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Sample records for bidimensional empirical mode

  1. Noise reduction in digital speckle pattern interferometry using bidimensional empirical mode decomposition

    International Nuclear Information System (INIS)

    Bernini, Maria Belen; Federico, Alejandro; Kaufmann, Guillermo H.

    2008-01-01

    We propose a bidimensional empirical mode decomposition (BEMD) method to reduce speckle noise in digital speckle pattern interferometry (DSPI) fringes. The BEMD method is based on a sifting process that decomposes the DSPI fringes in a finite set of subimages represented by high and low frequency oscillations, which are named modes. The sifting process assigns the high frequency information to the first modes, so that it is possible to discriminate speckle noise from fringe information, which is contained in the remaining modes. The proposed method is a fully data-driven technique, therefore neither fixed basis functions nor operator intervention are required. The performance of the BEMD method to denoise DSPI fringes is analyzed using computer-simulated data, and the results are also compared with those obtained by means of a previously developed one-dimensional empirical mode decomposition approach. An application of the proposed BEMD method to denoise experimental fringes is also presented

  2. Automatic fringe enhancement with novel bidimensional sinusoids-assisted empirical mode decomposition.

    Science.gov (United States)

    Wang, Chenxing; Kemao, Qian; Da, Feipeng

    2017-10-02

    Fringe-based optical measurement techniques require reliable fringe analysis methods, where empirical mode decomposition (EMD) is an outstanding one due to its ability of analyzing complex signals and the merit of being data-driven. However, two challenging issues hinder the application of EMD in practical measurement. One is the tricky mode mixing problem (MMP), making the decomposed intrinsic mode functions (IMFs) have equivocal physical meaning; the other is the automatic and accurate extraction of the sinusoidal fringe from the IMFs when unpredictable and unavoidable background and noise exist in real measurements. Accordingly, in this paper, a novel bidimensional sinusoids-assisted EMD (BSEMD) is proposed to decompose a fringe pattern into mono-component bidimensional IMFs (BIMFs), with the MMP solved; properties of the resulted BIMFs are then analyzed to recognize and enhance the useful fringe component. The decomposition and the fringe recognition are integrated and the latter provides a feedback to the former, helping to automatically stop the decomposition to make the algorithm simpler and more reliable. A series of experiments show that the proposed method is accurate, efficient and robust to various fringe patterns even with poor quality, rendering it a potential tool for practical use.

  3. Multisource Remote Sensing Imagery Fusion Scheme Based on Bidimensional Empirical Mode Decomposition (BEMD and Its Application to the Extraction of Bamboo Forest

    Directory of Open Access Journals (Sweden)

    Guang Liu

    2016-12-01

    Full Text Available Most bamboo forests grow in humid climates in low-latitude tropical or subtropical monsoon areas, and they are generally located in hilly areas. Bamboo trunks are very straight and smooth, which means that bamboo forests have low structural diversity. These features are beneficial to synthetic aperture radar (SAR microwave penetration and they provide special information in SAR imagery. However, some factors (e.g., foreshortening can compromise the interpretation of SAR imagery. The fusion of SAR and optical imagery is considered an effective method with which to obtain information on ground objects. However, most relevant research has been based on two types of remote sensing image. This paper proposes a new fusion scheme, which combines three types of image simultaneously, based on two fusion methods: bidimensional empirical mode decomposition (BEMD and the Gram-Schmidt transform. The fusion of panchromatic and multispectral images based on the Gram-Schmidt transform can enhance spatial resolution while retaining multispectral information. BEMD is an adaptive decomposition method that has been applied widely in the analysis of nonlinear signals and to the nonstable signal of SAR. The fusion of SAR imagery with fused panchromatic and multispectral imagery using BEMD is based on the frequency information of the images. It was established that the proposed fusion scheme is an effective remote sensing image interpretation method, and that the value of entropy and the spatial frequency of the fused images were improved in comparison with other techniques such as the discrete wavelet, à-trous, and non-subsampled contourlet transform methods. Compared with the original image, information entropy of the fusion image based on BEMD improves about 0.13–0.38. Compared with the other three methods it improves about 0.06–0.12. The average gradient of BEMD is 4%–6% greater than for other methods. BEMD maintains spatial frequency 3.2–4.0 higher than

  4. Comparison of two interpolation methods for empirical mode decomposition based evaluation of radiographic femur bone images.

    Science.gov (United States)

    Udhayakumar, Ganesan; Sujatha, Chinnaswamy Manoharan; Ramakrishnan, Swaminathan

    2013-01-01

    Analysis of bone strength in radiographic images is an important component of estimation of bone quality in diseases such as osteoporosis. Conventional radiographic femur bone images are used to analyze its architecture using bi-dimensional empirical mode decomposition method. Surface interpolation of local maxima and minima points of an image is a crucial part of bi-dimensional empirical mode decomposition method and the choice of appropriate interpolation depends on specific structure of the problem. In this work, two interpolation methods of bi-dimensional empirical mode decomposition are analyzed to characterize the trabecular femur bone architecture of radiographic images. The trabecular bone regions of normal and osteoporotic femur bone images (N = 40) recorded under standard condition are used for this study. The compressive and tensile strength regions of the images are delineated using pre-processing procedures. The delineated images are decomposed into their corresponding intrinsic mode functions using interpolation methods such as Radial basis function multiquadratic and hierarchical b-spline techniques. Results show that bi-dimensional empirical mode decomposition analyses using both interpolations are able to represent architectural variations of femur bone radiographic images. As the strength of the bone depends on architectural variation in addition to bone mass, this study seems to be clinically useful.

  5. ECHOCARDIOGRAPHIC FINDINGS OF BIDIMENSIONAL MODE, M-MODE, AND DOPPLER OF CLINICALLY NORMAL BLACK-RUMPED AGOUTI (DASYPROCTA PRYMNOLOPHA, WAGLER 1831).

    Science.gov (United States)

    Diniz, Anaemilia das Neves; Pessoa, Gerson Tavares; da Silva Moura, Laecio; de Sousa, André Braga; Sousa, Francisco das Chagas Araújo; de Sá Rodrigues, Renan Paraguassu; da Silva Barbosa, Maria Angélica Parente; de Almeida, Hatawa Melo; Freire, Larisse Danielle Silva; Sanches, Marina Pinto; Júnior, Antônio Augusto Nascimento Machado; Guerra, Porfírio Candanedo; Neves, Willams Costa; de Sousa, João Macedo; Bolfer, Luiz; Giglio, Robson Fortes; Alves, Flávio Ribeiro

    2017-06-01

    The black-rumped agouti ( Dasyprocta prymnolopha , Wagler 1831) is currently under intense ecologic pressure, which has resulted in its disappearance from some regions of Brazil. Echocardiography is widely used in veterinary medicine but it is not yet part of the clinical routine for wild animals. The objective of the present study was to assess the applicability of the echocardiographic exam in nonanesthetized agouti and to establish normal reference values for echocardiographic measurements in bidimensional mode (2D), M-mode, and Doppler for this species, and a lead II electrocardiogram was simultaneously recorded. Twenty agouti were used in this study. All the echocardiographic measurements were positively correlated with weight (P 0.05). Blood flow velocities in the pulmonary and aortic artery ranged from 67.32-71.28 cm/sec and 79.22-101.84 cm/sec, respectively. The isovolumic relaxation time was assessed in all the animals and ranged from 38.5 to 56.6 ms. The maximum value for the nonfused E and A waves and the Et and At waves was 158 beats/min for both. The results obtained for the morphologic and heart hemodynamic measurements can guide future studies and help in the clinical management of these animals in captivity.

  6. Univariate and Bivariate Empirical Mode Decomposition for Postural Stability Analysis

    Directory of Open Access Journals (Sweden)

    Jacques Duchêne

    2008-05-01

    Full Text Available The aim of this paper was to compare empirical mode decomposition (EMD and two new extended methods of  EMD named complex empirical mode decomposition (complex-EMD and bivariate empirical mode decomposition (bivariate-EMD. All methods were used to analyze stabilogram center of pressure (COP time series. The two new methods are suitable to be applied to complex time series to extract complex intrinsic mode functions (IMFs before the Hilbert transform is subsequently applied on the IMFs. The trace of the analytic IMF in the complex plane has a circular form, with each IMF having its own rotation frequency. The area of the circle and the average rotation frequency of IMFs represent efficient indicators of the postural stability status of subjects. Experimental results show the effectiveness of these indicators to identify differences in standing posture between groups.

  7. Instantaneous Respiratory Estimation from Thoracic Impedance by Empirical Mode Decomposition

    OpenAIRE

    Wang, Fu-Tai; Chan, Hsiao-Lung; Wang, Chun-Li; Jian, Hung-Ming; Lin, Sheng-Hsiung

    2015-01-01

    Impedance plethysmography provides a way to measure respiratory activity by sensing the change of thoracic impedance caused by inspiration and expiration. This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring. The empirical mode decomposition (EMD) can decompose a signal into several intrinsic mode functions (IMFs) that disclos...

  8. Failure mode and effects analysis: an empirical comparison of failure mode scoring procedures.

    Science.gov (United States)

    Ashley, Laura; Armitage, Gerry

    2010-12-01

    To empirically compare 2 different commonly used failure mode and effects analysis (FMEA) scoring procedures with respect to their resultant failure mode scores and prioritization: a mathematical procedure, where scores are assigned independently by FMEA team members and averaged, and a consensus procedure, where scores are agreed on by the FMEA team via discussion. A multidisciplinary team undertook a Healthcare FMEA of chemotherapy administration. This included mapping the chemotherapy process, identifying and scoring failure modes (potential errors) for each process step, and generating remedial strategies to counteract them. Failure modes were scored using both an independent mathematical procedure and a team consensus procedure. Almost three-fifths of the 30 failure modes generated were scored differently by the 2 procedures, and for just more than one-third of cases, the score discrepancy was substantial. Using the Healthcare FMEA prioritization cutoff score, almost twice as many failure modes were prioritized by the consensus procedure than by the mathematical procedure. This is the first study to empirically demonstrate that different FMEA scoring procedures can score and prioritize failure modes differently. It found considerable variability in individual team members' opinions on scores, which highlights the subjective and qualitative nature of failure mode scoring. A consensus scoring procedure may be most appropriate for FMEA as it allows variability in individuals' scores and rationales to become apparent and to be discussed and resolved by the team. It may also yield team learning and communication benefits unlikely to result from a mathematical procedure.

  9. Time-frequency analysis : mathematical analysis of the empirical mode decomposition.

    Science.gov (United States)

    2009-01-01

    Invented over 10 years ago, empirical mode : decomposition (EMD) provides a nonlinear : time-frequency analysis with the ability to successfully : analyze nonstationary signals. Mathematical : Analysis of the Empirical Mode Decomposition : is a...

  10. Palm vein recognition based on directional empirical mode decomposition

    Science.gov (United States)

    Lee, Jen-Chun; Chang, Chien-Ping; Chen, Wei-Kuei

    2014-04-01

    Directional empirical mode decomposition (DEMD) has recently been proposed to make empirical mode decomposition suitable for the processing of texture analysis. Using DEMD, samples are decomposed into a series of images, referred to as two-dimensional intrinsic mode functions (2-D IMFs), from finer to large scale. A DEMD-based 2 linear discriminant analysis (LDA) for palm vein recognition is proposed. The proposed method progresses through three steps: (i) a set of 2-D IMF features of various scale and orientation are extracted using DEMD, (ii) the 2LDA method is then applied to reduce the dimensionality of the feature space in both the row and column directions, and (iii) the nearest neighbor classifier is used for classification. We also propose two strategies for using the set of 2-D IMF features: ensemble DEMD vein representation (EDVR) and multichannel DEMD vein representation (MDVR). In experiments using palm vein databases, the proposed MDVR-based 2LDA method achieved recognition accuracy of 99.73%, thereby demonstrating its feasibility for palm vein recognition.

  11. Improved Wind Speed Prediction Using Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    ZHANG, Y.

    2018-05-01

    Full Text Available Wind power industry plays an important role in promoting the development of low-carbon economic and energy transformation in the world. However, the randomness and volatility of wind speed series restrict the healthy development of the wind power industry. Accurate wind speed prediction is the key to realize the stability of wind power integration and to guarantee the safe operation of the power system. In this paper, combined with the Empirical Mode Decomposition (EMD, the Radial Basis Function Neural Network (RBF and the Least Square Support Vector Machine (SVM, an improved wind speed prediction model based on Empirical Mode Decomposition (EMD-RBF-LS-SVM is proposed. The prediction result indicates that compared with the traditional prediction model (RBF, LS-SVM, the EMD-RBF-LS-SVM model can weaken the random fluctuation to a certain extent and improve the short-term accuracy of wind speed prediction significantly. In a word, this research will significantly reduce the impact of wind power instability on the power grid, ensure the power grid supply and demand balance, reduce the operating costs in the grid-connected systems, and enhance the market competitiveness of the wind power.

  12. Color Multifocus Image Fusion Using Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    S. Savić

    2013-11-01

    Full Text Available In this paper, a recently proposed grayscale multifocus image fusion method based on the first level of Empirical Mode Decomposition (EMD has been extended to color images. In addition, this paper deals with low contrast multifocus image fusion. The major advantages of the proposed methods are simplicity, absence of artifacts and control of contrast, while this isn’t the case with other pyramidal multifocus fusion methods. The efficiency of the proposed method is tested subjectively and with a vector gradient based objective measure, that is proposed in this paper for multifocus color image fusion. Subjective analysis performed on a multifocus image dataset has shown its superiority to the existing EMD and DWT based methods. The objective measures of grayscale and color image fusion show significantly better scores for this method than for the classic complex EMD fusion method.

  13. Instantaneous Respiratory Estimation from Thoracic Impedance by Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Fu-Tai Wang

    2015-07-01

    Full Text Available Impedance plethysmography provides a way to measure respiratory activity by sensing the change of thoracic impedance caused by inspiration and expiration. This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring. The empirical mode decomposition (EMD can decompose a signal into several intrinsic mode functions (IMFs that disclose nonstationary components as well as stationary components and, similarly, capture respiratory episodes from thoracic impedance. However, upper-body movements usually produce motion artifacts that are not easily removed by digital filtering. Moreover, large motion artifacts disable the EMD to decompose respiratory components. In this paper, motion artifacts are detected and replaced by the data mirrored from the prior and the posterior before EMD processing. A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation. Based on the experiments performing a series of static and dynamic physical activates, our results showed the proposed method had higher cross correlations between respiratory frequencies estimated from thoracic impedance and those from oronasal airflow based on small window size compared to the Fourier transform-based method.

  14. Instantaneous Respiratory Estimation from Thoracic Impedance by Empirical Mode Decomposition.

    Science.gov (United States)

    Wang, Fu-Tai; Chan, Hsiao-Lung; Wang, Chun-Li; Jian, Hung-Ming; Lin, Sheng-Hsiung

    2015-07-07

    Impedance plethysmography provides a way to measure respiratory activity by sensing the change of thoracic impedance caused by inspiration and expiration. This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring. The empirical mode decomposition (EMD) can decompose a signal into several intrinsic mode functions (IMFs) that disclose nonstationary components as well as stationary components and, similarly, capture respiratory episodes from thoracic impedance. However, upper-body movements usually produce motion artifacts that are not easily removed by digital filtering. Moreover, large motion artifacts disable the EMD to decompose respiratory components. In this paper, motion artifacts are detected and replaced by the data mirrored from the prior and the posterior before EMD processing. A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation. Based on the experiments performing a series of static and dynamic physical activates, our results showed the proposed method had higher cross correlations between respiratory frequencies estimated from thoracic impedance and those from oronasal airflow based on small window size compared to the Fourier transform-based method.

  15. Health monitoring of pipeline girth weld using empirical mode decomposition

    Science.gov (United States)

    Rezaei, Davood; Taheri, Farid

    2010-05-01

    In the present paper the Hilbert-Huang transform (HHT), as a time-series analysis technique, has been combined with a local diagnostic approach in an effort to identify flaws in pipeline girth welds. This method is based on monitoring the free vibration signals of the pipe at its healthy and flawed states, and processing the signals through the HHT and its associated signal decomposition technique, known as empirical mode decomposition (EMD). The EMD method decomposes the vibration signals into a collection of intrinsic mode functions (IMFs). The deviations in structural integrity, measured from a healthy-state baseline, are subsequently evaluated by two damage sensitive parameters. The first is a damage index, referred to as the EM-EDI, which is established based on an energy comparison of the first or second IMF of the vibration signals, before and after occurrence of damage. The second parameter is the evaluation of the lag in instantaneous phase, a quantity derived from the HHT. In the developed methodologies, the pipe's free vibration is monitored by piezoceramic sensors and a laser Doppler vibrometer. The effectiveness of the proposed techniques is demonstrated through a set of numerical and experimental studies on a steel pipe with a mid-span girth weld, for both pressurized and nonpressurized conditions. To simulate a crack, a narrow notch is cut on one side of the girth weld. Several damage scenarios, including notches of different depths and at various locations on the pipe, are investigated. Results from both numerical and experimental studies reveal that in all damage cases the sensor located at the notch vicinity could successfully detect the notch and qualitatively predict its severity. The effect of internal pressure on the damage identification method is also monitored. Overall, the results are encouraging and promise the effectiveness of the proposed approaches as inexpensive systems for structural health monitoring purposes.

  16. Dealing with noise and physiological artifacts in human EEG recordings: empirical mode methods

    Science.gov (United States)

    Runnova, Anastasiya E.; Grubov, Vadim V.; Khramova, Marina V.; Hramov, Alexander E.

    2017-04-01

    In the paper we propose the new method for removing noise and physiological artifacts in human EEG recordings based on empirical mode decomposition (Hilbert-Huang transform). As physiological artifacts we consider specific oscillatory patterns that cause problems during EEG analysis and can be detected with additional signals recorded simultaneously with EEG (ECG, EMG, EOG, etc.) We introduce the algorithm of the proposed method with steps including empirical mode decomposition of EEG signal, choosing of empirical modes with artifacts, removing these empirical modes and reconstructing of initial EEG signal. We show the efficiency of the method on the example of filtration of human EEG signal from eye-moving artifacts.

  17. Empirical mode decomposition of the ECG signal for noise removal

    Science.gov (United States)

    Khan, Jesmin; Bhuiyan, Sharif; Murphy, Gregory; Alam, Mohammad

    2011-04-01

    Electrocardiography is a diagnostic procedure for the detection and diagnosis of heart abnormalities. The electrocardiogram (ECG) signal contains important information that is utilized by physicians for the diagnosis and analysis of heart diseases. So good quality ECG signal plays a vital role for the interpretation and identification of pathological, anatomical and physiological aspects of the whole cardiac muscle. However, the ECG signals are corrupted by noise which severely limit the utility of the recorded ECG signal for medical evaluation. The most common noise presents in the ECG signal is the high frequency noise caused by the forces acting on the electrodes. In this paper, we propose a new ECG denoising method based on the empirical mode decomposition (EMD). The proposed method is able to enhance the ECG signal upon removing the noise with minimum signal distortion. Simulation is done on the MIT-BIH database to verify the efficacy of the proposed algorithm. Experiments show that the presented method offers very good results to remove noise from the ECG signal.

  18. Empirical Mode Decomposition of the atmospheric wave field

    Directory of Open Access Journals (Sweden)

    A. J. McDonald

    2007-03-01

    Full Text Available This study examines the utility of the Empirical Mode Decomposition (EMD time-series analysis technique to separate the horizontal wind field observed by the Scott Base MF radar (78° S, 167° E into its constituent parts made up of the mean wind, gravity waves, tides, planetary waves and instrumental noise. Analysis suggests that EMD effectively separates the wind field into a set of Intrinsic Mode Functions (IMFs which can be related to atmospheric waves with different temporal scales. The Intrinsic Mode Functions resultant from application of the EMD technique to Monte-Carlo simulations of white- and red-noise processes are compared to those obtained from the measurements and are shown to be significantly different statistically. Thus, application of the EMD technique to the MF radar horizontal wind data can be used to prove that this data contains information on internal gravity waves, tides and planetary wave motions.

    Examination also suggests that the EMD technique has the ability to highlight amplitude and frequency modulations in these signals. Closer examination of one of these regions of amplitude modulation associated with dominant periods close to 12 h is suggested to be related to a wave-wave interaction between the semi-diurnal tide and a planetary wave. Application of the Hilbert transform to the IMFs forms a Hilbert-Huang spectrum which provides a way of viewing the data in a similar manner to the analysis from a continuous wavelet transform. However, the fact that the basis function of EMD is data-driven and does not need to be selected a priori is a major advantage. In addition, the skeleton diagrams, produced from the results of the Hilbert-Huang spectrum, provide a method of presentation which allows quantitative information on the instantaneous period and amplitude squared to be displayed as a function of time. Thus, it provides a novel way to view frequency and amplitude-modulated wave phenomena and potentially non

  19. Analysis of microvascular perfusion with multi-dimensional complete ensemble empirical mode decomposition with adaptive noise algorithm: Processing of laser speckle contrast images recorded in healthy subjects, at rest and during acetylcholine stimulation.

    Science.gov (United States)

    Humeau-Heurtier, Anne; Marche, Pauline; Dubois, Severine; Mahe, Guillaume

    2015-01-01

    Laser speckle contrast imaging (LSCI) is a full-field imaging modality to monitor microvascular blood flow. It is able to give images with high temporal and spatial resolutions. However, when the skin is studied, the interpretation of the bidimensional data may be difficult. This is why an averaging of the perfusion values in regions of interest is often performed and the result is followed in time, reducing the data to monodimensional time series. In order to avoid such a procedure (that leads to a loss of the spatial resolution), we propose to extract patterns from LSCI data and to compare these patterns for two physiological states in healthy subjects: at rest and at the peak of acetylcholine-induced perfusion peak. For this purpose, the recent multi-dimensional complete ensemble empirical mode decomposition with adaptive noise (MCEEMDAN) algorithm is applied to LSCI data. The results show that the intrinsic mode functions and residue given by MCEEMDAN show different patterns for the two physiological states. The images, as bidimensional data, can therefore be processed to reveal microvascular perfusion patterns, hidden in the images themselves. This work is therefore a feasibility study before analyzing data in patients with microvascular dysfunctions.

  20. Unidimensional and Bidimensional Approaches to Measuring Acculturation.

    Science.gov (United States)

    Shin, Cha-Nam; Todd, Michael; An, Kyungeh; Kim, Wonsun Sunny

    2017-08-01

    Researchers easily overlook the complexity of acculturation measurement in research. This study is to elaborate the shortcomings of unidimensional approaches to conceptualizing acculturation and highlight the importance of using bidimensional approaches in health research. We conducted a secondary data analysis on acculturation measures and eating habits obtained from 261 Korean American adults in a Midwestern city. Bidimensional approaches better conceptualized acculturation and explained more of the variance in eating habits than did unidimensional approaches. Bidimensional acculturation measures combined with appropriate analytical methods, such as a cluster analysis, are recommended in health research because they provide a more comprehensive understanding of acculturation and its association with health behaviors than do other methods.

  1. Modified complementary ensemble empirical mode decomposition and intrinsic mode functions evaluation index for high-speed train gearbox fault diagnosis

    Science.gov (United States)

    Chen, Dongyue; Lin, Jianhui; Li, Yanping

    2018-06-01

    Complementary ensemble empirical mode decomposition (CEEMD) has been developed for the mode-mixing problem in Empirical Mode Decomposition (EMD) method. Compared to the ensemble empirical mode decomposition (EEMD), the CEEMD method reduces residue noise in the signal reconstruction. Both CEEMD and EEMD need enough ensemble number to reduce the residue noise, and hence it would be too much computation cost. Moreover, the selection of intrinsic mode functions (IMFs) for further analysis usually depends on experience. A modified CEEMD method and IMFs evaluation index are proposed with the aim of reducing the computational cost and select IMFs automatically. A simulated signal and in-service high-speed train gearbox vibration signals are employed to validate the proposed method in this paper. The results demonstrate that the modified CEEMD can decompose the signal efficiently with less computation cost, and the IMFs evaluation index can select the meaningful IMFs automatically.

  2. Detrending with Empirical Mode Decomposition (DEMD): Theory, Evaluation, and Application

    Science.gov (United States)

    Bolch, Michael Adam

    Land-surface heterogeneity (LSH) at different scales has significant influence on atmospheric boundary layer (ABL) buoyant and shear turbulence generation and transfers of water, carbon and heat. The extent of proliferation of this influence into larger-scale circulations and atmospheric structures is a topic continually investigated in experimental and numerical studies, in many cases with the hopes of improving land-atmosphere parameterizations for modeling purposes. The blending height is a potential metric for the vertical propagation of LSH effects into the ABL, and has been the subject of study for several decades. Proper assessment of the efficacy of blending height theory invites the combination of observations throughout ABLs above different LSH scales with model simulations of the observed ABL and LSH conditions. The central goal of this project is to develop an apt and thoroughly scrutinized method for procuring ABL observations that are accurately detrended and justifiably relevant for such a study, referred to here as Detrending with Empirical Mode Decomposition (DEMD). The Duke University helicopter observation platform (HOP) provides ABL data [wind (u, v, and w), temperature ( T), moisture (q), and carbon dioxide (CO 2)] at a wide range of altitudes, especially in the lower ABL, where LSH effects are most prominent, and where other aircraft-based platforms cannot fly. Also, lower airspeeds translate to higher resolution of the scalars and fluxes needed to evaluate blending height theory. To confirm noninterference of the main rotor downwash with the HOP sensors, and also to identify optimal airspeeds, analytical, numerical, and observational studies are presented. Analytical analysis clears the main rotor downwash from the HOP nose at airspeeds above 10 m s-1. Numerical models find an acceptable range from 20-40 m s-1, due to a growing compressed air preceding the HOP nose. The first observational study finds no impact of different HOP airspeeds on

  3. On bidimensional Lagrangian conformal models

    International Nuclear Information System (INIS)

    Lazzarini, S.

    1990-04-01

    The main topic of this thesis is the study of Conformal Field Theories defined on an arbitrary compact Riemann surface without boundary. The Beltrami parametrization of complexe structures endowing such a surface provides a local bidimensional diffeomorphism invariance of the theory and the holomorphic factorization. The perturbative quantization a la Feynman is then constrained by local factorized Ward identities. The renormalization is analysed in the Esptein-Glaser scheme. A first part deals with the simplest free field models where one checks the interesting conjecture that renormalized perturbative expansions could be resumed by a Polyakov's formula which is a Wess-Zumino action for the diffeomorphism anomaly. For a higher genus surface, only a differential version is proposed. The second part of this thesis is devoted to the characterization of some observables of the free bosonic string in the corresponding gauge theory with the aid of the nilpotent Slavnov s-operator. It is conjectured that part of the observables of this theory is labelled by the local cohomology of s modulo d and corresponds to the vertex operators, as it is verified for the tachyon vertex in the conformal gauge [fr

  4. A Systematic Assessment of Empirical Research on Foreign Entry Mode

    DEFF Research Database (Denmark)

    Wulff, Jesper

    2016-01-01

    of dimensions. Findings Findings question the frequent use of commonly used measures (e.g. advertising intensity) and control variables (e.g. firm size) and suggest that statements about the importance of mode choice for subsidiary performance may be premature. Methodologically, this study identifies critical...... issues with regard to interpretation of interactions and the entry mode choice set. Research limitations/implications This study limits itself to study the direction of relationships and does not analyze effect sizes. Further, future research may benefit from broadening the entry mode choice by extending...

  5. Filtration of human EEG recordings from physiological artifacts with empirical mode method

    Science.gov (United States)

    Grubov, Vadim V.; Runnova, Anastasiya E.; Khramova, Marina V.

    2017-03-01

    In the paper we propose the new method for dealing with noise and physiological artifacts in experimental human EEG recordings. The method is based on analysis of EEG signals with empirical mode decomposition (Hilbert-Huang transform). We consider noises and physiological artifacts on EEG as specific oscillatory patterns that cause problems during EEG analysis and can be detected with additional signals recorded simultaneously with EEG (ECG, EMG, EOG, etc.) We introduce the algorithm of the method with following steps: empirical mode decomposition of EEG signal, choosing of empirical modes with artifacts, removing empirical modes with artifacts, reconstruction of the initial EEG signal. We test the method on filtration of experimental human EEG signals from eye-moving artifacts and show high efficiency of the method.

  6. Choice of Foreign Market Entry Mode - Cognitions from Empirical and Theoretical Studies

    OpenAIRE

    Zhao, Xuemin; Decker, Reinhold

    2004-01-01

    This paper analyzes critically five basic theories on market entry mode decision with respect to existing strengths and weaknesses and the results of corresponding empirical studies. Starting from conflictions both in theories and empirical studies dealing with the entry mode choice problem we motivate a significant need of further research in this important area of international marketing. Furthermore we provide implications for managers in practice and outline emerging trends in market entr...

  7. Improved Empirical Mode Decomposition Algorithm of Processing Complex Signal for IoT Application

    OpenAIRE

    Yang, Xianzhao; Cheng, Gengguo; Liu, Huikang

    2015-01-01

    Hilbert-Huang transform is widely used in signal analysis. However, due to its inadequacy in estimating both the maximum and the minimum values of the signals at both ends of the border, traditional HHT is easy to produce boundary error in empirical mode decomposition (EMD) process. To overcome this deficiency, this paper proposes an enhanced empirical mode decomposition algorithm for processing complex signal. Our work mainly focuses on two aspects. On one hand, we develop a technique to obt...

  8. Hybrid empirical mode decomposition- ARIMA for forecasting exchange rates

    Science.gov (United States)

    Abadan, Siti Sarah; Shabri, Ani; Ismail, Shuhaida

    2015-02-01

    This paper studied the forecasting of monthly Malaysian Ringgit (MYR)/ United State Dollar (USD) exchange rates using the hybrid of two methods which are the empirical model decomposition (EMD) and the autoregressive integrated moving average (ARIMA). MYR is pegged to USD during the Asian financial crisis causing the exchange rates are fixed to 3.800 from 2nd of September 1998 until 21st of July 2005. Thus, the chosen data in this paper is the post-July 2005 data, starting from August 2005 to July 2010. The comparative study using root mean square error (RMSE) and mean absolute error (MAE) showed that the EMD-ARIMA outperformed the single-ARIMA and the random walk benchmark model.

  9. The Fault Diagnosis of Rolling Bearing Based on Ensemble Empirical Mode Decomposition and Random Forest

    OpenAIRE

    Qin, Xiwen; Li, Qiaoling; Dong, Xiaogang; Lv, Siqi

    2017-01-01

    Accurate diagnosis of rolling bearing fault on the normal operation of machinery and equipment has a very important significance. A method combining Ensemble Empirical Mode Decomposition (EEMD) and Random Forest (RF) is proposed. Firstly, the original signal is decomposed into several intrinsic mode functions (IMFs) by EEMD, and the effective IMFs are selected. Then their energy entropy is calculated as the feature. Finally, the classification is performed by RF. In addition, the wavelet meth...

  10. Cross-validating a bidimensional mathematics anxiety scale.

    Science.gov (United States)

    Haiyan Bai

    2011-03-01

    The psychometric properties of a 14-item bidimensional Mathematics Anxiety Scale-Revised (MAS-R) were empirically cross-validated with two independent samples consisting of 647 secondary school students. An exploratory factor analysis on the scale yielded strong construct validity with a clear two-factor structure. The results from a confirmatory factor analysis indicated an excellent model-fit (χ(2) = 98.32, df = 62; normed fit index = .92, comparative fit index = .97; root mean square error of approximation = .04). The internal consistency (.85), test-retest reliability (.71), interfactor correlation (.26, p anxiety. Math anxiety, as measured by MAS-R, correlated negatively with student achievement scores (r = -.38), suggesting that MAS-R may be a useful tool for classroom teachers and other educational personnel tasked with identifying students at risk of reduced math achievement because of anxiety.

  11. Single Photon Avalanche Diodes: Towards the Large Bidimensional Arrays

    Directory of Open Access Journals (Sweden)

    Emilio Sciacca

    2008-08-01

    Full Text Available Single photon detection is one of the most challenging goals of photonics. In recent years, the study of ultra-fast and/or low-intensity phenomena has received renewed attention from the academic and industrial communities. Intense research activity has been focused on bio-imaging applications, bio-luminescence, bio-scattering methods, and, more in general, on several applications requiring high speed operation and high timing resolution. In this paper we present design and characterization of bi-dimensional arrays of a next generation of single photon avalanche diodes (SPADs. Single photon sensitivity, dark noise, afterpulsing and timing resolution of the single SPAD have been examined in several experimental conditions. Moreover, the effects arising from their integration and the readout mode have also been deeply investigated.

  12. Multi-Scale Pixel-Based Image Fusion Using Multivariate Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Naveed ur Rehman

    2015-05-01

    Full Text Available A novel scheme to perform the fusion of multiple images using the multivariate empirical mode decomposition (MEMD algorithm is proposed. Standard multi-scale fusion techniques make a priori assumptions regarding input data, whereas standard univariate empirical mode decomposition (EMD-based fusion techniques suffer from inherent mode mixing and mode misalignment issues, characterized respectively by either a single intrinsic mode function (IMF containing multiple scales or the same indexed IMFs corresponding to multiple input images carrying different frequency information. We show that MEMD overcomes these problems by being fully data adaptive and by aligning common frequency scales from multiple channels, thus enabling their comparison at a pixel level and subsequent fusion at multiple data scales. We then demonstrate the potential of the proposed scheme on a large dataset of real-world multi-exposure and multi-focus images and compare the results against those obtained from standard fusion algorithms, including the principal component analysis (PCA, discrete wavelet transform (DWT and non-subsampled contourlet transform (NCT. A variety of image fusion quality measures are employed for the objective evaluation of the proposed method. We also report the results of a hypothesis testing approach on our large image dataset to identify statistically-significant performance differences.

  13. Eliminating the zero spectrum in Fourier transform profilometry using empirical mode decomposition.

    Science.gov (United States)

    Li, Sikun; Su, Xianyu; Chen, Wenjing; Xiang, Liqun

    2009-05-01

    Empirical mode decomposition is introduced into Fourier transform profilometry to extract the zero spectrum included in the deformed fringe pattern without the need for capturing two fringe patterns with pi phase difference. The fringe pattern is subsequently demodulated using a standard Fourier transform profilometry algorithm. With this method, the deformed fringe pattern is adaptively decomposed into a finite number of intrinsic mode functions that vary from high frequency to low frequency by means of an algorithm referred to as a sifting process. Then the zero spectrum is separated from the high-frequency components effectively. Experiments validate the feasibility of this method.

  14. The Fault Diagnosis of Rolling Bearing Based on Ensemble Empirical Mode Decomposition and Random Forest

    Directory of Open Access Journals (Sweden)

    Xiwen Qin

    2017-01-01

    Full Text Available Accurate diagnosis of rolling bearing fault on the normal operation of machinery and equipment has a very important significance. A method combining Ensemble Empirical Mode Decomposition (EEMD and Random Forest (RF is proposed. Firstly, the original signal is decomposed into several intrinsic mode functions (IMFs by EEMD, and the effective IMFs are selected. Then their energy entropy is calculated as the feature. Finally, the classification is performed by RF. In addition, the wavelet method is also used in the proposed process, the same as EEMD. The results of the comparison show that the EEMD method is more accurate than the wavelet method.

  15. Tourism forecasting using modified empirical mode decomposition and group method of data handling

    Science.gov (United States)

    Yahya, N. A.; Samsudin, R.; Shabri, A.

    2017-09-01

    In this study, a hybrid model using modified Empirical Mode Decomposition (EMD) and Group Method of Data Handling (GMDH) model is proposed for tourism forecasting. This approach reconstructs intrinsic mode functions (IMFs) produced by EMD using trial and error method. The new component and the remaining IMFs is then predicted respectively using GMDH model. Finally, the forecasted results for each component are aggregated to construct an ensemble forecast. The data used in this experiment are monthly time series data of tourist arrivals from China, Thailand and India to Malaysia from year 2000 to 2016. The performance of the model is evaluated using Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE) where conventional GMDH model and EMD-GMDH model are used as benchmark models. Empirical results proved that the proposed model performed better forecasts than the benchmarked models.

  16. On the rational approximation of the bidimensional potentials

    International Nuclear Information System (INIS)

    Niculescu, V.I.R; Catana, D.

    1997-01-01

    In the present letter we introduced a symmetrical bidimensional potential with Woods-Saxon tail. The potential approximation has permitted to replace in the matrix the evaluation of double integration by a product of two integrals. That implied a complexity reduction in the Hamiltonian eigenvalue and eigenvector evaluation. Also, the harmonic bidimensional basis simplifies significantly the evaluation of electric multipole operators. (authors)

  17. Integrated ensemble noise-reconstructed empirical mode decomposition for mechanical fault detection

    Science.gov (United States)

    Yuan, Jing; Ji, Feng; Gao, Yuan; Zhu, Jun; Wei, Chenjun; Zhou, Yu

    2018-05-01

    A new branch of fault detection is utilizing the noise such as enhancing, adding or estimating the noise so as to improve the signal-to-noise ratio (SNR) and extract the fault signatures. Hereinto, ensemble noise-reconstructed empirical mode decomposition (ENEMD) is a novel noise utilization method to ameliorate the mode mixing and denoised the intrinsic mode functions (IMFs). Despite the possibility of superior performance in detecting weak and multiple faults, the method still suffers from the major problems of the user-defined parameter and the powerless capability for a high SNR case. Hence, integrated ensemble noise-reconstructed empirical mode decomposition is proposed to overcome the drawbacks, improved by two noise estimation techniques for different SNRs as well as the noise estimation strategy. Independent from the artificial setup, the noise estimation by the minimax thresholding is improved for a low SNR case, which especially shows an outstanding interpretation for signature enhancement. For approximating the weak noise precisely, the noise estimation by the local reconfiguration using singular value decomposition (SVD) is proposed for a high SNR case, which is particularly powerful for reducing the mode mixing. Thereinto, the sliding window for projecting the phase space is optimally designed by the correlation minimization. Meanwhile, the reasonable singular order for the local reconfiguration to estimate the noise is determined by the inflection point of the increment trend of normalized singular entropy. Furthermore, the noise estimation strategy, i.e. the selection approaches of the two estimation techniques along with the critical case, is developed and discussed for different SNRs by means of the possible noise-only IMF family. The method is validated by the repeatable simulations to demonstrate the synthetical performance and especially confirm the capability of noise estimation. Finally, the method is applied to detect the local wear fault

  18. Minimizing the trend effect on detrended cross-correlation analysis with empirical mode decomposition

    International Nuclear Information System (INIS)

    Zhao Xiaojun; Shang Pengjian; Zhao Chuang; Wang Jing; Tao Rui

    2012-01-01

    Highlights: ► Investigate the effects of linear, exponential and periodic trends on DCCA. ► Apply empirical mode decomposition to extract trend term. ► Strong and monotonic trends are successfully eliminated. ► Get the cross-correlation exponent in a persistent behavior without crossover. - Abstract: Detrended cross-correlation analysis (DCCA) is a scaling method commonly used to estimate long-range power law cross-correlation in non-stationary signals. However, the susceptibility of DCCA to trends makes the scaling results difficult to analyze due to spurious crossovers. We artificially generate long-range cross-correlated signals and systematically investigate the effect of linear, exponential and periodic trends. Specifically to the crossovers raised by trends, we apply empirical mode decomposition method which decomposes underlying signals into several intrinsic mode functions (IMF) and a residual trend. After the removal of residual term, strong and monotonic trends such as linear and exponential trends are successfully eliminated. But periodic trend cannot be separated out according to the criterion of IMF, which can be eliminated by Fourier transform. As a special case of DCCA, detrended fluctuation analysis presents similar results.

  19. Determination of knock characteristics in spark ignition engines: an approach based on ensemble empirical mode decomposition

    International Nuclear Information System (INIS)

    Li, Ning; Liang, Caiping; Yang, Jianguo; Zhou, Rui

    2016-01-01

    Knock is one of the major constraints to improve the performance and thermal efficiency of spark ignition (SI) engines. It can also result in severe permanent engine damage under certain operating conditions. Based on the ensemble empirical mode decomposition (EEMD), this paper proposes a new approach to determine the knock characteristics in SI engines. By adding a uniformly distributed and finite white Gaussian noise, the EEMD can preserve signal continuity in different scales and therefore alleviates the mode-mixing problem occurring in the classic empirical mode decomposition (EMD). The feasibilities of applying the EEMD to detect the knock signatures of a test SI engine via the pressure signal measured from combustion chamber and the vibration signal measured from cylinder head are investigated. Experimental results show that the EEMD-based method is able to detect the knock signatures from both the pressure signal and vibration signal, even in initial stage of knock. Finally, by comparing the application results with those obtained by short-time Fourier transform (STFT), Wigner–Ville distribution (WVD) and discrete wavelet transform (DWT), the superiority of the EEMD method in determining knock characteristics is demonstrated. (paper)

  20. A new approach for crude oil price analysis based on empirical mode decomposition

    International Nuclear Information System (INIS)

    Zhang, Xun; Wang, Shou-Yang; Lai, K.K.

    2008-01-01

    The importance of understanding the underlying characteristics of international crude oil price movements attracts much attention from academic researchers and business practitioners. Due to the intrinsic complexity of the oil market, however, most of them fail to produce consistently good results. Empirical Mode Decomposition (EMD), recently proposed by Huang et al., appears to be a novel data analysis method for nonlinear and non-stationary time series. By decomposing a time series into a small number of independent and concretely implicational intrinsic modes based on scale separation, EMD explains the generation of time series data from a novel perspective. Ensemble EMD (EEMD) is a substantial improvement of EMD which can better separate the scales naturally by adding white noise series to the original time series and then treating the ensemble averages as the true intrinsic modes. In this paper, we extend EEMD to crude oil price analysis. First, three crude oil price series with different time ranges and frequencies are decomposed into several independent intrinsic modes, from high to low frequency. Second, the intrinsic modes are composed into a fluctuating process, a slowly varying part and a trend based on fine-to-coarse reconstruction. The economic meanings of the three components are identified as short term fluctuations caused by normal supply-demand disequilibrium or some other market activities, the effect of a shock of a significant event, and a long term trend. Finally, the EEMD is shown to be a vital technique for crude oil price analysis. (author)

  1. Support Vector Regression Model Based on Empirical Mode Decomposition and Auto Regression for Electric Load Forecasting

    Directory of Open Access Journals (Sweden)

    Hong-Juan Li

    2013-04-01

    Full Text Available Electric load forecasting is an important issue for a power utility, associated with the management of daily operations such as energy transfer scheduling, unit commitment, and load dispatch. Inspired by strong non-linear learning capability of support vector regression (SVR, this paper presents a SVR model hybridized with the empirical mode decomposition (EMD method and auto regression (AR for electric load forecasting. The electric load data of the New South Wales (Australia market are employed for comparing the forecasting performances of different forecasting models. The results confirm the validity of the idea that the proposed model can simultaneously provide forecasting with good accuracy and interpretability.

  2. Application of empirical mode decomposition with local linear quantile regression in financial time series forecasting.

    Science.gov (United States)

    Jaber, Abobaker M; Ismail, Mohd Tahir; Altaher, Alsaidi M

    2014-01-01

    This paper mainly forecasts the daily closing price of stock markets. We propose a two-stage technique that combines the empirical mode decomposition (EMD) with nonparametric methods of local linear quantile (LLQ). We use the proposed technique, EMD-LLQ, to forecast two stock index time series. Detailed experiments are implemented for the proposed method, in which EMD-LPQ, EMD, and Holt-Winter methods are compared. The proposed EMD-LPQ model is determined to be superior to the EMD and Holt-Winter methods in predicting the stock closing prices.

  3. Ensemble empirical mode decomposition based fluorescence spectral noise reduction for low concentration PAHs

    Science.gov (United States)

    Wang, Shu-tao; Yang, Xue-ying; Kong, De-ming; Wang, Yu-tian

    2017-11-01

    A new noise reduction method based on ensemble empirical mode decomposition (EEMD) is proposed to improve the detection effect for fluorescence spectra. Polycyclic aromatic hydrocarbons (PAHs) pollutants, as a kind of important current environmental pollution source, are highly oncogenic. Using the fluorescence spectroscopy method, the PAHs pollutants can be detected. However, instrument will produce noise in the experiment. Weak fluorescent signals can be affected by noise, so we propose a way to denoise and improve the detection effect. Firstly, we use fluorescence spectrometer to detect PAHs to obtain fluorescence spectra. Subsequently, noises are reduced by EEMD algorithm. Finally, the experiment results show the proposed method is feasible.

  4. Noise-assisted data processing with empirical mode decomposition in biomedical signals.

    Science.gov (United States)

    Karagiannis, Alexandros; Constantinou, Philip

    2011-01-01

    In this paper, a methodology is described in order to investigate the performance of empirical mode decomposition (EMD) in biomedical signals, and especially in the case of electrocardiogram (ECG). Synthetic ECG signals corrupted with white Gaussian noise are employed and time series of various lengths are processed with EMD in order to extract the intrinsic mode functions (IMFs). A statistical significance test is implemented for the identification of IMFs with high-level noise components and their exclusion from denoising procedures. Simulation campaign results reveal that a decrease of processing time is accomplished with the introduction of preprocessing stage, prior to the application of EMD in biomedical time series. Furthermore, the variation in the number of IMFs according to the type of the preprocessing stage is studied as a function of SNR and time-series length. The application of the methodology in MIT-BIH ECG records is also presented in order to verify the findings in real ECG signals.

  5. The use of the empirical mode decomposition for the identification of mean field aligned reference frames

    Directory of Open Access Journals (Sweden)

    Mauro Regi

    2017-01-01

    Full Text Available The magnetic field satellite data are usually referred to geocentric coordinate reference frame. Conversely, the magnetohydrodynamic waves modes in magnetized plasma depend on the ambient magnetic field, and is then useful to rotate the magnetic field measurements into the mean field aligned (MFA coordinate system. This reference frame is useful to study the ultra low frequency magnetic field variations along the direction of the mean field and perpendicularly to it. In order to identify the mean magnetic field the classical moving average (MAVG approach is usually adopted but, under particular conditions, this procedure induces undesired features, such as spectral alteration in the rotated components. We discuss these aspects promoting an alternative and more efficient method for mean field aligned projection, based on the empirical mode decomposition (EMD.

  6. A Novel Empirical Mode Decomposition With Support Vector Regression for Wind Speed Forecasting.

    Science.gov (United States)

    Ren, Ye; Suganthan, Ponnuthurai Nagaratnam; Srikanth, Narasimalu

    2016-08-01

    Wind energy is a clean and an abundant renewable energy source. Accurate wind speed forecasting is essential for power dispatch planning, unit commitment decision, maintenance scheduling, and regulation. However, wind is intermittent and wind speed is difficult to predict. This brief proposes a novel wind speed forecasting method by integrating empirical mode decomposition (EMD) and support vector regression (SVR) methods. The EMD is used to decompose the wind speed time series into several intrinsic mode functions (IMFs) and a residue. Subsequently, a vector combining one historical data from each IMF and the residue is generated to train the SVR. The proposed EMD-SVR model is evaluated with a wind speed data set. The proposed EMD-SVR model outperforms several recently reported methods with respect to accuracy or computational complexity.

  7. Denoising of chaotic signal using independent component analysis and empirical mode decomposition with circulate translating

    International Nuclear Information System (INIS)

    Wang Wen-Bo; Zhang Xiao-Dong; Chang Yuchan; Wang Xiang-Li; Wang Zhao; Chen Xi; Zheng Lei

    2016-01-01

    In this paper, a new method to reduce noises within chaotic signals based on ICA (independent component analysis) and EMD (empirical mode decomposition) is proposed. The basic idea is decomposing chaotic signals and constructing multidimensional input vectors, firstly, on the base of EMD and its translation invariance. Secondly, it makes the independent component analysis on the input vectors, which means that a self adapting denoising is carried out for the intrinsic mode functions (IMFs) of chaotic signals. Finally, all IMFs compose the new denoised chaotic signal. Experiments on the Lorenz chaotic signal composed of different Gaussian noises and the monthly observed chaotic sequence on sunspots were put into practice. The results proved that the method proposed in this paper is effective in denoising of chaotic signals. Moreover, it can correct the center point in the phase space effectively, which makes it approach the real track of the chaotic attractor. (paper)

  8. Fringe-projection profilometry based on two-dimensional empirical mode decomposition.

    Science.gov (United States)

    Zheng, Suzhen; Cao, Yiping

    2013-11-01

    In 3D shape measurement, because deformed fringes often contain low-frequency information degraded with random noise and background intensity information, a new fringe-projection profilometry is proposed based on 2D empirical mode decomposition (2D-EMD). The fringe pattern is first decomposed into numbers of intrinsic mode functions by 2D-EMD. Because the method has partial noise reduction, the background components can be removed to obtain the fundamental components needed to perform Hilbert transformation to retrieve the phase information. The 2D-EMD can effectively extract the modulation phase of a single direction fringe and an inclined fringe pattern because it is a full 2D analysis method and considers the relationship between adjacent lines of a fringe patterns. In addition, as the method does not add noise repeatedly, as does ensemble EMD, the data processing time is shortened. Computer simulations and experiments prove the feasibility of this method.

  9. Application of empirical mode decomposition method for characterization of random vibration signals

    Directory of Open Access Journals (Sweden)

    Setyamartana Parman

    2016-07-01

    Full Text Available Characterization of finite measured signals is a great of importance in dynamical modeling and system identification. This paper addresses an approach for characterization of measured random vibration signals where the approach rests on a method called empirical mode decomposition (EMD. The applicability of proposed approach is tested in one numerical and experimental data from a structural system, namely spar platform. The results are three main signal components, comprising: noise embedded in the measured signal as the first component, first intrinsic mode function (IMF called as the wave frequency response (WFR as the second component and second IMF called as the low frequency response (LFR as the third component while the residue is the trend. Band-pass filter (BPF method is taken as benchmark for the results obtained from EMD method.

  10. An epileptic seizures detection algorithm based on the empirical mode decomposition of EEG.

    Science.gov (United States)

    Orosco, Lorena; Laciar, Eric; Correa, Agustina Garces; Torres, Abel; Graffigna, Juan P

    2009-01-01

    Epilepsy is a neurological disorder that affects around 50 million people worldwide. The seizure detection is an important component in the diagnosis of epilepsy. In this study, the Empirical Mode Decomposition (EMD) method was proposed on the development of an automatic epileptic seizure detection algorithm. The algorithm first computes the Intrinsic Mode Functions (IMFs) of EEG records, then calculates the energy of each IMF and performs the detection based on an energy threshold and a minimum duration decision. The algorithm was tested in 9 invasive EEG records provided and validated by the Epilepsy Center of the University Hospital of Freiburg. In 90 segments analyzed (39 with epileptic seizures) the sensitivity and specificity obtained with the method were of 56.41% and 75.86% respectively. It could be concluded that EMD is a promissory method for epileptic seizure detection in EEG records.

  11. Tissue artifact removal from respiratory signals based on empirical mode decomposition.

    Science.gov (United States)

    Liu, Shaopeng; Gao, Robert X; John, Dinesh; Staudenmayer, John; Freedson, Patty

    2013-05-01

    On-line measurement of respiration plays an important role in monitoring human physical activities. Such measurement commonly employs sensing belts secured around the rib cage and abdomen of the test object. Affected by the movement of body tissues, respiratory signals typically have a low signal-to-noise ratio. Removing tissue artifacts therefore is critical to ensuring effective respiration analysis. This paper presents a signal decomposition technique for tissue artifact removal from respiratory signals, based on the empirical mode decomposition (EMD). An algorithm based on the mutual information and power criteria was devised to automatically select appropriate intrinsic mode functions for tissue artifact removal and respiratory signal reconstruction. Performance of the EMD-algorithm was evaluated through simulations and real-life experiments (N = 105). Comparison with low-pass filtering that has been conventionally applied confirmed the effectiveness of the technique in tissue artifacts removal.

  12. A Frequency-Weighted Energy Operator and complementary ensemble empirical mode decomposition for bearing fault detection

    Science.gov (United States)

    Imaouchen, Yacine; Kedadouche, Mourad; Alkama, Rezak; Thomas, Marc

    2017-01-01

    Signal processing techniques for non-stationary and noisy signals have recently attracted considerable attentions. Among them, the empirical mode decomposition (EMD) which is an adaptive and efficient method for decomposing signals from high to low frequencies into intrinsic mode functions (IMFs). Ensemble EMD (EEMD) is proposed to overcome the mode mixing problem of the EMD. In the present paper, the Complementary EEMD (CEEMD) is used for bearing fault detection. As a noise-improved method, the CEEMD not only overcomes the mode mixing, but also eliminates the residual of added white noise persisting into the IMFs and enhance the calculation efficiency of the EEMD method. Afterward, a selection method is developed to choose relevant IMFs containing information about defects. Subsequently, a signal is reconstructed from the sum of relevant IMFs and a Frequency-Weighted Energy Operator is tailored to extract both the amplitude and frequency modulations from the selected IMFs. This operator outperforms the conventional energy operator and the enveloping methods, especially in the presence of strong noise and multiple vibration interferences. Furthermore, simulation and experimental results showed that the proposed method improves performances for detecting the bearing faults. The method has also high computational efficiency and is able to detect the fault at an early stage of degradation.

  13. A hybrid filtering method based on a novel empirical mode decomposition for friction signals

    International Nuclear Information System (INIS)

    Li, Chengwei; Zhan, Liwei

    2015-01-01

    During a measurement, the measured signal usually contains noise. To remove the noise and preserve the important feature of the signal, we introduce a hybrid filtering method that uses a new intrinsic mode function (NIMF) and a modified Hausdorff distance. The NIMF is defined as the difference between the noisy signal and each intrinsic mode function (IMF), which is obtained by empirical mode decomposition (EMD), ensemble EMD, complementary ensemble EMD, or complete ensemble EMD with adaptive noise (CEEMDAN). The relevant mode selecting is based on the similarity between the first NIMF and the rest of the NIMFs. With this filtering method, the EMD and improved versions are used to filter the simulation and friction signals. The friction signal between an airplane tire and the runaway is recorded during a simulated airplane touchdown and features spikes of various amplitudes and noise. The filtering effectiveness of the four hybrid filtering methods are compared and discussed. The results show that the filtering method based on CEEMDAN outperforms other signal filtering methods. (paper)

  14. Recognizing of stereotypic patterns in epileptic EEG using empirical modes and wavelets

    Science.gov (United States)

    Grubov, V. V.; Sitnikova, E.; Pavlov, A. N.; Koronovskii, A. A.; Hramov, A. E.

    2017-11-01

    Epileptic activity in the form of spike-wave discharges (SWD) appears in the electroencephalogram (EEG) during absence seizures. This paper evaluates two approaches for detecting stereotypic rhythmic activities in EEG, i.e., the continuous wavelet transform (CWT) and the empirical mode decomposition (EMD). The CWT is a well-known method of time-frequency analysis of EEG, whereas EMD is a relatively novel approach for extracting signal's waveforms. A new method for pattern recognition based on combination of CWT and EMD is proposed. It was found that this combined approach resulted to the sensitivity of 86.5% and specificity of 92.9% for sleep spindles and 97.6% and 93.2% for SWD, correspondingly. Considering strong within- and between-subjects variability of sleep spindles, the obtained efficiency in their detection was high in comparison with other methods based on CWT. It is concluded that the combination of a wavelet-based approach and empirical modes increases the quality of automatic detection of stereotypic patterns in rat's EEG.

  15. Empirical mode decomposition and k-nearest embedding vectors for timely analyses of antibiotic resistance trends.

    Science.gov (United States)

    Teodoro, Douglas; Lovis, Christian

    2013-01-01

    Antibiotic resistance is a major worldwide public health concern. In clinical settings, timely antibiotic resistance information is key for care providers as it allows appropriate targeted treatment or improved empirical treatment when the specific results of the patient are not yet available. To improve antibiotic resistance trend analysis algorithms by building a novel, fully data-driven forecasting method from the combination of trend extraction and machine learning models for enhanced biosurveillance systems. We investigate a robust model for extraction and forecasting of antibiotic resistance trends using a decade of microbiology data. Our method consists of breaking down the resistance time series into independent oscillatory components via the empirical mode decomposition technique. The resulting waveforms describing intrinsic resistance trends serve as the input for the forecasting algorithm. The algorithm applies the delay coordinate embedding theorem together with the k-nearest neighbor framework to project mappings from past events into the future dimension and estimate the resistance levels. The algorithms that decompose the resistance time series and filter out high frequency components showed statistically significant performance improvements in comparison with a benchmark random walk model. We present further qualitative use-cases of antibiotic resistance trend extraction, where empirical mode decomposition was applied to highlight the specificities of the resistance trends. The decomposition of the raw signal was found not only to yield valuable insight into the resistance evolution, but also to produce novel models of resistance forecasters with boosted prediction performance, which could be utilized as a complementary method in the analysis of antibiotic resistance trends.

