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Sample records for joint time-frequency domain

  1. Analysis in the joint time-frequency domain of the identifying signatures of submerged targets insonified by dolphin clicks

    NASA Astrophysics Data System (ADS)

    Strifors, Hans C.; Gaunaurd, Guillermo C.; Moore, Patrick W.

    1997-06-01

    We study the scattering interaction of dolphin-emitted acoustic pulses ('clicks') with various elastic shells located, underwater, in front of the animal in a large test site in Kaneohe Bay, Hawaii. A carefully instrumented analog- to-digital system continuously captured the emitted clicks and also the returned, backscattered echoes. Using standard conditioning techniques and food reinforcers, the dolphin is taught to push an underwater paddle when the 'correct' target -- the one he has been trained to identify -- is presented to him. He communicates to us his consistently correct identifying choices in this manner. By means of several time- frequency distributions (TFD) of the Wigner-type, or Cohen class, we examine echoes returned by three types of cylindrical shells. The time-frequency distributions we compare in this survey are the pseudo-Wigner distribution (PWD), the Choi-Williams distribution (CWD), the adaptive spectrogram (AS), the cone-shaped distribution (CSD), the Gabor spectrogram (GS), and the spectrogram (SPEC). To be satisfactory for target identification purposes, a time- frequency representation of the echoes should display a sufficient amount of distinguishing features, and still be robust enough to suppress the interference of noise contained in the received signals. Both these properties in a time- frequency distribution depend on the distribution's capability of concentrating the featuers in time and frequency and of handling cross-term interference. With some time-frequency distributions there is a trade-off between the concentration of features and the suppression of cross-term interference. The results of our investigation serve the twofold purposes of (1) advancing the understanding of the amazing target identification capability of dolphins, and (2) to assist in assessing the possibility of identifying submerged targets using active sonar and a classifier based on target signatures in the combined time-frequency domain.

  2. Characterization of Cardio signals by time-frequency domain analysis

    E-print Network

    Sayan Mukherjee; Sanjay Kumar Palit; Santo Banerjee; MRK Ariffin; Lamberto Rondoni; Dilip Kumar Bhattacharya

    2015-08-18

    Long term behavior of nonlinear deterministic continuous time signals can be studied in terms of their reconstructed attractors. Reconstructed attractors of a continuous signal are meant to be topologically equivalent representations of the dynamics of the unknown dynamical system which generates the signal. Sometimes, geometry of the attractor or its complexity may give important information on the system of interest. However, if the trajectories of the attractor behave as if they are not coming from continuous system or there exists many spike like structures on the path of the system trajectories, then there is no way to characterize the shape of the attractor. In this article, the traditional attractor reconstruction method is first used for two types of ECG signals: Normal healthy persons (NHP) and Congestive Heart failure patients (CHFP). As common in such a framework, the reconstructed attractors are not at all well formed and hence it is not possible to adequately characterize their geometrical features. Thus, we incorporate frequency domain information to the given time signals. This is done by transforming the signals to a time frequency domain by means of suitable Wavelet transforms (WT). The transformed signal concerns two non homogeneous variables and is still quite difficult to use to reconstruct some dynamics out of it. By applying a suitable mapping, this signal is further converted into integer domain and a new type of 3D plot, called integer lag plot, which characterizes and distinguishes the ECG signals of NHP and CHFP, is finally obtained.

  3. Joint DOD/DOA estimation in MIMO radar exploiting time-frequency signal representations

    NASA Astrophysics Data System (ADS)

    Zhang, Yimin D.; Amin, Moeness G.; Himed, Braham

    2012-12-01

    In this article, we consider the joint estimation of direction-of-departure (DOD) and direction-of-arrival (DOA) information of maneuvering targets in a bistatic multiple-input multiple-output (MIMO) radar system that exploits spatial time-frequency distribution (STFD). STFD has been found useful in solving various array processing problems, such as direction finding and blind source separation, where nonstationary signals with time-varying spectral characteristics are encountered. The STFD approach to array processing has been primarily limited to conventional problems for passive radar platform that deals with signal arrivals, while its use in a MIMO radar configuration has received much less attention. This paper examines the use of STFD in MIMO radar systems with application to direction finding of moving targets with nonstationary signatures. Within this framework, we consider the use of joint transmit and receive apertures for the improved estimation of both target time-varying Doppler signatures and joint DOD/DOA. It is demonstrated that the STFD is an effective tool in MIMO radar processing when moving targets produce Doppler signatures that are highly localized in the time-frequency domain.

  4. EEG biometric identification: a thorough exploration of the time-frequency domain

    E-print Network

    Weidemann, Christoph

    EEG biometric identification: a thorough exploration of the time-frequency domain Marcos Del of future biometric systems. S Online supplementary data available from stacks.iop.org/jne/12/056019/mmedia

  5. Comparison of pulse and SFCW GPR in time, frequency and wavelet domain

    NASA Astrophysics Data System (ADS)

    De Pue, Jan; Van De Vijver, Ellen; Cornelis, Wim; Van Meirvenne, Marc

    2014-05-01

    Ground penetrating radar (GPR) systems operating in the time- or frequency domain are two fundamentally different concepts, pursuing the same objective: non-invasive characterization of the subsurface. The aim of this study is to compare the performance of these two GPR systems in the time, frequency and wavelet domain. The time domain GPR investigated is the Utilityscan DF. This is a ground coupled GPR with a digital dual-frequency antenna (300 and 800 MHz). The Geoscope GS3F and VX1213 antenna array from 3DRadar is the frequency domain GPR used in this comparison. It is an air coupled stepped frequency continuous wave (SFCW) GPR with a frequency bandwidth from 200 MHz to 3000 MHz. Using data from several test sites of various soil types, the data is evaluated in the time domain, the frequency domain and the wavelet domain. Each of these domains contains specific information regarding the data quality. Presenting the data in the time domain, allows visualizing the subsurface reflections. This makes it visible how strong the data is affected by internal interference, ringing and other noise. To compensate for the attenuation of the signal in time, automatic gain control is applied. The maximum of this gain function indicates the time where the signal is attenuated completely and noise becomes more dominant, corresponding with the maximal penetration depth of the different GPR systems. In the frequency domain, the data allows to investigate which frequencies contain most valuable information and which ones are affected by noise. Finally, by performing a wavelet transformation the data is transformed to the time-frequency domain. Due to frequency dependent attenuation of electromagnetic signals in the soil, low frequencies will be more dominant in deeper layers, and high frequencies will not be present anymore. This is determining for the range resolution of the data throughout the traveltime of the signal. This work is a contribution to COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar".

  6. Initialization method for speech separation algorithms that work in the time-frequency domain.

    PubMed

    Sarmiento, Auxiliadora; Durán-Díaz, Iván; Cruces, Sergio

    2010-04-01

    This article addresses the problem of the unsupervised separation of speech signals in realistic scenarios. An initialization procedure is proposed for independent component analysis (ICA) algorithms that work in the time-frequency domain and require the prewhitening of the observations. It is shown that the proposed method drastically reduces the permuted solutions in that domain and helps to reduce the execution time of the algorithms. Simulations confirm these advantages for several ICA instantaneous algorithms and the effectiveness of the proposed technique in emulated reverberant environments. PMID:20369978

  7. Distinction between harmonic and structural components in ambient excitation tests using the time-frequency domain decomposition technique

    NASA Astrophysics Data System (ADS)

    Le, Thien-Phu; Argoul, Pierre

    2015-02-01

    The time-frequency domain decomposition technique has been proposed for modal identification in ambient vibration testing. In the presence of harmonic excitations, the modal identification process can provide not only structural modes but also non-structural ones relative to harmonic components. It is thus important to distinguish between them. In this study, by using the time-frequency domain decomposition technique, it is demonstrated that the distinction between non-structural harmonic components and those of the structural responses can be possible, and it is merged into the general procedure of the time-frequency domain decomposition method. This proposition is then verified by numerical examples and by a laboratory test.

  8. A statistical comparison of EEG time- and time-frequency domain representations of error processing.

    PubMed

    Munneke, Gert-Jan; Nap, Tanja S; Schippers, Eveline E; Cohen, Michael X

    2015-08-27

    Successful behavior relies on error detection and subsequent remedial adjustment of behavior. Researchers have identified two electrophysiological signatures of error processing: the time-domain error-related negativity (ERN), and the time-frequency domain increased power in the delta/theta frequency bands (~2-8 Hz). The relationship between these two signatures is not entirely clear: on the one hand they occur after the same type of event and with similar latency, but on the other hand, the time-domain ERP component contains only phase-locked activity whereas the time-frequency response additionally contains non-phase-locked dynamics. Here we examined the ERN and error-related delta/theta activity in relation to each other, focusing on within-subject analyses that utilize single-trial data. Using logistic regression, we constructed three statistical models in which the accuracy of each trial was predicted from the ERN, delta/theta power, or both. We found that both the ERN and delta/theta power worked roughly equally well as predictors of single-trial accuracy (~70% accurate prediction). Furthermore, a model including both measures provided a stronger overall prediction compared to either model alone. Based on these findings two conclusions are drawn: first, the phase-locked part of the EEG signal appears to be roughly as predictive of single-trial response accuracy as the non-phase-locked part; second, the single-trial ERP and delta/theta power contain both overlapping and independent information. PMID:26032741

  9. EEG biometric identification: a thorough exploration of the time-frequency domain

    NASA Astrophysics Data System (ADS)

    DelPozo-Banos, Marcos; Travieso, Carlos M.; Weidemann, Christoph T.; Alonso, Jesús B.

    2015-10-01

    Objective. Although interest in using electroencephalogram (EEG) activity for subject identification has grown in recent years, the state of the art still lacks a comprehensive exploration of the discriminant information within it. This work aims to fill this gap, and in particular, it focuses on the time-frequency representation of the EEG. Approach. We executed qualitative and quantitative analyses of six publicly available data sets following a sequential experimentation approach. This approach was divided in three blocks analysing the configuration of the power spectrum density, the representation of the data and the properties of the discriminant information. A total of ten experiments were applied. Main results. Results show that EEG information below 40 Hz is unique enough to discriminate across subjects (a maximum of 100 subjects were evaluated here), regardless of the recorded cognitive task or the sensor location. Moreover, the discriminative power of rhythms follows a W-like shape between 1 and 40 Hz, with the central peak located at the posterior rhythm (around 10 Hz). This information is maximized with segments of around 2 s, and it proved to be moderately constant across montages and time. Significance. Therefore, we characterize how EEG activity differs across individuals and detail the optimal conditions to detect subject-specific information. This work helps to clarify the results of previous studies and to solve some unanswered questions. Ultimately, it will serve as guide for the design of future biometric systems.

  10. Deriving Lifetime Maps in the Time/Frequency Domain of Coherent Structures in the Turbulent Boundary Layer

    NASA Technical Reports Server (NTRS)

    Palumbo, Dan

    2008-01-01

    The lifetimes of coherent structures are derived from data correlated over a 3 sensor array sampling streamwise sidewall pressure at high Reynolds number (> 10(exp 8)). The data were acquired at subsonic, transonic and supersonic speeds aboard a Tupolev Tu-144. The lifetimes are computed from a variant of the correlation length termed the lifelength. Characteristic lifelengths are estimated by fitting a Gaussian distribution to the sensors cross spectra and are shown to compare favorably with Efimtsov s prediction of correlation space scales. Lifelength distributions are computed in the time/frequency domain using an interval correlation technique on the continuous wavelet transform of the original time data. The median values of the lifelength distributions are found to be very close to the frequency averaged result. The interval correlation technique is shown to allow the retrieval and inspection of the original time data of each event in the lifelength distributions, thus providing a means to locate and study the nature of the coherent structure in the turbulent boundary layer. The lifelength data are converted to lifetimes using the convection velocity. The lifetime of events in the time/frequency domain are displayed in Lifetime Maps. The primary purpose of the paper is to validate these new analysis techniques so that they can be used with confidence to further characterize the behavior of coherent structures in the turbulent boundary layer.

  11. Joint discrepancy evaluation of an existing steel bridge using time-frequency and wavelet-based approach

    NASA Astrophysics Data System (ADS)

    Walia, Suresh Kumar; Patel, Raj Kumar; Vinayak, Hemant Kumar; Parti, Raman

    2013-12-01

    The objective of this study is to bring out the errors introduced during construction which are overlooked during the physical verification of the bridge. Such errors can be pointed out if the symmetry of the structure is challenged. This paper thus presents the study of downstream and upstream truss of newly constructed steel bridge using time-frequency and wavelet-based approach. The variation in the behavior of truss joints of bridge with variation in the vehicle speed has been worked out to determine their flexibility. The testing on the steel bridge was carried out with the same instrument setup on both the upstream and downstream trusses of the bridge at two different speeds with the same moving vehicle. The nodal flexibility investigation is carried out using power spectral density, short-time Fourier transform, and wavelet packet transform with respect to both the trusses and speed. The results obtained have shown that the joints of both upstream and downstream trusses of the bridge behave in a different manner even if designed for the same loading due to constructional variations and vehicle movement, in spite of the fact that the analytical models present a simplistic model for analysis and design. The difficulty of modal parameter extraction of the particular bridge under study increased with the increase in speed due to decreased excitation time.

  12. Real-time frequency domain temperature and oxygen sensor with a single optical fiber.

    PubMed

    Liao, S C; Xu, Z; Izatt, J A; Alcala, J R

    1997-11-01

    The combined excited-state phosphorescence life-times of an alexandrite crystal and platinum tetraphenylporphyrin Pt(TPP) in a single-fiber sensor are used to monitor temperature and oxygen concentration in the physiological range from 15-45 degrees C and 0-50% O2 with precision of 0.24 degree C and 0.15% O2 and accuracy of 0.28 degree C and 0.2% O2. A 500-micron cubic alexandrite crystal bound to the distal end of a 750-micron-diameter optical fiber core and the Pt(TPP) coated circumferentially with a length of 1 cm from the end of the same fiber are excited with pulsed super-bright blue LED light. This apparatus uses a 125-kHz sampler for data acquisition and frequency domain methods for signal processing. The instrument amplifies both the dc and ac components of the photomultiplier output and band limits the signal to 20 kHz. The fundamental frequency of the excitation is set to 488.3 Hz and the highest harmonic used is the 35th. This bandlimited signal is sampled and averaged over a few hundred cycles in the time domain. The frequency domain representation of the data is obtained by employing fast Fourier transform algorithms. The phase delay and the modulation ratio of each sampled harmonic are then computed. At least four log-spaced harmonic phases or modulations are averaged before decoding the two lifetimes of temperature and oxygen phosphorescent sensors. A component of zero lifetime is introduced to account for the excitation backscatter leakage through optical interference filters seen by the photodetector. Linear and second-order empirical polynomials are employed to compute the temperatures and oxygen concentrations from the inverse lifetimes. In the situation of constant oxygen concentration, the lifetime of Pt(TPP) changes with temperature but can be compensated using the measured temperature lifetime. The system drift is 0.24 degree C for the temperature measurement and 0.59% for the oxygen concentration measurement over 30 h of continuous operation. The instrumentation and methods allow for 6-s update times and 90-s full-response times. PMID:9353991

  13. Time-frequency domain analysis of vibration signals for machinery diagnostics. 3: The present power spectral density

    NASA Astrophysics Data System (ADS)

    Wang, W. J.; McFadden, P. D.

    1992-07-01

    The Present Power Spectral Density (PPSD), also referred to as the local power spectral density, is defined and its application to the calculation of the time frequency distribution of a nonstationary signal is examined. The PPSD distribution represents the energy distribution of the signal over the frequency domain at every instant of time. It can correctly reveal the presence of local changes in the signal, and avoids the disadvantages arising from the nonlinearity which is inherent in the Wigner-Ville distribution. The selection of the local emphasizing function is discussed, and it is shown that the Gaussian function is well suited to the calculation of the PPSD, giving a distribution which is free from ripple and easy to interpret. The application of the PPSD is demonstrated using numerically generated test signals and experimentally measured time domain averages of the gear meshing vibration from industrial and helicopter gearboxes. The results show that the PPSD provides a powerful tool for the early detection of local gear damage.

  14. Comparison of air-launched and ground-coupled configurations of SFCW GPR in time, frequency and wavelet domain

    NASA Astrophysics Data System (ADS)

    Van De Vijver, Ellen; De Pue, Jan; Cornelis, Wim; Van Meirvenne, Marc

    2015-04-01

    A stepped frequency continuous wave (SFCW) ground penetrating radar (GPR) system produces waveforms consisting of a sequence of sine waves with linearly increasing frequency. By adopting a wide frequency bandwidth, SFCW GPR systems offer an optimal resolution at each achievable measurement depth. Furthermore, these systems anticipate an improved penetration depth and signal-to-noise ratio (SNR) as compared to time-domain impulse GPRs, because energy is focused in one single frequency at a time and the phase and amplitude of the reflected signal is recorded for each discrete frequency step. However, the search for the optimal practical implementation of SFCW GPR technology to fulfil these theoretical advantages is still ongoing. In this study we compare the performance of a SFCW GPR system for air-launched and ground-coupled antenna configurations. The first is represented by a 3d-Radar Geoscope GS3F system operated with a V1213 antenna array. This array contains 7 transmitting and 7 receiving antennae resulting in 13 measurement channels at a spacing of 0.075 m and providing a total scan width of 0.975 m. The ground-coupled configuration is represented by 3d-Radar's latest-generation SFCW system, GeoScope Mk IV, operated with a DXG1212 antenna array. With 6 transmitting and 5 receiving antennae this array provides 12 measurement channels and an effective scan width of 0.9 m. Both systems were tested on several sites representative of various application environments, including a test site with different road specimens (Belgian Road Research Centre) and two test areas in different agricultural fields in Flanders, Belgium. For each test, data acquisition was performed using the full available frequency bandwidth of the systems (50 to 3000 MHz). Other acquisition parameters such as the frequency step and dwell time were varied in different tests. Analyzing the data of the different tests in time, frequency and wavelet domain allows to evaluate different performance aspects of the air-launched and ground-coupled configurations such as acquisition speed, measurement resolution, SNR and penetration depth. Based on this analysis, we highlight the advantages and disadvantages of the different SFCW GPR configurations in different application environments. The authors thank Colette Grégoire and Carl Van Geem of the Belgian Road Research Centre for the collaboration on the road test site. This work is a contribution to COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar".

  15. J. of Electromagn. Waves and Appl., Vol. 25, 10691080, 2011 JOINT TIME-FREQUENCY ANALYSIS OF RADAR

    E-print Network

    Myung, Noh-Hoon

    MICRO-DOPPLER SIGNATURES FROM AIRCRAFT ENGINE MODELS H. Lim and J. H. Park Department of Electrical--Micro-Doppler signatures from four CAD aircraft engine models and one experimental engine model are analyzed using joint]. However, the application of JTFA to aircraft engine models has not been reported so far, although it can

  16. Measuring Multi-Joint Stiffness during Single Movements: Numerical Validation of a Novel Time-Frequency Approach

    PubMed Central

    Piovesan, Davide; Pierobon, Alberto; DiZio, Paul; Lackner, James R.

    2012-01-01

    This study presents and validates a Time-Frequency technique for measuring 2-dimensional multijoint arm stiffness throughout a single planar movement as well as during static posture. It is proposed as an alternative to current regressive methods which require numerous repetitions to obtain average stiffness on a small segment of the hand trajectory. The method is based on the analysis of the reassigned spectrogram of the arm's response to impulsive perturbations and can estimate arm stiffness on a trial-by-trial basis. Analytic and empirical methods are first derived and tested through modal analysis on synthetic data. The technique's accuracy and robustness are assessed by modeling the estimation of stiffness time profiles changing at different rates and affected by different noise levels. Our method obtains results comparable with two well-known regressive techniques. We also test how the technique can identify the viscoelastic component of non-linear and higher than second order systems with a non-parametrical approach. The technique proposed here is very impervious to noise and can be used easily for both postural and movement tasks. Estimations of stiffness profiles are possible with only one perturbation, making our method a useful tool for estimating limb stiffness during motor learning and adaptation tasks, and for understanding the modulation of stiffness in individuals with neurodegenerative diseases. PMID:22448233

  17. High Order Statistics and Time-Frequency Domain to Classify Heart Sounds for Subjects under Cardiac Stress Test

    PubMed Central

    Moukadem, Ali; Schmidt, Samuel; Dieterlen, Alain

    2015-01-01

    This paper considers the problem of classification of the first and the second heart sounds (S1 and S2) under cardiac stress test. The main objective is to classify these sounds without electrocardiogram (ECG) reference and without taking into consideration the systolic and the diastolic time intervals criterion which can become problematic and useless in several real life settings as severe tachycardia and tachyarrhythmia or in the case of subjects being under cardiac stress activity. First, the heart sounds are segmented by using a modified time-frequency based envelope. Then, to distinguish between the first and the second heart sounds, new features, named ?opt, ?, and ?, based on high order statistics and energy concentration measures of the Stockwell transform (S-transform) are proposed in this study. A study of the variation of the high frequency content of S1 and S2 over the HR (heart rate) is also discussed. The proposed features are validated on a database that contains 2636 S1 and S2 sounds corresponding to 62 heart signals and 8 subjects under cardiac stress test collected from healthy subjects. Results and comparisons with existing methods in the literature show a large superiority for our proposed features. PMID:26089957

  18. Precambrian basement control on joint domains in northwestern Ohio

    SciTech Connect

    Dean, S.L.; Armstrong, W.B.; Kulander, B.R.

    1986-08-01

    Joint attitudes in Upper Silurian and Lower Devonian carbonates in northwestern Ohio reveal a marked north-south-trending joint domain boundary in Lucas and Wood Counties. East of the domain boundary, first-formed systematic joints trend N45/sup 0/W; west of this boundary, first-formed systematics trend N40/sup 0/E. The line of change in joint trends follows the Lucas County monocline-Bowling Green fault complex and the projected position of the Grenville front from the Canadian shield. Basement well information and gravity and magnetic data indicate a major change in Precambrian rock types across the domain boundary that is coincident with the projected position of the Grenville front. Observed joint patterns are interpreted to result from extensional tectonics associated with the evolution of the Findlay arch and Michigan basin. Recurrent movements on the Bowling Green fault during the early and middle Paleozoic may have been caused by reactivation of Grenville-age faults, which ultimately localized the joint domain boundary along the Lucas County monocline-Bowling Green fault trend.

  19. Filtering in the joint time/chirp-rate domain for separation of quadratic and cubic phase chirp signals

    NASA Astrophysics Data System (ADS)

    Özgen, Mehmet Tankut

    2012-12-01

    This article investigates the possibility and convenience of a filtering operation in the joint time/chirp-rate (TCR) domain, and proposes a novel linear TCR filter for decomposing multicomponent signals into their quadratic and/or cubic phase chirp components with monotonic instantaneous chirp-rate (ICR) laws only. The TCR domain mask of the filter is selected on a display of a TCR representation of an input signal to isolate the desired chirp component. Projecting the input signal onto the phase signal associated with the TCR mask and approximating the phase difference in this projection operation in terms of ICR values result in the proposed TCR filter that recovers the selected component. Simulations illustrate the proposed filtering in recovery of undersampled cubic phase signals and in resolving back-to-back objects from in-line holograms for which cases it is easier to design filter masks in the TCR domain than in the time-frequency domain.

  20. Time-frequency filtering for classifying targets in nonstationary clutter

    NASA Astrophysics Data System (ADS)

    Gomatam, Vikram Thiruneermalai; Loughlin, Patrick

    2014-06-01

    Classifying underwater targets from their sonar backscatter is often complicated by induced or self-noise (i.e. clutter, reverberation) arising from the scattering of the sonar pulse from non-target objects. Because clutter is inherently nonstationary, and because the propagation environment can induce nonstationarities as well, in addition to any nonstationarities / time-varying spectral components of the target echo itself, a joint phase space approach to target classification has been explored. In this paper, we apply a previously developed minimum mean square time-frequency spectral estimation method to design a bank of time-frequency filters from training data to distinguish targets from clutter. The method is implemented in the ambiguity domain in order to reduce computational requirements. In this domain, the optimal filter (more commonly called a "kernel" in the time-frequency literature) multiples the ambiguity function of the received signal, and then the mean squared distance to each target class is computed. Simulations demonstrate that the class-specific optimal kernel better separates each target from the clutter and other targets, compared to a simple mean-squared distance measure with no kernel processing.

  1. JPEG image steganalysis using joint discrete cosine transform domain features

    NASA Astrophysics Data System (ADS)

    Xia, Zhihua; Sun, Xingming; Liang, Wei; Qin, Jiaohua; Li, Feng

    2010-04-01

    A JPEG image steganalysis scheme based on joint discrete cosine transform (DCT) domain features is proposed. Intrinsic characteristics of DCT coefficients, such as histogram, intrablock correlation, and interblock correlation, are exploited to construct three feature sets. Support vector machine is utilized to learn and discriminate the difference of features between cover and stego images. First, the three feature sets are investigated separately to reveal their individual capability of attacking steganographic methods. Second, the feature sets are combined to form a joint feature set with better performance. Experimental results demonstrate that all three feature sets individually succeed in attacking the four typical steganographic tools to some extent, with the intrablock feature set performing the best. Furthermore, the comparison experiments show that the jointed feature set not only outperforms the three individual feature sets but also proves to be better than a previous state-of-the-art steganalysis method.

  2. Spectroscopy by joint spectral and time domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Szkulmowski, Maciej; Tamborski, Szymon; Wojtkowski, Maciej

    2015-03-01

    We present the methodology for spectroscopic examination of absorbing media being the combination of Spectral Optical Coherence Tomography and Fourier Transform Spectroscopy. The method bases on the joint Spectral and Time OCT computational scheme and simplifies data analysis procedure as compared to the mostly used windowing-based Spectroscopic OCT methods. The proposed experimental setup is self-calibrating in terms of wavelength-pixel assignment. The performance of the method in measuring absorption spectrum was checked with the use of the reflecting phantom filled with the absorbing agent (indocyanine green). The results show quantitative accordance with the controlled exact results provided by the reference method.

  3. Demarcation of homogeneous structural domains within a rock mass based on joint orientation and trace length

    NASA Astrophysics Data System (ADS)

    Song, Shengyuan; Wang, Qing; Chen, Jianping; Cao, Chen; Li, Yanyan; Zhou, Xin

    2015-11-01

    This paper presents a new method for determining the structural domain boundaries within the rock mass. This new method is based on a statistical comparison of data from pairs of sample regions. The stereonet is divided into 100 windows with approximately equal areas. The poles of joints occurring in each corresponding window on the two projection plots of the regions being compared are then merged and arranged in ascending order with respect to their trace lengths. Finally, the Wald-Wolfowitz runs test is used to identify the homogeneity of structural populations by analyzing the joint sequence. Based on a significance level of 0.01, the homogeneity of structural populations collected from four adjacent adits at the Songta dam site is determined using the proposed method. The results show that the boundaries of structural domain change with the sizes of the sampling domains being compared. The initial sampling domains should be selected according to the engineering geological conditions of the studied area. In addition, the clear advantage of the proposed method is that both joint orientation and trace length are considered.

  4. Time-Frequency Resolved Four-Wave Mixing: From Control to Computing

    NASA Astrophysics Data System (ADS)

    Apkarian, V. A.

    2002-03-01

    Joint time-frequency domain measurements of coherent anti-Stokes Raman scattering constitutes a complete experiment in the preparation, manipulation and interrogation of molecular coherences - the three key ingredients of control in quantum chemistry or quantum computing. We show the direct mapping of this four-wave mixing process on the sufficient set of logical operations to execute universal quantum computing.(R. Zadoyan, D.Kohen, D. Lidar, V. A. Apkarian, Chem. Phys., 266, 323, (2001).) We then combine logic gates to demonstrate quantum algorithms with significant speed-up over classical solutions.(Z. Bihary, D. R. Glenn, D. A. Lidar, V. A. Apkarian, (PRL, submitted, 2001).) Scale-up through shaped pulses, and experimental limitations in this regard will be discussed, along experimental approaches for cascading logical operations. Quantum encryption and communication are potential practical applications of the existing method.

  5. Audio classification from time-frequency texture

    E-print Network

    Slotine, Jean-Jacques E.

    Time-frequency representations of audio signals often resemble texture images. This paper derives a simple audio classification algorithm based on treating sound spectrograms as texture images. The algorithm is inspired ...

  6. Joint synchronization and calibration of multi-channel transform-domain charge sampling receivers 

    E-print Network

    Kotte Prakasam, Pradeep

    2010-07-14

    OF SCIENCE May 2009 Major Subject: Electrical Engineering JOINT SYNCHRONIZATION AND CALIBRATION OF MULTI-CHANNEL TRANSFORM-DOMAIN CHARGE SAMPLING RECEIVERS A Thesis by PRADEEP KOTTE PRAKASAM Submitted to the O?ce of Graduate Studies of Texas A&M University... in partial fulflllment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Sebastian Hoyos Committee Members, Jose Silva-Martinez Henry Pflster Cesar O. Malave Head of Department, Costas Georghiades May 2009 Major Subject...

  7. Brain connectivity study of joint attention using frequency-domain optical imaging technique

    NASA Astrophysics Data System (ADS)

    Chaudhary, Ujwal; Zhu, Banghe; Godavarty, Anuradha

    2010-02-01

    Autism is a socio-communication brain development disorder. It is marked by degeneration in the ability to respond to joint attention skill task, from as early as 12 to 18 months of age. This trait is used to distinguish autistic from nonautistic populations. In this study, diffuse optical imaging is being used to study brain connectivity for the first time in response to joint attention experience in normal adults. The prefrontal region of the brain was non-invasively imaged using a frequency-domain based optical imager. The imaging studies were performed on 11 normal right-handed adults and optical measurements were acquired in response to joint-attention based video clips. While the intensity-based optical data provides information about the hemodynamic response of the underlying neural process, the time-dependent phase-based optical data has the potential to explicate the directional information on the activation of the brain. Thus brain connectivity studies are performed by computing covariance/correlations between spatial units using this frequency-domain based optical measurements. The preliminary results indicate that the extent of synchrony and directional variation in the pattern of activation varies in the left and right frontal cortex. The results have significant implication for research in neural pathways associated with autism that can be mapped using diffuse optical imaging tools in the future.

  8. Computer-aided classification of rheumatoid arthritis in finger joints using frequency domain optical tomography

    NASA Astrophysics Data System (ADS)

    Klose, C. D.; Kim, H. K.; Netz, U.; Blaschke, S.; Zwaka, P. A.; Mueller, G. A.; Beuthan, J.; Hielscher, A. H.

    2009-02-01

    Novel methods that can help in the diagnosis and monitoring of joint disease are essential for efficient use of novel arthritis therapies that are currently emerging. Building on previous studies that involved continuous wave imaging systems we present here first clinical data obtained with a new frequency-domain imaging system. Three-dimensional tomographic data sets of absorption and scattering coefficients were generated for 107 fingers. The data were analyzed using ANOVA, MANOVA, Discriminant Analysis DA, and a machine-learning algorithm that is based on self-organizing mapping (SOM) for clustering data in 2-dimensional parameter spaces. Overall we found that the SOM algorithm outperforms the more traditional analysis methods in terms of correctly classifying finger joints. Using SOM, healthy and affected joints can now be separated with a sensitivity of 0.97 and specificity of 0.91. Furthermore, preliminary results suggest that if a combination of multiple image properties is used, statistical significant differences can be found between RA-affected finger joints that show different clinical features (e.g. effusion, synovitis or erosion).

  9. Multipixel system for gigahertz frequency-domain optical imaging of finger joints

    NASA Astrophysics Data System (ADS)

    Netz, Uwe J.; Beuthan, Jürgen; Hielscher, Andreas H.

    2008-03-01

    Frequency-domain optical imaging systems have shown great promise for characterizing blood oxygenation, hemodynamics, and other physiological parameters in human and animal tissues. However, most of the frequency domain systems presented so far operate with source modulation frequencies below 150MHz. At these low frequencies, their ability to provide accurate data for small tissue geometries such as encountered in imaging of finger joints or rodents is limited. Here, we present a new system that can provide data up to 1GHz using an intensity modulated charged coupled device camera. After data processing, the images show the two-dimensional distribution of amplitude and phase of the light modulation on the finger surface. The system performance was investigated and test measurements on optical tissue phantoms were taken to investigate whether higher frequencies yield better signal-to-noise ratios (SNRs). It could be shown that local changes in optical tissue properties, as they appear in the initial stages of rheumatoid arthritis in a finger joint, are detectable by simple image evaluation, with the range of modulation frequency around 500MHz proving to yield the highest SNR.

  10. Time-frequency characterisation of paediatric heart sounds

    NASA Astrophysics Data System (ADS)

    Leung, Terence Sze-Tat

    1998-08-01

    The operation of the heart can be monitored by the sounds it emits. Structural defects or malfunction of the heart valves will cause additional abnormal sounds such as murmurs and ejection clicks. This thesis aims to characterise the heart sounds of three groups of children who either have an Atrial Septal Defect (ASD), a Ventricular Septal Defect (VSD), or are normal. Two aspects of heart sounds have been specifically investigated; the time-frequency analysis of systolic murmurs and the identification of splitting patterns in the second heart sound. The analysis is based on 42 paediatric heart sound recordings. Murmurs are sounds generated by turbulent flow of blood in the heart. They can be found in patients with both pathological and non-pathological conditions. The acoustic quality of the murmurs generated in each heart condition are different. The first aspect of this work is to characterise the three types of murmurs in the time- frequency domain. Modern time-frequency methods including, the Wigner-Ville Distribution, Smoothed Pseudo Wigner-Ville Distribution, Choi-Williams Distribution and spectrogram have been applied to characterise the murmurs. It was found that the three classes of murmurs exhibited different signatures in their time-frequency representations. By performing Discriminant Analysis, it was shown that spectral features extracted from the time- frequency representations can be used to distinguish between the three classes. The second aspect of the research is to identify splitting patterns in the second heart sound, which consists of two acoustic components due to the closure of the aortic valve and pulmonary valve. The aortic valve usually closes before the pulmonary valve, introducing a time delay known as 'split'. The split normally varies in duration over the respiratory cycle. In certain pathologies such as the ASD, the split becomes fixed over the respiration cycle. A technique based on adaptive signal decomposition is developed to measure the split and hence to identify the splitting pattern as either 'variable' or 'fixed'. This work has successfully characterised the murmurs and splitting patterns in the three groups of patients. Features extracted can be used for diagnostic purposes.

  11. High-resolution time-frequency distributions for fall detection

    NASA Astrophysics Data System (ADS)

    Amin, Moeness G.; Zhang, Yimin D.; Boashash, Boualem

    2015-05-01

    In this paper, we examine the role of high-resolution time-frequency distributions (TFDs) of radar micro-Doppler signatures for fall detection. The work supports the recent and rising interest in using emerging radar technology for elderly care and assisted living. Spectrograms have been the de facto joint-variable signal representation, depicting the signal power in both time and frequency. Although there have been major advances in designing quadratic TFDs which are superior to spectrograms in terms of detailing the local signal behavior, the contributions of these distributions in the area of human motion classifications and their offerings in enhanced feature extractions have not yet been properly evaluated. The main purpose of this paper is to show the effect of using high-resolution TFD kernels, in lieu of spectrogram, on fall detection. We focus on the extended modified B-distribution (EMBD) and exploit the level of details it provides as compared with the coarse and smoothed time-frequency signatures offered by spectrograms.

  12. Time-Frequency Analysis of the Dispersion of Lamb Modes

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Seale, Michael D.; Smith, Barry T.

    1999-01-01

    Accurate knowledge of the velocity dispersion of Lamb modes is important for ultrasonic nondestructive evaluation methods used in detecting and locating flaws in thin plates and in determining their elastic stiffness coefficients. Lamb mode dispersion is also important in the acoustic emission technique for accurately triangulating the location of emissions in thin plates. In this research, the ability to characterize Lamb mode dispersion through a time-frequency analysis (the pseudo-Wigner-Ville distribution) was demonstrated. A major advantage of time-frequency methods is the ability to analyze acoustic signals containing multiple propagation modes, which overlap and superimpose in the time domain signal. By combining time-frequency analysis with a broadband acoustic excitation source, the dispersion of multiple Lamb modes over a wide frequency range can be determined from as little as a single measurement. In addition, the technique provides a direct measurement of the group velocity dispersion. The technique was first demonstrated in the analysis of a simulated waveform in an aluminum plate in which the Lamb mode dispersion was well known. Portions of the dispersion curves of the AO, A I , So, and S2 Lamb modes were obtained from this one waveform. The technique was also applied for the analysis of experimental waveforms from a unidirectional graphite/epoxy composite plate. Measurements were made both along and perpendicular to the fiber direction. In this case, the signals contained only the lowest order symmetric and antisymmetric modes. A least squares fit of the results from several source to detector distances was used. Theoretical dispersion curves were calculated and are shown to be in good agreement with experimental results.

  13. Time-Frequency Analysis of the Dispersion of Lamb Modes

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Seale, Michael D.; Smith, Barry T.

    1999-01-01

    Accurate knowledge of the velocity dispersion of Lamb modes is important for ultrasonic nondestructive evaluation methods used in detecting and locating flaws in thin plates and in determining their elastic stiffness coefficients. Lamb mode dispersion is also important in the acoustic emission technique for accurately triangulating the location of emissions in thin plates. In this research, the ability to characterize Lamb mode dispersion through a time-frequency analysis (the pseudo Wigner-Ville distribution) was demonstrated. A major advantage of time-frequency methods is the ability to analyze acoustic signals containing multiple propagation modes, which overlap and superimpose in the time domain signal. By combining time-frequency analysis with a broadband acoustic excitation source, the dispersion of multiple Lamb modes over a wide frequency range can be determined from as little as a single measurement. In addition, the technique provides a direct measurement of the group velocity dispersion. The technique was first demonstrated in the analysis of a simulated waveform in an aluminum plate in which the Lamb mode dispersion was well known. Portions of the dispersion curves of the A(sub 0), A(sub 1), S(sub 0), and S(sub 2)Lamb modes were obtained from this one waveform. The technique was also applied for the analysis of experimental waveforms from a unidirectional graphite/epoxy composite plate. Measurements were made both along, and perpendicular to the fiber direction. In this case, the signals contained only the lowest order symmetric and antisymmetric modes. A least squares fit of the results from several source to detector distances was used. Theoretical dispersion curves were calculated and are shown to be in good agreement with experimental results.

  14. Accurate time-frequency-wavenumber analysis to study coda waves

    NASA Astrophysics Data System (ADS)

    Schisselé, Estelle; Guilbert, Jocelyn; Gaffet, Stéphane; Cansi, Yves

    2004-08-01

    An accurate method is developed to characterize the seismic coda phases recorded by small-aperture arrays. The coda is modelled as a superposition of several interfering wavelets identified by their arrival time, frequency content, backazimuth and apparent velocity of propagation. The wavelets are caused by the diffraction and refraction of the direct wavefield by heterogeneities of the propagation medium. The deterministic modelling is different from the statistical one generally used to retrieve mean parameters of the medium. As the complexity of the medium increases, separation of interfering wavelets needs an accurate time-frequency-wavenumber decomposition method that consists of detection and characterization of the different coherent wavelets propagating through the array. Detection is realized by mean time-frequency decomposition, based on the ridges algorithm. The MUltiple SIgnal Classification (MUSIC) algorithm, allowing a higher separation of simultaneous wavelets in the wavenumber domain, is then used to characterize the propagation parameters of the detected components. An optimal use of the MUSIC algorithm assumes the knowledge of the number of sources that simultaneously propagate through the array. The new iterative technique presented here allows the automatic determination of this number of sources. This methodology is applied to synthetic signals simulated in a heterogeneous medium. Results obtained show that: (i) the diffracted wavefield may be more energetic than the primary direct one and (ii) the relative energy diffracted by each heterogeneity is strongly dependent on the location of the array within the medium. The well-controlled results obtained for the synthetic examples allow interpretations of the observations made during the Annot experiment in the southern French Alps in 1998, where four small-aperture arrays were deployed, with small distances between each array (~10 km). The time-azimuth-velocity evolutions determined for the earthquakes recorded during this experiment are used to characterize the heterogeneous structures of the medium.

  15. A time-frequency classifier for human gait recognition

    NASA Astrophysics Data System (ADS)

    Mobasseri, Bijan G.; Amin, Moeness G.

    2009-05-01

    Radar has established itself as an effective all-weather, day or night sensor. Radar signals can penetrate walls and provide information on moving targets. Recently, radar has been used as an effective biometric sensor for classification of gait. The return from a coherent radar system contains a frequency offset in the carrier frequency, known as the Doppler Effect. The movements of arms and legs give rise to micro Doppler which can be clearly detailed in the time-frequency domain using traditional or modern time-frequency signal representation. In this paper we propose a gait classifier based on subspace learning using principal components analysis(PCA). The training set consists of feature vectors defined as either time or frequency snapshots taken from the spectrogram of radar backscatter. We show that gait signature is captured effectively in feature vectors. Feature vectors are then used in training a minimum distance classifier based on Mahalanobis distance metric. Results show that gait classification with high accuracy and short observation window is achievable using the proposed classifier.

  16. Cluster Prototypes and Fuzzy Memberships Jointly Leveraged Cross-Domain Maximum Entropy Clustering.

    PubMed

    Qian, Pengjiang; Jiang, Yizhang; Deng, Zhaohong; Hu, Lingzhi; Sun, Shouwei; Wang, Shitong; Muzic, Raymond F

    2016-01-01

    The classical maximum entropy clustering (MEC) algorithm usually cannot achieve satisfactory results in the situations where the data is insufficient, incomplete, or distorted. To address this problem, inspired by transfer learning, the specific cluster prototypes and fuzzy memberships jointly leveraged (CPM-JL) framework for cross-domain MEC (CDMEC) is firstly devised in this paper, and then the corresponding algorithm referred to as CPM-JL-CDMEC and the dedicated validity index named fuzzy memberships-based cross-domain difference measurement (FM-CDDM) are concurrently proposed. In general, the contributions of this paper are fourfold: 1) benefiting from the delicate CPM-JL framework, CPM-JL-CDMEC features high-clustering effectiveness and robustness even in some complex data situations; 2) the reliability of FM-CDDM has been demonstrated to be close to well-established external criteria, e.g., normalized mutual information and rand index, and it does not require additional label information. Hence, using FM-CDDM as a dedicated validity index significantly enhances the applicability of CPM-JL-CDMEC under realistic scenarios; 3) the performance of CPM-JL-CDMEC is generally better than, at least equal to, that of MEC because CPM-JL-CDMEC can degenerate into the standard MEC algorithm after adopting the proper parameters, and which avoids the issue of negative transfer; and 4) in order to maximize privacy protection, CPM-JL-CDMEC employs the known cluster prototypes and their associated fuzzy memberships rather than the raw data in the source domain as prior knowledge. The experimental studies thoroughly evaluated and demonstrated these advantages on both synthetic and real-life transfer datasets. PMID:26684257

  17. Postural tachycardia syndrome: time frequency mapping

    NASA Technical Reports Server (NTRS)

    Novak, V.; Novak, P.; Opfer-Gehrking, T. L.; Low, P. A.

    1996-01-01

    Orthostatic tachycardia is common but its specificity remains uncertain. Our preliminary work suggested that using autonomic function testing in conjunction with time-frequency mapping (TFM), it might be possible to characterize a subset of the postural tachycardia syndrome (POTS), that is due to a restricted autonomic neuropathy. We describe 20 patients (17 women and 3 men, aged 14-43 years) with florid POTS and 20 controls (14 women and 6 men, aged 20-41 years). Autonomic failure was quantified by its distribution (cardiovagal, adrenergic and sudomotor) and severity, a symptom profile was generated, and spectral indices, based on modified Wigner distribution during rest and head-up tilt (80 degrees) were evaluated. During tilt-up POTS patients differed from controls by an excessive heart rate (> 130 bpm) (P < 0.001), and higher diastolic pressure (P < 0.01). During rest, cardiovagal oscillations (at respiratory frequencies [RF]) and slow rhythms at nonrespiratory frequencies (NONRF) (from 0.01 to 0.07 Hz) in R-R intervals (RRI) (P < 0.01) were reduced. Both RF and NONRF rhythms in RRI were further blunted with tilt-up (P < 0.001). Slow adrenergic vasomotor rhythms in blood pressure (BP) (approximately 0.07 Hz) surged with tilt-up and returned to normal levels afterwards. The index of sympatho-vagal balance (NONRF-Systolic BP (SBP)/RF-RRI) was dramatically increased in POTS (P < 0.001). Distal postganglionic sudomotor failure was observed, and impairment of the BP responses to the Valsalva maneuver (phase II) suggested peripheral adrenergic dysfunction. Persistent orthostatic dizziness, tiredness, gastrointestinal symptoms and palpitations were common in POTS patients. It is possible to identify a subset of POTS patients who have a length-dependent autonomic neuropathy, affecting the peripheral adrenergic and cardiovagal fibers, with relative preservation of cardiac adrenergic fibers.

