤1 for a standard variance-covariance approach and for a detrending approach. For overlapping windows, we find the range of ρDCCA within which the cross-correlations become statistically significant. For overlapping windows we numerically determine—and for nonoverlapping windows we derive—that the standard deviation of ρDCCA(T,n) tends with increasing T to 1/T. Using ρDCCA(T,n) we show that the Chinese financial market's tendency to follow the U.S. market is extremely weak. We also propose an additional statistical test that can be used to quantify the existence of cross-correlations between two power-law correlated time series.

  17. Statistical tests for power-law cross-correlated processes.

    Science.gov (United States)

    Podobnik, Boris; Jiang, Zhi-Qiang; Zhou, Wei-Xing; Stanley, H Eugene

    2011-12-01

    For stationary time series, the cross-covariance and the cross-correlation as functions of time lag n serve to quantify the similarity of two time series. The latter measure is also used to assess whether the cross-correlations are statistically significant. For nonstationary time series, the analogous measures are detrended cross-correlations analysis (DCCA) and the recently proposed detrended cross-correlation coefficient, ρ(DCCA)(T,n), where T is the total length of the time series and n the window size. For ρ(DCCA)(T,n), we numerically calculated the Cauchy inequality -1 ≤ ρ(DCCA)(T,n) ≤ 1. Here we derive -1 ≤ ρ DCCA)(T,n) ≤ 1 for a standard variance-covariance approach and for a detrending approach. For overlapping windows, we find the range of ρ(DCCA) within which the cross-correlations become statistically significant. For overlapping windows we numerically determine-and for nonoverlapping windows we derive--that the standard deviation of ρ(DCCA)(T,n) tends with increasing T to 1/T. Using ρ(DCCA)(T,n) we show that the Chinese financial market's tendency to follow the U.S. market is extremely weak. We also propose an additional statistical test that can be used to quantify the existence of cross-correlations between two power-law correlated time series. PMID:22304166

  18. EUROPEANA AND 3D

    Directory of Open Access Journals (Sweden)

    D. Pletinckx

    2012-09-01

    Full Text Available The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  19. Solid works 3D

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Cheol Yeong

    2004-02-15

    This book explains modeling of solid works 3D and application of 3D CAD/CAM. The contents of this book are outline of modeling such as CAD and 2D and 3D, solid works composition, method of sketch, writing measurement fixing, selecting projection, choosing condition of restriction, practice of sketch, making parts, reforming parts, modeling 3D, revising 3D modeling, using pattern function, modeling necessaries, assembling, floor plan, 3D modeling method, practice floor plans for industrial engineer data aided manufacturing, processing of CAD/CAM interface.

  20. Solid works 3D

    International Nuclear Information System (INIS)

    This book explains modeling of solid works 3D and application of 3D CAD/CAM. The contents of this book are outline of modeling such as CAD and 2D and 3D, solid works composition, method of sketch, writing measurement fixing, selecting projection, choosing condition of restriction, practice of sketch, making parts, reforming parts, modeling 3D, revising 3D modeling, using pattern function, modeling necessaries, assembling, floor plan, 3D modeling method, practice floor plans for industrial engineer data aided manufacturing, processing of CAD/CAM interface.

  1. Cross-correlation of the cosmic 21-cm signal and Lyman α emitters during reionization

    Science.gov (United States)

    Sobacchi, Emanuele; Mesinger, Andrei; Greig, Bradley

    2016-07-01

    Interferometry of the cosmic 21-cm signal is set to revolutionize our understanding of the Epoch of Reionization (EoR), eventually providing 3D maps of the early Universe. Initial detections however will be low signal to noise, limited by systematics. To confirm a putative 21-cm detection, and check the accuracy of 21-cm data analysis pipelines, it would be very useful to cross-correlate against a genuine cosmological signal. The most promising cosmological signals are wide-field maps of Lyman α emitting galaxies (LAEs), expected from the Subaru Hyper-Suprime Cam ultradeep field (UDF). Here we present estimates of the correlation between LAE maps at z ˜ 7 and the 21-cm signal observed by both the Low Frequency Array (LOFAR) and the planned Square Kilometre Array Phase 1 (SKA1). We adopt a systematic approach, varying both: (i) the prescription of assigning LAEs to host haloes; and (ii) the large-scale structure of neutral and ionized regions (i.e. EoR morphology). We find that the LAE-21cm cross-correlation is insensitive to (i), thus making it a robust probe of the EoR. A 1000 h observation with LOFAR would be sufficient to discriminate at ≳ 1σ a fully ionized Universe from one with a mean neutral fraction of bar{x}_{H I}≈ 0.50, using the LAE-21 cm cross-correlation function on scales of R ≈ 3-10 Mpc. Unlike LOFAR, whose detection of the LAE-21 cm cross-correlation is limited by noise, SKA1 is mostly limited by ignorance of the EoR morphology. However, the planned 100 h wide-field SKA1-Low survey will be sufficient to discriminate an ionized Universe from one with bar{x}_{H I}=0.25, even with maximally pessimistic assumptions.

  2. Cross correlation of Cosmic Microwave background and Weak Lensing

    CERN Document Server

    Lee, Seokcheon

    2015-01-01

    The integrated Sachs-Wolfe (ISW) effect and its non-linear extension Rees-Sciama (RS) effect provide us the information of the time evolution of gravitational potential. The cross-correlation between the cosmic microwave background (CMB) and the large scale structure (LSS) is known as a promising way to extract the ISW (RS) effect. It is known that the RS effect shows the unique behavior by changing the anti-correlated cross correlation between the CMB and the mass tracer into the positively correlated cross correlation compared to the linear ISW effect. We show that the dependence of this flipping scale of the cross-correlation between RS and weak lensing on dark energy models. However, there exists the degeneracy between DE and $\\Omega_{\\rm{m}0}$ which might be broken by redshift dependent observables. The cross-correlation between the momentum field and the density field might be served as the better observable to be used for this purpose.

  3. 3d-3d correspondence revisited

    Science.gov (United States)

    Chung, Hee-Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr

    2016-04-01

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d {N}=2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. We also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  4. IZDELAVA TISKALNIKA 3D

    OpenAIRE

    Brdnik, Lovro

    2015-01-01

    Diplomsko delo analizira trenutno stanje 3D tiskalnikov na trgu. Prikazan je razvoj in principi delovanja 3D tiskalnikov. Predstavljeni so tipi 3D tiskalnikov, njihove prednosti in slabosti. Podrobneje je predstavljena zgradba in delovanje koračnih motorjev. Opravljene so meritve koračnih motorjev. Opisana je programska oprema za rokovanje s 3D tiskalniki in komponente, ki jih potrebujemo za izdelavo. Diploma se oklepa vprašanja, ali je izdelava 3D tiskalnika bolj ekonomična kot pa naložba v ...

  5. 3D and Education

    Science.gov (United States)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

  6. Audio Quality Assurance : An Application of Cross Correlation

    DEFF Research Database (Denmark)

    Jurik, Bolette Ammitzbøll; Nielsen, Jesper Asbjørn Sindahl

    2012-01-01

    We describe algorithms for automated quality assurance on content of audio files in context of preservation actions and access. The algorithms use cross correlation to compare the sound waves. They are used to do overlap analysis in an access scenario, where preserved radio broadcasts are used in...

  7. Power-law cross-correlations estimation under heavy tails

    Science.gov (United States)

    Kristoufek, Ladislav

    2016-11-01

    We examine the performance of six estimators of the power-law cross-correlations-the detrended cross-correlation analysis, the detrending moving-average cross-correlation analysis, the height cross-correlation analysis, the averaged periodogram estimator, the cross-periodogram estimator and the local cross-Whittle estimator-under heavy-tailed distributions. The selection of estimators allows to separate these into the time and frequency domain estimators. By varying the characteristic exponent of the α-stable distributions which controls the tails behavior, we report several interesting findings. First, the frequency domain estimators are practically unaffected by heavy tails bias-wise. Second, the time domain estimators are upward biased for heavy tails but they have lower estimator variance than the other group for short series. Third, specific estimators are more appropriate depending on distributional properties and length of the analyzed series. In addition, we provide a discussion of implications of these results for empirical applications as well as theoretical explanations.

  8. Absence of significant cross-correlation between WMAP and SDSS

    CERN Document Server

    Lopez-Corredoira, M; Betancort-Rijo, J

    2010-01-01

    AIMS. Recently, several authors have claimed to detect a significant cross-correlation between microwave WMAP anisotropies and the SDSS galaxy distribution. We repeat these analyses determining different cross-correlation errors: re-sampling errors, and field-to-field fluctuations. The first type of errors make use of overlapping sky regions, while the second type use non-overlapping sky regions. METHODS. For the re-sampling errors we use bootstrap and jack-knife techniques. For the field-to-field fluctuations we use three methods: 1) evaluating the dispersion of the cross-correlation when correlating separated regions of WMAP with the original region of SDSS; 2) using mock Monte Carlo WMAP maps; 3) a new method (developed herein) which gives the error as an integral of the product of the self-correlations of each map. RESULTS. The average cross-correlation for b>30 deg. is significantly larger than the re-sampling errors--both jack-knife and bootstrap give similar results--but it is of the order of the field...

  9. Cross correlation surveys with the Square Kilometre Array

    CERN Document Server

    Kirk, Donnacha; Abdalla, Filipe B; Bull, Philip; Joachimi, Benjamin

    2015-01-01

    By the time that the first phase of the Square Kilometre Array is deployed it will be able to perform state of the art Large Scale Structure (LSS) as well as Weak Gravitational Lensing (WGL) measurements of the distribution of matter in the Universe. In this chapter we concentrate on the synergies that result from cross-correlating these different SKA data products as well as external correlation with the weak lensing measurements available from CMB missions. We show that the Dark Energy figures of merit obtained individually from WGL/LSS measurements and their independent combination is significantly increased when their full cross-correlations are taken into account. This is due to the increased knowledge of galaxy bias as a function of redshift as well as the extra information from the different cosmological dependences of the cross-correlations. We show that the cross-correlation between a spectroscopic LSS sample and a weak lensing sample with photometric redshifts can calibrate these same photometric re...

  10. 3D super-virtual refraction interferometry

    KAUST Repository

    Lu, Kai

    2014-08-05

    Super-virtual refraction interferometry enhances the signal-to-noise ratio of far-offset refractions. However, when applied to 3D cases, traditional 2D SVI suffers because the stationary positions of the source-receiver pairs might be any place along the recording plane, not just along a receiver line. Moreover, the effect of enhancing the SNR can be limited because of the limitations in the number of survey lines, irregular line geometries, and azimuthal range of arrivals. We have developed a 3D SVI method to overcome these problems. By integrating along the source or receiver lines, the cross-correlation or the convolution result of a trace pair with the source or receiver at the stationary position can be calculated without the requirement of knowing the stationary locations. In addition, the amplitudes of the cross-correlation and convolution results are largely strengthened by integration, which is helpful to further enhance the SNR. In this paper, both synthetic and field data examples are presented, demonstrating that the super-virtual refractions generated by our method have accurate traveltimes and much improved SNR.

  11. 3D virtuel udstilling

    DEFF Research Database (Denmark)

    Tournay, Bruno; Rüdiger, Bjarne

    2006-01-01

    3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s.......3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s....

  12. Blender 3D cookbook

    CERN Document Server

    Valenza, Enrico

    2015-01-01

    This book is aimed at the professionals that already have good 3D CGI experience with commercial packages and have now decided to try the open source Blender and want to experiment with something more complex than the average tutorials on the web. However, it's also aimed at the intermediate Blender users who simply want to go some steps further.It's taken for granted that you already know how to move inside the Blender interface, that you already have 3D modeling knowledge, and also that of basic 3D modeling and rendering concepts, for example, edge-loops, n-gons, or samples. In any case, it'

  13. NIRS-BASED CORTICAL ACTIVATION ANALYSIS BY TEMPORAL CROSS CORRELATION

    Directory of Open Access Journals (Sweden)

    Raul Fernandez-Rojas

    2016-02-01

    Full Text Available In this study we present a method of signal processing to determine dominant channels in near infrared spectroscopy (NIRS. To compare measuring channels and identify delays between them, cross correlation is computed. Furthermore, to find out possible dominant channels, a visual inspection was performed. The outcomes demonstrated that the visual inspection exhibited evoked-related activations in the primary somatosensory cortex (S1 after stimulation which is consistent with comparable studies and the cross correlation study discovered dominant channels on both cerebral hemispheres. The analysis also showed a relationship between dominant channels and adjacent channels. For that reason, our results present a new method to identify dominant regions in the cerebral cortex using near-infrared spectroscopy. These findings have also implications in the decrease of channels by eliminating irrelevant channels for the experiment.

  14. The Atacama Cosmology Telescope: Cross Correlation with Planck maps

    CERN Document Server

    Louis, Thibaut; Hasselfield, Matthew; Bond, J Richard; Calabrese, Erminia; Das, Sudeep; Devlin, Mark J; Dunkley, Joanna; Dünner, Rolando; Gralla, Megan; Hajian, Amir; Hincks, Adam D; Hlozek, Renée; Huffenberger, Kevin; Infante, Leopoldo; Kosowsky, Arthur; Marriage, Tobias A; Moodley, Kavilan; Næss, Sigurd; Niemack, Michael D; Nolta, Michael R; Page, Lyman A; Partridge, Bruce; Sehgal, Neelima; Sievers, Jonathan L; Spergel, David N; Staggs, Suzanne T; Walter, Benjamin Z; Wollack, Edward J

    2014-01-01

    We present the temperature power spectrum of the Cosmic Microwave Background obtained by cross-correlating maps from the Atacama Cosmology Telescope (ACT) at 148 and 218 GHz with maps from the Planck satellite at 143 and 217 GHz, in two overlapping regions covering 592 square degrees. We find excellent agreement between the two datasets at both frequencies, quantified using the variance of the residuals between the ACT power spectra and the ACTxPlanck cross-spectra. We use these cross-correlations to calibrate the ACT data at 148 and 218 GHz, to 0.7% and 2% precision respectively. We find no evidence for anisotropy in the calibration parameter. We compare the Planck 353 GHz power spectrum with the measured amplitudes of dust and cosmic infrared background (CIB) of ACT data at 148 and 218 GHz. We also compare planet and point source measurements from the two experiments.

  15. The Atacama Cosmology Telescope: cross correlation with Planck maps

    Energy Technology Data Exchange (ETDEWEB)

    Louis, Thibaut; Calabrese, Erminia; Dunkley, Joanna; Næss, Sigurd [Department of Astrophysics, Oxford University, Oxford OX1 3RH (United Kingdom); Addison, Graeme E.; Hincks, Adam D. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Hasselfield, Matthew; Hlozek, Renée [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Bond, J. Richard; Hajian, Amir [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Das, Sudeep [Argonne National Laboratory, 9700 S. Cass Ave., Lemont, IL 60439 (United States); Devlin, Mark J. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104, U.S.A (United States); Dünner, Rolando; Infante, Leopoldo [Departamento de Astronomía y Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile); Gralla, Megan; Marriage, Tobias A. [Dept. of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2686 (United States); Huffenberger, Kevin [Department of Physics, Florida State University, Keen Physics Building, 77 Chieftan Way, Tallahassee, Florida (United States); Kosowsky, Arthur [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, 15260 (United States); Moodley, Kavilan [Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, University of KwaZulu-Natal, Durban, 4041 (South Africa); Niemack, Michael D., E-mail: Thibaut.Louis@astro.ox.ac.uk [Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544 (United States); and others

    2014-07-01

    We present the temperature power spectrum of the Cosmic Microwave Background obtained by cross-correlating maps from the Atacama Cosmology Telescope (ACT) at 148 and 218 GHz with maps from the Planck satellite at 143 and 217 GHz, in two overlapping regions covering 592 square degrees. We find excellent agreement between the two datasets at both frequencies, quantified using the variance of the residuals between the ACT power spectra and the ACT × Planck cross-spectra. We use these cross-correlations to measure the calibration of the ACT data at 148 and 218 GHz relative to Planck, to 0.7% and 2% precision respectively. We find no evidence for anisotropy in the calibration parameter. We compare the Planck 353 GHz power spectrum with the measured amplitudes of dust and cosmic infrared background (CIB) of ACT data at 148 and 218 GHz. We also compare planet and point source measurements from the two experiments.

  16. The Atacama Cosmology Telescope: cross correlation with Planck maps

    International Nuclear Information System (INIS)

    We present the temperature power spectrum of the Cosmic Microwave Background obtained by cross-correlating maps from the Atacama Cosmology Telescope (ACT) at 148 and 218 GHz with maps from the Planck satellite at 143 and 217 GHz, in two overlapping regions covering 592 square degrees. We find excellent agreement between the two datasets at both frequencies, quantified using the variance of the residuals between the ACT power spectra and the ACT × Planck cross-spectra. We use these cross-correlations to measure the calibration of the ACT data at 148 and 218 GHz relative to Planck, to 0.7% and 2% precision respectively. We find no evidence for anisotropy in the calibration parameter. We compare the Planck 353 GHz power spectrum with the measured amplitudes of dust and cosmic infrared background (CIB) of ACT data at 148 and 218 GHz. We also compare planet and point source measurements from the two experiments

  17. Cosmological constraints from $\\mu E$ cross-correlations

    CERN Document Server

    Ota, Atsuhisa

    2016-01-01

    We have derived general expressions of the $\\mu T$ and the $\\mu E$ cross-correlation functions and discussed the potential to detect these quantities. The cross-correlations are known as new tests for the extremely squeezed shape of primordial non-Gaussianity, which is inaccessible through the direct observations of the temperature 3-point functions. Our analysis is based on an experiment like PIXIE, and we found that the joint analysis improves the signal-to-noise ratio by $8.8\\%$ compared with that from the $\\mu T$ alone. Assuming that $f^{\\rm loc}_{\\rm NL}(k_1,k_2,k_3) = \\left(k_1k_2k_3\\right)^{1/3} k_0^{-1} F_0$, we also found that the scale dependent non-Gaussianity can be detectable at 2-$\\sigma$ level, even if $F_0 \\sim \\mathcal O(1)$ with $k_0=0.05{\\rm Mpc}^{-1}$.

  18. Cross-correlation markers in stochastic dynamics of complex systems

    CERN Document Server

    Panischev, O Yu; Bhattacharya, J; 10.1016/j.physa.2010.06.026

    2010-01-01

    The neuromagnetic activity (magnetoencephalogram, MEG) from healthy human brain and from an epileptic patient against chromatic flickering stimuli has been earlier analyzed on the basis of a memory functions formalism (MFF). Information measures of memory as well as relaxation parameters revealed high individuality and unique features in the neuromagnetic brain responses of each subject. The current paper demonstrates new capabilities of MFF by studying cross-correlations between MEG signals obtained from multiple and distant brain regions. It is shown that the MEG signals of healthy subjects are characterized by well-defined effects of frequency synchronization and at the same time by the domination of low-frequency processes. On the contrary, the MEG of a patient is characterized by a sharp abnormality of frequency synchronization, and also by prevalence of high-frequency quasi-periodic processes. Modification of synchronization effects and dynamics of cross-correlations offer a promising method of detectin...

  19. Phases of scaling and cross-correlation behavior in traffic

    OpenAIRE

    Kantelhardt, Jan W.;Fullerton, Matthew;Kämpf, Mirko;Beltran-Ruiz, Cristina;Busch, Fritz

    2014-01-01

    While many microscopic models of traffic flow describe transitions between different traffic phases, such transitions are difficult to quantify in measured traffic data. Here we study long-term traffic recordings consisting of ≈2900 days of flow, density, and velocity time series with minute resolution from a Spanish motorway. We calculate fluctuations, cross-correlations, and long-term persistence properties of these quantities in the flow–density diagram. This leads to a data-driven definit...

  20. Low power bitstream running cross-correlator / convolver

    OpenAIRE

    2009-01-01

    Cross-correlation gives a measure of the similarity between two signals in the time domain and is desirable in pattern matching and recognition, but other solutions are often sought after due to the heavy computational load. The work includes processing of signals in their oversampled delta sigma domain, bitstream processing, and asynchronous techniques. Employing these techniques resulted in a novel signal processing solution. This master thesis presents a power efficient implementation ...

  1. Waveform Cross-Correlation for Improved North Texas Earthquake Locations

    Science.gov (United States)

    Phillips, M.; DeShon, H. R.; Oldham, H. R.; Hayward, C.

    2014-12-01

    In November 2013, a sequence of earthquakes began in Reno and Azle, TX, two communities located northwest of Fort Worth in an area of active oil and gas extraction. Only one felt earthquake had been reported within the area before the occurrence of probable injection-induced earthquakes at the Dallas-Fort Worth airport in 2008. The USGS National Earthquakes Information Center (NEIC) has reported 27 felt earthquakes in the Reno-Azle area through January 28, 2014. A temporary seismic network was installed beginning in December 2013 to acquire data to improve location and magnitude estimates and characterize the earthquake sequence. Here, we present high-resolution relative earthquake locations derived using differential time data from waveform cross-correlation. Cross-correlation is computed using the GISMO software suite and event relocation is done using double difference relocation techniques. Waveform cross-correlation of the local data indicates high (>70%) similarity between 4 major swarms of events lasting between 18 and 24 hours. These swarms are temporal zones of high event frequency; 1.4% of the time series data accounts for 42.1% of the identified local earthquakes. Local earthquakes are occurring along the Newark East Fault System, a NE-SW striking normal fault system previously thought inactive at depths between 2 and 8 km in the Ellenburger limestone formation and underlying Precambrian basement. Data analysis is ongoing and continued characterization of the associated fault will provide improved location estimates.

  2. Cross-correlation of the cosmic 21-cm signal and Lyman Alpha Emitters during reionization

    CERN Document Server

    Sobacchi, Emanuele; Greig, Bradley

    2016-01-01

    Interferometry of the cosmic 21-cm signal is set to revolutionize our understanding of the Epoch of Reionization (EoR), eventually providing 3D maps of the early Universe. Initial detections however will be low signal-to-noise, limited by systematics. To confirm a putative 21-cm detection, and check the accuracy of 21-cm data analysis pipelines, it would be very useful to cross-correlate against a genuine cosmological signal. The most promising cosmological signals are wide-field maps of Lyman alpha emitting galaxies (LAEs), expected from the Subaru Hyper-Suprime Cam (HSC) Ultra-Deep field. Here we present estimates of the correlation between LAE maps at z~7 and the 21-cm signal observed by both the Low Frequency Array (LOFAR) and the planned Square Kilometer Array Phase 1 (SKA1). We adopt a systematic approach, varying both: (i) the prescription of assigning LAEs to host halos; and (ii) the large-scale structure of neutral and ionized regions (i.e. EoR morphology). We find that the LAE-21cm cross-correlation...

  3. Cross-correlating Planck CMB lensing with SDSS: Lensing-lensing and galaxy-lensing cross-correlations

    CERN Document Server

    Singh, Sukhdeep; Brownstein, Joel R

    2016-01-01

    We present first results from cross-correlating Planck CMB lensing maps with the Sloan Digital Sky Survey (SDSS) galaxy lensing shape catalog and BOSS galaxy catalogs. For galaxy position vs. CMB lensing cross-correlations, we measure the convergence signal around the galaxies in configuration space, using the BOSS LOWZ ($z\\sim0.30$) and CMASS ($z\\sim0.57$) samples. With fixed Planck 2015 cosmology, doing a joint fit with the galaxy clustering measurement, for the LOWZ (CMASS) sample we find a galaxy bias $b_g=1.75\\pm0.04$ ($1.95\\pm 0.02$) and galaxy-matter cross-correlation coefficient $r_{cc}=1.0\\pm0.2$ ($0.8\\pm 0.1$) using $20

  4. Radiochromic 3D Detectors

    Science.gov (United States)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  5. 3D Projection Installations

    DEFF Research Database (Denmark)

    Halskov, Kim; Johansen, Stine Liv; Bach Mikkelsen, Michelle

    2014-01-01

    Three-dimensional projection installations are particular kinds of augmented spaces in which a digital 3-D model is projected onto a physical three-dimensional object, thereby fusing the digital content and the physical object. Based on interaction design research and media studies, this article...... contributes to the understanding of the distinctive characteristics of such a new medium, and identifies three strategies for designing 3-D projection installations: establishing space; interplay between the digital and the physical; and transformation of materiality. The principal empirical case, From...... Fingerplan to Loop City, is a 3-D projection installation presenting the history and future of city planning for the Copenhagen area in Denmark. The installation was presented as part of the 12th Architecture Biennale in Venice in 2010....

  6. Herramientas SIG 3D

    Directory of Open Access Journals (Sweden)

    Francisco R. Feito Higueruela

    2010-04-01

    Full Text Available Applications of Geographical Information Systems on several Archeology fields have been increasing during the last years. Recent avances in these technologies make possible to work with more realistic 3D models. In this paper we introduce a new paradigm for this system, the GIS Thetrahedron, in which we define the fundamental elements of GIS, in order to provide a better understanding of their capabilities. At the same time the basic 3D characteristics of some comercial and open source software are described, as well as the application to some samples on archeological researchs

  7. TOWARDS: 3D INTERNET

    OpenAIRE

    Ms. Swapnali R. Ghadge

    2013-01-01

    In today’s ever-shifting media landscape, it can be a complex task to find effective ways to reach your desired audience. As traditional media such as television continue to lose audience share, one venue in particular stands out for its ability to attract highly motivated audiences and for its tremendous growth potential the 3D Internet. The concept of '3D Internet' has recently come into the spotlight in the R&D arena, catching the attention of many people, and leading to a lot o...

  8. Bootstrapping 3D fermions

    Science.gov (United States)

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-01

    We study the conformal bootstrap for a 4-point function of fermions in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge C T . We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N . We also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  9. Interaktiv 3D design

    DEFF Research Database (Denmark)

    Villaume, René Domine; Ørstrup, Finn Rude

    2002-01-01

    Projektet undersøger potentialet for interaktiv 3D design via Internettet. Arkitekt Jørn Utzons projekt til Espansiva blev udviklet som et byggesystem med det mål, at kunne skabe mangfoldige planmuligheder og mangfoldige facade- og rumudformninger. Systemets bygningskomponenter er digitaliseret som...... 3D elementer og gjort tilgængelige. Via Internettet er det nu muligt at sammenstille og afprøve en uendelig  række bygningstyper som  systemet blev tænkt og udviklet til....

  10. Random matrix approach to cross correlations in financial data

    Science.gov (United States)

    Plerou, Vasiliki; Gopikrishnan, Parameswaran; Rosenow, Bernd; Amaral, Luís A.; Guhr, Thomas; Stanley, H. Eugene

    2002-06-01

    We analyze cross correlations between price fluctuations of different stocks using methods of random matrix theory (RMT). Using two large databases, we calculate cross-correlation matrices C of returns constructed from (i) 30-min returns of 1000 US stocks for the 2-yr period 1994-1995, (ii) 30-min returns of 881 US stocks for the 2-yr period 1996-1997, and (iii) 1-day returns of 422 US stocks for the 35-yr period 1962-1996. We test the statistics of the eigenvalues λi of C against a ``null hypothesis'' - a random correlation matrix constructed from mutually uncorrelated time series. We find that a majority of the eigenvalues of C fall within the RMT bounds [λ-,λ+] for the eigenvalues of random correlation matrices. We test the eigenvalues of C within the RMT bound for universal properties of random matrices and find good agreement with the results for the Gaussian orthogonal ensemble of random matrices-implying a large degree of randomness in the measured cross-correlation coefficients. Further, we find that the distribution of eigenvector components for the eigenvectors corresponding to the eigenvalues outside the RMT bound display systematic deviations from the RMT prediction. In addition, we find that these ``deviating eigenvectors'' are stable in time. We analyze the components of the deviating eigenvectors and find that the largest eigenvalue corresponds to an influence common to all stocks. Our analysis of the remaining deviating eigenvectors shows distinct groups, whose identities correspond to conventionally identified business sectors. Finally, we discuss applications to the construction of portfolios of stocks that have a stable ratio of risk to return.

  11. Bunch Length Measurements With Laser/SR Cross-Correlation

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Timothy; /Stanford U., Phys. Dept.; Daranciang, Dan; /Stanford U., Phys. Dept.; Lindenberg, Aaron; /Stanford U., Phys. Dept.; Corbett, Jeff; /SLAC; Fisher, Alan; /SLAC; Goodfellow, John; /SLAC; Huang, Xiaobiao; /SLAC; Mok, Walter; /SLAC; Safranek, James; /SLAC; Wen, Haidan; /SLAC

    2012-07-06

    By operating SPEAR3 in low-{alpha} mode the storage ring can generate synchrotron radiation pulses of order 1ps. Applications include pump-probe x-ray science and the production of THz radiation in the CSR regime. Measurements of the bunch length are difficult, however, because the light intensity is low and streak cameras typically provide resolution of only a few ps. Tests are now underway to resolve the short bunch length using cross-correlation between a 60-fs Ti:Sapphire laser and the visible SR beam in a BBO crystal. In this paper we report on the experimental setup, preliminary measurements and prospects for further improvement.

  12. Axion inflation with cross-correlated axion isocurvature perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Kadota, Kenji [Center for Theoretical Physics of the Universe, Institute for Basic Science,Daejeon 305-811 (Korea, Republic of); Kobayashi, Tatsuo [Department of Physics, Hokkaido University,Sapporo 060-0810 (Japan); Otsuka, Hajime [Department of Physics, Waseda University,Tokyo 169-8555 (Japan)

    2016-01-25

    We study the inflation scenarios, in the framework of superstring theory, where the inflaton is an axion producing the adiabatic curvature perturbations while there exists another light axion producing the isocurvature perturbations. We discuss how the non-trivial couplings among string axions can generically arise, and calculate the consequent cross-correlations between the adiabatic and isocurvature modes through concrete examples. Based on the Planck analysis on the generally correlated isocurvature perturbations, we show that there is a preference for the existence of the correlated isocurvature modes for the axion monodromy inflation while the natural inflation disfavors such isocurvature modes.

  13. Magnetic noise measurements using cross-correlated Hall sensor arrays

    Science.gov (United States)

    Jung, G.; Ocio, M.; Paltiel, Y.; Shtrikman, H.; Zeldov, E.

    2001-01-01

    An experimental technique for measuring magnetic fluctuations by means of a double-layer Hall sensor array is described. The technique relies on cross-correlating Hall signals from two independent sensors positioned one above the other in two separate two-dimensional-electron-gas layers of a GaAs/AlGaAs heterostructure. The effectiveness of the technique is demonstrated by a reduction of the magnitude of the background noise floor of the correlated sensors with respect to the noise level of the best single sensor.

  14. Acoustic cross-correlation flowmeter for solid-gas flow

    Science.gov (United States)

    Sheen, S. H.; Raptis, A. C.

    1984-05-01

    An apparatus for measuring particle velocity in a solid-gas flow within a pipe is described. It includes: first and second transmitting transducers for transmitting first and second ultrasonic signals into the pipe at first and second locations, respectively, along the pipe; an acoustic decoupler, positioned between said first and second transmitting transducers, for acoustically isolating said first and second signals from one another; first and second detecting transducers for detecting said first and second signals and for generating first and second detected signals; and means for cross-correlating said first and second output signals.

  15. Tangible 3D Modelling

    DEFF Research Database (Denmark)

    Hejlesen, Aske K.; Ovesen, Nis

    2012-01-01

    This paper presents an experimental approach to teaching 3D modelling techniques in an Industrial Design programme. The approach includes the use of tangible free form models as tools for improving the overall learning. The paper is based on lecturer and student experiences obtained through facil...

  16. 3D Harmonic Echocardiography:

    NARCIS (Netherlands)

    M.M. Voormolen

    2007-01-01

    textabstractThree dimensional (3D) echocardiography has recently developed from an experimental technique in the ’90 towards an imaging modality for the daily clinical practice. This dissertation describes the considerations, implementation, validation and clinical application of a unique

  17. Cross-correlations between Renminbi and four major currencies in the Renminbi currency basket

    Science.gov (United States)

    Wang, Gang-Jin; Xie, Chi

    2013-03-01

    We investigate the cross-correlations between Renminbi (CNY) and four major currencies (USD, EUR, JPY, and KRW) in the Renminbi currency basket, i.e., the cross-correlations of CNY-USD, CNY-EUR, CNY-JPY, and CNY-KRW. Qualitatively, using a statistical test in analogy to the Ljung-Box test, we find that cross-correlations significantly exist in CNY-USD, CNY-EUR, CNY-JPY, and CNY-KRW. Quantitatively, employing the detrended cross-correlation analysis (DCCA) method, we find that the cross-correlations of CNY-USD, CNY-EUR, CNY-JPY, and CNY-KRW are weakly persistent. We use the DCCA cross-correlation coefficient ρ to quantify the level of cross-correlations and find the currency weight in the Renminbi currency basket is arranged in the order of USD>EUR>JPY >KRW. Using the method of rolling windows, which can capture the time-varying cross-correlation scaling exponents, we find that: (i) CNY and USD are positively cross-correlated over time, but the cross-correlations of CNY-USD are anti-persistent during the US sub-prime crisis and the European debt crisis. (ii) The cross-correlation scaling exponents of CNY-EUR have the cyclical fluctuation with a nearly two-year cycle. (iii) CNY-JPY has long-term negative cross-correlations, during the European debt crisis, but CNY and KRW are positively cross-correlated.

  18. Phases of scaling and cross-correlation behavior in traffic

    Science.gov (United States)

    Kantelhardt, Jan W.; Fullerton, Matthew; Kämpf, Mirko; Beltran-Ruiz, Cristina; Busch, Fritz

    2013-11-01

    While many microscopic models of traffic flow describe transitions between different traffic phases, such transitions are difficult to quantify in measured traffic data. Here we study long-term traffic recordings consisting of ≈2900 days of flow, density, and velocity time series with minute resolution from a Spanish motorway. We calculate fluctuations, cross-correlations, and long-term persistence properties of these quantities in the flow-density diagram. This leads to a data-driven definition of (local) traffic states based on the dynamical properties of the data, which differ from those given in standard guidelines. We find that detrending techniques must be used for persistence analysis because of non-stationary daily and weekly traffic flow patterns. We compare our results for the measured data with analysis results for a microscopic traffic model, finding good agreement in most quantities. However, the simulations cannot easily reproduce the congested traffic states observed in the data. We show how fluctuations and cross-correlations in traffic data may be used for prediction, i.e., as indications of increasing or decreasing velocities.

  19. Structure of a financial cross-correlation matrix under attack

    Science.gov (United States)

    Lim, Gyuchang; Kim, SooYong; Kim, Junghwan; Kim, Pyungsoo; Kang, Yoonjong; Park, Sanghoon; Park, Inho; Park, Sang-Bum; Kim, Kyungsik

    2009-09-01

    We investigate the structure of a perturbed stock market in terms of correlation matrices. For the purpose of perturbing a stock market, two distinct methods are used, namely local and global perturbation. The former involves replacing a correlation coefficient of the cross-correlation matrix with one calculated from two Gaussian-distributed time series while the latter reconstructs the cross-correlation matrix just after replacing the original return series with Gaussian-distributed time series. Concerning the local case, it is a technical study only and there is no attempt to model reality. The term ‘global’ means the overall effect of the replacement on other untouched returns. Through statistical analyses such as random matrix theory (RMT), network theory, and the correlation coefficient distributions, we show that the global structure of a stock market is vulnerable to perturbation. However, apart from in the analysis of inverse participation ratios (IPRs), the vulnerability becomes dull under a small-scale perturbation. This means that these analysis tools are inappropriate for monitoring the whole stock market due to the low sensitivity of a stock market to a small-scale perturbation. In contrast, when going down to the structure of business sectors, we confirm that correlation-based business sectors are regrouped in terms of IPRs. This result gives a clue about monitoring the effect of hidden intentions, which are revealed via portfolios taken mostly by large investors.

  20. Cross-correlations between Baltic Dry Index and crude oil prices

    Science.gov (United States)

    Ruan, Qingsong; Wang, Yao; Lu, Xinsheng; Qin, Jing

    2016-07-01

    This paper examines the cross-correlation properties of Baltic Dry Index (BDI) and crude oil prices using cross-correlation statistics test and multifractal detrended cross-correlation analysis (MF-DCCA). The empirical results show that the cross-correlations between BDI and crude oil prices are significantly multifractal. By introducing the concept of a "crossover", we find that the cross-correlations are strongly persistent in the short term and weakly anti-persistent in the long term. Moreover, cross-correlations of all kinds of fluctuations are persistent in the short time while cross-correlations of small fluctuations are persistent and those of large fluctuations are anti-persistent in the long term. We have also verified that the multifractality of the cross-correlations of BDI and crude oil prices is both attributable to the persistence of fluctuations of time series and fat-tailed distributions.

  1. Accelerating Radio Astronomy Cross-Correlation with Graphics Processing Units

    CERN Document Server

    Clark, M A; Greenhill, L J

    2011-01-01

    We present a highly parallel implementation of the cross-correlation of time-series data using graphics processing units (GPUs), which is scalable to hundreds of independent inputs and suitable for the processing of signals from "Large-N" arrays of many radio antennas. The computational part of the algorithm, the X-engine, is implementated efficiently on Nvidia's Fermi architecture, sustaining up to 79% of the peak single precision floating-point throughput. We compare performance obtained for hardware- and software-managed caches, observing significantly better performance for the latter. The high performance reported involves use of a multi-level data tiling strategy in memory and use of a pipelined algorithm with simultaneous computation and transfer of data from host to device memory. The speed of code development, flexibility, and low cost of the GPU implementations compared to ASIC and FPGA implementations have the potential to greatly shorten the cycle of correlator development and deployment, for case...

  2. Cross-correlation cosmography with HI intensity mapping

    CERN Document Server

    Pourtsidou, Alkistis; Crittenden, Robert

    2015-01-01

    The cross-correlation of a foreground density field with two different background convergence fields can be used to measure cosmographic distance ratios and constrain dark energy parameters. We investigate the possibility of performing such measurements using a combination of optical galaxy surveys and HI intensity mapping surveys, with emphasis on the performance of the planned Square Kilometre Array (SKA). Using HI intensity mapping to probe the foreground density tracer field and/or the background source fields has the advantage of excellent redshift resolution and a longer lever arm achieved by using the lensing signal from high redshift background sources. Our results show that, for our best SKA-optical configuration of surveys, a constant equation of state for dark energy can be constrained to $\\simeq 8\\%$ for a sky coverage $f_{\\rm sky}=0.5$ and assuming a $\\sigma(\\Omega_{\\rm DE})=0.03$ prior for the dark energy density parameter.

  3. Calibrating photometric redshift distributions with cross-correlations

    CERN Document Server

    Schulz, A E

    2009-01-01

    The next generation of proposed galaxy surveys will increase the number of galaxies with photometric redshifts by two orders of magnitude, drastically expanding both redshift range and detection threshold from the current state of the art. Obtaining spectra for a fair sub-sample of this new data could be cumbersome and expensive. However, adequate calibration of the true redshift distribution of galaxies is vital to tapping the potential of these surveys. We examine a promising alternative to direct spectroscopic follow up: calibration of the redshift distribution of photometric galaxies via cross-correlation with an overlapping spectroscopic survey whose members trace the same density field. We review the theory, develop a pipeline, apply it to mock data from N-body simulations, and examine the properties of this redshift distribution estimator. We demonstrate that the method is effective, but the estimator is weakened by two factors. 1) The correlation function of the spectroscopic sample must be measured i...

  4. Cross-correlations of ambient noise recorded by accelerometers.

    Science.gov (United States)

    Rábade García, S. E.; Ramirez-Guzman, L.

    2014-12-01

    We investigate the ambient noise cross-correlations obtained by using properly corrected accelerometric recordings, and determine velocity structure in central Mexico based on a dispersion analysis. The data used comprise ten months of continuous recordings - from April 2013 to January 2014 - of ambient seismic noise at stations operated by the National Seismological Service of Mexico and the Engineering Strong Ground Motion Network of the National Autonomous University of Mexico (UNAM). The vertical component of ambient noise was base-line corrected, filtered, and properly integrated before extracting Green's functions (GF), which were compared successfully against GF obtained using recordings from broadband velocity sensors. In order to obtain dispersion curves, we estimated group and phase velocities applying the FTAN analysis technique and obtained s-wave velocity profiles at selected regions. We conclude and highlight that the use of widely deployed accelerographs to conduct regional studies using ambient noise tomography is feasible

  5. Fluorescence cross-correlation spectroscopy using single wavelength laser

    Institute of Scientific and Technical Information of China (English)

    Chao XIE; Chaoqing DONG; Jicun REN

    2009-01-01

    In this paper, we first introduced the basic principle of fluorescence cross-correlation spectroscopy (FCCS) and then established an FCCS setup using a single wavelength laser. We systematically optimized the setup, and the detection volume reached about 0.7 fL. The home-built setup was successfully applied for the study of the binding reaction of human immunoglobulin G with goat antihuman immunoglobulin G. Using quantum dots (745 nm emission wavelength) and Rhodamine B (580 nm emission wavelength) as labeling probes and 532 nm laser beam as an excitation source, the cross-talk effect was almost completely suppressed. The molecule numbers in a highly focused volume, the concentration, and the diffusion time and hydrodynamic radii of the reaction products can be determined by FCCS system.

  6. Imaging the Yellowstone Magmatic System Using Multi-Component Ambient Noise Cross-Correlation and Tomography

    Science.gov (United States)

    Farrell, J.; Lin, F. C.

    2015-12-01

    We present a new S-wave velocity model for the Yellowstone magmatic system derived from the inversion of Rayleigh- and Love-wave phase velocity measurements from periods from 6 to 35 s. All available data from 2007-2014 within and near the Yellowstone region was downloaded for the USArray TA network (TA), the Yellowstone Seismic Network (WY), the NOISY array (Z2), the USGS Intermountain West network (IW), the Plate Boundary Observatory Borehole Seismic Network (PB), and the USGS National Seismic Network (US). For each station, we perform daily noise pre-processing (temporal normalization and spectrum whitening) simultaneously for all three components before multi-component noise cross-correlations are calculated. Results for both Rayleigh- and Love-wave phase velocity inversions clearly show the low velocity anomaly associated with the upper-crustal magma reservoir seen previously using body wave tomography. In addition, low-velocity anomalies associated with sediment-filled basins are visible in Wyoming. Short period low Love-wave velocities are seen along the Snake River Plain, the track of the Yellowstone hotspot likely related to the shallow sediment layer. Based on the surface wave phase velocity maps, we invert for a 3D S-wave crustal model. The resulting model will be compared to previous, but spatially limited, body wave S-wave models as well as recent body wave P-wave velocity models to better constrain Vp/Vs ratios as well as the melt fraction of the magma chamber. Preliminary results using amplitude information of noise cross-correlations to calculate Rayleigh-wave ellipticity, or Rayleigh-wave H/V (horizontal to vertical) amplitude ratios to better constrain the shallow velocity structure will also be discussed.

  7. Massive 3D Supergravity

    CERN Document Server

    Andringa, Roel; de Roo, Mees; Hohm, Olaf; Sezgin, Ergin; Townsend, Paul K

    2009-01-01

    We construct the N=1 three-dimensional supergravity theory with cosmological, Einstein-Hilbert, Lorentz Chern-Simons, and general curvature squared terms. We determine the general supersymmetric configuration, and find a family of supersymmetric adS vacua with the supersymmetric Minkowski vacuum as a limiting case. Linearizing about the Minkowski vacuum, we find three classes of unitary theories; one is the supersymmetric extension of the recently discovered `massive 3D gravity'. Another is a `new topologically massive supergravity' (with no Einstein-Hilbert term) that propagates a single (2,3/2) helicity supermultiplet.

  8. Massive 3D supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Andringa, Roel; Bergshoeff, Eric A; De Roo, Mees; Hohm, Olaf [Centre for Theoretical Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Sezgin, Ergin [George and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Townsend, Paul K, E-mail: E.A.Bergshoeff@rug.n, E-mail: O.Hohm@rug.n, E-mail: sezgin@tamu.ed, E-mail: P.K.Townsend@damtp.cam.ac.u [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)

    2010-01-21

    We construct the N=1 three-dimensional supergravity theory with cosmological, Einstein-Hilbert, Lorentz Chern-Simons, and general curvature squared terms. We determine the general supersymmetric configuration, and find a family of supersymmetric adS vacua with the supersymmetric Minkowski vacuum as a limiting case. Linearizing about the Minkowski vacuum, we find three classes of unitary theories; one is the supersymmetric extension of the recently discovered 'massive 3D gravity'. Another is a 'new topologically massive supergravity' (with no Einstein-Hilbert term) that propagates a single (2,3/2) helicity supermultiplet.

  9. 3D Digital Modelling

    DEFF Research Database (Denmark)

    Hundebøl, Jesper

    ABSTRACT: Lack of productivity in construction is a well known issue. Despite the fact that causes hereof are multiple, the introduction of information technology is a frequently observed response to almost any challenge. ICT in construction is a thoroughly researched matter, however, the current...... important to appreciate the analysis. Before turning to the presentation of preliminary findings and a discussion of 3D digital modelling, it begins, however, with an outline of industry specific ICT strategic issues. Paper type. Multi-site field study...

  10. TOWARDS: 3D INTERNET

    Directory of Open Access Journals (Sweden)

    Ms. Swapnali R. Ghadge

    2013-08-01

    Full Text Available In today’s ever-shifting media landscape, it can be a complex task to find effective ways to reach your desired audience. As traditional media such as television continue to lose audience share, one venue in particular stands out for its ability to attract highly motivated audiences and for its tremendous growth potential the 3D Internet. The concept of '3D Internet' has recently come into the spotlight in the R&D arena, catching the attention of many people, and leading to a lot of discussions. Basically, one can look into this matter from a few different perspectives: visualization and representation of information, and creation and transportation of information, among others. All of them still constitute research challenges, as no products or services are yet available or foreseen for the near future. Nevertheless, one can try to envisage the directions that can be taken towards achieving this goal. People who take part in virtual worlds stay online longer with a heightened level of interest. To take advantage of that interest, diverse businesses and organizations have claimed an early stake in this fast-growing market. They include technology leaders such as IBM, Microsoft, and Cisco, companies such as BMW, Toyota, Circuit City, Coca Cola, and Calvin Klein, and scores of universities, including Harvard, Stanford and Penn State.

  11. The use of synthetic master events for waveform cross correlation

    Science.gov (United States)

    Rozhkov, Mikhail; Bobrov, Dmitry; Kitov, Ivan

    2013-04-01

    It has been clearly demonstrated that waveform cross correlation substantially improves signal detection, phase association and event building. These processes are inherently related to the Comprehensive Nuclear-Test-Ban Treaty (CTBT) monitoring. The workhorse of cross correlation is the set of seismic master events (earthquakes or explosions) with high quality waveform templates recorded at array stations of the International Monitoring System (IMS). For the monitoring to be globally uniform, these master events have to be evenly distributed and their template waveforms should be representative and pure. However, global seismicity is characterized by a non-uniform distribution. Therefore, the master events selected from the Reviewed Event Bulletin (REB) produced by the International Data Centre (IDC) can be found in the areas constrained by the global seismicity. There are two principal possibilities to populate the globe with master events: to replicate real REB events or to build synthetic events. Here we compare the performance of these two approaches as applied to the aftershock sequence of the April 11, 2012 Sumatera earthquake. To compute synthetic waveforms, we use AK135 teleseismic velocity model and local CRUST-2 models for source and receiver, and four different source functions representing three different source mechanisms for earthquakes and one for explosion. The synthetic modeling is performed for teleseismic events and based on the stationary phase approximation to a wave equation solution developed by J. Hudson. The grid covering the aftershock area consists of 16 points. For each grid point, we find detections associated with real, replicated, and four versions of synthetic master events at seven IMS array stations, and then build event hypothesis using the Local Association (LA) procedure based on the clustering of origin times as estimated by back projection of the relevant arrival times with known master/station travel times. Then all

  12. Shaping 3-D boxes

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Madsen, Claus B.