  16. Fast multidimensional ensemble empirical mode decomposition for the analysis of big spatio-temporal datasets.

    Science.gov (United States)

    Wu, Zhaohua; Feng, Jiaxin; Qiao, Fangli; Tan, Zhe-Min

    2016-04-13

    In this big data era, it is more urgent than ever to solve two major issues: (i) fast data transmission methods that can facilitate access to data from non-local sources and (ii) fast and efficient data analysis methods that can reveal the key information from the available data for particular purposes. Although approaches in different fields to address these two questions may differ significantly, the common part must involve data compression techniques and a fast algorithm. This paper introduces the recently developed adaptive and spatio-temporally local analysis method, namely the fast multidimensional ensemble empirical mode decomposition (MEEMD), for the analysis of a large spatio-temporal dataset. The original MEEMD uses ensemble empirical mode decomposition to decompose time series at each spatial grid and then pieces together the temporal-spatial evolution of climate variability and change on naturally separated timescales, which is computationally expensive. By taking advantage of the high efficiency of the expression using principal component analysis/empirical orthogonal function analysis for spatio-temporally coherent data, we design a lossy compression method for climate data to facilitate its non-local transmission. We also explain the basic principles behind the fast MEEMD through decomposing principal components instead of original grid-wise time series to speed up computation of MEEMD. Using a typical climate dataset as an example, we demonstrate that our newly designed methods can (i) compress data with a compression rate of one to two orders; and (ii) speed-up the MEEMD algorithm by one to two orders. © 2016 The Authors.

  17. Phase space interrogation of the empirical response modes for seismically excited structures

    Science.gov (United States)

    Paul, Bibhas; George, Riya C.; Mishra, Sudib K.

    2017-07-01

    Conventional Phase Space Interrogation (PSI) for structural damage assessment relies on exciting the structure with low dimensional chaotic waveform, thereby, significantly limiting their applicability to large structures. The PSI technique is presently extended for structure subjected to seismic excitations. The high dimensionality of the phase space for seismic response(s) are overcome by the Empirical Mode Decomposition (EMD), decomposing the responses to a number of intrinsic low dimensional oscillatory modes, referred as Intrinsic Mode Functions (IMFs). Along with their low dimensionality, a few IMFs, retain sufficient information of the system dynamics to reflect the damage induced changes. The mutually conflicting nature of low-dimensionality and the sufficiency of dynamic information are taken care by the optimal choice of the IMF(s), which is shown to be the third/fourth IMFs. The optimal IMF(s) are employed for the reconstruction of the Phase space attractor following Taken's embedding theorem. The widely referred Changes in Phase Space Topology (CPST) feature is then employed on these Phase portrait(s) to derive the damage sensitive feature, referred as the CPST of the IMFs (CPST-IMF). The legitimacy of the CPST-IMF is established as a damage sensitive feature by assessing its variation with a number of damage scenarios benchmarked in the IASC-ASCE building. The damage localization capability, remarkable tolerance to noise contamination and the robustness under different seismic excitations of the feature are demonstrated.

  18. Functionalization and Self-Assembly of DNA Bidimensional Arrays

    Directory of Open Access Journals (Sweden)

    Ramon Eritja

    2011-09-01

    Full Text Available Oligonucleotides carrying amino, thiol groups, as well as fluorescein, c-myc peptide sequence and nanogold at internal positions were prepared and used for the assembly of bidimensional DNA arrays.

  19. Turbulent Statistics From Time-Resolved PIV Measurements of a Jet Using Empirical Mode Decomposition

    Science.gov (United States)

    Dahl, Milo D.

    2013-01-01

    Empirical mode decomposition is an adaptive signal processing method that when applied to a broadband signal, such as that generated by turbulence, acts as a set of band-pass filters. This process was applied to data from time-resolved, particle image velocimetry measurements of subsonic jets prior to computing the second-order, two-point, space-time correlations from which turbulent phase velocities and length and time scales could be determined. The application of this method to large sets of simultaneous time histories is new. In this initial study, the results are relevant to acoustic analogy source models for jet noise prediction. The high frequency portion of the results could provide the turbulent values for subgrid scale models for noise that is missed in large-eddy simulations. The results are also used to infer that the cross-correlations between different components of the decomposed signals at two points in space, neglected in this initial study, are important.

  20. Effect of tidal triggering on seismicity in Taiwan revealed by the empirical mode decomposition method

    Directory of Open Access Journals (Sweden)

    H.-J. Chen

    2012-07-01

    Full Text Available The effect of tidal triggering on earthquake occurrence has been controversial for many years. This study considered earthquakes that occurred near Taiwan between 1973 and 2008. Because earthquake data are nonlinear and non-stationary, we applied the empirical mode decomposition (EMD method to analyze the temporal variations in the number of daily earthquakes to investigate the effect of tidal triggering. We compared the results obtained from the non-declustered catalog with those from two kinds of declustered catalogs and discuss the aftershock effect on the EMD-based analysis. We also investigated stacking the data based on in-phase phenomena of theoretical Earth tides with statistical significance tests. Our results show that the effects of tidal triggering, particularly the lunar tidal effect, can be extracted from the raw seismicity data using the approach proposed here. Our results suggest that the lunar tidal force is likely a factor in the triggering of earthquakes.

  1. Reduction of heart sound interference from lung sound signals using empirical mode decomposition technique.

    Science.gov (United States)

    Mondal, Ashok; Bhattacharya, P S; Saha, Goutam

    2011-01-01

    During the recording time of lung sound (LS) signals from the chest wall of a subject, there is always heart sound (HS) signal interfering with it. This obscures the features of lung sound signals and creates confusion on pathological states, if any, of the lungs. A novel method based on empirical mode decomposition (EMD) technique is proposed in this paper for reducing the undesired heart sound interference from the desired lung sound signals. In this, the mixed signal is split into several components. Some of these components contain larger proportions of interfering signals like heart sound, environmental noise etc. and are filtered out. Experiments have been conducted on simulated and real-time recorded mixed signals of heart sound and lung sound. The proposed method is found to be superior in terms of time domain, frequency domain, and time-frequency domain representations and also in listening test performed by pulmonologist.

  2. Multiband Prediction Model for Financial Time Series with Multivariate Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Md. Rabiul Islam

    2012-01-01

    Full Text Available This paper presents a subband approach to financial time series prediction. Multivariate empirical mode decomposition (MEMD is employed here for multiband representation of multichannel financial time series together. Autoregressive moving average (ARMA model is used in prediction of individual subband of any time series data. Then all the predicted subband signals are summed up to obtain the overall prediction. The ARMA model works better for stationary signal. With multiband representation, each subband becomes a band-limited (narrow band signal and hence better prediction is achieved. The performance of the proposed MEMD-ARMA model is compared with classical EMD, discrete wavelet transform (DWT, and with full band ARMA model in terms of signal-to-noise ratio (SNR and mean square error (MSE between the original and predicted time series. The simulation results show that the MEMD-ARMA-based method performs better than the other methods.

  3. Empirical mode decomposition and Hilbert transforms for analysis of oil-film interferograms

    International Nuclear Information System (INIS)

    Chauhan, Kapil; Ng, Henry C H; Marusic, Ivan

    2010-01-01

    Oil-film interferometry is rapidly becoming the preferred method for direct measurement of wall shear stress in studies of wall-bounded turbulent flows. Although being widely accepted as the most accurate technique, it does have inherent measurement uncertainties, one of which is associated with determining the fringe spacing. This is the focus of this paper. Conventional analysis methods involve a certain level of user input and thus some subjectivity. In this paper, we consider empirical mode decomposition (EMD) and the Hilbert transform as an alternative tool for analyzing oil-film interferograms. In contrast to the commonly used Fourier-based techniques, this new method is less subjective and, as it is based on the Hilbert transform, is superior for treating amplitude and frequency modulated data. This makes it particularly robust to wide differences in the quality of interferograms

  4. Investigation of Kelvin wave periods during Hai-Tang typhoon using Empirical Mode Decomposition

    Science.gov (United States)

    Kishore, P.; Jayalakshmi, J.; Lin, Pay-Liam; Velicogna, Isabella; Sutterley, Tyler C.; Ciracì, Enrico; Mohajerani, Yara; Kumar, S. Balaji

    2017-11-01

    Equatorial Kelvin waves (KWs) are fundamental components of the tropical climate system. In this study, we investigate Kelvin waves (KWs) during the Hai-Tang typhoon of 2005 using Empirical Mode Decomposition (EMD) of regional precipitation, zonal and meridional winds. For the analysis, we use daily precipitation datasets from the Global Precipitation Climatology Project (GPCP) and wind datasets from the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-analysis (ERA-Interim). As an additional measurement, we use in-situ precipitation datasets from rain-gauges over the Taiwan region. The maximum accumulated precipitation was approximately 2400 mm during the period July 17-21, 2005 over the southwestern region of Taiwan. The spectral analysis using the wind speed at 950 hPa found in the 2nd, 3rd, and 4th intrinsic mode functions (IMFs) reveals prevailing Kelvin wave periods of ∼3 days, ∼4-6 days, and ∼6-10 days, respectively. From our analysis of precipitation datasets, we found the Kelvin waves oscillated with periods between ∼8 and 20 days.

  5. Hour-Ahead Wind Speed and Power Forecasting Using Empirical Mode Decomposition

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    Ying-Yi Hong

    2013-11-01

    Full Text Available Operation of wind power generation in a large farm is quite challenging in a smart grid owing to uncertain weather conditions. Consequently, operators must accurately forecast wind speed/power in the dispatch center to carry out unit commitment, real power scheduling and economic dispatch. This work presents a novel method based on the integration of empirical mode decomposition (EMD with artificial neural networks (ANN to forecast the short-term (1 h ahead wind speed/power. First, significant parameters for training the ANN are identified using the correlation coefficients. These significant parameters serve as inputs of the ANN. Owing to the volatile and intermittent wind speed/power, the historical time series of wind speed/power is decomposed into several intrinsic mode functions (IMFs and a residual function through EMD. Each IMF becomes less volatile and therefore increases the accuracy of the neural network. The final forecasting results are achieved by aggregating all individual forecasting results from all IMFs and their corresponding residual functions. Real data related to the wind speed and wind power measured at a wind-turbine generator in Taiwan are used for simulation. The wind speed forecasting and wind power forecasting for the four seasons are studied. Comparative studies between the proposed method and traditional methods (i.e., artificial neural network without EMD, autoregressive integrated moving average (ARIMA, and persistence method are also introduced.

  6. Correlation of Respiratory Signals and Electrocardiogram Signals via Empirical Mode Decomposition

    KAUST Repository

    El Fiky, Ahmed Osama

    2011-05-24

    Recently Electrocardiogram (ECG) signals are being broadly used as an essential diagnosing tool in different clinical applications as they carry a reliable representation not only for cardiac activities, but also for other associated biological processes, like respiration. However, the process of recording and collecting them has usually suffered from the presence of some undesired noises, which in turn affects the reliability of such representations.Therefore, de-noising ECG signals became a hot research field for signal processing experts to ensure better and clear representation of the different cardiac activities. Given the nonlinear and non-stationary properties of ECGs, it is not a simple task to cancel the undesired noise terms without affecting the biological physics of them. In this study, we are interested in correlating the ECG signals with respiratory parameters, specifically the lung volume and lung pressure. We have focused on the concept of de-noising ECG signals by means of signal decomposition using an algorithm called the Empirical Mode Decomposition (EMD) where the original ECG signals are being decomposed into a set of intrinsic mode functions (IMF). Then, we have provided criteria based on which some of these IMFs have been adapted to reconstruct de-noised ECG version. Finally, we have utilized de-noised ECGs as well as IMFs for to study the correlation with lung volume and lung pressure. These correlation studies have showed some clear resemblance especially between the oscillations of ECGs and lung pressures.

  7. Analyzing the locomotory gaitprint of Caenorhabditis elegans on the basis of empirical mode decomposition.

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    Li-Chun Lin

    Full Text Available The locomotory gait analysis of the microswimmer, Caenorhabditis elegans, is a commonly adopted approach for strain recognition and examination of phenotypic defects. Gait is also a visible behavioral expression of worms under external stimuli. This study developed an adaptive data analysis method based on empirical mode decomposition (EMD to reveal the biological cues behind intricate motion. The method was used to classify the strains of worms according to their gaitprints (i.e., phenotypic traits of locomotion. First, a norm of the locomotory pattern was created from the worm of interest. The body curvature of the worm was decomposed into four intrinsic mode functions (IMFs. A radar chart showing correlations between the predefined database and measured worm was then obtained by dividing each IMF into three parts, namely, head, mid-body, and tail. A comprehensive resemblance score was estimated after k-means clustering. Simulated data that use sinusoidal waves were generated to assess the feasibility of the algorithm. Results suggested that temporal frequency is the major factor in the process. In practice, five worm strains, including wild-type N2, TJ356 (zIs356, CL2070 (dvIs70, CB0061 (dpy-5, and CL2120 (dvIs14, were investigated. The overall classification accuracy of the gaitprint analyses of all the strains reached nearly 89%. The method can also be extended to classify some motor neuron-related locomotory defects of C. elegans in the same fashion.

  8. Analysis of respiratory mechanomyographic signals by means of the empirical mode decomposition

    International Nuclear Information System (INIS)

    Torres, A; Jane, R; Fiz, J A; Laciar, E; Galdiz, J B; Gea, J; Morera, J

    2007-01-01

    The study of the mechanomyographic (MMG) signals of respiratory muscles is a promising technique in order to evaluate the respiratory muscles effort. A critical point in MMG studies is the selection of the cut-off frequency in order to separate the low frequency (LF) component (basically due to gross movement of the muscle or of the body) and the high frequency (HF) component (related with the vibration of the muscle fibres during contraction). In this study, we propose to use the Empirical Mode Decomposition method in order to analyze the Intrinsic Mode Functions of MMG signals of the diaphragm muscle, acquired by means of a capacitive accelerometer applied on the costal wall. The method was tested on an animal model, with two incremental respiratory protocols performed by two non anesthetized mongrel dogs. The proposed EMD based method seems to be a useful tool to eliminate the low frequency component of MMG signals. The obtained correlation coefficients between respiratory and MMG parameters were higher than the ones obtained with a Wavelet multiresolution decomposition method utilized in a previous work

  9. Improved Prediction of Preterm Delivery Using Empirical Mode Decomposition Analysis of Uterine Electromyography Signals.

    Directory of Open Access Journals (Sweden)

    Peng Ren

    Full Text Available Preterm delivery increases the risk of infant mortality and morbidity, and therefore developing reliable methods for predicting its likelihood are of great importance. Previous work using uterine electromyography (EMG recordings has shown that they may provide a promising and objective way for predicting risk of preterm delivery. However, to date attempts at utilizing computational approaches to achieve sufficient predictive confidence, in terms of area under the curve (AUC values, have not achieved the high discrimination accuracy that a clinical application requires. In our study, we propose a new analytical approach for assessing the risk of preterm delivery using EMG recordings which firstly employs Empirical Mode Decomposition (EMD to obtain their Intrinsic Mode Functions (IMF. Next, the entropy values of both instantaneous amplitude and instantaneous frequency of the first ten IMF components are computed in order to derive ratios of these two distinct components as features. Discrimination accuracy of this approach compared to those proposed previously was then calculated using six differently representative classifiers. Finally, three different electrode positions were analyzed for their prediction accuracy of preterm delivery in order to establish which uterine EMG recording location was optimal signal data. Overall, our results show a clear improvement in prediction accuracy of preterm delivery risk compared with previous approaches, achieving an impressive maximum AUC value of 0.986 when using signals from an electrode positioned below the navel. In sum, this provides a promising new method for analyzing uterine EMG signals to permit accurate clinical assessment of preterm delivery risk.

  10. Combination of Empirical Mode Decomposition Components of HRV Signals for Discriminating Emotional States

    Directory of Open Access Journals (Sweden)

    Ateke Goshvarpour

    2016-06-01

    Full Text Available Introduction Automatic human emotion recognition is one of the most interesting topics in the field of affective computing. However, development of a reliable approach with a reasonable recognition rate is a challenging task. The main objective of the present study was to propose a robust method for discrimination of emotional responses thorough examination of heart rate variability (HRV. In the present study, considering the non-stationary and non-linear characteristics of HRV, empirical mode decomposition technique was utilized as a feature extraction approach. Materials and Methods In order to induce the emotional states, images indicating four emotional states, i.e., happiness, peacefulness, sadness, and fearfulness were presented. Simultaneously, HRV was recorded in 47 college students. The signals were decomposed into some intrinsic mode functions (IMFs. For each IMF and different IMF combinations, 17 standard and non-linear parameters were extracted. Wilcoxon test was conducted to assess the difference between IMF parameters in different emotional states. Afterwards, a probabilistic neural network was used to classify the features into emotional classes. Results Based on the findings, maximum classification rates were achieved when all IMFs were fed into the classifier. Under such circumstances, the proposed algorithm could discriminate the affective states with sensitivity, specificity, and correct classification rate of 99.01%, 100%, and 99.09%, respectively. In contrast, the lowest discrimination rates were attained by IMF1 frequency and its combinations. Conclusion The high performance of the present approach indicated that the proposed method is applicable for automatic emotion recognition.

  11. Completed Ensemble Empirical Mode Decomposition: a Robust Signal Processing Tool to Identify Sequence Strata

    Science.gov (United States)

    Purba, H.; Musu, J. T.; Diria, S. A.; Permono, W.; Sadjati, O.; Sopandi, I.; Ruzi, F.

    2018-03-01

    Well logging data provide many geological information and its trends resemble nonlinear or non-stationary signals. As long well log data recorded, there will be external factors can interfere or influence its signal resolution. A sensitive signal analysis is required to improve the accuracy of logging interpretation which it becomes an important thing to determine sequence stratigraphy. Complete Ensemble Empirical Mode Decomposition (CEEMD) is one of nonlinear and non-stationary signal analysis method which decomposes complex signal into a series of intrinsic mode function (IMF). Gamma Ray and Spontaneous Potential well log parameters decomposed into IMF-1 up to IMF-10 and each of its combination and correlation makes physical meaning identification. It identifies the stratigraphy and cycle sequence and provides an effective signal treatment method for sequence interface. This method was applied to BRK- 30 and BRK-13 well logging data. The result shows that the combination of IMF-5, IMF-6, and IMF-7 pattern represent short-term and middle-term while IMF-9 and IMF-10 represent the long-term sedimentation which describe distal front and delta front facies, and inter-distributary mouth bar facies, respectively. Thus, CEEMD clearly can determine the different sedimentary layer interface and better identification of the cycle of stratigraphic base level.

  12. Denoising of chaotic signal using independent component analysis and empirical mode decomposition with circulate translating

    Science.gov (United States)

    Wen-Bo, Wang; Xiao-Dong, Zhang; Yuchan, Chang; Xiang-Li, Wang; Zhao, Wang; Xi, Chen; Lei, Zheng

    2016-01-01

    In this paper, a new method to reduce noises within chaotic signals based on ICA (independent component analysis) and EMD (empirical mode decomposition) is proposed. The basic idea is decomposing chaotic signals and constructing multidimensional input vectors, firstly, on the base of EMD and its translation invariance. Secondly, it makes the independent component analysis on the input vectors, which means that a self adapting denoising is carried out for the intrinsic mode functions (IMFs) of chaotic signals. Finally, all IMFs compose the new denoised chaotic signal. Experiments on the Lorenz chaotic signal composed of different Gaussian noises and the monthly observed chaotic sequence on sunspots were put into practice. The results proved that the method proposed in this paper is effective in denoising of chaotic signals. Moreover, it can correct the center point in the phase space effectively, which makes it approach the real track of the chaotic attractor. Project supported by the National Science and Technology, China (Grant No. 2012BAJ15B04), the National Natural Science Foundation of China (Grant Nos. 41071270 and 61473213), the Natural Science Foundation of Hubei Province, China (Grant No. 2015CFB424), the State Key Laboratory Foundation of Satellite Ocean Environment Dynamics, China (Grant No. SOED1405), the Hubei Provincial Key Laboratory Foundation of Metallurgical Industry Process System Science, China (Grant No. Z201303), and the Hubei Key Laboratory Foundation of Transportation Internet of Things, Wuhan University of Technology, China (Grant No.2015III015-B02).

  13. Prediction of mean monthly river discharges in Colombia through Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    A. M. Carmona

    2015-04-01

    Full Text Available The hydro-climatology of Colombia exhibits strong natural variability at a broad range of time scales including: inter-decadal, decadal, inter-annual, annual, intra-annual, intra-seasonal, and diurnal. Diverse applied sectors rely on quantitative predictions of river discharges for operational purposes including hydropower generation, agriculture, human health, fluvial navigation, territorial planning and management, risk preparedness and mitigation, among others. Various methodologies have been used to predict monthly mean river discharges that are based on "Predictive Analytics", an area of statistical analysis that studies the extraction of information from historical data to infer future trends and patterns. Our study couples the Empirical Mode Decomposition (EMD with traditional methods, e.g. Autoregressive Model of Order 1 (AR1 and Neural Networks (NN, to predict mean monthly river discharges in Colombia, South America. The EMD allows us to decompose the historical time series of river discharges into a finite number of intrinsic mode functions (IMF that capture the different oscillatory modes of different frequencies associated with the inherent time scales coexisting simultaneously in the signal (Huang et al. 1998, Huang and Wu 2008, Rao and Hsu, 2008. Our predictive method states that it is easier and simpler to predict each IMF at a time and then add them up together to obtain the predicted river discharge for a certain month, than predicting the full signal. This method is applied to 10 series of monthly mean river discharges in Colombia, using calibration periods of more than 25 years, and validation periods of about 12 years. Predictions are performed for time horizons spanning from 1 to 12 months. Our results show that predictions obtained through the traditional methods improve when the EMD is used as a previous step, since errors decrease by up to 13% when the AR1 model is used, and by up to 18% when using Neural Networks is

  14. Empirical Mode Decomposition of Geophysical Well-log Data of Bombay Offshore Basin, Mumbai, India

    Science.gov (United States)

    Siddharth Gairola, Gaurav; Chandrasekhar, Enamundram

    2016-04-01

    Geophysical well-log data manifest the nonlinear behaviour of their respective physical properties of the heterogeneous subsurface layers as a function of depth. Therefore, nonlinear data analysis techniques must be implemented, to quantify the degree of heterogeneity in the subsurface lithologies. One such nonlinear data adaptive technique is empirical mode decomposition (EMD) technique, which facilitates to decompose the data into oscillatory signals of different wavelengths called intrinsic mode functions (IMF). In the present study EMD has been applied to gamma-ray log and neutron porosity log of two different wells: Well B and Well C located in the western offshore basin of India to perform heterogeneity analysis and compare the results with those obtained by multifractal studies of the same data sets. By establishing a relationship between the IMF number (m) and the mean wavelength associated with each IMF (Im), a heterogeneity index (ρ) associated with subsurface layers can be determined using the relation, Im=kρm, where 'k' is a constant. The ρ values bear an inverse relation with the heterogeneity of the subsurface: smaller ρ values designate higher heterogeneity and vice-versa. The ρ values estimated for different limestone payzones identified in the wells clearly show that Well C has higher degree of heterogeneity than Well B. This correlates well with the estimated Vshale values for the limestone reservoir zone showing higher shale content in Well C than Well B. The ρ values determined for different payzones of both wells will be used to quantify the degree of heterogeneity in different wells. The multifractal behaviour of each IMF of both the logs of both the wells will be compared with one another and discussed on the lines of their heterogeneity indices.

  15. Ensemble Empirical Mode Decomposition based methodology for ultrasonic testing of coarse grain austenitic stainless steels.

    Science.gov (United States)

    Sharma, Govind K; Kumar, Anish; Jayakumar, T; Purnachandra Rao, B; Mariyappa, N

    2015-03-01

    A signal processing methodology is proposed in this paper for effective reconstruction of ultrasonic signals in coarse grained high scattering austenitic stainless steel. The proposed methodology is comprised of the Ensemble Empirical Mode Decomposition (EEMD) processing of ultrasonic signals and application of signal minimisation algorithm on selected Intrinsic Mode Functions (IMFs) obtained by EEMD. The methodology is applied to ultrasonic signals obtained from austenitic stainless steel specimens of different grain size, with and without defects. The influence of probe frequency and data length of a signal on EEMD decomposition is also investigated. For a particular sampling rate and probe frequency, the same range of IMFs can be used to reconstruct the ultrasonic signal, irrespective of the grain size in the range of 30-210 μm investigated in this study. This methodology is successfully employed for detection of defects in a 50mm thick coarse grain austenitic stainless steel specimens. Signal to noise ratio improvement of better than 15 dB is observed for the ultrasonic signal obtained from a 25 mm deep flat bottom hole in 200 μm grain size specimen. For ultrasonic signals obtained from defects at different depths, a minimum of 7 dB extra enhancement in SNR is achieved as compared to the sum of selected IMF approach. The application of minimisation algorithm with EEMD processed signal in the proposed methodology proves to be effective for adaptive signal reconstruction with improved signal to noise ratio. This methodology was further employed for successful imaging of defects in a B-scan. Copyright © 2014. Published by Elsevier B.V.

  16. Temporal associations between weather and headache: analysis by empirical mode decomposition.

    Directory of Open Access Journals (Sweden)

    Albert C Yang

    Full Text Available BACKGROUND: Patients frequently report that weather changes trigger headache or worsen existing headache symptoms. Recently, the method of empirical mode decomposition (EMD has been used to delineate temporal relationships in certain diseases, and we applied this technique to identify intrinsic weather components associated with headache incidence data derived from a large-scale epidemiological survey of headache in the Greater Taipei area. METHODOLOGY/PRINCIPAL FINDINGS: The study sample consisted of 52 randomly selected headache patients. The weather time-series parameters were detrended by the EMD method into a set of embedded oscillatory components, i.e. intrinsic mode functions (IMFs. Multiple linear regression models with forward stepwise methods were used to analyze the temporal associations between weather and headaches. We found no associations between the raw time series of weather variables and headache incidence. For decomposed intrinsic weather IMFs, temperature, sunshine duration, humidity, pressure, and maximal wind speed were associated with headache incidence during the cold period, whereas only maximal wind speed was associated during the warm period. In analyses examining all significant weather variables, IMFs derived from temperature and sunshine duration data accounted for up to 33.3% of the variance in headache incidence during the cold period. The association of headache incidence and weather IMFs in the cold period coincided with the cold fronts. CONCLUSIONS/SIGNIFICANCE: Using EMD analysis, we found a significant association between headache and intrinsic weather components, which was not detected by direct comparisons of raw weather data. Contributing weather parameters may vary in different geographic regions and different seasons.

  17. A novel signal compression method based on optimal ensemble empirical mode decomposition for bearing vibration signals

    Science.gov (United States)

    Guo, Wei; Tse, Peter W.

    2013-01-01

    Today, remote machine condition monitoring is popular due to the continuous advancement in wireless communication. Bearing is the most frequently and easily failed component in many rotating machines. To accurately identify the type of bearing fault, large amounts of vibration data need to be collected. However, the volume of transmitted data cannot be too high because the bandwidth of wireless communication is limited. To solve this problem, the data are usually compressed before transmitting to a remote maintenance center. This paper proposes a novel signal compression method that can substantially reduce the amount of data that need to be transmitted without sacrificing the accuracy of fault identification. The proposed signal compression method is based on ensemble empirical mode decomposition (EEMD), which is an effective method for adaptively decomposing the vibration signal into different bands of signal components, termed intrinsic mode functions (IMFs). An optimization method was designed to automatically select appropriate EEMD parameters for the analyzed signal, and in particular to select the appropriate level of the added white noise in the EEMD method. An index termed the relative root-mean-square error was used to evaluate the decomposition performances under different noise levels to find the optimal level. After applying the optimal EEMD method to a vibration signal, the IMF relating to the bearing fault can be extracted from the original vibration signal. Compressing this signal component obtains a much smaller proportion of data samples to be retained for transmission and further reconstruction. The proposed compression method were also compared with the popular wavelet compression method. Experimental results demonstrate that the optimization of EEMD parameters can automatically find appropriate EEMD parameters for the analyzed signals, and the IMF-based compression method provides a higher compression ratio, while retaining the bearing defect

  18. Solving theoretical and empirical conundrums in international strategy research by matching foreign entry mode choices and performance

    NARCIS (Netherlands)

    Martin, Xavier

    2013-01-01

    Several theoretical and empirical developments in the literature on foreign entry mode and performance, and on (international) strategy more generally, were influenced or prefigured by Brouthers’ (2002) JIBS Decade Award winning paper. Regarding theory, Brouthers is an archetype of the integration

  19. Dansyl labeling and bidimensional mass spectrometry to investigate protein carbonylation.

    Science.gov (United States)

    Palmese, Angelo; De Rosa, Chiara; Marino, Gennaro; Amoresano, Angela

    2011-01-15

    Carbonylation is a non-enzymatic irreversible post-translational modification. The adduction of carbonyl groups to proteins is due to the presence of excess of ROS in cells. Carbonylation of specific amino acid side chains is one of the most abundant consequences of oxidative stress; therefore, the determination of carbonyl groups content in proteins is regarded as a reliable way to estimate the cellular damage caused by oxidative stress. This paper reports a novel RIGhT (Reporter Ion Generating Tag) (A. Amoresano, G. Monti, C. Cirulli, G. Marino. Rapid Commun. Mass Spectrom. 2006, 20, 1400) approach for selective labeling of carbonyl groups in proteins using dansylhydrazide, coupled with selective analysis by bidimensional mass spectrometry. We first applied this approach to ribonuclease A and lysozyme as model proteins. According to the so-called 'gel-free procedures', the analysis is carried out at the level of peptides following tryptic digest of the whole protein mixture. Modified RNaseA was analyzed in combined MS(2) and MS(3) scan mode, to specifically select the dansylated species taking advantage of the dansyl-specific fragmentation pathways. This combination allowed us to obtain a significant increase in signal/noise ratio and a significant increase in sensitivity of analysis, due to the reduction of duty cycle of the mass spectrometer. The unique signal obtained was correlated to peptide 1-10 of RNaseA carbonylated and labeled by dansylhydrazide. This strategy represents the first method leading to the direct identification of the carbonylation sites in proteins, thus indicating the feasibility of this strategy to investigate protein carbonylation in a proteomic approach. Copyright © 2010 John Wiley & Sons, Ltd.

  20. Rabi oscillations in bidimensional photonic crystals

    International Nuclear Information System (INIS)

    Centeno, E.; Felbacq, D.

    2000-01-01

    We theoretically and numerically investigate transient phenomena in finite two-dimensional photonic crystals doped by single-mode microcavities. We show that for antisymmetric defect modes, there are Rabi oscillations between the microcavities. We develop a spectral analysis which permits us to compute the Rabi frequencies of these oscillations as well as the Q factor of the microcavities. We present a method allowing the computation of the coupling factor between localized modes

  1. Bivariate empirical mode decomposition for ECG-based biometric identification with emotional data.

    Science.gov (United States)

    Ferdinando, Hany; Seppanen, Tapio; Alasaarela, Esko

    2017-07-01

    Emotions modulate ECG signals such that they might affect ECG-based biometric identification in real life application. It motivated in finding good feature extraction methods where the emotional state of the subjects has minimum impacts. This paper evaluates feature extraction based on bivariate empirical mode decomposition (BEMD) for biometric identification when emotion is considered. Using the ECG signal from the Mahnob-HCI database for affect recognition, the features were statistical distributions of dominant frequency after applying BEMD analysis to ECG signals. The achieved accuracy was 99.5% with high consistency using kNN classifier in 10-fold cross validation to identify 26 subjects when the emotional states of the subjects were ignored. When the emotional states of the subject were considered, the proposed method also delivered high accuracy, around 99.4%. We concluded that the proposed method offers emotion-independent features for ECG-based biometric identification. The proposed method needs more evaluation related to testing with other classifier and variation in ECG signals, e.g. normal ECG vs. ECG with arrhythmias, ECG from various ages, and ECG from other affective databases.

  2. The application of empirical mode decomposition for the enhancement of cardiotocograph signals

    International Nuclear Information System (INIS)

    Krupa, B N; Mohd Ali, M A; Zahedi, E

    2009-01-01

    Cardiotocograph (CTG) is widely used in everyday clinical practice for fetal surveillance, where it is used to record fetal heart rate (FHR) and uterine activity (UA). These two biosignals can be used for antepartum and intrapartum fetal monitoring and are, in fact, nonlinear and non-stationary. CTG recordings are often corrupted by artifacts such as missing beats in FHR, high-frequency noise in FHR and UA signals. In this paper, an empirical mode decomposition (EMD) method is applied on CTG signals. A recursive algorithm is first utilized to eliminate missing beats. High-frequency noise is reduced using EMD followed by the partial reconstruction (PAR) method, where the noise order is identified by a statistical method. The obtained signal enhancement from the proposed method is validated by comparing the resulting traces with the output obtained by applying classical signal processing methods such as Butterworth low-pass filtering, linear interpolation and a moving average filter on 12 CTG signals. Three obstetricians evaluated all 12 sets of traces and rated the proposed method, on average, 3.8 out of 5 on a scale of 1(lowest) to 5 (highest)

  3. Fluorescence Intrinsic Characterization of Excitation-Emission Matrix Using Multi-Dimensional Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Tzu-Chien Hsiao

    2013-11-01

    Full Text Available Excitation-emission matrix (EEM fluorescence spectroscopy is a noninvasive method for tissue diagnosis and has become important in clinical use. However, the intrinsic characterization of EEM fluorescence remains unclear. Photobleaching and the complexity of the chemical compounds make it difficult to distinguish individual compounds due to overlapping features. Conventional studies use principal component analysis (PCA for EEM fluorescence analysis, and the relationship between the EEM features extracted by PCA and diseases has been examined. The spectral features of different tissue constituents are not fully separable or clearly defined. Recently, a non-stationary method called multi-dimensional ensemble empirical mode decomposition (MEEMD was introduced; this method can extract the intrinsic oscillations on multiple spatial scales without loss of information. The aim of this study was to propose a fluorescence spectroscopy system for EEM measurements and to describe a method for extracting the intrinsic characteristics of EEM by MEEMD. The results indicate that, although PCA provides the principal factor for the spectral features associated with chemical compounds, MEEMD can provide additional intrinsic features with more reliable mapping of the chemical compounds. MEEMD has the potential to extract intrinsic fluorescence features and improve the detection of biochemical changes.

  4. Empirical Mode Decomposition and Neural Networks on FPGA for Fault Diagnosis in Induction Motors

    Directory of Open Access Journals (Sweden)

    David Camarena-Martinez

    2014-01-01

    Full Text Available Nowadays, many industrial applications require online systems that combine several processing techniques in order to offer solutions to complex problems as the case of detection and classification of multiple faults in induction motors. In this work, a novel digital structure to implement the empirical mode decomposition (EMD for processing nonstationary and nonlinear signals using the full spline-cubic function is presented; besides, it is combined with an adaptive linear network (ADALINE-based frequency estimator and a feed forward neural network (FFNN-based classifier to provide an intelligent methodology for the automatic diagnosis during the startup transient of motor faults such as: one and two broken rotor bars, bearing defects, and unbalance. Moreover, the overall methodology implementation into a field-programmable gate array (FPGA allows an online and real-time operation, thanks to its parallelism and high-performance capabilities as a system-on-a-chip (SoC solution. The detection and classification results show the effectiveness of the proposed fused techniques; besides, the high precision and minimum resource usage of the developed digital structures make them a suitable and low-cost solution for this and many other industrial applications.

  5. Investigating properties of the cardiovascular system using innovative analysis algorithms based on ensemble empirical mode decomposition.

    Science.gov (United States)

    Yeh, Jia-Rong; Lin, Tzu-Yu; Chen, Yun; Sun, Wei-Zen; Abbod, Maysam F; Shieh, Jiann-Shing

    2012-01-01

    Cardiovascular system is known to be nonlinear and nonstationary. Traditional linear assessments algorithms of arterial stiffness and systemic resistance of cardiac system accompany the problem of nonstationary or inconvenience in practical applications. In this pilot study, two new assessment methods were developed: the first is ensemble empirical mode decomposition based reflection index (EEMD-RI) while the second is based on the phase shift between ECG and BP on cardiac oscillation. Both methods utilise the EEMD algorithm which is suitable for nonlinear and nonstationary systems. These methods were used to investigate the properties of arterial stiffness and systemic resistance for a pig's cardiovascular system via ECG and blood pressure (BP). This experiment simulated a sequence of continuous changes of blood pressure arising from steady condition to high blood pressure by clamping the artery and an inverse by relaxing the artery. As a hypothesis, the arterial stiffness and systemic resistance should vary with the blood pressure due to clamping and relaxing the artery. The results show statistically significant correlations between BP, EEMD-based RI, and the phase shift between ECG and BP on cardiac oscillation. The two assessments results demonstrate the merits of the EEMD for signal analysis.

  6. Electrocardiogram signal denoising based on empirical mode decomposition technique: an overview

    International Nuclear Information System (INIS)

    Han, G.; Lin, B.; Xu, Z.

    2017-01-01

    Electrocardiogram (ECG) signal is nonlinear and non-stationary weak signal which reflects whether the heart is functioning normally or abnormally. ECG signal is susceptible to various kinds of noises such as high/low frequency noises, powerline interference and baseline wander. Hence, the removal of noises from ECG signal becomes a vital link in the ECG signal processing and plays a significant role in the detection and diagnosis of heart diseases. The review will describe the recent developments of ECG signal denoising based on Empirical Mode Decomposition (EMD) technique including high frequency noise removal, powerline interference separation, baseline wander correction, the combining of EMD and Other Methods, EEMD technique. EMD technique is a quite potential and prospective but not perfect method in the application of processing nonlinear and non-stationary signal like ECG signal. The EMD combined with other algorithms is a good solution to improve the performance of noise cancellation. The pros and cons of EMD technique in ECG signal denoising are discussed in detail. Finally, the future work and challenges in ECG signal denoising based on EMD technique are clarified.

  7. Electrocardiogram signal denoising based on empirical mode decomposition technique: an overview

    Science.gov (United States)

    Han, G.; Lin, B.; Xu, Z.

    2017-03-01

    Electrocardiogram (ECG) signal is nonlinear and non-stationary weak signal which reflects whether the heart is functioning normally or abnormally. ECG signal is susceptible to various kinds of noises such as high/low frequency noises, powerline interference and baseline wander. Hence, the removal of noises from ECG signal becomes a vital link in the ECG signal processing and plays a significant role in the detection and diagnosis of heart diseases. The review will describe the recent developments of ECG signal denoising based on Empirical Mode Decomposition (EMD) technique including high frequency noise removal, powerline interference separation, baseline wander correction, the combining of EMD and Other Methods, EEMD technique. EMD technique is a quite potential and prospective but not perfect method in the application of processing nonlinear and non-stationary signal like ECG signal. The EMD combined with other algorithms is a good solution to improve the performance of noise cancellation. The pros and cons of EMD technique in ECG signal denoising are discussed in detail. Finally, the future work and challenges in ECG signal denoising based on EMD technique are clarified.

  8. New GRACE-Derived Storage Change Estimates Using Empirical Mode Extraction

    Science.gov (United States)

    Aierken, A.; Lee, H.; Yu, H.; Ate, P.; Hossain, F.; Basnayake, S. B.; Jayasinghe, S.; Saah, D. S.; Shum, C. K.

    2017-12-01

    Estimated mass change from GRACE spherical harmonic solutions have north/south stripes and east/west banded errors due to random noise and modeling errors. Low pass filters like decorrelation and Gaussian smoothing are typically applied to reduce noise and errors. However, these filters introduce leakage errors that need to be addressed. GRACE mascon estimates (JPL and CSR mascon solutions) do not need decorrelation or Gaussian smoothing and offer larger signal magnitudes compared to the GRACE spherical harmonics (SH) filtered results. However, a recent study [Chen et al., JGR, 2017] demonstrated that both JPL and CSR mascon solutions also have leakage errors. We developed a new postprocessing method based on empirical mode decomposition to estimate mass change from GRACE SH solutions without decorrelation and Gaussian smoothing, the two main sources of leakage errors. We found that, without any post processing, the noise and errors in spherical harmonic solutions introduced very clear high frequency components in the spatial domain. By removing these high frequency components and reserve the overall pattern of the signal, we obtained better mass estimates with minimum leakage errors. The new global mass change estimates captured all the signals observed by GRACE without the stripe errors. Results were compared with traditional methods over the Tonle Sap Basin in Cambodia, Northwestern India, Central Valley in California, and the Caspian Sea. Our results provide larger signal magnitudes which are in good agreement with the leakage corrected (forward modeled) SH results.

  9. Photoacoustic imaging optimization with raw signal deconvolution and empirical mode decomposition

    Science.gov (United States)

    Guo, Chengwen; Wang, Jing; Qin, Yu; Zhan, Hongchen; Yuan, Jie; Cheng, Qian; Wang, Xueding

    2018-02-01

    Photoacoustic (PA) signal of an ideal optical absorb particle is a single N-shape wave. PA signals of a complicated biological tissue can be considered as the combination of individual N-shape waves. However, the N-shape wave basis not only complicates the subsequent work, but also results in aliasing between adjacent micro-structures, which deteriorates the quality of the final PA images. In this paper, we propose a method to improve PA image quality through signal processing method directly working on raw signals, which including deconvolution and empirical mode decomposition (EMD). During the deconvolution procedure, the raw PA signals are de-convolved with a system dependent point spread function (PSF) which is measured in advance. Then, EMD is adopted to adaptively re-shape the PA signals with two constraints, positive polarity and spectrum consistence. With our proposed method, the built PA images can yield more detail structural information. Micro-structures are clearly separated and revealed. To validate the effectiveness of this method, we present numerical simulations and phantom studies consist of a densely distributed point sources model and a blood vessel model. In the future, our study might hold the potential for clinical PA imaging as it can help to distinguish micro-structures from the optimized images and even measure the size of objects from deconvolved signals.

  10. Exercise muscle fatigue detection system implementation via wireless surface electromyography and empirical mode decomposition.

    Science.gov (United States)

    Chang, Kang-Ming; Liu, Shing-Hong; Wang, Jia-Jung; Cheng, Da-Chuan

    2013-01-01

    Surface electromyography (sEMG) is an important measurement for monitoring exercise and fitness. A wireless Bluetooth transmission sEMG measurement system with a sampling frequency of 2 KHz is developed. Traditional muscle fatigue is detected from the median frequency of the sEMG power spectrum. The regression slope of the linear regression of median frequency is an important muscle fatigue index. As fatigue increases, the power spectrum of the sEMG shifts toward lower frequencies. The goal of this study is to evaluate the sensitivity of empirical mode decomposition (EMD) quantifying the electrical manifestations of the local muscle fatigue during exercising in health people. We also compared this method with the raw data and discrete wavelet transform (DWT). Five male and five female volunteers participated. Each subject was asked to run on a multifunctional pedaled elliptical trainer for about 30 minutes, twice a week, and there were a total of six recording times for each subject with a wireless EMG recording system. The results show that sensitivity of the highest frequency component of EMD is better than the highest frequency component of DWT, and raw data.

  11. Empirical Mode Decomposition and Neural Networks on FPGA for Fault Diagnosis in Induction Motors

    Science.gov (United States)

    Garcia-Perez, Arturo; Osornio-Rios, Roque Alfredo; Romero-Troncoso, Rene de Jesus

    2014-01-01

    Nowadays, many industrial applications require online systems that combine several processing techniques in order to offer solutions to complex problems as the case of detection and classification of multiple faults in induction motors. In this work, a novel digital structure to implement the empirical mode decomposition (EMD) for processing nonstationary and nonlinear signals using the full spline-cubic function is presented; besides, it is combined with an adaptive linear network (ADALINE)-based frequency estimator and a feed forward neural network (FFNN)-based classifier to provide an intelligent methodology for the automatic diagnosis during the startup transient of motor faults such as: one and two broken rotor bars, bearing defects, and unbalance. Moreover, the overall methodology implementation into a field-programmable gate array (FPGA) allows an online and real-time operation, thanks to its parallelism and high-performance capabilities as a system-on-a-chip (SoC) solution. The detection and classification results show the effectiveness of the proposed fused techniques; besides, the high precision and minimum resource usage of the developed digital structures make them a suitable and low-cost solution for this and many other industrial applications. PMID:24678281

  12. Partial differential equation-based approach for empirical mode decomposition: application on image analysis.

    Science.gov (United States)

    Niang, Oumar; Thioune, Abdoulaye; El Gueirea, Mouhamed Cheikh; Deléchelle, Eric; Lemoine, Jacques

    2012-09-01

    The major problem with the empirical mode decomposition (EMD) algorithm is its lack of a theoretical framework. So, it is difficult to characterize and evaluate this approach. In this paper, we propose, in the 2-D case, the use of an alternative implementation to the algorithmic definition of the so-called "sifting process" used in the original Huang's EMD method. This approach, especially based on partial differential equations (PDEs), was presented by Niang in previous works, in 2005 and 2007, and relies on a nonlinear diffusion-based filtering process to solve the mean envelope estimation problem. In the 1-D case, the efficiency of the PDE-based method, compared to the original EMD algorithmic version, was also illustrated in a recent paper. Recently, several 2-D extensions of the EMD method have been proposed. Despite some effort, 2-D versions for EMD appear poorly performing and are very time consuming. So in this paper, an extension to the 2-D space of the PDE-based approach is extensively described. This approach has been applied in cases of both signal and image decomposition. The obtained results confirm the usefulness of the new PDE-based sifting process for the decomposition of various kinds of data. Some results have been provided in the case of image decomposition. The effectiveness of the approach encourages its use in a number of signal and image applications such as denoising, detrending, or texture analysis.

  13. Empirical Mode Decomposition on the sphere: application to the spatial scales of surface temperature variations

    Directory of Open Access Journals (Sweden)

    N. Fauchereau

    2008-06-01

    Full Text Available Empirical Mode Decomposition (EMD is applied here in two dimensions over the sphere to demonstrate its potential as a data-adaptive method of separating the different scales of spatial variability in a geophysical (climatological/meteorological field. After a brief description of the basics of the EMD in 1 then 2 dimensions, the principles of its application on the sphere are explained, in particular via the use of a zonal equal area partitioning. EMD is first applied to an artificial dataset, demonstrating its capability in extracting the different (known scales embedded in the field. The decomposition is then applied to a global mean surface temperature dataset, and we show qualitatively that it extracts successively larger scales of temperature variations related, for example, to topographic and large-scale, solar radiation forcing. We propose that EMD can be used as a global data-adaptive filter, which will be useful in analysing geophysical phenomena that arise as the result of forcings at multiple spatial scales.

  14. Combination of canonical correlation analysis and empirical mode decomposition applied to denoising the labor electrohysterogram.

    Science.gov (United States)

    Hassan, Mahmoud; Boudaoud, Sofiane; Terrien, Jérémy; Karlsson, Brynjar; Marque, Catherine

    2011-09-01

    The electrohysterogram (EHG) is often corrupted by electronic and electromagnetic noise as well as movement artifacts, skeletal electromyogram, and ECGs from both mother and fetus. The interfering signals are sporadic and/or have spectra overlapping the spectra of the signals of interest rendering classical filtering ineffective. In the absence of efficient methods for denoising the monopolar EHG signal, bipolar methods are usually used. In this paper, we propose a novel combination of blind source separation using canonical correlation analysis (BSS_CCA) and empirical mode decomposition (EMD) methods to denoise monopolar EHG. We first extract the uterine bursts by using BSS_CCA then the biggest part of any residual noise is removed from the bursts by EMD. Our algorithm, called CCA_EMD, was compared with wavelet filtering and independent component analysis. We also compared CCA_EMD with the corresponding bipolar signals to demonstrate that the new method gives signals that have not been degraded by the new method. The proposed method successfully removed artifacts from the signal without altering the underlying uterine activity as observed by bipolar methods. The CCA_EMD algorithm performed considerably better than the comparison methods.

  15. Identifying the oil price-macroeconomy relationship. An empirical mode decomposition analysis of US data

    International Nuclear Information System (INIS)

    Oladosu, Gbadebo

    2009-01-01

    This paper employs the empirical mode decomposition (EMD) method to filter cyclical components of US quarterly gross domestic product (GDP) and quarterly average oil price (West Texas Intermediate - WTI). The method is adaptive and applicable to non-linear and non-stationary data. A correlation analysis of the resulting components is performed and examined for insights into the relationship between oil and the economy. Several components of this relationship are identified. However, the principal one is that the medium-run component of the oil price has a negative relationship with the main cyclical component of the GDP. In addition, weak correlations suggesting a lagging, demand-driven component and a long-run component of the relationship were also identified. Comparisons of these findings with significant oil supply disruption and recession dates were supportive. The study identifies a number of lessons applicable to recent oil market events, including the eventuality of persistent oil price and economic decline following a long oil price run-up. In addition, it was found that oil market related exogenous events are associated with short- to medium-run price implications regardless of whether they lead to actual supply losses. (author)

  16. Automated diagnosis of focal liver lesions using bidirectional empirical mode decomposition features.

    Science.gov (United States)

    Acharya, U Rajendra; Koh, Joel En Wei; Hagiwara, Yuki; Tan, Jen Hong; Gertych, Arkadiusz; Vijayananthan, Anushya; Yaakup, Nur Adura; Abdullah, Basri Johan Jeet; Bin Mohd Fabell, Mohd Kamil; Yeong, Chai Hong

    2018-03-01

    Liver is the heaviest internal organ of the human body and performs many vital functions. Prolonged cirrhosis and fatty liver disease may lead to the formation of benign or malignant lesions in this organ, and an early and reliable evaluation of these conditions can improve treatment outcomes. Ultrasound imaging is a safe, non-invasive, and cost-effective way of diagnosing liver lesions. However, this technique has limited performance in determining the nature of the lesions. This study initiates a computer-aided diagnosis (CAD) system to aid radiologists in an objective and more reliable interpretation of ultrasound images of liver lesions. In this work, we have employed radon transform and bi-directional empirical mode decomposition (BEMD) to extract features from the focal liver lesions. After which, the extracted features were subjected to particle swarm optimization (PSO) technique for the selection of a set of optimized features for classification. Our automated CAD system can differentiate normal, malignant, and benign liver lesions using machine learning algorithms. It was trained using 78 normal, 26 benign and 36 malignant focal lesions of the liver. The accuracy, sensitivity, and specificity of lesion classification were 92.95%, 90.80%, and 97.44%, respectively. The proposed CAD system is fully automatic as no segmentation of region-of-interest (ROI) is required. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Multivariate Empirical Mode Decomposition Based Signal Analysis and Efficient-Storage in Smart Grid

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lu [University of Tennessee, Knoxville (UTK); Albright, Austin P [ORNL; Rahimpour, Alireza [University of Tennessee, Knoxville (UTK); Guo, Jiandong [University of Tennessee, Knoxville (UTK); Qi, Hairong [University of Tennessee, Knoxville (UTK); Liu, Yilu [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)

    2017-01-01

    Wide-area-measurement systems (WAMSs) are used in smart grid systems to enable the efficient monitoring of grid dynamics. However, the overwhelming amount of data and the severe contamination from noise often impede the effective and efficient data analysis and storage of WAMS generated measurements. To solve this problem, we propose a novel framework that takes advantage of Multivariate Empirical Mode Decomposition (MEMD), a fully data-driven approach to analyzing non-stationary signals, dubbed MEMD based Signal Analysis (MSA). The frequency measurements are considered as a linear superposition of different oscillatory components and noise. The low-frequency components, corresponding to the long-term trend and inter-area oscillations, are grouped and compressed by MSA using the mean shift clustering algorithm. Whereas, higher-frequency components, mostly noise and potentially part of high-frequency inter-area oscillations, are analyzed using Hilbert spectral analysis and they are delineated by statistical behavior. By conducting experiments on both synthetic and real-world data, we show that the proposed framework can capture the characteristics, such as trends and inter-area oscillation, while reducing the data storage requirements

  18. Travel Mode Use, Travel Mode Shift and Subjective Well-Being: Overview of Theories, Empirical Findings and Policy Implications

    NARCIS (Netherlands)

    Ettema, D.F.; Friman, M.; Gärling, Tommy; Olsson, Lars

    2016-01-01

    This chapter discusses how travel by different travel modes is related to primarily subjective well-being but also to health or physical well-being. Studies carried out in different geographic contexts consistently show that satisfaction with active travel modes is higher than travel by car and

  19. Benchmarking of a T-wave alternans detection method based on empirical mode decomposition.

    Science.gov (United States)

    Blanco-Velasco, Manuel; Goya-Esteban, Rebeca; Cruz-Roldán, Fernando; García-Alberola, Arcadi; Rojo-Álvarez, José Luis

    2017-07-01

    T-wave alternans (TWA) is a fluctuation of the ST-T complex occurring on an every-other-beat basis of the surface electrocardiogram (ECG). It has been shown to be an informative risk stratifier for sudden cardiac death, though the lack of gold standard to benchmark detection methods has promoted the use of synthetic signals. This work proposes a novel signal model to study the performance of a TWA detection. Additionally, the methodological validation of a denoising technique based on empirical mode decomposition (EMD), which is used here along with the spectral method, is also tackled. The proposed test bed system is based on the following guidelines: (1) use of open source databases to enable experimental replication; (2) use of real ECG signals and physiological noise; (3) inclusion of randomized TWA episodes. Both sensitivity (Se) and specificity (Sp) are separately analyzed. Also a nonparametric hypothesis test, based on Bootstrap resampling, is used to determine whether the presence of the EMD block actually improves the performance. The results show an outstanding specificity when the EMD block is used, even in very noisy conditions (0.96 compared to 0.72 for SNR = 8 dB), being always superior than that of the conventional SM alone. Regarding the sensitivity, using the EMD method also outperforms in noisy conditions (0.57 compared to 0.46 for SNR=8 dB), while it decreases in noiseless conditions. The proposed test setting designed to analyze the performance guarantees that the actual physiological variability of the cardiac system is reproduced. The use of the EMD-based block in noisy environment enables the identification of most patients with fatal arrhythmias. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Investigating complex patterns of blocked intestinal artery blood pressure signals by empirical mode decomposition and linguistic analysis

    International Nuclear Information System (INIS)

    Yeh, J-R; Lin, T-Y; Shieh, J-S; Chen, Y; Huang, N E; Wu, Z; Peng, C-K

    2008-01-01

    In this investigation, surgical operations of blocked intestinal artery have been conducted on pigs to simulate the condition of acute mesenteric arterial occlusion. The empirical mode decomposition method and the algorithm of linguistic analysis were applied to verify the blood pressure signals in simulated situation. We assumed that there was some information hidden in the high-frequency part of the blood pressure signal when an intestinal artery is blocked. The empirical mode decomposition method (EMD) has been applied to decompose the intrinsic mode functions (IMF) from a complex time series. But, the end effects and phenomenon of intermittence damage the consistence of each IMF. Thus, we proposed the complementary ensemble empirical mode decomposition method (CEEMD) to solve the problems of end effects and the phenomenon of intermittence. The main wave of blood pressure signals can be reconstructed by the main components, identified by Monte Carlo verification, and removed from the original signal to derive a riding wave. Furthermore, the concept of linguistic analysis was applied to design the blocking index to verify the pattern of riding wave of blood pressure using the measurements of dissimilarity. Blocking index works well to identify the situation in which the sampled time series of blood pressure signal was recorded. Here, these two totally different algorithms are successfully integrated and the existence of the existence of information hidden in high-frequency part of blood pressure signal has been proven

  1. Investigating complex patterns of blocked intestinal artery blood pressure signals by empirical mode decomposition and linguistic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, J-R; Lin, T-Y; Shieh, J-S [Department of Mechanical Engineering, Yuan Ze University, 135 Far-East Road, Chung-Li, Taoyuan, Taiwan (China); Chen, Y [Far Eastern Memorial Hospital, Taiwan (China); Huang, N E [Research Center for Adaptive Data Analysis, National Central University, Taiwan (China); Wu, Z [Center for Ocean-Land-Atmosphere Studies (United States); Peng, C-K [Beth Israel Deaconess Medical Center, Harvard Medical School (United States)], E-mail: s939205@ mail.yzu.edu.tw

    2008-02-15

    In this investigation, surgical operations of blocked intestinal artery have been conducted on pigs to simulate the condition of acute mesenteric arterial occlusion. The empirical mode decomposition method and the algorithm of linguistic analysis were applied to verify the blood pressure signals in simulated situation. We assumed that there was some information hidden in the high-frequency part of the blood pressure signal when an intestinal artery is blocked. The empirical mode decomposition method (EMD) has been applied to decompose the intrinsic mode functions (IMF) from a complex time series. But, the end effects and phenomenon of intermittence damage the consistence of each IMF. Thus, we proposed the complementary ensemble empirical mode decomposition method (CEEMD) to solve the problems of end effects and the phenomenon of intermittence. The main wave of blood pressure signals can be reconstructed by the main components, identified by Monte Carlo verification, and removed from the original signal to derive a riding wave. Furthermore, the concept of linguistic analysis was applied to design the blocking index to verify the pattern of riding wave of blood pressure using the measurements of dissimilarity. Blocking index works well to identify the situation in which the sampled time series of blood pressure signal was recorded. Here, these two totally different algorithms are successfully integrated and the existence of the existence of information hidden in high-frequency part of blood pressure signal has been proven.