  18. Measurement Epistemology and Time-Frequency Conjugate Spaces

    NASA Astrophysics Data System (ADS)

    Roychoudhuri, Chandrasekhar

    2010-05-01

    We present the critical steps involved in any measurement process, which tell us that force-free and intervention-free measurements are not possible. We add to this the NIW-principle, Non-Interference of Waves, which has been neglected by us for centuries even though it is obvious from careful observations of crossing of all material based waves and light beams. Then we underscore that the foundational assumption behind the time-frequency Fourier theorem does not represent any physical reality even though mathematical computation does give the desired results. It assumes that simple superposition of monochromatic Fourier waves, by themselves, can generate time finite pulses due to interference. Unfortunately, the NIW-principle forbids it. Founders of quantum physics, oblivious of the existence of the NIW-principle, assumed that superposition of light beams produce the observed fringes. In reality, the superposition effects become observable because the quantized detectors carry out the summation of the joint stimulations. Thus, quantum physicists mistakenly assigned the quantum behavior of detectors on to light (photons). Based on these observations, we underscore that the ultimate purpose of physical theories is to facilitate the visualization of the invisible interaction processes, rather than simply model the measured data, as is customary now.

  19. Wavelet analysis and time-frequency distributions of the body surface ECG before and after angioplasty.

    PubMed

    Gramatikov, B; Brinker, J; Yi-chun, S; Thakor, N V

    2000-06-01

    In a pilot study, electrocardiographic (ECG) recordings of patients with left and right coronary stenosis taken before and after angioplasty were analyzed using the continuous wavelet transform. Time-frequency distributions were obtained for different leads in order to examine the dynamics of the QRS-spectrum and establish features specific of ischemia in the time-frequency domain. We found relevant changes in the mid-frequency range, reflecting the ECG's response to percutaneous transluminal coronary angioplasty (PTCA). The changes appeared in ECG leads close to ischemic zones of the myocardium. Time-frequency distributions of the ECG during the QRS may thus become another electrocardiographic indicator of ischemia, alternative to ST-level in standard ECG or body surface mapping. The paper demonstrates the ability of the continuous wavelet transform to detect short lasting events of low amplitude superimposed on large signal deflections. PMID:10764935

  20. Time-frequency beamforming for nondestructive evaluations of plate using ultrasonic Lamb wave

    NASA Astrophysics Data System (ADS)

    Han, Je-Heon; Kim, Yong-Joe

    2015-03-01

    The objective of this study is to detect structural defect locations in a plate by exciting the plate with a specific ultrasonic Lamb wave and recording reflective wave signals using a piezoelectric transducer array. For the purpose of eliminating the effects of the direct excitation signals as well as the boundary-reflected wave signals, it is proposed to improve a conventional MUSIC beamforming procedure by processing the measured signals in the time-frequency domain. In addition, a normalized, damped, cylindrical 2-D steering vector is proposed to increase the spatial resolution of time-frequency MUSIC power results. A cross-shaped array is selected to further improve the spatial resolution and to avoid mirrored virtual image effects. Here, it is experimentally demonstrated that the proposed time-frequency MUSIC beamforming procedure can be used to identify structural defect locations on an aluminum plate by distinguishing the defect-induced waves from the excitation-generated and boundary-reflected waves.

  1. Carbon financial markets: A time-frequency analysis of CO2 prices

    NASA Astrophysics Data System (ADS)

    Sousa, Rita; Aguiar-Conraria, Luís; Soares, Maria Joana

    2014-11-01

    We characterize the interrelation of CO2 prices with energy prices (electricity, gas and coal), and with economic activity. Previous studies have relied on time-domain techniques, such as Vector Auto-Regressions. In this study, we use multivariate wavelet analysis, which operates in the time-frequency domain. Wavelet analysis provides convenient tools to distinguish relations at particular frequencies and at particular time horizons. Our empirical approach has the potential to identify relations getting stronger and then disappearing over specific time intervals and frequencies. We are able to examine the coherency of these variables and lead-lag relations at different frequencies for the time periods in focus.

  2. Joint Entropy for Space and Spatial Frequency Domains Estimated from Psychometric Functions of Achromatic Discrimination

    PubMed Central

    Silveira, Vladímir de Aquino; Souza, Givago da Silva; Gomes, Bruno Duarte; Rodrigues, Anderson Raiol; Silveira, Luiz Carlos de Lima

    2014-01-01

    We used psychometric functions to estimate the joint entropy for space discrimination and spatial frequency discrimination. Space discrimination was taken as discrimination of spatial extent. Seven subjects were tested. Gábor functions comprising unidimensionalsinusoidal gratings (0.4, 2, and 10 cpd) and bidimensionalGaussian envelopes (1°) were used as reference stimuli. The experiment comprised the comparison between reference and test stimulithat differed in grating's spatial frequency or envelope's standard deviation. We tested 21 different envelope's standard deviations around the reference standard deviation to study spatial extent discrimination and 19 different grating's spatial frequencies around the reference spatial frequency to study spatial frequency discrimination. Two series of psychometric functions were obtained for 2%, 5%, 10%, and 100% stimulus contrast. The psychometric function data points for spatial extent discrimination or spatial frequency discrimination were fitted with Gaussian functions using the least square method, and the spatial extent and spatial frequency entropies were estimated from the standard deviation of these Gaussian functions. Then, joint entropy was obtained by multiplying the square root of space extent entropy times the spatial frequency entropy. We compared our results to the theoretical minimum for unidimensional Gábor functions, 1/4? or 0.0796. At low and intermediate spatial frequencies and high contrasts, joint entropy reached levels below the theoretical minimum, suggesting non-linear interactions between two or more visual mechanisms. We concluded that non-linear interactions of visual pathways, such as the M and P pathways, could explain joint entropy values below the theoretical minimum at low and intermediate spatial frequencies and high contrasts. These non-linear interactions might be at work at intermediate and high contrasts at all spatial frequencies once there was a substantial decrease in joint entropy for these stimulus conditions when contrast was raised. PMID:24466158

  3. Preamble-based frequency-domain joint CFO and STO estimation for OQAM-based filter bank multicarrier

    NASA Astrophysics Data System (ADS)

    Caekenberghe, Stijn Van; Bourdoux, André; der Perre, Liesbet Van; Louveaux, Jérôme

    2014-12-01

    Filter bank multicarrier systems, similarly to orthogonal frequency division multiplexing (OFDM), are very sensitive to carrier frequency offset (CFO) and symbol timing offset (STO). In this paper, a low-complexity preamble-based joint CFO and STO technique is presented. It is based on a relatively long preamble in order to improve the CFO estimation performance as well as avoid interference coming from the data following this preamble. After CFO and STO correction, the preamble can be reused to estimate the channel. Unlike most current techniques, the CFO and STO estimation occurs in the frequency domain. This allows for a low-complexity estimation with respect to time-domain techniques and, as will be shown by simulations, provide even better performance in a reasonable range. The drawback however is that the estimation range is shorter. Specifically, for large STOs (and to a smaller extent large CFOs), the performance decreases below time-domain estimations. Two versions of the STO estimation technique will be presented, the second one being an approximation of the first one, making it less complex yet also less precise. The performance is assessed by means of computer simulations, testing for both large and small STOs, and compared with existing techniques.

  4. Detailed Vibration Analysis of Pinion Gear with Time-Frequency Methods

    NASA Technical Reports Server (NTRS)

    Mosher, Marianne; Pryor, Anna H.; Lewicki, David G.

    2003-01-01

    In this paper, the authors show a detailed analysis of the vibration signal from the destructive testing of a spiral bevel gear and pinion pair containing seeded faults. The vibration signal is analyzed in the time domain, frequency domain and with four time-frequency transforms: the Short Time Frequency Transform (STFT), the Wigner-Ville Distribution with the Choi-Williams kernel (WV-CW), the Continuous Wavelet' Transform (CWT) and the Discrete Wavelet Transform (DWT). Vibration data of bevel gear tooth fatigue cracks, under a variety of operating load levels and damage conditions, are analyzed using these methods. A new metric for automatic anomaly detection is developed and can be produced from any systematic numerical representation of the vibration signals. This new metric reveals indications of gear damage with all of the time-frequency transforms, as well as time and frequency representations, on this data set. Analysis with the CWT detects changes in the signal at low torque levels not found with the other transforms. The WV-CW and CWT use considerably more resources than the STFT and the DWT. More testing of the new metric is needed to determine its value for automatic anomaly detection and to develop fault detection methods for the metric.

  5. Instantaneous frequency and time-frequency signature estimation using compressive sensing

    NASA Astrophysics Data System (ADS)

    Jokanovi?, Branka; Amin, Moeness; Stankovi?, Srdjan

    2013-05-01

    This paper considers compressive sensing for time-frequency signal representation (TFSR) of nonstationary radar signals which can be considered as instantaneously narrowband. Under-sampling and random sampling of the signal stem from avoiding aliasing and relaxing Nyquist sampling constraints. Unlike previous work on compressive sensing (CS) and TFSR based on the ambiguity function, reduced observations in the underlying problem are time-domain data. In the reconstruction process, Orthogonal Matching Pursuit (OMP) is used. Since the frequency index in the first iteration of OMP is the same as the one obtained by finding the frequency position of the highest Spectrogram peak, it becomes necessary to consider several OMP iterations to improve over Spectrograms performance. We examine various methods for estimating IF from higher number of OMP iterations, including the S-method. The paper also applies CS for signal time-frequency signature estimations corresponding to human gait radar returns.

  6. Comparison of Signals from Gravitational Wave Detectors with Instantaneous Time-Frequency Maps

    NASA Technical Reports Server (NTRS)

    Stroeer, A.; Blackburn, L.; Camp, J.

    2011-01-01

    Gravitational wave astronomy relies on the use of multiple detectors, so that coincident detections may distinguish real signals from instrumental artifacts, and also so that relative timing of signals can provide the sky position of sources. We show that the comparison of instantaneous time-frequency and time-amplitude maps provided by the Hilbert-Huang Transform (HHT) can be used effectively for relative signal timing of common signals, to discriminate between the case of identical coincident signals and random noise coincidences and to provide a classification of signals based on their time-frequency trajectories. The comparison is done with a X(sup 2) goodness-offit method which includes contributions from both the instantaneous amplitude and frequency components of the HHT to match two signals in the time domain. This approach naturally allows the analysis of waveforms with strong frequency modulation.

  7. [The research on time-frequency detection method of respiratory component in ballistocardiogram signal].

    PubMed

    Jiang, Fangfang; Wang, Xu; Yang, Dan

    2012-06-01

    Based on the fact that the respiratory component modulates the cardiac cycle component in the ballistocardiogram (BCG) signal, we propose a method that detects respiratory with time-frequency analysis for the sitting ballistocardiography system. Firstly, we demodulated the BCG signal by using the variable frequency complex demodulation (VFCDM) to obtain the output for different center frequency of interest. Then we calculated the instantaneous frequencies and the instantaneous amplitudes by the time-frequency representation. We reconstructed the time-domain waveform of respiratory at last. In order to verify the feasibility and accuracy of this method, we applied wavelet transform and nasal thermistor signal to compare qualitatively and quantitatively. The simulation results showed that the proposed method could detect the respiratory rate from BCG signal more accurately, which provided meaningful attempt for monitoring the multiple physiological parameters synchronously and unconsciously. PMID:22826926

  8. Electrocardiogram Signal and Linear Time-Frequency Transforms

    NASA Astrophysics Data System (ADS)

    Krishna, B. T.

    2014-12-01

    The diagnostic analysis of non-stationary multi component signals such as electrocardiogram (ECG) involves the use of time-frequency transforms. So, the application of time-frequency transforms to an ECG signal is an important problem of research. In this paper, initially, linear transforms like short time Fourier transform, continuous wavelet transforms, s-transform etc. are revisited. Then the application of these transforms to normal and abnormal ECG signals is illustrated. It has been observed that s-transform provides better time and frequency resolution compared to other linear transforms. The fractional Fourier transform provides rotation to the spectrogram representation.

  9. A TIME-FREQUENCY SEGMENTAL NEURAL NETWORK FOR PHONEME RECOGNITION

    E-print Network

    Svendsen, Torbjørn

    A TIME-FREQUENCY SEGMENTAL NEURAL NETWORK FOR PHONEME RECOGNITION Anjan Basu and Torbjtirn Svendsen of a segmental neural network (SNN) [l] in a hybrid HMM/ANN sys- tem for automatic speech recognition as it shows to combine the good features of both HMMs and ANNs This work was supported by a fellowship granted

  10. Nonlinear Time-Frequency Control Theory with Applications 

    E-print Network

    Liu, Mengkun 1978-

    2012-10-04

    is demonstrated through the multi-variable control of a micro-milling system. The research is of a broad impact on the control of a wide range of nonlinear and chaotic systems. The implications of the nonlinear time-frequency control theory in cutting, micro-machining...

  11. Time-frequency properties of electroencephalogram during induction of anesthesia.

    PubMed

    Kortelainen, Jukka; Koskinen, Miika; Mustola, Seppo; Seppänen, Tapio

    2008-12-01

    A method for detailed description of the time-frequency characteristics of electroencephalogram during induction of anesthesia is proposed. The method, based on averaging of time-normalized smoothed pseudo-Wigner-Ville distributions, is applied to data recorded from nine patients undergoing propofol anesthesia. An extensive representation of the frequency progression pattern related to the induction of anesthesia is given and the time-frequency characteristics that are consistent/not consistent between patients are determined. It is also illustrated how four different clinical end-points, generally used in the assessment of the depth of anesthesia, can be related to different phases of the frequency progression pattern. The method presented has importance in providing information about the neurophysiological phenomenon during induction of anesthesia and can therefore be used in the development of new monitoring algorithms. PMID:18835327

  12. Time-frequency analysis of laser weld signature

    NASA Astrophysics Data System (ADS)

    Sun, Allen S.; Kannatey-Asibu, Elijah, Jr.; Williams, William J.; Gartner, Mark

    2001-11-01

    Reliable monitoring methods are essential for maintaining a high level of quality control in laser welding. In industrial processes, monitoring systems allow for quick decisions on the quality of the weld, allowing for high productions rates and reducing overall cost due to scrap. A monitoring system using infrared, ultraviolet, audible sound, and acoustic emission was implemented for monitoring CO2 laser welds in real-time. The signals were analyzed using time-frequency analysis techniques. The time-frequency distribution using the Choi-Williams kernel was calculated, and the resulting distributions were analyzed using the Renyi information distribution. Results for porosity monitoring showed that an acoustic emission sensor held the most promise with 100% classification in two weld studies. These encouraging results led to a second study for monitoring of weld penetration and in the second case, infrared, ultraviolet, and audible sound showed the most promise with 100% classification for both laboratory and industrial data.

  13. Time-Frequency Approach for Stochastic Signal Detection

    SciTech Connect

    Ghosh, Ripul; Akula, Aparna; Kumar, Satish; Sardana, H. K.

    2011-10-20

    The detection of events in a stochastic signal has been a subject of great interest. One of the oldest signal processing technique, Fourier Transform of a signal contains information regarding frequency content, but it cannot resolve the exact onset of changes in the frequency, all temporal information is contained in the phase of the transform. On the other hand, Spectrogram is better able to resolve temporal evolution of frequency content, but has a trade-off in time resolution versus frequency resolution in accordance with the uncertainty principle. Therefore, time-frequency representations are considered for energetic characterisation of the non-stationary signals. Wigner Ville Distribution (WVD) is the most prominent quadratic time-frequency signal representation and used for analysing frequency variations in signals.WVD allows for instantaneous frequency estimation at each data point, for a typical temporal resolution of fractions of a second. This paper through simulations describes the way time frequency models are applied for the detection of event in a stochastic signal.

  14. Time-frequency analysis and Harmonic Gaussian Functions

    E-print Network

    Tokiniaina Ranaivoson; Raoelina Andriambololona; Rakotoson Hanitriarivo

    2013-08-08

    A method for time-frequency analysis is given. The approach utilizes properties of Gaussian distribution, properties of Hermite polynomials and Fourier analysis. We begin by the definitions of a set of functions called harmonic Gaussian functions. Then these functions are used to define a set of transformations,noted T_n, which associate to a function {\\psi},of the time variable t, a set of functions {\\Psi}_n which depend on time, frequency and frequency (or time) standard deviation. Some properties of the transformations T_n and the functions {\\Psi}_n are given. It is proved in particular that the square of the modulus of each function {\\Psi}_n can be interpreted as a representation of the energy distribution of the signal, represented by the function {\\psi}, in the time-frequency plane for a given value of the frequency (or time) standard deviation. It is also shown that the function {\\psi}, can be recovered from the functions{\\Psi}_n.

  15. Detecting fixation on a target using time-frequency distributions of a retinal birefringence scanning signal

    PubMed Central

    2013-01-01

    Background The fovea, which is the most sensitive part of the retina, is known to have birefringent properties, i.e. it changes the polarization state of light upon reflection. Existing devices use this property to obtain information on the orientation of the fovea and the direction of gaze. Such devices employ specific frequency components that appear during moments of fixation on a target. To detect them, previous methods have used solely the power spectrum of the Fast Fourier Transform (FFT), which, unfortunately, is an integral method, and does not give information as to where exactly the events of interest occur. With very young patients who are not cooperative enough, this presents a problem, because central fixation may be present only during very short-lasting episodes, and can easily be missed by the FFT. Method This paper presents a method for detecting short-lasting moments of central fixation in existing devices for retinal birefringence scanning, with the goal of a reliable detection of eye alignment. Signal analysis is based on the Continuous Wavelet Transform (CWT), which reliably localizes such events in the time-frequency plane. Even though the characteristic frequencies are not always strongly expressed due to possible artifacts, simple topological analysis of the time-frequency distribution can detect fixation reliably. Results In all six subjects tested, the CWT allowed precise identification of both frequency components. Moreover, in four of these subjects, episodes of intermittent but definitely present central fixation were detectable, similar to those in Figure 4. A simple FFT is likely to treat them as borderline cases, or entirely miss them, depending on the thresholds used. Conclusion Joint time-frequency analysis is a powerful tool in the detection of eye alignment, even in a noisy environment. The method is applicable to similar situations, where short-lasting diagnostic events need to be detected in time series acquired by means of scanning some substrate along a specific path. PMID:23668264

  16. A visual parallel-BCI speller based on the time-frequency coding strategy

    NASA Astrophysics Data System (ADS)

    Xu, Minpeng; Chen, Long; Zhang, Lixin; Qi, Hongzhi; Ma, Lan; Tang, Jiabei; Wan, Baikun; Ming, Dong

    2014-04-01

    Objective. Spelling is one of the most important issues in brain-computer interface (BCI) research. This paper is to develop a visual parallel-BCI speller system based on the time-frequency coding strategy in which the sub-speller switching among four simultaneously presented sub-spellers and the character selection are identified in a parallel mode. Approach. The parallel-BCI speller was constituted by four independent P300+SSVEP-B (P300 plus SSVEP blocking) spellers with different flicker frequencies, thereby all characters had a specific time-frequency code. To verify its effectiveness, 11 subjects were involved in the offline and online spellings. A classification strategy was designed to recognize the target character through jointly using the canonical correlation analysis and stepwise linear discriminant analysis. Main results. Online spellings showed that the proposed parallel-BCI speller had a high performance, reaching the highest information transfer rate of 67.4 bit min-1, with an average of 54.0 bit min-1 and 43.0 bit min-1 in the three rounds and five rounds, respectively. Significance. The results indicated that the proposed parallel-BCI could be effectively controlled by users with attention shifting fluently among the sub-spellers, and highly improved the BCI spelling performance.

  17. Time-frequency analysis of the bistatic acoustic scattering from a spherical elastic shell.

    PubMed

    Anderson, Shaun D; Sabra, Karim G; Zakharia, Manell E; Sessarego, Jean-Pierre

    2012-01-01

    The development of low-frequency sonar systems, using, for instance, a network of autonomous systems in unmanned vehicles, provides a practical means for bistatic measurements (i.e., when the source and receiver are widely separated) allowing for multiple viewpoints of the target of interest. Time-frequency analysis, in particular, Wigner-Ville analysis, takes advantage of the evolution time dependent aspect of the echo spectrum to differentiate a man-made target, such as an elastic spherical shell, from a natural object of the similar shape. A key energetic feature of fluid-loaded and thin spherical shell is the coincidence pattern, also referred to as the mid-frequency enhancement (MFE), that results from antisymmetric Lamb-waves propagating around the circumference of the shell. This article investigates numerically the bistatic variations of the MFE with respect to the monostatic configuration using the Wigner-Ville analysis. The observed time-frequency shifts of the MFE are modeled using a previously derived quantitative ray theory by Zhang et al. [J. Acoust. Soc. Am. 91, 1862-1874 (1993)] for spherical shell's scattering. Additionally, the advantage of an optimal array beamformer, based on joint time delays and frequency shifts is illustrated for enhancing the detection of the MFE recorded across a bistatic receiver array when compared to a conventional time-delay beamformer. PMID:22280581

  18. Human Time-Frequency Acuity Beats the Fourier Uncertainty Principle

    NASA Astrophysics Data System (ADS)

    Oppenheim, Jacob N.; Magnasco, Marcelo O.

    2013-01-01

    The time-frequency uncertainty principle states that the product of the temporal and frequency extents of a signal cannot be smaller than 1/(4?). We study human ability to simultaneously judge the frequency and the timing of a sound. Our subjects often exceeded the uncertainty limit, sometimes by more than tenfold, mostly through remarkable timing acuity. Our results establish a lower bound for the nonlinearity and complexity of the algorithms employed by our brains in parsing transient sounds, rule out simple “linear filter” models of early auditory processing, and highlight timing acuity as a central feature in auditory object processing.

  19. Detecting LISA sources using time-frequency techniques

    E-print Network

    Jonathan R Gair; Gareth Jones

    2007-03-06

    The planned Laser Interferometer Space Antenna (LISA) will detect gravitational wave signals from a wide range of sources. However, disentangling individual signals from the source-dominated data stream is a challenging problem and the focus of much current research. The problems are particularly acute for detection of extreme mass ratio inspirals (EMRIs), for which the instantaneous signal amplitude is an order of magnitude below the level of the instrumental noise, and the parameter space of possible signals is too large to permit fully-coherent matched filtering. One possible approach is to attempt to identify sources in a time-frequency spectrogram of the LISA data. This is a computationally cheap method that may be useful as a first stage in a hierarchical analysis. Initial results, evaluated using a significantly simplified model of the LISA data stream, suggest that time-frequency techniques might be able to detect the nearest few tens of EMRI events. In this proceedings article, we briefly outline the methods that have so far been applied to the problem, initial results and possible future directions for the research.

  20. Time-frequency methods for signal analysis in wind turbines

    NASA Astrophysics Data System (ADS)

    Kalista, Karel; Liska, Jindrich

    2015-11-01

    Since wind turbines became one of the most often source of renewable energy, appropriate health and condition monitoring systems are required. Especially proper monitoring of offshore plants is very significant because the accessibility is difficult and inspections are very costly. In comparison with conventional rotating machine vibration monitoring, where steady conditions and stationary signal are usually assumed, the wind turbines are characterized by unsteady conditions due to variable rotational speed. Hence the vibration signal is non-stationary and interpretation of signal signatures may be more complex. The common approach to analyze such non-stationary signals is the use of a time-frequency method, usually Short-Time Fourier Transform, which is the most popular one due to its simplicity. Nevertheless, there are other methods which can give a different view at the analyzed data and provide new information. This article investigates the potential use of some other time-frequency methods, namely Wavelet Transform, Wigner-Ville distribution and Hilbert-Huang transform in wind plants monitoring systems and apply these methods to real measured data with additional simulated bearing fault signal. Finally, the mentioned methods are compared based on computational complexity, readability and interpretability. Though the last two criteria are very subjective, Short-Time Fourier Transform was finally chosen as the most effective method followed by Wavelet Transform.

  1. Repeatability of an Ablation Source Using a Time-Frequency Representation

    NASA Astrophysics Data System (ADS)

    Luangvilai, Kritsakorn; Jacobs, Laurence J.

    2003-03-01

    Ultrasonic Lamb waves attenuate when propagating through viscoelastic plates. Experimental attenuation values are usually obtained with transducers by comparing measured time-domain signals at two different locations. However, this method can measure only a few points on the attenuation-frequency dispersion curves, and usually only for some specific mode. It has been shown that multi-mode dispersion curves (plus their associated energy distribution) can be obtained by operating on the transient, time-domain signals, generated and detected with laser ultrasonics. This technique uses proper signal processing technique, namely, a time-frequency representation (TFR). The current research uses a similar methodology for Lamb wave attenuation measurements which provides a series of attenuation values for many modes. As a first step, the laser source repeatability (both amplitude and frequency spectrum) must be verified. This research studies the variation of a laser ablation source by considering the surface wave propagating on an isotropic half-space. A series of experimental time-domain surface wave signals from different propagation distances are operated on with a TFR and compared in, strictly, propagation-distance-independent energy slowness-frequency domain. The amplitude constant is defined for comparison purposes. Also, the proposed signal processing technique is instituted in an error-free manner.

  2. Time-frequency characterization of interdependencies in nonstationary signals: application to epileptic EEG.

    PubMed

    Ansari-Asl, Karim; Bellanger, Jean-Jacques; Bartolomei, Fabrice; Wendling, Fabrice; Senhadji, Lotfi

    2005-07-01

    For the past decades, numerous works have been dedicated to the development of signal processing methods aimed at measuring the degree of association between electroencephalographic (EEG) signals. This interdependency parameter, which may be defined in various ways, is often used to characterize a functional coupling between different brain structures or regions during either normal or pathological processes. In this paper, we focus on the time-frequency characterization of the interdependency between signals. Particularly, we propose a novel estimator of the linear relationship between nonstationary signals based on the cross correlation of narrow band filtered signals. This estimator is compared to a more classical estimator based on the coherence function. In a simulation framework, results show that it may exhibit better statistical performances (bias and variance or mean square error) when a priori knowledge about time delay between signals is available. On real data (intracerebral EEG signals), results show that this estimator may also enhance the readability of the time-frequency representation of relationship and, thus, can improve the interpretation of nonstationary interdependencies in EEG signals. Finally, we illustrate the importance of characterizing the relationship in both time and frequency domains by comparing with frequency-independent methods (linear and nonlinear). PMID:16041985

  3. Time-frequency signal analysis for gearbox fault diagnosis using a generalized synchrosqueezing transform

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Liang, Ming

    2012-01-01

    The vibration data, especially those collected during the system run-up and run-down periods, contain rich information for gearbox condition monitoring. Time-frequency (TF) signal analysis is an effective tool to detect gearbox faults under varying shaft speed. However, the feature of the amplitude modulated-frequency modulated (AM-FM) gearbox fault signal usually cannot be directly extracted from the blurred time-frequency representation (TFR) caused by the time-varying frequency and noisy multicomponent measurement. As such, we propose to use a generalized synchrosqueezing transform (GST)-based TF method to detect and diagnose gearbox faults. With this method, the original vibration signal is first mapped into another analytical signal to facilitate synchrosqueezing of the TF picture. A time-scale domain restoration process is then applied to recover the instantaneous frequency profile with concentrated TFR. The gearbox fault, if any, can then be detected by observing the presence of the meshing frequency and sideband components in the TFR. The faulty gear can be identified via frequency relation analysis of AM-FM components. The proposed method is evaluated using both simulated and experimental gearbox vibration signals. The results show that the proposed approach is effective for gearbox condition monitoring.

  4. Cross Time-Frequency Analysis for Combining Information of Several Sources: Application to Estimation of Spontaneous Respiratory Rate from Photoplethysmography

    PubMed Central

    Peláez-Coca, M. D.; Orini, M.; Lázaro, J.; Bailón, R.; Gil, E.

    2013-01-01

    A methodology that combines information from several nonstationary biological signals is presented. This methodology is based on time-frequency coherence, that quantifies the similarity of two signals in the time-frequency domain. A cross time-frequency analysis method, based on quadratic time-frequency distribution, has been used for combining information of several nonstationary biomedical signals. In order to evaluate this methodology, the respiratory rate from the photoplethysmographic (PPG) signal is estimated. The respiration provokes simultaneous changes in the pulse interval, amplitude, and width of the PPG signal. This suggests that the combination of information from these sources will improve the accuracy of the estimation of the respiratory rate. Another target of this paper is to implement an algorithm which provides a robust estimation. Therefore, respiratory rate was estimated only in those intervals where the features extracted from the PPG signals are linearly coupled. In 38 spontaneous breathing subjects, among which 7 were characterized by a respiratory rate lower than 0.15 Hz, this methodology provided accurate estimates, with the median error {0.00; 0.98}?mHz ({0.00; 0.31}%) and the interquartile range error {4.88; 6.59}?mHz ({1.60; 1.92}%). The estimation error of the presented methodology was largely lower than the estimation error obtained without combining different PPG features related to respiration. PMID:24363777

  5. Multiple linear regression to estimate time-frequency electrophysiological responses in single trials

    PubMed Central

    Hu, L.; Zhang, Z.G.; Mouraux, A.; Iannetti, G.D.

    2015-01-01

    Transient sensory, motor or cognitive event elicit not only phase-locked event-related potentials (ERPs) in the ongoing electroencephalogram (EEG), but also induce non-phase-locked modulations of ongoing EEG oscillations. These modulations can be detected when single-trial waveforms are analysed in the time-frequency domain, and consist in stimulus-induced decreases (event-related desynchronization, ERD) or increases (event-related synchronization, ERS) of synchrony in the activity of the underlying neuronal populations. ERD and ERS reflect changes in the parameters that control oscillations in neuronal networks and, depending on the frequency at which they occur, represent neuronal mechanisms involved in cortical activation, inhibition and binding. ERD and ERS are commonly estimated by averaging the time-frequency decomposition of single trials. However, their trial-to-trial variability that can reflect physiologically-important information is lost by across-trial averaging. Here, we aim to (1) develop novel approaches to explore single-trial parameters (including latency, frequency and magnitude) of ERP/ERD/ERS; (2) disclose the relationship between estimated single-trial parameters and other experimental factors (e.g., perceived intensity). We found that (1) stimulus-elicited ERP/ERD/ERS can be correctly separated using principal component analysis (PCA) decomposition with Varimax rotation on the single-trial time-frequency distributions; (2) time-frequency multiple linear regression with dispersion term (TF-MLRd) enhances the signal-to-noise ratio of ERP/ERD/ERS in single trials, and provides an unbiased estimation of their latency, frequency, and magnitude at single-trial level; (3) these estimates can be meaningfully correlated with each other and with other experimental factors at single-trial level (e.g., perceived stimulus intensity and ERP magnitude). The methods described in this article allow exploring fully non-phase-locked stimulus-induced cortical oscillations, obtaining single-trial estimate of response latency, frequency, and magnitude. This permits within-subject statistical comparisons, correlation with pre-stimulus features, and integration of simultaneously-recorded EEG and fMRI. PMID:25665966

  6. Time-Frequency Analysis Reveals Pairwise Interactions in Insect Swarms.

    PubMed

    Puckett, James G; Ni, Rui; Ouellette, Nicholas T

    2015-06-26

    The macroscopic emergent behavior of social animal groups is a classic example of dynamical self-organization, and is thought to arise from the local interactions between individuals. Determining these interactions from empirical data sets of real animal groups, however, is challenging. Using multicamera imaging and tracking, we studied the motion of individual flying midges in laboratory mating swarms. By performing a time-frequency analysis of the midge trajectories, we show that the midge behavior can be segmented into two distinct modes: one that is independent and composed of low-frequency maneuvers, and one that consists of higher-frequency nearly harmonic oscillations conducted in synchrony with another midge. We characterize these pairwise interactions, and make a hypothesis as to their biological function. PMID:26197145

  7. Time-frequency analysis of synthetic aperture radar signals

    SciTech Connect

    Johnston, B.

    1996-08-01

    Synthetic aperture radar (SAR) has become an important tool for remote sensing of the environment. SAR is a set of digital signal processing algorithms that are used to focus the signal returned to the radar because radar systems in themselves cannot produce the high resolution images required in remote sensing applications. To reconstruct an image, several parameters must be estimated and the quality of output image depends on the degree of accuracy of these parameters. In this thesis, we derive the fundamental SAR algorithms and concentrate on the estimation of one of its critical parameters. We show that the common technique for estimating this particular parameter can sometimes lead to erroneous results and reduced quality images. We also employ time-frequency analysis techniques to examine variations in the radar signals caused by platform motion and show how these results can be used to improve output image quality.

  8. Time-frequency methods for structural health monitoring.

    PubMed

    Pyayt, Alexander L; Kozionov, Alexey P; Mokhov, Ilya I; Lang, Bernhard; Meijer, Robert J; Krzhizhanovskaya, Valeria V; Sloot, Peter M A

    2014-01-01

    Detection of early warning signals for the imminent failure of large and complex engineered structures is a daunting challenge with many open research questions. In this paper we report on novel ways to perform Structural Health Monitoring (SHM) of flood protection systems (levees, earthen dikes and concrete dams) using sensor data. We present a robust data-driven anomaly detection method that combines time-frequency feature extraction, using wavelet analysis and phase shift, with one-sided classification techniques to identify the onset of failure anomalies in real-time sensor measurements. The methodology has been successfully tested at three operational levees. We detected a dam leakage in the retaining dam (Germany) and "strange" behaviour of sensors installed in a Boston levee (UK) and a Rhine levee (Germany). PMID:24625740

  9. Time-Frequency Methods for Structural Health Monitoring †

    PubMed Central

    Pyayt, Alexander L.; Kozionov, Alexey P.; Mokhov, Ilya I.; Lang, Bernhard; Meijer, Robert J.; Krzhizhanovskaya, Valeria V.; Sloot, Peter M. A.

    2014-01-01

    Detection of early warning signals for the imminent failure of large and complex engineered structures is a daunting challenge with many open research questions. In this paper we report on novel ways to perform Structural Health Monitoring (SHM) of flood protection systems (levees, earthen dikes and concrete dams) using sensor data. We present a robust data-driven anomaly detection method that combines time-frequency feature extraction, using wavelet analysis and phase shift, with one-sided classification techniques to identify the onset of failure anomalies in real-time sensor measurements. The methodology has been successfully tested at three operational levees. We detected a dam leakage in the retaining dam (Germany) and “strange” behaviour of sensors installed in a Boston levee (UK) and a Rhine levee (Germany). PMID:24625740

  10. Time-Frequency Analysis Reveals Pairwise Interactions in Insect Swarms

    NASA Astrophysics Data System (ADS)

    Puckett, James G.; Ni, Rui; Ouellette, Nicholas T.

    2015-06-01

    The macroscopic emergent behavior of social animal groups is a classic example of dynamical self-organization, and is thought to arise from the local interactions between individuals. Determining these interactions from empirical data sets of real animal groups, however, is challenging. Using multicamera imaging and tracking, we studied the motion of individual flying midges in laboratory mating swarms. By performing a time-frequency analysis of the midge trajectories, we show that the midge behavior can be segmented into two distinct modes: one that is independent and composed of low-frequency maneuvers, and one that consists of higher-frequency nearly harmonic oscillations conducted in synchrony with another midge. We characterize these pairwise interactions, and make a hypothesis as to their biological function.

  11. Time-frequency analysis of functional optical mammographic images

    NASA Astrophysics Data System (ADS)

    Barbour, Randall L.; Graber, Harry L.; Schmitz, Christoph H.; Tarantini, Frank; Khoury, Georges; Naar, David J.; Panetta, Thomas F.; Lewis, Theophilus; Pei, Yaling

    2003-07-01

    We have introduced working technology that provides for time-series imaging of the hemoglobin signal in large tissue structures. In this study we have explored our ability to detect aberrant time-frequency responses of breast vasculature for subjects with Stage II breast cancer at rest and in response to simple provocations. The hypothesis being explored is that time-series imaging will be sensitive to the known structural and functional malformations of the tumor vasculature. Mammographic studies were conducted using an adjustable hemisheric measuring head containing 21 source and 21 detector locations (441 source-detector pairs). Simultaneous dual-wavelength studies were performed at 760 and 830 nm at a framing rate of ~2.7 Hz. Optical measures were performed on women lying prone with the breast hanging in a pendant position. Two class of measures were performed: (1) 20- minute baseline measure wherein the subject was at rest; (2) provocation studies wherein the subject was asked to perform some simple breathing maneuvers. Collected data were analyzed to identify the time-frequency structure and central tendencies of the detector responses and those of the image time series. Imaging data were generated using the Normalized Difference Method (Pei et al., Appl. Opt. 40, 5755-5769, 2001). Results obtained clearly document three classes of anomalies when compared to the normal contralateral breast. 1) Breast tumors exhibit altered oxygen supply/demand imbalance in response to an oxidative challenge (breath hold). 2) The vasomotor response of the tumor vasculature is mainly depressed and exhibits an altered modulation. 3) The affected area of the breast wherein the altered vasomotor signature is seen extends well beyond the limits of the tumor itself.

  12. Joint annotation of chromatin state and chromatin conformation reveals relationships among domain types and identifies domains of cell-type-specific expression

    PubMed Central

    Libbrecht, Maxwell W.; Ay, Ferhat; Hoffman, Michael M.; Gilbert, David M.; Bilmes, Jeffrey A.; Noble, William Stafford

    2015-01-01

    The genomic neighborhood of a gene influences its activity, a behavior that is attributable in part to domain-scale regulation. Previous genomic studies have identified many types of regulatory domains. However, due to the difficulty of integrating genomics data sets, the relationships among these domain types are poorly understood. Semi-automated genome annotation (SAGA) algorithms facilitate human interpretation of heterogeneous collections of genomics data by simultaneously partitioning the human genome and assigning labels to the resulting genomic segments. However, existing SAGA methods cannot integrate inherently pairwise chromatin conformation data. We developed a new computational method, called graph-based regularization (GBR), for expressing a pairwise prior that encourages certain pairs of genomic loci to receive the same label in a genome annotation. We used GBR to exploit chromatin conformation information during genome annotation by encouraging positions that are close in 3D to occupy the same type of domain. Using this approach, we produced a model of chromatin domains in eight human cell types, thereby revealing the relationships among known domain types. Through this model, we identified clusters of tightly regulated genes expressed in only a small number of cell types, which we term “specific expression domains.” We found that domain boundaries marked by promoters and CTCF motifs are consistent between cell types even when domain activity changes. Finally, we showed that GBR can be used to transfer information from well-studied cell types to less well-characterized cell types during genome annotation, making it possible to produce high-quality annotations of the hundreds of cell types with limited available data. PMID:25677182

  13. A new time-frequency analysis method for gyro signal denoising

    NASA Astrophysics Data System (ADS)

    Lu, Yanhong; Xu, Yefeng

    2006-11-01

    Gyro output signal is a non-stationary and time-varied time series mixed with noise. A new time-frequency analysis method for gyro de-noising, the empirical mode decomposition (EMD), is introduced. The non-stationary hybrid gyro signal is studied adaptively in the domain of time and frequency. First the hybrid signal is decomposed into finite intrinsic mode functions (IMF), then their frequency characteristic and the relationship between these IMFs and different gyro errors are studied deeply. Follow that a certain number of IMFs are eliminated and EMD's filter bank characteristic is achieved. After the ring laser gyro signal is processed by EMD and wavelet, Allan variance approach is applied to evaluate five kinds of gyro noise. By the conclusion, the EMD method is obviously more efficacious than wavelet in eliminating various kind of noise.

  14. Concatenative Text-to-Speech Synthesis Based on Prototype Waveform Interpolation (A Time Frequency Approach) 

    E-print Network

    Morais, Edmilson; Taylor, Paul; Violaro, Fabio

    This paper presents some preliminary methods to apply the Time- Frequency Interpolation technique - TFI [3] to concatenative text-to-speech synthesis. The TFI technique described here is a pitch-synchronous time-frequency ...

  15. Joint Inversion of Body-Wave Arrival Times and Surface-Wave Dispersion Data in the Wavelet Domain Constrained by Sparsity Regularization

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Fang, H.; Yao, H.; Maceira, M.; van der Hilst, R. D.

    2014-12-01

    Recently, Zhang et al. (2014, Pure and Appiled Geophysics) have developed a joint inversion code incorporating body-wave arrival times and surface-wave dispersion data. The joint inversion code was based on the regional-scale version of the double-difference tomography algorithm tomoDD. The surface-wave inversion part uses the propagator matrix solver in the algorithm DISPER80 (Saito, 1988) for forward calculation of dispersion curves from layered velocity models and the related sensitivities. The application of the joint inversion code to the SAFOD site in central California shows that the fault structure is better imaged in the new model, which is able to fit both the body-wave and surface-wave observations adequately. Here we present a new joint inversion method that solves the model in the wavelet domain constrained by sparsity regularization. Compared to the previous method, it has the following advantages: (1) The method is both data- and model-adaptive. For the velocity model, it can be represented by different wavelet coefficients at different scales, which are generally sparse. By constraining the model wavelet coefficients to be sparse, the inversion in the wavelet domain can inherently adapt to the data distribution so that the model has higher spatial resolution in the good data coverage zone. Fang and Zhang (2014, Geophysical Journal International) have showed the superior performance of the wavelet-based double-difference seismic tomography method compared to the conventional method. (2) For the surface wave inversion, the joint inversion code takes advantage of the recent development of direct inversion of surface wave dispersion data for 3-D variations of shear wave velocity without the intermediate step of phase or group velocity maps (Fang et al., 2014, Geophysical Journal International). A fast marching method is used to compute, at each period, surface wave traveltimes and ray paths between sources and receivers. We will test the new joint inversion code at the SAFOD site to compare its performance over the previous code. We will also select another fault zone such as the San Jacinto Fault Zone to better image its structure.

  16. Sparse Component Analysis Using Time-Frequency Representations for Operational Modal Analysis

    PubMed Central

    Qin, Shaoqian; Guo, Jie; Zhu, Changan

    2015-01-01

    Sparse component analysis (SCA) has been widely used for blind source separation(BSS) for many years. Recently, SCA has been applied to operational modal analysis (OMA), which is also known as output-only modal identification. This paper considers the sparsity of sources' time-frequency (TF) representation and proposes a new TF-domain SCA under the OMA framework. First, the measurements from the sensors are transformed to the TF domain to get a sparse representation. Then, single-source-points (SSPs) are detected to better reveal the hyperlines which correspond to the columns of the mixing matrix. The K-hyperline clustering algorithm is used to identify the direction vectors of the hyperlines and then the mixing matrix is calculated. Finally, basis pursuit de-noising technique is used to recover the modal responses, from which the modal parameters are computed. The proposed method is valid even if the number of active modes exceed the number of sensors. Numerical simulation and experimental verification demonstrate the good performance of the proposed method. PMID:25789492

  17. A wavelet based time-frequency analysis of wave packet fractional revivals

    NASA Astrophysics Data System (ADS)

    Ghosh, Suranjana; Banerji, Jagannath

    2007-06-01

    We show that the time-frequency analysis of the autocorrelation function based on its wavelet transform [1], is a better tool to resolve fractional revivals [2] of a wave packet than the usual time domain analysis. We study the above for two different systems like a Rydberg atom [3] and a diatomic molecular system [4] and show that the present method can resolve fractional revivals of higher order than what can be achieved by the time domain analysis. This advantage is crucial in reconstructing the initial state of the wave packet when its coherent structure is short-lived and decays before it is fully revived. References: [1] R. M. Rao and A. S. Bopardikar, Wavelet Transforms: Introduction to Theory and Applications (ADDISON-WESLEY, 2000). [2] I. Sh. Averbukh and N. F. Perelman, Phys. Lett. A 139, 449 (1989); R. W. Robinett, Phys. Rep. 392, 1 (2004) and references therein; J. Banerji and S. Ghosh, J. Phys. B 39, 1113 (2006). [3] Z. D. Gaeta and C. R. Stroud, Jr., Phys. Rev. A 42, 6308 (1990). [4] S. Ghosh, A. Chiruvelli, J. Banerji and P. K. Panigrahi, Phys. Rev. A 70, 053813 (2006).

  18. Ultrashort Pulse Characterization and Coherent Time-Frequency Light Processing

    NASA Astrophysics Data System (ADS)

    Radunsky, Aleksandr S.