    2011-01-01

    Enabling users to shape 3-D boxes in immersive virtual environments is a non-trivial problem. In this paper, a new family of techniques for creating rectangular boxes of arbitrary position, orientation, and size is presented and evaluated. These new techniques are based solely on position data......, making them different from typical, existing box shaping techniques. The basis of the proposed techniques is a new algorithm for constructing a full box from just three of its corners. The evaluation of the new techniques compares their precision and completion times in a 9 degree-of-freedom (Do......F) docking experiment against an existing technique, which requires the user to perform the rotation and scaling of the box explicitly. The precision of the users' box construction is evaluated by a novel error metric measuring the difference between two boxes. The results of the experiment strongly indicate...

  13. Parameterization of real-time 3D speckle tracking framework for cardiac strain assessment.

    Science.gov (United States)

    Lorsakul, Auranuch; Duan, Qi; Po, Ming Jack; Angelini, Elsa; Homma, Shunichi; Laine, Andrew F

    2011-01-01

    Cross-correlation based 3D speckle tracking algorithm can be used to automatically track myocardial motion on three dimensional real-time (RT3D) echocardiography. The goal of this study was to experimentally investigate the effects of different parameters associated with such algorithm to ensure accurate cardiac strain measurements. The investigation was performed on 10 chronic obstructive pulmonary disease RT3DE cardiac ultrasound images. The following two parameters were investigated: 1) the gradient threshold of the anisotropic diffusion pre-filtering and 2) the window size of the cross correlation template matching in the speckle tracking. Results suggest that the optimal gradient threshold of the anisotropic filter depends on the average gradient of the background speckle noise, and that an optimal pair of template size and search window size can be identified determines the cross-correlation level and computational cost. PMID:22254887

  14. Blind Cartography for Side Channel Attacks: Cross-Correlation Cartography

    Directory of Open Access Journals (Sweden)

    Laurent Sauvage

    2012-01-01

    Full Text Available Side channel and fault injection attacks are major threats to cryptographic applications of embedded systems. Best performances for these attacks are achieved by focusing sensors or injectors on the sensible parts of the application, by means of dedicated methods to localise them. Few methods have been proposed in the past, and all of them aim at pinpointing the cryptoprocessor. However it could be interesting to exploit the activity of other parts of the application, in order to increase the attack's efficiency or to bypass its countermeasures. In this paper, we present a localisation method based on cross-correlation, which issues a list of areas of interest within the attacked device. It realizes an exhaustive analysis, since it may localise any module of the device, and not only those which perform cryptographic operations. Moreover, it also does not require a preliminary knowledge about the implementation, whereas some previous cartography methods require that the attacker could choose the cryptoprocessor inputs, which is not always possible. The method is experimentally validated using observations of the electromagnetic near field distribution over a Xilinx Virtex 5 FPGA. The matching between areas of interest and the application layout in the FPGA floorplan is confirmed by correlation analysis.

  15. 3D printing for dummies

    CERN Document Server

    Hausman, Kalani Kirk

    2014-01-01

    Get started printing out 3D objects quickly and inexpensively! 3D printing is no longer just a figment of your imagination. This remarkable technology is coming to the masses with the growing availability of 3D printers. 3D printers create 3-dimensional layered models and they allow users to create prototypes that use multiple materials and colors.  This friendly-but-straightforward guide examines each type of 3D printing technology available today and gives artists, entrepreneurs, engineers, and hobbyists insight into the amazing things 3D printing has to offer. You'll discover methods for

  16. Martian terrain - 3D

    Science.gov (United States)

    1997-01-01

    This area of terrain near the Sagan Memorial Station was taken on Sol 3 by the Imager for Mars Pathfinder (IMP). 3D glasses are necessary to identify surface detail.The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.' It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  17. 3D monitor

    OpenAIRE

    Szkandera, Jan

    2009-01-01

    Tato bakalářská práce se zabývá návrhem a realizací systému, který umožní obraz scény zobrazovaný na ploše vnímat prostorově. Prostorové vnímání 2D obrazové informace je umožněno jednak stereopromítáním a jednak tím, že se obraz mění v závislosti na poloze pozorovatele. Tato práce se zabývá hlavně druhým z těchto problémů. This Bachelor's thesis goal is to design and realize system, which allows user to perceive 2D visual information as three-dimensional. 3D visual preception of 2D image i...

  18. Cross-correlation Weak Lensing of SDSS Galaxy Clusters III: Mass-to-light Ratios

    CERN Document Server

    Sheldon, Erin S; Masjedi, Morad; McKay, Timothy A; Blanton, Michael R; Scranton, Ryan; Wechsler, Risa H; Koester, Ben P; Hansen, Sarah M; Frieman, Joshua A; Annis, James

    2007-01-01

    We present measurements of the excess mass-to-light ratio (M/L) measured around MaxBCG galaxy clusters observed in the SDSS. Using cross-correlation weak lensing, we measure the excess mass density profile above the universal mean \\Delta \\rho(r) = \\rho(r) - \\bar{\\rho} for clusters in bins of richness and optical luminosity. We also measure the excess ^{0.25}i-band luminosity density \\Delta l(r) = l(r) - \\bar{l}. For both mass and light, we de-project the profiles to produce 3D mass and light profiles over scales from 25 kpc/h to 22 Mpc/h. From these profiles we calculate the cumulative excess mass \\Delta M(r) and excess light \\Delta L(r) as a function of separation from the BCG. On small scales, where \\rho(r) >> \\bar{\\rho}, the integrated M/L profile may be interpreted as the cluster M/L. We find the (\\Delta M/\\Delta L)_{200}, the M/L within r_{200}, scales with cluster mass as a power law with index 0.33+/-0.02. On large scales, where \\rho(r) . We find /b^2_{ml} = 362+/-54 h measured in the ^{0.25}i-bandpass...

  19. Multifractal detrended cross-correlation analysis of carbon and crude oil markets

    Science.gov (United States)

    Zhuang, Xiaoyang; Wei, Yu; Zhang, Bangzheng

    2014-04-01

    The complex dynamics between carbon and crude oil markets have been an increasingly interesting area of research. In this paper, we try to take a fresh look at the cross-correlations between carbon and crude oil markets as well as their dynamic behavior employing multifractal detrended cross-correlation analysis. First, we find that the return series of carbon and crude oil markets are significantly cross-correlated. Second, we confirm the existence of multifractality for the return series of carbon and crude oil markets by the multifractal detrended fluctuation analysis. Third, based on the multifractal detrended cross-correlation analysis, we find the existence of power-law cross-correlations between carbon and crude oil markets. The cross-correlated behavior of small fluctuations is found to be more persistent than that of large fluctuations. At last, some relevant discussions and implications of the empirical results are presented.

  20. 3D game environments create professional 3D game worlds

    CERN Document Server

    Ahearn, Luke

    2008-01-01

    The ultimate resource to help you create triple-A quality art for a variety of game worlds; 3D Game Environments offers detailed tutorials on creating 3D models, applying 2D art to 3D models, and clear concise advice on issues of efficiency and optimization for a 3D game engine. Using Photoshop and 3ds Max as his primary tools, Luke Ahearn explains how to create realistic textures from photo source and uses a variety of techniques to portray dynamic and believable game worlds.From a modern city to a steamy jungle, learn about the planning and technological considerations for 3D modelin

  1. X3D: Extensible 3D Graphics Standard

    OpenAIRE

    Daly, Leonard; Brutzman, Don

    2007-01-01

    The article of record as published may be located at http://dx.doi.org/10.1109/MSP.2007.905889 Extensible 3D (X3D) is the open standard for Web-delivered three-dimensional (3D) graphics. It specifies a declarative geometry definition language, a run-time engine, and an application program interface (API) that provide an interactive, animated, real-time environment for 3D graphics. The X3D specification documents are freely available, the standard can be used without paying any royalties,...

  2. 3D Printing an Octohedron

    OpenAIRE

    Aboufadel, Edward F.

    2014-01-01

    The purpose of this short paper is to describe a project to manufacture a regular octohedron on a 3D printer. We assume that the reader is familiar with the basics of 3D printing. In the project, we use fundamental ideas to calculate the vertices and faces of an octohedron. Then, we utilize the OPENSCAD program to create a virtual 3D model and an STereoLithography (.stl) file that can be used by a 3D printer.

  3. Salient Local 3D Features for 3D Shape Retrieval

    CERN Document Server

    Godil, Afzal

    2011-01-01

    In this paper we describe a new formulation for the 3D salient local features based on the voxel grid inspired by the Scale Invariant Feature Transform (SIFT). We use it to identify the salient keypoints (invariant points) on a 3D voxelized model and calculate invariant 3D local feature descriptors at these keypoints. We then use the bag of words approach on the 3D local features to represent the 3D models for shape retrieval. The advantages of the method are that it can be applied to rigid as well as to articulated and deformable 3D models. Finally, this approach is applied for 3D Shape Retrieval on the McGill articulated shape benchmark and then the retrieval results are presented and compared to other methods.

  4. 3D modelling and recognition

    OpenAIRE

    Rodrigues, Marcos; Robinson, Alan; Alboul, Lyuba; Brink, Willie

    2006-01-01

    3D face recognition is an open field. In this paper we present a method for 3D facial recognition based on Principal Components Analysis. The method uses a relatively large number of facial measurements and ratios and yields reliable recognition. We also highlight our approach to sensor development for fast 3D model acquisition and automatic facial feature extraction.

  5. Random matrix theory analysis of cross-correlations in the US stock market: Evidence from Pearson’s correlation coefficient and detrended cross-correlation coefficient

    Science.gov (United States)

    Wang, Gang-Jin; Xie, Chi; Chen, Shou; Yang, Jiao-Jiao; Yang, Ming-Yan

    2013-09-01

    In this study, we first build two empirical cross-correlation matrices in the US stock market by two different methods, namely the Pearson’s correlation coefficient and the detrended cross-correlation coefficient (DCCA coefficient). Then, combining the two matrices with the method of random matrix theory (RMT), we mainly investigate the statistical properties of cross-correlations in the US stock market. We choose the daily closing prices of 462 constituent stocks of S&P 500 index as the research objects and select the sample data from January 3, 2005 to August 31, 2012. In the empirical analysis, we examine the statistical properties of cross-correlation coefficients, the distribution of eigenvalues, the distribution of eigenvector components, and the inverse participation ratio. From the two methods, we find some new results of the cross-correlations in the US stock market in our study, which are different from the conclusions reached by previous studies. The empirical cross-correlation matrices constructed by the DCCA coefficient show several interesting properties at different time scales in the US stock market, which are useful to the risk management and optimal portfolio selection, especially to the diversity of the asset portfolio. It will be an interesting and meaningful work to find the theoretical eigenvalue distribution of a completely random matrix R for the DCCA coefficient because it does not obey the Marčenko-Pastur distribution.

  6. Big Data Solution for CTBT Monitoring Using Global Cross Correlation

    Science.gov (United States)

    Gaillard, P.; Bobrov, D.; Dupont, A.; Grenouille, A.; Kitov, I. O.; Rozhkov, M.

    2014-12-01

    Due to the mismatch between data volume and the performance of the Information Technology infrastructure used in seismic data centers, it becomes more and more difficult to process all the data with traditional applications in a reasonable elapsed time. To fulfill their missions, the International Data Centre of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO/IDC) and the Département Analyse Surveillance Environnement of Commissariat à l'Energie atomique et aux énergies alternatives (CEA/DASE) collect, process and produce complex data sets whose volume is growing exponentially. In the medium term, computer architectures, data management systems and application algorithms will require fundamental changes to meet the needs. This problem is well known and identified as a "Big Data" challenge. To tackle this major task, the CEA/DASE takes part during two years to the "DataScale" project. Started in September 2013, DataScale gathers a large set of partners (research laboratories, SMEs and big companies). The common objective is to design efficient solutions using the synergy between Big Data solutions and the High Performance Computing (HPC). The project will evaluate the relevance of these technological solutions by implementing a demonstrator for seismic event detections thanks to massive waveform correlations. The IDC has developed an expertise on such techniques leading to an algorithm called "Master Event" and provides a high-quality dataset for an extensive cross correlation study. The objective of the project is to enhance the Master Event algorithm and to reanalyze 10 years of waveform data from the International Monitoring System (IMS) network thanks to a dedicated HPC infrastructure operated by the "Centre de Calcul Recherche et Technologie" at the CEA of Bruyères-le-Châtel. The dataset used for the demonstrator includes more than 300,000 seismic events, tens of millions of raw detections and more than 30 terabytes of continuous seismic data

  7. How to detect Edgar Allan Poe's 'purloined letter,' or cross-correlation algorithms in digitized video images for object identification, movement evaluation, and deformation analysis

    Science.gov (United States)

    Dost, Michael; Vogel, Dietmar; Winkler, Thomas; Vogel, Juergen; Erb, Rolf; Kieselstein, Eva; Michel, Bernd

    2003-07-01

    Cross correlation analysis of digitised grey scale patterns is based on - at least - two images which are compared one to each other. Comparison is performed by means of a two-dimensional cross correlation algorithm applied to a set of local intensity submatrices taken from the pattern matrices of the reference and the comparison images in the surrounding of predefined points of interest. Established as an outstanding NDE tool for 2D and 3D deformation field analysis with a focus on micro- and nanoscale applications (microDAC and nanoDAC), the method exhibits an additional potential for far wider applications, that could be used for advancing homeland security. Cause the cross correlation algorithm in some kind seems to imitate some of the "smart" properties of human vision, this "field-of-surface-related" method can provide alternative solutions to some object and process recognition problems that are difficult to solve with more classic "object-related" image processing methods. Detecting differences between two or more images using cross correlation techniques can open new and unusual applications in identification and detection of hidden objects or objects with unknown origin, in movement or displacement field analysis and in some aspects of biometric analysis, that could be of special interest for homeland security.

  8. CFHTLenS and RCSLenS: Testing Photometric Redshift Distributions Using Angular Cross-Correlations with Spectroscopic Galaxy Surveys

    Science.gov (United States)

    Choi, A.; Heymans, C.; Blake, C.; Hildebrandt, H.; Duncan, C. A. J.; Erben, T.; Nakajima, R.; Van Waerbeke, L.; Viola, M.

    2016-09-01

    We determine the accuracy of galaxy redshift distributions as estimated from photometric redshift probability distributions p(z). Our method utilises measurements of the angular cross-correlation between photometric galaxies and an overlapping sample of galaxies with spectroscopic redshifts. We describe the redshift leakage from a galaxy photometric redshift bin j into a spectroscopic redshift bin i using the sum of the p(z) for the galaxies residing in bin j. We can then predict the angular cross-correlation between photometric and spectroscopic galaxies due to intrinsic galaxy clustering when i ≠ j as a function of the measured angular cross-correlation when i = j. We also account for enhanced clustering arising from lensing magnification using a halo model. The comparison of this prediction with the measured signal provides a consistency check on the validity of using the summed p(z) to determine galaxy redshift distributions in cosmological analyses, as advocated by the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). We present an analysis of the photometric redshifts measured by CFHTLenS, which overlaps the Baryon Oscillation Spectroscopic Survey (BOSS). We also analyse the Red-sequence Cluster Lensing Survey (RCSLenS), which overlaps both BOSS and the WiggleZ Dark Energy Survey. We find that the summed p(z) from both surveys are generally biased with respect to the true underlying distributions. If unaccounted for, this bias would lead to errors in cosmological parameter estimation from CFHTLenS by less than ˜4%. For photometric redshift bins which spatially overlap in 3-D with our spectroscopic sample, we determine redshift bias corrections which can be used in future cosmological analyses that rely on accurate galaxy redshift distributions.

  9. Cross-correlations between crude oil and exchange markets for selected oil rich economies

    Science.gov (United States)

    Li, Jianfeng; Lu, Xinsheng; Zhou, Ying

    2016-07-01

    Using multifractal detrended cross-correlation analysis (MF-DCCA), this paper studies the cross-correlation behavior between crude oil market and five selected exchange rate markets. The dataset covers the period of January 1,1996-December 31,2014, and contains 4,633 observations for each of the series, including daily closing prices of crude oil, Australian Dollars, Canadian Dollars, Mexican Pesos, Russian Rubles, and South African Rand. Our empirical results obtained from cross-correlation statistic and cross-correlation coefficient have confirmed the existence of cross-correlations, and the MF-DCCA results have demonstrated a strong multifractality between cross-correlated crude oil market and exchange rate markets in both short term and long term. Using rolling window analysis, we have also found the persistent cross-correlations between the exchange rates and crude oil returns, and the cross-correlation scaling exponents exhibit volatility during some time periods due to its sensitivity to sudden events.

  10. An analysis of the intrinsic cross-correlations between API and meteorological elements using DPCCA

    Science.gov (United States)

    Shen, Chen-hua; Li, Cao-ling

    2016-03-01

    In order to reveal the intrinsic cross-correlations between air pollution index (API) records and synchronously meteorological elements data, the detrended partial cross-correlation (DPCC) coefficients are analyzed using a detrended partial cross-correlation analysis (DPCCA). DPCC coefficients for different spatial locations and seasons are calculated and compared. The results show that DPCCA can uncover intrinsic cross-correlations between API and meteorological elements, and most of their interactional mechanisms can be explained. DPCC coefficients are either positive or negative, and vary with spatial locations and seasons, with consistently interactional mechanisms. More remarkable, we find that detrended cross-correlation analysis can present the cross-correlations between the fluctuations in two nonstationary time series, but this cross-correlation does not always fully reflect the interactional mechanism for the original time series. Despite this, DPCCA is recommended as a comparatively reliable method for revealing intrinsic cross-correlations between API and meteorological elements, and it can also be useful for our understanding of their interactional mechanisms.

  11. Cross-correlations between price and volume in Chinese gold markets

    Science.gov (United States)

    Ruan, Qingsong; Jiang, Wei; Ma, Guofeng

    2016-06-01

    We apply the multifractal detrended cross-correlation analysis (MF-DCCA) method to investigate the cross-correlation behaviors between price and volume in Chinese gold spot and futures markets. Qualitatively, we find that the price and volume series are significantly cross-correlated using the cross-correlation test statistics Qcc(m) and the ρDCCA coefficients. Quantitatively, by employing the MF-DCCA analysis, we find that there is a power-law cross-correlation and significant multifractal features between price and volume in gold spot and futures markets. Furthermore, by comparing the multifractality of the original series to the shuffled and surrogated series, we find that, for the gold spot market, the main contribution of multifractality is fat-tail distribution; for the gold futures market, both long-range correlations and fat-tail distributions play important roles in the contribution of multifractality. Finally, by employing the method of rolling windows, we undertake further investigation into the time-varying features of the cross-correlations between price and volume. We find that for both spot and futures markets, the cross-correlations are anti-persistent in general. In the short term, the cross-correlation shows obvious fluctuations due to exogenous shocks while, in the long term, the relationship tends to be at a metastable level due to the dynamic mechanism.

  12. Artifacts in blood velocity estimation using ultrasound and cross-correlation

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    1994-01-01

    Estimation of blood velocities using ultrasound and time-domain cross-correlation is investigated. The measurement principle is introduced, and the basic properties of the cross-correlation function are discussed. Expressions for the variance of the estimates of the peak location are given, showi...

  13. Cross-Correlation Properties of Costas Arrays and Their Images under Horizontal and Vertical Flips

    Directory of Open Access Journals (Sweden)

    Konstantinos Drakakis

    2008-01-01

    Full Text Available We consider the cross-correlation of a Costas array with its image under a horizontal and/or a vertical flip. We propose and prove several bounds on the maximal cross-correlation and on its value at the origin, for both general Costas arrays and for algebraically constructed ones.

  14. Stationary-phase integrals in the cross correlation of ambient noise

    NARCIS (Netherlands)

    Boschi, L.; Weemstra, C.

    2015-01-01

    The cross correlation of ambient signal allows seismologists to collect data even in the absence of seismic events. “Seismic interferometry” shows that the cross correlation of simultaneous recordings of a random wavefield made at two locations is formally related to the impulse response between tho

  15. Asymptotic Analysis of Estimated Cyclic Cross-Correlation Function Between Stationary and Cyclostationary Processes

    Institute of Scientific and Technical Information of China (English)

    黄知涛; 王炜华; 周一宇; 姜文利

    2003-01-01

    The cyclic cross-correlation between a stationary process and a cyclostationary process at cycle frequency α( ≠ 0)is identically zero under an ideal condition, which indicates that a cyclic cross-correlation method performs much better than the conventional cross-correlation method in suppressing the stationary noise or interference. But unfortunately, the cyclic cross-correlation will not really approach zero due to the limited data length in some real conditions. In this paper,the quantitative relation between the data length and the estimated cyclic cross-correlation is deduced, and some useful conclusions are drawn, which are proven by some computer simulations. The conclusion in this paper is really useful for the practical application of cyclostationary signal processing.

  16. 3D-skannaukseen perehtyminen

    OpenAIRE

    Santaluoto, Olli

    2012-01-01

    Tässä insinöörityössä tarkastellaan erilaisia 3D-skannaustekniikoita ja menetelmiä. Työssä myös kerrotaan esimerkkien avulla eri 3D-skannaustekniikoiden käyttökohteista. 3D-skannaus on Suomessa vielä melko harvinaista, siksi eri tekniikat ja käyttömahdollisuudet ovat monille tuntemattomia. 3D-skanneri on laite, jolla tutkitaan reaalimaailman esineitä tai ympäristöä keräämällä dataa kohteen muodoista. 3D-skannerit ovat hyvin paljon vastaavia tavallisen kameran kanssa. Kuten kameroilla, 3D...

  17. Cross-Correlations between Energy and Emissions Markets: New Evidence from Fractal and Multifractal Analysis

    Directory of Open Access Journals (Sweden)

    Gang-Jin Wang

    2014-01-01

    Full Text Available We supply a new perspective to describe and understand the behavior of cross-correlations between energy and emissions markets. Namely, we investigate cross-correlations between oil and gas (Oil-Gas, oil and CO2 (Oil-CO2, and gas and CO2 (Gas-CO2 based on fractal and multifractal analysis. We focus our study on returns of the oil, gas, and CO2 during the period of April 22, 2005–April 30, 2013. In the empirical analysis, by using the detrended cross-correlation analysis (DCCA method, we find that cross-correlations for Oil-Gas, Oil-CO2, and Gas-CO2 obey a power-law and are weakly persistent. Then, we adopt the method of DCCA cross-correlation coefficient to quantify cross-correlations between energy and emissions markets. The results show that their cross-correlations are diverse at different time scales. Next, based on the multifractal DCCA method, we find that cross-correlated markets have the nonlinear and multifractal nature and that the multifractality strength for three cross-correlated markets is arranged in the order of Gas-CO2 > Oil-Gas > Oil-CO2. Finally, by employing the rolling windows method, which can be used to investigate time-varying cross-correlation scaling exponents, we analyze short-term and long-term market dynamics and find that the recent global financial crisis has a notable influence on short-term and long-term market dynamics.

  18. 3D Printing Functional Nanocomposites

    OpenAIRE

    Leong, Yew Juan

    2016-01-01

    3D printing presents the ability of rapid prototyping and rapid manufacturing. Techniques such as stereolithography (SLA) and fused deposition molding (FDM) have been developed and utilized since the inception of 3D printing. In such techniques, polymers represent the most commonly used material for 3D printing due to material properties such as thermo plasticity as well as its ability to be polymerized from monomers. Polymer nanocomposites are polymers with nanomaterials composited into the ...

  19. 3D Elevation Program—Virtual USA in 3D

    Science.gov (United States)

    Lukas, Vicki; Stoker, J.M.

    2016-01-01

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.  

  20. 3D IBFV : Hardware-Accelerated 3D Flow Visualization

    NARCIS (Netherlands)

    Telea, Alexandru; Wijk, Jarke J. van

    2003-01-01

    We present a hardware-accelerated method for visualizing 3D flow fields. The method is based on insertion, advection, and decay of dye. To this aim, we extend the texture-based IBFV technique for 2D flow visualization in two main directions. First, we decompose the 3D flow visualization problem in a

  1. Interactive 3D multimedia content

    CERN Document Server

    Cellary, Wojciech

    2012-01-01

    The book describes recent research results in the areas of modelling, creation, management and presentation of interactive 3D multimedia content. The book describes the current state of the art in the field and identifies the most important research and design issues. Consecutive chapters address these issues. These are: database modelling of 3D content, security in 3D environments, describing interactivity of content, searching content, visualization of search results, modelling mixed reality content, and efficient creation of interactive 3D content. Each chapter is illustrated with example a

  2. 3D Bayesian contextual classifiers

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    2000-01-01

    We extend a series of multivariate Bayesian 2-D contextual classifiers to 3-D by specifying a simultaneous Gaussian distribution for the feature vectors as well as a prior distribution of the class variables of a pixel and its 6 nearest 3-D neighbours.......We extend a series of multivariate Bayesian 2-D contextual classifiers to 3-D by specifying a simultaneous Gaussian distribution for the feature vectors as well as a prior distribution of the class variables of a pixel and its 6 nearest 3-D neighbours....

  3. 3-D printers for libraries

    CERN Document Server

    Griffey, Jason

    2014-01-01

    As the maker movement continues to grow and 3-D printers become more affordable, an expanding group of hobbyists is keen to explore this new technology. In the time-honored tradition of introducing new technologies, many libraries are considering purchasing a 3-D printer. Jason Griffey, an early enthusiast of 3-D printing, has researched the marketplace and seen several systems first hand at the Consumer Electronics Show. In this report he introduces readers to the 3-D printing marketplace, covering such topics asHow fused deposition modeling (FDM) printing workBasic terminology such as build

  4. 3D for Graphic Designers

    CERN Document Server

    Connell, Ellery

    2011-01-01

    Helping graphic designers expand their 2D skills into the 3D space The trend in graphic design is towards 3D, with the demand for motion graphics, animation, photorealism, and interactivity rapidly increasing. And with the meteoric rise of iPads, smartphones, and other interactive devices, the design landscape is changing faster than ever.2D digital artists who need a quick and efficient way to join this brave new world will want 3D for Graphic Designers. Readers get hands-on basic training in working in the 3D space, including product design, industrial design and visualization, modeling, ani

  5. Using 3D in Visualization

    DEFF Research Database (Denmark)

    Wood, Jo; Kirschenbauer, Sabine; Döllner, Jürgen;

    2005-01-01

    to display 3D imagery. The extra cartographic degree of freedom offered by using 3D is explored and offered as a motivation for employing 3D in visualization. The use of VR and the construction of virtual environments exploit navigational and behavioral realism, but become most usefil when combined...... with abstracted representations embedded in a 3D space. The interactions between development of geovisualization, the technology used to implement it and the theory surrounding cartographic representation are explored. The dominance of computing technologies, driven particularly by the gaming industry...

  6. An automatic approach for 3D registration of CT scans

    Science.gov (United States)

    Hu, Yang; Saber, Eli; Dianat, Sohail; Vantaram, Sreenath Rao; Abhyankar, Vishwas

    2012-03-01

    CT (Computed tomography) is a widely employed imaging modality in the medical field. Normally, a volume of CT scans is prescribed by a doctor when a specific region of the body (typically neck to groin) is suspected of being abnormal. The doctors are required to make professional diagnoses based upon the obtained datasets. In this paper, we propose an automatic registration algorithm that helps healthcare personnel to automatically align corresponding scans from 'Study' to 'Atlas'. The proposed algorithm is capable of aligning both 'Atlas' and 'Study' into the same resolution through 3D interpolation. After retrieving the scanned slice volume in the 'Study' and the corresponding volume in the original 'Atlas' dataset, a 3D cross correlation method is used to identify and register various body parts.

  7. Improvement of 3D Scanner

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The disadvantage remaining in 3D scanning system and its reasons are discussed. A new host-and-slave structure with high speed image acquisition and processing system is proposed to quicken the image processing and improve the performance of 3D scanning system.

  8. 3D Printing for Bricks

    OpenAIRE

    ECT Team, Purdue

    2015-01-01

    Building Bytes, by Brian Peters, is a project that uses desktop 3D printers to print bricks for architecture. Instead of using an expensive custom-made printer, it uses a normal standard 3D printer which is available for everyone and makes it more accessible and also easier for fabrication.

  9. 3D printing in dentistry.

    Science.gov (United States)

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery. PMID:26657435

  10. 3D printing in dentistry.

    Science.gov (United States)

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.

  11. PLOT3D user's manual

    Science.gov (United States)

    Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.

    1990-01-01

    PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.

  12. Cross-correlation between thermal Sunyaev-Zeldovich effect and the integrated Sachs-Wolfe effect

    CERN Document Server

    Creque-Sarbinowski, Cyril; Kamionkowski, Marc

    2016-01-01

    Large-angle fluctuations in the cosmic microwave background (CMB) temperature induced by the integrated Sachs-Wolfe (ISW) effect and Compton-y distortions from the thermal Sunyaev-Zeldovich (tSZ) effect are both due to line-of-sight density perturbations. Here we calculate the cross-correlation between these two signals. Measurement of this cross-correlation can be used to test the redshift distribution of the tSZ distortion. We also evaluate the detectability of a yT cross-correlation from exotic early-Universe sources in the presence of this late-time effect.

  13. 3-D Video Processing for 3-D TV

    Science.gov (United States)

    Sohn, Kwanghoon; Kim, Hansung; Kim, Yongtae

    One of the most desirable ways of realizing high quality information and telecommunication services has been called "The Sensation of Reality," which can be achieved by visual communication based on 3-D (Three-dimensional) images. These kinds of 3-D imaging systems have revealed potential applications in the fields of education, entertainment, medical surgery, video conferencing, etc. Especially, three-dimensional television (3-D TV) is believed to be the next generation of TV technology. Figure 13.1 shows how TV's display technologies have evolved , and Fig. 13.2 details the evolution of TV broadcasting as forecasted by the ETRI (Electronics and Telecommunications Research Institute). It is clear that 3-D TV broadcasting will be the next development in this field, and realistic broadcasting will soon follow.

  14. ADT-3D Tumor Detection Assistant in 3D

    Directory of Open Access Journals (Sweden)

    Jaime Lazcano Bello

    2008-12-01

    Full Text Available The present document describes ADT-3D (Three-Dimensional Tumor Detector Assistant, a prototype application developed to assist doctors diagnose, detect and locate tumors in the brain by using CT scan. The reader may find on this document an introduction to tumor detection; ADT-3D main goals; development details; description of the product; motivation for its development; result’s study; and areas of applicability.

  15. Unassisted 3D camera calibration

    Science.gov (United States)

    Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.

    2012-03-01

    With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.

  16. Handbook of 3D integration

    CERN Document Server

    Garrou , Philip; Ramm , Peter

    2014-01-01

    Edited by key figures in 3D integration and written by top authors from high-tech companies and renowned research institutions, this book covers the intricate details of 3D process technology.As such, the main focus is on silicon via formation, bonding and debonding, thinning, via reveal and backside processing, both from a technological and a materials science perspective. The last part of the book is concerned with assessing and enhancing the reliability of the 3D integrated devices, which is a prerequisite for the large-scale implementation of this emerging technology. Invaluable reading fo

  17. Tuotekehitysprojekti: 3D-tulostin

    OpenAIRE

    Pihlajamäki, Janne

    2011-01-01

    Opinnäytetyössä tutustuttiin 3D-tulostamisen teknologiaan. Työssä käytiin läpi 3D-tulostimesta tehty tuotekehitysprojekti. Sen lisäksi esiteltiin yleisellä tasolla tuotekehitysprosessi ja syntyneiden tulosten mahdollisia suojausmenetelmiä. Tavoitteena tässä työssä oli kehittää markkinoilta jo löytyvää kotitulostin-tasoista 3D-laiteteknologiaa lähemmäksi ammattilaistason ratkaisua. Tavoitteeseen pyrittiin keskittymällä parantamaan laitteella saavutettavaa tulostustarkkuutta ja -nopeutt...

  18. 3D on the internet

    OpenAIRE

    Puntar, Matej

    2012-01-01

    The purpose of this thesis is the presentation of already established and new technologies of displaying 3D content in a web browser. The thesis begins with a short presentation of the history of 3D content available on the internet and its development together with advantages and disadvantages of individual technologies. The latter two are described in detail as well is their use and the differences among them. Special emphasis has been given to WebGL, the newest technology of 3D conte...

  19. Color 3D Reverse Engineering

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper presents a principle and a method of col or 3D laser scanning measurement. Based on the fundamental monochrome 3D measureme nt study, color information capture, color texture mapping, coordinate computati on and other techniques are performed to achieve color 3D measurement. The syste m is designed and composed of a line laser light emitter, one color CCD camera, a motor-driven rotary filter, a circuit card and a computer. Two steps in captu ring object's images in the measurement process: Firs...

  20. Exploration of 3D Printing

    OpenAIRE

    Lin, Zeyu

    2014-01-01

    3D printing technology is introduced and defined in this Thesis. Some methods of 3D printing are illustrated and their principles are explained with pictures. Most of the essential parts are presented with pictures and their effects are explained within the whole system. Problems on Up! Plus 3D printer are solved and a DIY product is made with this machine. The processes of making product are recorded and the items which need to be noticed during the process are the highlight in this th...

  1. A New Method For Mitigation Of Cross Correlation In GPS Receiver

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>An algorithm for GPS receiver performing to mitigate cross correlations between weak satellite signal and strong satellite signals is presented.By using the tracking result of strong signal,the cross-correlation and cross correlation sequence between weak signals and strong signal can be computed,further modifying the local generate C/A code to drive the cross correlation to zero. The advantage of this method is that it does not require estimation of the strong signal amplitude and it partially independent of the data bit value.Simulation result shows it can eliminate the interference of 75%,and this method is at the cost of sensitivity loss of 0.28dB.

  2. Materialedreven 3d digital formgivning

    DEFF Research Database (Denmark)

    Hansen, Flemming Tvede

    2010-01-01

    traditionel keramisk produktionssammenhæng. Problemstillingen opmuntrede endvidere til i et samarbejde med en programmør at udvikle et 3d digitalt redskab, der er blevet kaldt et digitalt interaktivt formgivningsredskab (DIF). Eksperimentet undersøger interaktive 3d digitale dynamiske systemer, der...... samarbejder med designere fra fagområder som interaktionsdesign og programmering. Afhandlingen peger på et fremtidigt forskningsfelt indenfor generative og responderende digitale systemer til 3d formgivning, der ligeledes inkluderer følesansen. Endvidere er det relevant at forske i, hvordan de RP teknikker...... formgivning og Rapid Prototyping (RP). RP er en fællesbetegnelse for en række af de teknikker, der muliggør at overføre den digitale form til 3d fysisk form. Forskningsprojektet koncentrerer sig om to overordnede forskningsspørgsmål. Det første handler om, hvordan viden og erfaring indenfor det keramiske...

  3. On measuring surface wave phase velocity from station-station cross-correlation of ambient signal

    OpenAIRE

    Boschi, Lapo; Weemstra, Cornelis; Verbeke, Julie; Ekström, Göran; Zunino, Andrea; Giardini, Domenico

    2013-01-01

    International audience We apply two different algorithms to measure surface wave phase velocity, as a function of frequency, from seismic ambient noise recorded at pairs of stations from a large European network. The two methods are based on consistent theoretical formulations, but differ in the implementation: one method involves the time-domain cross-correlation of signal recorded at different stations; the other is based on frequency-domain cross-correlation, and requires finding the ze...

  4. Vector velocity estimation using directional beam forming and cross-correlation

    DEFF Research Database (Denmark)

    2000-01-01

    The two-dimensional velocity vector using a pulsed ultrasound field can be determined with the invention. The method uses a focused ultrasound field along the velocity direction for probing the moving medium under investigation. Several pulses are emitted and the focused received fields along...... the velocity direction are cross-correlated. The time shift between received signals is found from the peak in the cross-correlation function and the velocity is thereby determined....

  5. Multifractal Detrended Cross-Correlation Analysis for Large-Scale Warehouse-Out Behaviors

    Science.gov (United States)

    Yao, Can-Zhong; Lin, Ji-Nan; Zheng, Xu-Zhou

    2015-09-01

    Based on cross-correlation algorithm, we analyze the correlation property of warehouse-out quantity of different warehouses, respectively, and different products of each warehouse. Our study identifies that significant cross-correlation relationship for warehouse-out quantity exists among different warehouses and different products of a warehouse. Further, we take multifractal detrended cross-correlation analysis for warehouse-out quantity among different warehouses and different products of a warehouse. The results show that for the warehouse-out behaviors of total amount, different warehouses and different products of a warehouse significantly follow multifractal property. Specifically for each warehouse, the coupling relationships of rebar and wire rod reveal long-term memory characteristics, no matter for large fluctuation or small one. The cross-correlation effect on long-range memory property among warehouses probably has less to do with product types,and the long-term memory of YZ warehouse is greater than others especially in total amount and wire rod product. Finally, we shuffle and surrogate data to explore the source of multifractal cross-correlation property in logistics system. Taking the total amount of warehouse-out quantity as example, we confirm that the fat-tail distribution of warehouse-out quantity sequences is the main factor for multifractal cross-correlation. Through comparing the performance of the multifractal detrended cross-correlation analysis (MF-DCCA), centered multifractal detrending moving average cross-correlation analysis (MF-X-DMA) algorithms, the forward and backward MF-X-DMA algorithms, we find that the forward and backward MF-X-DMA algorithms exhibit a better performance than the other ones.

  6. Construction Zero Cross Correlation Code using Permutation Matrix for SAC-OCDMA Systems

    OpenAIRE

    Nisar, K. S.

    2016-01-01

    This paper present a new method for constructing zero cross correlation code with the help of permutation matrices. The benefits of this newly proposed code are easy way code construction, the code weight exist for every natural number and the code length is acceptable. The numerical comparison shows that the proposed code has better or compatible code length compared with other existing zero cross correlation code in Optical Spectrum Code Division Multiple Access (OSCDMA) systems.

  7. 3D Face Apperance Model

    DEFF Research Database (Denmark)

    Lading, Brian; Larsen, Rasmus; Astrom, K

    2006-01-01

    We build a 3D face shape model, including inter- and intra-shape variations, derive the analytical Jacobian of its resulting 2D rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations......We build a 3D face shape model, including inter- and intra-shape variations, derive the analytical Jacobian of its resulting 2D rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations...

  8. Main: TATCCAYMOTIFOSRAMY3D [PLACE

    Lifescience Database Archive (English)

    Full Text Available TATCCAYMOTIFOSRAMY3D S000256 01-August-2006 (last modified) kehi TATCCAY motif foun...d in rice (O.s.) RAmy3D alpha-amylase gene promoter; Y=T/C; a GATA motif as its antisense sequence; TATCCAY ...motif and G motif (see S000130) are responsible for sugar repression (Toyofuku et al. 1998); GATA; amylase; sugar; repression; rice (Oryza sativa) TATCCAY ...

  9. Combinatorial 3D Mechanical Metamaterials

    Science.gov (United States)

    Coulais, Corentin; Teomy, Eial; de Reus, Koen; Shokef, Yair; van Hecke, Martin

    2015-03-01

    We present a class of elastic structures which exhibit 3D-folding motion. Our structures consist of cubic lattices of anisotropic unit cells that can be tiled in a complex combinatorial fashion. We design and 3d-print this complex ordered mechanism, in which we combine elastic hinges and defects to tailor the mechanics of the material. Finally, we use this large design space to encode smart functionalities such as surface patterning and multistability.

  10. AI 3D Cybug Gaming

    CERN Document Server

    Ahmed, Zeeshan

    2010-01-01

    In this short paper I briefly discuss 3D war Game based on artificial intelligence concepts called AI WAR. Going in to the details, I present the importance of CAICL language and how this language is used in AI WAR. Moreover I also present a designed and implemented 3D War Cybug for AI WAR using CAICL and discus the implemented strategy to defeat its enemies during the game life.

  11. 3D Face Appearance Model

    DEFF Research Database (Denmark)

    Lading, Brian; Larsen, Rasmus; Åström, Kalle

    2006-01-01

    We build a 3d face shape model, including inter- and intra-shape variations, derive the analytical jacobian of its resulting 2d rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations.}......We build a 3d face shape model, including inter- and intra-shape variations, derive the analytical jacobian of its resulting 2d rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations.}...

  12. Pre-Processing and Cross-Correlation Techniques for Time-Distance Helioseismology

    Science.gov (United States)

    Wang, N.; de Ridder, S.; Zhao, J.

    2014-12-01

    In chaotic wave fields excited by a random distribution of noise sources a cross-correlation of the recordings made at two stations yield the interstation wave-field response. After early successes in helioseismology, laboratory studies and earth-seismology, this technique found broad application in global and regional seismology. This development came with an increasing understanding of pre-processing and cross-correlation workflows to yield an optimal signal-to-noise ratio (SNR). Helioseismologist rely heavily on stacking to increase the SNR. Until now, they have not studied different spectral-whitening and cross-correlation workflows and relies heavily on stacking to increase the SNR. The recordings vary considerably between sunspots and regular portions of the sun. Within the sunspot the periodic effects of the observation satellite orbit are difficult to remove. We remove a running alpha-mean from the data and apply a soft clip to deal with data glitches. The recordings contain energy of both flow and waves. A frequency domain filter selects the wave energy. Then the data is input to several pre-processing and cross-correlation techniques, common to earth seismology. We anticipate that spectral whitening will flatten the energy spectrum of the cross-correlations. We also expect that the cross-correlations converge faster to their expected value when the data is processed over overlapping windows. The result of this study are expected to aid in decreasing the stacking while maintaining good SNR.

  13. MPML3D: Scripting Agents for the 3D Internet.

    Science.gov (United States)

    Prendinger, Helmut; Ullrich, Sebastian; Nakasone, Arturo; Ishizuka, Mitsuru

    2011-05-01

    The aim of this paper is two-fold. First, it describes a scripting language for specifying communicative behavior and interaction of computer-controlled agents ("bots") in the popular three-dimensional (3D) multiuser online world of "Second Life" and the emerging "OpenSimulator" project. While tools for designing avatars and in-world objects in Second Life exist, technology for nonprogrammer content creators of scenarios involving scripted agents is currently missing. Therefore, we have implemented new client software that controls bots based on the Multimodal Presentation Markup Language 3D (MPML3D), a highly expressive XML-based scripting language for controlling the verbal and nonverbal behavior of interacting animated agents. Second, the paper compares Second Life and OpenSimulator platforms and discusses the merits and limitations of each from the perspective of agent control. Here, we also conducted a small study that compares the network performance of both platforms.

  14. From 3D view to 3D print

    Science.gov (United States)

    Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.

    2014-08-01

    In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers

  15. YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters

    Science.gov (United States)

    Schild, Jonas; Seele, Sven; Masuch, Maic

    2012-03-01

    Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.

  16. Remote 3D Medical Consultation

    Science.gov (United States)

    Welch, Greg; Sonnenwald, Diane H.; Fuchs, Henry; Cairns, Bruce; Mayer-Patel, Ketan; Yang, Ruigang; State, Andrei; Towles, Herman; Ilie, Adrian; Krishnan, Srinivas; Söderholm, Hanna M.

    Two-dimensional (2D) video-based telemedical consultation has been explored widely in the past 15-20 years. Two issues that seem to arise in most relevant case studies are the difficulty associated with obtaining the desired 2D camera views, and poor depth perception. To address these problems we are exploring the use of a small array of cameras to synthesize a spatially continuous range of dynamic three-dimensional (3D) views of a remote environment and events. The 3D views can be sent across wired or wireless networks to remote viewers with fixed displays or mobile devices such as a personal digital assistant (PDA). The viewpoints could be specified manually or automatically via user head or PDA tracking, giving the remote viewer virtual head- or hand-slaved (PDA-based) remote cameras for mono or stereo viewing. We call this idea remote 3D medical consultation (3DMC). In this article we motivate and explain the vision for 3D medical consultation; we describe the relevant computer vision/graphics, display, and networking research; we present a proof-of-concept prototype system; and we present some early experimental results supporting the general hypothesis that 3D remote medical consultation could offer benefits over conventional 2D televideo.

  17. Novel 3D media technologies

    CERN Document Server

    Dagiuklas, Tasos

    2015-01-01

    This book describes recent innovations in 3D media and technologies, with coverage of 3D media capturing, processing, encoding, and adaptation, networking aspects for 3D Media, and quality of user experience (QoE). The contributions are based on the results of the FP7 European Project ROMEO, which focuses on new methods for the compression and delivery of 3D multi-view video and spatial audio, as well as the optimization of networking and compression jointly across the future Internet. The delivery of 3D media to individual users remains a highly challenging problem due to the large amount of data involved, diverse network characteristics and user terminal requirements, as well as the user’s context such as their preferences and location. As the number of visual views increases, current systems will struggle to meet the demanding requirements in terms of delivery of consistent video quality to fixed and mobile users. ROMEO will present hybrid networking solutions that combine the DVB-T2 and DVB-NGH broadcas...

  18. 3D future internet media

    CERN Document Server

    Dagiuklas, Tasos

    2014-01-01

    This book describes recent innovations in 3D media and technologies, with coverage of 3D media capturing, processing, encoding, and adaptation, networking aspects for 3D Media, and quality of user experience (QoE). The main contributions are based on the results of the FP7 European Projects ROMEO, which focus on new methods for the compression and delivery of 3D multi-view video and spatial audio, as well as the optimization of networking and compression jointly across the Future Internet (www.ict-romeo.eu). The delivery of 3D media to individual users remains a highly challenging problem due to the large amount of data involved, diverse network characteristics and user terminal requirements, as well as the user’s context such as their preferences and location. As the number of visual views increases, current systems will struggle to meet the demanding requirements in terms of delivery of constant video quality to both fixed and mobile users. ROMEO will design and develop hybrid-networking solutions that co...

  19. 3D Imager and Method for 3D imaging

    NARCIS (Netherlands)

    Kumar, P.; Staszewski, R.; Charbon, E.

    2013-01-01

    3D imager comprising at least one pixel, each pixel comprising a photodetectorfor detecting photon incidence and a time-to-digital converter system configured for referencing said photon incidence to a reference clock, and further comprising a reference clock generator provided for generating the re

  20. Modification of 3D milling machine to 3D printer

    OpenAIRE

    Halamíček, Lukáš

    2015-01-01

    Tato práce se zabývá přestavbou gravírovací frézky na 3D tiskárnu. V první části se práce zabývá možnými technologiemi 3D tisku a možností jejich využití u přestavby. Dále jsou popsány a vybrány vhodné součásti pro přestavbu. V další části je realizováno řízení ohřevu podložky, trysky a řízení posuvu drátu pomocí softwaru TwinCat od společnosti Beckhoff na průmyslovém počítači. Výsledkem práce by měla být oživená 3D tiskárna. This thesis deals with rebuilding of engraving machine to 3D pri...

  1. Markerless 3D Face Tracking

    DEFF Research Database (Denmark)

    Walder, Christian; Breidt, Martin; Bulthoff, Heinrich;

    2009-01-01

    We present a novel algorithm for the markerless tracking of deforming surfaces such as faces. We acquire a sequence of 3D scans along with color images at 40Hz. The data is then represented by implicit surface and color functions, using a novel partition-of-unity type method of efficiently...... combining local regressors using nearest neighbor searches. Both these functions act on the 4D space of 3D plus time, and use temporal information to handle the noise in individual scans. After interactive registration of a template mesh to the first frame, it is then automatically deformed to track...... the scanned surface, using the variation of both shape and color as features in a dynamic energy minimization problem. Our prototype system yields high-quality animated 3D models in correspondence, at a rate of approximately twenty seconds per timestep. Tracking results for faces and other objects...

  2. Crowded Field 3D Spectroscopy

    CERN Document Server

    Becker, T; Roth, M M; Becker, Thomas; Fabrika, Sergei; Roth, Martin M.