  2. Forecasting outpatient visits using empirical mode decomposition coupled with back-propagation artificial neural networks optimized by particle swarm optimization.

    Science.gov (United States)

    Huang, Daizheng; Wu, Zhihui

    2017-01-01

    Accurately predicting the trend of outpatient visits by mathematical modeling can help policy makers manage hospitals effectively, reasonably organize schedules for human resources and finances, and appropriately distribute hospital material resources. In this study, a hybrid method based on empirical mode decomposition and back-propagation artificial neural networks optimized by particle swarm optimization is developed to forecast outpatient visits on the basis of monthly numbers. The data outpatient visits are retrieved from January 2005 to December 2013 and first obtained as the original time series. Second, the original time series is decomposed into a finite and often small number of intrinsic mode functions by the empirical mode decomposition technique. Third, a three-layer back-propagation artificial neural network is constructed to forecast each intrinsic mode functions. To improve network performance and avoid falling into a local minimum, particle swarm optimization is employed to optimize the weights and thresholds of back-propagation artificial neural networks. Finally, the superposition of forecasting results of the intrinsic mode functions is regarded as the ultimate forecasting value. Simulation indicates that the proposed method attains a better performance index than the other four methods.

  3. Empirical mode decomposition and long-range correlation analysis of sunspot time series

    International Nuclear Information System (INIS)

    Zhou, Yu; Leung, Yee

    2010-01-01

    Sunspots, which are the best known and most variable features of the solar surface, affect our planet in many ways. The number of sunspots during a period of time is highly variable and arouses strong research interest. When multifractal detrended fluctuation analysis (MF-DFA) is employed to study the fractal properties and long-range correlation of the sunspot series, some spurious crossover points might appear because of the periodic and quasi-periodic trends in the series. However many cycles of solar activities can be reflected by the sunspot time series. The 11-year cycle is perhaps the most famous cycle of the sunspot activity. These cycles pose problems for the investigation of the scaling behavior of sunspot time series. Using different methods to handle the 11-year cycle generally creates totally different results. Using MF-DFA, Movahed and co-workers employed Fourier truncation to deal with the 11-year cycle and found that the series is long-range anti-correlated with a Hurst exponent, H, of about 0.12. However, Hu and co-workers proposed an adaptive detrending method for the MF-DFA and discovered long-range correlation characterized by H≈0.74. In an attempt to get to the bottom of the problem in the present paper, empirical mode decomposition (EMD), a data-driven adaptive method, is applied to first extract the components with different dominant frequencies. MF-DFA is then employed to study the long-range correlation of the sunspot time series under the influence of these components. On removing the effects of these periods, the natural long-range correlation of the sunspot time series can be revealed. With the removal of the 11-year cycle, a crossover point located at around 60 months is discovered to be a reasonable point separating two different time scale ranges, H≈0.72 and H≈1.49. And on removing all cycles longer than 11 years, we have H≈0.69 and H≈0.28. The three cycle-removing methods—Fourier truncation, adaptive detrending and the

  4. Identification of sudden stiffness changes in the acceleration response of a bridge to moving loads using ensemble empirical mode decomposition

    Science.gov (United States)

    Aied, H.; González, A.; Cantero, D.

    2016-01-01

    The growth of heavy traffic together with aggressive environmental loads poses a threat to the safety of an aging bridge stock. Often, damage is only detected via visual inspection at a point when repairing costs can be quite significant. Ideally, bridge managers would want to identify a stiffness change as soon as possible, i.e., as it is occurring, to plan for prompt measures before reaching a prohibitive cost. Recent developments in signal processing techniques such as wavelet analysis and empirical mode decomposition (EMD) have aimed to address this need by identifying a stiffness change from a localised feature in the structural response to traffic. However, the effectiveness of these techniques is limited by the roughness of the road profile, the vehicle speed and the noise level. In this paper, ensemble empirical mode decomposition (EEMD) is applied by the first time to the acceleration response of a bridge model to a moving load with the purpose of capturing sudden stiffness changes. EEMD is more adaptive and appears to be better suited to non-linear signals than wavelets, and it reduces the mode mixing problem present in EMD. EEMD is tested in a variety of theoretical 3D vehicle-bridge interaction scenarios. Stiffness changes are successfully identified, even for small affected regions, relatively poor profiles, high vehicle speeds and significant noise. The latter is due to the ability of EEMD to separate high frequency components associated to sudden stiffness changes from other frequency components associated to the vehicle-bridge interaction system.

  5. Explaining Student Interaction and Satisfaction: An Empirical Investigation of Delivery Mode Influence

    Science.gov (United States)

    Johnson, Zachary S.; Cascio, Robert; Massiah, Carolyn A.

    2014-01-01

    How interpersonal interactions within a course affect student satisfaction differently between face-to-face and online modes is an important research question to answer with confidence. Using students from a marketing course delivered face-to-face and online concurrently, our first study demonstrates that student-to-professor and…

  6. Relationship between mode choice and the location of supermarkets – empirical analysis in Austria

    Directory of Open Access Journals (Sweden)

    Roman KLEMENTSCHITZ

    2014-03-01

    Full Text Available Main goal of the study work is to gain data about shopping and mobility behaviour at small local supermarkets with sales floor space less than 1.000 m2. Four location types have been defined and discussed; rural  peripheral location, rural  central location, urban – central location and urban – peripheral location. 200 shoppers each location were interviewed at the exit of the supermarket, which means a total of 800 interviews were carried out during all day times and working days of the supermarket. As expected, the mode choice is strongly dependent on the location of the supermarket. In car oriented settlements, which can be found at rural peripheral locations, nearly all shoppers accessed the supermarket with their cars. If weighting the expenditure per visit with the frequency of visits, the average expenditure per month and mode can be derived. The average purchase per month between the modes is more or less balanced. A difference in behaviour lies in the fact that cyclists and pedestrians go shopping more frequently but are spending less per visit. Additionally, the results of this study are indicating the existence of a potential mode shift, especially if there is better land use planning for supermarket locations. Furthermore, considering the given situation and a given threshold of less than 5 kilograms of weight of the goods purchased, more than fifty percent of all shoppers could use non motorised modes with insignificant loss of travel quality. Combined with short travel distances to the next shop (the average distance is 4.9 km, a change to alternative means of transport would be relatively easy for a significant number of shoppers.

  7. Denoising traffic collision data using ensemble empirical mode decomposition (EEMD) and its application for constructing continuous risk profile (CRP).

    Science.gov (United States)

    Kim, Nam-Seog; Chung, Koohong; Ahn, Seongchae; Yu, Jeong Whon; Choi, Keechoo

    2014-10-01

    Filtering out the noise in traffic collision data is essential in reducing false positive rates (i.e., requiring safety investigation of sites where it is not needed) and can assist government agencies in better allocating limited resources. Previous studies have demonstrated that denoising traffic collision data is possible when there exists a true known high collision concentration location (HCCL) list to calibrate the parameters of a denoising method. However, such a list is often not readily available in practice. To this end, the present study introduces an innovative approach for denoising traffic collision data using the Ensemble Empirical Mode Decomposition (EEMD) method which is widely used for analyzing nonlinear and nonstationary data. The present study describes how to transform the traffic collision data before the data can be decomposed using the EEMD method to obtain set of Intrinsic Mode Functions (IMFs) and residue. The attributes of the IMFs were then carefully examined to denoise the data and to construct Continuous Risk Profiles (CRPs). The findings from comparing the resulting CRP profiles with CRPs in which the noise was filtered out with two different empirically calibrated weighted moving window lengths are also documented, and the results and recommendations for future research are discussed. Published by Elsevier Ltd.

  8. A Novel Multiscale Ensemble Carbon Price Prediction Model Integrating Empirical Mode Decomposition, Genetic Algorithm and Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Bangzhu Zhu

    2012-02-01

    Full Text Available Due to the movement and complexity of the carbon market, traditional monoscale forecasting approaches often fail to capture its nonstationary and nonlinear properties and accurately describe its moving tendencies. In this study, a multiscale ensemble forecasting model integrating empirical mode decomposition (EMD, genetic algorithm (GA and artificial neural network (ANN is proposed to forecast carbon price. Firstly, the proposed model uses EMD to decompose carbon price data into several intrinsic mode functions (IMFs and one residue. Then, the IMFs and residue are composed into a high frequency component, a low frequency component and a trend component which have similar frequency characteristics, simple components and strong regularity using the fine-to-coarse reconstruction algorithm. Finally, those three components are predicted using an ANN trained by GA, i.e., a GAANN model, and the final forecasting results can be obtained by the sum of these three forecasting results. For verification and testing, two main carbon future prices with different maturity in the European Climate Exchange (ECX are used to test the effectiveness of the proposed multiscale ensemble forecasting model. Empirical results obtained demonstrate that the proposed multiscale ensemble forecasting model can outperform the single random walk (RW, ARIMA, ANN and GAANN models without EMD preprocessing and the ensemble ARIMA model with EMD preprocessing.

  9. Modified sliding mechanics in extraction cases with a bidimensional approach.

    Science.gov (United States)

    Giancotti, Aldo; Greco, Mario

    2010-01-01

    To illustrate a modified archwire during space closure with anterior anchorage in Bidimensional Tecnique. The archwire used was a .018x.025 SS on the anterior teeth and .018 SS on the lateral and posterior teeth in order to maintain anterior anchorage using torque and uprighting springs as showed in Bidmensional Technique but exerting lighter forces (150 g). The double section archwire resulted to be an effective alternative option to optimize the lateral and posterior sliding mechanics with controlled tipping and by the application of lighter forces. Copyright © 2010 Società Italiana di Ortodonzia SIDO. Published by Elsevier Srl. All rights reserved.

  10. Gyroscope-driven mouse pointer with an EMOTIV® EEG headset and data analysis based on Empirical Mode Decomposition.

    Science.gov (United States)

    Rosas-Cholula, Gerardo; Ramirez-Cortes, Juan Manuel; Alarcon-Aquino, Vicente; Gomez-Gil, Pilar; Rangel-Magdaleno, Jose de Jesus; Reyes-Garcia, Carlos

    2013-08-14

    This paper presents a project on the development of a cursor control emulating the typical operations of a computer-mouse, using gyroscope and eye-blinking electromyographic signals which are obtained through a commercial 16-electrode wireless headset, recently released by Emotiv. The cursor position is controlled using information from a gyroscope included in the headset. The clicks are generated through the user's blinking with an adequate detection procedure based on the spectral-like technique called Empirical Mode Decomposition (EMD). EMD is proposed as a simple and quick computational tool, yet effective, aimed to artifact reduction from head movements as well as a method to detect blinking signals for mouse control. Kalman filter is used as state estimator for mouse position control and jitter removal. The detection rate obtained in average was 94.9%. Experimental setup and some obtained results are presented.

  11. Gyroscope-Driven Mouse Pointer with an EMOTIV® EEG Headset and Data Analysis Based on Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Carlos Reyes-Garcia

    2013-08-01

    Full Text Available This paper presents a project on the development of a cursor control emulating the typical operations of a computer-mouse, using gyroscope and eye-blinking electromyographic signals which are obtained through a commercial 16-electrode wireless headset, recently released by Emotiv. The cursor position is controlled using information from a gyroscope included in the headset. The clicks are generated through the user’s blinking with an adequate detection procedure based on the spectral-like technique called Empirical Mode Decomposition (EMD. EMD is proposed as a simple and quick computational tool, yet effective, aimed to artifact reduction from head movements as well as a method to detect blinking signals for mouse control. Kalman filter is used as state estimator for mouse position control and jitter removal. The detection rate obtained in average was 94.9%. Experimental setup and some obtained results are presented.

  12. Towards estimation of respiratory muscle effort with respiratory inductance plethysmography signals and complementary ensemble empirical mode decomposition.

    Science.gov (United States)

    Chen, Ya-Chen; Hsiao, Tzu-Chien

    2018-07-01

    Respiratory inductance plethysmography (RIP) sensor is an inexpensive, non-invasive, easy-to-use transducer for collecting respiratory movement data. Studies have reported that the RIP signal's amplitude and frequency can be used to discriminate respiratory diseases. However, with the conventional approach of RIP data analysis, respiratory muscle effort cannot be estimated. In this paper, the estimation of the respiratory muscle effort through RIP signal was proposed. A complementary ensemble empirical mode decomposition method was used, to extract hidden signals from the RIP signals based on the frequency bands of the activities of different respiratory muscles. To validate the proposed method, an experiment to collect subjects' RIP signal under thoracic breathing (TB) and abdominal breathing (AB) was conducted. The experimental results for both the TB and AB indicate that the proposed method can be used to loosely estimate the activities of thoracic muscles, abdominal muscles, and diaphragm. Graphical abstract ᅟ.

  13. A novel approach for baseline correction in 1H-MRS signals based on ensemble empirical mode decomposition.

    Science.gov (United States)

    Parto Dezfouli, Mohammad Ali; Dezfouli, Mohsen Parto; Rad, Hamidreza Saligheh

    2014-01-01

    Proton magnetic resonance spectroscopy ((1)H-MRS) is a non-invasive diagnostic tool for measuring biochemical changes in the human body. Acquired (1)H-MRS signals may be corrupted due to a wideband baseline signal generated by macromolecules. Recently, several methods have been developed for the correction of such baseline signals, however most of them are not able to estimate baseline in complex overlapped signal. In this study, a novel automatic baseline correction method is proposed for (1)H-MRS spectra based on ensemble empirical mode decomposition (EEMD). This investigation was applied on both the simulated data and the in-vivo (1)H-MRS of human brain signals. Results justify the efficiency of the proposed method to remove the baseline from (1)H-MRS signals.

  14. A new multivariate empirical mode decomposition method for improving the performance of SSVEP-based brain-computer interface

    Science.gov (United States)

    Chen, Yi-Feng; Atal, Kiran; Xie, Sheng-Quan; Liu, Quan

    2017-08-01

    Objective. Accurate and efficient detection of steady-state visual evoked potentials (SSVEP) in electroencephalogram (EEG) is essential for the related brain-computer interface (BCI) applications. Approach. Although the canonical correlation analysis (CCA) has been applied extensively and successfully to SSVEP recognition, the spontaneous EEG activities and artifacts that often occur during data recording can deteriorate the recognition performance. Therefore, it is meaningful to extract a few frequency sub-bands of interest to avoid or reduce the influence of unrelated brain activity and artifacts. This paper presents an improved method to detect the frequency component associated with SSVEP using multivariate empirical mode decomposition (MEMD) and CCA (MEMD-CCA). EEG signals from nine healthy volunteers were recorded to evaluate the performance of the proposed method for SSVEP recognition. Main results. We compared our method with CCA and temporally local multivariate synchronization index (TMSI). The results suggest that the MEMD-CCA achieved significantly higher accuracy in contrast to standard CCA and TMSI. It gave the improvements of 1.34%, 3.11%, 3.33%, 10.45%, 15.78%, 18.45%, 15.00% and 14.22% on average over CCA at time windows from 0.5 s to 5 s and 0.55%, 1.56%, 7.78%, 14.67%, 13.67%, 7.33% and 7.78% over TMSI from 0.75 s to 5 s. The method outperformed the filter-based decomposition (FB), empirical mode decomposition (EMD) and wavelet decomposition (WT) based CCA for SSVEP recognition. Significance. The results demonstrate the ability of our proposed MEMD-CCA to improve the performance of SSVEP-based BCI.

  15. EEG artifacts reduction by multivariate empirical mode decomposition and multiscale entropy for monitoring depth of anaesthesia during surgery.

    Science.gov (United States)

    Liu, Quan; Chen, Yi-Feng; Fan, Shou-Zen; Abbod, Maysam F; Shieh, Jiann-Shing

    2017-08-01

    Electroencephalography (EEG) has been widely utilized to measure the depth of anaesthesia (DOA) during operation. However, the EEG signals are usually contaminated by artifacts which have a consequence on the measured DOA accuracy. In this study, an effective and useful filtering algorithm based on multivariate empirical mode decomposition and multiscale entropy (MSE) is proposed to measure DOA. Mean entropy of MSE is used as an index to find artifacts-free intrinsic mode functions. The effect of different levels of artifacts on the performances of the proposed filtering is analysed using simulated data. Furthermore, 21 patients' EEG signals are collected and analysed using sample entropy to calculate the complexity for monitoring DOA. The correlation coefficients of entropy and bispectral index (BIS) results show 0.14 ± 0.30 and 0.63 ± 0.09 before and after filtering, respectively. Artificial neural network (ANN) model is used for range mapping in order to correlate the measurements with BIS. The ANN method results show strong correlation coefficient (0.75 ± 0.08). The results in this paper verify that entropy values and BIS have a strong correlation for the purpose of DOA monitoring and the proposed filtering method can effectively filter artifacts from EEG signals. The proposed method performs better than the commonly used wavelet denoising method. This study provides a fully adaptive and automated filter for EEG to measure DOA more accuracy and thus reduce risk related to maintenance of anaesthetic agents.

  16. Discrimination between Newly Formed and Aged Thrombi Using Empirical Mode Decomposition of Ultrasound B-Scan Image

    Directory of Open Access Journals (Sweden)

    Jui Fang

    2015-01-01

    Full Text Available Ultrasound imaging is a first-line diagnostic method for screening the thrombus. During thrombus aging, the proportion of red blood cells (RBCs in the thrombus decreases and therefore the signal intensity of B-scan can be used to detect the thrombus age. To avoid the effect of system gain on the measurements, this study proposed using the empirical mode decomposition (EMD of ultrasound image as a strategy to classify newly formed and aged thrombi. Porcine blood samples were used for the in vitro induction of fresh and aged thrombi (at hematocrits of 40%. Each thrombus was imaged using an ultrasound scanner at different gains (15, 20, and 30 dB. Then, EMD of ultrasound signals was performed to obtain the first and second intrinsic mode functions (IMFs, which were further used to calculate the IMF-based echogenicity ratio (IER. The results showed that the performance of using signal amplitude of B-scan to reflect the thrombus age depends on gain. However, the IER is less affected by the gain in discriminating between fresh and aged thrombi. In the future, ultrasound B-scan combined with the EMD may be used to identify the thrombus age for the establishment of thrombolytic treatment planning.

  17. A Study of Nonstationary Wind Effects on a Full-Scale Large Cooling Tower Using Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    X. X. Cheng

    2017-01-01

    Full Text Available Wind effects on structures obtained by field measurements are often found to be nonstationary, but related researches shared by the wind-engineering community are still limited. In this paper, empirical mode decomposition (EMD is applied to the nonstationary wind pressure time-history samples measured on an actual 167-meter high large cooling tower. It is found that the residue and some intrinsic mode functions (IMFs of low frequencies produced by EMD are responsible for the samples’ nonstationarity. Replacing the residue by the constant mean and subtracting the IMFs of low frequencies can help the nonstationary samples become stationary ones. A further step is taken to compare the loading characteristics extracted from the original nonstationary samples with those extracted from the processed stationary samples. Results indicate that nonstationarity effects on wind loads are notable in most cases. The passive wind tunnel simulation technique based on the assumption of stationarity is also examined, and it is found that the technique is basically conservative for use.

  18. The Removal of EOG Artifacts From EEG Signals Using Independent Component Analysis and Multivariate Empirical Mode Decomposition.

    Science.gov (United States)

    Wang, Gang; Teng, Chaolin; Li, Kuo; Zhang, Zhonglin; Yan, Xiangguo

    2016-09-01

    The recorded electroencephalography (EEG) signals are usually contaminated by electrooculography (EOG) artifacts. In this paper, by using independent component analysis (ICA) and multivariate empirical mode decomposition (MEMD), the ICA-based MEMD method was proposed to remove EOG artifacts (EOAs) from multichannel EEG signals. First, the EEG signals were decomposed by the MEMD into multiple multivariate intrinsic mode functions (MIMFs). The EOG-related components were then extracted by reconstructing the MIMFs corresponding to EOAs. After performing the ICA of EOG-related signals, the EOG-linked independent components were distinguished and rejected. Finally, the clean EEG signals were reconstructed by implementing the inverse transform of ICA and MEMD. The results of simulated and real data suggested that the proposed method could successfully eliminate EOAs from EEG signals and preserve useful EEG information with little loss. By comparing with other existing techniques, the proposed method achieved much improvement in terms of the increase of signal-to-noise and the decrease of mean square error after removing EOAs.

  19. A Combined Methodology to Eliminate Artifacts in Multichannel Electrogastrogram Based on Independent Component Analysis and Ensemble Empirical Mode Decomposition.

    Science.gov (United States)

    Sengottuvel, S; Khan, Pathan Fayaz; Mariyappa, N; Patel, Rajesh; Saipriya, S; Gireesan, K

    2018-06-01

    Cutaneous measurements of electrogastrogram (EGG) signals are heavily contaminated by artifacts due to cardiac activity, breathing, motion artifacts, and electrode drifts whose effective elimination remains an open problem. A common methodology is proposed by combining independent component analysis (ICA) and ensemble empirical mode decomposition (EEMD) to denoise gastric slow-wave signals in multichannel EGG data. Sixteen electrodes are fixed over the upper abdomen to measure the EGG signals under three gastric conditions, namely, preprandial, postprandial immediately, and postprandial 2 h after food for three healthy subjects and a subject with a gastric disorder. Instantaneous frequencies of intrinsic mode functions that are obtained by applying the EEMD technique are analyzed to individually identify and remove each of the artifacts. A critical investigation on the proposed ICA-EEMD method reveals its ability to provide a higher attenuation of artifacts and lower distortion than those obtained by the ICA-EMD method and conventional techniques, like bandpass and adaptive filtering. Characteristic changes in the slow-wave frequencies across the three gastric conditions could be determined from the denoised signals for all the cases. The results therefore encourage the use of the EEMD-based technique for denoising gastric signals to be used in clinical practice.

  20. Single-Trial Classification of Bistable Perception by Integrating Empirical Mode Decomposition, Clustering, and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Hualou Liang

    2008-04-01

    Full Text Available We propose an empirical mode decomposition (EMD- based method to extract features from the multichannel recordings of local field potential (LFP, collected from the middle temporal (MT visual cortex in a macaque monkey, for decoding its bistable structure-from-motion (SFM perception. The feature extraction approach consists of three stages. First, we employ EMD to decompose nonstationary single-trial time series into narrowband components called intrinsic mode functions (IMFs with time scales dependent on the data. Second, we adopt unsupervised K-means clustering to group the IMFs and residues into several clusters across all trials and channels. Third, we use the supervised common spatial patterns (CSP approach to design spatial filters for the clustered spatiotemporal signals. We exploit the support vector machine (SVM classifier on the extracted features to decode the reported perception on a single-trial basis. We demonstrate that the CSP feature of the cluster in the gamma frequency band outperforms the features in other frequency bands and leads to the best decoding performance. We also show that the EMD-based feature extraction can be useful for evoked potential estimation. Our proposed feature extraction approach may have potential for many applications involving nonstationary multivariable time series such as brain-computer interfaces (BCI.

  1. Ultra-High-Speed Travelling Wave Protection of Transmission Line Using Polarity Comparison Principle Based on Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Dong Wang

    2015-01-01

    Full Text Available The traditional polarity comparison based travelling wave protection, using the initial wave information, is affected by initial fault angle, bus structure, and external fault. And the relationship between the magnitude and polarity of travelling wave is ignored. Because of the protection tripping and malfunction, the further application of this protection principle is affected. Therefore, this paper presents an ultra-high-speed travelling wave protection using integral based polarity comparison principle. After empirical mode decomposition of the original travelling wave, the first-order intrinsic mode function is used as protection object. Based on the relationship between the magnitude and polarity of travelling wave, this paper demonstrates the feasibility of using travelling wave magnitude which contains polar information as direction criterion. And the paper integrates the direction criterion in a period after fault to avoid wave head detection failure. Through PSCAD simulation with the typical 500 kV transmission system, the reliability and sensitivity of travelling wave protection were verified under different factors’ affection.

  2. A Cutting Pattern Recognition Method for Shearers Based on Improved Ensemble Empirical Mode Decomposition and a Probabilistic Neural Network

    Directory of Open Access Journals (Sweden)

    Jing Xu

    2015-10-01

    Full Text Available In order to guarantee the stable operation of shearers and promote construction of an automatic coal mining working face, an online cutting pattern recognition method with high accuracy and speed based on Improved Ensemble Empirical Mode Decomposition (IEEMD and Probabilistic Neural Network (PNN is proposed. An industrial microphone is installed on the shearer and the cutting sound is collected as the recognition criterion to overcome the disadvantages of giant size, contact measurement and low identification rate of traditional detectors. To avoid end-point effects and get rid of undesirable intrinsic mode function (IMF components in the initial signal, IEEMD is conducted on the sound. The end-point continuation based on the practical storage data is performed first to overcome the end-point effect. Next the average correlation coefficient, which is calculated by the correlation of the first IMF with others, is introduced to select essential IMFs. Then the energy and standard deviation of the reminder IMFs are extracted as features and PNN is applied to classify the cutting patterns. Finally, a simulation example, with an accuracy of 92.67%, and an industrial application prove the efficiency and correctness of the proposed method.

  3. On Bi-Dimensional Second µ-Variation

    Directory of Open Access Journals (Sweden)

    Ereú Jurancy

    2014-12-01

    Full Text Available In this paper, we present a generalization of the notion of bounded slope variation for functions defined on a rectangle Iba in ℝ2. Given a strictly increasing function µ-defined in a closed real interval, we introduce the class BVµ,2 (Iba , of functions of bounded second µ-variation on Iba ; and show that this class can be equipped with a norm with respect to which it is a Banach space. We also deal with the important case of factorizable functions in BVµ,2 (Iba and finally we exhibit a relation between this class and the one of double Riemann-Stieltjes integrals of functions of bi-dimensional bounded variation.

  4. On the bi-dimensional variational decomposition applied to nonstationary vibration signals for rolling bearing crack detection in coal cutters

    International Nuclear Information System (INIS)

    Jiang, Yu; Li, Zhixiong; Zhang, Chao; Peng, Z; Hu, Chao

    2016-01-01

    This work aims to detect rolling bearing cracks using a variational approach. An original method that appropriately incorporates bi-dimensional variational mode decomposition (BVMD) into discriminant diffusion maps (DDM) is proposed to analyze the nonstationary vibration signals recorded from the cracked rolling bearings in coal cutters. The advantage of this variational decomposition based diffusion map (VDDM) method in comparison to the current DDM is that the intrinsic vibration mode of the crack can be filtered into a limited bandwidth in the frequency domain with an estimated central frequency, thus discarding the interference signal components in the vibration signals and significantly improving the crack detection performance. In addition, the VDDM is able to simultaneously process two-channel sensor signals to reduce information leakage. Experimental validation using rolling bearing crack vibration signals demonstrates that the VDDM separated the raw signals into four intrinsic modes, including one roller vibration mode, one roller cage vibration mode, one inner race vibration mode, and one outer race vibration mode. Hence, reliable fault features were extracted from the outer race vibration mode, and satisfactory crack identification performance was achieved. The comparison between the proposed VDDM and existing approaches indicated that the VDDM method was more efficient and reliable for crack detection in coal cutter rolling bearings. As an effective catalyst for rolling bearing crack detection, this newly proposed method is useful for practical applications. (paper)

  5. High-resolution empirical geomagnetic field model TS07D: Investigating run-on-request and forecasting modes of operation

    Science.gov (United States)

    Stephens, G. K.; Sitnov, M. I.; Ukhorskiy, A. Y.; Vandegriff, J. D.; Tsyganenko, N. A.

    2010-12-01

    The dramatic increase of the geomagnetic field data volume available due to many recent missions, including GOES, Polar, Geotail, Cluster, and THEMIS, required at some point the appropriate qualitative transition in the empirical modeling tools. Classical empirical models, such as T96 and T02, used few custom-tailored modules to represent major magnetospheric current systems and simple data binning or loading-unloading inputs for their fitting with data and the subsequent applications. They have been replaced by more systematic expansions of the equatorial and field-aligned current contributions as well as by the advanced data-mining algorithms searching for events with the global activity parameters, such as the Sym-H index, similar to those at the time of interest, as is done in the model TS07D (Tsyganenko and Sitnov, 2007; Sitnov et al., 2008). The necessity to mine and fit data dynamically, with the individual subset of the database being used to reproduce the geomagnetic field pattern at every new moment in time, requires the corresponding transition in the use of the new empirical geomagnetic field models. It becomes more similar to runs-on-request offered by the Community Coordinated Modeling Center for many first principles MHD and kinetic codes. To provide this mode of operation for the TS07D model a new web-based modeling tool has been created and tested at the JHU/APL (http://geomag_field.jhuapl.edu/model/), and we discuss the first results of its performance testing and validation, including in-sample and out-of-sample modeling of a number of CME- and CIR-driven magnetic storms. We also report on the first tests of the forecasting version of the TS07D model, where the magnetospheric part of the macro-parameters involved in the data-binning process (Sym-H index and its trend parameter) are replaced by their solar wind-based analogs obtained using the Burton-McPherron-Russell approach.

  6. Removal of artifacts in knee joint vibroarthrographic signals using ensemble empirical mode decomposition and detrended fluctuation analysis

    International Nuclear Information System (INIS)

    Wu, Yunfeng; Yang, Shanshan; Zheng, Fang; Cai, Suxian; Lu, Meng; Wu, Meihong

    2014-01-01

    High-resolution knee joint vibroarthrographic (VAG) signals can help physicians accurately evaluate the pathological condition of a degenerative knee joint, in order to prevent unnecessary exploratory surgery. Artifact cancellation is vital to preserve the quality of VAG signals prior to further computer-aided analysis. This paper describes a novel method that effectively utilizes ensemble empirical mode decomposition (EEMD) and detrended fluctuation analysis (DFA) algorithms for the removal of baseline wander and white noise in VAG signal processing. The EEMD method first successively decomposes the raw VAG signal into a set of intrinsic mode functions (IMFs) with fast and low oscillations, until the monotonic baseline wander remains in the last residue. Then, the DFA algorithm is applied to compute the fractal scaling index parameter for each IMF, in order to identify the anti-correlation and the long-range correlation components. Next, the DFA algorithm can be used to identify the anti-correlated and the long-range correlated IMFs, which assists in reconstructing the artifact-reduced VAG signals. Our experimental results showed that the combination of EEMD and DFA algorithms was able to provide averaged signal-to-noise ratio (SNR) values of 20.52 dB (standard deviation: 1.14 dB) and 20.87 dB (standard deviation: 1.89 dB) for 45 normal signals in healthy subjects and 20 pathological signals in symptomatic patients, respectively. The combination of EEMD and DFA algorithms can ameliorate the quality of VAG signals with great SNR improvements over the raw signal, and the results were also superior to those achieved by wavelet matching pursuit decomposition and time-delay neural filter. (paper)

  7. A Hybrid Forecasting Model Based on Empirical Mode Decomposition and the Cuckoo Search Algorithm: A Case Study for Power Load

    Directory of Open Access Journals (Sweden)

    Jiani Heng

    2016-01-01

    Full Text Available Power load forecasting always plays a considerable role in the management of a power system, as accurate forecasting provides a guarantee for the daily operation of the power grid. It has been widely demonstrated in forecasting that hybrid forecasts can improve forecast performance compared with individual forecasts. In this paper, a hybrid forecasting approach, comprising Empirical Mode Decomposition, CSA (Cuckoo Search Algorithm, and WNN (Wavelet Neural Network, is proposed. This approach constructs a more valid forecasting structure and more stable results than traditional ANN (Artificial Neural Network models such as BPNN (Back Propagation Neural Network, GABPNN (Back Propagation Neural Network Optimized by Genetic Algorithm, and WNN. To evaluate the forecasting performance of the proposed model, a half-hourly power load in New South Wales of Australia is used as a case study in this paper. The experimental results demonstrate that the proposed hybrid model is not only simple but also able to satisfactorily approximate the actual power load and can be an effective tool in planning and dispatch for smart grids.

  8. Detection of the ice assertion on aircraft using empirical mode decomposition enhanced by multi-objective optimization

    Science.gov (United States)

    Bagherzadeh, Seyed Amin; Asadi, Davood

    2017-05-01

    In search of a precise method for analyzing nonlinear and non-stationary flight data of an aircraft in the icing condition, an Empirical Mode Decomposition (EMD) algorithm enhanced by multi-objective optimization is introduced. In the proposed method, dissimilar IMF definitions are considered by the Genetic Algorithm (GA) in order to find the best decision parameters of the signal trend. To resolve disadvantages of the classical algorithm caused by the envelope concept, the signal trend is estimated directly in the proposed method. Furthermore, in order to simplify the performance and understanding of the EMD algorithm, the proposed method obviates the need for a repeated sifting process. The proposed enhanced EMD algorithm is verified by some benchmark signals. Afterwards, the enhanced algorithm is applied to simulated flight data in the icing condition in order to detect the ice assertion on the aircraft. The results demonstrate the effectiveness of the proposed EMD algorithm in aircraft ice detection by providing a figure of merit for the icing severity.

  9. Assessment of autonomic nervous system by using empirical mode decomposition-based reflection wave analysis during non-stationary conditions

    International Nuclear Information System (INIS)

    Chang, C C; Hsiao, T C; Kao, S C; Hsu, H Y

    2014-01-01

    Arterial blood pressure (ABP) is an important indicator of cardiovascular circulation and presents various intrinsic regulations. It has been found that the intrinsic characteristics of blood vessels can be assessed quantitatively by ABP analysis (called reflection wave analysis (RWA)), but conventional RWA is insufficient for assessment during non-stationary conditions, such as the Valsalva maneuver. Recently, a novel adaptive method called empirical mode decomposition (EMD) was proposed for non-stationary data analysis. This study proposed a RWA algorithm based on EMD (EMD-RWA). A total of 51 subjects participated in this study, including 39 healthy subjects and 12 patients with autonomic nervous system (ANS) dysfunction. The results showed that EMD-RWA provided a reliable estimation of reflection time in baseline and head-up tilt (HUT). Moreover, the estimated reflection time is able to assess the ANS function non-invasively, both in normal, healthy subjects and in the patients with ANS dysfunction. EMD-RWA provides a new approach for reflection time estimation in non-stationary conditions, and also helps with non-invasive ANS assessment. (paper)

  10. Cooperative phenomena within organised bi-dimensional structures

    International Nuclear Information System (INIS)

    Armand, Franck

    2001-01-01

    In this report produced for an Accreditation to Supervise Research, the author defines a cooperative phenomenon as a phenomenon occurring each time a cooperation between elementary entities results in a collective property which exceeds the simple addition of disorganised individual properties. He reports works and researches which show that such phenomena can be generated by molecular architectures developed in laboratory, but also requires an appropriate organisation of active elementary entities. This can be obtained by self-organisation in solution. However, many applications assume the use of solid phases, and notably thin layers. In this respect, the Langmuir-Blodgett technique and self-assembly are very interesting techniques to produce mono-molecular thin layers, without however controlling molecule in-plane orientation and organisation. The author propose an overview of his works which aimed at obtaining this control, and reports three examples of cooperative phenomena: the generation of a second harmonic, spin transition with hysteresis, and electron conduction (one-dimensional and bi-dimensional electron transfer). The report also contains articles published in various scientific publications, and contributions to congresses [fr

  11. Hybrid Video Coding Based on Bidimensional Matching Pursuit

    Directory of Open Access Journals (Sweden)

    Lorenzo Granai

    2004-12-01

    Full Text Available Hybrid video coding combines together two stages: first, motion estimation and compensation predict each frame from the neighboring frames, then the prediction error is coded, reducing the correlation in the spatial domain. In this work, we focus on the latter stage, presenting a scheme that profits from some of the features introduced by the standard H.264/AVC for motion estimation and replaces the transform in the spatial domain. The prediction error is so coded using the matching pursuit algorithm which decomposes the signal over an appositely designed bidimensional, anisotropic, redundant dictionary. Comparisons are made among the proposed technique, H.264, and a DCT-based coding scheme. Moreover, we introduce fast techniques for atom selection, which exploit the spatial localization of the atoms. An adaptive coding scheme aimed at optimizing the resource allocation is also presented, together with a rate-distortion study for the matching pursuit algorithm. Results show that the proposed scheme outperforms the standard DCT, especially at very low bit rates.

  12. Identification of relationships between climate indices and long-term precipitation in South Korea using ensemble empirical mode decomposition

    Science.gov (United States)

    Kim, Taereem; Shin, Ju-Young; Kim, Sunghun; Heo, Jun-Haeng

    2018-02-01

    Climate indices characterize climate systems and may identify important indicators for long-term precipitation, which are driven by climate interactions in atmosphere-ocean circulation. In this study, we investigated the climate indices that are effective indicators of long-term precipitation in South Korea, and examined their relationships based on statistical methods. Monthly total precipitation was collected from a total of 60 meteorological stations, and they were decomposed by ensemble empirical mode decomposition (EEMD) to identify the inherent oscillating patterns or cycles. Cross-correlation analysis and stepwise variable selection were employed to select the significant climate indices at each station. The climate indices that affect the monthly precipitation in South Korea were identified based on the selection frequencies of the selected indices at all stations. The NINO12 indices with four- and ten-month lags and AMO index with no lag were identified as indicators of monthly precipitation in South Korea. Moreover, they indicate meaningful physical information (e.g. periodic oscillations and long-term trend) inherent in the monthly precipitation. The NINO12 indices with four- and ten- month lags was a strong indicator representing periodic oscillations in monthly precipitation. In addition, the long-term trend of the monthly precipitation could be explained by the AMO index. A multiple linear regression model was constructed to investigate the influences of the identified climate indices on the prediction of monthly precipitation. Three identified climate indices successfully explained the monthly precipitation in the winter dry season. Compared to the monthly precipitation in coastal areas, the monthly precipitation in inland areas showed stronger correlation to the identified climate indices.

  13. Automatic screening of obstructive sleep apnea from the ECG based on empirical mode decomposition and wavelet analysis

    International Nuclear Information System (INIS)

    Mendez, M O; Cerutti, S; Bianchi, A M; Corthout, J; Van Huffel, S; Matteucci, M; Penzel, T

    2010-01-01

    This study analyses two different methods to detect obstructive sleep apnea (OSA) during sleep time based only on the ECG signal. OSA is a common sleep disorder caused by repetitive occlusions of the upper airways, which produces a characteristic pattern on the ECG. ECG features, such as the heart rate variability (HRV) and the QRS peak area, contain information suitable for making a fast, non-invasive and simple screening of sleep apnea. Fifty recordings freely available on Physionet have been included in this analysis, subdivided in a training and in a testing set. We investigated the possibility of using the recently proposed method of empirical mode decomposition (EMD) for this application, comparing the results with the ones obtained through the well-established wavelet analysis (WA). By these decomposition techniques, several features have been extracted from the ECG signal and complemented with a series of standard HRV time domain measures. The best performing feature subset, selected through a sequential feature selection (SFS) method, was used as the input of linear and quadratic discriminant classifiers. In this way we were able to classify the signals on a minute-by-minute basis as apneic or nonapneic with different best-subset sizes, obtaining an accuracy up to 89% with WA and 85% with EMD. Furthermore, 100% correct discrimination of apneic patients from normal subjects was achieved independently of the feature extractor. Finally, the same procedure was repeated by pooling features from standard HRV time domain, EMD and WA together in order to investigate if the two decomposition techniques could provide complementary features. The obtained accuracy was 89%, similarly to the one achieved using only Wavelet analysis as the feature extractor; however, some complementary features in EMD and WA are evident

  14. Holding-based network of nations based on listed energy companies: An empirical study on two-mode affiliation network of two sets of actors

    Science.gov (United States)

    Li, Huajiao; Fang, Wei; An, Haizhong; Gao, Xiangyun; Yan, Lili

    2016-05-01

    Economic networks in the real world are not homogeneous; therefore, it is important to study economic networks with heterogeneous nodes and edges to simulate a real network more precisely. In this paper, we present an empirical study of the one-mode derivative holding-based network constructed by the two-mode affiliation network of two sets of actors using the data of worldwide listed energy companies and their shareholders. First, we identify the primitive relationship in the two-mode affiliation network of the two sets of actors. Then, we present the method used to construct the derivative network based on the shareholding relationship between two sets of actors and the affiliation relationship between actors and events. After constructing the derivative network, we analyze different topological features on the node level, edge level and entire network level and explain the meanings of the different values of the topological features combining the empirical data. This study is helpful for expanding the usage of complex networks to heterogeneous economic networks. For empirical research on the worldwide listed energy stock market, this study is useful for discovering the inner relationships between the nations and regions from a new perspective.

  15. Multiscale Characterization of PM2.5 in Southern Taiwan based on Noise-assisted Multivariate Empirical Mode Decomposition and Time-dependent Intrinsic Correlation

    Science.gov (United States)

    Hsiao, Y. R.; Tsai, C.

    2017-12-01

    As the WHO Air Quality Guideline indicates, ambient air pollution exposes world populations under threat of fatal symptoms (e.g. heart disease, lung cancer, asthma etc.), raising concerns of air pollution sources and relative factors. This study presents a novel approach to investigating the multiscale variations of PM2.5 in southern Taiwan over the past decade, with four meteorological influencing factors (Temperature, relative humidity, precipitation and wind speed),based on Noise-assisted Multivariate Empirical Mode Decomposition(NAMEMD) algorithm, Hilbert Spectral Analysis(HSA) and Time-dependent Intrinsic Correlation(TDIC) method. NAMEMD algorithm is a fully data-driven approach designed for nonlinear and nonstationary multivariate signals, and is performed to decompose multivariate signals into a collection of channels of Intrinsic Mode Functions (IMFs). TDIC method is an EMD-based method using a set of sliding window sizes to quantify localized correlation coefficients for multiscale signals. With the alignment property and quasi-dyadic filter bank of NAMEMD algorithm, one is able to produce same number of IMFs for all variables and estimates the cross correlation in a more accurate way. The performance of spectral representation of NAMEMD-HSA method is compared with Complementary Empirical Mode Decomposition/ Hilbert Spectral Analysis (CEEMD-HSA) and Wavelet Analysis. The nature of NAMAMD-based TDICC analysis is then compared with CEEMD-based TDIC analysis and the traditional correlation analysis.

  16. The Effects of Dimensional Salience, Pretraining Task, and Developmental Level Upon Bidimensional Processing in a Matching Task.

    Science.gov (United States)

    Katsuyama, Ronald M.; Reid, Amy

    Purposes of this study are to determine the effects of (1) preassessed dimensional salience upon performance in a bi-dimensional matching task, and (2) pretraining conditions expected to facilitate bi-dimensional processing. An additional aim was to elucidate a model of development involving changing salience hierarchies by comparing the effects…

  17. Noise Reduction, Atmospheric Pressure Admittance Estimation and Long-Period Component Extraction in Time-Varying Gravity Signals Using Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Linsong Wang

    2015-01-01

    Full Text Available Time-varying gravity signals, with their nonlinear, non-stationary and multi-scale characteristics, record the physical responses of various geodynamic processes and consist of a blend of signals with various periods and amplitudes, corresponding to numerous phenomena. Superconducting gravimeter (SG records are processed in this study using a multi-scale analytical method and corrected for known effects to reduce noise, to study geodynamic phenomena using their gravimetric signatures. Continuous SG (GWR-C032 gravity and barometric data are decomposed into a series of intrinsic mode functions (IMFs using the ensemble empirical mode decomposition (EEMD method, which is proposed to alleviate some unresolved issues (the mode mixing problem and the end effect of the empirical mode decomposition (EMD. Further analysis of the variously scaled signals is based on a dyadic filter bank of the IMFs. The results indicate that removing the high-frequency IMFs can reduce the natural and man-made noise in the data, which are caused by electronic device noise, Earth background noise and the residual effects of pre-processing. The atmospheric admittances based on frequency changes are estimated from the gravity and the atmospheric pressure IMFs in various frequency bands. These time- and frequency-dependent admittance values can be used effectively to improve the atmospheric correction. Using the EEMD method as a filter, the long-period IMFs are extracted from the SG time-varying gravity signals spanning 7 years. The resulting gravity residuals are well correlated with the gravity effect caused by the _ polar motion after correcting for atmospheric effects.

  18. A simple and accurate method for bidimensional position read-out of parallel plate avalanche counters

    International Nuclear Information System (INIS)

    Breskin, A.; Zwang, N.

    1977-01-01

    A simple method for bidimensional position read-out of Parallel Plate Avalanche counters (PPAC) has been developed, using the induced charge technique. An accuracy better than 0.5 mm (FWHM) has been achieved for both coordinates with 5.5. MeV α-particles at gas pressures of 10-40 torr. (author)

  19. New bi-dimensional SPAD arrays for time resolved single photon imaging

    Energy Technology Data Exchange (ETDEWEB)

    Grasso, R. [INFN-Laboratori Nazionali del Sud and Sez., INFN di Catania, Via S. Sofia 62, 95125 Catania (Italy); Dipartimento di Fisica ed Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Viale A. Doria 6, 95125 Catania (Italy); Tudisco, S., E-mail: tudisco@lns.infn.it [INFN-Laboratori Nazionali del Sud and Sez., INFN di Catania, Via S. Sofia 62, 95125 Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Viale A. Doria 6, 95125 Catania (Italy); Piemonte, C. [FBK-Fondazione Bruno Kessler, Via S. Croce 77, 38122 Trento (Italy); Lo Presti, D. [INFN-Laboratori Nazionali del Sud and Sez., INFN di Catania, Via S. Sofia 62, 95125 Catania (Italy); Dipartimento di Fisica ed Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania (Italy); Anzalone, A. [INFN-Laboratori Nazionali del Sud and Sez., INFN di Catania, Via S. Sofia 62, 95125 Catania (Italy); Musumeci, F.; Scordino, A. [INFN-Laboratori Nazionali del Sud and Sez., INFN di Catania, Via S. Sofia 62, 95125 Catania (Italy); Dipartimento di Fisica ed Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania (Italy); Serra, N.; Zorzi, N. [FBK-Fondazione Bruno Kessler, Via S. Croce 77, 38122 Trento (Italy)

    2013-08-01

    Some of the first results concerning the electrical and optical performances of new bi-dimensional single photon avalanche diodes arrays for imaging applications are briefly presented. The planned arrays were realized at the Fondazione Bruno Kessler—Trento and tested at LNS–INFN. The proposed new solution, utilizing a new architecture with integrated quenching resistors, allows to simplify the electronic readout.

  20. New bi-dimensional SPAD arrays for time resolved single photon imaging

    International Nuclear Information System (INIS)

    Grasso, R.; Tudisco, S.; Piemonte, C.; Lo Presti, D.; Anzalone, A.; Musumeci, F.; Scordino, A.; Serra, N.; Zorzi, N.

    2013-01-01

    Some of the first results concerning the electrical and optical performances of new bi-dimensional single photon avalanche diodes arrays for imaging applications are briefly presented. The planned arrays were realized at the Fondazione Bruno Kessler—Trento and tested at LNS–INFN. The proposed new solution, utilizing a new architecture with integrated quenching resistors, allows to simplify the electronic readout

  1. Exploring Multiple Motivations on Urban Residents’ Travel Mode Choices: An Empirical Study from Jiangsu Province in China

    Directory of Open Access Journals (Sweden)

    Jichao Geng

    2017-01-01

    Full Text Available People’s actions are always accompanied with multiple motives. How to estimate the role of the pro-environment motivation under the interference of other motivations will help us to better interpret human environmental behaviors. On the basis of classical motivation theories and travel mode choice research backgrounds, the concepts of pro-environmental and self-interested motivation were defined. Then based on survey data on 1244 urban residents in the Jiangsu Province in China, the multinomial logistic regression model was constructed to examine the effects of multiple motivations, government measures, and demographic characteristics on residents’ travel mode choice behaviors. The result indicates that compared to car use, pro-environmental motivation certainly has a significant and positive role in promoting green travel mode choices (walking, bicycling, and using public transport, but this unstable green behavior is always dominated by self-interested motivations rather than the pro-environmental motivation. In addition, the effects of gender, age, income, vehicle ownership, travel distance, and government instruments show significant differences among travel mode choices. The findings suggest that pro-environmental motivation needs to be stressed and highlighted to ensure sustainable urban transportation. However, policies aimed to only increase the public awareness of environment protection are not enough; tailored policy interventions should be targeted to specific groups having different main motivations.

  2. Calculation of bulk etch rate’s semi-empirical equation for polymer track membranes in stationary and dynamic modes

    Directory of Open Access Journals (Sweden)

    A. Mashentseva

    2013-05-01

    Full Text Available One of the most urgent and extremely social problems in environmental safeties area in Kazakhstan is providing the population of all regions of the country with quality drinking water. Development of filter elements based on nuclear track-etch membranes may be considered as one of best solutions this problem. The values of bulk etch rate and activation energy were calculated in view the effect of temperature, alkaline solution concentration as well as stirring effect. The semi-empirical equation of the bulk etch rate for PET track membranes was calculated. As a result of theoretical and experimental studies a semi-empirical equation of the bulk etch rate VB=3.4∙1012∙C2.07∙exp(-0.825/kT for 12 microns PET film, irradiated by ions 84Kr15+ (energy of 1.75 MeV/nucleon at the heavy ion accelerator DC-60 in Astana branch of the INP NNC RK, was obtained. 

  3. Multi-Fault Diagnosis of Rolling Bearings via Adaptive Projection Intrinsically Transformed Multivariate Empirical Mode Decomposition and High Order Singular Value Decomposition.

    Science.gov (United States)

    Yuan, Rui; Lv, Yong; Song, Gangbing

    2018-04-16

    Rolling bearings are important components in rotary machinery systems. In the field of multi-fault diagnosis of rolling bearings, the vibration signal collected from single channels tends to miss some fault characteristic information. Using multiple sensors to collect signals at different locations on the machine to obtain multivariate signal can remedy this problem. The adverse effect of a power imbalance between the various channels is inevitable, and unfavorable for multivariate signal processing. As a useful, multivariate signal processing method, Adaptive-projection has intrinsically transformed multivariate empirical mode decomposition (APIT-MEMD), and exhibits better performance than MEMD by adopting adaptive projection strategy in order to alleviate power imbalances. The filter bank properties of APIT-MEMD are also adopted to enable more accurate and stable intrinsic mode functions (IMFs), and to ease mode mixing problems in multi-fault frequency extractions. By aligning IMF sets into a third order tensor, high order singular value decomposition (HOSVD) can be employed to estimate the fault number. The fault correlation factor (FCF) analysis is used to conduct correlation analysis, in order to determine effective IMFs; the characteristic frequencies of multi-faults can then be extracted. Numerical simulations and the application of multi-fault situation can demonstrate that the proposed method is promising in multi-fault diagnoses of multivariate rolling bearing signal.

  4. Patient-Specific Seizure Detection in Long-Term EEG Using Signal-Derived Empirical Mode Decomposition (EMD)-based Dictionary Approach.

    Science.gov (United States)

    Kaleem, Muhammad; Gurve, Dharmendra; Guergachi, Aziz; Krishnan, Sridhar

    2018-06-25

    The objective of the work described in this paper is development of a computationally efficient methodology for patient-specific automatic seizure detection in long-term multi-channel EEG recordings. Approach: A novel patient-specific seizure detection approach based on signal-derived Empirical Mode Decomposition (EMD)-based dictionary approach is proposed. For this purpose, we use an empirical framework for EMD-based dictionary creation and learning, inspired by traditional dictionary learning methods, in which the EMD-based dictionary is learned from the multi-channel EEG data being analyzed for automatic seizure detection. We present the algorithm for dictionary creation and learning, whose purpose is to learn dictionaries with a small number of atoms. Using training signals belonging to seizure and non-seizure classes, an initial dictionary, termed as the raw dictionary, is formed. The atoms of the raw dictionary are composed of intrinsic mode functions obtained after decomposition of the training signals using the empirical mode decomposition algorithm. The raw dictionary is then trained using a learning algorithm, resulting in a substantial decrease in the number of atoms in the trained dictionary. The trained dictionary is then used for automatic seizure detection, such that coefficients of orthogonal projections of test signals against the trained dictionary form the features used for classification of test signals into seizure and non-seizure classes. Thus no hand-engineered features have to be extracted from the data as in traditional seizure detection approaches. Main results: The performance of the proposed approach is validated using the CHB-MIT benchmark database, and averaged accuracy, sensitivity and specificity values of 92.9%, 94.3% and 91.5%, respectively, are obtained using support vector machine classifier and five-fold cross-validation method. These results are compared with other approaches using the same database, and the suitability

  5. Daily Peak Load Forecasting Based on Complete Ensemble Empirical Mode Decomposition with Adaptive Noise and Support Vector Machine Optimized by Modified Grey Wolf Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Shuyu Dai

    2018-01-01

    Full Text Available Daily peak load forecasting is an important part of power load forecasting. The accuracy of its prediction has great influence on the formulation of power generation plan, power grid dispatching, power grid operation and power supply reliability of power system. Therefore, it is of great significance to construct a suitable model to realize the accurate prediction of the daily peak load. A novel daily peak load forecasting model, CEEMDAN-MGWO-SVM (Complete Ensemble Empirical Mode Decomposition with Adaptive Noise and Support Vector Machine Optimized by Modified Grey Wolf Optimization Algorithm, is proposed in this paper. Firstly, the model uses the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN algorithm to decompose the daily peak load sequence into multiple sub sequences. Then, the model of modified grey wolf optimization and support vector machine (MGWO-SVM is adopted to forecast the sub sequences. Finally, the forecasting sequence is reconstructed and the forecasting result is obtained. Using CEEMDAN can realize noise reduction for non-stationary daily peak load sequence, which makes the daily peak load sequence more regular. The model adopts the grey wolf optimization algorithm improved by introducing the population dynamic evolution operator and the nonlinear convergence factor to enhance the global search ability and avoid falling into the local optimum, which can better optimize the parameters of the SVM algorithm for improving the forecasting accuracy of daily peak load. In this paper, three cases are used to test the forecasting accuracy of the CEEMDAN-MGWO-SVM model. We choose the models EEMD-MGWO-SVM (Ensemble Empirical Mode Decomposition and Support Vector Machine Optimized by Modified Grey Wolf Optimization Algorithm, MGWO-SVM (Support Vector Machine Optimized by Modified Grey Wolf Optimization Algorithm, GWO-SVM (Support Vector Machine Optimized by Grey Wolf Optimization Algorithm, SVM (Support Vector

  6. DIMCO. A new system for mechanical and bidimensional of nuclear fuel pins

    International Nuclear Information System (INIS)

    Moreno, A.

    1977-01-01

    The system developed in JEN, for: the mechanical analysis uni and bidimensional, of nuclear fuels is presented. The mathematical and numerical foundations used, are here described. And so the models developed for effects such as swelling, cracking, clad growth etc. Numerical results for several cases are presented. a) Numerical test in one and two dimensions. b) Applicability range, c) Interaction effects. d) Influence of the power history. (Author) 17 refs

  7. Better Fire Emissions Estimates for Tricky Species Illustrated with a Simple Empirical Burn-to-Sample Plume Mode

    Science.gov (United States)

    Chatfield, R. B.; Andreae, M. O.; Lareau, N.

