Transformational leadership sub-dimensions and their link to leaders' personality and performance

NARCIS (Netherlands)

Deinert, A.; Homan, A.C.; Boer, D.; Voelpel, S.C.; Gutermann, D.

2015-01-01

The multi-dimensionality of the transformational leadership construct has been under debate in the last decades. To shed more light on this issue, we conducted a meta-analysis (k = 58 studies), examining the transformational leadership sub-dimensions and their links to leader personality and

Precise and fast spatial-frequency analysis using the iterative local Fourier transform.

Science.gov (United States)

Lee, Sukmock; Choi, Heejoo; Kim, Dae Wook

2016-09-19

The use of the discrete Fourier transform has decreased since the introduction of the fast Fourier transform (fFT), which is a numerically efficient computing process. This paper presents the iterative local Fourier transform (ilFT), a set of new processing algorithms that iteratively apply the discrete Fourier transform within a local and optimal frequency domain. The new technique achieves 210 times higher frequency resolution than the fFT within a comparable computation time. The method's superb computing efficiency, high resolution, spectrum zoom-in capability, and overall performance are evaluated and compared to other advanced high-resolution Fourier transform techniques, such as the fFT combined with several fitting methods. The effectiveness of the ilFT is demonstrated through the data analysis of a set of Talbot self-images (1280 × 1024 pixels) obtained with an experimental setup using grating in a diverging beam produced by a coherent point source.

Cascaded multiplexed optical link on a telecommunication network for frequency dissemination.

Science.gov (United States)

Lopez, Olivier; Haboucha, Adil; Kéfélian, Fabien; Jiang, Haifeng; Chanteau, Bruno; Roncin, Vincent; Chardonnet, Christian; Amy-Klein, Anne; Santarelli, Giorgio

2010-08-02

We demonstrate a cascaded optical link for ultrastable frequency dissemination comprised of two compensated links of 150 km and a repeater station. Each link includes 114 km of Internet fiber simultaneously carrying data traffic through a dense wavelength division multiplexing technology, and passes through two routing centers of the telecommunication network. The optical reference signal is inserted in and extracted from the communication network using bidirectional optical add-drop multiplexers. The repeater station operates autonomously ensuring noise compensation on the two links and the ultra-stable signal optical regeneration. The compensated link shows a fractional frequency instability of 3 x 10(-15) at one second measurement time and 5 x 10(-20) at 20 hours. This work paves the way to a wide dissemination of ultra-stable optical clock signals between distant laboratories via the Internet network.

Experiences with non-intrusive monitoring of distribution transformers based on the on-line frequency response

Directory of Open Access Journals (Sweden)

Eduardo Gomez Luna

2015-01-01

Full Text Available The following article presents the results obtained in experiences that use the Impulse Frequency Response Analysis (IFRA method with a transformer in service. The IFRA method has been implemented in order to transform the transient signals to the frequency domain using Discrete Fourier Transform (DFT. However, it can be considered that the DFT is not the most suitable tool for this type of analysis, since, by definition, this tool is useful for processing stationary signals. Taking that into consideration, the analysis of transient signals could be hypothetically improved by using continuous wavelet transform (CWT, given their variable time/frequency resolution. The analysis of transient signals in Wavelet domain has improved the repeatability of the frequency response curves, as it has been ob-served in experimental results. The proposed on-line IFRA method, based on Wavelet transform, was validated under load and no-load conditions on a 150 kVA three-phase transformer 13200/225 Volts, in the Campus of the Universidad del Valle, Cali, Colombia.

The Simulation of the Traction Drive with Middle-Frequency Transformer

Directory of Open Access Journals (Sweden)

Pavel Drabek

2008-01-01

Full Text Available This paper presents research motivated by industrial demand for special traction drive topology devoted to minimization of traction transformer weight against topology with classical 50Hz traction transformer. The special traction drive topology for AC power systems consists of input high voltage trolley converter (single phase matrix converter –middle frequency transformer - output converter - traction motor has been described. The main attention has been given tothe control algorithm of the traction topology (inserting of NULL vector of matrix converter and Two-value control ofsecondary active rectifier.

Design and development of high voltage and high frequency center tapped transformer for HVDC test generator

International Nuclear Information System (INIS)

Thaker, Urmil; Saurabh Kumar; Amal, S.; Baruah, U.K.; Bhatt, Animesh

2015-01-01

A High Voltage center tapped transformer for high frequency application had been designed, fabricated, and tested. It was designed as a part of 200 kV HVDC Test Generator. The High Frequency operation of transformer increases power density. Therefore it is possible to reduce power supply volume. The step up ratio in High Voltage transformer is limited due to stray capacitance and leakage inductance. The limit was overcome by winding multi secondary outputs. Switching frequency of transformer was 15.8 kHz. Input and output voltages of transformer were 270V and 16.5kV-0V-16.5kV respectively. Power rating of transformer is 7kVA. High Voltage transformer with various winding and core arrangement was fabricated to check variation in electrical characteristics. The transformer used a ferrite core (E Type) and nylon insulated primary and secondary bobbins. Two set of E-E geometry cores had been stacked in order to achieve the estimated core volume. Compared with traditional high voltage transformer, this transformer had good thermal behavior, good line insulation properties and a high power density. In this poster, design procedures, development stages and test results of high voltage and high frequency transformer are presented. Results of various parameters such as transformer loss, temperature rise, insulation properties, impedance of primary and secondary winding, and voltage regulation are discussed. (author)

Frequency hopping signal detection based on wavelet decomposition and Hilbert-Huang transform

Science.gov (United States)

Zheng, Yang; Chen, Xihao; Zhu, Rui

2017-07-01

Frequency hopping (FH) signal is widely adopted by military communications as a kind of low probability interception signal. Therefore, it is very important to research the FH signal detection algorithm. The existing detection algorithm of FH signals based on the time-frequency analysis cannot satisfy the time and frequency resolution requirement at the same time due to the influence of window function. In order to solve this problem, an algorithm based on wavelet decomposition and Hilbert-Huang transform (HHT) was proposed. The proposed algorithm removes the noise of the received signals by wavelet decomposition and detects the FH signals by Hilbert-Huang transform. Simulation results show the proposed algorithm takes into account both the time resolution and the frequency resolution. Correspondingly, the accuracy of FH signals detection can be improved.

Fourier transform NMR

International Nuclear Information System (INIS)

Hallenga, K.

1991-01-01

This paper discusses the concept of Fourier transformation one of the many precious legacies of the French mathematician Jean Baptiste Joseph Fourier, essential for understanding the link between continuous-wave (CW) and Fourier transform (FT) NMR. Although in modern FT NMR the methods used to obtain a frequency spectrum from the time-domain signal may vary greatly, from the efficient Cooley-Tukey algorithm to very elaborate iterative least-square methods based other maximum entropy method or on linear prediction, the principles for Fourier transformation are unchanged and give invaluable insight into the interconnection of many pairs of physical entities called Fourier pairs

Analysis of Energy Overshoot of High Frequency Waves with Wavelet Transform

Institute of Scientific and Technical Information of China (English)

WEN Fan

2000-01-01

A study is made on the overshoot phenomena in wind-generated waves. The surface displace ments of time-growing waves are measured at four fetches in a wind wave channel. The evolution of high frequency waves is displayed with wavelet transform. The results are compared with Sutherland＇s. It is found that high frequency wave components experience much stronger energy overshoot in the evolution.The energy of high frequency waves decreases greatly after overshoot

Frequency Correction for MIRO Chirp Transformation Spectroscopy Spectrum

Science.gov (United States)

Lee, Seungwon

2012-01-01

This software processes the flyby spectra of the Chirp Transform Spectrometer (CTS) of the Microwave Instrument for Rosetta Orbiter (MIRO). The tool corrects the effect of Doppler shift and local-oscillator (LO) frequency shift during the flyby mode of MIRO operations. The frequency correction for CTS flyby spectra is performed and is integrated with multiple spectra into a high signal-to-noise averaged spectrum at the rest-frame RF frequency. This innovation also generates the 8 molecular line spectra by dividing continuous 4,096-channel CTS spectra. The 8 line spectra can then be readily used for scientific investigations. A spectral line that is at its rest frequency in the frame of the Earth or an asteroid will be observed with a time-varying Doppler shift as seen by MIRO. The frequency shift is toward the higher RF frequencies on approach, and toward lower RF frequencies on departure. The magnitude of the shift depends on the flyby velocity. The result of time-varying Doppler shift is that of an observed spectral line will be seen to move from channel to channel in the CTS spectrometer. The direction (higher or lower frequency) in the spectrometer depends on the spectral line frequency under consideration. In order to analyze the flyby spectra, two steps are required. First, individual spectra must be corrected for the Doppler shift so that individual spectra can be superimposed at the same rest frequency for integration purposes. Second, a correction needs to be applied to the CTS spectra to account for the LO frequency shifts that are applied to asteroid mode.

Design and Measurement of Planar Toroidal Transformers for Very High Frequency Power Applications

DEFF Research Database (Denmark)

Knott, Arnold; Pejtersen, Jens

2012-01-01

The quest for higher power density has led to research of very high frequency (30-300 MHz) power converters. Magnetic components based on ferrite cores have limited application within this frequency range due to increased core loss. Air-core magnetics is a viable alternative as they do not exhibit...... core loss. The drawback of most air-core magnetics is that the magnetic field is not contained within a closed shape, and it is thus prone to cause electro magnetic interference. A toroidal air-core inductor configuration can be used to contain the magnetic field. This work presents a novel air......-core toroidal transformer configuration for use in very high frequency power conversion applications. Two prototype transformers (10:10 and 12:12) have been implemented using conventional four layer printed circuit board technology. The transformers have been characterized by two port Z-parameters, which have...

Pitch link loads reduction of variable speed rotors by variable tuning frequency fluidlastic isolators

Directory of Open Access Journals (Sweden)

Han Dong

2015-10-01

Full Text Available To reduce the pitch link loads of variable speed rotors, variable tuning frequency fluidlastic isolators are proposed. This isolator utilizes the variation of centrifugal force due to the change of rotor speed to change the tuning port area ratio, which can change the tuning frequency of the isolator. A rotor model including the model of fluidlastic isolator is coupled with a fuselage model to predict the steady responses of the rotor system in forward flight. The aeroelastic analyses indicate that distinct performance improvement in pitch link load control can be achieved by the utilization of variable frequency isolators compared with the constant tuning frequency isolators. The 4/rev (per revolution pitch link load is observed to be reduced by 87.6% compared with the increase of 56.3% by the constant frequency isolator, when the rotor speed is reduced by 16.7%. The isolation ability at different rotor speeds in different flight states is investigated. To achieve overall load reduction within the whole range of rotor speed, the strategy of the variation of tuning frequency is adjusted. The results indicate that the 4/rev pitch link load within the whole rotor speed range is decreased.

Experiences with non-intrusive monitoring of distribution transformers based on the on-line frequency response

OpenAIRE

Eduardo Gomez Luna

2015-01-01

The following article presents the results obtained in experiences that use the Impulse Frequency Response Analysis (IFRA) method with a transformer in service. The IFRA method has been implemented in order to transform the transient signals to the frequency domain using Discrete Fourier Transform (DFT). However, it can be considered that the DFT is not the most suitable tool for this type of analysis, since, by definition, this tool is useful for processing stationary signals. Taking that in...

Agrobacterium-mediated high-frequency transformation of an elite commercial maize (Zea mays L.) inbred line.

Science.gov (United States)

Cho, Myeong-Je; Wu, Emily; Kwan, Jackie; Yu, Maryanne; Banh, Jenny; Linn, Wutt; Anand, Ajith; Li, Zhi; TeRonde, Susan; Register, James C; Jones, Todd J; Zhao, Zuo-Yu

2014-10-01

An improved Agrobacterium -mediated transformation protocol is described for a recalcitrant commercial maize elite inbred with optimized media modifications and AGL1. These improvements can be applied to other commercial inbreds. This study describes a significantly improved Agrobacterium-mediated transformation protocol in a recalcitrant commercial maize elite inbred, PHR03, using optimal co-cultivation, resting and selection media. The use of green regenerative tissue medium components, high copper and 6-benzylaminopurine, in resting and selection media dramatically increased the transformation frequency. The use of glucose in resting medium further increased transformation frequency by improving the tissue induction rate, tissue survival and tissue proliferation from immature embryos. Consequently, an optimal combination of glucose, copper and cytokinin in the co-cultivation, resting and selection media resulted in significant improvement from 2.6 % up to tenfold at the T0 plant level using Agrobacterium strain LBA4404 in transformation of PHR03. Furthermore, we evaluated four different Agrobacterium strains, LBA4404, AGL1, EHA105, and GV3101 for transformation frequency and event quality. AGL1 had the highest transformation frequency with up to 57.1 % at the T0 plant level. However, AGL1 resulted in lower quality events (defined as single copy for transgenes without Agrobacterium T-DNA backbone) when compared to LBA4404 (30.1 vs 25.6 %). We propose that these improvements can be applied to other recalcitrant commercial maize inbreds.

A Review of Frequency Response Analysis Methods for Power Transformer Diagnostics

Directory of Open Access Journals (Sweden)

Saleh Alsuhaibani

2016-10-01

Full Text Available Power transformers play a critical role in electric power networks. Such transformers can suffer failures due to multiple stresses and aging. Thus, assessment of condition and diagnostic techniques are of great importance for improving power network reliability and service continuity. Several techniques are available to diagnose the faults within the power transformer. Frequency response analysis (FRA method is a powerful technique for diagnosing transformer winding deformation and several other types of problems that are caused during manufacture, transportation, installation and/or service life. This paper provides a comprehensive review on FRA methods and their applications in diagnostics and fault identification for power transformers. The paper discusses theory and applications of FRA methods as well as various issues and challenges faced in the application of this method.

Influence of lasers with non-white frequency noise on the design of coherent optical links

DEFF Research Database (Denmark)

Kakkar, Aditya; Navarro, Jaime Rodrigo; Schatz, Richard

2017-01-01

We experimentally demonstrate for a 28 Gbaud 64-QAM metro link that the LO frequency noise causes timing impairment. Results show the existence of LO frequency noise spectrum regimes where different design criteria apply.......We experimentally demonstrate for a 28 Gbaud 64-QAM metro link that the LO frequency noise causes timing impairment. Results show the existence of LO frequency noise spectrum regimes where different design criteria apply....

The determination of frequency response function of the RSG Gas by laplace transform analysis

International Nuclear Information System (INIS)

Tukiran, S.; Surian, P.; Jujuratisbela, U.

1997-01-01

The response function of the RSG-GAS reactor system to the reactivity perturbations is necessary to be analyzed due to the interrelation with reliability and safety of reactor operation. the response depends on the power frequency response function H(s), while H(s) depends on the zero power frequency response function Z(s) and dynamic power coefficient of reactivity Kp(s) determination of the frequency response function of the RSG-GAS reactor was done by Fourier transform analysis method. Z(s) was obtained by fourier transform of P(t) and Cj(t) became P(S) and Cj(s) in point kinetic equations. Second order of simpson rule was used for completion of its numerical integration. then. LYMPR (Laplace transform for multipurpose reactor) code was made with fortran 77 computer language in vax 8550 system. the LTMPR code is able to determine the frequency response function and period-reactivity relation of RSG-GAS reactor by rod drop method. Profile of power as rod drop, zero power (without reactivity feedback) was used for determination frequency response of RSG-GAS reactor. The results of calculations are in a good agreement with experiment result, so the LTMPR code can be used for analysis response frequency of the RSG-GAS reactor

Corrections for frequency domain transformations of Winfrith binary cross correlator responses

International Nuclear Information System (INIS)

Cummins, J.D.

1968-04-01

This report considers the corrections for frequency domain transformations of Winfrith binary cross correlator responses; (i) for the finite bandwidth of the equivalent input signal; (2) for the finite time required for the actuator to move between the two positions appropriate to the two levels of the periodic binary chain code input and (3) for the averaging of experimental determinations of the system frequency response and calculations of the standard deviations of the modulus and phase of the frequency responses determined from the cross correlator responses. (author)

A study on thermal characteristics analysis model of high frequency switching transformer

Science.gov (United States)

Yoo, Jin-Hyung; Jung, Tae-Uk

2015-05-01

Recently, interest has been shown in research on the module-integrated converter (MIC) in small-scale photovoltaic (PV) generation. In an MIC, the voltage boosting high frequency transformer should be designed to be compact in size and have high efficiency. In response to the need to satisfy these requirements, this paper presents a coupled electromagnetic analysis model of a transformer connected with a high frequency switching DC-DC converter circuit while considering thermal characteristics due to the copper and core losses. A design optimization procedure for high efficiency is also presented using this design analysis method, and it is verified by the experimental result.

Linking EEG signals, brain functions and mental operations: Advantages of the Laplacian transformation.

Science.gov (United States)

Vidal, Franck; Burle, Boris; Spieser, Laure; Carbonnell, Laurence; Meckler, Cédric; Casini, Laurence; Hasbroucq, Thierry

2015-09-01

Electroencephalography (EEG) is a very popular technique for investigating brain functions and/or mental processes. To this aim, EEG activities must be interpreted in terms of brain and/or mental processes. EEG signals being a direct manifestation of neuronal activity it is often assumed that such interpretations are quite obvious or, at least, straightforward. However, they often rely on (explicit or even implicit) assumptions regarding the structures supposed to generate the EEG activities of interest. For these assumptions to be used appropriately, reliable links between EEG activities and the underlying brain structures must be established. Because of volume conduction effects and the mixture of activities they induce, these links are difficult to establish with scalp potential recordings. We present different examples showing how the Laplacian transformation, acting as an efficient source separation method, allowed to establish more reliable links between EEG activities and brain generators and, ultimately, with mental operations. The nature of those links depends on the depth of inferences that can vary from weak to strong. Along this continuum, we show that 1) while the effects of experimental manipulation can appear widely distributed with scalp potentials, Laplacian transformation allows to reveal several generators contributing (in different manners) to these modulations, 2) amplitude variations within the same set of generators can generate spurious differences in scalp potential topographies, often interpreted as reflecting different source configurations. In such a case, Laplacian transformation provides much more similar topographies, evidencing the same generator(s) set, and 3) using the LRP as an index of response activation most often produces ambiguous results, Laplacian-transformed response-locked ERPs obtained over motor areas allow resolving these ambiguities. Copyright © 2015 Elsevier B.V. All rights reserved.

A simple structure wavelet transform circuit employing function link neural networks and SI filters

Science.gov (United States)

Mu, Li; Yigang, He

2016-12-01

Signal processing by means of analog circuits offers advantages from a power consumption viewpoint. Implementing wavelet transform (WT) using analog circuits is of great interest when low-power consumption becomes an important issue. In this article, a novel simple structure WT circuit in analog domain is presented by employing functional link neural network (FLNN) and switched-current (SI) filters. First, the wavelet base is approximated using FLNN algorithms for giving a filter transfer function that is suitable for simple structure WT circuit implementation. Next, the WT circuit is constructed with the wavelet filter bank, whose impulse response is the approximated wavelet and its dilations. The filter design that follows is based on a follow-the-leader feedback (FLF) structure with multiple output bilinear SI integrators and current mirrors as the main building blocks. SI filter is well suited for this application since the dilation constant across different scales of the transform can be precisely implemented and controlled by the clock frequency of the circuit with the same system architecture. Finally, to illustrate the design procedure, a seventh-order FLNN-approximated Gaussian wavelet is implemented as an example. Simulations have successfully verified that the designed simple structure WT circuit has low sensitivity, low-power consumption and litter effect to the imperfections.

Modelling the effect of non-uniform radon progeny activities on transformation frequencies in human bronchial airways

International Nuclear Information System (INIS)

Fakir, H.; Hofmann, W.; Aubineau-Laniece, I.

2006-01-01

The effects of radiological and morphological source heterogeneities in straight and Y-shaped bronchial airways on hit frequencies and Micro-dosimetric quantities in epithelial cells have been investigated previously. The goal of the present study is to relate these physical quantities to transformation frequencies in sensitive target cells and to radon-induced lung cancer risk. Based on an effect-specific track length model, computed linear energy transfer (LET) spectra were converted to corresponding transformation frequencies for different activity distributions and source - target configurations. Average transformation probabilities were considerably enhanced for radon progeny accumulations and target cells at the carinal ridge, relative to uniform activity distributions and target cells located along the curved and straight airway portions at the same exposure level. Although uncorrelated transformation probabilities produce a linear dose - effect relationship, correlated transformations first increase depending on the LET, but then decrease significantly when exceeding a defined number of hits or cumulative exposure level. (authors)

Frequency response variation of two offshore wind park transformers with different tap changer positions

DEFF Research Database (Denmark)

Arana Aristi, Iván; Holbøll, Joachim; Sørensen, T

2010-01-01

This paper presents the results of several sweep frequency response analysis (SFRA) measurements performed on two identical offshore wind farm transformers. A comparison is made between the transformers based on different recommended measurements and procedures, different measurement systems...

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

International Nuclear Information System (INIS)

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

2014-01-01

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

COMPARATIVE ANALYSIS OF APPLICATION EFFICIENCY OF ORTHOGONAL TRANSFORMATIONS IN FREQUENCY ALGORITHMS FOR DIGITAL IMAGE WATERMARKING

Directory of Open Access Journals (Sweden)

Vladimir A. Batura

2014-11-01

Full Text Available The efficiency of orthogonal transformations application in the frequency algorithms of the digital watermarking of still images is examined. Discrete Hadamard transform, discrete cosine transform and discrete Haar transform are selected. Their effectiveness is determined by the invisibility of embedded in digital image watermark and its resistance to the most common image processing operations: JPEG-compression, noising, changing of the brightness and image size, histogram equalization. The algorithm for digital watermarking and its embedding parameters remain unchanged at these orthogonal transformations. Imperceptibility of embedding is defined by the peak signal to noise ratio, watermark stability– by Pearson's correlation coefficient. Embedding is considered to be invisible, if the value of the peak signal to noise ratio is not less than 43 dB. Embedded watermark is considered to be resistant to a specific attack, if the Pearson’s correlation coefficient is not less than 0.5. Elham algorithm based on the image entropy is chosen for computing experiment. Computing experiment is carried out according to the following algorithm: embedding of a digital watermark in low-frequency area of the image (container by Elham algorithm, exposure to a harmful influence on the protected image (cover image, extraction of a digital watermark. These actions are followed by quality assessment of cover image and watermark on the basis of which efficiency of orthogonal transformation is defined. As a result of computing experiment it was determined that the choice of the specified orthogonal transformations at identical algorithm and parameters of embedding doesn't influence the degree of imperceptibility for a watermark. Efficiency of discrete Hadamard transform and discrete cosine transformation in relation to the attacks chosen for experiment was established based on the correlation indicators. Application of discrete Hadamard transform increases

Evaluation of the high-voltage high-frequency transformer insulating materials for satellites

International Nuclear Information System (INIS)

Kurita, Hiroshi; Hasegawa, Taketoshi; Hirasawa, Eiichi; Gonai, Toshio; Ohsuga, Hiroyuki.

1987-01-01

Environment resistance evaluation was made of the insulating materials of impregnated injection type for high-voltage high-frequency transformers mounted in satellites. (1) The stress occurring in the impregnated injection type resin is small in silicon resin and urethane resin and large in epoxy resin. (2) The dielectric characteristic at high frequency is good in silicone resin. In epoxy resin, when the transformer is operated at high temperature, its thermal runaway may take place. (3) The radiation deterioration at 1 Mrad - 10 Mrad is slight in urethane resin. (4) The degassing is not good in silicone resin. (5) The adhesive power is good in urethane resin. (6) From the above results, in silicone resin there is problem in degassing and adhesive power. In epoxy resin there is problem in stress and dielectric characteristic. (Mori, K.)

Recognition of Frequency Modulated Whistle-Like Sounds by a Bottlenose Dolphin (Tursiops truncatus) and Humans with Transformations in Amplitude, Duration and Frequency

Science.gov (United States)

Branstetter, Brian K.; DeLong, Caroline M.; Dziedzic, Brandon; Black, Amy; Bakhtiari, Kimberly

2016-01-01

Bottlenose dolphins (Tursiops truncatus) use the frequency contour of whistles produced by conspecifics for individual recognition. Here we tested a bottlenose dolphin’s (Tursiops truncatus) ability to recognize frequency modulated whistle-like sounds using a three alternative matching-to-sample paradigm. The dolphin was first trained to select a specific object (object A) in response to a specific sound (sound A) for a total of three object-sound associations. The sounds were then transformed by amplitude, duration, or frequency transposition while still preserving the frequency contour of each sound. For comparison purposes, 30 human participants completed an identical task with the same sounds, objects, and training procedure. The dolphin’s ability to correctly match objects to sounds was robust to changes in amplitude with only a minor decrement in performance for short durations. The dolphin failed to recognize sounds that were frequency transposed by plus or minus ½ octaves. Human participants demonstrated robust recognition with all acoustic transformations. The results indicate that this dolphin’s acoustic recognition of whistle-like sounds was constrained by absolute pitch. Unlike human speech, which varies considerably in average frequency, signature whistles are relatively stable in frequency, which may have selected for a whistle recognition system invariant to frequency transposition. PMID:26863519

Recognition of Frequency Modulated Whistle-Like Sounds by a Bottlenose Dolphin (Tursiops truncatus and Humans with Transformations in Amplitude, Duration and Frequency.

Directory of Open Access Journals (Sweden)

Brian K Branstetter

Full Text Available Bottlenose dolphins (Tursiops truncatus use the frequency contour of whistles produced by conspecifics for individual recognition. Here we tested a bottlenose dolphin's (Tursiops truncatus ability to recognize frequency modulated whistle-like sounds using a three alternative matching-to-sample paradigm. The dolphin was first trained to select a specific object (object A in response to a specific sound (sound A for a total of three object-sound associations. The sounds were then transformed by amplitude, duration, or frequency transposition while still preserving the frequency contour of each sound. For comparison purposes, 30 human participants completed an identical task with the same sounds, objects, and training procedure. The dolphin's ability to correctly match objects to sounds was robust to changes in amplitude with only a minor decrement in performance for short durations. The dolphin failed to recognize sounds that were frequency transposed by plus or minus ½ octaves. Human participants demonstrated robust recognition with all acoustic transformations. The results indicate that this dolphin's acoustic recognition of whistle-like sounds was constrained by absolute pitch. Unlike human speech, which varies considerably in average frequency, signature whistles are relatively stable in frequency, which may have selected for a whistle recognition system invariant to frequency transposition.

A High-Precision Time-Frequency Entropy Based on Synchrosqueezing Generalized S-Transform Applied in Reservoir Detection

Directory of Open Access Journals (Sweden)

Hui Chen

2018-06-01

Full Text Available According to the fact that high frequency will be abnormally attenuated when seismic signals travel across reservoirs, a new method, which is named high-precision time-frequency entropy based on synchrosqueezing generalized S-transform, is proposed for hydrocarbon reservoir detection in this paper. First, the proposed method obtains the time-frequency spectra by synchrosqueezing generalized S-transform (SSGST, which are concentrated around the real instantaneous frequency of the signals. Then, considering the characteristics and effects of noises, we give a frequency constraint condition to calculate the entropy based on time-frequency spectra. The synthetic example verifies that the entropy will be abnormally high when seismic signals have an abnormal attenuation. Besides, comparing with the GST time-frequency entropy and the original SSGST time-frequency entropy in field data, the results of the proposed method show higher precision. Moreover, the proposed method can not only accurately detect and locate hydrocarbon reservoirs, but also effectively suppress the impact of random noises.

Spatial transformation-enabled electromagnetic devices: from radio frequencies to optical wavelengths

Science.gov (United States)

Jiang, Zhi Hao; Turpin, Jeremy P.; Morgan, Kennith; Lu, Bingqian; Werner, Douglas H.

2015-01-01

Transformation optics provides scientists and engineers with a new powerful design paradigm to manipulate the flow of electromagnetic waves in a user-defined manner and with unprecedented flexibility, by controlling the spatial distribution of the electromagnetic properties of a medium. Using this approach, over the past decade, various previously undiscovered physical wave phenomena have been revealed and novel electromagnetic devices have been demonstrated throughout the electromagnetic spectrum. In this paper, we present versatile theoretical and experimental investigations on designing transformation optics-enabled devices for shaping electromagnetic wave radiation and guidance, at both radio frequencies and optical wavelengths. Different from conventional coordinate transformations, more advanced and versatile coordinate transformations are exploited here to benefit diverse applications, thereby providing expanded design flexibility, enhanced device performance, as well as reduced implementation complexity. These design examples demonstrate the comprehensive capability of transformation optics in controlling electromagnetic waves, while the associated novel devices will open up new paths towards future integrated electromagnetic component synthesis and design, from microwave to optical spectral regimes. PMID:26217054

Spatial transformation-enabled electromagnetic devices: from radio frequencies to optical wavelengths.

Science.gov (United States)

Jiang, Zhi Hao; Turpin, Jeremy P; Morgan, Kennith; Lu, Bingqian; Werner, Douglas H

2015-08-28

Transformation optics provides scientists and engineers with a new powerful design paradigm to manipulate the flow of electromagnetic waves in a user-defined manner and with unprecedented flexibility, by controlling the spatial distribution of the electromagnetic properties of a medium. Using this approach, over the past decade, various previously undiscovered physical wave phenomena have been revealed and novel electromagnetic devices have been demonstrated throughout the electromagnetic spectrum. In this paper, we present versatile theoretical and experimental investigations on designing transformation optics-enabled devices for shaping electromagnetic wave radiation and guidance, at both radio frequencies and optical wavelengths. Different from conventional coordinate transformations, more advanced and versatile coordinate transformations are exploited here to benefit diverse applications, thereby providing expanded design flexibility, enhanced device performance, as well as reduced implementation complexity. These design examples demonstrate the comprehensive capability of transformation optics in controlling electromagnetic waves, while the associated novel devices will open up new paths towards future integrated electromagnetic component synthesis and design, from microwave to optical spectral regimes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Recent progress in synchrotron-based frequency-domain Fourier-transform THz-EPR.

Science.gov (United States)

Nehrkorn, Joscha; Holldack, Karsten; Bittl, Robert; Schnegg, Alexander

2017-07-01

We describe frequency-domain Fourier-transform THz-EPR as a method to assign spin-coupling parameters of high-spin (S>1/2) systems with very large zero-field splittings. The instrumental foundations of synchrotron-based FD-FT THz-EPR are presented, alongside with a discussion of frequency-domain EPR simulation routines. The capabilities of this approach is demonstrated for selected mono- and multinuclear HS systems. Finally, we discuss remaining challenges and give an outlook on the future prospects of the technique. Copyright © 2017 Elsevier Inc. All rights reserved.

Single-trial log transformation is optimal in frequency analysis of resting EEG alpha.

Science.gov (United States)

Smulders, Fren T Y; Ten Oever, Sanne; Donkers, Franc C L; Quaedflieg, Conny W E M; van de Ven, Vincent

2018-02-01

The appropriate definition and scaling of the magnitude of electroencephalogram (EEG) oscillations is an underdeveloped area. The aim of this study was to optimize the analysis of resting EEG alpha magnitude, focusing on alpha peak frequency and nonlinear transformation of alpha power. A family of nonlinear transforms, Box-Cox transforms, were applied to find the transform that (a) maximized a non-disputed effect: the increase in alpha magnitude when the eyes are closed (Berger effect), and (b) made the distribution of alpha magnitude closest to normal across epochs within each participant, or across participants. The transformations were performed either at the single epoch level or at the epoch-average level. Alpha peak frequency showed large individual differences, yet good correspondence between various ways to estimate it in 2 min of eyes-closed and 2 min of eyes-open resting EEG data. Both alpha magnitude and the Berger effect were larger for individual alpha than for a generic (8-12 Hz) alpha band. The log-transform on single epochs (a) maximized the t-value of the contrast between the eyes-open and eyes-closed conditions when tested within each participant, and (b) rendered near-normally distributed alpha power across epochs and participants, thereby making further transformation of epoch averages superfluous. The results suggest that the log-normal distribution is a fundamental property of variations in alpha power across time in the order of seconds. Moreover, effects on alpha power appear to be multiplicative rather than additive. These findings support the use of the log-transform on single epochs to achieve appropriate scaling of alpha magnitude. © 2018 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Embodied mental rotation: A special link between egocentric transformation and the bodily self

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Sandra eKaltner

2014-06-01

Full Text Available This experiment investigated the influence of motor expertise on object-based versus egocentric transformations in a chronometric mental rotation task using images of either the own or another person’s body as stimulus material. According to the embodied cognition viewpoint, we hypothesized motor-experts to outperform non-motor experts specifically in the egocentric condition because of higher kinesthetic representation and motor simulations compared to object-based transformations. In line with this, we expected that images of the own body are solved faster than another person’s body stimuli. Results showed a benefit of motor expertise and representations of another person’s body, but only for the object-based transformation task. That is, this other-advantage diminishes in egocentric transformations. Since motor experts didn’t show any specific expertise in rotational movements, we concluded that using human bodies as stimulus material elicits embodied spatial transformations, which facilitates performance exclusively for egocentric transformations. Regarding stimulus material, the other-advantage ascribed to increased self-awareness-consciousness distracting attention-demanding resources, disappeared in the egocentric condition. This result may be due to the stronger link between the bodily self and motor representations compared to that emerging in object-based transformations.

Infrared and visual image fusion method based on discrete cosine transform and local spatial frequency in discrete stationary wavelet transform domain

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Jin, Xin; Jiang, Qian; Yao, Shaowen; Zhou, Dongming; Nie, Rencan; Lee, Shin-Jye; He, Kangjian

2018-01-01

In order to promote the performance of infrared and visual image fusion and provide better visual effects, this paper proposes a hybrid fusion method for infrared and visual image by the combination of discrete stationary wavelet transform (DSWT), discrete cosine transform (DCT) and local spatial frequency (LSF). The proposed method has three key processing steps. Firstly, DSWT is employed to decompose the important features of the source image into a series of sub-images with different levels and spatial frequencies. Secondly, DCT is used to separate the significant details of the sub-images according to the energy of different frequencies. Thirdly, LSF is applied to enhance the regional features of DCT coefficients, and it can be helpful and useful for image feature extraction. Some frequently-used image fusion methods and evaluation metrics are employed to evaluate the validity of the proposed method. The experiments indicate that the proposed method can achieve good fusion effect, and it is more efficient than other conventional image fusion methods.