    2003-01-01

    The quantitative spectroscopy of stellar objects in complex environments is mainly limited by the ability of separating the object from the background. Standard slit spectroscopy, restricting the field of view to one dimension, is obviously not the proper technique in general. The emerging Integral Field (3D) technique with spatially resolved spectra of a two-dimensional field of view provides a great potential for applying advanced subtraction methods. In this paper an image reconstruction algorithm to separate point sources and a smooth background is applied to 3D data. Several performance tests demonstrate the photometric quality of the method. The algorithm is applied to real 3D observations of a sample Planetary Nebula in M31, whose spectrum is contaminated by the bright and complex galaxy background. The ability of separating sources is also studied in a crowded stellar field in M33.

  3. 3D-grafiikkamoottori mobiililaitteille

    OpenAIRE

    Vahlman, Lauri

    2014-01-01

    Tässä insinöörityössä käydään läpi mobiililaitteille suunnatun yksinkertaisen 3D-grafiikkamoottorin suunnittelu ja toteutus käyttäen OpenGL ES -rajapintaa. Työssä esitellään grafiikkamoottorin toteutuksessa käytettyjä tekniikoita sekä tutustutaan moottorin rakenteeseen ja toteutuksellisiin yksityiskohtiin. Työn alkupuolella tutustutaan myös modernin 3D-grafiikan yleisiin periaatteisiin ja toimintaan sekä käydään läpi 3D-grafiikkaan liittyviä suorituskykyongelmia. Työn loppupuolella esitel...

  4. 3D vector flow imaging

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes

    The main purpose of this PhD project is to develop an ultrasonic method for 3D vector flow imaging. The motivation is to advance the field of velocity estimation in ultrasound, which plays an important role in the clinic. The velocity of blood has components in all three spatial dimensions, yet...... conventional methods can estimate only the axial component. Several approaches for 3D vector velocity estimation have been suggested, but none of these methods have so far produced convincing in vivo results nor have they been adopted by commercial manufacturers. The basis for this project is the Transverse...... on the TO fields are suggested. They can be used to optimize the TO method. In the third part, a TO method for 3D vector velocity estimation is proposed. It employs a 2D phased array transducer and decouples the velocity estimation into three velocity components, which are estimated simultaneously based on 5...

  5. Microfluidic 3D Helix Mixers

    Directory of Open Access Journals (Sweden)

    Georgette B. Salieb-Beugelaar

    2016-10-01

    Full Text Available Polymeric microfluidic systems are well suited for miniaturized devices with complex functionality, and rapid prototyping methods for 3D microfluidic structures are increasingly used. Mixing at the microscale and performing chemical reactions at the microscale are important applications of such systems and we therefore explored feasibility, mixing characteristics and the ability to control a chemical reaction in helical 3D channels produced by the emerging thread template method. Mixing at the microscale is challenging because channel size reduction for improving solute diffusion comes at the price of a reduced Reynolds number that induces a strictly laminar flow regime and abolishes turbulence that would be desired for improved mixing. Microfluidic 3D helix mixers were rapidly prototyped in polydimethylsiloxane (PDMS using low-surface energy polymeric threads, twisted to form 2-channel and 3-channel helices. Structure and flow characteristics were assessed experimentally by microscopy, hydraulic measurements and chromogenic reaction, and were modeled by computational fluid dynamics. We found that helical 3D microfluidic systems produced by thread templating allow rapid prototyping, can be used for mixing and for controlled chemical reaction with two or three reaction partners at the microscale. Compared to the conventional T-shaped microfluidic system used as a control device, enhanced mixing and faster chemical reaction was found to occur due to the combination of diffusive mixing in small channels and flow folding due to the 3D helix shape. Thus, microfluidic 3D helix mixers can be rapidly prototyped using the thread template method and are an attractive and competitive method for fluid mixing and chemical reactions at the microscale.

  6. Ideal 3D asymmetric concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Botella, Angel [Departamento Fisica Aplicada a los Recursos Naturales, Universidad Politecnica de Madrid, E.T.S.I. de Montes, Ciudad Universitaria s/n, 28040 Madrid (Spain); Fernandez-Balbuena, Antonio Alvarez; Vazquez, Daniel; Bernabeu, Eusebio [Departamento de Optica, Universidad Complutense de Madrid, Fac. CC. Fisicas, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2009-01-15

    Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used for producing reflective and refractive optical devices, including reverse engineering techniques. In this paper we apply photometric field theory and elliptic ray bundles method to study 3D asymmetric - without rotational or translational symmetry - concentrators, which can be useful components for nontracking solar applications. We study the one-sheet hyperbolic concentrator and we demonstrate its behaviour as ideal 3D asymmetric concentrator. (author)

  7. Advanced 3-D Ultrasound Imaging

    DEFF Research Database (Denmark)

    Rasmussen, Morten Fischer

    The main purpose of the PhD project was to develop methods that increase the 3-D ultrasound imaging quality available for the medical personnel in the clinic. Acquiring a 3-D volume gives the medical doctor the freedom to investigate the measured anatomy in any slice desirable after the scan has...... beamforming. This is achieved partly because synthetic aperture imaging removes the limitation of a fixed transmit focal depth and instead enables dynamic transmit focusing. Lately, the major ultrasound companies have produced ultrasound scanners using 2-D transducer arrays with enough transducer elements...

  8. Upper bound for the time derivative of entropy for a dynamical system driven by coloured cross-correlated white noises

    Institute of Scientific and Technical Information of China (English)

    Xie Wen-Xian; Xu Wei; Cai Li; Jin Yan-Fei

    2005-01-01

    It is shown how the cross-correlation time and strength of coloured cross-correlated white noises can set an upper bound for the time derivative of entropy in a nonequilibrium system. The value of upper bound can be calculateddirectly based on the Schwartz inequality principle and the Fokker-Planck equation of the dynamical system driven by coloured cross-correlated white noises. The present calculations can be used to interpret the interplay of the dissipative constant and cross-correlation time and strength of coloured cross-correlated white noises on the upper bound.

  9. PubChem3D: Biologically relevant 3-D similarity

    Directory of Open Access Journals (Sweden)

    Kim Sunghwan

    2011-07-01

    Full Text Available Abstract Background The use of 3-D similarity techniques in the analysis of biological data and virtual screening is pervasive, but what is a biologically meaningful 3-D similarity value? Can one find statistically significant separation between "active/active" and "active/inactive" spaces? These questions are explored using 734,486 biologically tested chemical structures, 1,389 biological assay data sets, and six different 3-D similarity types utilized by PubChem analysis tools. Results The similarity value distributions of 269.7 billion unique conformer pairs from 734,486 biologically tested compounds (all-against-all from PubChem were utilized to help work towards an answer to the question: what is a biologically meaningful 3-D similarity score? The average and standard deviation for the six similarity measures STST-opt, CTST-opt, ComboTST-opt, STCT-opt, CTCT-opt, and ComboTCT-opt were 0.54 ± 0.10, 0.07 ± 0.05, 0.62 ± 0.13, 0.41 ± 0.11, 0.18 ± 0.06, and 0.59 ± 0.14, respectively. Considering that this random distribution of biologically tested compounds was constructed using a single theoretical conformer per compound (the "default" conformer provided by PubChem, further study may be necessary using multiple diverse conformers per compound; however, given the breadth of the compound set, the single conformer per compound results may still apply to the case of multi-conformer per compound 3-D similarity value distributions. As such, this work is a critical step, covering a very wide corpus of chemical structures and biological assays, creating a statistical framework to build upon. The second part of this study explored the question of whether it was possible to realize a statistically meaningful 3-D similarity value separation between reputed biological assay "inactives" and "actives". Using the terminology of noninactive-noninactive (NN pairs and the noninactive-inactive (NI pairs to represent comparison of the "active/active" and

  10. DECONSTRUCTING THERMAL SUNYAEV–ZEL’DOVICH—GRAVITATIONAL LENSING CROSS-CORRELATIONS: IMPLICATIONS FOR THE INTRACLUSTER MEDIUM

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, N.; Hill, J. C. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Murray, N. [Canadian Institute for Theoretical Astrophysics, 60 St George, Toronto, ON M5S 3H8 (Canada)

    2015-10-20

    Recent first detections of the cross-correlation of the thermal Sunyaev–Zel’dovich (tSZ) signal in Planck cosmic microwave background (CMB) temperature maps with gravitational lensing maps inferred from the Planck CMB data and the CFHTLenS galaxy survey provide new probes of the relationship between baryons and dark matter. Using cosmological hydrodynamics simulations, we show that these cross-correlation signals are dominated by contributions from hot gas in the intracluster medium (ICM), rather than diffuse, unbound gas located beyond the virial radius (the “missing baryons”). Thus, these cross-correlations offer a tool with which to study the ICM over a wide range of halo masses and redshifts. In particular, we show that the tSZ—CMB lensing cross-correlation is more sensitive to gas in lower-mass, higher-redshift halos and gas at larger cluster-centric radii than the tSZ—galaxy lensing cross-correlation. Combining these measurements with primary CMB data will constrain feedback models through their signatures in the ICM pressure profile. We forecast the ability of ongoing and future experiments to constrain the parameters of a phenomenological ICM model, including the mean amplitude of the pressure–mass relation, the redshift evolution of this amplitude, and the mean outer logarithmic slope of the pressure profile. The results are promising, with ≈5%–20% precision constraints achievable with upcoming experiments, even after marginalizing over cosmological parameters.

  11. Cross-correlations between West Texas Intermediate crude oil and the stock markets of the BRIC

    Science.gov (United States)

    Ma, Feng; Wei, Yu; Huang, Dengshi; Zhao, Lin

    2013-11-01

    In this paper, we investigate the cross-correlation properties between West Texas Intermediate crude oil and the stock markets of the BRIC. We use not only the qualitative analysis of the cross-correlation test, but also take the quantitative analysis of the MF-DXA, confirming the cross-correlation relationship between West Texas Intermediate crude oil and the stock markets of the BRIC (Brazil, Russia, India and China) respectively, which have strongly multifractal features, and the cross-correlations are more strongly multifractal in the short term than in the long term. Furthermore, based on the multifractal spectrum, we also find the multifractality strength between the crude oil WTI and Chinese stock market is stronger than the multifractality strength of other pairs. Based on the Iraq war (Mar 20, 2003) and the Financial crisis in 2008, we divide sample period into four segments to research the degree of the multifractal (ΔH) and the market efficiency (and the risk). Finally, we employ the technique of the rolling window to calculate the time-varying EI (efficiency index) and dependent on the EI, we can easily observe the change of stock markets. Furthermore, we explore the relationship between bivariate cross-correlation exponents (Hxy(q)) and the generalized Hurst exponents.

  12. Long-range cross-correlation between urban impervious surfaces and land surface temperatures

    Institute of Scientific and Technical Information of China (English)

    Qin NIE; Jianhua XU; Wang MAN

    2016-01-01

    The thermal effect of urban impervious surfaces (UIS) is a complex problem.It is thus necessary to study the relationship between UIS and land surface temperatures (LST) using complexity science theory and methods.This paper investigates the long-range cross-correlation between UIS and LST with detrended cross-correlation analysis and multifractal detrended cross-correlation analysis,utilizing data from downtown Shanghai,China.UIS estimates were obtained from linear spectral mixture analysis,and LST was retrieved through application of the mono-window algorithm,using Landsat Thematic Mapper and Enhanced Thematic Mapper Plus data for 1997-2010.These results highlight a positive long-range cross-correlation between UIS and LST across People's Square in Shanghai.LST has a long memory for a certain spatial range of UIS values,such that a large increment in UIS is likely to be followed by a large increment in LST.While the multifractal long-range cross-correlation between UIS and LST was observed over a longer time period in the W-E direction (2002-2010) than in the N-S (2007-2010),these observed correlations show a weakening during the study period as urbanization increased.

  13. Long-range cross-correlation between urban impervious surfaces and land surface temperatures

    Science.gov (United States)

    Nie, Qin; Xu, Jianhua; Man, Wang

    2016-03-01

    The thermal effect of urban impervious surfaces (UIS) is a complex problem. It is thus necessary to study the relationship between UIS and land surface temperatures (LST) using complexity science theory and methods. This paper investigates the long-range cross-correlation between UIS and LST with detrended cross-correlation analysis and multifractal detrended cross-correlation analysis, utilizing data from downtown Shanghai, China. UIS estimates were obtained from linear spectral mixture analysis, and LST was retrieved through application of the mono-window algorithm, using Landsat Thematic Mapper and Enhanced Thematic Mapper Plus data for 1997-2010. These results highlight a positive long-range cross-correlation between UIS and LST across People's Square in Shanghai. LST has a long memory for a certain spatial range of UIS values, such that a large increment in UIS is likely to be followed by a large increment in LST. While the multifractal long-range cross-correlation between UIS and LST was observed over a longer time period in the W-E direction (2002-2010) than in the N-S (2007-2010), these observed correlations show a weakening during the study period as urbanization increased.

  14. Detrended fluctuation analysis made flexible to detect range of cross-correlated fluctuations

    CERN Document Server

    Kwapien, Jaroslaw; Drozdz, Stanislaw

    2015-01-01

    The detrended cross-correlation coefficient $\\rho_{\\rm DCCA}$ has recently been proposed to quantify the strength of cross-correlations on different temporal scales in bivariate, non-stationary time series. It is based on the detrended cross-correlation and detrended fluctuation analyses (DCCA and DFA, respectively) and can be viewed as an analogue of the Pearson coefficient in the case of the fluctuation analysis. The coefficient $\\rho_{\\rm DCCA}$ works well in many practical situations but by construction its applicability is limited to detection of whether two signals are generally cross-correlated, without possibility to obtain information on the amplitude of fluctuations that are responsible for those cross-correlations. In order to introduce some related flexibility, here we propose an extension of $\\rho_{\\rm DCCA}$ that exploits the multifractal versions of DFA and DCCA: MFDFA and MFCCA, respectively. The resulting new coefficient $\\rho_q$ not only is able to quantify the strength of correlations, but ...

  15. 3D Face Apperance Model

    OpenAIRE

    Lading, Brian; Larsen, Rasmus; Astrom, K

    2006-01-01

    We build a 3D face shape model, including inter- and intra-shape variations, derive the analytical Jacobian of its resulting 2D rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations

  16. 3D Face Appearance Model

    OpenAIRE

    Lading, Brian; Larsen, Rasmus; Åström, Kalle

    2006-01-01

    We build a 3d face shape model, including inter- and intra-shape variations, derive the analytical jacobian of its resulting 2d rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations.}

  17. Making Inexpensive 3-D Models

    Science.gov (United States)

    Manos, Harry

    2016-01-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…

  18. When Art Meets 3D

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The presentation of the vanguard work,My Dream3D,the innovative production by the China Disabled People’s Performing Art Troupe(CDPPAT),directed by Joy Joosang Park,provided the film’s domestic premiere at Beijing’s Olympic Park onApril7.The show provided an intriguing insight not

  19. 3D terahertz beam profiling

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Strikwerda, Andrew; Wang, Tianwu;

    2013-01-01

    We present a characterization of THz beams generated in both a two-color air plasma and in a LiNbO3 crystal. Using a commercial THz camera, we record intensity images as a function of distance through the beam waist, from which we extract 2D beam profiles and visualize our measurements into 3D beam...

  20. 3D Printing: Exploring Capabilities

    Science.gov (United States)

    Samuels, Kyle; Flowers, Jim

    2015-01-01

    As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…

  1. Viewing galaxies in 3D

    CERN Document Server

    Krajnović, Davor

    2016-01-01

    Thanks to a technique that reveals galaxies in 3D, astronomers can now show that many galaxies have been wrongly classified. Davor Krajnovi\\'c argues that the classification scheme proposed 85 years ago by Edwin Hubble now needs to be revised.

  2. 3D reconstruction of tropospheric cirrus clouds by stereovision system

    Science.gov (United States)

    Nadjib Kouahla, Mohamed; Moreels, Guy; Seridi, Hamid

    2016-07-01

    A stereo imaging method is applied to measure the altitude of cirrus clouds and provide a 3D map of the altitude of the layer centroid. They are located in the high troposphere and, sometimes in the lower stratosphere, between 6 and 10 km high. Two simultaneous images of the same scene are taken with Canon cameras (400D) in two sites distant of 37 Km. Each image processed in order to invert the perspective effect and provide a satellite-type view of the layer. Pairs of matched points that correspond to a physical emissive point in the common area are identified in calculating a correlation coefficient (ZNCC: Zero mean Normalized Cross-correlation or ZSSD: as Zero mean Sum of Squared Differences). This method is suitable for obtaining 3D representations in the case of low-contrast objects. An observational campaign was conducted in June 2014 in France. The images were taken simultaneously at Marnay (47°17'31.5" N, 5°44'58.8" E; altitude 275 m) 25 km northwest of Besancon and in Mont poupet (46°58'31.5" N, 5°52'22.7" E; altitude 600 m) southwest of Besancon at 43 km. 3D maps of the Natural cirrus clouds and artificial like "aircraft trails" are retrieved. They are compared with pseudo-relief intensity maps of the same region. The mean altitude of the cirrus barycenter is located at 8.5 ± 1km on June 11.

  3. Priprava 3D modelov za 3D tisk

    OpenAIRE

    Pikovnik, Tomaž

    2015-01-01

    Po mnenju nekaterih strokovnjakov bo aditivna proizvodnja (ali 3D tiskanje) spremenila proizvodnjo industrijo, saj si bo vsak posameznik lahko natisnil svoj objekt po želji. V diplomski nalogi so predstavljene nekatere tehnologije aditivne proizvodnje. V nadaljevanju diplomske naloge je predstavljena izdelava makete hiše v merilu 1:100, vse od modeliranja do tiskanja. Poseben poudarek je posvečen predelavi modela, da je primeren za tiskanje, kjer je razvit pristop za hitrejše i...

  4. Post processing of 3D models for 3D printing

    OpenAIRE

    Pikovnik, Tomaž

    2015-01-01

    According to the opinion of some experts the additive manufacturing or 3D printing will change manufacturing industry, because any individual could print their own model according to his or her wishes. In this graduation thesis some of the additive manufacturing technologies are presented. Furthermore in the production of house scale model in 1:100 is presented, starting from modeling to printing. Special attention is given to postprocessing of the building model elements us...

  5. 3D Cameras: 3D Computer Vision of Wide Scope

    OpenAIRE

    May, Stefan; Pervoelz, Kai; Surmann, Hartmut

    2007-01-01

    First of all, a short comparison of range sensors and their underlying principles was given. The chapter further focused on 3D cameras. The latest innovations have given a significant improvement for the measurement accuracy, wherefore this technology has attracted attention in the robotics community. This was also the motivation for the examination in this chapter. On this account, several applications were presented, which represents common problems in the domain of autonomous robotics. For...

  6. DYNA3D2000*, Explicit 3-D Hydrodynamic FEM Program

    International Nuclear Information System (INIS)

    1 - Description of program or function: DYNA3D2000 is a nonlinear explicit finite element code for analyzing 3-D structures and solid continuum. The code is vectorized and available on several computer platforms. The element library includes continuum, shell, beam, truss and spring/damper elements to allow maximum flexibility in modeling physical problems. Many materials are available to represent a wide range of material behavior, including elasticity, plasticity, composites, thermal effects and rate dependence. In addition, DYNA3D has a sophisticated contact interface capability, including frictional sliding, single surface contact and automatic contact generation. 2 - Method of solution: Discretization of a continuous model transforms partial differential equations into algebraic equations. A numerical solution is then obtained by solving these algebraic equations through a direct time marching scheme. 3 - Restrictions on the complexity of the problem: Recent software improvements have eliminated most of the user identified limitations with dynamic memory allocation and a very large format description that has pushed potential problem sizes beyond the reach of most users. The dominant restrictions remain in code execution speed and robustness, which the developers constantly strive to improve

  7. Multifractal detrended cross-correlation analysis of genome sequences using chaos-game representation

    Science.gov (United States)

    Pal, Mayukha; Kiran, V. Satya; Rao, P. Madhusudana; Manimaran, P.

    2016-08-01

    We characterized the multifractal nature and power law cross-correlation between any pair of genome sequence through an integrative approach combining 2D multifractal detrended cross-correlation analysis and chaos game representation. In this paper, we have analyzed genomes of some prokaryotes and calculated fractal spectra h(q) and f(α) . From our analysis, we observed existence of multifractal nature and power law cross-correlation behavior between any pair of genome sequences. Cluster analysis was performed on the calculated scaling exponents to identify the class affiliation and the same is represented as a dendrogram. We suggest this approach may find applications in next generation sequence analysis, big data analytics etc.

  8. One-factor model for the cross-correlation matrix in the Vietnamese stock market

    Science.gov (United States)

    Nguyen, Quang

    2013-07-01

    Random matrix theory (RMT) has been applied to the analysis of the cross-correlation matrix of a financial time series. The most important findings of previous studies using this method are that the eigenvalue spectrum largely follows that of random matrices but the largest eigenvalue is at least one order of magnitude higher than the maximum eigenvalue predicted by RMT. In this work, we investigate the cross-correlation matrix in the Vietnamese stock market using RMT and find similar results to those of studies realized in developed markets (US, Europe, Japan) [9-18] as well as in other emerging markets[20,21,19,22]. Importantly, we found that the largest eigenvalue could be approximated by the product of the average cross-correlation coefficient and the number of stocks studied. We demonstrate this dependence using a simple one-factor model. The model could be extended to describe other characteristics of the realistic data.

  9. Baryon acoustic oscillations with the cross-correlation of spectroscopic and photometric samples

    CERN Document Server

    Nishizawa, Atsushi J; Takada, Masahiro

    2013-01-01

    The baryon acoustic oscillation (BAO) experiment requires a sufficiently dense sampling of large-scale structure tracers with spectroscopic redshift, which is observationally expensive especially at high redshifts $z\\simgt 1$. Here we present an alternative route of the BAO analysis that uses the cross-correlation of sparse spectroscopic tracers with a much denser photometric sample, where the spectroscopic tracers can be quasars or bright, rare galaxies that are easier to access spectroscopically. We show that measurements of the cross-correlation as a function of the transverse comoving separation rather than the angular separation avoid a smearing of the BAO feature without mixing the different scales at different redshifts in the projection, even for a wide redshift slice $\\Delta z\\simeq 1$. The bias, scatter, and catastrophic redshift errors of the photometric sample affect only the overall normalization of the cross-correlation which can be marginalized over when constraining the angular diameter distan...

  10. Needlet estimation of cross-correlation between CMB lensing maps and LSS

    CERN Document Server

    Bianchini, Federico; Marinucci, Domenico

    2016-01-01

    In this paper we develop a novel needlet-based estimator to investigate the cross-correlation between cosmic microwave background (CMB) lensing maps and large-scale structure (LSS) data. We compare this estimator with its harmonic counterpart and, in particular, we analyze the bias effects of different forms of masking. In order to address this bias, we also implement a MASTER-like technique in the needlet case. The resulting estimator turns out to have an extremely good signal-to-noise performance. Our analysis aims at expanding and optimizing the operating domains in CMB-LSS cross-correlation studies, similarly to CMB needlet data analysis. It is motivated especially by next generation experiments (such as Euclid) which will allow us to derive much tighter constraints on cosmological and astrophysical parameters through cross-correlation measurements between CMB and LSS.

  11. Cross-Correlation Earthquake Precursors in the Hydrogeochemical and Geoacoustic Signals for the Kamchatka Peninsula

    CERN Document Server

    Ryabinin, G V; Polyakov, Yu S; Timashev, S F

    2012-01-01

    We propose a new type of earthquake precursor based on the analysis of correlation dynamics between geophysical signals of different nature. The precursor is found using a two-parameter cross-correlation function introduced within the framework of flicker-noise spectroscopy, a general statistical physics approach to the analysis of time series. We consider an example of cross-correlation analysis for water salinity time series, an integral characteristic of the chemical composition of groundwater, and geoacoustic emissions recorded at the G-1 borehole on the Kamchatka peninsula in the time frame from 2001 to 2003, which is characterized by a sequence of three groups of significant seismic events. We found that cross-correlation precursors took place 27, 31, and 35 days ahead of the strongest earthquakes for each group of seismic events, respectively. At the same time, precursory anomalies in the signals themselves were observed only in the geoacoustic emissions for one group of earthquakes.

  12. MEASURING SEA ICE DRIFT VIA CROSS-CORRELATION OF RADAR ICE IMAGES

    Institute of Scientific and Technical Information of China (English)

    SUN He-quan; SHEN Yong-ming; Qiu Da-hong

    2004-01-01

    The motion of sea ice has a great effect on winter navigation, and oil field exploration in the Bohai Sea. It is very important to measure the ice drift accurately and efficiently. As a practical technique, radar imagery has been used for sea ice monitoring and forecasting for a long time. Combining with the radar imagery and cross-correlation technique, a new measurement method based on the cross-correlation of radar ice images is specified in this paper to obtain full field measurement of sea ice drift. The theory and fast implementation of cross-correlation are presented briefly in the paper, including the filtering method to modify the invalid vectors. To show deeply the validity of the present method, the velocity maps of sea ice drift are provided in the paper, which are calculated from the radar images grabbed in the Liaodong Gulf. The comparison with the traditional tracing method is also conducted.

  13. Velocity Distribution Measurement Using Pixel-Pixel Cross Correlation of Electrical Tomography

    Institute of Scientific and Technical Information of China (English)

    DENGXiang; PENGLihui; YAODanya; ZHANGBaofen

    2004-01-01

    Electrical tomography (ET) provides a novel means of visualizing the internal behavior of twophase flow in industrial process. Using a dual-sensingplane Electrical resistance tomography (ERT) or Electrical capacitance tomography (ECT) system, the raw data of two different section images can be acquired synchronously and the two images reflecting the inner medium distribution respectively can also be reconstructed by using imaging algorithm. Further, the analysis of pixel-pixel cross correlation is able to be setup and the measurement of velocity distribution of two-phase flow could be achieved. The principle is described in the paper. The FFT algorithm for gray value computation and cross correlation function calculation is also introduced. Some experimental results of velocity distribution measurement using pixelpixel cross correlation in vertical slug flow are presented.

  14. Effects of Cross-Correlation Colour Noises on Tumour Growth Process

    Institute of Scientific and Technical Information of China (English)

    WANG Xian-Ju; ZENG Chang-Chun; DENG Xiao-Yuan; LIU Song-Hao; LIU Liang-Gang

    2005-01-01

    @@ We present a tumour cell growth process model including a multiplicative coloured noise and an additive coloured noise correlated. How the noise cross-correlation intensity λ and correlation time - can affect the steady state properties of tumour cell growth model are discussed by solving an approximative Fokker-Planck equation. It is found that the increase of noise correlation time т- can cause the tumour cell number increasing, but the increase of multiplicative noise intensity can cause the tumour cell number extinction. We also find that the increase of cross-correlation intensity λ in the case of 0 <λ< 1 can cause the tumour cell number extinction, whereas increase of cross-correlation intensity λ in the case of λ< 0 can cause the tumour cell number increasing.

  15. Error analysis in cross-correlation of sky maps: application to the ISW detection

    CERN Document Server

    Cabre, A; Manera, E G M; Cabre, Anna; Fosalba, Pablo; Manera, Enrique Gaztanaga & Marc

    2007-01-01

    Constraining cosmological parameters from measurements of the Integrated Sachs-Wolfe effect requires developing robust and accurate methods for computing statistical errors in the cross-correlation between maps. This paper presents a detailed comparison of such error estimation applied to the case of cross-correlation of Cosmic Microwave Background (CMB) and large-scale structure data. We compare theoretical models for error estimation with montecarlo simulations where both the galaxy and the CMB maps vary around a fiducial auto-correlation and cross-correlation model which agrees well with the current concordance LCDM cosmology. Our analysis compares estimators both in harmonic and configuration (or real) space, quantifies the accuracy of the error analysis and discuss the impact of partial sky survey area and the choice of input fiducial model on dark-energy constraints. We show that purely analytic approaches yield accurate errors even in surveys that cover only 10% of the sky and that parameter constraint...

  16. Are Eurozone Fixed Income Markets Integrated? An Analysis Based on Wavelet Multiple Correlation and Cross Correlation

    Directory of Open Access Journals (Sweden)

    Arif Billah Dar

    2014-01-01

    Full Text Available This paper investigates the synchronization of fixed income markets within Eurozone countries using the new wavelet based methodology. Conventional wavelet methods that use multivariate set of variables to calculate pairwise correlation and cross correlation lead to spurious correlation due to possible relationships with other variables, amplification of type-1 errors, and results, in the form of large set of erroneous graphs. Given these disadvantages of conventional wavelet based pairwise correlation and cross-correlation method, we avoid these limitations by using wavelet multiple correlation and multiple cross correlations to analyze the relationships in Eurozone fixed income markets. Our results based on this methodology indicate that Eurozone fixed income markets are highly integrated and this integration grows with timescales, and hence there is almost no scope for independent monetary policy and bond diversification in these countries.

  17. Cross-correlation analysis of stock markets using EMD and EEMD

    Science.gov (United States)

    Xu, Mengjia; Shang, Pengjian; Lin, Aijing

    2016-01-01

    Empirical mode decomposition (EMD) is a data-driven signal analysis method for nonlinear and nonstationary data. Since it is intuitive, direct, posterior and adaptive, EMD is widely applied to various fields of study. In this paper, EMD and ensemble empirical mode decomposition (EEMD), a modified method of EMD, are applied to financial time series. Through analyzing the intrinsic mode functions (IMFs) of EMD and EEMD, we find EEMD method performs better on the orthogonality of IMFs than EMD. With clustering the ordered frequencies of IMFs, the IMFs obtained from EEMD method are grouped into high-, medium-, and low-frequency components, representing the short-, medium-, and long-term volatilities of the index sequences, respectively. With the cross-correlation analysis of DCCA cross-correlation coefficient, our findings allow us to gain further and detailed insight into the cross-correlations of stock markets.

  18. Detrended fluctuation analysis made flexible to detect range of cross-correlated fluctuations

    Science.gov (United States)

    Kwapień, Jarosław; Oświecimka, Paweł; DroŻdŻ, Stanisław

    2015-11-01

    The detrended cross-correlation coefficient ρDCCA has recently been proposed to quantify the strength of cross-correlations on different temporal scales in bivariate, nonstationary time series. It is based on the detrended cross-correlation and detrended fluctuation analyses (DCCA and DFA, respectively) and can be viewed as an analog of the Pearson coefficient in the case of the fluctuation analysis. The coefficient ρDCCA works well in many practical situations but by construction its applicability is limited to detection of whether two signals are generally cross-correlated, without the possibility to obtain information on the amplitude of fluctuations that are responsible for those cross-correlations. In order to introduce some related flexibility, here we propose an extension of ρDCCA that exploits the multifractal versions of DFA and DCCA: multifractal detrended fluctuation analysis and multifractal detrended cross-correlation analysis, respectively. The resulting new coefficient ρq not only is able to quantify the strength of correlations but also allows one to identify the range of detrended fluctuation amplitudes that are correlated in two signals under study. We show how the coefficient ρq works in practical situations by applying it to stochastic time series representing processes with long memory: autoregressive and multiplicative ones. Such processes are often used to model signals recorded from complex systems and complex physical phenomena like turbulence, so we are convinced that this new measure can successfully be applied in time-series analysis. In particular, we present an example of such application to highly complex empirical data from financial markets. The present formulation can straightforwardly be extended to multivariate data in terms of the q -dependent counterpart of the correlation matrices and then to the network representation.

  19. AN IMPROVED CROSS-CORRELATION METHOD FOR (DIGITAL) PARTICLE IMAGE VELOCIMETRY

    Institute of Scientific and Technical Information of China (English)

    翁文国; 范维澄; 廖光煊; 秦俊

    2001-01-01

    An improved method that brings enhancement in accuracy for the interrogation of (digital) PIV images is described in this paper. This method is based on cross-correlation with discrete window offset, which makes use of a translation of the second interrogation window and rebuilds it considering rotation and shear.The displacement extracted from PIV images is predicted and corrected by means of an iterative procedure. In addition, the displacement vectors are validated at each intermediate of the iteration process. The present improved cross-correlation method is compared with the conventional one in accuracy by interrogation of synthetic and real (digital) PIV images and the interrogation results are discussed.

  20. Precise optical modeling for LED lighting verified by cross correlation in the midfield region.

    Science.gov (United States)

    Sun, Ching-Cherng; Lee, Tsung-Xian; Ma, Shih-Hsin; Lee, Ya-Luan; Huang, Shih-Ming

    2006-07-15

    A novel LED modeling algorithm for precise three-dimensional light pattern simulation is proposed and demonstrated. We propose to use normalized cross correlation to verify the validity of the simulation in one-dimensional intensity patterns as well as two-dimensional irradiance patterns in various midfield distances and to provide feedback to achieve a successful model. The model is demonstrated to obtain an average of 99% in normalized cross correlation between the simulation light pattern and experimental measurement for a truncated inverse pyramid LED.

  1. Seismicity of the North Atlantic as measured by the International Data Centre using waveform cross correlation

    Science.gov (United States)

    Kitov, Ivan; Bobrov, Dmitry; Rozhkov, Mikhail

    2013-04-01

    The Technical Secretariat (TS) of the Comprehensive Nuclear Test-Ban Treaty Organization (CTBTO) will carry out the verification of the CTBT which obligates each State Party not to carry out nuclear explosions. The International Data Centre (IDC) receives, collects, processes, analyses, reports on and archives data from the International Monitoring System. The IDC is responsible for automatic and interactive processing of the International Monitoring System (IMS) data and for standard IDC products. The IDC is also required by the Treaty to progressively enhance its technical capabilities. In this study, we use waveform cross correlation as a technique to improve the detection capability and reliability of the seismic part of the IMS. In order to quantitatively estimate the gain obtained by cross correlation on the current sensitivity of automatic and interactive processing we compared seismic bulletins built for the North Atlantic (NA), which is a seismically isolated region with earthquakes concentrating around the Mid-Atlantic Ridge. This allows avoiding the spill-over of mislocated events between adjacent seismic regions and biases in the final bulletins: the Reviewed Event Bulletin (REB) issued by the IDC and the cross correlation Standard Event List (XSEL). To begin with, we cross correlated waveforms recorded at 18 IMS array stations from ~1500 events reported in the REB between 2009 and 2011. The resulting cross correlation matrix revealed the best candidates for master events. We have selected 60 master events evenly distributed over the seismically active zone in the NA. High-quality signals (SNR>5.0) recorded by 10 most sensitive array stations were used as waveform templates. These templates are used for a continuous calculation of cross correlation coefficients in the first half of 2012. All detections obtained by cross-correlation are then used to build events according to the current IDC definition: at least three primary stations with accurate

  2. Theoretical basis of non-intrusive ultrasonic cross correlation flow measurement technology

    International Nuclear Information System (INIS)

    The non-intrusive ultrasonic cross correlation flow meter CROSSFLOW, developed and manufactured by Advanced Measurement and Analysis Group Inc. (AMAG) is installed in nuclear reactors in Canada and around the world. AMAG and De Montfort University (UK) are cooperating in an ongoing research project to develop a theoretical basis for cross correlation flow measurement technology, with the goal of improving measurement accuracy. The project involves theoretical development, laboratory testing, and computational flow simulations. This paper describes the recent progress of this project. (author)

  3. Influence of cross correlations on interdiffusion in Al-rich Al-Ni melts

    Science.gov (United States)

    Sondermann, Elke; Kargl, Florian; Meyer, Andreas

    2016-05-01

    The relation of self- and interdiffusion in a liquid metal, particularly the influence of cross correlations at low concentrations, is studied experimentally. Accurate interdiffusion data are obtained by a combination of x-ray radiography with the shear-cell method on the ground and on the sounding rocket MAPHEUS under microgravity conditions. Self-diffusion coefficients, measured by quasielastic neutron scattering, increase with decreasing Ni concentration, whereas interdiffusion coefficients are about constant. We show that cross correlations influence interdiffusion even at concentrations as low as 2 at. % Ni. Consequently, Darken's equation is not valid in this case.

  4. The Virgo - MiniGRAIL cross correlation for the detection of scalar gravitational waves

    OpenAIRE

    Corda, Christian

    2007-01-01

    After a review of the frequency - dependent angular pattern of interferometers in the TT gauge for scalar gravitational waves (SGWs), which has been recently analysed by Capozziello and Corda, in this letter the result is used to study the cross correlation between the Virgo interferometer and the MiniGRAIL resonant sphere. It is shown that the overlap reduction function for the cross correlation bewteen Virgo and the monopole mode of MiniGRAIL is very small, but a maximum is also found in th...

  5. Tentative Detection of Quasar Feedback from WMAP and SDSS Cross-Correlation

    OpenAIRE

    Chatterjee, Suchetana; Ho, Shirley; Newman, Jeffrey A.; Kosowsky, Arthur

    2009-01-01

    We perform a cross-correlation analysis of microwave data from Wilkinson Microwave Anisotropy Probe and photometric quasars from the Sloan Digital Sky Survey, testing for Sunyaev-Zeldovich (SZ) effect from quasars. A statistically significant (2.5 $\\sigma$) temperature decrement exists in the 41 GHz microwave band. A two-component fit to the cross-correlation spectrum incorporating both dust emission and SZ yields a best-fit $y$ parameter of $(7.0 \\pm 3.4)\\times 10^{-7}$. A similar cross-corr...

  6. 3D Printable Graphene Composite.

    Science.gov (United States)

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-07-08

    In human being's history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today's personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite's linear thermal coefficient is below 75 ppm·°C(-1) from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.

  7. 3-D Relativistic MHD Simulations

    Science.gov (United States)

    Nishikawa, K.-I.; Frank, J.; Koide, S.; Sakai, J.-I.; Christodoulou, D. M.; Sol, H.; Mutel, R. L.

    1998-12-01

    We present 3-D numerical simulations of moderately hot, supersonic jets propagating initially along or obliquely to the field lines of a denser magnetized background medium with Lorentz factors of W = 4.56 and evolving in a four-dimensional spacetime. The new results are understood as follows: Relativistic simulations have consistently shown that these jets are effectively heavy and so they do not suffer substantial momentum losses and are not decelerated as efficiently as their nonrelativistic counterparts. In addition, the ambient magnetic field, however strong, can be pushed aside with relative ease by the beam, provided that the degrees of freedom associated with all three spatial dimensions are followed self-consistently in the simulations. This effect is analogous to pushing Japanese ``noren'' or vertical Venetian blinds out of the way while the slats are allowed to bend in 3-D space rather than as a 2-D slab structure.

  8. 3D Printed Robotic Hand

    Science.gov (United States)

    Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.

    2013-01-01

    Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.

  9. Forensic 3D Scene Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.

    1999-10-12

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  10. [Real time 3D echocardiography

    Science.gov (United States)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  11. NMR cross-correlated relaxation rates reveal ion coordination sites in DNA

    NARCIS (Netherlands)

    Fiala, R.; Spackova, N.; Foldynová-Trantírková, S.; Sponer, J.; Sklenár, V.; Trantirek, L.

    2011-01-01

    In this work, a novel NMR method for the identification of preferential coordination sites between physiologically relevant counterions and nucleic acid bases is demonstrated. In this approach, the NMR cross-correlated relaxation rates between the aromatic carbon chemical shift anisotropy and the pr

  12. Statistical properties of cross-correlation in the Korean stock market

    Science.gov (United States)

    Oh, G.; Eom, C.; Wang, F.; Jung, W.-S.; Stanley, H. E.; Kim, S.

    2011-01-01

    We investigate the statistical properties of the cross-correlation matrix between individual stocks traded in the Korean stock market using the random matrix theory (RMT) and observe how these affect the portfolio weights in the Markowitz portfolio theory. We find that the distribution of the cross-correlation matrix is positively skewed and changes over time. We find that the eigenvalue distribution of original cross-correlation matrix deviates from the eigenvalues predicted by the RMT, and the largest eigenvalue is 52 times larger than the maximum value among the eigenvalues predicted by the RMT. The β_{473} coefficient, which reflect the largest eigenvalue property, is 0.8, while one of the eigenvalues in the RMT is approximately zero. Notably, we show that the entropy function E(σ) with the portfolio risk σ for the original and filtered cross-correlation matrices are consistent with a power-law function, E( σ) σ^{-γ}, with the exponent γ 2.92 and those for Asian currency crisis decreases significantly.

  13. Detectability of the 21-cm CMB cross-correlation from the epoch of reionization

    NARCIS (Netherlands)

    Tashiro, Hiroyuki; Aghanim, Nabila; Langer, Mathieu; Douspis, Marian; Zaroubi, Saleem; Jelic, Vibor

    2010-01-01

    The 21-cm line fluctuations and the cosmic microwave background (CMB) are powerful probes of the epoch of reionization of the Universe. We study the potential of the cross-correlation between 21-cm line fluctuations and CMB anisotropy to obtain further constraints on the reionization history. We ana

  14. Retrieving electric resistivity data from self-potential measurements by cross-correlation

    NARCIS (Netherlands)

    Slob, E.C.; Snieder, R.; Revil, A.

    2010-01-01

    We show that the two-point cross-correlation of self-potential field recordings is equal to the electric resistivity between the two points. This holds under the condition that spatially and temporally uncorrelated noise sources exist throughout the volume. These sources should have a known amplitud

  15. Lenses in the forest: cross--correlation of the Lyman-alpha flux with CMB lensing

    Energy Technology Data Exchange (ETDEWEB)

    Vallinotto, Alberto; /Paris, Inst. Astrophys. /Fermilab; Das, Sudeep; /Princeton U. Observ. /Princeton U.; Spergel, David N.; /Princeton U. Observ. /APC, Paris; Viel, Matteo; /Trieste Observ. /INFN, Trieste

    2009-03-01

    We present a theoretical estimate for a new observable: the cross-correlation between the Lyman-{alpha}-flux fluctuations in quasar (QSO) spectra and the convergence of the cosmic microwave background (CMB) as measured along the same line-of-sight. As a first step toward the assessment of its detectability, we estimate the signal-to-noise ratio using linear theory. Although the signal-to-noise is small for a single line-of-sight and peaks at somewhat smaller redshifts than those probed by the Lyman-{alpha} forest, we estimate a total signal-to-noise of 9 for cross-correlating QSO spectra of SDSSIII with Planck and 20 for cross-correlating with a future polarization based CMB experiment. The detection of this effect would be a direct measure of the neutral hydrogen-matter cross-correlation and could provide important information on the growth of structures at large scales in a redshift range which is still poorly probed by observations.

  16. Cross-correlation between X-ray and optical/near-infrared background intensity fluctuations

    CERN Document Server

    Mitchell-Wynne, Ketron; Xue, Yongquan; Luo, Bin; Brandt, William; Koekemoer, Anton

    2016-01-01

    Angular power spectra of optical and infrared background anisotropies at wavelengths between 0.5 to 5 $\\mu$m are a useful probe of faint sources present during reionization, in addition to faint galaxies and diffuse signals at low redshift. The cross-correlation of these fluctuations with backgrounds at other wavelengths can be used to separate some of these signals. A previous study on the cross-correlation between X-ray and $Spitzer$ fluctuations at 3.6 $\\mu$m and 4.5 $\\mu$m has been interpreted as evidence for direct collapse blackholes (DCBHs) present at $z > 12$. Here we return to this cross-correlation and study its wavelength dependence from 0.5 to 4.5 $\\mu$m using $Hubble$ and $Spitzer$ data in combination with a subset of the 4 Ms $Chandra$ observations in GOODS-S/ECDFS. Our study involves five $Hubble$ bands at 0.6, 0.7, 0.85, 1.25 and 1.6 $\\mu$m, and two $Spitzer$-IRAC bands at 3.6 $\\mu$m and 4.5 $\\mu$m. We confirm the previously seen cross-correlation between 3.6 $\\mu$m (4.5 $\\mu$m) and X-rays wit...

  17. Cross-correlations between 21 cm,X-ray and infrared backgrounds

    Institute of Scientific and Technical Information of China (English)

    Huan-Yuan Shan; Bo Qin

    2009-01-01

    The history of the cosmological reionization is still unclear. Two ionizing sources, stars and QSOs, are believed to play important roles during this epoch. Besides the 21 cm signals, the infrared emission from Pop Ⅲ stars and X-ray photons from QSOs can be powerful probes of the reionization. Here we present a cross-correlation study of the 21 cm, infrared and X-ray backgrounds. The advantage of doing such cross-correlations is that we could highlight the correlated signals and eliminate irrelevant fore-grounds. We develop a shell model to describe the 21 cm signals and find that PopⅢ stars can provide higher 21 cm signals than QSOs. Using the ROSAT data for X-ray and AKARI data for infrared, we predict various cross power spectra analytically and dis-cuss prospects for detecting these cross-correlation signals in future low frequency radio surveys. We find that, although these cross-correlational signals have distinct features, so far, they have been difficult to detect due to the high noise of the soft X-ray and infrared backgrounds given by ROSAT and AKARI.

  18. Dose fractionation theorem in 3-D reconstruction (tomography)

    Energy Technology Data Exchange (ETDEWEB)

    Glaeser, R.M. [Lawrence Berkeley National Lab., CA (United States)

    1997-02-01

    It is commonly assumed that the large number of projections for single-axis tomography precludes its application to most beam-labile specimens. However, Hegerl and Hoppe have pointed out that the total dose required to achieve statistical significance for each voxel of a computed 3-D reconstruction is the same as that required to obtain a single 2-D image of that isolated voxel, at the same level of statistical significance. Thus a statistically significant 3-D image can be computed from statistically insignificant projections, as along as the total dosage that is distributed among these projections is high enough that it would have resulted in a statistically significant projection, if applied to only one image. We have tested this critical theorem by simulating the tomographic reconstruction of a realistic 3-D model created from an electron micrograph. The simulations verify the basic conclusions of high absorption, signal-dependent noise, varying specimen contrast and missing angular range. Furthermore, the simulations demonstrate that individual projections in the series of fractionated-dose images can be aligned by cross-correlation because they contain significant information derived from the summation of features from different depths in the structure. This latter information is generally not useful for structural interpretation prior to 3-D reconstruction, owing to the complexity of most specimens investigated by single-axis tomography. These results, in combination with dose estimates for imaging single voxels and measurements of radiation damage in the electron microscope, demonstrate that it is feasible to use single-axis tomography with soft X-ray microscopy of frozen-hydrated specimens.

  19. Wireless 3D Chocolate Printer

    Directory of Open Access Journals (Sweden)

    FROILAN G. DESTREZA

    2014-02-01

    Full Text Available This study is for the BSHRM Students of Batangas State University (BatStateU ARASOF for the researchers believe that the Wireless 3D Chocolate Printer would be helpful in their degree program especially on making creative, artistic, personalized and decorative chocolate designs. The researchers used the Prototyping model as procedural method for the successful development and implementation of the hardware and software. This method has five phases which are the following: quick plan, quick design, prototype construction, delivery and feedback and communication. This study was evaluated by the BSHRM Students and the assessment of the respondents regarding the software and hardware application are all excellent in terms of Accuracy, Effecitveness, Efficiency, Maintainability, Reliability and User-friendliness. Also, the overall level of acceptability of the design project as evaluated by the respondents is excellent. With regard to the observation about the best raw material to use in 3D printing, the chocolate is good to use as the printed material is slightly distorted,durable and very easy to prepare; the icing is also good to use as the printed material is not distorted and is very durable but consumes time to prepare; the flour is not good as the printed material is distorted, not durable but it is easy to prepare. The computation of the economic viability level of 3d printer with reference to ROI is 37.14%. The recommendation of the researchers in the design project are as follows: adding a cooling system so that the raw material will be more durable, development of a more simplified version and improving the extrusion process wherein the user do not need to stop the printing process just to replace the empty syringe with a new one.