    2017-12-01

    Methodologies for estimating emission factors (EFs) and broader emission relationship (ERs) (for e.g., O3 production or aerosol absorption) have been difficult to make accurate and convincing; this is largely due to non-fire effects on both CO2 and also fire-emitted trace species. We present a new view of these multiple effects as they affect downwind tracer samples observed by aircraft in NASA's ARCTAS and SEAC4RS airborne missions. This view leads to our method for estimates of ERs and EFs that allow spatially detailed views focusing on individual samples, a Mixed Effects Emission Ratio Technique (MERET). We concentrate on presenting a generalized viewpoint: a simple idealized model of a fire plume entraining air from near-flames upward and then outward to a sampling point, a view base on observations of typical situations. Actual evolution of a plume can depend intricately on the fully history of entrainment, entraining concentration levels of CO2 and tracer species, and mixing. Observations suggest that our simple plume model with just two (analyzed) values for entrained CO2 and one or potentially two values for environmental concentrations for each tracer can serve surprisingly well for mixed-effects regression estimates. Such details appears imperative for long-lived gases like CH4, CO, and N2O. In particular, it is difficult to distinguish fire-sourced emissions from air entrained near the flames, entrained in a way proportional to fire intensity. These entraining concentrations may vary significantly from those later in plume evolution. In addition, such detail also highlights behavior of emissions that react on the path to sampling, e.g. fire-sourced or entrained urban NOx. Some caveats regarding poor sampling situations, and some warning signs, based on this empirical plume description and on MERET analyses, are demonstrated. Some information is available when multiple tracers are analyzed. MERET estimates for ERs of short and these long-lived species are

  8. Forecasting of Energy Consumption in China Based on Ensemble Empirical Mode Decomposition and Least Squares Support Vector Machine Optimized by Improved Shuffled Frog Leaping Algorithm

    Directory of Open Access Journals (Sweden)

    Shuyu Dai

    2018-04-01

    Full Text Available For social development, energy is a crucial material whose consumption affects the stable and sustained development of the natural environment and economy. Currently, China has become the largest energy consumer in the world. Therefore, establishing an appropriate energy consumption prediction model and accurately forecasting energy consumption in China have practical significance, and can provide a scientific basis for China to formulate a reasonable energy production plan and energy-saving and emissions-reduction-related policies to boost sustainable development. For forecasting the energy consumption in China accurately, considering the main driving factors of energy consumption, a novel model, EEMD-ISFLA-LSSVM (Ensemble Empirical Mode Decomposition and Least Squares Support Vector Machine Optimized by Improved Shuffled Frog Leaping Algorithm, is proposed in this article. The prediction accuracy of energy consumption is influenced by various factors. In this article, first considering population, GDP (Gross Domestic Product, industrial structure (the proportion of the second industry added value, energy consumption structure, energy intensity, carbon emissions intensity, total imports and exports and other influencing factors of energy consumption, the main driving factors of energy consumption are screened as the model input according to the sorting of grey relational degrees to realize feature dimension reduction. Then, the original energy consumption sequence of China is decomposed into multiple subsequences by Ensemble Empirical Mode Decomposition for de-noising. Next, the ISFLA-LSSVM (Least Squares Support Vector Machine Optimized by Improved Shuffled Frog Leaping Algorithm model is adopted to forecast each subsequence, and the prediction sequences are reconstructed to obtain the forecasting result. After that, the data from 1990 to 2009 are taken as the training set, and the data from 2010 to 2016 are taken as the test set to make an

  9. 企业设计战略模式的理论与实证研究%Theoretical and Empirical Study on Enterprise Design Strategy Mode

    Institute of Scientific and Technical Information of China (English)

    管顺丰; 肖雄; 李燕敏

    2016-01-01

    针对设计战略理论发展的需要,在系统总结国内外设计战略模式研究现状的基础上,从目标市场、产品定位、业务领域三个层面构建了设计战略模式体系(即价值创新战略、标准化战略、本土化战略、全球化战略、业务领域多元化战略以及业务领域集中化战略等),进而分析探讨了各种设计战略模式的特征和实施途径。最后将苹果公司和摩托罗拉公司作为案例进行了实证研究。%According to the needs of the development of design strategy theory, and from the levels of target market, product positioning, and business system, the design strategy model is constructed (that is, the value innovation strategy, standardization strategy, localization strategy, globalization strategy, diversiifed business strategy and business focus strategy, etc.), and then this paper analyze the features of various design strategic mode and implementation ways. Finally this paper makes a empirical study on the design strategic mode of APPLE Inc. and MOTOROLA Inc.

  10. Extraction Method of Driver’s Mental Component Based on Empirical Mode Decomposition and Approximate Entropy Statistic Characteristic in Vehicle Running State

    Directory of Open Access Journals (Sweden)

    Shuan-Feng Zhao

    2017-01-01

    Full Text Available In the driver fatigue monitoring technology, the essence is to capture and analyze the driver behavior information, such as eyes, face, heart, and EEG activity during driving. However, ECG and EEG monitoring are limited by the installation electrodes and are not commercially available. The most common fatigue detection method is the analysis of driver behavior, that is, to determine whether the driver is tired by recording and analyzing the behavior characteristics of steering wheel and brake. The driver usually adjusts his or her actions based on the observed road conditions. Obviously the road path information is directly contained in the vehicle driving state; if you want to judge the driver’s driving behavior by vehicle driving status information, the first task is to remove the road information from the vehicle driving state data. Therefore, this paper proposes an effective intrinsic mode function selection method for the approximate entropy of empirical mode decomposition considering the characteristics of the frequency distribution of road and vehicle information and the unsteady and nonlinear characteristics of the driver closed-loop driving system in vehicle driving state data. The objective is to extract the effective component of the driving behavior information and to weaken the road information component. Finally the effectiveness of the proposed method is verified by simulating driving experiments.

  11. A Novel Hybrid Data-Driven Model for Daily Land Surface Temperature Forecasting Using Long Short-Term Memory Neural Network Based on Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Xike Zhang

    2018-05-01

    Full Text Available Daily land surface temperature (LST forecasting is of great significance for application in climate-related, agricultural, eco-environmental, or industrial studies. Hybrid data-driven prediction models using Ensemble Empirical Mode Composition (EEMD coupled with Machine Learning (ML algorithms are useful for achieving these purposes because they can reduce the difficulty of modeling, require less history data, are easy to develop, and are less complex than physical models. In this article, a computationally simple, less data-intensive, fast and efficient novel hybrid data-driven model called the EEMD Long Short-Term Memory (LSTM neural network, namely EEMD-LSTM, is proposed to reduce the difficulty of modeling and to improve prediction accuracy. The daily LST data series from the Mapoling and Zhijaing stations in the Dongting Lake basin, central south China, from 1 January 2014 to 31 December 2016 is used as a case study. The EEMD is firstly employed to decompose the original daily LST data series into many Intrinsic Mode Functions (IMFs and a single residue item. Then, the Partial Autocorrelation Function (PACF is used to obtain the number of input data sample points for LSTM models. Next, the LSTM models are constructed to predict the decompositions. All the predicted results of the decompositions are aggregated as the final daily LST. Finally, the prediction performance of the hybrid EEMD-LSTM model is assessed in terms of the Mean Square Error (MSE, Mean Absolute Error (MAE, Mean Absolute Percentage Error (MAPE, Root Mean Square Error (RMSE, Pearson Correlation Coefficient (CC and Nash-Sutcliffe Coefficient of Efficiency (NSCE. To validate the hybrid data-driven model, the hybrid EEMD-LSTM model is compared with the Recurrent Neural Network (RNN, LSTM and Empirical Mode Decomposition (EMD coupled with RNN, EMD-LSTM and EEMD-RNN models, and their comparison results demonstrate that the hybrid EEMD-LSTM model performs better than the other

  12. A Novel Hybrid Data-Driven Model for Daily Land Surface Temperature Forecasting Using Long Short-Term Memory Neural Network Based on Ensemble Empirical Mode Decomposition.

    Science.gov (United States)

    Zhang, Xike; Zhang, Qiuwen; Zhang, Gui; Nie, Zhiping; Gui, Zifan; Que, Huafei

    2018-05-21

    Daily land surface temperature (LST) forecasting is of great significance for application in climate-related, agricultural, eco-environmental, or industrial studies. Hybrid data-driven prediction models using Ensemble Empirical Mode Composition (EEMD) coupled with Machine Learning (ML) algorithms are useful for achieving these purposes because they can reduce the difficulty of modeling, require less history data, are easy to develop, and are less complex than physical models. In this article, a computationally simple, less data-intensive, fast and efficient novel hybrid data-driven model called the EEMD Long Short-Term Memory (LSTM) neural network, namely EEMD-LSTM, is proposed to reduce the difficulty of modeling and to improve prediction accuracy. The daily LST data series from the Mapoling and Zhijaing stations in the Dongting Lake basin, central south China, from 1 January 2014 to 31 December 2016 is used as a case study. The EEMD is firstly employed to decompose the original daily LST data series into many Intrinsic Mode Functions (IMFs) and a single residue item. Then, the Partial Autocorrelation Function (PACF) is used to obtain the number of input data sample points for LSTM models. Next, the LSTM models are constructed to predict the decompositions. All the predicted results of the decompositions are aggregated as the final daily LST. Finally, the prediction performance of the hybrid EEMD-LSTM model is assessed in terms of the Mean Square Error (MSE), Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE), Root Mean Square Error (RMSE), Pearson Correlation Coefficient (CC) and Nash-Sutcliffe Coefficient of Efficiency (NSCE). To validate the hybrid data-driven model, the hybrid EEMD-LSTM model is compared with the Recurrent Neural Network (RNN), LSTM and Empirical Mode Decomposition (EMD) coupled with RNN, EMD-LSTM and EEMD-RNN models, and their comparison results demonstrate that the hybrid EEMD-LSTM model performs better than the other five

  13. Radiographic comparison of apical root resorption after orthodontic treatment between bidimensional and Roth straight-wire techniques.

    Science.gov (United States)

    Zawawi, Khalid H; Malki, Ghadah A

    2014-10-01

    The aim of this study was to compare the amount of root resorption after orthodontic treatment between the bidimensional and the Roth straight-wire techniques. Another objective was to compare the amount of root resorption in the whole sample studied and record the prevalence of root resorption. The sample consisted of 40 patients (age ranged between 11 and 18 years) with Angle Class II division 1 malocclusions, treated nonextraction. Twenty patients were treated with bidimensional technique and 20 with a 0.018-inch Roth straight-wire technique. Root lengths of the maxillary incisors were measured on pre- and post-treatment periapical radiographs. The results demonstrated that the bidimensional and Roth straight-wire groups showed significant root resorption after treatment, 1.11 (0.17) and 0.86 (0.05), respectively, P root shortening between the bidimensional and Roth straight-wire groups, there was no significant difference between the mean change from pre- to post-treatment between bidimensional group (mean = 1.00 ± 1.34) and Roth straight-wire group (mean = 0.88 ± 0.86), P = 0.63. Considering the whole sample, there was no root resoprtion in 32.5% of the analysed teeth. There was only mild resorption in 56.2%, moderate in 8.8% and severe in only 2.5% of the teeth. Treatment with the bidimensional technique did not produce an increase in the amount of root resorption. The prevalence and amount of root resorption was similar between bidimensional and Roth straight-wire techniques.

  14. A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering.

    Science.gov (United States)

    Shen, Chong; Li, Jie; Zhang, Xiaoming; Shi, Yunbo; Tang, Jun; Cao, Huiliang; Liu, Jun

    2016-05-31

    The different noise components in a dual-mass micro-electromechanical system (MEMS) gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN), electronic-thermal noise (ETN), flicker noise (FN) and Coriolis signal in-phase noise (IPN). The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD) and time-frequency peak filtering (TFPF). There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs) by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods.

  15. A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering

    Directory of Open Access Journals (Sweden)

    Chong Shen

    2016-05-01

    Full Text Available The different noise components in a dual-mass micro-electromechanical system (MEMS gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN, electronic-thermal noise (ETN, flicker noise (FN and Coriolis signal in-phase noise (IPN. The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD and time-frequency peak filtering (TFPF. There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods.

  16. Analysis of the Nonlinear Trends and Non-Stationary Oscillations of Regional Precipitation in Xinjiang, Northwestern China, Using Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Bin Guo

    2016-03-01

    Full Text Available Changes in precipitation could have crucial influences on the regional water resources in arid regions such as Xinjiang. It is necessary to understand the intrinsic multi-scale variations of precipitation in different parts of Xinjiang in the context of climate change. In this study, based on precipitation data from 53 meteorological stations in Xinjiang during 1960–2012, we investigated the intrinsic multi-scale characteristics of precipitation variability using an adaptive method named ensemble empirical mode decomposition (EEMD. Obvious non-linear upward trends in precipitation were found in the north, south, east and the entire Xinjiang. Changes in precipitation in Xinjiang exhibited significant inter-annual scale (quasi-2 and quasi-6 years and inter-decadal scale (quasi-12 and quasi-23 years. Moreover, the 2–3-year quasi-periodic fluctuation was dominant in regional precipitation and the inter-annual variation had a considerable effect on the regional-scale precipitation variation in Xinjiang. We also found that there were distinctive spatial differences in variation trends and turning points of precipitation in Xinjiang. The results of this study indicated that compared to traditional decomposition methods, the EEMD method, without using any a priori determined basis functions, could effectively extract the reliable multi-scale fluctuations and reveal the intrinsic oscillation properties of climate elements.

  17. Analysis of the Nonlinear Trends and Non-Stationary Oscillations of Regional Precipitation in Xinjiang, Northwestern China, Using Ensemble Empirical Mode Decomposition.

    Science.gov (United States)

    Guo, Bin; Chen, Zhongsheng; Guo, Jinyun; Liu, Feng; Chen, Chuanfa; Liu, Kangli

    2016-03-21

    Changes in precipitation could have crucial influences on the regional water resources in arid regions such as Xinjiang. It is necessary to understand the intrinsic multi-scale variations of precipitation in different parts of Xinjiang in the context of climate change. In this study, based on precipitation data from 53 meteorological stations in Xinjiang during 1960-2012, we investigated the intrinsic multi-scale characteristics of precipitation variability using an adaptive method named ensemble empirical mode decomposition (EEMD). Obvious non-linear upward trends in precipitation were found in the north, south, east and the entire Xinjiang. Changes in precipitation in Xinjiang exhibited significant inter-annual scale (quasi-2 and quasi-6 years) and inter-decadal scale (quasi-12 and quasi-23 years). Moreover, the 2-3-year quasi-periodic fluctuation was dominant in regional precipitation and the inter-annual variation had a considerable effect on the regional-scale precipitation variation in Xinjiang. We also found that there were distinctive spatial differences in variation trends and turning points of precipitation in Xinjiang. The results of this study indicated that compared to traditional decomposition methods, the EEMD method, without using any a priori determined basis functions, could effectively extract the reliable multi-scale fluctuations and reveal the intrinsic oscillation properties of climate elements.

  18. A non-destructive surface burn detection method for ferrous metals based on acoustic emission and ensemble empirical mode decomposition: from laser simulation to grinding process

    International Nuclear Information System (INIS)

    Yang, Zhensheng; Wu, Haixi; Yu, Zhonghua; Huang, Youfang

    2014-01-01

    Grinding is usually done in the final finishing of a component. As a result, the surface quality of finished products, e.g., surface roughness, hardness and residual stress, are affected by the grinding procedure. However, the lack of methods for monitoring of grinding makes it difficult to control the quality of the process. This paper focuses on the monitoring approaches for the surface burn phenomenon in grinding. A non-destructive burn detection method based on acoustic emission (AE) and ensemble empirical mode decomposition (EEMD) was proposed for this purpose. To precisely extract the AE features caused by phase transformation during burn formation, artificial burn was produced to mimic grinding burn by means of laser irradiation, since laser-induced burn involves less mechanical and electrical noise. The burn formation process was monitored by an AE sensor. The frequency band ranging from 150 to 400 kHz was believed to be related to surface burn formation in the laser irradiation process. The burn-sensitive frequency band was further used to instruct feature extraction during the grinding process based on EEMD. Linear classification results evidenced a distinct margin between samples with and without surface burn. This work provides a practical means for grinding burn detection. (paper)

  19. Non-linear multivariate and multiscale monitoring and signal denoising strategy using Kernel Principal Component Analysis combined with Ensemble Empirical Mode Decomposition method

    Science.gov (United States)

    Žvokelj, Matej; Zupan, Samo; Prebil, Ivan

    2011-10-01

    The article presents a novel non-linear multivariate and multiscale statistical process monitoring and signal denoising method which combines the strengths of the Kernel Principal Component Analysis (KPCA) non-linear multivariate monitoring approach with the benefits of Ensemble Empirical Mode Decomposition (EEMD) to handle multiscale system dynamics. The proposed method which enables us to cope with complex even severe non-linear systems with a wide dynamic range was named the EEMD-based multiscale KPCA (EEMD-MSKPCA). The method is quite general in nature and could be used in different areas for various tasks even without any really deep understanding of the nature of the system under consideration. Its efficiency was first demonstrated by an illustrative example, after which the applicability for the task of bearing fault detection, diagnosis and signal denosing was tested on simulated as well as actual vibration and acoustic emission (AE) signals measured on purpose-built large-size low-speed bearing test stand. The positive results obtained indicate that the proposed EEMD-MSKPCA method provides a promising tool for tackling non-linear multiscale data which present a convolved picture of many events occupying different regions in the time-frequency plane.

  20. Bidimensional microdosimetry as a tool for evaluating biological response and target structure

    International Nuclear Information System (INIS)

    Booz, J.; Schmitz, Th.; Feinendegen, L.E.; Olko, P.

    1992-01-01

    The paper addresses the issue of the relevance of microdosimetric spectra for quantifying the effects of low-level exposures to radiation. Biological response functions derived to date from numerical analyses of radiobiological and microdosimetric observations refer to uniform targets of a preassumed size. The characteristic two-modal shape of functions obtained for several endpoints reflects the importance of two different pathways of damage formation, each of them related in fact to different target sizes. The correlated energy deposition distributions in such a bidimensional system are suggested as a more appropriate physical input for analysing biological response and target structure. (author)

  1. Magneto-transporte em sistemas semicondutores com gas de eletrons bidimensional

    OpenAIRE

    Alvaro Guedes Soares

    1994-01-01

    Resumo: O objetivo básico deste trabalho foi a implantação de técnicas de magneto-transporte em heteroestruturas semicondutoras que apresentam gás de elétron bidimensional (2-DEG), particularmente, o Efeito Shubnikov-de Haas (SdH) e Efeito Hall Quântico (QHE). Neste sentido foi realizada a recuperação de uma bobina supercondutora (criostato e sistema de controle) que permite medidas em campo magnético de até 14 Tesla. Medidas de oscilações Shubnikov-de Haas e Efeito Hall Quântico foram fei...

  2. Strain detection in crystalline heterostructures using bidimensional blocking patterns of channelled particles

    Science.gov (United States)

    Redondo-Cubero, A.; David-Bosne, E.; Wahl, U.; Miranda, P.; da Silva, M. R.; Correia, J. G.; Lorenz, K.

    2018-03-01

    Strain is a critical parameter affecting the growth and the performance of many semiconductor systems but, at the same time, the accurate determination of strain profiles in heterostructures can be challenging, especially at the nanoscale. Ion channelling/blocking is a powerful technique for the detection of the strain state of thin films, normally carried out through angular scans with conventional particle detectors. Here we report the novel application of position sensitive detectors for the evaluation of the strain in a series of AlInN/GaN heterostructures with different compositions and thicknesses. The tetragonal strain is varied from compressive to tensile and analysed through bidimensional blocking patterns. The results demonstrate that strain can be correctly quantified when compared to Monte Carlo channelling simulations, which are essential because of the presence of ion steering effects at the interface between the layer and the substrate. Despite this physical limitation caused by ion steering, our results show that full bidimensional patterns can be applied to detect fingerprints and enhance the accuracy for most critical cases, in which the angular shift associated to the lattice distortion is below the critical angle for channelling.

  3. Instantaneous 3D EEG Signal Analysis Based on Empirical Mode Decomposition and the Hilbert–Huang Transform Applied to Depth of Anaesthesia

    Directory of Open Access Journals (Sweden)

    Mu-Tzu Shih

    2015-02-01

    Full Text Available Depth of anaesthesia (DoA is an important measure for assessing the degree to which the central nervous system of a patient is depressed by a general anaesthetic agent, depending on the potency and concentration with which anaesthesia is administered during surgery. We can monitor the DoA by observing the patient’s electroencephalography (EEG signals during the surgical procedure. Typically high frequency EEG signals indicates the patient is conscious, while low frequency signals mean the patient is in a general anaesthetic state. If the anaesthetist is able to observe the instantaneous frequency changes of the patient’s EEG signals during surgery this can help to better regulate and monitor DoA, reducing surgical and post-operative risks. This paper describes an approach towards the development of a 3D real-time visualization application which can show the instantaneous frequency and instantaneous amplitude of EEG simultaneously by using empirical mode decomposition (EMD and the Hilbert–Huang transform (HHT. HHT uses the EMD method to decompose a signal into so-called intrinsic mode functions (IMFs. The Hilbert spectral analysis method is then used to obtain instantaneous frequency data. The HHT provides a new method of analyzing non-stationary and nonlinear time series data. We investigate this approach by analyzing EEG data collected from patients undergoing surgical procedures. The results show that the EEG differences between three distinct surgical stages computed by using sample entropy (SampEn are consistent with the expected differences between these stages based on the bispectral index (BIS, which has been shown to be quantifiable measure of the effect of anaesthetics on the central nervous system. Also, the proposed filtering approach is more effective compared to the standard filtering method in filtering out signal noise resulting in more consistent results than those provided by the BIS. The proposed approach is therefore

  4. The complexity of standing postural control in older adults: a modified detrended fluctuation analysis based upon the empirical mode decomposition algorithm.

    Directory of Open Access Journals (Sweden)

    Junhong Zhou

    Full Text Available Human aging into senescence diminishes the capacity of the postural control system to adapt to the stressors of everyday life. Diminished adaptive capacity may be reflected by a loss of the fractal-like, multiscale complexity within the dynamics of standing postural sway (i.e., center-of-pressure, COP. We therefore studied the relationship between COP complexity and adaptive capacity in 22 older and 22 younger healthy adults. COP magnitude dynamics were assessed from raw data during quiet standing with eyes open and closed, and complexity was quantified with a new technique termed empirical mode decomposition embedded detrended fluctuation analysis (EMD-DFA. Adaptive capacity of the postural control system was assessed with the sharpened Romberg test. As compared to traditional DFA, EMD-DFA more accurately identified trends in COP data with intrinsic scales and produced short and long-term scaling exponents (i.e., α(Short, α(Long with greater reliability. The fractal-like properties of COP fluctuations were time-scale dependent and highly complex (i.e., α(Short values were close to one over relatively short time scales. As compared to younger adults, older adults demonstrated lower short-term COP complexity (i.e., greater α(Short values in both visual conditions (p>0.001. Closing the eyes decreased short-term COP complexity, yet this decrease was greater in older compared to younger adults (p<0.001. In older adults, those with higher short-term COP complexity exhibited better adaptive capacity as quantified by Romberg test performance (r(2 = 0.38, p<0.001. These results indicate that an age-related loss of COP complexity of magnitude series may reflect a clinically important reduction in postural control system functionality as a new biomarker.

  5. Application of Multivariate Empirical Mode Decomposition and Sample Entropy in EEG Signals via Artificial Neural Networks for Interpreting Depth of Anesthesia

    Directory of Open Access Journals (Sweden)

    Jiann-Shing Shieh

    2013-08-01

    Full Text Available EEG (Electroencephalography signals can express the human awareness activities and consequently it can indicate the depth of anesthesia. On the other hand, Bispectral-index (BIS is often used as an indicator to assess the depth of anesthesia. This study is aimed at using an advanced signal processing method to analyze EEG signals and compare them with existing BIS indexes from a commercial product (i.e., IntelliVue MP60 BIS module. Multivariate empirical mode decomposition (MEMD algorithm is utilized to filter the EEG signals. A combination of two MEMD components (IMF2 + IMF3 is used to express the raw EEG. Then, sample entropy algorithm is used to calculate the complexity of the patients’ EEG signal. Furthermore, linear regression and artificial neural network (ANN methods were used to model the sample entropy using BIS index as the gold standard. ANN can produce better target value than linear regression. The correlation coefficient is 0.790 ± 0.069 and MAE is 8.448 ± 1.887. In conclusion, the area under the receiver operating characteristic (ROC curve (AUC of sample entropy value using ANN and MEMD is 0.969 ± 0.028 while the AUC of sample entropy value without filter is 0.733 ± 0.123. It means the MEMD method can filter out noise of the brain waves, so that the sample entropy of EEG can be closely related to the depth of anesthesia. Therefore, the resulting index can be adopted as the reference for the physician, in order to reduce the risk of surgery.

  6. Application of the bidimensional ion-exchange chromatography for the laboratory preparation of different 15N enrichments and depletions

    International Nuclear Information System (INIS)

    Farjo, K.

    1989-01-01

    The ion-exchange application of the bidimensional solid/liquid technique for the preparation of different 15 N-abundances utilizing the isotope exchange system NH 4 + /NH 3 · aq is reported and the application of the technique for the separation of nitrogen isotopes is briefly discussed. (author)

  7. Automatic sleep staging using empirical mode decomposition, discrete wavelet transform, time-domain, and nonlinear dynamics features of heart rate variability signals.

    Science.gov (United States)

    Ebrahimi, Farideh; Setarehdan, Seyed-Kamaledin; Ayala-Moyeda, Jose; Nazeran, Homer

    2013-10-01

    The conventional method for sleep staging is to analyze polysomnograms (PSGs) recorded in a sleep lab. The electroencephalogram (EEG) is one of the most important signals in PSGs but recording and analysis of this signal presents a number of technical challenges, especially at home. Instead, electrocardiograms (ECGs) are much easier to record and may offer an attractive alternative for home sleep monitoring. The heart rate variability (HRV) signal proves suitable for automatic sleep staging. Thirty PSGs from the Sleep Heart Health Study (SHHS) database were used. Three feature sets were extracted from 5- and 0.5-min HRV segments: time-domain features, nonlinear-dynamics features and time-frequency features. The latter was achieved by using empirical mode decomposition (EMD) and discrete wavelet transform (DWT) methods. Normalized energies in important frequency bands of HRV signals were computed using time-frequency methods. ANOVA and t-test were used for statistical evaluations. Automatic sleep staging was based on HRV signal features. The ANOVA followed by a post hoc Bonferroni was used for individual feature assessment. Most features were beneficial for sleep staging. A t-test was used to compare the means of extracted features in 5- and 0.5-min HRV segments. The results showed that the extracted features means were statistically similar for a small number of features. A separability measure showed that time-frequency features, especially EMD features, had larger separation than others. There was not a sizable difference in separability of linear features between 5- and 0.5-min HRV segments but separability of nonlinear features, especially EMD features, decreased in 0.5-min HRV segments. HRV signal features were classified by linear discriminant (LD) and quadratic discriminant (QD) methods. Classification results based on features from 5-min segments surpassed those obtained from 0.5-min segments. The best result was obtained from features using 5-min HRV

  8. Displacement prediction of Baijiabao landslide based on empirical mode decomposition and long short-term memory neural network in Three Gorges area, China

    Science.gov (United States)

    Xu, Shiluo; Niu, Ruiqing

    2018-02-01

    Every year, landslides pose huge threats to thousands of people in China, especially those in the Three Gorges area. It is thus necessary to establish an early warning system to help prevent property damage and save peoples' lives. Most of the landslide displacement prediction models that have been proposed are static models. However, landslides are dynamic systems. In this paper, the total accumulative displacement of the Baijiabao landslide is divided into trend and periodic components using empirical mode decomposition. The trend component is predicted using an S-curve estimation, and the total periodic component is predicted using a long short-term memory neural network (LSTM). LSTM is a dynamic model that can remember historical information and apply it to the current output. Six triggering factors are chosen to predict the periodic term using the Pearson cross-correlation coefficient and mutual information. These factors include the cumulative precipitation during the previous month, the cumulative precipitation during a two-month period, the reservoir level during the current month, the change in the reservoir level during the previous month, the cumulative increment of the reservoir level during the current month, and the cumulative displacement during the previous month. When using one-step-ahead prediction, LSTM yields a root mean squared error (RMSE) value of 6.112 mm, while the support vector machine for regression (SVR) and the back-propagation neural network (BP) yield values of 10.686 mm and 8.237 mm, respectively. Meanwhile, the Elman network (Elman) yields an RMSE value of 6.579 mm. In addition, when using multi-step-ahead prediction, LSTM obtains an RMSE value of 8.648 mm, while SVR, BP and the Elman network obtains RSME values of 13.418 mm, 13.014 mm, and 13.370 mm. The predicted results indicate that, to some extent, the dynamic model (LSTM) achieves results that are more accurate than those of the static models (i.e., SVR and BP). LSTM even

  9. The Bidimensional Impression Management Index (BIMI): measuring agentic and communal forms of impression management.

    Science.gov (United States)

    Blasberg, Sabrina A; Rogers, Katherine H; Paulhus, Delroy L

    2014-01-01

    Measures of impression management have yet to incorporate two-factor models of person perception. The 2 primary factors are often labeled agency and communion. In Study 1, we assembled a new measure of impression management—the Bidimensional Impression Management Index (BIMI): It comprises 2 subscales designed specifically to tap agentic and communal content. Both subscales showed adequate alpha reliabilities under both honest and faking conditions. In Study 2, the BIMI was cross-validated in a new sample: The subscales remained relatively independent, and their reliabilities remained solid. A coherent pattern of personality correlates also supported the validities of both subscales. In Study 3, the differential sensitivity of the 2 subscales was demonstrated by manipulating the job type in simulated job applications. Implications and applications of the BIMI are discussed.

  10. Distribución y corte de piezas irregulares con anidamiento bidimensional en la industria minera

    Directory of Open Access Journals (Sweden)

    José Arzola-Ruíz

    2010-03-01

    Full Text Available La necesidad del ahorro de material durante el corte de piezas en chapas ha provocado el desarrollo de procedimientos y técnicas de optimización, con la ayuda de las nuevas tecnologías de la informática y las comunicaciones. A pesar de la existencia de diversas plataformas automatizadas para la generación de distribuciones y rutas de corte, el ahorro de material constituye un indicador de permanente atención en la industria minera. En el presente trabajo se ilustra el estado actual del desarrollo de las técnicas de distribución y corte de piezas en chapas y se define la concepción de un procedimiento para la distribución de piezas irregulares con anidamiento bidimensional.

  11. Bidimensional characterization of the emission spectra in a direct current atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Orejas, Jaime; Pisonero, Jorge; Bordel, Nerea; Nelis, Thomas; Guillot, Philippe; Sanz-Medel, Alfredo

    2012-01-01

    An in-house atmospheric pressure glow discharge source, designed to be used as ionization/desorption source for ambient mass spectrometry, has been electrically characterized, and its optical emission spectra evaluated in detail. Electrical characterization showed that the plasma regime can vary from glow discharge to arc discharge depending on operating conditions (i.e. He flow rate and inter electrode distance). Furthermore, bidimensional images of the optical emission of some plasma species using filters as wavelength selectors, were registered from inside and outside the discharge chamber (inner region and afterglow region respectively), showing the spatial distribution of excited species (i.e. He*, N 2 + and O*). These distribution patterns are useful to study the chemistry of the discharge plasma, since different production pathways and different excitation energies affect the presence of these species in the plasma regions. - Highlights: ► An in-house APGD is characterized through electrical and OES measurements. ► Interelectrode distance had more effect on electric regime than He flow rate. ► Internal plume images showed differences on the production pathways for each species. ► Higher interelectrode distances and He flow rates showed better afterglow conditions.

  12. Bidimensional characterization of the emission spectra in a direct current atmospheric pressure glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Orejas, Jaime [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Pisonero, Jorge, E-mail: pisonerojorge@uniovi.es [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Bordel, Nerea [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Nelis, Thomas [Bern University of Applied Sciences, Quellgasse 21, 2501 Bienne (Switzerland); Guillot, Philippe [DPHE, CUFR J. F. Champollion, Universite de Toulouse, Place de Verdun, Albi (France); Sanz-Medel, Alfredo, E-mail: asm@uniovi.es [University of Oviedo, Department of Physical and Analytical Chemistry, C/ Julian Claveria 8, Oviedo (Spain)

    2012-10-15

    An in-house atmospheric pressure glow discharge source, designed to be used as ionization/desorption source for ambient mass spectrometry, has been electrically characterized, and its optical emission spectra evaluated in detail. Electrical characterization showed that the plasma regime can vary from glow discharge to arc discharge depending on operating conditions (i.e. He flow rate and inter electrode distance). Furthermore, bidimensional images of the optical emission of some plasma species using filters as wavelength selectors, were registered from inside and outside the discharge chamber (inner region and afterglow region respectively), showing the spatial distribution of excited species (i.e. He*, N{sub 2}{sup +} and O*). These distribution patterns are useful to study the chemistry of the discharge plasma, since different production pathways and different excitation energies affect the presence of these species in the plasma regions. - Highlights: Black-Right-Pointing-Pointer An in-house APGD is characterized through electrical and OES measurements. Black-Right-Pointing-Pointer Interelectrode distance had more effect on electric regime than He flow rate. Black-Right-Pointing-Pointer Internal plume images showed differences on the production pathways for each species. Black-Right-Pointing-Pointer Higher interelectrode distances and He flow rates showed better afterglow conditions.

  13. Locus of Control revisited: development of a new bi-dimensional measure

    Directory of Open Access Journals (Sweden)

    Javier Suárez-Álvarez

    Full Text Available Locus of control (LOC has a long tradition in Psychology, and various instruments have been designed for its measurement. However, the dimensionality of the construct is unclear, and still gives rise to considerable controversy. The aim of the present work is to present new evidence of validity in relation to the dimensionality of LOC. To this end, we developed a new measurement instrument with 23 items. The sample was made up of 697 Spanish participants, of whom 57.5% were women (M=22.43; SD= 9.19. The results support the bi-dimensionality of LOC: internal (α=.87 and external (α=.85. Furthermore, both subscales have shown adequate validity evidence in relation to self-efficacy, achievement motivation and optimism (r xy> .21. Statistically significant differences were found by sex (p < .05: men scored higher in external LOC and women in internal LOC. The validity evidence supports a two-dimensional structure for the LOC, and the measurement instrument developed showed adequate psychometric properties.

  14. Bi-dimensional arrays of SPAD for time-resolved single photon imaging

    International Nuclear Information System (INIS)

    Tudisco, S.; Lanzano, L.; Musumeci, F.; Neri, L.; Privitera, S.; Scordino, A.; Condorelli, G.; Fallica, G.; Mazzillo, M.; Sanfilippo, D.; Valvo, G.

    2009-01-01

    Many scientific areas like astronomy, biophysics, biomedicine, nuclear and plasma science, etc. are interested in the development of a new time-resolved single photon imaging device. Such a device represents today one of the most challenging goals in the field of photonics. In collaboration with Catania R and D staff of ST-Microelectronics (STM) we created, during the last few years, a new avalanche photosensor-Single Photon Avalanche Diode (SPAD) able to detect and count, with excellent performance, single photons. Further we will discuss the possible realization of a single photon imaging device through the many elements integration (bi-dimensional arrays) of SPADs. In order to achieve the goal, it is also important to develop an appropriate readout strategy able to address the time information of each individual sensor and in order to read a great number of elements easily. First prototypes were designed and manufactured by STM and the results are reported here. In the paper we will discuss in particular: (i) sensor performance (gain, photodetection efficiency, timing, after-pulsing, etc.); (ii) array performance (layout, cross-talk, etc.); (iii) readout strategy (quenching, electronics), and (iv) first imaging results (general performance).

  15. Trains of Red Blood Cells in a bi-dimensional microflows

    Science.gov (United States)

    Viallat, Annie; Iss, Cecile; Held, Delphine; Badens, Catherine; Charrier, Anne; Helfer, Emmanuèle; CINaM Team; Dpt de Génétique Médicale Team

    2017-11-01

    In the vascular microcirculation RBC distribution is uneven in the direction normal to the blood flow, as first evidenced by the existence of a cell-free layer near the vessel wall. In addition, the most rigid cells such as white blood cells and platelets are known to segregate to the walls while flowing in wide channels. We use microfluidic bi-dimensional channels (60 µm wide, 8 µm high, 5 mm long) to explore the flow structure in RBC suspensions at several hematocrits, flow rates and RBC rigidities. We observe the dynamical formation of RBC clusters and their motion along the flow direction. We study healthy RBCs, RBCs stiffened with glutaraldehyde, mixture of healthy and stiffened RBCs and RBC from sickle cell patients. Initially dispersed healthy RBCs organize, while flowing along the channel, into series of parallel trains. The train length depends on RBC hematocrit and flow rate. Stiffened RBCs do not cluster and mainly display tumbling motion like rigid disks. They destabilize existing trains and are preferentially observed close to the walls. We compared our results to that observed in microcapillaries, where trains of RBCs entirely fill in width the microchannel. This work has been carried out thanks to the support of the A*MIDEX project (n° ANR-11-IDEX-0001-02) funding by the ''Investissements d'Avenir'' French Government program, ma,ged by ANR.

  16. A Review and Empirical Comparison of Three Treatments for Adolescent Males with Conduct and Personality Disorder: Mode Deactivation Therapy, Cognitive Behavior Therapy and Social Skills Training

    Science.gov (United States)

    Apsche, Jack A.; Bass, Christopher K.

    2006-01-01

    This research study compared the efficacy of three treatment methodologies for adolescent males in residential treatment with conduct disorders and/or personality dysfunctions and documented problems with physical and sexual aggression. The results showed that Mode Deactivation Therapy, an advanced form of cognitive behavioral therapy based on…

  17. A Review and Empirical Comparison of Two Treatments for Adolescent Males with Conduct and Personality Disorder: Mode Deactivation Therapy and Cognitive Behavior Therapy

    Science.gov (United States)

    Apsche, Jack A.; Bass, Christopher K.; Jennings, Jerry L.; Siv, Alexander M.

    2005-01-01

    This research study compared the efficacy of two treatment methodologies for adolescent males in residential treatment with conduct disorders and/or personality dysfunctions and documented problems with physical and sexual aggression. The results showed that Mode Deactivation Therapy, an advanced form of cognitive behavioral therapy based on…

  18. Empirical Comparison of Three Treatments for Adolescent Males with Physical and Sexual Aggression: Mode Deactivation Therapy, Cognitive Behavior Therapy and Social Skills Training

    Science.gov (United States)

    Apsche, Jack A.; Bass, Christopher K.; Jennings, Jerry L.; Murphy, Christopher J.; Hunter, Linda A.; Siv, Alexander M.

    2005-01-01

    This research study compared the efficacy of three treatment methodologies for adolescent males in residential treatment with conduct disorders and/or personality dysfunctions and documented problems with physical and sexual aggression. The results showed that Mode Deactivation Therapy, an advanced form of cognitive behavioral therapy based on…

  19. Empirical study of travel mode forecasting improvement for the combined revealed preference/stated preference data–based discrete choice model

    Directory of Open Access Journals (Sweden)

    Yanfu Qiao

    2016-01-01

    Full Text Available The combined revealed preference/stated preference data–based discrete choice model has provided the actual choice-making restraints as well as reduced the prediction errors. But the random error variance of alternatives belonging to different data would impact its universality. In this article, we studied the traffic corridor between Chengdu and Longquan with the revealed preference/stated preference joint model, and the single stated preference data model separately predicted the choice probability of each mode. We found the revealed preference/stated preference joint model is universal only when there is a significant difference between the random error terms in different data. The single stated preference data would amplify the travelers’ preference and cause prediction error. We proposed a universal way that uses revealed preference data to modify the single stated preference data parameter estimation results to achieve the composite utility and reduce the prediction error. And the result suggests that prediction results are more reasonable based on the composite utility than the results based on the single stated preference data, especially forecasting the mode share of bus. The future metro line will be the main travel mode in this corridor, and 45% of passenger flow will transfer to the metro.

  20. The lottery-panel task for bi-dimensional parameter-free elicitation of risk attitudes

    Directory of Open Access Journals (Sweden)

    García-Gallego, Aurora

    2012-03-01

    Full Text Available In this paper, we propose a simple task for eliciting attitudes toward risky choice, the Sabater-Grande and Georgantzís (SGG lottery-panel task, which consists in a series of lotteries constructed to compensate riskier options with higher risk-return trade-offs. Using Principal Component Analysis technique, we show that the SGG lotterypanel task is capable of capturing two dimensions of individual risky decision making: subjects’ average willingness to choose risky projects and their sensitivity towards variations in the return to risk. We report results from a large dataset obtained from the implementation of the SGG lottery-panel task and discuss regularities and the desirability of its bi-dimensionality both for describing behaviour under uncertainty and explaining behaviour in other contexts.

    En este trabajo proponemos una tarea sencilla que permite obtener la actitud frente a la toma de riesgo monetario, y que llamaremos tarea Sabater-Grande y Georgantzís (SGG de riesgo. Esta tarea consiste en una serie de loterías construidas para compensar las opciones de mayor riesgo con un mayor retorno. Utilizando la técnica de componentes principales, encontramos que la tarea SGG es capaz de capturar dos dimensiones de la toma de decisiones individuales: por un lado, la voluntad promedio de los sujetos de elegir proyectos arriesgados y, por otro, su sensibilidad hacia las variaciones en el retorno por riesgo. Presentamos los resultados de una gran muestra de datos obtenidos a partir de la implementación de la tarea SGG, y discutimos las regularidades y la conveniencia de su bidimensionalidad tanto para describir el comportamiento en condiciones de incertidumbre como para explicar el comportamiento humano en otros contextos.

  1. Bi-dimensional null model analysis of presence-absence binary matrices.

    Science.gov (United States)

    Strona, Giovanni; Ulrich, Werner; Gotelli, Nicholas J

    2018-01-01

    Comparing the structure of presence/absence (i.e., binary) matrices with those of randomized counterparts is a common practice in ecology. However, differences in the randomization procedures (null models) can affect the results of the comparisons, leading matrix structural patterns to appear either "random" or not. Subjectivity in the choice of one particular null model over another makes it often advisable to compare the results obtained using several different approaches. Yet, available algorithms to randomize binary matrices differ substantially in respect to the constraints they impose on the discrepancy between observed and randomized row and column marginal totals, which complicates the interpretation of contrasting patterns. This calls for new strategies both to explore intermediate scenarios of restrictiveness in-between extreme constraint assumptions, and to properly synthesize the resulting information. Here we introduce a new modeling framework based on a flexible matrix randomization algorithm (named the "Tuning Peg" algorithm) that addresses both issues. The algorithm consists of a modified swap procedure in which the discrepancy between the row and column marginal totals of the target matrix and those of its randomized counterpart can be "tuned" in a continuous way by two parameters (controlling, respectively, row and column discrepancy). We show how combining the Tuning Peg with a wise random walk procedure makes it possible to explore the complete null space embraced by existing algorithms. This exploration allows researchers to visualize matrix structural patterns in an innovative bi-dimensional landscape of significance/effect size. We demonstrate the rational and potential of our approach with a set of simulated and real matrices, showing how the simultaneous investigation of a comprehensive and continuous portion of the null space can be extremely informative, and possibly key to resolving longstanding debates in the analysis of ecological

  2. Investigation of bone morphology using X-ray microfluorescence bidimensional mapping

    International Nuclear Information System (INIS)

    Lima, I.; Sales, E.; Anjos, M.J.; Assis, J.T.; Lopes, R.T.

    2008-01-01

    Full text: The utilization of radiation for medical purposes is an important tool that has been helping in finding the causes of several illnesses. In relation to application of radioisotope in medicine, it has been making a great contribution to the development of analytical techniques that can help diagnostic illness. The X-ray fluorescence technique is within this context providing identification of chemical elements, and moreover, it can provide its spatial concentrations and distributions in several kinds of biological tissues, such as bone. Several issues concerning bone metabolism are still under study, and the investigation of its morphology, in relation to mineral distribution, can be useful. The aim of this study is to characterize trabecular bone samples in order to verify the influence of the chemical elemental distribution in bone morphology through bi-dimensional mapping obtained through X-ray fluorescence technique with synchrotron radiation. The measurements were performed at Brazilian Synchrotron Light National Laboratory (XRF beam line). This line is equipped with an HPGe detector with a resolution of 150 eV at 5.9 keV, a white beam, and the sample holder is placed at 45 deg in relation to the detector and the incident beam. The beam is focused by a fine conical capillary which provides X-ray microbeam of 20 μm diameter. To perform the experiment, the samples were placed in a mylar adhesive tape, positioned in the experimental set up and their measurements was taken into account in the calculation of concentration. The spectra were acquired in 10 s and 200 s to perform 2D images and single profiles respectively. No sample preparation was required and the experiment was performed in vertebrae and femur bone sites (in several positions) with 150 μm of thickness approximately. It was measured NIST Standard Reference Material (bone ash and bone meal - SRM 1400 and SRM 1486) in order to evaluate our experimental method. The sample holder has complete

  3. Heuristica de dos-etapas para el problema de corte de piezas con guillotinado bidimensional

    Directory of Open Access Journals (Sweden)

    Juan Gabriel Correa Medina

    2014-08-01

    Full Text Available En un ambiente altamente competitivo, el problema de corte de guillotina bidimensional es un elemento clave en la reducción de costos. Este problema tiene una amplia gama de aplicaciones en industrias cuyos procesos de corte de materiales se realizan con máquinas que sólo permiten cortes de un extremo a otro. En este trabajo se presenta un algoritmo de dos etapas usando metaheurísticas para acomodar en una sola placa de ancho conocido y longitud infinita, un conjunto de ítems rectangulares fuertemente heterogéneos que pueden ser rotados 90°. El objetivo es minimizar la longitud requerida de la placa procurando la acumulación del desperdicio. En la primera etapa se aplica un algoritmo de búsqueda tabú para determinar el orden en que se acomodan los ítems. En la segunda, se busca determinar el mejor acomodo de los ítems en la placa mediante un algoritmo de recocido simulado. Se experimenta con un conjunto de instancias conocidas. Los resultados muestran que la rotación de piezas favorece la obtención de soluciones que igualan al menos las reportadas previamente en la literatura y que la concentración de los desperdicios incrementa su posibilidad de reutilización. Into a highly competitive environment, two-dimensional guillotine’s cut problem is an elementary key to cost reduction. This problem has a wide variety of applications into factories related to processes material cut. Cuts are done by machines which cut from one edge to other. A two stage algorithm is shown to place a finite set of items in a single plate with a known width and infinite length, using metaheuristics. All items are rectangular, mostly are distinct itself and each one can only be rotated 90 degrees at once. Main objective is minimization of length required by plate and waste accumulation were compacted as much as possible. First stage determines the order from items placed by using a tabu search algorithm. Second stage tries improving the order previous

  4. Gastronomía molecular: estudio de las condiciones de contorno de un modelo termomecánico bidimensional del suflé

    OpenAIRE

    Ruan Zhao, Víctor Siliang

    2018-01-01

    El presente Trabajo de Fin de Grado (TFG) tiene por objeto el estudio de condiciones de contorno realistas en un modelo bidimensional termomecánico del suflé. Continua el trabajo de dos trabajos anteriores [1] y [2] que realizaron un modelo unidimensional y bidimensional, respectivamente. Su realización se ha llevado a cabo en el laboratorio de Simulación de Materiales no Metálicos de la Escuela Técnica Superior de Ingenieros Industriales, centro de la Universidad Politécnica de Madrid (ET...

  5. The empirical research skills that English Majors under the mode of WebQuest%WebQuest模式下的英语专业学生听说技能实证探究

    Institute of Scientific and Technical Information of China (English)

    江凡

    2014-01-01

    WebQuest可以简单解释为网络调查探究,是一种可以利用网络资源进行研究学习的教学模式。WebQuest是一种发现式学习、自主式学习、合作式学习、探究式学习,使学生在这种环境中充分锻炼培养自己。WebQuest模式教学可以激发学生学习英语的兴趣,以此提高教学质量。该课题针对WebQuest模式下的英语英语专业学生听说技能实证进行了研究。%WebQuest can explore a simple explanation for the network investigation,is a study the teaching mode of learning through cyber source.WebQuest is a kind of discovery learning,autonomous learning, cooperative learning,inquiry learning,so that students in this environment to fully exercise training. WebQuest teaching model can stimulate students' interest in learning English,in order to improve the quality of teaching.The topic for the WebQuest mode of English major students listening and speaking skills empirical studied.

  6. Low-Pass Filtering Approach via Empirical Mode Decomposition Improves Short-Scale Entropy-Based Complexity Estimation of QT Interval Variability in Long QT Syndrome Type 1 Patients

    Directory of Open Access Journals (Sweden)

    Vlasta Bari

    2014-09-01

    Full Text Available Entropy-based complexity of cardiovascular variability at short time scales is largely dependent on the noise and/or action of neural circuits operating at high frequencies. This study proposes a technique for canceling fast variations from cardiovascular variability, thus limiting the effect of these overwhelming influences on entropy-based complexity. The low-pass filtering approach is based on the computation of the fastest intrinsic mode function via empirical mode decomposition (EMD and its subtraction from the original variability. Sample entropy was exploited to estimate complexity. The procedure was applied to heart period (HP and QT (interval from Q-wave onset to T-wave end variability derived from 24-hour Holter recordings in 14 non-mutation carriers (NMCs and 34 mutation carriers (MCs subdivided into 11 asymptomatic MCs (AMCs and 23 symptomatic MCs (SMCs. All individuals belonged to the same family developing long QT syndrome type 1 (LQT1 via KCNQ1-A341V mutation. We found that complexity indexes computed over EMD-filtered QT variability differentiated AMCs from NMCs and detected the effect of beta-blocker therapy, while complexity indexes calculated over EMD-filtered HP variability separated AMCs from SMCs. The EMD-based filtering method enhanced features of the cardiovascular control that otherwise would have remained hidden by the dominant presence of noise and/or fast physiological variations, thus improving classification in LQT1.

  7. Inglorious Empire

    DEFF Research Database (Denmark)

    Khair, Tabish

    2017-01-01

    Review of 'Inglorious Empire: What the British did to India' by Shashi Tharoor, London, Hurst Publishers, 2017, 296 pp., £20.00......Review of 'Inglorious Empire: What the British did to India' by Shashi Tharoor, London, Hurst Publishers, 2017, 296 pp., £20.00...

  8. The density of states for the Bi-dimensional Anderson model in the presence of a magnetic field with quantum plaque flux

    International Nuclear Information System (INIS)

    Kuehl, N.M.

    1987-01-01

    The regularity properties of the integrated density of states and the state density of the Anderson bidimensional tight-binding model, in the presence of a uniform magnetic field, perpendicular to the plane of the system by means of quantum flux with plaques, are studied. (A.C.A.S.) [pt

  9. Empirical likelihood

    CERN Document Server

    Owen, Art B

    2001-01-01

    Empirical likelihood provides inferences whose validity does not depend on specifying a parametric model for the data. Because it uses a likelihood, the method has certain inherent advantages over resampling methods: it uses the data to determine the shape of the confidence regions, and it makes it easy to combined data from multiple sources. It also facilitates incorporating side information, and it simplifies accounting for censored, truncated, or biased sampling.One of the first books published on the subject, Empirical Likelihood offers an in-depth treatment of this method for constructing confidence regions and testing hypotheses. The author applies empirical likelihood to a range of problems, from those as simple as setting a confidence region for a univariate mean under IID sampling, to problems defined through smooth functions of means, regression models, generalized linear models, estimating equations, or kernel smooths, and to sampling with non-identically distributed data. Abundant figures offer vi...

  10. Engine gearbox fault diagnosis using empirical mode ...

    Indian Academy of Sciences (India)

    Kiran Vernekar

    Department of Mechanical Engineering, National Institute of Technology Karnataka,. Surathkal ... proposed approach is an effective method for engine fault diagnosis. Keywords. Engine fault ... (DAQ) card and analysed using LabVIEW software from. Figure 1. .... and reduce numerical difficulties during the calculation. T.

  11. Quasi-bivariate variational mode decomposition as a tool of scale analysis in wall-bounded turbulence

    Science.gov (United States)

    Wang, Wenkang; Pan, Chong; Wang, Jinjun

    2018-01-01

    The identification and separation of multi-scale coherent structures is a critical task for the study of scale interaction in wall-bounded turbulence. Here, we propose a quasi-bivariate variational mode decomposition (QB-VMD) method to extract structures with various scales from instantaneous two-dimensional (2D) velocity field which has only one primary dimension. This method is developed from the one-dimensional VMD algorithm proposed by Dragomiretskiy and Zosso (IEEE Trans Signal Process 62:531-544, 2014) to cope with a quasi-2D scenario. It poses the feature of length-scale bandwidth constraint along the decomposed dimension, together with the central frequency re-balancing along the non-decomposed dimension. The feasibility of this method is tested on both a synthetic flow field and a turbulent boundary layer at moderate Reynolds number (Re_{τ } = 3458) measured by 2D particle image velocimetry (PIV). Some other popular scale separation tools, including pseudo-bi-dimensional empirical mode decomposition (PB-EMD), bi-dimensional EMD (B-EMD) and proper orthogonal decomposition (POD), are also tested for comparison. Among all these methods, QB-VMD shows advantages in both scale characterization and energy recovery. More importantly, the mode mixing problem, which degrades the performance of EMD-based methods, is avoided or minimized in QB-VMD. Finally, QB-VMD analysis of the wall-parallel plane in the log layer (at y/δ = 0.12) of the studied turbulent boundary layer shows the coexistence of large- or very large-scale motions (LSMs or VLSMs) and inner-scaled structures, which can be fully decomposed in both physical and spectral domains.

  12. Empirical Hamiltonians

    International Nuclear Information System (INIS)

    Peggs, S.; Talman, R.

    1987-01-01

    As proton accelerators get larger, and include more magnets, the conventional tracking programs which simulate them run slower. The purpose of this paper is to describe a method, still under development, in which element-by-element tracking around one turn is replaced by a single man, which can be processed far faster. It is assumed for this method that a conventional program exists which can perform faithful tracking in the lattice under study for some hundreds of turns, with all lattice parameters held constant. An empirical map is then generated by comparison with the tracking program. A procedure has been outlined for determining an empirical Hamiltonian, which can represent motion through many nonlinear kicks, by taking data from a conventional tracking program. Though derived by an approximate method this Hamiltonian is analytic in form and can be subjected to further analysis of varying degrees of mathematical rigor. Even though the empirical procedure has only been described in one transverse dimension, there is good reason to hope that it can be extended to include two transverse dimensions, so that it can become a more practical tool in realistic cases

  13. DIMCO. A new system for mechanical and bidimensional, of nuclear fuel pins; DIMCO un nuevo sistema de calculo mecanico de combustibles nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, A

    1977-07-01

    The system developed in JEN, for: the mechanical analysis uni and bidimensional, of nuclear fuels is presented. The mathematical and numerical foundations used, are here described. And so the models developed for effects such as swelling, cracking, clad growth etc. Numerical results for several cases are presented. a) Numerical test in one and two dimensions. b) Applicability range, c) Interaction effects. d) Influence of the power history. (Author) 17 refs.

  14. PROBLEMS WITH WIREDU'S EMPIRICALISM Martin Odei Ajei1 ...

    African Journals Online (AJOL)

    In his “Empiricalism: The Empirical Character of an African Philosophy”,. Kwasi Wiredu sets out ... others, that an empirical metaphysical system contains both empirical ..... realms which multiple categories of existents inhabit and conduct their being in .... to a mode of reasoning that conceives categories polarized by formal.

  15. 19 mm sized bileaflet valve prostheses' flow field investigated by bidimensional laser Doppler anemometry (part I: velocity profiles).

    Science.gov (United States)

    Barbaro, V; Grigioni, M; Daniele, C; D'Avenio, G; Boccanera, G

    1997-11-01

    The investigation of the flow field downstream of a cardiac valve prosthesis is a well established task. In particular turbulence generation is of interest if damage to blood constituents is to be assessed. Several prosthetic valve flow studies are available in literature but they generally concern large-sized prostheses. The FDA draft guidance requires the study of the maximum Reynolds number conditions for a cardiac valve model to assess the worst case in turbulence by choosing both the minimum valve diameter and a high cardiac output value as protocol set up. Within the framework of a national research project regarding the characterization of cardiovascular endoprostheses, the Laboratory of Biomedical Engineering is currently conducting an in-depth study of turbulence generated downstream of bileaflet cardiac valves. Four models of 19 mm sized bileaflet valve prostheses, namely St Jude Medical HP Edwards Tekna, Sorin Bicarbon, and CarboMedics, were studied in aortic position. The prostheses were selected for the nominal annulus diameter reported by the manufacturers without any assessment of the valve sizing method. The hemodynamic function was investigated using a bidimensional LDA system. Results concern velocity profiles during the peak flow systolic phase, at high cardiac output regime, highlighting the different flow field features downstream of the four small-sized cardiac valves.

  16. A bi-dimensional genome scan for prolificacy traits in pigs shows the existence of multiple epistatic QTL

    Directory of Open Access Journals (Sweden)

    Bidanel Jean P

    2009-12-01

    Full Text Available Abstract Background Prolificacy is the most important trait influencing the reproductive efficiency of pig production systems. The low heritability and sex-limited expression of prolificacy have hindered to some extent the improvement of this trait through artificial selection. Moreover, the relative contributions of additive, dominant and epistatic QTL to the genetic variance of pig prolificacy remain to be defined. In this work, we have undertaken this issue by performing one-dimensional and bi-dimensional genome scans for number of piglets born alive (NBA and total number of piglets born (TNB in a three generation Iberian by Meishan F2 intercross. Results The one-dimensional genome scan for NBA and TNB revealed the existence of two genome-wide highly significant QTL located on SSC13 (P SSC17 (P P P P P Conclusions The complex inheritance of prolificacy traits in pigs has been evidenced by identifying multiple additive (SSC13 and SSC17, dominant and epistatic QTL in an Iberian × Meishan F2 intercross. Our results demonstrate that a significant fraction of the phenotypic variance of swine prolificacy traits can be attributed to first-order gene-by-gene interactions emphasizing that the phenotypic effects of alleles might be strongly modulated by the genetic background where they segregate.

  17. Experimental characterization of a bi-dimensional array of negative capacitance piezo-patches for vibroacoustic control

    Science.gov (United States)

    Tateo, F.; Collet, M.; Ouisse, M.; Ichchou, M. N.; Cunefare, K. A.