Transforming the Medical Subject Headings into Linked Data: Creating the Authorized Version of MeSH in RDF.

Science.gov (United States)

Bushman, Barbara; Anderson, David; Fu, Gang

In February 2014 the National Library of Medicine formed the Linked Data Infrastructure Working Group to investigate the potential for publishing linked data, determine best practices for publishing linked data, and prioritize linked data projects, beginning with transforming the Medical Subject Headings as a linked data pilot. This article will review the pilot project to convert the Medical Subject Headings from XML to RDF. It will discuss the collaborative process, the technical and organizational issues tackled, and the future of linked data at the library.

A Novel Comb-Pilot Transform Domain Frequency Diversity Channel Estimation for OFDM System

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L. Liu

2009-12-01

Full Text Available Due to implementation complexity, the transform domain channel estimation based on training symbols or comb-type pilots has been paid more attention because of its efficient algorithm FFT/IFFT. However, in a comb-type OFDM system, the length of the channel impulse response is much smaller than the pilot number. In this case, the comb-pilot transform domain channel estimation only works as interpolation like the Least Squares (LS algorithm, but loses the noise suppression function. In this paper, we propose a novel frequency diversity channel estimation method via grouped pilots combining. With this estimator, not only the channel frequency response on non-pilot subcarriers can be interpolated, but also the noise can be better suppressed. Moreover, it does not need prior statistical characteristics of the wireless channel.

Leader identity as an antecedent of the frequency and consistency of transformational, consideration, and abusive leadership behaviors.

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Johnson, Russell E; Venus, Merlijn; Lanaj, Klodiana; Mao, Changguo; Chang, Chu-Hsiang

2012-11-01

Drawing from identity-based theories of leadership, we examined relations of leader identity with leader behavior and perceived effectiveness. To do so, we employed multiwave methodology to examine the differential impact of leaders' chronic collective, relational, and individual identities on the frequency and consistency of their subsequent transformational, consideration, and abusive behaviors over a 3-week period. We also examined the relative importance of these leadership behaviors for predicting perceived leader effectiveness as rated by subordinates and peers. Results indicated that leaders' collective and individual identities were uniquely related to transformational and abusive behaviors, respectively. We also observed a significant collective by individual identity interaction, such that abusive behaviors were most frequent when a strong individual identity was paired with a weak collective identity. Frequency of transformational behaviors accounted for the largest proportion of variance in perceived leader effectiveness, followed by frequency of abusive behaviors and consistency of transformational behaviors. We discuss the implications of these findings for leadership theory and development. (c) 2012 APA, all rights reserved.

An Intelligent Sensor for the Ultra-High-Frequency Partial Discharge Online Monitoring of Power Transformers

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Jian Li

2016-05-01

Full Text Available Ultra-high-frequency (UHF partial discharge (PD online monitoring is an effective way to inspect potential faults and insulation defects in power transformers. The construction of UHF PD online monitoring system is a challenge because of the high-frequency and wide-frequency band of the UHF PD signal. This paper presents a novel, intelligent sensor for UHF PD online monitoring based on a new method, namely a level scanning method. The intelligent sensor can directly acquire the statistical characteristic quantities and is characterized by low cost, few data to output and transmit, Ethernet functionality, and small size for easy installation. The prototype of an intelligent sensor was made. Actual UHF PD experiments with three typical artificial defect models of power transformers were carried out in a laboratory, and the waveform recording method and intelligent sensor proposed were simultaneously used for UHF PD measurement for comparison. The results show that the proposed intelligent sensor is qualified for the UHF PD online monitoring of power transformers. Additionally, three methods to improve the performance of intelligent sensors were proposed according to the principle of the level scanning method.

Linked Learning as a High School Transformation Strategy: Organizational Structures and Leadership Behaviors That Support Lasting Change

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Weiss, Elizabeth Rocio

2016-01-01

Linked Learning is an approach that has proven effective in transforming the learning experiences for high school students. An instrumental case study was conducted in a large urban district in Southern California where district and school leaders implemented Linked Learning as a systemic high school reform initiative. Analysis of the data…

Testing Time and Frequency Fiber-Optic Link Transfer by Hardware Emulation of Acoustic-Band Optical Noise

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Lipiński Marcin

2016-06-01

Full Text Available The low-frequency optical-signal phase noise induced by mechanical vibration of the base occurs in field-deployed fibers. Typical telecommunication data transfer is insensitive to this type of noise but the phenomenon may influence links dedicated to precise Time and Frequency (T&F fiber-optic transfer that exploit the idea of stabilization of phase or propagation delay of the link. To measure effectiveness of suppression of acoustic noise in such a link, a dedicated measurement setup is necessary. The setup should enable to introduce a low-frequency phase corruption to the optical signal in a controllable way. In the paper, a concept of a setup in which the mechanically induced acoustic-band optical signal phase corruption is described and its own features and measured parameters are presented. Next, the experimental measurement results of the T&F transfer TFTS-2 system’s immunity as a function of the fibre-optic length vs. the acoustic-band noise are presented. Then, the dependency of the system immunity on the location of a noise source along the link is also pointed out.

Building Modern Vibration Diagnostics Systems Based on the Frequency-Time Transformations of A Measured Signal

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Yasoveev Vasikh

2016-01-01

Full Text Available Basic methods of analysis of vibration transducers signals were reviewed. Continuous wavelet transform, being a time-frequency transform, was found to be an advanced mathematical tool for analysis of vibration signals. Experimental studies revealed obvious changes in the continuous wavelet transform spectrum depending on the existing defects. A method for detection and identification of technological violations based on the analysis of CWT spectrum components and normalized correlation coefficient was suggested. In accordance with the suggested method software for vibration diagnostics was developed.

Fourier Transform Ion Cyclotron Resonance Mass Spectrometry at the Cyclotron Frequency.

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Nagornov, Konstantin O; Kozhinov, Anton N; Tsybin, Yury O

2017-04-01

The phenomenon of ion cyclotron resonance allows for determining mass-to-charge ratio, m/z, of an ensemble of ions by means of measurements of their cyclotron frequency, ω c . In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the ω c quantity is usually unavailable for direct measurements: the resonant state is located close to the reduced cyclotron frequency (ω + ), whereas the ω c and the corresponding m/z values may be calculated via theoretical derivation from an experimental estimate of the ω + quantity. Here, we describe an experimental observation of a new resonant state, which is located close to the ω c frequency and is established because of azimuthally-dependent trapping electric fields of the recently developed ICR cells with narrow aperture detection electrodes. We show that in mass spectra, peaks close to ω + frequencies can be reduced to negligible levels relative to peaks close to ω c frequencies. Due to reduced errors with which the ω c quantity is obtained, the new resonance provides a means of cyclotron frequency measurements with precision greater than that achieved when ω + frequency peaks are employed. The described phenomenon may be considered for a development into an FT-ICR MS technology with increased mass accuracy for applications in basic research, life, and environmental sciences. Graphical Abstract ᅟ.

Linking transformational leadership to nurses' extra-role performance: the mediating role of self-efficacy and work engagement.

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Salanova, Marisa; Lorente, Laura; Chambel, Maria J; Martínez, Isabel M

2011-10-01

This paper is a report of a social cognitive theory-guided study about the link between supervisors' transformational leadership and staff nurses' extra-role performance as mediated by nurse self-efficacy and work engagement. Past research has acknowledged the positive influence that transformational leaders have on employee (extra-role) performance. However, less is known about the psychological mechanisms that may explain the links between transformational leaders and extra-role performance, which encompasses behaviours that are not considered formal job requirements, but which facilitate the smooth functioning of the organization as a social system. Seventeen supervisors evaluated nurses' extra-role performance, the data generating a sample consisting of 280 dyads. The nurses worked in different health services in a large Portuguese hospital and the participation rate was 76·9% for nurses and 100% for supervisors. Data were collected during 2009. A theory-driven model of the relationships between transformation leadership, self-efficacy, work engagement and nurses' extra-role performance was tested using Structural Equation Modelling. Data analysis revealed a full mediation model in which transformational leadership explained extra-role performance through self-efficacy and work engagement. A direct relationship between transformational leadership and work engagement was also found. Nurses' supervisors with a transformational leadership style enhance different 'extra-role' performance in nurses and this increases hospital efficacy. They do so by establishing a sense of self-efficacy but also by amplifying their levels of engagement in the workplace. © 2011 Blackwell Publishing Ltd.

Comparison of different spatial transformations applied to EEG data: A case study of error processing.

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Cohen, Michael X

2015-09-01

The purpose of this paper is to compare the effects of different spatial transformations applied to the same scalp-recorded EEG data. The spatial transformations applied are two referencing schemes (average and linked earlobes), the surface Laplacian, and beamforming (a distributed source localization procedure). EEG data were collected during a speeded reaction time task that provided a comparison of activity between error vs. correct responses. Analyses focused on time-frequency power, frequency band-specific inter-electrode connectivity, and within-subject cross-trial correlations between EEG activity and reaction time. Time-frequency power analyses showed similar patterns of midfrontal delta-theta power for errors compared to correct responses across all spatial transformations. Beamforming additionally revealed error-related anterior and lateral prefrontal beta-band activity. Within-subject brain-behavior correlations showed similar patterns of results across the spatial transformations, with the correlations being the weakest after beamforming. The most striking difference among the spatial transformations was seen in connectivity analyses: linked earlobe reference produced weak inter-site connectivity that was attributable to volume conduction (zero phase lag), while the average reference and Laplacian produced more interpretable connectivity results. Beamforming did not reveal any significant condition modulations of connectivity. Overall, these analyses show that some findings are robust to spatial transformations, while other findings, particularly those involving cross-trial analyses or connectivity, are more sensitive and may depend on the use of appropriate spatial transformations. Copyright © 2014 Elsevier B.V. All rights reserved.

Frequency of CNKSR2 mutation in the X-linked epilepsy-aphasia spectrum.

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Damiano, John A; Burgess, Rosemary; Kivity, Sara; Lerman-Sagie, Tally; Afawi, Zaid; Scheffer, Ingrid E; Berkovic, Samuel F; Hildebrand, Michael S

2017-03-01

Synaptic proteins are critical to neuronal function in the brain, and their deficiency can lead to seizures and cognitive impairments. CNKSR2 (connector enhancer of KSR2) is a synaptic protein involved in Ras signaling-mediated neuronal proliferation, migration and differentiation. Mutations in the X-linked gene CNKSR2 have been described in patients with seizures and neurodevelopmental deficits, especially those affecting language. In this study, we sequenced 112 patients with phenotypes within the epilepsy-aphasia spectrum (EAS) to determine the frequency of CNKSR2 mutation within this complex set of disorders. We detected a novel nonsense mutation (c.2314 C>T; p.Arg712*) in one Ashkenazi Jewish family, the male proband of which had a severe epileptic encephalopathy with continuous spike-waves in sleep (ECSWS). His affected brother also had ECSWS with better outcome, whereas the sister had childhood epilepsy with centrotemporal spikes. This mutation segregated in the three affected siblings in an X-linked manner, inherited from their mother who had febrile seizures. Although the frequency of point mutation is low, CNKSR2 sequencing should be considered in families with suspected X-linked EAS because of the specific genetic counseling implications. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Reference Beam Pattern Design for Frequency Invariant Beamforming Based on Fast Fourier Transform

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Wang Zhang

2016-09-01

Full Text Available In the field of fast Fourier transform (FFT-based frequency invariant beamforming (FIB, there is still an unsolved problem. That is the selection of the reference beam to make the designed wideband pattern frequency invariant (FI over a given frequency range. This problem is studied in this paper. The research shows that for a given array, the selection of the reference beam pattern is determined by the number of sensors and the ratio of the highest frequency to the lowest frequency of the signal (RHL. The length of the weight vector corresponding to a given reference beam pattern depends on the reference frequency. In addition, the upper bound of the weight length to ensure the FI property over the whole frequency band of interest is also given. When the constraints are added to the reference beam, it does not affect the FI property of the designed wideband beam as long as the symmetry of the reference beam is ensured. Based on this conclusion, a scheme for reference beam design is proposed.

Word frequency effects in immediate serial recall of pure and mixed lists: tests of the associative link hypothesis.

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Saint-Aubin, Jean; LeBlanc, Jacinthe

2005-12-01

In immediate serial recall, high-frequency words are better recalled than low-frequency words. Recently, it has been suggested that high-frequency words are better recalled because of their better long-term associative links, and not because of the intrinsic properties of their long-term representations. In the experiment reported here, recall performance was compared for pure lists of high- and low-frequency words, and for mixed lists composed of either one low- and five high-frequency words or the reverse. The usual advantage of high-frequency words was found with pure lists and this advantage was reduced, but still significant with mixed lists composed of five low-frequency words. However, the low-frequency word included in a high-frequency list was recalled just as well as high-frequency words. Results are challenging for the associative link hypothesis and are best interpreted within an item-based reconstruction hypothesis, along with a distinctiveness account.

Vector frequency-comb Fourier-transform spectroscopy for characterizing metamaterials

International Nuclear Information System (INIS)

Ganz, T; Brehm, M; Von Ribbeck, H G; Keilmann, F; Van der Weide, D W

2008-01-01

We determine infrared transmission amplitude and phase spectra of metamaterial samples at well-defined incidence and polarization with a vector ('asymmetric') frequency-comb Fourier-transform spectrometer (c-FTS) that uses no moving elements. The metamaterials are free-standing metallic hole arrays; we study their resonances in the 7-13 μm and 100-1000 μm wavelength regions due both to interaction with bulk waves (Wood anomaly) and with leaky surface plasmon polaritons (near-unity transmittance, coupling features and dispersion). Such complex-valued transmission and reflection spectra could be used to compute a metamaterial's complex dielectric function directly, as well as its magnetic and magneto-optical permeability functions.

Improving sensitivity of residual current transformers to high frequency earth fault currents

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Czapp Stanislaw

2017-09-01

Full Text Available For protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency earth fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed the modification in the structure of residual current devices. This modification improves sensitivity of residual current devices when high frequency earth fault current occurs. The test of the modified residual current device proved that the authors’ proposition is appropriate.

Ring resonator-based on-chip modulation transformer for high-performance phase-modulated microwave photonic links.

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Zhuang, Leimeng; Taddei, Caterina; Hoekman, Marcel; Leinse, Arne; Heideman, René; van Dijk, Paulus; Roeloffzen, Chris

2013-11-04

In this paper, we propose and experimentally demonstrate a novel wideband on-chip photonic modulation transformer for phase-modulated microwave photonic links. The proposed device is able to transform phase-modulated optical signals into intensity-modulated versions (or vice versa) with nearly zero conversion of laser phase noise to intensity noise. It is constructed using waveguide-based ring resonators, which features simple architecture, stable operation, and easy reconfigurability. Beyond the stand-alone functionality, the proposed device can also be integrated with other functional building blocks of photonic integrated circuits (PICs) to create on-chip complex microwave photonic signal processors. As an application example, a PIC consisting of two such modulation transformers and a notch filter has been designed and realized in TriPleX(TM) waveguide technology. The realized device uses a 2 × 2 splitting circuit and 3 ring resonators with a free spectral range of 25 GHz, which are all equipped with continuous tuning elements. The device can perform phase-to-intensity modulation transform and carrier suppression simultaneously, which enables high-performance phase-modulated microwave photonics links (PM-MPLs). Associated with the bias-free and low-complexity advantages of the phase modulators, a single-fiber-span PM-MPL with a RF bandwidth of 12 GHz (3 dB-suppression band 6 to 18 GHz) has been demonstrated comprising the proposed PIC, where the achieved spurious-free dynamic range performance is comparable to that of Class-AB MPLs using low-biased Mach-Zehnder modulators.

Extremely low frequency magnetic field measurements in buildings with transformer stations in Switzerland.

Science.gov (United States)

Röösli, Martin; Jenni, Daniela; Kheifets, Leeka; Mezei, Gabor

2011-08-15

The aim of this study was to evaluate an exposure assessment method that classifies apartments in three exposure categories of extremely low frequency magnetic fields (ELF-MF) based on the location of the apartment relative to the transformer room. We completed measurements in 39 apartments in 18 buildings. In each room of the apartments ELF-MF was concurrently measured with 5 to 6 EMDEX II meters for 10 min. Measured arithmetic mean ELF-MF was 0.59 μT in 8 apartments that were fully adjacent to a transformer room, either directly above the transformer or touching the transformer room wall-to-wall. In apartments that only partly touched the transformer room at corners or edges, average ELF-MF level was 0.14 μT. Average exposure in the remaining apartments was 0.10 μT. Kappa coefficient for exposure classification was 0.64 (95%-CI: 0.45-0.82) if only fully adjacent apartments were considered as highly exposed (>0.4 μT). We found a distinct ELF-MF exposure gradient in buildings with transformer. Exposure classification based on the location of the apartment relative to the transformer room appears feasible. Such an approach considerably reduces effort for exposure assessment and may be used to eliminate selection bias in future epidemiologic studies. Copyright © 2011 Elsevier B.V. All rights reserved.

[Research of dual-photoelastic-modulator-based beat frequency modulation and Fourier-Bessel transform imaging spectrometer].

Science.gov (United States)

Wang, Zhi-Bin; Zhang, Rui; Wang, Yao-Li; Huang, Yan-Fei; Chen, You-Hua; Wang, Li-Fu; Yang, Qiang

2014-02-01

As the existing photoelastic-modulator(PEM) modulating frequency in the tens of kHz to hundreds of kHz between, leading to frequency of modulated interference signal is higher, so ordinary array detector cannot effectively caprure interference signal..A new beat frequency modulation method based on dual-photoelastic-modulator (Dual-PEM) and Fourier-Bessel transform is proposed as an key component of dual-photoelastic-modulator-based imaging spectrometer (Dual-PEM-IS) combined with charge coupled device (CCD). The dual-PEM are operated as an electro-optic circular retardance modulator, Operating the PEMs at slightly different resonant frequencies w1 and w2 respectively, generates a differential signal at a much lower heterodyne frequency that modulates the incident light. This method not only retains the advantages of the existing PEM, but also the frequency of modulated photocurrent decreased by 2-3 orders of magnitude (10-500 Hz) and can be detected by common array detector, and the incident light spectra can be obtained by Fourier-Bessel transform of low frequency component in the modulated signal. The method makes the PEM has the dual capability of imaging and spectral measurement. The basic principle is introduced, the basic equations is derived, and the feasibility is verified through the corresponding numerical simulation and experiment. This method has' potential applications in imaging spectrometer technology, and analysis of the effect of deviation of the optical path difference. This work provides the necessary theoretical basis for remote sensing of new Dual-PEM-IS and for engineering implementation of spectra inversion.

The space-math link in preschool boys and girls: Importance of mental transformation, targeting accuracy, and spatial anxiety.

Science.gov (United States)

Wong, Wang I

2017-06-01

Spatial abilities are pertinent to mathematical competence, but evidence of the space-math link has largely been confined to older samples and intrinsic spatial abilities (e.g., mental transformation). The roles of gender and affective factors are also unclear. This study examined the correlations between counting ability, mental transformation, and targeting accuracy in 182 Hong Kong preschoolers, and whether these relationships were weaker at higher spatial anxiety levels. Both spatial abilities related with counting similarly for boys and girls. Targeting accuracy also mediated the male advantage in counting. Interestingly, spatial anxiety moderated the space-math links, but differently for boys and girls. For boys, spatial abilities were irrelevant to counting at high anxiety levels; for girls, the role of anxiety on the space-math link is less clear. Results extend the evidence base of the space-math link to include an extrinsic spatial ability (targeting accuracy) and have implications for intervention programmes. Statement of contribution What is already known on this subject? Much evidence of a space-math link in adolescent and adult samples and for intrinsic spatial abilities. What does this study add? Extended the space-math link to include both intrinsic and extrinsic spatial abilities in a preschool sample. Showed how spatial anxiety moderated the space-math link differently for boys and girls. © 2016 The British Psychological Society.

A Radio-Frequency-over-Fiber link for large-array radio astronomy applications

International Nuclear Information System (INIS)

Mena, J; Bandura, K; Cliche, J-F; Dobbs, M; Gilbert, A; Tang, Q Y

2013-01-01

A prototype 425-850 MHz Radio-Frequency-over-Fiber (RFoF) link for the Canadian Hydrogen Intensity Mapping Experiment (CHIME) is presented. The design is based on a directly modulated Fabry-Perot (FP) laser, operating at ambient temperature, and a single-mode fiber. The dynamic performance, gain stability, and phase stability of the RFoF link are characterized. Tests on a two-element interferometer built at the Dominion Radio Astrophysical Observatory for CHIME prototyping demonstrate that RFoF can be successfully used as a cost-effective solution for analog signal transport on the CHIME telescope and other large-array radio astronomy applications

Off-resonance frequency operation for power transfer in a loosely coupled air core transformer

Science.gov (United States)

Scudiere, Matthew B

2012-11-13

A power transmission system includes a loosely coupled air core transformer having a resonance frequency determined by a product of inductance and capacitance of a primary circuit including a primary coil. A secondary circuit is configured to have a substantially same product of inductance and capacitance. A back EMF generating device (e.g., a battery), which generates a back EMF with power transfer, is attached to the secondary circuit. Once the load power of the back EMF generating device exceeds a certain threshold level, which depends on the system parameters, the power transfer can be achieved at higher transfer efficiency if performed at an operating frequency less than the resonance frequency, which can be from 50% to 95% of the resonance frequency.

Filter frequency response of time dependent signal using Laplace transform

Energy Technology Data Exchange (ETDEWEB)

Shestakov, Aleksei I. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2018-01-16

We analyze the effect a filter has on a time dependent signal x(t). If X(s) is the Laplace transform of x and H (s) is the filter Transfer function, the response in frequency space is X (s) H (s). Consequently, in real space, the response is the convolution (x*h) (t), where hi is the Laplace inverse of H. Effects are analyzed and analytically for functions such as (t/t_c)² e^-t/t$_c$, where t_c = const. We consider lowpass, highpass and bandpass filters.

A Fast Hartley Transform based novel optical OFDM system for VLC indoor application with constant envelope PAPR reduction technique using frequency modulation

Science.gov (United States)

Singh, Vinay Kumar; Dalal, U. D.

2017-10-01

In this research literature we present a unique optical OFDM system for Visible Light Communication (VLC) intended for indoor application which uses a non conventional transform-Fast Hartley Transform and an effective method to reduce the peak to average power ratio (PAPR) of the OFDM signal based on frequency modulation leading to a constant envelope (CE) signal. The proposed system is analyzed by a complete mathematical model and verified by the concurrent simulations results. The use of the non conventional transform makes the system computationally more desirable as it does not require the Hermitian symmetry constraint to yield real signals. The frequency modulation of the baseband signal converge random peaks into a CE signal. This leads to alleviation of the non linearity effects of the LED used in the link for electrical to optical conversion. The PAPR is reduced to 2 dB by this technique in this work. The impact of the modulation index on the performance of the system is also investigated. An optimum modulation depth of 30% gives better results. The additional phase discontinuity incurring on the demodulated signal at the receiver is also significantly reduced. A comparison of the improvement in phase discontinuity of the proposed technique of combating the PAPR with the previously known phase modulation technique is also presented in this work. Based on the channel metrics we evaluate the system performance and report an improvement of 1.2 dB at the FEC threshold. The proposed system is simple in design and computationally efficient and this can be incorporated into the present VLC system without much alteration thereby making it a cost effective solution.

An improved partially interleaved transformer structure for high-voltage high-frequency multiple-output applications

DEFF Research Database (Denmark)

Zhao, Bin; Ouyang, Ziwei; Andersen, Michael A. E.

2017-01-01

. The proposed structure features lower leakage inductance, smaller AC capacitance and lower rate of AC-DC resistance, which is suitable for high-frequency high-efficiency applications. A planar transformer with the proposed structure was built and tested in an LCLC resonant converter, where the input voltage...

Non-contact radio frequency shielding and wave guiding by multi-folded transformation optics method.

Science.gov (United States)

Madni, Hamza Ahmad; Zheng, Bin; Yang, Yihao; Wang, Huaping; Zhang, Xianmin; Yin, Wenyan; Li, Erping; Chen, Hongsheng

2016-11-14

Compared with conventional radio frequency (RF) shielding methods in which the conductive coating material encloses the circuits design and the leakage problem occurs due to the gap in such conductive material, non-contact RF shielding at a distance is very promising but still impossible to achieve so far. In this paper, a multi-folded transformation optics method is proposed to design a non-contact device for RF shielding. This "open-shielded" device can shield any object at a distance from the electromagnetic waves at the operating frequency, while the object is still physically open to the outer space. Based on this, an open-carpet cloak is proposed and the functionality of the open-carpet cloak is demonstrated. Furthermore, we investigate a scheme of non-contact wave guiding to remotely control the propagation of surface waves over any obstacles. The flexibilities of such multi-folded transformation optics method demonstrate the powerfulness of the method in the design of novel remote devices with impressive new functionalities.

Calculation of core loss and copper loss in amorphous/nanocrystalline core-based high-frequency transformer

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Xiaojing Liu

2016-05-01

Full Text Available Amorphous and nanocrystalline alloys are now widely used for the cores of high-frequency transformers, and Litz-wire is commonly used as the windings, while it is difficult to calculate the resistance accurately. In order to design a high-frequency transformer, it is important to accurately calculate the core loss and copper loss. To calculate the core loss accurately, the additional core loss by the effect of end stripe should be considered. It is difficult to simulate the whole stripes in the core due to the limit of computation, so a scale down model with 5 stripes of amorphous alloy is simulated by the 2D finite element method (FEM. An analytical model is presented to calculate the copper loss in the Litz-wire, and the results are compared with the calculations by FEM.

Leading High School Transformation for College and Career Success: A Guide for Developing a System of Linked Learning Pathways

Science.gov (United States)

Stearns, Roman

2014-01-01

This ConnectEd Guide for Developing a System of Linked Learning Pathways will introduce school district leaders and their community partners to Linked Learning and a system of quality pathways that can transform high schools, instructional practice, and the student experience. Not intended to be prescriptive, this document can and should be…

A time-frequency analysis method to obtain stable estimates of magnetotelluric response function based on Hilbert-Huang transform

Science.gov (United States)

Cai, Jianhua

2017-05-01

The time-frequency analysis method represents signal as a function of time and frequency, and it is considered a powerful tool for handling arbitrary non-stationary time series by using instantaneous frequency and instantaneous amplitude. It also provides a possible alternative to the analysis of the non-stationary magnetotelluric (MT) signal. Based on the Hilbert-Huang transform (HHT), a time-frequency analysis method is proposed to obtain stable estimates of the magnetotelluric response function. In contrast to conventional methods, the response function estimation is performed in the time-frequency domain using instantaneous spectra rather than in the frequency domain, which allows for imaging the response parameter content as a function of time and frequency. The theory of the method is presented and the mathematical model and calculation procedure, which are used to estimate response function based on HHT time-frequency spectrum, are discussed. To evaluate the results, response function estimates are compared with estimates from a standard MT data processing method based on the Fourier transform. All results show that apparent resistivities and phases, which are calculated from the HHT time-frequency method, are generally more stable and reliable than those determined from the simple Fourier analysis. The proposed method overcomes the drawbacks of the traditional Fourier methods, and the resulting parameter minimises the estimation bias caused by the non-stationary characteristics of the MT data.

Warped frequency transform analysis of ultrasonic guided waves in long bones

Science.gov (United States)

De Marchi, L.; Baravelli, E.; Xu, K.; Ta, D.; Speciale, N.; Marzani, A.; Viola, E.

2010-03-01

Long bones can be seen as irregular hollow tubes, in which, for a given excitation frequency, many ultrasonic Guided Waves (GWs) can propagate. The analysis of GWs is potential to reflect more information on both geometry and material properties of the bone than any other method (such as dual-energy X-ray absorptiometry, or quantitative computed tomography), and can be used in the assessment of osteoporosis and in the evaluation of fracture healing. In this study, time frequency representations (TFRs) were used to gain insights into the expected behavior of GWs in bones. To this aim, we implemented a dedicated Warped Frequency Transform (WFT) which decomposes the spectrotemporal components of the different propagating modes by selecting an appropriate warping map to reshape the frequency axis. The map can be designed once the GWs group velocity dispersion curves can be predicted. To this purpose, the bone is considered as a hollow cylinder with inner and outer diameter of 16.6 and 24.7 mm, respectively, and linear poroelastic material properties in agreement with the low level of stresses induced by the waves. Timetransient events obtained experimentally, via a piezoelectric ultrasonic set-up applied to bovine tibiae, are analyzed. The results show that WFT limits interference patterns which appear with others TFRs (such as scalograms or warpograms) and produces a sparse representation suitable for characterization purposes. In particular, the mode-frequency combinations propagating with minimal losses are identified.

Limitations in distance and frequency due to chromatic dispersion in fibre-optic microwave and millimeter-wave links

DEFF Research Database (Denmark)

Gliese, Ulrik Bo; Nielsen, Søren Nørskov; Nielsen, Søren Nørskov

1996-01-01

Chromatic dispersion significantly limits the distance and/or frequency in fibre-optic microwave and millimeter-wave links based on direct detection due to a decrease of the carrier to noise ratio. The limitations in links based on coherent remote heterodyne detection, however, are far less...

Mesoscale models for stacking faults, deformation twins and martensitic transformations: Linking atomistics to continuum

Science.gov (United States)

Kibey, Sandeep A.

We present a hierarchical approach that spans multiple length scales to describe defect formation---in particular, formation of stacking faults (SFs) and deformation twins---in fcc crystals. We link the energy pathways (calculated here via ab initio density functional theory, DFT) associated with formation of stacking faults and twins to corresponding heterogeneous defect nucleation models (described through mesoscale dislocation mechanics). Through the generalized Peieirls-Nabarro model, we first correlate the width of intrinsic SFs in fcc alloy systems to their nucleation pathways called generalized stacking fault energies (GSFE). We then establish a qualitative dependence of twinning tendency in fee metals and alloys---specifically, in pure Cu and dilute Cu-xAl (x= 5.0 and 8.3 at.%)---on their twin-energy pathways called the generalized planar fault energies (GPFE). We also link the twinning behavior of Cu-Al alloys to their electronic structure by determining the effect of solute Al on the valence charge density redistribution at the SF through ab initio DFT. Further, while several efforts have been undertaken to incorporate twinning for predicting stress-strain response of fcc materials, a fundamental law for critical twinning stress has not yet emerged. We resolve this long-standing issue by linking quantitatively the twin-energy pathways (GPFE) obtained via ab initio DFT to heterogeneous, dislocation-based twin nucleation models. We establish an analytical expression that quantitatively predicts the critical twinning stress in fcc metals in agreement with experiments without requiring any empiricism at any length scale. Our theory connects twinning stress to twin-energy pathways and predicts a monotonic relation between stress and unstable twin stacking fault energy revealing the physics of twinning. We further demonstrate that the theory holds for fcc alloys as well. Our theory inherently accounts for directional nature of twinning which available

Time-frequency analysis of fusion plasma signals beyond the short-time Fourier transform paradigm: An overview

International Nuclear Information System (INIS)

Bizarro, Joao P.S.; Figueiredo, Antonio C.A.

2008-01-01

Performing a time-frequency (t-f) analysis on actual magnetic pick-up coil data from the JET tokamak, a comparison is presented between the spectrogram and the Wigner and Choi-Williams distributions. Whereas the former, which stems from the short-time Fourier transform and has been the work-horse for t-f signal processing, implies an unavoidable trade-off between time and frequency resolutions, the latter two belong to a later generation of distributions that yield better, if not optimal joint t-f localization. Topics addressed include signal representation in the t-f plane, frequency identification and evolution, instantaneous-frequency estimation, and amplitude tracking

Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

Energy Technology Data Exchange (ETDEWEB)

Hu, M.; Bai, Y. Z., E-mail: abai@mail.hust.edu.cn; Zhou, Z. B., E-mail: zhouzb@mail.hust.edu.cn; Li, Z. X.; Luo, J. [MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

2014-05-15

The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided.

Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

International Nuclear Information System (INIS)

Hu, M.; Bai, Y. Z.; Zhou, Z. B.; Li, Z. X.; Luo, J.

2014-01-01

The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided

Performance Evaluation of Frequency Transform Based Block Classification of Compound Image Segmentation Techniques

Science.gov (United States)

Selwyn, Ebenezer Juliet; Florinabel, D. Jemi

2018-04-01

Compound image segmentation plays a vital role in the compression of computer screen images. Computer screen images are images which are mixed with textual, graphical, or pictorial contents. In this paper, we present a comparison of two transform based block classification of compound images based on metrics like speed of classification, precision and recall rate. Block based classification approaches normally divide the compound images into fixed size blocks of non-overlapping in nature. Then frequency transform like Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT) are applied over each block. Mean and standard deviation are computed for each 8 × 8 block and are used as features set to classify the compound images into text/graphics and picture/background block. The classification accuracy of block classification based segmentation techniques are measured by evaluation metrics like precision and recall rate. Compound images of smooth background and complex background images containing text of varying size, colour and orientation are considered for testing. Experimental evidence shows that the DWT based segmentation provides significant improvement in recall rate and precision rate approximately 2.3% than DCT based segmentation with an increase in block classification time for both smooth and complex background images.

On the Link Between Benevolent Sexism and Orgasm Frequency in Heterosexual Women.