  20. INGRID, 3-D Mesh Generator for Program DYNA3D and NIKE3D and FACET and TOPAZ3D

    International Nuclear Information System (INIS)

    1 - Description of program or function: INGRID is a general-purpose, three-dimensional mesh generator developed for use with finite element, nonlinear, structural dynamics codes. INGRID generates the large and complex input data files for DYNA3D (NESC 9909), NIKE3D (NESC 9725), FACET, and TOPAZ3D. One of the greatest advantages of INGRID is that virtually any shape can be described without resorting to wedge elements, tetrahedrons, triangular elements or highly distorted quadrilateral or hexahedral elements. Other capabilities available are in the areas of geometry and graphics. Exact surface equations and surface intersections considerably improve the ability to deal with accurate models, and a hidden line graphics algorithm is included which is efficient on the most complicated meshes. The most important new capability is associated with the boundary conditions, loads, and material properties required by nonlinear mechanics programs. Commands have been designed for each case to minimize user effort. This is particularly important since special processing is almost always required for each load or boundary condition. 2 - Method of solution: Geometries are described primarily using the index space notation of the INGEN program (NESC 975) with an additional type of notation, index progression. Index progressions provide a concise and simple method for describing complex structures; the concept was developed to facilitate defining multiple regions in index space. Rather than specifying the minimum and maximum indices for a region, one specifies the progression of indices along the I, J and K directions, respectively. The index progression method allows the analyst to describe most geometries including nodes and elements with roughly the same amount of input as a solids modeler

  1. Body Waves Revealed by Spatial Stacking on Long-Term Cross-Correlation of Ambient Noise

    Institute of Scientific and Technical Information of China (English)

    Kai Wang; Yinhe Luo; Kaifeng Zhao; Limeng Zhang

    2014-01-01

    ABSTRCT: Theoretical and experimental studies indicate that complete Green’s Function can be retrieved from cross-correlation in a diffuse field. High SNR (signal-to-noise ratio) surface waves have been extracted from cross-correlations of long-duration ambient noise across the globe. Body waves, not extracted in most of ambient noise studies, are thought to be more difficult to retrieve from regular ambient noise data processing. By stacking cross-correlations of ambient noise in 50 km inter-station distance bins in China, western United States and Europe, we observed coherent 20–100 s core phases (ScS, PKIKPPKIKP, PcPPKPPKP) and crustal-mantle phases (Pn, P, PL, Sn, S, SPL, SnSn, SS, SSPL) at distances ranging from 0 to 4 000 km. Our results show that these crustal-mantle phases show diverse characteristics due to different substructure and sources of body waves beneath different regions while the core phases are relatively robust and can be retrieved as long as stations are available. Further analysis indicates that the SNR of these body-wave phases depends on a compromise between stacking fold in spatial domain and the coherence of pre-stacked cross-correlations.Spatially stacked cross-correlations of seismic noise can provide new virtual seismograms for paths that complement earthquake data and that contain valuable information on the structure of the Earth. The extracted crustal-mantle phases can be used to study lithospheric heterogeneities and the robust core phases are significantly useful to study the deep structure of the Earth, such as detecting fine heterogeneities of the core-mantle boundary and constraining differential rotation of the inner core.

  2. Estimating error cross-correlations in soil moisture data sets using extended collocation analysis

    Science.gov (United States)

    Gruber, A.; Su, C.-H.; Crow, W. T.; Zwieback, S.; Dorigo, W. A.; Wagner, W.

    2016-02-01

    Global soil moisture records are essential for studying the role of hydrologic processes within the larger earth system. Various studies have shown the benefit of assimilating satellite-based soil moisture data into water balance models or merging multisource soil moisture retrievals into a unified data set. However, this requires an appropriate parameterization of the error structures of the underlying data sets. While triple collocation (TC) analysis has been widely recognized as a powerful tool for estimating random error variances of coarse-resolution soil moisture data sets, the estimation of error cross covariances remains an unresolved challenge. Here we propose a method—referred to as extended collocation (EC) analysis—for estimating error cross-correlations by generalizing the TC method to an arbitrary number of data sets and relaxing the therein made assumption of zero error cross-correlation for certain data set combinations. A synthetic experiment shows that EC analysis is able to reliably recover true error cross-correlation levels. Applied to real soil moisture retrievals from Advanced Microwave Scanning Radiometer-EOS (AMSR-E) C-band and X-band observations together with advanced scatterometer (ASCAT) retrievals, modeled data from Global Land Data Assimilation System (GLDAS)-Noah and in situ measurements drawn from the International Soil Moisture Network, EC yields reasonable and strong nonzero error cross-correlations between the two AMSR-E products. Against expectation, nonzero error cross-correlations are also found between ASCAT and AMSR-E. We conclude that the proposed EC method represents an important step toward a fully parameterized error covariance matrix for coarse-resolution soil moisture data sets, which is vital for any rigorous data assimilation framework or data merging scheme.

  3. Intensity mapping cross-correlations: connecting the largest scales to galaxy evolution

    Science.gov (United States)

    Wolz, L.; Tonini, C.; Blake, C.; Wyithe, J. S. B.

    2016-05-01

    Intensity mapping of the neutral hydrogen (H I) is a new observational tool to efficiently map the large-scale structure over wide redshift ranges. The cross-correlation of intensity maps with galaxy surveys is a robust measure of the cosmological power spectrum and the H I content of galaxies which diminishes systematics caused by instrumental effects and foreground removal. We examine the cross-correlation signature at redshift 0.9 using a semi-analytical galaxy formation model in order to model the H I gas of galaxies as well as their optical magnitudes. We determine the scale-dependent clustering of the cross-correlation power for different types of galaxies determined by their colours, which act as a proxy for their star formation activity. We find that the cross-correlation coefficient with H I density for red quiescent galaxies falls off more quickly on smaller scales k > 0.2 h Mpc-1 than for blue star-forming galaxies. Additionally, we create a mock catalogue of highly star-forming galaxies to mimic the WiggleZ Dark Energy Survey, and use this to predict existing and future measurements using data from the Green Bank telescope and Parkes telescope. We find that the cross-power of highly star-forming galaxies shows a higher clustering on small scales than any other galaxy type and that this significantly alters the power spectrum shape on scales k > 0.2 h Mpc-1. We show that the cross-correlation coefficient is not negligible when interpreting the cosmological cross-power spectrum and additionally contains information about the H I content of the optically selected galaxies.

  4. Multi-component based cross correlation beat detection in electrocardiogram analysis

    Directory of Open Access Journals (Sweden)

    Owens Frank J

    2004-07-01

    Full Text Available Abstract Background The first stage in computerised processing of the electrocardiogram is beat detection. This involves identifying all cardiac cycles and locating the position of the beginning and end of each of the identifiable waveform components. The accuracy at which beat detection is performed has significant impact on the overall classification performance, hence efforts are still being made to improve this process. Methods A new beat detection approach is proposed based on the fundamentals of cross correlation and compared with two benchmarking approaches of non-syntactic and cross correlation beat detection. The new approach can be considered to be a multi-component based variant of traditional cross correlation where each of the individual inter-wave components are sought in isolation as opposed to being sought in one complete process. Each of three techniques were compared based on their performance in detecting the P wave, QRS complex and T wave in addition to onset and offset markers for 3000 cardiac cycles. Results Results indicated that the approach of multi-component based cross correlation exceeded the performance of the two benchmarking techniques by firstly correctly detecting more cardiac cycles and secondly provided the most accurate marker insertion in 7 out of the 8 categories tested. Conclusion The main benefit of the multi-component based cross correlation algorithm is seen to be firstly its ability to successfully detect cardiac cycles and secondly the accurate insertion of the beat markers based on pre-defined values as opposed to performing individual gradient searches for wave onsets and offsets following fiducial point location.

  5. Tehokas 3D-animaatiotuotanto

    OpenAIRE

    Järvinen, Manu

    2009-01-01

    Opinnäytetyössä tutkittiin tehokasta tapaa toteuttaa minuutin mittainen animaatio Scene.org Awards -tapahtuman avajaisseremoniaan. Kyseinen video toteutettiin osana opinnäytetyötä. Työhön osallistui tekijän lisäksi 3D-mallintaja sekä muusikko. Työkaluina käytettiin pääasiassa Autodesk 3ds Max-, sekä Adobe After Effects- ja Adobe Photoshop -ohjelmia. Opinnäytetyö koostuu animaatioprojektin tuotantoputken ja tiedostonhallintamallin perinpohjaisesta läpikäymisestä sekä sen asian tutkimisesta...

  6. Virtual 3-D Facial Reconstruction

    Directory of Open Access Journals (Sweden)

    Martin Paul Evison

    2000-06-01

    Full Text Available Facial reconstructions in archaeology allow empathy with people who lived in the past and enjoy considerable popularity with the public. It is a common misconception that facial reconstruction will produce an exact likeness; a resemblance is the best that can be hoped for. Research at Sheffield University is aimed at the development of a computer system for facial reconstruction that will be accurate, rapid, repeatable, accessible and flexible. This research is described and prototypical 3-D facial reconstructions are presented. Interpolation models simulating obesity, ageing and ethnic affiliation are also described. Some strengths and weaknesses in the models, and their potential for application in archaeology are discussed.

  7. Making Inexpensive 3-D Models

    Science.gov (United States)

    Manos, Harry

    2016-03-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the TPT theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity well tailored to specific class lessons. Most of the supplies are readily available in the home or at school: rubbing alcohol, a rag, two colors of spray paint, art brushes, and masking tape. The cost of these supplies, if you don't have them, is less than 20.

  8. How 3-D Movies Work

    Institute of Scientific and Technical Information of China (English)

    吕铁雄

    2011-01-01

    难度:★★★★☆词数:450 建议阅读时间:8分钟 Most people see out of two eyes. This is a basic fact of humanity,but it’s what makes possible the illusion of depth(纵深幻觉) that 3-D movies create. Human eyes are spaced about two inches apart, meaning that each eye gives the brain a slightly different perspective(透视感)on the same object. The brain then uses this variance to quickly determine an object’s distance.

  9. Positional Awareness Map 3D (PAM3D)

    Science.gov (United States)

    Hoffman, Monica; Allen, Earl L.; Yount, John W.; Norcross, April Louise

    2012-01-01

    The Western Aeronautical Test Range of the National Aeronautics and Space Administration s Dryden Flight Research Center needed to address the aging software and hardware of its current situational awareness display application, the Global Real-Time Interactive Map (GRIM). GRIM was initially developed in the late 1980s and executes on older PC architectures using a Linux operating system that is no longer supported. Additionally, the software is difficult to maintain due to its complexity and loss of developer knowledge. It was decided that a replacement application must be developed or acquired in the near future. The replacement must provide the functionality of the original system, the ability to monitor test flight vehicles in real-time, and add improvements such as high resolution imagery and true 3-dimensional capability. This paper will discuss the process of determining the best approach to replace GRIM, and the functionality and capabilities of the first release of the Positional Awareness Map 3D.

  10. 3D Printable Graphene Composite

    Science.gov (United States)

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-07-01

    In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C-1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.

  11. 3D printed bionic ears.

    Science.gov (United States)

    Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

    2013-06-12

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

  12. 3D printed bionic ears.

    Science.gov (United States)

    Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

    2013-06-12

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.

  13. 2D-3D rigid registration to compensate for prostate motion during 3D TRUS-guided biopsy

    Science.gov (United States)

    De Silva, Tharindu; Fenster, Aaron; Bax, Jeffrey; Gardi, Lori; Romagnoli, Cesare; Samarabandu, Jagath; Ward, Aaron D.

    2012-02-01

    Prostate biopsy is the clinical standard for prostate cancer diagnosis. To improve the accuracy of targeting suspicious locations, systems have been developed that can plan and record biopsy locations in a 3D TRUS image acquired at the beginning of the procedure. Some systems are designed for maximum compatibility with existing ultrasound equipment and are thus designed around the use of a conventional 2D TRUS probe, using controlled axial rotation of this probe to acquire a 3D TRUS reference image at the start of the biopsy procedure. Prostate motion during the biopsy procedure causes misalignments between the prostate in the live 2D TRUS images and the pre-acquired 3D TRUS image. We present an image-based rigid registration technique that aligns live 2D TRUS images, acquired immediately prior to biopsy needle insertion, with the pre-acquired 3D TRUS image to compensate for this motion. Our method was validated using 33 manually identified intrinsic fiducials in eight subjects and the target registration error was found to be 1.89 mm. We analysed the suitability of two image similarity metrics (normalized cross correlation and mutual information) for this task by plotting these metrics as a function of varying parameters in the six degree-of-freedom transformation space, with the ground truth plane obtained from registration as the starting point for the parameter exploration. We observed a generally convex behaviour of the similarity metrics. This encourages their use for this registration problem, and could assist in the design of a tool for the detection of misalignment, which could trigger the execution of a non-real-time registration, when needed during the procedure.

  14. LOTT RANCH 3D PROJECT

    International Nuclear Information System (INIS)

    The Lott Ranch 3D seismic prospect located in Garza County, Texas is a project initiated in September of 1991 by the J.M. Huber Corp., a petroleum exploration and production company. By today's standards the 126 square mile project does not seem monumental, however at the time it was conceived it was the most intensive land 3D project ever attempted. Acquisition began in September of 1991 utilizing GEO-SEISMIC, INC., a seismic data contractor. The field parameters were selected by J.M. Huber, and were of a radical design. The recording instruments used were GeoCor IV amplifiers designed by Geosystems Inc., which record the data in signed bit format. It would not have been practical, if not impossible, to have processed the entire raw volume with the tools available at that time. The end result was a dataset that was thought to have little utility due to difficulties in processing the field data. In 1997, Yates Energy Corp. located in Roswell, New Mexico, formed a partnership to further develop the project. Through discussions and meetings with Pinnacle Seismic, it was determined that the original Lott Ranch 3D volume could be vastly improved upon reprocessing. Pinnacle Seismic had shown the viability of improving field-summed signed bit data on smaller 2D and 3D projects. Yates contracted Pinnacle Seismic Ltd. to perform the reprocessing. This project was initiated with high resolution being a priority. Much of the potential resolution was lost through the initial summing of the field data. Modern computers that are now being utilized have tremendous speed and storage capacities that were cost prohibitive when this data was initially processed. Software updates and capabilities offer a variety of quality control and statics resolution, which are pertinent to the Lott Ranch project. The reprocessing effort was very successful. The resulting processed data-set was then interpreted using modern PC-based interpretation and mapping software. Production data, log data

  15. 3D Printing of Graphene Aerogels.

    Science.gov (United States)

    Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong

    2016-04-01

    3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (aerogel presents superelastic and high electrical conduction. PMID:26861680

  16. 3D biometrics systems and applications

    CERN Document Server

    Zhang, David

    2013-01-01

    Includes discussions on popular 3D imaging technologies, combines them with biometric applications, and then presents real 3D biometric systems Introduces many efficient 3D feature extraction, matching, and fusion algorithms Techniques presented have been supported by experimental results using various 3D biometric classifications

  17. Using cross-correlation to map the Transition Zone thickness beneath the Iberian Peninsula and Morocco

    Science.gov (United States)

    Bonatto, L.; Schimmel, M.; Gallart, J.; Morales, J.

    2012-12-01

    Upper mantle discontinuities are commonly studied through the detection of waves which have been converted/reflected at these discontinuities. In this work a novel processing approach which is leaned on receiver functions and which is based on cross-correlation and stacking techniques was implemented to search for weak amplitude upper mantle phases that arrive in the P-wave coda, such as P-to-s conversions. To add consistency and robustness to the detections, the new approach has been used together with receiver functions. This, also permits to bridge observation gaps due to break down of one of the techniques inherent to data characteristics. The aim of this work is to map the limits of the Transition Zone, which are the 410-km and 660-km depth discontinuities, beneath the Iberian Peninsula and north Africa. The new processing approach uses two independent cross-correlations (phase cross-correlation and cross-correlation geometrically normalized) and stacking techniques (phase weighted stack) in order to eliminate the source influence and to enhance coherent signals detected for the different events at individual stations. A pilot wavelet is selected from the vertical component, this wavelet contains the P phase and part of its coda with the later arriving depth phases. Converted and reflected phases are then detected by the cross-correlation of this pilot with the vertical and radial component of each recorded event, and the stacking of cross-correlograms for common conversion point areas. Cross-correlation provides relative travel times with respect to the P phase through its correlation maxima, and stacking enhances the signals which arrive consistently (near receiver conversions and reflections) and attenuates isolated depth phases such as near source reverberations and spurious arrivals. Slant stacks are used to correctly identify these coda signals. The described process was performed for teleseismic earthquakes registered in the seismic network of Topo

  18. 3D Printing of Graphene Aerogels.

    Science.gov (United States)

    Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong

    2016-04-01

    3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction.

  19. Photopolymers in 3D printing applications

    OpenAIRE

    Pandey, Ramji

    2014-01-01

    3D printing is an emerging technology with applications in several areas. The flexibility of the 3D printing system to use variety of materials and create any object makes it an attractive technology. Photopolymers are one of the materials used in 3D printing with potential to make products with better properties. Due to numerous applications of photopolymers and 3D printing technologies, this thesis is written to provide information about the various 3D printing technologies with particul...

  20. Natural fibre composites for 3D Printing

    OpenAIRE

    Pandey, Kapil

    2015-01-01

    3D printing has been common option for prototyping. Not all the materials are suitable for 3D printing. Various studies have been done and still many are ongoing regarding the suitability of the materials for 3D printing. This thesis work discloses the possibility of 3D printing of certain polymer composite materials. The main objective of this thesis work was to study the possibility for 3D printing the polymer composite material composed of natural fibre composite and various different ...

  1. Conducting polymer 3D microelectrodes

    DEFF Research Database (Denmark)

    Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi;

    2010-01-01

    Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained...... showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared...... with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described...

  2. 3D Energy Harvester Evaluation

    Directory of Open Access Journals (Sweden)

    V. Janicek

    2013-04-01

    Full Text Available This paper discusses the characterization and evaluation of an MEMS based electrostatic generator, a part of the power supply unit of the self-powered microsystem[1,2,3]. The designed generator is based on electrostatic converter and uses the principle of conversion of non-electric energy into electrical energy by periodical modification of gap between electrodes of a capacitor [4]. The structure is designed and modeled as three-dimensional silicon based MEMS. Innovative approach involving the achievement of very low resonant frequency of the structure (about 100Hz by usage of modified long cantilever spring design, minimum area of the chip, 3D work mode, the ability to be tuned to reach desired parameters, proves promising directions of possible further development.

  3. Conducting Polymer 3D Microelectrodes

    Directory of Open Access Journals (Sweden)

    Jenny Emnéus

    2010-12-01

    Full Text Available Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements.

  4. Supernova Remnant in 3-D

    Science.gov (United States)

    2009-01-01

    of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through. The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave. This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron. High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these structures, but their orientation and

  5. Spatially varying cross-correlation coefficients in the presence of nugget effects

    KAUST Repository

    Kleiber, William

    2012-11-29

    We derive sufficient conditions for the cross-correlation coefficient of a multivariate spatial process to vary with location when the spatial model is augmented with nugget effects. The derived class is valid for any choice of covariance functions, and yields substantial flexibility between multiple processes. The key is to identify the cross-correlation coefficient matrix with a contraction matrix, which can be either diagonal, implying a parsimonious formulation, or a fully general contraction matrix, yielding greater flexibility but added model complexity. We illustrate the approach with a bivariate minimum and maximum temperature dataset in Colorado, allowing the two variables to be positively correlated at low elevations and nearly independent at high elevations, while still yielding a positive definite covariance matrix. © 2012 Biometrika Trust.

  6. Time Evolution of Financial Cross-Correlation Coefficients across Market Crisis

    Science.gov (United States)

    Tacchella, Andrea; Cristelli, Matthieu; Zaccaria, Andrea; Pietronero, Luciano

    We investigate the time evolution of financial cross-correlation coefficients during financial crises and compare them to what is observed in periods of stability. We choose three main events, the Dot.Com Bubble, the market crisis which followed the attacks at the Twin Towers in 2001 and the recent subprime crisis. Each of them has a different nature and a different impact on the market, which we analyze by studying separately different economic sectors. As a general trend, we observe an increase of correlation during these high volatility periods and a broadening of the distributions of correlation coefficients. We then compare the spectra of the cross-correlation matrices, calculated in different periods of three years, with the distribution of eigenvalues predicted by the Random Matrix Theory. We find that these spectra are markedly perturbated during crisis periods. Finally we show how a simple stochastic model can produce similar results.

  7. The study of recent seismicity in the aftershock area of Neftegorsk earthquake using waveform cross correlation

    Science.gov (United States)

    Kitov, Ivan; Turuntaev, Sergey; Konovalov, Alexei; Stepnov, Andrey

    2016-04-01

    Unusually long duration of seismic activity (more than 20 years) was observed in the aftershock area of the 1995 Neftegorsk, Sakhalin, Russia catastrophic earthquake (Ms=7.6). To study the phenomena, we have processed seismic data from 130 events occurred within that area as measured between 2006 and 2015. In order to improve the accuracy of relative location and magnitude estimation of these events we have applied new techniques based on waveform cross correlation. We use 7 three-component (3-C) seismic stations which detected most of these events. Three-component waveform templates were prepared for these stations from those events which had signals with SNR>5 at vertical channels. The events with 3 and more templates are used as master-events for waveform cross correlation. Overall, the re-estimated location and magnitudes demonstrate higher precisions and are used for the statistical analysis and numerical modelling of seismo-tectonic regime within the studied zone.

  8. A new detrended semipartial cross-correlation analysis: Assessing the important meteorological factors affecting API

    Science.gov (United States)

    Shen, Chen-Hua

    2015-12-01

    To analyze the unique contribution of meteorological factors to the air pollution index (API), a new method, the detrended semipartial cross-correlation analysis (DSPCCA), is proposed. Based on both a detrended cross-correlation analysis and a DFA-based multivariate-linear-regression (DMLR), this method is improved by including a semipartial correlation technique, which is used to indicate the unique contribution of an explanatory variable to multiple correlation coefficients. The advantages of this method in handling nonstationary time series are illustrated by numerical tests. To further demonstrate the utility of this method in environmental systems, new evidence of the primary contribution of meteorological factors to API is provided through DMLR. Results show that the most important meteorological factors affecting API are wind speed and diurnal temperature range, and the explanatory ability of meteorological factors to API gradually strengthens with increasing time scales. The results suggest that DSPCCA is a useful method for addressing environmental systems.

  9. Novel Point-to-Point Scan Matching Algorithm Based on Cross-Correlation

    Directory of Open Access Journals (Sweden)

    Jaromir Konecny

    2016-01-01

    Full Text Available The localization of mobile robots in outdoor and indoor environments is a complex issue. Many sophisticated approaches, based on various types of sensory inputs and different computational concepts, are used to accomplish this task. However, many of the most efficient methods for mobile robot localization suffer from high computational costs and/or the need for high resolution sensory inputs. Scan cross-correlation is a traditional approach that can be, in special cases, used to match temporally aligned scans of robot environment. This work proposes a set of novel modifications to the cross-correlation method that extend its capability beyond these special cases to general scan matching and mitigate its computational costs so that it is usable in practical settings. The properties and validity of the proposed approach are in this study illustrated on a number of computational experiments.

  10. Optimal cosmic microwave background map-making in the presence of cross-correlated noise

    Science.gov (United States)

    de Gasperis, G.; Buzzelli, A.; Cabella, P.; de Bernardis, P.; Vittorio, N.

    2016-08-01

    Aims: We present an extension of the ROMA map-making algorithm for the generation of optimal cosmic microwave background polarization maps. The new code allows for a possible cross-correlated noise component among the detectors of a CMB experiment. A promising application is the forthcoming LSPE balloon-borne experiment, which is devoted to the accurate observation of CMB polarization at large angular scales. Methods: We generalized the noise covariance matrix in time domain to account for all the off-diagonal terms due to the detector cross-talk. Hence, we performed preliminary forecasts of the LSPE-SWIPE instrument. Results: We found that considering the noise cross-correlation among the detectors results in a more realistic estimate of the angular power spectra. In particular, the extended ROMA algorithm has provided a considerable reduction of the spectra error bars. We expect that this improvement could be crucial in constraining the B-mode polarization at the largest scales.

  11. Interpreting Cross-correlations of One-bit Filtered Seismic Noise

    CERN Document Server

    Hanasoge, Shravan

    2013-01-01

    Seismic noise, generated by oceanic microseisms and other sources, illuminates the crust in a manner different from tectonic sources, and therefore provides independent information. The primary measurable is the two-point cross-correlation, evaluated using traces recorded at a pair of seismometers over a finite-time interval. However, raw seismic traces contain intermittent large-amplitude perturbations arising from tectonic activity and instrumental errors, which may corrupt the estimated cross-correlations of microseismic fluctuations. In order to diminish the impact of these perturbations, the recorded traces are filtered using the nonlinear one-bit digitizer, which replaces the measurement by its sign. Previous theory shows that for stationary Gaussian-distributed seismic noise fluctuations one-bit and raw correlation functions are related by a simple invertible transformation. Here we extend this to show that the simple correspondence between these two correlation techniques remains valid for {\\it non-st...

  12. Dynamical Analysis of Stock Market Instability by Cross-correlation Matrix

    Science.gov (United States)

    Takaishi, Tetsuya

    2016-08-01

    We study stock market instability by using cross-correlations constructed from the return time series of 366 stocks traded on the Tokyo Stock Exchange from January 5, 1998 to December 30, 2013. To investigate the dynamical evolution of the cross-correlations, crosscorrelation matrices are calculated with a rolling window of 400 days. To quantify the volatile market stages where the potential risk is high, we apply the principal components analysis and measure the cumulative risk fraction (CRF), which is the system variance associated with the first few principal components. From the CRF, we detected three volatile market stages corresponding to the bankruptcy of Lehman Brothers, the 2011 Tohoku Region Pacific Coast Earthquake, and the FRB QE3 reduction observation in the study period. We further apply the random matrix theory for the risk analysis and find that the first eigenvector is more equally de-localized when the market is volatile.

  13. Cross-correlation Based Synchronization Mechanism of LDDoS Attacks

    Directory of Open Access Journals (Sweden)

    Zhijun WU

    2014-03-01

    Full Text Available A success Low-rate Distributed Denial of Service (LDDoS attack is composed of many single sources of Low-rate Denial of Service (LDoS attacks, which are well-organized in time synchronization to aggregate the attack flow at the end of target router. This paper addresses time synchronization and flow aggregation in LDDoS attacks for the purpose of exploring the attack performance. A cross-correlation algorithm is proposed to guarantee all network-wide distributed attack pulses aggregate at the victim end with a strict time limitation to form a powerful attack pulse. Experiments on the attack performance of LDoS and LDDoS attack are performed in NS-2 simulation platform. Experiment results show that the LDDoS attack effects can be improved significantly by using cross-correlation algorithm to coordinate attack pulses, which obtain better attack performance than many single dependent attack pulses. 

  14. Efficiency and cross-correlation in equity market during global financial crisis: Evidence from China

    Science.gov (United States)

    Ma, Pengcheng; Li, Daye; Li, Shuo

    2016-02-01

    Using one minute high-frequency data of the Shanghai Composite Index (SHCI) and the Shenzhen Composite Index (SZCI) (2007-2008), we employ the detrended fluctuation analysis (DFA) and the detrended cross correlation analysis (DCCA) with rolling window approach to observe the evolution of market efficiency and cross-correlation in pre-crisis and crisis period. Considering the fat-tail distribution of return time series, statistical test based on shuffling method is conducted to verify the null hypothesis of no long-term dependence. Our empirical research displays three main findings. First Shanghai equity market efficiency deteriorated while Shenzhen equity market efficiency improved with the advent of financial crisis. Second the highly positive dependence between SHCI and SZCI varies with time scale. Third financial crisis saw a significant increase of dependence between SHCI and SZCI at shorter time scales but a lack of significant change at longer time scales, providing evidence of contagion and absence of interdependence during crisis.

  15. Three dimensional winds: A maximum cross-correlation application to elastic lidar data

    Energy Technology Data Exchange (ETDEWEB)

    Buttler, W.T.

    1996-05-01

    Maximum cross-correlation techniques have been used with satellite data to estimate winds and sea surface velocities for several years. Los Alamos National Laboratory (LANL) is currently using a variation of the basic maximum cross-correlation technique, coupled with a deterministic application of a vector median filter, to measure transverse winds as a function of range and altitude from incoherent elastic backscatter lidar (light detection and ranging) data taken throughout large volumes within the atmospheric boundary layer. Hourly representations of three-dimensional wind fields, derived from elastic lidar data taken during an air-quality study performed in a region of complex terrain near Sunland Park, New Mexico, are presented and compared with results from an Environmental Protection Agency (EPA) approved laser doppler velocimeter. The wind fields showed persistent large scale eddies as well as general terrain-following winds in the Rio Grande valley.

  16. Active ultrasonic cross-correlation flowmeters for mixed-phase pipe flows

    Science.gov (United States)

    Sheen, S. H.; Raptis, A. C.

    Two ultrasonic flowmeters which employ the active cross-correlation technique and use a simple clamp-on transducer arrangement are discussed. The flowmeter for solid/liquid flows was tested over a wide range of coal concentration in water and oil. The measured velocity based on the peak position of the cross-correlation function is consistently higher by about 15% than the average velocity measured by flow diversion. The origin of the difference results mainly from the flow velocity profiles and the transit-time probability distribution. The flowmeter that can measure particle velocity in a solid/gas flow requires acoustic decoupling arrangement between two sensing stations. The measured velocity is mainly associated with the particles near the wall. Performance of both flowmeters is presented.

  17. Waveform cross correlation for seismic monitoring of underground nuclear explosions. Part II: Synthetic master events

    CERN Document Server

    Bobrov, Dmitry; Rozhkov, Mikhail

    2013-01-01

    Waveform cross correlation is an efficient tool for detection and characterization of seismic signals. The efficiency critically depends on the availability of master events. For the purposes of the Comprehensive Nuclear-Test-Ban Treaty, cross correlation can globally reduce the threshold monitoring by 0.3 to 0.4 magnitude units. In seismically active regions, the optimal choice of master events is straightforward. There are two approaches to populate the global grid in aseismic areas: the replication of real masters and synthetic seismograms calculated for seismic arrays of the International Monitoring System. Synthetic templates depend on the accuracy of shape and amplitude predictions controlled by focal depth and mechanism, source function, velocity structure and attenuation along the master/station path. As in Part I, we test three focal mechanisms (explosion, thrust fault, and actual Harvard CMT solution for one of the April 11, 2012 Sumatera aftershocks) and two velocity structures (ak135 and CRUST 2.0...

  18. A Fast Normalized Cross-Correlation Calculation Method for Motion Estimation

    OpenAIRE

    Luo, Jianwen; Elisa E Konofagou

    2010-01-01

    High-precision motion estimation has become essential in ultrasound-based techniques such as time-domain Doppler and elastography. Normalized cross-correlation (NCC) has been shown as one of the best motion estimators. However, a significant drawback is its associated computational cost, especially when RF signals are used. In this paper, a method based on sum tables developed elsewhere is adapted for fast NCC calculation in ultrasound-based motion estimation, and is tested with respect to th...

  19. Measuring Two Phase Flow Parameters Using Impedance Cross-Correlation and Electromagnetic Flow meters

    OpenAIRE

    Muhamedsalih, Yousif; Lucas, Gary

    2010-01-01

    This paper describes the design and implementation of an impedance cross correlation flow meter which can be used in solids-water pipe flows to measure the local solids volume fraction distribution and the local solids velocity distribution. The system is composed of two arrays of electrodes, separated by an axial distance of 50 mm and each array contains eights electrodes mounted over the internal circumference of the pipe carrying the flow. Furthermore every electrode in each array...

  20. Towards identifying the world stock market cross-correlations: DAX versus Dow Jones

    OpenAIRE

    S. Drozdz; Gruemmer, F.; Ruf, F.; Speth, J.(Institut für Kernphysik, Forschungszentrum Jülich, Jülich, D-52425, Germany)

    2000-01-01

    Effects connected with the world globalization affect also the financial markets. On a way towards quantifying the related characteristics we study the financial empirical correlation matrix of the 60 companies which both the Deutsche Aktienindex (DAX) and the Dow Jones (DJ) industrial average comprised during the years 1990-1999. The time-dependence of the underlying cross-correlations is monitored using a time window of 60 trading days. Our study shows that if the time-zone delays are prope...

  1. Modelling Lyman α forest cross-correlations with LyMAS

    Science.gov (United States)

    Lochhaas, Cassandra; Weinberg, David H.; Peirani, Sébastien; Dubois, Yohan; Colombi, Stéphane; Blaizot, Jérémy; Font-Ribera, Andreu; Pichon, Christophe; Devriendt, Julien

    2016-10-01

    We use the Lyα Mass Association Scheme (LyMAS) to predict cross-correlations at z = 2.5 between dark matter haloes and transmitted flux in the Lyα forest, and compare to cross-correlations measured for quasars and damped Lyα systems (DLAs) from the Baryon Oscillation Spectroscopic Survey (BOSS) by Font-Ribera et al. We calibrate LyMAS using Horizon-AGN hydrodynamical cosmological simulations of a (100 h- 1 Mpc)3 comoving volume. We apply this calibration to a (1 h- 1 Gpc)3 simulation realized with 20483 dark matter particles. In the 100 h- 1 Mpc box, LyMAS reproduces the halo-flux correlations computed from the full hydrodynamic gas distribution very well. In the 1 h- 1 Gpc box, the amplitude of the large-scale cross-correlation tracks the halo bias bh as expected. We provide empirical fitting functions that describe our numerical results. In the transverse separation bins used for the BOSS analyses, LyMAS cross-correlation predictions follow linear theory accurately down to small scales. Fitting the BOSS measurements requires inclusion of random velocity errors; we find best-fitting rms velocity errors of 399 and 252 {km} {s}^{-1} for quasars and DLAs, respectively. We infer bias-weighted mean halo masses of M_h/10^{12} h^{-1} M_{⊙}=2.19^{+0.16}_{-0.15} and 0.69^{+0.16}_{-0.14} for the host haloes of quasars and DLAs, with ˜0.2 dex systematic uncertainty associated with redshift evolution, intergalactic medium parameters, and selection of data fitting range.

  2. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    Science.gov (United States)

    Kirk, D.; Omori, Y.; Benoit-Lévy, A.; Cawthon, R.; Chang, C.; Larsen, P.; Amara, A.; Bacon, D.; Crawford, T. M.; Dodelson, S.; Fosalba, P.; Giannantonio, T.; Holder, G.; Jain, B.; Kacprzak, T.; Lahav, O.; MacCrann, N.; Nicola, A.; Refregier, A.; Sheldon, E.; Story, K. T.; Troxel, M. A.; Vieira, J. D.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Becker, M. R.; Benson, B. A.; Bernstein, G. M.; Bernstein, R. A.; Bleem, L. E.; Bonnett, C.; Bridle, S. L.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carlstrom, J. E.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Reichardt, C. L.; Roodman, A.; Rozo, E.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Simard, G.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Wechsler, R. H.; Weller, J.

    2016-06-01

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg2 of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of zmed ˜ 0.7, while the CMB lensing kernel is broad and peaks at z ˜ 2. The resulting cross-correlation is maximally sensitive to mass fluctuations at z ˜ 0.44. Assuming the Planck 2015 best-fitting cosmology, the amplitude of the DES×SPT cross-power is found to be ASPT = 0.88 ± 0.30 and that from DES×Planck to be APlanck = 0.86 ± 0.39, where A = 1 corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of 2.9σ and 2.2σ, respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photo-z uncertainty and CMB lensing systematics. We calculate a value of A = 1.08 ± 0.36 for DES×SPT when we correct the observations with a simple intrinsic alignment model. With three measurements of this cross-correlation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of cross-correlation. We provide forecasts for the expected signal-to-noise ratio of the combination of the five-year DES survey and SPT-3G.

  3. Effect of distance on trade under slope heterogeneity and cross-correlated effects

    OpenAIRE

    Lugovskyy, Oleksandr; Skiba, Alexandre

    2014-01-01

    The authors argue that endogeneity of transportation costs needs to be taken into account when estimating the effect of distance on trade. Otherwise, the estimates of the distance effect may be biased and inconsistent. Endogenous transportation can introduce slope heterogeneity and spatial correlation. Both issues can be accommodated with the help of Pesaran's cross-correlated effects mean-group (CCEMG) estimator. After applying this methodology, the authors uncover significant compression of...

  4. DETECTING TECHNIQUE OF WEAK PERIODIC PULSE SIGNAL VIA SYNTHESIS OF CROSS-CORRELATION AND CHAOTIC SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Li Yue; Yang Baojun; Lu Peng; Li Shizhe

    2003-01-01

    In this letter, with the synthesis of usual cross-correlation detecting method andchaotic detecting method, a new detecting system for the weak periodic pulse signal is constituted,in which the two methods can play respective preponderance. Theoretical analyses and simulationstudies have shown that the detecting system is very sensitive to the periodic pulse signal understrong noise background and has exceedingly powerful capability of suppressing complex noise.

  5. Dynamic evolution of cross-correlations in the Chinese stock market.

    Science.gov (United States)

    Ren, Fei; Zhou, Wei-Xing

    2014-01-01

    The analysis of cross-correlations is extensively applied for the understanding of interconnections in stock markets and the portfolio risk estimation. Current studies of correlations in Chinese market mainly focus on the static correlations between return series, and this calls for an urgent need to investigate their dynamic correlations. Our study aims to reveal the dynamic evolution of cross-correlations in the Chinese stock market, and offer an exact interpretation for the evolution behavior. The correlation matrices constructed from the return series of 367 A-share stocks traded on the Shanghai Stock Exchange from January 4, 1999 to December 30, 2011 are calculated over a moving window with a size of 400 days. The evolutions of the statistical properties of the correlation coefficients, eigenvalues, and eigenvectors of the correlation matrices are carefully analyzed. We find that the stock correlations are significantly increased in the periods of two market crashes in 2001 and 2008, during which only five eigenvalues significantly deviate from the random correlation matrix, and the systemic risk is higher in these volatile periods than calm periods. By investigating the significant contributors of the deviating eigenvectors in different time periods, we observe a dynamic evolution behavior in business sectors such as IT, electronics, and real estate, which lead the rise (drop) before (after) the crashes. Our results provide new perspectives for the understanding of the dynamic evolution of cross-correlations in the Chines stock markets, and the result of risk estimation is valuable for the application of risk management. PMID:24867071

  6. Passive dispersion analysis on a sea dike using cross-correlations and beamforming

    Science.gov (United States)

    Le Feuvre, Mathieu; Joubert, Anaëlle; Leparoux, Donatienne; Côte, Philippe

    2014-05-01

    In order to passively infer the velocities of surface waves beneath a receiver array, we propose to apply beamforming on cross-correlated noise records. We test the method with synthetic signals generated for a variety of array geometries and noise distributions. We show that the use of cross-correlations cleans the dispersion diagram that would be obtained from a phase-shift analysis alone, by resolving ambiguities between the location of noise sources and the wave velocities. In particular, when nearby noise sources are present, accurate dispersion curves can be inferred from arrays possessing poor azimuthal coverages. This passive method is therefore appropriate for the monitoring of stiffness at the civil-engineering scale, where multiple isolated noise sources may be present and where the field geometry does not always allow to deploy circular arrays. We apply the method to field data obtained from a linear array installed on top of a sea dike. The seismic noise, recorded at high tide during 8 minutes, is essentially generated by impacts of sea waves. In contrast to a phase-shift analysis performed on the noise itself, we show that the use of cross-correlations allow to infer a dispersion curve consistent with an active hammer-shot measurement, in a larger frequency band, ranging from 5 to 55 Hz. This result opens the possibility of following passively the mechanical evolution of embankments on a daily basis.

  7. Plasma fluctuations in a Kaufman thruster. [root mean square magnitude, spectra and cross correlation

    Science.gov (United States)

    Serafini, J. S.; Terdan, F. F.

    1973-01-01

    Measurements of the RMS magnitude, spectra and cross-correlations for the fluctuations in the beam, discharge and neutralizer keeper currents are presented for a 30-cm diameter dished grid ion thrustor for a range of magnetic baffle currents and up to 2.0 amperes beam current. The ratio of RMS to mean ion beam current varied from 0.04 to 0.23. The spectra of the amplitudes of the beam and discharge current fluctuations were taken up to 9 MHz and show that the predominant amplitudes occur at frequencies of 10 kHz or below. The fall-off with increasing frequency is rapid. Frequencies above 100 kHz the spectral levels are 45 kb or more below the maximum peak amplitudes. The cross-correlations revealed the ion beam fluctuations to have large radial and axial scales which implied that the beam fluctuates as a whole or 'in-phase.' The cross-correlations of the beam and neutralizer keeper current fluctuations indicated the neutralizer contributions to the beam fluctuations to be small, but not negligible. The mode of operation of the thrustor (values of beam and magnetic baffle currents) was significant in determining the RMS magnitude and spectral shape of the beam fluctuations. The major oscillations were not found to be directly dependent on the power conditioner inverter frequencies.

  8. MODAL PARAMETERS EXTRACTION WITH CROSS-CORRELATION FUNCTION AND CROSS-POWER SPECTRUM UNDER UNKNOWN EXCITATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In most of real operational conditions only response data are measurable while the actual excitations are unknown, so modal parameter must be extracted only from responses. This paper gives a theoretical formulation for the cross-correlation functions and cross-power spectra between the outputs under the assumption of white-noise excitation. It widens the field of modal analysis under ambient excitation because many classical methods by impulse response functions or frequency response functions can be used easily for modal analysis under unknown excitation. The Polyreference Complex Exponential method and Eigensystem Realization Algorithm using cross-correlation functions in time domain and Orthogonal Polynomial method using cross-power spectra in frequency domain are applied to a steel frame to extract modal parameters under operational conditions. The modal properties of the steel frame from these three methods are compared with those from frequency response functions analysis. The results show that the modal analysis method using cross-correlation functions or cross-power spectra presented in this paper can extract modal parameters efficiently under unknown excitation.

  9. MEASUREMENT OF 21 cm BRIGHTNESS FLUCTUATIONS AT z {approx} 0.8 IN CROSS-CORRELATION

    Energy Technology Data Exchange (ETDEWEB)

    Masui, K. W.; Switzer, E. R.; Calin, L.-M.; Pen, U.-L.; Shaw, J. R. [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George St., Toronto, Ontario, M5S 3H8 (Canada); Banavar, N. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George St., Toronto, Ontario, M5S 3H4 (Canada); Bandura, K. [Department of Physics, McGill University, 3600 Rue University, Montreal, Quebec, H3A 2T8 (Canada); Blake, C. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122 (Australia); Chang, T.-C.; Liao, Y.-W. [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei, 10617, Taiwan (China); Chen, X.; Li, Y.-C. [National Astronomical Observatories, Chinese Academy of Science, 20A Datun Road, Beijing 100012 (China); Natarajan, A.; Peterson, J. B.; Voytek, T. C. [McWilliams Center for Cosmology, Carnegie Mellon University, Department of Physics, 5000 Forbes Ave., Pittsburgh, PA 15213 (United States)

    2013-01-20

    In this Letter, 21 cm intensity maps acquired at the Green Bank Telescope are cross-correlated with large-scale structure traced by galaxies in the WiggleZ Dark Energy Survey. The data span the redshift range 0.6 < z < 1 over two fields totaling {approx}41 deg. sq. and 190 hr of radio integration time. The cross-correlation constrains {Omega}{sub HI} b{sub HI} r = [0.43 {+-} 0.07(stat.) {+-} 0.04(sys.)] Multiplication-Sign 10{sup -3}, where {Omega}{sub HI} is the neutral hydrogen (H I) fraction, r is the galaxy-hydrogen correlation coefficient, and b{sub HI} is the H I bias parameter. This is the most precise constraint on neutral hydrogen density fluctuations in a challenging redshift range. Our measurement improves the previous 21 cm cross-correlation at z {approx} 0.8 both in its precision and in the range of scales probed.

  10. Measuring Distance Ratios with CMB-Galaxy Lensing Cross-correlations

    CERN Document Server

    Das, Sudeep; 10.1103/PhysRevD.79.043509

    2009-01-01

    We propose a method for cosmographic measurements by combining gravitational lensing of the cosmic microwave background (CMB) with cosmic shear surveys. We cross-correlate the galaxy counts in the lens plane with two different source planes: the CMB at $z \\sim 1100$ and galaxies at an intermediate redshift. The ratio of the galaxy count/CMB lensing cross-correlation to the galaxy count/galaxy lensing cross correlation is shown to be a purely geometric quantity, depending only on the distribution function of the source galaxies. By combining Planck, ADEPT and LSST the ratio can be measured to $\\sim 4%$ accuracy, whereas a future polarization based experiment like CMBPOL can make a more precise ($\\sim 1%$) measurement. For cosmological models where the curvature and the equation of state parameter are allowed to vary, the direction of degeneracy defined by the measurement of this ratio is different from that traced out by Baryon Acoustic Oscillation (BAO) measurements. Combining this method with the stacked clu...

  11. Fluctuations in the cross-correlation for fields lacking full diffusivity: The statistics of spurious features.

    Science.gov (United States)

    Yoritomo, John Y; Weaver, Richard L

    2016-07-01

    Inasmuch as ambient noise fields are often not fully diffuse the question arises as to how, or whether, noise cross-correlations converge to Green's function in practice. Well-known theoretical estimates suggest that the quality of convergence scales with the square root of the product of integration time and bandwidth. However, correlations from natural environments often show random features too large to be consistent with fluctuations from insufficient integration time. Here it is argued that empirical seismic correlations suffer in practice from spurious arrivals due to scatterers, and not from insufficient integration time. Estimates are sought for differences by considering a related problem consisting of waves from a finite density of point sources. The resulting cross-correlations are analyzed for their mean and variance. The mean is, as expected, Green's function with amplitude dependent on noise strength. The variance is found to have support for all times up to its maximum at the main arrival. The signal-to-noise ratio there scales with the square root of source density. Numerical simulations support the theoretical estimates. The result permits estimates of spurious arrivals' impact on identification of cross-correlations with Green's function and indicates that spurious arrivals may affect estimates of amplitudes, complicating efforts to infer attenuation. PMID:27475191

  12. Using Cross-Correlation to Detect Upper Mantle Phases beneath Spain and Morocco

    Science.gov (United States)

    Bonatto, L.; Schimmel, M.; Gallart, J.; Morales, J.

    2012-04-01

    A novel technique is implemented to search for weak amplitude upper mantle phases that arrive in the P-wave coda. Cross-correlation and stacking techniques are applied in order to detect waveform similarity and eliminate the source influence from the vertical and radial component of records from single stations. A pilot wave is selected from the vertical component, this wavelet contains the P-wave and part of its coda. Phase cross-correlation (PCC) and geometrically normalized cross-correlation (CCGN) are performed between this pilot and the vertical, and the radial component of each event. It is expected that this procedure detects P to s conversions, and reflections at different mantle discontinuities (such as 410-km and 660-km depth discontinuities). Stacking is used to enhance signals which arrive consistently (near receiver conversions and reflections) and attenuate isolated depth phases and also spurious arrivals. Besides the source equalization, PCC and CCGN provide relative travel times with respect to the P phase through their correlation maxima. The data set used in the real data example is obtained from more than 40 stations selected from the first phase of the IberArray seismic network deployment (TopoIberia project) in south Spain and north Morocco. P-wave reflections and P to s conversions at 410-km and 660-km upper mantle discontinuities were detected beneath the studied region. Both discontinuities are on average within the expected depth range from global studies.