    2013-04-01

    A recent technological revolution in the fields of integrated MEMS has finally rendered possible the mechanical integration of active smart materials, electronics and power supply systems for the next generation of smart composite structures. Using a bi-dimensional array of electromechanical transducers, composed by piezo-patches connected to a synthetic negative capacitance, it is possible to modify the dynamics of the underlying structure. In this study, we present an application of the Floquet-Bloch theorem for vibroacoustic power flow optimization, by means of distributed shunted piezoelectric material. In the context of periodically distributed damped 2D mechanical systems, this numerical approach allows one to compute the multi-modal waves dispersion curves into the entire first Brillouin zone. This approach also permits optimization of the piezoelectric shunting electrical impedance, which controls energy diffusion into the proposed semi-active distributed set of cells. Furthermore, we present experimental evidence that proves the effectiveness of the proposed control method. The experiment requires a rectangular metallic plate equipped with seventy-five piezo-patches, controlled independently by electronic circuits. More specifically, the out-of-plane displacements and the averaged kinetic energy of the controlled plate are compared in two different cases (open-circuit and controlled circuit). The resulting data clearly show how this proposed technique is able to damp and selectively reflect the incident waves.

  18. 19 mm sized bileaflet valve prostheses' flow field investigated by bidimensional laser Doppler anemometry (part II: maximum turbulent shear stresses)

    Science.gov (United States)

    Barbaro, V; Grigioni, M; Daniele, C; D'Avenio, G; Boccanera, G

    1997-11-01

    The investigation of the flow field generated by cardiac valve prostheses is a necessary task to gain knowledge on the possible relationship between turbulence-derived stresses and the hemolytic and thrombogenic complications in patients after valve replacement. The study of turbulence flows downstream of cardiac prostheses, in literature, especially concerns large-sized prostheses with a variable flow regime from very low up to 6 L/min. The Food and Drug Administration draft guidance requires the study of the minimum prosthetic size at a high cardiac output to reach the maximum Reynolds number conditions. Within the framework of a national research project regarding the characterization of cardiovascular endoprostheses, an in-depth study of turbulence generated downstream of bileaflet cardiac valves is currently under way at the Laboratory of Biomedical Engineering of the Istituto Superiore di Sanita. Four models of 19 mm bileaflet valve prostheses were used: St Jude Medical HP, Edwards Tekna, Sorin Bicarbon, and CarboMedics. The prostheses were selected for the nominal Tissue Annulus Diameter as reported by manufacturers without any assessment of valve sizing method, and were mounted in aortic position. The aortic geometry was scaled for 19 mm prostheses using angiographic data. The turbulence-derived shear stresses were investigated very close to the valve (0.35 D0), using a bidimensional Laser Doppler anemometry system and applying the Principal Stress Analysis. Results concern typical turbulence quantities during a 50 ms window at peak flow in the systolic phase. Conclusions are drawn regarding the turbulence associated to valve design features, as well as the possible damage to blood constituents.

  19. Empirical Hamiltonians

    International Nuclear Information System (INIS)

    Peggs, S.; Talman, R.

    1986-08-01

    As proton accelerators get larger, and include more magnets, the conventional tracking programs which simulate them run slower. At the same time, in order to more carefully optimize the higher cost of the accelerators, they must return more accurate results, even in the presence of a longer list of realistic effects, such as magnet errors and misalignments. For these reasons conventional tracking programs continue to be computationally bound, despite the continually increasing computing power available. This limitation is especially severe for a class of problems in which some lattice parameter is slowly varying, when a faithful description is only obtained by tracking for an exceedingly large number of turns. Examples are synchrotron oscillations in which the energy varies slowly with a period of, say, hundreds of turns, or magnet ripple or noise on a comparably slow time scale. In these cases one may with to track for hundreds of periods of the slowly varying parameter. The purpose of this paper is to describe a method, still under development, in which element-by-element tracking around one turn is replaced by a single map, which can be processed far faster. Similar programs have already been written in which successive elements are ''concatenated'' with truncation to linear, sextupole, or octupole order, et cetera, using Lie algebraic techniques to preserve symplecticity. The method described here is rather more empirical than this but, in principle, contains information to all orders and is able to handle resonances in a more straightforward fashion

  20. Bidimensional illustration touches in children books: consideration about their construction in the context of the education of children with visual impairments

    Directory of Open Access Journals (Sweden)

    Adriano Henrique Nuernberg

    2010-06-01

    Full Text Available The politics diffusion of the inclusive education last decade was positive for the several initiatives that wanted to promote the access to the knowledge from visual deficiency people. Many of these initiatives, however, have their theories from crooked notions about the ways of access and concepts elaborated of blind people, mainly when it deals with the congenital blindness. The goal of this article is to discuss the construction of bidimensional illustration touches as a way of guarantee the access of the visual content from children books. Based in the historic-cultural psychology from Vigotski, differences are pointed between the ways of visual and touch perception, taking the language as a way of blindness social compensation. Finding conceptual problems of the construction of these bidimensional illustration touches, it is a hope to collaborate for the improvement of the quality of the material produced in the context of the inclusive education, having in view the attention to the different topics of the psychical human being in the presence of the congenital blindness.

  1. Caracterización de las proteínas totales de tres ecotipos de maca (Lepidium peruvianum G. Chacón, mediante electroforesis unidimensional y bidimensional

    Directory of Open Access Journals (Sweden)

    Mario Monteghirfo

    2007-12-01

    Full Text Available Objetivo: Caracterizar las proteínas solubles que se encuentran en la raíz del Lepidium peruvianum G. Chacón, maca, mediante electroforesis unidimensional y electroforesis bidimensional. Diseño: Estudio de tipo observacional y transversal. Lugar: Centro de Investigación de Bioquímica y Nutrición Alberto Guzmán Barrón. Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Lima, Perú. Materiales: Raíces de Lepidium peruvianum G. Chacón ‘maca’ de los ecotipos blanco, amarillo y morado, procedentes de Junín que fueron obtenidas a través de la Universidad Nacional del Centro del Perú. Métodos: La extracción de las proteínas totales solubles se realizó con una solución antioxidante, seguida de electroforesis unidimensional y bidimensional para su caracterización. Principales medidas de resultados: Número de proteínas solubles, peso molecular de las proteínas y puntos isoelectricos de las proteínas más abundantes. Resultados: El análisis electroforético unidimensional mostró predominio de 2 proteínas (72% de las proteínas solubles totales. Una de 22,5 kDa, denominada en el presente trabajo ‘macatina’ (51% de la proteína total; la otra de 17,0 kDa (21% de la proteína soluble total. El mapa electroforético bidimensional mostró que tanto la ‘macatina’ como la proteína de 17,0 kDa son básicas y presentan 3 isómeros de carga que se distribuyen en un rango de punto isoeléctrico (pI de 7,1 a 8,2. Conclusiones: Las proteínas solubles mostraron un patrón electroforético complejo, siendo la macatina la proteína más abundante.

  2. Estimativa de peso ao nascimento utilizando a ultrassonografia bidimensional e tridimensional Estimate of birth weight using two- and three-dimensional ultrasonography

    Directory of Open Access Journals (Sweden)

    Luciano Marcondes Machado Nardozza

    2010-01-01

    Full Text Available OBJETIVO: Avaliar a acurácia de uma fórmula utilizando o volume do braço (VolBra, da coxa (VolCox e parâmetros bidimensionais [circunferência abdominal (CA e comprimento do fêmur (CF] fetais na predição de peso ao nascimento. MÉTODOS: Realizou-se um estudo do tipo corte transversal envolvendo 78 gestações únicas de fetos vivos, euploides e sem malformações estruturais, dentro de 48 horas antes do nascimento. O VolBra e o VolCox foram aferidos por meio da ultrassonografia tridimensional utilizando-se o modo multiplanar a intervalos de 5 mm. A CA e o CF foram aferidos por meio da ultrassonografia bidimensional. Foram realizadas análises de regressão linear e polinomial para determinação da melhor fórmula para predizer o peso fetal com base no VolBra, VolCox, CA e CF. Os erros obtidos com essas fórmulas foram comparados com os obtidos com as fórmulas de Shepard e Hadlock por meio de ANOVA. RESULTADOS: A melhor fórmula que estimou o peso ao nascimento foi uma linear simples (Peso= -1486,1 + 60,5CA + 140,57CF + 16,6VolBra + 4,8VolCox, com R2= 0,932. O erro (E, erro absoluto (EA, erro percentual (EP e erro percentual absoluto (EPA da fórmula que utiliza os parâmetros bi e tridimensionais foram 0 g, 0,2%, 112,2 g e 3,7%, respectivamente. Em relação às fórmulas bidimensionais, a nova equação apresentou menores E, EA, EP e EPA que a fórmula de Shepard, e menores EA e EPA em relação à fórmula de Hadlock. CONCLUSÃO: A fórmula de predição de peso utilizando o VolBra, VolCox, CF e CA se mostrou superior às fórmulas que utilizam apenas parâmetros bidimensionais.OBJECTIVE: Assess and compare accuracy of birth weight prediction using a combination of two-dimensional (abdominal circumference - AC and femur length - FL and three-dimensional parameters (fetal arm -VolArm and thigh -VolTh volumes. METHODS: A cross sectional study was carried out involving 78 singleton, live, euploid fetuses without structural malformations

  3. IMPLEMENTACIÓN DE UNA METODOLOGÍA PARA LA SEPARACIÓN DE PROTEOMAS DE PLASMA HUMANO MEDIANTE ELECTROFORESIS BIDIMENSIONAL

    Directory of Open Access Journals (Sweden)

    Ruth Andrea Rodríguez

    2015-09-01

    Full Text Available El análisis proteómico en derivados sanguíneos es una importante herramienta en el descubrimiento de biomarcadores para el diagnóstico de enfermedades, aunque su caracterización exhibe desafíos relacionados con el amplio rango dinámico de las proteínas. En este trabajo se implementaron las condiciones para la separación de proteomas de plasma sanguíneo por electroforesis bidimensional. En muestras de plasma de infante y adulto se evaluaron dos sistemas de pretratamiento de la muestra para reducir el rango dinámico de las proteínas: inmunodepleción de proteínas abundantes y enriquecimiento de proteínas de baja abundancia. Los proteomas se separaron por electroforesis bidimensional y las imágenes se analizaron con el programa Melanie 7.0. Se encontró que ambos métodos de pretratamiento fueron reproducibles y permitieron ver las diferencias en los proteomas de infante y adulto, como muestran los análisis de componentes principales y de clasificación jerárquica tipo heatmap. El porcentaje de recuperación de proteínas fue mayor con la inmunodepleción en comparación con el enriquecimiento proteico. Estos resultados permitieron concluir que con la inmunodepleción, se tiene mayor control de las proteínas eliminadas y por tanto menor pérdida de información, lo que permite su aplicación en estudios exploratorios para la identificación de potenciales biomarcadores de enfermedad.

  4. Empirical P-L-C relations for delta Scuti stars

    International Nuclear Information System (INIS)

    Gupta, S.K.

    1978-01-01

    Separate P-L-C relations have been empirically derived by sampling the delta Scuti stars according to their pulsation modes. The results based on these relations have been compared with those estimated from the model based P-L-C relations and the other existing empirical P-L-C relations. It is found that a separate P-L-C relation for each pulsation mode provides a better correspondence with observations. (Auth.)

  5. Empirical Test Case Specification

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Heiselberg, Per

    This document includes the empirical specification on the IEA task of evaluation building energy simulation computer programs for the Double Skin Facades (DSF) constructions. There are two approaches involved into this procedure, one is the comparative approach and another is the empirical one. I....... In the comparative approach the outcomes of different software tools are compared, while in the empirical approach the modelling results are compared with the results of experimental test cases....

  6. Plasma Modes

    Science.gov (United States)

    Dubin, D. H. E.

    This chapter explores several aspects of the linear electrostatic normal modes of oscillation for a single-species non-neutral plasma in a Penning trap. Linearized fluid equations of motion are developed, assuming the plasma is cold but collisionless, which allow derivation of the cold plasma dielectric tensor and the electrostatic wave equation. Upper hybrid and magnetized plasma waves in an infinite uniform plasma are described. The effect of the plasma surface in a bounded plasma system is considered, and the properties of surface plasma waves are characterized. The normal modes of a cylindrical plasma column are discussed, and finally, modes of spheroidal plasmas, and finite temperature effects on the modes, are briefly described.

  7. Study of dynamical properties in a bi-dimensional model describing the prey–predator dynamics with strong Allee effect in prey.

    Directory of Open Access Journals (Sweden)

    Partha Mandal

    2017-12-01

    Full Text Available In this work, we analyze a bi-dimensional differential equation system obtained by considering Holling type II functional response in prey–predator model with strong Allee effect in prey. One of the important consequence of this modification is the existence of separatrix curve which divides the behaviour of the trajectories in the phase plane. The results show that the origin is an attractor for any set of parameter values. Axial equilibrium points are stable or unstable according to the different parametric restrictions. The unique positive equilibrium point, if it exists, can be either an attractor or a repeller surrounded by a limit cycle, whose stability and uniqueness are also established. Therefore long-term coexistence of both populations is possible or they can go to extinction. Conditions on the parameter values are derived to show that the positive equilibrium point can be emerged or annihilated through transcritical bifurcation at axial equilibrium points. The existence of two heteroclinic curves is also established. It is also demonstrated that the origin is a global attractor in the phase plane for some parameter values, which implies that there are satisfying conditions where both populations can go to extinction. Ecological interpretations of all analytical results are provided thoroughly.

  8. Theoretical basis and significance of the variance of discharge as a bidimensional variable for the design of lateral lines of micro-irrigation Bases teóricas e importância da variância da vazão como variável bidimensional no dimensionamento de linhas laterais em microirrigação

    Directory of Open Access Journals (Sweden)

    Euro Roberto Detomini

    2009-08-01

    Full Text Available In order to support the theoretical basis and contribute to the improvement of educational capability issues relating to irrigation systems design, this point of view presents an alternative deduction of the variance of the discharge as a bidimensional and independent random variable. Then a subsequent brief application of an existing model is applied for statistical design of laterals in micro-irrigation. The better manufacturing precision of emitters allows lengthening a lateral for a given soil slope, although this does not necessarily mean that the statistical uniformity throughout the lateral will be more homogenous.Visando a reforçar as bases teóricas e contribuir com a melhoria da capacitação educacional em assuntos relacionados a dimensionamento de sistemas de irrigação, o presente ponto de vista revela uma dedução alternativa para a variância da vazão dos emissores, variável aleatória independente bidimensional. Posteriormente apresenta breve aplicação do modelo aceito para dimensionamento de linhas laterais em sistemas de microirrigação, de acordo com a abordagem estatística. A melhor precisão na fabricação de emssores permite, para uma dada inclinação de terreno, dimensionar laterais mais longas, o que não significa necessariamente que uniformidade de emissão dessas laterais será projetada como mais homogênea.

  9. Empirical Philosophy of Science

    DEFF Research Database (Denmark)

    Mansnerus, Erika; Wagenknecht, Susann

    2015-01-01

    knowledge takes place through the integration of the empirical or historical research into the philosophical studies, as Chang, Nersessian, Thagard and Schickore argue in their work. Building upon their contributions we will develop a blueprint for an Empirical Philosophy of Science that draws upon...... qualitative methods from the social sciences in order to advance our philosophical understanding of science in practice. We will regard the relationship between philosophical conceptualization and empirical data as an iterative dialogue between theory and data, which is guided by a particular ‘feeling with......Empirical insights are proven fruitful for the advancement of Philosophy of Science, but the integration of philosophical concepts and empirical data poses considerable methodological challenges. Debates in Integrated History and Philosophy of Science suggest that the advancement of philosophical...

  10. Tacoma mode

    International Nuclear Information System (INIS)

    Courant, E.D.; Ruth, R.D.; Wang, J.M.

    1979-01-01

    The name Tacoma refers to the Tacoma Narrows Bridge which collapsed on November 8, 1940 due to massive oscillations caused by high winds. One of the destructive modes was a torsion mode which was excited by transverse wind, a dipole force, and continued until the bridge collapsed. The name is used to refer to a coherent mode of oscillation of a spectrum of oscillators in which the amplitude vs frequency graph contains one node, where the node occurs near the driving frequency and a ω is not symmetric about zero. When this result is applied to vertical instabilities in coasting beams, it implies the existence of a coherent skew quadrupole moment, Q/sub xy/, whenever a coherent dipole oscillation exists

  11. Tacoma mode

    International Nuclear Information System (INIS)

    Courant, E.D.; Ruth, R.D.; Wang, J.M.

    1979-01-01

    The name Tacoma refers to the Tacoma Narrows Bridge which collapsed on November 8, 1940 due to massive oscillations caused by high winds. One of the destructive modes was a torsion mode which was excited by transverse wind, a dipole force, and continued until the bridge collapsed. The name is used to refer to a coherent mode of oscillation of a spectrum of oscillators in which the amplitude vs frequency graph contains one node, where the node occurs near the driving frequency and a(ω) is not symmetric about zero. When this result is applied to vertical instabilities in coasting beams, it implies the existence of a coherent skew quadrupole moment, whenever a coherent dipole oscillation exists

  12. anisotropic crack modelling of reinforced concrete structures with an enhanced kinematics: application to bidimensional elements under cyclic loading

    International Nuclear Information System (INIS)

    Kishta, Ejona

    2016-01-01

    Civil engineering buildings, massive and unique, are mostly made of reinforced or prestressed concrete. Sustainability, tightness and safety are the major pillars of a building's performance. Cracking is a major phenomenon which impacts the buildings' behaviour under different loadings in terms of sustainability and structural capacity. Development of numerical models which describe accurately the response of quasi-brittle materials under complex loading remains an important research topic for the scientific community. The objective of this work is the development of a numerical model which represents explicitly cracking of reinforced concrete structures. Concrete and reinforced concrete degradation process, characterised by the appearance of several anisotropic crack families, is described by means of an anisotropic damage model accounting for oriented crack families. The kinematics of this model is enriched with a displacement jump in order to reproduce the development of cracks in the material during loading. This displacement jump is identified as the crack opening. The developed model is validated on simulations of plain concrete structures exhibiting model as well as mixed-mode failure. The performances of the enriched model are shown by the simulation of reinforced concrete structures such as a shear wall submitted to cyclic loading. (author) [fr

  13. Failure Modes

    DEFF Research Database (Denmark)

    Jakobsen, K. P.; Burcharth, H. F.; Ibsen, Lars Bo

    1999-01-01

    The present appendix contains the derivation of ten different limit state equations divided on three different failure modes. Five of the limit state equations can be used independently of the characteristics of the subsoil, whereas the remaining five can be used for either drained or undrained s...

  14. Life Writing After Empire

    DEFF Research Database (Denmark)

    A watershed moment of the twentieth century, the end of empire saw upheavals to global power structures and national identities. However, decolonisation profoundly affected individual subjectivities too. Life Writing After Empire examines how people around the globe have made sense of the post...... in order to understand how individual life writing reflects broader societal changes. From far-flung corners of the former British Empire, people have turned to life writing to manage painful or nostalgic memories, as well as to think about the past and future of the nation anew through the personal...

  15. Theological reflections on empire

    Directory of Open Access Journals (Sweden)

    Allan A. Boesak

    2009-11-01

    Full Text Available Since the meeting of the World Alliance of Reformed Churches in Accra, Ghana (2004, and the adoption of the Accra Declaration, a debate has been raging in the churches about globalisation, socio-economic justice, ecological responsibility, political and cultural domination and globalised war. Central to this debate is the concept of empire and the way the United States is increasingly becoming its embodiment. Is the United States a global empire? This article argues that the United States has indeed become the expression of a modern empire and that this reality has considerable consequences, not just for global economics and politics but for theological refl ection as well.

  16. Empirical Evidence from Kenya

    African Journals Online (AJOL)

    FIRST LADY

    2011-01-18

    Jan 18, 2011 ... Empirical results reveal that consumption of sugar in. Kenya varies ... experiences in trade in different regions of the world. Some studies ... To assess the relationship between domestic sugar retail prices and sugar sales in ...

  17. Lie algebraic approach to the time-dependent quantum general harmonic oscillator and the bi-dimensional charged particle in time-dependent electromagnetic fields

    International Nuclear Information System (INIS)

    Ibarra-Sierra, V.G.; Sandoval-Santana, J.C.; Cardoso, J.L.; Kunold, A.

    2015-01-01

    We discuss the one-dimensional, time-dependent general quadratic Hamiltonian and the bi-dimensional charged particle in time-dependent electromagnetic fields through the Lie algebraic approach. Such method consists in finding a set of generators that form a closed Lie algebra in terms of which it is possible to express a quantum Hamiltonian and therefore the evolution operator. The evolution operator is then the starting point to obtain the propagator as well as the explicit form of the Heisenberg picture position and momentum operators. First, the set of generators forming a closed Lie algebra is identified for the general quadratic Hamiltonian. This algebra is later extended to study the Hamiltonian of a charged particle in electromagnetic fields exploiting the similarities between the terms of these two Hamiltonians. These results are applied to the solution of five different examples: the linear potential which is used to introduce the Lie algebraic method, a radio frequency ion trap, a Kanai–Caldirola-like forced harmonic oscillator, a charged particle in a time dependent magnetic field, and a charged particle in constant magnetic field and oscillating electric field. In particular we present exact analytical expressions that are fitting for the study of a rotating quadrupole field ion trap and magneto-transport in two-dimensional semiconductor heterostructures illuminated by microwave radiation. In these examples we show that this powerful method is suitable to treat quadratic Hamiltonians with time dependent coefficients quite efficiently yielding closed analytical expressions for the propagator and the Heisenberg picture position and momentum operators. -- Highlights: •We deal with the general quadratic Hamiltonian and a particle in electromagnetic fields. •The evolution operator is worked out through the Lie algebraic approach. •We also obtain the propagator and Heisenberg picture position and momentum operators. •Analytical expressions for a

  18. Lie algebraic approach to the time-dependent quantum general harmonic oscillator and the bi-dimensional charged particle in time-dependent electromagnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Ibarra-Sierra, V.G.; Sandoval-Santana, J.C. [Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 México D.F. (Mexico); Cardoso, J.L. [Área de Física Teórica y Materia Condensada, Universidad Autónoma Metropolitana Azcapotzalco, Av. San Pablo 180, Col. Reynosa-Tamaulipas, Azcapotzalco, 02200 México D.F. (Mexico); Kunold, A., E-mail: akb@correo.azc.uam.mx [Área de Física Teórica y Materia Condensada, Universidad Autónoma Metropolitana Azcapotzalco, Av. San Pablo 180, Col. Reynosa-Tamaulipas, Azcapotzalco, 02200 México D.F. (Mexico)

    2015-11-15

    We discuss the one-dimensional, time-dependent general quadratic Hamiltonian and the bi-dimensional charged particle in time-dependent electromagnetic fields through the Lie algebraic approach. Such method consists in finding a set of generators that form a closed Lie algebra in terms of which it is possible to express a quantum Hamiltonian and therefore the evolution operator. The evolution operator is then the starting point to obtain the propagator as well as the explicit form of the Heisenberg picture position and momentum operators. First, the set of generators forming a closed Lie algebra is identified for the general quadratic Hamiltonian. This algebra is later extended to study the Hamiltonian of a charged particle in electromagnetic fields exploiting the similarities between the terms of these two Hamiltonians. These results are applied to the solution of five different examples: the linear potential which is used to introduce the Lie algebraic method, a radio frequency ion trap, a Kanai–Caldirola-like forced harmonic oscillator, a charged particle in a time dependent magnetic field, and a charged particle in constant magnetic field and oscillating electric field. In particular we present exact analytical expressions that are fitting for the study of a rotating quadrupole field ion trap and magneto-transport in two-dimensional semiconductor heterostructures illuminated by microwave radiation. In these examples we show that this powerful method is suitable to treat quadratic Hamiltonians with time dependent coefficients quite efficiently yielding closed analytical expressions for the propagator and the Heisenberg picture position and momentum operators. -- Highlights: •We deal with the general quadratic Hamiltonian and a particle in electromagnetic fields. •The evolution operator is worked out through the Lie algebraic approach. •We also obtain the propagator and Heisenberg picture position and momentum operators. •Analytical expressions for a

  19. Enquistación in vitro de Giardia lamblia: análisis por electroforesis bidimensional de proteínas expresadas diferencialmente.

    Directory of Open Access Journals (Sweden)

    Paula C. Hernández

    2002-09-01

    Full Text Available La reconstrucción in vitro del ciclo de vida de Giardia lamblia es un excelente instrumento para el estudio de la biología molecular del parásito. El presente trabajo pretende contribuir al desarrollo de algunas técnicas por las cuales se puede definir mejor un modelo de diferenciación celular del parásito. El estudio presenta un protocolo de enquistación in vitro y establece un método para el aislamiento y la purificación de los quistes producidos, cuyas características morfológicas, por microscopía de luz, coinciden con las de los quistes obtenidos in vivo. Se estudió el mapa de las proteínas de G. lamblia por medio de electroforesis bidimensional de alta resolución y de electroforesis en una dimensión. Estos estudios mostraron que la mayoría de las proteínas del parásito son de carácter ácido. Se amplió, con base en ese resultado, la resolución de la región ácida por medio de un isoelectroenfoque de pH 4-7 en la primera dimensión. Se encontraron diferencias en la expresión de las proteínas durante el proceso de enquistación. Se obtuvieron, además, imágenes por microscopía de luz y electrónica de transmisión que permitieron observar morfológica y ultraestructuralmente las células producidas durante el proceso de la enquistación.

  20. Exploring intra- and inter-reader variability in uni-dimensional, bi-dimensional, and volumetric measurements of solid tumors on CT scans reconstructed at different slice intervals

    International Nuclear Information System (INIS)

    Zhao, Binsheng; Tan, Yongqiang; Bell, Daniel J.; Marley, Sarah E.; Guo, Pingzhen; Mann, Helen; Scott, Marietta L.J.; Schwartz, Lawrence H.; Ghiorghiu, Dana C.

    2013-01-01

    Objective: Understanding magnitudes of variability when measuring tumor size may be valuable in improving detection of tumor change and thus evaluating tumor response to therapy in clinical trials and care. Our study explored intra- and inter-reader variability of tumor uni-dimensional (1D), bi-dimensional (2D), and volumetric (VOL) measurements using manual and computer-aided methods (CAM) on CT scans reconstructed at different slice intervals. Materials and methods: Raw CT data from 30 patients enrolled in oncology clinical trials was reconstructed at 5, 2.5, and 1.25 mm slice intervals. 118 lesions in the lungs, liver, and lymph nodes were analyzed. For each lesion, two independent radiologists manually and, separately, using computer software, measured the maximum diameter (1D), maximum perpendicular diameter, and volume (CAM only). One of them blindly repeated the measurements. Intra- and inter-reader variability for the manual method and CAM were analyzed using linear mixed-effects models and Bland–Altman method. Results: For the three slice intervals, the maximum coefficients of variation for manual intra-/inter-reader variability were 6.9%/9.0% (1D) and 12.3%/18.0% (2D), and for CAM were 5.4%/9.3% (1D), 11.3%/18.8% (2D) and 9.3%/18.0% (VOL). Maximal 95% reference ranges for the percentage difference in intra-reader measurements for manual 1D and 2D, and CAM VOL were (−15.5%, 25.8%), (−27.1%, 51.6%), and (−22.3%, 33.6%), respectively. Conclusions: Variability in measuring the diameter and volume of solid tumors, manually and by CAM, is affected by CT slice interval. The 2.5 mm slice interval provides the least measurement variability. Among the three techniques, 2D has the greatest measurement variability compared to 1D and 3D

  1. Scaling law to determine peak forces in tapping-mode AFM experiments on finite elastic soft matter systems.

    Science.gov (United States)

    Guzman, Horacio V

    2017-01-01

    Analytical equations to estimate the peak force will facilitate the interpretation and the planning of amplitude-modulation force microscopy (tapping mode) experiments. A closed-form analytical equation to estimate the tip-sample peak forces while imaging soft materials in liquid environment and within an elastic deformation regime has been deduced. We have combined a multivariate regression method with input from the virial-dissipation equations and Tatara's bidimensional deformation contact mechanics model. The equation enables to estimate the peak force based on the tapping mode observables, probe characteristics and the material properties of the sample. The accuracy of the equation has been verified by comparing it to numerical simulations for the archetypical operating conditions to image soft matter with high spatial resolution in tapping-mode AFM.

  2. Spin modes

    International Nuclear Information System (INIS)

    Gaarde, C.

    1985-01-01

    An analysis of spectra of (p,n) reactions showed that they were very selective in exciting spin modes. Charge exchange reactions at intermediate energies give important new understanding of the M1-type of excitations and of the spin structure of continuum p spectra in general. In this paper, the author discusses three charge exchange reactions: (p,n); ( 3 H,t); and (d,2p) at several targets. Low-lying states and the Δ region are discussed separately. Finally, the charge exchange reaction with heavy ion beams is briefly discussed. (G.J.P./Auth.)

  3. Empirical philosophy of science

    DEFF Research Database (Denmark)

    Wagenknecht, Susann; Nersessian, Nancy J.; Andersen, Hanne

    2015-01-01

    A growing number of philosophers of science make use of qualitative empirical data, a development that may reconfigure the relations between philosophy and sociology of science and that is reminiscent of efforts to integrate history and philosophy of science. Therefore, the first part...... of this introduction to the volume Empirical Philosophy of Science outlines the history of relations between philosophy and sociology of science on the one hand, and philosophy and history of science on the other. The second part of this introduction offers an overview of the papers in the volume, each of which...... is giving its own answer to questions such as: Why does the use of qualitative empirical methods benefit philosophical accounts of science? And how should these methods be used by the philosopher?...

  4. Microtearing modes

    International Nuclear Information System (INIS)

    Garbet, X.; Mourgues, F.; Samain, A.; Zou, X.

    1990-01-01

    A serious degradation of confinement with additional heating is commonly observed on most tokamaks. The microtearing modes could provide an explanation for this experimental fact. They are driven linearly unstable by diamagnetism in collisional regimes, but it may be shown that the collisions in non linear regimes provide a small diffusion coefficient which can be only significant at the plasme edge. In the bulk of the plasma, the microtearing turbulence could play a basic role if it is unstable in the collisionless regime. While it is linearly stable without collisions, it could be driven unstable in realistic regimes by the radial diffusion it induces. To study this effect, we have used a model where the non linear action of the modes on a given helicity component is represented by a diffusion operator. They are found unstable for reasonable β p =2μ o nT/B 2 p , with a special radial profile of the potential vector A. The problem arises the validity of this model where non linearities in the trajectories behaviour are replaced by the diffusion which broadens resonances. To test this procedure, we calculate the actual electron distribution function when it is determined by the ergodicity of the field lines. We compute the correlations of the distribution function with the magnetic perturbation and compare them with the analytical expressions derived from the resonance broadening model. (author) 3 refs., 2 figs

  5. Empire vs. Federation

    DEFF Research Database (Denmark)

    Gravier, Magali

    2011-01-01

    The article discusses the concepts of federation and empire in the context of the European Union (EU). Even if these two concepts are not usually contrasted to one another, the article shows that they refer to related type of polities. Furthermore, they can be used at a time because they shed light...... on different and complementary aspects of the European integration process. The article concludes that the EU is at the crossroads between federation and empire and may remain an ‘imperial federation’ for several decades. This could mean that the EU is on the verge of transforming itself to another type...

  6. Empirical comparison of theories

    International Nuclear Information System (INIS)

    Opp, K.D.; Wippler, R.

    1990-01-01

    The book represents the first, comprehensive attempt to take an empirical approach for comparative assessment of theories in sociology. The aims, problems, and advantages of the empirical approach are discussed in detail, and the three theories selected for the purpose of this work are explained. Their comparative assessment is performed within the framework of several research projects, which among other subjects also investigate the social aspects of the protest against nuclear power plants. The theories analysed in this context are the theory of mental incongruities and that of the benefit, and their efficiency in explaining protest behaviour is compared. (orig./HSCH) [de

  7. Empirical Music Aesthetics

    DEFF Research Database (Denmark)

    Grund, Cynthia M.

    The toolbox for empirically exploring the ways that artistic endeavors convey and activate meaning on the part of performers and audiences continues to expand. Current work employing methods at the intersection of performance studies, philosophy, motion capture and neuroscience to better understand...... musical performance and reception is inspired by traditional approaches within aesthetics, but it also challenges some of the presuppositions inherent in them. As an example of such work I present a research project in empirical music aesthetics begun last year and of which I am a team member....

  8. Hidrodinámica bidimensional del canal de descarga de la central hidroeléctrica de Caruachi: correlación modelo matemático 2DH-Prototipo

    OpenAIRE

    Toscano Díaz, M.A.; Montilla Castro, G.A.

    2007-01-01

    La Central Hidroeléctrica de Caruachi está localizada en la zona Sur-Oriental de Venezuela en el Estado Bolívar sobre las aguas del río Caroní. Está equipada por 12 turbinas tipo Kaplan con 2196 MW de potencia instalada y un Aliviadero con una capacidad de 30000 m3/s. En este trabajo se presenta una correlación Modelo Matemático – Prototipo, cuyo objetivo es determinar la hidrodinámica del flujo del Canal de Descarga de Caruachi mediante el modelo matemático bidimensional SMS-FESWMS-2DH. El m...

  9. The evolution of transmission mode

    Science.gov (United States)

    Forbes, Mark R.; Hauffe, Heidi C.; Kallio, Eva R.; Okamura, Beth; Sait, Steven M.

    2017-01-01

    This article reviews research on the evolutionary mechanisms leading to different transmission modes. Such modes are often under genetic control of the host or the pathogen, and often in conflict with each other via trade-offs. Transmission modes may vary among pathogen strains and among host populations. Evolutionary changes in transmission mode have been inferred through experimental and phylogenetic studies, including changes in transmission associated with host shifts and with evolution of the unusually complex life cycles of many parasites. Understanding the forces that determine the evolution of particular transmission modes presents a fascinating medley of problems for which there is a lack of good data and often a lack of conceptual understanding or appropriate methodologies. Our best information comes from studies that have been focused on the vertical versus horizontal transmission dichotomy. With other kinds of transitions, theoretical approaches combining epidemiology and population genetics are providing guidelines for determining when and how rapidly new transmission modes may evolve, but these are still in need of empirical investigation and application to particular cases. Obtaining such knowledge is a matter of urgency in relation to extant disease threats. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’. PMID:28289251

  10. Biophysical and biological contributions of polyamine-coated carbon nanotubes and bidimensional buckypapers in the delivery of miRNAs to human cells

    Directory of Open Access Journals (Sweden)

    Celluzzi A

    2017-12-01

    transfection efficiency of a rigid scaffold. In conclusion, we extensively investigated the biophysical and biological contributions of polyamine-coated CNTs and bidimensional BPs in the delivery of miRNAs to human cells, in order to optimize the transfection efficiency of these compounds to be employed as efficient drug delivery vectors in biomedical applications. Keywords: carbon nanotubes, buckypapers, polyamines, cytotoxicity, cell transfection 

  11. Los recursos tecnológicos en la estadística bidimensional en los textos españoles de bachillerato

    Directory of Open Access Journals (Sweden)

    María M. Gea

    2015-12-01

    Full Text Available Los currículos actuales recomiendan el uso de los recursos tecnológicos en la enseñanza de la estadística, por la ventaja que suponen en el cálculo y representación gráfica, el trabajo con datos reales y el aprendizaje de conceptos a través de la simulación. En esta investigación se analizan los recursos tecnológicos que los libros de texto sugieren para la enseñanza y aprendizaje de la estadística bidimensional en bachillerato (organización y representación de datos bidimensionales, correlación y regresión. La importancia de este aspecto se debe a que extiende la dependencia funcional a situaciones aleatorias y proporciona al alumno oportunidades de modelizar numerosas aplicaciones. Por otro lado, la investigación didáctica muestra dificultades de comprensión y concepciones erróneas en esta área. Mediante un análisis de contenido se han estudiado dieciséis libros de texto españoles, ocho libros de cada una de las dos especialidades de bachillerato que incluyen “Humanidades y Ciencias Sociales” y “Ciencia y Tecnología”. En dichos libros se estudia el uso que se hace de recursos tecnológicos en los problemas y procedimientos propuestos, los tipos de recursos que se referencian para trabajar con internet y el contenido de un CD que acompaña a la mayoría de estos textos. Los resultados muestran una escasa presencia de recursos tecnológicos en los textos analizados, a la vez que una gran variabilidad de los recursos descritos. La referencia a recursos en internet se suele restringir a unidades didácticas y no a conjuntos de datos que puedan usarse en proyectos o a simuladores que faciliten la comprensión conceptual. El CD que acompaña a los textos a veces reproduce el mismo texto o se reduce a colecciones de ejercicios tradicionales; son minoría los problemas y procedimientos que usan recursos tecnológicos. Se concluye con algunas recomendaciones para la mejora de estos textos, teniendo en cuenta dichos

  12. Empirical research through design

    NARCIS (Netherlands)

    Keyson, D.V.; Bruns, M.

    2009-01-01

    This paper describes the empirical research through design method (ERDM), which differs from current approaches to research through design by enforcing the need for the designer, after a series of pilot prototype based studies, to a-priori develop a number of testable interaction design hypothesis

  13. Essays in empirical microeconomics

    NARCIS (Netherlands)

    Péter, A.N.

    2016-01-01

    The empirical studies in this thesis investigate various factors that could affect individuals' labor market, family formation and educational outcomes. Chapter 2 focuses on scheduling as a potential determinant of individuals' productivity. Chapter 3 looks at the role of a family factor on

  14. Worship, Reflection, Empirical Research

    OpenAIRE

    Ding Dong,

    2012-01-01

    In my youth, I was a worshipper of Mao Zedong. From the latter stage of the Mao Era to the early years of Reform and Opening, I began to reflect on Mao and the Communist Revolution he launched. In recent years I’ve devoted myself to empirical historical research on Mao, seeking the truth about Mao and China’s modern history.

  15. Trade and Empire

    DEFF Research Database (Denmark)

    Bang, Peter Fibiger

    2007-01-01

    This articles seeks to establish a new set of organizing concepts for the analysis of the Roman imperial economy from Republic to late antiquity: tributary empire, port-folio capitalism and protection costs. Together these concepts explain better economic developments in the Roman world than the...

  16. Empirically sampling Universal Dependencies

    DEFF Research Database (Denmark)

    Schluter, Natalie; Agic, Zeljko

    2017-01-01

    Universal Dependencies incur a high cost in computation for unbiased system development. We propose a 100% empirically chosen small subset of UD languages for efficient parsing system development. The technique used is based on measurements of model capacity globally. We show that the diversity o...

  17. OBSERVATIONS OF SAUSAGE MODES IN MAGNETIC PORES

    International Nuclear Information System (INIS)

    Morton, R. J.; Erdelyi, R.; Jess, D. B.; Mathioudakis, M.

    2011-01-01

    We present here evidence for the observation of the magnetohydrodynamic (MHD) sausage modes in magnetic pores in the solar photosphere. Further evidence for the omnipresent nature of acoustic global modes is also found. The empirical decomposition method of wave analysis is used to identify the oscillations detected through a 4170 A 'blue continuum' filter observed with the Rapid Oscillations in the Solar Atmosphere (ROSA) instrument. Out of phase, periodic behavior in pore size and intensity is used as an indicator of the presence of magnetoacoustic sausage oscillations. Multiple signatures of the magnetoacoustic sausage mode are found in a number of pores. The periods range from as short as 30 s up to 450 s. A number of the magnetoacoustic sausage mode oscillations found have periods of 3 and 5 minutes, similar to the acoustic global modes of the solar interior. It is proposed that these global oscillations could be the driver of the sausage-type magnetoacoustic MHD wave modes in pores.

  18. Adjuvanted vaccines: Aspects of immunosafety and modes of action

    NARCIS (Netherlands)

    Aalst, Susan van

    2017-01-01

    New developments in vaccine design shift towards safe, though sometimes less immunogenic, subunit and synthetic antigens. Therefore, the majority of current vaccines require adjuvants to increase immunogenicity. Most adjuvants available were developed empirically and their mode of action is only

  19. Autobiography After Empire

    DEFF Research Database (Denmark)

    Rasch, Astrid

    of the collective, but insufficient attention has been paid to how individuals respond to such narrative changes. This dissertation examines the relationship between individual and collective memory at the end of empire through analysis of 13 end of empire autobiographies by public intellectuals from Australia......Decolonisation was a major event of the twentieth century, redrawing maps and impacting on identity narratives around the globe. As new nations defined their place in the world, the national and imperial past was retold in new cultural memories. These developments have been studied at the level......, the Anglophone Caribbean and Zimbabwe. I conceive of memory as reconstructive and social, with individual memory striving to make sense of the past in the present in dialogue with surrounding narratives. By examining recurring tropes in the autobiographies, like colonial education, journeys to the imperial...

  20. Gazprom: the new empire

    International Nuclear Information System (INIS)

    Guillemoles, A.; Lazareva, A.

    2008-01-01

    Gazprom is conquering the world. The Russian industrial giant owns the hugest gas reserves and enjoys the privilege of a considerable power. Gazprom edits journals, owns hospitals, airplanes and has even built cities where most of the habitants work for him. With 400000 workers, Gazprom represents 8% of Russia's GDP. This inquiry describes the history and operation of this empire and show how its has become a masterpiece of the government's strategy of russian influence reconquest at the world scale. Is it going to be a winning game? Are the corruption affairs and the expected depletion of resources going to weaken the empire? The authors shade light on the political and diplomatic strategies that are played around the crucial dossier of the energy supply. (J.S.)

  1. Boundary methods for mode estimation

    Science.gov (United States)

    Pierson, William E., Jr.; Ulug, Batuhan; Ahalt, Stanley C.

    1999-08-01

    This paper investigates the use of Boundary Methods (BMs), a collection of tools used for distribution analysis, as a method for estimating the number of modes associated with a given data set. Model order information of this type is required by several pattern recognition applications. The BM technique provides a novel approach to this parameter estimation problem and is comparable in terms of both accuracy and computations to other popular mode estimation techniques currently found in the literature and automatic target recognition applications. This paper explains the methodology used in the BM approach to mode estimation. Also, this paper quickly reviews other common mode estimation techniques and describes the empirical investigation used to explore the relationship of the BM technique to other mode estimation techniques. Specifically, the accuracy and computational efficiency of the BM technique are compared quantitatively to the a mixture of Gaussian (MOG) approach and a k-means approach to model order estimation. The stopping criteria of the MOG and k-means techniques is the Akaike Information Criteria (AIC).

  2. Audit mode change, corporate governance

    Directory of Open Access Journals (Sweden)

    Limei Cao

    2015-12-01

    Full Text Available This study investigates changes in audit strategy in China following the introduction of risk-based auditing standards rather than an internal control-based audit mode. Specifically, we examine whether auditors are implementing the risk-based audit mode to evaluate corporate governance before distributing audit resources. The results show that under the internal control-based audit mode, the relationship between audit effort and corporate governance was weak. However, implementation of the risk-based mode required by the new auditing standards has significantly enhanced the relationship between audit effort and corporate governance. Since the change in audit mode, the Big Ten have demonstrated a significantly better grasp of governance risk and allocated their audit effort accordingly, relative to smaller firms. The empirical evidence indicates that auditors have adjusted their audit strategy to meet the regulations, risk-based auditing is being achieved to a degree, reasonable and effective corporate governance helps to optimize audit resource allocation, and smaller auditing firms in particular should urgently strengthen their risk-based auditing capability. Overall, our findings imply that the mandatory switch to risk-based auditing has optimized audit effort in China.

  3. Epistemology and Empirical Investigation

    DEFF Research Database (Denmark)

    Ahlström, Kristoffer

    2008-01-01

    Recently, Hilary Kornblith has argued that epistemological investigation is substantially empirical. In the present paper, I will ¿rst show that his claim is not contingent upon the further and, admittedly, controversial assumption that all objects of epistemological investigation are natural kinds....... Then, I will argue that, contrary to what Kornblith seems to assume, this methodological contention does not imply that there is no need for attending to our epistemic concepts in epistemology. Understanding the make-up of our concepts and, in particular, the purposes they ¿ll, is necessary...

  4. GATS Mode 4 Negotiation and Policy Options

    Directory of Open Access Journals (Sweden)

    Kil-Sang Yoo

    2004-06-01

    Full Text Available This study reviews the characteristics and issues of GATS Mode 4 and guesses the effects of Mode 4 liberalization on Korean economy and labor market to suggest policy options to Korea. Mode 4 negotiation started from the trade perspective, however, since Mode 4 involves international labor migration, it also has migration perspective. Thus developed countries, that have competitiveness in service sector, are interested in free movement of skilled workers such as intra-company transferees and business visitors. On the other hand, developing countries, that have little competitiveness in service sector, are interested in free movement of low-skilled workers. Empirical studies predict that the benefits of Mode 4 liberalization will be focused on developed countries rather than developing countries. The latter may suffer from brain drain and reduction of labor supply. Nevertheless developed countries are reluctant to Mode 4 negotiation because they can utilize skilled workers from developing countries by use of their own temporary visa programs. They are interested in Mode 4 related with Mode 3 in order to ease direct investment and movement of natural persons to developing countries. Regardless of the direction of a single undertaking of Mode 4 negotiation, the net effects of Mode 4 liberalization on Korean economy and labor market may be negative. The Korean initial offer on Mode 4 is the same as the UR offer. Since Korean position on Mode 4 is most defensive, it is hard to expect that Korean position will be accepted as the single undertaking of Mode 4 negotiation. Thus Korea has to prepare strategic package measures to minimize the costs of Mode 4 liberalization and improve competitiveness of service sector.

  5. Empirical microeconomics action functionals

    Science.gov (United States)

    Baaquie, Belal E.; Du, Xin; Tanputraman, Winson

    2015-06-01

    A statistical generalization of microeconomics has been made in Baaquie (2013), where the market price of every traded commodity, at each instant of time, is considered to be an independent random variable. The dynamics of commodity market prices is modeled by an action functional-and the focus of this paper is to empirically determine the action functionals for different commodities. The correlation functions of the model are defined using a Feynman path integral. The model is calibrated using the unequal time correlation of the market commodity prices as well as their cubic and quartic moments using a perturbation expansion. The consistency of the perturbation expansion is verified by a numerical evaluation of the path integral. Nine commodities drawn from the energy, metal and grain sectors are studied and their market behavior is described by the model to an accuracy of over 90% using only six parameters. The paper empirically establishes the existence of the action functional for commodity prices that was postulated to exist in Baaquie (2013).

  6. Empirical particle transport model for tokamaks

    International Nuclear Information System (INIS)

    Petravic, M.; Kuo-Petravic, G.

    1986-08-01

    A simple empirical particle transport model has been constructed with the purpose of gaining insight into the L- to H-mode transition in tokamaks. The aim was to construct the simplest possible model which would reproduce the measured density profiles in the L-regime, and also produce a qualitatively correct transition to the H-regime without having to assume a completely different transport mode for the bulk of the plasma. Rather than using completely ad hoc constructions for the particle diffusion coefficient, we assume D = 1/5 chi/sub total/, where chi/sub total/ ≅ chi/sub e/ is the thermal diffusivity, and then use the κ/sub e/ = n/sub e/chi/sub e/ values derived from experiments. The observed temperature profiles are then automatically reproduced, but nontrivially, the correct density profiles are also obtained, for realistic fueling rates and profiles. Our conclusion is that it is sufficient to reduce the transport coefficients within a few centimeters of the surface to produce the H-mode behavior. An additional simple assumption, concerning the particle mean-free path, leads to a convective transport term which reverses sign a few centimeters inside the surface, as required by the H-mode density profiles

  7. What 'empirical turn in bioethics'?

    Science.gov (United States)

    Hurst, Samia

    2010-10-01

    Uncertainty as to how we should articulate empirical data and normative reasoning seems to underlie most difficulties regarding the 'empirical turn' in bioethics. This article examines three different ways in which we could understand 'empirical turn'. Using real facts in normative reasoning is trivial and would not represent a 'turn'. Becoming an empirical discipline through a shift to the social and neurosciences would be a turn away from normative thinking, which we should not take. Conducting empirical research to inform normative reasoning is the usual meaning given to the term 'empirical turn'. In this sense, however, the turn is incomplete. Bioethics has imported methodological tools from empirical disciplines, but too often it has not imported the standards to which researchers in these disciplines are held. Integrating empirical and normative approaches also represents true added difficulties. Addressing these issues from the standpoint of debates on the fact-value distinction can cloud very real methodological concerns by displacing the debate to a level of abstraction where they need not be apparent. Ideally, empirical research in bioethics should meet standards for empirical and normative validity similar to those used in the source disciplines for these methods, and articulate these aspects clearly and appropriately. More modestly, criteria to ensure that none of these standards are completely left aside would improve the quality of empirical bioethics research and partly clear the air of critiques addressing its theoretical justification, when its rigour in the particularly difficult context of interdisciplinarity is what should be at stake.

  8. EGG: Empirical Galaxy Generator

    Science.gov (United States)

    Schreiber, C.; Elbaz, D.; Pannella, M.; Merlin, E.; Castellano, M.; Fontana, A.; Bourne, N.; Boutsia, K.; Cullen, F.; Dunlop, J.; Ferguson, H. C.; Michałowski, M. J.; Okumura, K.; Santini, P.; Shu, X. W.; Wang, T.; White, C.

    2018-04-01

    The Empirical Galaxy Generator (EGG) generates fake galaxy catalogs and images with realistic positions, morphologies and fluxes from the far-ultraviolet to the far-infrared. The catalogs are generated by egg-gencat and stored in binary FITS tables (column oriented). Another program, egg-2skymaker, is used to convert the generated catalog into ASCII tables suitable for ingestion by SkyMaker (ascl:1010.066) to produce realistic high resolution images (e.g., Hubble-like), while egg-gennoise and egg-genmap can be used to generate the low resolution images (e.g., Herschel-like). These tools can be used to test source extraction codes, or to evaluate the reliability of any map-based science (stacking, dropout identification, etc.).

  9. Determinação de compostos nitrogenados aromáticos em alcatrão de carvão através da cromatografia gasosa bidimensional abrangente acoplada à espectrometria de massas

    OpenAIRE

    Juliana Macedo da Silva

    2014-01-01

    A cromatografia gasosa bidimensional abrangente (GC×GC) é uma excelente técnica analítica para a determinação de diversos compostos em matrizes complexas, como é o caso do alcatrão de carvão, objeto deste estudo. O alcatrão foi obtido através do processo de pirólise e submetido à análise por GC×GC visando a especiação de compostos nitrogenados aromáticos. A GC×GC acoplada à espectrometria de massas com analisadores do tipo quadrupolar (qMS) e por tempo de voo (TOFMS) foram utilizados para a d...

  10. Birds of the Mongol Empire

    OpenAIRE

    Eugene N. Anderson

    2016-01-01

    The Mongol Empire, the largest contiguous empire the world has ever known, had, among other things, a goodly number of falconers, poultry raisers, birdcatchers, cooks, and other experts on various aspects of birding. We have records of this, largely in the Yinshan Zhengyao, the court nutrition manual of the Mongol empire in China (the Yuan Dynasty). It discusses in some detail 22 bird taxa, from swans to chickens. The Huihui Yaofang, a medical encyclopedia, lists ten taxa used medicinally. Ma...

  11. Empirical techniques in finance

    CERN Document Server

    Bhar, Ramaprasad

    2005-01-01

    This book offers the opportunity to study and experience advanced empi- cal techniques in finance and in general financial economics. It is not only suitable for students with an interest in the field, it is also highly rec- mended for academic researchers as well as the researchers in the industry. The book focuses on the contemporary empirical techniques used in the analysis of financial markets and how these are implemented using actual market data. With an emphasis on Implementation, this book helps foc- ing on strategies for rigorously combing finance theory and modeling technology to extend extant considerations in the literature. The main aim of this book is to equip the readers with an array of tools and techniques that will allow them to explore financial market problems with a fresh perspective. In this sense it is not another volume in eco- metrics. Of course, the traditional econometric methods are still valid and important; the contents of this book will bring in other related modeling topics tha...

  12. H-mode physics

    International Nuclear Information System (INIS)

    Itoh, Sanae.

    1991-06-01

    After the discovery of the H-mode in ASDEX ( a tokamak in Germany ) the transition between the L-mode ( Low confinement mode ) and H-mode ( High confinement mode ) has been observed in many tokamaks in the world. The H-mode has made a breakthrough in improving the plasma parameters and has been recognized to be a universal phenomena. Since its discovery, the extensive studies both in experiments and in theory have been made. The research on H-mode has been casting new problems of an anomalous transport across the magnetic surface. This series of lectures will provide a brief review of experiments for explaining H-mode and a model theory of H-mode transition based on the electric field bifurcation. If the time is available, a new theoretical model of the temporal evolution of the H-mode will be given. (author)

  13. Final Empirical Test Case Specification

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Heiselberg, Per

    This document includes the empirical specification on the IEA task of evaluation building energy simulation computer programs for the Double Skin Facades (DSF) constructions. There are two approaches involved into this procedure, one is the comparative approach and another is the empirical one....

  14. Remembrances of Empires Past

    Directory of Open Access Journals (Sweden)

    Robert Aldrich

    2010-03-01

    Full Text Available This paper argues that the colonial legacy is ever present in contemporary Europe. For a generation, most Europeans largely tried, publicly, to forget the colonial past, or remembered it only through the rose-coloured lenses of nostalgia; now the pendulum has swung to memory of that past – even perhaps, in the views of some, to a surfeit of memory, where each group agitates for its own version of history, its own recognition in laws and ceremonies, its own commemoration in museums and monuments, the valorization or repatriation of its own art and artefacts. Word such as ‘invasion,’ ‘racism’ and ‘genocide’ are emotional terms that provoke emotional reactions. Whether leaders should apologize for wrongs of the past – and which wrongs – remains a highly sensitive issue. The ‘return of the colonial’ thus has to do with ethics and politics as well as with history, and can link to statements of apology or recognition, legislation about certain views of history, monetary compensation, repatriation of objects, and—perhaps most importantly—redefinition of national identity and policy. The colonial flags may have been lowered, but many barricades seem to have been raised. Private memories—of loss of land, of unacknowledged service, of political, economic, social and cultural disenfranchisement, but also on the other side of defeat, national castigation and self-flagellation—have been increasingly public. Monuments and museums act not only as sites of history but as venues for political agitation and forums for academic debate – differences of opinion that have spread to the streets. Empire has a long after-life.

  15. Empirical Support for Perceptual Conceptualism

    Directory of Open Access Journals (Sweden)

    Nicolás Alejandro Serrano

    2018-03-01

    Full Text Available The main objective of this paper is to show that perceptual conceptualism can be understood as an empirically meaningful position and, furthermore, that there is some degree of empirical support for its main theses. In order to do this, I will start by offering an empirical reading of the conceptualist position, and making three predictions from it. Then, I will consider recent experimental results from cognitive sciences that seem to point towards those predictions. I will conclude that, while the evidence offered by those experiments is far from decisive, it is enough not only to show that conceptualism is an empirically meaningful position but also that there is empirical support for it.

  16. Empire as a Geopolitical Figure

    DEFF Research Database (Denmark)

    Parker, Noel

    2010-01-01

    This article analyses the ingredients of empire as a pattern of order with geopolitical effects. Noting the imperial form's proclivity for expansion from a critical reading of historical sociology, the article argues that the principal manifestation of earlier geopolitics lay not in the nation...... but in empire. That in turn has been driven by a view of the world as disorderly and open to the ordering will of empires (emanating, at the time of geopolitics' inception, from Europe). One implication is that empires are likely to figure in the geopolitical ordering of the globe at all times, in particular...... after all that has happened in the late twentieth century to undermine nationalism and the national state. Empire is indeed a probable, even for some an attractive form of regime for extending order over the disorder produced by globalisation. Geopolitics articulated in imperial expansion is likely...

  17. Mobile Systems Development: An Empirical Study

    DEFF Research Database (Denmark)

    Hosbond, J. H.

    As part of an ongoing study on mobile systems development (MSD), this paper presents preliminary findings of research-in-progress. The debate on mobility in research has so far been dominated by mobile HCI, technological innovations, and socio-technical issues related to new and emerging mobile...... work patterns. This paper is about the development of mobile systems.Based on an on-going empirical study I present four case studies of companies each with different products or services to offer and diverging ways of establishing and sustaining a successful business in the mobile industry. From...... the case studies I propose a five-layered framework for understanding the structure and segmentation of the industry. This leads to an analysis of the different modes of operation within the mobile industry, exemplified by the four case studies.The contribution of this paper is therefore two-fold: (1) I...

  18. Birds of the Mongol Empire

    Directory of Open Access Journals (Sweden)

    Eugene N. Anderson

    2016-09-01

    Full Text Available The Mongol Empire, the largest contiguous empire the world has ever known, had, among other things, a goodly number of falconers, poultry raisers, birdcatchers, cooks, and other experts on various aspects of birding. We have records of this, largely in the Yinshan Zhengyao, the court nutrition manual of the Mongol empire in China (the Yuan Dynasty. It discusses in some detail 22 bird taxa, from swans to chickens. The Huihui Yaofang, a medical encyclopedia, lists ten taxa used medicinally. Marco Polo also made notes on Mongol bird use. There are a few other records. This allows us to draw conclusions about Mongol ornithology, which apparently was sophisticated and detailed.