    Over the past several decades ultrafast laser science and technology has evolved into an extensive and diverse yet still one of the most rapidly growing and developing areas of optics. This evolution has been one of mutual interdependence. Each current generation of technological innovations not only solves the specific problems it was designed for, but uncovers new application opportunities and enables the exploration of new basic research areas. In turn, these new challenges will give rise to the next generation of technological improvements born of the currently existing technologies and the advances in fundamental scientific knowledge and understanding. Ultrashort pulse characterization has always been an essential part of this ultrafast optics evolution. The thesis makes yet another contribution to it by describing the principle, design, construction, development and operation of a novel interferometric ultrashort pulse characterization device. It consists of a new implementation of spectral-shearing interferometry for reconstructing the electric field of ultrashort pulses, requiring only a single optical element to encode the temporal field of the pulse under test. The technique relies on an asymmetric group velocity matching type II sum frequency generation process in a single long nonlinear crystal. We analyze the performance of the device for a wide range of experimentally available input pulse parameters. The device --- potential building block for the future generations of ultrashort diagnostics --- proves a practical, elegant, compact, robust, and sensitive option for complete amplitude and phase ultrashort pulse characterization. As the femtosecond systems of increasingly larger bandwidth become a widespread reality, the detrimental effects of dispersion require careful consideration. Dispersive pulse distortion degrades longitudinal resolution of broadband interferometric imaging methods such as optical coherence tomography and low-coherence interferometry. We address the issue with a novel signal processing dispersion compensation method. This numerical technique improves the axial resolution without a priori knowledge of the material dispersive properties of the sample under consideration. The dispersion compensation is based on the generalized temporal fourth order field autoconvolution function computed from the readily available experimental interferometric scans and has an intuitive depiction in the time-frequency phase-space via the Wigner distribution function formalism.

  19. Time-Frequency Mixed-Norm Estimates: Sparse M/EEG imaging with non-stationary source activations

    PubMed Central

    Gramfort, A.; Strohmeier, D.; Haueisen, J.; Hämäläinen, M.; Kowalski, M.

    2013-01-01

    Magnetoencephalography (MEG) and electroencephalography (EEG) allow functional brain imaging with high temporal resolution. While solving the inverse problem independently at every time point can give an image of the active brain at every millisecond, such a procedure does not capitalize on the temporal dynamics of the signal. Linear inverse methods (Minimum-norm, dSPM, sLORETA, beamformers) typically assume that the signal is stationary: regularization parameter and data covariance are independent of time and the time varying signal-to-noise ratio (SNR). Other recently proposed non-linear inverse solvers promoting focal activations estimate the sources in both space and time while also assuming stationary sources during a time interval. However such an hypothesis only holds for short time intervals. To overcome this limitation, we propose time-frequency mixed-norm estimates (TF-MxNE), which use time-frequency analysis to regularize the ill-posed inverse problem. This method makes use of structured sparse priors defined in the time-frequency domain, offering more accurate estimates by capturing the non-stationary and transient nature of brain signals. State-of-the-art convex optimization procedures based on proximal operators are employed, allowing the derivation of a fast estimation algorithm. The accuracy of the TF-MxNE is compared to recently proposed inverse solvers with help of simulations and by analyzing publicly available MEG datasets. PMID:23291276

  20. An Improved Time-Frequency Analysis Method in Interference Detection for GNSS Receivers.

    PubMed

    Sun, Kewen; Jin, Tian; Yang, Dongkai

    2015-01-01

    In this paper, an improved joint time-frequency (TF) analysis method based on a reassigned smoothed pseudo Wigner-Ville distribution (RSPWVD) has been proposed in interference detection for Global Navigation Satellite System (GNSS) receivers. In the RSPWVD, the two-dimensional low-pass filtering smoothing function is introduced to eliminate the cross-terms present in the quadratic TF distribution, and at the same time, the reassignment method is adopted to improve the TF concentration properties of the auto-terms of the signal components. This proposed interference detection method is evaluated by experiments on GPS L1 signals in the disturbing scenarios compared to the state-of-the-art interference detection approaches. The analysis results show that the proposed interference detection technique effectively overcomes the cross-terms problem and also preserves good TF localization properties, which has been proven to be effective and valid to enhance the interference detection performance of the GNSS receivers, particularly in the jamming environments. PMID:25905704

  1. An Improved Time-Frequency Analysis Method in Interference Detection for GNSS Receivers

    PubMed Central

    Sun, Kewen; Jin, Tian; Yang, Dongkai

    2015-01-01

    In this paper, an improved joint time-frequency (TF) analysis method based on a reassigned smoothed pseudo Wigner–Ville distribution (RSPWVD) has been proposed in interference detection for Global Navigation Satellite System (GNSS) receivers. In the RSPWVD, the two-dimensional low-pass filtering smoothing function is introduced to eliminate the cross-terms present in the quadratic TF distribution, and at the same time, the reassignment method is adopted to improve the TF concentration properties of the auto-terms of the signal components. This proposed interference detection method is evaluated by experiments on GPS L1 signals in the disturbing scenarios compared to the state-of-the-art interference detection approaches. The analysis results show that the proposed interference detection technique effectively overcomes the cross-terms problem and also preserves good TF localization properties, which has been proven to be effective and valid to enhance the interference detection performance of the GNSS receivers, particularly in the jamming environments. PMID:25905704

  2. Local polynomial modeling of time-varying autoregressive models with application to time-frequency analysis of event-related EEG.

    PubMed

    Zhang, Z G; Hung, Y S; Chan, S C

    2011-03-01

    This paper proposes a new local polynomial modeling (LPM) method for identification of time-varying autoregressive (TVAR) models and applies it to time-frequency analysis (TFA) of event-related electroencephalogram (ER-EEG). The LPM method models the TVAR coefficients locally by polynomials and estimates the polynomial coefficients using weighted least-squares with a window having a certain bandwidth. A data-driven variable bandwidth selection method is developed to determine the optimal bandwidth that minimizes the mean squared error. The resultant time-varying power spectral density estimation of the signal is capable of achieving both high time resolution and high frequency resolution in the time-frequency domain, making it a powerful TFA technique for nonstationary biomedical signals like ER-EEG. Experimental results on synthesized signals and real EEG data show that the LPM method can achieve a more accurate and complete time-frequency representation of the signal. PMID:20977980

  3. Analysis and design of modified window shapes for S-transform to improve time-frequency localization

    NASA Astrophysics Data System (ADS)

    Ma, Jianping; Jiang, Jin

    2015-06-01

    This paper deals with window design issues for modified S-transform (MST) to improve the performance of time-frequency analysis (TFA). After analyzing the drawbacks of existing window functions, a window design technique is proposed. The technique uses a sigmoid function to control the window width in frequency domain. By proper selection of certain tuning parameters of a sigmoid function, windows with different width profiles can be obtained for multi-component signals. It is also interesting to note that the MST algorithm can be considered as a special case of a generalized method that adds a tunable shaping function to the standard window in frequency domain to meet specific frequency localization needs. The proposed design technique has been validated on a physical vibration test system using signals with different characteristics. The results have demonstrated that the proposed MST algorithm has superior time-frequency localization capabilities over standard ST, as well as other classical TFA methods. Subsequently, the proposed MST algorithm is applied to vibration monitoring of pipes in a water supply process controlled by a diaphragm pump for fault detection purposes.

  4. Hilbert-Huang transformation-based time-frequency analysis methods in biomedical signal applications.

    PubMed

    Lin, Chin-Feng; Zhu, Jin-De

    2012-03-01

    Hilbert-Huang transformation, wavelet transformation, and Fourier transformation are the principal time-frequency analysis methods. These transformations can be used to discuss the frequency characteristics of linear and stationary signals, the time-frequency features of linear and non-stationary signals, the time-frequency features of non-linear and non-stationary signals, respectively. The Hilbert-Huang transformation is a combination of empirical mode decomposition and Hilbert spectral analysis. The empirical mode decomposition uses the characteristics of signals to adaptively decompose them to several intrinsic mode functions. Hilbert transforms are then used to transform the intrinsic mode functions into instantaneous frequencies, to obtain the signal's time-frequency-energy distributions and features. Hilbert-Huang transformation-based time-frequency analysis can be applied to natural physical signals such as earthquake waves, winds, ocean acoustic signals, mechanical diagnosis signals, and biomedical signals. In previous studies, we examined Hilbert-Huang transformation-based time-frequency analysis of the electroencephalogram FPI signals of clinical alcoholics, and 'sharp I' wave-based Hilbert-Huang transformation time-frequency features. In this paper, we discuss the application of Hilbert-Huang transformation-based time-frequency analysis to biomedical signals, such as electroencephalogram, electrocardiogram signals, electrogastrogram recordings, and speech signals. PMID:22558835

  5. Application of time-frequency methods to sound-quality analysis in automobiles

    NASA Astrophysics Data System (ADS)

    French, Mark; Cohen, Leon; Loughlin, Patrick J.

    1999-11-01

    We apply time-frequency methods to automotive vibration signals for sound quality analysis. Our analysis indicates that time-frequency methods provide additional information beyond that provided by the spectral density and vibration time series that is relevant to the assessment of noise and sound quality.

  6. GABOR FRAMES AND DIRECTIONAL TIME-FREQUENCY LOUKAS GRAFAKOS AND CHRISTOPHER SANSING

    E-print Network

    Grafakos, Loukas

    an approach based on time-frequency or Gabor elements. For such elements, a Parse- val formula and a continous topics of time-frequency analysis with the additional element of direction. A fundamental tool in time. To achieve this, we utilize the directionally-sensitive Radon transform defined for functions f in 1991

  7. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images

    PubMed Central

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N.; Zangwill, Linda M.

    2014-01-01

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the “non-progressing” and “progressing” glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection. PMID:25606299

  8. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images

    NASA Astrophysics Data System (ADS)

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N.; Zangwill, Linda M.

    2014-03-01

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the "non-progressing" and "progressing" glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection.

  9. Data-domain correlation approach for joint hydrogeologic inversion of time-lapse hydrogeologic and geophysical data

    SciTech Connect

    Timothy C. Johnson; Roelof J. Versteeg; Hai Huang; Partha S. Routh

    2009-11-01

    Inverse estimations of hydrogeologic properties are often highly uncertain due to the expense of collecting hydrogeologic data and the subsequent lack of information. Geophysical data can potentially help fill this information gap because geophysical methods can survey large areas remotely and relatively inexpensively. However, geophysical data are difficult to incorporate into hydrogeological parameter estimations due primarily to a lack of knowledge concerning the petrophysical relationships between hydrogeological and geophysical parameters. We present a method which allows time lapse geophysical data to be directly incorporated into a hydrogeological parameter estimation when there is a strong correlation between changes in geophysical and hydrogeological properties. This approach bypasses the need for an explicit petrophysical transform by formulating the geophysical part of the hydrogeological inversion in terms of a data domain correlation operator. We demonstrate the approach with a synthetic electrical resistivity monitoring application used to estimate the hydraulic conductivity distribution. Including time lapse resistivity data to supplement sparse hydrological data appears to greatly improve resolution of hydraulic conductivity in this case. More generally, the formulation and results suggest that geophysical monitoring data can be effectively incorporated into a hydrogeological parameter estimation using a data domain correlation operator, assuming there is a strong correlation between changes in hydrogeological and geophysical properties.

  10. Instantaneous quantities and uncertainty concepts for signal-dependent time-frequency distributions

    NASA Astrophysics Data System (ADS)

    Jones, Graeme; Boashash, Boualem

    1991-12-01

    This paper presents a review of some concepts associated with time-frequency distributions-- the instantaneous frequency, group delay, instantaneous bandwidth, and marginal properties-- and generalizes them in time-frequency via rotation of coordinates. This work emphasizes the need to examine time-frequency distributions in the general time-frequency plane, rather than restricting oneself to a time and/or frequency framework. This analysis leads to a generalized uncertainty principle, which has previously been introduced in radar theory. This uncertainty principle is invariant under rotation in the time-frequency plane, and should be used instead of the traditional definition of Gabor. It is desired to smooth a time-frequency distribution that is an energy density function into one that is an energy function. Most distributions are combinations of density and energy functions but the Wigner-Ville distribution is purely a density function. By using a local version of the generalized uncertainty principle, the Wigner- Ville distribution is smoothed into a signal dependent spectrogram using an iterative algorithm. It is believed that this procedure may represent, in some way an optimum removal of signal uncertainty in the time-frequency plane.

  11. Performance comparison of ISAR imaging method based on time frequency transforms

    NASA Astrophysics Data System (ADS)

    Xie, Chunjian; Guo, Chenjiang; Xu, Jiadong

    2013-03-01

    Inverse synthetic aperture radar (ISAR) can image the moving target, especially the target in the air, so it is important in the air defence and missile defence system. Time-frequency Transform was applied to ISAR imaging process widely. Several time frequency transforms were introduced. Noise jamming methods were analysed, and when these noise jamming were added to the echo of the ISAR receiver, the image can become blur even can't to be identify. But the effect is different to the different time frequency analysis. The results of simulation experiment show the Performance Comparison of the method.

  12. Detection of epileptiform activity in EEG signals based on time-frequency and non-linear analysis

    PubMed Central

    Gajic, Dragoljub; Djurovic, Zeljko; Gligorijevic, Jovan; Di Gennaro, Stefano; Savic-Gajic, Ivana

    2015-01-01

    We present a new technique for detection of epileptiform activity in EEG signals. After preprocessing of EEG signals we extract representative features in time, frequency and time-frequency domain as well as using non-linear analysis. The features are extracted in a few frequency sub-bands of clinical interest since these sub-bands showed much better discriminatory characteristics compared with the whole frequency band. Then we optimally reduce the dimension of feature space to two using scatter matrices. A decision about the presence of epileptiform activity in EEG signals is made by quadratic classifiers designed in the reduced two-dimensional feature space. The accuracy of the technique was tested on three sets of electroencephalographic (EEG) signals recorded at the University Hospital Bonn: surface EEG signals from healthy volunteers, intracranial EEG signals from the epilepsy patients during the seizure free interval from within the seizure focus and intracranial EEG signals of epileptic seizures also from within the seizure focus. An overall detection accuracy of 98.7% was achieved. PMID:25852534

  13. Time-Frequency Analysis of Beach Bacteria Variations and its Implication for Recreational Water Quality Modeling

    EPA Science Inventory

    This paper explores the potential of time-frequency wavelet analysis in resolving beach bacteria concentration and possible explanatory variables across multiple time scales with temporal information still preserved. The wavelet scalograms of E. coli concentrations and the explan...

  14. Time-frequency and advanced frequency estimation techniques for the investigation of bat echolocation calls.

    PubMed

    Kopsinis, Yannis; Aboutanios, Elias; Waters, Dean A; McLaughlin, Steve

    2010-02-01

    In this paper, techniques for time-frequency analysis and investigation of bat echolocation calls are studied. Particularly, enhanced resolution techniques are developed and/or used in this specific context for the first time. When compared to traditional time-frequency representation methods, the proposed techniques are more capable of showing previously unseen features in the structure of bat echolocation calls. It should be emphasized that although the study is focused on bat echolocation recordings, the results are more general and applicable to many other types of signal. PMID:20136233

  15. Joint swelling

    MedlinePLUS

    Swelling of a joint ... Joint swelling may occur along with joint pain . The swelling may cause the joint to appear larger or abnormally shaped. Joint swelling can cause pain or stiffness. After an ...

  16. Vibration Sensor Data Denoising Using a Time-Frequency Manifold for Machinery Fault Diagnosis

    PubMed Central

    He, Qingbo; Wang, Xiangxiang; Zhou, Qiang

    2014-01-01

    Vibration sensor data from a mechanical system are often associated with important measurement information useful for machinery fault diagnosis. However, in practice the existence of background noise makes it difficult to identify the fault signature from the sensing data. This paper introduces the time-frequency manifold (TFM) concept into sensor data denoising and proposes a novel denoising method for reliable machinery fault diagnosis. The TFM signature reflects the intrinsic time-frequency structure of a non-stationary signal. The proposed method intends to realize data denoising by synthesizing the TFM using time-frequency synthesis and phase space reconstruction (PSR) synthesis. Due to the merits of the TFM in noise suppression and resolution enhancement, the denoised signal would have satisfactory denoising effects, as well as inherent time-frequency structure keeping. Moreover, this paper presents a clustering-based statistical parameter to evaluate the proposed method, and also presents a new diagnostic approach, called frequency probability time series (FPTS) spectral analysis, to show its effectiveness in fault diagnosis. The proposed TFM-based data denoising method has been employed to deal with a set of vibration sensor data from defective bearings, and the results verify that for machinery fault diagnosis the method is superior to two traditional denoising methods. PMID:24379045

  17. Vibration sensor data denoising using a time-frequency manifold for machinery fault diagnosis.

    PubMed

    He, Qingbo; Wang, Xiangxiang; Zhou, Qiang

    2013-01-01

    Vibration sensor data from a mechanical system are often associated with important measurement information useful for machinery fault diagnosis. However, in practice the existence of background noise makes it difficult to identify the fault signature from the sensing data. This paper introduces the time-frequency manifold (TFM) concept into sensor data denoising and proposes a novel denoising method for reliable machinery fault diagnosis. The TFM signature reflects the intrinsic time-frequency structure of a non-stationary signal. The proposed method intends to realize data denoising by synthesizing the TFM using time-frequency synthesis and phase space reconstruction (PSR) synthesis. Due to the merits of the TFM in noise suppression and resolution enhancement, the denoised signal would have satisfactory denoising effects, as well as inherent time-frequency structure keeping. Moreover, this paper presents a clustering-based statistical parameter to evaluate the proposed method, and also presents a new diagnostic approach, called frequency probability time series (FPTS) spectral analysis, to show its effectiveness in fault diagnosis. The proposed TFM-based data denoising method has been employed to deal with a set of vibration sensor data from defective bearings, and the results verify that for machinery fault diagnosis the method is superior to two traditional denoising methods. PMID:24379045

  18. Dynamic Time-Frequency Waveforms for VSA Characterization of PA Long-term Memory Effects

    E-print Network

    Dynamic Time-Frequency Waveforms for VSA Characterization of PA Long-term Memory Effects Jie Hu1-tone amplitude and dynamic frequency characteristics for PA memory evaluation by using the Vector Signal Analyser to characterize the PA over frequency with a single measurement similar to what is done for a two-tone excitation

  19. Adaptive noise cancelling and time-frequency techniques for rail surface defect detection

    NASA Astrophysics Data System (ADS)

    Liang, B.; Iwnicki, S.; Ball, A.; Young, A. E.

    2015-03-01

    Adaptive noise cancelling (ANC) is a technique which is very effective to remove additive noises from the contaminated signals. It has been widely used in the fields of telecommunication, radar and sonar signal processing. However it was seldom used for the surveillance and diagnosis of mechanical systems before late of 1990s. As a promising technique it has gradually been exploited for the purpose of condition monitoring and fault diagnosis. Time-frequency analysis is another useful tool for condition monitoring and fault diagnosis purpose as time-frequency analysis can keep both time and frequency information simultaneously. This paper presents an ANC and time-frequency application for railway wheel flat and rail surface defect detection. The experimental results from a scaled roller test rig show that this approach can significantly reduce unwanted interferences and extract the weak signals from strong background noises. The combination of ANC and time-frequency analysis may provide us one of useful tools for condition monitoring and fault diagnosis of railway vehicles.

  20. A TIME-FREQUENCY APPROACH TO BLIND DECONVOLUTION IN MULTIPATH UNDERWATER CHANNELS

    E-print Network

    Jesus, Sérgio M.

    matched-filter. Si- mulations used a ray-tracing physical model, initiated with at-sea recordedA TIME-FREQUENCY APPROACH TO BLIND DECONVOLUTION IN MULTIPATH UNDERWATER CHANNELS N. Martins, S@ensieta.fr, quinquis@ensieta.fr ABSTRACT Blind deconvolution is presented in the underwater acoustic channel context

  1. Evaluation of the importance of time-frequency contributions to speech intelligibility in noise

    E-print Network

    Johnson, Michael T.

    Evaluation of the importance of time-frequency contributions to speech intelligibility in noise to speech intelligibility is highly related to the loudness of its target component, while the importance of each speech-absent T-F unit varies according to the loudness of its masker component. Two types of mask

  2. TIME-FREQUENCY SEGMENTATION OF BIRD SONG IN NOISY ACOUSTIC ENVIRONMENTS

    E-print Network

    Fern, Xiaoli Zhang

    TIME-FREQUENCY SEGMENTATION OF BIRD SONG IN NOISY ACOUSTIC ENVIRONMENTS Lawrence Neal, Forrest-5501 ABSTRACT Recent work in machine learning considers the problem of identifying bird species from an audio recording. Most meth- ods require segmentation to isolate each syllable of bird call in input audio. Energy

  3. Analysis of Cardio-respiratory Dynamics during Mental Stress using (Partial) Time-Frequency Spectra

    E-print Network

    to conduct a combined analysis of the cardio-respiratory system. In this study, we will perform cross timeAnalysis of Cardio-respiratory Dynamics during Mental Stress using (Partial) Time-Frequency Spectra Engineering, ESAT - STADIUS Center for Dynamical Systems, Signal Processing and Data Analytics, KU Leuven

  4. Inverse synthetic aperture radar processing using parametric time-frequency estimators Phase I

    SciTech Connect

    Candy, J.V., LLNL

    1997-12-31

    This report summarizes the work performed for the Office of the Chief of Naval Research (ONR) during the period of 1 September 1997 through 31 December 1997. The primary objective of this research was aimed at developing an alternative time-frequency approach which is recursive-in-time to be applied to the Inverse Synthethic Aperture Radar (ISAR) imaging problem discussed subsequently. Our short term (Phase I) goals were to: 1. Develop an ISAR stepped-frequency waveform (SFWF) radar simulator based on a point scatterer vehicular target model incorporating both translational and rotational motion; 2. Develop a parametric, recursive-in-time approach to the ISAR target imaging problem; 3. Apply the standard time-frequency short-term Fourier transform (STFT) estimator, initially to a synthesized data set; and 4. Initiate the development of the recursive algorithm. We have achieved all of these goals during the Phase I of the project and plan to complete the overall development, application and comparison of the parametric approach to other time-frequency estimators (STFT, etc.) on our synthesized vehicular data sets during the next phase of funding. It should also be noted that we developed a batch minimum variance translational motion compensation (TMC) algorithm to estimate the radial components of target motion (see Section IV). This algorithm is easily extended to recursive solution and will probably become part of the overall recursive processing approach to solve the ISAR imaging problem. Our goals for the continued effort are to: 1. Develop and extend a complex, recursive-in-time, time- frequency parameter estimator based on the recursive prediction error method (RPEM) using the underlying Gauss- Newton algorithms. 2. Apply the complex RPEM algorithm to synthesized ISAR data using the above simulator. 3. Compare the performance of the proposed algorithm to standard time-frequency estimators applied to the same data sets.

  5. Quadratic Time-Frequency Analysis of Hydroacoustic Signals as Applied to Acoustic Emissions of Large Whales

    NASA Astrophysics Data System (ADS)

    Le Bras, Ronan; Victor, Sucic; Damir, Malnar; Götz, Bokelmann

    2014-05-01

    In order to enrich the set of attributes in setting up a large database of whale signals, as envisioned in the Baleakanta project, we investigate methods of time-frequency analysis. The purpose of establishing the database is to increase and refine knowledge of the emitted signal and of its propagation characteristics, leading to a better understanding of the animal migrations in a non-invasive manner and to characterize acoustic propagation in oceanic media. The higher resolution for signal extraction and a better separation from other signals and noise will be used for various purposes, including improved signal detection and individual animal identification. The quadratic class of time-frequency distributions (TFDs) is the most popular set of time-frequency tools for analysis and processing of non-stationary signals. Two best known and most studied members of this class are the spectrogram and the Wigner-Ville distribution. However, to be used efficiently, i.e. to have highly concentrated signal components while significantly suppressing interference and noise simultaneously, TFDs need to be optimized first. The optimization method used in this paper is based on the Cross-Wigner-Ville distribution, and unlike similar approaches it does not require prior information on the analysed signal. The method is applied to whale signals, which, just like the majority of other real-life signals, can generally be classified as multicomponent non-stationary signals, and hence time-frequency techniques are a natural choice for their representation, analysis, and processing. We present processed data from a set containing hundreds of individual calls. The TFD optimization method results into a high resolution time-frequency representation of the signals. It allows for a simple extraction of signal components from the TFD's dominant ridges. The local peaks of those ridges can then be used for the signal components instantaneous frequency estimation, which in turn can be used as one of the features in any subsequent classification of the whale signals.

  6. Time-frequency analysis for microwave reflectometry data processing in the HL-2A tokamak

    NASA Astrophysics Data System (ADS)

    Zhong, W. L.; Shi, Z. B.; Zou, X. L.; Ding, X. T.; Huang, X. L.; Dong, Y. B.; Liu, Z. T.; Xiao, W. W.; Ji, X. Q.; Cui, Z. Y.; Liu, Yi; Yan, L. W.; Yang, Q. W.; Duan, X. R.

    2011-10-01

    The Choi-Williams distribution (CWD) technique is introduced as a time-frequency tool for processing data measured from the new developed homodyne and the fixed frequency reflectometry in the HL-2A tokamak. The comparison between spectrogram and CWD for the simulated signal is presented. It indicates that the CWD can greatly improve the representation of the time-frequency content of the multi-components signal. Its effectiveness is demonstrated through two applications in HL-2A, which are the extraction of beat frequencies from the frequency modulated-continuous wave reflectometry (FM-CW) and the characterizing of the fluctuations. The density profile inversed from the group delay of the FM-CW and the density fluctuations deduced from the fixed-frequency reflectometry would be more reliable and accurate by using the CWD technique.

  7. Considering the influence of artificial environmental noise to study cough time-frequency features

    NASA Astrophysics Data System (ADS)

    Van Hirtum, A.; Berckmans, D.

    2003-09-01

    In general the study of the cough mechanism and sound in both animal and human is performed by eliciting coughing in a reproducible way by nebulization of an irritating substance. Due to ventilation the controlled evaporation-protocol causes artificial noises from a mechanical origin. The resulting environmental low-frequency noises complicate cough time-frequency features. In order to optimize the study of the cough-sound the research described in this paper attempts on the one hand to characterize and model the environmental noises and on the other hand to evaluate the influence of the noise on the time-frequency representation for the intended cough sounds by comparing different de-noising approaches. Free field acoustic sound is continuously registered during 30 min citric acid cough-challenges on individual Belgian Landrace piglets and during respiratory infection experiments, with a duration of about 10 days, where room-ventilation was present.

  8. Kolmogorov-Smirnov like test for time-frequency Fourier spectrogram analysis in LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Ferraioli, Luigi; Armano, Michele; Audley, Heather; Congedo, Giuseppe; Diepholz, Ingo; Gibert, Ferran; Hewitson, Martin; Hueller, Mauro; Karnesis, Nikolaos; Korsakova, Natalia; Nofrarias, Miquel; Plagnol, Eric; Vitale, Stefano

    2015-03-01

    A statistical procedure for the analysis of time-frequency noise maps is presented and applied to LISA Pathfinder mission synthetic data. The procedure is based on the Kolmogorov-Smirnov like test that is applied to the analysis of time-frequency noise maps produced with the spectrogram technique. The influence of the finite size windowing on the statistic of the test is calculated with a Monte Carlo simulation for 4 different windows type. Such calculation demonstrate that the test statistic is modified by the correlations introduced in the spectrum by the finite size of the window and by the correlations between different time bins originated by overlapping between windowed segments. The application of the test procedure to LISA Pathfinder data demonstrates the test capability of detecting non-stationary features in a noise time series that is simulating low frequency non-stationary noise in the system.

  9. Aurally-adequate time-frequency analysis for scattered sound in auditoria

    NASA Astrophysics Data System (ADS)

    Norris, Molly K.; Xiang, Ning; Kleiner, Mendel

    2005-04-01

    The goal of this work was to apply an aurally-adequate time-frequency analysis technique to the analysis of sound scattering effects in auditoria. Time-frequency representations were developed as a motivated effort that takes into account binaural hearing, with a specific implementation of interaural cross-correlation process. A model of the human auditory system was implemented in the MATLAB platform based on two previous models [A. Härmä and K. Palomäki, HUTear, Espoo, Finland; and M. A. Akeroyd, A. Binaural Cross-correlogram Toolbox for MATLAB (2001), University of Sussex, Brighton]. These stages include proper frequency selectivity, the conversion of the mechanical motion of the basilar membrane to neural impulses, and binaural hearing effects. The model was then used in the analysis of room impulse responses with varying scattering characteristics. This paper discusses the analysis results using simulated and measured room impulse responses. [Work supported by the Frank H. and Eva B. Buck Foundation.

  10. Hypermobile joints

    MedlinePLUS

    ... hypermobile joints have an increased risk for joint dislocation and other problems. Extra care may be needed ... the joint? Is there any history of joint dislocation, difficulty walking, or difficulty using the arms? Further ...

  11. Transient analysis with fast Wilson-Daubechies time-frequency transform

    NASA Astrophysics Data System (ADS)

    Necula, V.; Klimenko, S.; Mitselmakher, G.

    2012-06-01

    The time-frequency transforms are important tools for identification of transient events in the output of the gravitational-wave detectors. Produced by the terrestrial and possibly by astrophysical sources, the transient events can be identified as patterns on the time-frequency plane with the excess power above stationary detector noise. In this paper we consider a particular case of the Wilson-Daubechies time-frequency transform for use in the gravitational-wave burst analysis. The presented Wilson-Daubechies basis shares some properties with the Gabor frames, but circumvents the Balian-Low theorem. It also shares similarity with the Meyer wavelet, which is actively used in the gravitational-wave burst analysis. The main advantages of the Wilson-Daubechies transform are the low computational cost, spectral leakage control, flexible structure of the frequency sub-bands, and the existence of the analytic time-delay filters, which are important for localization of the gravitational-wave sources in the sky. These properties of the Wilson-Daubechies transform may prove useful not only in the transient analysis, but also in other areas of the gravitational wave data analysis and detector characterization.

  12. Using time-frequency analysis to determine time-resolved detonation velocity with microwave interferometry

    NASA Astrophysics Data System (ADS)

    Kittell, David E.; Mares, Jesus O.; Son, Steven F.

    2015-04-01

    Two time-frequency analysis methods based on the short-time Fourier transform (STFT) and continuous wavelet transform (CWT) were used to determine time-resolved detonation velocities with microwave interferometry (MI). The results were directly compared to well-established analysis techniques consisting of a peak-picking routine as well as a phase unwrapping method (i.e., quadrature analysis). The comparison is conducted on experimental data consisting of transient detonation phenomena observed in triaminotrinitrobenzene and ammonium nitrate-urea explosives, representing high and low quality MI signals, respectively. Time-frequency analysis proved much more capable of extracting useful and highly resolved velocity information from low quality signals than the phase unwrapping and peak-picking methods. Additionally, control of the time-frequency methods is mainly constrained to a single parameter which allows for a highly unbiased analysis method to extract velocity information. In contrast, the phase unwrapping technique introduces user based variability while the peak-picking technique does not achieve a highly resolved velocity result. Both STFT and CWT methods are proposed as improved additions to the analysis methods applied to MI detonation experiments, and may be useful in similar applications.

  13. Signal analysis by means of time-frequency (Wigner-type) distributions -- Applications to sonar and radar echoes

    SciTech Connect

    Gaunaurd, G.; Strifors, H.C.

    1996-09-01

    Time series data have been traditionally analyzed in either the time or the frequency domains. For signals with a time-varying frequency content, the combined time-frequency (TF) representations, based on the Cohen class of (generalized) Wigner distributions (WD`s) offer a powerful analysis tool. Using them, it is possible to: (1) trace the time-evolution of the resonance features usually present in a standard sonar cross section (SCS), or in a radar cross section (RCS) and (2) extract target information that may be difficult to even notice in an ordinary SCS or RCS. After a brief review of the fundamental properties of the WD, the authors discuss ways to reduce or suppress the cross term interference that appears in the WD of multicomponent systems. These points are illustrated with a variety of three-dimensional (3-D) plots of Wigner and pseudo-Wigner distributions (PWD), in which the strength of the distribution is depicted as the height of a Wigner surface with height scales measured by various color shades or pseudocolors. The authors also review studies they have made of the echoes returned by conducting or dielectric targets in the atmosphere, when they are illuminated by broadband radar pings. A TF domain analysis of these impulse radar returns demonstrates their superior informative content. These plots allow the identification of targets in an easier and clearer fashion than by the conventional RCS of narrowband systems. The authors show computed and measured plots of WD and PWD of various types of aircraft to illustrate the classification advantages of the approach at any aspect angle. They also show analogous results for metallic objects buried underground, in dielectric media, at various depths.

  14. Design and Modeling of Novel Multiband/Wideband Antennas for RFID Tags and Readers Using Time-/Frequency-Domain Simulators

    E-print Network

    Tentzeris, Manos

    have low cost, low profile and especially small size. The RFID tags also present challengesDesign and Modeling of Novel Multiband/Wideband Antennas for RFID Tags and Readers Using Time Radio Frequency Identification (RFID) tags and readers is presented. Ultra-low-cost organic substrates

  15. Application of Wigner's time-frequency distribution for close signal recognition

    NASA Astrophysics Data System (ADS)

    Vodovatov, Igor A.; Visotzki, Micael G.; Rogov, Sergei A.; Tkachenko, Andrei G.

    2003-06-01

    In the up-to-date optical processing of information the special attention is paid to the procession of non-stationary signals. Time-frequency distribution are widely applied for analysis of such signals lately. The possibility of using cross-Wigner's distribution (CWD) was used theoretically. The experiment verification of the possibility of the affined signal recognition by the moments method was carried out taking into account that the CWD section corresponding to ? = ?0 in case of the symmetrical envelope of the reference signal coincides with the cross-correlation function.

  16. Time-frequency representation of a highly nonstationary signal via the modified Wigner distribution

    NASA Technical Reports Server (NTRS)

    Zoladz, T. F.; Jones, J. H.; Jong, J.

    1992-01-01

    A new signal analysis technique called the modified Wigner distribution (MWD) is presented. The new signal processing tool has been very successful in determining time frequency representations of highly non-stationary multicomponent signals in both simulations and trials involving actual Space Shuttle Main Engine (SSME) high frequency data. The MWD departs from the classic Wigner distribution (WD) in that it effectively eliminates the cross coupling among positive frequency components in a multiple component signal. This attribute of the MWD, which prevents the generation of 'phantom' spectral peaks, will undoubtedly increase the utility of the WD for real world signal analysis applications which more often than not involve multicomponent signals.

  17. Applications of time-frequency analysis to signals from manufacturing and machine monitoring sensors

    SciTech Connect

    Atlas, L.E.; Narayanan, S.B.; Bernard, G.D.

    1996-09-01

    Manufacturing industries are now demanding substantial increases in flexibility, productivity and reliability from their process machines as well as increased quality and value of their products. One important strategy to support this goal is sensor-based, on-line, real-time evaluation of key characteristics of both machines and products, throughout the manufacturing process. Recent advances in time-frequency (TF) analysis are particularly well suited to extracting key vibrational characteristics from monitoring sensors. Thus this paper presents applications of TF analysis to several important manufacturing and machine monitoring tasks, to show the value of these forms of digital signal processing applied to manufacturing.

  18. Time-frequency analysis of Transitory/Permanent frequency decrease in civil engineering structures during earthquakes

    E-print Network

    Michel, Clotaire

    2008-01-01

    The analysis of strong motion recordings in structures is crucial to understand the damaging process during earthquakes. A very precise time-frequency representation, the reassigned smoothed pseudo-Wigner-Ville method, allowed us to follow the variation of the Millikan Library (California) and the Grenoble City Hall building (France) resonance frequencies during earthquakes. Under strong motions, a quick frequency drop, attributed to damage of the soil-structure system, followed by a slower increase is found. However, in the case of weak earthquakes, we show that frequency variations come from the ground motion spectrum and cannot be interpreted in terms of change of the soil-structure system.

  19. Improved time-frequency analysis of extreme-mass-ratio inspiral signals in mock LISA data

    E-print Network

    Gair, Jonathan R; Wen, Linqing

    2008-01-01

    The planned Laser Interferometer Space Antenna (LISA) is expected to detect gravitational wave signals from ~100 extreme-mass-ratio inspirals (EMRIs) of stellar-mass compact objects into massive black holes. The long duration and large parameter space of EMRI signals makes data analysis for these signals a challenging problem. One approach to EMRI data analysis is to use time-frequency methods. This consists of two steps: (i) searching for tracks from EMRI sources in a time-frequency spectrogram, and (ii) extracting parameter estimates from the tracks. In this paper we discuss the results of applying these techniques to the latest round of the Mock LISA Data Challenge, Round 1B. This analysis included three new techniques not used in previous analyses: (i) a new Chirp-based Algorithm for Track Search for track detection; (ii) estimation of the inclination of the source to the line of sight; (iii) a Metropolis-Hastings Monte Carlo over the parameter space in order to find the best fit to the tracks.

  20. Noise resistant time frequency analysis and application in fault diagnosis of rolling element bearings

    NASA Astrophysics Data System (ADS)

    Dong, Guangming; Chen, Jin

    2012-11-01

    Rolling element bearings are frequently used in rotary machinery, but they are also fragile mechanical parts. Hence, exact condition monitoring and fault diagnosis for them plays an important role in ensuring machinery's reliable running. Timely diagnosis of early bearing faults is desirable, but the early fault signatures are easily submerged in noise. In this paper, Wigner-Ville spectrum based on cyclic spectral density (CSWVS for a brief notation) is studied, which is able to represent the cyclostationary signals while reducing the masking effect of additive stationary noise. Both simulations and experiments show that CSWVS is a noise resistant time frequency analysis technique for extracting bearing fault patterns, when bearing signals are under influences of random noise and gear vibrations. The 3-D feature of the CSWVS is proved useful in extracting bearing fault pattern from gearbox vibration signals, where bearing signals are affected by gear meshing vibration and noise. Besides, CSWVS utilizes the second order cyclostationary property of the vibration signals produced by bearing distributed fault, and clearly extracts its fault features, which cannot be extracted by envelope analysis. To quantitatively describe the extent of bearing fault, Renyi information encoded in the time frequency diagram of CSWVS is studied. It is shown to be a more sensitive index to reflect bearing performance degradation, compared with the spectral entropy (SE), squared envelope spectrum entropy (SESE) and Renyi informations for WVD, PWVD, especially when SNR is low.

  1. Models of the Joint Structure of Domain-Related and Global Distress: Implications for the Reconciliation of Quality of Life and Mental Health Perspectives

    ERIC Educational Resources Information Center

    Magee, William; St-Arnaud, Sebastien

    2012-01-01

    Research on subjective wellbeing includes studies of both domain-related and global distress. The mental health literature, though, focuses almost exclusively on global distress. This seems to be partly due to a common belief that psychological distress, and the moods that comprise distress, necessarily lack referential content. However, if that…

  2. Time-frequency characterization of lamb waves for material evaluation and damage inspection of plates

    NASA Astrophysics Data System (ADS)

    Frank Pai, P.; Deng, Haoguang; Sundaresan, Mannur J.

    2015-10-01

    Guided wave-based technique is one major approach for damage inspection of structures. To detect a small damage, an elastic wave's wavelength needs to be in the order of the damage size and hence the frequency needs to be high. Unfortunately, high-frequency wave dynamics always involves complicated wave reflection, refraction and diffraction, and it is difficult to separate them in order to perform detailed examination and system identification. This paper investigates dynamic characteristics of Lamb waves in plates in order to be used for material evaluation and damage inspection of thin-walled structures. A one-dimensional finite-element modeling and analysis technique is developed for computing dispersion curves and all symmetric and antisymmetric modes of Lamb waves in isotropic and multi-layer plates. Moreover, the conjugate-pair decomposition (CPD) method is introduced for time-frequency analysis of propagating Lamb waves. Results show that, under a k-cycle sine-burst excitation at a plate's edge, the time-varying frequency of a surface point's response can reveal the Lamb wave propagating inside the plate being a symmetric or an antisymmetric mode. The frequency of the measured wave packet increases from the wave front to the trailing edge if it is a symmetric mode, and the frequency decreases from the wave front to the trailing edge if it is an antisymmetric mode. Moreover, interaction of two different wave packets results in a peak in the time-frequency curve. These characteristics can be used for accurate separation of wave packets and identification of different wave speeds to enable fast and accurate material evaluation and damage inspection. Transient finite-element analysis of Lamb waves in finite plates with crack/delamination show that k-cycle sine-burst probing waves are good agents for guided wave-based damage inspection of structures. Although crack and delamination introduce different waves into and complicate the probing wave packet, time-frequency analysis makes it possible to separate such damage-induced small waves from the probing wave and enable fast and accurate damage inspection of thin-walled structures.

  3. Looking for activity cycles in late-type Kepler stars using time-frequency analysis

    NASA Astrophysics Data System (ADS)

    Vida, K.; Oláh, K.; Szabó, R.

    2014-07-01

    We analyse light curves covering four years of 39 fast-rotating (Prot ? 1 d) late-type active stars from the Kepler data base. Using time-frequency analysis (short-term Fourier transform), we find hints for activity cycles of 300-900 d at nine targets from the changing typical latitude of the starspots, which with the differential rotation of the stellar surface change the observed rotation period over the activity cycle. We also give a lowest estimation for the shear parameter of the differential rotation, which is ?0.001 for the cycling targets. These results populate the less studied, short-period end of the rotation-cycle length relation.

  4. Dynamic response and time-frequency analysis for gear tooth crack detection

    NASA Astrophysics Data System (ADS)

    Mohammed, Omar D.; Rantatalo, Matti

    2016-01-01

    Vibration health monitoring is a non-destructive technique which can be applied to detect cracks propagating in gear teeth. This paper studies gear tooth crack detection by investigating the natural frequencies and by performing time-frequency analysis of a 6 DOF dynamic gear model. The gear mesh stiffness used in the model was calculated analytically for different cases of crack sizes. The frequency response functions (FRFs) of the model were derived for healthy and faulty cases and dynamic simulation was performed to obtain the time signal responses. A new approach involving a short-time Fourier transform (STFT) was applied where a fast Fourier transform (FFT) was calculated for successive blocks with different sizes corresponding to the time segments of the varying gear mesh stiffness. The relationship between the different crack sizes and the mesh-stiffness-dependent eigenfrequencies was studied in order to detect the tooth crack and to estimate its size.

  5. Optical Time-Frequency Packing: Principles, Design, Implementation, and Experimental Demonstration

    E-print Network

    Secondini, Marco; Fresi, Francesco; Meloni, Gianluca; Cavaliere, Fabio; Colavolpe, Giulio; Forestieri, Enrico; Potì, Luca; Sabella, Roberto; Prati, Giancarlo

    2014-01-01

    Time-frequency packing (TFP) transmission provides the highest achievable spectral efficiency with a constrained modulation format and detector complexity. In this work, the application of the TFP technique to fiber-optic systems is investigated and experimentally demonstrated. The main theoretical aspects, design guidelines, and implementation issues are discussed, focusing on those aspects which are peculiar to TFP systems. In particular, adaptive compensation of propagation impairments, matched filtering, and maximum a posteriori probability detection are obtained by a combination of a butterfly equalizer and four low-complexity parallel Bahl-Cocke-Jelinek-Raviv (BCJR) detectors. A novel algorithm that ensures adaptive equalization, channel estimation, and a proper distribution of tasks between the equalizer and BCJR detectors is proposed. A set of irregular low-density parity-check codes with different rates is designed to operate at low error rates and approach the spectral efficiency limit achievable by...

  6. Time-frequency processing of track irregularities in high-speed train

    NASA Astrophysics Data System (ADS)

    Ning, Jing; Lin, Jianhui; Zhang, Bing

    2016-01-01

    Track irregularities are the main source of vehicle vibration. With the increase in the speed, the track irregularities have become a more significant issue of concerned. The axle box acceleration signals can be obtained for analyzing the track irregularities, but the signals are usually non-stationary and signal processing results are not normally satisfied with the ordinary way. Thus, time-frequency distribution analysis is proposed to use in this study. To minimize the cross-terms, a new method based on Empirical Mode Decomposition (EMD) and Cohen's class distribution has been developed and advanced. This approach has been tested with three typical simulation signals and then applied to analyze the track irregularities. The result is consistent with the result from track inspection cars. This indicates this new algorithm is suitable for analyzing the track irregularities. It can be applied in rail irregularity measurement to compensate some shortages of the track inspection cars.

  7. Flutter of High-Speed Civil Transport Flexible Semispan Model: Time-Frequency Analysis

    NASA Technical Reports Server (NTRS)

    Chabalko, Christopher C.; Hajj, Muhammad R.; Silva, Walter A.