  13. Stochastic Models to Generate Geospatial-, Temporal-, and Cross-Correlated Daily Maximum and Minimum Temperatures

    Directory of Open Access Journals (Sweden)

    Guillermo A. Baigorria

    2014-01-01

    Full Text Available Weather generators are tools used to downscale monthly to seasonal climate forecasts, from numerical climate models to daily values for use as inputs for crop and other environmental models. One main limitation of most of weather generators is that they do not incorporate neither the spatial/temporal correlations between/within sites nor the cross-correlations between variables, characteristics specially important when aggregating, for example, simulated crop yields, freeze events, or heat waves in a watershed or region. Three models were developed to generate realization of daily maximum and minimum temperatures for multiple sites. The first model incorporates only spatial correlation, whereas temporal correlation using a 1-day lag and cross-correlation between variables were added to model one, respectively, by the other two models. Vectors of correlated random numbers were rescaled to temperature values by multiplying each element with the standard deviation and adding the mean of the corresponding weather station. An extension of Crout's algorithm was developed to enable the factorization of nonpositive definite matrices. Monthly spatial correlations of generated daily maximum and minimum temperatures between all pairs of weather stations closely matched their observed counterparts. Performance was analyzed by comparing the root mean squared error, temporal semivariograms, correlation/cross-correlation matrices, multiannual monthly means, and standard deviations.

  14. The CMBR ISW and HI 21-cm Cross-correlation Angular Power Spectrum

    CERN Document Server

    Sarkar, Tapomoy Guha; Bharadwaj, Somnath

    2008-01-01

    The late-time growth of large scale structures (LSS) is imprinted in the CMBR anisotropy through the Integrated Sachs Wolfe (ISW) effect. This is perceived to be a very important observational probe of dark energy. Future observations of redshifted 21-cm radiation from the cosmological neutral hydrogen (HI) distribution hold the potential of probing the LSS over a large redshift range. We have investigated the possibility of detecting the ISW through cross-correlations between the CMBR anisotropies and redshifted 21-cm observations. Assuming that the HI traces the dark matter, we find that the ISW-HI cross-correlation angular power spectrum at an angular multipole l is proportional to the dark matter power spectrum evaluated at the comoving wave number l/r, where r is the comoving distance to the redshift from which the HI signal originated. The amplitude of the cross-correlation signal depends on parameters related to the HI distribution and the growth of cosmological perturbations. However the cross-correla...

  15. Intensity Mapping Cross-Correlations: Connecting the Largest Scales to Galaxy Evolution

    CERN Document Server

    Wolz, L; Blake, C; Wyithe, J S B

    2015-01-01

    Intensity mapping of the neutral hydrogen (HI) is a new observational tool that can be used to efficiently map the large-scale structure of the Universe over wide redshift ranges. The power spectrum of the intensity maps contains cosmological information on the matter distribution and probes galaxy evolution by tracing the HI content of galaxies at different redshifts and the scale-dependence of HI clustering. The cross-correlation of intensity maps with galaxy surveys is a robust measure of the power spectrum which diminishes systematics caused by instrumental effects and foreground removal. We examine the cross-correlation signature at redshift z=0.9 using a variant of the semi-analytical galaxy formation model SAGE (Croton et al. 2016) applied to the Millennium simulation in order to model the HI gas of galaxies as well as their optical magnitudes based on their star-formation history. We determine the clustering of the cross-correlation power for different types of galaxies determined by their colours, ac...

  16. Modeling Lyman-\\alpha\\ Forest Cross-Correlations with LyMAS

    CERN Document Server

    Lochhaas, Cassandra; Peirani, Sébastien; Dubois, Yohan; Colombi, Stéphane; Blaizot, Jérémy; Font-Ribera, Andreu; Pichon, Christophe; Devriendt, Julien

    2015-01-01

    We use the Ly-$\\alpha$ Mass Association Scheme (LyMAS; Peirani et al. 2014) to predict cross-correlations at z = 2.5 between dark matter halos and transmitted flux in the Ly-$\\alpha$ forest, and we compare these predictions to cross-correlations measured for quasars and damped Ly-$\\alpha$ systems (DLAs) from the Baryon Oscillation Spectroscopic Survey (BOSS) by Font-Ribera et al. (2012, 2013). We calibrate and test LyMAS using Horizon-AGN hydrodynamical cosmological simulations of a $(100\\ h^{-1}\\ \\rm{Mpc})^3$ comoving volume with and without AGN feedback. We apply this calibration to a $(1\\ h^{-1}\\ \\rm{Gpc})^3$ simulation realized with $2048^3$ dark matter particles for our primary predictions. In the $100\\ h^{-1}\\ \\rm{Mpc}$ box, LyMAS reproduces the halo-flux correlations computed from the full hydrodynamic gas distribution essentially perfectly. In the $1\\ h^{-1}\\ \\rm{Gpc}$ box, the amplitude of the cross-correlation tracks the halo bias as expected, and the correlation for a halo sample with a distributio...

  17. Characterization of spatiotemporally complex gait patterns using cross-correlation signatures.

    Science.gov (United States)

    Park, Kiwon; Dankowicz, Harry; Hsiao-Wecksler, Elizabeth T

    2012-05-01

    We hypothesize that spatiotemporal joint coupling patterns during gait are closely associated with musculoskeletal injury mechanics. Previous studies examining joint coupling, have primarily focused on coupling between single pairs of neighboring body segments or joints; thus falling short of characterizing the full spatiotemporal complexity across the entire gait apparatus. This study proposes the reliance on properties of the temporal cross-correlation of distinct joint variables as a means to characterize and detect differences in multiple segmental coupling pairs and to quantify how these couplings change between different gait conditions or test groups. In particular, for each subject, a characteristic diagram array is obtained whose entries include the maximum values of the cross-correlation between all pairs of joint variables as well as the associated phase shifts at which these maxima are recorded. Paired t-tests are then used to highlight significant differences in the corresponding entries between two gait conditions. In the present study, this technique was applied to angular displacement and velocity histories across 12 lower extremity joint variables, for healthy subjects with and without a brace on the right knee. As expected, the statistical analysis indicated that the temporal cross-correlations associated with the right knee-angle variables differed the most between the two gait conditions. In addition, significant differences (pknee.

  18. Cross-correlation asymmetries and causal relationships between stock and market risk.

    Directory of Open Access Journals (Sweden)

    Stanislav S Borysov

    Full Text Available We study historical correlations and lead-lag relationships between individual stock risk (volatility of daily stock returns and market risk (volatility of daily returns of a market-representative portfolio in the US stock market. We consider the cross-correlation functions averaged over all stocks, using 71 stock prices from the Standard & Poor's 500 index for 1994-2013. We focus on the behavior of the cross-correlations at the times of financial crises with significant jumps of market volatility. The observed historical dynamics showed that the dependence between the risks was almost linear during the US stock market downturn of 2002 and after the US housing bubble in 2007, remaining at that level until 2013. Moreover, the averaged cross-correlation function often had an asymmetric shape with respect to zero lag in the periods of high correlation. We develop the analysis by the application of the linear response formalism to study underlying causal relations. The calculated response functions suggest the presence of characteristic regimes near financial crashes, when the volatility of an individual stock follows the market volatility and vice versa.

  19. Quantitative analysis of the cross-correlation ultrasonic flow meter by means of system theory

    Science.gov (United States)

    Schneider, F.; Peters, F.; Merzkirch, W.

    2003-05-01

    The physical principles of the ultrasound cross-correlation flow meter are described quantitatively by means of an approach based on system analysis. We extend an earlier theoretical model of Shu (1987 PhD Thesis Universität Karlsruhe) by accounting for additional characteristics of the turbulent pipe flow and making use of characteristic turbulence parameters. The velocity obtained by cross-correlation of the phase-modulated ultrasound signals can be predicted with the theoretical model as a function of the Reynolds number. These theoretical predictions agree favourably with experimental results. It is shown that the velocity determined by cross-correlation is nearly the 'modal value' of the turbulent velocity profile and, thereby, higher than the bulk velocity in the pipe. The investigations include studies of the influence of a number of parameters that can be varied in a practical set-up. It is shown that a calibration of the system, as it is done in practice, is only valid for a specific set of values of these parameters and restricted to fully developed flow in the pipe.

  20. International Data Centre: Reviewed Event Bulletin vs. Waveform Cross Correlation Bulletin

    CERN Document Server

    Bobrov, Dmitry; Given, Jeffrey; Khukhuudei, Urtnasan; Kitov, Ivan; Sitnikov, Kirill; Spiliopoulos, Spilio; Zerbo, Lassina

    2012-01-01

    Our objective is to assess the performance of waveform cross-correlation technique, as applied to automatic and interactive processing of the aftershock sequence of the 2012 Sumatera earthquake relative to the Reviewed Event Bulletin (REB) issued by the International Data Centre. The REB includes 1200 aftershocks between April 11 and May 25 with body wave magnitudes from 3.05 to 6.19. To automatically recover the sequence, we selected sixteen aftershocks with mb between 4.5 and 5.0. These events evenly but sparsely cover the area of the most intensive aftershock activity as recorded during the first two days after the main shock. In our study, waveform templates from only seven IMS array stations with the largest SNRs estimated for the signals from the main shock were used to calculate cross-correlation coefficients over the entire period of 44 days. Approximately 1000000 detections obtained using cross-correlation were then used to build events according to the IDC definition. After conflict resolution betwe...

  1. Waveform cross correlation for seismic monitoring of underground nuclear explosions. Part I: Grand master events

    CERN Document Server

    Bobrov, Dmitry; Rozhkov, Mikhail

    2013-01-01

    Seismic monitoring of the Comprehensive Nuclear-Test-Ban Treaty using waveform cross correlation requires a uniform coverage of the globe with master events well recorded at array stations of the International Monitoring System. The essence of cross correlation as a monitoring tool consists in a continuous comparison of digital waveforms at a given station with waveform templates from the global set of master events. At array stations, cross correlation demonstrates a higher resolution because the time delays at individual sensors from master and slave events are the same but they may differ from theoretical ones used in standard beamforming. In the regions where master events and thus waveform templates are available, one can reduce the amplitude threshold of signal detection by a factor of 2 to 3 relative to standard beamforming and STA/LTA detector used at the International Data Centre. The gain in sensitivity corresponds to a body wave magnitude reduction by 0.3 to 0.4 units and doubles the number of dete...

  2. 3D multiplexed immunoplasmonics microscopy

    Science.gov (United States)

    Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel

    2016-07-01

    Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed

  3. ORMGEN3D, 3-D Crack Geometry FEM Mesh Generator

    International Nuclear Information System (INIS)

    1 - Description of program or function: ORMGEN3D is a finite element mesh generator for computational fracture mechanics analysis. The program automatically generates a three-dimensional finite element model for six different crack geometries. These geometries include flat plates with straight or curved surface cracks and cylinders with part-through cracks on the outer or inner surface. Mathematical or user-defined crack shapes may be considered. The curved cracks may be semicircular, semi-elliptical, or user-defined. A cladding option is available that allows for either an embedded or penetrating crack in the clad material. 2 - Method of solution: In general, one eighth or one-quarter of the structure is modelled depending on the configuration or option selected. The program generates a core of special wedge or collapsed prism elements at the crack front to introduce the appropriate stress singularity at the crack tip. The remainder of the structure is modelled with conventional 20-node iso-parametric brick elements. Element group I of the finite element model consists of an inner core of special crack tip elements surrounding the crack front enclosed by a single layer of conventional brick elements. Eight element divisions are used in a plane orthogonal to the crack front, while the number of element divisions along the arc length of the crack front is user-specified. The remaining conventional brick elements of the model constitute element group II. 3 - Restrictions on the complexity of the problem: Maxima of 5,500 nodes, 4 layers of clad elements

  4. 3D multiplexed immunoplasmonics microscopy.

    Science.gov (United States)

    Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel

    2016-07-21

    Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K(+) channel subunit KV1.1) on human cancer CD44(+) EGFR(+) KV1.1(+) MDA-MB-231 cells and reference CD44(-) EGFR(-) KV1.1(+) 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third

  5. Kuvaus 3D-tulostamisesta hammastekniikassa

    OpenAIRE

    Munne, Mauri; Mustonen, Tuomas; Vähäjylkkä, Jaakko

    2013-01-01

    3D-tulostaminen kehittyy nopeasti ja yleistyy koko ajan. Tulostimien tarkkuuksien kehittyessä 3D-tulostus on ottamassa myös jalansijaa hammastekniikan alalta. Tämän opinnäytetyön tarkoituksena on kuvata 3D-tulostamisen tilaa hammastekniikassa. 3D-tulostaminen on Suomessa vielä melko harvinaista, joten opinnäytetyön tavoitteena on koota yhteen kaikki mahdollinen tieto liittyen 3D-tulostamiseen hammastekniikassa. Tavoitteena on myös 3D-tulostimen testaaminen käytännössä aina suun skannaami...

  6. NIF Ignition Target 3D Point Design

    Energy Technology Data Exchange (ETDEWEB)

    Jones, O; Marinak, M; Milovich, J; Callahan, D

    2008-11-05

    We have developed an input file for running 3D NIF hohlraums that is optimized such that it can be run in 1-2 days on parallel computers. We have incorporated increasing levels of automation into the 3D input file: (1) Configuration controlled input files; (2) Common file for 2D and 3D, different types of capsules (symcap, etc.); and (3) Can obtain target dimensions, laser pulse, and diagnostics settings automatically from NIF Campaign Management Tool. Using 3D Hydra calculations to investigate different problems: (1) Intrinsic 3D asymmetry; (2) Tolerance to nonideal 3D effects (e.g. laser power balance, pointing errors); and (3) Synthetic diagnostics.

  7. 3D multiplexed immunoplasmonics microscopy

    Science.gov (United States)

    Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel

    2016-07-01

    Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed

  8. Crowdsourcing Based 3d Modeling

    Science.gov (United States)

    Somogyi, A.; Barsi, A.; Molnar, B.; Lovas, T.

    2016-06-01

    Web-based photo albums that support organizing and viewing the users' images are widely used. These services provide a convenient solution for storing, editing and sharing images. In many cases, the users attach geotags to the images in order to enable using them e.g. in location based applications on social networks. Our paper discusses a procedure that collects open access images from a site frequently visited by tourists. Geotagged pictures showing the image of a sight or tourist attraction are selected and processed in photogrammetric processing software that produces the 3D model of the captured object. For the particular investigation we selected three attractions in Budapest. To assess the geometrical accuracy, we used laser scanner and DSLR as well as smart phone photography to derive reference values to enable verifying the spatial model obtained from the web-album images. The investigation shows how detailed and accurate models could be derived applying photogrammetric processing software, simply by using images of the community, without visiting the site.

  9. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, D.; et al.

    2015-12-14

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg$^{2}$ of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of $z_{\\rm med} {\\sim} 0.7$, while the CMB lensing kernel is broad and peaks at $z{\\sim}2$. The resulting cross-correlation is maximally sensitive to mass fluctuations at $z{\\sim}0.44$. Assuming the Planck 2015 best-fit cosmology, the amplitude of the DES$\\times$SPT cross-power is found to be $A = 0.88 \\pm 0.30$ and that from DES$\\times$Planck to be $A = 0.86 \\pm 0.39$, where $A=1$ corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of $2.9 \\sigma$ and $2.2 \\sigma$ respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photometric redshift uncertainty and CMB lensing systematics. Significant intrinsic alignment of galaxy shapes would increase the cross-correlation signal inferred from the data; we calculate a value of $A = 1.08 \\pm 0.36$ for DES$\\times$SPT when we correct the observations with a simple IA model. With three measurements of this cross-correlation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of cross-correlation, given the size of the statistical uncertainties and the significant impact of systematic errors, particularly IAs. We provide forecasts for the expected signal-to-noise of the combination of the five-year DES survey and SPT-3G.

  10. Eesti 3D jaoks kitsas / Virge Haavasalu

    Index Scriptorium Estoniae

    Haavasalu, Virge

    2009-01-01

    Produktsioonifirma Digitaalne Sputnik: Kaur ja Kaspar Kallas tegelevad filmide produtseerimise ning 3D digitaalkaamerate tootearendusega (Silicon Imaging LLC). Vendade Kallaste 3D-kaamerast. Kommenteerib Eesti Filmi Sihtasutuse direktor Marge Liiske

  11. Will 3D printers manufacture your meals?

    NARCIS (Netherlands)

    Bommel, K.J.C. van

    2013-01-01

    These days, 3D printers are laying down plastics, metals, resins, and other materials in whatever configurations creative people can dream up. But when the next 3D printing revolution comes, you'll be able to eat it.

  12. 3D Flash LIDAR Space Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc. (ASC) is a small business that has developed 3D Flash LIDAR systems for space and terrestrial applications. 3D Flash LIDAR is...

  13. Face Detection with a 3D Model

    OpenAIRE

    Barbu, Adrian; Lay, Nathan; Gramajo, Gary

    2014-01-01

    This paper presents a part-based face detection approach where the spatial relationship between the face parts is represented by a hidden 3D model with six parameters. The computational complexity of the search in the six dimensional pose space is addressed by proposing meaningful 3D pose candidates by image-based regression from detected face keypoint locations. The 3D pose candidates are evaluated using a parameter sensitive classifier based on difference features relative to the 3D pose. A...

  14. 3D Additive Manufacturing Symposium & Workshop

    OpenAIRE

    Unver, Ertu; Taylor, Andrew

    2015-01-01

    The IMI /3M BIC 3D Additive Manufacturing Symposium and Workshop was hosted by 3M Buckley Innovation Centre on March 17th 2015. The event was attended by the major players in precision engineering, 3D additive design and manufacturing: Representatives from EOS, Renishaw, HK 3D Printing IMI Plc Senior Management team, design engineers, programmers and academics from the University of Huddersfield School of Art Design & Architecture, 3M Buckley centre 3D printing management and designers shared...

  15. Forward ramp in 3D

    Science.gov (United States)

    1997-01-01

    Mars Pathfinder's forward rover ramp can be seen successfully unfurled in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This ramp was not used for the deployment of the microrover Sojourner, which occurred at the end of Sol 2. When this image was taken, Sojourner was still latched to one of the lander's petals, waiting for the command sequence that would execute its descent off of the lander's petal.The image helped Pathfinder scientists determine whether to deploy the rover using the forward or backward ramps and the nature of the first rover traverse. The metallic object at the lower left of the image is the lander's low-gain antenna. The square at the end of the ramp is one of the spacecraft's magnetic targets. Dust that accumulates on the magnetic targets will later be examined by Sojourner's Alpha Proton X-Ray Spectrometer instrument for chemical analysis. At right, a lander petal is visible.The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.' It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  16. 3D modelling for multipurpose cadastre

    NARCIS (Netherlands)

    Abduhl Rahman, A.; Van Oosterom, P.J.M.; Hua, T.C.; Sharkawi, K.H.; Duncan, E.E.; Azri, N.; Hassan, M.I.

    2012-01-01

    Three-dimensional (3D) modelling of cadastral objects (such as legal spaces around buildings, around utility networks and other spaces) is one of the important aspects for a multipurpose cadastre (MPC). This paper describes the 3D modelling of the objects for MPC and its usage to the knowledge of 3D

  17. Beowulf 3D: a case study

    Science.gov (United States)

    Engle, Rob

    2008-02-01

    This paper discusses the creative and technical challenges encountered during the production of "Beowulf 3D," director Robert Zemeckis' adaptation of the Old English epic poem and the first film to be simultaneously released in IMAX 3D and digital 3D formats.

  18. 3D Printing and Its Urologic Applications.

    Science.gov (United States)

    Soliman, Youssef; Feibus, Allison H; Baum, Neil

    2015-01-01

    3D printing is the development of 3D objects via an additive process in which successive layers of material are applied under computer control. This article discusses 3D printing, with an emphasis on its historical context and its potential use in the field of urology.

  19. Expanding Geometry Understanding with 3D Printing

    Science.gov (United States)

    Cochran, Jill A.; Cochran, Zane; Laney, Kendra; Dean, Mandi

    2016-01-01

    With the rise of personal desktop 3D printing, a wide spectrum of educational opportunities has become available for educators to leverage this technology in their classrooms. Until recently, the ability to create physical 3D models was well beyond the scope, skill, and budget of many schools. However, since desktop 3D printers have become readily…

  20. A new approach to quantify power-law cross-correlation and its application to commodity markets

    Science.gov (United States)

    He, Ling-Yun; Chen, Shu-Peng

    2011-10-01

    We proposed a new method: Detrended Moving-average Cross-correlation Analysis (DMCA) to detect the power-law cross-correlation between two correlated non-stationary time series by combining Detrended Cross-Correlation Analysis (DCCA) and Detrended Moving Average (DMA). In order to compare the performance of DMCA and DCCA in the detection of cross-correlation, and to estimate the influence of periodic trend, we generate two cross-correlated time series x(i) and y(i) by a periodic two-component fractionally autoregressive integrated moving average (ARFIMA) process. Then we apply both methods to quantify the cross-correlations of the generated series, whose theoretical values are already known to us. By comparing the results we obtained, we find that the performance of this new approach is comparable to DCCA with less calculating amounts; our method can also reduce the impact of trends; furthermore, DMCA (for background and forward moving average case) outperforms DCCA in more accurate estimation when the analyzed times series are short in length. To provide an example, we also apply this new method to the time series of the real-world data from Brent and WTI crude oil spot markets, to investigate the complex cross-market correlation between these commodity markets. In all, our method is another practical choice to detect the cross-correlation between two short period non-stationary time series, and has potential application to real world problems.

  1. Investigating Mobile Stereoscopic 3D Touchscreen Interaction

    OpenAIRE

    Colley, Ashley; Hakkila, Jonna; SCHOENING, Johannes; Posti, Maaret

    2013-01-01

    3D output is no longer limited to large screens in cinemas or living rooms. Nowadays more and more mobile devices are equipped with autostereoscopic 3D (S3D) touchscreens. As a consequence interaction with 3D content now also happens whilst users are on the move. In this paper we carried out a user study with 27 participants to assess how mobile interaction, i.e. whilst walking, with mobile S3D devices, differs from interaction with 2D mobile touchscreens. We investigate the difference in tou...

  2. User-centered 3D geovisualisation

    DEFF Research Database (Denmark)

    Nielsen, Anette Hougaard

    2004-01-01

    . In a broader perspective, the overall aim is to develop a language in 3D Geovisualisation gained through usability projects and the development of a theoretical background. A conceptual level of user-centered 3D Geovisualisation is introduced by applying a categorisation originating from Virtual Reality......3D Geovisualisation is a multidisciplinary science mainly utilizing geographically related data, developing software systems for 3D visualisation and producing relevant models. In this paper the connection between geoinformation stored as 3D objects and the end user is of special interest...

  3. Wafer level 3-D ICs process technology

    CERN Document Server

    Tan, Chuan Seng; Reif, L Rafael

    2009-01-01

    This book focuses on foundry-based process technology that enables the fabrication of 3-D ICs. The core of the book discusses the technology platform for pre-packaging wafer lever 3-D ICs. However, this book does not include a detailed discussion of 3-D ICs design and 3-D packaging. This is an edited book based on chapters contributed by various experts in the field of wafer-level 3-D ICs process technology. They are from academia, research labs and industry.

  4. View-based 3-D object retrieval

    CERN Document Server

    Gao, Yue

    2014-01-01

    Content-based 3-D object retrieval has attracted extensive attention recently and has applications in a variety of fields, such as, computer-aided design, tele-medicine,mobile multimedia, virtual reality, and entertainment. The development of efficient and effective content-based 3-D object retrieval techniques has enabled the use of fast 3-D reconstruction and model design. Recent technical progress, such as the development of camera technologies, has made it possible to capture the views of 3-D objects. As a result, view-based 3-D object retrieval has become an essential but challenging res

  5. Esiselvitys elintarvikkeiden 3D-tulostamisesta

    OpenAIRE

    Teva, Arno

    2015-01-01

    Opinnäytetyön tavoitteena oli laatia esiselvitys 3D-tulostamisesta elintarvikealalla. 3D-tulostaminen on uusi ja jatkuvasti kehittyvä ala, joka tulee vaikuttamaan myös elintarvikealan kehittymiseen. Työn tarkoituksena oli selvittää elintarvikenäkökulmasta 3D-tulostamiseen liittyviä tekijöitä. Aiheen toimeksiantajana oli Hämeen ammattikorkeakoulu ja kohderyhmänä elintarvikealan Pk-yritykset. Opinnäytetyössä esitellään yleisimpiä 3D-tulostusmenetelmiä ja selvitetään 3D-tulostamista tietokone...

  6. PRIPRAVA MODELOV ZA 3D - TISK

    OpenAIRE

    Črešnik, Igor

    2015-01-01

    V diplomskem delu predstavljamo pripravo modela na 3D-tisk. V prvem delu smo preleteli zgodovino tiska. Predstavili smo tehnologijo 3D-tiska ter različne tehnike tiskanja, ki jih uporabljajo določeni tiskalniki. V nadaljevanju smo pregledali različne tipe 3D-tiskalnikov, ki se uporabljajo za domačo ali komercialno uporabo ter izpostavili njihove prednosti in slabosti. V zadnjem delu diplomskega dela smo na praktičnem primeru 3D-modela hiše prikazali proces priprave modela za 3D-tisk. Pri delu...

  7. 3D-tulostimien tutkiminen painotalolle

    OpenAIRE

    Toivonen, Aleksi

    2014-01-01

    Opinnäytetyön tavoitteena oli perehtyä 3D-tulostamiseen ja tutkia painotaloon sopivia 3D-tulostimia ja 3D-tulostamiseen liittyviä tekniikoita. Opinnäytetyön tavoitteena oli myös pohtia painotalolle mahdollisia 3D-tulostamiseen liittyviä tuotekonsepteja yrityksille ja yksityisille kuluttajille. Painoalan yrityksen tarkoituksena on sijoittaa lähitulevaisuudessa 3D-tulostimeen, joten opinnäytetyö oli ajankohtainen tutkimustyö yritykselle. Opinnäytetyön toimeksiantajana toimi painoalan yritys. ...

  8. BUILDING A HOMEMADE 3D PRINTER

    OpenAIRE

    Tunc, Baran

    2015-01-01

    3D printing has been attracted much attention around the world due to its high potential of new application fields. In this respect, developing and inventing new filament materials for 3D printers or new techniques of 3D printing are the main interest of the many materials scientists. This paper reports a comprehensive overview of 3D printing followed by a summary of my ongoing study of building a composite homemade 3D printer. At this stage of this study, a CNC router was successfully conver...

  9. 3D Printing our future: Now

    OpenAIRE

    Taylor, Andrew; Unver, Ertu

    2015-01-01

    This 3D Printing our Future:Now talk and visual presentation was given to delegates at the IMI 3D Workshop held at 3M Buckley Innovation Centre on 17th March 2015. The event was hosted by 3Mbuckley Innovation Centre for IMI plc a global engineering company, 3M, and leading 3D additive manufacturing technology providers: EOS, Renishaw and HK 3D printing to disseminate and share their experience on the latest 3D additive design and manufacturing technologies available to the engineering an...

  10. Improvements in magnitude precision, using the statistics of relative amplitudes measured by cross correlation

    Science.gov (United States)

    Schaff, David P.; Richards, Paul G.

    2014-04-01

    Standard processing of seismic events for reporting in bulletins is usually done one-at-a time. State-of-the-art relative event methods, often involving cross correlation, are increasingly used and have improved estimates of event parameters for event detection, location and magnitude. This is because relative event techniques can simultaneously reduce measurement error and effects of model error. We show how cross correlation can be used to assign relative magnitudes for neighbouring seismic events distributed over a large region in east Asia and quantify to what extent the uncertainty in these values increases as waveform similarity breaks down. We find that cross correlation works well for magnitude comparison of two events when it is expected that they generate very similar signals even if these may be almost buried in large amounts of noise. This may be the case when investigating repeating earthquakes or nuclear explosions within a few kilometres of each other. Cross correlation is the optimal detector in these cases assuming noise is white and Gaussian, and also provides the least-squares solution for the relative amplitudes. However, when the waveform similarity of the underlying signals breaks down, due to interevent separation distance, source time function differences or focal mechanism differences, these assumptions are no longer valid and a bias is introduced into the relative magnitude measurement. This bias due to degradation of waveform similarity is modelled here with synthetics and an analytic expression for it is derived based on three terms-the cross-correlation coefficient (CC), and the signal-to-noise ratio (SNR) of the larger and smaller events. The analytic expression is a good match to the observed bias in the data. If the equation for relative magnitude is rewritten to correct for the bias due to the CC, a new equation results which is simply the log of the ratio of the L2 norms. The bias due to SNRs is still present because the observed

  11. Web-based interactive visualization of 3D video mosaics using X3D standard

    Institute of Scientific and Technical Information of China (English)

    CHON Jaechoon; LEE Yang-Won; SHIBASAKI Ryosuke

    2006-01-01

    We present a method of 3D image mosaicing for real 3D representation of roadside buildings, and implement a Web-based interactive visualization environment for the 3D video mosaics created by 3D image mosaicing. The 3D image mosaicing technique developed in our previous work is a very powerful method for creating textured 3D-GIS data without excessive data processing like the laser or stereo system. For the Web-based open access to the 3D video mosaics, we build an interactive visualization environment using X3D, the emerging standard of Web 3D. We conduct the data preprocessing for 3D video mosaics and the X3D modeling for textured 3D data. The data preprocessing includes the conversion of each frame of 3D video mosaics into concatenated image files that can be hyperlinked on the Web. The X3D modeling handles the representation of concatenated images using necessary X3D nodes. By employing X3D as the data format for 3D image mosaics, the real 3D representation of roadside buildings is extended to the Web and mobile service systems.

  12. Case study: Beauty and the Beast 3D: benefits of 3D viewing for 2D to 3D conversion

    Science.gov (United States)

    Handy Turner, Tara

    2010-02-01

    From the earliest stages of the Beauty and the Beast 3D conversion project, the advantages of accurate desk-side 3D viewing was evident. While designing and testing the 2D to 3D conversion process, the engineering team at Walt Disney Animation Studios proposed a 3D viewing configuration that not only allowed artists to "compose" stereoscopic 3D but also improved efficiency by allowing artists to instantly detect which image features were essential to the stereoscopic appeal of a shot and which features had minimal or even negative impact. At a time when few commercial 3D monitors were available and few software packages provided 3D desk-side output, the team designed their own prototype devices and collaborated with vendors to create a "3D composing" workstation. This paper outlines the display technologies explored, final choices made for Beauty and the Beast 3D, wish-lists for future development and a few rules of thumb for composing compelling 2D to 3D conversions.

  13. RELAP5-3D User Problems

    Energy Technology Data Exchange (ETDEWEB)

    Riemke, Richard Allan

    2002-09-01

    The Reactor Excursion and Leak Analysis Program with 3D capability1 (RELAP5-3D) is a reactor system analysis code that has been developed at the Idaho National Engineering and Environmental Laboratory (INEEL) for the U. S. Department of Energy (DOE). The 3D capability in RELAP5-3D includes 3D hydrodynamics2 and 3D neutron kinetics3,4. Assessment, verification, and validation of the 3D capability in RELAP5-3D is discussed in the literature5,6,7,8,9,10. Additional assessment, verification, and validation of the 3D capability of RELAP5-3D will be presented in other papers in this users seminar. As with any software, user problems occur. User problems usually fall into the categories of input processing failure, code execution failure, restart/renodalization failure, unphysical result, and installation. This presentation will discuss some of the more generic user problems that have been reported on RELAP5-3D as well as their resolution.

  14. Cross-correlation analysis between Chinese TF contracts and treasury ETF based on high-frequency data

    Science.gov (United States)

    Zhou, Yu; Chen, Shi

    2016-02-01

    In this paper, we investigate the high-frequency cross-correlation relationship between Chinese treasury futures contracts and treasury ETF. We analyze the logarithmic return of these two price series, from which we can conclude that both return series are not normally distributed and the futures markets have greater volatility. We find significant cross-correlation between these two series. We further confirm the relationship using the DCCA coefficient and the DMCA coefficient. We quantify the long-range cross-correlation with DCCA method, and we further show that the relationship is multifractal. An arbitrage algorithm based on DFA regression with stable return is proposed in the last part.

  15. On the interplay between short and long term memory in the power-law cross-correlations setting

    Science.gov (United States)

    Kristoufek, Ladislav

    2015-03-01

    We focus on emergence of the power-law cross-correlations from processes with both short and long term memory properties. In the case of correlated error-terms, the power-law decay of the cross-correlation function comes automatically with the characteristics of separate processes. Bivariate Hurst exponent is then equal to an average of separate Hurst exponents of the analyzed processes. Strength of short term memory has no effect on these asymptotic properties. Implications of these findings for the power-law cross-correlations concept are further discussed.

  16. Method of Removing the Cross-correlation Noise for Dual-input and Dual-output SAR

    Directory of Open Access Journals (Sweden)

    Huang Ping-ping

    2012-03-01

    Full Text Available According to analysis of separating the mixed echo by suppressing the cross-correlation noise in dual-input and dual-output SAR system, a new method based on threshold filter and inverse filter was proposed. The method can eliminate the most energy of cross-correlation noise by threshold filter, which can suppress the cross-correlation noise well. The principle and implementation steps are presented in detail. The computer simulation and account for the integrated sidelobe ratio showed the effectiveness of the proposed method.

  17. Cross-correlations between three units in cat primary auditory cortex.

    Science.gov (United States)

    Eggermont, Jos J; Munguia, Raymundo; Shaw, Gregory

    2013-10-01

    Here we use a modification of the Joint-Peri-Stimulus-Time histogram (JPSTH) to investigate triple correlations between cat auditory cortex neurons. The modified procedure allowed the decomposition of the xy-pair correlation into a part that is due to the correlation of the x and y units with the trigger unit, and a remaining 'pair correlation'. We analyzed 16 sets of 15-minute duration stationary spontaneous recordings in primary auditory cortex (AI) with between 11 and 14 electrodes from 2 arrays of 8 electrodes each that provided spontaneous firing rates above 0.22 sp/s and for which reliable frequency-tuning curves could be obtained and the characteristic frequency (CF) was estimated. Thus we evaluated 11,282 conditional cross-correlation functions. The predictor for the conditional cross-correlation, calculated on the assumption that the trigger unit had no effect on the xy-pair correlation but using the same fraction of xy spikes, was equal to the conventional pair-wise correlation function between units xy. The conditional correlation of the xy-pair due to correlation of the x and/or y unit with the trigger unit decreased with the geometric mean distance of the xy pair to the trigger unit, but was independent of the pair cross-correlation coefficient. The conditional pair correlation coefficient was estimated at 78% of the measured pair correlation coefficient. Assuming a geometric decreasing effect of activities of units on other electrodes on the conditional correlation, we estimated the potential contribution of a large number of contributing units on the measured pair correlation at 35-50 of that correlation. This suggests that conventionally measured pair correlations in auditory cortex under ketamine anesthesia overestimate the 'true pair correlation', likely resulting from massive common input, by potentially up to a factor 2. PMID:23933479

  18. 3D laptop for defense applications

    Science.gov (United States)

    Edmondson, Richard; Chenault, David

    2012-06-01

    Polaris Sensor Technologies has developed numerous 3D display systems using a US Army patented approach. These displays have been developed as prototypes for handheld controllers for robotic systems and closed hatch driving, and as part of a TALON robot upgrade for 3D vision, providing depth perception for the operator for improved manipulation and hazard avoidance. In this paper we discuss the prototype rugged 3D laptop computer and its applications to defense missions. The prototype 3D laptop combines full temporal and spatial resolution display with the rugged Amrel laptop computer. The display is viewed through protective passive polarized eyewear, and allows combined 2D and 3D content. Uses include robot tele-operation with live 3D video or synthetically rendered scenery, mission planning and rehearsal, enhanced 3D data interpretation, and simulation.

  19. 3D Chaotic Functions for Image Encryption

    Directory of Open Access Journals (Sweden)

    Pawan N. Khade

    2012-05-01

    Full Text Available This paper proposes the chaotic encryption algorithm based on 3D logistic map, 3D Chebyshev map, and 3D, 2D Arnolds cat map for color image encryption. Here the 2D Arnolds cat map is used for image pixel scrambling and 3D Arnolds cat map is used for R, G, and B component substitution. 3D Chebyshev map is used for key generation and 3D logistic map is used for image scrambling. The use of 3D chaotic functions in the encryption algorithm provide more security by using the, shuffling and substitution to the encrypted image. The Chebyshev map is used for public key encryption and distribution of generated private keys.

  20. Liquid sodium flow rate measurement by means of fluctuating signal cross correlation

    International Nuclear Information System (INIS)

    Liquid sodium flow rate measurement by means of transit time calculation is a method whose development could be amplified by progresses in design of digital correlators. Transit time between two sensors separated by a known distance is measured with a cross correlation of two flow-dependant fluctuations and is generally estimated by the maximum of the correlation function. In the study discussed below one used signals provided by either thermocouples or electromagnetic flowmeters. This work has been done at the LISOR laboratory (Laboratoire d'Instrumentation Sodium des Renardieres)

  1. Towards a global-scale ambient noise cross-correlation data base

    Science.gov (United States)

    Ermert, Laura; Fichtner, Andreas; Sleeman, Reinoud

    2014-05-01

    We aim to obtain a global-scale data base of ambient seismic noise correlations. This database - to be made publicly available at ORFEUS - will enable us to study the distribution of microseismic and hum sources, and to perform multi-scale full waveform inversion for crustal and mantle structure. Ambient noise tomography has developed into a standard technique. According to theory, cross-correlations equal inter-station Green's functions only if the wave field is equipartitioned or the sources are isotropically distributed. In an attempt to circumvent these assumptions, we aim to investigate possibilities to directly model noise cross-correlations and invert for their sources using adjoint techniques. A data base containing correlations of 'gently' preprocessed noise, excluding preprocessing steps which are explicitly taken to reduce the influence of a non-isotropic source distribution like spectral whitening, is a key ingredient in this undertaking. Raw data are acquired from IRIS/FDSN and ORFEUS. We preprocess and correlate the time series using a tool based on the Python package Obspy which is run in parallel on a cluster of the Swiss National Supercomputing Centre. Correlation is done in two ways: Besides the classical cross-correlation function, the phase cross-correlation is calculated, which is an amplitude-independent measure of waveform similarity and therefore insensitive to high-energy events. Besides linear stacks of these correlations, instantaneous phase stacks are calculated which can be applied as optional weight, enhancing coherent portions of the traces and facilitating the emergence of a meaningful signal. The _STS1 virtual network by IRIS contains about 250 globally distributed stations, several of which have been operating for more than 20 years. It is the first data collection we will use for correlations in the hum frequency range, as the STS-1 instrument response is flat in the largest part of the period range where hum is observed, up to a

  2. Cross-correlated imaging of single-mode photonic crystal rod fiber with distributed mode filtering

    DEFF Research Database (Denmark)

    Laurila, Marko; Barankov, Roman; Jørgensen, Mette Marie;

    2013-01-01

    coupling of higher-order modes. We analyze the modal regimes of the fibers having a mode field diameter of 60 µm by the cross-correlated (C2) imaging method in different wavelength ranges and evaluate the sensitivity of the modal content to various input-coupling conditions. As a result, we experimentally...... identify regimes of resonant coupling between higher-order core modes and cladding band. We demonstrate a passive fiber design in which the higher-order modal content inside the single-mode guiding regime is suppressed by at least 20 dB even for significantly misaligned input-coupling configurations....

  3. The cross-correlation of signals and spatial impression in surround sound reproduction

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The relationship between the cross-correlation coefficients of feeding signals and auditory spatial impression(ASI) which are created by the left,right,left surround and right surround loudspeakers in 5.1 channel surround sound system is investigated by psychoacoustic experiments.The results show that for reproducing by the front left-right or left-right surround loudspeakers pair,the auditory source width(ASW) can be broadened by controlling the crosscorrelation coefficients of feeding signals to some e...

  4. 3-D Technology Approaches for Biological Ecologies

    Science.gov (United States)

    Liu, Liyu; Austin, Robert; U. S-China Physical-Oncology Sciences Alliance (PS-OA) Team

    Constructing three dimensional (3-D) landscapes is an inevitable issue in deep study of biological ecologies, because in whatever scales in nature, all of the ecosystems are composed by complex 3-D environments and biological behaviors. Just imagine if a 3-D technology could help complex ecosystems be built easily and mimic in vivo microenvironment realistically with flexible environmental controls, it will be a fantastic and powerful thrust to assist researchers for explorations. For years, we have been utilizing and developing different technologies for constructing 3-D micro landscapes for biophysics studies in in vitro. Here, I will review our past efforts, including probing cancer cell invasiveness with 3-D silicon based Tepuis, constructing 3-D microenvironment for cell invasion and metastasis through polydimethylsiloxane (PDMS) soft lithography, as well as explorations of optimized stenting positions for coronary bifurcation disease with 3-D wax printing and the latest home designed 3-D bio-printer. Although 3-D technologies is currently considered not mature enough for arbitrary 3-D micro-ecological models with easy design and fabrication, I hope through my talk, the audiences will be able to sense its significance and predictable breakthroughs in the near future. This work was supported by the State Key Development Program for Basic Research of China (Grant No. 2013CB837200), the National Natural Science Foundation of China (Grant No. 11474345) and the Beijing Natural Science Foundation (Grant No. 7154221).

  5. FROM 3D MODEL DATA TO SEMANTICS

    Directory of Open Access Journals (Sweden)

    My Abdellah Kassimi

    2012-01-01

    Full Text Available The semantic-based 3D models retrieval systems have become necessary since the increase of 3D modelsdatabases. In this paper, we propose a new method for the mapping problem between 3D model data andsemantic data involved in semantic based retrieval for 3D models given by polygonal meshes. First, wefocused on extracting invariant descriptors from the 3D models and analyzing them to efficient semanticannotation and to improve the retrieval accuracy. Selected shape descriptors provide a set of termscommonly used to describe visually a set of objects using linguistic terms and are used as semanticconcept to label 3D model. Second, spatial relationship representing directional, topological anddistance relationships are used to derive other high-level semantic features and to avoid the problem ofautomatic 3D model annotation. Based on the resulting semantic annotation and spatial concepts, anontology for 3D model retrieval is constructed and other concepts can be inferred. This ontology is usedto find similar 3D models for a given query model. We adopted the query by semantic example approach,in which the annotation is performed mostly automatically. The proposed method is implemented in our3D search engine (SB3DMR, tested using the Princeton Shape Benchmark Database.

  6. Automatic 3D video format detection

    Science.gov (United States)

    Zhang, Tao; Wang, Zhe; Zhai, Jiefu; Doyen, Didier

    2011-03-01

    Many 3D formats exist and will probably co-exist for a long time even if 3D standards are today under definition. The support for multiple 3D formats will be important for bringing 3D into home. In this paper, we propose a novel and effective method to detect whether a video is a 3D video or not, and to further identify the exact 3D format. First, we present how to detect those 3D formats that encode a pair of stereo images into a single image. The proposed method detects features and establishes correspondences between features in the left and right view images, and applies the statistics from the distribution of the positional differences between corresponding features to detect the existence of a 3D format and to identify the format. Second, we present how to detect the frame sequential 3D format. In the frame sequential 3D format, the feature points are oscillating from frame to frame. Similarly, the proposed method tracks feature points over consecutive frames, computes the positional differences between features, and makes a detection decision based on whether the features are oscillating. Experiments show the effectiveness of our method.

  7. Study of the normalized intensity correlation function of a single-mode laser system with colored cross-correlated noises

    Institute of Scientific and Technical Information of China (English)

    Bing Wang; Xiuqing Wu

    2007-01-01

    A single-mode laser system with colored cross-correlated additive and multiplicative noise terms is considered. By the means of projection operator method, we study the effects of the cross-correlation time τ and the cross-correlation intensity λ between noises on the normalized intensity correlation function C(s). It is found that if λ> 0 (λ< 0), the normalized intensity correlation function C(s) increases (decreases) with increasing the cross-correlation time τ, and at large value of τ, the variation of the normalized intensity correlation function C(s) becomes small. With the increase of the net gain a0, C(s) exhibits a maximum when λ is larger. However, a minimum and a maximum appear on C(s) curves with the increase of a0 when λ becomes smaller and smaller.

  8. A cross-correlation objective function for least-squares migration and visco-acoustic imaging

    KAUST Repository

    Dutta, Gaurav

    2014-08-05

    Conventional acoustic least-squares migration inverts for a reflectivity image that best matches the amplitudes of the observed data. However, for field data applications, it is not easy to match the recorded amplitudes because of the visco-elastic nature of the earth and inaccuracies in the estimation of source signature and strength at different shot locations. To relax the requirement for strong amplitude matching of least-squares migration, we use a normalized cross-correlation objective function that is only sensitive to the similarity between the predicted and the observed data. Such a normalized cross-correlation objective function is also equivalent to a time-domain phase inversion method where the main emphasis is only on matching the phase of the data rather than the amplitude. Numerical tests on synthetic and field data show that such an objective function can be used as an alternative to visco-acoustic least-squares reverse time migration (Qp-LSRTM) when there is strong attenuation in the subsurface and the estimation of the attenuation parameter Qp is insufficiently accurate.

  9. Cross-correlation spin noise spectroscopy of heterogeneous interacting spin systems

    International Nuclear Information System (INIS)

    Interacting multi-component spin systems are ubiquitous in nature and in the laboratory. As such, investigations of inter-species spin interactions are of vital importance. Traditionally, they are studied by experimental methods that are necessarily perturbative: e.g., by intentionally polarizing or depolarizing one spin species while detecting the response of the other(s). Here, we describe and demonstrate an alternative approach based on multi-probe spin noise spectroscopy, which can reveal inter-species spin interactions - under conditions of strict thermal equilibrium - by detecting and cross-correlating the stochastic fluctuation signals exhibited by each of the constituent spin species. Specifically, we consider a two-component spin ensemble that interacts via exchange coupling, and we determine cross-correlations between their intrinsic spin fluctuations. The model is experimentally confirmed using 'two-color' optical spin noise spectroscopy on a mixture of interacting Rb and Cs vapors. Noise correlations directly reveal the presence of inter-species spin exchange, without ever perturbing the system away from thermal equilibrium. These non-invasive and noise-based techniques should be generally applicable to any heterogeneous spin system in which the fluctuations of the constituent components are detectable

  10. The cross-correlation analysis in Z source GX 349+2

    Science.gov (United States)

    Ding, G. Q.; Zhang, W. Y.; Wang, Y. N.; Li, Z. B.; Qu, J. L.; Huang, C. P.

    2016-01-01

    Using all the observations from Rossi X-ray Timing Explorer for Z source GX 349+2, we systematically carry out cross-correlation analysis between its soft and hard X-ray light curves. During the observations from 1998 January 9 to January 29, GX 349+2 traced out the most extensive Z track on its hardness-intensity diagram, making a comprehensive study of cross-correlation on the track. The positive correlations and positively correlated time lags are detected throughout the Z track. Outside the Z track, anti-correlations and anti-correlated time lags are found, but the anti-correlated time lags are much longer than the positively correlated time lags, which might indicate different mechanisms for producing the two types of time lags. We argue that neither the short-term time lag models nor the truncated accretion disc model can account for the long-term time lags in neutron star low-mass X-ray binaries (NS-LMXBs). We suggest that the extended accretion disc corona model could be an alternative model to explain the long-term time lags detected in NS-LMXBs.

  11. Cross-correlating the Thermal Sunyaev-Zel'dovich Effect and the Distribution of Galaxy Clusters

    CERN Document Server

    Fang, Wenjuan; Takada, Masahiro

    2012-01-01

    We present the analytical formulas, derived based on the halo model, to compute the cross-correlation between the thermal Sunyaev-Zel'dovich (SZ) effect and the distribution of galaxy clusters. By binning the clusters according to their redshift and mass, this cross-correlation, the so-called stacked SZ signal, reveals the average SZ profile around these clusters. The stacked SZ signal is available by combining arcminute-resolution cosmic microwave background (CMB) experiments with optical surveys. We derive the error covariance matrix for measuring the stacked SZ signal, and then study forecasts for its detection from ongoing and forthcoming combined CMB-optical surveys. We find that, over a wide range of mass and redshift, the stacked SZ signal can be detected with a significant signal to noise ratio (S/N), whose value peaks for the clusters with intermediate mass and redshift. Our calculation also shows that the stacking method allows one to probe the clusters' SZ profiles over a wide range of scales, even...