  19. Modes of winter precipitation variability in the North Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Zorita, E. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Hydrophysik; Saenz, J.; Fernandez, J.; Zubillaga, J. [Bilbao Univ. (Spain)

    2001-07-01

    The modes of variability of winter precipitation in the North Atlantic sector are identified by Empirical Orthogonal Functions Analysis in the NCEP/NCAR global reanalysis data sets. These modes are also present in a gridded precipitation data set over the Western Europe. The large-scale fields of atmospheric seasonal mean circulation, baroclinic activity, evaporation and humidity transport that are connected to the rainfall modes have been also analyzed in order to investigate the physical mechanisms that are causally linked to the rainfall modes. The results indicate that the leading rainfall mode is associated to the North Atlantic oscillation and represents a meridional redistribution of precipitation in the North Atlantic through displacements of the storm tracks. The second mode is related to evaporation anomalies in the Eastern Atlantic that precipitate almost entirely in the Western Atlantic. The third mode seems to be associated to meridional transport of water vapor from the Tropical Atlantic. (orig.)

  20. Interaction of tearing modes

    International Nuclear Information System (INIS)

    Satya, Y.; Schmidt, G.

    1979-01-01

    A fully developed tearing mode modifies the magnetic field profile. The effect of this profile modification on the linear growth rate of a different tearing mode in a slab and cylindrical geometry is investigated

  1. Empirical Legality and Effective Reality

    Directory of Open Access Journals (Sweden)

    Hernán Pringe

    2015-08-01

    Full Text Available The conditions that Kant’s doctrine establishes are examined for the predication of the effective reality of certain empirical objects. It is maintained that a for such a predication, it is necessary to have not only perception but also a certain homogeneity of sensible data, and b the knowledge of the existence of certain empirical objects depends on the application of regulative principles of experience.

  2. Empirical logic and quantum mechanics

    International Nuclear Information System (INIS)

    Foulis, D.J.; Randall, C.H.

    1976-01-01

    This article discusses some of the basic notions of quantum physics within the more general framework of operational statistics and empirical logic (as developed in Foulis and Randall, 1972, and Randall and Foulis, 1973). Empirical logic is a formal mathematical system in which the notion of an operation is primitive and undefined; all other concepts are rigorously defined in terms of such operations (which are presumed to correspond to actual physical procedures). (Auth.)

  3. Empirical Research In Engineering Design

    DEFF Research Database (Denmark)

    Ahmed, Saeema

    2007-01-01

    Increasingly engineering design research involves the use of empirical studies that are conducted within an industrial environment [Ahmed, 2001; Court 1995; Hales 1987]. Research into the use of information by designers or understanding how engineers build up experience are examples of research...... of research issues. This paper describes case studies of empirical research carried out within industry in engineering design focusing upon information, knowledge and experience in engineering design. The paper describes the research methods employed, their suitability for the particular research aims...

  4. Entry Mode and Performance of Nordic Firms

    DEFF Research Database (Denmark)

    Wulff, Jesper

    2015-01-01

    including the proposed moderating effect, on average, yield higher post-entry performance. This study sheds light on inconsistent results found in previous research investigating the impact of international experience and has practical implications for managerial decision-making.......This study investigates whether the relationship between mode of international market entry and non-location bound international experience is weaker for firms that are large or have a high foreign to total sales ratio, labeled multinational experience. Empirical evidence based on 250 foreign...... market entries made by Norwegian, Danish and Swedish firms suggests that the association between equity mode choice and non-location bound international experience diminishes in the presence of higher levels of multinational experience. Furthermore, firms whose entry mode choice is predicted by the model...

  5. Mode-2 social science knowledge production?

    DEFF Research Database (Denmark)

    Kropp, Kristoffer; Blok, Anders

    2011-01-01

    The notion of mode-2 knowledge production points to far-reaching transformations in science-society relations, but few attempts have been made to investigate what growing economic and political demands on research may entail for the social sciences. This case study of new patterns of social science...... knowledge production outlines some major institutional and cognitive changes in Danish academic sociology during 'mode-2' times, from the 1980s onwards. Empirically, we rely on documentary sources and qualitative interviews with Danish sociologists, aiming to reconstruct institutional trajectories...... show how a particular cognitive modality of sociology — 'welfare reflexivity' — has become a dominant form of Danish sociological knowledge production. Welfare reflexivity has proven a viable response to volatile mode-2 policy conditions....

  6. Streaming tearing mode

    Science.gov (United States)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  7. Single-Mode VCSELs

    Science.gov (United States)

    Larsson, Anders; Gustavsson, Johan S.

    The only active transverse mode in a truly single-mode VCSEL is the fundamental mode with a near Gaussian field distribution. A single-mode VCSEL produces a light beam of higher spectral purity, higher degree of coherence and lower divergence than a multimode VCSEL and the beam can be more precisely shaped and focused to a smaller spot. Such beam properties are required in many applications. In this chapter, after discussing applications of single-mode VCSELs, we introduce the basics of fields and modes in VCSELs and review designs implemented for single-mode emission from VCSELs in different materials and at different wavelengths. This includes VCSELs that are inherently single-mode as well as inherently multimode VCSELs where higher-order modes are suppressed by mode selective gain or loss. In each case we present the current state-of-the-art and discuss pros and cons. At the end, a specific example with experimental results is provided and, as a summary, the most promising designs based on current technologies are identified.

  8. Umayyad Relations with Byzantium Empire

    Directory of Open Access Journals (Sweden)

    Mansoor Haidari

    2017-06-01

    Full Text Available This research investigates the political and military relations between Umayyad caliphates with the Byzantine Empire. The aim of this research is to clarify Umayyad caliphate’s relations with the Byzantine Empire. We know that these relations were mostly about war and fight. Because there were always intense conflicts between Muslims and the Byzantine Empire, they had to have an active continuous diplomacy to call truce and settle the disputes. Thus, based on the general policy of the Umayyad caliphs, Christians were severely ignored and segregated within Islamic territories. This segregation of the Christians was highly affected by political relationships. It is worthy of mentioning that Umayyad caliphs brought the governing style of the Sassanid kings and Roman Caesar into the Islamic Caliphate system but they didn’t establish civil institutions and administrative organizations.

  9. Double-mode pulsation

    International Nuclear Information System (INIS)

    Cox, A.N.

    1982-01-01

    Double mode pulsation is a very pervasive phenomenon in stars all over the Hertzsprung-Russell diagram. In order of increasing radius, examples are: ZZ Ceti stars, the sun, the delta Scuti stars, RR Lyrae variables, the β Cephei variables and those related to them, Cepheids, and maybe even the Mira stars. These many modes have been interpreted as both radial and nonradial modes, but in many cases the actual mode has not been clearly identified. Yellow giants seem to be the most simple pulsators with a large majority of the RR Lyrae variables and Cepheids showing only one pulsation period. We limit this review to those very few cases for classical Cepheids and RR Lyrae variables which display two modes. For these we know many facts about these stars, but the actual cause of the pulsation in two modes simultaneously remains unknown

  10. Antipastorialism : Resistant Georgic Mode

    National Research Council Canada - National Science Library

    Zimmerman, Donald

    2000-01-01

    ... celebrations of empire and industry. Writers who could neither own land nor gain the benefits of their own labor often labeled themselves and/or their personae explicitly as exiles, mapping their sense of alienation onto a bucolic tradition...

  11. Acquisition versus greenfield foreign entry : diversification mode choice in Central and Eastern Europe

    NARCIS (Netherlands)

    Dikova, Desislava; Witteloostuijn, Adriaan van

    2005-01-01

    Departing from the traditional transaction cost approach in diversification mode literature, this study investigates the influence of experimental organizational learning on the choice between acquisition and a greenfield investment. We provide empirical support that prior experience with

  12. Streaming gravity mode instability

    International Nuclear Information System (INIS)

    Wang Shui.

    1989-05-01

    In this paper, we study the stability of a current sheet with a sheared flow in a gravitational field which is perpendicular to the magnetic field and plasma flow. This mixing mode caused by a combined role of the sheared flow and gravity is named the streaming gravity mode instability. The conditions of this mode instability are discussed for an ideal four-layer model in the incompressible limit. (author). 5 refs

  13. Dual-Mode Combustor

    Science.gov (United States)

    Trefny, Charles J (Inventor); Dippold, Vance F (Inventor)

    2013-01-01

    A new dual-mode ramjet combustor used for operation over a wide flight Mach number range is described. Subsonic combustion mode is usable to lower flight Mach numbers than current dual-mode scramjets. High speed mode is characterized by supersonic combustion in a free-jet that traverses the subsonic combustion chamber to a variable nozzle throat. Although a variable combustor exit aperture is required, the need for fuel staging to accommodate the combustion process is eliminated. Local heating from shock-boundary-layer interactions on combustor walls is also eliminated.

  14. Antipastorialism : Resistant Georgic Mode

    National Research Council Canada - National Science Library

    Zimmerman, Donald

    2000-01-01

    .... Abolitionists, women, Afro-British slaves, and those who protested land enclosure developed a multivalent, resistant mode of writing, which I name 'antipastoralism', that countered orthodox, poetical...

  15. Nonlinear drift tearing mode

    International Nuclear Information System (INIS)

    Zelenyj, L.M.; Kuznetsova, M.M.

    1989-01-01

    Nonlinear study of magnetic perturbation development under single-mode conditions in collision-free plasma in configurations with the magnetic field shear is investigated. Results are obtained with regard of transverse component of electrical field and its effect on ion dynamics within wide range of ion Larmor radius value and values of magnetic field shear. Increments of nonlinear drift tearing mode are obtained and it is shown that excitation drastic conditions of even linearly stable modes are possible. Mechanism of instability nonlinear stabilization is considered and the value of magnetic island at the saturation threshold is estimeted. Energy of nonlinear drift tearing mode is discussed

  16. Transaction cost determinants and ownership-based entry mode choice: a meta-analytical review

    OpenAIRE

    Hongxin Zhao; Yadong Luo; Taewon Suh

    2004-01-01

    Entry mode choice is a critical ingredient of international entry strategies, and has been voluminously examined in the field. The findings, however, are very mixed, especially with respect to transaction-cost-related factors in determining the ownership-based entry mode choice. This study conducted a meta-analysis to quantitatively summarize the literature and empirically generalize more conclusive findings. Based on the 106 effect sizes of 38 empirical studies, the meta-analysis shows that ...

  17. Gazprom the new russian empire

    International Nuclear Information System (INIS)

    Cosnard, D.

    2004-01-01

    The author analyzes the economical and political impacts of the great Gazprom group, leader in the russian energy domain, in Russia. Already number one of the world gas industry, this Group is becoming the right-hand of the Kremlin. Thus the author wonders on this empire transparency and limits. (A.L.B.)

  18. Phenomenology and the Empirical Turn

    NARCIS (Netherlands)

    Zwier, Jochem; Blok, Vincent; Lemmens, Pieter

    2016-01-01

    This paper provides a phenomenological analysis of postphenomenological philosophy of technology. While acknowledging that the results of its analyses are to be recognized as original, insightful, and valuable, we will argue that in its execution of the empirical turn, postphenomenology forfeits

  19. Empirical ethics as dialogical practice

    NARCIS (Netherlands)

    Widdershoven, G.A.M.; Abma, T.A.; Molewijk, A.C.

    2009-01-01

    In this article, we present a dialogical approach to empirical ethics, based upon hermeneutic ethics and responsive evaluation. Hermeneutic ethics regards experience as the concrete source of moral wisdom. In order to gain a good understanding of moral issues, concrete detailed experiences and

  20. Teaching "Empire of the Sun."

    Science.gov (United States)

    Riet, Fred H. van

    1990-01-01

    A Dutch teacher presents reading, film viewing, and writing activities for "Empire of the Sun," J. G. Ballard's autobiographical account of life as a boy in Shanghai and in a Japanese internment camp during World War II (the subject of Steven Spielberg's film of the same name). Includes objectives, procedures, and several literature,…

  1. Empirical Specification of Utility Functions.

    Science.gov (United States)

    Mellenbergh, Gideon J.

    Decision theory can be applied to four types of decision situations in education and psychology: (1) selection; (2) placement; (3) classification; and (4) mastery. For the application of the theory, a utility function must be specified. Usually the utility function is chosen on a priori grounds. In this paper methods for the empirical assessment…

  2. Empirical Productivity Indices and Indicators

    NARCIS (Netherlands)

    B.M. Balk (Bert)

    2016-01-01

    textabstractThe empirical measurement of productivity change (or difference) by means of indices and indicators starts with the ex post profit/loss accounts of a production unit. Key concepts are profit, leading to indicators, and profitability, leading to indices. The main task for the productivity

  3. EMPIRICAL RESEARCH AND CONGREGATIONAL ANALYSIS ...

    African Journals Online (AJOL)

    empirical research has made to the process of congregational analysis. 1 Part of this ... contextual congegrational analysis – meeting social and divine desires”) at the IAPT .... methodology of a congregational analysis should be regarded as a process. ... essential to create space for a qualitative and quantitative approach.

  4. Empirical processes: theory and applications

    OpenAIRE

    Venturini Sergio

    2005-01-01

    Proceedings of the 2003 Summer School in Statistics and Probability in Torgnon (Aosta, Italy) held by Prof. Jon A. Wellner and Prof. M. Banerjee. The topic presented was the theory of empirical processes with applications to statistics (m-estimation, bootstrap, semiparametric theory).

  5. Empirical laws, regularity and necessity

    NARCIS (Netherlands)

    Koningsveld, H.

    1973-01-01

    In this book I have tried to develop an analysis of the concept of an empirical law, an analysis that differs in many ways from the alternative analyse's found in contemporary literature dealing with the subject.

    1 am referring especially to two well-known views, viz. the regularity and

  6. Empirical analysis of consumer behavior

    NARCIS (Netherlands)

    Huang, Yufeng

    2015-01-01

    This thesis consists of three essays in quantitative marketing, focusing on structural empirical analysis of consumer behavior. In the first essay, he investigates the role of a consumer's skill of product usage, and its imperfect transferability across brands, in her product choice. It shows that

  7. Bridging process-based and empirical approaches to modeling tree growth

    Science.gov (United States)

    Harry T. Valentine; Annikki Makela; Annikki Makela

    2005-01-01

    The gulf between process-based and empirical approaches to modeling tree growth may be bridged, in part, by the use of a common model. To this end, we have formulated a process-based model of tree growth that can be fitted and applied in an empirical mode. The growth model is grounded in pipe model theory and an optimal control model of crown development. Together, the...

  8. Multi-Mode Cavity Accelerator Structure

    International Nuclear Information System (INIS)

    Jiang, Yong; Hirshfield, Jay Leonard

    2016-01-01

    This project aimed to develop a prototype for a novel accelerator structure comprising coupled cavities that are tuned to support modes with harmonically-related eigenfrequencies, with the goal of reaching an acceleration gradient >200 MeV/m and a breakdown rate <10"-"7/pulse/meter. Phase I involved computations, design, and preliminary engineering of a prototype multi-harmonic cavity accelerator structure; plus tests of a bimodal cavity. A computational procedure was used to design an optimized profile for a bimodal cavity with high shunt impedance and low surface fields to maximize the reduction in temperature rise Δ T. This cavity supports the TM010 mode and its 2nd harmonic TM011 mode. Its fundamental frequency is at 12 GHz, to benchmark against the empirical criteria proposed within the worldwide High Gradient collaboration for X-band copper structures; namely, a surface electric field E_s_u_r"m"a"x< 260 MV/m and pulsed surface heating Δ T"m"a"x< 56 °K. With optimized geometry, amplitude and relative phase of the two modes, reductions are found in surface pulsed heating, modified Poynting vector, and total RF power - as compared with operation at the same acceleration gradient using only the fundamental mode.

  9. Multi-Mode Cavity Accelerator Structure

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yong [Yale Univ., New Haven, CT (United States); Hirshfield, Jay Leonard [Omega-P R& D, Inc., New Haven, CT (United States)

    2016-11-10

    This project aimed to develop a prototype for a novel accelerator structure comprising coupled cavities that are tuned to support modes with harmonically-related eigenfrequencies, with the goal of reaching an acceleration gradient >200 MeV/m and a breakdown rate <10-7/pulse/meter. Phase I involved computations, design, and preliminary engineering of a prototype multi-harmonic cavity accelerator structure; plus tests of a bimodal cavity. A computational procedure was used to design an optimized profile for a bimodal cavity with high shunt impedance and low surface fields to maximize the reduction in temperature rise ΔT. This cavity supports the TM010 mode and its 2nd harmonic TM011 mode. Its fundamental frequency is at 12 GHz, to benchmark against the empirical criteria proposed within the worldwide High Gradient collaboration for X-band copper structures; namely, a surface electric field Esurmax< 260 MV/m and pulsed surface heating ΔTmax< 56 °K. With optimized geometry, amplitude and relative phase of the two modes, reductions are found in surface pulsed heating, modified Poynting vector, and total RF power—as compared with operation at the same acceleration gradient using only the fundamental mode.

  10. Microwave plasma mode conversion

    International Nuclear Information System (INIS)

    Torres, H.S.; Sakanaka, P.H.; Villarroel, C.H.

    1985-01-01

    The behavior of hot electrons during the process of laser-produced plasma is studied. The basic equations of mode conversion from electromagnetic waves to electrostatic waves are presented. It is shown by mode conversion, that, the resonant absorption and parametric instabilities appear simultaneously, but in different plasma regions. (M.C.K.) [pt

  11. Excursions through KK modes

    Energy Technology Data Exchange (ETDEWEB)

    Furuuchi, Kazuyuki [Manipal Centre for Natural Sciences, Manipal University,Manipal, Karnataka 576104 (India)

    2016-07-07

    In this article we study Kaluza-Klein (KK) dimensional reduction of massive Abelian gauge theories with charged matter fields on a circle. Since local gauge transformations change position dependence of the charged fields, the decomposition of the charged matter fields into KK modes is gauge dependent. While whole KK mass spectrum is independent of the gauge choice, the mode number depends on the gauge. The masses of the KK modes also depend on the field value of the zero-mode of the extra dimensional component of the gauge field. In particular, one of the KK modes in the KK tower of each massless 5D charged field becomes massless at particular values of the extra-dimensional component of the gauge field. When the extra-dimensional component of the gauge field is identified with the inflaton, this structure leads to recursive cosmological particle productions.

  12. Excursions through KK modes

    International Nuclear Information System (INIS)

    Furuuchi, Kazuyuki

    2016-01-01

    In this article we study Kaluza-Klein (KK) dimensional reduction of massive Abelian gauge theories with charged matter fields on a circle. Since local gauge transformations change position dependence of the charged fields, the decomposition of the charged matter fields into KK modes is gauge dependent. While whole KK mass spectrum is independent of the gauge choice, the mode number depends on the gauge. The masses of the KK modes also depend on the field value of the zero-mode of the extra dimensional component of the gauge field. In particular, one of the KK modes in the KK tower of each massless 5D charged field becomes massless at particular values of the extra-dimensional component of the gauge field. When the extra-dimensional component of the gauge field is identified with the inflaton, this structure leads to recursive cosmological particle productions.

  13. Effect of modes interaction on the resistive wall mode stability

    International Nuclear Information System (INIS)

    Chen Longxi; Wu Bin

    2013-01-01

    Effects of modes interaction on the resistive wall mode (RWM) stability are studied. When considering the modes interaction effects, the linear growth rate of the most unstable (3, 1) mode decreases. After linear evolution, the RWM saturates at the nonlinear phase. The saturation can be attributed to flux piling up on the resistive wall. When some modes exist, the (3, 1) mode saturates at lower level compared with single mode evolution. Meanwhile, the magnetic energy of the (5, 2) mode increases correspondingly, but the magnetic energy saturation level of the (2, 1) mode changes weakly. (authors)

  14. Empirically Testing Thematic Analysis (ETTA)

    DEFF Research Database (Denmark)

    Gildberg, Frederik Alkier; Bradley, Stephen K.; Tingleff, Elllen B.

    2015-01-01

    Text analysis is not a question of a right or wrong way to go about it, but a question of different traditions. These tend to not only give answers to how to conduct an analysis, but also to provide the answer as to why it is conducted in the way that it is. The problem however may be that the li...... for themselves. The advantage of utilizing the presented analytic approach is argued to be the integral empirical testing, which should assure systematic development, interpretation and analysis of the source textual material....... between tradition and tool is unclear. The main objective of this article is therefore to present Empirical Testing Thematic Analysis, a step by step approach to thematic text analysis; discussing strengths and weaknesses, so that others might assess its potential as an approach that they might utilize/develop...

  15. Essays in empirical industrial organization

    OpenAIRE

    Aguiar de Luque, Luis

    2013-01-01

    My PhD thesis consists of three chapters in Empirical Industrial Organization. The first two chapters focus on the relationship between firrm performance and specific public policies. In particular, we analyze the cases of cooperative research and development (R&D) in the European Union and the regulation of public transports in France. The third chapter focuses on copyright protection in the digital era and analyzes the relationship between legal and illegal consumption of di...

  16. Empirical research on Waldorf education

    OpenAIRE

    Randoll, Dirk; Peters, Jürgen

    2015-01-01

    Waldorf education began in 1919 with the first Waldorf School in Stuttgart and nowadays is widespread in many countries all over the world. Empirical research, however, has been rare until the early nineties and Waldorf education has not been discussed within educational science so far. This has changed during the last decades. This article reviews the results of surveys during the last 20 years and is mainly focused on German Waldorf Schools, because most investigations have been done in thi...

  17. Empirical distribution function under heteroscedasticity

    Czech Academy of Sciences Publication Activity Database

    Víšek, Jan Ámos

    2011-01-01

    Roč. 45, č. 5 (2011), s. 497-508 ISSN 0233-1888 Grant - others:GA UK(CZ) GA402/09/0557 Institutional research plan: CEZ:AV0Z10750506 Keywords : Robustness * Convergence * Empirical distribution * Heteroscedasticity Subject RIV: BB - Applied Statistics , Operational Research Impact factor: 0.724, year: 2011 http://library.utia.cas.cz/separaty/2011/SI/visek-0365534.pdf

  18. Expert opinion vs. empirical evidence

    OpenAIRE

    Herman, Rod A; Raybould, Alan

    2014-01-01

    Expert opinion is often sought by government regulatory agencies when there is insufficient empirical evidence to judge the safety implications of a course of action. However, it can be reckless to continue following expert opinion when a preponderance of evidence is amassed that conflicts with this opinion. Factual evidence should always trump opinion in prioritizing the information that is used to guide regulatory policy. Evidence-based medicine has seen a dramatic upturn in recent years sp...

  19. Surface modes in physics

    CERN Document Server

    Sernelius, Bo E

    2011-01-01

    Electromagnetic surface modes are present at all surfaces and interfaces between material of different dielectric properties. These modes have very important effects on numerous physical quantities: adhesion, capillary force, step formation and crystal growth, the Casimir effect etc. They cause surface tension and wetting and they give rise to forces which are important e.g. for the stability of colloids.This book is a useful and elegant approach to the topic, showing how the concept of electromagnetic modes can be developed as a unifying theme for a range of condensed matter physics. The

  20. Study of complex modes

    International Nuclear Information System (INIS)

    Pastrnak, J.W.

    1986-01-01

    This eighteen-month study has been successful in providing the designer and analyst with qualitative guidelines on the occurrence of complex modes in the dynamics of linear structures, and also in developing computer codes for determining quantitatively which vibration modes are complex and to what degree. The presence of complex modes in a test structure has been verified. Finite element analysis of a structure with non-proportional dumping has been performed. A partial differential equation has been formed to eliminate possible modeling errors

  1. Switch mode power supply

    International Nuclear Information System (INIS)

    Kim, Hui Jun

    1993-06-01

    This book concentrates on switch mode power supply. It has four parts, which are introduction of switch mode power supply with DC-DC converter such as Buck converter boost converter, Buck-boost converter and PWM control circuit, explanation for SMPS with DC-DC converter modeling and power mode control, resonance converter like resonance switch, converter, multi resonance converter and series resonance and parallel resonance converters, basic test of SMPS with PWM control circuit, Buck converter, Boost converter, flyback converter, forward converter and IC for control circuit.

  2. Empirical isotropic chemical shift surfaces

    International Nuclear Information System (INIS)

    Czinki, Eszter; Csaszar, Attila G.

    2007-01-01

    A list of proteins is given for which spatial structures, with a resolution better than 2.5 A, are known from entries in the Protein Data Bank (PDB) and isotropic chemical shift (ICS) values are known from the RefDB database related to the Biological Magnetic Resonance Bank (BMRB) database. The structures chosen provide, with unknown uncertainties, dihedral angles φ and ψ characterizing the backbone structure of the residues. The joint use of experimental ICSs of the same residues within the proteins, again with mostly unknown uncertainties, and ab initio ICS(φ,ψ) surfaces obtained for the model peptides For-(l-Ala) n -NH 2 , with n = 1, 3, and 5, resulted in so-called empirical ICS(φ,ψ) surfaces for all major nuclei of the 20 naturally occurring α-amino acids. Out of the many empirical surfaces determined, it is the 13C α ICS(φ,ψ) surface which seems to be most promising for identifying major secondary structure types, α-helix, β-strand, left-handed helix (α D ), and polyproline-II. Detailed tests suggest that Ala is a good model for many naturally occurring α-amino acids. Two-dimensional empirical 13C α - 1 H α ICS(φ,ψ) correlation plots, obtained so far only from computations on small peptide models, suggest the utility of the experimental information contained therein and thus they should provide useful constraints for structure determinations of proteins

  3. Two concepts of empirical ethics.

    Science.gov (United States)

    Parker, Malcolm

    2009-05-01

    The turn to empirical ethics answers two calls. The first is for a richer account of morality than that afforded by bioethical principlism, which is cast as excessively abstract and thin on the facts. The second is for the facts in question to be those of human experience and not some other, unworldly realm. Empirical ethics therefore promises a richer naturalistic ethics, but in fulfilling the second call it often fails to heed the metaethical requirements related to the first. Empirical ethics risks losing the normative edge which necessarily characterizes the ethical, by failing to account for the nature and the logic of moral norms. I sketch a naturalistic theory, teleological expressivism (TE), which negotiates the naturalistic fallacy by providing a more satisfactory means of taking into account facts and research data with ethical implications. The examples of informed consent and the euthanasia debate are used to illustrate the superiority of this approach, and the problems consequent on including the facts in the wrong kind of way.

  4. Evolution of viral virulence: empirical studies

    Science.gov (United States)

    Kurath, Gael; Wargo, Andrew R.

    2016-01-01

    The concept of virulence as a pathogen trait that can evolve in response to selection has led to a large body of virulence evolution theory developed in the 1980-1990s. Various aspects of this theory predict increased or decreased virulence in response to a complex array of selection pressures including mode of transmission, changes in host, mixed infection, vector-borne transmission, environmental changes, host vaccination, host resistance, and co-evolution of virus and host. A fundamental concept is prediction of trade-offs between the costs and benefits associated with higher virulence, leading to selection of optimal virulence levels. Through a combination of observational and experimental studies, including experimental evolution of viruses during serial passage, many of these predictions have now been explored in systems ranging from bacteriophage to viruses of plants, invertebrates, and vertebrate hosts. This chapter summarizes empirical studies of viral virulence evolution in numerous diverse systems, including the classic models myxomavirus in rabbits, Marek's disease virus in chickens, and HIV in humans. Collectively these studies support some aspects of virulence evolution theory, suggest modifications for other aspects, and show that predictions may apply in some virus:host interactions but not in others. Finally, we consider how virulence evolution theory applies to disease management in the field.

  5. Higher Order Mode Fibers

    DEFF Research Database (Denmark)

    Israelsen, Stine Møller

    This PhD thesis considers higher order modes (HOMs) in optical fibers. That includes their excitation and characteristics. Within the last decades, HOMs have been applied both for space multiplexing in optical communications, group velocity dispersion management and sensing among others......-radial polarization as opposed to the linear polarization of the LP0X modes. The effect is investigated numerically in a double cladding fiber with an outer aircladding using a full vectorial modesolver. Experimentally, the bowtie modes are excited using a long period grating and their free space characteristics...... and polarization state are investigated. For this fiber, the onset of the bowtie effect is shown numerically to be LP011. The characteristics usually associated with Bessel-likes modes such as long diffraction free length and selfhealing are shown to be conserved despite the lack of azimuthal symmetry...

  6. Empirical Phenomenology: A Qualitative Research Approach (The ...

    African Journals Online (AJOL)

    Empirical Phenomenology: A Qualitative Research Approach (The Cologne Seminars) ... and practical application of empirical phenomenology in social research. ... and considers its implications for qualitative methods such as interviewing ...

  7. Inertial modes of rigidly rotating neutron stars in Cowling approximation

    International Nuclear Information System (INIS)

    Kastaun, Wolfgang

    2008-01-01

    In this article, we investigate inertial modes of rigidly rotating neutron stars, i.e. modes for which the Coriolis force is dominant. This is done using the assumption of a fixed spacetime (Cowling approximation). We present frequencies and eigenfunctions for a sequence of stars with a polytropic equation of state, covering a broad range of rotation rates. The modes were obtained with a nonlinear general relativistic hydrodynamic evolution code. We further show that the eigenequations for the oscillation modes can be written in a particularly simple form for the case of arbitrary fast but rigid rotation. Using these equations, we investigate some general characteristics of inertial modes, which are then compared to the numerically obtained eigenfunctions. In particular, we derive a rough analytical estimate for the frequency as a function of the number of nodes of the eigenfunction, and find that a similar empirical relation matches the numerical results with unexpected accuracy. We investigate the slow rotation limit of the eigenequations, obtaining two different sets of equations describing pressure and inertial modes. For the numerical computations we only considered axisymmetric modes, while the analytic part also covers nonaxisymmetric modes. The eigenfunctions suggest that the classification of inertial modes by the quantum numbers of the leading term of a spherical harmonic decomposition is artificial in the sense that the largest term is not strongly dominant, even in the slow rotation limit. The reason for the different structure of pressure and inertial modes is that the Coriolis force remains important in the slow rotation limit only for inertial modes. Accordingly, the scalar eigenequation we obtain in that limit is spherically symmetric for pressure modes, but not for inertial modes

  8. Propagating annular modes

    Science.gov (United States)

    Sheshadri, A.; Plumb, R. A.

    2017-12-01

    The leading "annular mode", defined as the dominant EOF of surface pressure or of zonal mean zonal wind variability, appears as a dipolar structure straddling the mean midlatitude jet and thus seems to describe north-south wobbling of the jet latitude. However, extratropical zonal wind anomalies frequently tend to migrate poleward. This behavior can be described by the first two EOFs, the first (AM1) being the dipolar structure, and the second (AM2) having a tripolar structure centered on the mean jet. Taken in isolation, AM1 thus describes a north-south wobbling of the jet position, while AM2 describes a strengthening and narrowing of the jet. However, despite the fact that they are spatially orthogonal, and their corresponding time series temporally orthogonal, AM1 and AM2 are not independent, but show significant lag-correlations which reveal the propagation. The EOFs are not modes of the underlying dynamical system governing the zonal flow evolution. The true modes can be estimated using principal oscillation pattern (POP) analysis. In the troposphere, the leading POPs manifest themselves as a pair of complex conjugate structures with conjugate eigenvalues thus, in reality, constituting a single, complex, mode that describes propagating anomalies. Even though the principal components associated with the two leading EOFs decay at different rates, each decays faster than the true mode. These facts have implications for eddy feedback and the susceptibility of the mode to external perturbations. If one interprets the annular modes as the modes of the system, then simple theory predicts that the response to steady forcing will usually be dominated by AM1 (with the longest time scale). However, such arguments should really be applied to the true modes. Experiments with a simplified GCM show that climate response to perturbations do not necessarily have AM1 structures. Implications of these results for stratosphere-troposphere interactions are explored. The POP

  9. Dosimetric comparison of standard bi-dimensional radiotherapy, mono-isocentric three-dimensional and arc-therapy for a bilateral breast cancer case with ganglionary attack; Comparaison dosimetrique pour un cas de cancer du sein bilateral avec atteinte ganglionnaire de la radiotherapie bidimensionnelle standard, la radiotherapie tridimensionnelle mono-isocentrique et l'arctherapie

    Energy Technology Data Exchange (ETDEWEB)

    Arnaud, A. [Centre Leon-Berard, Lyon (France); Bodez, V.; Alric, K.; Chastel, D.; Mege, A. [Institut Sainte-Catherine, Avignon (France)

    2011-10-15

    The authors report a study which aimed at determining the optimal radiotherapy technique for a patient operated from a bilateral breast cancer with ganglionary attack and peculiar thoracic conformation. A dosimetric study has been performed. Target volumes and lung and heart coverages have been compared for three techniques: bi-dimensional and three-dimensional radiotherapy, and arc-therapy. It appears that arc-therapy would allow a dosimetric and therapeutic duration gain without improving the target volume coverage while increasing doses delivered to organs at risk. Short communication

  10. Temporal structure of neuronal population oscillations with empirical model decomposition

    International Nuclear Information System (INIS)

    Li Xiaoli

    2006-01-01

    Frequency analysis of neuronal oscillation is very important for understanding the neural information processing and mechanism of disorder in the brain. This Letter addresses a new method to analyze the neuronal population oscillations with empirical mode decomposition (EMD). Following EMD of neuronal oscillation, a series of intrinsic mode functions (IMFs) are obtained, then Hilbert transform of IMFs can be used to extract the instantaneous time frequency structure of neuronal oscillation. The method is applied to analyze the neuronal oscillation in the hippocampus of epileptic rats in vivo, the results show the neuronal oscillations have different descriptions during the pre-ictal, seizure onset and ictal periods of the epileptic EEG at the different frequency band. This new method is very helpful to provide a view for the temporal structure of neural oscillation

  11. Science and the British Empire.

    Science.gov (United States)

    Harrison, Mark

    2005-03-01

    The last few decades have witnessed a flowering of interest in the history of science in the British Empire. This essay aims to provide an overview of some of the most important work in this area, identifying interpretative shifts and emerging themes. In so doing, it raises some questions about the analytical framework in which colonial science has traditionally been viewed, highlighting interactions with indigenous scientific traditions and the use of network-based models to understand scientific relations within and beyond colonial contexts.

  12. Empirical logic and tensor products

    International Nuclear Information System (INIS)

    Foulis, D.J.; Randall, C.H.

    1981-01-01

    In our work we are developing a formalism called empirical logic to support a generalization of conventional statistics; the resulting generalization is called operational statistics. We are not attempting to develop or advocate any particular physical theory; rather we are formulating a precision 'language' in which such theories can be expressed, compared, evaluated, and related to laboratory experiments. We believe that only in such a language can the connections between real physical procedures (operations) and physical theories be made explicit and perspicuous. (orig./HSI)

  13. Sparsity guided empirical wavelet transform for fault diagnosis of rolling element bearings

    Science.gov (United States)

    Wang, Dong; Zhao, Yang; Yi, Cai; Tsui, Kwok-Leung; Lin, Jianhui

    2018-02-01

    Rolling element bearings are widely used in various industrial machines, such as electric motors, generators, pumps, gearboxes, railway axles, turbines, and helicopter transmissions. Fault diagnosis of rolling element bearings is beneficial to preventing any unexpected accident and reducing economic loss. In the past years, many bearing fault detection methods have been developed. Recently, a new adaptive signal processing method called empirical wavelet transform attracts much attention from readers and engineers and its applications to bearing fault diagnosis have been reported. The main problem of empirical wavelet transform is that Fourier segments required in empirical wavelet transform are strongly dependent on the local maxima of the amplitudes of the Fourier spectrum of a signal, which connotes that Fourier segments are not always reliable and effective if the Fourier spectrum of the signal is complicated and overwhelmed by heavy noises and other strong vibration components. In this paper, sparsity guided empirical wavelet transform is proposed to automatically establish Fourier segments required in empirical wavelet transform for fault diagnosis of rolling element bearings. Industrial bearing fault signals caused by single and multiple railway axle bearing defects are used to verify the effectiveness of the proposed sparsity guided empirical wavelet transform. Results show that the proposed method can automatically discover Fourier segments required in empirical wavelet transform and reveal single and multiple railway axle bearing defects. Besides, some comparisons with three popular signal processing methods including ensemble empirical mode decomposition, the fast kurtogram and the fast spectral correlation are conducted to highlight the superiority of the proposed method.

  14. Probabilistic empirical prediction of seasonal climate: evaluation and potential applications

    Science.gov (United States)

    Dieppois, B.; Eden, J.; van Oldenborgh, G. J.

    2017-12-01

    Preparing for episodes with risks of anomalous weather a month to a year ahead is an important challenge for governments, non-governmental organisations, and private companies and is dependent on the availability of reliable forecasts. The majority of operational seasonal forecasts are made using process-based dynamical models, which are complex, computationally challenging and prone to biases. Empirical forecast approaches built on statistical models to represent physical processes offer an alternative to dynamical systems and can provide either a benchmark for comparison or independent supplementary forecasts. Here, we present a new evaluation of an established empirical system used to predict seasonal climate across the globe. Forecasts for surface air temperature, precipitation and sea level pressure are produced by the KNMI Probabilistic Empirical Prediction (K-PREP) system every month and disseminated via the KNMI Climate Explorer (climexp.knmi.nl). K-PREP is based on multiple linear regression and built on physical principles to the fullest extent with predictive information taken from the global CO2-equivalent concentration, large-scale modes of variability in the climate system and regional-scale information. K-PREP seasonal forecasts for the period 1981-2016 will be compared with corresponding dynamically generated forecasts produced by operational forecast systems. While there are many regions of the world where empirical forecast skill is extremely limited, several areas are identified where K-PREP offers comparable skill to dynamical systems. We discuss two key points in the future development and application of the K-PREP system: (a) the potential for K-PREP to provide a more useful basis for reference forecasts than those based on persistence or climatology, and (b) the added value of including K-PREP forecast information in multi-model forecast products, at least for known regions of good skill. We also discuss the potential development of

  15. Collective Lyapunov modes

    International Nuclear Information System (INIS)

    Takeuchi, Kazumasa A; Chaté, Hugues

    2013-01-01

    We show, using covariant Lyapunov vectors in addition to standard Lyapunov analysis, that there exists a set of collective Lyapunov modes in large chaotic systems exhibiting collective dynamics. Associated with delocalized Lyapunov vectors, they act collectively on the trajectory and hence characterize the instability of its collective dynamics. We further develop, for globally coupled systems, a connection between these collective modes and the Lyapunov modes in the corresponding Perron–Frobenius equation. We thereby address the fundamental question of the effective dimension of collective dynamics and discuss the extensivity of chaos in the presence of collective dynamics. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Lyapunov analysis: from dynamical systems theory to applications’. (paper)

  16. Empirical reality, empirical causality, and the measurement problem

    International Nuclear Information System (INIS)

    d'Espagnat, B.

    1987-01-01

    Does physics describe anything that can meaningfully be called independent reality, or is it merely operational? Most physicists implicitly favor an intermediate standpoint, which takes quantum physics into account, but which nevertheless strongly holds fast to quite strictly realistic ideas about apparently obvious facts concerning the macro-objects. Part 1 of this article, which is a survey of recent measurement theories, shows that, when made explicit, the standpoint in question cannot be upheld. Part 2 brings forward a proposal for making minimal changes to this standpoint in such a way as to remove such objections. The empirical reality thus constructed is a notion that, to some extent, does ultimately refer to the human means of apprehension and of data processing. It nevertheless cannot be said that it reduces to a mere name just labelling a set of recipes that never fail. It is shown that their usual notion of macroscopic causality must be endowed with similar features

  17. Reconstructing bidimensional scalar field theory models

    International Nuclear Information System (INIS)

    Flores, Gabriel H.; Svaiter, N.F.

    2001-07-01

    In this paper we review how to reconstruct scalar field theories in two dimensional spacetime starting from solvable Scrodinger equations. Theree different Schrodinger potentials are analyzed. We obtained two new models starting from the Morse and Scarf II hyperbolic potencials, the U (θ) θ 2 In 2 (θ 2 ) model and U (θ) = θ 2 cos 2 (In(θ 2 )) model respectively. (author)

  18. Sliding mode control and observation

    CERN Document Server

    Shtessel, Yuri; Fridman, Leonid; Levant, Arie

    2014-01-01

    The sliding mode control methodology has proven effective in dealing with complex dynamical systems affected by disturbances, uncertainties and unmodeled dynamics. Robust control technology based on this methodology has been applied to many real-world problems, especially in the areas of aerospace control, electric power systems, electromechanical systems, and robotics. Sliding Mode Control and Observation represents the first textbook that starts with classical sliding mode control techniques and progresses toward newly developed higher-order sliding mode control and observation algorithms and their applications. The present volume addresses a range of sliding mode control issues, including: *Conventional sliding mode controller and observer design *Second-order sliding mode controllers and differentiators *Frequency domain analysis of conventional and second-order sliding mode controllers *Higher-order sliding mode controllers and differentiators *Higher-order sliding mode observers *Sliding mode disturbanc...

  19. Mode selection laser

    DEFF Research Database (Denmark)

    2014-01-01

    spatial reflector variations, may be combined to generate a laser beam containing a plurality of orthogonal modes. The laser beam may be injected into a few- mode optical fiber, e.g. for the purpose of optical communication. The VCSEL may have intra-cavity contacts (31,37) and a Tunnel junction (33......) for current confinement into the active layer (34). An air-gap layer (102) may be provided between the upper reflector (15) and the SOI wafer (50) acting as a substrate. The lower reflector may be designed as a high-contrast grating (51) by etching....

  20. Magnetic modes in superlattices

    International Nuclear Information System (INIS)

    Oliveira, F.A.

    1990-04-01

    A first discussion of reciprocal propagation of magnetic modes in a superlattice is presented. In the absence of an applied external magnetic field a superllatice made of alternate layers of the type antiferromagnetic-non-magnetic materials presents effects similar to those of phonons in a dielectric superlattice. (A.C.A.S.) [pt

  1. Thermodynamics of Radiation Modes

    Science.gov (United States)

    Pina, Eduardo; de la Selva, Sara Maria Teresa

    2010-01-01

    We study the equilibrium thermodynamics of the electromagnetic radiation in a cavity of a given volume and temperature. We found three levels of description, the thermodynamics of one mode, the thermodynamics of the distribution of frequencies in a band by summing over the frequencies in it and the global thermodynamics by summing over all the…

  2. Expert opinion vs. empirical evidence

    Science.gov (United States)

    Herman, Rod A; Raybould, Alan

    2014-01-01

    Expert opinion is often sought by government regulatory agencies when there is insufficient empirical evidence to judge the safety implications of a course of action. However, it can be reckless to continue following expert opinion when a preponderance of evidence is amassed that conflicts with this opinion. Factual evidence should always trump opinion in prioritizing the information that is used to guide regulatory policy. Evidence-based medicine has seen a dramatic upturn in recent years spurred by examples where evidence indicated that certain treatments recommended by expert opinions increased death rates. We suggest that scientific evidence should also take priority over expert opinion in the regulation of genetically modified crops (GM). Examples of regulatory data requirements that are not justified based on the mass of evidence are described, and it is suggested that expertise in risk assessment should guide evidence-based regulation of GM crops. PMID:24637724

  3. Thermal Operating Modes

    International Nuclear Information System (INIS)

    Bechtel SAIC Company

    2002-01-01

    Higher and lower temperature operating modes (e.g., above and below the boiling point of water) are alternative approaches to managing the heat produced by the radioactive decay of spent nuclear fuel. Current analyses indicate that a repository at the Yucca Mountain site is likely to comply with applicable safety standards regardless of the particular thermal operating mode. Both modes have potential advantages and disadvantages. With a higher temperature operating mode (HTOM), waste packages (WPs) can be placed closer together. This reduces the number of drifts, the required emplacement area, construction costs, and occupational risks to construction workers. In addition, the HTOM would minimize the amount of water that might contact the waste for hundreds of years after closure. On the other hand, higher temperatures introduce uncertainties in the understanding of the long-term performance of the repository because of uncertainties in the thermal effects on WP lifetime and the near-field environment around the drifts. A lower temperature operating mode (LTOM) has the potential to reduce uncertainties in long-term performance of the repository by limiting the effects of temperature on WP lifetime and on the near-field environment around the drifts. Depending on the combination of operating parameters, a LTOM could require construction of additional drifts, a larger emplacement area, increased construction costs, increased occupational risks to construction works, and a longer period of ventilation than a HTOM. The repository design for the potential Yucca Mountain site is flexible and can be constructed and operated in various operating modes to achieve specific technical objectives, accommodate future policy decisions, and use of new information. For example, the flexible design can be operated across a range of temperatures and can be tailored to achieve specific thermal requirements in the future. To accommodate future policy decisions, the repository can be

  4. Different modes of engagement

    DEFF Research Database (Denmark)

    Nickelsen, Niels Christian Mossfeldt

    Assistive robotics are a new factor to be relied upon in caring for the disabled and the elderly. A number of feeding assistive robotics (FAR) appear in the literature. However, very few ethnographic studies have explored the reception. This is the case although there are significant potential...... and for caregivers. In this paper, I take up two ethnographic resources: 1) retrospective studies of the design process of the ‘Bestic’-FAR 2) an empirical study of the reception in a housing institution for the disabled of the ‘Neater-Eater’- FAR. Analysis of this material unravels the intermingling of a number...... robotics?...

  5. Observations on resistive wall modes

    International Nuclear Information System (INIS)

    Gerwin, R.A.; Finn, J.M.

    1996-01-01

    Several results on resistive wall modes and their application to tokamaks are presented. First, it is observed that in the presence of collisional parallel dynamics there is an exact cancellation to lowest order of the dissipative and sound wave effects for an ideal Ohm's law. This is easily traced to the fact that the parallel dynamics occurs along the perturbed magnetic field lines for such electromagnetic modes. Such a cancellation does not occur in the resistive layer of a tearing-like mode. The relevance to models for resistive wall modes using an electrostatic Hammett-Perkins type operator to model Landau damping will be discussed. Second, we observe that with an ideal Ohm's law, resistive wall modes can be destabilized by rotation in that part of parameter space in which the ideal MHD modes are stable with the wall at infinity. This effect can easily be explained by interpreting the resistive wall instability in terms of mode coupling between the backward stable MHD mode and a stable mode locked into the wall. Such an effect can occur for very small rotation for tearing-resistive wall modes in which inertia dominates viscosity in the layer, but the mode is stabilized by further rotation. For modes for which viscosity dominates in the layer, rotation is purely stabilizing. For both tearing models, a somewhat higher rotation frequency gives stability essentially whenever the tearing mode is stable with a perfectly conducting wall. These tearing/resistive wall results axe also simply explained in terms of mode coupling. It has been shown that resonant external ideal modes can be stabilized in the presence of resistive wall and resistive plasma with rotation of order the nominal tearing mode growth rate. We show that these modes behave as resistive wall tearing modes in the sense above. This strengthens the suggestion that rotational stabilization of the external kink with a resistive wall is due to the presence of resistive layers, even for ideal modes

  6. An empirical system for probabilistic seasonal climate prediction

    Science.gov (United States)

    Eden, Jonathan; van Oldenborgh, Geert Jan; Hawkins, Ed; Suckling, Emma

    2016-04-01

    Preparing for episodes with risks of anomalous weather a month to a year ahead is an important challenge for governments, non-governmental organisations, and private companies and is dependent on the availability of reliable forecasts. The majority of operational seasonal forecasts are made using process-based dynamical models, which are complex, computationally challenging and prone to biases. Empirical forecast approaches built on statistical models to represent physical processes offer an alternative to dynamical systems and can provide either a benchmark for comparison or independent supplementary forecasts. Here, we present a simple empirical system based on multiple linear regression for producing probabilistic forecasts of seasonal surface air temperature and precipitation across the globe. The global CO2-equivalent concentration is taken as the primary predictor; subsequent predictors, including large-scale modes of variability in the climate system and local-scale information, are selected on the basis of their physical relationship with the predictand. The focus given to the climate change signal as a source of skill and the probabilistic nature of the forecasts produced constitute a novel approach to global empirical prediction. Hindcasts for the period 1961-2013 are validated against observations using deterministic (correlation of seasonal means) and probabilistic (continuous rank probability skill scores) metrics. Good skill is found in many regions, particularly for surface air temperature and most notably in much of Europe during the spring and summer seasons. For precipitation, skill is generally limited to regions with known El Niño-Southern Oscillation (ENSO) teleconnections. The system is used in a quasi-operational framework to generate empirical seasonal forecasts on a monthly basis.

  7. A global empirical system for probabilistic seasonal climate prediction

    Science.gov (United States)

    Eden, J. M.; van Oldenborgh, G. J.; Hawkins, E.; Suckling, E. B.

    2015-12-01

    Preparing for episodes with risks of anomalous weather a month to a year ahead is an important challenge for governments, non-governmental organisations, and private companies and is dependent on the availability of reliable forecasts. The majority of operational seasonal forecasts are made using process-based dynamical models, which are complex, computationally challenging and prone to biases. Empirical forecast approaches built on statistical models to represent physical processes offer an alternative to dynamical systems and can provide either a benchmark for comparison or independent supplementary forecasts. Here, we present a simple empirical system based on multiple linear regression for producing probabilistic forecasts of seasonal surface air temperature and precipitation across the globe. The global CO2-equivalent concentration is taken as the primary predictor; subsequent predictors, including large-scale modes of variability in the climate system and local-scale information, are selected on the basis of their physical relationship with the predictand. The focus given to the climate change signal as a source of skill and the probabilistic nature of the forecasts produced constitute a novel approach to global empirical prediction. Hindcasts for the period 1961-2013 are validated against observations using deterministic (correlation of seasonal means) and probabilistic (continuous rank probability skill scores) metrics. Good skill is found in many regions, particularly for surface air temperature and most notably in much of Europe during the spring and summer seasons. For precipitation, skill is generally limited to regions with known El Niño-Southern Oscillation (ENSO) teleconnections. The system is used in a quasi-operational framework to generate empirical seasonal forecasts on a monthly basis.

  8. Boosting Majorana Zero Modes

    Directory of Open Access Journals (Sweden)

    Torsten Karzig

    2013-11-01

    Full Text Available One-dimensional topological superconductors are known to host Majorana zero modes at domain walls terminating the topological phase. Their non-Abelian nature allows for processing quantum information by braiding operations that are insensitive to local perturbations, making Majorana zero modes a promising platform for topological quantum computation. Motivated by the ultimate goal of executing quantum-information processing on a finite time scale, we study domain walls moving at a constant velocity. We exploit an effective Lorentz invariance of the Hamiltonian to obtain an exact solution of the associated quasiparticle spectrum and wave functions for arbitrary velocities. Essential features of the solution have a natural interpretation in terms of the familiar relativistic effects of Lorentz contraction and time dilation. We find that the Majorana zero modes remain stable as long as the domain wall moves at subluminal velocities with respect to the effective speed of light of the system. However, the Majorana bound state dissolves into a continuous quasiparticle spectrum after the domain wall propagates at luminal or even superluminal velocities. This relativistic catastrophe implies that there is an upper limit for possible braiding frequencies even in a perfectly clean system with an arbitrarily large topological gap. We also exploit our exact solution to consider domain walls moving past static impurities present in the system.

  9. Modelos lineares e não lineares inteiros para problemas da mochila bidimensional restrita a 2 estágios Linear and nonlinear integer models for constrained two-stage two-dimensional knapsack problems

    Directory of Open Access Journals (Sweden)

    Horacio Hideki Yanasse

    2013-01-01

    Full Text Available Neste trabalho revemos alguns modelos lineares e não lineares inteiros para gerar padrões de corte bidimensionais guilhotinados de 2 estágios, incluindo os casos exato e não exato e restrito e irrestrito. Esses problemas são casos particulares do problema da mochila bidimensional. Apresentamos também novos modelos para gerar esses padrões de corte, baseados em adaptações ou extensões de modelos para gerar padrões de corte bidimensionais restritos 1-grupo. Padrões 2 estágios aparecem em diferentes processos de corte, como, por exemplo, em indústrias de móveis e de chapas de madeira. Os modelos são úteis para a pesquisa e o desenvolvimento de métodos de solução mais eficientes, explorando estruturas particulares, a decomposição do modelo, relaxações do modelo etc. Eles também são úteis para a avaliação do desempenho de heurísticas, já que permitem (pelo menos para problemas de tamanho moderado uma estimativa do gap de otimalidade de soluções obtidas por heurísticas. Para ilustrar a aplicação dos modelos, analisamos os resultados de alguns experimentos computacionais com exemplos da literatura e outros gerados aleatoriamente. Os resultados foram produzidos usando um software comercial conhecido e mostram que o esforço computacional necessário para resolver os modelos pode ser bastante diferente.In this work we review some linear and nonlinear integer models to generate two stage two-dimensional guillotine cutting patterns, including the constrained, non constrained, exact and non exact cases. These problems are particular cases of the two dimensional knapsack problems. We also present new models to generate these cutting patterns, based on adaptations and extensions of models that generate one-group constrained two dimensional cutting patterns. Two stage patterns arise in different cutting processes like, for instance, in the furniture industry and wooden hardboards. The models are useful for the research and

  10. Control Modes in International Service Operations: The Propensity to Franchise

    OpenAIRE

    Karin Fladmoe-Lindquist; Laurent L. Jacque

    1995-01-01

    What determines a service firm's organizational choice between equity-based control and franchising? This question, which has elicited some theoretical answers and a few empirical tests in a domestic setting, has never been addressed in an international context before. This study explains the mode of control chosen in terms of a theoretical framework which borrows from agency theory and transaction cost analysis. The propensity to franchise internationally was found to be directly related to ...

  11. An Empirical Mass Function Distribution

    Science.gov (United States)

    Murray, S. G.; Robotham, A. S. G.; Power, C.

    2018-03-01

    The halo mass function, encoding the comoving number density of dark matter halos of a given mass, plays a key role in understanding the formation and evolution of galaxies. As such, it is a key goal of current and future deep optical surveys to constrain the mass function down to mass scales that typically host {L}\\star galaxies. Motivated by the proven accuracy of Press–Schechter-type mass functions, we introduce a related but purely empirical form consistent with standard formulae to better than 4% in the medium-mass regime, {10}10{--}{10}13 {h}-1 {M}ȯ . In particular, our form consists of four parameters, each of which has a simple interpretation, and can be directly related to parameters of the galaxy distribution, such as {L}\\star . Using this form within a hierarchical Bayesian likelihood model, we show how individual mass-measurement errors can be successfully included in a typical analysis, while accounting for Eddington bias. We apply our form to a question of survey design in the context of a semi-realistic data model, illustrating how it can be used to obtain optimal balance between survey depth and angular coverage for constraints on mass function parameters. Open-source Python and R codes to apply our new form are provided at http://mrpy.readthedocs.org and https://cran.r-project.org/web/packages/tggd/index.html respectively.

  12. Guaranteed performance in reaching mode of sliding mode ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    addresses the design of constant plus proportional rate reaching law-based SMC for second-order ... Reaching mode; sliding mode controlled systems; output tracking ... The uncertainty in the input distribution function g is expressed as.

  13. Mode-to-mode energy transfers in convective patterns

    Indian Academy of Sciences (India)

    Abstract. We investigate the energy transfer between various Fourier modes in a low- dimensional model for thermal convection. We have used the formalism of mode-to-mode energy transfer rate in our calculation. The evolution equations derived using this scheme is the same as those derived using the hydrodynamical ...

  14. Essays on empirical likelihood in economics

    NARCIS (Netherlands)

    Gao, Z.

    2012-01-01

    This thesis intends to exploit the roots of empirical likelihood and its related methods in mathematical programming and computation. The roots will be connected and the connections will induce new solutions for the problems of estimation, computation, and generalization of empirical likelihood.

  15. Empirical training for conditional random fields

    NARCIS (Netherlands)

    Zhu, Zhemin; Hiemstra, Djoerd; Apers, Peter M.G.; Wombacher, Andreas

    2013-01-01

    In this paper (Zhu et al., 2013), we present a practi- cally scalable training method for CRFs called Empir- ical Training (EP). We show that the standard train- ing with unregularized log likelihood can have many maximum likelihood estimations (MLEs). Empirical training has a unique closed form MLE

  16. Intermodal connectivity in Europe, an empirical exploration

    NARCIS (Netherlands)

    de Langen, P.W.; Lases Figueroa, D.M.; van Donselaar, K.H.; Bozuwa, J.