    2006-01-01

    Time/frequency analysis of fluctuations measured by pressure taps and strain gauges in the experimental studies of the flexible semispan model of a high-speed civil transport wing configuration is performed. The interest is in determining the coupling between the aerodynamic loads and structural motions that led to the hard flutter conditions and loss of the model. The results show that, away from the hard flutter point, the aerodynamic loads at all pressure taps near the wing tip and the structural motions contained the same frequency components. On the other hand, in the flow conditions leading to the hard flutter, the frequency content of the pressure fluctuations near the leading and trailing edges varied significantly. This led to contribution to the structural motions over two frequency ranges. The ratio of these ranges was near 2:1, which suggests the possibility of nonlinear structural coupling.

  8. Improving resolution of crosswell seismic section based on time-frequency analysis

    SciTech Connect

    Luo, H.; Li, Y.

    1994-12-31

    According to signal theory, to improve resolution of seismic section is to extend high-frequency band of seismic signal. In cross-well section, sonic log can be regarded as a reliable source providing high-frequency information to the trace near the borehole. In such case, what to do is to introduce this high-frequency information into the whole section. However, neither traditional deconvolution algorithms nor some new inversion methods such as BCI (Broad Constraint Inversion) are satisfied because of high-frequency noise and nonuniqueness of inversion results respectively. To overcome their disadvantages, this paper presents a new algorithm based on Time-Frequency Analysis (TFA) technology which has been increasingly received much attention as an useful signal analysis too. Practical applications show that the new method is a stable scheme to improve resolution of cross-well seismic section greatly without decreasing Signal to Noise Ratio (SNR).

  9. Recent advances in time-frequency analysis methods for machinery fault diagnosis: A review with application examples

    NASA Astrophysics Data System (ADS)

    Feng, Zhipeng; Liang, Ming; Chu, Fulei

    2013-07-01

    Nonstationary signal analysis is one of the main topics in the field of machinery fault diagnosis. Time-frequency analysis can identify the signal frequency components, reveals their time variant features, and is an effective tool to extract machinery health information contained in nonstationary signals. Various time-frequency analysis methods have been proposed and applied to machinery fault diagnosis. These include linear and bilinear time-frequency representations (e.g., wavelet transform, Cohen and affine class distributions), adaptive parametric time-frequency analysis (based on atomic decomposition and time-frequency auto-regressive moving average models), adaptive non-parametric time-frequency analysis (e.g., Hilbert-Huang transform, local mean decomposition, and energy separation), and time varying higher order spectra. This paper presents a systematic review of over 20 major such methods reported in more than 100 representative articles published since 1990. Their fundamental principles, advantages and disadvantages, and applications to fault diagnosis of machinery have been examined. Some examples have also been provided to illustrate their performance.

  10. Time-frequency analysis of band-limited EEG with BMFLC and Kalman filter for BCI applications

    PubMed Central

    2013-01-01

    Background Time-Frequency analysis of electroencephalogram (EEG) during different mental tasks received significant attention. As EEG is non-stationary, time-frequency analysis is essential to analyze brain states during different mental tasks. Further, the time-frequency information of EEG signal can be used as a feature for classification in brain-computer interface (BCI) applications. Methods To accurately model the EEG, band-limited multiple Fourier linear combiner (BMFLC), a linear combination of truncated multiple Fourier series models is employed. A state-space model for BMFLC in combination with Kalman filter/smoother is developed to obtain accurate adaptive estimation. By virtue of construction, BMFLC with Kalman filter/smoother provides accurate time-frequency decomposition of the bandlimited signal. Results The proposed method is computationally fast and is suitable for real-time BCI applications. To evaluate the proposed algorithm, a comparison with short-time Fourier transform (STFT) and continuous wavelet transform (CWT) for both synthesized and real EEG data is performed in this paper. The proposed method is applied to BCI Competition data IV for ERD detection in comparison with existing methods. Conclusions Results show that the proposed algorithm can provide optimal time-frequency resolution as compared to STFT and CWT. For ERD detection, BMFLC-KF outperforms STFT and BMFLC-KS in real-time applicability with low computational requirement. PMID:24274109

  11. Effects of mobile phone exposure on time frequency fine structure of transiently evoked otoacoustic emissions.

    PubMed

    Paglialonga, Alessia; Tognola, Gabriella; Parazzini, Marta; Lutman, Mark E; Bell, Steven L; Thuroczy, Gyorgy; Ravazzani, Paolo

    2007-10-01

    Mobile phones have become very commonly used worldwide within a short period of time. To date there is only limited knowledge about interaction between electromagnetic fields (EMFs) emitted by mobile phones and the auditory function. Moreover, there is widespread concern that there may be potential for harm. The aim of this study was to assess potential subtle changes in cochlear function by measuring the temporal and spectral fine structure of transiently evoked otoacoustic emissions (TEOAE) in normal hearing subjects after exposure to EMFs emitted by Global System for Mobile Communication (GSM) mobile phones. TEOAEs were recorded in 27 healthy young adults before and after 10 min of real or sham exposure in a double-blind design. TEOAE data were analyzed both globally (broadband analysis) and using the Wavelet Transform (analysis of the time-frequency fine structure). The broadband analysis revealed no significant effect on TEOAEs related to exposure, confirming results of previous studies; in addition, no significant change was detected in the analysis of the elementary wavelet components, suggesting that the temporal and spectral fine structure of TEOAEs is not affected by 10 min exposure to low-intensity EMFs emitted by GSM mobile phones. PMID:17902853

  12. Time-Frequency Analysis of Rocket Nozzle Wall Pressures During Start-up Transients

    NASA Technical Reports Server (NTRS)

    Baars, Woutijn J.; Tinney, Charles E.; Ruf, Joseph H.

    2011-01-01

    Surveys of the fluctuating wall pressure were conducted on a sub-scale, thrust- optimized parabolic nozzle in order to develop a physical intuition for its Fourier-azimuthal mode behavior during fixed and transient start-up conditions. These unsteady signatures are driven by shock wave turbulent boundary layer interactions which depend on the nozzle pressure ratio and nozzle geometry. The focus however, is on the degree of similarity between the spectral footprints of these modes obtained from transient start-ups as opposed to a sequence of fixed nozzle pressure ratio conditions. For the latter, statistically converged spectra are computed using conventional Fourier analyses techniques, whereas the former are investigated by way of time-frequency analysis. The findings suggest that at low nozzle pressure ratios -- where the flow resides in a Free Shock Separation state -- strong spectral similarities occur between fixed and transient conditions. Conversely, at higher nozzle pressure ratios -- where the flow resides in Restricted Shock Separation -- stark differences are observed between the fixed and transient conditions and depends greatly on the ramping rate of the transient period. And so, it appears that an understanding of the dynamics during transient start-up conditions cannot be furnished by a way of fixed flow analysis.

  13. Damage detection and quantification in a structural model under seismic excitation using time-frequency analysis

    NASA Astrophysics Data System (ADS)

    Chan, Chun-Kai; Loh, Chin-Hsiung; Wu, Tzu-Hsiu

    2015-04-01

    In civil engineering, health monitoring and damage detection are typically carry out by using a large amount of sensors. Typically, most methods require global measurements to extract the properties of the structure. However, some sensors, like LVDT, cannot be used due to in situ limitation so that the global deformation remains unknown. An experiment is used to demonstrate the proposed algorithms: a one-story 2-bay reinforce concrete frame under weak and strong seismic excitation. In this paper signal processing techniques and nonlinear identification are used and applied to the response measurements of seismic response of reinforced concrete structures subject to different level of earthquake excitations. Both modal-based and signal-based system identification and feature extraction techniques are used to study the nonlinear inelastic response of RC frame using both input and output response data or output only measurement. From the signal-based damage identification method, which include the enhancement of time-frequency analysis of acceleration responses and the estimation of permanent deformation using directly from acceleration response data. Finally, local deformation measurement from dense optical tractor is also use to quantify the damage of the RC frame structure.

  14. Solving the EEG inverse problem based on space-time-frequency structured sparsity constraints.

    PubMed

    Castaño-Candamil, Sebastián; Höhne, Johannes; Martínez-Vargas, Juan-David; An, Xing-Wei; Castellanos-Domínguez, German; Haufe, Stefan

    2015-09-01

    We introduce STOUT (spatio-temporal unifying tomography), a novel method for the source analysis of electroencephalograpic (EEG) recordings, which is based on a physiologically-motivated source representation. Our method assumes that only a small number of brain sources are active throughout a measurement, where each of the sources exhibits focal (smooth but localized) characteristics in space, time and frequency. This structure is enforced through an expansion of the source current density into appropriate spatio-temporal basis functions in combination with sparsity constraints. This approach combines the main strengths of two existing methods, namely Sparse Basis Field Expansions (Haufe et al., 2011) and Time-Frequency Mixed-Norm Estimates (Gramfort et al., 2013). By adjusting the ratio between two regularization terms, STOUT is capable of trading temporal for spatial reconstruction accuracy and vice versa, depending on the requirements of specific analyses and the provided data. Due to allowing for non-stationary source activations, STOUT is particularly suited for the localization of event-related potentials (ERP) and other evoked brain activity. We demonstrate its performance on simulated ERP data for varying signal-to-noise ratios and numbers of active sources. Our analysis of the generators of visual and auditory evoked N200 potentials reveals that the most active sources originate in the temporal and occipital lobes, in line with the literature on sensory processing. PMID:26048621

  15. Evaluation of the importance of time-frequency contributions to speech intelligibility in noise.

    PubMed

    Yu, Chengzhu; Wójcicki, Kamil K; Loizou, Philipos C; Hansen, John H L; Johnson, Michael T

    2014-05-01

    Recent studies on binary masking techniques make the assumption that each time-frequency (T-F) unit contributes an equal amount to the overall intelligibility of speech. The present study demonstrated that the importance of each T-F unit to speech intelligibility varies in accordance with speech content. Specifically, T-F units are categorized into two classes, speech-present T-F units and speech-absent T-F units. Results indicate that the importance of each speech-present T-F unit to speech intelligibility is highly related to the loudness of its target component, while the importance of each speech-absent T-F unit varies according to the loudness of its masker component. Two types of mask errors are also considered, which include miss and false alarm errors. Consistent with previous work, false alarm errors are shown to be more harmful to speech intelligibility than miss errors when the mixture signal-to-noise ratio (SNR) is below 0?dB. However, the relative importance between the two types of error is conditioned on the SNR level of the input speech signal. Based on these observations, a mask-based objective measure, the loudness weighted hit-false, is proposed for predicting speech intelligibility. The proposed objective measure shows significantly higher correlation with intelligibility compared to two existing mask-based objective measures. PMID:24815280

  16. Continuous Time-Frequency Transform for Unevenly Sampled Time Series and Significance Testing

    NASA Astrophysics Data System (ADS)

    Lenoir, Guillaume; Crucifix, Michel

    2014-05-01

    Spectral analysis is a common approach for the interpretation of climate time series. In particular, the continuous wavelet transform and the Gabor transform are generally well-suited for non-stationary, multi-periodic and highly noisy data. The purpose of this contribution is to propose a rigorous framework to estimate the significance of wavelet spectra given unevenly sampled data. To this end, we expand the theory developed by G. Foster [1], originally targeted for astronomical data, as follows: (i) Define the model: Significance testing is always based on a model, that needs to be properly defined. (ii) Define the parametric hypotheses H0 (null case) and H1 (alternative case), and attempt to find an appropriate statistical summary. The idea is to obtain a well-known distribution under H0, allowing an analytical approach and avoiding most of Monte-Carlo simulations which can be expensive in time. We also discuss the choice to be done for the analysis function of the time-frequency transform. Indeed, Morlet wavelet is often chosen, but it is not always the best option. Some examples of paleoclimate time series analysis will be given. Finally, we investigate whether considering the interpolated data to get a constant time step and using the traditional tools may lead to significant errors. Reference: [1] G. Foster. Wavelets for period analysis of unevenly sampled time series. The Astronomical Journal, 112(4):1709-1729, 1996.

  17. Relation between deep bioluminescence and oceanographic variables: A statistical analysis using time-frequency decompositions

    NASA Astrophysics Data System (ADS)

    Martini, S.; Nerini, D.; Tamburini, C.

    2014-09-01

    We consider the statistical analysis of a 1.7-year high-frequency sampled time series, between 2009 and 2010, recorded at the ANTARES observatory in the deep NW Mediterranean Sea (2475 m depth). The objective was to estimate relationships between bioluminescence and environmental time series (temperature, salinity and current speed). As this entire dataset is characterized by non-linearity and non-stationarity, two time-frequency decomposition methods (wavelet and Hilbert-Huang) were used. These mathematical methods are dedicated to the analysis of a signal at various time and frequencies scales. This work propose some statistical tools dedicated to the study of relationships between two time series. Our study highlights three events of high bioluminescence activity in March 2009, December 2009 and March 2010. We demonstrate that the two events occurring in March 2009 and 2010 are correlated to the arrival of newly formed deep water masses at frequencies of approximately 4.8×10-7 (period of 24.1 days). In contrast, the event in December 2009 is only correlated with current speed at frequencies of approximately 1.9×10-6 (period of 6.0 days). The use of both wavelet and Hilbert-Huang transformations has proven to be successful for the analysis of multivariate time series. These methods are well-suited in a context of the increasing number of long time series recorded in oceanography.

  18. Time-Frequency analysis of seismic signals using the Wigner-Ville Spectrum

    NASA Astrophysics Data System (ADS)

    Prieto, G. A.; Vernon, F.; Parker, R. L.

    2004-12-01

    Fourier analysis and the spectral characterization of time series have played an important role in modern seismological studies. The frequency contents of a stationary time series are generally expressed by the use of the power spectrum. In seismology, we deal with earthquake records that are non-stationary transient time sequences. The usual spectral analysis fails to provide an acceptable estimate of the frequency contents of the signal with time because temporal information is lost and thus it is unsuitable for earthquake records. Different approaches have been proposed in the last 25 years to obtain an appropriate time-frequency representation, with the restriction imposed by the uncertainty principle, precluding one to obtain arbitrarily fine resolution in time and frequency. The Wigner-Ville distribution (or its stochastic counterpart the Wigner-Ville spectrum) has many of the desired properties for a power distribution: reduces to the PSD for stationary signals, its real-valued everywhere and is capable of correctly reflecting input-output relationship for linear filters. It has also some drawbacks, mainly the positivity of all its values cannot be guaranteed, which would be desirable property in terms of a density function. We apply the Wigner-Ville spectrum estimation to earthquakes (M = 1-5) recorded by the ANZA seismic network in Southern California and discuss the results. A measure of the degree of non-stationarity of the stochastic process is estimated, to test if the assumption of locally stationarity of the earthquake record is acceptable.

  19. Tuning time-frequency methods for the detection of metered HF speech

    NASA Astrophysics Data System (ADS)

    Nelson, Douglas J.; Smith, Lawrence H.

    2002-12-01

    Speech is metered if the stresses occur at a nearly regular rate. Metered speech is common in poetry, and it can occur naturally in speech, if the speaker is spelling a word or reciting words or numbers from a list. In radio communications, the CQ request, call sign and other codes are frequently metered. In tactical communications and air traffic control, location, heading and identification codes may be metered. Moreover metering may be expected to survive even in HF communications, which are corrupted by noise, interference and mistuning. For this environment, speech recognition and conventional machine-based methods are not effective. We describe Time-Frequency methods which have been adapted successfully to the problem of mitigation of HF signal conditions and detection of metered speech. These methods are based on modeled time and frequency correlation properties of nearly harmonic functions. We derive these properties and demonstrate a performance gain over conventional correlation and spectral methods. Finally, in addressing the problem of HF single sideband (SSB) communications, the problems of carrier mistuning, interfering signals, such as manual Morse, and fast automatic gain control (AGC) must be addressed. We demonstrate simple methods which may be used to blindly mitigate mistuning and narrowband interference, and effectively invert the fast automatic gain function.

  20. Phase retrieval and time-frequency methods in the measurement of ultrashort laser pulses

    SciTech Connect

    DeLong, K.W.; Fittinghoff, D.N.; Ladera, C.L.; Trebino, R.

    1995-02-01

    Recently several techniques have become available to measure the time- (or frequency-) dependent intensity and phase of ultrashort laser pulses. One of these, Frequency-Resolved Optical Gating (FROG), is rigorous and has achieved single-laser-shot operation. FROG combines the concepts of time-frequency analysis in the form of spectrogram generation (in order to create a two-dimensional problem), and uses a phase-retrieval-based algorithm to invert the experimental data to yield the intensity and phase of the laboratory laser pulse. In FROG it is easy to generate a spectrogram of the unknown signal, and inversion of the spectrogram to recover the signal is the main goal. Because the temporal width of a femtosecond laser pulse is much shorter than anything achievable by electronics, FROG uses the pulse to measure itself. In FROG, the laser pulse is split into two replicas of itself by a partially reflecting beamsplitter, and the two replicas interact with each other in a medium with an instantaneous nonlinear-optical response. This interaction generates a signal field that is then frequency-resolved using a spectrometer. The spectrum of the signal field is measured for all relevant values of the temporal delay between the two pulses. Here, the authors employ FROG and FROG related techniques to measure the time-dependent intensity and phase of an ultrashort laser pulse.

  1. Joint Commission

    MedlinePLUS

    ... Updates America’s Hospitals: Improving Quality and Safety: The Joint Commission’s Annual Report 2015 Tuesday November 17, 2015 ... Center of Sarasota Read Full Testimonial | Read All Joint Commission Vision All people always experience the safest, ...

  2. Joint Disorders

    MedlinePLUS

    A joint is where two or more bones come together, like the knee, hip, elbow, or shoulder. Joints can be damaged by many types of injuries or diseases, including Arthritis - inflammation of a joint. It causes pain, stiffness, and swelling. Over time, ...

  3. High-resolution space-time quantification of soil moisture along a hillslope using joint analysis of ground penetrating radar and frequency domain reflectometry data

    NASA Astrophysics Data System (ADS)

    Tran, Anh Phuong; Bogaert, Patrick; Wiaux, François; Vanclooster, Marnik; Lambot, Sébastien

    2015-04-01

    We combined ground-penetrating radar (GPR) and frequency domain reflectometry (FDR) to assess the space-time variability of soil moisture along a hillslope. Time-lapse GPR and FDR measurements were conducted weekly during the period 23/03-08/06/2011 along a cultivated hillslope in the Belgian loam belt. A full-wave GPR model, a soil dielectric mixing model and the Debye equation were combined to directly estimate soil moisture from GPR measurements. Measured GPR data were well reproduced by the full-wave GPR model, resulting in a relatively good agreement between the GPR and FDR-derived soil moisture. Subsequently, we merged the soil moisture obtained from both techniques in a data fusion framework and we investigated its spatial and temporal variability. The results indicate that there was a high correlation between the spatial variability of soil moisture and topography as well as between its temporal variability and rainfall. A temporal stability analysis showed that soil moisture at the footslope is higher and more stable than that at the summits and backslopes. The proposed approach appears to be promising for assessing soil moisture at the hillslope scale with a relatively high space-time resolution.

  4. The time-frequency representation of the ERPs of face processing.

    PubMed

    Tang, Yingying; Liu, Dan; Li, Yingjie; Qiu, Yihong; Zhu, Yisheng

    2008-01-01

    In ERP studies of face processing, N170 and VPP were considered to reflect the structural encoding of faces in many researches. However, whether the VPP is the positive counterpart of the N170 from the same brain source is still a matter of debate. In present study, in order to address the debate we studied the oscillatory activities of event-related potentials (ERPs) during face processing. We recorded the ERPs in response to upright and inverted faces, and analyzed the time-frequency representation (TFR) by using the Smoothed Pseudo Wigner-Ville Distribution (SPWVD). The TFR of ERPs suggests that the oscillations at occipito-temporal sites (T5/T6) where the N170 was observed, were centralized in a higher frequency band (4-10 Hz) while the oscillations at the fronto-central site (Cz) with salient VPP, were more centralized in a lower frequency range(0-5 Hz). Therefore, we concluded that the face-sensitive N170 and VPP, associated with 'the structural encoding' stage of the face processing in Bruce & Young's model, reflect the activities from two different sources. Furthermore, different oscillatory activities were obtained at different face processing stages: 0-10 Hz oscillations around 100-200 ms post-stimulus are involved in face encoding processing, 0-4 Hz oscillations around 300-400 ms post-stimulus are involved in the later face identification and the enhanced activities in response to the inverted faces indicate a higher number of synchronous neuronal populations. PMID:19163617

  5. Seismic random noise attenuation and signal-preserving by multiple directional time-frequency peak filtering

    NASA Astrophysics Data System (ADS)

    Zhang, Chao; Li, Yue; Lin, Hong-bo; Yang, Bao-jun

    2015-01-01

    Time-frequency peak filtering (TFPF) is an effective method for seismic random noise attenuation. The linearity of the signal has a significant influence on the accuracy of the TFPF method. The higher the linearity of the signal to be filtered is, the better the denoising result is. With this in mind, and taking the lateral coherence of reflected events into account, we do TFPF along the reflected events to improve the degree of linearity and enhance the continuity of these events. The key factor to realize this idea is to find the traces of the reflected events. However, the traces of the events are too hard to obtain in the complicated field seismic data. In this paper, we propose a Multiple Directional TFPF (MD-TFPF), in which the filtering is performed in certain direction components of the seismic data. These components are obtained by a directional filter bank. In each direction component, we do TFPF along these decomposed reflected events (the local direction of the events) instead of the channel direction. The final result is achieved by adding up the filtering results of all decomposition directions of seismic data. In this way, filtering along the reflected events is implemented without accurately finding the directions. The effectiveness of the proposed method is tested on synthetic and field seismic data. The experimental results demonstrate that MD-TFPF can more effectively eliminate random noise and enhance the continuity of the reflected events with better preservation than the conventional TFPF, curvelet denoising method and F-X deconvolution method.

  6. Signal preserving and seismic random noise attenuation by Hurst exponent based time-frequency peak filtering

    NASA Astrophysics Data System (ADS)

    Zhang, Chao; Li, Yue; Lin, Hongbo; Yang, Baojun

    2015-11-01

    Attenuating random noise is of great significance in seismic data processing. In recent years, time-frequency peak filtering (TFPF) has been successfully applied to seismic random noise attenuation field. However, a fixed window length (WL) is used in the conventional TFPF. Since a short WL in the TFPF is used to preserve signals while a long WL can eliminate random noise effectively, signal preserving and noise attenuation cannot be balanced by a fixed WL especially when the signal-to-noise ratio of the noisy seismic record is low. Thus, we need to divide a noisy signal into signal and noise segments before the filtering. Then a short WL is used to the signal segments to preserve signals and a long WL is chosen for noise segments to eliminate random noise. In this paper, we test the smoothness of signals and random noise in time using the Hurst exponent which is a statistic for representing smoothness characteristics of signals. The time-series of signals with higher smoothness which lead to larger Hurst exponent values, however random noise is a random series in time without fixed waveforms and thus its smoothness is low, so the signal and noise segments can be divided by the Hurst exponent values. After the segmentation, we can adopt different filtering WLs in the TFPF for different segments to make a trade-off between signal preserving and random noise attenuation. Synthetic and real data experiments demonstrate that the proposed method can remove random noise from seismic record and preserve reflection events effectively.

  7. The benefits of using time-frequency analysis with synthetic aperture focusing technique

    SciTech Connect

    Albright, Austin E-mail: claytonda@ornl.gov; Clayton, Dwight E-mail: claytonda@ornl.gov

    2015-03-31

    Improvements in detection and resolution are always desired and needed. There are various instruments available for the inspection of concrete structures that can be used with confidence for detecting different defects. However, more often than not that confidence is heavily dependent on the experience of the operator rather than the clear, objective discernibility of the output of the instrument. The challenge of objective discernment is amplified when the concrete structures contain multiple layers of reinforcement, are of significant thickness, or both, such as concrete structures in nuclear power plants. We seek to improve and extend the usefulness of results produced using the synthetic aperture focusing technique (SAFT) on data collected from thick, complex concrete structures. A secondary goal is to improve existing SAFT results, with regards to repeatedly and objectively identifying defects and/or internal structure of concrete structures. Towards these goals, we are applying the time-frequency technique of wavelet packet decomposition and reconstruction using a mother wavelet that possesses the exact reconstruction property. However, instead of analyzing the coefficients of each decomposition node, we select and reconstruct specific nodes based on the frequency band it contains to produce a frequency band specific time-series representation. SAFT is then applied to these frequency specific reconstructions allowing SAFT to be used to visualize the reflectivity of a frequency band and that band's interaction with the contents of the concrete structure. We apply our technique to data sets collected using a commercial, ultrasonic linear array (MIRA) from two 1.5m × 2m × 25cm concrete test specimens. One specimen contains multiple layers of rebar. The other contains honeycomb, crack, and rebar bonding defect analogs. This approach opens up a multitude of possibilities for improved detection, readability, and overall improved objectivity. We will focus on improved defect/reinforcement isolation in thick and multilayered reinforcement environments. Additionally, the ability to empirically explore the possibility of a frequency-band-defect-type relationship or sensitivity becomes available.

  8. The Benefits of Using Time-Frequency Analysis with Synthetic Aperture Focusing Technique

    SciTech Connect

    Albright, Austin P; Clayton, Dwight A

    2015-01-01

    Improvements in detection and resolution are always desired and needed. There are various instruments available for the inspection of concrete structures that can be used with confidence for detecting different defects. However, more often than not that confidence is heavily dependent on the experience of the operator rather than the clear, objective discernibility of the output of the instrument. The challenge of objective discernment is amplified when the concrete structures contain multiple layers of reinforcement, are of significant thickness, or both, such as concrete structures in nuclear power plants. We seek to improve and extend the usefulness of results produced using the synthetic aperture focusing technique (SAFT) on data collected from thick, complex concrete structures. A secondary goal is to improve existing SAFT results, with regards to repeatedly and objectively identifying defects and/or internal structure of concrete structures. Towards these goals, we are applying the time-frequency technique of wavelet packet decomposition and reconstruction using a mother wavelet that possesses the exact reconstruction property. However, instead of analyzing the coefficients of each decomposition node, we select and reconstruct specific nodes based on the frequency band it contains to produce a frequency band specific time-series representation. SAFT is then applied to these frequency specific reconstructions allowing SAFT to be used to visualize the reflectivity of a frequency band and that band s interaction with the contents of the concrete structure. We apply our technique to data sets collected using a commercial, ultrasonic linear array (MIRA) from two 1.5m x 2m x 25cm concrete test specimens. One specimen contains multiple layers of rebar. The other contains honeycomb, crack, and rebar bonding defect analogs. This approach opens up a multitude of possibilities for improved detection, readability, and overall improved objectivity. We will focus on improved defect/reinforcement isolation in thick and multilayered reinforcement environments. Additionally, the ability to empirically explore the possibility of a frequency-band-defect-type relationship or sensitivity becomes available.

  9. Non-identical smoothing operators for estimating time-frequency interdependence in electrophysiological recordings

    NASA Astrophysics Data System (ADS)

    Mehrkanoon, Saeid; Breakspear, Michael; Daffertshofer, Andreas; Boonstra, Tjeerd W.

    2013-12-01

    Synchronization of neural activity from distant parts of the brain is crucial for the coordination of cognitive activities. Because neural synchronization varies both in time and frequency, time-frequency (T-F) coherence is commonly employed to assess interdependences in electrophysiological recordings. T-F coherence entails smoothing the cross and power spectra to ensure statistical consistency of the estimate, which reduces its T-F resolution. This trade-off has been described in detail when the cross and power spectra are smoothed using identical smoothing operators, which may yield spurious coherent frequencies. In this article, we examine the use of non-identical smoothing operators for the estimation of T-F interdependence, i.e., phase synchronization is characterized by phase locking between signals captured by the cross spectrum and we may hence improve the trade-off by selectively smoothing the auto spectra. We first show that the frequency marginal density of the present estimate is bound within [0,1] when using non-identical smoothing operators. An analytic calculation of the bias and variance of present estimators is performed and compared with the bias and variance of standard T-F coherence using Monte Carlo simulations. We then test the use of non-identical smoothing operators on simulated data, whose T-F properties are known through construction. Finally, we analyze empirical data from eyes-closed surface electroencephalography recorded in human subjects to investigate alpha-band synchronization. These analyses show that selectively smoothing the auto spectra reduces the bias of the estimator and may improve the detection of T-F interdependence in electrophysiological data at high temporal resolution.

  10. 4D time-frequency representation for binaural speech signal processing

    NASA Astrophysics Data System (ADS)

    Mikhael, Raed; Szu, Harold H.

    2006-04-01

    Hearing is the ability to detect and process auditory information produced by the vibrating hair cilia residing in the corti of the ears to the auditory cortex of the brain via the auditory nerve. The primary and secondary corti of the brain interact with one another to distinguish and correlate the received information by distinguishing the varying spectrum of arriving frequencies. Binaural hearing is nature's way of employing the power inherent in working in pairs to process information, enhance sound perception, and reduce undesired noise. One ear might play a prominent role in sound recognition, while the other reinforces their perceived mutual information. Developing binaural hearing aid devices can be crucial in emulating the working powers of two ears and may be a step closer to significantly alleviating hearing loss of the inner ear. This can be accomplished by combining current speech research to already existing technologies such as RF communication between PDAs and Bluetooth. Ear Level Instrument (ELI) developed by Micro-tech Hearing Instruments and Starkey Laboratories is a good example of a digital bi-directional signal communicating between a PDA/mobile phone and Bluetooth. The agreement and disagreement of arriving auditory information to the Bluetooth device can be classified as sound and noise, respectively. Finding common features of arriving sound using a four coordinate system for sound analysis (four dimensional time-frequency representation), noise can be greatly reduced and hearing aids would become more efficient. Techniques developed by Szu within an Artificial Neural Network (ANN), Blind Source Separation (BSS), Adaptive Wavelets Transform (AWT), and Independent Component Analysis (ICA) hold many possibilities to the improvement of acoustic segmentation of phoneme, all of which will be discussed in this paper. Transmitted and perceived acoustic speech signal will improve, as the binaural hearing aid will emulate two ears in sound localization, speech understanding in noisy environment, and loudness differentiation.

  11. Using wavelets to decompose the time frequency effects of monetary policy

    NASA Astrophysics Data System (ADS)

    Aguiar-Conraria, Luís; Azevedo, Nuno; Soares, Maria Joana

    2008-05-01

    Central banks have different objectives in the short and long run. Governments operate simultaneously at different timescales. Many economic processes are the result of the actions of several agents, who have different term objectives. Therefore, a macroeconomic time series is a combination of components operating on different frequencies. Several questions about economic time series are connected to the understanding of the behavior of key variables at different frequencies over time, but this type of information is difficult to uncover using pure time-domain or pure frequency-domain methods. To our knowledge, for the first time in an economic setup, we use cross-wavelet tools to show that the relation between monetary policy variables and macroeconomic variables has changed and evolved with time. These changes are not homogeneous across the different frequencies.

  12. Dartmouth College Computer Science Technical Report TR2002-431 Analysis of Protein Sequences Using Time Frequency and

    E-print Network

    of the Short-Time Fourier Transform and the Continuous Wavelet Transform together with amino acid Wavelet Transform (CWT) and the Short-Time Fourier Transform (STFT) to perform time-frequency analyses to interpret genomic data. In this two-fold study we explore techniques for locating critical amino acid

  13. Abstract--Time-frequency analysis of heart rate variability (HRV) makes it easier to evaluate how the balance

    E-print Network

    Carvalho, João Luiz

    Abstract--Time-frequency analysis of heart rate variability (HRV) makes it easier to evaluate how-regressive model can be used to calculate the Power Spectrum Density of HRV and to create an auto of optimal orders for different interpolation rates of the HRV signal are presented. Keywords--AR model order

  14. Identification of Damaged Wheat Kernels and Cracked-Shell Hazelnuts with Impact Acoustics Time-Frequency Patterns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new adaptive time-frequency (t-f) analysis and classification procedure is applied to impact acoustic signals for detecting hazelnuts with cracked shells and three types of damaged wheat kernels. Kernels were dropped onto a steel plate, and the resulting impact acoustic signals were recorded with ...

  15. Heart rate variability analysis based on time-frequency representation and entropies in hypertrophic cardiomyopathy patients.

    PubMed

    Clariá, F; Vallverdú, M; Baranowski, R; Chojnowska, L; Caminal, P

    2008-03-01

    In hypertrophic cardiomyopathy (HCM) patients there is an increased risk of premature death, which can occur with little or no warning. Furthermore, classification for sudden cardiac death on patients with HCM is very difficult. The aim of our study was to improve the prognostic value of heart rate variability (HRV) in HCM patients, giving insight into changes of the autonomic nervous system. In this way, the suitability of linear and nonlinear measures was studied to assess the HRV. These measures were based on time-frequency representation (TFR) and on Shannon and Rényi entropies, and compared with traditional HRV measures. Holter recordings of 64 patients with HCM and 55 healthy subjects were analyzed. The HCM patients consisted of two groups: 13 high risk patients, after aborted sudden cardiac death (SCD); 51 low risk patients, without SCD. Five-hour RR signals, corresponding to the sleep period of the subjects, were considered for the analysis as a comparable standard situation. These RR signals were filtered in the three frequency bands: very low frequency band (VLF, 0-0.04 Hz), low frequency band (LF, 0.04-0.15 Hz) and high frequency band (HF, 0.15-0.45 Hz). TFR variables based on instantaneous frequency and energy functions were able to classify HCM patients and healthy subjects (control group). Results revealed that measures obtained from TFR analysis of the HRV better classified the groups of subjects than traditional HRV parameters. However, results showed that nonlinear measures improved group classification. It was observed that entropies calculated in the HF band showed the highest statistically significant levels comparing the HCM group and the control group, p-value < 0.0005. The values of entropy measures calculated in the HCM group presented lower values, indicating a decreasing of complexity, than those calculated from the control group. Moreover, similar behavior was observed comparing high and low risk of premature death, the values of the entropy being lower in high risk patients, p-value < 0.05, indicating an increase of predictability. Furthermore, measures from information entropy, but not from TFR, seem to be useful for enhanced risk stratification in HCM patients with an increased risk of sudden cardiac death. PMID:18367814

  16. Time-frequency analysis of auditory-nerve-fiber and basilar-membrane click responses reveal glide irregularities and non-characteristic-frequency skirts

    NASA Astrophysics Data System (ADS)

    Lin, Tai; Guinan, John J.

    2004-07-01

    Although many properties of click responses can be accounted for by a single, frequency-dispersive traveling wave exciting a single, characteristic-frequency (CF) resonance, some properties, such as waxing and waning cannot. Joint time-frequency distributions (TFDs) were used to help understand click responses of cat single auditory-nerve (AN) fibers (CFs<4 kHz) and published measurements of chinchilla basilar-membrane (BM) motion. For CFs>800 Hz, the peak energy of the response decreased in latency and frequency as the level increased, as expected. However, at high levels the trend reversed for AN, but not BM, responses. Normalized TFDs, which show the frequency with the peak energy at each response time, revealed glides, as previously reported. Classical theory predicts smooth, upward glides. Instead, at low CFs there were downward glides, and at other CFs glides had substantial irregularities. Finally, click skirts, defined as the longest-latency part of click responses, sometimes showed deviations from CF for above-threshold sound levels. Most of these phenomena are not explained by a single, frequency-dispersive traveling wave exciting a single CF resonance, but they can be accounted for by the interaction of two (or more) excitation drives with different latencies and frequency contents.

  17. Temporomandibular Joint, Closed

    MedlinePLUS

    ... Oral Health > The Temporomandibular Joint, Closed The Temporomandibular Joint, Closed Main Content Title: The Temporomandibular Joint, Closed Description: The temporomandibular joint connects the lower ...

  18. Time-frequency analysis of non-stationary fusion plasma signals using an improved Hilbert-Huang transform

    SciTech Connect

    Liu, Yangqing Tan, Yi; Xie, Huiqiao; Wang, Wenhao; Gao, Zhe

    2014-07-15

    An improved Hilbert-Huang transform method is developed to the time-frequency analysis of non-stationary signals in tokamak plasmas. Maximal overlap discrete wavelet packet transform rather than wavelet packet transform is proposed as a preprocessor to decompose a signal into various narrow-band components. Then, a correlation coefficient based selection method is utilized to eliminate the irrelevant intrinsic mode functions obtained from empirical mode decomposition of those narrow-band components. Subsequently, a time varying vector autoregressive moving average model instead of Hilbert spectral analysis is performed to compute the Hilbert spectrum, i.e., a three-dimensional time-frequency distribution of the signal. The feasibility and effectiveness of the improved Hilbert-Huang transform method is demonstrated by analyzing a non-stationary simulated signal and actual experimental signals in fusion plasmas.

  19. Signal existence verification (SEV) for GPS low received power signal detection using the time-frequency approach.

    PubMed

    Jan, Shau-Shiun; Sun, Chih-Cheng

    2010-01-01

    The detection of low received power of global positioning system (GPS) signals in the signal acquisition process is an important issue for GPS applications. Improving the miss-detection problem of low received power signal is crucial, especially for urban or indoor environments. This paper proposes a signal existence verification (SEV) process to detect and subsequently verify low received power GPS signals. The SEV process is based on the time-frequency representation of GPS signal, and it can capture the characteristic of GPS signal in the time-frequency plane to enhance the GPS signal acquisition performance. Several simulations and experiments are conducted to show the effectiveness of the proposed method for low received power signal detection. The contribution of this work is that the SEV process is an additional scheme to assist the GPS signal acquisition process in low received power signal detection, without changing the original signal acquisition or tracking algorithms. PMID:22399903

  20. Ceramic joints

    DOEpatents

    Miller, Bradley J. (Worcester, MA); Patten, Jr., Donald O. (Sterling, MA)

    1991-01-01

    Butt joints between materials having different coefficients of thermal expansion are prepared having a reduced probability of failure of stress facture. This is accomplished by narrowing/tapering the material having the lower coefficient of thermal expansion in a direction away from the joint interface and not joining the narrow-tapered surface to the material having the higher coefficient of thermal expansion.

  1. Definitions of non-stationary vibration power for time-frequency analysis and computational algorithms based upon harmonic wavelet transform

    NASA Astrophysics Data System (ADS)

    Heo, YongHwa; Kim, Kwang-joon

    2015-02-01

    While the vibration power for a set of harmonic force and velocity signals is well defined and known, it is not as popular yet for a set of stationary random force and velocity processes, although it can be found in some literatures. In this paper, the definition of the vibration power for a set of non-stationary random force and velocity signals will be derived for the purpose of a time-frequency analysis based on the definitions of the vibration power for the harmonic and stationary random signals. The non-stationary vibration power, defined as the short-time average of the product of the force and velocity over a given frequency range of interest, can be calculated by three methods: the Wigner-Ville distribution, the short-time Fourier transform, and the harmonic wavelet transform. The latter method is selected in this paper because band-pass filtering can be done without phase distortions, and the frequency ranges can be chosen very flexibly for the time-frequency analysis. Three algorithms for the time-frequency analysis of the non-stationary vibration power using the harmonic wavelet transform are discussed. The first is an algorithm for computation according to the full definition, while the others are approximate. Noting that the force and velocity decomposed into frequency ranges of interest by the harmonic wavelet transform are constructed with coefficients and basis functions, for the second algorithm, it is suggested to prepare a table of time integrals of the product of the basis functions in advance, which are independent of the signals under analysis. How to prepare and utilize the integral table are presented. The third algorithm is based on an evolutionary spectrum. Applications of the algorithms to the time-frequency analysis of the vibration power transmitted from an excitation source to a receiver structure in a simple mechanical system consisting of a cantilever beam and a reaction wheel are presented for illustration.

  2. Time-frequency demodulation analysis based on iterative generalized demodulation for fault diagnosis of planetary gearbox under nonstationary conditions

    NASA Astrophysics Data System (ADS)

    Feng, Zhipeng; Chen, Xiaowang; Liang, Ming; Ma, Fei

    2015-10-01

    The vibration signal of planetary gearboxes exhibits the characteristics of both amplitude modulation (AM) and frequency modulation (FM), and thus has a complex sideband structure. Time-varying speed and/or load will result in time variant characteristic frequency components. Since the modulating frequency is related to the gear fault characteristic frequency, the AM and FM parts each alone contains the information of the gear fault. We propose a time-frequency amplitude and frequency demodulation analysis metbhod to avoid the complex time-variant sideband analysis, and thereby identify the time-variant gear fault characteristic frequency. We enhance the time-frequency analysis via iterative generalized demodulation (IGD). The time-varying amplitude and frequency demodulated spectra have fine time-frequency resolution and are free of cross term interferences. They do not involve complex time-variant sidebands, thus considerably facilitating fault diagnosis of planetary gearboxes under nonstationary conditions. The method is validated using both numerically simulated data and experimental signals.

  3. Joint pain

    MedlinePLUS

    ... both rest and exercise are important. Warm baths, massage, and stretching exercises should be used as often ... Does keeping the joint elevated help? Do medicines, massage, or applying heat reduce the pain? What other ...

  4. Compliant joint

    NASA Technical Reports Server (NTRS)

    Eklund, Wayne D. (inventor); Kerley, James J. (inventor)

    1990-01-01

    A compliant joint is provided for prosthetic and robotic devices which permits rotation in three different planes. The joint provides for the controlled use of cable under motion. Perpendicular outer mounting frames are joined by swaged cables that interlock at a center block. Ball bearings allow for the free rotation of the second mounting frame relative to the first mounting frame within a predetermined angular rotation that is controlled by two stop devices. The cables allow for compliance at the stops and the cables allow for compliance in six degrees of freedom enabling the duplication or simulation of the rotational movement and flexibility of a natural hip or knee joint, as well as the simulation of a joint designed for a specific robotic component for predetermined design parameters.

  5. Joint Problems

    MedlinePLUS

    ... ankles and toes. Other types of arthritis include gout or pseudogout. Sometimes, there is a mechanical problem ... for more information on osteoarthritis, rheumatoid arthritis and gout. How Common are Joint Problems? Osteoarthritis, which affects ...

  6. The Time-Frequency Signatures of Advanced Seismic Signals Generated by Debris Flows

    NASA Astrophysics Data System (ADS)

    Chu, C. R.; Huang, C. J.; Lin, C. R.; Wang, C. C.; Kuo, B. Y.; Yin, H. Y.

    2014-12-01

    The seismic monitoring is expected to reveal the process of debris flow from the initial area to alluvial fan, because other field monitoring techniques, such as the video camera and the ultrasonic sensor, are limited by detection range. For this reason, seismic approaches have been used as the detection system of debris flows over the past few decades. The analysis of the signatures of the seismic signals in time and frequency domain can be used to identify the different phases of debris flow. This study dedicates to investigate the different stages of seismic signals due to debris flow, including the advanced signal, the main front, and the decaying tail. Moreover, the characteristics of the advanced signals forward to the approach of main front were discussed for the warning purpose. This study presents a permanent system, composed by two seismometers, deployed along the bank of Ai-Yu-Zi Creek in Nantou County, which is one of the active streams with debris flow in Taiwan. The three axes seismometer with frequency response of 7 sec - 200 Hz was developed by the Institute of Earth Sciences (IES), Academia Sinica for the purpose to detect debris flow. The original idea of replacing the geophone system with the seismometer technique was for catching the advanced signals propagating from the upper reach of the stream before debris flow arrival because of the high sensitivity. Besides, the low frequency seismic waves could be also early detected because of the low attenuation. However, for avoiding other unnecessary ambient vibrations, the sensitivity of seismometer should be lower than the general seismometer for detecting teleseism. Three debris flows with different mean velocities were detected in 2013 and 2014. The typical triangular shape was obviously demonstrated in time series data and the spectrograms of the seismic signals from three events. The frequency analysis showed that enormous debris flow bearing huge boulders would induce low frequency seismic waves. Owing to the less attenuation of low frequency waves, advanced signals mainly ranged between 2 and 10 Hz were detected in several minutes prior to the arrival of the main surge of a debris flow. As the results, the prior time of the advanced signals could be used not only to extend the warning time, but also to identify the initial location of a developing debris flow.

  7. Time-Frequency Transform Techniques Applied to Ultra-wideband Ground-Penetrating Radar

    NASA Astrophysics Data System (ADS)

    Yedlin, M.; Cresp, A.; Dauviganc, J. Y.; Gaffet, S.; Sénéchal, G.; Fortino, N.; Pichot, C.; Aliferis, I.