  12. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    CERN Document Server

    Kirk, D; Benoit-Lévy, A; Cawthon, R; Chang, C; Larsen, P; Amara, A; Bacon, D; Crawford, T M; Dodelson, S; Fosalba, P; Giannantonio, T; Holder, G; Jain, B; Kacprzak, T; Lahav, O; MacCrann, N; Nicola, A; Refregier, A; Sheldon, E; Story, K T; Troxel, M A; Vieira, J D; Vikram, V; Zuntz, J; Abbott, T M C; Abdalla, F B; Becker, M R; Benson, B A; Bernstein, G M; Bernstein, R A; Bleem, L E; Bonnett, C; Bridle, S L; Brooks, D; Buckley-Geer, E; Burke, D L; Capozzi, D; Carlstrom, J E; Rosell, A Carnero; Kind, M Carrasco; Carretero, J; Crocce, M; Cunha, C E; D'Andrea, C B; da Costa, L N; Desai, S; Diehl, H T; Dietrich, J P; Doel, P; Eifler, T F; Evrard, A E; Flaugher, B; Frieman, J; Gerdes, D W; Goldstein, D A; Gruen, D; Gruendl, R A; Honscheid, K; James, D J; Jarvis, M; Kent, S; Kuehn, K; Kuropatkin, N; Lima, M; March, M; Martini, P; Melchior, P; Miller, C J; Miquel, R; Nichol, R C; Ogando, R; Plazas, A A; Reichardt, C L; Roodman, A; Rozo, E; Rykoff, E S; Sako, M; Sanchez, E; Scarpine, V; Schubnell, M; Sevilla-Noarbe, I; Simard, G; Smith, R C; Soares-Santos, M; Sobreira, F; Suchyta, E; Swanson, M E C; Tarle, G; Thomas, D; Wechsler, R H; Weller, J

    2015-01-01

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg$^{2}$ of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of $z_{\\rm med} {\\sim} 0.7$, while the CMB lensing kernel is broad and peaks at $z{\\sim}2$. The resulting cross-correlation is maximally sensitive to mass fluctuations at $z{\\sim}0.44$. Assuming the Planck 2015 best-fit cosmology, the amplitude of the DES$\\times$SPT cross-power is found to be $A = 0.88 \\pm 0.30$ and that from DES$\\times$Planck to be $A = 0.86 \\pm 0.39$, where $A=1$ corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of $2.9 \\sigma$ and $2.2 \\sigma$ re...

  13. Herschel-ATLAS/GAMA: SDSS cross-correlation induced by weak lensing

    CERN Document Server

    González-Nuevo, J; Negrello, M; Danese, L; De Zotti, G; Amber, S; Baes, M; Bland-Hawthorn, J; Bourne, N; Brough, S; Bussmann, R S; Cai, Z -Y; Cooray, A; Dunne, L; Dye, S; Eales, S; Ibar, E; Ivison, R; Liske, J; Loveday, J; Maddox, S; Michałowski, M J; Schneider, M D; Scott, D; Smith, M W L; Valiante, E; Xia, J -Q

    2014-01-01

    We report a highly significant ($>10\\sigma$) spatial correlation between galaxies with $S_{350\\mu\\rm m}\\ge 30\\,$mJy detected in the equatorial fields of the \\textsl{Herschel} Astrophysical Terahertz Large Area Survey (H-ATLAS) with estimated redshifts $\\gtrsim 1.5$, and SDSS or GAMA galaxies at $0.2\\le z\\le 0.6$. The significance of the cross-correlation is much higher than those reported so far for samples with non-overlapping redshift distributions selected in other wavebands. Extensive, realistic simulations of clustered sub-mm galaxies amplified by foreground structures confirm that the cross-correlation is explained by weak gravitational lensing ($\\mu<2$). The simulations also show that the measured amplitude and range of angular scales of the signal are larger than can be accounted for by galaxy-galaxy weak lensing. However, for scales $\\lesssim 2\\,$arcmin, the signal can be reproduced if SDSS/GAMA galaxies act as signposts of galaxy groups/clusters with halo masses in the range ~$10^{13.2}$--$10^{14...

  14. Lensing reconstruction of cluster-mass cross correlation with cosmic microwave background polarization

    International Nuclear Information System (INIS)

    We extend our maximum likelihood method for reconstructing the cluster-mass cross correlation from cosmic microwave background (CMB) temperature anisotropies and develop new estimators that utilize six different quadratic combinations of CMB temperature and polarization fields. Our maximum likelihood estimators are constructed with delensed CMB temperature and polarization fields by using an assumed model of the convergence field, and they can be iteratively applied to a set of clusters, approaching the optimal condition for the lensing reconstruction as the assumed initial model is refined. Using smoothed particle hydrodynamics simulations, we create a catalog of realistic clusters obtainable from the current Sunyaev-Zel'dovich surveys, and we demonstrate the ability of the maximum likelihood estimators to reconstruct the cluster-mass cross correlation from the massive clusters. The iTT temperature estimator provides a signal-to-noise ratio of a factor of 3 larger than the iEB polarization estimator, unless the detector noise for measuring polarization anisotropies is controlled under 3 μK.

  15. Extending the Galaxy Intrinsic Alignment Self-Calibration to the GII cross-correlation

    CERN Document Server

    Troxel, M A

    2012-01-01

    We extend the 3-point intrinsic alignment self-calibration technique to the gravitational shear-intrinsic ellipticity-intrinsic ellipticity (GII) bispectrum. The proposed technique will allow the measurement and removal of the GII intrinsic alignment contamination from the cross-correlation weak lensing signal. While significantly decreased from using cross-correlations instead of auto-correlation in a single photo-z bin, the GII contamination persists in adjacent photo-z bins and must be accounted for and removed from the lensing signal. We relate the GII and galaxy density-intrinsic ellipticity-intrinsic ellipticity (gII) bispectra through use of the galaxy bias, and develop the estimator necessary to isolate the gII bispectrum from observations. We find that the GII self-calibration technique performs at a level comparable to that of the gravitational shear-gravitational shear-intrinsic ellipticity correlation (GGI) self-calibration technique, with measurement error introduced through the gII estimator gen...

  16. Wavelet-based cross-correlation analysis of structure scaling in turbulent clouds

    CERN Document Server

    Arshakian, T G

    2015-01-01

    We propose a statistical tool to compare the scaling behaviour of turbulence in pairs of molecular cloud maps. Using artificial maps with well defined spatial properties, we calibrate the method and test its limitations to ultimately apply it to a set of observed maps. We develop the wavelet-based weighted cross-correlation (WWCC) method to study the relative contribution of structures of different sizes and their degree of correlation in two maps as a function of spatial scale, and the mutual displacement of structures in the molecular cloud maps. We test the WWCC for circular structures having a single prominent scale and fractal structures showing a self-similar behavior without prominent scales. Observational noise and a finite map size limit the scales where the cross-correlation coefficients and displacement vectors can be reliably measured. For fractal maps containing many structures on all scales, the limitation from the observational noise is negligible for signal-to-noise ratios >5. (abbrev). Applic...

  17. Measurement of the dipole in the cross-correlation function of galaxies

    CERN Document Server

    Gaztanaga, Enrique; Hui, Lam

    2015-01-01

    It is usually assumed that in the linear regime the two-point correlation function of galaxies contains only a monopole, quadrupole and hexadecapole. Looking at cross-correlations between different populations of galaxies, this turns out not to be the case. In particular, the cross-correlations between a bright and a faint population of galaxies contain also a dipole. In this paper we present the first measurement of this dipole. We discuss the three types of effects that contribute to the dipole: relativistic distortions, evolution effects and wide-angle effects. We show that the relativistic distortions and the evolution effects are too small to be detected in the LOWz and CMASS sample of the BOSS survey. We discuss the convention-dependent nature of the wide-angle effect and we show that with the appropriate choice of kernel, a particular version of the wide-angle effect (that we call large-angle effect) can be significantly enhanced. We measure this effect in the dipole with a signal-to-noise of 50, which...

  18. Dissecting the thermal Sunyaev-Zeldovich-gravitational lensing cross-correlation with hydrodynamical simulations

    CERN Document Server

    Hojjati, Alireza; Harnois-Deraps, Joachim; Ma, Yin-Zhe; Van Waerbeke, Ludovic; Hinshaw, Gary; Brun, Amandine M C Le

    2014-01-01

    We use the cosmo-OWLS suite of cosmological hydrodynamical simulations, which includes different galactic feedback models, to predict the cross-correlation signal between weak gravitational lensing and the thermal Sunyaev-Zeldovich (tSZ) $y$-parameter. The predictions are compared to the recent detection reported by van Waerbeke and collaborators. The simulations reproduce the weak lensing-tSZ cross-correlation, $\\xi_{y\\kappa}(\\theta)$, well. The uncertainty arising from different possible feedback models appears to be important on small scales only ($\\theta \\lesssim 10$ arcmin), while the amplitude of the correlation on all scales is sensitive to cosmological parameters that control the growth rate of structure (such as $\\sigma_8$, $\\Omega_m$ and $\\Omega_b$). This study confirms our previous claim (in Ma et al.) that a significant proportion of the signal originates from the diffuse gas component in low-mass ($M_{\\rm{halo}} \\lesssim 10^{14} M_{\\odot}$) clusters as well as from the region beyond the virial ra...

  19. Analysis of cross-correlations between financial markets after the 2008 crisis

    Science.gov (United States)

    Sensoy, A.; Yuksel, S.; Erturk, M.

    2013-10-01

    We analyze the cross-correlation matrix C of the index returns of the main financial markets after the 2008 crisis using methods of random matrix theory. We test the eigenvalues of C for universal properties of random matrices and find that the majority of the cross-correlation coefficients arise from randomness. We show that the eigenvector of the largest deviating eigenvalue of C represents a global market itself. We reveal that high volatility of financial markets is observed at the same times with high correlations between them which lowers the risk diversification potential even if one constructs a widely internationally diversified portfolio of stocks. We identify and compare the connection and cluster structure of markets before and after the crisis using minimal spanning and ultrametric hierarchical trees. We find that after the crisis, the co-movement degree of the markets increases. We also highlight the key financial markets of pre and post crisis using main centrality measures and analyze the changes. We repeat the study using rank correlation and compare the differences. Further implications are discussed.

  20. Investigation of cosmic ray penetration with wavelet cross-correlation analysis

    CERN Document Server

    Yang, Rui-zhi

    2016-01-01

    Aims. We use Fermi and Planck data to calculate the cross correlation between gamma ray signal and gas distribution in different scales in giant molecular clouds (GMC). Then we investigate the cosmic rays (CRs) penetration in GMCs with these informations. Methods.We use the wavelet technique to decompose both the gamma ray and dust opacity maps in different scales, then we calculate the wavelet cross correlation functions in these scales. We also define wavelet response as an analog to the impulsive response in Fourier transform and calculate that in different scales down to Fermi angular resolution. Results. The gamma ray maps above 2 GeV show strong correlation with the dust opacity maps, the correlation coefficient is larger than 0.9 above a scale of 0.4 degree.The derived wavelet response is uniform in different scales. Conclusions. We argue that the CR above 10 GeV can penetrate the giant molecular cloud freely and the CRs distributions in the same energy range are uniform down to parsec scale.

  1. Cross-correlation method for intermediate duration gravitational wave searches associated with gamma-ray bursts

    CERN Document Server

    Coyne, Robert; Owen, Benjamin J

    2015-01-01

    Several models of gamma-ray burst progenitors suggest that the gamma-ray event may be followed by gravitational wave signals of $10^3$-$10^4$ seconds duration (possibly accompanying the so-called X-ray afterglow "plateaus"). We term these signals "intermediate duration" because they are shorter than continuous wave signals but longer than signals traditionally considered as gravitational wave bursts, and are difficult to detect with most burst and continuous wave methods. The cross-correlation technique proposed by [S. Dhurandhar et al., Phys. Rev. D 77, 082001 (2008)], which so far has been used only on continuous wave signals, in principle unifies both burst and continuous wave (as well as matched filtering and stochastic background) methods, reducing them to different choices of which data to correlate on which time scales. Here we perform the first tuning of this cross-correlation technique to intermediate duration signals. We derive theoretical estimates of sensitivity in Gaussian noise in different limi...

  2. On using angular cross-correlations to determine source redshift distributions

    CERN Document Server

    McQuinn, Matthew

    2013-01-01

    We investigate how well the redshift distribution of a population of extragalactic objects can be reconstructed using angular cross-correlations with a sample whose redshifts are known. We derive the minimum variance quadratic estimator, which has simple analytic representations in very applicable limits and is significantly more sensitive than earlier proposed estimation procedures. This estimator is straightforward to apply to observations, it robustly finds the likelihood maximum, and it conveniently selects angular scales at which fluctuations are well approximated as independent between redshift bins and at which linear theory applies. We find that the linear bias times number of objects in a redshift bin generally can be constrained with cross-correlations to fractional error (10^2 n/N)^1/2, where N is the total number of spectra per dz and n is the number of redshift bins spanned by the bulk of the unknown population. The error is often independent of the sky area and sampling fraction. Furthermore, we...

  3. Cross-correlation measurement of quantum shot noise using homemade transimpedance amplifiers.

    Science.gov (United States)

    Hashisaka, Masayuki; Ota, Tomoaki; Yamagishi, Masakazu; Fujisawa, Toshimasa; Muraki, Koji

    2014-05-01

    We report a cross-correlation measurement system, based on a new approach, which can be used to measure shot noise in a mesoscopic conductor at milliKelvin temperatures. In contrast to other measurement systems in which high-speed low-noise voltage amplifiers are commonly used, our system employs homemade transimpedance amplifiers (TAs). The low input impedance of the TAs significantly reduces the crosstalk caused by unavoidable parasitic capacitance between wires. The TAs are designed to have a flat gain over a frequency band from 2 kHz to 1 MHz. Low-noise performance is attained by installing the TAs at a 4 K stage of a dilution refrigerator. Our system thus fulfills the technical requirements for cross-correlation measurements: low noise floor, high frequency band, and negligible crosstalk between two signal lines. Using our system, shot noise generated at a quantum point contact embedded in a quantum Hall system is measured. The good agreement between the obtained shot-noise data and theoretical predictions demonstrates the accuracy of the measurements. PMID:24880392

  4. Optimal CMB map-making in presence of cross-correlated noise

    CERN Document Server

    de Gasperis, Giancarlo; Cabella, Paolo; de Bernardis, Paolo; Vittorio, Nicola

    2016-01-01

    We present an extension of the ROMA map-making algorithm for the generation of optimal CMB temperature and polarization maps. The new code takes into account a possible cross-correlated noise component among the detectors of a CMB experiment. A promising application is the forthcoming LSPE balloon experiment, devoted to the observation of CMB polarization at large angular scales. To check the reliability of the code, we tested the extended ROMA algorithm on real and simulated data of the BOOMERanG(2003) mission, in order to compare our conclusions with already established results. Hence, we performed a preliminary forecast of the LSPE/SWIPE instrument. We found that considering the cross-correlation among the detectors results in a more realistic estimate of the angular power spectra. In particular, the extended ROMA map-making algorithm provides a strong reduction of the spectra error bars. We expect that this improvement will be crucial in constraining the B component of CMB polarization at the largest scal...

  5. Quasar-Lyman $\\alpha$ Forest Cross-Correlation from BOSS DR11 : Baryon Acoustic Oscillations

    CERN Document Server

    Font-Ribera, Andreu; Busca, Nicolas; Miralda-Escudé, Jordi; Ross, Nicholas P; Slosar, Anže; Aubourg, Éric; Bailey, Stephen; Bhardwaj, Vaishali; Bautista, Julian; Beutler, Florian; Bizyaev, Dmitry; Blomqvist, Michael; Brewington, Howard; Brinkmann, Jon; Brownstein, Joel R; Carithers, Bill; Dawson, Kyle S; Delubac, Timothée; Ebelke, Garrett; Eisenstein, Daniel J; Ge, Jian; Kinemuchi, Karen; Lee, Khee-Gan; Malanushenko, Viktor; Malanushenko, Elena; Marchante, Moses; Margala, Daniel; Muna, Demitri; Myers, Adam D; Noterdaeme, Pasquier; Oravetz, Daniel; Palanque-Delabrouille, Nathalie; Pâris, Isabelle; Petitjean, Patrick; Pieri, Matthew M; Rossi, Graziano; Schneider, Donald P; Simmons, Audrey; Viel, Matteo; Yeche, Christophe; York, Donald G

    2013-01-01

    We measure the large-scale cross-correlation of quasars with the Lyman alpha forest absorption, using over 164,000 quasars from Data Release 11 of the SDSS-III Baryon Oscillation Spectroscopic Survey. We extend the previous study of roughly 60,000 quasars from Data Release 9 to larger separations, allowing a measurement of the Baryonic Acoustic Oscillation (BAO) scale along the line of sight $c/(H(z=2.36) ~ r_s) = 9.0 \\pm 0.3$ and across the line of sight $D_A(z=2.36)~ / ~ r_s = 10.8 \\pm 0.4$, consistent with CMB and other BAO data. Using the best fit value of the sound horizon from Planck data ($r_s=147.49 Mpc$), we can translate these results to a measurement of the Hubble parameter of $H(z=2.36) = 226 \\pm 8 km/s$ and of the angular diameter distance of $D_A(z=2.36) = 1590 \\pm 60 Mpc$. The measured cross-correlation function and an update of the code to fit the BAO scale (baofit) are made publicly available.

  6. Pleasant/Unpleasant Filtering for Affective Image Retrieval Based on Cross-Correlation of EEG Features

    Directory of Open Access Journals (Sweden)

    Keranmu Xielifuguli

    2014-01-01

    Full Text Available People often make decisions based on sensitivity rather than rationality. In the field of biological information processing, methods are available for analyzing biological information directly based on electroencephalogram: EEG to determine the pleasant/unpleasant reactions of users. In this study, we propose a sensitivity filtering technique for discriminating preferences (pleasant/unpleasant for images using a sensitivity image filtering system based on EEG. Using a set of images retrieved by similarity retrieval, we perform the sensitivity-based pleasant/unpleasant classification of images based on the affective features extracted from images with the maximum entropy method: MEM. In the present study, the affective features comprised cross-correlation features obtained from EEGs produced when an individual observed an image. However, it is difficult to measure the EEG when a subject visualizes an unknown image. Thus, we propose a solution where a linear regression method based on canonical correlation is used to estimate the cross-correlation features from image features. Experiments were conducted to evaluate the validity of sensitivity filtering compared with image similarity retrieval methods based on image features. We found that sensitivity filtering using color correlograms was suitable for the classification of preferred images, while sensitivity filtering using local binary patterns was suitable for the classification of unpleasant images. Moreover, sensitivity filtering using local binary patterns for unpleasant images had a 90% success rate. Thus, we conclude that the proposed method is efficient for filtering unpleasant images.

  7. The cross-correlation analysis in Z source GX 349+2

    CERN Document Server

    Ding, G Q; Wang, Y N; Li, Z B; Qu, J L; Huang, C P

    2015-01-01

    Using all the observations from Rossi X-ray Timing Explorer for Z source GX 349+2, we systematically carry out cross-correlation analysis between its soft and hard X-ray light curves. During the observations from January 9 to January 29, 1998, GX 349+2 traced out the most extensive Z track on its hardness-intensity diagram, making a comprehensive study of cross-correlation on the track. The positive correlations and positively correlated time lags are detected throughout the Z track. Outside the Z track, anti-correlations and anti-correlated time lags are found, but the anti-correlated time lags are much longer than the positively correlated time lags, which might indicate different mechanisms for producing the two types of time lags. We argue that neither the short-term time lag models nor the truncated accretion disk model can account for the long-term time lags in neutron star low mass X-ray binaries (NS-LMXBs). We suggest that the extended accretion disk corona model could be an alternative model to expla...

  8. Perspectives of cross correlation in seismic monitoring at the International Data Centre

    CERN Document Server

    Bobrov, Dmitry; Zerbo, Lassina

    2011-01-01

    We demonstrate that several techniques based on cross correlation are able to significantly reduce the detection threshold of seismic sources worldwide and to improve the reliability of IDC arrivals by a more accurate estimation of their defining parameters. More than ninety per cent of smaller REB events can be built in automatic processing while completely fitting the REB event definition criteria. The rate of false alarms, as compared to the events rejected from the SEL3 in the current interactive processing, has also been dramatically reduced by several powerful filters. The principal filter is the difference of arrival times between the master events and newly built events at three or more primary stations, which should lie in a narrow range of a few seconds. Two effective pre-filters are f-k analysis and Fprob based on correlation traces instead of original waveforms. As a result, cross correlation may reduce the overall workload related to IDC interactive analysis and provide a precise tool for quality...

  9. 3D Systems” ‘Stuck in the Middle’ of the 3D Printer Boom?

    NARCIS (Netherlands)

    A. Hoffmann (Alan)

    2014-01-01

    textabstract3D Systems, the pioneer of 3D printing, predicted a future where "kids from 8 to 80" could design and print their ideas at home. By 2013, 9 years after the creation of the first working 3D printer, there were more than 30 major 3D printing companies competing for market share. 3DS and it

  10. On the interplay between short and long term memory in the power-law cross-correlations setting

    CERN Document Server

    Kristoufek, Ladislav

    2014-01-01

    We focus on emergence of the power-law cross-correlations from processes with both short and long term memory properties. In the case of correlated error-terms, the power-law decay of the cross-correlation function comes automatically with the characteristics of the separate processes. The bivariate Hurst exponent is then equal to an average of the separate Hurst exponents of the analysed processes. Strength of the short term memory has no effect on these asymptotic properties.

  11. 3D-tulostus : case Printrbot

    OpenAIRE

    Arvekari, Lassi

    2013-01-01

    Opinnäytetyön tavoitteena on selvittää 3D-tulostustekniikan perusteita ja 3D-tulostuksen nykytilannetta. 3D-tulostukseen sopivien mallien luomista tutkitaan ja mallin tekemiseen on etsitty toimivia ohjesääntöjä. Tärkeä osa työtä on tutkia mitä vaiheita 3D-tulostimen hankinnassa kotikäyttöön tulee vastaan. Käytännön kokeita varten opinnäytetyössä on case Printrbot, jossa on tutustuttu edulliseen 3D-tulostuslaitteeseen kokoonpanosta lähtien. Työn kuluessa selvisi että edulliset 3D-tulos...

  12. Spatial data modelling for 3D GIS

    CERN Document Server

    Abdul-Rahman, Alias

    2007-01-01

    This book covers fundamental aspects of spatial data modelling specifically on the aspect of three-dimensional (3D) modelling and structuring. Realisation of ""true"" 3D GIS spatial system needs a lot of effort, and the process is taking place in various research centres and universities in some countries. The development of spatial data modelling for 3D objects is the focus of this book.

  13. Compression of 3D models with NURBS

    OpenAIRE

    Santa Cruz Ducci, Diego; Ebrahimi, Touradj

    2005-01-01

    With recent progress in computing, algorithmics and telecommunications, 3D models are increasingly used in various multimedia applications. Examples include visualization, gaming, entertainment and virtual reality. In the multimedia domain 3D models have been traditionally represented as polygonal meshes. This piecewise planar representation can be thought of as the analogy of bitmap images for 3D surfaces. As bitmap images, they enjoy great flexibility and are particularly well suited to des...

  14. Towards 3C-3D digital holographic fluid velocity vector field measurement—tomographic digital holographic PIV (Tomo-HPIV)

    International Nuclear Information System (INIS)

    Most unsteady and/or turbulent flows of geophysical and engineering interest have a highly three-dimensional (3D) complex topology and their experimental investigation is in pressing need of quantitative velocity measurement methods that are robust and can provide instantaneous 3C-3D velocity field data over a significant volumetric domain of the flow. This paper introduces and demonstrates a new method that uses multiple digital CCD array cameras to record in-line digital holograms of the same volume of seed particles from multiple orientations. This technique uses the same basic equipment as Tomo-PIV minus the camera lenses, it overcomes the depth-of-field problem of digital in-line holography and does not require the complex optical calibration of Tomo-PIV. The digital sensors can be oriented in an optimal manner to overcome the depth-of-field limitation of in-line holograms recorded using digital CCD or CMOS array cameras, resulting in a 3D reconstruction of the seed particles within the volume of interest, which can subsequently be analysed using 3D cross-correlation PIV analysis to yield a 3C-3D velocity field. A demonstration experiment of Tomo-HPIV using uniform translation with nominally 11 µm diameter seed particles shows that the 3D displacement derived from 3D cross-correlation Tomo-HPIV analysis can be measured within 5% of the imposed uniform translation, where the imposed uniform translation has an estimated standard uncertainty of 4.3%. So this paper proposes a multi-camera digital holographic imaging 3C-3D PIV method, which is identified as tomographic digital holographic PIV or Tomo-HPIV

  15. Towards 3C-3D digital holographic fluid velocity vector field measurement—tomographic digital holographic PIV (Tomo-HPIV)

    Science.gov (United States)

    Soria, J.; Atkinson, C.

    2008-07-01

    Most unsteady and/or turbulent flows of geophysical and engineering interest have a highly three-dimensional (3D) complex topology and their experimental investigation is in pressing need of quantitative velocity measurement methods that are robust and can provide instantaneous 3C-3D velocity field data over a significant volumetric domain of the flow. This paper introduces and demonstrates a new method that uses multiple digital CCD array cameras to record in-line digital holograms of the same volume of seed particles from multiple orientations. This technique uses the same basic equipment as Tomo-PIV minus the camera lenses, it overcomes the depth-of-field problem of digital in-line holography and does not require the complex optical calibration of Tomo-PIV. The digital sensors can be oriented in an optimal manner to overcome the depth-of-field limitation of in-line holograms recorded using digital CCD or CMOS array cameras, resulting in a 3D reconstruction of the seed particles within the volume of interest, which can subsequently be analysed using 3D cross-correlation PIV analysis to yield a 3C-3D velocity field. A demonstration experiment of Tomo-HPIV using uniform translation with nominally 11 µm diameter seed particles shows that the 3D displacement derived from 3D cross-correlation Tomo-HPIV analysis can be measured within 5% of the imposed uniform translation, where the imposed uniform translation has an estimated standard uncertainty of 4.3%. So this paper proposes a multi-camera digital holographic imaging 3C-3D PIV method, which is identified as tomographic digital holographic PIV or Tomo-HPIV.

  16. Extraordinary 3D Surface Materials: A practice based exhibition of 3D learning artefacts and prototypes.

    OpenAIRE

    Taylor, Andrew; Harris, Joanne; Unver, Ertu; Lewis, Linda

    2011-01-01

    A collection of 3D prototyped research learning artefacts were exhibited at Surface Design Show 2011. The artefacts on display provided tacit evidence of the 3D concept modelling and reflective learning experiences of a final year BA (Hons) Surface Design for Fashion & Interiors student group using 3D polygon modelling software and additive prototyping technologies (3D Printing) for the first time. The student authored project blog http://extraordinary-3d-materials.blogspot.co.uk/ documen...

  17. 3D modelling for multipurpose cadastre

    OpenAIRE

    Abduhl Rahman, A.; P. J. M. Van Oosterom; T. C. Hua; Sharkawi, K.H.; E. E. Duncan; Azri, N.; Hassan, M. I.

    2012-01-01

    Three-dimensional (3D) modelling of cadastral objects (such as legal spaces around buildings, around utility networks and other spaces) is one of the important aspects for a multipurpose cadastre (MPC). This paper describes the 3D modelling of the objects for MPC and its usage to the knowledge of 3D cadastre since more and more related agencies attempt to develop or embed 3D components into the MPC. We also intend to describe the initiative by Malaysian national mapping and cadastral agency (...

  18. Getting started in 3D with Maya

    CERN Document Server

    Watkins, Adam

    2012-01-01

    Deliver professional-level 3D content in no time with this comprehensive guide to 3D animation with Maya. With over 12 years of training experience, plus several award winning students under his belt, author Adam Watkins is the ideal mentor to get you up to speed with 3D in Maya. Using a structured and pragmatic approach Getting Started in 3D with Maya begins with basic theory of fundamental techniques, then builds on this knowledge using practical examples and projects to put your new skills to the test. Prepared so that you can learn in an organic fashion, each chapter builds on the know

  19. Can 3D Printing change your business?

    OpenAIRE

    Unver, Ertu

    2013-01-01

    This presentation is given to businesses / companies with an interest in 3D Printing and Additive Manufacturing in West Yorkshire, UK Organised by the Calderdale and Kirklees Manufacturing Alliance. http://www.ckma.co.uk/ by Dr Ertu Unver Senior Lecturer / Product Design / MA 3D Digital Design / University of Huddersfield Location : 3M BIC, Date : 11th April, Time : 5.30 – 8pm Additive manufacturing or 3D printing is a process of making a three-dimensional (3D) objects from...

  20. A 3d game in python

    OpenAIRE

    Xu, Minghui

    2014-01-01

    3D game has widely been accepted and loved by many game players. More and more different kinds of 3D games were developed to feed people’s needs. The most common programming language for development of 3D game is C++ nowadays. Python is a high-level scripting language. It is simple and clear. The concise syntax could speed up the development cycle. This project was to develop a 3D game using only Python. The game is about how a cat lives in the street. In order to live, the player need...

  1. Virtual Realization using 3D Password

    Directory of Open Access Journals (Sweden)

    A.B.Gadicha

    2012-03-01

    Full Text Available Current authentication systems suffer from many weaknesses. Textual passwords are commonly used; however, users do not follow their requirements. Users tend to choose meaningful words from dictionaries, which make textual passwords easy to break and vulnerable to dictionary or brute force attacks. Many available graphical passwords have a password space that is less than or equal to the textual password space. Smart cards or tokens can be stolen. Many biometric authentications have been proposed; however, users tend to resist using biometrics because of their intrusiveness and the effect on their privacy. Moreover, biometrics cannot be revoked. In this paper, we present and evaluate our contribution, i.e., the 3D password. The 3D password is a multifactor authentication scheme. To be authenticated, we present a 3D virtual environment where the user navigates and interacts with various objects. The sequence of actions and interactions toward the objects inside the 3D environment constructs the user’s 3D password. The 3D password can combine most existing authentication schemes such as textual passwords, graphical passwords, and various types of biometrics into a 3D virtual environment. The design of the 3D virtual environment and the type of objects selected determine the 3D password key space.

  2. Calibration for 3D Structured Light Measurement

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A calibration procedure was developed for three-dimensional(3D) binocular structured light measurement systems. In virtue of a specially designed pattern, matching points in stereo images are extracted. And then sufficient 3D space points are obtained through pairs of images with the intrinsic and extrinsic parameters of each camera estimated prior and consequently some lights are calibrated by means of multi point fitting. Finally, a mathematical model is applied to interpolate and approximate all dynamic scanning lights based on geometry. The process of calibration method is successfully used in the binocular 3D measurement system based on structured lights and the 3D reconstruction results are satisfying.

  3. Dimensional accuracy of 3D printed vertebra

    Science.gov (United States)

    Ogden, Kent; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Aslan, Can

    2014-03-01

    3D printer applications in the biomedical sciences and medical imaging are expanding and will have an increasing impact on the practice of medicine. Orthopedic and reconstructive surgery has been an obvious area for development of 3D printer applications as the segmentation of bony anatomy to generate printable models is relatively straightforward. There are important issues that should be addressed when using 3D printed models for applications that may affect patient care; in particular the dimensional accuracy of the printed parts needs to be high to avoid poor decisions being made prior to surgery or therapeutic procedures. In this work, the dimensional accuracy of 3D printed vertebral bodies derived from CT data for a cadaver spine is compared with direct measurements on the ex-vivo vertebra and with measurements made on the 3D rendered vertebra using commercial 3D image processing software. The vertebra was printed on a consumer grade 3D printer using an additive print process using PLA (polylactic acid) filament. Measurements were made for 15 different anatomic features of the vertebral body, including vertebral body height, endplate width and depth, pedicle height and width, and spinal canal width and depth, among others. It is shown that for the segmentation and printing process used, the results of measurements made on the 3D printed vertebral body are substantially the same as those produced by direct measurement on the vertebra and measurements made on the 3D rendered vertebra.

  4. 3D Printing Making the Digital Real .

    OpenAIRE

    Miss Prachi More

    2013-01-01

    3D printing is quickly expanding field, with the popularity and uses for 3D printers growing every day. 3D printing can be used to prototype, create replacement parts, and is even versatile enough to print prostheses and medical implants. It will have a growing impact on our world, as more and more people gain access to these amazing machines.[1] In this article, we would like to attempt to give an introduction of the technology. 3Dimensions printing is a method of converting a virtual 3D mod...

  5. 3D-tulostuksen viipalointiohjelmien vertailu

    OpenAIRE

    Virolainen, Ville

    2015-01-01

    Opinnäytetyön tavoitteena on selventää 3D-tulostamisen prosessia yksityisen käyttäjän näkökulmasta sekä luoda testitulostuksia, joiden perusteella pystytään vertailemaan prosessissa käytettävien viipalointiohjelmien toimintaa keskenään. Työssä perehdytään aluksi 3D-tulostuksen teoriataustaan, jonka jälkeen suoritetaan 3D-tulostimella testitulostukset käyttäen kolmea eri viipalointiohjelmaa. 3D-tulostamisella tarkoitetaan prosessia, jonka tarkoituksena on luoda kolmiulotteinen objekti käyt...

  6. Illustrating Mathematics using 3D Printers

    OpenAIRE

    Knill, Oliver; Slavkovsky, Elizabeth

    2013-01-01

    3D printing technology can help to visualize proofs in mathematics. In this document we aim to illustrate how 3D printing can help to visualize concepts and mathematical proofs. As already known to educators in ancient Greece, models allow to bring mathematics closer to the public. The new 3D printing technology makes the realization of such tools more accessible than ever. This is an updated version of a paper included in book Low-Cost 3D Printing for science, education and Sustainable Devel...

  7. BIM tietomalli ja 3D-tulostus

    OpenAIRE

    Myllykoski, Joonas; Palonen, Teemu

    2015-01-01

    Tämän opinnäytetyön tavoitteena oli selvittää miten Tekla Structures ohjelmalla luotu 3D-malli saadaan tulostettua koulun 3D-tulostimella sekä tutkittiin voidaanko Tekla Structuresin ominaisuuksia hyödyntää 3D-tulostamisessa ja miten tulostus onnistuu autocadilla. Selvitimme myös mahdollisia 3D-tulostusteknologian sovelluksia tulevaisuuden rakennustuotannossa ja sen näkymiä rakennusteollisuudessa sekä erilaisia tulostus menetelmiä joita voitaisiin mahdollisesti hyödyntää rakennusteollisuudess...

  8. FastScript3D - A Companion to Java 3D

    Science.gov (United States)

    Koenig, Patti

    2005-01-01

    FastScript3D is a computer program, written in the Java 3D(TM) programming language, that establishes an alternative language that helps users who lack expertise in Java 3D to use Java 3D for constructing three-dimensional (3D)-appearing graphics. The FastScript3D language provides a set of simple, intuitive, one-line text-string commands for creating, controlling, and animating 3D models. The first word in a string is the name of a command; the rest of the string contains the data arguments for the command. The commands can also be used as an aid to learning Java 3D. Developers can extend the language by adding custom text-string commands. The commands can define new 3D objects or load representations of 3D objects from files in formats compatible with such other software systems as X3D. The text strings can be easily integrated into other languages. FastScript3D facilitates communication between scripting languages [which enable programming of hyper-text markup language (HTML) documents to interact with users] and Java 3D. The FastScript3D language can be extended and customized on both the scripting side and the Java 3D side.

  9. 3D PDF - a means of public access to geological 3D - objects, using the example of GTA3D

    Science.gov (United States)

    Slaby, Mark-Fabian; Reimann, Rüdiger

    2013-04-01

    In geology, 3D modeling has become very important. In the past, two-dimensional data such as isolines, drilling profiles, or cross-sections based on those, were used to illustrate the subsurface geology, whereas now, we can create complex digital 3D models. These models are produced with special software, such as GOCAD ®. The models can be viewed, only through the software used to create them, or through viewers available for free. The platform-independent PDF (Portable Document Format), enforced by Adobe, has found a wide distribution. This format has constantly evolved over time. Meanwhile, it is possible to display CAD data in an Adobe 3D PDF file with the free Adobe Reader (version 7). In a 3D PDF, a 3D model is freely rotatable and can be assembled from a plurality of objects, which can thus be viewed from all directions on their own. In addition, it is possible to create moveable cross-sections (profiles), and to assign transparency to the objects. Based on industry-standard CAD software, 3D PDFs can be generated from a large number of formats, or even be exported directly from this software. In geoinformatics, different approaches to creating 3D PDFs exist. The intent of the Authority for Mining, Energy and Geology to allow free access to the models of the Geotectonic Atlas (GTA3D), could not be realized with standard software solutions. A specially designed code converts the 3D objects to VRML (Virtual Reality Modeling Language). VRML is one of the few formats that allow using image files (maps) as textures, and to represent colors and shapes correctly. The files were merged in Acrobat X Pro, and a 3D PDF was generated subsequently. A topographic map, a display of geographic directions and horizontal and vertical scales help to facilitate the use.

  10. Big Data solution for CTBT monitoring: CEA-IDC joint global cross correlation project

    Science.gov (United States)

    Bobrov, Dmitry; Bell, Randy; Brachet, Nicolas; Gaillard, Pierre; Kitov, Ivan; Rozhkov, Mikhail

    2014-05-01

    Waveform cross-correlation when applied to historical datasets of seismic records provides dramatic improvements in detection, location, and magnitude estimation of natural and manmade seismic events. With correlation techniques, the amplitude threshold of signal detection can be reduced globally by a factor of 2 to 3 relative to currently standard beamforming and STA/LTA detector. The gain in sensitivity corresponds to a body wave magnitude reduction by 0.3 to 0.4 units and doubles the number of events meeting high quality requirements (e.g. detected by three and more seismic stations of the International Monitoring System (IMS). This gain is crucial for seismic monitoring under the Comprehensive Nuclear-Test-Ban Treaty. The International Data Centre (IDC) dataset includes more than 450,000 seismic events, tens of millions of raw detections and continuous seismic data from the primary IMS stations since 2000. This high-quality dataset is a natural candidate for an extensive cross correlation study and the basis of further enhancements in monitoring capabilities. Without this historical dataset recorded by the permanent IMS Seismic Network any improvements would not be feasible. However, due to the mismatch between the volume of data and the performance of the standard Information Technology infrastructure, it becomes impossible to process all the data within tolerable elapsed time. To tackle this problem known as "BigData", the CEA/DASE is part of the French project "DataScale". One objective is to reanalyze 10 years of waveform data from the IMS network with the cross-correlation technique thanks to a dedicated High Performance Computer (HPC) infrastructure operated by the Centre de Calcul Recherche et Technologie (CCRT) at the CEA of Bruyères-le-Châtel. Within 2 years we are planning to enhance detection and phase association algorithms (also using machine learning and automatic classification) and process about 30 terabytes of data provided by the IDC to

  11. An aerial 3D printing test mission

    Science.gov (United States)

    Hirsch, Michael; McGuire, Thomas; Parsons, Michael; Leake, Skye; Straub, Jeremy

    2016-05-01

    This paper provides an overview of an aerial 3D printing technology, its development and its testing. This technology is potentially useful in its own right. In addition, this work advances the development of a related in-space 3D printing technology. A series of aerial 3D printing test missions, used to test the aerial printing technology, are discussed. Through completing these test missions, the design for an in-space 3D printer may be advanced. The current design for the in-space 3D printer involves focusing thermal energy to heat an extrusion head and allow for the extrusion of molten print material. Plastics can be used as well as composites including metal, allowing for the extrusion of conductive material. A variety of experiments will be used to test this initial 3D printer design. High altitude balloons will be used to test the effects of microgravity on 3D printing, as well as parabolic flight tests. Zero pressure balloons can be used to test the effect of long 3D printing missions subjected to low temperatures. Vacuum chambers will be used to test 3D printing in a vacuum environment. The results will be used to adapt a current prototype of an in-space 3D printer. Then, a small scale prototype can be sent into low-Earth orbit as a 3-U cube satellite. With the ability to 3D print in space demonstrated, future missions can launch production hardware through which the sustainability and durability of structures in space will be greatly improved.

  12. 3D ultrafast ultrasound imaging in vivo

    International Nuclear Information System (INIS)

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra—and inter-observer variability. (fast track communication)

  13. Reconstructing the Thermal Sunyaev-Zel'dovich Effect in 3D

    CERN Document Server

    Pratten, Geraint

    2014-01-01

    The thermal Sunyaev-Zel'dovich (tSZ) effect is one of the most promising tools we have for probing the baryonic Universe. Unfortunately, the tSZ effect is defined as a line of sight projection of the thermal pressure fluctuations of free-electrons, compromising our ability to probe the thermal history of the Universe by smearing out the tSZ observables. This results in a loss of redshift information diminishing the power of tSZ observations. It is hoped that by cross-correlating the tSZ effect with external tracers we can recover a good fraction of the lost information. Weak lensing (WL) is thought to provide a relatively unbiased probe of the dark Universe in 3D with many upcoming WL surveys having sky coverage that overlaps with current tSZ surveys. Generalising the commonly used tomographic approach, we advocate the use of the spherical Fourier-Bessel (sFB) expansion as a means to perform a full analysis of cross-correlations between the projected (2D) tSZ Compton y-parameter maps and 3D WL-convergence kap...

  14. Immersive 3D Geovisualization in Higher Education

    Science.gov (United States)

    Philips, Andrea; Walz, Ariane; Bergner, Andreas; Graeff, Thomas; Heistermann, Maik; Kienzler, Sarah; Korup, Oliver; Lipp, Torsten; Schwanghart, Wolfgang; Zeilinger, Gerold

    2015-01-01

    In this study, we investigate how immersive 3D geovisualization can be used in higher education. Based on MacEachren and Kraak's geovisualization cube, we examine the usage of immersive 3D geovisualization and its usefulness in a research-based learning module on flood risk, called GEOSimulator. Results of a survey among participating students…

  15. Perception of detail in 3D images

    NARCIS (Netherlands)

    Heyndrickx, I.; Kaptein, R.

    2009-01-01

    A lot of current 3D displays suffer from the fact that their spatial resolution is lower compared to their 2D counterparts. One reason for this is that the multiple views needed to generate 3D are often spatially multiplexed. Besides this, imperfect separation of the left- and right-eye view leads t

  16. 3D printing of functional structures

    NARCIS (Netherlands)

    Krijnen, G.J.M.

    2016-01-01

    The technology colloquial known as ‘3D printing’ has developed in such diversity in printing technologies and application fields that meanwhile it seems anything is possible. However, clearly the ideal 3D Printer, with high resolution, multi-material capability, fast printing, etc. is yet to be deve

  17. Parametrizable cameras for 3D computational steering

    NARCIS (Netherlands)

    Mulder, J.D.; Wijk, J.J. van

    1997-01-01

    We present a method for the definition of multiple views in 3D interfaces for computational steering. The method uses the concept of a point-based parametrizable camera object. This concept enables a user to create and configure multiple views on his custom 3D interface in an intuitive graphical man

  18. 3D Cadastre modelling in Russia

    NARCIS (Netherlands)

    Vandysheva, N.; Tikhonov, V.; Van Oosterom, P.J.M.; Stoter, J.E.; Ploeger, H.D.; Wouters, R.; Penkov, V.

    2011-01-01

    The paper presents the on-going project on 3D cadastre modelling in Russia. The aim of this project is to provide guidance in the development of a prototype and to create favourable legal and institutional conditions for the introduction of 3D cadastre modelling in Russia based on experience of the

  19. Recognition of 3D facial expression dynamics

    NARCIS (Netherlands)

    Sandbach, G.; Zafeiriou, S.; Pantic, Maja; Rueckert, D.

    2012-01-01

    In this paper we propose a method that exploits 3D motion-based features between frames of 3D facial geometry sequences for dynamic facial expression recognition. An expressive sequence is modelled to contain an onset followed by an apex and an offset. Feature selection methods are applied in order

  20. 3-D structures of planetary nebulae

    CERN Document Server

    Steffen, Wolfgang

    2016-01-01

    Recent advances in the 3-D reconstruction of planetary nebulae are reviewed. We include not only results for 3-D reconstructions, but also the current techniques in terms of general methods and software. In order to obtain more accurate reconstructions, we suggest to extend the widely used assumption of homologous nebula expansion to map spectroscopically measured velocity to position along the line of sight.

  1. 3D, or Not to Be?

    Science.gov (United States)

    Norbury, Keith

    2012-01-01

    It may be too soon for students to be showing up for class with popcorn and gummy bears, but technology similar to that behind the 3D blockbuster movie "Avatar" is slowly finding its way into college classrooms. 3D classroom projectors are taking students on fantastic voyages inside the human body, to the ruins of ancient Greece--even to faraway…

  2. 3D Printed Block Copolymer Nanostructures

    Science.gov (United States)

    Scalfani, Vincent F.; Turner, C. Heath; Rupar, Paul A.; Jenkins, Alexander H.; Bara, Jason E.

    2015-01-01

    The emergence of 3D printing has dramatically advanced the availability of tangible molecular and extended solid models. Interestingly, there are few nanostructure models available both commercially and through other do-it-yourself approaches such as 3D printing. This is unfortunate given the importance of nanotechnology in science today. In this…

  3. 3D Printing of Molecular Models

    Science.gov (United States)

    Gardner, Adam; Olson, Arthur

    2016-01-01

    Physical molecular models have played a valuable role in our understanding of the invisible nano-scale world. We discuss 3D printing and its use in producing models of the molecules of life. Complex biomolecular models, produced from 3D printed parts, can demonstrate characteristics of molecular structure and function, such as viral self-assembly,…

  4. 3D Printing. What's the Harm?

    Science.gov (United States)

    Love, Tyler S.; Roy, Ken

    2016-01-01

    Health concerns from 3D printing were first documented by Stephens, Azimi, Orch, and Ramos (2013), who found that commercially available 3D printers were producing hazardous levels of ultrafine particles (UFPs) and volatile organic compounds (VOCs) when plastic materials were melted through the extruder. UFPs are particles less than 100 nanometers…

  5. Multiway calibration in 3D QSAR

    NARCIS (Netherlands)

    Nilsson, J; de Jong, Sietse; Smilde, A

    1997-01-01

    We have introduced multilinear PLS in 3D QSAR and applied it to GRID descriptors from a set of benzamides with affinity to the dopamine D-3 receptor subtype, synthesized as potential drugs against schizophrenia. The key issue in 3D QSAR modelling is to obtain a predictive model that is easy to inter

  6. Waveform modeling and inversion of ambient noise cross-correlation functions in a coastal ocean environment.

    Science.gov (United States)

    Zang, Xiaoqin; Brown, Michael G; Godin, Oleg A

    2015-09-01

    Theoretical studies have shown that cross-correlation functions (CFs) of time series of ambient noise measured at two locations yield approximations to the Green's functions (GFs) that describe propagation between those locations. Specifically, CFs are estimates of weighted GFs. In this paper, it is demonstrated that measured CFs in the 20-70 Hz band can be accurately modeled as weighted GFs using ambient noise data collected in the Florida Straits at ∼100 m depth with horizontal separations of 5 and 10 km. Two weighting functions are employed. These account for (1) the dipole radiation pattern produced by a near-surface source, and (2) coherence loss of surface-reflecting energy in time-averaged CFs resulting from tidal fluctuations. After describing the relationship between CFs and GFs, the inverse problem is considered and is shown to result in an environmental model for which agreement between computed and simulated CFs is good.