Science.gov (United States)

Harris, Emily Ann; Hornsey, Matthew J; Barlow, Fiona Kate

2016-11-01

Previous research on subclinical orgasmic difficulties among women has focused on intrapsychic and interpersonal variables, but little attention has been paid to the more distal ideological factors that might indirectly constrain sexual pleasure. We hypothesized that women's endorsement of a benevolently sexist worldview would be negatively associated with orgasm frequency. Specifically, we predicted that benevolent sexism would be associated with increased perceptions of male sexual selfishness. This perception of men as interested in their own sexual pleasure would then predict decreased willingness to ask a partner for sexual pleasure, which in turn would be associated with less frequent orgasms. We found support for our model across two studies (Study 1: N = 339; Study 2: N = 323). We did not, however, find a direct effect of benevolent sexism on orgasm frequency. We discuss possible additional variables linking benevolent sexism with orgasm frequency, implications, and future directions.

A Novel Application of Fourier Transform Spectroscopy with HEMT Amplifiers at Microwave Frequencies

Science.gov (United States)

Wilkinson, David T.; Page, Lyman

1995-01-01

The goal was to develop cryogenic high-electron-mobility transistor (HEMT) based radiometers and use them to measure the anisotropy in the cosmic microwave background (CMB). In particular, a novel Fourier transform spectrometer (FTS) built entirely of waveguide components would be developed. A dual-polarization Ka-band HEMT radiometer and a similar Q-band radiometer were built. In a series of measurements spanning three years made from a ground-based site in Saskatoon, SK, the amplitude, frequency spectrum, and spatial frequency spectrum of the anisotropy were measured. A prototype Ka-band FTS was built and tested, and a simplified version is proposed for the MAP satellite mission. The 1/f characteristics of HEMT amplifiers were quantified using correlation techniques.

High-precision terahertz frequency modulated continuous wave imaging method using continuous wavelet transform

Science.gov (United States)

Zhou, Yu; Wang, Tianyi; Dai, Bing; Li, Wenjun; Wang, Wei; You, Chengwu; Wang, Kejia; Liu, Jinsong; Wang, Shenglie; Yang, Zhengang

2018-02-01

Inspired by the extensive application of terahertz (THz) imaging technologies in the field of aerospace, we exploit a THz frequency modulated continuous-wave imaging method with continuous wavelet transform (CWT) algorithm to detect a multilayer heat shield made of special materials. This method uses the frequency modulation continuous-wave system to catch the reflected THz signal and then process the image data by the CWT with different basis functions. By calculating the sizes of the defects area in the final images and then comparing the results with real samples, a practical high-precision THz imaging method is demonstrated. Our method can be an effective tool for the THz nondestructive testing of composites, drugs, and some cultural heritages.

Time-frequency analysis of phonocardiogram signals using wavelet transform: a comparative study.

Science.gov (United States)

Ergen, Burhan; Tatar, Yetkin; Gulcur, Halil Ozcan

2012-01-01

Analysis of phonocardiogram (PCG) signals provides a non-invasive means to determine the abnormalities caused by cardiovascular system pathology. In general, time-frequency representation (TFR) methods are used to study the PCG signal because it is one of the non-stationary bio-signals. The continuous wavelet transform (CWT) is especially suitable for the analysis of non-stationary signals and to obtain the TFR, due to its high resolution, both in time and in frequency and has recently become a favourite tool. It decomposes a signal in terms of elementary contributions called wavelets, which are shifted and dilated copies of a fixed mother wavelet function, and yields a joint TFR. Although the basic characteristics of the wavelets are similar, each type of the wavelets produces a different TFR. In this study, eight real types of the most known wavelets are examined on typical PCG signals indicating heart abnormalities in order to determine the best wavelet to obtain a reliable TFR. For this purpose, the wavelet energy and frequency spectrum estimations based on the CWT and the spectra of the chosen wavelets were compared with the energy distribution and the autoregressive frequency spectra in order to determine the most suitable wavelet. The results show that Morlet wavelet is the most reliable wavelet for the time-frequency analysis of PCG signals.

Wireless transmission of power and information through one high frequency resonant AC link inverter for robot manipulator applications

International Nuclear Information System (INIS)

Kawamura, Atsuo; Ishioka, Kazuaki; Hirai, Junji.

1995-01-01

A contact-less decentralized power supply is proposed with communication capability through only one transformer. A prototype of wireless transmission system of power and information (WTPI system) was built, and the two axis position control for servo motors was achieved by transferring the power and signal through one rotatable high frequency transformer. The proposed concept can be applied for robotics and NC machines

Modification of radiation-induced sex-linked recessive lethal mutation frequency by tocopherol

International Nuclear Information System (INIS)

Beckman, C.; Roy, R.M.; Sproule, A.

1982-01-01

The present study evaluates the effect of supplementing culture medium with α-tocopherol acetate on the yield of sex-linked recessive lethal mutants induced by X-irradiation in mature sperm of Drosophila. Although tocopherol treatment of males had no impact on the yield of mutations, a drastic reduction in mutation frequency was observed when irradiated males were mated to females raised and subsequently maintained on tocopherol-enriched diet. (orig./MG)

Wavelet-transform-based time–frequency domain reflectometry for reduction of blind spot

International Nuclear Information System (INIS)

Lee, Sin Ho; Park, Jin Bae; Choi, Yoon Ho

2012-01-01

In this paper, wavelet-transform-based time–frequency domain reflectometry (WTFDR) is proposed to reduce the blind spot in reflectometry. TFDR has a blind spot problem when the time delay between the reference signal and the reflected signal is short enough compared with the time duration of the reference signal. To solve the blind spot problem, the wavelet transform (WT) is used because the WT has linearity. Using the characteristics of the WT, the overlapped reference signal at the measured signal can be separated and the blind spot is reduced by obtaining the difference of the wavelet coefficients for the reference and reflected signals. In the proposed method, the complex wavelet is utilized as a mother wavelet because the reference signal in WTFDR has a complex form. Finally, the computer simulations and the real experiments are carried out to confirm the effectiveness and accuracy of the proposed method. (paper)

On the determination of the dynamic properties of a transformer oil based ferrofluid in the frequency range 0.1–20 GHz

International Nuclear Information System (INIS)

Fannin, P.C.; Vekas, L.; Marin, C.N.; Malaescu, I.

2017-01-01

Complex susceptibility measurements provide a unique and efficient means for the investigation and determination of the dynamic properties of magnetic fluids. In particular, measurement of the frequency, f(Hz), and field, H(kA/m), dependent, complex susceptibility, χ(ω, Η)= χ′(ω, Η)−iχ″(ω, Η), of magnetic fluids has proven to be a valuable and reliable technique for investigating such properties. The experimental data presented here was obtained from measurements of a transformer oil based ferrofluid, with measurements being performed over the frequency range 0.1–20 GHz and polarising fields 0–168 kA/m. In the case of transformer oil magnetic fluids, the normal measurement emphasis has been on the investigation of their dielectric properties, including the effects which lightning may have on these properties. Little has been reported on the measurement of the corresponding magnetic susceptibility, χ(ω), of such fluids and in this paper we address this fact. Thus we consider it worthwhile, in the case of a transformer with magnetic fluid transformer oil, being affected as a result of a lightening occurrence, to have knowledge of the fluids dynamic properties, at the microwave frequencies. In the process of determining the sample susceptibility profiles, it was found that the peak value of the χ″(ω) component, was approximately constant over the frequency range 2.4–6.3 GHz. From this it was determined that the fluid was effectively operating as a wideband absorber over a bandwidth of 3.9 GHz. - Highlights: • Complex magnetic susceptibility measurements in the frequency range 0.1–20 GHz. • Determination of the dynamic properties of a transformer oil based ferrofluid. • Wideband attenuator ( Absorber) in the frequency range 2.4–6.3 GHz.

Simultaneously precise frequency transfer and time synchronization using feed-forward compensation technique via 120 km fiber link.

Science.gov (United States)

Chen, Xing; Lu, Jinlong; Cui, Yifan; Zhang, Jian; Lu, Xing; Tian, Xusheng; Ci, Cheng; Liu, Bo; Wu, Hong; Tang, Tingsong; Shi, Kebin; Zhang, Zhigang

2015-12-22

Precision time synchronization between two remote sites is desired in many applications such as global positioning satellite systems, long-baseline interferometry, coherent radar detection and fundamental physics constant measurements. The recently developed frequency dissemination technologies based on optical fiber link have improved the transfer instability to the level of 10(-19)/day at remote location. Therefore it is possible to keep clock oscillation at remote locations continuously corrected, or to reproduce a "virtual" clock on the remote location. However the initial alignment and the correction of 1 pps timing signal from time to time are still required, besides the highly stabilized clock frequency transfer between distant locations. Here we demonstrate a time synchronization based on an ultra-stable frequency transfer system via 120-km commercial fiber link by transferring an optical frequency comb. Both the phase noise compensation in frequency dissemination and temporal basis alignment in time synchronization were implemented by a feed-forward digital compensation (FFDC) technique. The fractional frequency instability was measured to be 6.18 × 10(-20) at 2000 s. The timing deviation of time synchronization was measured to be 0.6 ps in 1500 s. This technique also can be applied in multi-node fiber network topology.

Broadband W-band Rapid Frequency Sweep Considerations for Fourier Transform EPR.

Science.gov (United States)

Strangeway, Robert A; Hyde, James S; Camenisch, Theodore G; Sidabras, Jason W; Mett, Richard R; Anderson, James R; Ratke, Joseph J; Subczynski, Witold K

2017-12-01

A multi-arm W-band (94 GHz) electron paramagnetic resonance spectrometer that incorporates a loop-gap resonator with high bandwidth is described. A goal of the instrumental development is detection of free induction decay following rapid sweep of the microwave frequency across the spectrum of a nitroxide radical at physiological temperature, which is expected to lead to a capability for Fourier transform electron paramagnetic resonance. Progress toward this goal is a theme of the paper. Because of the low Q-value of the loop-gap resonator, it was found necessary to develop a new type of automatic frequency control, which is described in an appendix. Path-length equalization, which is accomplished at the intermediate frequency of 59 GHz, is analyzed. A directional coupler is favored for separation of incident and reflected power between the bridge and the loop-gap resonator. Microwave leakage of this coupler is analyzed. An oversize waveguide with hyperbolic-cosine tapers couples the bridge to the loop-gap resonator, which results in reduced microwave power and signal loss. Benchmark sensitivity data are provided. The most extensive application of the instrument to date has been the measurement of T 1 values using pulse saturation recovery. An overview of that work is provided.

The Quality and Frequency of Mother-Toddler Conflict: Links with Attachment and Temperament

Science.gov (United States)

Laible, Deborah; Panfile, Tia; Makariev, Drika

2008-01-01

The goal of this study was to examine the links among attachment, child temperament, and the quality and frequency of mother-toddler conflict. Sixty-four mothers and children took part in a series of laboratory tasks when the child was 30 months of age and an audio-recorded home observation when the child was 36 months of age. All episodes of…

Characterization of In-Body to On-Body Wireless Radio Frequency Link for Upper Limb Prostheses.

Directory of Open Access Journals (Sweden)

Antonietta Stango

Full Text Available Wireless implanted devices can be used to interface patients with disabilities with the aim of restoring impaired motor functions. Implanted devices that record and transmit electromyographic (EMG signals have been applied for the control of active prostheses. This simulation study investigates the propagation losses and the absorption rate of a wireless radio frequency link for in-to-on body communication in the medical implant communication service (MICS frequency band to control myoelectric upper limb prostheses. The implanted antenna is selected and a suitable external antenna is designed. The characterization of both antennas is done by numerical simulations. A heterogeneous 3D body model and a 3D electromagnetic solver have been used to model the path loss and to characterize the specific absorption rate (SAR. The path loss parameters were extracted and the SAR was characterized, verifying the compliance with the guideline limits. The path loss model has been also used for a preliminary link budget analysis to determine the feasibility of such system compliant with the IEEE 802.15.6 standard. The resulting link margin of 11 dB confirms the feasibility of the system proposed.

Frequency-division multiplexer and demultiplexer for terahertz wireless links.

Science.gov (United States)

Ma, Jianjun; Karl, Nicholas J; Bretin, Sara; Ducournau, Guillaume; Mittleman, Daniel M

2017-09-28

The development of components for terahertz wireless communications networks has become an active and growing research field. However, in most cases these components have been studied using a continuous or broadband-pulsed terahertz source, not using a modulated data stream. This limitation may mask important aspects of the performance of the device in a realistic system configuration. We report the characterization of one such device, a frequency multiplexer, using modulated data at rates up to 10 gigabits per second. We also demonstrate simultaneous error-free transmission of two signals at different carrier frequencies, with an aggregate data rate of 50 gigabits per second. We observe that the far-field spatial variation of the bit error rate is different from that of the emitted power, due to a small nonuniformity in the angular detection sensitivity. This is likely to be a common feature of any terahertz communication system in which signals propagate as diffracting beams not omnidirectional broadcasts.There is growing interest in the development of components to facilitate wireless communications in the terahertz but the characterization of these systems involve an unmodulated input. Here the authors demonstrate multiplexing and demultiplexing of data streams in the terahertz range using a real data link.

Electronic Power Transformer for Power Distribution Networks

Directory of Open Access Journals (Sweden)

Ermuraсhi Iu.V.

2017-12-01

Full Text Available Reducing losses in electricity distribution networks is a current technical problem. This issue also has social and environmental aspects. As a promising solution one can examine the direct distribution from the medium voltage power network using new equipment based on the use of power electronics. The aim of the paper is to propose and argue an innovative technical solution for the realization of the Solid State Transformer (SST in order to decrease the number of energy transformation stages compared to the known solutions, simplifying the topology of the functional scheme with the reduction of production costs and the loss of energy in transformers used in electrical distribution networks. It is proposed the solution of simplifying the topology of the AC/AC electronic transformer by reducing the number of passive electronic components (resistors, inductors, capacitors and active (transistors. The inverter of the SST transformer ensures the switching mode of the transistors, using for this purpose the inductance of the magnetic leakage flux of the high frequency transformer. The robustness of the laboratory sample of the SST 10 / 0.22 kV transformer with the power of 20 kW was manufactured and tested. Testing of the laboratory sample confirmed the functionality of the proposed scheme and the possibility of switching of the transistors to at zero current (ZCS mode with the reduction of the energy losses. In the proposed converter a single high-frequency transformer with a simplified construction with two windings is used, which reduces its mass and the cost of making the transformer. The reduction in the manufacturing cost of the converter is also due to the decrease in the number of links between the functional elements.

Quasi-static analysis of flexible pavements based on predicted frequencies using Fast Fourier Transform and Artificial Neural Network

Directory of Open Access Journals (Sweden)

Ali Reza Ghanizadeh

2018-01-01

Full Text Available New trend in design of flexible pavements is mechanistic-empirical approach. The first step for applying this method is analyzing the pavement structure for several times and computation of critical stresses and strains, which needs a fast analysis method with good accuracy. This paper aims to introduce a new rapid pavement analysis approach, which can consider the history of loading and rate effect. To this end, 1200 flexible pavement sections were analyzed, and equivalent frequencies (EF were calculated using Fast Fourier Transform (FFT method at various depths of asphalt layer. A nonlinear regression equation has been presented for determining EF at different depths of asphalt layer. For more accurate predicting of EF at low frequencies, a feed-forward Artificial Neural Network (ANN was employed, which allows accurate prediction of EF. The frequencies obtained by the proposed regression equation and ANN were compared with frequencies observed in Virginia Smart Road project, and it was found that there is a good agreement between observed and predicted frequencies. Comparison of quasi-static analysis of flexible pavements by frequencies obtained using FFT method and full dynamic analysis by 3D-Move program approves that the critical responses of pavement computed by proposed quasi-static analysis approach are comparable to critical responses computed using full dynamic analysis. Keywords: Equivalent frequency, Fast Fourier Transform (FFT, Pavement quasi-static analysis, Dynamic modulus, Artificial Neural Network (ANN

DC-DC Type High-Frequency Link DC for Improved Power Quality of Cascaded Multilevel Inverter

Science.gov (United States)

Sadikin, Muhammad; Senjyu, Tomonobu; Yona, Atsushi

2013-06-01

Multilevel inverters are emerging as a new breed of power converter options for power system applications. Recent advances in power switching devices enabled the suitability of multilevel inverters for high voltage and high power applications because they are connecting several devices in series without the need of component matching. Usually, a transformerless battery energy storage system, based on a cascaded multilevel inverter, is used as a measure for voltage and frequency deviations. System can be reduced in size, weight, and cost of energy storage system. High-frequency link circuit topology is advantageous in realizing compact and light-weight power converters for uninterruptible power supply systems, new energy systems using photovoltaic-cells, fuel-cells and so on. This paper presents a DC-DC type high-frequency link DC (HFLDC) cascaded multilevel inverter. Each converter cell is implemented a control strategy for two H-bridge inverters that are controlled with the same multicarrier pulse width modulation (PWM) technique. The proposed cascaded multilevel inverter generates lower voltage total harmonic distortion (THD) in comparison with conventional cascaded multilevel inverter. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of the proposed cascaded multilevel inverter.

Matrix attachment regions (MARs) enhance transformation frequencies and reduce variance of transgene expression in barley

DEFF Research Database (Denmark)

Petersen, K.; Leah, R.; Knudsen, S.

2002-01-01

-MAR from petunia revealed that only the P1-MAR had specific binding affinity for barley nuclear matrices. The barley transformation frequency with the uidA reporter gene was increased 2-fold when the gene was flanked with either the P1-MAR or TBS-MAR, while the gene copy number was strongly reduced...

Linking Transformational Leadership, Absorptive Capacity, and Corporate Entrepreneurship

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Imran Shafique

2018-03-01

Full Text Available This study aims to analyze the nexus between transformational leadership and corporate entrepreneurship through an integration of dispersed scholarly work on transformational leadership, absorptive capacity, and corporate entrepreneurship under one framework. A survey method was employed for the collection of data from small and medium-sized enterprises (SMEs of Pakistan. The data were analyzed using structural equation modeling (SEM technique to empirically test the hypotheses. The results demonstrate that transformational leadership positively affects corporate entrepreneurship and its dimensions—namely, innovation, new business venturing, self-renewal, proactivity, and risk-taking—both directly and through absorptive capacity. The potential of transformational leadership to influence corporate entrepreneurship via absorptive capacity added additional interesting substitutes. Future studies may produce novel insights by examining different leadership styles, settings, or utilizing qualitative technique. Firms should invest to initiate transformational leadership training programs for their managers. Additionally, if these firms are aiming to promote corporate entrepreneurship, they should focus on hiring managers that have attributes of transformational leadership. Furthermore, they should also invest in absorptive capacity to utilize outside knowledge for the enhancement of entrepreneurial activities. This study exploits research work on the relationship between transformational leadership and corporate entrepreneurship in a novel way; it investigates the dimensions of entrepreneurship individually, as well as unidimensionally, and includes the mediating role of absorptive capacity and tests several other hypotheses that previously have been ignored. This study, compared to the existing research, contributes to the impact of transformational leadership on corporate entrepreneurship and absorptive capacity, especially in Pakistan�

Phase information of time-frequency transforms as a key feature for classification of atrial fibrillation episodes

International Nuclear Information System (INIS)

Ortigosa, Nuria; Fernández, Carmen; Galbis, Antonio; Cano, Óscar

2015-01-01

Patients suffering from atrial fibrillation can be classified into different subtypes, according to the temporal pattern of the arrhythmia and its recurrence. Nowadays, clinicians cannot differentiate a priori between the different subtypes, and patient classification is done afterwards, when its clinical course is available. In this paper we present a comparison of classification performances when differentiating paroxysmal and persistent atrial fibrillation episodes by means of support vector machines. We analyze short surface electrocardiogram recordings by extracting modulus and phase features from several time-frequency transforms: short-time Fourier transform, Wigner–Ville, Choi–Williams, Stockwell transform, and general Fourier-family transform. Overall, accuracy higher than 81% is obtained when classifying phase information features of real test ECGs from a heterogeneous cohort of patients (in terms of progression of the arrhythmia and antiarrhythmic treatment) recorded in a tertiary center. Therefore, phase features can facilitate the clinicians’ choice of the most appropriate treatment for each patient by means of a non-invasive technique (the surface ECG). (paper)

Additive effects of word frequency and stimulus quality: the influence of trial history and data transformations.

Science.gov (United States)

Balota, David A; Aschenbrenner, Andrew J; Yap, Melvin J

2013-09-01

A counterintuitive and theoretically important pattern of results in the visual word recognition literature is that both word frequency and stimulus quality produce large but additive effects in lexical decision performance. The additive nature of these effects has recently been called into question by Masson and Kliegl (in press), who used linear mixed effects modeling to provide evidence that the additive effects were actually being driven by previous trial history. Because Masson and Kliegl also included semantic priming as a factor in their study and recent evidence has shown that semantic priming can moderate the additivity of word frequency and stimulus quality (Scaltritti, Balota, & Peressotti, 2012), we reanalyzed data from 3 published studies to determine if previous trial history moderated the additive pattern when semantic priming was not also manipulated. The results indicated that previous trial history did not influence the joint influence of word frequency and stimulus quality. More important, and independent of Masson and Kliegl's conclusions, we also show how a common transformation used in linear mixed effects analyses to normalize the residuals can systematically alter the way in which two variables combine to influence performance. Specifically, using transformed, rather than raw reaction times, consistently produces more underadditive patterns. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Power Electronic Transformer based Three-Phase PWM AC Drives

Science.gov (United States)

Basu, Kaushik

A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common

HTLV-1 tax stabilizes MCL-1 via TRAF6-dependent K63-linked polyubiquitination to promote cell survival and transformation.

Directory of Open Access Journals (Sweden)

Young Bong Choi

2014-10-01

Full Text Available The human T-cell leukemia virus type 1 (HTLV-1 Tax protein hijacks the host ubiquitin machinery to activate IκB kinases (IKKs and NF-κB and promote cell survival; however, the key ubiquitinated factors downstream of Tax involved in cell transformation are unknown. Using mass spectrometry, we undertook an unbiased proteome-wide quantitative survey of cellular proteins modified by ubiquitin in the presence of Tax or a Tax mutant impaired in IKK activation. Tax induced the ubiquitination of 22 cellular proteins, including the anti-apoptotic BCL-2 family member MCL-1, in an IKK-dependent manner. Tax was found to promote the nondegradative lysine 63 (K63-linked polyubiquitination of MCL-1 that was dependent on the E3 ubiquitin ligase TRAF6 and the IKK complex. Tax interacted with and activated TRAF6, and triggered its mitochondrial localization, where it conjugated four carboxyl-terminal lysine residues of MCL-1 with K63-linked polyubiquitin chains, which stabilized and protected MCL-1 from genotoxic stress-induced degradation. TRAF6 and MCL-1 played essential roles in the survival of HTLV-1 transformed cells and the immortalization of primary T cells by HTLV-1. Therefore, K63-linked polyubiquitination represents a novel regulatory mechanism controlling MCL-1 stability that has been usurped by a viral oncogene to precipitate cell survival and transformation.

HTLV-1 Tax Stabilizes MCL-1 via TRAF6-Dependent K63-Linked Polyubiquitination to Promote Cell Survival and Transformation

Science.gov (United States)

Choi, Young Bong; Harhaj, Edward William

2014-01-01

The human T-cell leukemia virus type 1 (HTLV-1) Tax protein hijacks the host ubiquitin machinery to activate IκB kinases (IKKs) and NF-κB and promote cell survival; however, the key ubiquitinated factors downstream of Tax involved in cell transformation are unknown. Using mass spectrometry, we undertook an unbiased proteome-wide quantitative survey of cellular proteins modified by ubiquitin in the presence of Tax or a Tax mutant impaired in IKK activation. Tax induced the ubiquitination of 22 cellular proteins, including the anti-apoptotic BCL-2 family member MCL-1, in an IKK-dependent manner. Tax was found to promote the nondegradative lysine 63 (K63)-linked polyubiquitination of MCL-1 that was dependent on the E3 ubiquitin ligase TRAF6 and the IKK complex. Tax interacted with and activated TRAF6, and triggered its mitochondrial localization, where it conjugated four carboxyl-terminal lysine residues of MCL-1 with K63-linked polyubiquitin chains, which stabilized and protected MCL-1 from genotoxic stress-induced degradation. TRAF6 and MCL-1 played essential roles in the survival of HTLV-1 transformed cells and the immortalization of primary T cells by HTLV-1. Therefore, K63-linked polyubiquitination represents a novel regulatory mechanism controlling MCL-1 stability that has been usurped by a viral oncogene to precipitate cell survival and transformation. PMID:25340740

Structural and metabolic studies of O-linked fucose-containing proteins of normal and virally-transformed rat fibroblasts

International Nuclear Information System (INIS)

Morton, P.A.

1985-01-01

Previous studies in this laboratory have demonstrated that cultured human and rodent cells contain a series of low molecular weight glycosylated amino acids of unusual structure, designated amino acid fucosides. The incorporation of radiolabelled-fucose into one of these components, designated FL4a (glucosylfucosylthreonine), is markedly-reduced in transformed epithelial and fibroblastic cells. The authors have examined fucose-labelled normal and virally-transformed rat fibroblast cell lines for glycoproteins which might be precursors to amino acid fucosides. Using milk alkaline/borohydride treatment (the beta-elimination reaction) to release O-linked oligosaccharides from proteins, they have isolated and partially characterized two low M/sub r/ reaction products (designated DS-ol and TS-ol) released from macromolecular cell material. The identity of one of these components (DS-ol, glucosylfucitol) suggested the existence in these cells of a direct protein precursor to FL4a. They examined fucose-labelled macromolecular cell material for proteins which release DS-ol (DS-proteins.). Using gel filtration chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) with subsequent autoradiography, they have observed DS-proteins which appear to exhibit a broad molecular weight size range, and are also present in culture medium from normal and transformed cells. The findings suggest that mammalian cells contain DS-proteins and TS-proteins with a novel carbohydrate-peptide linkage wherein L-fucose is O-linked to a polypeptide backbone. Metabolic studies were undertaken to examine both the relationship between DS-protein and FL4a and the biochemical basis for the decreased level of FL4a and the biochemical basis for the decreased level of FL4a observed in transformed cells

On the determination of the dynamic properties of a transformer oil based ferrofluid in the frequency range 0.1-20 GHz

Science.gov (United States)

Fannin, P. C.; Vekas, L.; Marin, C. N.; Malaescu, I.

2017-02-01

Complex susceptibility measurements provide a unique and efficient means for the investigation and determination of the dynamic properties of magnetic fluids. In particular, measurement of the frequency, f(Hz), and field, H(kA/m), dependent, complex susceptibility, χ(ω, Η)= χ‧(ω, Η)-iχ″(ω, Η), of magnetic fluids has proven to be a valuable and reliable technique for investigating such properties. The experimental data presented here was obtained from measurements of a transformer oil based ferrofluid, with measurements being performed over the frequency range 0.1-20 GHz and polarising fields 0-168 kA/m. In the case of transformer oil magnetic fluids, the normal measurement emphasis has been on the investigation of their dielectric properties, including the effects which lightning may have on these properties. Little has been reported on the measurement of the corresponding magnetic susceptibility, χ(ω), of such fluids and in this paper we address this fact. Thus we consider it worthwhile, in the case of a transformer with magnetic fluid transformer oil, being affected as a result of a lightening occurrence, to have knowledge of the fluids dynamic properties, at the microwave frequencies. In the process of determining the sample susceptibility profiles, it was found that the peak value of the χ″(ω) component, was approximately constant over the frequency range 2.4-6.3 GHz. From this it was determined that the fluid was effectively operating as a wideband absorber over a bandwidth of 3.9 GHz.

Performance of the Wavelet Transform-Neural Network Based Receiver for DPIM in Diffuse Indoor Optical Wireless Links in Presence of Artificial Light Interference

Directory of Open Access Journals (Sweden)

Sujan Rajbhandari

2009-06-01

Full Text Available Artificial neural network (ANN has application in communication engineering in diverse areas such as channel equalization, channel modeling, error control code because of its capability of nonlinear processing, adaptability, and parallel processing. On the other hand, wavelet transform (WT with both the time and the frequency resolution provides the exact representation of signal in both domains. Applying these signal processing tools for channel compensation and noise reduction can provide an enhanced performance compared to the traditional tools. In this paper, the slot error rate (SER performance of digital pulse interval modulation (DPIM in diffuse indoor optical wireless (OW links subjected to the artificial light interference (ALI is reported with new receiver structure based on the discrete WT (DWT and ANN. Simulation results show that the DWT-ANN based receiver is very effective in reducing the effect of multipath induced inter-symbol interference (ISI and ALI.

Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

Science.gov (United States)

Pitel, I.J.

1987-02-03

The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage. 19 figs.

Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

Science.gov (United States)

Pitel, Ira J.

1987-02-03

The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage.

Linking transformational leadership and organizational culture

NARCIS (Netherlands)

den Hartog, D.N.; van Meijen, J.J.; Koopman, P.L.

1996-01-01

Many authors assume a strong relationship between culture and leadership in organizations. Leaders create, transform and manage organizational cultures. Although this linkage between organizational culture and leadership is often referred to, hypotheses and propositions are often not specific and

Algorithm, applications and evaluation for protein comparison by Ramanujan Fourier transform.

Science.gov (United States)

Zhao, Jian; Wang, Jiasong; Hua, Wei; Ouyang, Pingkai

2015-12-01

The amino acid sequence of a protein determines its chemical properties, chain conformation and biological functions. Protein sequence comparison is of great importance to identify similarities of protein structures and infer their functions. Many properties of a protein correspond to the low-frequency signals within the sequence. Low frequency modes in protein sequences are linked to the secondary structures, membrane protein types, and sub-cellular localizations of the proteins. In this paper, we present Ramanujan Fourier transform (RFT) with a fast algorithm to analyze the low-frequency signals of protein sequences. The RFT method is applied to similarity analysis of protein sequences with the Resonant Recognition Model (RRM). The results show that the proposed fast RFT method on protein comparison is more efficient than commonly used discrete Fourier transform (DFT). RFT can detect common frequencies as significant feature for specific protein families, and the RFT spectrum heat-map of protein sequences demonstrates the information conservation in the sequence comparison. The proposed method offers a new tool for pattern recognition, feature extraction and structural analysis on protein sequences. Copyright © 2015 Elsevier Ltd. All rights reserved.

Long-Distance Frequency Transfer Over an Urban Fiber Link Using Optical Phase Stabilization

Science.gov (United States)

2008-12-01

compensated link based n the principle first described in [19]. The ultrastable la - ig. 1. Phase noise power spectral density versus Fourier fre- uency of...de la Recherche (ANR BLAN06-3144016). SYRTE is Unité Mixte de Recherche of CNRS, Observatoire de aris, and Université Pierre et Marie Curie...Comparison between frequency standards in Europe and the USA at the 10−15 uncertainty level,” Metrologia 43, 109–120 (2006). 2. C. Vian, P. Rosenbusch, H

Transformer modeling for low- and mid-frequency electromagnetic transients simulation

Science.gov (United States)

Lambert, Mathieu

In this work, new models are developed for single-phase and three-phase shell-type transformers for the simulation of low-frequency transients, with the use of the coupled leakage model. This approach has the advantage that it avoids the use of fictitious windings to connect the leakage model to a topological core model, while giving the same response in short-circuit as the indefinite admittance matrix (BCTRAN) model. To further increase the model sophistication, it is proposed to divide windings into coils in the new models. However, short-circuit measurements between coils are never available. Therefore, a novel analytical method is elaborated for this purpose, which allows the calculation in 2-D of short-circuit inductances between coils of rectangular cross-section. The results of this new method are in agreement with the results obtained from the finite element method in 2-D. Furthermore, the assumption that the leakage field is approximately 2-D in shell-type transformers is validated with a 3-D simulation. The outcome of this method is used to calculate the self and mutual inductances between the coils of the coupled leakage model and the results are showing good correspondence with terminal short-circuit measurements. Typically, leakage inductances in transformers are calculated from short-circuit measurements and the magnetizing branch is calculated from no-load measurements, assuming that leakages are unimportant for the unloaded transformer and that magnetizing current is negligible during a short-circuit. While the core is assumed to have an infinite permeability to calculate short-circuit inductances, and it is a reasonable assumption since the core's magnetomotive force is negligible during a short-circuit, the same reasoning does not necessarily hold true for leakage fluxes in no-load conditions. This is because the core starts to saturate when the transformer is unloaded. To take this into account, a new analytical method is developed in this

Optimal Operation of Distribution Electronic Power Transformer Using Linear Quadratic Regulator Method

Directory of Open Access Journals (Sweden)

Mohammad Hosein Rezaei

2011-10-01

Full Text Available Transformers perform many functions such as voltage transformation, isolation and noise decoupling. They are indispensable components in electric power distribution system. However, at low frequencies (50 Hz, they are one of the heaviest and the most expensive equipment in an electrical distribution system. Nowadays, electronic power transformers are used instead of conventional power transformers that do voltage transformation and power delivery in power system by power electronic converter. In this paper, the structure of distribution electronic power transformer (DEPT are analized and then paid attention on the design of a linear-quadratic-regulator (LQR with integral action to improve dynamic performance of DEPT with voltage unbalance, voltage sags, voltage harmonics and voltage flicker. The presentation control strategy is simulated by MATLAB/SIMULINK. In addition, the results that are in terms of dc-link reference voltage, input and output voltages clearly show that a better dynamic performance can be achieved by using the LQR method when compared to other techniques.

Enhancement of stereoscopic comfort by fast control of frequency content with wavelet transform

Science.gov (United States)

Lemmer, Nicolas; Moreau, Guillaume; Fuchs, Philippe

2003-05-01

As the scope of virtual reality applications including stereoscopic imaging becomes wider, it is quite clear that not every designer of a VR application thinks of its constraints in order to make a correct use of stereo. Stereoscopic imagery though not required can be a useful tool for depth perception. It is possible to limit the depth of field as shown by Perrin who has also undertaken research on the link between the ability of fusing stereoscopic images (stereopsis) and local disparity and spatial frequency content. We will show how we can extend and enhance this work especially on the computational complexity point of view. The wavelet theory allows us to define a local spatial frequency and then a local measure of stereoscopic comfort. This measure is based on local spatial frequency and disparity as well as on the observations made by Woepking. Local comfort estimation allows us to propose several filtering methods to enhance this comfort. The idea to modify the images such as they check a "stereoscopic comfort condition" defined as a threshold for the stereoscopic comfort condition. More technically, we seek to limit high spatial frequency content when disparity is high thanks to the use of fast algorithms.