    2009-04-01

    Background Recently, Dauvignac et al [1] utilized a ground penetrating radar unit consisting of an exponentially tapered slot antenna (ETSA) of the Vivaldi type, connected to an Agilent vector network analyzer to obtain a densely-sampled profile in the anti-blast tunnel of LSBB (Low-Noise inter-Disciplinary Underground Science & Technology Laboratory) located in Rustrel, France. The frequency data, from 150 MHz to 2 GHz, was inverse Fourier-transformed to obtain the time dependent data. Simultaneously, the same profile was obtained using a RAMAC 500 MHz ground-penetrating radar unit. Initial comparison of both data sets was done in the time-domain. Data obtained from the ETSA will be inverted using a constrained least squares algorithm, in order that the depth-dependent permittivity can be inferred. As a quality control, the RAMAC data will also be inverted. The resulting permittivity profiles obtained in both inversions will be used to image water content over a depth of several meters. Proposed Research It is well-known, qualitatively in the ground penetrating radar literature that high frequencies appear at early times, but generally are attenuated at later times, essentially due to the skin effect. However, a signal-processing verification of this well-known result is needed. We propose to use the Stockwell or S transform [2] to determine the temporal location of frequencies in both of the foregoing datasets. The S transform, a short-time Fourier transform with a frequency-dependent window, will be described and applied to synthetic data. Then the application of the S transform to the RAMAC and ETSA data will be presented, after each data set has undergone the same pre-processing. The S transform is completely linear and preserves the phase of the data, which allows for easy interpretation of the operations of filtering, due to the linear inverse of the forward S transform. Thus the S transform is ideal for comparing the temporal distribution of frequency in these two datasets. BIBLIOGRAPHY [1] DAUVIGNAC J.-Y., N. FORTINO, G. SENECHAL, A. CRESP, M. YEDLIN, S. GAFFET, D. ROUSSET, and C. PICHOT, "Ultra-Wideband GPR Imaging of the Vaucluse Karst Aquifer", American Geophysical Union, Fall Meeting 2008, Abstract #NS51A-08. [2] STOCKWELL R. G., L. MANSINHA, R. P. LOWE, "Localization of the complex spectrum: the S transform", IEEE Transactions on Signal Processing, vol.44, n°4, pp 998-1001, April 1996.

  8. ab out Joint Administration of Access Policies for oalition Resources

    E-print Network

    Gligor, Virgil D.

    1 Reasoning ab out Joint Administration of Access Policies for oalition Resources Himanshu Khurana argue that joint administration of access policies for a dynamic coalition formed by autonomous domains authorizing access to policy objects (e.g., ACLs). Joint authority over the issuance of such certificates

  9. Teaching Children with Autism to Respond to Joint Attention Initiations

    ERIC Educational Resources Information Center

    Martins, Megan P.; Harris, Sandra L.

    2006-01-01

    Children with autism fail to develop joint attention skills appropriate to developmental age. Joint attention is a predictor of ability in several core domains of autism including language, social development, affective sharing, and theory of mind capacity, thus establishing the significance of teaching joint attention. However, there is limited…

  10. A continuous wavelet transform-based method for time-frequency analysis of artefact-corrected heart rate variability data.

    PubMed

    Peters, C H L; Vullings, R; Rooijakkers, M J; Bergmans, J W M; Oei, S G; Wijn, P F F

    2011-10-01

    Time-frequency analysis of heart rate variability (HRV) provides relevant clinical information. However, time-frequency analysis is very sensitive to artefacts. Artefacts that are present in heart rate recordings may be corrected, but this reduces the variability in the signal and therefore adversely affects the accuracy of calculated spectral estimates. To overcome this limitation of traditional techniques for time-frequency analysis, a new continuous wavelet transform (CWT)-based method was developed in which parts of the scalogram that have been affected by artefact correction are excluded from power calculations. The method was evaluated by simulating artefact correction on HRV data that were originally free of artefacts. Commonly used spectral HRV parameters were calculated by the developed method and by the short-time Fourier transform (STFT), which was used as a reference. Except for the powers in the very low-frequency and low-frequency (LF) bands, powers calculated by the STFT proved to be extremely sensitive to artefact correction. The CWT-based calculations in the high-frequency and very high-frequency bands corresponded well with their theoretical values. The standard deviations of these powers, however, increase with the number of corrected artefacts which is the result of the non-stationarity of the R-R interval series that were analysed. The powers calculated in the LF band turned out to be slightly sensitive to artefact correction, but the results were acceptable up to 20% artefact correction. Therefore, the CWT-based method provides a valuable alternative for the analysis of HRV data that cannot be guaranteed to be free of artefacts. PMID:21849721

  11. Normal and hypoacoustic infant cry signal classification using time-frequency analysis and general regression neural network.

    PubMed

    Hariharan, M; Sindhu, R; Yaacob, Sazali

    2012-11-01

    Crying is the most noticeable behavior of infancy. Infant cry signals can be used to identify physical or psychological status of an infant. Recently, acoustic analysis of infant cry signal has shown promising results and it has been proven to be an excellent tool to investigate the pathological status of an infant. This paper proposes short-time Fourier transform (STFT) based time-frequency analysis of infant cry signals. Few statistical features are derived from the time-frequency plot of infant cry signals and used as features to quantify infant cry signals. General Regression Neural Network (GRNN) is employed as a classifier for discriminating infant cry signals. Two classes of infant cry signals are considered such as normal cry signals and pathological cry signals from deaf infants. To prove the reliability of the proposed features, two neural network models such as Multilayer Perceptron (MLP) and Time-Delay Neural Network (TDNN) trained by scaled conjugate gradient algorithm are also used as classifiers. The experimental results show that the GRNN classifier gives very promising classification accuracy compared to MLP and TDNN and the proposed method can effectively classify normal and pathological infant cries. PMID:21824676

  12. Q factor estimation from the amplitude spectrum of the time-frequency transform of stacked reflection seismic data

    NASA Astrophysics Data System (ADS)

    Lupinacci, Wagner Moreira; Oliveira, Sérgio Adriano Moura

    2015-03-01

    Attenuation is one factor that degrades the quality of reflection seismic subsurface imaging. It causes a progressive decrease in the seismic pulse energy and is also responsible for limiting seismic resolution. Currently, many methods exist for inverse Q filtering, which can be used to correct these effects to some extent; however, but all of these methods require the value of the Q factor to be known, and this information is rarely available. In this paper we present and evaluate three different strategies to derive the Q factor from the time-frequency amplitude spectrum of the seismic trace. They are based in the analyses of the amplitude decay trend curves that can be measured along time, along frequency or along a compound variable obtained from the time-frequency product. Some difficulties are highlighted, such as the impossibility to use short time window intervals that prevents the method from providing a precise map of the Q factor value of the subsurface layers. However, the Q factor estimation made in this way can be used to guide the parameterization of attenuation correction by means of inverse Q filtering applied to a stacked seismic section; this is demonstrated in a real data example.

  13. Experimental validation of a signal-based approach for structural earthquake damage detection using fractal dimension of time frequency feature

    NASA Astrophysics Data System (ADS)

    Tao, Dongwang; Mao, Chenxi; Zhang, Dongyu; Li, Hui

    2014-12-01

    This article extends a signal-based approach formerly proposed by the authors, which utilizes the fractal dimension of time frequency feature (FDTFF) of displacements, for earthquake damage detection of moment resist frame (MRF), and validates the approach with shaking table tests. The time frequency feature (TFF) of the relative displacement at measured story is defined as the real part of the coefficients of the analytical wavelet transform. The fractal dimension (FD) is to quantify the TFF within the fundamental frequency band using box counting method. It is verified that the FDTFFs at all stories of the linear MRF are identical with the help of static condensation method and modal superposition principle, while the FDTFFs at the stories with localized nonlinearities due to damage will be different from those at the stories without nonlinearities using the reverse-path methodology. By comparing the FDTFFs of displacements at measured stories in a structure, the damage-induced nonlinearity of the structure under strong ground motion can be detected and localized. Finally shaking table experiments on a 1:8 scale sixteen-story three-bay steel MRF with added frictional dampers, which generate local nonlinearities, are conducted to validate the approach.

  14. TIME-FREQUENCY ANALYSIS OF THE SUPERORBITAL MODULATION OF THE X-RAY BINARY SMC X-1 USING THE HILBERT-HUANG TRANSFORM

    SciTech Connect

    Hu, Chin-Ping; Chou, Yi; Yang, Ting-Chang; Su, Yi-Hao; Wu, Ming-Chya E-mail: yichou@astro.ncu.edu.tw

    2011-10-20

    The high-mass X-ray binary SMC X-1 exhibits a superorbital modulation with a dramatically varying period ranging between {approx}40 days and {approx}60 days. This research studies the time-frequency properties of the superorbital modulation of SMC X-1 based on the observations made by the All-Sky Monitor (ASM) onboard the Rossi X-ray Timing Explorer (RXTE). We analyzed the entire ASM database collected since 1996. The Hilbert-Huang transform (HHT), developed for non-stationary and nonlinear time-series analysis, was adopted to derive the instantaneous superorbital frequency. The resultant Hilbert spectrum is consistent with the dynamic power spectrum as it shows more detailed information in both the time and frequency domains. The RXTE observations show that the superorbital modulation period was mostly between {approx}50 days and {approx}65 days, whereas it changed to {approx}45 days around MJD 50,800 and MJD 54,000. Our analysis further indicates that the instantaneous frequency changed to a timescale of hundreds of days between {approx}MJD 51,500 and {approx}MJD 53,500. Based on the instantaneous phase defined by HHT, we folded the ASM light curve to derive a superorbital profile, from which an asymmetric feature and a low state with barely any X-ray emissions (lasting for {approx}0.3 cycles) were observed. We also calculated the correlation between the mean period and the amplitude of the superorbital modulation. The result is similar to the recently discovered relationship between the superorbital cycle length and the mean X-ray flux for Her X-1.

  15. Concrete Domains 

    E-print Network

    Kahn, Gilles; Plotkin, Gordon

    1993-01-01

    This paper introduces the theory of a particular kind of computation domains called concrete domains. The purpose of this theory is to find a satisfactory framework for the notions of coroutine computation and sequentiality ...

  16. Performance analysis for time-frequency MUSIC algorithm in presence of both additive noise and array calibration errors

    NASA Astrophysics Data System (ADS)

    Khodja, Mohamed; Belouchrani, Adel; Abed-Meraim, Karim

    2012-12-01

    This article deals with the application of Spatial Time-Frequency Distribution (STFD) to the direction finding problem using the Multiple Signal Classification (MUSIC)algorithm. A comparative performance analysis is performed for the method under consideration with respect to that using data covariance matrix when the received array signals are subject to calibration errors in a non-stationary environment. An unified analytical expression of the Direction Of Arrival (DOA) error estimation is derived for both methods. Numerical results show the effect of the parameters intervening in the derived expression on the algorithm performance. It is particularly observed that for low Signal to Noise Ratio (SNR) and high Signal to sensor Perturbation Ratio (SPR) the STFD method gives better performance, while for high SNR and for the same SPR both methods give similar performance.

  17. A time-frequency analysis of the dynamics of cortical networks of sleep spindles from MEG-EEG recordings.

    PubMed

    Zerouali, Younes; Lina, Jean-Marc; Sekerovic, Zoran; Godbout, Jonathan; Dube, Jonathan; Jolicoeur, Pierre; Carrier, Julie

    2014-01-01

    Sleep spindles are a hallmark of NREM sleep. They result from a widespread thalamo-cortical loop and involve synchronous cortical networks that are still poorly understood. We investigated whether brain activity during spindles can be characterized by specific patterns of functional connectivity among cortical generators. For that purpose, we developed a wavelet-based approach aimed at imaging the synchronous oscillatory cortical networks from simultaneous MEG-EEG recordings. First, we detected spindles on the EEG and extracted the corresponding frequency-locked MEG activity under the form of an analytic ridge signal in the time-frequency plane (Zerouali et al., 2013). Secondly, we performed source reconstruction of the ridge signal within the Maximum Entropy on the Mean framework (Amblard et al., 2004), yielding a robust estimate of the cortical sources producing observed oscillations. Lastly, we quantified functional connectivity among cortical sources using phase-locking values. The main innovations of this methodology are (1) to reveal the dynamic behavior of functional networks resolved in the time-frequency plane and (2) to characterize functional connectivity among MEG sources through phase interactions. We showed, for the first time, that the switch from fast to slow oscillatory mode during sleep spindles is required for the emergence of specific patterns of connectivity. Moreover, we show that earlier synchrony during spindles was associated with mainly intra-hemispheric connectivity whereas later synchrony was associated with global long-range connectivity. We propose that our methodology can be a valuable tool for studying the connectivity underlying neural processes involving sleep spindles, such as memory, plasticity or aging. PMID:25389381

  18. A multivariate time-frequency method to characterize the influence of respiration over heart period and arterial pressure

    NASA Astrophysics Data System (ADS)

    Orini, Michele; Bailón, Raquel; Laguna, Pablo; Mainardi, Luca T.; Barbieri, Riccardo

    2012-12-01

    Respiratory activity introduces oscillations both in arterial pressure and heart period, through mechanical and autonomic mechanisms. Respiration, arterial pressure, and heart period are, generally, non-stationary processes and the interactions between them are dynamic. In this study we present a methodology to robustly estimate the time course of cross spectral indices to characterize dynamic interactions between respiratory oscillations of heart period and blood pressure, as well as their interactions with respiratory activity. Time-frequency distributions belonging to Cohen's class are used to estimate time-frequency (TF) representations of coherence, partial coherence and phase difference. The characterization is based on the estimation of the time course of cross spectral indices estimated in specific TF regions around the respiratory frequency. We used this methodology to describe the interactions between respiration, heart period variability (HPV) and systolic arterial pressure variability (SAPV) during tilt table test with both spontaneous and controlled respiratory patterns. The effect of selective autonomic blockade was also studied. Results suggest the presence of common underling mechanisms of regulation between cardiovascular signals, whose interactions are time-varying. SAPV changes followed respiratory flow both in supine and standing positions and even after selective autonomic blockade. During head-up tilt, phase differences between respiration and SAPV increased. Phase differences between respiration and HPV were comparable to those between respiration and SAPV during supine position, and significantly increased during standing. As a result, respiratory oscillations in SAPV preceded respiratory oscillations in HPV during standing. Partial coherence was the most sensitive index to orthostatic stress. Phase difference estimates were consistent among spontaneous and controlled breathing patterns, whereas coherence was higher in spontaneous breathing. Parasympathetic blockade did not affect interactions between respiration and SAPV, reduced the coherence between SAPV and HPV and between respiration and HPV. Our results support the hypothesis that non-autonomic, possibly mechanically mediated, mechanisms also contributes to the respiratory oscillations in HPV. A small contribution of sympathetic activity on HPV-SAPV interactions around the respiratory frequency was also observed.

  19. Shoulder joint (image)

    MedlinePLUS

    ... is the most freely moving joint of the body. The shoulder joint can move in multiple directions therefore it is less stable than other joints and is more susceptible to injury. Dislocation of the shoulder joint is common and occurs ...

  20. Arthritis: Metacarpophalangeal (MP) Joint

    MedlinePLUS

    ... is completely destroyed, then joint replacement or joint fusion are effective surgical options. The joints can be ... useful, especially for older or less active individuals. Fusion—or making the joint solid—is an effective ...

  1. Joint assembly

    NASA Technical Reports Server (NTRS)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2010-01-01

    A joint assembly is provided which includes a drive assembly and a swivel mechanism. The drive assembly features a motor operatively associated with a plurality of drive shafts for driving auxiliary elements, and a plurality of swivel shafts for pivoting the drive assembly. The swivel mechanism engages the swivel shafts and has a fixable element that may be attached to a foundation. The swivel mechanism is adapted to cooperate with the swivel shafts to pivot the drive assembly with at least two degrees of freedom relative to the foundation. The joint assembly allows for all components to remain encased in a tight, compact, and sealed package, making it ideal for space, exploratory, and commercial applications.

  2. Abstract--We propose a time-frequency analysis based method to discriminate between undamaged and three types of

    E-print Network

    Minnesota, University of

    pistachios with closed and open shells. Initially maximum values and time domain modeling features were used for classification. A speech processing algorithm used to separate closed and open pistachio in [5] resulted in 99

  3. Wavelets, period-doubling, and time-frequency localization with application to organization of convection over the tropical western Pacific

    NASA Technical Reports Server (NTRS)

    Weng, Hengyi; Lau, K.-M.

    1994-01-01

    In this paper, preliminary results in using orthogonal and continuous wavelet transform (WT) to identify period doubling and time-frequency localization in both synthetic and real data are presented. First, the Haar WT is applied to synthetic time series derived from a simple nonlinear dynamical system- a first-order quadratic difference equation. Second, the complex Morlet WT is used to study the time-frequency localization of tropical convection based on a high-resolution Japanese Geostationary Meteorological Satellite infrared (IR) radiance dataset. The Haar WT of the synthetic time series indicates the presence and distinct separation of multiple frequencies in a period-doubling sequence. The period-doubling process generates a multiplicity of intermediate frequencies, which are manifested in the nonuniformity in time with respect to the phase of oscillations in the lower frequencies. Wavelet transform also enables the detection of extremely weak signals in high-order subharmonics resulting from the period-doubling bifurcations. These signals are either undetected or considered statistically insignificant by traditional Fourier analysis. The Morlet WT of the IR radiance dataset indicates the presence of multiple timescales, which are localized in both frequency and time. There are two regimes in the variation of IR radiance, corresponding to the wet and dry periods. Multiple timescales, ranging from semidiurnal, diurnal, synoptic, to intraseasonal with embedding structures, are active in the wet regime. In particular, synoptic variability is more prominent during the wet phase of an intensive intraseasonal cycle. These are not only consistent with, but also show more details than, previous findings by using other techniques. The phase-locking relationships among the oscillations with different time-scales suggest that both synoptic and intraseasonal variations may be mixed oscillations due to the interaction of self-excited oscillations in the tropical atmosphere and external forcings such as annual and diurnal solar radiation variations. Both examples show that WT is a powerful tool for analysis of phenomena involving multiscale interactions that exhibit localization in both frequency and time. A discussion on the caveats in the use of WT in geophysical data analysis is also presented.

  4. Compressive sampling of swallowing accelerometry signals using time-frequency dictionaries based on modulated discrete prolate spheroidal sequences

    NASA Astrophysics Data System (ADS)

    Sejdi?, Ervin; Can, Azime; Chaparro, Luis F.; Steele, Catriona M.; Chau, Tom

    2012-12-01

    Monitoring physiological functions such as swallowing often generates large volumes of samples to be stored and processed, which can introduce computational constraints especially if remote monitoring is desired. In this article, we propose a compressive sensing (CS) algorithm to alleviate some of these issues while acquiring dual-axis swallowing accelerometry signals. The proposed CS approach uses a time-frequency dictionary where the members are modulated discrete prolate spheroidal sequences (MDPSS). These waveforms are obtained by modulation and variation of discrete prolate spheroidal sequences (DPSS) in order to reflect the time-varying nature of swallowing acclerometry signals. While the modulated bases permit one to represent the signal behavior accurately, the matching pursuit algorithm is adopted to iteratively decompose the signals into an expansion of the dictionary bases. To test the accuracy of the proposed scheme, we carried out several numerical experiments with synthetic test signals and dual-axis swallowing accelerometry signals. In both cases, the proposed CS approach based on the MDPSS yields more accurate representations than the CS approach based on DPSS. Specifically, we show that dual-axis swallowing accelerometry signals can be accurately reconstructed even when the sampling rate is reduced to half of the Nyquist rate. The results clearly indicate that the MDPSS are suitable bases for swallowing accelerometry signals.

  5. A time-frequency analysis approach for condition monitoring of a wind turbine gearbox under varying load conditions

    NASA Astrophysics Data System (ADS)

    Antoniadou, I.; Manson, G.; Staszewski, W. J.; Barszcz, T.; Worden, K.

    2015-12-01

    This paper deals with the condition monitoring of wind turbine gearboxes under varying operating conditions. Generally, gearbox systems include nonlinearities so a simplified nonlinear gear model is developed, on which the time-frequency analysis method proposed is first applied for the easiest understanding of the challenges faced. The effect of varying loads is examined in the simulations and later on in real wind turbine gearbox experimental data. The Empirical Mode Decomposition (EMD) method is used to decompose the vibration signals into meaningful signal components associated with specific frequency bands of the signal. The mode mixing problem of the EMD is examined in the simulation part and the results in that part of the paper suggest that further research might be of interest in condition monitoring terms. For the amplitude-frequency demodulation of the signal components produced, the Hilbert Transform (HT) is used as a standard method. In addition, the Teager-Kaiser energy operator (TKEO), combined with an energy separation algorithm, is a recent alternative method, the performance of which is tested in the paper too. The results show that the TKEO approach is a promising alternative to the HT, since it can improve the estimation of the instantaneous spectral characteristics of the vibration data under certain conditions.

  6. Timing, Frequency and Environmental Conditions Associated with Mainstem–Tributary Movement by a Lowland River Fish, Golden Perch (Macquaria ambigua)

    PubMed Central

    Koster, Wayne M.; Dawson, David R.; O’Mahony, Damien J.; Moloney, Paul D.; Crook, David A.

    2014-01-01

    Tributary and mainstem connections represent important links for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in south-eastern Australia, using acoustic telemetry over four years (2007–2011). Fish were tagged and released in autumn 2007–2009 in the mid-Murray (n?=?42) and lower Goulburn (n?=?37) rivers within 3–6 km of the mid-Murray-lower Goulburn junction. 38% of tagged fish undertook mainstem–tributary movements, characterised mostly by temporary occupation followed by return of fish to the original capture river. Approximately 10% of tagged fish exhibited longer-term shifts between the mainstem and tributary. Movement of fish from the tributary into the mainstem occurred primarily during the spawning season and in some years coincided with the presence of golden perch eggs/larvae in drift samples in the mainstem. Many of the tributary-to-mainstem movements occurred during or soon after changes in flow. The movements of fish from the mainstem into the tributary were irregular and did not appear to be associated with spawning. The findings show that golden perch moved freely across the mainstem–tributary interface. This demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across geographic management units such as rivers. PMID:24788137

  7. Differential neural responses to acupuncture revealed by MEG using wavelet-based time-frequency analysis: a pilot study.

    PubMed

    You, Youbo; Bai, Lijun; Dai, Ruwei; Xue, Ting; Zhong, Chongguang; Feng, Yuanyuan; Wang, Hu; Liu, Zhenyu; Tian, Jie

    2011-01-01

    Acupoint specificity, lying at the core of the Traditional Chinese Medicine, still faces many controversies. As previous neuroimaging studies on acupuncture mainly adopted relatively low time-resolution functional magnetic resonance imaging (fMRI) technology and inappropriate block-designed experimental paradigm due to sustained effect, in the current study, we employed a single block-designed paradigm together with high temporal-resolution magnetoencephalography (MEG) technology. We applied time-frequency analysis based upon Morlet wavelet transforming approach to detect differential oscillatory brain dynamics induced by acupuncture at Stomach Meridian 36 (ST36) using a nearby nonacupoint (NAP) as control condition. We observed that frequency power changes were mainly restricted to delta band for both ST36 group and NAP group. Consistently increased delta band power in contralateral temporal regions and decreased power in the counterparts of ipsilateral hemisphere were detected following stimulation at ST36 on the right leg. Compared with ST36, no significant delta ranges were found in temporal regions in NAP group, illustrating different oscillatory brain patterns. Our results may provide additional evidence to support the specificity of acupuncture modulation effects. PMID:22255974

  8. Localizations of the derived category of a valuation domain

    E-print Network

    Localizations of the derived category of a valuation domain Jan St'ovícek (joint with Pavel Príhoda St'ovícek (Charles University) Localizations, valuation domains May 18, 2012 1 / 22 #12;Outline 1 Valuation domains 2 A hierarchy of triangulated localizations 3 Examples 4 About the proof Jan St

  9. Knee joint replacement

    MedlinePLUS

    Knee joint replacement is surgery to replace a knee joint with a man-made joint. The artificial joint is called a prosthesis . ... cartilage and bone are removed from the knee joint. Man-made pieces are then placed in the ...

  10. Joint Durability Where Next?

    E-print Network

    Joint Durability Where Next? Peter Taylor #12;The problem? · Some joints are deteriorating faster joints · Batch variability · Drainage · Salt treatment · Hand placed #12;Ames, IA · Non-distressed joint Spacing factor: 0.007in w/cm: 0.40 to 0.45 · Distressed joint Spacing factor: 0.005in w/cm: 0.42 - 0

  11. Decoding a bistable percept with integrated time-frequency representation of single-trial local field potential

    NASA Astrophysics Data System (ADS)

    Wang, Zhisong; Logothetis, Nikos K.; Liang, Hualou

    2008-12-01

    Bistable perception emerges when a stimulus under continuous view is perceived as the alternation of two mutually exclusive states. Such a stimulus provides a unique opportunity for understanding the neural basis of visual perception because it dissociates the perception from the visual input. In this paper we analyze the dynamic activity of local field potential (LFP), simultaneously collected from multiple channels in the middle temporal (MT) visual cortex of a macaque monkey, for decoding its bistable structure-from-motion (SFM) perception. Based on the observation that the discriminative information of neuronal population activity evolves and accumulates over time, we propose to select features from the integrated time-frequency representation of LFP using a relaxation (RELAX) algorithm and a sequential forward selection (SFS) algorithm with maximizing the Mahalanobis distance as the criterion function. The integrated-spectrogram based feature selection is much more robust and can achieve significantly better features than the instantaneous-spectrogram based feature selection. We exploit the support vector machines (SVM) classifier and the linear discriminant analysis (LDA) classifier based on the selected features to decode the reported perception on a single trial basis. Our results demonstrate the excellent performance of the integrated-spectrogram based feature selection and suggest that the features in the gamma frequency band (30-100 Hz) of LFP within specific temporal windows carry the most discriminative information for decoding bistable perception. The proposed integrated-spectrogram based feature selection approach may have potential for a myriad of applications involving multivariable time series such as brain-computer interfaces (BCI).

  12. Joint Instability and Osteoarthritis

    PubMed Central

    Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi

    2015-01-01

    Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA. PMID:25741184

  13. Joint x-ray

    MedlinePLUS

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  14. Shoulder Joint Replacement

    MedlinePLUS

    .org Shoulder Joint Replacement Page ( 1 ) Although shoulder joint replacement is less common than knee or hip replacement, it is just as successful in relieving joint pain. Shoulder replacement surgery was ?rst performed in ...

  15. Joint Replacement Surgery

    MedlinePLUS

    ... a Clinical Trial Journal Articles Arthritis July 2014 Joint Replacement Surgery: Health Information Basics for You and Your Family What Is Joint Replacement Surgery? Joint replacement surgery is removing a ...

  16. Temporomandibular Joint Disorder

    MedlinePLUS

    ... feeds delivered directly to your desktop! more... Temporomandibular Joint Disorder Article Chapters Temporomandibular Joint Disorder What is ... Updated: November 2008 Previous Next Related Articles: Temporomandibular Joint Disorder (TMD) Are You Biting Off More Than ...

  17. Joint Replacement (Finger and Wrist Joints)

    MedlinePLUS

    ... a Hand Therapist? Media Find a Hand Surgeon Joint Replacement Email to a friend * required fields From * ... name and customize your collection. DESCRIPTION In a joint replacement, the abnormal bone and lining structures of ...

  18. Hip joint replacement

    MedlinePLUS

    ... made joint. The artificial joint is called a prosthesis . ... thromboembolic disease in patients undergoing elective hip and knee arthopolasty: Evidence-based guideline and evidence report. American ...

  19. Spacesuit mobility joints

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C. (inventor)

    1978-01-01

    Joints for use in interconnecting adjacent segments of an hermetically sealed spacesuit which have low torques, low leakage and a high degree of reliability are described. Each of the joints is a special purpose joint characterized by substantially constant volume and low torque characteristics. Linkages which restrain the joint from longitudinal distension and a flexible, substantially impermeable diaphragm of tubular configuration spanning the distance between pivotally supported annuli are featured. The diaphragms of selected joints include rolling convolutions for balancing the joints, while various joints include wedge-shaped sections which enhance the range of motion for the joints.

  20. Spacesuit mobility knee joints

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C. (inventor)

    1979-01-01

    Pressure suit mobility joints are for use in interconnecting adjacent segments of an hermetically sealed spacesuit in which low torques, low leakage and a high degree of reliability are required. Each of the joints is a special purpose joint characterized by substantially constant volume and low torque characteristics and includes linkages which restrain the joint from longitudinal distension and includes a flexible, substantially impermeable diaphragm of tubular configuration spanning the distance between pivotally supported annuli. The diaphragms of selected joints include rolling convolutions for balancing the joints, while various joints include wedge-shaped sections which enhance the range of motion for the joints.

  1. Joint Concept Formation Huan Liu and Wilson X. Wen \\Lambda

    E-print Network

    Liu, Huan

    Joint Concept Formation Huan Liu and Wilson X. Wen \\Lambda Summary Many concept formation systems construct disjoint­concept trees. However, a priori imposed tree structures may restrict the application of these systems in some domains. A joint concept formation scheme is thus proposed, which learns from observation

  2. 442 IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 35, NO. 2, MARCH/APRIL 1999 An Adaptive Statistical TimeFrequency Method

    E-print Network

    Yazici, Birsen

    in the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS by the Electric Machines Committee of the IEEE Industry442 IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 35, NO. 2, MARCH/APRIL 1999 An Adaptive Statistical Time­Frequency Method for Detection of Broken Bars and Bearing Faults in Motors Using Stator

  3. Source identification and manipulation in stereo music recordings using frequency-domain signal processing

    NASA Astrophysics Data System (ADS)

    Avendano, Carlos

    2001-05-01

    A short-time frequency domain framework for source identification, separation, and manipulation in stereo music recordings is presented. Using a simplified model of the stereo mix, a similarity measure between the short-time fourier transforms (STFTs) of the input signals is computed to identify time-frequency regions occupied by each source based on the panning coefficients assigned to it during the mix. Individual sources are identified and manipulated by clustering time-frequency components with a given panning coefficient and frequency range. After modification, an inverse STFT is used to synthesize a time-domain processed signal. Applications of the technique to source suppression, enhancement and repanning will be described, and audio demonstrations will be presented to illustrate the results.

  4. Joint fluid Gram stain

    MedlinePLUS

    Gram stain of joint fluid ... A sample of joint fluid is needed. The fluid sample is sent to a lab where a small drop is placed in a ... on how to prepare for the removal of joint fluid, see joint fluid aspiration .

  5. Joint Information Extraction and Reasoning: A Scalable Statistical Relational Learning Approach

    E-print Network

    Cohen, William W.

    Joint Information Extraction and Reasoning: A Scalable Statistical Relational Learning Approach- tional learning model for joint information extraction and reasoning. More specifi- cally, we incorporate datasets from multiple domains; that joint learning and inference for IE and SL sig- nificantly improve

  6. Modulation-domain Kalman filtering for single-channel speech enhancement

    E-print Network

    Modulation-domain Kalman filtering for single-channel speech enhancement Stephen So , Kuldip K-domain Kalman filter (MDKF) and compare its performance with other time-domain and acoustic-domain speech changes of the mag- nitude spectrum for both speech and noise. Also, because the Kalman filter is a joint

  7. Kalman filter methods for real-time frequency and mode number estimation of MHD activity in tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Alves, D.; Coelho, R.; JET EFDA contributors, the

    2013-10-01

    Magnetohydrodynamic (MHD) activity in magnetically confined fusion experiments is often associated with detrimental effects such as increased radial transport and consequent loss of confinement. In particular, the (2,1) neoclassical tearing mode (NTM), when proceeding to mode-locking, is a potentially disruptive instability hence with the potential to compromise the mechanical integrity of the machine. It is therefore quite significant to be able to characterize in real-time the most virulent and performance limiting instabilities such that adequate mitigation or complete stabilization using feedback control methods are employed during the plasma discharge. This work proposes a Kalman filter (KF) based mechanism for providing, in real-time, the amplitude and phase evolution of instabilities within a predefined set of mode numbers. The method relies on two KF implementations: a non-linear KF isolating the non-stationary dominant signal component of a sensor measurement and subsequently a linear KF which projects the former, for a collection of sensors, onto a predefined set of mode numbers. A basic overview of algorithms commonly used for real-time mode number analysis is also presented along with applications of the proposed algorithm to recently recorded data of the Joint European Torus (JET) tokamak.

  8. Butt Joint Tool Commissioning

    SciTech Connect

    Martovetsky, N N

    2007-12-06

    ITER Central Solenoid uses butt joints for connecting the pancakes in the CS module. The principles of the butt joining of the CICC were developed by the JAPT during CSMC project. The difference between the CSMC butt joint and the CS butt joint is that the CS butt joint is an in-line joint, while the CSMC is a double joint through a hairpin jumper. The CS butt joint has to carry the hoop load. The straight length of the joint is only 320 mm, and the vacuum chamber around the joint has to have a split in the clamp shell. These requirements are challenging. Fig.1 presents a CSMC joint, and Fig.2 shows a CS butt joint. The butt joint procedure was verified and demonstrated. The tool is capable of achieving all specified parameters. The vacuum in the end was a little higher than the target, which is not critical and readily correctable. We consider, tentatively that the procedure is established. Unexpectedly, we discover significant temperature nonuniformity in the joint cross section, which is not formally a violation of the specs, but is a point of concern. All testing parameters are recorded for QA purposes. We plan to modify the butt joining tool to improve its convenience of operation and provide all features necessary for production of butt joints by qualified personnel.

  9. Pressure suit joint analyzer

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C.; Webbon, B. W. (inventors)

    1982-01-01

    A measurement system for simultaneously measuring torque and angular flexure in a pressure suit joint is described. One end of a joint under test is held rigid. A torque transducer is pivotably supported on the other movable end of a joint. A potentiometer is attached to the transducer by an arm. The wiper shaft of the potentiometer is gripped by a reference arm that rotates the wiper shaft the same angle as the flexure of joint. A signal is generated by the potentiometer which is representative of the joint flexure. A compensation circuit converts the output of the transducer to a signal representative of joint torque.

  10. DMBC: Domain Names & Web Hosting Domain Names

    E-print Network

    Stowell, Michael

    DMBC: Domain Names & Web Hosting Domain Names Top Level Domains .com .net .org .edu .gov .mil professional or personal life Always aim for a .com Top Level Domain as it is what 99.9% of the web or underscores in the domain name unless there is no other option Web Hosting Web Hosting Providers Web

  11. Arch & Chord Joint Detail; Crossbracing Center Joint Detail; Chord, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Arch & Chord Joint Detail; Crossbracing Center Joint Detail; Chord, Panel Post, Tie & Diagonal Brace Joint Detail; Chord, Panel Post, Tie & Crossbracing Joint Detail - Dunlapsville Covered Bridge, Spanning East Fork Whitewater River, Dunlapsville, Union County, IN

  12. Behavior of jointed pipelines

    SciTech Connect

    Singhal, A.C.

    1984-06-01

    Experimental data on the axial, bending and torsional behavior of ductile cast iron pipes with rubber gasket joints is presented. Analytical expressions are provided which predict the resistance mechanisms and behavior of the joints. The bending mechanism is found to be quite different from the axial and torsional mechanism. By repeating the tests in a specially designed soil box, the effects of burial depths are determined. A joint stiffness matrix including axial, bending and torsional effects is provided. The slip behavior of the joint changes the stiffness values, however this occurence may be dealt with by using an appropriate flag system placed within a computer program. To minimize axial compressional stresses and interlocking bending stresses at the joint, a minor geometrical change in the joint needs to be made. Joints with larger lip lengths provide more flexibility when subjected to axial compression or joint bending rotations.

  13. Joint Aspiration (Arthrocentesis)

    MedlinePLUS

    ... Kids Deal With Bullies Pregnant? What to Expect Joint Aspiration (Arthrocentesis) KidsHealth > Parents > Doctors & Hospitals > Medical Tests & Exams > Joint Aspiration (Arthrocentesis) Print A A A Text Size ...

  14. Large displacement spherical joint

    DOEpatents

    Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)

    2002-01-01

    A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.

  15. Temporomandibular Joint Dysfunction

    MedlinePLUS

    The temporomandibular joint (TMJ) connects your jaw to the side of your head. When it works well, it enables you to ... For people with TMJ dysfunction, problems with the joint and muscles around it may cause Pain that ...

  16. Culture - joint fluid

    MedlinePLUS

    Joint fluid culture ... fungi, or viruses grow. This is called a culture. If these germs are detected, other tests may ... is no special preparation needed for the lab culture. How to prepare for the removal of joint ...

  17. Hip joint injection

    MedlinePLUS

    ... injection is a shot of medicine into the hip joint. The medicine helps relieve pain and inflammation. It ... often caused by: Bursitis Arthritis Injury to the hip joint or surrounding area Overuse or strain from running ...

  18. Joint Enrollment Report, 2014

    ERIC Educational Resources Information Center

    Iowa Department of Education, 2014

    2014-01-01

    The Iowa Department of Education collects information on joint enrollment in Iowa's 15 community colleges. Jointly enrolled students are high school students enrolled in community college credit coursework. Most jointly enrolled students enroll through Senior Year Plus (SYP) programs such as Postsecondary Enrollment Options (PSEO) and concurrent…

  19. Monitoring groundwater-surface water interaction using time-series and time-frequency analysis of transient three-dimensional electrical resistivity changes

    SciTech Connect

    Johnson, Timothy C.; Slater, Lee; Ntarlagiannis, Dimitrios; Day-Lewis, Frederick D.; Elwaseif, Mehrez

    2012-08-22

    Time-lapse resistivity imaging is increasingly used to monitor hydrologic processes. Compared to conventional hydrologic measurements, surface time-lapse resistivity provides (1) superior spatial coverage in two or three dimensions, (2) potentially high-resolution information in time, and (3) information in the absence of wells. However, interpretation of time-lapse electrical tomograms is complicated by the ever increasing size and complexity of long-term, three-dimensional time-series conductivity datasets. Here, we use three-dimensional (3D) surface time-lapse electrical imaging to monitor subsurface electrical conductivity variations associated with stage-driven groundwater/surface-water interaction along a stretch of the Columbia River adjacent to the Hanford 300 Area, Hanford WA, USA. We reduce the resulting 3D conductivity time series using both correlation and time-frequency analysis to isolate a paleochannel causing enhanced groundwater/river-water interaction. Correlation analysis on the time-lapse imaging results concisely represents enhanced ground water/surface-water interaction within the paleochannel, and provides information concerning groundwater flow velocities. Time-frequency analysis using the Stockwell (S) Transform provides additional information by 1) identifying the stage periodicities driving ground water/river-water interaction due to upstream dam operations, 2) identifying segments in time-frequency space when these interactions are most active. These results provide new insight into the distribution and timing of river water intrusion into the Hanford 300 area, which has a governing influence on the behavior of a uranium plume left over from historical nuclear fuel processing operations.

  20. Monitoring groundwater-surface water interaction using time-series and time-frequency analysis of transient three-dimensional electrical resistivity changes

    NASA Astrophysics Data System (ADS)

    Johnson, T. C.; Slater, L. D.; Ntarlagiannis, D.; Day-Lewis, F. D.; Elwaseif, M.

    2012-07-01

    Time-lapse resistivity imaging is increasingly used to monitor hydrologic processes. Compared to conventional hydrologic measurements, surface time-lapse resistivity provides superior spatial coverage in two or three dimensions, potentially high-resolution information in time, and information in the absence of wells. However, interpretation of time-lapse electrical tomograms is complicated by the ever-increasing size and complexity of long-term, three-dimensional (3-D) time series conductivity data sets. Here we use 3-D surface time-lapse electrical imaging to monitor subsurface electrical conductivity variations associated with stage-driven groundwater-surface water interactions along a stretch of the Columbia River adjacent to the Hanford 300 near Richland, Washington, USA. We reduce the resulting 3-D conductivity time series using both time-series and time-frequency analyses to isolate a paleochannel causing enhanced groundwater-surface water interactions. Correlation analysis on the time-lapse imaging results concisely represents enhanced groundwater-surface water interactions within the paleochannel, and provides information concerning groundwater flow velocities. Time-frequency analysis using the Stockwell (S) transform provides additional information by identifying the stage periodicities driving groundwater-surface water interactions due to upstream dam operations, and identifying segments in time-frequency space when these interactions are most active. These results provide new insight into the distribution and timing of river water intrusion into the Hanford 300 Area, which has a governing influence on the behavior of a uranium plume left over from historical nuclear fuel processing operations.

  1. See What I See, Do as I Do: Promoting Joint Attention and Imitation in Preschoolers with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Warreyn, Petra; Roeyers, Herbert

    2014-01-01

    Since imitation and joint attention are both important abilities for young children and since children with autism spectrum disorder show a range of problems in these domains, imitation and joint attention are important targets for intervention. In this study, we examined the possibility of promoting imitation and joint attention by means of a…

  2. Multi-Sensor Detection with Particle Swarm Optimization for Time-Frequency Coded Cooperative WSNs Based on MC-CDMA for Underground Coal Mines.

    PubMed

    Xu, Jingjing; Yang, Wei; Zhang, Linyuan; Han, Ruisong; Shao, Xiaotao

    2015-01-01

    In this paper, a wireless sensor network (WSN) technology adapted to underground channel conditions is developed, which has important theoretical and practical value for safety monitoring in underground coal mines. According to the characteristics that the space, time and frequency resources of underground tunnel are open, it is proposed to constitute wireless sensor nodes based on multicarrier code division multiple access (MC-CDMA) to make full use of these resources. To improve the wireless transmission performance of source sensor nodes, it is also proposed to utilize cooperative sensors with good channel conditions from the sink node to assist source sensors with poor channel conditions. Moreover, the total power of the source sensor and its cooperative sensors is allocated on the basis of their channel conditions to increase the energy efficiency of the WSN. To solve the problem that multiple access interference (MAI) arises when multiple source sensors transmit monitoring information simultaneously, a kind of multi-sensor detection (MSD) algorithm with particle swarm optimization (PSO), namely D-PSO, is proposed for the time-frequency coded cooperative MC-CDMA WSN. Simulation results show that the average bit error rate (BER) performance of the proposed WSN in an underground coal mine is improved significantly by using wireless sensor nodes based on MC-CDMA, adopting time-frequency coded cooperative transmission and D-PSO algorithm with particle swarm optimization. PMID:26343660

  3. Multi-Sensor Detection with Particle Swarm Optimization for Time-Frequency Coded Cooperative WSNs Based on MC-CDMA for Underground Coal Mines

    PubMed Central

    Xu, Jingjing; Yang, Wei; Zhang, Linyuan; Han, Ruisong; Shao, Xiaotao

    2015-01-01

    In this paper, a wireless sensor network (WSN) technology adapted to underground channel conditions is developed, which has important theoretical and practical value for safety monitoring in underground coal mines. According to the characteristics that the space, time and frequency resources of underground tunnel are open, it is proposed to constitute wireless sensor nodes based on multicarrier code division multiple access (MC-CDMA) to make full use of these resources. To improve the wireless transmission performance of source sensor nodes, it is also proposed to utilize cooperative sensors with good channel conditions from the sink node to assist source sensors with poor channel conditions. Moreover, the total power of the source sensor and its cooperative sensors is allocated on the basis of their channel conditions to increase the energy efficiency of the WSN. To solve the problem that multiple access interference (MAI) arises when multiple source sensors transmit monitoring information simultaneously, a kind of multi-sensor detection (MSD) algorithm with particle swarm optimization (PSO), namely D-PSO, is proposed for the time-frequency coded cooperative MC-CDMA WSN. Simulation results show that the average bit error rate (BER) performance of the proposed WSN in an underground coal mine is improved significantly by using wireless sensor nodes based on MC-CDMA, adopting time-frequency coded cooperative transmission and D-PSO algorithm with particle swarm optimization. PMID:26343660

  4. Mechanics of Suture Joints

    NASA Astrophysics Data System (ADS)

    Li, Yaning; Song, Juha; Ortiz, Christine; Boyce, Mary; Ortiz Group/DMSE/MIT Team; Boyce Group/ME/MIT Team

    2011-03-01

    Biological sutures are joints which connect two stiff skeletal or skeletal-like components. These joints possess a wavy geometry with a thin organic layer providing adhesion. Examples of biological sutures include mammalian skulls, the pelvic assembly of the armored fish Gasterosteus aculeatus (the three-spined stickleback), and the suture joints in the shell of the red-eared slider turtle. Biological sutures allow for movement and compliance, control stress concentrations, transmit loads, reduce fatigue stress and absorb energy. In this investigation, the mechanics of the role of suture geometry in providing a naturally optimized joint is explored. In particular, analytical and numerical micromechanical models of the suture joint are constructed. The anisotropic mechanical stiffness and strength are studied as a function of suture wavelength, amplitude and the material properties of the skeletal and organic components, revealing key insights into the optimized nature of these ubiquitous natural joints.