  7. The Atacama Cosmology Telescope: Calibration with WMAP Using Cross-Correlations

    CERN Document Server

    Hajian, Amir; Ade, Peter A R; Aguirre, Paula; Amiri, Mandana; Appel, John William; Barrientos, L Felipe; Battistelli, Elia S; Bond, J Richard; Brown, Ben; Burger, Bryce; Chervenak, Jay; Das, Sudeep; Devlin, Mark J; Dicker, Simon R; Doriese, W Bertrand; Dunkley, Joanna; Dunner, Rolando; Essinger-Hileman, Thomas; Fisher, Ryan P; Fowler, Joseph W; Halpern, Mark; Hasselfield, Matthew; Hernandez-Monteagudo, Carlos; Hilton, Gene C; Hilton, Matt; Hincks, Adam D; Hlozek, Renee; Huffenberger, Kevin M; Hughes, David H; Hughes, John P; Infante, Leopoldo; Irwin, Kent D; Juin, Jean Baptiste; Kaul, Madhuri; Klein, Jeff; Kosowsky, Arthur; Lau, Judy M; Limon, Michele; Lin, Yen-Ting; Lupton, Robert H; Marriage, Tobias A; Marsden, Danica; Mauskopf, Phil; Menanteau, Felipe; Moodley, Kavilan; Moseley, Harvey; Netterfield, Calvin B; Niemack, Michael D; Nolta, Michael R; Page, Lyman A; Parker, Lucas; Partridge, Bruce; Reid, Beth; Sehgal, Neelima; Sherwin, Blake D; Sievers, Jon; Spergel, David N; Staggs, Suzanne T; Swetz, Daniel S; Switzer, Eric R; Thornton, Robert; Trac, Hy; Tucker, Carole; Warne, Ryan; Wollack, Ed; Zhao, Yue

    2010-01-01

    We present a new calibration method based on cross-correlations with WMAP and apply it to data from the Atacama Cosmology Telescope (ACT). ACT's observing strategy and map making procedure allows an unbiased reconstruction of the modes in the maps over a wide range of multipoles. By directly matching the ACT maps to WMAP observations in the multipole range of 400 < ell < 1000, we determine the absolute calibration with an uncertainty of 2% in temperature. The precise measurement of the calibration error directly impacts the uncertainties in the cosmological parameters estimated from the ACT power spectra. We also present a combined map based on ACT and WMAP data that has high signal-to-noise over a wide range of multipoles.

  8. THE ATACAMA COSMOLOGY TELESCOPE: CALIBRATION WITH THE WILKINSON MICROWAVE ANISOTROPY PROBE USING CROSS-CORRELATIONS

    International Nuclear Information System (INIS)

    We present a new calibration method based on cross-correlations with the Wilkinson Microwave Anisotropy Probe (WMAP) and apply it to data from the Atacama Cosmology Telescope (ACT). ACT's observing strategy and map-making procedure allows an unbiased reconstruction of the modes in the maps over a wide range of multipoles. By directly matching the ACT maps to WMAP observations in the multipole range of 400 < l < 1000, we determine the absolute calibration with an uncertainty of 2% in temperature. The precise measurement of the calibration error directly impacts the uncertainties in the cosmological parameters estimated from the ACT power spectra. We also present a combined map based on ACT and WMAP data that has a high signal-to-noise ratio over a wide range of multipoles.

  9. Development of cross-correlation spectrometry and the coherent structures of maser sources

    CERN Document Server

    Takefuji, Kazuhiro; Sekido, Mamoru

    2016-01-01

    We have developed a new method of data processing for radio telescope observation data to measure time-dependent temporal coherence, and we named it cross-correlation spectrometry (XCS). XCS is an autocorrelation procedure that expands time lags over the integration time and is applied to data obtained from a single-dish observation. The temporal coherence property of received signals is enhanced by XCS. We tested the XCS technique using the data of strong H2O masers in W3 (H2O), W49N and W75N. We obtained the temporal coherent lengths of the maser emission to be 17.95 $\\pm$ 0.33 {\\mu}s, 26.89 $\\pm$ 0.49 {\\mu}s and 15.95 $\\pm$ 0.46 {\\mu}s for W3 (H2O), W49N and W75N, respectively. These results may indicate the existence of a coherent astrophysical maser.

  10. USING CROSS-CORRELATION THEORY TO EXTRACT MODAL PARAMETERS IN FREQUENCY-DOMAIN

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Conventional modal parameter identifications are usually based on frequency response functions, which require measurements of both the input force and the resulting response. However, in many cases, only response data are available while the actual excitations (such as wind/wave load) are not measurable. Modal parameters estimation must base itself on response-only data. Over the past years, many time-domain modal parameter identification techniques from output-only are proposed. A poly-reference frequency-domain modal identification scheme on response-only is presented. It is based on coupling the cross-correlation theory with conventional frequency-domain modal parameter extraction. An experiment using an airplane model is performed to verify the proposed method.

  11. Cross-Correlation Detection of Point Sources in the WMAP First Year Data

    Institute of Scientific and Technical Information of China (English)

    Jian-Yin Nie; Shuang-Nan Zhang

    2007-01-01

    We apply a Cross-Correlation (CC) method developed previously for detecting gamma-ray point sources to the WMAP first year data by using the Point-Spread Function of WMAP and obtain a full sky CC coefficient map. We find that the CC method is a powerful tool to examine the WMAP foreground residuals which can be further cleaned accordingly. Evident foreground signals are found in the WMAP foreground cleaned maps and the Tegmark cleaned map. In this process 101 point sources are detected, and 26 of them are new sources additional to the originally listed WMAP 208 sources. We estimate the flux of these new sources and verify them by another method. As a result, a revised mask file based on the WMAP first year data is produced by including these new sources.

  12. Cross-correlation video recording of gas-vapor-droplet two-phase flows

    Directory of Open Access Journals (Sweden)

    Volkov Roman S.

    2015-01-01

    Full Text Available The experimental investigations of gas-vapor-droplet two-phase flow formation during single water droplets and their aggregate motion through high-temperature (more than 1000 K combustion products have been conducted with usage of cross-correlation measuring facility and optical methods of “tracer” visualization (“Particle Image Velocimetry” and “Interferometric Particle Imaging”. Modes of droplet motion in high-temperature gases area have been established. It has been determined the influence of the main droplet (sizes, composition, temperature, dispersability, form, velocity and gas (temperature and velocity characteristics on parameters of forming gas-vapor-droplet mixtures. The main elements of advanced firefighting technologies with the usage of time and space apportioned polydisperse composition water droplet flows have been formulated. Physical and predictive mathematical models have been developed to determine the basic parameters of equipment which is necessary for operation with these technology usage.

  13. Determination of velocity vector angles using the directional cross-correlation method

    DEFF Research Database (Denmark)

    Kortbek, Jacob; Jensen, Jørgen Arendt

    2005-01-01

    A method for determining both velocity magnitude and angle in any direction is suggested. The method uses focusing along the velocity direction and cross-correlation for finding the correct velocity magnitude. The angle is found from beamforming directional signals in a number of directions...... and then select the angle with the highest normalized correlation between directional signals. The approach is investigated using Field II simulations and data from the experimental ultrasound scanner RASMUS and with a parabolic flow having a peak velocity of 0.3 m/s. A 7 MHz linear array transducer is used...... with a normal transmission of a focused ultrasound field. The velocity profile estimates from simulations have relative mean standard deviations between 0 . 7% and 7 . 7% for flow between 45 ◦ and 90 ◦ . The angle estimation performance is highly dependent on the choice of the time k tprf · T prf ( correlation...

  14. Graphene thermal transport studies via radio-frequency, cross-correlated Johnson noise thermometry

    Science.gov (United States)

    Crossno, Jesse; Liu, Xiaomeng; Wang, Ke; Harzheim, Achim; Watanabe, Kenji; Taniguchi, Takashi; Ohki, Thomas; Fong, Kin Chung; Kim, Philip

    2015-03-01

    The electronic temperature of a dissipative, mesoscale device can be determined by monitoring the Johnson noise power emitted over a wide frequency range. Using radiometry techniques, we have developed a high-frequency, wide bandwidth, cross-correlation Johnson noise thermometer operating from room temperature to cryogenic levels that is compatible with strong magnetic fields. Precisions ranging from 2 to 25 mK are demonstrated over the temperature range of 3 to 300 K with 1 second of integration time. This non-invasive thermometer has enabled us to perform sensitive electronic thermal transport studies in boron nitride encapsulated monolayer graphene over two orders of magnitude in temperature. This versatile technique also enables precision Fano factor measurements as well as studies of correlated noise phenomena, such as those found in layered Van der Waals heterostructures.

  15. Towards a cross-correlation approach to strong-field dynamics in Black Hole spacetimes

    CERN Document Server

    Jaramillo, J L; Moesta, P; Rezzolla, L

    2012-01-01

    The qualitative and quantitative understanding of near-horizon gravitational dynamics in the strong-field regime represents a challenge both at a fundamental level and in astrophysical applications. Recent advances in numerical relativity and in the geometric characterization of black hole horizons open new conceptual and technical avenues into the problem. We discuss here a research methodology in which spacetime dynamics is probed through the cross-correlation of geometric quantities constructed on the black hole horizon and on null infinity. These two hypersurfaces respond to evolving gravitational fields in the bulk, providing canonical "test screens" in a "scattering"-like perspective onto spacetime dynamics. More specifically, we adopt a 3+1 Initial Value Problem approach to the construction of generic spacetimes and discuss the role and properties of dynamical trapping horizons as canonical inner "screens" in this context. We apply these ideas and techniques to the study of the recoil dynamics in post-...

  16. Dynamic cross correlation studies of wave particle interactions in ULF phenomena

    Science.gov (United States)

    Mcpherron, R. L.

    1979-01-01

    Magnetic field observations made by satellites in the earth's magnetic field reveal a wide variety of ULF waves. These waves interact with the ambient particle populations in complex ways, causing modulation of the observed particle fluxes. This modulation is found to be a function of species, pitch angle, energy and time. The characteristics of this modulation provide information concerning the wave mode and interaction process. One important characteristic of wave-particle interactions is the phase of the particle flux modulation relative to the magnetic field variations. To display this phase as a function of time a dynamic cross spectrum program has been developed. The program produces contour maps in the frequency time plane of the cross correlation coefficient between any particle flux time series and the magnetic field vector. This program has been utilized in several studies of ULF wave-particle interactions at synchronous orbit.

  17. Development of cross-correlation spectrometry and the coherent structures of maser sources

    Science.gov (United States)

    Takefuji, Kazuhiro; Imai, Hiroshi; Sekido, Mamoru

    2016-10-01

    We have developed a new method of data processing for radio telescope observation data to measure time-dependent temporal coherence, and we have named it "cross-correlation spectrometry" (XCS). XCS is an autocorrelation procedure that expands time lags over the integration time and is applied to data obtained from a single-dish observation. The temporal coherence property of received signals is enhanced by XCS. We tested the XCS technique using the data of strong H2O masers in W 3 (H2O), W 49 N, and W 75 N. We obtained the temporal coherent lengths of the maser emission to be 17.95 ± 0.33 μs, 26.89 ± 0.49 μs, and 15.95 ± 0.46 μs for W 3 (H2O), W 49 N, and W 75 N, respectively. These results may indicate the existence of a coherent astrophysical maser.

  18. Measuring cosmic velocities with 21cm intensity mapping and galaxy redshift survey cross-correlation dipoles

    CERN Document Server

    Hall, Alex

    2016-01-01

    We investigate the feasibility of measuring the effects of peculiar velocities in large-scale structure using the dipole of the redshift-space cross-correlation function. We combine number counts of galaxies with brightness-temperature fluctuations from 21cm intensity mapping, demonstrating that the dipole may be measured at modest significance ($\\lesssim 2\\sigma$) by combining the upcoming radio survey CHIME with the future redshift surveys of DESI and Euclid. More significant measurements ($\\lesssim~10\\sigma$) will be possible by combining intensity maps from the SKA with these of DESI or Euclid, and an even higher significance measurement ($\\lesssim 100\\sigma$) may be made by combining observables completely internally to the SKA. We account for effects such as contamination by wide-angle terms, interferometer noise and beams in the intensity maps, non-linear enhancements to the power spectrum, stacking multiple populations, sensitivity to the magnification slope, and the possibility that number counts and...

  19. Analysis of cross-correlations in electroencephalogram signals as an approach to proactive diagnosis of schizophrenia

    CERN Document Server

    Timashev, Serge F; Polyakov, Yuriy S; Demin, Sergey A; Kaplan, Alexander Ya

    2011-01-01

    We apply flicker-noise spectroscopy (FNS), a time series analysis method operating on structure functions and power spectrum estimates, to study the clinical electroencephalogram (EEG) signals recorded in children/adolescents (11 to 14 years of age) with diagnosed schizophrenia-spectrum symptoms at the National Center for Psychiatric Health (NCPH) of the Russian Academy of Medical Sciences. The EEG signals for these subjects were compared with the signals for a control sample of chronically depressed children/adolescents. The purpose of the study is to look for diagnostic signs of subjects' susceptibility to schizophrenia in the FNS parameters for specific electrodes and cross-correlations between the signals simultaneously measured at different points on the scalp. Our analysis of EEG signals from scalp-mounted electrodes at locations F3 and F4, which are symmetrically positioned in the left and right frontal areas of cerebral cortex, respectively, demonstrates an essential role of frequency-phase synchroniz...

  20. Limited Feedback for 3D Massive MIMO under 3D-UMa and 3D-UMi Scenarios

    Directory of Open Access Journals (Sweden)

    Zheng Hu

    2015-01-01

    Full Text Available For three-dimensional (3D massive MIMO utilizing the uniform rectangular array (URA in the base station (BS, we propose a limited feedback transmission scheme in which the channel state information (CSI feedback operations for horizontal domain and vertical domain are separate. Compared to the traditional feedback scheme, the scheme can reduce the feedback overhead, code word index search complexity, and storage requirement. Also, based on the zenith of departure angle (ZoD distribution in 3D-Urban Macro Cell (3D-UMa and 3D-Urban Micro Cell (3D-UMi scenarios, we propose the angle quantization codebook for vertical domain, while the codebook of long term evolution-advanced (LTE-Advanced is still adopted in horizontal domain to preserve compatibility with the LTE-Advanced. Based on the angle quantization codebook, the subsampled 3-bit DFT codebook is designed for vertical domain. The system-level simulation results reveal that, to compromise the feedback overhead and system performance, 2-bit codebook for 3D-UMa scenario and 3-bit codebook for 3D-UMi scenario can meet requirements in vertical domain. The feedback period for vertical domain can also be extended appropriately to reduce the feedback overhead.

  1. Density-Based 3D Shape Descriptors

    Directory of Open Access Journals (Sweden)

    Schmitt Francis

    2007-01-01

    Full Text Available We propose a novel probabilistic framework for the extraction of density-based 3D shape descriptors using kernel density estimation. Our descriptors are derived from the probability density functions (pdf of local surface features characterizing the 3D object geometry. Assuming that the shape of the 3D object is represented as a mesh consisting of triangles with arbitrary size and shape, we provide efficient means to approximate the moments of geometric features on a triangle basis. Our framework produces a number of 3D shape descriptors that prove to be quite discriminative in retrieval applications. We test our descriptors and compare them with several other histogram-based methods on two 3D model databases, Princeton Shape Benchmark and Sculpteur, which are fundamentally different in semantic content and mesh quality. Experimental results show that our methodology not only improves the performance of existing descriptors, but also provides a rigorous framework to advance and to test new ones.

  2. Fabrication of 3D Silicon Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kok, A.; Hansen, T.E.; Hansen, T.A.; Lietaer, N.; Summanwar, A.; /SINTEF, Oslo; Kenney, C.; Hasi, J.; /SLAC; Da Via, C.; /Manchester U.; Parker, S.I.; /Hawaii U.

    2012-06-06

    Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated the original (single sided double column type) 3D detectors in two prototype runs and the third run is now on-going. This paper reports the status of this fabrication work and the resulted yield. The work of other groups such as the development of double sided 3D detectors is also briefly reported.

  3. Maintaining and troubleshooting your 3D printer

    CERN Document Server

    Bell, Charles

    2014-01-01

    Maintaining and Troubleshooting Your 3D Printer by Charles Bell is your guide to keeping your 3D printer running through preventive maintenance, repair, and diagnosing and solving problems in 3D printing. If you've bought or built a 3D printer such as a MakerBot only to be confounded by jagged edges, corner lift, top layers that aren't solid, or any of a myriad of other problems that plague 3D printer enthusiasts, then here is the book to help you get past all that and recapture the joy of creative fabrication. The book also includes valuable tips for builders and those who want to modify the

  4. 3D-grafiikka ja pelimoottorit

    OpenAIRE

    Sillanpää, Otto

    2014-01-01

    Tässä opinnäytetyössä tutkitaan miten 3D-mallit saadaan sellaiseen muotoon, että ne olisivat käytettävissä eri pelimoottoreissa. Tutkimuksen tarkoituksena on selvittää, miten luodaan 3D-malleja pelimoottoreihin, sekä miten 3D-mallinnusohjelmat ja pelimoottorit eroavat toisistaan, kun käsitellään 3D-malleja. Tässä työssä pelimoottoreina toimivat Valven Source sekä Epic Gamesin Unreal Engine 3. 3D-mallinnusohjelmista käytössä olivat Autodeskin 3ds Max 2014 ja Blender Foundationin Blender 2.7...

  5. 6D Interpretation of 3D Gravity

    CERN Document Server

    Herfray, Yannick; Scarinci, Carlos

    2016-01-01

    We show that 3D gravity, in its pure connection formulation, admits a natural 6D interpretation. The 3D field equations for the connection are equivalent to 6D Hitchin equations for the Chern-Simons 3-form in the total space of the principal bundle over the 3-dimensional base. Turning this construction around one gets an explanation of why the pure connection formulation of 3D gravity exists. More generally, we interpret 3D gravity as the dimensional reduction of the 6D Hitchin theory. To this end, we show that any SU(2) invariant closed 3-form in the total space of the principal SU(2) bundle can be parametrised by a connection together with a 2-form field on the base. The dimensional reduction of the 6D Hitchin theory then gives rise to 3D gravity coupled to a topological 2-form field.

  6. Investigation of measurement sensitivities in cross-correlation Doppler global velocimetry

    Science.gov (United States)

    Cadel, Daniel R.; Lowe, K. Todd

    2016-11-01

    Cross-correlation Doppler global velocimetry (CC-DGV) is a flow measurement technique based on the estimation of Doppler frequency shift of scattered light by means of cross-correlating two filtered intensity signals. The signal characteristics of CC-DGV result in fundamental limits for estimation variance as well as the possibility for estimator bias. The current study assesses these aspects theoretically and via Monte Carlo signal simulations. A signal model is developed using canonical numerical functions for the iodine absorption cell and incorporating Poisson and Gaussian signal noise models. Along with consideration of the analytical form of the Cramér-Rao lower bound, best practices for system settings are discussed. The CC-DGV signal processing routine is then assessed by a series of Monte Carlo simulations studying the effect of temperature mismatch between flow signal and reference detector cells, velocity magnitude, and discretization error in the frequency modulation. A measurement bias was observed; the magnitude of the bias is a weak function of the cell temperature mismatch, but it is independent of the flow velocity magnitude. The measurement variance was found to approach the Cramér-Rao lower bound for optimized conditions. A cyclical bias error resulting from the discrete nature of the laser frequency sweep is also observed with maximum errors of ± 1.0 % of the laser frequency scan step size, corresponding to peak errors of ± 0.61 m s-1 for typical settings. Overall, the signal estimator is found to perform best for matched cell temperatures, small frequency step size, and high velocity regimes, where the relative bias errors are collectively minimized.

  7. Wavelet-based cross-correlation analysis of structure scaling in turbulent clouds

    Science.gov (United States)

    Arshakian, Tigran G.; Ossenkopf, Volker

    2016-01-01

    Aims: We propose a statistical tool to compare the scaling behaviour of turbulence in pairs of molecular cloud maps. Using artificial maps with well-defined spatial properties, we calibrate the method and test its limitations to apply it ultimately to a set of observed maps. Methods: We develop the wavelet-based weighted cross-correlation (WWCC) method to study the relative contribution of structures of different sizes and their degree of correlation in two maps as a function of spatial scale, and the mutual displacement of structures in the molecular cloud maps. Results: We test the WWCC for circular structures having a single prominent scale and fractal structures showing a self-similar behaviour without prominent scales. Observational noise and a finite map size limit the scales on which the cross-correlation coefficients and displacement vectors can be reliably measured. For fractal maps containing many structures on all scales, the limitation from observational noise is negligible for signal-to-noise ratios ≳5. We propose an approach for the identification of correlated structures in the maps, which allows us to localize individual correlated structures and recognize their shapes and suggest a recipe for recovering enhanced scales in self-similar structures. The application of the WWCC to the observed line maps of the giant molecular cloud G 333 allows us to add specific scale information to the results obtained earlier using the principal component analysis. The WWCC confirms the chemical and excitation similarity of 13CO and C18O on all scales, but shows a deviation of HCN at scales of up to 7 pc. This can be interpreted as a chemical transition scale. The largest structures also show a systematic offset along the filament, probably due to a large-scale density gradient. Conclusions: The WWCC can compare correlated structures in different maps of molecular clouds identifying scales that represent structural changes, such as chemical and phase transitions

  8. Analysis of cross-correlations in electroencephalogram signals as an approach to proactive diagnosis of schizophrenia

    Science.gov (United States)

    Timashev, Serge F.; Panischev, Oleg Yu.; Polyakov, Yuriy S.; Demin, Sergey A.; Kaplan, Alexander Ya.

    2012-02-01

    We apply flicker-noise spectroscopy (FNS), a time series analysis method operating on structure functions and power spectrum estimates, to study the clinical electroencephalogram (EEG) signals recorded in children/adolescents (11 to 14 years of age) with diagnosed schizophrenia-spectrum symptoms at the National Center for Psychiatric Health (NCPH) of the Russian Academy of Medical Sciences. The EEG signals for these subjects were compared with the signals for a control sample of chronically depressed children/adolescents. The purpose of the study is to look for diagnostic signs of subjects' susceptibility to schizophrenia in the FNS parameters for specific electrodes and cross-correlations between the signals simultaneously measured at different points on the scalp. Our analysis of EEG signals from scalp-mounted electrodes at locations F3 and F4, which are symmetrically positioned in the left and right frontal areas of cerebral cortex, respectively, demonstrates an essential role of frequency-phase synchronization, a phenomenon representing specific correlations between the characteristic frequencies and phases of excitations in the brain. We introduce quantitative measures of frequency-phase synchronization and systematize the values of FNS parameters for the EEG data. The comparison of our results with the medical diagnoses for 84 subjects performed at NCPH makes it possible to group the EEG signals into 4 categories corresponding to different risk levels of subjects' susceptibility to schizophrenia. We suggest that the introduced quantitative characteristics and classification of cross-correlations may be used for the diagnosis of schizophrenia at the early stages of its development.

  9. A novel coefficient for detecting and quantifying asymmetry of California electricity market based on asymmetric detrended cross-correlation analysis

    Science.gov (United States)

    Wang, Fang

    2016-06-01

    In order to detect and quantify asymmetry of two time series, a novel cross-correlation coefficient is proposed based on recent asymmetric detrended cross-correlation analysis (A-DXA), which we called A-DXA coefficient. The A-DXA coefficient, as an important extension of DXA coefficient ρ D X A , contains two directional asymmetric cross-correlated indexes, describing upwards and downwards asymmetric cross-correlations, respectively. By using the information of directional covariance function of two time series and directional variance function of each series itself instead of power-law between the covariance function and time scale, the proposed A-DXA coefficient can well detect asymmetry between the two series no matter whether the cross-correlation is significant or not. By means of the proposed A-DXA coefficient conducted over the asymmetry for California electricity market, we found that the asymmetry between the prices and loads is not significant for daily average data in 1999 yr market (before electricity crisis) but extremely significant for those in 2000 yr market (during the crisis). To further uncover the difference of asymmetry between the years 1999 and 2000, a modified H statistic (MH) and ΔMH statistic are proposed. One of the present contributions is that the high MH values calculated for hourly data exist in majority months in 2000 market. Another important conclusion is that the cross-correlation with downwards dominates over the whole 1999 yr in contrast to the cross-correlation with upwards dominates over the 2000 yr.

  10. Quantifying and modeling long-range cross correlations in multiple time series with applications to world stock indices

    Science.gov (United States)

    Wang, Duan; Podobnik, Boris; Horvatić, Davor; Stanley, H. Eugene

    2011-04-01

    We propose a modified time lag random matrix theory in order to study time-lag cross correlations in multiple time series. We apply the method to 48 world indices, one for each of 48 different countries. We find long-range power-law cross correlations in the absolute values of returns that quantify risk, and find that they decay much more slowly than cross correlations between the returns. The magnitude of the cross correlations constitutes “bad news” for international investment managers who may believe that risk is reduced by diversifying across countries. We find that when a market shock is transmitted around the world, the risk decays very slowly. We explain these time-lag cross correlations by introducing a global factor model (GFM) in which all index returns fluctuate in response to a single global factor. For each pair of individual time series of returns, the cross correlations between returns (or magnitudes) can be modeled with the autocorrelations of the global factor returns (or magnitudes). We estimate the global factor using principal component analysis, which minimizes the variance of the residuals after removing the global trend. Using random matrix theory, a significant fraction of the world index cross correlations can be explained by the global factor, which supports the utility of the GFM. We demonstrate applications of the GFM in forecasting risks at the world level, and in finding uncorrelated individual indices. We find ten indices that are practically uncorrelated with the global factor and with the remainder of the world indices, which is relevant information for world managers in reducing their portfolio risk. Finally, we argue that this general method can be applied to a wide range of phenomena in which time series are measured, ranging from seismology and physiology to atmospheric geophysics.

  11. A novel coefficient for detecting and quantifying asymmetry of California electricity market based on asymmetric detrended cross-correlation analysis.

    Science.gov (United States)

    Wang, Fang

    2016-06-01

    In order to detect and quantify asymmetry of two time series, a novel cross-correlation coefficient is proposed based on recent asymmetric detrended cross-correlation analysis (A-DXA), which we called A-DXA coefficient. The A-DXA coefficient, as an important extension of DXA coefficient ρDXA, contains two directional asymmetric cross-correlated indexes, describing upwards and downwards asymmetric cross-correlations, respectively. By using the information of directional covariance function of two time series and directional variance function of each series itself instead of power-law between the covariance function and time scale, the proposed A-DXA coefficient can well detect asymmetry between the two series no matter whether the cross-correlation is significant or not. By means of the proposed A-DXA coefficient conducted over the asymmetry for California electricity market, we found that the asymmetry between the prices and loads is not significant for daily average data in 1999 yr market (before electricity crisis) but extremely significant for those in 2000 yr market (during the crisis). To further uncover the difference of asymmetry between the years 1999 and 2000, a modified H statistic (MH) and ΔMH statistic are proposed. One of the present contributions is that the high MH values calculated for hourly data exist in majority months in 2000 market. Another important conclusion is that the cross-correlation with downwards dominates over the whole 1999 yr in contrast to the cross-correlation with upwards dominates over the 2000 yr.

  12. The psychology of the 3D experience

    Science.gov (United States)

    Janicke, Sophie H.; Ellis, Andrew

    2013-03-01

    With 3D televisions expected to reach 50% home saturation as early as 2016, understanding the psychological mechanisms underlying the user response to 3D technology is critical for content providers, educators and academics. Unfortunately, research examining the effects of 3D technology has not kept pace with the technology's rapid adoption, resulting in large-scale use of a technology about which very little is actually known. Recognizing this need for new research, we conducted a series of studies measuring and comparing many of the variables and processes underlying both 2D and 3D media experiences. In our first study, we found narratives within primetime dramas had the power to shift viewer attitudes in both 2D and 3D settings. However, we found no difference in persuasive power between 2D and 3D content. We contend this lack of effect was the result of poor conversion quality and the unique demands of 3D production. In our second study, we found 3D technology significantly increased enjoyment when viewing sports content, yet offered no added enjoyment when viewing a movie trailer. The enhanced enjoyment of the sports content was shown to be the result of heightened emotional arousal and attention in the 3D condition. We believe the lack of effect found for the movie trailer may be genre-related. In our final study, we found 3D technology significantly enhanced enjoyment of two video games from different genres. The added enjoyment was found to be the result of an increased sense of presence.

  13. 3D Visualization Development of SIUE Campus

    Science.gov (United States)

    Nellutla, Shravya

    Geographic Information Systems (GIS) has progressed from the traditional map-making to the modern technology where the information can be created, edited, managed and analyzed. Like any other models, maps are simplified representations of real world. Hence visualization plays an essential role in the applications of GIS. The use of sophisticated visualization tools and methods, especially three dimensional (3D) modeling, has been rising considerably due to the advancement of technology. There are currently many off-the-shelf technologies available in the market to build 3D GIS models. One of the objectives of this research was to examine the available ArcGIS and its extensions for 3D modeling and visualization and use them to depict a real world scenario. Furthermore, with the advent of the web, a platform for accessing and sharing spatial information on the Internet, it is possible to generate interactive online maps. Integrating Internet capacity with GIS functionality redefines the process of sharing and processing the spatial information. Enabling a 3D map online requires off-the-shelf GIS software, 3D model builders, web server, web applications and client server technologies. Such environments are either complicated or expensive because of the amount of hardware and software involved. Therefore, the second objective of this research was to investigate and develop simpler yet cost-effective 3D modeling approach that uses available ArcGIS suite products and the free 3D computer graphics software for designing 3D world scenes. Both ArcGIS Explorer and ArcGIS Online will be used to demonstrate the way of sharing and distributing 3D geographic information on the Internet. A case study of the development of 3D campus for the Southern Illinois University Edwardsville is demonstrated.

  14. Semi- and virtual 3D dosimetry in clinical practice

    DEFF Research Database (Denmark)

    Korreman, S. S.

    2013-01-01

    In this review, 3D dosimetry is divided in three categories; "true" 3D, semi-3D and virtual 3D. Virtual 3D involves the use of measurement arrays either before or after beam entry in the patient/phantom, whereas semi-3D involves use of measurement arrays in phantoms mimicking the patient. True 3D...

  15. 3D facial expression modeling for recognition

    Science.gov (United States)

    Lu, Xiaoguang; Jain, Anil K.; Dass, Sarat C.

    2005-03-01

    Current two-dimensional image based face recognition systems encounter difficulties with large variations in facial appearance due to the pose, illumination and expression changes. Utilizing 3D information of human faces is promising for handling the pose and lighting variations. While the 3D shape of a face does not change due to head pose (rigid) and lighting changes, it is not invariant to the non-rigid facial movement and evolution, such as expressions and aging effect. We propose a facial surface matching framework to match multiview facial scans to a 3D face model, where the (non-rigid) expression deformation is explicitly modeled for each subject, resulting in a person-specific deformation model. The thin plate spline (TPS) is applied to model the deformation based on the facial landmarks. The deformation is applied to the 3D neutral expression face model to synthesize the corresponding expression. Both the neutral and the synthesized 3D surface models are used to match a test scan. The surface registration and matching between a test scan and a 3D model are achieved by a modified Iterative Closest Point (ICP) algorithm. Preliminary experimental results demonstrate that the proposed expression modeling and recognition-by-synthesis schemes improve the 3D matching accuracy.

  16. Medical 3D Printing for the Radiologist.

    Science.gov (United States)

    Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A; Cai, Tianrun; Kumamaru, Kanako K; George, Elizabeth; Wake, Nicole; Caterson, Edward J; Pomahac, Bohdan; Ho, Vincent B; Grant, Gerald T; Rybicki, Frank J

    2015-01-01

    While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article.

  17. Digital relief generation from 3D models

    Science.gov (United States)

    Wang, Meili; Sun, Yu; Zhang, Hongming; Qian, Kun; Chang, Jian; He, Dongjian

    2016-09-01

    It is difficult to extend image-based relief generation to high-relief generation, as the images contain insufficient height information. To generate reliefs from three-dimensional (3D) models, it is necessary to extract the height fields from the model, but this can only generate bas-reliefs. To overcome this problem, an efficient method is proposed to generate bas-reliefs and high-reliefs directly from 3D meshes. To produce relief features that are visually appropriate, the 3D meshes are first scaled. 3D unsharp masking is used to enhance the visual features in the 3D mesh, and average smoothing and Laplacian smoothing are implemented to achieve better smoothing results. A nonlinear variable scaling scheme is then employed to generate the final bas-reliefs and high-reliefs. Using the proposed method, relief models can be generated from arbitrary viewing positions with different gestures and combinations of multiple 3D models. The generated relief models can be printed by 3D printers. The proposed method provides a means of generating both high-reliefs and bas-reliefs in an efficient and effective way under the appropriate scaling factors.

  18. Detrended cross-correlations between returns, volatility, trading activity, and volume traded for the stock market companies

    Science.gov (United States)

    Rak, Rafał; Drożdż, Stanisław; Kwapień, Jarosław; Oświȩcimka, Paweł

    2015-11-01

    We consider a few quantities that characterize trading on a stock market in a fixed time interval: logarithmic returns, volatility, trading activity (i.e., the number of transactions), and volume traded. We search for the power-law cross-correlations among these quantities aggregated over different time units from 1 min to 10 min. Our study is based on empirical data from the American stock market consisting of tick-by-tick recordings of 31 stocks listed in Dow Jones Industrial Average during the years 2008-2011. Since all the considered quantities except the returns show strong daily patterns related to the variable trading activity in different parts of a day, which are the most evident in the autocorrelation function, we remove these patterns by detrending before we proceed further with our study. We apply the multifractal detrended cross-correlation analysis with sign preserving (MFCCA) and show that the strongest power-law cross-correlations exist between trading activity and volume traded, while the weakest ones exist (or even do not exist) between the returns and the remaining quantities. We also show that the strongest cross-correlations are carried by those parts of the signals that are characterized by large and medium variance. Our observation that the most convincing power-law cross-correlations occur between trading activity and volume traded reveals the existence of strong fractal-like coupling between these quantities.

  19. 3D Hilbert Space Filling Curves in 3D City Modeling for Faster Spatial Queries

    DEFF Research Database (Denmark)

    Ujang, Uznir; Antón Castro, Francesc/François; Azri, Suhaibah;

    2014-01-01

    objects. In this research, the authors propose an opponent data constellation technique of space-filling curves (3D Hilbert curves) for 3D city model data representation. Unlike previous methods, that try to project 3D or n-dimensional data down to 2D or 3D using Principal Component Analysis (PCA......) or Hilbert mappings, in this research, they extend the Hilbert space-filling curve to one higher dimension for 3D city model data implementations. The query performance was tested for single object, nearest neighbor and range search queries using a CityGML dataset of 1,000 building blocks and the results...... are presented in this paper. The advantages of implementing space-filling curves in 3D city modeling will improve data retrieval time by means of optimized 3D adjacency, nearest neighbor information and 3D indexing. The Hilbert mapping, which maps a sub-interval of the ([0,1]) interval to the corresponding...

  20. 3D Reconstruction Technique for Tomographic PIV

    Institute of Scientific and Technical Information of China (English)

    姜楠; 包全; 杨绍琼

    2015-01-01

    Tomographic particle image velocimetry(Tomo-PIV) is a state-of-the-art experimental technique based on a method of optical tomography to achieve the three-dimensional(3D) reconstruction for three-dimensional three-component(3D-3C) flow velocity measurements. 3D reconstruction for Tomo-PIV is carried out herein. Meanwhile, a 3D simplified tomographic reconstruction model reduced from a 3D volume light inten-sity field with 2D projection images into a 2D Tomo-slice plane with 1D projecting lines, i.e., simplifying this 3D reconstruction into a problem of 2D Tomo-slice plane reconstruction, is applied thereafter. Two kinds of the most well-known algebraic reconstruction techniques, algebraic reconstruction technique(ART) and multiple algebraic reconstruction technique(MART), are compared as well. The principles of the two reconstruction algorithms are discussed in detail, which has been performed by a series of simulation images, yielding the corresponding recon-struction images that show different features between the ART and MART algorithm, and then their advantages and disadvantages are discussed. Further discussions are made for the standard particle image reconstruction when the background noise of the pre-initial particle image has been removed. Results show that the particle image recon-struction has been greatly improved. The MART algorithm is much better than the ART. Furthermore, the computa-tional analyses of two parameters(the particle density and the number of cameras), are performed to study their effects on the reconstruction. Lastly, the 3D volume particle field is reconstructed by using the improved algorithm based on the simplified 3D tomographic reconstruction model, which proves that the algorithm simplification is feasible and it can be applied to the reconstruction of 3D volume particle field in a Tomo-PIV system.

  1. Extra Dimensions: 3D in PDF Documentation

    International Nuclear Information System (INIS)

    Experimental science is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) and the ISO PRC file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. Until recently, Adobe's Acrobat software was also capable of incorporating 3D content into PDF files from a variety of 3D file formats, including proprietary CAD formats. However, this functionality is no longer available in Acrobat X, having been spun off to a separate company. Incorporating 3D content now requires the additional purchase of a separate plug-in. In this talk we present alternatives based on open source libraries which allow the programmatic creation of 3D content in PDF format. While not providing the same level of access to CAD files as the commercial software, it does provide physicists with an alternative path to incorporate 3D content into PDF files from such disparate applications as detector geometries from Geant4, 3D data sets, mathematical surfaces or tesselated volumes.

  2. An Improved Version of TOPAZ 3D

    CERN Document Server

    Krasnykh, Anatoly K

    2003-01-01

    An improved version of the TOPAZ 3D gun code is presented as a powerful tool for beam optics simulation. In contrast to the previous version of TOPAZ 3D, the geometry of the device under test is introduced into TOPAZ 3D directly from a CAD program, such as Solid Edge or AutoCAD. In order to have this new feature, an interface was developed, using the GiD software package as a meshing code. The article describes this method with two models to illustrate the results.

  3. A high capacity 3D steganography algorithm.

    Science.gov (United States)

    Chao, Min-Wen; Lin, Chao-hung; Yu, Cheng-Wei; Lee, Tong-Yee

    2009-01-01

    In this paper, we present a very high-capacity and low-distortion 3D steganography scheme. Our steganography approach is based on a novel multilayered embedding scheme to hide secret messages in the vertices of 3D polygon models. Experimental results show that the cover model distortion is very small as the number of hiding layers ranges from 7 to 13 layers. To the best of our knowledge, this novel approach can provide much higher hiding capacity than other state-of-the-art approaches, while obeying the low distortion and security basic requirements for steganography on 3D models.

  4. 3D Printing the ATLAS' barrel toroid

    CERN Document Server

    Goncalves, Tiago Barreiro

    2016-01-01

    The present report summarizes my work as part of the Summer Student Programme 2016 in the CERN IR-ECO-TSP department (International Relations – Education, Communication & Outreach – Teacher and Student Programmes). Particularly, I worked closely with the S’Cool LAB team on a science education project. This project included the 3D designing, 3D printing, and assembling of a model of the ATLAS’ barrel toroid. A detailed description of the project' development is presented and a short manual on how to use 3D printing software and hardware is attached.

  5. Matching Feature Points in 3D World

    OpenAIRE

    Avdiu, Blerta

    2012-01-01

    This thesis work deals with the most actual topic in Computer Vision field which is scene understanding and this using matching of 3D feature point images. The objective is to make use of Saab’s latest breakthrough in extraction of 3D feature points, to identify the best alignment of at least two 3D feature point images. The thesis gives a theoretical overview of the latest algorithms used for feature detection, description and matching. The work continues with a brief description of the simu...

  6. Computer Modelling of 3D Geological Surface

    CERN Document Server

    Kodge, B G

    2011-01-01

    The geological surveying presently uses methods and tools for the computer modeling of 3D-structures of the geographical subsurface and geotechnical characterization as well as the application of geoinformation systems for management and analysis of spatial data, and their cartographic presentation. The objectives of this paper are to present a 3D geological surface model of Latur district in Maharashtra state of India. This study is undertaken through the several processes which are discussed in this paper to generate and visualize the automated 3D geological surface model of a projected area.

  7. General Concept of 3D SLAM

    OpenAIRE

    Zhang, Peter; Millos, Evangelous; Gu, Jason

    2009-01-01

    This chapter established an approach to solve the full 3D SLAM problem, applied to an underwater environment. First, a general approach to the 3D SLAM problem was presented, which included the models in 3D case, data association and estimation algorithm. For an underwater mobile robot, a new measurement system was designed for large area's globally-consistent SLAM: buoys for long-range estimation, and camera for short-range estimation and map building. Globally-consistent results could be obt...

  8. The reactor dynamics code DYN3D

    Energy Technology Data Exchange (ETDEWEB)

    Kliem, Soeren; Bilodid, Yuri; Fridman, Emil; Baier, Silvio; Grahn, Alexander; Gommlich, Andre; Nikitin, Evgeny; Rohde, Ulrich [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany)

    2016-05-15

    The article provides an overview on the code DYN3D which is a three-dimensional core model for steady-state, dynamic and depletion calculations in reactor cores with quadratic or hexagonal fuel assembly geometry being developed by the Helmholtz-Zentrum Dresden-Rossendorf for more than 20 years. The current paper gives an overview on the basic DYN3D models and the available code couplings. The verification and validation status is shortly outlined. The paper concludes with the current developments of the DYN3D code. For more detailed information the reader is referred to the publications cited in the corresponding chapters.

  9. 3D background aerodynamics using CFD

    DEFF Research Database (Denmark)

    Sørensen, Niels N.

    2002-01-01

    3D rotor computations for the Greek Geovilogiki (GEO) 44 meter rotor equipped with 19 meters blades are performed. The lift and drag polars are extracted at five spanvise locations r/R= (.37, .55, .71, .82, .93) based on identification of stagnationpoints between 2D and 3D computations. The inner...... most sections shows clear evidence of 3D radial pumping, with increased lift compared to 2D values. In contrast to earlier investigated airfoils a very limited impact on the drag values are observed....

  10. 3D tulostus - digitaalisesta mallista esineeksi

    OpenAIRE

    Muurinen, Kimmo

    2013-01-01

    Tässä opinnäytetyössä esitellään 3D tulostuksen tekniikka ja materiaaleja, suunnitellaan ja tuotetaan esimerkkikappaleen digitaalinen malli, sekä tulostetaan muovinen esine digi-taalisen mallin pohjalta. Työn tavoitteena on perehdyttää lukija prosessiin, jossa itse tuotettu digitaalinen malli tulostetaan käyttäen harrastajakäyttöön tarkoitettua edullista 3D tulostinta. Esimerkkikappaleen eri osien mallinnusprosessi näytetään kokonaisuudessaan ja kerro-taan perusteita 3D mallinnuksesta...

  11. Automatic balancing of 3D models

    DEFF Research Database (Denmark)

    Christiansen, Asger Nyman; Schmidt, Ryan; Bærentzen, Jakob Andreas

    2014-01-01

    3D printing technologies allow for more diverse shapes than are possible with molds and the cost of making just one single object is negligible compared to traditional production methods. However, not all shapes are suitable for 3D print. One of the remaining costs is therefore human time spent......, in these cases, we will apply a rotation of the object which only deforms the shape a little near the base. No user input is required but it is possible to specify manufacturing constraints related to specific 3D print technologies. Several models have successfully been balanced and printed using both polyjet...

  12. An Improved Version of TOPAZ 3D

    International Nuclear Information System (INIS)

    An improved version of the TOPAZ 3D gun code is presented as a powerful tool for beam optics simulation. In contrast to the previous version of TOPAZ 3D, the geometry of the device under test is introduced into TOPAZ 3D directly from a CAD program, such as Solid Edge or AutoCAD. In order to have this new feature, an interface was developed, using the GiD software package as a meshing code. The article describes this method with two models to illustrate the results

  13. FIT3D: Fitting optical spectra

    Science.gov (United States)

    Sánchez, S. F.; Pérez, E.; Sánchez-Blázquez, P.; González, J. J.; Rosales-Ortega, F. F.; Cano-Díaz, M.; López-Cobá, C.; Marino, R. A.; Gil de Paz, A.; Mollá, M.; López-Sánchez, A. R.; Ascasibar, Y.; Barrera-Ballesteros, J.

    2016-09-01

    FIT3D fits optical spectra to deblend the underlying stellar population and the ionized gas, and extract physical information from each component. FIT3D is focused on the analysis of Integral Field Spectroscopy data, but is not restricted to it, and is the basis of Pipe3D, a pipeline used in the analysis of datasets like CALIFA, MaNGA, and SAMI. It can run iteratively or in an automatic way to derive the parameters of a large set of spectra.

  14. FUN3D Manual: 12.5

    Science.gov (United States)

    Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, William L.; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.

    2014-01-01

    This manual describes the installation and execution of FUN3D version 12.5, including optional dependent packages. FUN3D is a suite of computational uid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables ecient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  15. FUN3D Manual: 13.0

    Science.gov (United States)

    Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bill; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.

    2016-01-01

    This manual describes the installation and execution of FUN3D version 13.0, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  16. FUN3D Manual: 12.9

    Science.gov (United States)

    Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.

    2016-01-01

    This manual describes the installation and execution of FUN3D version 12.9, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  17. FUN3D Manual: 12.4

    Science.gov (United States)

    Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.

    2014-01-01

    This manual describes the installation and execution of FUN3D version 12.4, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixedelement unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  18. 3D grafika a hry

    OpenAIRE

    Vataščinová, Lenka

    2016-01-01

    In my bachelor thesis, I am going to introduce the topic of 3D graphics in the game environment. Firstly, I will provide a brief introduction of history of 3D graphics in general, but with the emphasis on history of game industry in particular. Next, I will present 3D graphics of RPG games in particular, and I will analyse the graphical side of digital work production. The main contribution of this thesis is provided in the practical part, which deals with creation of an environment for an an...

  19. 3-D Human Modeling and Animation

    CERN Document Server

    Ratner, Peter

    2012-01-01

    3-D Human Modeling and Animation Third Edition All the tools and techniques you need to bring human figures to 3-D life Thanks to today's remarkable technology, artists can create and animate realistic, three-dimensional human figures that were not possible just a few years ago. This easy-to-follow book guides you through all the necessary steps to adapt your own artistic skill in figure drawing, painting, and sculpture to this exciting digital canvas. 3-D Human Modeling and Animation, Third Edition starts you off with simple modeling, then prepares you for more advanced techniques for crea

  20. 3D face modeling, analysis and recognition

    CERN Document Server

    Daoudi, Mohamed; Veltkamp, Remco

    2013-01-01

    3D Face Modeling, Analysis and Recognition presents methodologies for analyzing shapes of facial surfaces, develops computational tools for analyzing 3D face data, and illustrates them using state-of-the-art applications. The methodologies chosen are based on efficient representations, metrics, comparisons, and classifications of features that are especially relevant in the context of 3D measurements of human faces. These frameworks have a long-term utility in face analysis, taking into account the anticipated improvements in data collection, data storage, processing speeds, and application s

  1. The reactor dynamics code DYN3D

    International Nuclear Information System (INIS)

    The article provides an overview on the code DYN3D which is a three-dimensional core model for steady-state, dynamic and depletion calculations in reactor cores with quadratic or hexagonal fuel assembly geometry being developed by the Helmholtz-Zentrum Dresden-Rossendorf for more than 20 years. The current paper gives an overview on the basic DYN3D models and the available code couplings. The verification and validation status is shortly outlined. The paper concludes with the current developments of the DYN3D code. For more detailed information the reader is referred to the publications cited in the corresponding chapters.

  2. 3D-hahmojen toteutus mobiilipeliin

    OpenAIRE

    Kemppainen, Matti

    2012-01-01

    Mobiilipelien suosio on kasvanut räjähdysmäisesti viime vuosina älypuhelinten kehittymisen myötä. Tässä opinnäytetyössä selvitetään kolmiulotteisen pelihahmon toteutusprosessi mobiilipeliin. Lisäksi pohditaan maksullisten ja ilmaisten ohjelmien eroja toteutuksessa. Pelihahmojen toteutus perustuu mobiilipeliprojektiin peliyrityksessä, jossa työskentelin graafikkona. Ohjelmien vertailussa on mukana 3D Studio Max, Blender 3D, Photoshop ja GIMP. Käytännön osuudessa käydään läpi 3D-pelihahmon...