Iterative normalization technique for reference sequence generation for zero-tail discrete fourier transform spread orthogonal frequency division multiplexing

DEFF Research Database (Denmark)

2017-01-01

Systems, methods, apparatuses, and computer program products for generating sequences for zero-tail discrete fourier transform (DFT)-spread-orthogonal frequency division multiplexing (OFDM) (ZT DFT-s-OFDM) reference signals. One method includes adding a zero vector to an input sequence...... of each of the elements, converting the sequence to time domain, generating a zero-padded sequence by forcing a zero head and tail of the sequence, and repeating the steps until a final sequence with zero-tail and flat frequency response is obtained....

More Use Almost Always Means a Smaller Frequency Effect: Aging, Bilingualism, and the Weaker Links Hypothesis

Science.gov (United States)

Gollan, Tamar H.; Montoya, Rosa I.; Cera, Cynthia; Sandoval, Tiffany C.

2008-01-01

The "weaker links" hypothesis proposes that bilinguals are disadvantaged relative to monolinguals on speaking tasks because they divide frequency-of-use between two languages. To test this proposal, we contrasted the effects of increased word use associated with monolingualism, language dominance, and increased age on picture naming times. In two…

Integrated InP frequency discriminator for Phase-modulated microwave photonic links.

Science.gov (United States)

Fandiño, J S; Doménech, J D; Muñoz, P; Capmany, J

2013-02-11

We report the design, fabrication and characterization of an integrated frequency discriminator on InP technology for microwave photonic phase modulated links. The optical chip is, to the best of our knowledge, the first reported in an active platform and the first to include the optical detectors. The discriminator, designed as a linear filter in intensity, features preliminary SFDR values the range between 67 and 79 dB.Hz(2/3) for signal frequencies in the range of 5-9 GHz limited, in principle, by the high value of the optical losses arising from the use of several free space coupling devices in our experimental setup. As discussed, these losses can be readily reduced by the use of integrated spot-size converters improving the SFDR by 17.3 dB (84-96 dB.Hz(2/3)). Further increase up to a range of (104-116 dB.Hz(2/3)) is possible by reducing the system noise eliminating the EDFA employed in the setup and using a commercially available laser source providing higher output power and lower relative intensity noise. Other paths for improvement requiring a filter redesign to be linear in the optical field are also discussed.

Perceptual Coding of Audio Signals Using Adaptive Time-Frequency Transform

Directory of Open Access Journals (Sweden)

Umapathy Karthikeyan

2007-01-01

Full Text Available Wide band digital audio signals have a very high data-rate associated with them due to their complex nature and demand for high-quality reproduction. Although recent technological advancements have significantly reduced the cost of bandwidth and miniaturized storage facilities, the rapid increase in the volume of digital audio content constantly compels the need for better compression algorithms. Over the years various perceptually lossless compression techniques have been introduced, and transform-based compression techniques have made a significant impact in recent years. In this paper, we propose one such transform-based compression technique, where the joint time-frequency (TF properties of the nonstationary nature of the audio signals were exploited in creating a compact energy representation of the signal in fewer coefficients. The decomposition coefficients were processed and perceptually filtered to retain only the relevant coefficients. Perceptual filtering (psychoacoustics was applied in a novel way by analyzing and performing TF specific psychoacoustics experiments. An added advantage of the proposed technique is that, due to its signal adaptive nature, it does not need predetermined segmentation of audio signals for processing. Eight stereo audio signal samples of different varieties were used in the study. Subjective (mean opinion score—MOS listening tests were performed and the subjective difference grades (SDG were used to compare the performance of the proposed coder with MP3, AAC, and HE-AAC encoders. Compression ratios in the range of 8 to 40 were achieved by the proposed technique with subjective difference grades (SDG ranging from –0.53 to –2.27.

AEP's selection of GE Energy's variable frequency transformer (VFT) for their grid interconnection project between the United States and Mexico

Energy Technology Data Exchange (ETDEWEB)

Spurlock, M.; O' Keefe, R. [American Electric Power, Gahanna, OH (United States); Kidd, D. [American Electric Power, Tulsa, OK (United States); Larsen, E. [GE Energy, Schenectady, NY (United States); Roedel, J. [GE Energy, Denver, CO (United States); Bodo, R. [GE Energy, Carrolton, TX (United States); Marken, P. [GE Energy, Columbia City, IN (United States)

2006-07-01

Variable frequency transformers (VFTs) are controllable, bi-directional transmission devices capable of allowing power transfer between asynchronous networks. The VFT uses a rotary transformer with 3-phase windings on both the rotor and the stator. A motor and drive system is also used to manipulate the rotational position of the rotor in order to control the magnitude and direction of the power flow. The VFT was recently selected by American Electric Power (AEP) for its new asynchronous transmission link between the United States and Mexico. This paper provided details of the feasibility studies conducted to select the technology. Three categories of asynchronous interconnection devices were evaluated: (1) a VFT; (2) a voltage source converter; and (3) a conventional high voltage direct current (HVDC) back-to-back system. Stability performance system studies were conducted for all options. The overall reliability benefits of the options were reviewed, as well as their ability to meet steady-state system requirements. Dynamic models were used to conduct the comparative evaluation. Results of the feasibility study indicated that both the VFT and the voltage source converter performed better than the HVDC system. However, the VFT was more stable than the voltage source converter. 5 refs., 3 figs.

Implementation guidance for industrial-level security systems using radio frequency alarm links

Energy Technology Data Exchange (ETDEWEB)

Swank, R.G.

1996-07-12

Spread spectrum (SS) RF transmission technologies have properties that make the transmitted signal difficult to intercept, interpret, and jam. The digital code used in the modulation process results in a signal that has high reception reliability and supports multiple use of frequency bands and selective addressing. These attributes and the relatively low installation cost of RF systems make SSRF technologies candidate for communications links in security systems used for industrial sites, remote locations, and where trenching or other disturbances of soil or structures may not be desirable or may be costly. This guide provides a description of such a system and presents implementation methods that may be of engineering benefit.

A new fractional wavelet transform

Science.gov (United States)

Dai, Hongzhe; Zheng, Zhibao; Wang, Wei

2017-03-01

The fractional Fourier transform (FRFT) is a potent tool to analyze the time-varying signal. However, it fails in locating the fractional Fourier domain (FRFD)-frequency contents which is required in some applications. A novel fractional wavelet transform (FRWT) is proposed to solve this problem. It displays the time and FRFD-frequency information jointly in the time-FRFD-frequency plane. The definition, basic properties, inverse transform and reproducing kernel of the proposed FRWT are considered. It has been shown that an FRWT with proper order corresponds to the classical wavelet transform (WT). The multiresolution analysis (MRA) associated with the developed FRWT, together with the construction of the orthogonal fractional wavelets are also presented. Three applications are discussed: the analysis of signal with time-varying frequency content, the FRFD spectrum estimation of signals that involving noise, and the construction of fractional Harr wavelet. Simulations verify the validity of the proposed FRWT.

Perceptual Coding of Audio Signals Using Adaptive Time-Frequency Transform

Directory of Open Access Journals (Sweden)

Karthikeyan Umapathy

2007-08-01

Full Text Available Wide band digital audio signals have a very high data-rate associated with them due to their complex nature and demand for high-quality reproduction. Although recent technological advancements have significantly reduced the cost of bandwidth and miniaturized storage facilities, the rapid increase in the volume of digital audio content constantly compels the need for better compression algorithms. Over the years various perceptually lossless compression techniques have been introduced, and transform-based compression techniques have made a significant impact in recent years. In this paper, we propose one such transform-based compression technique, where the joint time-frequency (TF properties of the nonstationary nature of the audio signals were exploited in creating a compact energy representation of the signal in fewer coefficients. The decomposition coefficients were processed and perceptually filtered to retain only the relevant coefficients. Perceptual filtering (psychoacoustics was applied in a novel way by analyzing and performing TF specific psychoacoustics experiments. An added advantage of the proposed technique is that, due to its signal adaptive nature, it does not need predetermined segmentation of audio signals for processing. Eight stereo audio signal samples of different varieties were used in the study. Subjective (mean opinion score—MOS listening tests were performed and the subjective difference grades (SDG were used to compare the performance of the proposed coder with MP3, AAC, and HE-AAC encoders. Compression ratios in the range of 8 to 40 were achieved by the proposed technique with subjective difference grades (SDG ranging from –0.53 to –2.27.

A study of the impact of frequency selectivity on link adaptive wireless LAN systems

OpenAIRE

Armour, SMD; Doufexi, A; Nix, AR; Bull, DR

2002-01-01

Wireless local area networks (WLANs) supporting broadband multimedia communication are being developed and standardized around the world. The HIPERLAN/2, 802.11a and HiSWANa standards provide channel adaptive data rates between 6 and 54 Mbps in the 5GHz radio band. The link adaptation mechanism is not specified in the standards. In this paper the performance of the HIPERLAN/2 system is evaluated in terms of throughput in a range of test channels with different degrees of frequency selectivity...

High-frequency transformation of a methylotrophic yeast, Candida boidinii, with autonomously replicating plasmids which are also functional in Saccharomyces cerevisiae.

OpenAIRE

Sakai, Y; Goh, T K; Tani, Y

1993-01-01

We have developed a transformation system which uses autonomous replicating plasmids for a methylotrophic yeast, Candida boidinii. Two autonomous replication sequences, CARS1 and CARS2, were newly cloned from the genome of C. boidinii. Plasmids having both a CARS fragment and the C. boidinii URA3 gene transformed C. boidinii ura3 cells to Ura+ phenotype at frequencies of up to 10(4) CFU/micrograms of DNA. From Southern blot analysis, CARS plasmids seemed to exist in polymeric forms as well as...

Cell density dependence of transformation frequencies in C3H10T1/2 cells exposed to X-rays

Energy Technology Data Exchange (ETDEWEB)

Bettega, D; Calzolari, P; Ottolenghi, A; Lombardi, L T [Milan Univ. (Italy). Ist. di Fisica; Rimoldi, E [Milan Univ. (Italy). Ist. di Radiologia Veterinaria

1989-12-01

The effects of cell density on transformation frequencies were studied in C3H10T1/2 cells exposed to 0.5 and 7 Gy of 200 kVp X-rays. Initial cell density strongly influenced transformation frequency; this decreased by a factor of between 4 and 10 when the initial seeding density was changed from 50 to 2500 cells/10 cm diameter Petri dish. The data were fitted with two equations: (a) an allometric function represented on a log-log scale by a straight line and (b) a sigmoidal function with plateaux between 50 and 250 cells/dish and above 600. The two curves are compared and their probabilities discussed. Our data indicate that the region between 50 and 250 cells/dish would be the most suitable region for dose-effect measurements. A study of the growth curves at 0.5 and 8.5 Gy shows that cell growth rates are not influenced by initial cell density. (author).

Impact of frequency modulation ratio on capacitor cells balancing in phase-shifted PWM based chain-link STATCOM

DEFF Research Database (Denmark)

Behrouzian, Ehsan; Bongiorno, Massimo; Teodorescu, Remus

2014-01-01

to provide more uniform power distribution among the cells, two different methods called, a) carrier swapping and b) non-integer frequency modulation ratio are studied. In particular, it is shown that the selection of a non-integer frequency modulation ratio helps in providing a more uniform power......The purpose of this paper is to investigate the impact of switching harmonics on the instantaneous power that flows in the cells of a chain-link based STATCOM when using Phase-Shifted PWM. Two different cases are investigated for the converter cells: low, and high switching frequency. It is shown...... that any deviation from the ideal conditions lead to undesired harmonics, which will impact the charge of the dc capacitors. It is also shown that for low switching frequencies, cells voltage sideband harmonics interact with baseband harmonics of the current and causes extra source of unbalance. In order...

Disc piezoelectric ceramic transformers.

Science.gov (United States)

Erhart, Jirií; Půlpán, Petr; Doleček, Roman; Psota, Pavel; Lédl, Vít

2013-08-01

In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 Ω to 10 kΩ, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power.

Global gene expression profiling of brown to white adipose tissue transformation in sheep reveals novel transcriptional components linked to adipose remodeling

DEFF Research Database (Denmark)

Basse, Astrid L.; Dixen, Karen; Yadav, Rachita

2015-01-01

. Conclusions: Using global gene expression profiling of the postnatal BAT to WAT transformation in sheep, we provide novel insight into adipose tissue plasticity in a large mammal, including identification of novel transcriptional components linked to adipose tissue remodeling. Moreover, our data set provides...... NR1H3, MYC, KLF4, ESR1, RELA and BCL6, which were linked to the overall changes in gene expression during the adipose tissue remodeling. Finally, the perirenal adipose tissue expressed both brown and brite/beige adipocyte marker genes at birth, the expression of which changed substantially over time...

Calculation of Leakage Inductance for High Frequency Transformers

DEFF Research Database (Denmark)

Ouyang, Ziwei; Jun, Zhang; Hurley, William Gerard

2015-01-01

Frequency dependent leakage inductance is often observed. High frequency eddy current effects cause a reduction in leakage inductance. The proximity effect between adjacent layers is responsible for the reduction of leakage inductance. This paper gives a detailed analysis of high frequency leakag...

A new time-frequency method to reveal quantum dynamics of atomic hydrogen in intense laser pulses: Synchrosqueezing transform

International Nuclear Information System (INIS)

Sheu, Yae-lin; Hsu, Liang-Yan; Wu, Hau-tieng; Li, Peng-Cheng; Chu, Shih-I

2014-01-01

This study introduces a new adaptive time-frequency (TF) analysis technique, the synchrosqueezing transform (SST), to explore the dynamics of a laser-driven hydrogen atom at an ab initio level, upon which we have demonstrated its versatility as a new viable venue for further exploring quantum dynamics. For a signal composed of oscillatory components which can be characterized by instantaneous frequency, the SST enables rendering the decomposed signal based on the phase information inherited in the linear TF representation with mathematical support. Compared with the classical type of TF methods, the SST clearly depicts several intrinsic quantum dynamical processes such as selection rules, AC Stark effects, and high harmonic generation

Thin-Film Power Transformers

Science.gov (United States)

Katti, Romney R.

1995-01-01

Transformer core made of thin layers of insulating material interspersed with thin layers of ferromagnetic material. Flux-linking conductors made of thinner nonferromagnetic-conductor/insulator multilayers wrapped around core. Transformers have geometric features finer than those of transformers made in customary way by machining and mechanical pressing. In addition, some thin-film materials exhibit magnetic-flux-carrying capabilities superior to those of customary bulk transformer materials. Suitable for low-cost, high-yield mass production.

Extremely low-frequency magnetic fields of transformers and possible biological and health effects.

Science.gov (United States)

Sirav, Bahriye; Sezgin, Gaye; Seyhan, Nesrin

2014-12-01

Physiological processes in organisms can be influenced by extremely low-frequency (ELF) electromagnetic energy. Biological effect studies have great importance; as well as measurement studies since they provide information on the real exposure situations. In this study, the leakage magnetic fields around a transformer were measured in an apartment building in Küçükçekmece, Istanbul, and the measurement results were evaluated with respect to the international exposure standards. The transformer station was on the bottom floor of a three-floor building. It was found that people living and working in the building were exposed to ELF magnetic fields higher than the threshold magnetic field value of the International Agency for Research on Cancer (IARC). Many people living in this building reported health complaints such as immunological problems of their children. There were child-workers working in the textile factories located in the building. Safe distances or areas for these people should be recommended. Protective measures could be implemented to minimize these exposures. Further residential exposure studies are needed to demonstrate the exposure levels of ELF magnetic fields. Precautions should, therefore, be taken either to reduce leakage or minimize the exposed fields. Shielding techniques should be used to minimize the leakage magnetic fields in such cases.

Embedded Solenoid Transformer for Power Conversion

DEFF Research Database (Denmark)

2015-01-01

A resonant power converter for operation in the radio frequency range, preferably in the VHF, comprises at least one PCB-embedded transformer. The transformer is configured for radio frequency operation and comprises a printed circuit board defining a horizontal plane, the printed circuit board...... comprising at least two horizontal conductive layers separated by an isolating layer, a first embedded solenoid forming a primary winding of the transformer and a second embedded solenoid being arranged parallel to the first solenoid and forming a secondary winding of the transformer, wherein the first...

Discrimination Between Inrush and Short Circuit Currents in Differential Protection of Power Transformer Based on Correlation Method Using the Wavelet Transform

OpenAIRE

M. Rasoulpoor; M. Banejad; A. Ahmadyfard

2011-01-01

This paper presents a novel technique for transformer differential protection to prevent incorrect operation due to inrush current. The proposed method in this paper is based on time-frequency transform known as the Wavelet transform. The discrete Wavelet transform is used for analysis the differential current signals in time and frequency domains. The investigation on the energy distribution of the signal on the discrete Wavelet transform components shows the difference distribution between ...

Non-stationary signal analysis based on general parameterized time-frequency transform and its application in the feature extraction of a rotary machine

Science.gov (United States)

Zhou, Peng; Peng, Zhike; Chen, Shiqian; Yang, Yang; Zhang, Wenming

2018-06-01

With the development of large rotary machines for faster and more integrated performance, the condition monitoring and fault diagnosis for them are becoming more challenging. Since the time-frequency (TF) pattern of the vibration signal from the rotary machine often contains condition information and fault feature, the methods based on TF analysis have been widely-used to solve these two problems in the industrial community. This article introduces an effective non-stationary signal analysis method based on the general parameterized time-frequency transform (GPTFT). The GPTFT is achieved by inserting a rotation operator and a shift operator in the short-time Fourier transform. This method can produce a high-concentrated TF pattern with a general kernel. A multi-component instantaneous frequency (IF) extraction method is proposed based on it. The estimation for the IF of every component is accomplished by defining a spectrum concentration index (SCI). Moreover, such an IF estimation process is iteratively operated until all the components are extracted. The tests on three simulation examples and a real vibration signal demonstrate the effectiveness and superiority of our method.

Joint Time-Frequency And Wavelet Analysis - An Introduction

Directory of Open Access Journals (Sweden)

Majkowski Andrzej

2014-12-01

Full Text Available A traditional frequency analysis is not appropriate for observation of properties of non-stationary signals. This stems from the fact that the time resolution is not defined in the Fourier spectrum. Thus, there is a need for methods implementing joint time-frequency analysis (t/f algorithms. Practical aspects of some representative methods of time-frequency analysis, including Short Time Fourier Transform, Gabor Transform, Wigner-Ville Transform and Cone-Shaped Transform are described in this paper. Unfortunately, there is no correlation between the width of the time-frequency window and its frequency content in the t/f analysis. This property is not valid in the case of a wavelet transform. A wavelet is a wave-like oscillation, which forms its own “wavelet window”. Compression of the wavelet narrows the window, and vice versa. Individual wavelet functions are well localized in time and simultaneously in scale (the equivalent of frequency. The wavelet analysis owes its effectiveness to the pyramid algorithm described by Mallat, which enables fast decomposition of a signal into wavelet components.

Transformers: analysis, design, and measurement

National Research Council Canada - National Science Library

López-Fernández, Xose M; Ertan, H. Bülent; Turowski, J

2013-01-01

"This book focuses on contemporary economic, design, diagnostics, and maintenance aspects of power, instrument, and high frequency transformers, which are critical to designers for a transformer stations...

A novel joint timing/frequency synchronization scheme based on Radon-Wigner transform of LFM signals in CO-OFDM systems

Science.gov (United States)

Liu, Jianfei; Wei, Ying; Zeng, Xiangye; Lu, Jia; Zhang, Shuangxi; Wang, Mengjun

2018-03-01

A joint timing and frequency synchronization method has been proposed for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) system in this paper. The timing offset (TO), integer frequency offset (FO) and the fractional FO can be realized by only one training symbol, which consists of two linear frequency modulation (LFM) signals with opposite chirp rates. By detecting the peak of LFM signals after Radon-Wigner transform (RWT), the TO and the integer FO can be estimated at the same time, moreover, the fractional FO can be acquired correspondingly through the self-correlation characteristic of the same training symbol. Simulation results show that the proposed method can give a more accurate TO estimation than the existing methods, especially at poor OSNR conditions; for the FO estimation, both the fractional and the integer FO can be estimated through the proposed training symbol with no extra overhead, a more accurate estimation and a large FO estimation range of [ - 5 GHz, 5GHz] can be acquired.

Multi-Functional Fibre-Optic Microwave Links

DEFF Research Database (Denmark)

Gliese, Ulrik Bo

1998-01-01

The multi-functionality of microwave links based on remote heterodyne detection of signals from a dual-frequency laser transmitter is discussed and experimentally demonstrated in this paper. Typically, direct detection in conjunction with optical intensity modulation is used to implement fibre......-optic microwave links. The resulting links are inherently transparent and mainly used for signal transmission. As opposed to direct detection links, remote heterodyne detection links can directly perform functionalities such as modulation, frequency conversion, and transparent signal recovery in addition...

Low- and high-frequency Raman investigations on caffeine: polymorphism, disorder and phase transformation.

Science.gov (United States)

Hédoux, Alain; Decroix, Anne-Amandine; Guinet, Yannick; Paccou, Laurent; Derollez, Patrick; Descamps, Marc

2011-05-19

Raman investigations are carried out both in crystalline forms of caffeine and during the isothermal transformation of the orientationally disordered form I into the stable form II at 363 K. The time dependence of the Raman spectrum exhibits no significant change in the intramolecular regime (above 100 cm(-1)), resembling the spectrum of the liquid state. By contrast, significant changes are observed below 100 cm(-1), and the low-frequency spectra of forms I and II are observed to be different from that of the liquid. The temperature dependence of the 5-600 cm(-1) spectrum gives information on the static disorder through the analysis of collective motions, while information on dynamic disorder are obtained from the study of the 555 cm(-1) band corresponding to internal vibrations in the pyrimidine ring. This analysis indubitably reveals that form II is also orientationally disordered with a local molecular arrangement that mimics that in form I and the liquid state. The comparison of the low-frequency spectra recorded in theophylline and form II of caffeine allows one to describe the stable form of caffeine from the packing arrangement of anhydrous theophylline with the consideration of reorientational molecular disorder. © 2011 American Chemical Society

High Accuracy Evaluation of the Finite Fourier Transform Using Sampled Data

Science.gov (United States)

Morelli, Eugene A.

1997-01-01

Many system identification and signal processing procedures can be done advantageously in the frequency domain. A required preliminary step for this approach is the transformation of sampled time domain data into the frequency domain. The analytical tool used for this transformation is the finite Fourier transform. Inaccuracy in the transformation can degrade system identification and signal processing results. This work presents a method for evaluating the finite Fourier transform using cubic interpolation of sampled time domain data for high accuracy, and the chirp Zeta-transform for arbitrary frequency resolution. The accuracy of the technique is demonstrated in example cases where the transformation can be evaluated analytically. Arbitrary frequency resolution is shown to be important for capturing details of the data in the frequency domain. The technique is demonstrated using flight test data from a longitudinal maneuver of the F-18 High Alpha Research Vehicle.

submitter Development of a 100 kW, 12.5 kV, 22 kHz and 30 kV insulated medium frequency transformer for compact and reliable medium voltage power conversion

CERN Document Server

Isler, Stephane; Aguglia, Davide; Bonnin, Xavier Abel

2017-01-01

This paper presents the critical design aspects addressed during the development of a 100 kW, 12.5 kV, 22 kHz, and 30 kV insulated medium frequency transformer used in a power converter. The transformers are used in a resonant multilevel converter topology producing HV DC voltage from a three phase 400 V AC industrial grid. The power converter is used to supply radio frequency systems in particle accelerators. Considerations about material selection, dielectric, magnetic and thermal design are discussed and experimental results on the full scale transformer and power converter are presented.

Transformers analysis, design, and measurement

CERN Document Server

Lopez-Fernandez, Xose M; Turowski, Janusz

2012-01-01

This book focuses on contemporary economic, design, diagnostics, and maintenance aspects of power, instrument, and high frequency transformers, which are critical to designers for a transformer stations. The text covers such topics as shell type and superconducting transformers as well as coreless PCB and planar transformers. It emphasizes challenges and strategies in transformer design and illustrates the importance of economics in transformers management by reviewing life cycle cost design and the use of decision methods to manage risk.

Fractional finite Fourier transform.

Science.gov (United States)

Khare, Kedar; George, Nicholas

2004-07-01

We show that a fractional version of the finite Fourier transform may be defined by using prolate spheroidal wave functions of order zero. The transform is linear and additive in its index and asymptotically goes over to Namias's definition of the fractional Fourier transform. As a special case of this definition, it is shown that the finite Fourier transform may be inverted by using information over a finite range of frequencies in Fourier space, the inversion being sensitive to noise. Numerical illustrations for both forward (fractional) and inverse finite transforms are provided.

Generalized Modular Transformations in (3+1D Topologically Ordered Phases and Triple Linking Invariant of Loop Braiding

Directory of Open Access Journals (Sweden)

Shenghan Jiang

2014-09-01

Full Text Available In topologically ordered quantum states of matter in (2+1D (spacetime dimensions, the braiding statistics of anyonic quasiparticle excitations is a fundamental characterizing property that is directly related to global transformations of the ground-state wave functions on a torus (the modular transformations. On the other hand, there are theoretical descriptions of various topologically ordered states in (3+1D, which exhibit both pointlike and looplike excitations, but systematic understanding of the fundamental physical distinctions between phases, and how these distinctions are connected to quantum statistics of excitations, is still lacking. One main result of this work is that the three-dimensional generalization of modular transformations, when applied to topologically ordered ground states, is directly related to a certain braiding process of looplike excitations. This specific braiding surprisingly involves three loops simultaneously, and can distinguish different topologically ordered states. Our second main result is the identification of the three-loop braiding as a process in which the worldsheets of the three loops have a nontrivial triple linking number, which is a topological invariant characterizing closed two-dimensional surfaces in four dimensions. In this work, we consider realizations of topological order in (3+1D using cohomological gauge theory in which the loops have Abelian statistics and explicitly demonstrate our results on examples with Z_{2}×Z_{2} topological order.

Linking Resilience and Transformation as Micro- and Macro Adaptation

Science.gov (United States)

Friedman, E.; Breitzer, R.; Solecki, W. D.

2017-12-01

The concept of resiliency within climate adaptation planning and practice is widespread, but in some ways it has begun to suffer from its own success. While resiliency provides a valuable frame for understanding the conditions and opportunities for localized responses to increasing climate risks, the concept's ubiquitous use leads to it being applied to often conflicting policy agendas, which can mask or limit the capacity to connect efforts focused on near term risk to longer term and emergent climate threats in communities. These challenges are particularly evident in the context of extreme events and in the post extreme event policy windows. To overcome these issues and take advantage of the post-event policy window, the NOAA RISA Climate Change Risk in the Urban Northeast (CCRUN) project has been developing two specific, "boutique", policy tools. These include the PELT (Post-event learning toolkit) and MART (Macro-adaptation Resilience toolkit) toolkits. Embedded in these toolkits are two approaches to small scale strategies often associated with near term action (i.e., micro-adaptation) and large scale strategies associated with broad longer term needs (i.e., macro-adaptation). In this paper, these two approaches - micro and macro adaptation - are theoretically defined and presented in practice through the beta-testing of the PELT and MART toolkits. Most importantly, we illustrate how the theoretical links between resiliency and transformation can be operationalized through the use of these approaches, and how these approaches can be implemented in everyday risk management practice. We present our work through selected case studies in the Northeast US region, specifically in Jamaica Bay, New York, and Eastwick neighborhood in Philadelphia.

a Signal-Tuned Gabor Transform with Application to Eeg Analysis

Science.gov (United States)

Torreão, José R. A.; Victer, Silvia M. C.; Fernandes, João L.

2013-04-01

We introduce a time-frequency transform based on Gabor functions whose parameters are given by the Fourier transform of the analyzed signal. At any given frequency, the width and the phase of the Gabor function are obtained, respectively, from the magnitude and the phase of the signal's corresponding Fourier component, yielding an analyzing kernel which is a representation of the signal's content at that particular frequency. The resulting Gabor transform tunes itself to the input signal, allowing the accurate detection of time and frequency events, even in situations where the traditional Gabor and S-transform approaches tend to fail. This is the case, for instance, when considering the time-frequency representation of electroencephalogram traces (EEG) of epileptic subjects, as illustrated by the experimental study presented here.

Pilot study of extremely low frequency magnetic fields emitted by transformers in dwellings. Social aspects.

Science.gov (United States)

Zaryabova, Victoria; Shalamanova, Tsvetelina; Israel, Michel

2013-06-01

A large number of epidemiologic studies examining the potential effect of residential exposure to extremely-low frequency (ELF) magnetic fields and childhood leukemia have been published. Two pooled analyses [Ahlbom A, Day N, Feychting M, Roman E, Skinner J, Dockerty J, Linet M, et al. (2000). A pooled analysis of magnetic fields and childhood leukaemia. Br J Cancer. 83(5):692-698; Greenland S, Sheppard AR, Kaune WT, Poole C, Kelsh AM (2000). A pooled analysis of magnetic fields, wire codes, and childhood leukemia. Epidemiology. 11(6):624-634], which included the major epidemiologic studies on ELF magnetic fields and childhood leukemia showed twofold increase in childhood leukemia risk in association with residential ELF exposure above 0.3-0.4 μT. Based on "limited" epidemiologic evidence linking ELF exposure to childhood leukemia and "inadequate evidence" for carcinogenicity of ELF in rodent bioassays, the International Agency for Research on Cancer (IARC) classified ELF magnetic fields as a possible human carcinogen (2B classification) [International Agency for Research on Cancer (IARC) (2002). Non-ionizing radiation, Part 1: Static and extremely low-frequency (ELF) electric and magnetic fields. IARC monographs on the evaluation of carcinogenic risks to humans. Vol. 80. IARC Press: Lyon], confirmed by WHO on the basis of studies published after 2000 [World Health Organization. Extremely low frequency fields. In: 238 Environmental health criteria, Geneva: WHO; 2007]. The analysis of more recent studies of ELF magnetic fields and childhood leukemia had small findings and propose methodological improvements concerning the uncertainties in epidemiological approaches and exposure assessment, bias in selection of controls [Kheifets L, Oksuzyan S (2008). Exposure assessment and other challenges in non-ionizing radiation studies of childhood leukaemia. Radiat Prot Dosimetry. 132(2):139-147]. By the end of 2010, 37 countries had been identified for possible participation

Coaxial pulse matching transformer

International Nuclear Information System (INIS)

Ledenev, V.V.; Khimenko, L.T.

1986-01-01

This paper describes a coaxial pulse matching transformer with comparatively simple design, increased mechanical strength, and low stray inductance. The transformer design makes it easy to change the turns ratio. The circuit of the device and an expression for the current multiplication factor are presented; experiments confirm the efficiency of the transformer. Apparatus with a coaxial transformer for producing high-power pulsed magnetic fields is designed (current pulses of 1-10 MA into a load and a natural frequency of 100 kHz)

Generalized field-transforming metamaterials

International Nuclear Information System (INIS)

Tretyakov, Sergei A; Nefedov, Igor S; Alitalo, Pekka

2008-01-01

In this paper, we introduce a generalized concept of field-transforming metamaterials, which perform field transformations defined as linear relations between the original and transformed fields. These artificial media change the fields in a prescribed fashion in the volume occupied by the medium. We show what electromagnetic properties of transforming medium are required. The coefficients of these linear functions can be arbitrary scalar functions of position and frequency, which makes the approach quite general and opens a possibility to realize various unusual devices.

Speech-evoked brainstem frequency-following responses during verbal transformations due to word repetition.

Science.gov (United States)

Galbraith, G C; Jhaveri, S P; Kuo, J

1997-01-01

Speech-evoked brainstem frequency-following responses (FFRs) were recorded to repeated presentations of the same stimulus word. Word repetition results in illusory verbal transformations (VTs) in which word perceptions can differ markedly from the actual stimulus. Previous behavioral studies support an explanation of VTs based on changes in arousal or attention. Horizontal and vertical dipole FFRs were recorded to assess responses with putative origins in the auditory nerve and central brainstem, respectively. FFRs were recorded from 18 subjects when they correctly heard the stimulus and when they reported VTs. Although horizontal and vertical dipole FFRs showed different frequency response patterns, dipoles did not differentiate between perceptual conditions. However, when subjects were divided into low- and high-VT groups (based on percentage of VT trials), a significant Condition x Group interaction resulted. This interaction showed the largest difference in FFR amplitudes during VT trials, with the low-VT group showing increased amplitudes, and the high-VT group showing decreased amplitudes, relative to trials in which the stimulus was correctly perceived. These results demonstrate measurable subject differences in the early processing of complex signals, due to possible effects of attention on the brainstem FFR. The present research shows that the FFR is useful in understanding human language as it is coded and processed in the brainstem auditory pathway.