  5. BUILDING MODEL ANALYSIS APPLICATIONS WITH THE JOINT UNIVERSAL PARAMETER IDENTIFICATION AND EVALUATION OF RELIABILITY (JUPITER) API

    EPA Science Inventory

    The open-source, public domain JUPITER (Joint Universal Parameter IdenTification and Evaluation of Reliability) API (Application Programming Interface) provides conventions and Fortran-90 modules to develop applications (computer programs) for analyzing process models. The input ...

  6. Compound solder joints

    NASA Technical Reports Server (NTRS)

    Batista, R. I.; Simonson, R. B.

    1976-01-01

    Joining technique prevents contamination, may be used to join dissimilar metal tubes, minimizes fluid and gas entrapment, expedites repairs, and can yield joints having leakage rates less than 0.000001 standard cubic cm He/min. Components of joint are solder sleeve, two solder rings, Teflon sleeve, and tubing to be joined.

  7. Joint Newspaper Operating Agreements.

    ERIC Educational Resources Information Center

    Parsons, Marie

    The number of competing daily newspapers in American cities has dwindled until only about 50 cities boast two papers. Of the newspapers in those cities, 23 now maintain separate editorial operations but have joint printing, advertising, and circulation departments. The concept of joint operation is 50 years old, dating from the Depression years…

  8. Sacroiliac joint pain - aftercare

    MedlinePLUS

    The sacroiliac joint (SIJ) is a term used to describe the place where the sacrum and the iliac bones join. The ... The main purpose of the joint is to connect the spine and the pelvis. As a result, there is very little movement at the SIJ. Major reasons ...

  9. Parameter time-frequency representations

    NASA Astrophysics Data System (ADS)

    Grenier, Y.

    1985-09-01

    The definition and representation of time varying spectra are discussed. The definitions of Priestley (1965), Tjostheim (1976) and Grenier (1984) are examined. It is shown that the adjusted average autoregressive models may be globally unstable in spite of the stability of their limit models. The analysis finds that the Tjostheim definition and the observable state definition are equivalent in the sense that the first respects the signal variance and the second the instantaneous local conditions.

  10. Time, Frequency and Physical Measurement.

    ERIC Educational Resources Information Center

    Hellwig, Helmut; And Others

    1978-01-01

    Describes several developments in atomic clocks and frequency standards pointing out the feasibility and practicality in adopting a unified standard of time and frequency to replace other base standards of length, mass, and temperature. (GA)

  11. MISR JOINT_AS Data

    Atmospheric Science Data Center

    2014-07-21

    Joint Aerosol Product (JOINT_AS) The MISR Level 3 Products are global or regional ... field campaigns at daily and monthly time scales. The Joint Aerosol product provides a monthly global statistical summary of MISR ...

  12. Modeling the Joint Statistics of Images in the Wavelet Domain

    E-print Network

    Simoncelli, Eero

    of visual images is enormous, and yet only a small fraction of these are likely to be encountered in a natural setting. Thus, a statistical prior model, even one that only partially captures these variations a linear decomposition is chosen to decorrelate the input signal. If one assumes that the model should

  13. Practical joint domain localised adaptive processing in homogeneous and

    E-print Network

    Adve, Raviraj

    siirveillnnce radar systetns opcratc in a scvcreand dynamic intcrfcrciicc cnvironmciil. The interference miiy bc dclibcratc (jamming) or clutter. The ability to detcct weak targcls, such as slow and sinall aircraft

  14. ROBUST VIDEO RESTORATION BY JOINT SPARSE AND LOW RANK MATRIX APPROXIMATION

    E-print Network

    Shen, Zuowei

    ROBUST VIDEO RESTORATION BY JOINT SPARSE AND LOW RANK MATRIX APPROXIMATION HUI JI, SIBIN HUANG, ZUOWEI SHEN, AND YUHONG XU Abstract. This paper presents a new video restoration scheme based domain, we formulate the video restoration problem as a joint sparse and low-rank matrix approximation

  15. Mapping knowledge domains: Characterizing PNAS

    PubMed Central

    Boyack, Kevin W.

    2004-01-01

    A review of data mining and analysis techniques that can be used for the mapping of knowledge domains is given. Literature mapping techniques can be based on authors, documents, journals, words, and/or indicators. Most mapping questions are related to research assessment or to the structure and dynamics of disciplines or networks. Several mapping techniques are demonstrated on a data set comprising 20 years of papers published in PNAS. Data from a variety of sources are merged to provide unique indicators of the domain bounded by PNAS. By using funding source information and citation counts, it is shown that, on an aggregate basis, papers funded jointly by the U.S. Public Health Service (which includes the National Institutes of Health) and non-U.S. government sources outperform papers funded by other sources, including by the U.S. Public Health Service alone. Grant data from the National Institute on Aging show that, on average, papers from large grants are cited more than those from small grants, with performance increasing with grant amount. A map of the highest performing papers over the 20-year period was generated by using citation analysis. Changes and trends in the subjects of highest impact within the PNAS domain are described. Interactions between topics over the most recent 5-year period are also detailed. PMID:14963238

  16. Pressure vessel flex joint

    NASA Technical Reports Server (NTRS)

    Kahn, Jon B. (inventor)

    1992-01-01

    An airtight, flexible joint is disclosed for the interfacing of two pressure vessels such as between the Space Station docking tunnel and the Space Shuttle Orbiter bulkhead adapter. The joint provides for flexibility while still retaining a structural link between the two vessels required due to the loading created by the internal/external pressure differential. The joint design provides for limiting the axial load carried across the joint to a specific value, a function returned in the Orbiter/Station tunnel interface. The flex joint comprises a floating structural segment which is permanently attached to one of the pressure vessels through the use of an inflatable seal. The geometric configuration of the joint causes the tension between the vessels created by the internal gas pressure to compress the inflatable seal. The inflation pressure of the seal is kept at a value above the internal/external pressure differential of the vessels in order to maintain a controlled distance between the floating segment and pressure vessel. The inflatable seal consists of either a hollow torus-shaped flexible bladder or two rolling convoluted diaphragm seals which may be reinforced by a system of straps or fabric anchored to the hard structures. The joint acts as a flexible link to allow both angular motion and lateral displacement while it still contains the internal pressure and holds the axial tension between the vessels.

  17. Compliant Joints For Robots

    NASA Technical Reports Server (NTRS)

    Kerley, James J., Jr.

    1990-01-01

    Compliant joints devised to accommodate misalignments of tools and/or workpieces with respect to robotic manipulators. Has characteristics and appearance of both universal-joint and cable-spring-type flexible shaft coupling. Compliance derived from elastic properties of short pieces of cable. Compliance of joint determined by lengths, distances between, relative orientations, thickness of strands, number of strands, material, amount of pretwist, and number of short pieces of cable. Worm-drive mechanism used to adjust lengths to vary compliance as needed during operation.

  18. Just How Joint Is Joint Action in Infancy? Malinda Carpenter

    E-print Network

    Carpenter, M.alinda

    Just How Joint Is Joint Action in Infancy? Malinda Carpenter Department of Developmental 2008; received in revised form 19 December 2008; accepted 20 January 2009 Abstract Joint action is central to countless aspects of human life. Here I examine the roots of joint action in infancy. First, I

  19. Joint Purchasing Consortium forms New Joint Procurement Committee

    E-print Network

    Victoria, University of

    Joint Purchasing Consortium forms New Joint Procurement Committee A new committee comprised of VPs the Consortium for a two year term. The Joint Procurement Committee members include: VP, Finance will be working on roles, responsibilities, and governance and implementation of the Wave 1 joint procurement

  20. Panel Post & Diagonal Brace Joint Detail; Crossbracing Center Joint ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Panel Post & Diagonal Brace Joint Detail; Crossbracing Center Joint Detail; Chord, Panel Post, Tie Bar, & Diagonal Brace Joint Detail; Chord, Tie Bar, & Crossbracing Joint Detail - Medora Bridge, Spanning East Fork of White River at State Route 235, Medora, Jackson County, IN

  1. Knee joint replacement - discharge

    MedlinePLUS

    ... ok to start again. People who have a prosthesis, such as an artificial joint, need to carefully ... in your wallet that says you have a prosthesis. You will need to take antibiotics before any ...

  2. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 2011-10-01 false Rail joints. 213.351 Section 213.351 Transportation...at Track Classes 6 and Higher § 213.351 Rail joints. (a) Each rail joint, insulated joint, and compromise joint...

  3. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 2014-10-01 false Rail joints. 213.351 Section 213.351 Transportation...at Track Classes 6 and Higher § 213.351 Rail joints. (a) Each rail joint, insulated joint, and compromise joint...

  4. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 2010-10-01 false Rail joints. 213.351 Section 213.351 Transportation...at Track Classes 6 and Higher § 213.351 Rail joints. (a) Each rail joint, insulated joint, and compromise joint...

  5. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 2013-10-01 false Rail joints. 213.351 Section 213.351 Transportation...at Track Classes 6 and Higher § 213.351 Rail joints. (a) Each rail joint, insulated joint, and compromise joint...

  6. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 2012-10-01 false Rail joints. 213.351 Section 213.351 Transportation...at Track Classes 6 and Higher § 213.351 Rail joints. (a) Each rail joint, insulated joint, and compromise joint...

  7. High pressure ceramic joint

    DOEpatents

    Ward, M.E.; Harkins, B.D.

    1993-11-30

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures. 4 figures.

  8. High pressure ceramic joint

    DOEpatents

    Ward, Michael E. (Poway, CA); Harkins, Bruce D. (San Diego, CA)

    1993-01-01

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

  9. Sub-Nyquist Field Trial Using Time Frequency Packed DP-QPSK Super-Channel Within Fixed ITU-T Grid

    E-print Network

    Potì, L; Berrettini, G; Fresi, F; Foggi, T; Secondini, M; Giorgi, L; Cavaliere, F; Hackett, S; Petronio, A; Nibbs, P; Forgan, R; Leong, A; Masciulli, R; Pfander, C

    2015-01-01

    Sub-Nyquist time frequency packing technique was demonstrated for the first time in a super channel field trial transmission over long-haul distances. The technique allows a limited spectral occupancy even with low order modulation formats. The transmission was successfully performed on a deployed Australian link between Sydney and Melbourne which included 995 km of uncompensated SMF with coexistent traffic. 40 and 100 Gb/s co-propagating channels were transmitted together with the super-channel in a 50 GHz ITU-T grid without additional penalty. The super-channel consisted of eight sub-channels with low-level modulation format, i.e. DP-QPSK, guaranteeing better OSNR robustness and reduced complexity with respect to higher order formats. At the receiver side, coherent detection was used together with iterative maximum-a-posteriori (MAP) detection and decoding. A 975 Gb/s DP-QPSK super-channel was successfully transmitted between Sydney and Melbourne within four 50GHz WSS channels (200 GHz). A maximum potential...

  10. Sub-Nyquist field trial using time frequency packed DP-QPSK super-channel within fixed ITU-T grid

    NASA Astrophysics Data System (ADS)

    Potì, L.; Meloni, G.; Berrettini, G.; Fresi, F.; Foggi, T.; Secondini, M.; Giorgi, L.; Cavaliere, F.; Hackett, S.; Petronio, A.; Nibbs, P.; Forgan, R.; Leong, A.; Masciulli, R.; Pfander, C.

    2015-06-01

    Sub-Nyquist time frequency packing technique was demonstrated for the first time in a super channel field trial transmission over long-haul distances. The technique allows a limited spectral occupancy even with low order modulation formats. The transmission was successfully performed on a deployed Australian link between Sydney and Melbourne which included 995 km of uncompensated SMF with coexistent traffic. 40 and 100 Gb/s co-propagating channels were transmitted together with the super-channel in a 50 GHz ITU-T grid without additional penalty. The super-channel consisted of eight sub-channels with low-level modulation format, i.e. DP-QPSK, guaranteeing better OSNR robustness and reduced complexity with respect to higher order formats. At the receiver side, coherent detection was used together with iterative maximum-a-posteriori (MAP) detection and decoding. A 975 Gb/s DP-QPSK super-channel was successfully transmitted between Sydney and Melbourne within four 50GHz WSS channels (200 GHz). A maximum potential SE of 5.58 bit/s/Hz was achieved with an OSNR=15.8 dB, comparable to the OSNR of the installed 100 Gb/s channels. The system reliability was proven through long term measurements. In addition, by closing the link in a loop back configuration, a potential SE*d product of 9254 bit/s/Hz*km was achieved.

  11. Spatially variable stage-driven groundwater-surface water interaction inferred from time-frequency analysis of distributed temperature sensing data

    NASA Astrophysics Data System (ADS)

    Mwakanyamale, Kisa; Slater, Lee; Day-Lewis, Frederick; Elwaseif, Mehrez; Johnson, Carole

    2012-03-01

    Characterization of groundwater-surface water exchange is essential for improving understanding of contaminant transport between aquifers and rivers. Fiber-optic distributed temperature sensing (FODTS) provides rich spatiotemporal datasets for quantitative and qualitative analysis of groundwater-surface water exchange. We demonstrate how time-frequency analysis of FODTS and synchronous river stage time series from the Columbia River adjacent to the Hanford 300-Area, Richland, Washington, provides spatial information on the strength of stage-driven exchange of uranium contaminated groundwater in response to subsurface heterogeneity. Although used in previous studies, the stage-temperature correlation coefficient proved an unreliable indicator of the stage-driven forcing on groundwater discharge in the presence of other factors influencing river water temperature. In contrast, S-transform analysis of the stage and FODTS data definitively identifies the spatial distribution of discharge zones and provided information on the dominant forcing periods (?2 d) of the complex dam operations driving stage fluctuations and hence groundwater-surface water exchange at the 300-Area.

  12. Time-frequency dynamics during sleep spindles on the EEG in rodents with a genetic predisposition to absence epilepsy (WAG/Rij rats)

    NASA Astrophysics Data System (ADS)

    Hramov, Alexander E.; Sitnikova, Evgenija Y.; Pavlov, Alexey N.; Grubov, Vadim V.; Koronovskii, Alexey A.; Khramova, Marina V.

    2015-03-01

    Sleep spindles are known to appear spontaneously in the thalamocortical neuronal network of the brain during slow-wave sleep; pathological processes in the thalamocortical network may be the reason of the absence epilepsy. The aim of the present work is to study developed changes in the time-frequency structure of sleep spindles during the progressive development of the absence epilepsy in WAG/Rij rats. EEG recordings were made at age 7 and 9 months. Automatic recognition and subsequent analysis of sleep spindles on the EEG were performed using the continuous wavelet transform. The duration of epileptic discharges and the total duration of epileptic activity were found to increase with age, while the duration of sleep spindles, conversely, decreased. In terms of the mean frequency, sleep spindles could be divided into three classes: `slow' (mean frequency 9.3Hz), `medium' (11.4Hz), and `fast' (13.5Hz). Slow and medium (transitional) spindles in five-month-old animals showed increased frequency from the beginning to the end of the spindle. The more intense the epilepsy is, the shorter are the durations of spindles of all types. The mean frequencies of `medium' and `fast' spindles were higher in rats with more intense signs of epilepsy. Overall, high epileptic activity in WAG/Rij rats was linked with significant changes in spindles of the transitional type, with less marked changes in the two traditionally identified types of spindle, slow and fast.

  13. Joint reversible data hiding and image encryption

    NASA Astrophysics Data System (ADS)

    Yang, Bian; Busch, Christoph; Niu, Xiamu

    2010-01-01

    Image encryption process is jointed with reversible data hiding in this paper, where the data to be hided are modulated by different secret keys selected for encryption. To extract the hided data from the cipher-text, the different tentative decrypted results are tested against typical random distribution in both spatial and frequency domain and the goodnessof- fit degrees are compared to extract one hided bit. The encryption based data hiding process is inherently reversible. Experiments demonstrate the proposed scheme's effectiveness on natural and textural images, both in gray-level and binary forms.

  14. Dissimilar metals joint evaluation

    NASA Technical Reports Server (NTRS)

    Wakefield, M. E.; Apodaca, L. E.

    1974-01-01

    Dissimilar metals tubular joints between 2219-T851 aluminum alloy and 304L stainless steel were fabricated and tested to evaluate bonding processes. Joints were fabricated by four processes: (1) inertia (friction) weldings, where the metals are spun and forced together to create the weld; (2) explosive welding, where the metals are impacted together at high velocity; (3) co-extrusion, where the metals are extruded in contact at high temperature to promote diffusion; and (4) swaging, where residual stresses in the metals after a stretching operation maintain forced contact in mutual shear areas. Fifteen joints of each type were prepared and evaluated in a 6.35 cm (2.50 in.) O.D. size, with 0.32 cm (0.13 in.) wall thickness, and 7.6 cm (3.0 in) total length. The joints were tested to evaluate their ability to withstand pressure cycle, thermal cycle, galvanic corrosion and burst tests. Leakage tests and other non-destructive test techniques were used to evaluate the behavior of the joints, and the microstructure of the bond areas was analyzed.

  15. 13. Sacroiliac joint pain.

    PubMed

    Vanelderen, Pascal; Szadek, Karolina; Cohen, Steven P; De Witte, Jan; Lataster, Arno; Patijn, Jacob; Mekhail, Nagy; van Kleef, Maarten; Van Zundert, Jan

    2010-01-01

    The sacroiliac joint accounts for approximately 16% to 30% of cases of chronic mechanical low back pain. Pain originating in the sacroiliac joint is predominantly perceived in the gluteal region, although pain is often referred into the lower and upper lumbar region, groin, abdomen, and/ or lower limb(s). Because sacroiliac joint pain is difficult to distinguish from other forms of low back pain based on history, different provocative maneuvers have been advocated. Individually, they have weak predictive value, but combined batteries of tests can help ascertain a diagnosis. Radiological imaging is important to exclude "red flags" but contributes little in the diagnosis. Diagnostic blocks are the diagnostic gold standard but must be interpreted with caution, because false-positive as well as false-negative results occur frequently. Treatment of sacroiliac joint pain is best performed in the context of a multidisciplinary approach. Conservative treatments address the underlying causes (posture and gait disturbances) and consist of exercise therapy and manipulation. Intra-articular sacroiliac joint infiltrations with local anesthetic and corticosteroids hold the highest evidence rating (1 B+). If the latter fail or produce only short-term effects, cooled radiofrequency treatment of the lateral branches of S1 to S3 (S4) is recommended (2 B+) if available. When this procedure cannot be used, (pulsed) radiofrequency procedures targeted at L5 dorsal ramus and lateral branches of S1 to S3 may be considered (2 C+). PMID:20667026

  16. Time-frequency analysis of neonatal cranial ultrasonic movies for selective detection of pulsatile tissues by avoiding probe-motion artifact

    NASA Astrophysics Data System (ADS)

    Fukuzawa, Masayuki; Tabata, Yuki; Izuwaki, Yusuke; Nakamori, Nobuyuki; Kitsunezuka, Yoshiki

    2015-03-01

    In order to detect the pulsatile tissues in neonatal cranial ultrasonic movies by avoiding probe-motion artifact, a time-frequency analysis has been performed in several movie fragments at typical three scenes: (a) a brain-lost, (b) a brain-captured and probe-stabilized, and (c) a brain-captured and probe-swayed ones. The pulsatile tissue, which is a key point of pediatric diagnosis, had successfully detected with an algorithm based on Fourier transform but it had required us to extract the probe-stabilized scene manually by visual observation of the movie. A spatial mean square of echo intensity Etot and a total AC power Ptot over a fan-shape of field of view were evaluated according to a power spectrum of a time-variation of 64 samples of echo intensity at each pixel in each movie fragment split from actual B-mode ultrasonic movies taken at coronal sections of a neonate. The results revealed that (1) significant low Etot was found at the brain-lost scene rather than that at the other scenes, and (2) lower Ptot was found at the probe-stabilized scene rather than the probe-swayed ones. This fact strongly suggests that the Etot and Ptot are promising features for automatic extraction of probe-stabilized scenes. It must lead to detect the pulsatile tissues selectively by avoiding probe-motion artifact and to realize systematic analysis of the whole of our extensive movie archives, which is useful not only for retrospective study of ischemic diseases but also for bedside diagnosis to stabilize the freehand ultrasonic probe.

  17. One hundred ways to process time, frequency, rate and scale in the central auditory system: a pattern-recognition meta-analysis

    PubMed Central

    Hemery, Edgar; Aucouturier, Jean-Julien

    2015-01-01

    The mammalian auditory system extracts features from the acoustic environment based on the responses of spatially distributed sets of neurons in the subcortical and cortical auditory structures. The characteristic responses of these neurons (linearly approximated by their spectro-temporal receptive fields, or STRFs) suggest that auditory representations are formed, as early as in the inferior colliculi, on the basis of a time, frequency, rate (temporal modulations) and scale (spectral modulations) analysis of sound. However, how these four dimensions are integrated and processed in subsequent neural networks remains unclear. In this work, we present a new methodology to generate computational insights into the functional organization of such processes. We first propose a systematic framework to explore more than a hundred different computational strategies proposed in the literature to process the output of a generic STRF model. We then evaluate these strategies on their ability to compute perceptual distances between pairs of environmental sounds. Finally, we conduct a meta-analysis of the dataset of all these algorithms' accuracies to examine whether certain combinations of dimensions and certain ways to treat such dimensions are, on the whole, more computationally effective than others. We present an application of this methodology to a dataset of ten environmental sound categories, in which the analysis reveals that (1) models are most effective when they organize STRF data into frequency groupings—which is consistent with the known tonotopic organization of receptive fields in auditory structures -, and that (2) models that treat STRF data as time series are no more effective than models that rely only on summary statistics along time—which corroborates recent experimental evidence on texture discrimination by summary statistics. PMID:26190996

  18. New Joint Sealants. Criteria, Design and Materials.

    ERIC Educational Resources Information Center

    Building Research Inst., Inc., Washington, DC.

    Contents include--(1) sealing concrete joints, (2) sealing glass and metal joints, (3) metal and glass joint sealants from a fabricator's viewpoint, (4) a theory of adhesion for joint sealants, (5) geometry of simple joint seals under strain, (6) joint sealant specifications from a manufacturer's viewpoint, (7) joint sealant requirements from an…

  19. Topological Domain Theory 

    E-print Network

    Battenfeld, Ingo

    2008-01-01

    This thesis presents Topological Domain Theory as a powerful and flexible framework for denotational semantics. Topological Domain Theory models a wide range of type constructions and can interpret many computational features. Furthermore, it has close connections to established frameworks for denotational semantics, as well as to well-studied mathematical theories, such as topology and computable analysis....We begin by describing the categories of Topological Domain Theory, and their categorical structure. In particular, we recover the basic constructions of domain theory, such as products, function spaces, fixed points and recursive types, in the context of Topological Domain Theory....As a central contribution, we give a detailed account of how computational effects can be modelled in Topological Domain Theory. Following recent work of Plotkin and Power, who proposed to construct effect monads via free algebra functors, this is done by showing that free algebras for a large class of parametrised equational theories exist in Topological Domain Theory. These parametrised equational theories are expressive enough to generate most of the standard examples of effect monads. Moreover, the free algebras in Topological Domain Theory are obtained by an explicit inductive construction, using only basic topological and set-theoretical principles....We also give a comparison of Topological and Classical Domain Theory. The category of omega-continuous dcpos embeds into Topological Domain Theory, and we prove that this embedding preserves the basic domain-theoretic constructions in most cases. We show that the classical powerdomain constructions on omega-continuous dcpos, including the probabilistic powerdomain, can be recovered in Topological Domain Theory.... of the categories of Topological Domain Theory in this realizability topos, and prove the corresponding categories to be internally complete and weakly small. This enables us to show that Topological Domain Theory can model the polymorphic lambda...In summary, this thesis shows that Topological Domain Theory supports a wide range of semantic constructions, including the standard domain-theoretic constructions, computational effects and polymorphism, all within a single setting....

  20. Internationalized Domain Names.

    ERIC Educational Resources Information Center

    Wielansky, Marc D.

    2002-01-01

    Reports on an investigation of what may appear at first to be an arcane topic--the internationalization of domain names on the Internet. Concludes that expanding domain names internationally poses challenges to the inherent open structure of the Internet; to its ease of use for those accustomed to Latin-alphabet-only domain names; and to corporate…

  1. Prosthetic Joint Infection

    PubMed Central

    Tande, Aaron J.

    2014-01-01

    SUMMARY Prosthetic joint infection (PJI) is a tremendous burden for individual patients as well as the global health care industry. While a small minority of joint arthroplasties will become infected, appropriate recognition and management are critical to preserve or restore adequate function and prevent excess morbidity. In this review, we describe the reported risk factors for and clinical manifestations of PJI. We discuss the pathogenesis of PJI and the numerous microorganisms that can cause this devastating infection. The recently proposed consensus definitions of PJI and approaches to accurate diagnosis are reviewed in detail. An overview of the treatment and prevention of this challenging condition is provided. PMID:24696437

  2. Johnson & Goodman Jointly Poisson Processes Jointly Poisson processes

    E-print Network

    Johnson & Goodman Jointly Poisson Processes Jointly Poisson processes Don H. Johnson and Ilan N. Goodman Electrical & Computer Engineering Department, MS380 Rice University Houston, Texas 77005­1892 {dhj for Gaussian 1 November 12, 2009 #12;Johnson & Goodman Jointly Poisson Processes random variables. A set

  3. Clad metal joint closure

    SciTech Connect

    Siebert, O.W.

    1985-04-09

    A plasma arc spray overlay of cladding metals is used over joints between clad metal pieces to provide a continuous cladding metal surface. The technique permits applying an overlay of a high melting point cladding metal to a cladding metal surface without excessive heating of the backing metal.

  4. Temporomandibular joint dislocation

    PubMed Central

    Sharma, Naresh Kumar; Singh, Akhilesh Kumar; Pandey, Arun; Verma, Vishal; Singh, Shreya

    2015-01-01

    Temporomandibular joint (TMJ) dislocation is an uncommon but debilitating condition of the facial skeleton. The condition may be acute or chronic. Acute TMJ dislocation is common in clinical practice and can be managed easily with manual reduction. Chronic recurrent TMJ dislocation is a challenging situation to manage. In this article, we discuss the comprehensive review of the different treatment modalities in managing TMJ dislocation.

  5. Realignment Subtalar Joint Arthrodesis.

    PubMed

    Hentges, Matthew J; Gesheff, Martin G; Lamm, Bradley M

    2016-01-01

    Subtalar joint arthrodesis is a commonly performed procedure for the correction of hindfoot deformity and/or the relief of pain related to osteoarthritis. The purpose of the present study was to provide preoperative and intraoperative objective radiographic parameters to improve the accuracy and long-term success of realignment arthrodesis of the subtalar joint. We retrospectively reviewed the data from 16 patients, 11 male (57.9%) and 8 female (42.1%) feet, who had undergone realignment subtalar joint arthrodesis. A total of 19 fusions were performed in 9 (47.4%) right and 10 (52.6%) left feet, with a mean follow-up period of 2 (range 1 to 4.8) years. The mean age at surgery was 54.5 (range 14 to 77) years. Statistically significant improvement in radiographic alignment was found in the anteroposterior talo-first metatarsal angle (p = .002), lateral talo-first metatarsal angle (p < .001), tibial-calcaneal angle (p < .001), and tibial-calcaneal distance (p < .001). A positive correlation was observed between the tibial-calcaneal angle and tibial-calcaneal distance (r = 0.825, p < .001). The statistically significant improvement in tibial-calcaneal alignment, in both angulation and distance, support our conclusions that proper realignment of the calcaneus to vertical and central under the tibia will lead to short-term success and, likely, long-term success of subtalar joint arthrodesis. PMID:26028600

  6. Shoulder Joint For Protective Suit

    NASA Technical Reports Server (NTRS)

    Kosmo, Joseph J.; Smallcombe, Richard D.

    1994-01-01

    Shoulder joint allows full range of natural motion: wearer senses little or no resisting force or torque. Developed for space suit, joint offers advantages in protective garments for underwater work, firefighting, or cleanup of hazardous materials.

  7. Joint Institute Marine and Atmospheric

    E-print Network

    Hawai'i at Manoa, University of

    Joint Institute for Marine and Atmospheric Research NATIONALOCEA NIC AND ATMOSPHERIC ADMINISTRATION Contribution 00-328 #12;ii This research is funded by Cooperative Agreement Number NA67RJ0154 between the Joint

  8. Rolling contact orthopaedic joint design

    E-print Network

    Slocum, Alexander Henry, Jr

    2013-01-01

    Arthroplasty, the practice of rebuilding diseased biological joints using engineering materials, is often used to treat severe arthritis of the knee and hip. Prosthetic joints have been created in a "biomimetic" manner to ...

  9. Anaerobic prosthetic joint infection.

    PubMed

    Shah, Neel B; Tande, Aaron J; Patel, Robin; Berbari, Elie F

    2015-12-01

    In an effort to improve mobility and alleviate pain from degenerative and connective tissue joint disease, an increasing number of individuals are undergoing prosthetic joint replacement in the United States. Joint replacement is a highly effective intervention, resulting in improved quality of life and increased independence [1]. By 2030, it is predicted that approximately 4 million total hip and knee arthroplasties will be performed yearly in the United States [2]. One of the major complications associated with this procedure is prosthetic joint infection (PJI), occurring at a rate of 1-2% [3-7]. In 2011, the Musculoskeletal Infectious Society created a unifying definition for prosthetic joint infection [8]. The following year, the Infectious Disease Society of America published practice guidelines that focused on the diagnosis and management of PJI. These guidelines focused on the management of commonly encountered organisms associated with PJI, including staphylococci, streptococci and select aerobic Gram-negative bacteria. However, with the exception of Propionibacterium acnes, management of other anaerobic organisms was not addressed in these guidelines [1]. Although making up approximately 3-6% of PJI [9,10], anaerobic microorganisms cause devastating complications, and similar to the more common organisms associated with PJI, these bacteria also result in significant morbidity, poor outcomes and increased health-care costs. Data on diagnosis and management of anaerobic PJI is mostly derived from case reports, along with a few cohort studies [3]. There is a paucity of published data outlining factors associated with risks, diagnosis and management of anaerobic PJI. We therefore reviewed available literature on anaerobic PJI by systematically searching the PubMed database, and collected data from secondary searches to determine information on pathogenesis, demographic data, clinical features, diagnosis and management. We focused our search on five commonly encountered anaerobic organisms associated with PJI. Since anaerobic PJI has also been linked to dental procedures, we also reviewed information on the use of dental procedures and prophylaxis, when available. PMID:26341272

  10. Cellular Pressure-Actuated Joint

    NASA Technical Reports Server (NTRS)

    McGuire, John R.

    2003-01-01

    A modification of a pressure-actuated joint has been proposed to improve its pressure actuation in such a manner as to reduce the potential for leakage of the pressurizing fluid. The specific joint for which the modification is proposed is a field joint in a reusable solid-fuel rocket motor (RSRM), in which the pressurizing fluid is a mixture of hot combustion gases. The proposed modification could also be applicable to other pressure-actuated joints of similar configuration.

  11. Determination of Parachute Joint Factors using Seam and Joint Testing

    NASA Technical Reports Server (NTRS)

    Mollmann, Catherine

    2015-01-01

    This paper details the methodology for determining the joint factor for all parachute components. This method has been successfully implemented on the Capsule Parachute Assembly System (CPAS) for the NASA Orion crew module for use in determining the margin of safety for each component under peak loads. Also discussed are concepts behind the joint factor and what drives the loss of material strength at joints. The joint factor is defined as a "loss in joint strength...relative to the basic material strength" that occurs when "textiles are connected to each other or to metals." During the CPAS engineering development phase, a conservative joint factor of 0.80 was assumed for each parachute component. In order to refine this factor and eliminate excess conservatism, a seam and joint testing program was implemented as part of the structural validation. This method split each of the parachute structural joints into discrete tensile tests designed to duplicate the loading of each joint. Breaking strength data collected from destructive pull testing was then used to calculate the joint factor in the form of an efficiency. Joint efficiency is the percentage of the base material strength that remains after degradation due to sewing or interaction with other components; it is used interchangeably with joint factor in this paper. Parachute materials vary in type-mainly cord, tape, webbing, and cloth -which require different test fixtures and joint sample construction methods. This paper defines guidelines for designing and testing samples based on materials and test goals. Using the test methodology and analysis approach detailed in this paper, the minimum joint factor for each parachute component can be formulated. The joint factors can then be used to calculate the design factor and margin of safety for that component, a critical part of the design verification process.

  12. Double slotted socket spherical joint

    DOEpatents

    Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)

    2001-05-22

    A new class of spherical joints is disclosed. These spherical joints are capable of extremely large angular displacements (full cone angles in excess of 270.degree.), while exhibiting no singularities or dead spots in their range of motion. These joints can improve or simplify a wide range of mechanical devices.

  13. JOINT PERFORMANCE Guide for Optimum

    E-print Network

    July 2012 JOINT PERFORMANCE Guide for Optimum of Concrete Pavements #12; #12;Guide for Optimum Joint Performance of Concrete Pavements i Technical Report Documentation Page 1. Report No. 2. Report Date Guide for Optimum Joint Performance of Concrete Pavements July 2012 6. Performing

  14. Phase 1 Program Joint Report

    NASA Technical Reports Server (NTRS)

    Nield, George C. (Editor); Vorobiev, Pavel Mikhailovich (Editor)

    1999-01-01

    This report consists of inputs from each of the Phase I Program Joint Working Groups. The Working Groups were tasked to describe the organizational structure and work processes that they used during the program, joint accomplishments, lessons learned, and applications to the International Space Station Program. This report is a top-level joint reference document that contains information of interest to both countries.

  15. Joint attention studies in normal and autistic children using NIRS

    NASA Astrophysics Data System (ADS)

    Chaudhary, Ujwal; Hall, Michael; Gutierrez, Anibal; Messinger, Daniel; Rey, Gustavo; Godavarty, Anuradha

    2011-03-01

    Autism is a socio-communication brain development disorder. It is marked by degeneration in the ability to respond to joint attention skill task, from as early as 12 to 18 months of age. This trait is used to distinguish autistic from nonautistic. In this study Near infrared spectroscopy (NIRS) is being applied for the first time to study the difference in activation and connectivity in the frontal cortex of typically developing (TD) and autistic children between 4-8 years of age in response to joint attention task. The optical measurements are acquired in real time from frontal cortex using Imagent (ISS Inc.) - a frequency domain based NIRS system in response to video clips which engenders a feeling of joint attention experience in the subjects. A block design consisting of 5 blocks of following sequence 30 sec joint attention clip (J), 30 sec non-joint attention clip (NJ) and 30 sec rest condition is used. Preliminary results from TD child shows difference in brain activation (in terms of oxy-hemoglobin, HbO) during joint attention interaction compared to the nonjoint interaction and rest. Similar activation study did not reveal significant differences in HbO across the stimuli in, unlike in an autistic child. Extensive studies are carried out to validate the initial observations from both brain activation as well as connectivity analysis. The result has significant implication for research in neural pathways associated with autism that can be mapped using NIRS.

  16. Formation of tough composite joints

    SciTech Connect

    Brun, M.K.

    1997-05-01

    Joints which exhibit tough fracture behavior were formed in a composite with a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. In composites with BN coatings fibers were aligned uniaxially, while composites with Si{sub 3}N{sub 4}-coated fibers had a 0/90{degree} architecture. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure have been proposed. Joints with a simple overlap geometry (only a few fingers) would have to be very long in order to prevent brittle failure. Typical failure in these joints is caused by a crack propagating along the interfaces between the joint fingers. Joints of the same overall length, but with geometry changed to be symmetric about the joint centerline and with an extra shear surface exhibited tough fractures accompanied with extensive fiber pullout. The initial matrix cracking of these joints was relatively low because cracks propagated easily through the ends of the fingers. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength from 9 to 25 MPa, by changing the fiber coating, increased matrix cracking and ultimate strength of the composite significantly. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints will permit building of structures containing joints with only a minor reduction of design stresses.

  17. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Rail joints. 213.351 Section 213.351... Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for the rail on which it is applied. (b) If a joint bar is cracked,...

  18. 17 CFR 300.105 - Joint accounts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Joint accounts. 300.105... Customers of Sipc Members § 300.105 Joint accounts. (a) A joint account shall be deemed to be a “qualifying joint account” if it is owned jointly, whether by the owners thereof as joint tenants with the right...

  19. 17 CFR 300.105 - Joint accounts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Joint accounts. 300.105... Customers of Sipc Members § 300.105 Joint accounts. (a) A joint account shall be deemed to be a “qualifying joint account” if it is owned jointly, whether by the owners thereof as joint tenants with the right...

  20. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Rail joints. 213.351 Section 213.351... Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for the rail on which it is applied. (b) If a joint bar is cracked,...

  1. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Rail joints. 213.351 Section 213.351... Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for the rail on which it is applied. (b) If a joint bar is cracked,...

  2. 17 CFR 300.105 - Joint accounts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Joint accounts. 300.105... Customers of Sipc Members § 300.105 Joint accounts. (a) A joint account shall be deemed to be a “qualifying joint account” if it is owned jointly, whether by the owners thereof as joint tenants with the right...

  3. 17 CFR 300.105 - Joint accounts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Joint accounts. 300.105... Customers of Sipc Members § 300.105 Joint accounts. (a) A joint account shall be deemed to be a “qualifying joint account” if it is owned jointly, whether by the owners thereof as joint tenants with the right...

  4. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Rail joints. 213.351 Section 213.351... Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for the rail on which it is applied. (b) If a joint bar is cracked,...

  5. Finger joint injuries.

    PubMed

    Prucz, Roni B; Friedrich, Jeffrey B

    2015-01-01

    Finger joint dislocations and collateral ligament tears are common athletic hand injuries. Treatment of the athlete requires a focus on safe return to play and maximizing function. Certain dislocations, such as proximal interphalangeal and distal interphalangeal volar dislocations, may be associated with tendon injuries and must be treated accordingly. Treatment of other dislocations is ultimately determined by postreduction stability, with many dislocations amenable to nonoperative treatment (ie, immobilization followed by rehabilitation). Protective splinting does not necessarily preclude athletic participation. Minor bone involvement typically does not affect the treatment plan, but significant articular surface involvement may necessitate surgical repair or stabilization. Percutaneous and internal fixation are the mainstays of surgical treatment. Treatment options that do not minimize recovery or allow the patient to return to protected play, such as external fixation, are generally avoided during the season of play. Undertreated joint injuries and unrecognized ligament injuries can result in long term disability. PMID:25455398

  6. Achieving joint benefits from joint implementation

    SciTech Connect

    Moomaw, W.R.

    1995-11-01

    Joint Implementation (JI) appears to have been born with Applied Energy Services Guatemala project in 1988. That project, to plant 52 million trees, protect existing forests from cutting and fire, and enhance rural development, is being implemented by CARE Guatemala to offset 120 per cent of the emissions of a small coal burning power plant that has been built in Connecticut. Since that time, several utilities and governments have initiated additional projects. Not all of these necessarily consist of tree planting in other countries, but may consist of energy efficiency or energy conservation programs designed to reduce carbon emissions by at least as much as the additional releases from a new facility. All JI projects share the characteristic of linking the release of greenhouse gases in an industrial country with an offset that reduces or absorbs a comparable amount in another country. The emitter in the industrial country is willing to pay for the reduction elsewhere because costs are less than they would be at home.

  7. Laboratory characterization of rock joints

    SciTech Connect

    Hsiung, S.M.; Kana, D.D.; Ahola, M.P.; Chowdhury, A.H.; Ghosh, A.

    1994-05-01

    A laboratory characterization of the Apache Leap tuff joints under cyclic pseudostatic and dynamic loads has been undertaken to obtain a better understanding of dynamic joint shear behavior and to generate a complete data set that can be used for validation of existing rock-joint models. Study has indicated that available methods for determining joint roughness coefficient (JRC) significantly underestimate the roughness coefficient of the Apache Leap tuff joints, that will lead to an underestimation of the joint shear strength. The results of the direct shear tests have indicated that both under cyclic pseudostatic and dynamic loadings the joint resistance upon reverse shearing is smaller than that of forward shearing and the joint dilation resulting from forward shearing recovers during reverse shearing. Within the range of variation of shearing velocity used in these tests, the shearing velocity effect on rock-joint behavior seems to be minor, and no noticeable effect on the peak joint shear strength and the joint shear strength for the reverse shearing is observed.

  8. Formation of tough composite joints

    SciTech Connect

    Brun, M.K.

    1998-12-01

    Joints that exhibited tough fracture behavior were formed in a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure were proposed. Joints with a simple overlap geometry (only a few fingers) had to be very long in order to prevent brittle failure. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength, by changing the fiber coating, significantly increased matrix cracking and ultimate strength of the joints. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints should permit building of structures containing joints with only a minor reduction of design stresses.

  9. Prosthetic elbow joint

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce C. (inventor)

    1994-01-01

    An artificial, manually positionable elbow joint for use in an upper extremity, above-elbow, prosthetic is described. The prosthesis provides a locking feature that is easily controlled by the wearer. The instant elbow joint is very strong and durable enough to withstand the repeated heavy loadings encountered by a wearer who works in an industrial, construction, farming, or similar environment. The elbow joint of the present invention comprises a turntable, a frame, a forearm, and a locking assembly. The frame generally includes a housing for the locking assembly and two protruding ears. The forearm includes an elongated beam having a cup-shaped cylindrical member at one end and a locking wheel having a plurality of holes along a circular arc on its other end with a central bore for pivotal attachment to the protruding ears of the frame. The locking assembly includes a collar having a central opening with a plurality of internal grooves, a plurality of internal cam members each having a chamfered surface at one end and a V-shaped slot at its other end; an elongated locking pin having a crown wheel with cam surfaces and locking lugs secured thereto; two coiled compression springs; and a flexible filament attached to one end of the elongated locking pin and extending from the locking assembly for extending and retracting the locking pin into the holes in the locking wheel to permit selective adjustment of the forearm relative to the frame. In use, the turntable is affixed to the upper arm part of the prosthetic in the conventional manner, and the cup-shaped cylindrical member on one end of the forearm is affixed to the forearm piece of the prosthetic in the conventional manner. The elbow joint is easily adjusted and locked between maximum flex and extended positions.

  10. Stochastic Chemical Reactions in Micro-domains

    E-print Network

    D. Holcman; Z. Schuss

    2004-12-25

    Traditional chemical kinetics may be inappropriate to describe chemical reactions in micro-domains involving only a small number of substrate and reactant molecules. Starting with the stochastic dynamics of the molecules, we derive a master-diffusion equation for the joint probability density of a mobile reactant and the number of bound substrate in a confined domain. We use the equation to calculate the fluctuations in the number of bound substrate molecules as a function of initial reactant distribution. A second model is presented based on a Markov description of the binding and unbinding and on the mean first passage time of a molecule to a small portion of the boundary. These models can be used for the description of noise due to gating of ionic channels by random binding and unbinding of ligands in biological sensor cells, such as olfactory cilia, photo-receptors, hair cells in the cochlea.

  11. Joint Temporal Density Measurements for Two-Photon State Characterization

    E-print Network

    Onur Kuzucu; Franco N. C. Wong; Sunao Kurimura; Sergey Tovstonog

    2008-07-10

    We demonstrate a new technique for characterizing two-photon quantum states based on joint temporal correlation measurements using time resolved single photon detection by femtosecond upconversion. We measure for the first time the joint temporal density of a two-photon entangled state, showing clearly the time anti-correlation of the coincident-frequency entangled photon pair generated by ultrafast spontaneous parametric down-conversion under extended phase-matching conditions. The new technique enables us to manipulate the frequency entanglement by varying the down-conversion pump bandwidth to produce a nearly unentangled two-photon state that is expected to yield a heralded single-photon state with a purity of 0.88. The time-domain correlation technique complements existing frequency-domain measurement methods for a more complete characterization of photonic entanglement in quantum information processing.