    2017-01-01

    In this paper we analyse the intermodal connectivity in Europe. The empirical analysis is to our knowledge the first empirical analysis of intermodal connections, and is based on a comprehensive database of intermodal connections in Europe. The paper focuses on rail and barge services, as they are

  17. Empirical Moral Philosophy and Teacher Education

    Science.gov (United States)

    Schjetne, Espen; Afdal, Hilde Wågsås; Anker, Trine; Johannesen, Nina; Afdal, Geir

    2016-01-01

    In this paper, we explore the possible contributions of empirical moral philosophy to professional ethics in teacher education. We argue that it is both possible and desirable to connect knowledge of how teachers empirically do and understand professional ethics with normative theories of teachers' professional ethics. Our argument is made in…

  18. Empirical ethics, context-sensitivity, and contextualism.

    Science.gov (United States)

    Musschenga, Albert W

    2005-10-01

    In medical ethics, business ethics, and some branches of political philosophy (multi-culturalism, issues of just allocation, and equitable distribution) the literature increasingly combines insights from ethics and the social sciences. Some authors in medical ethics even speak of a new phase in the history of ethics, hailing "empirical ethics" as a logical next step in the development of practical ethics after the turn to "applied ethics." The name empirical ethics is ill-chosen because of its associations with "descriptive ethics." Unlike descriptive ethics, however, empirical ethics aims to be both descriptive and normative. The first question on which I focus is what kind of empirical research is used by empirical ethics and for which purposes. I argue that the ultimate aim of all empirical ethics is to improve the context-sensitivity of ethics. The second question is whether empirical ethics is essentially connected with specific positions in meta-ethics. I show that in some kinds of meta-ethical theories, which I categorize as broad contextualist theories, there is an intrinsic need for connecting normative ethics with empirical social research. But context-sensitivity is a goal that can be aimed for from any meta-ethical position.

  19. The emerging empirics of evolutionary economic geography

    NARCIS (Netherlands)

    Boschma, R.A.; Frenken, K.

    2011-01-01

    Following last decade’s programmatic papers on Evolutionary Economic Geography, we report on recent empirical advances and how this empirical work can be positioned vis-a`-vis other strands of research in economic geography. First, we review studies on the path dependent nature of clustering, and

  20. The emerging empirics of evolutionary economic geography

    NARCIS (Netherlands)

    Boschma, R.A.; Frenken, K.

    2010-01-01

    Following last decade’s programmatic papers on Evolutionary Economic Geography, we report on recent empirical advances and how this empirical work can be positioned vis-à-vis other strands of research in economic geography. First, we review studies on the path dependent nature of clustering, and how

  1. The emerging empirics of evolutionary economic geography.

    NARCIS (Netherlands)

    Boschma, R.A.; Frenken, K.

    2011-01-01

    Following last decade’s programmatic papers on Evolutionary Economic Geography, we report on recent empirical advances and how this empirical work can be positioned vis-a`-vis other strands of research in economic geography. First, we review studies on the path dependent nature of clustering, and

  2. Azimuthal decomposition of optical modes

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2012-07-01

    Full Text Available This presentation analyses the azimuthal decomposition of optical modes. Decomposition of azimuthal modes need two steps, namely generation and decomposition. An azimuthally-varying phase (bounded by a ring-slit) placed in the spatial frequency...

  3. The Role of Empirical Research in Bioethics

    Science.gov (United States)

    Kon, Alexander A.

    2010-01-01

    There has long been tension between bioethicists whose work focuses on classical philosophical inquiry and those who perform empirical studies on bioethical issues. While many have argued that empirical research merely illuminates current practices and cannot inform normative ethics, others assert that research-based work has significant implications for refining our ethical norms. In this essay, I present a novel construct for classifying empirical research in bioethics into four hierarchical categories: Lay of the Land, Ideal Versus Reality, Improving Care, and Changing Ethical Norms. Through explaining these four categories and providing examples of publications in each stratum, I define how empirical research informs normative ethics. I conclude by demonstrating how philosophical inquiry and empirical research can work cooperatively to further normative ethics. PMID:19998120

  4. Localized Acoustic Surface Modes

    KAUST Repository

    Farhat, Mohamed

    2015-08-04

    We introduce the concept of localized acoustic surface modes (ASMs). We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

  5. Raman amplification of OAM modes

    DEFF Research Database (Denmark)

    Ingerslev, Kasper; Gregg, Patrick; Galili, Michael

    2017-01-01

    The set of fibre modes carrying orbital angular momentum (OAM) is a possible basis for mode division multiplexing. In this regard, fibres supporting OAM modes have been fabricated [1], and optical communication using these fibres, has been demonstrated [2]. A vital part of any long range...

  6. ACCA College English Teaching Mode

    Science.gov (United States)

    Ding, Renlun

    2008-01-01

    This paper elucidates a new college English teaching mode--"ACCA" (Autonomous Cooperative Class-teaching All-round College English Teaching Mode). Integrated theories such as autonomous learning and cooperative learning into one teaching mode, "ACCA", which is being developed and advanced in practice as well, is the achievement…

  7. Fluxon modes in superconducting multilayers

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Madsen, Søren Peder

    2004-01-01

    We show how to construct fluxon modes from plasma modes in the inductively coupled stacked Josephson junctions, and consider some special cases of these fluxon modes analytically. In some cases we can find exact analytical solutions when we choose the bias current in a special way. We also consid...

  8. Standardization of Keyword Search Mode

    Science.gov (United States)

    Su, Di

    2010-01-01

    In spite of its popularity, keyword search mode has not been standardized. Though information professionals are quick to adapt to various presentations of keyword search mode, novice end-users may find keyword search confusing. This article compares keyword search mode in some major reference databases and calls for standardization. (Contains 3…

  9. Empirical Validation of MoDe4SLA - Approach for Managing Service Compositions

    NARCIS (Netherlands)

    Bodenstaff, L.; Wombacher, Andreas; Reichert, M.U.; Abramowicz, Witold

    For companies managing complex Web service compositions, challenges arise which go far beyond simple bilateral contract monitoring. For example,it is not only important to determine whether or not a component (i.e., Web service) in a composition is performing properly, but also to understand what

  10. Customer evaluations of after-sales service contact modes : an empirical analysis of national culture's consequences

    NARCIS (Netherlands)

    Birgelen, van M.; Ruyter, de J.C.; Jong, de A.; Wetzels, M.G.M.

    2001-01-01

    Technological advances extend the after-sales services portfolio from traditional service encounters to voice- and bit-based services. Technology enables service organizations to transcend geographical as well as cultural boundaries. It might even result in geographical convergence, often treated

  11. Correlation of Respiratory Signals and Electrocardiogram Signals via Empirical Mode Decomposition

    KAUST Repository

    El Fiky, Ahmed Osama

    2011-01-01

    research field for signal processing experts to ensure better and clear representation of the different cardiac activities. Given the nonlinear and non-stationary properties of ECGs, it is not a simple task to cancel the undesired noise terms without

  12. Leakage detection in galvanized iron pipelines using ensemble empirical mode decomposition analysis

    Science.gov (United States)

    Amin, Makeen; Ghazali, M. Fairusham

    2015-05-01

    There are many numbers of possible approaches to detect leaks. Some leaks are simply noticeable when the liquids or water appears on the surface. However many leaks do not find their way to the surface and the existence has to be check by analysis of fluid flow in the pipeline. The first step is to determine the approximate position of leak. This can be done by isolate the sections of the mains in turn and noting which section causes a drop in the flow. Next approach is by using sensor to locate leaks. This approach are involves strain gauge pressure transducers and piezoelectric sensor. the occurrence of leaks and know its exact location in the pipeline by using specific method which are Acoustic leak detection method and transient method. The objective is to utilize the signal processing technique in order to analyse leaking in the pipeline. With this, an EEMD method will be applied as the analysis method to collect and analyse the data.

  13. Spin and isospin modes

    International Nuclear Information System (INIS)

    Suzuki, T.; Sagawa, H.

    2000-01-01

    Complete text of publication follows. Spin and isospin modes in nuclei are investigated. We discuss some of the following topics. 1. Spin-dipole excitations in 12 C and 16 O are studied (1). Effects of tensor and spin-orbit interactions on the distribution of the strengths are investigated, and neutral current neutrino scattering cross sections in 16 O are obtained for heavy-flavor neutrinos from the supernovae. 2. Gamow-Teller (GT) and spin-dipole (SD) modes in 208 Bi are investigated. Quenching and fragmentation of the GT strength are discussed (2). SD excitations and electric dipole (E1) transitions between the GT and SD states are studied (3). Calculated E1 strengths are compared with the sum rule values obtained within the 1p-1h and 1p-1h + 2p-2h configuration spaces. 3. Coulomb displacement energy (CDE) of the IAS of 14 Be is calculated, and the effects of the halo on the CDE and the configuration of the halo state are investigated. 4. Spreading width of IAS and isospin dependence of the width are investigated (4). Our formula for the width explains very well the observed isospin dependence (5). (author)

  14. Modes of fossil preservation

    Science.gov (United States)

    Schopf, J.M.

    1975-01-01

    The processes of geologic preservation are important for understanding the organisms represented by fossils. Some fossil differences are due to basic differences in organization of animals and plants, but the interpretation of fossils has also tended to be influenced by modes of preservation. Four modes of preservation generally can be distinguished: (1) Cellular permineralization ("petrifaction") preserves anatomical detail, and, occasionally, even cytologic structures. (2) Coalified compression, best illustrated by structures from coal but characteristic of many plant fossils in shale, preserves anatomical details in distorted form and produces surface replicas (impressions) on enclosing matrix. (3) Authigenic preservation replicates surface form or outline (molds and casts) prior to distortion by compression and, depending on cementation and timing, may intergrade with fossils that have been subject to compression. (4) Duripartic (hard part) preservation is characteristic of fossil skeletal remains, predominantly animal. Molds, pseudomorphs, or casts may form as bulk replacements following dissolution of the original fossil material, usually by leaching. Classification of the kinds of preservation in fossils will aid in identifying the processes responsible for modifying the fossil remains of both animals and plants. ?? 1975.

  15. Policy learning in the Eurozone crisis: modes, power and functionality.

    Science.gov (United States)

    Dunlop, Claire A; Radaelli, Claudio M

    In response to the attacks on the sovereign debt of some Eurozone countries, European Union (EU) leaders have created a set of preventive and corrective policy instruments to coordinate macro-economic policies and reforms. In this article, we deal with the European Semester, a cycle of information exchange, monitoring and surveillance. Countries that deviate from the targets are subjected to increasing monitoring and more severe 'corrective' interventions, in a pyramid of responsive exchanges between governments and EU institutions. This is supposed to generate coordination and convergence towards balanced economies via mechanisms of learning. But who is learning what? Can the EU learn in the 'wrong' mode? We contribute to the literature on theories of the policy process by showing how modes of learning can be operationalized and used in empirical analysis. We use policy learning as theoretical framework to establish empirically the prevalent mode of learning and its implications for both the power of the Commission and the normative question of whether the EU is learning in the 'correct' mode.

  16. Empirical essays on energy economics

    Energy Technology Data Exchange (ETDEWEB)

    Thoenes, Stefan

    2013-06-13

    The main part of this thesis consists of three distinct essays that empirically analyze economic issues related to energy markets in the United States and Europe. The first chapter provides an introduction and discusses the motivation for the different analyses pursued in this thesis. The second chapter examines attention effects in the market for hybrid vehicles. We show that local media coverage, gasoline price changes and unprecedented record gasoline prices have a significant impact on the consumers' attention. As attention is not directly observable, we analyze online search behavior as a proxy for the revealed consumer attention. Our study is based on a unique weekly panel dataset for 19 metropolitan areas in the US. Additionally, we use monthly state-level panel data to show that the adoption rate of hybrid vehicles is robustly related to our measure of attention. Our results show that the consumers' attention fluctuates strongly and systematically. The third chapter shows how the effect of fuel prices varies with the level of electricity demand. It analyzes the relationship between daily prices of electricity, natural gas and carbon emission allowances with a semiparametric varying smooth coefficient cointegration model. This model is used to analyze the market impact of the nuclear moratorium by the German Government in March 2011. Futures prices of electricity, natural gas and emission allowances are used to show that the market efficiently accounts for the suspended capacity and correctly expects that several nuclear plants will not be switched on after the moratorium. In the fourth chapter, we develop a structural vector autoregressive model (VAR) for the German natural gas market. In particular, we illustrate the usefulness of our approach by disentangling the effects of different fundamental influences during four specific events: The financial crisis starting in 2008, the Russian-Ukrainian gas dispute in January 2009, the Libyan civil war

  17. Empirical essays on energy economics

    International Nuclear Information System (INIS)

    Thoenes, Stefan

    2013-01-01

    The main part of this thesis consists of three distinct essays that empirically analyze economic issues related to energy markets in the United States and Europe. The first chapter provides an introduction and discusses the motivation for the different analyses pursued in this thesis. The second chapter examines attention effects in the market for hybrid vehicles. We show that local media coverage, gasoline price changes and unprecedented record gasoline prices have a significant impact on the consumers' attention. As attention is not directly observable, we analyze online search behavior as a proxy for the revealed consumer attention. Our study is based on a unique weekly panel dataset for 19 metropolitan areas in the US. Additionally, we use monthly state-level panel data to show that the adoption rate of hybrid vehicles is robustly related to our measure of attention. Our results show that the consumers' attention fluctuates strongly and systematically. The third chapter shows how the effect of fuel prices varies with the level of electricity demand. It analyzes the relationship between daily prices of electricity, natural gas and carbon emission allowances with a semiparametric varying smooth coefficient cointegration model. This model is used to analyze the market impact of the nuclear moratorium by the German Government in March 2011. Futures prices of electricity, natural gas and emission allowances are used to show that the market efficiently accounts for the suspended capacity and correctly expects that several nuclear plants will not be switched on after the moratorium. In the fourth chapter, we develop a structural vector autoregressive model (VAR) for the German natural gas market. In particular, we illustrate the usefulness of our approach by disentangling the effects of different fundamental influences during four specific events: The financial crisis starting in 2008, the Russian-Ukrainian gas dispute in January 2009, the Libyan civil war in 2011 as

  18. Surface tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Takizuka, Tomonori; Kurita, Gen-ichi; Azumi, Masafumi; Takeda, Tatsuoki

    1985-10-01

    Surface tearing modes in tokamaks are studied numerically and analytically. The eigenvalue problem is solved to obtain the growth rate and the mode structure. We investigate in detail dependences of the growth rate of the m/n = 2/1 resistive MHD modes on the safety factor at the plasma surface, current profile, wall position, and resistivity. The surface tearing mode moves the plasma surface even when the wall is close to the surface. The stability diagram for these modes is presented. (author)

  19. Statistical study of TCV disruptivity and H-mode accessibility

    International Nuclear Information System (INIS)

    Martin, Y.; Deschenaux, C.; Lister, J.B.; Pochelon, A.

    1997-01-01

    Optimising tokamak operation consists of finding a path, in a multidimensional parameter space, which leads to the desired plasma characteristics and avoids hazards regions. Typically the desirable regions are the domain where an L-mode to H-mode transition can occur, and then, in the H-mode, where ELMs and the required high density< y can be maintained. The regions to avoid are those with a high rate of disruptivity. On TCV, learning the safe and successful paths is achieved empirically. This will no longer be possible in a machine like ITER, since only a small percentage of disrupted discharges will be tolerable. An a priori knowledge of the hazardous regions in ITER is therefore mandatory. This paper presents the results of a statistical analysis of the occurrence of disruptions in TCV. (author) 4 figs

  20. TFTR L mode energy confinement related to deuterium influx

    International Nuclear Information System (INIS)

    Strachan, J.D.

    1999-01-01

    Tokamak energy confinement scaling in TFTR L mode and supershot regimes is discussed. The main result is that TFTR L mode plasmas fit the supershot scaling law for energy confinement. In both regimes, plasma transport coefficients increased with increased edge deuterium influx. The common L mode confinement scaling law on TFTR is also inversely proportional to the volume of wall material that is heated to a high temperature, possibly the temperature at which the deuterium sorbed in the material becomes detrapped and highly mobile. The deuterium influx is increased by: (a) increased beam power due to a deeper heated depth in the edge components and (b) decreased plasma current due to an increased wetted area as governed by the empirically observed dependence of the SOL width upon plasma current. (author). Letter-to-the-editor

  1. Fuel-coolant interactions in a jet contact mode

    International Nuclear Information System (INIS)

    Konishi, K.; Isozaki, M.; Imahori, S.; Kondo, S.; Furutani, A.; Brear, D.J.

    1994-01-01

    Molten fuel-coolant interactions in a jet contact mode was studied with respect to the safety of liquid-metal-cooled fast reactors (LMFRs). From a series of molten Wood's metal (melting point: 79 deg. C, density: -8400 kg/m 3 ) jet-water interaction experiments, several distinct modes of interaction behaviors were observed for various combinations of initial temperature conditions of the two fluids. A semi-empirical model for a minimum film boiling temperature criterion was developed and used to reasonably explain the different interaction modes. It was concluded that energetic jet-water interactions are only possible under relatively narrow initial thermal conditions. Preliminary extrapolation of the present results in an oxide fuel-sodium system suggests that mild interactions with short breakup length and coolable debris formation should be most likely in LMFRs. (author)

  2. Empirical data and moral theory. A plea for integrated empirical ethics.

    Science.gov (United States)

    Molewijk, Bert; Stiggelbout, Anne M; Otten, Wilma; Dupuis, Heleen M; Kievit, Job

    2004-01-01

    Ethicists differ considerably in their reasons for using empirical data. This paper presents a brief overview of four traditional approaches to the use of empirical data: "the prescriptive applied ethicists," "the theorists," "the critical applied ethicists," and "the particularists." The main aim of this paper is to introduce a fifth approach of more recent date (i.e. "integrated empirical ethics") and to offer some methodological directives for research in integrated empirical ethics. All five approaches are presented in a table for heuristic purposes. The table consists of eight columns: "view on distinction descriptive-prescriptive sciences," "location of moral authority," "central goal(s)," "types of normativity," "use of empirical data," "method," "interaction empirical data and moral theory," and "cooperation with descriptive sciences." Ethicists can use the table in order to identify their own approach. Reflection on these issues prior to starting research in empirical ethics should lead to harmonization of the different scientific disciplines and effective planning of the final research design. Integrated empirical ethics (IEE) refers to studies in which ethicists and descriptive scientists cooperate together continuously and intensively. Both disciplines try to integrate moral theory and empirical data in order to reach a normative conclusion with respect to a specific social practice. IEE is not wholly prescriptive or wholly descriptive since IEE assumes an interdepence between facts and values and between the empirical and the normative. The paper ends with three suggestions for consideration on some of the future challenges of integrated empirical ethics.

  3. Analysis of mixed mode microwave distribution manifolds

    International Nuclear Information System (INIS)

    White, T.L.

    1982-09-01

    The 28-GHz microwave distribution manifold used in the ELMO Bumpy Torus-Scale (EBT-S) experiments consists of a toroidal metallic cavity, whose dimensions are much greater than a wavelength, fed by a source of microwave power. Equalization of the mixed mode power distribution ot the 24 cavities of EBT-S is accomplished by empirically adjusting the coupling irises which are equally spaced around the manifold. The performance of the manifold to date has been very good, yet no analytical models exist for optimizing manifold transmission efficiency or for scaling this technology to the EBT-P manifold design. The present report develops a general model for mixed mode microwave distribution manifolds based on isotropic plane wave sources of varying amplitudes that are distributed toroidally around the manifold. The calculated manifold transmission efficiency for the most recent EBT-S coupling iris modification is 90%. This agrees with the average measured transmission efficiency. Also, the model predicts the coupling iris areas required to balance the distribution of microwave power while maximizing transmission efficiency, and losses in waveguide feeds connecting the irises to the cavities of EBT are calculated using an approach similar to the calculation of mainfold losses. The model will be used to evaluate EBT-P manifold designs

  4. The Integrated Mode Management Interface

    Science.gov (United States)

    Hutchins, Edwin

    1996-01-01

    Mode management is the processes of understanding the character and consequences of autoflight modes, planning and selecting the engagement, disengagement and transitions between modes, and anticipating automatic mode transitions made by the autoflight system itself. The state of the art is represented by the latest designs produced by each of the major airframe manufacturers, the Boeing 747-400, the Boeing 777, the McDonnell Douglas MD-11, and the Airbus A320/A340 family of airplanes. In these airplanes autoflight modes are selected by manipulating switches on the control panel. The state of the autoflight system is displayed on the flight mode annunciators. The integrated mode management interface (IMMI) is a graphical interface to autoflight mode management systems for aircraft equipped with flight management computer systems (FMCS). The interface consists of a vertical mode manager and a lateral mode manager. Autoflight modes are depicted by icons on a graphical display. Mode selection is accomplished by touching (or mousing) the appropriate icon. The IMMI provides flight crews with an integrated interface to autoflight systems for aircraft equipped with flight management computer systems (FMCS). The current version is modeled on the Boeing glass-cockpit airplanes (747-400, 757/767). It runs on the SGI Indigo workstation. A working prototype of this graphics-based crew interface to the autoflight mode management tasks of glass cockpit airplanes has been installed in the Advanced Concepts Flight Simulator of the CSSRF of NASA Ames Research Center. This IMMI replaces the devices in FMCS equipped airplanes currently known as mode control panel (Boeing), flight guidance control panel (McDonnell Douglas), and flight control unit (Airbus). It also augments the functions of the flight mode annunciators. All glass cockpit airplanes are sufficiently similar that the IMMI could be tailored to the mode management system of any modern cockpit. The IMMI does not replace the

  5. Driving of the solar p-modes by radiative pumping in the upper photosphere

    Science.gov (United States)

    Fontenla, Juan M.; Emslie, A. G.; Moore, Ronald L.

    1989-01-01

    It is shown that one viable driver of the solar p-modes is radiative pumping in the upper photosphere where the opacity is dominated by the negative hydrogen ion. This new option is suggested by the similar magnitudes of two energy flows that have been evaluated by independent empirical methods. The similarity indicates that the p-modes are radiatively pumped in the upper photosphere and therefore provide the required nonradiative cooling.

  6. Introducing Empirical Exercises into Principles of Economics.

    Science.gov (United States)

    McGrath, Eileen L.; Tiemann, Thomas K.

    1985-01-01

    A rationale for requiring undergraduate students to become familiar with the empirical side of economics is presented, and seven exercises that can be used in an introductory course are provided. (Author/RM)

  7. Review essay: empires, ancient and modern.

    Science.gov (United States)

    Hall, John A

    2011-09-01

    This essay drews attention to two books on empires by historians which deserve the attention of sociologists. Bang's model of the workings of the Roman economy powerfully demonstrates the tributary nature of per-industrial tributary empires. Darwin's analysis concentrates on modern overseas empires, wholly different in character as they involved the transportation of consumption items for the many rather than luxury goods for the few. Darwin is especially good at describing the conditions of existence of late nineteenth century empires, noting that their demise was caused most of all by the failure of balance of power politics in Europe. Concluding thoughts are offered about the USA. © London School of Economics and Political Science 2011.

  8. Inland empire logistics GIS mapping project.

    Science.gov (United States)

    2009-01-01

    The Inland Empire has experienced exponential growth in the area of warehousing and distribution facilities within the last decade and it seems that it will continue way into the future. Where are these facilities located? How large are the facilitie...

  9. Teaching Empirical Software Engineering Using Expert Teams

    DEFF Research Database (Denmark)

    Kuhrmann, Marco

    2017-01-01

    Empirical software engineering aims at making software engineering claims measurable, i.e., to analyze and understand phenomena in software engineering and to evaluate software engineering approaches and solutions. Due to the involvement of humans and the multitude of fields for which software...... is crucial, software engineering is considered hard to teach. Yet, empirical software engineering increases this difficulty by adding the scientific method as extra dimension. In this paper, we present a Master-level course on empirical software engineering in which different empirical instruments...... an extra specific expertise that they offer as service to other teams, thus, fostering cross-team collaboration. The paper outlines the general course setup, topics addressed, and it provides initial lessons learned....

  10. Principles Involving Marketing Policies: An Empirical Assessment

    OpenAIRE

    JS Armstrong; Randall L. Schultz

    2005-01-01

    We examined nine marketing textbooks, published since 1927, to see if they contained useful marketing principles. Four doctoral students found 566 normative statements about pricing, product, place, or promotion in these texts. None of these stateinents were supported by empirical evidence. Four raters agreed on only twenty of these 566 statements as providing meaningful principles. Twenty marketing professors rated whether the twenty meaningful principles were correct, supported by empirical...

  11. Sources of Currency Crisis: An Empirical Analysis

    OpenAIRE

    Weber, Axel A.

    1997-01-01

    Two types of currency crisis models coexist in the literature: first generation models view speculative attacks as being caused by economic fundamentals which are inconsistent with a given parity. Second generation models claim self-fulfilling speculation as the main source of a currency crisis. Recent empirical research in international macroeconomics has attempted to distinguish between the sources of currency crises. This paper adds to this literature by proposing a new empirical approach ...

  12. Agency Theory and Franchising: Some Empirical Results

    OpenAIRE

    Francine Lafontaine

    1992-01-01

    This article provides an empirical assessment of various agency-theoretic explanations for franchising, including risk sharing, one-sided moral hazard, and two-sided moral hazard. The empirical models use proxies for factors such as risk, moral hazard, and franchisors' need for capital to explain both franchisors' decisions about the terms of their contracts (royalty rates and up-front franchise fees) and the extent to which they use franchising. In this article, I exploit several new sources...

  13. Gun Laws and Crime: An Empirical Assessment

    OpenAIRE

    Matti Viren

    2012-01-01

    This paper deals with the effect of gun laws on crime. Several empirical analyses are carried to investigate the relationship between five different crime rates and alternative law variables. The tests are based on cross-section data from US sates. Three different law variables are used in the analysis, together with a set of control variables for income, poverty, unemployment and ethnic background of the population. Empirical analysis does not lend support to the notion that crime laws would...

  14. Empirical direction in design and analysis

    CERN Document Server

    Anderson, Norman H

    2001-01-01

    The goal of Norman H. Anderson's new book is to help students develop skills of scientific inference. To accomplish this he organized the book around the ""Experimental Pyramid""--six levels that represent a hierarchy of considerations in empirical investigation--conceptual framework, phenomena, behavior, measurement, design, and statistical inference. To facilitate conceptual and empirical understanding, Anderson de-emphasizes computational formulas and null hypothesis testing. Other features include: *emphasis on visual inspection as a basic skill in experimental analysis to help student

  15. An Empirical Taxonomy of Crowdfunding Intermediaries

    OpenAIRE

    Haas, Philipp; Blohm, Ivo; Leimeister, Jan Marco

    2014-01-01

    Due to the recent popularity of crowdfunding, a broad magnitude of crowdfunding intermediaries has emerged, while research on crowdfunding intermediaries has been largely neglected. As a consequence, existing classifications of crowdfunding intermediaries are conceptual, lack theoretical grounding, and are not empirically validated. Thus, we develop an empirical taxonomy of crowdfunding intermediaries, which is grounded in the theories of two-sided markets and financial intermediation. Integr...

  16. An empirical analysis of Diaspora bonds

    OpenAIRE

    AKKOYUNLU, Şule; STERN, Max

    2018-01-01

    Abstract. This study is the first to investigate theoretically and empirically the determinants of Diaspora Bonds for eight developing countries (Bangladesh, Ethiopia, Ghana, India, Lebanon, Pakistan, the Philippines, and Sri-Lanka) and one developed country - Israel for the period 1951 and 2008. Empirical results are consistent with the predictions of the theoretical model. The most robust variables are the closeness indicator and the sovereign rating, both on the demand-side. The spread is ...

  17. Digital Image Stabilization Method Based on Variational Mode Decomposition and Relative Entropy

    Directory of Open Access Journals (Sweden)

    Duo Hao

    2017-11-01

    Full Text Available Cameras mounted on vehicles frequently suffer from image shake due to the vehicles’ motions. To remove jitter motions and preserve intentional motions, a hybrid digital image stabilization method is proposed that uses variational mode decomposition (VMD and relative entropy (RE. In this paper, the global motion vector (GMV is initially decomposed into several narrow-banded modes by VMD. REs, which exhibit the difference of probability distribution between two modes, are then calculated to identify the intentional and jitter motion modes. Finally, the summation of the jitter motion modes constitutes jitter motions, whereas the subtraction of the resulting sum from the GMV represents the intentional motions. The proposed stabilization method is compared with several known methods, namely, medium filter (MF, Kalman filter (KF, wavelet decomposition (MD method, empirical mode decomposition (EMD-based method, and enhanced EMD-based method, to evaluate stabilization performance. Experimental results show that the proposed method outperforms the other stabilization methods.

  18. Dialogue for emergent order : an empirical study of the development of the organisational mind in a Dutch manufacturing firm

    NARCIS (Netherlands)

    Eijnatten, van F.M.; Dijkstra, L.; van Galen, M.C.; Boiset, M.

    2001-01-01

    This paper contains an empirical study about the introduction of dialogue as a new mode of communication in a Dutch capital-equipment manufacturing firm. The goal of the project is to increase levels of self-organisation, self-reference, and self-transcendence in the company. Over a period of one

  19. Linear stability of tearing modes

    International Nuclear Information System (INIS)

    Cowley, S.C.; Kulsrud, R.M.; Hahm, T.S.

    1986-05-01

    This paper examines the stability of tearing modes in a sheared slab when the width of the tearing layer is much smaller than the ion Larmor radius. The ion response is nonlocal, and the quasineutrality retains its full integal form. An expansion procedure is introduced to solve the quasineutrality equation in powers of the width of the tearing layer over the ion Larmor radius. The expansion procedure is applied to the collisionless and semi-collisional tearing modes. The first order terms in the expansion we find to be strongly stabilizing. The physics of the mode and of the stabilization is discussed. Tearing modes are observed in experiments even though the slab theory predicts stability. It is proposed that these modes grow from an equilibrium with islands at the rational surfaces. If the equilibrium islands are wider than the ion Larmor radius, the mode is unstable when Δ' is positive

  20. Audit mode change, corporate governance

    OpenAIRE

    Limei Cao; Wanfu Li; Limin Zhang

    2015-01-01

    This study investigates changes in audit strategy in China following the introduction of risk-based auditing standards rather than an internal control-based audit mode. Specifically, we examine whether auditors are implementing the risk-based audit mode to evaluate corporate governance before distributing audit resources. The results show that under the internal control-based audit mode, the relationship between audit effort and corporate governance was weak. However, implementation of the ri...

  1. Zero modes and entanglement entropy

    Energy Technology Data Exchange (ETDEWEB)

    Yazdi, Yasaman K. [Perimeter Institute for Theoretical Physics,31 Caroline St. N., Waterloo, ON, N2L 2Y5 (Canada); Department of Physics and Astronomy, University of Waterloo,200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada)

    2017-04-26

    Ultraviolet divergences are widely discussed in studies of entanglement entropy. Also present, but much less understood, are infrared divergences due to zero modes in the field theory. In this note, we discuss the importance of carefully handling zero modes in entanglement entropy. We give an explicit example for a chain of harmonic oscillators in 1D, where a mass regulator is necessary to avoid an infrared divergence due to a zero mode. We also comment on a surprising contribution of the zero mode to the UV-scaling of the entanglement entropy.

  2. Normal modes of Bardeen discs

    International Nuclear Information System (INIS)

    Verdaguer, E.

    1983-01-01

    The short wavelength normal modes of self-gravitating rotating polytropic discs in the Bardeen approximation are studied. The discs' oscillations can be seen in terms of two types of modes: the p-modes whose driving forces are pressure forces and the r-modes driven by Coriolis forces. As a consequence of differential rotation coupling between the two takes place and some mixed modes appear, their properties can be studied under the assumption of weak coupling and it is seen that they avoid the crossing of the p- and r-modes. The short wavelength analysis provides a basis for the classification of the modes, which can be made by using the properties of their phase diagrams. The classification is applied to the large wavelength modes of differentially rotating discs with strong coupling and to a uniformly rotating sequence with no coupling, which have been calculated in previous papers. Many of the physical properties and qualitative features of these modes are revealed by the analysis. (author)

  3. Magnetorheological dampers in shear mode

    International Nuclear Information System (INIS)

    Wereley, N M; Cho, J U; Choi, Y T; Choi, S B

    2008-01-01

    In this study, three types of shear mode damper using magnetorheological (MR) fluids are theoretically analyzed: linear, rotary drum, and rotary disk dampers. The damping performance of these shear mode MR dampers is characterized in terms of the damping coefficient, which is the ratio of the equivalent viscous damping at field-on status to the damping at field-off status. For these three types of shear mode MR damper, the damping coefficient or dynamic range is derived using three different constitutive models: the Bingham–plastic, biviscous, and Herschel–Bulkley models. The impact of constitutive behavior on shear mode MR dampers is theoretically presented and compared

  4. Mode Combinations and International Operations

    DEFF Research Database (Denmark)

    Benito, Gabriel R. G.; Petersen, Bent; Welch, Lawrence S.

    2011-01-01

    reveals that companies tend to combine modes of operation; thereby producing unique foreign operation mode “packages” for given activities and/or countries, and that the packages are liable to be modified over time – providing a potentially important optional path for international expansion. Our data...... key markets (China, UK and USA) as the basis for an exploration of the extent to which, and how and why, companies combine clearly different foreign operation modes. We examine their use of foreign operation mode combinations within given value activities as well as within given countries. The study...

  5. Mode Combinations and International Operations

    DEFF Research Database (Denmark)

    Benito, Gabriel R. G.; Petersen, Bent; Welch, Lawrence S.

    2011-01-01

    reveals that companies tend to combine modes of operation; thereby producing unique foreign operation mode “packages” for given activities and/or countries, and that the packages are liable to be modified over time—providing a potentially important optional path for international expansion. The data show...... markets (China, UK and USA) is used as the basis for an exploration of the extent to which, and how and why, companies combine clearly different foreign operation modes. We examine their use of foreign operation mode combinations within given value activities as well as within given countries. The study...

  6. Ballooning modes or Fourier modes in a toroidal plasma?

    International Nuclear Information System (INIS)

    Connor, J.W.; Taylor, J.B.

    1987-01-01

    The relationship between two different descriptions of eigenmodes in a torus is investigated. In one the eigenmodes are similar to Fourier modes in a cylinder and are highly localized near a particular rational surface. In the other they are the so-called ballooning modes that extend over many rational surfaces. Using a model that represents both drift waves and resistive interchanges the transition from one of these structures to the other is investigated. In this simplified model the transition depends on a single parameter which embodies the competition between toroidal coupling of Fourier modes (which enhances ballooning) and variation in frequency of Fourier modes from one rational surface to another (which diminishes ballooning). As the coupling is increased each Fourier mode acquires a sideband on an adjacent rational surface and these sidebands then expand across the radius to form the extended mode described by the conventional ballooning mode approximation. This analysis shows that the ballooning approximation is appropriate for drift waves in a tokamak but not for resistive interchanges in a pinch. In the latter the conventional ballooning effect is negligible but they may nevertheless show a ballooning feature. This is localized near the same rational surface as the primary Fourier mode and so does not lead to a radially extended structure

  7. An update on the "empirical turn" in bioethics: analysis of empirical research in nine bioethics journals.

    Science.gov (United States)

    Wangmo, Tenzin; Hauri, Sirin; Gennet, Eloise; Anane-Sarpong, Evelyn; Provoost, Veerle; Elger, Bernice S

    2018-02-07

    A review of literature published a decade ago noted a significant increase in empirical papers across nine bioethics journals. This study provides an update on the presence of empirical papers in the same nine journals. It first evaluates whether the empirical trend is continuing as noted in the previous study, and second, how it is changing, that is, what are the characteristics of the empirical works published in these nine bioethics journals. A review of the same nine journals (Bioethics; Journal of Medical Ethics; Journal of Clinical Ethics; Nursing Ethics; Cambridge Quarterly of Healthcare Ethics; Hastings Center Report; Theoretical Medicine and Bioethics; Christian Bioethics; and Kennedy Institute of Ethics Journal) was conducted for a 12-year period from 2004 to 2015. Data obtained was analysed descriptively and using a non-parametric Chi-square test. Of the total number of original papers (N = 5567) published in the nine bioethics journals, 18.1% (n = 1007) collected and analysed empirical data. Journal of Medical Ethics and Nursing Ethics led the empirical publications, accounting for 89.4% of all empirical papers. The former published significantly more quantitative papers than qualitative, whereas the latter published more qualitative papers. Our analysis reveals no significant difference (χ2 = 2.857; p = 0.091) between the proportion of empirical papers published in 2004-2009 and 2010-2015. However, the increasing empirical trend has continued in these journals with the proportion of empirical papers increasing from 14.9% in 2004 to 17.8% in 2015. This study presents the current state of affairs regarding empirical research published nine bioethics journals. In the quarter century of data that is available about the nine bioethics journals studied in two reviews, the proportion of empirical publications continues to increase, signifying a trend towards empirical research in bioethics. The growing volume is mainly attributable to two

  8. Reflective equilibrium and empirical data: third person moral experiences in empirical medical ethics.

    Science.gov (United States)

    De Vries, Martine; Van Leeuwen, Evert

    2010-11-01

    In ethics, the use of empirical data has become more and more popular, leading to a distinct form of applied ethics, namely empirical ethics. This 'empirical turn' is especially visible in bioethics. There are various ways of combining empirical research and ethical reflection. In this paper we discuss the use of empirical data in a special form of Reflective Equilibrium (RE), namely the Network Model with Third Person Moral Experiences. In this model, the empirical data consist of the moral experiences of people in a practice. Although inclusion of these moral experiences in this specific model of RE can be well defended, their use in the application of the model still raises important questions. What precisely are moral experiences? How to determine relevance of experiences, in other words: should there be a selection of the moral experiences that are eventually used in the RE? How much weight should the empirical data have in the RE? And the key question: can the use of RE by empirical ethicists really produce answers to practical moral questions? In this paper we start to answer the above questions by giving examples taken from our research project on understanding the norm of informed consent in the field of pediatric oncology. We especially emphasize that incorporation of empirical data in a network model can reduce the risk of self-justification and bias and can increase the credibility of the RE reached. © 2009 Blackwell Publishing Ltd.

  9. Spatial-mode switchable ring fiber laser based on low mode-crosstalk all-fiber mode MUX/DEMUX

    Science.gov (United States)

    Ren, Fang; Yu, Jinyi; Wang, Jianping

    2018-05-01

    We report an all-fiber ring laser that emits linearly polarized (LP) modes based on the intracavity all-fiber mode multiplexer/demultiplexer (MUX/DEMUX). Multiple LP modes in ring fiber laser are generated by taking advantage of mode MUX/DEMUX. The all-fiber mode MUX/DEMUX are composed of cascaded mode-selective couplers (MSCs). The output lasing mode of the ring fiber laser can be switched among the three lowest-order LP modes by employing combination of a mode MUX and a simple N × 1 optical switch. The slope efficiencies, optical spectra and mode profiles are measured.

  10. Integrated empirical ethics: loss of normativity?

    Science.gov (United States)

    van der Scheer, Lieke; Widdershoven, Guy

    2004-01-01

    An important discussion in contemporary ethics concerns the relevance of empirical research for ethics. Specifically, two crucial questions pertain, respectively, to the possibility of inferring normative statements from descriptive statements, and to the danger of a loss of normativity if normative statements should be based on empirical research. Here we take part in the debate and defend integrated empirical ethical research: research in which normative guidelines are established on the basis of empirical research and in which the guidelines are empirically evaluated by focusing on observable consequences. We argue that in our concrete example normative statements are not derived from descriptive statements, but are developed within a process of reflection and dialogue that goes on within a specific praxis. Moreover, we show that the distinction in experience between the desirable and the undesirable precludes relativism. The normative guidelines so developed are both critical and normative: they help in choosing the right action and in evaluating that action. Finally, following Aristotle, we plead for a return to the view that morality and ethics are inherently related to one another, and for an acknowledgment of the fact that moral judgments have their origin in experience which is always related to historical and cultural circumstances.

  11. Mode of action of the phenylpyrrole fungicide fenpiclonil in Fusarium sulphureum

    NARCIS (Netherlands)

    Jespers, A.B.K.

    1994-01-01

    In the last few decades, plant disease control has become heavily dependent on fungicides. Most modem fungicides were discovered by random synthesis and empirical optimization of lead structures. In general, these fungicides have specific modes of action and meet modem enviromnental

  12. Visual Working Memory in Deaf Children with Diverse Communication Modes: Improvement by Differential Outcomes

    Science.gov (United States)

    Lopez-Crespo, Ginesa; Daza, Maria Teresa; Mendez-Lopez, Magdalena

    2012-01-01

    Although visual functions have been proposed to be enhanced in deaf individuals, empirical studies have not yet established clear evidence on this issue. The present study aimed to determine whether deaf children with diverse communication modes had superior visual memory and whether their performance was improved by the use of differential…

  13. Generation of high order modes

    CSIR Research Space (South Africa)

    Ngcobo, S

    2012-07-01

    Full Text Available with the location of the Laguerre polynomial zeros. The Diffractive optical element is used to shape the TEM00 Gassian beam and force the laser to operate on a higher order TEMp0 Laguerre-Gaussian modes or high order superposition of Laguerre-Gaussian modes...

  14. Homogeneous modes of cosmological instantons

    Energy Technology Data Exchange (ETDEWEB)

    Gratton, Steven; Turok, Neil

    2001-06-15

    We discuss the O(4) invariant perturbation modes of cosmological instantons. These modes are spatially homogeneous in Lorentzian spacetime and thus not relevant to density perturbations. But their properties are important in establishing the meaning of the Euclidean path integral. If negative modes are present, the Euclidean path integral is not well defined, but may nevertheless be useful in an approximate description of the decay of an unstable state. When gravitational dynamics is included, counting negative modes requires a careful treatment of the conformal factor problem. We demonstrate that for an appropriate choice of coordinate on phase space, the second order Euclidean action is bounded below for normalized perturbations and has a finite number of negative modes. We prove that there is a negative mode for many gravitational instantons of the Hawking-Moss or Coleman{endash}De Luccia type, and discuss the associated spectral flow. We also investigate Hawking-Turok constrained instantons, which occur in a generic inflationary model. Implementing the regularization and constraint proposed by Kirklin, Turok and Wiseman, we find that those instantons leading to substantial inflation do not possess negative modes. Using an alternate regularization and constraint motivated by reduction from five dimensions, we find a negative mode is present. These investigations shed new light on the suitability of Euclidean quantum gravity as a potential description of our universe.

  15. Homogeneous modes of cosmological instantons

    International Nuclear Information System (INIS)

    Gratton, Steven; Turok, Neil

    2001-01-01

    We discuss the O(4) invariant perturbation modes of cosmological instantons. These modes are spatially homogeneous in Lorentzian spacetime and thus not relevant to density perturbations. But their properties are important in establishing the meaning of the Euclidean path integral. If negative modes are present, the Euclidean path integral is not well defined, but may nevertheless be useful in an approximate description of the decay of an unstable state. When gravitational dynamics is included, counting negative modes requires a careful treatment of the conformal factor problem. We demonstrate that for an appropriate choice of coordinate on phase space, the second order Euclidean action is bounded below for normalized perturbations and has a finite number of negative modes. We prove that there is a negative mode for many gravitational instantons of the Hawking-Moss or ColemanendashDe Luccia type, and discuss the associated spectral flow. We also investigate Hawking-Turok constrained instantons, which occur in a generic inflationary model. Implementing the regularization and constraint proposed by Kirklin, Turok and Wiseman, we find that those instantons leading to substantial inflation do not possess negative modes. Using an alternate regularization and constraint motivated by reduction from five dimensions, we find a negative mode is present. These investigations shed new light on the suitability of Euclidean quantum gravity as a potential description of our universe

  16. Intelligence and musical mode preference

    DEFF Research Database (Denmark)

    Bonetti, Leonardo; Costa, Marco

    2016-01-01

    The relationship between fluid intelligence and preference for major–minor musical mode was investigated in a sample of 80 university students. Intelligence was assessed by the Raven’s Advanced Progressive Matrices. Musical mode preference was assessed by presenting 14 pairs of musical stimuli...... differences at the cognitive and personality level related to the enjoyment of sad music....

  17. Theory of a beam-induced electromagnetic mode in a magnetized plasma

    International Nuclear Information System (INIS)

    Baumgaertel, K.; Sauer, K.

    1985-01-01

    The theory of a recently discovered plasma wave mode is presented. In a non-Maxwellian high-beta plasma a new electromagnetic mode was detected containing a group of energetic field-aligned electrons. The theory uses the standard method for derivation of the dispersion relation, allowing non-Maxwellian electron distributions and right-hand polarization. The theoretical dispersion relation is compared with the empirical data. This comparison confirmes the existence of a right-hand circularly polarized mode propagating parallel to the external magnetic field. (D.Gy.)

  18. Noise Reduction for Nonlinear Nonstationary Time Series Data using Averaging Intrinsic Mode Function

    Directory of Open Access Journals (Sweden)

    Christofer Toumazou

    2013-07-01

    Full Text Available A novel noise filtering algorithm based on averaging Intrinsic Mode Function (aIMF, which is a derivation of Empirical Mode Decomposition (EMD, is proposed to remove white-Gaussian noise of foreign currency exchange rates that are nonlinear nonstationary times series signals. Noise patterns with different amplitudes and frequencies were randomly mixed into the five exchange rates. A number of filters, namely; Extended Kalman Filter (EKF, Wavelet Transform (WT, Particle Filter (PF and the averaging Intrinsic Mode Function (aIMF algorithm were used to compare filtering and smoothing performance. The aIMF algorithm demonstrated high noise reduction among the performance of these filters.

  19. Experimental data and boundary conditions for a Double - Skin Facade building in transparent insulation mode

    DEFF Research Database (Denmark)

    Larsen, Olena Kalyanova; Heiselberg, Per; Jensen, Rasmus Lund

    was carried out in a full scale test facility ‘The Cube’, in order to compile three sets of high quality experimental data for validation purposes. The data sets are available for preheating mode, external air curtain mode and transparent insulation mode. The objective of this article is to provide the reader...... with all information about the experimental data and measurements, necessary to complete an independent empirical validation of any simulation tool. The article includes detailed information about the experimental apparatus, experimental principles and experimental full-scale test facility ‘The Cube...

  20. Pluvials, Droughts, Energetics, and the Mongol Empire

    Science.gov (United States)

    Hessl, A. E.; Pederson, N.; Baatarbileg, N.

    2012-12-01

    The success of the Mongol Empire, the largest contiguous land empire the world has ever known, is a historical enigma. At its peak in the late 13th century, the empire influenced areas from the Hungary to southern Asia and Persia. Powered by domesticated herbivores, the Mongol Empire grew at the expense of agriculturalists in Eastern Europe, Persia, and China. What environmental factors contributed to the rise of the Mongols? What factors influenced the disintegration of the empire by 1300 CE? Until now, little high resolution environmental data have been available to address these questions. We use tree-ring records of past temperature and water to illuminate the role of energy and water in the evolution of the Mongol Empire. The study of energetics has long been applied to biological and ecological systems but has only recently become a theme in understanding modern coupled natural and human systems (CNH). Because water and energy are tightly linked in human and natural systems, studying their synergies and interactions make it possible to integrate knowledge across disciplines and human history, yielding important lessons for modern societies. We focus on the role of energy and water in the trajectory of an empire, including its rise, development, and demise. Our research is focused on the Orkhon Valley, seat of the Mongol Empire, where recent paleoenvironmental and archeological discoveries allow high resolution reconstructions of past human and environmental conditions for the first time. Our preliminary records indicate that the period 1210-1230 CE, the height of Chinggis Khan's reign is one of the longest and most consistent pluvials in our tree ring reconstruction of interannual drought. Reconstructed temperature derived from five millennium-long records from subalpine forests in Mongolia document warm temperatures beginning in the early 1200's and ending with a plunge into cold temperatures in 1260. Abrupt cooling in central Mongolia at this time is

  1. Symbiotic empirical ethics: a practical methodology.

    Science.gov (United States)

    Frith, Lucy

    2012-05-01

    Like any discipline, bioethics is a developing field of academic inquiry; and recent trends in scholarship have been towards more engagement with empirical research. This 'empirical turn' has provoked extensive debate over how such 'descriptive' research carried out in the social sciences contributes to the distinctively normative aspect of bioethics. This paper will address this issue by developing a practical research methodology for the inclusion of data from social science studies into ethical deliberation. This methodology will be based on a naturalistic conception of ethical theory that sees practice as informing theory just as theory informs practice - the two are symbiotically related. From this engagement with practice, the ways that such theories need to be extended and developed can be determined. This is a practical methodology for integrating theory and practice that can be used in empirical studies, one that uses ethical theory both to explore the data and to draw normative conclusions. © 2010 Blackwell Publishing Ltd.

  2. Reframing Serial Murder Within Empirical Research.

    Science.gov (United States)

    Gurian, Elizabeth A

    2017-04-01

    Empirical research on serial murder is limited due to the lack of consensus on a definition, the continued use of primarily descriptive statistics, and linkage to popular culture depictions. These limitations also inhibit our understanding of these offenders and affect credibility in the field of research. Therefore, this comprehensive overview of a sample of 508 cases (738 total offenders, including partnered groups of two or more offenders) provides analyses of solo male, solo female, and partnered serial killers to elucidate statistical differences and similarities in offending and adjudication patterns among the three groups. This analysis of serial homicide offenders not only supports previous research on offending patterns present in the serial homicide literature but also reveals that empirically based analyses can enhance our understanding beyond traditional case studies and descriptive statistics. Further research based on these empirical analyses can aid in the development of more accurate classifications and definitions of serial murderers.

  3. Wireless and empire geopolitics radio industry and ionosphere in the British Empire 1918-1939

    CERN Document Server

    Anduaga, Aitor

    2009-01-01

    Although the product of consensus politics, the British Empire was based on communications supremacy and the knowledge of the atmosphere. Focusing on science, industry, government, the military, and education, this book studies the relationship between wireless and Empire throughout the interwar period.

  4. Empirical psychology, common sense, and Kant's empirical markers for moral responsibility.

    Science.gov (United States)

    Frierson, Patrick

    2008-12-01

    This paper explains the empirical markers by which Kant thinks that one can identify moral responsibility. After explaining the problem of discerning such markers within a Kantian framework I briefly explain Kant's empirical psychology. I then argue that Kant's empirical markers for moral responsibility--linked to higher faculties of cognition--are not sufficient conditions for moral responsibility, primarily because they are empirical characteristics subject to natural laws. Next. I argue that these markers are not necessary conditions of moral responsibility. Given Kant's transcendental idealism, even an entity that lacks these markers could be free and morally responsible, although as a matter of fact Kant thinks that none are. Given that they are neither necessary nor sufficient conditions, I discuss the status of Kant's claim that higher faculties are empirical markers of moral responsibility. Drawing on connections between Kant's ethical theory and 'common rational cognition' (4:393), I suggest that Kant's theory of empirical markers can be traced to ordinary common sense beliefs about responsibility. This suggestion helps explain both why empirical markers are important and what the limits of empirical psychology are within Kant's account of moral responsibility.

  5. Mode coupling trigger of neoclassical magnetohydrodynamic tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Gianakon, T.A.; Hegna, C.C.; Callen, J.D.

    1997-05-01

    Numerical studies of the nonlinear evolution of coupled magnetohydrodynamic - type tearing modes in three-dimensional toroidal geometry with neoclassical effects are presented. The inclusion of neoclassical physics introduces an additional free-energy source for the nonlinear formation of magnetic islands through the effects of a bootstrap current in Ohm's law. The neoclassical tearing mode is demonstrated to be destabilized in plasmas which are otherwise Δ' stable, albeit once a threshold island width is exceeded. A possible mechanism for exceeding or eliminating this threshold condition is demonstrated based on mode coupling due to toroidicity with a pre-existing instability at the q = 1 surface

  6. Inter-comb synchronization by mode-to-mode locking

    Science.gov (United States)

    Chun, Byung Jae; Kim, Young-Jin; Kim, Seung-Woo

    2016-08-01

    Two combs of fiber femtosecond lasers are synchronized through the optical frequency reference created by injection-locking of a diode laser to a single comb mode. Maintaining a mHz-level narrow linewidth, the optical frequency reference permits two combs to be stabilized by mode-to-mode locking with a relative stability of 1.52  ×  10-16 at 10 s with a frequency slip of 2.46 mHz. This inter-comb synchronization can be utilized for applications such as dual-comb spectroscopy or ultra-short pulse synthesis without extra narrow-linewidth lasers.

  7. Empirical evaluation methods in computer vision

    CERN Document Server

    Christensen, Henrik I

    2002-01-01

    This book provides comprehensive coverage of methods for the empirical evaluation of computer vision techniques. The practical use of computer vision requires empirical evaluation to ensure that the overall system has a guaranteed performance. The book contains articles that cover the design of experiments for evaluation, range image segmentation, the evaluation of face recognition and diffusion methods, image matching using correlation methods, and the performance of medical image processing algorithms. Sample Chapter(s). Foreword (228 KB). Chapter 1: Introduction (505 KB). Contents: Automate

  8. Evaluation of empirical atmospheric diffusion data

    International Nuclear Information System (INIS)

    Horst, T.W.; Doran, J.C.; Nickola, P.W.

    1979-10-01

    A study has been made of atmospheric diffusion over level, homogeneous terrain of contaminants released from non-buoyant point sources up to 100 m in height. Current theories of diffusion are compared to empirical diffusion data, and specific dispersion estimation techniques are recommended which can be implemented with the on-site meteorological instrumentation required by the Nuclear Regulatory Commission. A comparison of both the recommended diffusion model and the NRC diffusion model with the empirical data demonstrates that the predictions of the recommended model have both smaller scatter and less bias, particularly for groundlevel sources

  9. Evaluation of empirical atmospheric diffusion data

    Energy Technology Data Exchange (ETDEWEB)

    Horst, T.W.; Doran, J.C.; Nickola, P.W.

    1979-10-01

    A study has been made of atmospheric diffusion over level, homogeneous terrain of contaminants released from non-buoyant point sources up to 100 m in height. Current theories of diffusion are compared to empirical diffusion data, and specific dispersion estimation techniques are recommended which can be implemented with the on-site meteorological instrumentation required by the Nuclear Regulatory Commission. A comparison of both the recommended diffusion model and the NRC diffusion model with the empirical data demonstrates that the predictions of the recommended model have both smaller scatter and less bias, particularly for ground-level sources.

  10. Empirical Model Building Data, Models, and Reality

    CERN Document Server

    Thompson, James R

    2011-01-01

    Praise for the First Edition "This...novel and highly stimulating book, which emphasizes solving real problems...should be widely read. It will have a positive and lasting effect on the teaching of modeling and statistics in general." - Short Book Reviews This new edition features developments and real-world examples that showcase essential empirical modeling techniques Successful empirical model building is founded on the relationship between data and approximate representations of the real systems that generated that data. As a result, it is essential for researchers who construct these m

  11. Damping Measurements of Plasma Modes

    Science.gov (United States)

    Anderegg, F.; Affolter, M.; Driscoll, C. F.

    2010-11-01

    For azimuthally symmetric plasma modes in a magnesium ion plasma, confined in a 3 Tesla Penning-Malmberg trap with a density of n ˜10^7cm-3, we measure a damping rate of 2s-1plasma column, alters the frequency of the mode from 16 KHz to 192 KHz. The oscillatory fluid displacement is small compared to the wavelength of the mode; in contrast, the fluid velocity, δvf, can be large compared to v. The real part of the frequency satisfies a linear dispersion relation. In long thin plasmas (α> 10) these modes are Trivelpiece-Gould (TG) modes, and for smaller values of α they are Dubin spheroidal modes. However the damping appears to be non-linear; initially large waves have weaker exponential damping, which is not yet understood. Recent theoryootnotetextM.W. Anderson and T.M. O'Neil, Phys. Plasmas 14, 112110 (2007). calculates the damping of TG modes expected from viscosity due to ion-ion collisions; but the measured damping, while having a similar temperature and density dependence, is about 40 times larger than calculated. This discrepancy might be due to an external damping mechanism.

  12. Mode synthesizing atomic force microscopy and mode-synthesizing sensing

    Science.gov (United States)

    Passian, Ali; Thundat, Thomas George; Tetard, Laurene

    2013-05-17

    A method of analyzing a sample that includes applying a first set of energies at a first set of frequencies to a sample and applying, simultaneously with the applying the first set of energies, a second set of energies at a second set of frequencies, wherein the first set of energies and the second set of energies form a multi-mode coupling. The method further includes detecting an effect of the multi-mode coupling.

  13. Dual-cavity mode converter for a fundamental mode output in an over-moded relativistic backward-wave oscillator

    International Nuclear Information System (INIS)

    Li, Jiawei; Huang, Wenhua; Xiao, Renzhen; Bai, Xianchen; Zhang, Yuchuan; Zhang, Xiaowei; Shao, Hao; Chen, Changhua; Zhu, Qi

    2015-01-01

    A dual-cavity TM 02 –TM 01 mode converter is designed for a dual-mode operation over-moded relativistic backward-wave oscillator. With the converter, the fundamental mode output is achieved. Particle-in-cell simulation shows that the efficiency of beam-wave conversion was over 46% and a pureTM 01 mode output was obtained. Effects of end reflection provided by the mode converter were studied. Adequate TM 01 mode feedback provided by the converter enhances conversion efficiency. The distance between the mode converter and extraction cavity critically affect the generation of microwaves depending on the reflection phase of TM 01 mode feedback

  14. Modes of strategic technology partnering Formy realizacji strategicznych partnerstw technologicznych

    Directory of Open Access Journals (Sweden)

    Łukasz Puślecki

    2008-06-01

    Full Text Available The aim of the article was to verify the organizational modes of strategic technological partnering. The author used a classification of modes of technology cooperation in terms of inter-organizational dependence to discuss major trends and characteristics of different forms of inter-firm partnering on the basis of the MERIT-CATI database. In the article the following forms of technological cooperation were presented: joint-ventures (JV, R&D pacts, technology exchange agreements and research contracts, customer-supplier relations, X-licensing as well as R&D contracts. The verification of such forms of technology partnering was made in years 1980-1996 on the basis of the empirical material taken from MERIT-CATI database.