Matching synchrosqueezing transform: A useful tool for characterizing signals with fast varying instantaneous frequency and application to machine fault diagnosis

Science.gov (United States)

Wang, Shibin; Chen, Xuefeng; Selesnick, Ivan W.; Guo, Yanjie; Tong, Chaowei; Zhang, Xingwu

2018-02-01

Synchrosqueezing transform (SST) can effectively improve the readability of the time-frequency (TF) representation (TFR) of nonstationary signals composed of multiple components with slow varying instantaneous frequency (IF). However, for signals composed of multiple components with fast varying IF, SST still suffers from TF blurs. In this paper, we introduce a time-frequency analysis (TFA) method called matching synchrosqueezing transform (MSST) that achieves a highly concentrated TF representation comparable to the standard TF reassignment methods (STFRM), even for signals with fast varying IF, and furthermore, MSST retains the reconstruction benefit of SST. MSST captures the philosophy of STFRM to simultaneously consider time and frequency variables, and incorporates three estimators (i.e., the IF estimator, the group delay estimator, and a chirp-rate estimator) into a comprehensive and accurate IF estimator. In this paper, we first introduce the motivation of MSST with three heuristic examples. Then we introduce a precise mathematical definition of a class of chirp-like intrinsic-mode-type functions that locally can be viewed as a sum of a reasonably small number of approximate chirp signals, and we prove that MSST does indeed succeed in estimating chirp-rate and IF of arbitrary functions in this class and succeed in decomposing these functions. Furthermore, we describe an efficient numerical algorithm for the practical implementation of the MSST, and we provide an adaptive IF extraction method for MSST reconstruction. Finally, we verify the effectiveness of the MSST in practical applications for machine fault diagnosis, including gearbox fault diagnosis for a wind turbine in variable speed conditions and rotor rub-impact fault diagnosis for a dual-rotor turbofan engine.

Predictability and interpretability of hybrid link-level crash frequency models for urban arterials compared to cluster-based and general negative binomial regression models.

Science.gov (United States)

Najaf, Pooya; Duddu, Venkata R; Pulugurtha, Srinivas S

2018-03-01

Machine learning (ML) techniques have higher prediction accuracy compared to conventional statistical methods for crash frequency modelling. However, their black-box nature limits the interpretability. The objective of this research is to combine both ML and statistical methods to develop hybrid link-level crash frequency models with high predictability and interpretability. For this purpose, M5' model trees method (M5') is introduced and applied to classify the crash data and then calibrate a model for each homogenous class. The data for 1134 and 345 randomly selected links on urban arterials in the city of Charlotte, North Carolina was used to develop and validate models, respectively. The outputs from the hybrid approach are compared with the outputs from cluster-based negative binomial regression (NBR) and general NBR models. Findings indicate that M5' has high predictability and is very reliable to interpret the role of different attributes on crash frequency compared to other developed models.

Fast Link Adaptation for MIMO-OFDM

DEFF Research Database (Denmark)

Jensen, Tobias Lindstrøm; Kant, Shashi; Wehinger, Joachim

2010-01-01

We investigate link-quality metrics (LQMs) based on raw bit-error-rate, effective signal-to-interference-plus-noise ratio, and mutual information (MI) for the purpose of fast link adaptation (LA) in communication systems employing orthogonal frequency-division multiplexing and multiple-input–mult......We investigate link-quality metrics (LQMs) based on raw bit-error-rate, effective signal-to-interference-plus-noise ratio, and mutual information (MI) for the purpose of fast link adaptation (LA) in communication systems employing orthogonal frequency-division multiplexing and multiple...

Applications of a fast, continuous wavelet transform

Energy Technology Data Exchange (ETDEWEB)

Dress, W.B.

1997-02-01

A fast, continuous, wavelet transform, based on Shannon`s sampling theorem in frequency space, has been developed for use with continuous mother wavelets and sampled data sets. The method differs from the usual discrete-wavelet approach and the continuous-wavelet transform in that, here, the wavelet is sampled in the frequency domain. Since Shannon`s sampling theorem lets us view the Fourier transform of the data set as a continuous function in frequency space, the continuous nature of the functions is kept up to the point of sampling the scale-translation lattice, so the scale-translation grid used to represent the wavelet transform is independent of the time- domain sampling of the signal under analysis. Computational cost and nonorthogonality aside, the inherent flexibility and shift invariance of the frequency-space wavelets has advantages. The method has been applied to forensic audio reconstruction speaker recognition/identification, and the detection of micromotions of heavy vehicles associated with ballistocardiac impulses originating from occupants` heart beats. Audio reconstruction is aided by selection of desired regions in the 2-D representation of the magnitude of the transformed signal. The inverse transform is applied to ridges and selected regions to reconstruct areas of interest, unencumbered by noise interference lying outside these regions. To separate micromotions imparted to a mass-spring system (e.g., a vehicle) by an occupants beating heart from gross mechanical motions due to wind and traffic vibrations, a continuous frequency-space wavelet, modeled on the frequency content of a canonical ballistocardiogram, was used to analyze time series taken from geophone measurements of vehicle micromotions. By using a family of mother wavelets, such as a set of Gaussian derivatives of various orders, features such as the glottal closing rate and word and phrase segmentation may be extracted from voice data.

Mitigation of voltage sag, swell and power factor correction using solid-state transformer b

Directory of Open Access Journals (Sweden)

M.R. Banaei

2014-09-01

Full Text Available This paper presents a novel topology of solid-state transformer (SST. In the design process, the AC/DC, DC/AC and AC/AC converters have been integrated to achieve higher efficiency. To obtain higher efficiency from other SST with DC-link topologies, the AC/DC and DC/AC converters have been integrated in one matrix converter. The proposed SST performs typical functions and has advantages such as power factor correction, voltage sag and swell elimination, voltage flicker reduction and protection capability in fault situations. In addition, it has other benefits such as light weight, low volume and elimination of hazardous liquid dielectrics because it uses medium frequency transformer. The operation and some performances of the proposed SST have been verified by the simulation results.

Selection of the wavelet function for the frequencies estimation

International Nuclear Information System (INIS)

Garcia R, A.

2007-01-01

At the moment the signals are used to diagnose the state of the systems, by means of the extraction of their more important characteristics such as the frequencies, tendencies, changes and temporary evolutions. This characteristics are detected by means of diverse analysis techniques, as Autoregressive methods, Fourier Transformation, Fourier transformation in short time, Wavelet transformation, among others. The present work uses the one Wavelet transformation because it allows to analyze stationary, quasi-stationary and transitory signals in the time-frequency plane. It also describes a methodology to select the scales and the Wavelet function to be applied the one Wavelet transformation with the objective of detecting to the dominant system frequencies. (Author)

Time-Frequency-Wavenumber Analysis of Surface Waves Using the Continuous Wavelet Transform

Science.gov (United States)

Poggi, V.; Fäh, D.; Giardini, D.

2013-03-01

A modified approach to surface wave dispersion analysis using active sources is proposed. The method is based on continuous recordings, and uses the continuous wavelet transform to analyze the phase velocity dispersion of surface waves. This gives the possibility to accurately localize the phase information in time, and to isolate the most significant contribution of the surface waves. To extract the dispersion information, then, a hybrid technique is applied to the narrowband filtered seismic recordings. The technique combines the flexibility of the slant stack method in identifying waves that propagate in space and time, with the resolution of f- k approaches. This is particularly beneficial for higher mode identification in cases of high noise levels. To process the continuous wavelet transform, a new mother wavelet is presented and compared to the classical and widely used Morlet type. The proposed wavelet is obtained from a raised-cosine envelope function (Hanning type). The proposed approach is particularly suitable when using continuous recordings (e.g., from seismological-like equipment) since it does not require any hardware-based source triggering. This can be subsequently done with the proposed method. Estimation of the surface wave phase delay is performed in the frequency domain by means of a covariance matrix averaging procedure over successive wave field excitations. Thus, no record stacking is necessary in the time domain and a large number of consecutive shots can be used. This leads to a certain simplification of the field procedures. To demonstrate the effectiveness of the method, we tested it on synthetics as well on real field data. For the real case we also combine dispersion curves from ambient vibrations and active measurements.

Real-time and high accuracy frequency measurements for intermediate frequency narrowband signals

Science.gov (United States)

Tian, Jing; Meng, Xiaofeng; Nie, Jing; Lin, Liwei

2018-01-01

Real-time and accurate measurements of intermediate frequency signals based on microprocessors are difficult due to the computational complexity and limited time constraints. In this paper, a fast and precise methodology based on the sigma-delta modulator is designed and implemented by first generating the twiddle factors using the designed recursive scheme. This scheme requires zero times of multiplications and only half amounts of addition operations by using the discrete Fourier transform (DFT) and the combination of the Rife algorithm and Fourier coefficient interpolation as compared with conventional methods such as DFT and Fast Fourier Transform. Experimentally, when the sampling frequency is 10 MHz, the real-time frequency measurements with intermediate frequency and narrowband signals have a measurement mean squared error of ±2.4 Hz. Furthermore, a single measurement of the whole system only requires approximately 0.3 s to achieve fast iteration, high precision, and less calculation time.

Transformers and the Electric Utility System

Science.gov (United States)

Roman, Harry T.

2005-01-01

For electric energy to get from the generating station to a home, it must pass through a transformer, a device that can change voltage levels easily. This article describes how transformers work, covering the following topics: (1) the magnetism-electricity link; (2) transformer basics; (3) the energy seesaw; (4) the turns ratio rule; and (5)…

High-frequency transformation of a methylotrophic yeast, Candida boidinii, with autonomously replicating plasmids which are also functional in Saccharomyces cerevisiae.

Science.gov (United States)

Sakai, Y; Goh, T K; Tani, Y

1993-06-01

We have developed a transformation system which uses autonomous replicating plasmids for a methylotrophic yeast, Candida boidinii. Two autonomous replication sequences, CARS1 and CARS2, were newly cloned from the genome of C. boidinii. Plasmids having both a CARS fragment and the C. boidinii URA3 gene transformed C. boidinii ura3 cells to Ura+ phenotype at frequencies of up to 10(4) CFU/micrograms of DNA. From Southern blot analysis, CARS plasmids seemed to exist in polymeric forms as well as in monomeric forms in C. boidinii cells. The C. boidinii URA3 gene was overexpressed in C. boidinii on these CARS vectors. CARS1 and CARS2 were found to function as an autonomous replicating element in Saccharomyces cerevisiae as well. Different portions of the CARS1 sequence were needed for autonomous replicating activity in C. boidinii and S. cerevisiae. C. boidinii could also be transformed with vectors harboring a CARS fragment and the S. cerevisiae URA3 gene.

Multi-Scale Scattering Transform in Music Similarity Measuring

Science.gov (United States)

Wang, Ruobai

Scattering transform is a Mel-frequency spectrum based, time-deformation stable method, which can be used in evaluating music similarity. Compared with Dynamic time warping, it has better performance in detecting similar audio signals under local time-frequency deformation. Multi-scale scattering means to combine scattering transforms of different window lengths. This paper argues that, multi-scale scattering transform is a good alternative of dynamic time warping in music similarity measuring. We tested the performance of multi-scale scattering transform against other popular methods, with data designed to represent different conditions.

Treatment of electrochemical noise data by the Hilbert-Huang transform

International Nuclear Information System (INIS)

Rahier, A.

2009-01-01

Most of the classical approaches for treating electro-chemical noise (ECN) data suffer from the non-linear and non steady-state character of the delivered signal. Very often, the link between time and the local corrosion events supposedly responsible for ECN data signatures is lost during treatment, as is obvious when using the classical Fourier Transform (FT), followed by an analysis of the response in the frequency domain. In this particular case, the information directly related to the corrosion events is distributed into the full spectra, thereby preventing the operator to derive clear and precise conclusions. In 2005, we suggested an alternative data treatment based on the Hilbert-Huang transform (HHT). The latter keeps track of the time variable and copes with non-linear and non steady-state behaviours of the system under examination. In 2006, we demonstrated the applicability of the newly proposed data treatment in the case of ECN data collected under BWR (Boiling Water Reactor) conditions. In 2007, we collected additional ECN data and started a preliminary investigation of two mathematical restrictions that are susceptible to impair the interpretation of the results. We discovered a possible modification of the Hilbert transform allowing generating controlled phase shifts that are different from pi/2 as is always the case for the Hilbert transform

Development of high frequency spice models for ferrite core inductors and transformers

Science.gov (United States)

Muyshondt, G. Patrick; Portnoy, William M.

In this work high frequency SPICE models were developed to simulate the hysteresis and saturation effects of toroidal shaped ferrite core inductors and transformers. The models include the nonlinear, multi-valued B-H characteristic of the core material, leakage flux, stray capacitances, and core losses. The saturation effects were modeled using two diode clamping arrangements in conjunction with nonlinear dependent sources. Two possible controlling schemes were developed for the saturation switch. One of the arrangements used the current flowing through a series RC branch to control the switch, while the other used a NAND gate. The NAND gate implementation of the switch proved to be simpler and the parameters associated with it were easier to determine from the measurements and the B-H characteristics of the material. Lumped parameters were used to simulate the parasitic effects. Techniques for measuring these effects are described. The models were verified using manganese-zinc ferrite-type toroidal cores and they have general applicability to all circuit analysis codes equivalent function blocks such as multipliers, adders, and logic components.

Entropy change linked to the martensitic transformation inmetamagnetic shape memory alloys

Czech Academy of Sciences Publication Activity Database

Recarte, V.; Pérez-Landazábal, J.I.; Sánchez-Alarcos, V.; Zablotskyy, Vitaliy A.; Cesari, E.; Kustov, S.

2012-01-01

Roč. 60, 6-7 (2012), s. 3168-3175 ISSN 1359-6454 Institutional support: RVO:68378271 Keywords : metamagnetic shape memory alloys (MSMAs) * martensitic phase transformation * thermodynamics * transformation entropy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.941, year: 2012

Serial CT and MRI of ischaemic cerebral infarcts: frequency and clinical impact of haemorrhagic transformation

Energy Technology Data Exchange (ETDEWEB)

Mayer, T.E.; Brueckmann, H. [Muenchen Univ. (Germany). Abt. fuer Neuroradiologie; Schulte-Altedorneburg, G. [Dept. of Radiology/Neuroradiology, University Medical School of Luebeck (Germany); Droste, D.W. [Dept. of Neurology, University Medical School of Luebeck (Germany)

2000-04-01

The frequency, predisposing factors and clinical consequences of haemorrhagic infarcts and damaged blood-brain barrier as shown by contrast enhancement (CE) in ischaemic cerebral infarcts are controversial. We prospectively compared the sensitivity of CT and MRI to haemorrhagic transformation (HT) and CE. We also wished to investigate the clinical significance of HT and factors possibly associated with it. We studied 36 patients with acute ischaemic infarcts in the middle cerebral artery territory during the first 2 weeks after the ictus. After CT and rating of the neurological deficit on admission, serial examinations with clinical neuromonitoring, contrast-enhanced CT and MRI were done on the same day. The occurrence and severity of HT were correlated with CE, stroke mechanism, infarct size, development of neurological deficits and antithrombotic treatment. The frequency of HT detected by MRI was 80 %. CE usually preceded HT or was seen simultaneously. MRI had a higher sensitivity than CT to HT and CE. Severity of HT was positively correlated with infarct size (P < 0.01). HT had no influence on patient's neurological status. Neither the type of antithrombotic treatment nor the stroke mechanism was associated with the severity of HT. No parenchymal haemorrhage occurred. (orig.)

Transformation of metal-organic framework to polymer gel by cross-linking the organic ligands preorganized in metal-organic framework.

Science.gov (United States)

Ishiwata, Takumi; Furukawa, Yuki; Sugikawa, Kouta; Kokado, Kenta; Sada, Kazuki

2013-04-10

Until now, seamless fusion of metal-organic frameworks (MOFs) and covalently cross-linked polymer gels (PG) at molecular level has been extremely rare, since these two matters have been regarded as opposite, that is, hard versus soft. In this report, we demonstrate transformation of cubic MOF crystals to PG via inner cross-linking of the organic linkers in the void space of MOF, followed by decomposition of the metal coordination. The obtained PG behaved as a polyelectrolyte gel, indicating the high content of ionic groups inside. Metal ions were well adsorbed in the PG due to its densely packed carboxylate groups. A chimera-type hybrid material consisting of MOF and PG was obtained by partial hydrolysis of resulting cross-linked MOF. The shape of resulting PG network well reflected the crystal structure of MOF employed as a template. Our results will connect the two different network materials that have been ever studied in the two different fields to provide new soft and hard hybrid materials, and the unique copolymerization in the large void space of the MOF will open a new horizon toward "ideal network polymers" never prepared before now.

Exact Solution of Gas Dynamics Equations Through Reduced Differential Transform and Sumudu Transform Linked with Pades Approximants

Science.gov (United States)

Rao, T. R. Ramesh

2018-04-01

In this paper, we study the analytical method based on reduced differential transform method coupled with sumudu transform through Pades approximants. The proposed method may be considered as alternative approach for finding exact solution of Gas dynamics equation in an effective manner. This method does not require any discretization, linearization and perturbation.

ECG denoising with adaptive bionic wavelet transform.

Science.gov (United States)

Sayadi, Omid; Shamsollahi, Mohammad Bagher

2006-01-01

In this paper a new ECG denoising scheme is proposed using a novel adaptive wavelet transform, named bionic wavelet transform (BWT), which had been first developed based on a model of the active auditory system. There has been some outstanding features with the BWT such as nonlinearity, high sensitivity and frequency selectivity, concentrated energy distribution and its ability to reconstruct signal via inverse transform but the most distinguishing characteristic of BWT is that its resolution in the time-frequency domain can be adaptively adjusted not only by the signal frequency but also by the signal instantaneous amplitude and its first-order differential. Besides by optimizing the BWT parameters parallel to modifying a new threshold value, one can handle ECG denoising with results comparing to those of wavelet transform (WT). Preliminary tests of BWT application to ECG denoising were constructed on the signals of MIT-BIH database which showed high performance of noise reduction.

Clifford Fourier transform on vector fields.

Science.gov (United States)

Ebling, Julia; Scheuermann, Gerik

2005-01-01

Image processing and computer vision have robust methods for feature extraction and the computation of derivatives of scalar fields. Furthermore, interpolation and the effects of applying a filter can be analyzed in detail and can be advantages when applying these methods to vector fields to obtain a solid theoretical basis for feature extraction. We recently introduced the Clifford convolution, which is an extension of the classical convolution on scalar fields and provides a unified notation for the convolution of scalar and vector fields. It has attractive geometric properties that allow pattern matching on vector fields. In image processing, the convolution and the Fourier transform operators are closely related by the convolution theorem and, in this paper, we extend the Fourier transform to include general elements of Clifford Algebra, called multivectors, including scalars and vectors. The resulting convolution and derivative theorems are extensions of those for convolution and the Fourier transform on scalar fields. The Clifford Fourier transform allows a frequency analysis of vector fields and the behavior of vector-valued filters. In frequency space, vectors are transformed into general multivectors of the Clifford Algebra. Many basic vector-valued patterns, such as source, sink, saddle points, and potential vortices, can be described by a few multivectors in frequency space.

Transmission system for distribution of video over long-haul optical point-to-point links using a microwave photonic filter in the frequency range of 0.01-10 GHz

Science.gov (United States)

Zaldívar Huerta, Ignacio E.; Pérez Montaña, Diego F.; Nava, Pablo Hernández; Juárez, Alejandro García; Asomoza, Jorge Rodríguez; Leal Cruz, Ana L.

2013-12-01

We experimentally demonstrate the use of an electro-optical transmission system for distribution of video over long-haul optical point-to-point links using a microwave photonic filter in the frequency range of 0.01-10 GHz. The frequency response of the microwave photonic filter consists of four band-pass windows centered at frequencies that can be tailored to the function of the spectral free range of the optical source, the chromatic dispersion parameter of the optical fiber used, as well as the length of the optical link. In particular, filtering effect is obtained by the interaction of an externally modulated multimode laser diode emitting at 1.5 μm associated to the length of a dispersive optical fiber. Filtered microwave signals are used as electrical carriers to transmit TV-signal over long-haul optical links point-to-point. Transmission of TV-signal coded on the microwave band-pass windows located at 4.62, 6.86, 4.0 and 6.0 GHz are achieved over optical links of 25.25 km and 28.25 km, respectively. Practical applications for this approach lie in the field of the FTTH access network for distribution of services as video, voice, and data.

Simulation of beam-splitter made of metamaterials with angle spatial distribution of constitutive parameters based on transformation optics for THz frequency range

International Nuclear Information System (INIS)

Gurvitz, E A; Vozianova, A V; Khodzitsky, M K

2014-01-01

New approach to design beam splitter on basis of the transformation optics using angle constitutive parameters distribution of medium was proposed. The beam splitter was numerically simulated by COMSOL Multiphysics for terahertz frequency range. The numerical simulations were carried out for ideal and reduced constitutive parameters of medium for the case of TM plane wave

The Use of Continuous Wavelet Transform Based on the Fast Fourier Transform in the Analysis of Multi-channel Electrogastrography Recordings.

Science.gov (United States)

Komorowski, Dariusz; Pietraszek, Stanislaw

2016-01-01

This paper presents the analysis of multi-channel electrogastrographic (EGG) signals using the continuous wavelet transform based on the fast Fourier transform (CWTFT). The EGG analysis was based on the determination of the several signal parameters such as dominant frequency (DF), dominant power (DP) and index of normogastria (NI). The use of continuous wavelet transform (CWT) allows for better visible localization of the frequency components in the analyzed signals, than commonly used short-time Fourier transform (STFT). Such an analysis is possible by means of a variable width window, which corresponds to the scale time of observation (analysis). Wavelet analysis allows using long time windows when we need more precise low-frequency information, and shorter when we need high frequency information. Since the classic CWT transform requires considerable computing power and time, especially while applying it to the analysis of long signals, the authors used the CWT analysis based on the fast Fourier transform (FFT). The CWT was obtained using properties of the circular convolution to improve the speed of calculation. This method allows to obtain results for relatively long records of EGG in a fairly short time, much faster than using the classical methods based on running spectrum analysis (RSA). In this study authors indicate the possibility of a parametric analysis of EGG signals using continuous wavelet transform which is the completely new solution. The results obtained with the described method are shown in the example of an analysis of four-channel EGG recordings, performed for a non-caloric meal.

One-parameter Darboux transformations in thermodynamics

International Nuclear Information System (INIS)

Rosu, Haret C.

2002-01-01

The quantum oscillator thermodynamic actions are the conjugate intensive parameters for the frequency in any frequency changing process. These oscillator actions fulfill simple Riccati equations. Interesting Darboux transformations of the fundamental Planck and pure vacuum actions are discussed here in some detail. It is shown that the one-parameter 'Darboux-Transformed-Thermodynamics' refers to superpositions of boson and fermion excitations of positive and negative absolute temperature, respectively. A Darboux generalization of the fluctuation-dissipation theorem is also briefly sketched

Dual Transformer Model based on Standard Circuit Elements for the Study of Low- and Mid-frequency Transients

Science.gov (United States)

Jazebi, Saeed

This thesis is a step forward toward achieving the final objective of creating a fully dual model for transformers including eddy currents and nonlinearities of the iron core using the fundamental electrical components already available in the EMTP-type programs. The model is effective for the study of the performance of transformers during power system transients. This is very important for transformer designers, because the insulation of transformers is determined with the overvoltages caused by lightning or switching operations. There are also internally induced transients that occur when a switch is actuated. For example switching actions for reconfiguration of distribution systems that offers economic advantages, or protective actions to clear faults and large short-circuit currents. Many of the smart grid concepts currently under development by many utilities rely heavily on switching to optimize resources that produce transients in the system. On the other hand, inrush currents produce mechanical forces which deform transformer windings and cause malfunction of the differential protection. Also, transformer performance under ferroresonance and geomagnetic induced currents are necessary to study. In this thesis, a physically consistent dual model applicable to single-phase two-winding transformers is proposed. First, the topology of a dual electrical equivalent circuit is obtained from the direct application of the principle of duality. Then, the model parameters are computed considering the variations of the transformer electromagnetic behavior under various operating conditions. Current modeling techniques use different topological models to represent diverse transient situations. The reversible model proposed in this thesis unifies the terminal and topological equivalent circuits. The model remains invariable for all low-frequency transients including deep saturation conditions driven from any of the two windings. The very high saturation region of the

The Zak transform and some counterexamples in time-frequency analysis

NARCIS (Netherlands)

Janssen, A.J.E.M.

1992-01-01

It is shown how the Zak transform can be used to find nontrivial examples of functions f, g e L2(R) with f × g ¿ 0 ¿ F × G, where F, G are the Fourier transforms of f, g, respectively. This is then used to exhibit a nontrivial pair of functions h, k e L2(R), h ¿ k, such that |h| = |k|, |H| = |K|. A

Simulation and parallel connection of step-down piezoelectric transformers

International Nuclear Information System (INIS)

Thang, Vo Viet; Kim, In Sung; Jeong, Soon Jong; Kim, Min Soo; Song, Jae Sung

2012-01-01

Piezoelectric transformers have been used widely in electronic circuits due to advantages such as high efficiency, miniaturization and no flammability; however the output power has been limited. For overcoming this drawback, some research has recently been focused on connections between piezoelectric transformers. Based on these operations, the output power has been improved compared to the single operation. Parallel operation of step-down piezoelectric transformers is presented in this paper. An important factor affecting the parallel operation of piezoelectric transformer was the resonance frequency, and a small difference in resonance frequencies was obtained with transformers having the same dimensions and fabricating processes. The piezoelectric transformers were found to operate in first radial mode at a frequency of 68 kHz. An equivalent circuit was used to investigate parallel driving of piezoelectric transformers and then to compare the result with experimental observations. The electrical characteristics, including the output voltage, output power and efficient were measured at a matching resistive load. Effects of frequency on the step-down ratio and of the input voltage on the power properties in the simulation were similar to the experimental results. The output power of the parallel operation was 35 W at a load of 50 Ω and an input voltage of 100 V; the temperature rise was 30 .deg. C and the efficiency was 88%.

The linear variable differential transformer (LVDT) position sensor for gravitational wave interferometer low-frequency controls

Energy Technology Data Exchange (ETDEWEB)

Tariq, Hareem E-mail: htariq@ligo.caltech.edu; Takamori, Akiteru; Vetrano, Flavio; Wang Chenyang; Bertolini, Alessandro; Calamai, Giovanni; DeSalvo, Riccardo; Gennai, Alberto; Holloway, Lee; Losurdo, Giovanni; Marka, Szabolcs; Mazzoni, Massimo; Paoletti, Federico; Passuello, Diego; Sannibale, Virginio; Stanga, Ruggero

2002-08-21

Low-power, ultra-high-vacuum compatible, non-contacting position sensors with nanometer resolution and centimeter dynamic range have been developed, built and tested. They have been designed at Virgo as the sensors for low-frequency modal damping of Seismic Attenuation System chains in Gravitational Wave interferometers and sub-micron absolute mirror positioning. One type of these linear variable differential transformers (LVDTs) has been designed to be also insensitive to transversal displacement thus allowing 3D movement of the sensor head while still precisely reading its position along the sensitivity axis. A second LVDT geometry has been designed to measure the displacement of the vertical seismic attenuation filters from their nominal position. Unlike the commercial LVDTs, mostly based on magnetic cores, the LVDTs described here exert no force on the measured structure.

Building a Climate of Change with a link through Transformational Leadership and Corporate Culture: A Management key to a Global Environment

Directory of Open Access Journals (Sweden)

Paul Llwellyn Flemming

2017-03-01

Full Text Available Leaders in the Caribbean Diaspora have argued that there is no documented evidence of the association between the three fundamental pillars of public sector organization: leadership, performance and culture. This cross-culture leadership concern has evoked a series of research which basic aim is to conceptualize the leadership culture phenomenon. The problem is that there is a high degree of dysfunctional leadership within the public sectors organizations in the Caribbean diaspora and there is limited empirical evidence that can be had to validate the reason for this inadequacy. The purpose of this study is to investigate the link between transformational leadership styles, corporate organizational culture types and performance in sixteen public sectors organizations. The methodology implemented in this research is the Multifactor Leadership Questionnaire (MLQ 5X, and the Organizational Culture Assessment Instrument (OCAI to collect data. Seventy-five executive directors completed measures of the MLQ 5x leadership traits and culture types. A total of 200 employees from   across sixteen public sector organizations completed the measures on leadership and culture. The responses were scaled and coded to enable the segmentation of the data into dependent and independent variables based on the leadership, performance and culture variables. The study utilized the multiple regression models and correlation statistical analyses to determine the degree of commonality among the components. The results indicate support for the hypotheses link between the traits of transformational leadership and organizational culture with performance being the mediating variable. Exploratory analysis showed that several executive leaders have leadership traits that support culture values. The study concluded that transformational leadership and corporate organizational culture have positive effects on facilitating performance and is best suited in managing change and

Properties of an improved Gabor wavelet transform and its applications to seismic signal processing and interpretation

Science.gov (United States)

Ji, Zhan-Huai; Yan, Sheng-Gang

2017-12-01

This paper presents an analytical study of the complete transform of improved Gabor wavelets (IGWs), and discusses its application to the processing and interpretation of seismic signals. The complete Gabor wavelet transform has the following properties. First, unlike the conventional transform, the improved Gabor wavelet transform (IGWT) maps time domain signals to the time-frequency domain instead of the time-scale domain. Second, the IGW's dominant frequency is fixed, so the transform can perform signal frequency division, where the dominant frequency components of the extracted sub-band signal carry essentially the same information as the corresponding components of the original signal, and the subband signal bandwidth can be regulated effectively by the transform's resolution factor. Third, a time-frequency filter consisting of an IGWT and its inverse transform can accurately locate target areas in the time-frequency field and perform filtering in a given time-frequency range. The complete IGW transform's properties are investigated using simulation experiments and test cases, showing positive results for seismic signal processing and interpretation, such as enhancing seismic signal resolution, permitting signal frequency division, and allowing small faults to be identified.

Devil’s Vortex Phase Structure as Frequency Plane Mask for Image Encryption Using the Fractional Mellin Transform

Directory of Open Access Journals (Sweden)

Sunanda Vashisth

2014-01-01

Full Text Available A frequency plane phase mask based on Devil’s vortex structure has been used for image encryption using the fractional Mellin transform. The phase key for decryption is obtained by an iterative phase retrieval algorithm. The proposed scheme has been validated for grayscale secret target images, by numerical simulation. The efficacy of the scheme has been evaluated by computing mean-squared-error between the secret target image and the decrypted image. Sensitivity analysis of the decryption process to variations in various encryption parameters has been carried out. The proposed encryption scheme has been seen to exhibit reasonable robustness against occlusion attack.

Wigner distribution and fractional Fourier transform

NARCIS (Netherlands)

Alieva, T.; Bastiaans, M.J.

2001-01-01

The connection between the Wigner distribution and the squared modulus of the fractional Fourier transform - which are both well-known time-frequency representations of a signal - is established. In particular the Radon-Wigner transform is used, which relates projections of the Wigner distribution

The frequency-independent control method for distributed generation systems

DEFF Research Database (Denmark)

Naderi, Siamak; Pouresmaeil, Edris; Gao, Wenzhong David

2012-01-01

In this paper a novel frequency-independent control method suitable for distributed generation (DG) is presented. This strategy is derived based on the . abc/. αβ transformation and . abc/. dq transformation of the ac system variables. The active and reactive currents injected by the DG are contr......In this paper a novel frequency-independent control method suitable for distributed generation (DG) is presented. This strategy is derived based on the . abc/. αβ transformation and . abc/. dq transformation of the ac system variables. The active and reactive currents injected by the DG...

Design and Realization of FIR Filter for Inter Satellite Link at 50-90 MHZ Frequency using FPGA

Directory of Open Access Journals (Sweden)

Yuyu Wahyu

2016-12-01

Full Text Available In this paper, design and realization of FIR filter with a bandwidth of 40 MHz at 50-90 MHz frequency has been proposed. The design was destined to be implemented on the Inter Satellite Links (ISL. This kind of filter had been selected due to a need in linear phase responseon the ISL data communication. Equiripple method was used to design the filter becauseof its reliability in minimizing the magnitude errors. The design of this FIR filter was conducted with theoretical calculation and simulation using the R2012b Matlab. For the implementation, FPGA was used with a VHDL as the programming language with a help of Xilinx ISE Design Suite 14.5. Simulation results in Matlab and Simulink indicated that the filter design could be well implemented on ISL at frequency of 50 MHz - 90 MHz with stopband of 60 db. The phase responseresult of the realized design is quite linear so that the filter is suitable for data communication on the ISL.

Signals and transforms in linear systems analysis

CERN Document Server

Wasylkiwskyj, Wasyl

2013-01-01

Signals and Transforms in Linear Systems Analysis covers the subject of signals and transforms, particularly in the context of linear systems theory. Chapter 2 provides the theoretical background for the remainder of the text. Chapter 3 treats Fourier series and integrals. Particular attention is paid to convergence properties at step discontinuities. This includes the Gibbs phenomenon and its amelioration via the Fejer summation techniques. Special topics include modulation and analytic signal representation, Fourier transforms and analytic function theory, time-frequency analysis and frequency dispersion. Fundamentals of linear system theory for LTI analogue systems, with a brief account of time-varying systems, are covered in Chapter 4 . Discrete systems are covered in Chapters 6 and 7.  The Laplace transform treatment in Chapter 5 relies heavily on analytic function theory as does Chapter 8 on Z -transforms. The necessary background on complex variables is provided in Appendix A. This book is intended to...

Subband/Transform MATLAB Functions For Processing Images

Science.gov (United States)

Glover, D.

1995-01-01

SUBTRANS software is package of routines implementing image-data-processing functions for use with MATLAB*(TM) software. Provides capability to transform image data with block transforms and to produce spatial-frequency subbands of transformed data. Functions cascaded to provide further decomposition into more subbands. Also used in image-data-compression systems. For example, transforms used to prepare data for lossy compression. Written for use in MATLAB mathematical-analysis environment.

Application of the transfer function to recognition of resonance overvoltages in transformer windings

International Nuclear Information System (INIS)

Florkowski, Marek; Furgał, Jakub

2010-01-01

Power transformer insulation systems are subjected to many stresses during normal operation due to lightning and switching. If the spectrum of incoming surge voltage matches the winding one, a corresponding resonance will be excited. Therefore external transients occurring in power systems might trigger internal overvoltages of a large maximum value in transformer windings. Overvoltages having such a character have been the main cause of many power transformer failures. This paper presents a novel approach to the identification of sensitive zones in the transformer windings based on measurements of overvoltages inside the windings and the frequency dependences of admittance of the power transformer. The frequency characteristics of the transformer winding may determine those regions in the frequency spectrum. The presented methodology might be used both for design optimization and diagnostics of power transformers

Effect of temporal distribution of dose on oncogenic transformation

International Nuclear Information System (INIS)

Miller, R.C.; Brenner, D.J.; Geard, C.R.; Marino, S.A.; Hall, E.J.