  12. Modeling Protein Domain Function

    ERIC Educational Resources Information Center

    Baker, William P.; Jones, Carleton "Buck"; Hull, Elizabeth

    2007-01-01

    This simple but effective laboratory exercise helps students understand the concept of protein domain function. They use foam beads, Styrofoam craft balls, and pipe cleaners to explore how domains within protein active sites interact to form a functional protein. The activity allows students to gain content mastery and an understanding of the…

  13. Time Domain Angelo Montanari

    E-print Network

    Chomicki, Jan

    Time Domain Angelo Montanari and Jan Chomicki+ Dipartimento di Matematica e Informatica, Universit at Buffalo, SUNY, USA Synonyms Temporal domain, temporal structure Definition In its full generality, a time on- tologies. In the database context, the most common temporal ontology takes time in- stants

  14. Metal to ceramic sealed joint

    DOEpatents

    Lasecki, John V. (Livonia, MI); Novak, Robert F. (Farmington Hills, MI); McBride, James R. (Ypsilanti, MI)

    1991-01-01

    A metal to ceramic sealed joint which can withstand wide variations in temperature and maintain a good seal is provided for use in a device adapted to withstand thermal cycling from about 20 to about 1000 degrees C. The sealed joint includes a metal member, a ceramic member having an end portion, and an active metal braze forming a joint to seal the metal member to the ceramic member. The joint is positioned remote from the end portion of the ceramic member to avoid stresses at the ends or edges of the ceramic member. The sealed joint is particularly suited for use to form sealed metal to ceramic joints in a thermoelectric generator such as a sodium heat engine where a solid ceramic electrolyte is joined to metal parts in the system.

  15. Metal to ceramic sealed joint

    DOEpatents

    Lasecki, J.V.; Novak, R.F.; McBride, J.R.

    1991-08-27

    A metal to ceramic sealed joint which can withstand wide variations in temperature and maintain a good seal is provided for use in a device adapted to withstand thermal cycling from about 20 to about 1000 degrees C. The sealed joint includes a metal member, a ceramic member having an end portion, and an active metal braze forming a joint to seal the metal member to the ceramic member. The joint is positioned remote from the end portion of the ceramic member to avoid stresses at the ends or edges of the ceramic member. The sealed joint is particularly suited for use to form sealed metal to ceramic joints in a thermoelectric generator such as a sodium heat engine where a solid ceramic electrolyte is joined to metal parts in the system. 11 figures.

  16. Strength of Welded Aircraft Joints

    NASA Technical Reports Server (NTRS)

    Brueggeman, W C

    1937-01-01

    This investigation is a continuation of work started in 1928 and described in NACA-TR-348 which shows that the insertion of gusset plates was the most satisfactory way of strengthening a joint. Additional tests of the present series show that joints of this type could be improved by cutting out the portion of the plate between the intersecting tubes. T and lattice joints in thin-walled tubing 1 1/2 by 0.020 inch have somewhat lower strengths than joints in tubing of greater wall thickness because of failure by local buckling. In welding the thin-walled tubing, the recently developed "carburizing flux" process was found to be the only method capable of producing joints free from cracks. The "magnetic powder" inspection was used to detect cracks in the joints and flaws in the tubing.

  17. Osteoarthritis: The Peripheral Joints

    PubMed Central

    Robinson, Harold S.

    1981-01-01

    Understanding of osteoarthritis has increased: the simplistic “wear and tear” concept no longer holds and this has positive clinical implications. A parallel development has taken place in treatment techniques: there is increasing expertise in the use of physical measures and in new orthopedic reconstructive surgical approaches to multiple joints. This gives the physician alternative approaches to the patient with painful and disabling osteoarthritis. The timing of these treatment options and some considerations which lead to orthopedic referral are considered in this general discussion. Imagesp285-aFig. 1Fig. 2Fig. 3 PMID:20469342

  18. Posttraumatic Temporomandibular Joint Disorders

    PubMed Central

    Giannakopoulos, Helen E.; Quinn, Peter D.; Granquist, Eric; Chou, Joli C.

    2009-01-01

    The temporomandibular joint (TMJ) has many essential functions. None of its components are exempt from injury. Facial asymmetry, malocclusion, disturbances in growth, osteoarthritis, and ankylosis can manifest as complications from trauma to the TMJ. The goals of initial treatment include achievement of pretraumatic function, restoration of facial symmetry, and resolution of pain. These same objectives hold true for late repairs and reconstruction of the TMJ apparatus. Treatment is demanding, and with opposing approaches. The following article explores various treatment options for problems presenting as a result of a history of trauma to the TMJ. PMID:22110802

  19. Bladder operated robotic joint

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A. (inventor)

    1993-01-01

    This invention is a robotic joint which is operated by inflatable bladders and which can be used in applications where it is desired to move or hold an object. A support block supports an elongated plate to which is pivotally attached a finger. A tension strip passes over a lever attached to the finger and is attached at its ends to the support block on opposite sides of the plate. Bladders positioned between the plate and the tension strip on opposite sides of the plate can be inflated by pumps to pivot the finger, with one of the bladders being inflated while the other is being deflated.

  20. Joint custody: solution or illusion?

    PubMed

    Benedek, E P; Benedek, R S

    1979-12-01

    Although the phrase "joint custody" is in popular use, the concept lacks standard definitin; parents who express interest in this form of disposition have widely differing objectives and expectations. The authors discuss the need for determining the primary objectives of the parties involved and for exploring the potential for achieving these through joint custody as well as through other alternatives. They examine the benefits of joint custody as well as the risks engendered by this type of arrangement and make a number of specific recommendations. They conclude that joint custody should be considered and explored, together with other available alternatives, and awarded only in appropriate cases. PMID:507203

  1. Disorders of the sacroiliac joint.

    PubMed

    Sizer, Phillip S; Phelps, Valerie; Thompsen, Kirk

    2002-03-01

    Controversies have surrounded the sacroiliac joint. The sacroiliac joint (SIJ) is a considerably complex and strong joint with limited mobility, mechanically serving as a force transducer and a shock absorber. Anatomical changes are seen in the SIJ throughout an individual's lifetime. The ligamentous system associated with the SIJ serves to enhance stability and offer proprioceptive feedback in context with the rich plexus of articular receptors. Stability in the SIJ is related to form and force closure. Movement in the SIJ is 3-D about an axis outside of the joint. The functional examination of the SIJ is related to a clinical triad. PMID:17134467

  2. Joint Interdisciplinary Earth Science Information Center

    NASA Technical Reports Server (NTRS)

    Kafatos, Menas

    2004-01-01

    The report spans the three year period beginning in June of 2001 and ending June of 2004. Joint Interdisciplinary Earth Science Information Center's (JIESIC) primary purpose has been to carry out research in support of the Global Change Data Center and other Earth science laboratories at Goddard involved in Earth science, remote sensing and applications data and information services. The purpose is to extend the usage of NASA Earth Observing System data, microwave data and other Earth observing data. JIESIC projects fall within the following categories: research and development; STW and WW prototyping; science data, information products and services; and science algorithm support. JIESIC facilitates extending the utility of NASA's Earth System Enterprise (ESE) data, information products and services to better meet the science data and information needs of a number of science and applications user communities, including domain users such as discipline Earth scientists, interdisciplinary Earth scientists, Earth science applications users and educators.

  3. Jointly Sponsored Research Program

    SciTech Connect

    Everett A. Sondreal; John G. Hendrikson; Thomas A. Erickson

    2009-03-31

    U.S. Department of Energy (DOE) Cooperative Agreement DE-FC26-98FT40321 funded through the Office of Fossil Energy and administered at the National Energy Technology Laboratory (NETL) supported the performance of a Jointly Sponsored Research Program (JSRP) at the Energy & Environmental Research Center (EERC) with a minimum 50% nonfederal cost share to assist industry in commercializing and effectively applying highly efficient, nonpolluting energy systems that meet the nation's requirements for clean fuels, chemicals, and electricity in the 21st century. The EERC in partnership with its nonfederal partners jointly performed 131 JSRP projects for which the total DOE cost share was $22,716,634 (38%) and the nonfederal share was $36,776,573 (62%). Summaries of these projects are presented in this report for six program areas: (1) resource characterization and waste management, (2) air quality assessment and control, (3) advanced power systems, (4) advanced fuel forms, (5) value-added coproducts, and (6) advanced materials. The work performed under this agreement addressed DOE goals for reductions in CO{sub 2} emissions through efficiency, capture, and sequestration; near-zero emissions from highly efficient coal-fired power plants; environmental control capabilities for SO{sub 2}, NO{sub x}, fine respirable particulate (PM{sub 2.5}), and mercury; alternative transportation fuels including liquid synfuels and hydrogen; and synergistic integration of fossil and renewable resources.

  4. Use of time-frequency analysis to investigate temporal patterns of cardiac autonomic response during head-up tilt in chronic fatigue syndrome.

    PubMed

    Yoshiuchi, Kazuhiro; Quigley, Karen S; Ohashi, Kyoko; Yamamoto, Yoshiharu; Natelson, Benjamin H

    2004-06-30

    Although a number of studies have reported alterations in cardiac autonomic nervous system function in chronic fatigue syndrome (CFS), the results are not consistent across studies. Reasons for these discrepancies include (1) the use of a heterogeneous patient sample that included those with orthostatic postural tachycardia (POTS), a condition with an autonomic changes, and (2) the use of frequency domain techniques which require a stationary signal and averaging data across relatively long epochs. To deal with these shortcomings, we used the smoothed pseudo-Wigner-Ville transform (SPWVT) to analyze heart rate variability (HRV) and blood pressure variability (BPV) during head-up tilt (HUT) by separating CFS patients into those with and without POTS. SPWVT has the advantage of providing instantaneous information about autonomic function under nonstable physiological conditions. We studied 18 CFS patients without POTS, eight CFS patients with POTS and 25 sedentary healthy controls during supine rest and during the first 10 min after HUT. While we found significant effects of postural change in both groups for all autonomic variables, there were significant group x time interactions between CFS without POTS and controls for only instant center frequency (ICF) within the low frequency region both from HRV (p=0.02) and from BPV (p=0.01). Although the physiological meaning of ICF still remains unknown, the data suggest that even CFS patients without POTS may have a subtle underlying disturbance in autonomic function. PMID:15296795

  5. 20 CFR 410.645 - Joint hearings.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Joint hearings. 410.645 Section 410.645..., Finality of Decisions, and Representation of Parties § 410.645 Joint hearings. When two or more hearings... joint hearing, a joint hearing may not be held. Where joint hearings are held, a single record of...

  6. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Shafting joints. 27.935 Section 27.935... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must...

  7. 37 CFR 1.45 - Joint inventors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Joint inventors. 1.45 Section... Patent § 1.45 Joint inventors. (a) Joint inventors must apply for a patent jointly and each must make the... joint application under 35 U.S.C. 116. If multiple inventors are named in a provisional...

  8. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Shafting joints. 27.935 Section 27.935... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must...

  9. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Shafting joints. 29.935 Section 29.935... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation...

  10. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Rail joints. 213.121 Section 213.121..., DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions...

  11. 37 CFR 1.45 - Joint inventors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Joint inventors. 1.45 Section... Patent § 1.45 Joint inventors. (a) Joint inventors must apply for a patent jointly and each must make the... joint application under 35 U.S.C. 116. If multiple inventors are named in a provisional...

  12. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Rail joints. 213.121 Section 213.121..., DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions...

  13. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture... PLANT VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by signing as joint applicants. (b) If an application for certificate is made by...

  14. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Rail joints. 213.121 Section 213.121..., DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions...

  15. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture... PLANT VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by signing as joint applicants. (b) If an application for certificate is made by...

  16. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Shafting joints. 27.935 Section 27.935... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must...

  17. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Shafting joints. 29.935 Section 29.935... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation...

  18. 20 CFR 410.645 - Joint hearings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Joint hearings. 410.645 Section 410.645..., Finality of Decisions, and Representation of Parties § 410.645 Joint hearings. When two or more hearings... joint hearing, a joint hearing may not be held. Where joint hearings are held, a single record of...

  19. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Rail joints. 213.121 Section 213.121..., DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions...

  20. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Shafting joints. 29.935 Section 29.935... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation...

  1. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Shafting joints. 27.935 Section 27.935... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must...

  2. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture... PLANT VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by signing as joint applicants. (b) If an application for certificate is made by...

  3. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture... PLANT VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by signing as joint applicants. (b) If an application for certificate is made by...

  4. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Shafting joints. 29.935 Section 29.935... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation...

  5. Visualizing Knowledge Domains.

    ERIC Educational Resources Information Center

    Borner, Katy; Chen, Chaomei; Boyack, Kevin W.

    2003-01-01

    Reviews visualization techniques for scientific disciplines and information retrieval and classification. Highlights include historical background of scientometrics, bibliometrics, and citation analysis; map generation; process flow of visualizing knowledge domains; measures and similarity calculations; vector space model; factor analysis;…

  6. Domain wall Skyrmions

    E-print Network

    Gudnason, Sven Bjarke

    2014-01-01

    Skyrmions of different dimensions are related by domain walls. We obtain explicit full numerical solutions of various Skyrmion configurations trapped inside a domain wall. We find for the quadratic mass-term that multi-Skyrmions are ring-shaped, and conjecture for the linear mass-term, that the lowest-energy state of multi-Skyrmions will consist of charge-2 rings accommodated in a lattice.

  7. Localization on Snowflake Domains

    E-print Network

    Britta Daudert; Michel L. Lapidus

    2006-09-28

    The geometric features of the square and triadic Koch snowflake drums are compared using a position entropy defined on the grid points of the discretizations (pre-fractals) of the two domains. Weighted graphs using the geometric quantities are created and random walks on the two pre-fractals are performed. The aim is to understand if the existence of narrow channels in the domain may cause the `localization' of eigenfunctions.

  8. Extending Protein Domain Boundary Predictors to Detect Discontinuous Domains

    PubMed Central

    Xue, Zhidong; Jang, Richard; Govindarajoo, Brandon; Huang, Yichu; Wang, Yan

    2015-01-01

    A variety of protein domain predictors were developed to predict protein domain boundaries in recent years, but most of them cannot predict discontinuous domains. Considering nearly 40% of multidomain proteins contain one or more discontinuous domains, we have developed DomEx to enable domain boundary predictors to detect discontinuous domains by assembling the continuous domain segments. Discontinuous domains are predicted by matching the sequence profile of concatenated continuous domain segments with the profiles from a single-domain library derived from SCOP and CATH, and Pfam. Then the matches are filtered by similarity to library templates, a symmetric index score and a profile-profile alignment score. DomEx recalled 32.3% discontinuous domains with 86.5% precision when tested on 97 non-homologous protein chains containing 58 continuous and 99 discontinuous domains, in which the predicted domain segments are within ±20 residues of the boundary definitions in CATH 3.5. Compared with our recently developed predictor, ThreaDom, which is the state-of-the-art tool to detect discontinuous-domains, DomEx recalled 26.7% discontinuous domains with 72.7% precision in a benchmark with 29 discontinuous-domain chains, where ThreaDom failed to predict any discontinuous domains. Furthermore, combined with ThreaDom, the method ranked number one among 10 predictors. The source code and datasets are available at https://github.com/xuezhidong/DomEx. PMID:26502173

  9. Joint strength in RCS frames 

    E-print Network

    Kirby, Cynthia Dawn

    1998-01-01

    for the addition of a RC slab, cover plates, and band plates. Results indicated that the addition of a reinforced concrete slab compositely connected to the steel beams framing into a typical RCS joints as defined by the ASCE guidelines (1994), improved the joint...

  10. Exercise and the Knee Joint.

    ERIC Educational Resources Information Center

    Clarke, H. Harrison, Ed.

    1976-01-01

    This report by the President's Council on Physical Fitness and Sports examines the effects of various forms of physical exercise on the knee joint which, because of its vulnerability, is especially subject to injury. Discussion centers around the physical characteristics of the joint, commonly used measurements for determining knee stability,…

  11. Tube joint leak repair coupling

    NASA Technical Reports Server (NTRS)

    Ferguson, W. B.

    1968-01-01

    Tube joint leak repair coupling consists of 2 split seals, 1 male split nut, 1 female split nut, and two aligning pins. Each split nut consists of 2 half-shell sections which, when engaged, are held together by a dovetail joint and an aligning pin.

  12. Corynebacterium Prosthetic Joint Infection

    PubMed Central

    Cazanave, Charles; Greenwood-Quaintance, Kerryl E.; Hanssen, Arlen D.

    2012-01-01

    Identification of Corynebacterium species may be challenging. Corynebacterium species are occasional causes of prosthetic joint infection (PJI), but few data are available on the subject. Based on the literature, C. amycolatum, C. aurimucosum, C. jeikeium, and C. striatum are the most common Corynebacterium species that cause PJI. We designed a rapid PCR assay to detect the most common human Corynebacterium species, with a specific focus on PJI. A polyphosphate kinase gene identified using whole-genome sequence was targeted. The assay differentiates the antibiotic-resistant species C. jeikeium and C. urealyticum from other species in a single assay. The assay was applied to a collection of human Corynebacterium isolates from multiple clinical sources, and clinically relevant species were detected. The assay was then tested on Corynebacterium isolates specifically associated with PJI; all were detected. We also describe the first case of C. simulans PJI. PMID:22337986

  13. Arthritis at the shoulder joint.

    PubMed

    Sankaye, Prashant; Ostlere, Simon

    2015-07-01

    The shoulder is a complex joint with numerous structures contributing to mobility and stability. Shoulder pain is a common clinical complaint that may be due to a wide spectrum of disorders including rotator cuff disease, instability, and arthropathy. Primary osteoarthritis of the shoulder joint is uncommon because it is a non-weight-bearing joint. Significant osteoarthritis of the glenohumeral joint is unusual in the absence of trauma, and the detection of advanced degenerative changes in patients without a known history of trauma should alert the clinician to search for other disorders. This article reviews the pathogenesis, clinical manifestations, and key imaging findings of the common categories of the arthritis affecting the glenohumeral joint. PMID:26021591

  14. Shock transmissibility of threaded joints

    SciTech Connect

    Hansen, N.R.; Bateman, V.I.; Brown, F.A.

    1996-12-31

    Sandia National Laboratories (SNL) designs mechanical systems with threaded joints that must survive high shock environments. These mechanical systems include penetrators that must survive soil and rock penetration; drilling pipe strings that must survive rock-cutting, shock environments; and laydown weapons that must survive delivery impact shock. This paper summarizes an analytical study and an experimental evaluation of compressive, one-dimensional, shock transmission through a threaded joint in a split Hopkinson bar configuration. Thread geometries were scaled to simulate large diameter threaded joints with loadings parallel to the axis of the threads. Both strain and acceleration were evaluated with experimental measurements and analysis. Analytical results confirm the experimental conclusions that in this split Hopkinson bar configuration, the change in the one-dimensional shock wave by the threaded joint is localized to a length equal to a few diameters` length beyond the threaded joint.

  15. Space Station alpha joint bearing

    NASA Technical Reports Server (NTRS)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  16. Method of forming a joint

    DOEpatents

    Butt, Darryl Paul; Cutler, Raymond Ashton; Rynders, Steven Walton; Carolan, Michael Francis

    2006-08-22

    A method of joining at least two sintered bodies to form a composite structure, including providing a first multicomponent metallic oxide having a perovskitic or fluorite crystal structure; providing a second sintered body including a second multicomponent metallic oxide having a crystal structure of the same type as the first; and providing at an interface a joint material containing at least one metal oxide containing at least one metal identically contained in at least one of the first and second multicomponent metallic oxides. The joint material is free of cations of Si, Ge, Sn, Pb, P and Te and has a melting point below the sintering temperatures of both sintered bodies. The joint material is heated to a temperature above the melting point of the metal oxide(s) and below the sintering temperatures of the sintered bodies to form the joint. Structures containing such joints are also disclosed.

  17. Domains in Ferroelectric Nanostructures

    NASA Astrophysics Data System (ADS)

    Gregg, Marty

    2010-03-01

    Ferroelectric materials have great potential in influencing the future of small scale electronics. At a basic level, this is because ferroelectric surfaces are charged, and so interact strongly with charge-carrying metals and semiconductors - the building blocks for all electronic systems. Since the electrical polarity of the ferroelectric can be reversed, surfaces can both attract and repel charges in nearby materials, and can thereby exert complete control over both charge distribution and movement. It should be no surprise, therefore, that microelectronics industries have already looked very seriously at harnessing ferroelectric materials in a variety of applications, from solid state memory chips (FeRAMs) to field effect transistors (FeFETs). In all such applications, switching the direction of the polarity of the ferroelectric is a key aspect of functional behavior. The mechanism for switching involves the field-induced nucleation and growth of domains. Domain coarsening, through domain wall propagation, eventually causes the entire ferroelectric to switch its polar direction. It is thus the existence and behavior of domains that determine the switching response, and ultimately the performance of the ferroelectric device. A major issue, associated with the integration of ferroelectrics into microelectronic devices, has been that the fundamental properties associated with ferroelectrics, when in bulk form, appear to change quite dramatically and unpredictably when at the nanoscale: new modes of behaviour, and different functional characteristics from those seen in bulk appear. For domains, in particular, the proximity of surfaces and boundaries have a dramatic effect: surface tension and depolarizing fields both serve to increase the equilibrium density of domains, such that minor changes in scale or morphology can have major ramifications for domain redistribution. Given the importance of domains in dictating the overall switching characteristics of a device, the need to fully understand how size and morphology affect domain behaviour in small scale ferroelectrics is obvious. In this talk, observations from a programme of study examining domains in meso and nano-scale BaTiO3 shapes, that have been cut directly from bulk single crystal using focused ion beam milling, will be presented. In general, the equilibrium static domain configurations that occur appear to be the result of a simultaneous desire to minimize both the macroscopic strain and depolarizing fields developed on cooling through the Curie Temperature. While such governing factors might be obvious, the specific patterns that result as a function of morphology are often non-intuitive, and a series of images of domains in nanodots, rods and wires will be presented and rationalised. In addition, the nature in which morphological factors influence domain dynamics during switching will be discussed, with particular focus on axial switching in nanowires, and the manner in which local surface perturbations (such as notches and antinotches) affect domain wall propagation. In collaboration with Alina Schilling, Li-Wu Chang, Mark McMillen, Raymond McQuaid, and Leo McGilly, Queen's University Belfast; Gustau Catalan, Universitat Autonoma de Barcelona; and James Scott, University of Cambridge.

  18. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Joint employment. 791.2 Section 791...INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single...

  19. 11 CFR 9034.8 - Joint fundraising.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Joint fundraising. 9034.8 Section 9034...MATCHING FUND ENTITLEMENTS § 9034.8 Joint fundraising. (a) General...funds under this subchapter may engage in joint fundraising with other candidates,...

  20. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Joint employment. 791.2 Section 791...INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single...

  1. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Joint employment. 791.2 Section 791...INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single...

  2. 11 CFR 9034.8 - Joint fundraising.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Joint fundraising. 9034.8 Section 9034...MATCHING FUND ENTITLEMENTS § 9034.8 Joint fundraising. (a) General...funds under this subchapter may engage in joint fundraising with other candidates,...

  3. 24 CFR 570.308 - Joint requests.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Development 3 2013-04-01 2013-04-01 false Joint requests. 570.308 Section 570.308 Housing...BLOCK GRANTS Entitlement Grants § 570.308 Joint requests. (a) Joint requests and cooperation agreements....

  4. 11 CFR 9034.8 - Joint fundraising.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Joint fundraising. 9034.8 Section 9034...MATCHING FUND ENTITLEMENTS § 9034.8 Joint fundraising. (a) General...funds under this subchapter may engage in joint fundraising with other candidates,...

  5. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Joint employment. 791.2 Section 791...INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single...

  6. 24 CFR 570.308 - Joint requests.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Development 3 2014-04-01 2013-04-01 true Joint requests. 570.308 Section 570.308 Housing...BLOCK GRANTS Entitlement Grants § 570.308 Joint requests. (a) Joint requests and cooperation agreements....

  7. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Joint employment. 791.2 Section 791...INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single...

  8. 11 CFR 9034.8 - Joint fundraising.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Joint fundraising. 9034.8 Section 9034...MATCHING FUND ENTITLEMENTS § 9034.8 Joint fundraising. (a) General...funds under this subchapter may engage in joint fundraising with other candidates,...

  9. 11 CFR 9034.8 - Joint fundraising.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2012-01-01 true Joint fundraising. 9034.8 Section 9034...MATCHING FUND ENTITLEMENTS § 9034.8 Joint fundraising. (a) General...funds under this subchapter may engage in joint fundraising with other candidates,...

  10. 24 CFR 570.308 - Joint requests.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...Development 3 2012-04-01 2012-04-01 false Joint requests. 570.308 Section 570.308 Housing...BLOCK GRANTS Entitlement Grants § 570.308 Joint requests. (a) Joint requests and cooperation agreements....

  11. Common Bolted Joint Analysis Tool

    NASA Technical Reports Server (NTRS)

    Imtiaz, Kauser

    2011-01-01

    Common Bolted Joint Analysis Tool (comBAT) is an Excel/VB-based bolted joint analysis/optimization program that lays out a systematic foundation for an inexperienced or seasoned analyst to determine fastener size, material, and assembly torque for a given design. Analysts are able to perform numerous what-if scenarios within minutes to arrive at an optimal solution. The program evaluates input design parameters, performs joint assembly checks, and steps through numerous calculations to arrive at several key margins of safety for each member in a joint. It also checks for joint gapping, provides fatigue calculations, and generates joint diagrams for a visual reference. Optimum fastener size and material, as well as correct torque, can then be provided. Analysis methodology, equations, and guidelines are provided throughout the solution sequence so that this program does not become a "black box:" for the analyst. There are built-in databases that reduce the legwork required by the analyst. Each step is clearly identified and results are provided in number format, as well as color-coded spelled-out words to draw user attention. The three key features of the software are robust technical content, innovative and user friendly I/O, and a large database. The program addresses every aspect of bolted joint analysis and proves to be an instructional tool at the same time. It saves analysis time, has intelligent messaging features, and catches operator errors in real time.

  12. Qualification of improved joint heaters

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    Qualification testing of the Redesigned Solid Rocket Motor improved igniter-to-case joint and field joint heaters was conducted on the fired TEM-04 static test motor and was completed on 7 Sep. 1989. The purpose of the test was to certify the installation and performance of the improved joint heaters for use on flight motors. The changes incorporated in the improved heaters improve durability and should reduce handling damage. The igniter-to-case joint and field joint primary heater circuits were subjected to five 20-hr ON cycles. The heater redundant circuits were then subjected to one 20-hr ON cycle. Voltage, current, and temperature set point values were maintained within the specified limits for both heaters during each ON cycle. When testing was complete, both heaters were removed and inspected. No discolorations or any other anomalies were found on either of the heaters. Based on the successful completion of this test, it is recommended that the improved igniter-to-case joint and field joint heaters be used on future flight motors.

  13. The PDV Velocity History and Shock Arrival Time Analyzer

    Energy Science and Technology Software Center (ESTSC)

    2006-08-29

    This software allows the user to analyze heterodyne beat signals generated when a Doppler-shifted laser light interacts with un-shifted laser light. The software analyzes the data in a joint time frequency domain to extract instantaneous velocity.

  14. Axion domain wall baryogenesis

    NASA Astrophysics Data System (ADS)

    Daido, Ryuji; Kitajima, Naoya; Takahashi, Fuminobu

    2015-07-01

    We propose a new scenario of baryogenesis, in which annihilation of axion domain walls generates a sizable baryon asymmetry. Successful baryogenesis is possible for a wide range of the axion mass and decay constant, m simeq 108–1013 GeV and f simeq 1013–1016 GeV . Baryonic isocurvature perturbations are significantly suppressed in our model, in contrast to various spontaneous baryogenesis scenarios in the slow-roll regime. In particular, the axion domain wall baryogenesis is consistent with high-scale inflation which generates a large tensor-to-scalar ratio within the reach of future CMB B-mode experiments. We also discuss the gravitational waves produced by the domain wall annihilation and its implications for the future gravitational wave experiments.

  15. Atomic Pseudo-Valuation Domains

    E-print Network

    Stines, Elijah

    2012-01-01

    Pseudo-valuation domains have been studied since their introduction in 1978 by Hedstrom and Houston. Related objects, boundary valuation domains, were introduced by Maney in 2004. Here, it is shown that the class of atomic pseudo-valuation domains coincides with the class of boundary valuation domains. It is also shown that power series rings and generalized power series rings give examples of pseudo-valuation domains whose congruence lattices can be characterized. The paper also introduces, and makes use of, a sufficient condition on the group of divisibility of a domain to guarantee that it is a pseudo-valuation domain.

  16. Joint numerical ranges, quantum maps, and joint numerical shadows

    E-print Network

    Eugene Gutkin; Karol Zyczkowski

    2012-10-12

    We associate with k hermitian N\\times N matrices a probability measure on R^k. It is supported on the joint numerical range of the k-tuple of matrices. We call this measure the joint numerical shadow of these matrices. Let k=2. A pair of hermitian N\\times N matrices defines a complex N\\times N matrix. The joint numerical range and the joint numerical shadow of the pair of hermitian matrices coincide with the numerical range and the numerical shadow, respectively, of this complex matrix. We study relationships between the dynamics of quantum maps on the set of quantum states, on one hand, and the numerical ranges, on the other hand. In particular, we show that under the identity resolution assumption on Kraus operators defining the quantum map, the dynamics shrinks numerical ranges.

  17. Optimal domain decomposition strategies

    NASA Technical Reports Server (NTRS)

    Yoon, Yonghyun; Soni, Bharat K.

    1995-01-01

    The primary interest of the authors is in the area of grid generation, in particular, optimal domain decomposition about realistic configurations. A grid generation procedure with optimal blocking strategies has been developed to generate multi-block grids for a circular-to-rectangular transition duct. The focus of this study is the domain decomposition which optimizes solution algorithm/block compatibility based on geometrical complexities as well as the physical characteristics of flow field. The progress realized in this study is summarized in this paper.

  18. Compliant Prosthetic Or Robotic Joint

    NASA Technical Reports Server (NTRS)

    Kerley, James J.; Eklund, Wayne D.

    1989-01-01

    Rotation partly free and partly restrained by resilience and damping. Joint includes U-shaped x- and y-axis frames joined by cables that cross in at center piece. The y-axis frame rotates about y-axis on roller bearing within predetermined angular range. The y-axis frame rotates slightly farther when arm strikes stop, because cables can twist. This mimics compliant resistance of knee joint reaching limit of its forward or backward motion. Used in prosthetic device to replace diseased or damage human joint, or in robot linkage to limit movement and cushion overloads.

  19. Blur-resistant joint 1D and 2D barcode localization for smartphones

    E-print Network

    Blur-resistant joint 1D and 2D barcode localization for smartphones Gábor Sörös Institute@inf.ethz.ch ABSTRACT With the proliferation of built-in cameras barcode scanning on smartphones has become widespread in both consumer and enterprise domains. To avoid making the user precisely align the barcode

  20. Acromioclavicular joint cyst formation.

    PubMed

    Hiller, Andrew D; Miller, Joshua D; Zeller, John L

    2010-03-01

    Acromioclavicular joint (ACJ) cysts are an uncommon and unusual sequela associated with shoulder pathophysiology. The majority of literature on ACJ cysts consists of individual case reports with no definitive literature review currently available. In addition to a comprehensive literature review, four clinical cases are presented in this report. First described by Craig (1984), a total of 41 cases have been previously reported in the literature. Of these cases, five occurred with the rotator cuff musculature intact. The remaining 36 cases of ACJ cysts occurred in patients with a complete tear/avulsion of the rotator cuff. Previous attempts at compiling a complete record of all reported cases have combined several distinct conditions into a single category. This article presents two distinct etiologies for the pathogenesis of ACJ cyst formation. In the presence of an intact rotator cuff, a Type 1 cyst can form superficially and be limited to the ACJ. Following a massive or traumatic tear of the rotator cuff, mechanical instability of the humeral head can cause a deterioration of the inferior acromioclavicular capsule (cuff tear arthropathy) and an overproduction of synovial fluid. Overtime, a "geyser" of fluid can form between the glenohumeral and the ACJ, forming a Type 2 cyst. This differentiation and categorization is essential for appropriate classification and treatment. PMID:20069645

  1. Characteristics of temporomandibular joint in patients with temporomandibular joint complaint

    PubMed Central

    Li, Yanfeng; Guo, Xiaoqian; Sun, Xiaoxue; Wang, Ning; Xie, Min; Zhang, Jianqiang; Lv, Yuan; Han, Weili; Hu, Min; Liu, Hongchen

    2015-01-01

    Introduction: This study was to investigate whether there was statistical difference between the bilateral temporomandibular joint (TMJ) in patients with unilateral TMJ pain or joint sounds, using cone beam computed tomography (CBCT). Methods: TMJ CBCT images of 123 cases were used to preliminarily determine the indicators suitable for the measuring method. TMJ CBCT image reconstruction was performed and 19 indicators were measured. Thirty-six cases without TMJ complaint served as controls. The comparison of bilateral TMJs was analyzed by paired t-test to find out the indicators without statistical significance. Twenty-nine patients with unilateral TMJ pain or joint sounds who underwent CBCT at the hospital were enrolled for the comparative study. The measured values were analyzed by paired t-test to determine the indicators with statistical difference. Results: In the control group, only radius value of bilateral TMJ was different statistically (P < 0.05). In the TMJ complaint group, the vertical 60° joint space of the bilateral TMJ was statistically different (P < 0.05) and the rest of the measured values showed no statistical difference. Conclusions: In the patients with unilateral TMJ pain or joint sounds, the vertical 60° joint space of the symptomatic side was significantly increased comparing with the asymptomatic side. PMID:26629112

  2. The Application of Auto-Disturbance Rejection Control Optimized by Least Squares Support Vector Machines Method and Time-Frequency Representation in Voltage Source Converter-High Voltage Direct Current System

    PubMed Central

    Gao, Zhong-Ke

    2015-01-01

    In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane. PMID:26098556

  3. Time-domain imaging

    NASA Technical Reports Server (NTRS)

    Tolliver, C. L.

    1989-01-01

    The quest for the highest resolution microwave imaging and principle of time-domain imaging has been the primary motivation for recent developments in time-domain techniques. With the present technology, fast time varying signals can now be measured and recorded both in magnitude and in-phase. It has also enhanced our ability to extract relevant details concerning the scattering object. In the past, the interface of object geometry or shape for scattered signals has received substantial attention in radar technology. Various scattering theories were proposed to develop analytical solutions to this problem. Furthermore, the random inversion, frequency swept holography, and the synthetic radar imaging, have two things in common: (1) the physical optic far-field approximation, and (2) the utilization of channels as an extra physical dimension, were also advanced. Despite the inherent vectorial nature of electromagnetic waves, these scalar treatments have brought forth some promising results in practice with notable examples in subsurface and structure sounding. The development of time-domain techniques are studied through the theoretical aspects as well as experimental verification. The use of time-domain imaging for space robotic vision applications has been suggested.

  4. Cellulose binding domain proteins

    DOEpatents

    Shoseyov, O.; Shpiegl, I.; Goldstein, M.; Doi, R.

    1998-11-17

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 16 figs.

  5. Domain walls - horizontal epilogue

    NASA Astrophysics Data System (ADS)

    Davidson, Aharon; Vozmediano, A. H.

    1984-06-01

    A horizontal realization of the Peccei-Quinn symmetry together with the presence of B (or B - L) global invariance allow us to solve the domain wall problem without the need for exotic fermions or extra gauge interactions. The intergenerational Yukawa structure dictated by the connectness of the manifold of degenerate vacuum states is analysed.

  6. Cellulose binding domain proteins

    DOEpatents

    Shoseyov, Oded (Karmey Yosef, IL); Shpiegl, Itai (Rehovot, IL); Goldstein, Marc (Davis, CA); Doi, Roy (Davis, CA)

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  7. Foreign Fishery Developments Japanese Joint

    E-print Network

    .) The four other joint ventures, which are rela- tively small, are located in New Gui- nea, Indonesia, New listed in millions of dollars. Total 25 19 10 26 31 20 60 193 20 Marine Fisheries Review #12;Latin

  8. Osteochondral Lesions of Major Joints

    PubMed Central

    Durur-Subasi, Irmak; Durur-Karakaya, Afak; Yildirim, Omer Selim

    2015-01-01

    This paper provides information about osteochondral lesions (OCL) and example cases of OCL occurring in major joints, some of which are rarely seen. This simple tutorial is presented in question and answer format. PMID:26180500

  9. A JOINT PROGRAM OF Interactive

    E-print Network

    Dawson, Jeff W.

    animation, game design and development, visual effects, graphic design, human-computer interaction (HCIA JOINT PROGRAM OF Interactive Multimedia and Design www.bitdegree.ca BACHELOR OF INFORMATION, imagination, fun and technology. The Interactive Multimedia and Design (IMD) program provides

  10. Joint probabilities and quantum cognition

    E-print Network

    J. Acacio de Barros

    2012-07-03

    In this paper we discuss the existence of joint probability distributions for quantum-like response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

  11. Joint probabilities and quantum cognition

    NASA Astrophysics Data System (ADS)

    de Barros, J. Acacio

    2012-12-01

    In this paper we discuss the existence of joint probability distributions for quantumlike response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

  12. Pyrothermal treatment of welded joints

    SciTech Connect

    Serikov, S.V.; Idiyatullin, R.S.; Myakushkin, S.N.; Yaufman, V.V.

    1992-03-01

    The results of investigation of the structure and distribution of residual stresses in welded joints in pipes after heat treatment, which includes heating of the surface being treated due to combustion of plates formed from a thermite-type material of pyrotechnic composition, placed around the perimeter of the welded joint, and also an assessment of the level of residual stresses prior to and after pyrotechnic treatment demonstrated the promising nature of the proposed method. 5 refs., 5 figs.

  13. IRS memorandum limits joint ventures.

    PubMed

    Herman, A W

    1992-08-01

    Based on a new memorandum, the Internal Revenue Service (IRS) will be looking at joint hospital/physician activities with greater attention to the nuances of public versus private benefit. As a result, hospitals face greater risk of losing their tax-exempt status in the maze of joint ventures, physician recruitment, and practice acquisition. To be successful, ventures will have to be backed by sound reasoning and thorough documentation. PMID:10145664

  14. Unsupervised Spatial Event Detection in Targeted Domains with Applications to Civil Unrest Modeling

    PubMed Central

    Zhao, Liang; Chen, Feng; Dai, Jing; Hua, Ting; Lu, Chang-Tien; Ramakrishnan, Naren

    2014-01-01

    Twitter has become a popular data source as a surrogate for monitoring and detecting events. Targeted domains such as crime, election, and social unrest require the creation of algorithms capable of detecting events pertinent to these domains. Due to the unstructured language, short-length messages, dynamics, and heterogeneity typical of Twitter data streams, it is technically difficult and labor-intensive to develop and maintain supervised learning systems. We present a novel unsupervised approach for detecting spatial events in targeted domains and illustrate this approach using one specific domain, viz. civil unrest modeling. Given a targeted domain, we propose a dynamic query expansion algorithm to iteratively expand domain-related terms, and generate a tweet homogeneous graph. An anomaly identification method is utilized to detect spatial events over this graph by jointly maximizing local modularity and spatial scan statistics. Extensive experiments conducted in 10 Latin American countries demonstrate the effectiveness of the proposed approach. PMID:25350136

  15. Simplified procedures for designing composite bolted joints

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    1988-01-01

    Simplified procedures are described to design and analyze single and multi-bolt composite joints. Numerical examples illustrate the use of these methods. Factors affecting composite bolted joints are summarized. References are cited where more detailed discussion is presented on specific aspects of composite bolted joints. Design variables associated with these joints are summarized in the appendix.

  16. 21 CFR 26.73 - Joint Committee.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Joint Committee. 26.73 Section 26.73 Food and...Frameworkâ Provisions § 26.73 Joint Committee. (a) A Joint Committee consisting of representatives of the United States and the European Community (EC) will be established. The Joint Committee shall...

  17. 42 CFR 422.1040 - Joint hearings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Joint hearings. 422.1040 Section 422.1040 Public...) MEDICARE PROGRAM MEDICARE ADVANTAGE PROGRAM Appeal procedures for Civil Money Penalties § 422.1040 Joint... conference or hearing and conduct all proceedings jointly. If joint hearings are held, a single record of...

  18. 12 CFR 347.107 - Joint ventures.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 4 2011-01-01 2011-01-01 false Joint ventures. 347.107 Section 347.107 Banks... INTERNATIONAL BANKING § 347.107 Joint ventures. (a) Joint ventures. If a bank, directly or indirectly, acquires or holds an equity interest in a foreign organization that is a joint venture, and the bank or...

  19. 32 CFR 536.54 - Joint tortfeasors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 3 2011-07-01 2009-07-01 true Joint tortfeasors. 536.54 Section 536.54 National... UNITED STATES Investigation and Processing of Claims § 536.54 Joint tortfeasors. When joint tortfeasors... United States rather than pay the claim in full and then bring suit against the joint tortfeasor...

  20. 42 CFR 423.1040 - Joint hearings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Joint hearings. 423.1040 Section 423.1040 Public... § 423.1040 Joint hearings. When two or more affected parties have requested hearings and the same or... the prehearing conference or hearing and conduct all proceedings jointly. If joint hearings are...

  1. Joint Press Release TWELFTH ITER NEGOTIATION MEETING

    E-print Network

    Joint Press Release TWELFTH ITER NEGOTIATION MEETING Jeju, Korea, 6 December th 2005 Delegations on an Agreement on the joint implementation of the ITER international fusion energy project. This was the first/6/05 1:21 PMDraft Joint News Release Page 1 of 2http://www.iter.org/N_12_Joint_Press_Release.htm #12

  2. 42 CFR 423.1040 - Joint hearings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Joint hearings. 423.1040 Section 423.1040 Public... § 423.1040 Joint hearings. When two or more affected parties have requested hearings and the same or... the prehearing conference or hearing and conduct all proceedings jointly. If joint hearings are...

  3. 49 CFR 234.233 - Rail joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Rail joints. 234.233 Section 234.233..., Inspection, and Testing Maintenance Standards § 234.233 Rail joints. Each non-insulated rail joint located... than joint bars and the bonds shall be maintained in such condition to ensure electrical conductivity....

  4. 47 CFR 76.912 - Joint certification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Joint certification. 76.912 Section 76.912... CABLE TELEVISION SERVICE Cable Rate Regulation § 76.912 Joint certification. (a) Franchising authorities may apply for joint certification and may engage in joint regulation, including, but not limited...

  5. 47 CFR 76.912 - Joint certification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Joint certification. 76.912 Section 76.912... CABLE TELEVISION SERVICE Cable Rate Regulation § 76.912 Joint certification. (a) Franchising authorities may apply for joint certification and may engage in joint regulation, including, but not limited...

  6. 21 CFR 26.73 - Joint Committee.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Joint Committee. 26.73 Section 26.73 Food and...Frameworkâ Provisions § 26.73 Joint Committee. (a) A Joint Committee consisting of representatives of the United States and the European Community (EC) will be established. The Joint Committee shall...

  7. 32 CFR 536.54 - Joint tortfeasors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 3 2013-07-01 2013-07-01 false Joint tortfeasors. 536.54 Section 536.54... AGAINST THE UNITED STATES Investigation and Processing of Claims § 536.54 Joint tortfeasors. When joint... United States rather than pay the claim in full and then bring suit against the joint tortfeasor...

  8. 14 CFR 23.693 - Joints.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Joints. 23.693 Section 23.693 Aeronautics... Systems § 23.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion... factor may be reduced to 2.0 for joints in cable control systems. For ball or roller bearings,...

  9. 14 CFR 23.693 - Joints.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Joints. 23.693 Section 23.693 Aeronautics... Systems § 23.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion... factor may be reduced to 2.0 for joints in cable control systems. For ball or roller bearings,...

  10. 49 CFR 234.233 - Rail joints.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Rail joints. 234.233 Section 234.233..., Inspection, and Testing Maintenance Standards § 234.233 Rail joints. Each non-insulated rail joint located... than joint bars and the bonds shall be maintained in such condition to ensure electrical conductivity....

  11. 38 CFR 4.45 - The joints.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false The joints. 4.45 Section... DISABILITIES Disability Ratings The Musculoskeletal System § 4.45 The joints. As regards the joints the factors... (from flail joint, resections, nonunion of fracture, relaxation of ligaments, etc.). (c)...

  12. 21 CFR 26.73 - Joint Committee.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Joint Committee. 26.73 Section 26.73 Food and...Frameworkâ Provisions § 26.73 Joint Committee. (a) A Joint Committee consisting of representatives of the United States and the European Community (EC) will be established. The Joint Committee shall...

  13. 42 CFR 422.1040 - Joint hearings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 3 2013-10-01 2013-10-01 false Joint hearings. 422.1040 Section 422.1040 Public....1040 Joint hearings. When two or more affected parties have requested hearings and the same or... the prehearing conference or hearing and conduct all proceedings jointly. If joint hearings are...