  3. 3D-MR cholangio-angiography

    Energy Technology Data Exchange (ETDEWEB)

    Ohkawa, Shinichi [Isehara Kyohdoh Hospital, Kanagawa (Japan); Hiramatsu, Kyoichi

    1995-04-01

    This report introduces a new 3D-MR cholangio-angiography technique using 3D Fast SE MR cholangiography and 3D phase contrast MR angiography for obstructive jaundice. In all eight cases, dilated biliary tracts as well as portal veins were clearly visualized in the same image. This new technique helped to determine the operability and surgical strategy for cases with obstructive jaundice. It also provided anatomical guidance for surgical procedures. This study suggests that this technique may replace the currently used modalities for obstructive jaundice. (author).

  4. Knowledge Transfer from Detailed 3-D CFD Codes to System Simulation Tools – CCV Modeling in SI Engine

    Directory of Open Access Journals (Sweden)

    Vítek Oldřich

    2016-06-01

    Full Text Available The paper deals with CCV knowledge transfer from reference data (either experiments or 3-D CFD data into system simulation SW tools (based on 0-D/1-D CFD. It was verified that CCV phenomenon can be modeled by means of combustion model perturbations. The proposed methodology consists of two major steps. First, individual cycle data have to be matched with the 0-D/1-D model, i.e., combustion model parameters are varied to achieve the best possible match of in-cylinder pressure traces. Second, the combustion model parameters (obtained in previous step are statistically evaluated to obtain PDFs and cross-correlations. Then such information is imposed to the 0-D/1-D tool to mimic pressure traces CCV. Good correspondence with the reference data is achieved only if both PDFs and cross-correlations are imposed simultaneously.

  5. The 3D Object Mediator : Handling 3D Models on Internet

    NARCIS (Netherlands)

    Kok, A.J.F.; Lawick van Pabst, J. van; Afsarmanesh, H.

    1997-01-01

    The 3D Object MEdiator (3DOME 3) offers two services for handling 3D models: a modelshop and a renderfarm. These services can be consulted through the Internet. The modelshop meets the demands for brokerage of geometric descriptions of 3D models. People who create geometric models of objects can sup

  6. XML3D and Xflow: combining declarative 3D for the Web with generic data flows.

    Science.gov (United States)

    Klein, Felix; Sons, Kristian; Rubinstein, Dmitri; Slusallek, Philipp

    2013-01-01

    Researchers have combined XML3D, which provides declarative, interactive 3D scene descriptions based on HTML5, with Xflow, a language for declarative, high-performance data processing. The result lets Web developers combine a 3D scene graph with data flows for dynamic meshes, animations, image processing, and postprocessing. PMID:24808080

  7. 3D presentatie van geluid in de cockpit [3D sound presentation in the cockpit

    NARCIS (Netherlands)

    Bronkhorst, A.W.

    2003-01-01

    A.W. Bronkhorst, 3D-presentatie van geluid in de cockpit 1 Using virtual acoustics, sound can be presented from virtual sources located in the 3D space around the listener. This 3D sound has interesting applications in the cockpit. Sounds can be used to convey directional information, and interferen

  8. Do-It-Yourself: 3D Models of Hydrogenic Orbitals through 3D Printing

    Science.gov (United States)

    Griffith, Kaitlyn M.; de Cataldo, Riccardo; Fogarty, Keir H.

    2016-01-01

    Introductory chemistry students often have difficulty visualizing the 3-dimensional shapes of the hydrogenic electron orbitals without the aid of physical 3D models. Unfortunately, commercially available models can be quite expensive. 3D printing offers a solution for producing models of hydrogenic orbitals. 3D printing technology is widely…

  9. Intensity Correlation Function of a Single-Mode Laser Driven by Two Colored Noises with Colored Cross-Correlation

    Institute of Scientific and Technical Information of China (English)

    HANLi-Bo; CAOLi; WUDa-Jin; WANGJun

    2004-01-01

    By using the linear approximation method, the intensity correlation function and the intensity correlation time are calculated in a gain-noise model of a single-mode laser driven by colored cross-correlated pump noise and quantum noise, each of which is colored. We detect that, when the cross-correlation between both noises is negative, the behavior of the intensity correlation function C(t) versus time t, in addition to decreasing monotonously, also exhibits several other cases, such as one maximum, one minimum, and two extrema (one maximum and one minimum), i.e., some parameters of the noises can greatly change the dependence of the intensity correlation function upon time. Moreover, we find that there is a minimum Tmin in the curve of the intensity correlation time versus the pump noise intensity, and the depth and position of Train strongly depend on the quantum noise self-correlation time T2 and cross-correlation time T3.

  10. Lightning fast animation in Element 3D

    CERN Document Server

    Audronis, Ty

    2014-01-01

    An easy-to-follow and all-inclusive guide, in which the underlying principles of 3D animation as well as their importance are explained in detail. The lessons are designed to teach you how to think of 3D animation in such a way that you can troubleshoot any problem, or animate any scene that comes your way.If you are a Digital Artist, Animation Artist, or a Game Programmer and you want to become an expert in Element 3D, this is the book for you. Although there are a lot of basics for beginners in this book, it includes some advanced techniques for both animating in Element 3D, and overcoming i

  11. Eyes on the Earth 3D

    Science.gov (United States)

    Kulikov, anton I.; Doronila, Paul R.; Nguyen, Viet T.; Jackson, Randal K.; Greene, William M.; Hussey, Kevin J.; Garcia, Christopher M.; Lopez, Christian A.

    2013-01-01

    Eyes on the Earth 3D software gives scientists, and the general public, a realtime, 3D interactive means of accurately viewing the real-time locations, speed, and values of recently collected data from several of NASA's Earth Observing Satellites using a standard Web browser (climate.nasa.gov/eyes). Anyone with Web access can use this software to see where the NASA fleet of these satellites is now, or where they will be up to a year in the future. The software also displays several Earth Science Data sets that have been collected on a daily basis. This application uses a third-party, 3D, realtime, interactive game engine called Unity 3D to visualize the satellites and is accessible from a Web browser.

  12. 3D Flash LIDAR Space Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc (ASC) is a small business, which has developed a compact, eye-safe 3D Flash LIDARTM Camera (FLC) well suited for real-time...

  13. 3D-FPA Hybridization Improvements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc. (ASC) is a small business, which has developed a compact, eye-safe 3D Flash LIDARTM Camera (FLC) well suited for real-time...

  14. Copper Electrodeposition for 3D Integration

    CERN Document Server

    Beica, Rozalia; Ritzdorf, Tom

    2008-01-01

    Two dimensional (2D) integration has been the traditional approach for IC integration. Due to increasing demands for providing electronic devices with superior performance and functionality in more efficient and compact packages, has driven the semiconductor industry to develop more advanced packaging technologies. Three-dimensional (3D) approaches address both miniaturization and integration required for advanced and portable electronic products. Vertical integration proved to be essential in achieving a greater integration flexibility of disparate technologies, reason for which a general trend of transition from 2D to 3D integration is currently being observed in the industry. 3D chip integration using through silicon via (TSV) copper is considered one of the most advanced technologies among all different types of 3D packaging technologies. Copper electrodeposition is one of technologies that enable the formation of TSV structures. Because of its well-known application for copper damascene, it was believed ...

  15. 3D Biomaterial Microarrays for Regenerative Medicine

    DEFF Research Database (Denmark)

    Gaharwar, Akhilesh K.; Arpanaei, Ayyoob; Andresen, Thomas Lars;

    2015-01-01

    Three dimensional (3D) biomaterial microarrays hold enormous promise for regenerative medicine because of their ability to accelerate the design and fabrication of biomimetic materials. Such tissue-like biomaterials can provide an appropriate microenvironment for stimulating and controlling stem...

  16. 3DSEM: A 3D microscopy dataset.

    Science.gov (United States)

    Tafti, Ahmad P; Kirkpatrick, Andrew B; Holz, Jessica D; Owen, Heather A; Yu, Zeyun

    2016-03-01

    The Scanning Electron Microscope (SEM) as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples. PMID:26779561

  17. 3DSEM: A 3D microscopy dataset

    Directory of Open Access Journals (Sweden)

    Ahmad P. Tafti

    2016-03-01

    Full Text Available The Scanning Electron Microscope (SEM as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples.

  18. 3D Visualization of Recent Sumatra Earthquake

    Science.gov (United States)

    Nayak, Atul; Kilb, Debi

    2005-04-01

    Scientists and visualization experts at the Scripps Institution of Oceanography have created an interactive three-dimensional visualization of the 28 March 2005 magnitude 8.7 earthquake in Sumatra. The visualization shows the earthquake's hypocenter and aftershocks recorded until 29 March 2005, and compares it with the location of the 26 December 2004 magnitude 9 event and the consequent seismicity in that region. The 3D visualization was created using the Fledermaus software developed by Interactive Visualization Systems (http://www.ivs.unb.ca/) and stored as a ``scene'' file. To view this visualization, viewers need to download and install the free viewer program iView3D (http://www.ivs3d.com/products/iview3d).

  19. 3D VISUALIZATION FOR VIRTUAL MUSEUM DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    M. Skamantzari

    2016-06-01

    Full Text Available The interest in the development of virtual museums is nowadays rising rapidly. During the last decades there have been numerous efforts concerning the 3D digitization of cultural heritage and the development of virtual museums, digital libraries and serious games. The realistic result has always been the main concern and a real challenge when it comes to 3D modelling of monuments, artifacts and especially sculptures. This paper implements, investigates and evaluates the results of the photogrammetric methods and 3D surveys that were used for the development of a virtual museum. Moreover, the decisions, the actions, the methodology and the main elements that this kind of application should include and take into consideration are described and analysed. It is believed that the outcomes of this application will be useful to researchers who are planning to develop and further improve the attempts made on virtual museums and mass production of 3D models.

  20. Cubical Cohomology Ring of 3D Photographs

    CERN Document Server

    Gonzalez-Diaz, Rocio; Medrano, Belen; 10.1002/ima.20271

    2011-01-01

    Cohomology and cohomology ring of three-dimensional (3D) objects are topological invariants that characterize holes and their relations. Cohomology ring has been traditionally computed on simplicial complexes. Nevertheless, cubical complexes deal directly with the voxels in 3D images, no additional triangulation is necessary, facilitating efficient algorithms for the computation of topological invariants in the image context. In this paper, we present formulas to directly compute the cohomology ring of 3D cubical complexes without making use of any additional triangulation. Starting from a cubical complex $Q$ that represents a 3D binary-valued digital picture whose foreground has one connected component, we compute first the cohomological information on the boundary of the object, $\\partial Q$ by an incremental technique; then, using a face reduction algorithm, we compute it on the whole object; finally, applying the mentioned formulas, the cohomology ring is computed from such information.

  1. Networked 3D Virtual Museum System

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Virtual heritage has become increasingly important in the conservation, preservation, and interpretation of our cultural and natural history. Moreover, rapid advances in digital technologies in recent years offer virtual heritage new direction. This paper introduces our approach toward a networked 3D virtual museum system, especially, how to model, manage, present virtual heritages and furthermore how to use computer network for the share of virtual heritage in the networked virtual environment. This paper first addresses a 3D acquisition and processing technique for virtual heritage modeling and shows some illustrative examples. Then, this paper describes a management of virtual heritage assets that are composed by various rich media. This paper introduces our schemes to present the virtual heritages, which include 3D virtual heritage browser system, CAVE system, and immersive VR theater. Finally, this paper presents the new direction of networked 3D virtual museum of which main idea is remote guide of the virtual heritage using the mixed reality technique.

  2. High accuracy 3-D laser radar

    DEFF Research Database (Denmark)

    Busck, Jens; Heiselberg, Henning

    2004-01-01

    We have developed a mono-static staring 3-D laser radar based on gated viewing with range accuracy below 1 m at 10 m and 1 cm at 100. We use a high sensitivity, fast, intensified CCD camera, and a Nd:Yag passively Q-switched 32.4 kHz pulsed green laser at 532 nm. The CCD has 752x582 pixels. Camera...... shutter is controlled in steps of 100 ps. Camera delay is controlled in steps of 100 ps. Each laser pulse triggers the camera delay and shutter. A 3-D image is constructed from a sequence of 50-100 2-D reflectivity images, where each frame integrates about 700 laser pulses on the CCD. In 50 Hz video mode...... we record a 2-D sequence in a second and process a 3-D image in few seconds. We compare 3-D images with a system performance model....

  3. Nonlaser-based 3D surface imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shin-yee; Johnson, R.K.; Sherwood, R.J. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    3D surface imaging refers to methods that generate a 3D surface representation of objects of a scene under viewing. Laser-based 3D surface imaging systems are commonly used in manufacturing, robotics and biomedical research. Although laser-based systems provide satisfactory solutions for most applications, there are situations where non laser-based approaches are preferred. The issues that make alternative methods sometimes more attractive are: (1) real-time data capturing, (2) eye-safety, (3) portability, and (4) work distance. The focus of this presentation is on generating a 3D surface from multiple 2D projected images using CCD cameras, without a laser light source. Two methods are presented: stereo vision and depth-from-focus. Their applications are described.

  4. Tvorba 3D modelů

    OpenAIRE

    Musálek, Martin

    2014-01-01

    Práce řeší 3D rekonstrukci objektu pomocí metody nasvícení vzorem. Projektor nasvěcuje měřený objekt definovaným vzorem a dvojice kamer z něj snímá body. Podstavec s objektem se otáčí, a během více měření je objekt sejmut z více úhlů. Body jsou identifikovány z naměřených snímků, transformovány na 3D pomocí stereovidění, spojeny do 3D modelu a zobrazeny. Thesis solves 3D reconstruction of an object by method of lighting by pattern. A projector lights the measured object by defined pattern ...

  5. 3D Maps Representation Using GNG

    Directory of Open Access Journals (Sweden)

    Vicente Morell

    2014-01-01

    Full Text Available Current RGB-D sensors provide a big amount of valuable information for mobile robotics tasks like 3D map reconstruction, but the storage and processing of the incremental data provided by the different sensors through time quickly become unmanageable. In this work, we focus on 3D maps representation and propose the use of the Growing Neural Gas (GNG network as a model to represent 3D input data. GNG method is able to represent the input data with a desired amount of neurons or resolution while preserving the topology of the input space. Experiments show how GNG method yields a better input space adaptation than other state-of-the-art 3D map representation methods.

  6. 3D-printed bioanalytical devices

    Science.gov (United States)

    Bishop, Gregory W.; Satterwhite-Warden, Jennifer E.; Kadimisetty, Karteek; Rusling, James F.

    2016-07-01

    While 3D printing technologies first appeared in the 1980s, prohibitive costs, limited materials, and the relatively small number of commercially available printers confined applications mainly to prototyping for manufacturing purposes. As technologies, printer cost, materials, and accessibility continue to improve, 3D printing has found widespread implementation in research and development in many disciplines due to ease-of-use and relatively fast design-to-object workflow. Several 3D printing techniques have been used to prepare devices such as milli- and microfluidic flow cells for analyses of cells and biomolecules as well as interfaces that enable bioanalytical measurements using cellphones. This review focuses on preparation and applications of 3D-printed bioanalytical devices.

  7. Advanced 3D Object Identification System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Optra will build an Advanced 3D Object Identification System utilizing three or more high resolution imagers spaced around a launch platform. Data from each imager...

  8. Measuring Visual Closeness of 3-D Models

    KAUST Repository

    Morales, Jose A.

    2012-09-01

    Measuring visual closeness of 3-D models is an important issue for different problems and there is still no standardized metric or algorithm to do it. The normal of a surface plays a vital role in the shading of a 3-D object. Motivated by this, we developed two applications to measure visualcloseness, introducing normal difference as a parameter in a weighted metric in Metro’s sampling approach to obtain the maximum and mean distance between 3-D models using 3-D and 6-D correspondence search structures. A visual closeness metric should provide accurate information on what the human observers would perceive as visually close objects. We performed a validation study with a group of people to evaluate the correlation of our metrics with subjective perception. The results were positive since the metrics predicted the subjective rankings more accurately than the Hausdorff distance.

  9. Transportstromen verschuiven door toepassing 3-D

    NARCIS (Netherlands)

    Janssen, G.R.

    2014-01-01

    3-D printing is aan een gestage opmars bezig.ln een paar jaar tijd is er een miljardenmarkt ontstaan die exponentieel groeit. TNO deed onderzoek naar de impact van deze ontwikkelingen op supply chains.

  10. Pentingnya Pengetahuan Anatomi untuk 3D Artist

    Directory of Open Access Journals (Sweden)

    Anton Sugito Kurniawan

    2011-03-01

    Full Text Available No matter how far the current technological advances, anatomical knowledge will still be needed as a basis for making a good character design. Understanding anatomy will help us in the placement of the articulation of muscles and joints, thus more realistic modeling of 3d characters will be achieved in the form and movement. As a 3d character artist, anatomy should be able to inform in every aspect of our work. Each 3D/CG (Computer Graphics-artist needs to know how to use software applications, but what differentiates a 3d artist with a computer operator is an artistic vision and understanding of the basic shape of the human body. Artistic vision could not easily be taught, but a CG-artist may study it on their own from which so many reference sources may help understand and deepen their knowledge of anatomy.

  11. BER Analysis Using Beat Probability Method of 3D Optical CDMA Networks with Double Balanced Detection

    Directory of Open Access Journals (Sweden)

    Chih-Ta Yen

    2015-01-01

    Full Text Available This study proposes novel three-dimensional (3D matrices of wavelength/time/spatial code for code-division multiple-access (OCDMA networks, with a double balanced detection mechanism. We construct 3D carrier-hopping prime/modified prime (CHP/MP codes by extending a two-dimensional (2D CHP code integrated with a one-dimensional (1D MP code. The corresponding coder/decoder pairs were based on fiber Bragg gratings (FBGs and tunable optical delay lines integrated with splitters/combiners. System performance was enhanced by the low cross correlation properties of the 3D code designed to avoid the beat noise phenomenon. The CHP/MP code cardinality increased significantly compared to the CHP code under the same bit error rate (BER. The results indicate that the 3D code method can enhance system performance because both the beating terms and multiple-access interference (MAI were reduced by the double balanced detection mechanism. Additionally, the optical component can also be relaxed for high transmission scenery.

  12. 3D nonrigid medical image registration using a new information theoretic measure

    International Nuclear Information System (INIS)

    This work presents a novel method for the nonrigid registration of medical images based on the Arimoto entropy, a generalization of the Shannon entropy. The proposed method employed the Jensen–Arimoto divergence measure as a similarity metric to measure the statistical dependence between medical images. Free-form deformations were adopted as the transformation model and the Parzen window estimation was applied to compute the probability distributions. A penalty term is incorporated into the objective function to smooth the nonrigid transformation. The goal of registration is to optimize an objective function consisting of a dissimilarity term and a penalty term, which would be minimal when two deformed images are perfectly aligned using the limited memory BFGS optimization method, and thus to get the optimal geometric transformation. To validate the performance of the proposed method, experiments on both simulated 3D brain MR images and real 3D thoracic CT data sets were designed and performed on the open source elastix package. For the simulated experiments, the registration errors of 3D brain MR images with various magnitudes of known deformations and different levels of noise were measured. For the real data tests, four data sets of 4D thoracic CT from four patients were selected to assess the registration performance of the method, including ten 3D CT images for each 4D CT data covering an entire respiration cycle. These results were compared with the normalized cross correlation and the mutual information methods and show a slight but true improvement in registration accuracy. (paper)

  13. 3D nonrigid medical image registration using a new information theoretic measure

    Science.gov (United States)

    Li, Bicao; Yang, Guanyu; Coatrieux, Jean Louis; Li, Baosheng; Shu, Huazhong

    2015-11-01

    This work presents a novel method for the nonrigid registration of medical images based on the Arimoto entropy, a generalization of the Shannon entropy. The proposed method employed the Jensen-Arimoto divergence measure as a similarity metric to measure the statistical dependence between medical images. Free-form deformations were adopted as the transformation model and the Parzen window estimation was applied to compute the probability distributions. A penalty term is incorporated into the objective function to smooth the nonrigid transformation. The goal of registration is to optimize an objective function consisting of a dissimilarity term and a penalty term, which would be minimal when two deformed images are perfectly aligned using the limited memory BFGS optimization method, and thus to get the optimal geometric transformation. To validate the performance of the proposed method, experiments on both simulated 3D brain MR images and real 3D thoracic CT data sets were designed and performed on the open source elastix package. For the simulated experiments, the registration errors of 3D brain MR images with various magnitudes of known deformations and different levels of noise were measured. For the real data tests, four data sets of 4D thoracic CT from four patients were selected to assess the registration performance of the method, including ten 3D CT images for each 4D CT data covering an entire respiration cycle. These results were compared with the normalized cross correlation and the mutual information methods and show a slight but true improvement in registration accuracy.

  14. Embedding 3D into multipurpose cadastre

    OpenAIRE

    A. A. Rahman; T. C. Hua; P. J. M. Van Oosterom

    2011-01-01

    There is no doubt that the cadastral map provides a useful entrance to information in a land parcel based information system. However, such information system could be made more meaningful and useful if it can be extended for multiple usages with multi data layers, and in three-dimensions (3D). Currently, many national mapping and cadastral agencies (NMCAs) and users deal with complex situations, and we believe that 3D could enhance the understanding of the situations better. This paper descr...

  15. Luovasta konseptisuunnittelusta 3D-mainoselokuvaan

    OpenAIRE

    Salo, Suvi

    2015-01-01

    Insinöörityön tavoite oli luoda 3D-mainoselokuva myynnin tueksi ja nostaa esiin IT-alan yrityksen ja sen yksikön tuottamien palveluiden laajuutta ja yrityksen tapaa tuottaa tulostuspalvelua. Toteutettu mainoselokuva on tarkoitettu julkaistavaksi verkossa yrityksen omalla Youtube-kanavalla ja verkkosivuilla. 3D-mainoselokuvan suunnittelussa käytettiin luovan konseptisuunnittelun keinoja jalostaa tarina kohderyhmälähtöiseksi. Aluksi selvitettiin asiakasrajapinnan haastattelujen avulla kohde...

  16. 3D printing: technology and processing

    OpenAIRE

    Kurinov, Ilya

    2016-01-01

    The objective of the research was to improve the process of 3D printing on the laboratory machine. In the study processes of designing, printing and post-print-ing treatment were improved. The study was commissioned by Mikko Ruotsalainen, head of the laboratory. The data was collected during the test work. All the basic information about 3D printing was taken from the Internet or library. As the results of the project higher model accuracy, solutions for post-printing treatment, printin...

  17. The Idaho Virtualization Laboratory 3D Pipeline

    Directory of Open Access Journals (Sweden)

    Nicholas A. Holmer

    2014-05-01

    Full Text Available Three dimensional (3D virtualization and visualization is an important component of industry, art, museum curation and cultural heritage, yet the step by step process of 3D virtualization has been little discussed. Here we review the Idaho Virtualization Laboratory’s (IVL process of virtualizing a cultural heritage item (artifact from start to finish. Each step is thoroughly explained and illustrated including how the object and its metadata are digitally preserved and ultimately distributed to the world.

  18. 3D Printing for Tissue Engineering

    OpenAIRE

    Richards, Dylan Jack; Tan, Yu; Jia, Jia; Yao, Hai; Mei, Ying

    2013-01-01

    Tissue engineering aims to fabricate functional tissue for applications in regenerative medicine and drug testing. More recently, 3D printing has shown great promise in tissue fabrication with a structural control from micro- to macro-scale by using a layer-by-layer approach. Whether through scaffold-based or scaffold-free approaches, the standard for 3D printed tissue engineering constructs is to provide a biomimetic structural environment that facilitates tissue formation and promotes host ...

  19. 3D Printing Electrically Small Spherical Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2013-01-01

    3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations.......3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations....

  20. LandSIM3D: modellazione in real time 3D di dati geografici

    OpenAIRE

    Lambo Srl Lambo Srl

    2009-01-01

    LandSIM3D: realtime 3D modelling of geographic dataLandSIM3D allows to model in 3D an existing landscape in a few hours only and geo-referenced offering great landscape analysis and understanding tools. 3D projects can then be inserted into the existing landscape with ease and precision. The project alternatives and impact can then be visualized and studied into their immediate environmental. The complex evolution of the landscape in the future can also be simulated and the landscape model ca...

  1. ASSESSING 3D PHOTOGRAMMETRY TECHNIQUES IN CRANIOMETRICS

    Directory of Open Access Journals (Sweden)

    M. C. Moshobane

    2016-06-01

    Full Text Available Morphometrics (the measurement of morphological features has been revolutionized by the creation of new techniques to study how organismal shape co-varies with several factors such as ecophenotypy. Ecophenotypy refers to the divergence of phenotypes due to developmental changes induced by local environmental conditions, producing distinct ecophenotypes. None of the techniques hitherto utilized could explicitly address organismal shape in a complete biological form, i.e. three-dimensionally. This study investigates the use of the commercial software, Photomodeler Scanner® (PMSc® three-dimensional (3D modelling software to produce accurate and high-resolution 3D models. Henceforth, the modelling of Subantarctic fur seal (Arctocephalus tropicalis and Antarctic fur seal (Arctocephalus gazella skulls which could allow for 3D measurements. Using this method, sixteen accurate 3D skull models were produced and five metrics were determined. The 3D linear measurements were compared to measurements taken manually with a digital caliper. In addition, repetitive measurements were recorded by varying researchers to determine repeatability. To allow for comparison straight line measurements were taken with the software, assuming that close accord with all manually measured features would illustrate the model’s accurate replication of reality. Measurements were not significantly different demonstrating that realistic 3D skull models can be successfully produced to provide a consistent basis for craniometrics, with the additional benefit of allowing non-linear measurements if required.

  2. Assessing 3d Photogrammetry Techniques in Craniometrics

    Science.gov (United States)

    Moshobane, M. C.; de Bruyn, P. J. N.; Bester, M. N.

    2016-06-01

    Morphometrics (the measurement of morphological features) has been revolutionized by the creation of new techniques to study how organismal shape co-varies with several factors such as ecophenotypy. Ecophenotypy refers to the divergence of phenotypes due to developmental changes induced by local environmental conditions, producing distinct ecophenotypes. None of the techniques hitherto utilized could explicitly address organismal shape in a complete biological form, i.e. three-dimensionally. This study investigates the use of the commercial software, Photomodeler Scanner® (PMSc®) three-dimensional (3D) modelling software to produce accurate and high-resolution 3D models. Henceforth, the modelling of Subantarctic fur seal (Arctocephalus tropicalis) and Antarctic fur seal (Arctocephalus gazella) skulls which could allow for 3D measurements. Using this method, sixteen accurate 3D skull models were produced and five metrics were determined. The 3D linear measurements were compared to measurements taken manually with a digital caliper. In addition, repetitive measurements were recorded by varying researchers to determine repeatability. To allow for comparison straight line measurements were taken with the software, assuming that close accord with all manually measured features would illustrate the model's accurate replication of reality. Measurements were not significantly different demonstrating that realistic 3D skull models can be successfully produced to provide a consistent basis for craniometrics, with the additional benefit of allowing non-linear measurements if required.

  3. Effects of cross-correlated noises on the intensity fluctuation of the single-mode laser system

    Institute of Scientific and Technical Information of China (English)

    Bing Wang; Shuwen Dai; Shuping Ge

    2006-01-01

    @@ A single-mode laser model with cross-correlated additive and multiplicative noise terms is considered, and the effects of correlation between noises on the relaxation time and the intensity correlation function are studied. Using the projection operator method and taking into account the effects of the memory kernels of the intensity correlation function, the analytic expressions for the relaxation time and the correlation function are derived. Based on numerical computations, it is found that the self-correlation time and the cross-correlation time have the same effects on the single-mode laser system.

  4. Measurements of V/STOL aircraft noise mechanisms using pressure cross-correlation techniques in a reverberant wind tunnel

    Science.gov (United States)

    Meecham, W. C.; Hurdle, P. M.

    1974-01-01

    A 3.8 cm. model jet was operated in a wind tunnel with cross-flow in order to determine the effect on jet noise radiated characteristics. A method was developed for the determination of noise radiating characteristics of sources within reverberant wind tunnels; cross-correlation measurements were used. The averaging time in the cross-correlation is determined by the amount of background noise within the wind tunnel. It was found that cross-flow increases the radiated noise by 10 db. There was some indication of downstream radiation exceeding the sideline radiation.

  5. Recording stereoscopic 3D neurosurgery with a head-mounted 3D camera system.

    Science.gov (United States)

    Lee, Brian; Chen, Brian R; Chen, Beverly B; Lu, James Y; Giannotta, Steven L

    2015-06-01

    Stereoscopic three-dimensional (3D) imaging can present more information to the viewer and further enhance the learning experience over traditional two-dimensional (2D) video. Most 3D surgical videos are recorded from the operating microscope and only feature the crux, or the most important part of the surgery, leaving out other crucial parts of surgery including the opening, approach, and closing of the surgical site. In addition, many other surgeries including complex spine, trauma, and intensive care unit procedures are also rarely recorded. We describe and share our experience with a commercially available head-mounted stereoscopic 3D camera system to obtain stereoscopic 3D recordings of these seldom recorded aspects of neurosurgery. The strengths and limitations of using the GoPro(®) 3D system as a head-mounted stereoscopic 3D camera system in the operating room are reviewed in detail. Over the past several years, we have recorded in stereoscopic 3D over 50 cranial and spinal surgeries and created a library for education purposes. We have found the head-mounted stereoscopic 3D camera system to be a valuable asset to supplement 3D footage from a 3D microscope. We expect that these comprehensive 3D surgical videos will become an important facet of resident education and ultimately lead to improved patient care.

  6. RAG-3D: a search tool for RNA 3D substructures.

    Science.gov (United States)

    Zahran, Mai; Sevim Bayrak, Cigdem; Elmetwaly, Shereef; Schlick, Tamar

    2015-10-30

    To address many challenges in RNA structure/function prediction, the characterization of RNA's modular architectural units is required. Using the RNA-As-Graphs (RAG) database, we have previously explored the existence of secondary structure (2D) submotifs within larger RNA structures. Here we present RAG-3D-a dataset of RNA tertiary (3D) structures and substructures plus a web-based search tool-designed to exploit graph representations of RNAs for the goal of searching for similar 3D structural fragments. The objects in RAG-3D consist of 3D structures translated into 3D graphs, cataloged based on the connectivity between their secondary structure elements. Each graph is additionally described in terms of its subgraph building blocks. The RAG-3D search tool then compares a query RNA 3D structure to those in the database to obtain structurally similar structures and substructures. This comparison reveals conserved 3D RNA features and thus may suggest functional connections. Though RNA search programs based on similarity in sequence, 2D, and/or 3D structural elements are available, our graph-based search tool may be advantageous for illuminating similarities that are not obvious; using motifs rather than sequence space also reduces search times considerably. Ultimately, such substructuring could be useful for RNA 3D structure prediction, structure/function inference and inverse folding. PMID:26304547

  7. 3D-mallien muokkaus 3D-tulostamista varten CAD-ohjelmilla

    OpenAIRE

    Lehtimäki, Jarmo

    2013-01-01

    Insinöörityössäni käsitellään 3D-mallien tulostamista ja erityisesti 3D-mallien mallintamista niin, että kappaleiden valmistaminen 3D-tulostimella onnistuisi mahdollisimman hyvin. Työ tehtiin Prohoc Oy:lle, joka sijaitsee Vaasassa. 3D-tulostuspalveluun tuli jatkuvasti 3D-malleja, joiden tulostuksessa oli ongelmia. Työssäni tutkin näiden ongelmien syntyä ja tein ohjeita eri 3D-mallinnusohjelmille, joiden tarkoituksena on auttaa tekemään helpommin tulostettavia 3D-malleja. Työhön kuului myös et...

  8. Thin slice three dimentional (3D reconstruction versus CT 3D reconstruction of human breast cancer

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2013-01-01

    Full Text Available Background & objectives: With improvement in the early diagnosis of breast cancer, breast conserving therapy (BCT is being increasingly used. Precise preoperative evaluation of the incision margin is, therefore, very important. Utilizing three dimentional (3D images in a preoperative evaluation for breast conserving surgery has considerable significance, but the currently 3D CT scan reconstruction commonly used has problems in accurately displaying breast cancer. Thin slice 3D reconstruction is also widely used now to delineate organs and tissues of breast cancers. This study was aimed to compare 3D CT with thin slice 3D reconstruction in breast cancer patients to find a better technique for accurate evaluation of breast cancer. Methods: A total of 16-slice spiral CT scans and 3D reconstructions were performed on 15 breast cancer patients. All patients had been treated with modified radical mastectomy; 2D and 3D images of breast and tumours were obtained. The specimens were fixed and sliced at 2 mm thickness to obtain serial thin slice images, and reconstructed using 3D DOCTOR software to gain 3D images. Results: Compared with 2D CT images, thin slice images showed more clearly the morphological characteristics of tumour, breast tissues and the margins of different tissues in each slice. After 3D reconstruction, the tumour shapes obtained by the two reconstruction methods were basically the same, but the thin slice 3D reconstruction showed the tumour margins more clearly. Interpretation & conclusions: Compared with 3D CT reconstruction, thin slice 3D reconstruction of breast tumour gave clearer images, which could provide guidance for the observation and application of CT 3D reconstructed images and contribute to the accurate evaluation of tumours using CT imaging technology.

  9. 3D-PRINTING OF BUILD OBJECTS

    Directory of Open Access Journals (Sweden)

    SAVYTSKYI M. V.

    2016-03-01

    Full Text Available Raising of problem. Today, in all spheres of our life we can constate the permanent search for new, modern methods and technologies that meet the principles of sustainable development. New approaches need to be, on the one hand more effective in terms of conservation of exhaustible resources of our planet, have minimal impact on the environment and on the other hand to ensure a higher quality of the final product. Construction is not exception. One of the new promising technology is the technology of 3D -printing of individual structures and buildings in general. 3Dprinting - is the process of real object recreating on the model of 3D. Unlike conventional printer which prints information on a sheet of paper, 3D-printer allows you to display three-dimensional information, i.e. creates certain physical objects. Currently, 3D-printer finds its application in many areas of production: machine building elements, a variety of layouts, interior elements, various items. But due to the fact that this technology is fairly new, it requires the creation of detailed and accurate technologies, efficient equipment and materials, and development of common vocabulary and regulatory framework in this field. Research Aim. The analysis of existing methods of creating physical objects using 3D-printing and the improvement of technology and equipment for the printing of buildings and structures. Conclusion. 3D-printers building is a new generation of equipment for the construction of buildings, structures, and structural elements. A variety of building printing technics opens up wide range of opportunities in the construction industry. At this stage, printers design allows to create low-rise buildings of different configurations with different mortars. The scientific novelty of this work is to develop proposals to improve the thermal insulation properties of constructed 3D-printing objects and technological equipment. The list of key terms and notions of construction

  10. Cross-correlation matrix analysis of Chinese and American bank stocks in subprime crisis

    Science.gov (United States)

    Zhu, Shi-Zhao; Li, Xin-Li; Nie, Sen; Zhang, Wen-Qing; Yu, Gao-Feng; Han, Xiao-Pu; Wang, Bing-Hong

    2015-05-01

    In order to study the universality of the interactions among different markets, we analyze the cross-correlation matrix of the price of the Chinese and American bank stocks. We then find that the stock prices of the emerging market are more correlated than that of the developed market. Considering that the values of the components for the eigenvector may be positive or negative, we analyze the differences between two markets in combination with the endogenous and exogenous events which influence the financial markets. We find that the sparse pattern of components of eigenvectors out of the threshold value has no change in American bank stocks before and after the subprime crisis. However, it changes from sparse to dense for Chinese bank stocks. By using the threshold value to exclude the external factors, we simulate the interactions in financial markets. Project supported by the National Natural Science Foundation of China (Grant Nos. 11275186, 91024026, and FOM2014OF001) and the University of Shanghai for Science and Technology (USST) of Humanities and Social Sciences, China (Grant Nos. USST13XSZ05 and 11YJA790231).

  11. Two-dimensional structure from random multiparticle X-ray scattering images using cross-correlations

    Science.gov (United States)

    Pedrini, B.; Menzel, A.; Guizar-Sicairos, M.; Guzenko, V. A.; Gorelick, S.; David, C.; Patterson, B. D.; Abela, R.

    2013-04-01

    Knowledge of the structure of biological macromolecules, especially in their native environment, is crucial because of the close structure-function relationship. X-ray small-angle scattering is used to determine the shape of particles in solution, but the achievable resolution is limited owing to averaging over particle orientations. In 1977, Kam proposed to obtain additional structural information from the cross-correlation of the scattering intensities. Here we develop the method in two dimensions, and give a procedure by which the single-particle diffraction pattern is extracted in a model-independent way from the correlations. We demonstrate its application to a large set of synchrotron X-ray scattering images on ensembles of identical, randomly oriented particles of 350 or 200 nm in size. The obtained 15 nm resolution in the reconstructed shape is independent of the number of scatterers. The results are discussed in view of proposed ‘snapshot’ scattering by molecules in the liquid phase at X-ray free-electron lasers.

  12. Photoplethysmogram signal quality estimation using repeated Gaussian filters and cross-correlation

    International Nuclear Information System (INIS)

    Pulse oximeters are monitors that noninvasively measure heart rate and blood oxygen saturation (SpO2). Unfortunately, pulse oximetry is prone to artifacts which negatively impact the accuracy of the measurement and can cause a significant number of false alarms. We have developed an algorithm to segment pulse oximetry signals into pulses and estimate the signal quality in real time. The algorithm iteratively calculates a signal quality index (SQI) ranging from 0 to 100. In the presence of artifacts and irregular signal morphology, the algorithm outputs a low SQI number. The pulse segmentation algorithm uses the derivative of the signal to find pulse slopes and an adaptive set of repeated Gaussian filters to select the correct slopes. Cross-correlation of consecutive pulse segments is used to estimate signal quality. Experimental results using two different benchmark data sets showed a good pulse detection rate with a sensitivity of 96.21% and a positive predictive value of 99.22%, which was equivalent to the available reference algorithm. The novel SQI algorithm was effective and produced significantly lower SQI values in the presence of artifacts compared to SQI values during clean signals. The SQI algorithm may help to guide untrained pulse oximeter users and also help in the design of advanced algorithms for generating smart alarms. (paper)

  13. Heat shock-induced interactions among nuclear HSFs detected by fluorescence cross-correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pack, Chan-Gi, E-mail: changipack@amc.seoul.kr [Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul 138-736 (Korea, Republic of); Ahn, Sang-Gun [Dept. of Pathology, College of Dentistry, Chosun University, Seosuk-dong, Dong-gu, Gwangju 501-759 (Korea, Republic of)

    2015-07-31

    The cellular response to stress is primarily controlled in cells via transcriptional activation by heat shock factor 1 (HSF1). HSF1 is well-known to form homotrimers for activation upon heat shock and subsequently bind to target DNAs, such as heat-shock elements, by forming stress granules. A previous study demonstrated that nuclear HSF1 and HSF2 molecules in live cells interacted with target DNAs on the stress granules. However, the process underlying the binding interactions of HSF family in cells upon heat shock remains unclear. This study demonstrate for the first time that the interaction kinetics among nuclear HSF1, HSF2, and HSF4 upon heat shock can be detected directly in live cells using dual color fluorescence cross-correlation spectroscopy (FCCS). FCCS analyses indicated that the binding between HSFs was dramatically changed by heat shock. Interestingly, the recovery kinetics of interaction between HSF1 molecules after heat shock could be represented by changes in the relative interaction amplitude and mobility. - Highlights: • The binding interactions among nuclear HSFs were successfully detected. • The binding kinetics between HSF1s during recovery was quantified. • HSF2 and HSF4 strongly formed hetero-complex, even before heat shock. • Nuclear HSF2 and HSF4 bound to HSF1 only after heat shock.

  14. A cross-correlation method to search for gravitational wave bursts with AURIGA and Virgo

    Energy Technology Data Exchange (ETDEWEB)

    Bignotto, M; Cerdonio, M; Conti, L; Drago, M; Liguori, N [Dipartimento di Fisica, Universita di Padova, Via Marzolo 8, 35131 Padova (Italy); Bonaldi, M; Falferi, P; Vinante, A [Istituto di Fotonica e Nanotecnologie, CNR-Fondazione Bruno Kessler, I-38050 Povo (Trento) (Italy); Camarda, M [Dipartimento di Ingegneria Informatica, Universita di Padova, Via G. Gradenigo 6a, 35131 Padova (Italy); Longo, S; Ortolan, A [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro, Padova (Italy); Mezzena, R; Mion, A; Prodi, G A; Re, V; Salemi, F; Vitale, S [INFN, Gruppo Collegato di Trento, Sezione di Padova, I-38050 Povo, Trento (Italy); Taffarello, L; Vedovato, G; Zendri, J P [INFN, Sezione di Padova, Via Marzolo 8, 35131 Padova (Italy)], E-mail: virginia.re@lnl.infn.it (and others)

    2008-06-07

    We present a method to search for transient gravitational waves using a network of detectors with different spectral and directional sensitivities: the interferometer Virgo and the bar detector AURIGA. The data analysis method is based on the measurements of the correlated energy in the network by means of a weighted cross-correlation. To limit the computational load, this coherent analysis step is performed around time-frequency coincident triggers selected by an excess power event trigger generator tuned at low thresholds. The final selection of gravitational wave candidates is performed by a combined cut on the correlated energy and on the significance as measured by the event trigger generator. The method has been tested on one day of data of AURIGA and Virgo during September 2005. The outcomes are compared to the results of a stand-alone time-frequency coincidence search. We discuss the advantages and the limits of this approach, in view of a possible future joint search between AURIGA and one interferometric detector.

  15. Improving the galaxy clustering Fisher matrix: window function, bin cross-correlation, and bin redshift uncertainty

    CERN Document Server

    Bailoni, Alberto; Amendola, Luca

    2016-01-01

    The Fisher matrix is a widely used tool to forecast the performance of future experiments and approximate the likelihood of large data sets. Most of the forecasts for cosmological parameters in galaxy clustering studies rely on the Fisher matrix approach for large-scale experiments like DES, Euclid, or SKA. Here we improve upon the standard method by taking into account three effects: the finite window function, the correlation between redshift bins, and the uncertainty on the bin redshift. The first two effects are negligible only in the limit of infinite surveys. The third effect, on the contrary, is negligible for infinitely small bins. Here we show how to take into account these effects and what the impact on forecasts of a Euclid-type experiment will be. The main result of this article is that the windowing and the bin cross-correlation induce a considerable change in the forecasted errors, of the order of 10-30% for most cosmological parameters, while the redshift bin uncertainty can be neglected for bi...

  16. Environmental Quenching and Galactic Conformity in the Galaxy Cross-Correlation Signal

    CERN Document Server

    Hatfield, P W

    2016-01-01

    It has long been known that environment has a large effect on star formation in galaxies. There are several known plausible mechanisms to remove the cool gas needed for star formation, such as strangulation, harassment and ram-pressure stripping. It is unclear which process is dominant, and over what range of stellar mass. In this paper, we find evidence for suppression of the cross-correlation function between massive galaxies and less massive star-forming galaxies, giving a measure of how less likely a galaxy is to be star-forming in the vicinity of a more massive galaxy. We develop a formalism for modelling environmental quenching mechanisms within the Halo Occupation Distribution formalism. We find that at $z \\sim 2$ environment is not a significant factor in determining quenching of star-forming galaxies, and that galaxies are quenched with similar probabilities in group environments as they are globally. However, by $z \\sim 0.5$ galaxies are much less likely to be star forming when in a group environmen...

  17. Tomographic Imaging of Jakarta Area from Cross-correlation of Seismic Ambient Noise

    Science.gov (United States)

    Pranata, B.; Saygin, E.; Cummins, P. R.; Widiyantoro, S.; Nugraha, A. D.; Harjadi, P.; Suhardjono, S.

    2012-12-01

    Seismic imaging of sediment thickness of Jakarta is crucial where Jakarta city is currently being rapidly developed with major installations and high-rise structures being constructed at a fast pace. Therefore, information of surface geology and surface sediment thickness for Jakarta city is urgently required in order to mitigate the effects of earthquake hazards in the future. Because of this need, we deployed 36 broadband and shortperiod stations across Jakarta to record seismic ambient noise. We apply cross-correlation method to the simultaneously recorded data to retrieve interstation Green's functions. We measure group velocity dispersion of the retrieved Green's functions by applying narrowband filters. Dispersion measurements are then inverted with a nonlinear tomographic technique to image the shallow structure of Jakarta and its surrounding regions. Preliminary results from tomographic maps show low velocities dominantly located in central, west and north Jakarta. While the highest rate obtained is between stations in South Jakarta. This conforms with the known geological conditions in which the structure of sedimentary cover in northern Jakarta is thicker than the southern part.

  18. Measuring Time-of-Flight in an Ultrasonic LPS System Using Generalized Cross-Correlation

    Directory of Open Access Journals (Sweden)

    Carlos De Marziani

    2011-10-01

    Full Text Available In this article, a time-of-flight detection technique in the frequency domain is described for an ultrasonic Local Positioning System (LPS based on encoded beacons. Beacon transmissions have been synchronized and become simultaneous by means of the DS-CDMA (Direct-Sequence Code Division Multiple Access technique. Every beacon has been associated to a 255-bit Kasami code. The detection of signal arrival instant at the receiver, from which the distance to each beacon can be obtained, is based on the application of the Generalized Cross-Correlation (GCC, by using the cross-spectral density between the received signal and the sequence to be detected. Prior filtering to enhance the frequency components around the carrier frequency (40 kHz has improved estimations when obtaining the correlation function maximum, which implies an improvement in distance measurement precision. Positioning has been achieved by using hyperbolic trilateration, based on the Time Differences of Arrival (TDOA between a reference beacon and the others.

  19. SKA Weak Lensing I: Cosmological Forecasts and the Power of Radio-Optical Cross-Correlations

    Science.gov (United States)

    Harrison, Ian; Camera, Stefano; Zuntz, Joe; Brown, L.

    2016-09-01

    We construct forecasts for cosmological parameter constraints from weak gravitational lensing surveys involving the Square Kilometre Array (SKA). Considering matter content, dark energy and modified gravity parameters, we show that the first phase of the SKA (SKA1) can be competitive with other Stage III experiments such as the Dark Energy Survey (DES) and that the full SKA (SKA2) can potentially form tighter constraints than Stage IV optical weak lensing experiments, such as those that will be conducted with LSST, WFIRST-AFTA or Euclid-like facilities. Using weak lensing alone, going from SKA1 to SKA2 represents improvements by factors of ˜10 in matter, ˜10 in dark energy and ˜5 in modified gravity parameters. We also show, for the first time, the powerful result that comparably tight constraints (within ˜5%) for both Stage III and Stage IV experiments, can be gained from cross-correlating shear maps between the optical and radio wavebands, a process which can also eliminate a number of potential sources of systematic errors which can otherwise limit the utility of weak lensing cosmology.

  20. Environment degradation, economic growth and energy consumption nexus: A wavelet-windowed cross correlation approach

    Science.gov (United States)

    Jammazi, Rania; Aloui, Chaker

    2015-10-01

    This paper analyzes the interactive linkages between carbon dioxide (CO2) emissions, energy consumption (EC) and economic growth (EG) using a novel approach namely wavelet windowed cross correlation (WWCC) for six oil-exporting countries from the GCC (Gulf Cooperation Council) region over the period 1980-2012. Our empirical results show that there exists a bidirectional causal relationship between EC and EG. However, the results support the occurrence of unidirectional causality from EC to CO2 emissions without any feedback effects, and there exists a bidirectional causal relationship between EG and CO2 emissions for the region as a whole. The study suggests that environmental and energy policies should recognize the differences in the nexus between EC and EG in order to maintain sustainable EG in the GCC region. Our findings will be useful for GCC countries to better evaluate its situation in the future climate negotiations. The overall findings will help GCC countries assess its position better in future climate change negotiations.