1988-01-01

Risk estimates for neutron hazards are of considerable social and economic importance. Effectiveness per unit dose of X or γ rays (low-LET radiations) has been consistently observed to be dependent on the temporal distribution of dose. In a series of comparisons, 0.5 Gy of single or fractionated (five fractions in 8 h), neutrons of 0.23, 0.35, 0.45, 5.9, or 13.7 MeV were delivered to a synchronous C3H 10T1/2 cells. Transformation frequencies per surviving cell are shown. Cells exposed to one energy (5.9 MeV) show a significant enhancement at the 95% level due to fractionated exposures, and at the 85% confidence level the 0.35- and 0.45-MeV fractionated exposures additionally result in significantly greater transformation frequencies. The frequencies of surviving cells per dish between a single or fractionated exposure vary by less than 10%. In three of five pairwise comparisons, fractionated exposures result in statistically greater frequencies of transformants per dish, and are in complete agreement with the results when induction is expressed as transformants per surviving cell. However, after 0.23-MeV neutron irradiation, the single dose resulted in a greater incidence of transformed foci than the fractionated dose

Evaluation of optical ZP-OFDM transmission performance in multimode fiber links.

Science.gov (United States)

Medina, Pau; Almenar, Vicenç; Corral, Juan L

2014-01-13

In this paper, the performance of Zero Padding Orthogonal Frequency Division Multiplexing (ZP-OFDM) on intensity modulation-direct detection (IM-DD) multimode fiber (MMF) links is assessed by means of numerical simulations. The performance of ZP-OFDM is compared to classical Cyclic Prefixed form of OFDM (CP-OFDM) which is known to offer a limited performance in terms of symbol recovery in subcarriers suffering severe fading. Simulations results show that ZP-OFDM is able to reach 29 Gbps in 99.5% of all installed MMF links up to 600 meters compared to 14 Gbps for CP-OFDM when a 64 points fast Fourier transform (FFT) size is used. The use of ZP-OFDM makes it possible to increase the link length up to 1200 and 2400 m with a 25 Gbps data rate if the FFT sizes are increased to 128 and 256 points, respectively; whereas the CP-OFDM scheme will offer a maximum data rate of 10 Gbps in both cases. ZP-OFDM can be an alternative to adaptive loading OFDM schemes without the need of a negotiation between transmitter and receiver, reducing the system deployment complexity and increasing the flexibility in scenarios with multiple receivers.

Face recognition using slow feature analysis and contourlet transform

Science.gov (United States)

Wang, Yuehao; Peng, Lingling; Zhe, Fuchuan

2018-04-01

In this paper we propose a novel face recognition approach based on slow feature analysis (SFA) in contourlet transform domain. This method firstly use contourlet transform to decompose the face image into low frequency and high frequency part, and then takes technological advantages of slow feature analysis for facial feature extraction. We named the new method combining the slow feature analysis and contourlet transform as CT-SFA. The experimental results on international standard face database demonstrate that the new face recognition method is effective and competitive.

Frequency Hopping Transceiver Multiplexer

Science.gov (United States)

1983-03-01

ATC 17 ULR IHQ OCLI CPCTR ULTRA HIGH "OQS" UP TO 4X HIGHER THAN BEST INDUS- TRY STANDARD (ATC 100). MICROWAVE POWER, CURRENT. AND 0 RATINGS5...Q"W were assigned to element (FigC-2); which will be modelled into the transformer previously ment td . The center frequencies, "Q", frequency range...of the TD 1288 system. Temperature stability, change with time or storage. Flexure Frequency, or non-linear change over bandwidth. * Humidity

A general theory on frequency and time-frequency analysis of irregularly sampled time series based on projection methods - Part 2: Extension to time-frequency analysis

Science.gov (United States)

Lenoir, Guillaume; Crucifix, Michel

2018-03-01

Geophysical time series are sometimes sampled irregularly along the time axis. The situation is particularly frequent in palaeoclimatology. Yet, there is so far no general framework for handling the continuous wavelet transform when the time sampling is irregular. Here we provide such a framework. To this end, we define the scalogram as the continuous-wavelet-transform equivalent of the extended Lomb-Scargle periodogram defined in Part 1 of this study (Lenoir and Crucifix, 2018). The signal being analysed is modelled as the sum of a locally periodic component in the time-frequency plane, a polynomial trend, and a background noise. The mother wavelet adopted here is the Morlet wavelet classically used in geophysical applications. The background noise model is a stationary Gaussian continuous autoregressive-moving-average (CARMA) process, which is more general than the traditional Gaussian white and red noise processes. The scalogram is smoothed by averaging over neighbouring times in order to reduce its variance. The Shannon-Nyquist exclusion zone is however defined as the area corrupted by local aliasing issues. The local amplitude in the time-frequency plane is then estimated with least-squares methods. We also derive an approximate formula linking the squared amplitude and the scalogram. Based on this property, we define a new analysis tool: the weighted smoothed scalogram, which we recommend for most analyses. The estimated signal amplitude also gives access to band and ridge filtering. Finally, we design a test of significance for the weighted smoothed scalogram against the stationary Gaussian CARMA background noise, and provide algorithms for computing confidence levels, either analytically or with Monte Carlo Markov chain methods. All the analysis tools presented in this article are available to the reader in the Python package WAVEPAL.

Wind turbine transformer admittance characterization based on online time-domain measurements and preliminary results from measurements done in two transformers using a SFRA

DEFF Research Database (Denmark)

Arana Aristi, Iván; Holbøll, Joachim; Nielsen, Arne Hejde

2009-01-01

This paper presents the analysis of online time-domain measurements on the primary and secondary side of a wind turbine transformer in an Offshore Wind Farm (OWF), during one switching operation realized in the collection grid. The frequency characteristics up to 10 kHz of the current and voltage...... signals of each phase were compared and the transformers admittance characteristic was estimated based on these measurements. Based on the results from the previous analysis, it was decided to acquire a Sweep Frequency Response Analyzer (SFRA) to realize detailed transformer measurements. First...... the results from the measurements in a small dry-type transformer under laboratory conditions are presented, and finally the results from a large transformer measured in a in an industrial setting are shown....

Repair-dependent cell radiation survival and transformation: an integrated theory

International Nuclear Information System (INIS)

Sutherland, John C

2014-01-01

The repair-dependent model of cell radiation survival is extended to include radiation-induced transformations. The probability of transformation is presumed to scale with the number of potentially lethal damages that are repaired in a surviving cell or the interactions of such damages. The theory predicts that at doses corresponding to high survival, the transformation frequency is the sum of simple polynomial functions of dose; linear, quadratic, etc, essentially as described in widely used linear-quadratic expressions. At high doses, corresponding to low survival, the ratio of transformed to surviving cells asymptotically approaches an upper limit. The low dose fundamental- and high dose plateau domains are separated by a downwardly concave transition region. Published transformation data for mammalian cells show the high-dose plateaus predicted by the repair-dependent model for both ultraviolet and ionizing radiation. For the neoplastic transformation experiments that were analyzed, the data can be fit with only the repair-dependent quadratic function. At low doses, the transformation frequency is strictly quadratic, but becomes sigmodial over a wider range of doses. Inclusion of data from the transition region in a traditional linear-quadratic analysis of neoplastic transformation frequency data can exaggerate the magnitude of, or create the appearance of, a linear component. Quantitative analysis of survival and transformation data shows good agreement for ultraviolet radiation; the shapes of the transformation components can be predicted from survival data. For ionizing radiations, both neutrons and x-rays, survival data overestimate the transforming ability for low to moderate doses. The presumed cause of this difference is that, unlike UV photons, a single x-ray or neutron may generate more than one lethal damage in a cell, so the distribution of such damages in the population is not accurately described by Poisson statistics. However, the complete

Effect of 8-methoxypsoralen-plus ultraviolet light on cell-virus interaction: the transforming infection; effect of PUVA on the transformation of baby hamster kidney cells by polyma virus

International Nuclear Information System (INIS)

Morhenn, V.B.; Kaye, J.A.

1979-01-01

Pre-treatment of baby hamster kidney (BHK) cells with 8-methoxypsoralen (8-MOP) plus ultraviolet (UV) light enhances the frequency of their transformation by polyoma (Py) virus. Of the doses tested, 0.5 microgram/m1 8-MOP plus 0 . 3 J/cm2 UV-light results in maximal (30-fold) stimulation of viral transformation. 8-MOP alone does not affect viral transformation and UV-light alone causes only a slight increase in the transformation frequency. Thus the drug and light act synergistically in promoting the effect. Treatment of BHK cells with drug plus light without Py infection does not lead to a transformed morphology. A drug-light combination (0 . 01 microgram/m1 8-MOP plus 1 . 2 J/cm2 UV) that inhibits cellular DNA synthesis is 75% of control at 28 hr after treatment results in a 6-fold stimulation of the transformation frequency

Piezoelectric Transformers: An Historical Review

Directory of Open Access Journals (Sweden)

Alfredo Vazquez Carazo

2016-04-01

Full Text Available Piezoelectric transformers (PTs are solid-state devices that transform electrical energy into electrical energy by means of a mechanical vibration. These devices are manufactured using piezoelectric materials that are driven at resonance. With appropriate design and circuitry, it is possible to step up and step down the voltages between the input and output sections of the piezoelectric transformer, without making use of magnetic materials and obtaining excellent conversion efficiencies. The initial concept of a piezoelectric ceramic transformer was proposed by Charles A. Rosen in 1954. Since then, the evolution of piezoelectric transformers through history has been linked to the relevant work of some excellent researchers as well as to the evolution in materials, manufacturing processes, and driving circuit techniques. This paper summarizes the historical evolution of the technology.

Commissioning of the new AGS MMPS transformers

International Nuclear Information System (INIS)

Bajon, E.; Badea, V. S.; Bannon, M.; Bonati, R.; Marneris, I. M.; Porqueddu, R.; Roser, T.; Sandberg, J.; Savatteri, S.

2009-01-01

The Brookhaven AGS Main Magnet Power Supply (MMPS) is a thyristor control supply rated at 5500 Amps. +/-9000 Volts. The peak magnet power is 50 MWatts. The power supply is fed from a motor/generator manufactured by Siemens. During rectify and invert operation the P Bank power supplies are used. During the flattops the F Bank power supplies are used. The P Bank power supplies are fed from two 23 MVA transformers and the F Bank power supplies are fed from two 5.3 MYA transformers. The fundamental frequency of the F Bank power supplies is 1440 Hz, however the fundamental frequency of the P banks was 720 Hz. It was very important to reduce the ripple during rectify to improve polarized proton operations. For this reason and also because the original transformers were 45 years old we replaced these transformers with new ones and we made the fundamental frequency of both P and F banks 1440 Hz. This paper will highlight the major hurdles that were involved during the installation of the new transformers. It will present waveforms while running at different power levels up to 6MW full load. It will show the transition from the F-Bank power supplies to the P-Banks and also show the improvements in ripple made on the P-Bank power supplies

Commissioning of the new AGS MMPS transformers

Energy Technology Data Exchange (ETDEWEB)

Bajon,E.; Badea, V. S.; Bannon, M.; Bonati, R.; Marneris, I. M.; Porqueddu, r.; Roser, T.; Sandberg, J.; Savatteri, S.

2009-05-04

The Brookhaven AGS Main Magnet Power Supply (MMPS) is a thyristor control supply rated at 5500 Amps. +/-9000 Volts. The peak magnet power is 50 MWatts. The power supply is fed from a motor/generator manufactured by Siemens. During rectify and invert operation the P Bank power supplies are used. During the flattops the F Bank power supplies are used. The P Bank power supplies are fed from two 23 MVA transformers and the F Bank power supplies are fed from two 5.3 MYA transformers. The fundamental frequency of the F Bank power supplies is 1440 Hz, however the fundamental frequency of the P banks was 720 Hz. It was very important to reduce the ripple during rectify to improve polarized proton operations. For this reason and also because the original transformers were 45 years old we replaced these transformers with new ones and we made the fundamental frequency of both P and F banks 1440 Hz. This paper will highlight the major hurdles that were involved during the installation of the new transformers. It will present waveforms while running at different power levels up to 6MW full load. It will show the transition from the F-Bank power supplies to the P-Banks and also show the improvements in ripple made on the P-Bank power supplies.

Radio-frequency transparent demodulation for broadband hybrid wireless-optical links

DEFF Research Database (Denmark)

Zibar, Darko; Sambaraju, Rakesh; Alemany, Ruben

2010-01-01

A novel demodulation technique which is transparent to radio-frequency (RF) carrier frequency is presented and experimentally demonstrated for multigigabit wireless signals. The presented demodulation technique employs optical single-sideband filtering, coherent detection, and baseband digital si...

Recent trends in the condition monitoring of transformers theory, implementation and analysis

CERN Document Server

Chakravorti, Sivaji; Chatterjee, Biswendu

2013-01-01

Recent Trends in the Condition Monitoring of Transformers reflects the current interest in replacing traditional techniques used in power transformer condition monitoring with non-invasive measures such as polarization/depolarization current measurement, recovery voltage measurement, frequency domain spectroscopy and frequency response analysis. The book stresses the importance of scrutinizing the condition of transformer insulation which may fail under present day conditions of intensive use with the resulting degradation of dielectric properties causing functional failure of the transformer.

Multifunctional fiber-optic microwave links based on remote heterodyne detection

DEFF Research Database (Denmark)

Gliese, Ulrik Bo; Nielsen, Torben Nørskov; Nielsen, Søren Nørskov

1998-01-01

The multifunctionality of microwave links based on remote heterodyne detection (RHD) of signals from a dual-frequency laser transmitter is discussed and experimentally demonstrated in this paper. Typically, direct detection (DD) in conjunction with optical intensity modulation is used to implement...... fiber-optic microwave links. The resulting links are inherently transparent. As opposed to DD links, RHD links can perform radio-system functionalities such as modulation and frequency conversion in addition to transparency. All of these three functionalities are presented and experimentally...

Two-dimensional fourier transform spectrometer

Science.gov (United States)

DeFlores, Lauren; Tokmakoff, Andrei

2013-09-03

The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.

Quantifying and resolving multiple vector transformants in S. cerevisiae plasmid libraries.

Science.gov (United States)

Scanlon, Thomas C; Gray, Elizabeth C; Griswold, Karl E

2009-11-20

In addition to providing the molecular machinery for transcription and translation, recombinant microbial expression hosts maintain the critical genotype-phenotype link that is essential for high throughput screening and recovery of proteins encoded by plasmid libraries. It is known that Escherichia coli cells can be simultaneously transformed with multiple unique plasmids and thusly complicate recombinant library screening experiments. As a result of their potential to yield misleading results, bacterial multiple vector transformants have been thoroughly characterized in previous model studies. In contrast to bacterial systems, there is little quantitative information available regarding multiple vector transformants in yeast. Saccharomyces cerevisiae is the most widely used eukaryotic platform for cell surface display, combinatorial protein engineering, and other recombinant library screens. In order to characterize the extent and nature of multiple vector transformants in this important host, plasmid-born gene libraries constructed by yeast homologous recombination were analyzed by DNA sequencing. It was found that up to 90% of clones in yeast homologous recombination libraries may be multiple vector transformants, that on average these clones bear four or more unique mutant genes, and that these multiple vector cells persist as a significant proportion of library populations for greater than 24 hours during liquid outgrowth. Both vector concentration and vector to insert ratio influenced the library proportion of multiple vector transformants, but their population frequency was independent of transformation efficiency. Interestingly, the average number of plasmids born by multiple vector transformants did not vary with their library population proportion. These results highlight the potential for multiple vector transformants to dominate yeast libraries constructed by homologous recombination. The previously unrecognized prevalence and persistence of multiply

Quantifying and resolving multiple vector transformants in S. cerevisiae plasmid libraries

Directory of Open Access Journals (Sweden)

Gray Elizabeth C

2009-11-01

Full Text Available Abstract Background In addition to providing the molecular machinery for transcription and translation, recombinant microbial expression hosts maintain the critical genotype-phenotype link that is essential for high throughput screening and recovery of proteins encoded by plasmid libraries. It is known that Escherichia coli cells can be simultaneously transformed with multiple unique plasmids and thusly complicate recombinant library screening experiments. As a result of their potential to yield misleading results, bacterial multiple vector transformants have been thoroughly characterized in previous model studies. In contrast to bacterial systems, there is little quantitative information available regarding multiple vector transformants in yeast. Saccharomyces cerevisiae is the most widely used eukaryotic platform for cell surface display, combinatorial protein engineering, and other recombinant library screens. In order to characterize the extent and nature of multiple vector transformants in this important host, plasmid-born gene libraries constructed by yeast homologous recombination were analyzed by DNA sequencing. Results It was found that up to 90% of clones in yeast homologous recombination libraries may be multiple vector transformants, that on average these clones bear four or more unique mutant genes, and that these multiple vector cells persist as a significant proportion of library populations for greater than 24 hours during liquid outgrowth. Both vector concentration and vector to insert ratio influenced the library proportion of multiple vector transformants, but their population frequency was independent of transformation efficiency. Interestingly, the average number of plasmids born by multiple vector transformants did not vary with their library population proportion. Conclusion These results highlight the potential for multiple vector transformants to dominate yeast libraries constructed by homologous recombination. The

A fast butterfly algorithm for generalized Radon transforms

KAUST Repository

Hu, Jingwei; Fomel, Sergey; Demanet, Laurent; Ying, Lexing

2013-01-01

Generalized Radon transforms, such as the hyperbolic Radon transform, cannot be implemented as efficiently in the frequency domain as convolutions, thus limiting their use in seismic data processing. We have devised a fast butterfly algorithm

Analysis of two dimensional signals via curvelet transform

Science.gov (United States)

Lech, W.; Wójcik, W.; Kotyra, A.; Popiel, P.; Duk, M.

2007-04-01

This paper describes an application of curvelet transform analysis problem of interferometric images. Comparing to two-dimensional wavelet transform, curvelet transform has higher time-frequency resolution. This article includes numerical experiments, which were executed on random interferometric image. In the result of nonlinear approximations, curvelet transform obtains matrix with smaller number of coefficients than is guaranteed by wavelet transform. Additionally, denoising simulations show that curvelet could be a very good tool to remove noise from images.

Elasticity analysis by MR elastography using the instantaneous frequency method

International Nuclear Information System (INIS)

Oshiro, Osamu; Suga, Mikio; Minato, Kotaro; Okamoto, Jun; Takizawa, Osamu; Matsuda, Tetsuya; Komori, Masaru; Takahashi, Takashi

2000-01-01

This paper describes a calculation method for estimating the elasticity of human organs using magnetic resonance elastography (MRE) images. The method is based on the instantaneous frequency method, which is very sensitive to noise. Therefore, the proposed method also incorporates a noise-reduction function. In the instantaneous frequency method, Fourier transform is applied to the measurement signal. Then, inverse Fourier transform is performed after the negative frequency component is set to zero. In the proposed method, noise is reduced by processing in which the positive higher frequency component is also set to zero before inverse Fourier transform is performed. First, we conducted a simulation study and confirmed the applicability of this method and the noise reduction function. Next, we carried out a phantom experiment and demonstrated that elasticity images could be generated, with the gray level corresponding to the local frequency in MRE images. (author)

Wideband FM Demodulation and Multirate Frequency Transformations

Science.gov (United States)

2016-12-15

Noble identities to extend the proposed approach to larger wideband to narrowband conversion factors and more practical implementations. We further...framework . . . . . . . . . . . . . . . . . . . . . 8 2 Block diagrams of the alternative MFT system for large conversion factors (a) and the Noble Identity ...of both MFT frameworks with conversion factor R = 128 and normalized radian frequency shift wd = 0.1π under the extreme senario with modulation index

Automated reconstruction of pre-transformation microstructures in zirconium

International Nuclear Information System (INIS)

Krishna, K.V. Mani; Tripathi, P.; Hiwarkar, V.D.; Pant, P.; Samajdar, I.; Srivastava, D.; Dey, G.K.

2010-01-01

An automated reconstruction of the pre-transformation microstructure from the microtexture data of the post-transformation product phase is proposed. The method involves identifying triplets of neighboring product grains with a common variant and linking such neighboring triplets via a generalized misorientation criterion. The approach is non-iterative and extremely efficient computationally. The method was tested successfully for different post-transformation microstructures in zirconium.

Transformation of the Zagreb urban region

Directory of Open Access Journals (Sweden)

Milan Ilić

2004-01-01

Full Text Available Several aspects of the transformation of theZagreb urban region are considered in this work: change in the regionćssize and form, socio-economic transformation, functional transformation andphysiognomic or morphological transformation. It was established that theregionćs form has changed: it is moving from the classic star-like form,characteristic of the early developmental phase of the urban region, to acircular form. The region has experienced evolution in the developmentalsense and reached a phase of absolute decentralization. The process oftransformation in the region is continuing at full pace, while onlyperipheral, mainly small and poorly linked settlements with an unfavorabledemographic balance and processes are lagging behind.

[Continuum based fast Fourier transform processing of infrared spectrum].

Science.gov (United States)

Liu, Qing-Jie; Lin, Qi-Zhong; Wang, Qin-Jun; Li, Hui; Li, Shuai

2009-12-01

To recognize ground objects with infrared spectrum, high frequency noise removing is one of the most important phases in spectrum feature analysis and extraction. A new method for infrared spectrum preprocessing was given combining spectrum continuum processing and Fast Fourier Transform (CFFT). Continuum was firstly removed from the noise polluted infrared spectrum to standardize hyper-spectra. Then the spectrum was transformed into frequency domain (FD) with fast Fourier transform (FFT), separating noise information from target information After noise eliminating from useful information with a low-pass filter, the filtered FD spectrum was transformed into time domain (TD) with fast Fourier inverse transform. Finally the continuum was recovered to the spectrum, and the filtered infrared spectrum was achieved. Experiment was performed for chlorite spectrum in USGS polluted with two kinds of simulated white noise to validate the filtering ability of CFFT by contrast with cubic function of five point (CFFP) in time domain and traditional FFT in frequency domain. A circle of CFFP has limited filtering effect, so it should work much with more circles and consume more time to achieve better filtering result. As for conventional FFT, Gibbs phenomenon has great effect on preprocessing result at edge bands because of special character of rock or mineral spectra, while works well at middle bands. Mean squared error of CFFT is 0. 000 012 336 with cut-off frequency of 150, while that of FFT and CFFP is 0. 000 061 074 with cut-off frequency of 150 and 0.000 022 963 with 150 working circles respectively. Besides the filtering result of CFFT can be improved by adjusting the filter cut-off frequency, and has little effect on working time. The CFFT method overcomes the Gibbs problem of FFT in spectrum filtering, and can be more convenient, dependable, and effective than traditional TD filter methods.

Study on time-frequency analysis method of very fast transient overvoltage

Science.gov (United States)

Li, Shuai; Liu, Shiming; Huang, Qiyan; Fu, Chuanshun

2018-04-01

The operation of the disconnector in the gas insulated substation (GIS) may produce very fast transient overvoltage (VFTO), which has the characteristics of short rise time, short duration, high amplitude and rich frequency components. VFTO can cause damage to GIS and secondary equipment, and the frequency components contained in the VFTO can cause resonance overvoltage inside the transformer, so it is necessary to study the spectral characteristics of the VFTO. From the perspective of signal processing, VFTO is a kind of non-stationary signal, the traditional Fourier transform is difficult to describe its frequency which changes with time, so it is necessary to use time-frequency analysis to analyze VFTO spectral characteristics. In this paper, we analyze the performance of short time Fourier transform (STFT), Wigner-Ville distribution (WVD), pseudo Wigner-Ville distribution (PWVD) and smooth pseudo Wigner-Ville distribution (SPWVD). The results show that SPWVD transform is the best. The time-frequency aggregation of SPWVD is higher than STFT, and it does not have cross-interference terms, which can meet the requirements of VFTO spectrum analysis.

Dynamics of fluidic devices with applications to rotor pitch links

Science.gov (United States)

Scarborough, Lloyd H., III

Coupling a Fluidic Flexible Matrix Composite (F2MC) to an air-pressurized fluid port produces a fundamentally new class of tunable vibration isolator. This fluidlastic device provides significant vibration reduction at an isolation frequency that can be tuned over a broad frequency range. The material properties and geometry of the F2MC element, as well as the port inertance, determine the isolation frequency. A unique feature of this device is that the port inertance depends on pressure so the isolation frequency can be adjusted by changing the air pressure. For constant port inertance, the isolation frequency is largely independent of the isolated mass so the device is robust to changes in load. A nonlinear model is developed to predict isolator length and port inertance. The model is linearized and the frequency response calculated. Experiments agree with theory, demonstrating a tunable isolation range from 9 Hz to 36 Hz and transmitted force reductions of up to 60 dB at the isolation frequency. Replacing rigid pitch links on rotorcraft with coupled fluidic devices has the potential to reduce the aerodynamic blade loads transmitted through the pitch links to the swashplate. Analytical models of two fluidic devices coupled with three different fluidic circuits are derived. These passive fluidlastic systems are tuned, by varying the fluid inertances and capacitances of each fluidic circuit, to reduce the transmitted pitch-link loads. The different circuit designs result in transmitted pitch link loads reduction at up to three main rotor harmonics. The simulation results show loads reduction at the targeted out-of-phase and in-phase harmonics of up to 88% and 93%, respectively. Experimental validation of two of the fluidic circuits demonstrates loads reduction of up to 89% at the out-of-phase isolation frequencies and up to 81% at the in-phase isolation frequencies. Replacing rigid pitch links on rotorcraft with fluidic pitch links changes the blade torsional

Prediction of rain effects on earth-space communication links operating in the 10 to 35 GHz frequency range

Science.gov (United States)

Stutzman, Warren L.

1989-01-01

This paper reviews the effects of precipitation on earth-space communication links operating the 10 to 35 GHz frequency range. Emphasis is on the quantitative prediction of rain attenuation and depolarization. Discussions center on the models developed at Virginia Tech. Comments on other models are included as well as literature references to key works. Also included is the system level modeling for dual polarized communication systems with techniques for calculating antenna and propagation medium effects. Simple models for the calculation of average annual attenuation and cross-polarization discrimination (XPD) are presented. Calculation of worst month statistics are also presented.

A fast butterfly algorithm for generalized Radon transforms

KAUST Repository

Hu, Jingwei

2013-06-21

Generalized Radon transforms, such as the hyperbolic Radon transform, cannot be implemented as efficiently in the frequency domain as convolutions, thus limiting their use in seismic data processing. We have devised a fast butterfly algorithm for the hyperbolic Radon transform. The basic idea is to reformulate the transform as an oscillatory integral operator and to construct a blockwise lowrank approximation of the kernel function. The overall structure follows the Fourier integral operator butterfly algorithm. For 2D data, the algorithm runs in complexity O(N2 log N), where N depends on the maximum frequency and offset in the data set and the range of parameters (intercept time and slowness) in the model space. From a series of studies, we found that this algorithm can be significantly more efficient than the conventional time-domain integration. © 2013 Society of Exploration Geophysicists.

Imaging ultrasonic dispersive guided wave energy in long bones using linear radon transform.

Science.gov (United States)

Tran, Tho N H T; Nguyen, Kim-Cuong T; Sacchi, Mauricio D; Le, Lawrence H

2014-11-01

Multichannel analysis of dispersive ultrasonic energy requires a reliable mapping of the data from the time-distance (t-x) domain to the frequency-wavenumber (f-k) or frequency-phase velocity (f-c) domain. The mapping is usually performed with the classic 2-D Fourier transform (FT) with a subsequent substitution and interpolation via c = 2πf/k. The extracted dispersion trajectories of the guided modes lack the resolution in the transformed plane to discriminate wave modes. The resolving power associated with the FT is closely linked to the aperture of the recorded data. Here, we present a linear Radon transform (RT) to image the dispersive energies of the recorded ultrasound wave fields. The RT is posed as an inverse problem, which allows implementation of the regularization strategy to enhance the focusing power. We choose a Cauchy regularization for the high-resolution RT. Three forms of Radon transform: adjoint, damped least-squares, and high-resolution are described, and are compared with respect to robustness using simulated and cervine bone data. The RT also depends on the data aperture, but not as severely as does the FT. With the RT, the resolution of the dispersion panel could be improved up to around 300% over that of the FT. Among the Radon solutions, the high-resolution RT delineated the guided wave energy with much better imaging resolution (at least 110%) than the other two forms. The Radon operator can also accommodate unevenly spaced records. The results of the study suggest that the high-resolution RT is a valuable imaging tool to extract dispersive guided wave energies under limited aperture. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Pupil Dilation and EEG Alpha Frequency Band Power Reveal Load on Executive Functions for Link-Selection Processes during Text Reading.

Directory of Open Access Journals (Sweden)

Christian Scharinger

Full Text Available Executive working memory functions play a central role in reading comprehension. In the present research we were interested in additional load imposed on executive functions by link-selection processes during computer-based reading. For obtaining process measures, we used a methodology of concurrent electroencephalographic (EEG and eye-tracking data recording that allowed us to compare epochs of pure text reading with epochs of hyperlink-like selection processes in an online reading situation. Furthermore, this methodology allowed us to directly compare the two physiological load-measures EEG alpha frequency band power and pupil dilation. We observed increased load on executive functions during hyperlink-like selection processes on both measures in terms of decreased alpha frequency band power and increased pupil dilation. Surprisingly however, the two measures did not correlate. Two additional experiments were conducted that excluded potential perceptual, motor, or structural confounds. In sum, EEG alpha frequency band power and pupil dilation both turned out to be sensitive measures for increased load during hyperlink-like selection processes in online text reading.

Application of wavelet transform to seismic data; Wavelet henkan no jishin tansa eno tekiyo

Energy Technology Data Exchange (ETDEWEB)

Nakagami, K; Murayama, R; Matsuoka, T [Japan National Oil Corp., Tokyo (Japan)

1996-05-01

Introduced herein is the use of the wavelet transform in the field of seismic exploration. Among applications so far made, there are signal filtering, break point detection, data compression, and the solution of finite differential equations in the wavelet domain. In the field of data compression in particular, some examples of practical application have been introduced already. In seismic exploration, it is expected that the wavelet transform will separate signals and noises in data in a way different from the Fourier transform. The continuous wavelet transform displays time change in frequency easy to read, but is not suitable for the analysis and processing large quantities of data. On the other hand, the discrete wavelet transform, being an orthogonal transform, can handle large quantities of data. As compared with the conventional Fourier transform that handles only the frequency domain, the wavelet transform handles the time domain as well as the frequency domain, and therefore is more convenient in handling unsteady signals. 9 ref., 8 figs.

X-radiation-induced transformation in a C3H mouse embryo-derived cell line

International Nuclear Information System (INIS)

Terzaghi, M.; Little, J.B.

1976-01-01

Reproducible x-ray-induced oncogenic transformation has been demonstrated in an established cell line of mouse embryo fibroblasts. Cells derived from transformed foci formed malignant tumors when injected into syngeneic hosts. An exponential increase in the number of transformants per viable cell occurred with doses of up to 400 rads of x-radiation. The transformation frequency in exponentially growing cultures remained constant at 2.3 x 10 -3 following doses of 400 to 1500 rads. There was little change in survival following x-ray doses up to 300 rads. Doses greater than 300 rads were associated with an exponential decline in survival; the D 0 for the survival curve was 175 rads. Transformation frequency varied with changes in the number of viable cells seeded per dish. There was about a 10-fold decline in the transformation frequency when the number of cells was increased from 400 to 1000 viable cells/100-mm Petri dish. Below this density range there was little change in transformation frequency. The presence of lethally preirradiated cells was not associated with an enhancement of transformation in irradiated cells or with the induction of transformation in unirradiated cell cultures. Amphotericin B (Fungizone) inhibited the appearance of transformants when added to the culture medium within 2 to 3 weeks after initiation of the experiment

Linear transformer driver for pulse generation

Science.gov (United States)

Kim, Alexander A; Mazarakis, Michael G; Sinebryukhov, Vadim A; Volkov, Sergey N; Kondratiev, Sergey S; Alexeenko, Vitaly M; Bayol, Frederic; Demol, Gauthier; Stygar, William A

2015-04-07

A linear transformer driver includes at least one ferrite ring positioned to accept a load. The linear transformer driver also includes a first power delivery module that includes a first charge storage devices and a first switch. The first power delivery module sends a first energy in the form of a first pulse to the load. The linear transformer driver also includes a second power delivery module including a second charge storage device and a second switch. The second power delivery module sends a second energy in the form of a second pulse to the load. The second pulse has a frequency that is approximately three times the frequency of the first pulse. The at least one ferrite ring is positioned to force the first pulse and the second pulse to the load by temporarily isolating the first pulse and the second pulse from an electrical ground.

Analysis of the High-Frequency Content in Human QRS Complexes by the Continuous Wavelet Transform: An Automatized Analysis for the Prediction of Sudden Cardiac Death.