  14. 21 CFR 26.73 - Joint Committee.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Joint Committee. 26.73 Section 26.73 Food and...Frameworkâ Provisions § 26.73 Joint Committee. (a) A Joint Committee consisting of representatives of the United States and the European Community (EC) will be established. The Joint Committee shall...

  15. 47 CFR 76.912 - Joint certification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Joint certification. 76.912 Section 76.912... CABLE TELEVISION SERVICE Cable Rate Regulation § 76.912 Joint certification. (a) Franchising authorities may apply for joint certification and may engage in joint regulation, including, but not limited...

  16. 32 CFR 536.54 - Joint tortfeasors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Joint tortfeasors. 536.54 Section 536.54 National... UNITED STATES Investigation and Processing of Claims § 536.54 Joint tortfeasors. When joint tortfeasors... United States rather than pay the claim in full and then bring suit against the joint tortfeasor...

  17. Joint Random Variables and their Distributions

    E-print Network

    Stewart, William J.

    Chapter 4 Joint Random Variables and their Distributions We now move on to consider probability. We begin by defining the joint probability mass function of two discrete random variables. 4.1 Joint Probability Mass Functions Whereas a single random variable maps outcomes into points on the real line, joint

  18. 38 CFR 4.45 - The joints.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false The joints. 4.45 Section... DISABILITIES Disability Ratings The Musculoskeletal System § 4.45 The joints. As regards the joints the factors... (from flail joint, resections, nonunion of fracture, relaxation of ligaments, etc.). (c)...

  19. 14 CFR 23.693 - Joints.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Joints. 23.693 Section 23.693 Aeronautics... Systems § 23.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion... factor may be reduced to 2.0 for joints in cable control systems. For ball or roller bearings,...

  20. 14 CFR 23.693 - Joints.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Joints. 23.693 Section 23.693 Aeronautics... Systems § 23.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion... factor may be reduced to 2.0 for joints in cable control systems. For ball or roller bearings,...

  1. 42 CFR 422.1040 - Joint hearings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Joint hearings. 422.1040 Section 422.1040 Public...) MEDICARE PROGRAM MEDICARE ADVANTAGE PROGRAM Appeal procedures for Civil Money Penalties § 422.1040 Joint... conference or hearing and conduct all proceedings jointly. If joint hearings are held, a single record of...

  2. 49 CFR 234.233 - Rail joints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Rail joints. 234.233 Section 234.233... joints. Each non-insulated rail joint located within the limits of a highway-rail grade crossing train detection circuit shall be bonded by means other than joint bars and the bonds shall be maintained in...

  3. 12 CFR 347.107 - Joint ventures.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Joint ventures. 347.107 Section 347.107 Banks... INTERNATIONAL BANKING § 347.107 Joint ventures. (a) Joint ventures. If a bank, directly or indirectly, acquires or holds an equity interest in a foreign organization that is a joint venture, and the bank or...

  4. 47 CFR 76.912 - Joint certification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Joint certification. 76.912 Section 76.912... CABLE TELEVISION SERVICE Cable Rate Regulation § 76.912 Joint certification. (a) Franchising authorities may apply for joint certification and may engage in joint regulation, including, but not limited...

  5. 42 CFR 422.1040 - Joint hearings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 3 2014-10-01 2014-10-01 false Joint hearings. 422.1040 Section 422.1040 Public....1040 Joint hearings. When two or more affected parties have requested hearings and the same or... the prehearing conference or hearing and conduct all proceedings jointly. If joint hearings are...

  6. 12 CFR 347.107 - Joint ventures.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Joint ventures. 347.107 Section 347.107 Banks... INTERNATIONAL BANKING § 347.107 Joint ventures. (a) Joint ventures. If a bank, directly or indirectly, acquires or holds an equity interest in a foreign organization that is a joint venture, and the bank or...

  7. 49 CFR 234.233 - Rail joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Rail joints. 234.233 Section 234.233... joints. Each non-insulated rail joint located within the limits of a highway-rail grade crossing train detection circuit shall be bonded by means other than joint bars and the bonds shall be maintained in...

  8. 32 CFR 536.54 - Joint tortfeasors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 3 2014-07-01 2014-07-01 false Joint tortfeasors. 536.54 Section 536.54... AGAINST THE UNITED STATES Investigation and Processing of Claims § 536.54 Joint tortfeasors. When joint... United States rather than pay the claim in full and then bring suit against the joint tortfeasor...

  9. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Agriculture 3 2011-01-01 2011-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture...VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by...

  10. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Agriculture 3 2012-01-01 2012-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture...VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by...

  11. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...Agriculture 3 2013-01-01 2013-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture...VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by...

  12. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Agriculture 3 2014-01-01 2014-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture...VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by...

  13. Young Children's Understanding of Joint Commitments

    ERIC Educational Resources Information Center

    Grafenhain, Maria; Behne, Tanya; Carpenter, Malinda; Tomasello, Michael

    2009-01-01

    When adults make a joint commitment to act together, they feel an obligation to their partner. In 2 studies, the authors investigated whether young children also understand joint commitments to act together. In the first study, when an adult orchestrated with the child a joint commitment to play a game together and then broke off from their joint

  14. Functional motion simulation of the hip joint

    E-print Network

    Bartz, Dirk

    1 Functional motion simulation of the hip joint Prof. Nadia Magnenat-Thalmann MIRALab University of the hip joint Approach: Acetabular rim syndrom · Early diagnostic of abnormal impingements · Surgery of the hip joint Clinical objective Tutorial 6Eurographics 2004 Functional motion simulation of the hip joint

  15. Error analysis in frequency domain for fiber optic gyro attitude reference and control system

    NASA Astrophysics Data System (ADS)

    Wu, Wenqi; Zhu, Libin; Jiang, Mingming; Tuo, Zhouhui

    2003-09-01

    A shipboard attitude reference and control system using fiber optic gyros is analyzed. In this system, the frequency character of the attitude error is more concerned, because high frequency attitude measuring errors can some times cause vibration in control system. In this paper, system kinematic model using quaternion is addressed and stabilization analysis based on Lyapunov theory is presented. By time-frequency distribution analysis, it is pointed out that the key problem is how to confine the high frequency body attitude errors and angular velocity errors measured by the fiber optic gyros. Lowpass filter is imposed to solve this problem. In this way, while the high frequency attitude vibrations are restrained, the body attitude error would become larger. Frequency domain confinement and time domain confinement to the system errors should be balanced in practical engineering.

  16. A Multivariate Technique for Evaluating the Statistical Homogeneity of Jointed Rock Masses

    NASA Astrophysics Data System (ADS)

    Li, Yanyan; Wang, Qing; Chen, Jianping; Song, Shengyuan; Ruan, Yunkai; Zhang, Qi

    2015-09-01

    Various approaches have been developed for identifying statistically homogeneous regions or structural domains in a jointed rock mass based on joint orientations or the other joint parameters; however, few studies have been conducted by integrating both. In this paper, nine parameters are considered for this identification, namely: orientation, spacing, aperture, roughness, trace length, trace type, filling, groundwater condition, and weathering. A statistical parameter, known as the correlation coefficient, is used to quantify the degree of the similarity between the joint parameters collected from four adjacent adits at the Songta dam site on the upper reaches of the Nu River in southwest China. Based on the analytic hierarchy process, the weights of the parameters are obtained. The overall homogeneity of the rock mass around the studied regions is determined based on the homogeneity index.

  17. Behavioral Domain Analysis The Application-Based Domain Modeling Approach

    E-print Network

    Reinhartz-Berger, Iris

    (ADOM) approach for domain analysis. This approach treats a domain as a regular application that needs and behavior are modeled, enforcing static and dynamic constraints on the relevant application models. The ADOM, and the application layer consists of domain-specific systems. Furthermore, the ADOM approach defines dependency

  18. Management of acromioclavicular joint injuries.

    PubMed

    Li, Xinning; Ma, Richard; Bedi, Asheesh; Dines, David M; Altchek, David W; Dines, Joshua S

    2014-01-01

    Acromioclavicular joint injuries are among the most common shoulder girdle injuries in athletes and most commonly result from a direct force to the acromion with the arm in an adducted position. Acromioclavicular joint injuries often present with associated injuries to the glenohumeral joint, including an increased incidence of superior labrum anterior posterior (SLAP) tears that may warrant further evaluation and treatment. Anteroposterior stability of the acromioclavicular joint is conferred by the capsule and acromioclavicular ligaments, of which the posterior and superior ligaments are the strongest. Superior-inferior stability is maintained by the coracoclavicular (conoid and trapezoid) ligaments. Type-I or type-II acromioclavicular joint injuries have been treated with sling immobilization, early shoulder motion, and physical therapy, with favorable outcomes. Return to activity can occur when normal shoulder motion and strength are obtained and the shoulder is asymptomatic as compared with the contralateral normal extremity. The management of type-III injuries remains controversial and is individualized. While a return to the previous level of functional activity with nonsurgical treatment has been documented in a number of case series, surgical reduction and coracoclavicular ligament reconstruction has been associated with a favorable outcome and can be considered in patients who place high functional demands on their shoulders or in athletes who participate in overhead sports. Surgical management is indicated for high-grade (?type IV) acromioclavicular joint injuries to achieve anatomic reduction of the acromioclavicular joint, reconstruction of the coracoclavicular ligaments, and repair of the deltotrapezial fascia. Outcomes after surgical reconstruction of the coracoclavicular ligaments have been satisfactory with regard to achieving pain relief and return to functional activities, but further improvements in the biomechanical strength of these constructs are necessary to avoid loss of reduction and creep with cyclic loading. PMID:24382728

  19. An analysis of a joint shear model for jointed media with orthogonal joint sets; Yucca Mountain Site Characterization Project

    SciTech Connect

    Koteras, J.R.

    1991-10-01

    This report describes a joint shear model used in conjunction with a computational model for jointed media with orthogonal joint sets. The joint shear model allows nonlinear behavior for both joint sets. Because nonlinear behavior is allowed for both joint sets, a great many cases must be considered to fully describe the joint shear behavior of the jointed medium. An extensive set of equations is required to describe the joint shear stress and slip displacements that can occur for all the various cases. This report examines possible methods for simplifying this set of equations so that the model can be implemented efficiently form a computational standpoint. The shear model must be examined carefully to obtain a computationally efficient implementation that does not lead to numerical problems. The application to fractures in rock is discussed. 5 refs., 4 figs.

  20. Joint position sense in the normal and pathologic knee joint.

    PubMed

    Skinner, H B; Barrack, R L

    1991-09-01

    Joint position sense has been suggested to be an important factor in the etiology of degenerative joint disease. It is also believed to be important in the rehabilitative process after reconstructive surgery of the knee. Despite this awareness, in many areas of orthopaedic surgery little effort has been devoted to study of this crucial topic. Therefore, we conducted several studies of knee joint position sense by measuring the ability of healthy subjects to reproduce an angle and detect the threshold of motion. Our goal was to evaluate the effects of the following factors: aging; degenerative joint disease; total knee replacement, i.e., both absence of the anterior cruciate ligament (ACL) and sensory loss due to the absence of capsular structures; fatigue; athletic training; disruption and reconstruction of the ACL; and the role of ligament mechanoreceptors. Our results show that normal individuals can actively reproduce an angle with their knee to an average error of 2.5°. Furthermore, normal subjects require passive movement of ?2.5°-4° to detect a change in position at the speeds used in this study (?0.5°/s). Muscular training improves the ability to detect motion. On the other hand, muscular training and fatigue appear to decrease the ability to reproduce an angle. Changes in the knee and its associated structures caused by damage (ACL disruption, arthritis, total knee replacement) as well as aging uniformly cause deterioration of joint position sense. Total knee replacement and arthritic change cause the greatest deterioration. Reconstruction of ligamentous structures and/or rehabilitation appears to restore joint position sense to a near normal level. PMID:20870508

  1. Unsharp measurements and joint measurability

    E-print Network

    H. S. Karthik; A. R. Usha Devi; A. K. Rajagopal

    2015-05-16

    We give an overview of joint unsharp measurements of non-commuting observables using positive operator valued measures (POVMs). We exemplify the role played by joint measurability of POVMs in entropic uncertainty relation for Alice's pair of non-commuting observables in the presence of Bob's entangled quantum memory. We show that Bob should record the outcomes of incompatible (non-jointly measurable) POVMs in his quantum memory so as to beat the entropic uncertainty bound. In other words, in addition to the presence of entangled Alice-Bob state, implementing incompatible POVMs at Bob's end is necessary to beat the uncertainty bound and hence, predict the outcomes of non-commuting observables with improved precision. We also explore the implications of joint measurability to {\\em validate} a moment matrix constructed from average pairwise correlations of three dichotomic non-commuting qubit observables. We prove that a classically acceptable moment matrix -- which ascertains the existence of a legitimate joint probability distribution for the outcomes of all the three dichotomic observables -- could be realized if and only if compatible POVMs are employed.

  2. Technique and application for quantifying dynamic shoulder joint kinematics and glenohumeral joint contact patterns

    E-print Network

    Massimini, Daniel Frank

    2014-01-01

    The shoulder (glenohumeral) joint has the greatest range of motion of all human joints; as a result, it is particularly vulnerable to dislocation and injury. The ability to accurately measure dynamic in-vivo joint kinematics ...

  3. Joint attention and language evolution

    NASA Astrophysics Data System (ADS)

    Kwisthout, Johan; Vogt, Paul; Haselager, Pim; Dijkstra, Ton

    2008-06-01

    This study investigates how more advanced joint attentional mechanisms, rather than only shared attention between two agents and an object, can be implemented and how they influence the results of language games played by these agents. We present computer simulations with language games showing that adding constructs that mimic the three stages of joint attention identified in children's early development (checking attention, following attention, and directing attention) substantially increase the performance of agents in these language games. In particular, the rates of improved performance for the individual attentional mechanisms have the same ordering as that of the emergence of these mechanisms in infants' development. These results suggest that language evolution and joint attentional mechanisms have developed in a co-evolutionary way, and that the evolutionary emergence of the individual attentional mechanisms is ordered just like their developmental emergence.

  4. Joint measurability through Naimark's theorem

    E-print Network

    Roberto Beneduci

    2015-10-09

    We use Naimark's dilation theorem in order to characterize the joint measurability of two POVMs. Then, we analyze the joint measurability of two commutative POVMs $F_1$ and $F_2$ which are the smearing of two self-adjoint operators $A_1$ and $A_2$ respectively. We prove that the compatibility of $F_1$ and $F_2$ is connected to the existence of two compatible self-adjoint dilations $A_1^+$ and $A_2^+$ of $A_1$ and $A_2$ respectively. As a corollary we prove that each couple of self-adjoint operators can be dilated to a couple of compatible self-adjoint operators. Next, we analyze the joint measurability of the unsharp position and momentum observables and show that it provides a master example of the scheme we propose. Finally, we give a sufficient condition for the compatibility of two effects.

  5. Coarsening of the Sn-Pb Solder Microstructure in Constitutive Model-Based Predictions of Solder Joint Thermal Mechanical Fatigue

    SciTech Connect

    Vianco, P.T.; Burchett, S.N.; Neilsen, M.K.; Rejent, J.A.; Frear, D.R.

    1999-04-12

    Thermal mechanical fatigue (TMF) is an important damage mechanism for solder joints exposed to cyclic temperature environments. Predicting the service reliability of solder joints exposed to such conditions requires two knowledge bases: first, the extent of fatigue damage incurred by the solder microstructure leading up to fatigue crack initiation, must be quantified in both time and space domains. Secondly, fatigue crack initiation and growth must be predicted since this metric determines, explicitly, the loss of solder joint functionality as it pertains to its mechanical fastening as well as electrical continuity roles. This paper will describe recent progress in a research effort to establish a microstructurally-based, constitutive model that predicts TMF deformation to 63Sn-37Pb solder in electronic solder joints up to the crack initiation step. The model is implemented using a finite element setting; therefore, the effects of both global and local thermal expansion mismatch conditions in the joint that would arise from temperature cycling.

  6. Time-frequency analysis of pediatric murmurs

    NASA Astrophysics Data System (ADS)

    Lombardo, Joseph S.; Blodgett, Lisa A.; Rosen, Ron S.; Najmi, Amir-Homayoon; Thompson, W. Reid

    1998-05-01

    Technology has provided many new tools to assist in the diagnosis of pathologic conditions of the heart. Echocardiography, Ultrafast CT, and MRI are just a few. While these tools are a valuable resource, they are typically too expensive, large and complex in operation for use in rural, homecare, and physician's office settings. Recent advances in computer performance, miniaturization, and acoustic signal processing, have yielded new technologies that when applied to heart sounds can provide low cost screening for pathologic conditions. The short duration and transient nature of these signals requires processing techniques that provide high resolution in both time and frequency. Short-time Fourier transforms, Wigner distributions, and wavelet transforms have been applied to signals form hearts with various pathologic conditions. While no single technique provides the ideal solution, the combination of tools provides a good representation of the acoustic features of the pathologies selected.

  7. Solder Joint Health Monitoring Testbed

    NASA Technical Reports Server (NTRS)

    Delaney, Michael M.; Flynn, James G.; Browder, Mark E.

    2009-01-01

    A method of monitoring the health of selected solder joints, called SJ-BIST, has been developed by Ridgetop Group Inc. under a Small Business Innovative Research (SBIR) contract. The primary goal of this research program is to test and validate this method in a flight environment using realistically seeded faults in selected solder joints. An additional objective is to gather environmental data for future development of physics-based and data-driven prognostics algorithms. A test board is being designed using a Xilinx FPGA. These boards will be tested both in flight and on the ground using a shaker table and an altitude chamber.

  8. [Divorce and joint physical custody].

    PubMed

    Golse, B

    2014-04-01

    This work first recalls the definition of joint physical custody, as well as the current legal procedure for obtaining it, its practical implementation, the financial implications for parents, and finally some statistics. Some psychological and psychopathological reflections on the impact of divorce on children are then presented before considering the question of joint physically custody with regard to attachment theory and depending on the age of the child (a great caution seems to be required before three years). The article concludes with a brief discussion of parental alienation syndrome. PMID:24630624

  9. Flexible joints for thrust vector control

    NASA Technical Reports Server (NTRS)

    Woodberry, R. F. H.

    1975-01-01

    Flexible joints have been used to achieve thrust vector control over a wide range of sizes of nozzles and have been demonstrated successfully in bench tests and static firings, and are operational on two motors. From these many joints the problems of flexible joints have been defined as establishment of the movable nozzle envelope, definition of the actuation power requirements, definition of the mechanical properties of joint materials, adhesive bonding, test methods, and quality control. These data and problem solutions are contained in a large number of reports. Data relating to joint configuration, design requirements, materials selection, joint design, structural analysis, manufacture, and testing are summarized.

  10. On Probability Domains III

    NASA Astrophysics Data System (ADS)

    Fri?, Roman; Pap?o, Martin

    2015-12-01

    Domains of generalized probability have been introduced in order to provide a general construction of random events, observables and states. It is based on the notion of a cogenerator and the properties of product. We continue our previous study and show how some other quantum structures fit our categorical approach. We discuss how various epireflections implicitly used in the classical probability theory are related to the transition to fuzzy probability theory and describe the latter probability theory as a genuine categorical extension of the former. We show that the IF-probability can be studied via the fuzzy probability theory. We outline a "tensor modification" of the fuzzy probability theory.

  11. Saliency detection in the compressed domain for adaptive image retargeting.

    PubMed

    Fang, Yuming; Chen, Zhenzhong; Lin, Weisi; Lin, Chia-Wen

    2012-09-01

    Saliency detection plays important roles in many image processing applications, such as regions of interest extraction and image resizing. Existing saliency detection models are built in the uncompressed domain. Since most images over Internet are typically stored in the compressed domain such as joint photographic experts group (JPEG), we propose a novel saliency detection model in the compressed domain in this paper. The intensity, color, and texture features of the image are extracted from discrete cosine transform (DCT) coefficients in the JPEG bit-stream. Saliency value of each DCT block is obtained based on the Hausdorff distance calculation and feature map fusion. Based on the proposed saliency detection model, we further design an adaptive image retargeting algorithm in the compressed domain. The proposed image retargeting algorithm utilizes multioperator operation comprised of the block-based seam carving and the image scaling to resize images. A new definition of texture homogeneity is given to determine the amount of removal block-based seams. Thanks to the directly derived accurate saliency information from the compressed domain, the proposed image retargeting algorithm effectively preserves the visually important regions for images, efficiently removes the less crucial regions, and therefore significantly outperforms the relevant state-of-the-art algorithms, as demonstrated with the in-depth analysis in the extensive experiments. PMID:22614642

  12. Joint Planck and WMAP CMB map reconstruction

    NASA Astrophysics Data System (ADS)

    Bobin, J.; Sureau, F.; Starck, J.-L.; Rassat, A.; Paykari, P.

    2014-03-01

    We present a novel estimate of the cosmological microwave background (CMB) map by combining the two latest full-sky microwave surveys: WMAP nine-year and Planck PR1. The joint processing benefits from a recently introduced component separation method coined"local-generalized morphological component analysis" (LGMCA) and based on the sparse distribution of the foregrounds in the wavelet domain. The proposed estimation procedure takes advantage of the IRIS 100 ?m as an extra observation on the galactic center for enhanced dust removal. We show that this new CMB map presents several interesting aspects: i) it is a full sky map without using any inpainting or interpolating method; ii) foreground contamination is very low; iii) the Galactic center is very clean with especially low dust contamination as measured by the cross-correlation between the estimated CMB map and the IRIS 100 ?m map; and iv) it is free of thermal SZ contamination. Appendix is available in electronic form at http://www.aanda.org

  13. Stress-relieved solder joints

    NASA Technical Reports Server (NTRS)

    Zemenick, C. J.

    1980-01-01

    Mechanical stress on solder joints is reduced by procedure for soldering electronic components to circuit boards. Procedure was developed for radio-frequency (RF) strip-line circuits, for which dimensions must be carefully controlled to minimize parasitic capacitance and inductance. Procedure consists of loosening component from its mounting after each lead is soldered relieving induced stresses before next soldering step.

  14. EUROPEAN SWALLOW RESEARCH: JOINT VENTURE

    E-print Network

    de Villiers, Marienne

    EUROPEAN SWALLOW RESEARCH: JOINT VENTURE William Scott P O Box 2680, Potchefstrcom 2520 After of theirfield trip collecting data andblood samples ofEuropean Swallows and other swallow and martin species my help in locating swallow roosts and help with their capture. Henk Bouwman, who had previously met

  15. Space station rotary joint mechanisms

    NASA Technical Reports Server (NTRS)

    Driskill, Glen W.

    1986-01-01

    The mechanism which will be used on the space station to position the solar arrays and radiator panels for Sun pointing and Sun avoidance is described. The unique design features will be demonstrated on advanced development models of two of the joints being fabricated under contract to NASA-MSFC.

  16. Plating To Reinforce Welded Joints

    NASA Technical Reports Server (NTRS)

    Otousa, J. E.

    1982-01-01

    Electrodeposition used to strengthen welded joints gouged, nicked, or suffered other mechanical damage. Plating cell, typically of acrylic plastic such as poly (Methylmetacrylate), is assembled around part to be plated. Areas not to be plated are masked with plater's tape. Weld area is plated in standard nickel-plating process.

  17. The Rationale for Joint Mobilization.

    ERIC Educational Resources Information Center

    Burkhardt, Sandy

    This paper presents an overview of the functions of connective tissue and the mechanisms of joint injury and contracture formation in relation to therapeutic exercise. The components of connective tissue operation are explained, including fibroblasts, macrophages, plasma cells, and collagen. An examination of the histology of connective tissue as…

  18. Joint Report NEC Europe Ltd.

    E-print Network

    Joint Report NEC Europe Ltd. Network Laboratories Kurfürsten-Anlage 36 D-69115 Heidelberg Germany Phone: +49 6221 90510 Fax: +49 6221 90511-55 http://www.netlab.nec.de Humboldt University Berlin Systems 2093-3112 http://sar.informatik.hu-berlin.de This report contains NEC confidential information

  19. Offered jointly with International Business

    E-print Network

    The world economy is a global one and international trade has an increasingly important role to playOffered jointly with Master in International Business #12;.02 Welcome to Barcelona Welcome to UPF been classified as a Campus of International Excellence in a move promoted by the Ministry of Education

  20. Joint measurements and Svetlichny's inequality

    E-print Network

    Yang Xiang; Wei Ren

    2010-12-27

    We prove that the Svetlichny's inequality can be derived from the existence of joint measurements and the principle of no-signaling. Then we show that, on the basis of quantum measurement assumption, it would imply the breach of causality if the magnitude of violation of Svetlichny's inequality exceeds quantum bound.

  1. Joint BioEnergy Institute

    SciTech Connect

    Keasling, Jay; Simmons, Blake; Tartaglino, Virginia; Baidoo, Edward; Kothari, Ankita

    2015-06-15

    The Joint BioEnergy Institute (JBEI) is a U.S. Department of Energy (DOE) Bioenergy Research Center dedicated to developing advanced biofuels—liquid fuels derived from the solar energy stored in plant biomass that can replace gasoline, diesel and jet fuels.

  2. Cryopumping Field Joint Can Testing

    NASA Technical Reports Server (NTRS)

    Johnson, Wesley L.; Fesmire, James E.; Meneghelli, Barry E.

    2011-01-01

    For long installations, vacuum jacketed piping often comes in 40 foot sections that are butt welded together in the field. A short can is then welded over the bare pipe connection to allow for insulation to be protected from the environment. Traditionally, the field joint is insulated with multilayer insulation and a vacuum is pulled on the can to minimize heat leak through the bare section and prevent frost from forming on the pipe section. The vacuum jacketed lines for the Ares I mobile launch platform were to be a combined 2000 feet long, with 60+ pipe sections and field joint cans. Historically, Kennedy Space Center has drilled a hole in the long sections to create a common vacuum with the field joint can to minimize maintenance on the vacuum jacketed piping. However, this effort looked at ways to use a passive system that didn't require a vacuum, but may cryopump to create its own vacuum. Various forms of aerogel, multilayer insulations, and combinations thereof were tested to determine the best method of insulating the field joint while minimizing maintenance and thermal losses.

  3. Knee joint replacement prosthesis (image)

    MedlinePLUS

    A prosthesis is a device designed to replace a missing part of the body, or to make a part of the body work better. The metal prosthetic device in knee joint replacement surgery replaces cartilage and bone which is damaged from disease or aging.

  4. Joint Disorders - Multiple Languages: MedlinePlus

    MedlinePLUS

    ... ?????????? ?????? ??????? - ??????? Bilingual PDF Health Information Translations Bosnian (Bosanski) Home Care After Total Joint Replacement ... zamjene zgloba - Bosanski (Bosnian) Bilingual PDF Health Information Translations Chinese - Simplified (????) Home Care After Total Joint ...

  5. Joint action without and beyond planning 

    E-print Network

    Blomberg, Karl Johan Olof; Blomberg, Olle

    2013-07-02

    Leading philosophical accounts of joint activity, such as Michael Bratman’s account of ‘shared intentional activity’, take joint activity to be the outcome of two or more agents having a ‘shared intention’, where this ...

  6. 49 CFR 192.233 - Miter joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.233 Miter joints. (a) A miter joint on steel pipe to be operated at a pressure...

  7. Aging changes in the bones - muscles - joints

    MedlinePLUS

    ... skeleton provides support and structure to the body. Joints are the areas where bones come together. They ... skeleton to be flexible for movement. In a joint, bones do not directly contact each other. Instead, ...

  8. Skilled nursing facilities after joint replacement

    MedlinePLUS

    ... from the hospital after surgery to replace a joint. Even if you and your doctor planned for ... doctors and nurses in the weeks before your joint replacement. They can advise you about whether going ...

  9. Older Person's Guide to Joint Replacement

    MedlinePLUS

    ... Osteoporosis Related Documents PDF Older Person’s Guide to Joint Replacement Download Join our e-newsletter! Resources Older Person’s Guide to Joint Replacement Tools and Tips Printer-friendly PDF Click ...

  10. JOINT WELCOME LECTURE PROF. DR. SEBASTIAN BSER

    E-print Network

    Kaus, Boris

    JOINT WELCOME LECTURE PROF. DR. SEBASTIAN BÖSER PROF. DR. JOACHIM KOPP PROF. DR. MICHAEL WURM:15: Laudatio, followed by joint lecture The Invisibles: Neutrinos on Earth and in the Sky #12;Dear colleagues

  11. Joint CQSE and CASTS Seminar Weekly Seminar

    E-print Network

    Wu, Yih-Min

    Joint CQSE and CASTS Seminar Weekly Seminar Dec. 23, 2011 (Friday) TIME Dec. 23, 14:30 ~ 15 evaluated around the future lightcone of the joint measurement by Alice. The distortion of the quantum state

  12. Bayesian Joint Modelling for Object Localisation in Weakly Labelled Images.

    PubMed

    Shi, Zhiyuan; Hospedales, Timothy M; Xiang, Tao

    2015-10-01

    We address the problem of localisation of objects as bounding boxes in images and videos with weak labels. This weakly supervised object localisation problem has been tackled in the past using discriminative models where each object class is localised independently from other classes. In this paper, a novel framework based on Bayesian joint topic modelling is proposed, which differs significantly from the existing ones in that: (1) All foreground object classes are modelled jointly in a single generative model that encodes multiple object co-existence so that "explaining away" inference can resolve ambiguity and lead to better learning and localisation. (2) Image backgrounds are shared across classes to better learn varying surroundings and "push out" objects of interest. (3) Our model can be learned with a mixture of weakly labelled and unlabelled data, allowing the large volume of unlabelled images on the Internet to be exploited for learning. Moreover, the Bayesian formulation enables the exploitation of various types of prior knowledge to compensate for the limited supervision offered by weakly labelled data, as well as Bayesian domain adaptation for transfer learning. Extensive experiments on the PASCAL VOC, ImageNet and YouTube-Object videos datasets demonstrate the effectiveness of our Bayesian joint model for weakly supervised object localisation. PMID:26340253

  13. Joint interaction with embedded concretions: joint loading congurations inferred from propagation paths

    E-print Network

    Engelder, Terry

    Joint interaction with embedded concretions: joint loading con®gurations inferred from propagation The interaction between propagating joints and embedded concretions in a Devonian black shale near Seneca Lake, NY, permits identi®cation of the loading con®gurations responsible for two joint sets of dierent ages striking

  14. Evaluation of the Effect of Mega MSM on Improving Joint Function in Populations Experiencing Joint Degeneration

    PubMed Central

    Xu, Gang; Zhou, Tian; Gu, Yaqin; Wang, Qinping; Shariff, Mina; Gu, Pingping; Nguyen, Tuong; Shi, Rong; Rao, Jianyu

    2015-01-01

    Joint degeneration has become a commonplace problem in aging populations. The main clinical manifestations include joint pain, joint stiffness and joint swelling with functional disorder. Mega MSM is a nutritional supplement that may provide potential relief for joint problems associated with joint degeneration. The current experiment performed was a 12-week, randomized, double-blind, controlled study conducted on populations in China experiencing joint degeneration. The objective of the study was to determine whether the daily use of Mega MSM capsules could improve joint function, relieve symptoms of joint degeneration and improve the quality of life in aging populations. A total of 100 male and female participants over 50 years old who had at least one of the related symptoms of joint degeneration (joint pain, joint stiffness, joint swelling, difficulty walking, difficulty getting up from bed and difficulty going down stairs) were recruited and their symptoms of joint degeneration before and after the intervention were recorded. In this study, Mega MSM shows positive effects in improving joint function, relieving symptoms associated with joint degeneration and improving the quality of life in aging populations. PMID:26199577

  15. 26 CFR 1.6015-1 - Relief from joint and several liability on a joint return.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Relief from joint and several liability on a joint return. 1.6015-1 Section 1.6015-1...Returns Or Statements § 1.6015-1 Relief from joint and several liability on a joint return....

  16. 26 CFR 1.6015-1 - Relief from joint and several liability on a joint return.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Relief from joint and several liability on a joint return. 1.6015-1 Section 1.6015-1...Returns Or Statements § 1.6015-1 Relief from joint and several liability on a joint return....

  17. 26 CFR 1.6015-1 - Relief from joint and several liability on a joint return.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Relief from joint and several liability on a joint return. 1.6015-1 Section 1.6015-1...Returns Or Statements § 1.6015-1 Relief from joint and several liability on a joint return....

  18. 26 CFR 1.6015-1 - Relief from joint and several liability on a joint return.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Relief from joint and several liability on a joint return. 1.6015-1 Section 1.6015-1...Returns Or Statements § 1.6015-1 Relief from joint and several liability on a joint return....

  19. 26 CFR 1.6015-1 - Relief from joint and several liability on a joint return.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Relief from joint and several liability on a joint return. 1.6015-1 Section 1.6015-1...Returns Or Statements § 1.6015-1 Relief from joint and several liability on a joint return....

  20. Navigating Joint Projects in Telephone Conversations

    ERIC Educational Resources Information Center

    Bangerter, Adrian; Clark, Herbert H.; Katz, Anna R.

    2004-01-01

    Conversation coordinates joint activities and the joint projects that compose them. Participants coordinate (1) vertical transitions on entering and exiting joint projects; and (2) horizontal transitions in continuing within them. Transitions are coordinated using project markers such as uh-huh, yeah, right, and okay. In the authors' proposal,…

  1. Behavior of jointed ductile iron pipelines

    SciTech Connect

    Singhal, A.C.

    1984-03-01

    Experimental data on the axial, bending, and torsional behavior of a pipeline joint demonstrated, in particular, the relationship between the load and the deflection behavior of a rubber gasketed joint in a ductile cast iron pipe. These results, along with analytical expressions, are especially useful in predicting the earthquake behavior of buried pipelines with flexible joints.

  2. 30 CFR 36.24 - Engine joints.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Engine joints. 36.24 Section 36.24 Mineral... MINING PRODUCTS APPROVAL REQUIREMENTS FOR PERMISSIBLE MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Construction and Design Requirements § 36.24 Engine joints. (a) Cylinder head. The joint between the...

  3. 30 CFR 36.24 - Engine joints.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Engine joints. 36.24 Section 36.24 Mineral... MINING PRODUCTS APPROVAL REQUIREMENTS FOR PERMISSIBLE MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Construction and Design Requirements § 36.24 Engine joints. (a) Cylinder head. The joint between the...

  4. 30 CFR 36.24 - Engine joints.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Engine joints. 36.24 Section 36.24 Mineral... MINING PRODUCTS APPROVAL REQUIREMENTS FOR PERMISSIBLE MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Construction and Design Requirements § 36.24 Engine joints. (a) Cylinder head. The joint between the...

  5. 30 CFR 36.24 - Engine joints.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Engine joints. 36.24 Section 36.24 Mineral... MINING PRODUCTS APPROVAL REQUIREMENTS FOR PERMISSIBLE MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Construction and Design Requirements § 36.24 Engine joints. (a) Cylinder head. The joint between the...

  6. 78 FR 14620 - Joint Development: Proposed Circular

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-06

    ...FTA-2013-0013] Joint Development: Proposed Circular...the docket and on its web site proposed guidance...circular, on joint development. This circular provides...when pursuing a joint development project. This following...be found on FTA's Web site at...

  7. of Concrete Pavements Joint PerformanCe

    E-print Network

    of Concrete Pavements Joint PerformanCe interim Guide for optimum JUNE 2012 #12;#12;Interim Guide for Optimum Joint Performance of Concrete Pavements i Technical Report Documentation Page 1. Report No. 2 for Optimum Joint Performance of Concrete Pavements September 2011 6. Performing Organization Code 7. Author

  8. 77 FR 39560 - International Joint Commission

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-03

    ... From the Federal Register Online via the Government Printing Office DEPARTMENT OF STATE International Joint Commission International Joint Commission Invites Public Comment on Upper Great Lakes Report The International Joint Commission (IJC) announced today that it is inviting public comment on the final report of its International Upper...

  9. 49 CFR 178.345-4 - Joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Joints. 178.345-4 Section 178.345-4 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers for Motor Vehicle Transportation § 178.345-4 Joints. (a) All joints between the cargo tank...

  10. 14 CFR 296.4 - Joint loading.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Joint loading. 296.4 Section 296.4... REGULATIONS INDIRECT AIR TRANSPORTATION OF PROPERTY General § 296.4 Joint loading. Nothing in this part shall preclude joint loading, meaning the pooling of shipments and their delivery to a direct air carrier...

  11. 11 CFR 9034.8 - Joint fundraising.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 11 CFR 110.11, a joint fundraising notice shall be included with every solicitation for contributions... CFR 100.5; (B) The allocation formula to be used for distributing joint fundraising proceeds; (C) A... as defined in 11 CFR 110.3 prior to the joint fundraising activity and are not committees of the...

  12. 14 CFR 297.4 - Joint loading.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Joint loading. 297.4 Section 297.4... REGULATIONS FOREIGN AIR FREIGHT FORWARDERS AND FOREIGN COOPERATIVE SHIPPERS ASSOCIATIONS General § 297.4 Joint loading. Nothing in this part shall preclude joint loading, meaning the pooling of shipments and...

  13. 49 CFR 178.338-4 - Joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Joints. 178.338-4 Section 178.338-4 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers for Motor Vehicle Transportation § 178.338-4 Joints. (a) All joints in the tank, and in the...

  14. 46 CFR 385.38 - Joint funding.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Joint funding. 385.38 Section 385.38 Shipping MARITIME... AGREEMENTS REGULATIONS General Policies § 385.38 Joint funding. (a) Pursuant to section 10(c) of the Act, MarAd is authorized to participate in joint funded projects with other Federal agencies in any...

  15. 49 CFR 583.15 - Joint ownership.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Joint ownership. 583.15 Section 583.15... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AUTOMOBILE PARTS CONTENT LABELING § 583.15 Joint... joint owners of a carline may designate, by written agreement, the manufacturer of record of...

  16. 49 CFR 192.233 - Miter joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Miter joints. 192.233 Section 192.233... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.233 Miter joints. (a) A miter joint on steel pipe to be operated at a pressure that produces a hoop stress of...

  17. 7 CFR 1400.203 - Joint operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Joint operations. 1400.203 Section 1400.203... AND SUBSEQUENT CROP, PROGRAM, OR FISCAL YEARS Payment Eligibility § 1400.203 Joint operations. (a) A member of a joint operation will be considered to be actively engaged in farming with respect to...

  18. 42 CFR 423.1040 - Joint hearings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 3 2013-10-01 2013-10-01 false Joint hearings. 423.1040 Section 423.1040 Public... Penalties § 423.1040 Joint hearings. When two or more affected parties have requested hearings and the same... and place for the prehearing conference or hearing and conduct all proceedings jointly. If...

  19. 49 CFR 225.23 - Joint operations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Joint operations. 225.23 Section 225.23....23 Joint operations. (a) Any reportable death, injury, or illness of an employee arising from an accident/incident involving joint operations must be reported on Form FRA F 6180.55a by the...

  20. 14 CFR 297.4 - Joint loading.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Joint loading. 297.4 Section 297.4... REGULATIONS FOREIGN AIR FREIGHT FORWARDERS AND FOREIGN COOPERATIVE SHIPPERS ASSOCIATIONS General § 297.4 Joint loading. Nothing in this part shall preclude joint loading, meaning the pooling of shipments and...

  1. Joint action: bodies and minds moving together

    E-print Network

    Richardson, Daniel C.

    Joint action: bodies and minds moving together Natalie Sebanz1 , Harold Bekkering2 and Gu¨ nther as individuals and as a species. Progress in understanding the cognitive and neural processes involved in joint perception and action in social context. In this article we outline how studies on joint attention, action

  2. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Joint employment. 791.2 Section 791.2 Labor Regulations... INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single individual may stand in the relation of an employee...

  3. 49 CFR 225.23 - Joint operations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Joint operations. 225.23 Section 225.23....23 Joint operations. (a) Any reportable death, injury, or illness of an employee arising from an accident/incident involving joint operations must be reported on Form FRA F 6180.55a by the...

  4. 14 CFR 296.4 - Joint loading.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Joint loading. 296.4 Section 296.4... REGULATIONS INDIRECT AIR TRANSPORTATION OF PROPERTY General § 296.4 Joint loading. Nothing in this part shall preclude joint loading, meaning the pooling of shipments and their delivery to a direct air carrier...

  5. 7 CFR 1400.203 - Joint operations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Joint operations. 1400.203 Section 1400.203... AND SUBSEQUENT CROP, PROGRAM, OR FISCAL YEARS Payment Eligibility § 1400.203 Joint operations. (a) A member of a joint operation will be considered to be actively engaged in farming with respect to...

  6. JOINT PROGRAM IN TRANSPORTATION UNIVERSITY OF TORONTO

    E-print Network

    Toronto, University of

    JOINT PROGRAM IN TRANSPORTATION UNIVERSITY OF TORONTO 2001 TRANSPORTATION TOMORROW SURVEY not to participate) #12;JOINT PROGRAM IN TRANSPORTATION UNIVERSITY OF TORONTO 2001 TRANSPORTATION TOMORROW SURVEY Survey Area 2001 only 1996 only 1996 and 2001 1986, 1991, 1996 and 2001 #12;JOINT PROGRAM

  7. 49 CFR 583.15 - Joint ownership.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Joint ownership. 583.15 Section 583.15... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AUTOMOBILE PARTS CONTENT LABELING § 583.15 Joint... joint owners of a carline may designate, by written agreement, the manufacturer of record of...

  8. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Joint employment. 791.2 Section 791.2 Labor Regulations... INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single individual may stand in the relation of an employee...

  9. 42 CFR 498.54 - Joint hearings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 5 2011-10-01 2011-10-01 false Joint hearings. 498.54 Section 498.54 Public Health... PROGRAM Hearings § 498.54 Joint hearings. When two or more affected parties have requested hearings and... joint hearings are held, a single record of the preceedings is made and a separate decision issued...

  10. 14 CFR 25.693 - Joints.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Joints. 25.693 Section 25.693 Aeronautics... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Control Systems § 25.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion, except those in ball and...

  11. 7 CFR 1956.110 - Joint debtors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 14 2010-01-01 2009-01-01 true Joint debtors. 1956.110 Section 1956.110 Agriculture... REGULATIONS (CONTINUED) DEBT SETTLEMENT Debt Settlement-Community and Business Programs § 1956.110 Joint debtors. Settlements may not be approved for one joint debtor unless approved for all debtors....

  12. 29 CFR 570.115 - Joint applicability.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Joint applicability. 570.115 Section 570.115 Labor... Provisions of the Fair Labor Standards Act of 1938, as Amended Joint and Separate Applicability of Sections 12(a) and 12(c) § 570.115 Joint applicability. The child labor coverage provisions contained...

  13. 18 CFR 154.307 - Joint facilities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Joint facilities. 154... Changes § 154.307 Joint facilities. The Statements required by § 154.312 must show all costs (investment... in the subject rate change and are associated with joint facilities. The methods used in making...

  14. 49 CFR 1112.5 - Joint pleadings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 8 2011-10-01 2011-10-01 false Joint pleadings. 1112.5 Section 1112.5... OF TRANSPORTATION RULES OF PRACTICE MODIFIED PROCEDURES § 1112.5 Joint pleadings. Parties with common interests are encouraged to prepare joint pleadings whenever possible....

  15. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Joint employment. 791.2 Section 791.2 Labor Regulations... INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single individual may stand in the relation of an employee...

  16. 11 CFR 9034.8 - Joint fundraising.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 CFR 110.11, a joint fundraising notice shall be included with every solicitation for contributions... CFR 100.5; (B) The allocation formula to be used for distributing joint fundraising proceeds; (C) A... as defined in 11 CFR 110.3 prior to the joint fundraising activity and are not committees of the...

  17. 49 CFR 583.15 - Joint ownership.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Joint ownership. 583.15 Section 583.15... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AUTOMOBILE PARTS CONTENT LABELING § 583.15 Joint... joint owners of a carline may designate, by written agreement, the manufacturer of record of...

  18. 38 CFR 4.66 - Sacroiliac joint.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false Sacroiliac joint. 4.66... DISABILITIES Disability Ratings The Musculoskeletal System § 4.66 Sacroiliac joint. The common cause of... joints should be considered as one anatomical segment for rating purposes. X-ray changes from...

  19. 49 CFR 178.345-4 - Joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Joints. 178.345-4 Section 178.345-4 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers for Motor Vehicle Transportation § 178.345-4 Joints. (a) All joints between the cargo tank...

  20. 14 CFR 399.37 - Joint fares.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Joint fares. 399.37 Section 399.37... STATEMENTS STATEMENTS OF GENERAL POLICY Policies Relating to Rates and Tariffs § 399.37 Joint fares. There should be joint fares in all markets over all routings within the contiguous 48 states and the...