  15. Downside Risk And Empirical Asset Pricing

    NARCIS (Netherlands)

    P. van Vliet (Pim)

    2004-01-01

    textabstractCurrently, the Nobel prize winning Capital Asset Pricing Model (CAPM) celebrates its 40th birthday. Although widely applied in financial management, this model does not fully capture the empirical riskreturn relation of stocks; witness the beta, size, value and momentum effects. These

  16. Empirical analysis of uranium spot prices

    International Nuclear Information System (INIS)

    Morman, M.R.

    1988-01-01

    The objective is to empirically test a market model of the uranium industry that incorporates the notion that, if the resource is viewed as an asset by economic agents, then its own rate of return along with the own rate of return of a competing asset would be a major factor in formulating the price of the resource. The model tested is based on a market model of supply and demand. The supply model incorporates the notion that the decision criteria used by uranium mine owners is to select that extraction rate that maximizes the net present value of their extraction receipts. The demand model uses a concept that allows for explicit recognition of the prospect of arbitrage between a natural-resource market and the market for other capital goods. The empirical approach used for estimation was a recursive or causal model. The empirical results were consistent with the theoretical models. The coefficients of the demand and supply equations had the appropriate signs. Tests for causality were conducted to validate the use of the causal model. The results obtained were favorable. The implication of the findings as related to future studies of exhaustible resources are: (1) in some cases causal models are the appropriate specification for empirical analysis; (2) supply models should incorporate a measure to capture depletion effects

  17. Trade costs in empirical New Economic Geography

    NARCIS (Netherlands)

    Bosker, E.M.; Garretsen, J.H.

    Trade costs are a crucial element of New Economic Geography (NEG) models. Without trade costs there is no role for geography. In empirical NEG studies the unavailability of direct trade cost data calls for the need to approximate these trade costs by introducing a trade cost function. In doing so,

  18. Methods for Calculating Empires in Quasicrystals

    Directory of Open Access Journals (Sweden)

    Fang Fang

    2017-10-01

    Full Text Available This paper reviews the empire problem for quasiperiodic tilings and the existing methods for generating the empires of the vertex configurations in quasicrystals, while introducing a new and more efficient method based on the cut-and-project technique. Using Penrose tiling as an example, this method finds the forced tiles with the restrictions in the high dimensional lattice (the mother lattice that can be cut-and-projected into the lower dimensional quasicrystal. We compare our method to the two existing methods, namely one method that uses the algorithm of the Fibonacci chain to force the Ammann bars in order to find the forced tiles of an empire and the method that follows the work of N.G. de Bruijn on constructing a Penrose tiling as the dual to a pentagrid. This new method is not only conceptually simple and clear, but it also allows us to calculate the empires of the vertex configurations in a defected quasicrystal by reversing the configuration of the quasicrystal to its higher dimensional lattice, where we then apply the restrictions. These advantages may provide a key guiding principle for phason dynamics and an important tool for self error-correction in quasicrystal growth.

  19. Alternative Approaches to Evaluation in Empirical Microeconomics

    Science.gov (United States)

    Blundell, Richard; Dias, Monica Costa

    2009-01-01

    This paper reviews some of the most popular policy evaluation methods in empirical microeconomics: social experiments, natural experiments, matching, instrumental variables, discontinuity design, and control functions. It discusses identification of traditionally used average parameters and more complex distributional parameters. The adequacy,…

  20. Characterizing Student Expectations: A Small Empirical Study

    Science.gov (United States)

    Warwick, Jonathan

    2016-01-01

    This paper describes the results of a small empirical study (n = 130), in which undergraduate students in the Business Faculty of a UK university were asked to express views and expectations relating to the study of a mathematics. Factor analysis is used to identify latent variables emerging from clusters of the measured variables and these are…

  1. EVOLVING AN EMPIRICAL METHODOLOGY DOR DETERMINING ...

    African Journals Online (AJOL)

    The uniqueness of this approach, is that it can be applied to any forest or dynamic feature on the earth, and can enjoy universal application as well. KEY WORDS: Evolving empirical methodology, innovative mathematical model, appropriate interval, remote sensing, forest environment planning and management. Global Jnl ...

  2. Caught between Empires: Ambivalence in Australian Films ...

    African Journals Online (AJOL)

    Caught between Empires: Ambivalence in Australian Films. Greg McCarthy. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for ...

  3. Spitsbergen - Imperialists beyond the British Empire

    NARCIS (Netherlands)

    Kruse, Frigga; Hacquebord, Louwrens

    2012-01-01

    This paper looks at the relationship between Spitsbergen in the European High Arctic and the global British Empire in the first quarter of the twentieth century. Spitsbergen was an uninhabited no man's land and comprised an unknown quantity of natural resources. The concepts of geopolitics and New

  4. An Empirical Investigation into Nigerian ESL Learners ...

    African Journals Online (AJOL)

    General observations indicate that ESL learners in Nigeria tend to manifest fear and anxiety in grammar classes, which could influence their performance negatively or positively. This study examines empirically some of the reasons for some ESL learners' apprehension of grammar classes. The data for the study were ...

  5. Air pollutant taxation: an empirical survey

    International Nuclear Information System (INIS)

    Cansier, D.; Krumm, R.

    1997-01-01

    An empirical analysis of the current taxation of the air pollutants sulphur dioxide, nitrogen oxides and carbon dioxide in the Scandinavian countries, the Netherlands, France and Japan is presented. Political motivation and technical factors such as tax base, rate structure and revenue use are compared. The general concepts of the current polices are characterised

  6. Empirical research on constructing Taiwan's ecoenvironmental ...

    African Journals Online (AJOL)

    In this paper, the material flow indicators and ecological footprint approach structured are adopted to construct eco-environmental stress indicators. We use relevant data to proceed with the empirical analyses on environmental stress and ecological impacts in Taiwan between the years of 1998 and 2007. Analysis of ...

  7. Empirical Bayes Approaches to Multivariate Fuzzy Partitions.

    Science.gov (United States)

    Woodbury, Max A.; Manton, Kenneth G.

    1991-01-01

    An empirical Bayes-maximum likelihood estimation procedure is presented for the application of fuzzy partition models in describing high dimensional discrete response data. The model describes individuals in terms of partial membership in multiple latent categories that represent bounded discrete spaces. (SLD)

  8. Empirically Exploring Higher Education Cultures of Assessment

    Science.gov (United States)

    Fuller, Matthew B.; Skidmore, Susan T.; Bustamante, Rebecca M.; Holzweiss, Peggy C.

    2016-01-01

    Although touted as beneficial to student learning, cultures of assessment have not been examined adequately using validated instruments. Using data collected from a stratified, random sample (N = 370) of U.S. institutional research and assessment directors, the models tested in this study provide empirical support for the value of using the…

  9. Empirically Based Myths: Astrology, Biorhythms, and ATIs.

    Science.gov (United States)

    Ragsdale, Ronald G.

    1980-01-01

    A myth may have an empirical basis through chance occurrence; perhaps Aptitude Treatment Interactions (ATIs) are in this category. While ATIs have great utility in describing, planning, and implementing instruction, few disordinal interactions have been found. Article suggests narrowing of ATI research with replications and estimates of effect…

  10. Transition States from Empirical Force Fields

    DEFF Research Database (Denmark)

    Jensen, Frank; Norrby, Per-Ola

    2003-01-01

    This is an overview of the use of empirical force fields in the study of reaction mechanisms. EVB-type methods (including RFF and MCMM) produce full reaction surfaces by mixing, in the simplest case, known force fields describing reactants and products. The SEAM method instead locates approximate...

  11. Classification of Marital Relationships: An Empirical Approach.

    Science.gov (United States)

    Snyder, Douglas K.; Smith, Gregory T.

    1986-01-01

    Derives an empirically based classification system of marital relationships, employing a multidimensional self-report measure of marital interaction. Spouses' profiles on the Marital Satisfaction Inventory for samples of clinic and nonclinic couples were subjected to cluster analysis, resulting in separate five-group typologies for husbands and…

  12. Empirical scaling for present ohmic heated tokamaks

    International Nuclear Information System (INIS)

    Daughney, C.

    1975-06-01

    Empirical scaling laws are given for the average electron temperature and electron energy confinement time as functions of plasma current, average electron density, effective ion charge, toroidal magnetic field, and major and minor plasma radius. The ohmic heating is classical, and the electron energy transport is anomalous. The present scaling indicates that ohmic-heating becomes ineffective with larger experiments. (U.S.)

  13. Developing empirical relationship between interrill erosion, rainfall ...

    African Journals Online (AJOL)

    In order to develop an empirical relationship for interrill erosion based on rainfall intensity, slope steepness and soil types, an interrill erosion experiment was conducted using laboratory rainfall simulator on three soil types (Vertisols, Cambisols and Leptosols) for the highlands of North Shewa Zone of Oromia Region.

  14. Governance and Human Development: Empirical Evidence from ...

    African Journals Online (AJOL)

    This study empirically investigates the effects of governance on human development in Nigeria. Using annual time series data covering the period 1998 to 2010, obtained from various sources, and employing the classical least squares estimation technique, the study finds that corruption, foreign aid and government ...

  15. Software Development Management: Empirical and Analytical Perspectives

    Science.gov (United States)

    Kang, Keumseok

    2011-01-01

    Managing software development is a very complex activity because it must deal with people, organizations, technologies, and business processes. My dissertation consists of three studies that examine software development management from various perspectives. The first study empirically investigates the impacts of prior experience with similar…

  16. The Italian Footwear Industry: an Empirical Analysis

    OpenAIRE

    Pirolo, Luca; Giustiniano, Luca; Nenni, Maria Elena

    2013-01-01

    This paper aims to provide readers with a deep empirical analysis on the Italian footwear industry in order to investigate the evolution of its structure (trends in sales and production, number of firms and employees, main markets, etc.), together with the identification of the main drivers of competitiveness in order to explain the strategies implemented by local actors.

  17. Multiscale empirical interpolation for solving nonlinear PDEs

    KAUST Repository

    Calo, Victor M.; Efendiev, Yalchin R.; Galvis, Juan; Ghommem, Mehdi

    2014-01-01

    residuals and Jacobians on the fine grid. We use empirical interpolation concepts to evaluate these residuals and Jacobians of the multiscale system with a computational cost which is proportional to the size of the coarse-scale problem rather than the fully

  18. Quantitative analyses of empirical fitness landscapes

    International Nuclear Information System (INIS)

    Szendro, Ivan G; Franke, Jasper; Krug, Joachim; Schenk, Martijn F; De Visser, J Arjan G M

    2013-01-01

    The concept of a fitness landscape is a powerful metaphor that offers insight into various aspects of evolutionary processes and guidance for the study of evolution. Until recently, empirical evidence on the ruggedness of these landscapes was lacking, but since it became feasible to construct all possible genotypes containing combinations of a limited set of mutations, the number of studies has grown to a point where a classification of landscapes becomes possible. The aim of this review is to identify measures of epistasis that allow a meaningful comparison of fitness landscapes and then apply them to the empirical landscapes in order to discern factors that affect ruggedness. The various measures of epistasis that have been proposed in the literature appear to be equivalent. Our comparison shows that the ruggedness of the empirical landscape is affected by whether the included mutations are beneficial or deleterious and by whether intragenic or intergenic epistasis is involved. Finally, the empirical landscapes are compared to landscapes generated with the rough Mt Fuji model. Despite the simplicity of this model, it captures the features of the experimental landscapes remarkably well. (paper)

  19. Qualitative Case Study Research as Empirical Inquiry

    Science.gov (United States)

    Ellinger, Andrea D.; McWhorter, Rochell

    2016-01-01

    This article introduces the concept of qualitative case study research as empirical inquiry. It defines and distinguishes what a case study is, the purposes, intentions, and types of case studies. It then describes how to determine if a qualitative case study is the preferred approach for conducting research. It overviews the essential steps in…

  20. The problem analysis for empirical studies

    NARCIS (Netherlands)

    Groenland, E.A.G.

    2014-01-01

    This article proposes a systematic methodology for the development of a problem analysis for cross-sectional, empirical research. This methodology is referred to as the 'Annabel approach'. It is suitable both for academic studies and applied (business) studies. In addition it can be used for both

  1. Empirical questions for collective-behaviour modelling

    Indian Academy of Sciences (India)

    The collective behaviour of groups of social animals has been an active topic of study ... Models have been successful at reproducing qualitative features of ... quantitative and detailed empirical results for a range of animal systems. ... standard method [23], the redundant information recorded by the cameras can be used to.

  2. Synthetic and Empirical Capsicum Annuum Image Dataset

    NARCIS (Netherlands)

    Barth, R.

    2016-01-01

    This dataset consists of per-pixel annotated synthetic (10500) and empirical images (50) of Capsicum annuum, also known as sweet or bell pepper, situated in a commercial greenhouse. Furthermore, the source models to generate the synthetic images are included. The aim of the datasets are to

  3. An Empirical Investigation into Programming Language Syntax

    Science.gov (United States)

    Stefik, Andreas; Siebert, Susanna

    2013-01-01

    Recent studies in the literature have shown that syntax remains a significant barrier to novice computer science students in the field. While this syntax barrier is known to exist, whether and how it varies across programming languages has not been carefully investigated. For this article, we conducted four empirical studies on programming…

  4. Self-Published Books: An Empirical "Snapshot"

    Science.gov (United States)

    Bradley, Jana; Fulton, Bruce; Helm, Marlene

    2012-01-01

    The number of books published by authors using fee-based publication services, such as Lulu and AuthorHouse, is overtaking the number of books published by mainstream publishers, according to Bowker's 2009 annual data. Little empirical research exists on self-published books. This article presents the results of an investigation of a random sample…

  5. Empirical Differential Balancing for Nonlinear Systems

    NARCIS (Netherlands)

    Kawano, Yu; Scherpen, Jacquelien M.A.; Dochain, Denis; Henrion, Didier; Peaucelle, Dimitri

    In this paper, we consider empirical balancing of nonlinear systems by using its prolonged system, which consists of the original nonlinear system and its variational system. For the prolonged system, we define differential reachability and observability Gramians, which are matrix valued functions

  6. Multiscale empirical interpolation for solving nonlinear PDEs

    KAUST Repository

    Calo, Victor M.

    2014-12-01

    In this paper, we propose a multiscale empirical interpolation method for solving nonlinear multiscale partial differential equations. The proposed method combines empirical interpolation techniques and local multiscale methods, such as the Generalized Multiscale Finite Element Method (GMsFEM). To solve nonlinear equations, the GMsFEM is used to represent the solution on a coarse grid with multiscale basis functions computed offline. Computing the GMsFEM solution involves calculating the system residuals and Jacobians on the fine grid. We use empirical interpolation concepts to evaluate these residuals and Jacobians of the multiscale system with a computational cost which is proportional to the size of the coarse-scale problem rather than the fully-resolved fine scale one. The empirical interpolation method uses basis functions which are built by sampling the nonlinear function we want to approximate a limited number of times. The coefficients needed for this approximation are computed in the offline stage by inverting an inexpensive linear system. The proposed multiscale empirical interpolation techniques: (1) divide computing the nonlinear function into coarse regions; (2) evaluate contributions of nonlinear functions in each coarse region taking advantage of a reduced-order representation of the solution; and (3) introduce multiscale proper-orthogonal-decomposition techniques to find appropriate interpolation vectors. We demonstrate the effectiveness of the proposed methods on several nonlinear multiscale PDEs that are solved with Newton\\'s methods and fully-implicit time marching schemes. Our numerical results show that the proposed methods provide a robust framework for solving nonlinear multiscale PDEs on a coarse grid with bounded error and significant computational cost reduction.

  7. Equilibrium calculations and mode analysis

    International Nuclear Information System (INIS)

    Herrnegger, F.

    1987-01-01

    The STEP asymptotic stellarator expansion procedure was used to study the MHD equilibrium and stability properties of stellarator configurations without longitudinal net-current, which also apply to advanced stellarators. The effects of toroidal curvature and magnetic well, and the Shafranov shift were investigated. A classification of unstable modes in toroidal stellarators is given. For WVII-A coil-field configurations having a β value of 1% and a parabolic pressure profile, no free-boundary modes are found. This agrees with the experimental fact that unstable behavior of the plasma column is not observed for this parameter range. So a theoretical β-limit for stability against ideal MHD modes can be estimated by mode analysis for the WVII-A device

  8. Tapping mode microwave impedance microscopy

    KAUST Repository

    Lai, K.; Kundhikanjana, W.; Peng, H.; Cui, Y.; Kelly, M. A.; Shen, Z. X.

    2009-01-01

    We report tapping mode microwave impedance imaging based on atomic force microscope platforms. The shielded cantilever probe is critical to localize the tip-sample interaction near the tip apex. The modulated tip-sample impedance can be accurately

  9. Common mode and coupled failure

    International Nuclear Information System (INIS)

    Taylor, J.R.

    1975-10-01

    Based on examples and data from Abnormal Occurence Reports for nuclear reactors, a classification of common mode or coupled failures is given, and some simple statistical models are investigated. (author)

  10. Amplitude damping of vortex modes

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2010-09-01

    Full Text Available An interferometer, mimicking an amplitude damping channel for vortex modes, is presented. Experimentally the action of the channel is in good agreement with that predicted theoretically. Since we can characterize the action of the channel on orbital...

  11. Peeling mode relaxation ELM model

    International Nuclear Information System (INIS)

    Gimblett, C. G.

    2006-01-01

    This paper discusses an approach to modelling Edge Localised Modes (ELMs) in which toroidal peeling modes are envisaged to initiate a constrained relaxation of the tokamak outer region plasma. Relaxation produces both a flattened edge current profile (which tends to further destabilise a peeling mode), and a plasma-vacuum negative current sheet which has a counteracting stabilising influence; the balance that is struck between these two effects determines the radial extent (rE) of the ELM relaxed region. The model is sensitive to the precise position of the mode rational surfaces to the plasma surface and hence there is a 'deterministic scatter' in the results that has an accord with experimental data. The toroidal peeling stability criterion involves the edge pressure, and using this in conjunction with predictions of rE allows us to evaluate the ELM energy losses and compare with experiment. Predictions of trends with the edge safety factor and collisionality are also made

  12. Fiber cavities with integrated mode matching optics.

    Science.gov (United States)

    Gulati, Gurpreet Kaur; Takahashi, Hiroki; Podoliak, Nina; Horak, Peter; Keller, Matthias

    2017-07-17

    In fiber based Fabry-Pérot Cavities (FFPCs), limited spatial mode matching between the cavity mode and input/output modes has been the main hindrance for many applications. We have demonstrated a versatile mode matching method for FFPCs. Our novel design employs an assembly of a graded-index and large core multimode fiber directly spliced to a single mode fiber. This all-fiber assembly transforms the propagating mode of the single mode fiber to match with the mode of a FFPC. As a result, we have measured a mode matching of 90% for a cavity length of ~400 μm. This is a significant improvement compared to conventional FFPCs coupled with just a single mode fiber, especially at long cavity lengths. Adjusting the parameters of the assembly, the fundamental cavity mode can be matched with the mode of almost any single mode fiber, making this approach highly versatile and integrable.

  13. Evidence of the wobbling mode

    International Nuclear Information System (INIS)

    Odegaard, S.W.; Tjoem, P.O.; Hagemann, G.B.; Jensen, D.R.; Bergstroem, M.; Herskind, B.; Sletten, G.; Toermaenen, S.; Wilson, J.N.; Hamamoto, I.; Spohr, K.; Huebel, H.; Goergen, A.; Schoenwasser, G.; Bracco, A.; Leoni, S.; Maj, A.; Petrache, C.M.; Bednarczyk, P.; Curien, D.

    2002-01-01

    The wobbling mode is a direct consequence of rotational motion of a triaxial body. The wobbling degree of freedom introduces sequences of bands with increasing number of wobbling quanta and a characteristic ΔI=1 decay pattern between the bands in competition with the in-band decay. A favorable candidate for establishing this exotic excitation mode is found for the first time in one of the Lu-isotopes for which stable triaxial superdeformed shapes are expected

  14. Structural system identification based on variational mode decomposition

    Science.gov (United States)

    Bagheri, Abdollah; Ozbulut, Osman E.; Harris, Devin K.

    2018-03-01

    In this paper, a new structural identification method is proposed to identify the modal properties of engineering structures based on dynamic response decomposition using the variational mode decomposition (VMD). The VMD approach is a decomposition algorithm that has been developed as a means to overcome some of the drawbacks and limitations of the empirical mode decomposition method. The VMD-based modal identification algorithm decomposes the acceleration signal into a series of distinct modal responses and their respective center frequencies, such that when combined their cumulative modal responses reproduce the original acceleration response. The decaying amplitude of the extracted modal responses is then used to identify the modal damping ratios using a linear fitting function on modal response data. Finally, after extracting modal responses from available sensors, the mode shape vector for each of the decomposed modes in the system is identified from all obtained modal response data. To demonstrate the efficiency of the algorithm, a series of numerical, laboratory, and field case studies were evaluated. The laboratory case study utilized the vibration response of a three-story shear frame, whereas the field study leveraged the ambient vibration response of a pedestrian bridge to characterize the modal properties of the structure. The modal properties of the shear frame were computed using analytical approach for a comparison with the experimental modal frequencies. Results from these case studies demonstrated that the proposed method is efficient and accurate in identifying modal data of the structures.

  15. Packaged mode multiplexer based on silicon photonics

    NARCIS (Netherlands)

    Chen, H.; Koonen, A.M.J.; Snyder, B.; Raz, O.; Boom, van den H.P.A.; Chen, X.

    2012-01-01

    A silicon photonics based mode multiplexer is proposed. Four chirped grating couplers structure can support all 6 channels in a two-mode fiber and realize LP01 and LP11 mode selective exciting. The packaged device is tested.

  16. Challenges in higher order mode Raman amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Nielsen, Kristian; Friis, Søren Michael Mørk

    2015-01-01

    A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed......A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed...

  17. Empirical Bayesian inference and model uncertainty

    International Nuclear Information System (INIS)

    Poern, K.

    1994-01-01

    This paper presents a hierarchical or multistage empirical Bayesian approach for the estimation of uncertainty concerning the intensity of a homogeneous Poisson process. A class of contaminated gamma distributions is considered to describe the uncertainty concerning the intensity. These distributions in turn are defined through a set of secondary parameters, the knowledge of which is also described and updated via Bayes formula. This two-stage Bayesian approach is an example where the modeling uncertainty is treated in a comprehensive way. Each contaminated gamma distributions, represented by a point in the 3D space of secondary parameters, can be considered as a specific model of the uncertainty about the Poisson intensity. Then, by the empirical Bayesian method each individual model is assigned a posterior probability

  18. Porphyry of Russian Empires in Paris

    Science.gov (United States)

    Bulakh, Andrey

    2014-05-01

    Porphyry of Russian Empires in Paris A. G. Bulakh (St Petersburg State University, Russia) So called "Schokhan porphyry" from Lake Onega, Russia, belongs surely to stones of World cultural heritage. One can see this "porphyry" at facades of a lovely palace of Pavel I and in pedestal of the monument after Nicolas I in St Petersburg. There are many other cases of using this stone in Russia. In Paris, sarcophagus of Napoleon I Bonaparte is constructed of blocks of this stone. Really, it is Proterozoic quartzite. Geology situation, petrography and mineralogical characteristic will be reported too. Comparison with antique porphyre from the Egyptian Province of the Roma Empire is given. References: 1) A.G.Bulakh, N.B.Abakumova, J.V.Romanovsky. St Petersburg: a History in Stone. 2010. Print House of St Petersburg State University. 173 p.

  19. Two-mode PLC-based mode multi/demultiplexer for mode and wavelength division multiplexed transmission.

    Science.gov (United States)

    Hanzawa, Nobutomo; Saitoh, Kuimasa; Sakamoto, Taiji; Matsui, Takashi; Tsujikawa, Kyozo; Koshiba, Masanori; Yamamoto, Fumihiko

    2013-11-04

    We proposed a PLC-based mode multi/demultiplexer (MUX/DEMUX) with an asymmetric parallel waveguide for mode division multiplexed (MDM) transmission. The mode MUX/DEMUX including a mode conversion function with an asymmetric parallel waveguide can be realized by matching the effective indices of the LP(01) and LP(11) modes of two waveguides. We report the design of a mode MUX/DEMUX that can support C-band WDM-MDM transmission. The fabricated mode MUX/DEMUX realized a low insertion loss of less than 1.3 dB and high a mode extinction ratio that exceeded 15 dB. We used the fabricated mode MUX/DEMUX to achieve a successful 2 mode x 4 wavelength x 10 Gbps transmission over a 9 km two-mode fiber with a penalty of less than 1 dB.

  20. Surface Passivation in Empirical Tight Binding

    OpenAIRE

    He, Yu; Tan, Yaohua; Jiang, Zhengping; Povolotskyi, Michael; Klimeck, Gerhard; Kubis, Tillmann

    2015-01-01

    Empirical Tight Binding (TB) methods are widely used in atomistic device simulations. Existing TB methods to passivate dangling bonds fall into two categories: 1) Method that explicitly includes passivation atoms is limited to passivation with atoms and small molecules only. 2) Method that implicitly incorporates passivation does not distinguish passivation atom types. This work introduces an implicit passivation method that is applicable to any passivation scenario with appropriate parameter...

  1. Empirically Examining Prostitution through a Feminist Perspective

    OpenAIRE

    Child, Shyann

    2009-01-01

    The purpose of this thesis is to empirically explore prostitution through a feminist perspective. Several background factors are explored on a small sample of women in the northeastern United States. Some of these women have been involved in an act of prostitution in their lifetime; some have not. This research will add to the body of knowledge on prostitution, as well as highlight the unique experiences of women. The goal is to understand whether or not these life experiences have had a h...

  2. Theoretical and Empirical Descriptions of Thermospheric Density

    Science.gov (United States)

    Solomon, S. C.; Qian, L.

    2004-12-01

    The longest-term and most accurate overall description the density of the upper thermosphere is provided by analysis of change in the ephemeris of Earth-orbiting satellites. Empirical models of the thermosphere developed in part from these measurements can do a reasonable job of describing thermospheric properties on a climatological basis, but the promise of first-principles global general circulation models of the coupled thermosphere/ionosphere system is that a true high-resolution, predictive capability may ultimately be developed for thermospheric density. However, several issues are encountered when attempting to tune such models so that they accurately represent absolute densities as a function of altitude, and their changes on solar-rotational and solar-cycle time scales. Among these are the crucial ones of getting the heating rates (from both solar and auroral sources) right, getting the cooling rates right, and establishing the appropriate boundary conditions. However, there are several ancillary issues as well, such as the problem of registering a pressure-coordinate model onto an altitude scale, and dealing with possible departures from hydrostatic equilibrium in empirical models. Thus, tuning a theoretical model to match empirical climatology may be difficult, even in the absence of high temporal or spatial variation of the energy sources. We will discuss some of the challenges involved, and show comparisons of simulations using the NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) to empirical model estimates of neutral thermosphere density and temperature. We will also show some recent simulations using measured solar irradiance from the TIMED/SEE instrument as input to the TIE-GCM.

  3. Insurability of Cyber Risk: An Empirical Analysis

    OpenAIRE

    Biener, Christian; Eling, Martin; Wirfs, Jan Hendrik

    2015-01-01

    This paper discusses the adequacy of insurance for managing cyber risk. To this end, we extract 994 cases of cyber losses from an operational risk database and analyse their statistical properties. Based on the empirical results and recent literature, we investigate the insurability of cyber risk by systematically reviewing the set of criteria introduced by Berliner (1982). Our findings emphasise the distinct characteristics of cyber risks compared with other operational risks and bring to li...

  4. Conducting empirical research in virtual worlds

    OpenAIRE

    Minocha, Shailey

    2011-01-01

    We will focus on the following aspects of conducting empirical research in virtual worlds: the toolbox of techniques for data collection; selection of technique(s) for the research questions; tips on how the techniques need to be adapted for conducting research in virtual worlds; guidance for developing research materials such as the consent form, project summary sheet, and how to address the possible concerns of an institution’s ethics committee who may not be familiar with the avatar-based ...

  5. Empirical solar/stellar cycle simulations

    Directory of Open Access Journals (Sweden)

    Santos Ângela R. G.

    2015-01-01

    Full Text Available As a result of the magnetic cycle, the properties of the solar oscillations vary periodically. With the recent discovery of manifestations of activity cycles in the seismic data of other stars, the understanding of the different contributions to such variations becomes even more important. With this in mind, we built an empirical parameterised model able to reproduce the properties of the sunspot cycle. The resulting simulations can be used to estimate the magnetic-induced frequency shifts.

  6. The empirical turn in international legal scholarship

    Directory of Open Access Journals (Sweden)

    Gregory Shaffer

    2015-07-01

    Full Text Available This article presents and assesses a new wave of em- pirical research on international law. Recent scholar- ship has moved away from theoretical debates over whether international law “matters,” and focuses in- stead on exploring the conditions under which inter- national law is created and produces effects. As this empirical research program has matured, it has al- lowed for new, midlevel theorizing that we call “conditional international law theory”. 

  7. Compassion: An Evolutionary Analysis and Empirical Review

    OpenAIRE

    Goetz, Jennifer L.; Keltner, Dacher; Simon-Thomas, Emiliana

    2010-01-01

    What is compassion? And how did it evolve? In this review, we integrate three evolutionary arguments that converge on the hypothesis that compassion evolved as a distinct affective experience whose primary function is to facilitate cooperation and protection of the weak and those who suffer. Our empirical review reveals compassion to have distinct appraisal processes attuned to undeserved suffering, distinct signaling behavior related to caregiving patterns of touch, posture, and vocalization...

  8. Services outsourcing and innovation: an empirical investigation

    OpenAIRE

    Görg, Holger; Hanley, Aoife

    2009-01-01

    We provide a comprehensive empirical analysis of the links between international services outsourcing, domestic outsourcing, profits and innovation using plant level data. We find a positive effect of international outsourcing of services on innovative activity at the plant level. Such a positive effect can also be observed for domestic outsourcing of services, but the magnitude is smaller. This makes intuitive sense, as international outsourcing allows more scope for exploiting international...

  9. Tearing modes in toroidal geometry

    International Nuclear Information System (INIS)

    Connor, J.W.; Cowley, S.C.; Hastie, R.J.; Hender, T.C.; Hood, A.; Martin, T.J.

    1988-01-01

    The separation of the cylindrical tearing mode stability problem into a resistive resonant layer calculation and an external marginal ideal magnetohydrodynamic (MHD) calculation (Δ' calculation) is generalized to axisymmetric toroidal geometry. The general structure of this separation is analyzed and the marginal ideal MHD information (the toroidal generalization of Δ') required to discuss stability is isolated. This can then, in principle, be combined with relevant resonant layer calculations to determine tearing mode growth rates in realistic situations. Two examples are given: the first is an analytic treatment of toroidally coupled (m = 1, n = 1) and (m = 2, n = 1) tearing modes in a large aspect ratio torus; the second, a numerical treatment of the toroidal coupling of three tearing modes through finite pressure effects in a large aspect ratio torus. In addition, the use of a coupling integral approach for determining the stability of coupled tearing modes is discussed. Finally, the possibility of using initial value resistive MHD codes in realistic toroidal geometry to determine the necessary information from the ideal MHD marginal solution is discussed

  10. Empirical methods for estimating future climatic conditions

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    Applying the empirical approach permits the derivation of estimates of the future climate that are nearly independent of conclusions based on theoretical (model) estimates. This creates an opportunity to compare these results with those derived from the model simulations of the forthcoming changes in climate, thus increasing confidence in areas of agreement and focusing research attention on areas of disagreements. The premise underlying this approach for predicting anthropogenic climate change is based on associating the conditions of the climatic optimums of the Holocene, Eemian, and Pliocene with corresponding stages of the projected increase of mean global surface air temperature. Provided that certain assumptions are fulfilled in matching the value of the increased mean temperature for a certain epoch with the model-projected change in global mean temperature in the future, the empirical approach suggests that relationships leading to the regional variations in air temperature and other meteorological elements could be deduced and interpreted based on use of empirical data describing climatic conditions for past warm epochs. Considerable care must be taken, of course, in making use of these spatial relationships, especially in accounting for possible large-scale differences that might, in some cases, result from different factors contributing to past climate changes than future changes and, in other cases, might result from the possible influences of changes in orography and geography on regional climatic conditions over time

  11. Comparison of ITER performance predicted by semi-empirical and theory-based transport models

    International Nuclear Information System (INIS)

    Mukhovatov, V.; Shimomura, Y.; Polevoi, A.

    2003-01-01

    The values of Q=(fusion power)/(auxiliary heating power) predicted for ITER by three different methods, i.e., transport model based on empirical confinement scaling, dimensionless scaling technique, and theory-based transport models are compared. The energy confinement time given by the ITERH-98(y,2) scaling for an inductive scenario with plasma current of 15 MA and plasma density 15% below the Greenwald value is 3.6 s with one technical standard deviation of ±14%. These data are translated into a Q interval of [7-13] at the auxiliary heating power P aux = 40 MW and [7-28] at the minimum heating power satisfying a good confinement ELMy H-mode. Predictions of dimensionless scalings and theory-based transport models such as Weiland, MMM and IFS/PPPL overlap with the empirical scaling predictions within the margins of uncertainty. (author)

  12. From Discovery to Justification: Outline of an Ideal Research Program in Empirical Psychology

    Science.gov (United States)

    Witte, Erich H.; Zenker, Frank

    2017-01-01

    The gold standard for an empirical science is the replicability of its research results. But the estimated average replicability rate of key-effects that top-tier psychology journals report falls between 36 and 39% (objective vs. subjective rate; Open Science Collaboration, 2015). So the standard mode of applying null-hypothesis significance testing (NHST) fails to adequately separate stable from random effects. Therefore, NHST does not fully convince as a statistical inference strategy. We argue that the replicability crisis is “home-made” because more sophisticated strategies can deliver results the successful replication of which is sufficiently probable. Thus, we can overcome the replicability crisis by integrating empirical results into genuine research programs. Instead of continuing to narrowly evaluate only the stability of data against random fluctuations (discovery context), such programs evaluate rival hypotheses against stable data (justification context). PMID:29163256

  13. Space evolution model and empirical analysis of an urban public transport network

    Science.gov (United States)

    Sui, Yi; Shao, Feng-jing; Sun, Ren-cheng; Li, Shu-jing

    2012-07-01

    This study explores the space evolution of an urban public transport network, using empirical evidence and a simulation model validated on that data. Public transport patterns primarily depend on traffic spatial-distribution, demands of passengers and expected utility of investors. Evolution is an iterative process of satisfying the needs of passengers and investors based on a given traffic spatial-distribution. The temporal change of urban public transport network is evaluated both using topological measures and spatial ones. The simulation model is validated using empirical data from nine big cities in China. Statistical analyses on topological and spatial attributes suggest that an evolution network with traffic demands characterized by power-law numerical values which distribute in a mode of concentric circles tallies well with these nine cities.

  14. An Empirical Validation of Building Simulation Software for Modelling of Double-Skin Facade (DSF)

    DEFF Research Database (Denmark)

    Larsen, Olena Kalyanova; Heiselberg, Per; Felsmann, Clemens

    2009-01-01

    buildings, but their accuracy might be limited in cases with DSFs because of the complexity of the heat and mass transfer processes within the DSF. To address this problem, an empirical validation of building models with DSF, performed with various building simulation tools (ESP-r, IDA ICE 3.0, VA114......Double-skin facade (DSF) buildings are being built as an attractive, innovative and energy efficient solution. Nowadays, several design tools are used for assessment of thermal and energy performance of DSF buildings. Existing design tools are well-suited for performance assessment of conventional......, TRNSYS-TUD and BSim) was carried out in the framework of IEA SHC Task 34 /ECBCS Annex 43 "Testing and Validation of Building Energy Simulation Tools". The experimental data for the validation was gathered in a full-scale outdoor test facility. The empirical data sets comprise the key-functioning modes...

  15. Improved inland water levels from SAR altimetry using novel empirical and physical retrackers

    DEFF Research Database (Denmark)

    Villadsen, Heidi; Deng, Xiaoli; Andersen, Ole Baltazar

    2016-01-01

    with in situdata in Lake Vänern and Lake Okeechobee are in the order of 2–5 cm for well-behaved waveforms. Combining the physical and empirical retrackers did not offer significantly improved mean track standarddeviations or RMSEs. Based on these studies, it is suggested that future SAR derived water levels......Satellite altimetry has proven a valuable resource of information on river and lake levels where in situ data are sparse or non-existent. In this study several new methods for obtaining stable inland water levels from CryoSat-2 Synthetic Aperture Radar (SAR) altimetry are presented and evaluated....... In addition, the possible benefits from combining physical and empirical retrackers are investigated.The retracking methods evaluated in this paper include the physical SAR Altimetry MOde Studies andApplications (SAMOSA3) model, a traditional subwaveform threshold retracker, the proposed Multiple...

  16. Whole-body cryotherapy: empirical evidence and theoretical perspectives.

    Science.gov (United States)

    Bleakley, Chris M; Bieuzen, François; Davison, Gareth W; Costello, Joseph T

    2014-01-01

    Whole-body cryotherapy (WBC) involves short exposures to air temperatures below -100°C. WBC is increasingly accessible to athletes, and is purported to enhance recovery after exercise and facilitate rehabilitation postinjury. Our objective was to review the efficacy and effectiveness of WBC using empirical evidence from controlled trials. We found ten relevant reports; the majority were based on small numbers of active athletes aged less than 35 years. Although WBC produces a large temperature gradient for tissue cooling, the relatively poor thermal conductivity of air prevents significant subcutaneous and core body cooling. There is weak evidence from controlled studies that WBC enhances antioxidant capacity and parasympathetic reactivation, and alters inflammatory pathways relevant to sports recovery. A series of small randomized studies found WBC offers improvements in subjective recovery and muscle soreness following metabolic or mechanical overload, but little benefit towards functional recovery. There is evidence from one study only that WBC may assist rehabilitation for adhesive capsulitis of the shoulder. There were no adverse events associated with WBC; however, studies did not seem to undertake active surveillance of predefined adverse events. Until further research is available, athletes should remain cognizant that less expensive modes of cryotherapy, such as local ice-pack application or cold-water immersion, offer comparable physiological and clinical effects to WBC.

  17. "Heart-cut" bidimensional achiral-chiral liquid chromatography applied to the evaluation of stereoselective metabolism, in vivo biological activity and brain response to chiral drug candidates targeting the central nervous system.

    Science.gov (United States)

    Battisti, Umberto M; Citti, Cinzia; Larini, Martina; Ciccarella, Giuseppe; Stasiak, Natalia; Troisi, Luigino; Braghiroli, Daniela; Parenti, Carlo; Zoli, Michele; Cannazza, Giuseppe

    2016-04-22

    A "heart-cut" two-dimensional achiral-chiral liquid chromatography triple-quadrupole mass spectrometry method (LC-LC-MS/MS) was developed and coupled to in vivo cerebral microdialysis to evaluate the brain response to the chiral compound (±)-7-chloro-5-(3-furanyl)-3-methyl-3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxide ((±)-1), a potent positive allosteric modulator (PAM) of AMPA receptor. The method was successfully employed to evaluate also its stereoselective metabolism and in vitro biological activity. In particular, the LC achiral method developed, employs a pentafluorinated silica based column (Discovery HS-F5) to separate dopamine, acetylcholine, serotonin, (±)-1 and its two hepatic metabolites. In the "heart-cut" two-dimension achiral-chiral configuration, (±)-1 and (±)-1-d4 eluted from the achiral column (1st dimension), were transferred to a polysaccharide-based chiral column (2nd dimension, Chiralcel OD-RH) by using an automatic six-port valve. Single enantiomers of (±)-1 were separated and detected using electrospray positive ionization mode and quantified in selected reaction monitoring mode. The method was validated and showed good performance in terms of linearity, accuracy and precision. The new method employed showed several possible applications in the evaluation of: (a) brain response to neuroactive compounds by measuring variations in the brain extracellular levels of selected neurotransmitters and other biomarkers; (b) blood brain barrier penetration of drug candidates by measuring the free concentration of the drug in selected brain areas; (c) the presence of drug metabolites in the brain extracellular fluid that could prove very useful during drug discovery; (d) a possible stereoselective metabolization or blood brain barrier stereoselective crossing of chiral drugs. Finally, compared to the methods reported in the literature, this technique avoids the necessity of euthanizing an animal at each time point to measure drug

  18. Tapping mode microwave impedance microscopy

    KAUST Repository

    Lai, K.

    2009-01-01

    We report tapping mode microwave impedance imaging based on atomic force microscope platforms. The shielded cantilever probe is critical to localize the tip-sample interaction near the tip apex. The modulated tip-sample impedance can be accurately simulated by the finite-element analysis and the result agrees quantitatively to the experimental data on a series of thin-film dielectric samples. The tapping mode microwave imaging is also superior to the contact mode in that the thermal drift in a long time scale is totally eliminated and an absolute measurement on the dielectric properties is possible. We demonstrated tapping images on working nanodevices, and the data are consistent with the transport results. © 2009 American Institute of Physics.

  19. Reconfigurable Mixed Mode Universal Filter

    Directory of Open Access Journals (Sweden)

    Neelofer Afzal

    2014-01-01

    Full Text Available This paper presents a novel mixed mode universal filter configuration capable of working in voltage and transimpedance mode. The proposed single filter configuration can be reconfigured digitally to realize all the five second order filter functions (types at single output port. Other salient features of proposed configuration include independently programmable filter parameters, full cascadability, and low sensitivity figure. However, all these features are provided at the cost of quite large number of active elements. It needs three digitally programmable current feedback amplifiers and three digitally programmable current conveyors. Use of six active elements is justified by introducing three additional reduced hardware mixed mode universal filter configurations and its comparison with reported filters.

  20. Quasiadiabatic modes from viscous inhomogeneities

    CERN Document Server

    Giovannini, Massimo

    2016-04-20

    The viscous inhomogeneities of a relativistic plasma determine a further class of entropic modes whose amplitude must be sufficiently small since curvature perturbations are observed to be predominantly adiabatic and Gaussian over large scales. When the viscous coefficients only depend on the energy density of the fluid the corresponding curvature fluctuations are shown to be almost adiabatic. After addressing the problem in a gauge-invariant perturbative expansion, the same analysis is repeated at a non-perturbative level by investigating the nonlinear curvature inhomogeneities induced by the spatial variation of the viscous coefficients. It is demonstrated that the quasiadiabatic modes are suppressed in comparison with a bona fide adiabatic solution. Because of its anomalously large tensor to scalar ratio the quasiadiabatic mode cannot be a substitute for the conventional adiabatic paradigm so that, ultimately, the present findings seems to exclude the possibility of a successful accelerated dynamics solely...

  1. Macroscopic (and microscopic massless modes

    Directory of Open Access Journals (Sweden)

    Michael C. Abbott

    2015-05-01

    Full Text Available We study certain spinning strings exploring the flat directions of AdS3×S3×S3×S1, the massless sector cousins of su(2 and sl(2 sector spinning strings. We describe these, and their vibrational modes, using the D(2,1;α2 algebraic curve. By exploiting a discrete symmetry of this structure which reverses the direction of motion on the spheres, and alters the masses of the fermionic modes s→κ−s, we find out how to treat the massless fermions which were previously missing from this formalism. We show that folded strings behave as a special case of circular strings, in a sense which includes their mode frequencies, and we are able to recover this fact in the worldsheet formalism. We use these frequencies to calculate one-loop corrections to the energy, with a version of the Beisert–Tseytlin resummation.

  2. Empirical research in medical ethics: How conceptual accounts on normative-empirical collaboration may improve research practice

    Science.gov (United States)

    2012-01-01

    Background The methodology of medical ethics during the last few decades has shifted from a predominant use of normative-philosophical analyses to an increasing involvement of empirical methods. The articles which have been published in the course of this so-called 'empirical turn' can be divided into conceptual accounts of empirical-normative collaboration and studies which use socio-empirical methods to investigate ethically relevant issues in concrete social contexts. Discussion A considered reference to normative research questions can be expected from good quality empirical research in medical ethics. However, a significant proportion of empirical studies currently published in medical ethics lacks such linkage between the empirical research and the normative analysis. In the first part of this paper, we will outline two typical shortcomings of empirical studies in medical ethics with regard to a link between normative questions and empirical data: (1) The complete lack of normative analysis, and (2) cryptonormativity and a missing account with regard to the relationship between 'is' and 'ought' statements. Subsequently, two selected concepts of empirical-normative collaboration will be presented and how these concepts may contribute to improve the linkage between normative and empirical aspects of empirical research in medical ethics will be demonstrated. Based on our analysis, as well as our own practical experience with empirical research in medical ethics, we conclude with a sketch of concrete suggestions for the conduct of empirical research in medical ethics. Summary High quality empirical research in medical ethics is in need of a considered reference to normative analysis. In this paper, we demonstrate how conceptual approaches of empirical-normative collaboration can enhance empirical research in medical ethics with regard to the link between empirical research and normative analysis. PMID:22500496

  3. Stability or instability in avoidant personality disorder:Mode fluctuations within schema therapy sessions.

    Science.gov (United States)

    Peled, Ofer; Bar-Kalifa, Eran; Rafaeli, Eshkol

    2017-12-01

    Avoidant personality disorder (APD) is among the most prevalent personality disorders, but has received relatively little empirical attention. This study aims to characterize the frequency, intensity, and fluctuation patterns seen in the modes (self-states) of APD clients over the course of schema therapy (ST), a psychotherapy approach developed especially for personality disorders. The newly-developed client mode rating scale (CMRS) was used to code every 5-min segment (n = 645) of 60 ST sessions. Each segment was coded by two independent raters, achieving adequate reliability. The avoidant/detached mode was present in 74% of therapy segments and was the most intense and unstable mode; the vulnerable child mode was present in 58% of segments and was the second most intense and unstable mode; the dysfunctional parent mode was present in 40% of segments, and was the third most intense and unstable mode; the over-compensator, compliant-surrenderer, and healthy adult modes were present in around 33% of segments, but the healthy adult mode was significantly more stable than all others. Although 645 segments were coded, they were drawn from only 15 APD clients with no control group. Further studies are needed to established specificity to APD. This study demonstrates the utility of the mode concept as a lexicon for capturing personality states and their instability. It highlights the use of in-session segment-by-segment ratings to assess client change within psychotherapy. Although DSM5 fails to address instability as a criterion for avoidant personality disorder, the APD clients in the current study were characterized by considerable mode instability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Physics of resistive wall modes

    International Nuclear Information System (INIS)

    Igochine, V.

    2012-01-01

    The advanced tokamak regime is a promising candidate for steady-state tokamak operation which is desirable for a fusion reactor. This regime is characterized by a high bootstrap current fraction and a flat or reversed safety factor profile, which leads to operation close to the pressure limit. At this limit, an external kink mode becomes unstable. This external kink is converted into the slowly growing resistive wall mode (RWM) by the presence of a conducting wall. Reduction of the growth rate allows one to act on the mode and to stabilize it. There are two main factors which determine the stability of the RWM. The first factor comes from external magnetic perturbations (error fields, resistive wall, feedback coils, etc). This part of RWM physics is the same for tokamaks and reversed field pinch configurations. The physics of this interaction is relatively well understood and based on classical electrodynamics. The second ingredient of RWM physics is the interaction of the mode with plasma flow and fast particles. These interactions are particularly important for tokamaks, which have higher plasma flow and stronger trapped particle effects. The influence of the fast particles will also be increasingly more important in ITER and DEMO which will have a large fraction of fusion born alpha particles. These interactions have kinetic origins which make the computations challenging since not only particles influence the mode, but also the mode acts on the particles. Correct prediction of the ‘plasma–RWM’ interaction is an important ingredient which has to be combined with external field's influence (resistive wall, error fields and feedback) to make reliable predictions for RWM behaviour in tokamaks. All these issues are reviewed in this paper. (special topic)

  5. Renormalized modes in cuprate superconductors

    Science.gov (United States)

    Gupta, Anushri; Kumari, Anita; Verma, Sanjeev K.; Indu, B. D.

    2018-04-01

    The renormalized mode frequencies are obtained with the help of quantum dynamical approach of many body phonon Green's function technique via a general Hamiltonian (excluding BCS Hamiltonian) including the effects of phonons and electrons, anharmonicities and electron-phonon interactions. The numerical estimates have been carried out to study the renormalized mode frequency of high temperature cuprate superconductor (HTS) YBa2Cu3O7-δ using modified Born-Mayer-Huggins interaction potential (MBMHP) best applicable to study the dynamical properties of all HTS.

  6. Transformation and Modes of Production

    DEFF Research Database (Denmark)

    Høst, Jeppe Engset

    2015-01-01

    modes of production and examine the ways of life that are enabled by the two modes of production. The central questions are around how market-based fisheries management transforms the principal preconditions for the self-employed fishers; and, in turn, why capitalist organized large-scale fisheries......The introduction of private and individual transferable quotas is widely considered to have a negative impact on small- and medium-sized fishing operations. In this chapter, I set out to explore this in a theoretical manner. I discuss the differences in the fishing operations as two contrasting...

  7. Soft mode of lead zirconate

    International Nuclear Information System (INIS)

    Pan'ko, G.F.; Prisedskij, V.V.; Klimov, V.V.

    1983-01-01

    Anisotropic diffusional scattering of electrons on PbZrO 3 crystal in the temperature range of phase transition has been recorded. As a result of its analysis it has been established that in lead zirconate the rotational vibrational mode G 25 plays the role of soft mode. The experiment is carried out using PbZrO 3 monocrystals in translucent electron microscope EhM-200, operating in the regime of microdiffraction at accelerating voltage of 150 kV and beam current 50 μA; sample preparation is realized using the method of shearing and fragmentation

  8. A synthesis of empirical plant dispersal kernels

    Czech Academy of Sciences Publication Activity Database

    Bullock, J. M.; González, L. M.; Tamme, R.; Götzenberger, Lars; White, S. M.; Pärtel, M.; Hooftman, D. A. P.

    2017-01-01

    Roč. 105, č. 1 (2017), s. 6-19 ISSN 0022-0477 Institutional support: RVO:67985939 Keywords : dispersal kernel * dispersal mode * probability density function Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 5.813, year: 2016

  9. AN EMPIRICAL ASSESSMENT OF THE RELATIONSHIP OF

    African Journals Online (AJOL)

    ETIWISTIC

    2013-04-29

    Apr 29, 2013 ... 7 (2), Serial No. ... adopted by counsellors in treating students with truant habits, ... Therefore, there is need to find out the most effective counselling mode to ... professional counsellor with one person only (i.e. individual ...

  10. Selection Bias in Educational Transition Models: Theory and Empirical Evidence

    DEFF Research Database (Denmark)

    Holm, Anders; Jæger, Mads

    variables. This paper, first, explains theoretically how selection on unobserved variables leads to waning coefficients and, second, illustrates empirically how selection leads to biased estimates of the effect of family background on educational transitions. Our empirical analysis using data from...

  11. Mode

    DEFF Research Database (Denmark)

    Mackinney-Valentin, Maria

    A textbook for school children 13-16 on fashion. Ethics, designers, social identity, zeitgeist, and gender are among the key themes.......A textbook for school children 13-16 on fashion. Ethics, designers, social identity, zeitgeist, and gender are among the key themes....

  12. Theory of Modes and Impulses

    Science.gov (United States)

    Apsche, Jack A.

    2005-01-01

    In his work on the Theory of Modes, Beck (1996) suggested that there were flaws with his cognitive theory. He suggested that though there are shortcomings to his cognitive theory, there were not similar shortcomings to the practice of Cognitive Therapy. The author suggests that if there are shortcomings to cognitive theory the same shortcomings…

  13. News on the Scissors Mode

    Science.gov (United States)

    Pietralla, N.; Beller, J.; Beck, T.; Derya, V.; Löher, B.; Romig, C.; Savran, D.; Scheck, M.; Tornow, W.; Zweidinger, M.

    2014-09-01

    We report on our recent nuclear resonance fluorescence experiments on l52,l54,l56Gd. Decay branches of the scissors mode to intrinsic excitations are observed. They are interpreted as a new signature for a spherical-to-deformed nuclear shape phase transition.

  14. Single-mode optical fibres

    CERN Document Server

    Cancellieri, G

    1991-01-01

    This book describes signal propagation in single-mode optical fibres for telecommunication applications. Such description is based on the analysis of field propagation, considering waveguide properties and also some of the particular characteristics of the material fibre. The book covers such recent advances as, coherent transmissions; optical amplification; MIR fibres; polarization maintaining; polarization diversity and photon counting.

  15. Rubble Mound Breakwater Failure Modes

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Z., Liu

    1995-01-01

    The RMBFM-Project (Rubble Mound Breakwater Failure Modes) is sponsored by the Directorate General XII of the Commission of the European Communities under the Contract MAS-CT92- 0042, with the objective of contributing to the development of rational methods for the design of rubble mound breakwate...

  16. Mode structure of active resonators

    NARCIS (Netherlands)

    Ernst, G.J.; Witteman, W.J.

    1973-01-01

    An analysis is made of the mode structure of lasers when the interaction with the active medium is taken into account. We consider the combined effect of gain and refractive-index variations for arbitrary mirror configurations. Using a dimensionless round-trip matrix for a medium with a quadratic

  17. Energy balance in tearing modes

    International Nuclear Information System (INIS)

    Wesson, J.A.

    1993-01-01

    The energy balance in tearing modes is described in terms of exact separate energy balance equations. Each of these equations describes identified physical processes, and their sum gives the conservation of total energy. One of the energy balance equations corresponds to Furth's description. (Author)

  18. Adaptive enhancement of optical fringe patterns by selective reconstruction using FABEMD algorithm and Hilbert spiral transform.

    Science.gov (United States)

    Trusiak, Maciej; Patorski, Krzysztof; Wielgus, Maciej

    2012-10-08

    Presented method for fringe pattern enhancement has been designed for processing and analyzing low quality fringe patterns. It uses a modified fast and adaptive bidimensional empirical mode decomposition (FABEMD) for the extraction of bidimensional intrinsic mode functions (BIMFs) from an interferogram. Fringe pattern is then selectively reconstructed (SR) taking the regions of selected BIMFs with high modulation values only. Amplitude demodulation and normalization of the reconstructed image is conducted using the spiral phase Hilbert transform (HS). It has been tested using computer generated interferograms and real data. The performance of the presented SR-FABEMD-HS method is compared with other normalization techniques. Its superiority, potential and robustness to high fringe density variations and the presence of noise, modulation and background illumination defects in analyzed fringe patterns has been corroborated.

  19. Empirical Equation Based Chirality (n, m Assignment of Semiconducting Single Wall Carbon Nanotubes from Resonant Raman Scattering Data

    Directory of Open Access Journals (Sweden)

    Md Shamsul Arefin

    2012-12-01

    Full Text Available This work presents a technique for the chirality (n, m assignment of semiconducting single wall carbon nanotubes by solving a set of empirical equations of the tight binding model parameters. The empirical equations of the nearest neighbor hopping parameters, relating the term (2n, m with the first and second optical transition energies of the semiconducting single wall carbon nanotubes, are also proposed. They provide almost the same level of accuracy for lower and higher diameter nanotubes. An algorithm is presented to determine the chiral index (n, m of any unknown semiconducting tube by solving these empirical equations using values of radial breathing mode frequency and the first or second optical transition energy from resonant Raman spectroscopy. In this paper, the chirality of 55 semiconducting nanotubes is assigned using the first and second optical transition energies. Unlike the existing methods of chirality assignment, this technique does not require graphical comparison or pattern recognition between existing experimental and theoretical Kataura plot.

  20. Empirical Equation Based Chirality (n, m) Assignment of Semiconducting Single Wall Carbon Nanotubes from Resonant Raman Scattering Data

    Science.gov (United States)

    Arefin, Md Shamsul

    2012-01-01

    This work presents a technique for the chirality (n, m) assignment of semiconducting single wall carbon nanotubes by solving a set of empirical equations of the tight binding model parameters. The empirical equations of the nearest neighbor hopping parameters, relating the term (2n− m) with the first and second optical transition energies of the semiconducting single wall carbon nanotubes, are also proposed. They provide almost the same level of accuracy for lower and higher diameter nanotubes. An algorithm is presented to determine the chiral index (n, m) of any unknown semiconducting tube by solving these empirical equations using values of radial breathing mode frequency and the first or second optical transition energy from resonant Raman spectroscopy. In this paper, the chirality of 55 semiconducting nanotubes is assigned using the first and second optical transition energies. Unlike the existing methods of chirality assignment, this technique does not require graphical comparison or pattern recognition between existing experimental and theoretical Kataura plot. PMID:28348319