Science.gov (United States)

García Iglesias, Daniel; Roqueñi Gutiérrez, Nieves; De Cos, Francisco Javier; Calvo, David

2018-02-12

Fragmentation and delayed potentials in the QRS signal of patients have been postulated as risk markers for Sudden Cardiac Death (SCD). The analysis of the high-frequency spectral content may be useful for quantification. Forty-two consecutive patients with prior history of SCD or malignant arrhythmias (patients) where compared with 120 healthy individuals (controls). The QRS complexes were extracted with a modified Pan-Tompkins algorithm and processed with the Continuous Wavelet Transform to analyze the high-frequency content (85-130 Hz). Overall, the power of the high-frequency content was higher in patients compared with controls (170.9 vs. 47.3 10³nV²Hz -1 ; p = 0.007), with a prolonged time to reach the maximal power (68.9 vs. 64.8 ms; p = 0.002). An analysis of the signal intensity (instantaneous average of cumulative power), revealed a distinct function between patients and controls. The total intensity was higher in patients compared with controls (137.1 vs. 39 10³nV²Hz -1 s -1 ; p = 0.001) and the time to reach the maximal intensity was also prolonged (88.7 vs. 82.1 ms; p content of the QRS complexes was distinct between patients at risk of SCD and healthy controls. The wavelet transform is an efficient tool for spectral analysis of the QRS complexes that may contribute to stratification of risk.

Time-frequency analysis and harmonic Gaussian functions

International Nuclear Information System (INIS)

Ranaivoson, R.T.R; Raoelina Andriambololona; Hanitriarivo, R.

2013-01-01

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

Frequency encoding in renal blood flow regulation

DEFF Research Database (Denmark)

Marsh, D.J.; Sosnovtseva, Olga; Pavlov, A.N.

2005-01-01

With a model of renal blood flow regulation, we examined consequences of tubuloglomerular feedback (TGF) coupling to the myogenic mechanism via voltage-gated Ca channels. The model reproduces the characteristic oscillations of the two mechanisms and predicts frequency and amplitude modulation...... of the myogenic oscillation by TGF. Analysis by wavelet transforms of single-nephron blood flow confirms that both amplitude and frequency of the myogenic oscillation are modulated by TGF. We developed a double-wavelet transform technique to estimate modulation frequency. Median value of the ratio of modulation...... TGF cycle to the next. We used a blood pressure signal recorded by telemetry from a conscious rat as the input to the model. Blood pressure fluctuations induced variability in the modulation records similar to those found in the nephron blood flow results. Frequency and amplitude modulation can...

Materializing the web of linked data

CERN Document Server

Konstantinou, Nikolaos

2015-01-01

This book explains the Linked Data domain by adopting a bottom-up approach: it introduces the fundamental Semantic Web technologies and building blocks, which are then combined into methodologies and end-to-end examples for publishing datasets as Linked Data, and use cases that harness scholarly information and sensor data. It presents how Linked Data is used for web-scale data integration, information management and search. Special emphasis is given to the publication of Linked Data from relational databases as well as from real-time sensor data streams. The authors also trace the transformation from the document-based World Wide Web into a Web of Data. Materializing the Web of Linked Data is addressed to researchers and professionals studying software technologies, tools and approaches that drive the Linked Data ecosystem, and the Web in general.

Efficient Algorithms for the Discrete Gabor Transform with a Long Fir Window

DEFF Research Database (Denmark)

Søndergaard, Peter Lempel

2012-01-01

The Discrete Gabor Transform (DGT) is the most commonly used signal transform for signal analysis and synthesis using a linear frequency scale. The development of the Linear Time-Frequency Analysis Toolbox (LTFAT) has been based on a detailed study of many variants of the relevant algorithms. As ...

Developing a survey instrument to assess the readiness of primary care data, genetic and disease registries to conduct linked research: TRANSFoRm International Research Readiness (TIRRE survey instrument

Directory of Open Access Journals (Sweden)

Emily Leppenwell

2013-05-01

Full Text Available Background Clinical data are collected for routine care in family practice; there are also a growing number of genetic and cancer registry data repositories. The Translational Research and Patient Safety in Europe (TRANSFoRm project seeks to facilitate research using linked data from more than one source. We performed a requirements analysis which identified a wide range of data and business process requirements that need to be met before linking primary care and either genetic or disease registry data.Objectives To develop a survey to assess the readiness of data repositories to participate in linked research – the Transform International Research Readiness (TIRRE survey.Method We develop the questionnaire based on our requirement analysis; with questions at micro-, meso- and macro levels of granularity, study-specific questions about diabetes and gastro-oesophageal reflux disease (GORD, and research track record. The scope of the data required was extensive. We piloted this instrument, conducting ten preliminary telephone interviews to evaluate the response to the questionnaire.Results Using feedback gained from these interviews we revised the questionnaire; clarifying questions that were difficult to answer and utilising skip logic to create different series of questions for the various types of data repository. We simplified the questionnaire replacing free-text responses with yes/no or picking list options, wherever possible. We placed the final questionnaire online and encouraged its use (www.clininf.eu/jointirre/info.html.Conclusion Limited field testing suggests that TIRRE is capable of collecting comprehensive and relevant data about the suitability and readiness of data repositories to participate in linked data research.

Transformational leadership, adaptability, and job crafting : the moderating role of organizational identification.

NARCIS (Netherlands)

Wang, H.; Demerouti, E.; Le Blanc, P.M.

In this study, we aim to explore the link between transformational leadership and job crafting. We predict that transformational leadership will stimulate employee job crafting (seeking resources, seeking challenges, and reducing demands) by increasing their adaptability; but that transformational

Synchrosqueezing-based Transform and its Application in Seismic Data Analysis

Directory of Open Access Journals (Sweden)

Saman Gholtashi

2015-10-01

Full Text Available Seismic waves are non-stationary due to its propagation through the earth. Time-frequency transforms are suitable tools for analyzing non-stationary seismic signals. Spectral decomposition can reveal the non-stationary characteristics which cannot be easily observed in the time or frequency representation alone. Various types of spectral decomposition methods have been introduced by some researchers. Conventional spectral decompositions have some restrictions such as Heisenberg uncertainty principle and cross-terms which limit their applications in signal analysis. In this paper, synchrosqueezingbased transforms were used to overcome the mentioned restrictions; also, as an application of this new high resolution time-frequency analysis method, it was applied to random noise removal and the detection of low-frequency shadows in seismic data. The efficiency of this method is evaluated by applying it to both synthetic and real seismic data. The results show that the mentioned transform is a proper tool for seismic data processing and interpretation.

Transformation of mouse embryo (C3H 10T1/2) cells by alpha particles

International Nuclear Information System (INIS)

Lloyd, E.L.; Gemmell, A.; Henning, C.B.; Gemmell, D.S.; Zabransky, B.J.

1977-01-01

Mammalian cells in culture (C3H mouse 10T1/2 cells) have been shown here for the first time to be transformed by alpha irradiation when cells were irradiated with 5.6 MeV alpha particles from a Tandem Van de Graaff machine. Malignant tumors were induced following inoculation of the transformed cells into syngeneic hosts. Unirradiated control cells injected at the same concentration have, so far, failed to produce tumors. The morphology of the transformed foci was remarkably similar to that obtained by x rays and chemicals but different from virally transformed cells. When the cells were seeded at low density in the exponential growth phase, the transformation frequency per surviving cell increased approximately as the cube of the dose and peaked at an alpha particle fluence between 1.5 and 2.5 x 10 7 alpha particles per cm 2 (205 to 342 rads). The frequency of the transformation was found to be greatly dependent on the number of cells per dish irradiated. Irradiation of larger numbers resulted in much lower frequencies of transformation. The maximum transformation frequency observed in nine separate experiments was 4 percent of the surviving cells. At doses greater than 200 rads the transformation frequency per surviving cell remained constant. The present results permit us to conclude that alpha irradiation may, indeed, be able to exert a direct effect on the genome of the cell to produce malignancy without any external immunological or hormonal influences

Electrical properties of a piezoelectric transformer for an AC-DC converter

International Nuclear Information System (INIS)

Park, Yong-Wook

2010-01-01

The electrical properties of a ring/dot piezoelectric transformer were analyzed for applications as an AC-DC converter using the step-down behavior of a piezoelectric transformer. The ring/dot piezoelectric transformer was prepared using Pb(Mn 1/3 Nb 2/3 )O 3 and Pb(Zn 1/3 Nb 2/3 )O 3 modified Pb(Zr,Ti)O 3 ceramics sintered at a relatively low temperature of 930 .deg. C for 90 min. When the transformer was matched with a load resistance of 1000 Ω, it transferred a maximum power of 27 W. The maximum power was produced at a dc output voltage of 30 V and a matching load resistance of 1000 Ω. While the manufactured ring/dot piezoelectric transformer released the maximum power at a resonance frequency of 71 kHz, the available frequency bandwidth was about 1 kHz at most due to strong frequency dependence of the piezoelectric transformer. The output dc current was highly improved up to 905 mA because no anisotropy of poling direction existed in the ring/dot piezoelectric transformer. Under a commercial input of 220 V ac , AC-DC converter successfully produced 27 W at 30 V dc and 905 mA.

The PROSAIC Laplace and Fourier Transform

International Nuclear Information System (INIS)

Smith, G.A.

1994-01-01

Integral Transform methods play an extremely important role in many branches of science and engineering. The ease with which many problems may be solved using these techniques is well known. In Electrical Engineering especially, Laplace and Fourier Transforms have been used for a long time as a way to change the solution of differential equations into trivial algebraic manipulations or to provide alternate representations of signals and data. These techniques, while seemingly overshadowed by today's emphasis on digital analysis, still form an invaluable basis in the understanding of systems and circuits. A firm grasp of the practical aspects of these subjects provides valuable conceptual tools. This tutorial paper is a review of Laplace and Fourier Transforms from an applied perspective with an emphasis on engineering applications. The interrelationship of the time and frequency domains will be stressed, in an attempt to comfort those who, after living so much of their lives in the time domain, find thinking in the frequency domain disquieting

Induced over voltage test on transformers using enhanced Z-source inverter based circuit

Science.gov (United States)

Peter, Geno; Sherine, Anli

2017-09-01

The normal life of a transformer is well above 25 years. The economical operation of the distribution system has its roots in the equipments being used. The economy being such, that it is financially advantageous to replace transformers with more than 15 years of service in the second perennial market. Testing of transformer is required, as its an indication of the extent to which a transformer can comply with the customers specified requirements and the respective standards (IEC 60076-3). In this paper, induced over voltage testing on transformers using enhanced Z source inverter is discussed. Power electronic circuits are now essential for a whole array of industrial electronic products. The bulky motor generator set, which is used to generate the required frequency to conduct the induced over voltage testing of transformers is nowadays replaced by static frequency converter. First conventional Z-source inverter, and second an enhanced Z source inverter is being used to generate the required voltage and frequency to test the transformer for induced over voltage test, and its characteristics is analysed.

An Epstein-Barr virus anti-apoptotic protein constitutively expressed in transformed cells and implicated in burkitt lymphomagenesis: the Wp/BHRF1 link.

Directory of Open Access Journals (Sweden)

Gemma L Kelly

2009-03-01

Full Text Available Two factors contribute to Burkitt lymphoma (BL pathogenesis, a chromosomal translocation leading to c-myc oncogene deregulation and infection with Epstein-Barr virus (EBV. Although the virus has B cell growth-transforming ability, this may not relate to its role in BL since many of the transforming proteins are not expressed in the tumor. Mounting evidence supports an alternative role, whereby EBV counteracts the high apoptotic sensitivity inherent to the c-myc-driven growth program. In that regard, a subset of BLs carry virus mutants in a novel form of latent infection that provides unusually strong resistance to apoptosis. Uniquely, these virus mutants use Wp (a viral promoter normally activated early in B cell transformation and express a broader-than-usual range of latent antigens. Here, using an inducible system to express the candidate antigens, we show that this marked apoptosis resistance is mediated not by one of the extended range of EBNAs seen in Wp-restricted latency but by Wp-driven expression of the viral bcl2 homologue, BHRF1, a protein usually associated with the virus lytic cycle. Interestingly, this Wp/BHRF1 connection is not confined to Wp-restricted BLs but appears integral to normal B cell transformation by EBV. We find that the BHRF1 gene expression recently reported in newly infected B cells is temporally linked to Wp activation and the presence of W/BHRF1-spliced transcripts. Furthermore, just as Wp activity is never completely eclipsed in in vitro-transformed lines, low-level BHRF1 transcripts remain detectable in these cells long-term. Most importantly, recognition by BHRF1-specific T cells confirms that such lines continue to express the protein independently of any lytic cycle entry. This work therefore provides the first evidence that BHRF1, the EBV bcl2 homologue, is constitutively expressed as a latent protein in growth-transformed cells in vitro and, in the context of Wp-restricted BL, may contribute to virus

Hough transform search for continuous gravitational waves

International Nuclear Information System (INIS)

Krishnan, Badri; Papa, Maria Alessandra; Sintes, Alicia M.; Schutz, Bernard F.; Frasca, Sergio; Palomba, Cristiano

2004-01-01

This paper describes an incoherent method to search for continuous gravitational waves based on the Hough transform, a well-known technique used for detecting patterns in digital images. We apply the Hough transform to detect patterns in the time-frequency plane of the data produced by an earth-based gravitational wave detector. Two different flavors of searches will be considered, depending on the type of input to the Hough transform: either Fourier transforms of the detector data or the output of a coherent matched-filtering type search. We present the technical details for implementing the Hough transform algorithm for both kinds of searches, their statistical properties, and their sensitivities

The fractional Fourier transform and applications

Science.gov (United States)

Bailey, David H.; Swarztrauber, Paul N.

1991-01-01

This paper describes the 'fractional Fourier transform', which admits computation by an algorithm that has complexity proportional to the fast Fourier transform algorithm. Whereas the discrete Fourier transform (DFT) is based on integral roots of unity e exp -2(pi)i/n, the fractional Fourier transform is based on fractional roots of unity e exp -2(pi)i(alpha), where alpha is arbitrary. The fractional Fourier transform and the corresponding fast algorithm are useful for such applications as computing DFTs of sequences with prime lengths, computing DFTs of sparse sequences, analyzing sequences with noninteger periodicities, performing high-resolution trigonometric interpolation, detecting lines in noisy images, and detecting signals with linearly drifting frequencies. In many cases, the resulting algorithms are faster by arbitrarily large factors than conventional techniques.

Query transformations and their role in Web searching by the members of the general public

Directory of Open Access Journals (Sweden)

Martin Whittle

2006-01-01

Full Text Available Introduction. This paper reports preliminary research in a primarily experimental study of how the general public search for information on the Web. The focus is on the query transformation patterns that characterise searching. Method. In this work, we have used transaction logs from the Excite search engine to develop methods for analysing query transformations that should aid the analysis of our ongoing experimental work. Our methods involve the use of similarity techniques to link queries with the most similar previous query in a train. The resulting query transformations are represented as a list of codes representing a whole search. Analysis. It is shown how query transformation sequences can be represented as graphical networks and some basic statistical results are shown. A correlation analysis is performed to examine the co-occurrence of Boolean and quotation mark changes with the syntactic changes. Results. A frequency analysis of the occurrence of query transformation codes is presented. The connectivity of graphs obtained from the query transformation is investigated and found to follow an exponential scaling law. The correlation analysis reveals a number of patterns that provide some interesting insights into Web searching by the general public. Conclusion. We have developed analytical methods based on query similarity that can be applied to our current experimental work with volunteer subjects. The results of these will form part of a database with the aim of developing an improved understanding of how the public search the Web.

General n-dimensional quadrature transform and its application to interferogram demodulation.

Science.gov (United States)

Servin, Manuel; Quiroga, Juan Antonio; Marroquin, Jose Luis

2003-05-01

Quadrature operators are useful for obtaining the modulating phase phi in interferometry and temporal signals in electrical communications. In carrier-frequency interferometry and electrical communications, one uses the Hilbert transform to obtain the quadrature of the signal. In these cases the Hilbert transform gives the desired quadrature because the modulating phase is monotonically increasing. We propose an n-dimensional quadrature operator that transforms cos(phi) into -sin(phi) regardless of the frequency spectrum of the signal. With the quadrature of the phase-modulated signal, one can easily calculate the value of phi over all the domain of interest. Our quadrature operator is composed of two n-dimensional vector fields: One is related to the gradient of the image normalized with respect to local frequency magnitude, and the other is related to the sign of the local frequency of the signal. The inner product of these two vector fields gives us the desired quadrature signal. This quadrature operator is derived in the image space by use of differential vector calculus and in the frequency domain by use of a n-dimensional generalization of the Hilbert transform. A robust numerical algorithm is given to find the modulating phase of two-dimensional single-image closed-fringe interferograms by use of the ideas put forward.

Power Quality Problems Due to Transformer Inrush Current

OpenAIRE

Tokić, A.; Uglešić, I.

2017-01-01

Transformer energization can produce a large nonsinuoidal inrush current which contains both odd and higher order harmonic components that can put transformer winding under mechanical stress. Additionally, they can cause irregular tripping of harmonic protection relays. Furthermore, in relatively weak power systems, such as is the Bosnian system, the superposition of harmonic components with system resonance frequencies may produce temporary overvoltages (TOV). Transformer wind...

A two-dimensional time domain near zone to far zone transformation

Science.gov (United States)

Luebbers, Raymond J.; Ryan, Deirdre; Beggs, John H.; Kunz, Karl S.

1991-01-01

In a previous paper, a time domain transformation useful for extrapolating 3-D near zone finite difference time domain (FDTD) results to the far zone was presented. In this paper, the corresponding 2-D transform is outlined. While the 3-D transformation produced a physically observable far zone time domain field, this is not convenient to do directly in 2-D, since a convolution would be required. However, a representative 2-D far zone time domain result can be obtained directly. This result can then be transformed to the frequency domain using a Fast Fourier Transform, corrected with a simple multiplicative factor, and used, for example, to calculate the complex wideband scattering width of a target. If an actual time domain far zone result is required it can be obtained by inverse Fourier transform of the final frequency domain result.

Education as Habitus Transformations

Science.gov (United States)

von Rosenberg, Florian

2016-01-01

Unlike a conventional reading of Bourdieu, this article focuses on his work with regard to the transformation of social structure. In the context of a rereading, from an educational theory perspective, the article proposes an approach that allows for the linking of empirically informed social theory, on the one hand, and biography research…

Electromechanical characteristics of piezoelectric ceramic transformers in radial vibration composed of concentric piezoelectric ceramic disk and ring

International Nuclear Information System (INIS)

Lin, Shuyu; Hu, Jing; Fu, Zhiqiang

2013-01-01

A new type of piezoelectric ceramic transformer in radial vibration is presented. The piezoelectric transformer consists of a pairing of a concentric piezoelectric ceramic circular disk and ring. The inner piezoelectric ceramic disk is axially polarized and the outer piezoelectric ring is radially polarized. Based on the plane stress theory, the exact analytical theory for the piezoelectric transformer is developed and its electromechanical equivalent circuit is introduced. The resonance/anti-resonance frequency equations of the transformer are obtained and the relationship between the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient and the geometrical dimensions of the piezoelectric transformer is analyzed. The dependency of the voltage transformation ratio on the frequency is obtained. To verify the analytical theory, a numerical method is used to simulate the electromechanical characteristics of the piezoelectric transformer. It is shown that the analytical resonance/anti-resonance frequencies are in good agreement with the numerical results. (paper)

Inferring river bathymetry via Image-to-Depth Quantile Transformation (IDQT)

Science.gov (United States)

Legleiter, Carl

2016-01-01

Conventional, regression-based methods of inferring depth from passive optical image data undermine the advantages of remote sensing for characterizing river systems. This study introduces and evaluates a more flexible framework, Image-to-Depth Quantile Transformation (IDQT), that involves linking the frequency distribution of pixel values to that of depth. In addition, a new image processing workflow involving deep water correction and Minimum Noise Fraction (MNF) transformation can reduce a hyperspectral data set to a single variable related to depth and thus suitable for input to IDQT. Applied to a gravel bed river, IDQT avoided negative depth estimates along channel margins and underpredictions of pool depth. Depth retrieval accuracy (R25 0.79) and precision (0.27 m) were comparable to an established band ratio-based method, although a small shallow bias (0.04 m) was observed. Several ways of specifying distributions of pixel values and depths were evaluated but had negligible impact on the resulting depth estimates, implying that IDQT was robust to these implementation details. In essence, IDQT uses frequency distributions of pixel values and depths to achieve an aspatial calibration; the image itself provides information on the spatial distribution of depths. The approach thus reduces sensitivity to misalignment between field and image data sets and allows greater flexibility in the timing of field data collection relative to image acquisition, a significant advantage in dynamic channels. IDQT also creates new possibilities for depth retrieval in the absence of field data if a model could be used to predict the distribution of depths within a reach.

Properties of the Simpson discrete fourier transform | Singh ...

African Journals Online (AJOL)

The Simpson discrete Fourier transform (SDFT) and its inverse are transformations relating the time and frequency domains. In this paper we state and prove the important properties of shift, circular convolution, conjugation, time reversal and Plancherel's theorem. In addition, we provide an alternative representation of the ...

Automatic traveltime picking using local time-frequency maps

KAUST Repository

Saragiotis, Christos; Alkhalifah, Tariq Ali; Fomel, Sergey B.

2011-01-01

The arrival times of distinct and sufficiently concentrated signals can be computed using Fourier transforms. In real seis- mograms, however, signals are far from distinct. We use local time-frequency maps of the seismograms and its frequency

Applications of wavelet transforms for nuclear power plant signal analysis

International Nuclear Information System (INIS)

Seker, S.; Turkcan, E.; Upadhyaya, B.R.; Erbay, A.S.

1998-01-01

The safety of Nuclear Power Plants (NPPs) may be enhanced by the timely processing of information derived from multiple process signals from NPPs. The most widely used technique in signal analysis applications is the Fourier transform in the frequency domain to generate power spectral densities (PSD). However, the Fourier transform is global in nature and will obscure any non-stationary signal feature. Lately, a powerful technique called the Wavelet Transform, has been developed. This transform uses certain basis functions for representing the data in an effective manner, with capability for sub-band analysis and providing time-frequency localization as needed. This paper presents a brief overview of wavelets applied to the nuclear industry for signal processing and plant monitoring. The basic theory of Wavelets is also summarized. In order to illustrate the application of wavelet transforms data were acquired from the operating nuclear power plant Borssele in the Netherlands. The experimental data consist of various signals in the power plant and are selected from a stationary power operation. Their frequency characteristics and the mutual relations were investigated using MATLAB signal processing and wavelet toolbox for computing their PSDs and coherence functions by multi-resolution analysis. The results indicate that the sub-band PSD matches with the original signal PSD and enhances the estimation of coherence functions. The Wavelet analysis demonstrates the feasibility of application to stationary signals to provide better estimates in the frequency band of interest as compared to the classical FFT approach. (author)

Non-stationary component extraction in noisy multicomponent signal using polynomial chirping Fourier transform.

Science.gov (United States)

Lu, Wenlong; Xie, Junwei; Wang, Heming; Sheng, Chuan

2016-01-01

Inspired by track-before-detection technology in radar, a novel time-frequency transform, namely polynomial chirping Fourier transform (PCFT), is exploited to extract components from noisy multicomponent signal. The PCFT combines advantages of Fourier transform and polynomial chirplet transform to accumulate component energy along a polynomial chirping curve in the time-frequency plane. The particle swarm optimization algorithm is employed to search optimal polynomial parameters with which the PCFT will achieve a most concentrated energy ridge in the time-frequency plane for the target component. The component can be well separated in the polynomial chirping Fourier domain with a narrow-band filter and then reconstructed by inverse PCFT. Furthermore, an iterative procedure, involving parameter estimation, PCFT, filtering and recovery, is introduced to extract components from a noisy multicomponent signal successively. The Simulations and experiments show that the proposed method has better performance in component extraction from noisy multicomponent signal as well as provides more time-frequency details about the analyzed signal than conventional methods.

How transformational leadership works during team interactions: A behavioral process analysis

OpenAIRE

Lehmann-Willenbrock, N.K.; Meinecke, A.L.; Rowold, J.; Kauffeld, S.

2015-01-01

Transformational leadership is generally considered helpful for team functioning. However, the social dynamics underlying the benefits of transformational leadership remain elusive to date. To understand how and why transformational leadership can foster team functioning, this study focuses on leader-follower communication dynamics during team interactions. From the perspective of leadership as social problem solving, we argue that transformational leadership is linked to functional team prob...

Efficient 3D frequency response modeling with spectral accuracy by the rapid expansion method

KAUST Repository

Chu, Chunlei; Stoffa, Paul L.

2012-01-01

Frequency responses of seismic wave propagation can be obtained either by directly solving the frequency domain wave equations or by transforming the time domain wavefields using the Fourier transform. The former approach requires solving systems

Overload Control in Smart Transformer-Fed Grid

Directory of Open Access Journals (Sweden)

Giovanni De Carne

2017-02-01

Full Text Available Renewable energy resources and new loads—such as electric vehicles—challenge grid management. Among several scenarios, the smart transformer represents a solution for simultaneously managing low- and medium-voltage grids, providing ancillary services to the distribution grid. However, unlike conventional transformers, the smart transformer has a very limited overload capability, because the junction temperature—which must always be below its maximum limit—is characterized by a short time constant. In this work, an overload control for smart transformer by means of voltage and frequency variations has been proposed and verified by means of simulations and experiments.

Warm Arctic episodes linked with increased frequency of extreme winter weather in the United States.

Science.gov (United States)

Cohen, Judah; Pfeiffer, Karl; Francis, Jennifer A

2018-03-13

Recent boreal winters have exhibited a large-scale seesaw temperature pattern characterized by an unusually warm Arctic and cold continents. Whether there is any physical link between Arctic variability and Northern Hemisphere (NH) extreme weather is an active area of research. Using a recently developed index of severe winter weather, we show that the occurrence of severe winter weather in the United States is significantly related to anomalies in pan-Arctic geopotential heights and temperatures. As the Arctic transitions from a relatively cold state to a warmer one, the frequency of severe winter weather in mid-latitudes increases through the transition. However, this relationship is strongest in the eastern US and mixed to even opposite along the western US. We also show that during mid-winter to late-winter of recent decades, when the Arctic warming trend is greatest and extends into the upper troposphere and lower stratosphere, severe winter weather-including both cold spells and heavy snows-became more frequent in the eastern United States.

Quaternion Linear Canonical Transform Application

OpenAIRE

Bahri, Mawardi

2015-01-01

Quaternion linear canonical transform (QLCT) is a generalization of the classical linear canonical transfom (LCT) using quaternion algebra. The focus of this paper is to introduce an application of the QLCT to study of generalized swept-frequency filter

The Application of Time-Frequency Methods to HUMS

Science.gov (United States)

Pryor, Anna H.; Mosher, Marianne; Lewicki, David G.; Norvig, Peter (Technical Monitor)

2001-01-01

This paper reports the study of four time-frequency transforms applied to vibration signals and presents a new metric for comparing them for fault detection. The four methods to be described and compared are the Short Time Frequency Transform (STFT), the Choi-Williams Distribution (WV-CW), the Continuous Wavelet Transform (CWT) and the Discrete Wavelet Transform (DWT). Vibration data of bevel gear tooth fatigue cracks, under a variety of operating load levels, are analyzed using these methods. The new metric for automatic fault detection is developed and can be produced from any systematic numerical representation of the vibration signals. This new metric reveals indications of gear damage with all of the methods on this data set. Analysis with the CWT detects mechanical problems with the test rig not found with the other transforms. The WV-CW and CWT use considerably more resources than the STFT and the DWT. More testing of the new metric is needed to determine its value for automatic fault detection and to develop methods of setting the threshold for the metric.

All SiC Grid-Connected PV Supply with HF Link MPPT Converter: System Design Methodology and Development of a 20 kHz, 25 kVA Prototype

Directory of Open Access Journals (Sweden)

Serkan Öztürk

2018-05-01

Full Text Available Design methodology and implementation of an all SiC power semiconductor-based, grid-connected multi-string photovoltaic (PV supply with an isolated high frequency (HF link maximum power point tracker (MPPT have been described. This system configuration makes possible the use of a simple and reliable two-level voltage source inverter (VSI topology for grid connection, owing to the galvanic isolation provided by the HF transformer. This topology provides a viable alternative to the commonly used non-isolated PV supplies equipped with Si-based boost MPPT converters cascaded with relatively more complex inverter topologies, at competitive efficiency figures and a higher power density. A 20 kHz, 25 kVA prototype system was designed based on the dynamic model of the multi-string PV panels obtained from field tests. Design parameters such as input DC link capacitance, switching frequencies of MPPT converter and voltage source inverter, size and performance of HF transformer with nanocrystalline core, DC link voltage, and LCL filter of the VSI were optimized in view of the site dependent parameters such as the variation ranges of solar insolation, module surface temperature, and grid voltage. A modified synchronous reference frame control was implemented in the VSI by applying the grid voltage feedforward to the reference voltages in abc axes directly, so that zero-sequence components of grid voltages are taken into account in the case of an unbalanced grid. The system was implemented and the proposed design methodology verified satisfactorily in the field on a roof-mounted 23.7 kW multi-string PV system.

Digitally compensated beam current transformer

International Nuclear Information System (INIS)

Kesselman, Martin

2005-01-01

The Spallation Neutron Source (SNS) is being built by a collaboration of six laboratories. Beam current monitors (BCMs) will be used to record the current of H-minus and H-plus beams ranging from 15 mA (tune-up in the Front End and Linac) to over 60A fully accumulated in the Ring and dumped to the load as a single pulse in the Ring to Beam Target (RTBT). The time structure of these beams ranges from 645 ns 'mini' bunches at the 1.05 MHz ring revolution rate, to an overall 1 ms long macro-pulse. The requirements for the BCMs will depend upon their location within the system. The need to measure individual mini-pulses, examine the characteristics of the chopper edge, as well as the longer average current pulse of the macropulse, or long duration pulses during Linac tuning place wide requirements upon the response of current transformers. To obtain the desired accuracy and resolution, current transformers must have <1 ns rise time and droops of 0.1%/ms. This places a significant design burden on the current transformer; such a design is almost impossible to achieve. Extremely large expensive cores are needed to meet the low droop, while leakage inductance increases with size, thereby reducing the achievable rise time. In this paper, I discuss a digital compensation approach [M. Kesselman, Spallation neutron source beam current monitor electronics, PAC2001 June 18-22, 2001, Chicago, IL.] that extends the lower cut-off frequency of the current transformer, optimized for high frequency response, so that it can be used in this application with improvements in droop of the order of 1000:1. Transformer saturation (current-time product) is a separate issue and the transformer must be designed to handle the current-time product of the signal to assure it does not saturate

Dispersive Wave Analysis Using the Chirplet Transform

International Nuclear Information System (INIS)

Kerber, Florian; Luangvilai, Kritsakorn; Kuttig, Helge; Niethammer, Marc; Jacobs, Laurence J.

2007-01-01

Time-frequency representations (TFR) are a widely used tool to analyze signals of guided waves such as Lamb waves. As a consequence of the uncertainty principle, however, the resolution in time and frequency is limited for all existing TFR methods. Due to the multi-modal and dispersive character of Lamb waves, displacement or energy related quantities can only be allocated to individual modes when they are well-separated in the time-frequency plane.The chirplet transform (CT) has been introduced as a generalization of both the wavelet and Short-time Fourier transform (STFT). It offers additional degrees of freedom to adjust time-frequency atoms which can be exploited in a model-based approach to match the group delay of individual modes. Thus, more exact allocation of quantities of interest is possible.The objective of this research is to use a previously developed adaptive algorithm based on the CT for nondestructive evaluation. Both numerically and experimentally generated data for a single aluminum plate is analyzed to determine the accuracy and robustness of the new method in comparison the classical STFT

Iterative-Transform Phase Retrieval Using Adaptive Diversity

Science.gov (United States)

Dean, Bruce H.

2007-01-01

A phase-diverse iterative-transform phase-retrieval algorithm enables high spatial-frequency, high-dynamic-range, image-based wavefront sensing. [The terms phase-diverse, phase retrieval, image-based, and wavefront sensing are defined in the first of the two immediately preceding articles, Broadband Phase Retrieval for Image-Based Wavefront Sensing (GSC-14899-1).] As described below, no prior phase-retrieval algorithm has offered both high dynamic range and the capability to recover high spatial-frequency components. Each of the previously developed image-based phase-retrieval techniques can be classified into one of two categories: iterative transform or parametric. Among the modifications of the original iterative-transform approach has been the introduction of a defocus diversity function (also defined in the cited companion article). Modifications of the original parametric approach have included minimizing alternative objective functions as well as implementing a variety of nonlinear optimization methods. The iterative-transform approach offers the advantage of ability to recover low, middle, and high spatial frequencies, but has disadvantage of having a limited dynamic range to one wavelength or less. In contrast, parametric phase retrieval offers the advantage of high dynamic range, but is poorly suited for recovering higher spatial frequency aberrations. The present phase-diverse iterative transform phase-retrieval algorithm offers both the high-spatial-frequency capability of the iterative-transform approach and the high dynamic range of parametric phase-recovery techniques. In implementation, this is a focus-diverse iterative-transform phaseretrieval algorithm that incorporates an adaptive diversity function, which makes it possible to avoid phase unwrapping while preserving high-spatial-frequency recovery. The algorithm includes an inner and an outer loop (see figure). An initial estimate of phase is used to start the algorithm on the inner loop, wherein

On reciprocal Baecklund transformations of inverse scattering schemes

International Nuclear Information System (INIS)

Rogers, C.; Wong, P.

1984-01-01

The notion of reciprocally related inverse scattering schemes is introduced and is shown to be a key component in the link between the AKNS and WKI schemes. Reciprocal auto-Baecklund transformations are represented both for a generalised Harry-Dym equation and an equation descriptive of nonlinear oscillation of elastic beams. Further, the N-loop soliton solution of the KIW equation is generated in a convenient parametric form via reciprocal Baecklund transformations. Finally, an important reduction to canonical spectral form is shown to be a reciprocal transformation. (Auth.)

Analysis on Behaviour of Wavelet Coefficient during Fault Occurrence in Transformer

Science.gov (United States)

Sreewirote, Bancha; Ngaopitakkul, Atthapol

2018-03-01

The protection system for transformer has play significant role in avoiding severe damage to equipment when disturbance occur and ensure overall system reliability. One of the methodology that widely used in protection scheme and algorithm is discrete wavelet transform. However, characteristic of coefficient under fault condition must be analyzed to ensure its effectiveness. So, this paper proposed study and analysis on wavelet coefficient characteristic when fault occur in transformer in both high- and low-frequency component from discrete wavelet transform. The effect of internal and external fault on wavelet coefficient of both fault and normal phase has been taken into consideration. The fault signal has been simulate using transmission connected to transformer experimental setup on laboratory level that modelled after actual system. The result in term of wavelet coefficient shown a clearly differentiate between wavelet characteristic in both high and low frequency component that can be used to further design and improve detection and classification algorithm that based on discrete wavelet transform methodology in the future.

The prosaic Laplace and Fourier transform

International Nuclear Information System (INIS)

Smith, G.A.

1995-01-01

Integral Transform methods play an extremely important role in many branches of science and engineering. The ease with which many problems may be solved using these techniques is well known. In Electrical Engineering especially, Laplace and Fourier Transforms have been used for a long time as a way to change the solution of differential equations into trivial algebraic manipulations or to provide alternate representations of signals and data. These techniques, while seemingly overshadowed by today's emphasis on digital analysis, still form an invaluable basis in the understanding of systems and circuits. A firm grasp of the practical aspects of these subjects provides valuable conceptual tools. This tutorial paper is a review of Laplace and Fourier Transforms from an applied perspective with an emphasis on engineering applications. The interrelationship of the time and frequency domains will be stressed, in an attempt to comfort those who, after living so much of their lives in the time domain, find thinking in the frequency domain disquieting. copyright 1995 American Institute of Physics

Analysis of Ultrasonic Transmitted Signal for Apple using Wavelet Transform

International Nuclear Information System (INIS)

Kim, Ki Bok; Lee, Sang Dae; Choi, Man Yong; Kim, Man Soo

2005-01-01

This study was conducted to analyze the ultrasonic transmitted signal for apple using wavelet transform. Fruit consists of nonlinear visco-elastic properties such as flesh, an ovary and rind and lienee most ultrasonic wave is attenuated and its frequency is shifted during passing the fruit. Thus it is not easy to evaluate the internal quality of the fruit using typical ultrasonic parameters such as wave velocity, attenuation, and frequency spectrum. The discrete wavelet transform was applied to the ultrasonic transmitted signal for apple. The magnitude of the first peak frequency of the wavelet basis from the ultrasonic transmitted signal showed a close correlation to the storage time of apple

Derivation of Oscillators from Biquadratic Band Pass Filters Using Circuit Transformations

Directory of Open Access Journals (Sweden)

Hung-Yu Wang

2014-09-01

Full Text Available Network transformations are the techniques to obtain new functional schemes from available circuits. They are systematic methodologies, since each transformation technique can be applied to many circuits to obtain the desired functions or characteristics. A convenient network transformation method, exploiting different circuit transformations, for deriving linear sinusoidal oscillators from biquadratic band pass filters is proposed. This method with generality can be applied to any band pass filter. The oscillation frequency of the new obtained oscillator is identical to the center frequency of the original band pass filter, and the useful properties of the selected band pass filter can be retained. Two examples are illustrated to confirm the feasibility of the proposed approach. The workability of the obtained oscillators is verified with PSPICE simulations.

Magnetic field measurements near stand-alone transformer stations.

Science.gov (United States)

Kandel, Shaiela; Hareuveny, Ronen; Yitzhak, Nir-Mordechay; Ruppin, Raphael

2013-12-01

Extremely low-frequency (ELF) magnetic field (MF) measurements around and above three stand-alone 22/0.4-kV transformer stations have been performed. The low-voltage (LV) cables between the transformer and the LV switchgear were found to be the major source of strong ELF MFs of limited spatial extent. The strong fields measured above the transformer stations support the assessment method, to be used in future epidemiological studies, of classifying apartments located right above the transformer stations as highly exposed to MFs. The results of the MF measurements above the ground around the transformer stations provide a basis for the assessment of the option of implementing precautionary procedures.

Ground Radar Polarimetric Observations of High-Frequency Earth-Space Communication Links

Science.gov (United States)

Bolen, Steve; Chandrasekar, V.; Benjamin, Andrew

2002-01-01

Strategic roadmaps for NASA's Human Exploration and Development of Space (REDS) enterprise support near-term high-frequency communication systems that provide moderate to high data rates with dependable service. Near-earth and human planetary exploration will baseline Ka-Band, but may ultimately require the use of even higher frequencies. Increased commercial demand on low-frequency earth-space bands has also led to increased interest in the use of higher frequencies in regions like K u - and K,- band. Data is taken from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), which operates at 13.8 GHz, and the true radar reflectivity profile is determined along the PR beam via low-frequency ground based polarimetric observations. The specific differential phase (Kdp) is measured along the beam and a theoretical model is used to determine the expected specific attenuation (k). This technique, called the k-Kdp method, uses a Fuzzy-Logic model to determine the hydrometeor type along the PR beam from which the appropriate k-Kdp relationship is used to determine k and, ultimately, the total path-integrated attenuation (PIA) on PR measurements. Measurements from PR and the NCAR S-POL radar were made during the TEFLUN-B experiment that took place near Melbourne, FL in 1998, and the TRMM-LBA campaign near Ji-Parana, Brazil in 1999.

Some Notes on the Use of theWindowed Fourier Transform for Spectral Analysis of Discretely Sampled Data

Directory of Open Access Journals (Sweden)

Robert W. Johnson

2013-06-01

Full Text Available The properties of the Gabor and Morlet transforms are examined with respect to the Fourier analysis of discretely sampled data. Forward and inverse transform pairs based on a fixed window with uniform sampling of the frequency axis can satisfy numerically the energy and reconstruction theorems; however, transform pairs based on a variable window or nonuniform frequency sampling in general do not. Instead of selecting the shape of the window as some function of the central frequency, we propose constructing a single window with unit energy from an arbitrary set of windows that is applied over the entire frequency axis. By virtue of using a fixed window with uniform frequency sampling, such a transform satisfies the energy and reconstruction theorems. The shape of the window can be tailored to meet the requirements of the investigator in terms of time/frequency resolution. The algorithm extends naturally to the case of nonuniform signal sampling without modification beyond identification of the Nyquist interval.

LINKING PERSONAL COMPETENCIES WITH TRANSFORMATIONAL LEADERSHIP STYLE EVIDENCE FROM THE CONSTRUCTION INDUSTRY IN THAILAND

Directory of Open Access Journals (Sweden)

Kedsuda Limsila

2008-06-01

Full Text Available This study explored the linkage between personal competencies and leadership behaviours as well as their influences on leadership outcomes and subordinates’ work performance. Personal competencies were measured using the Project Manager Competency Development (PMCD tool. Leadership behaviours and outcomes were measured using Multifactor Leadership Questionnaire (MLQ. Data was collected from construction projects in Thailand. Findings revealed that leadership outcomes have significant positive relationship with all personal competencies specified in the PMCD framework, every factor in the transformational style and contingent reward factor in the transactional style. Transformational leaders tend to produce high work quality, work quantity, and problem solving creativity from subordinates. Findings further verified that all PMCD personal competencies have significant positive relationship with every factor in the transformational style. It implies that project managers who apply the transformational style and/or have high personal competencies indicated in PMCD framework are likely to generate greater leadership outcomes and work performance on construction projects.

Transformer Impedance Reflection Demonstration

Science.gov (United States)

Layton, William

2014-01-01

Questions often arise as to how a device attached to a transformer can draw power from the electrical power grid since it seems that the primary and secondary are not connected to one another. However, a closer look at how the primary and secondary are linked together magnetically and a consideration of the role of Lenz's law in this linkage…

Learning by Example: Designing and Developing Linked Data Application

Science.gov (United States)

Tharani, Karim

2016-01-01

According to constructivist theory of learning, new knowledge is learned on the basis of what is already known by learners. Thus for an emerging and transformative technology such as Linked Data to be learned, the technology must be made relevant for learners and must be compatible with their skillset. Designing and developing Linked Data…

Visualising the Process of Transformation

DEFF Research Database (Denmark)

Pedersen, Pia

2012-01-01

This paper investigates the process of transformation that is part of the ISOTYPE (International System Of TYpographic Picture Education) system, using the correspondence between Austrian sociologist Otto Neurath /his wife Marie Neurath and Town Clerk A. V. Williams of the town of Bilston in the UK....... The letters were written around 1946 and are part of the preparations for creating an exhibition—containing 12 charts—on a possible housing development project in Bilston, a poor neighbourhood in Staffordshire, England. According to the ISOTYPE system, the transformer, the link between expert and artist (M....... Neurath, 1960: 113-115), works across disciplines on organizing, analysing and configuring data into visual form (Kinross, 2009:6). It is my intention to use the correspondence from this transformation process to build on earlier identification and visualisation of the essential principles...

Simulation of power fluctuation of wind farms based on frequency domain

DEFF Research Database (Denmark)

Lin, Jin; Sun, Yuanzhang; Li, Guojie

2011-01-01

The wind power fluctuation model built up in the frequency domain is mathematically equivalent with that in the time domain, and has a clearer physical meaning therefore describes the fluctuation more accurately. However, the simulation of this model is required to deal with the time......-frequency transformation related to the power spectrum density (PSD), which is more special and complicated than normal transformations. Meanwhile, the computational complexity also increases significantly, more computation resources are needed. These problems negatively affect the engineering application of the model....... To overcome these disadvantages, the physical meaning of PSD based on fundamental concepts is presented, so that the specialties of this model compared with conventional ones can be understood. Then the time-frequency transformation algorithm is derived, which is fast to be implemented in digital computers...

Highly-efficient liposome-mediated transformation system for the basidiomycetous fungus Flammulina velutipes.

Science.gov (United States)

Shi, Liang; Chen, Dongdong; Xu, Chao; Ren, Ang; Yu, Hanshou; Zhao, Mingwen

2017-07-11

Flammulina velutipes is a well-known edible mushroom cultivated all over the world. However, because of the low transformation frequency, the expensive instruments required, and the complicated, time-consuming procedures necessary, there is insufficient genetic research on F. velutipes. In this study, we report a liposome-mediated transformation (LMT) system for the genetic transformation of F. velutipes. Using the LMT system, we obtained 82 ± 4 stable F. velutipes transformants per 10 5 protoplasts, which is a clear increase in transformation frequency compared to the other methods used. We were able to detect the expression of an EGFP reporter gene in the F. velutipes transformants using fluorescence imaging assays. Furthermore, we used this method to transfer the laccase gene into F. velutipes and found that the transcriptional level and enzymatic activity increased in these transformants. Mitotic stability analysis showed that all of the selected transformants remained mitotically stable, even after five successive rounds of sub-culturing. These results demonstrate a new transgenic approach that will facilitate F. velutipes research.

Radiation-induced transformation in oncogene primed C3H/10T1/2 cells; a new system for analysis of multi-step transformation in vitro

International Nuclear Information System (INIS)

Drozdoff, V.V.

1988-01-01

Several established rodent cell lines, such as C3H/10T1/2 fibroblasts, have been developed to study radiation and chemically-induced malignant transformation. Most experimental evidence has supported the idea that transformation in 10T1/2 cells involved at least two steps but that the apparent frequency of transformation depends on the density of plated cells. A new approach is presented here for studying radiation-induced transformation. An oncogene primed cell system (C3H-myc) was developed by introducing a constitutively active mouse c-myc gene into 10T1/2 cells. A primary goal was to determine if the introduction of an activated oncogene could substitute for one of the required steps in radiation-induced transformation. Results are presented that show that the expression of the exogenous myc gene significantly increased the frequency of radiation-induced transformation in these cells. Subculture experiments performed to analyze the kinetics of transformation in C3H-myc cells and reconstruction experiments allowing the effects of normal cells on radiation-induced transformants to be determined indicated that transformed cells arose very shortly after irradiation. These results support the conclusion that a radiation-induced event can complement the effect of myc in C3H-myc cells and directly result in transformation. This system thus provides an opportunity to isolate early steps in radiation-induced transformation and should facilitate the identification and analysis of these events

Transforming network simulation data to semantic data for network attack planning

CSIR Research Space (South Africa)

Chan, Ke Fai Peter

2017-03-01

Full Text Available study was performed, using the Common Open Research Emulator (CORE), to generate the necessary network simulation data. The simulation data was analysed, and then transformed into linked data. The result of the transformation is a data file that adheres...

Vibration mode and vibration shape under excitation of a three phase model transformer core

Science.gov (United States)

Okabe, Seiji; Ishigaki, Yusuke; Omura, Takeshi

2018-04-01

Structural vibration characteristics and vibration shapes under three-phase excitation of a archetype transformer core were investigated to consider their influences on transformer noise. Acoustic noise and vibration behavior were measured in a three-limb model transformer core. Experimental modal analysis by impact test was performed. The vibration shapes were measured by a laser scanning vibrometer at different exciting frequencies. Vibration amplitude of the core in out-of-plane direction were relatively larger than those in other two in-plane directions. It was consistent with the result that the frequency response function of the core in out-of-plane direction was larger by about 20 dB or more than those in in-plane directions. There were many vibration modes having bending deformation of limbs in out-of-plane direction. The vibration shapes of the core when excited at 50 Hz and 60 Hz were almost the same because the fundamental frequencies of the vibration were not close to the resonance frequencies. When excitation frequency was 69 Hz which was half of one of the resonance frequencies, the vibration shape changed to the one similar to the resonance vibration mode. Existence of many vibration modes in out-of-plane direction of the core was presumed to be a reason why frequency characteristics of magnetostriction and transformer noise do not coincide.

Reciprocal link for a coupled Camassa–Holm type equation

International Nuclear Information System (INIS)

Li, Nianhua; Zhang, Jinshun; Wu, Lihua

2016-01-01

Highlights: • We construct a reciprocal transformation for a coupled Camassa–Holm type equation proposed by Geng and Xue. • The transformed coupled Camassa–Holm type system is a reduction of the first negative flow in a modified Drinfeld–Sokolov III hierarchy. • The Lax pair and bi-Hamiltonian structure behaviors of the coupled Camassa–Holm type equation under the reciprocal transformation are analyzed. - Abstract: A coupled Camassa–Holm type equation is linked to the first negative flow in a modified Drinfeld–Sokolov III hierarchy by a transformation of reciprocal type. Meanwhile the Lax pair and bi-Hamiltonian structure behaviors of this coupled Camassa–Holm type equation under the reciprocal transformation are analyzed.

Frequency Splitting Analysis and Compensation Method for Inductive Wireless Powering of Implantable Biosensors.

Science.gov (United States)

Schormans, Matthew; Valente, Virgilio; Demosthenous, Andreas

2016-08-04

Inductive powering for implanted medical devices, such as implantable biosensors, is a safe and effective technique that allows power to be delivered to implants wirelessly, avoiding the use of transcutaneous wires or implanted batteries. Wireless powering is very sensitive to a number of link parameters, including coil distance, alignment, shape, and load conditions. The optimum drive frequency of an inductive link varies depending on the coil spacing and load. This paper presents an optimum frequency tracking (OFT) method, in which an inductive power link is driven at a frequency that is maintained at an optimum value to ensure that the link is working at resonance, and the output voltage is maximised. The method is shown to provide significant improvements in maintained secondary voltage and system efficiency for a range of loads when the link is overcoupled. The OFT method does not require the use of variable capacitors or inductors. When tested at frequencies around a nominal frequency of 5 MHz, the OFT method provides up to a twofold efficiency improvement compared to a fixed frequency drive. The system can be readily interfaced with passive implants or implantable biosensors, and lends itself to interfacing with designs such as distributed implanted sensor networks, where each implant is operating at a different frequency.

Frequency Splitting Analysis and Compensation Method for Inductive Wireless Powering of Implantable Biosensors

Directory of Open Access Journals (Sweden)

Matthew Schormans

2016-08-01

Full Text Available Inductive powering for implanted medical devices, such as implantable biosensors, is a safe and effective technique that allows power to be delivered to implants wirelessly, avoiding the use of transcutaneous wires or implanted batteries. Wireless powering is very sensitive to a number of link parameters, including coil distance, alignment, shape, and load conditions. The optimum drive frequency of an inductive link varies depending on the coil spacing and load. This paper presents an optimum frequency tracking (OFT method, in which an inductive power link is driven at a frequency that is maintained at an optimum value to ensure that the link is working at resonance, and the output voltage is maximised. The method is shown to provide significant improvements in maintained secondary voltage and system efficiency for a range of loads when the link is overcoupled. The OFT method does not require the use of variable capacitors or inductors. When tested at frequencies around a nominal frequency of 5 MHz, the OFT method provides up to a twofold efficiency improvement compared to a fixed frequency drive. The system can be readily interfaced with passive implants or implantable biosensors, and lends itself to interfacing with designs such as distributed implanted sensor networks, where each implant is operating at a different frequency.

Modelling the pulse transformer in SPICE

International Nuclear Information System (INIS)

Godlewska, Malgorzata; Górecki, Krzysztof; Górski, Krzysztof

2016-01-01

The paper is devoted to modelling pulse transformers in SPICE. It shows the character of the selected models of this element, points out their advantages and disadvantages, and presents the results of experimental verification of the considered models. These models are characterized by varying degrees of complexity - from linearly coupled linear coils to nonlinear electrothermal models. The study was conducted for transformer with ring cores made of a variety of ferromagnetic materials, while exciting the sinusoidal signal of a frequency 100 kHz and different values of load resistance. The transformers operating conditions under which the considered models ensure the acceptable accuracy of calculations are indicated

T-DNA transfer and T-DNA integration efficiencies upon Arabidopsis thaliana root explant cocultivation and floral dip transformation.

Science.gov (United States)

Ghedira, Rim; De Buck, Sylvie; Van Ex, Frédéric; Angenon, Geert; Depicker, Ann

2013-12-01

T-DNA transfer and integration frequencies during Agrobacterium-mediated root explant cocultivation and floral dip transformations of Arabidopsis thaliana were analyzed with and without selection for transformation-competent cells. Based on the presence or absence of CRE recombinase activity without or with the CRE T-DNA being integrated, transient expression versus stable transformation was differentiated. During root explant cocultivation, continuous light enhanced the number of plant cells competent for interaction with Agrobacterium and thus the number of transient gene expression events. However, in transformation competent plant cells, continuous light did not further enhance cotransfer or cointegration frequencies. Upon selection for root transformants expressing a first T-DNA, 43-69 % of these transformants showed cotransfer of another non-selected T-DNA in two different light regimes. However, integration of the non-selected cotransferred T-DNA occurred only in 19-46 % of these transformants, indicating that T-DNA integration in regenerating root cells limits the transformation frequencies. After floral dip transformation, transient T-DNA expression without integration could not be detected, while stable T-DNA transformation occurred in 0.5-1.3 % of the T1 seedlings. Upon selection for floral dip transformants with a first T-DNA, 8-34 % of the transformants showed cotransfer of the other non-selected T-DNA and in 93-100 % of them, the T-DNA was also integrated. Therefore, a productive interaction between the agrobacteria and the female gametophyte, rather than the T-DNA integration process, restricts the floral dip transformation frequencies.

Fault diagnosis of power transformer based on fault-tree analysis (FTA)

Science.gov (United States)

Wang, Yongliang; Li, Xiaoqiang; Ma, Jianwei; Li, SuoYu

2017-05-01

Power transformers is an important equipment in power plants and substations, power distribution transmission link is made an important hub of power systems. Its performance directly affects the quality and health of the power system reliability and stability. This paper summarizes the five parts according to the fault type power transformers, then from the time dimension divided into three stages of power transformer fault, use DGA routine analysis and infrared diagnostics criterion set power transformer running state, finally, according to the needs of power transformer fault diagnosis, by the general to the section by stepwise refinement of dendritic tree constructed power transformer fault

Quantitative subsurface analysis using frequency modulated thermal wave imaging

Science.gov (United States)

Subhani, S. K.; Suresh, B.; Ghali, V. S.

2018-01-01

Quantitative depth analysis of the anomaly with an enhanced depth resolution is a challenging task towards the estimation of depth of the subsurface anomaly using thermography. Frequency modulated thermal wave imaging introduced earlier provides a complete depth scanning of the object by stimulating it with a suitable band of frequencies and further analyzing the subsequent thermal response using a suitable post processing approach to resolve subsurface details. But conventional Fourier transform based methods used for post processing unscramble the frequencies with a limited frequency resolution and contribute for a finite depth resolution. Spectral zooming provided by chirp z transform facilitates enhanced frequency resolution which can further improves the depth resolution to axially explore finest subsurface features. Quantitative depth analysis with this augmented depth resolution is proposed to provide a closest estimate to the actual depth of subsurface anomaly. This manuscript experimentally validates this enhanced depth resolution using non stationary thermal wave imaging and offers an ever first and unique solution for quantitative depth estimation in frequency modulated thermal wave imaging.

High-frequency magnetic components

CERN Document Server

Kazimierczuk, Marian K

2013-01-01

A unique text on the theory and design fundaments of inductors and transformers, updated with more coverage on the optimization of magnetic devices and many new design examples The first edition is popular among a very broad audience of readers in different areas of engineering and science. This book covers the theory and design techniques of the major types of high-frequency power inductors and transformers for a variety of applications, including switching-mode power supplies (SMPS) and resonant dc-to-ac power inverters and dc-to-dc power converters. It describes eddy-current phenomena (su

Electronic voltage and current transformers testing device.

Science.gov (United States)

Pan, Feng; Chen, Ruimin; Xiao, Yong; Sun, Weiming

2012-01-01

A method for testing electronic instrument transformers is described, including electronic voltage and current transformers (EVTs, ECTs) with both analog and digital outputs. A testing device prototype is developed. It is based on digital signal processing of the signals that are measured at the secondary outputs of the tested transformer and the reference transformer when the same excitation signal is fed to their primaries. The test that estimates the performance of the prototype has been carried out at the National Centre for High Voltage Measurement and the prototype is approved for testing transformers with precision class up to 0.2 at the industrial frequency (50 Hz or 60 Hz). The device is suitable for on-site testing due to its high accuracy, simple structure and low-cost hardware.

Research on Shore-Ship Photonic Link Performance for Two- Frequency-Band Signals

Science.gov (United States)

Zuo, Yanqin; Cong, Bo

2016-02-01

Ka and Ku bands links for shore-ship communications suffer limited bandwidth and high loss. In this paper, photonics-based links are proposed and modeled. The principle of phase modulation (PM) is elaborated and analyzed. It is showed that PM can effectively suppress high-order inter-modulation distortion (IMD), reduce the insert loss and improve the reliability of the system.

Performance of Reverse-Link Synchronous DS-CDMA System on a Frequency-Selective Multipath Fading Channel with Imperfect Power Control

Directory of Open Access Journals (Sweden)

Duk Kyung Kim

2002-08-01

Full Text Available We analyze the performance for reverse-link synchronous DS-CDMA system in a frequency-selective Rayleigh fading channel with an imperfect power control scheme. The performance degradation due to power control error (PCE, which is approximated by a log-normally distributed random variable, is estimated as a function of the standard deviation of the PCE. In addition, we investigate the impacts of the multipath intensity profile (MIP shape and the number of resolvable paths on the performance. Finally, the coded bit error performance is evaluated in order to estimate the system capacity. Comparing with the conventional CDMA system, we show an achievable gain of from 59% to 23% for reverse-link synchronous transmission technique (RLSTT in the presence of imperfect power control over asynchronous transmission for BER=10−6. As well, the effect of tradeoff between orthogonality and diversity can be seen according to the number of multipaths, and the tendency is kept even in the presence of PCE. We conclude that the capacity can be further improved via the RLSTT, because the DS-CDMA system is very sensitive to power control imperfections.

High frequency measurement of nitrate concentration in the Lower Mississippi River, USA

Science.gov (United States)

Duan, Shuiwang; Powell, Rodney T.; Bianchi, Thomas S.

2014-11-01

Nutrient concentrations in the Mississippi River have increased dramatically since the 1950s, and high frequency measurements on nitrate concentration are required for accurate load estimations and examinations on nitrate transport and transformation processes. This three year record of high temporal resolution (every 2-3 h) data clearly illustrates the importance of high frequency sampling in improving load estimates and resolving variations in nitrate concentration with river flow and tributary inputs. Our results showed large short-term (days to weeks) variations in nitrate concentration but with no diurnal patterns. A repeatable and pronounced seasonal pattern of nitrate concentration was observed, and showed gradual increases from the lowest values in September (during base-flow), to the highest in June - which was followed by a rapid decrease. This seasonal pattern was only moderately linked with water discharge, and more controlled by nitrogen transformation/export from watershed as well as mixing patterns of the two primary tributaries (the upper Mississippi and the Ohio Rivers), which have distinctly different nitrate concentrations and flow patterns. Based on continuous in situ flow measurements, we estimated 554-886 × 106 kg of nitrate-N was exported from the Mississippi River system during years 2004-2006, which was <9% and <16% lower than U.S. Geological Survey's (USGS) estimates using their LOADEST or composite methods, respectively. USGS methods generally overestimated nitrate loads during rising stages and underestimated the loads during falling stages. While changes in nitrate concentrations in large rivers are generally not as responsive to alterations in diurnal inputs and/or watershed hydrology as small rivers, high-frequency water quality sampling would help in monitoring short-term (days to weeks) variations in nutrient concentration patterns and thus improve the accuracy of nutrient flux estimates.

STUDY REGARDING EFFICIENCY OF INDUCED GENETIC TRANSFORMATION IN BACILLUS LICHENIFORMIS WITH PLASMID DNA

Directory of Open Access Journals (Sweden)

T. VINTILĂ

2007-05-01

Full Text Available A strain of Bacillus licheniformis was subject to genetic transformation with plasmid vectors (pLC1 and pNC61, using electroporation technique, protoplast transformation and bivalent cations (CaCl2 mediated transformation. In the case of transformation by electroporation of Bacillus licheniformis B40, the highest number of transformed colonies (3 were obtained only after a 1,79 KV electric shock, for 2,2 milliseconds. Using this transformation technique we have obtained six kanamycin resistant transformants. The frequency of Bacillus licheniformis B40 protoplasts transformation using pLC1 and pNC61 plasmid vectors is approximately 10% (TF = 10%. As a result of pLC1 plasmid integration in Bacillus licheniformis protoplasts, six kanamycin resistant transformants were obtained. The pNC61 plasmid, which confers trimethoprim resistance, does not integrate in receiver cells by protoplast transformation. The direct genetic transformation in the presence of bivalent cations (CaCl2, mediated by pLC1 and pNC61 plasmid vectors, produce a low transformation frequency. Using this technique, we have obtained three trimethoprim resistant colonies and four kanamycin resistant colonies. The chemical way of transformation is the only technique, which realizes the integration of pNC61 in B. licheniformis B40 cells.

Integrated magnetics design for HF-link power converters

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.; Andersen, Michael A.E.

2005-07-01

This paper deals with the design of integrated magnetics for HF-link converters, where the two integrated magnetic components on the same core do not necessarily belong to the same voltage loop. Depending on the specific HF-link converter topology, the proposed integrated magnetics can either alleviate the derivation of independent auxiliary supply voltages from the main transformer or integrate other magnetic structures, thus saving board space and cutting costs. (au)

High-frequency combination coding-based steady-state visual evoked potential for brain computer interface

Energy Technology Data Exchange (ETDEWEB)

Zhang, Feng; Zhang, Xin; Xie, Jun; Li, Yeping; Han, Chengcheng; Lili, Li; Wang, Jing [School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Xu, Guang-Hua [School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710054 (China)

2015-03-10

This study presents a new steady-state visual evoked potential (SSVEP) paradigm for brain computer interface (BCI) systems. The goal of this study is to increase the number of targets using fewer stimulation high frequencies, with diminishing subject’s fatigue and reducing the risk of photosensitive epileptic seizures. The new paradigm is High-Frequency Combination Coding-Based High-Frequency Steady-State Visual Evoked Potential (HFCC-SSVEP).Firstly, we studied SSVEP high frequency(beyond 25 Hz)response of SSVEP, whose paradigm is presented on the LED. The SNR (Signal to Noise Ratio) of high frequency(beyond 40 Hz) response is very low, which is been unable to be distinguished through the traditional analysis method; Secondly we investigated the HFCC-SSVEP response (beyond 25 Hz) for 3 frequencies (25Hz, 33.33Hz, and 40Hz), HFCC-SSVEP produces n{sup n} with n high stimulation frequencies through Frequence Combination Code. Further, Animproved Hilbert-huang transform (IHHT)-based variable frequency EEG feature extraction method and a local spectrum extreme target identification algorithmare adopted to extract time-frequency feature of the proposed HFCC-SSVEP response.Linear predictions and fixed sifting (iterating) 10 time is used to overcome the shortage of end effect and stopping criterion,generalized zero-crossing (GZC) is used to compute the instantaneous frequency of the proposed SSVEP respondent signals, the improved HHT-based feature extraction method for the proposed SSVEP paradigm in this study increases recognition efficiency, so as to improve ITR and to increase the stability of the BCI system. what is more, SSVEPs evoked by high-frequency stimuli (beyond 25Hz) minimally diminish subject’s fatigue and prevent safety hazards linked to photo-induced epileptic seizures, So as to ensure the system efficiency and undamaging.This study tests three subjects in order to verify the feasibility of the proposed method.

High-frequency combination coding-based steady-state visual evoked potential for brain computer interface

International Nuclear Information System (INIS)

Zhang, Feng; Zhang, Xin; Xie, Jun; Li, Yeping; Han, Chengcheng; Lili, Li; Wang, Jing; Xu, Guang-Hua

2015-01-01

This study presents a new steady-state visual evoked potential (SSVEP) paradigm for brain computer interface (BCI) systems. The goal of this study is to increase the number of targets using fewer stimulation high frequencies, with diminishing subject’s fatigue and reducing the risk of photosensitive epileptic seizures. The new paradigm is High-Frequency Combination Coding-Based High-Frequency Steady-State Visual Evoked Potential (HFCC-SSVEP).Firstly, we studied SSVEP high frequency(beyond 25 Hz)response of SSVEP, whose paradigm is presented on the LED. The SNR (Signal to Noise Ratio) of high frequency(beyond 40 Hz) response is very low, which is been unable to be distinguished through the traditional analysis method; Secondly we investigated the HFCC-SSVEP response (beyond 25 Hz) for 3 frequencies (25Hz, 33.33Hz, and 40Hz), HFCC-SSVEP produces n n with n high stimulation frequencies through Frequence Combination Code. Further, Animproved Hilbert-huang transform (IHHT)-based variable frequency EEG feature extraction method and a local spectrum extreme target identification algorithmare adopted to extract time-frequency feature of the proposed HFCC-SSVEP response.Linear predictions and fixed sifting (iterating) 10 time is used to overcome the shortage of end effect and stopping criterion,generalized zero-crossing (GZC) is used to compute the instantaneous frequency of the proposed SSVEP respondent signals, the improved HHT-based feature extraction method for the proposed SSVEP paradigm in this study increases recognition efficiency, so as to improve ITR and to increase the stability of the BCI system. what is more, SSVEPs evoked by high-frequency stimuli (beyond 25Hz) minimally diminish subject’s fatigue and prevent safety hazards linked to photo-induced epileptic seizures, So as to ensure the system efficiency and undamaging.This study tests three subjects in order to verify the feasibility of the proposed method

Feasibility analysis of WDM links for radar applications

Directory of Open Access Journals (Sweden)

D. Meena

2015-03-01

Full Text Available Active phased array antennas enhances the performance of modern radars by using multiple low power transmit/receive modules in place of a high power transmitter in conventional radars. Fully distributed phased array radars demand the distribution of various signals in radio frequency (RF and digital domain for real time operation. This is normally achieved through complex and bulky coaxial distribution networks. In this work, we intend to tap the inherent advantages of fiber links with wavelength division multiplexed (WDM technology and a feasibility study to adapt these links for radar applications is carried out. This is done by analysing various parameters like amplitude, delay, frequency and phase variation response of various radar waveforms over WDM links. This also includes performance evaluation of non-linear frequency modulation (NLFM signals, known for better signal to noise ratio (SNR to specific side lobe levels. NLFM waveforms are further analysed using pulse compression (PC technique. Link evaluation is also carried out using a standard simulation environment and is then experimentally verified with other waveforms like RF continuous wave (CW, pulsed RF and digital signals. Synchronization signals are generated from this variable duty cycle digital signals during real time radar operation. During evaluation of digital signals, variable transient effects for different duty cycles are observed from an amplifier configuration. A suppression method is proposed to eliminate this transient effects. Further, the link delay response is investigated using different lengths of fiber spools. It can be inferred from the experimental results that WDM links are capable of handling various signals significant to radar applications.

A high-switching-frequency flyback converter in resonant mode

NARCIS (Netherlands)

Li, Jianting; van Horck, Frank B.M.; Daniel, Bobby J.; Bergveld, Henk Jan

2017-01-01

The demand of miniaturization of power systems has accelerated the research on high-switching-frequency power converters. A flyback converter in resonant mode that features low switching losses, less transformer losses, and low switching noise at high switching frequency is investigated in this

Efficient 3D frequency response modeling with spectral accuracy by the rapid expansion method

KAUST Repository

Chu, Chunlei

2012-07-01

Frequency responses of seismic wave propagation can be obtained either by directly solving the frequency domain wave equations or by transforming the time domain wavefields using the Fourier transform. The former approach requires solving systems of linear equations, which becomes progressively difficult to tackle for larger scale models and for higher frequency components. On the contrary, the latter approach can be efficiently implemented using explicit time integration methods in conjunction with running summations as the computation progresses. Commonly used explicit time integration methods correspond to the truncated Taylor series approximations that can cause significant errors for large time steps. The rapid expansion method (REM) uses the Chebyshev expansion and offers an optimal solution to the second-order-in-time wave equations. When applying the Fourier transform to the time domain wavefield solution computed by the REM, we can derive a frequency response modeling formula that has the same form as the original time domain REM equation but with different summation coefficients. In particular, the summation coefficients for the frequency response modeling formula corresponds to the Fourier transform of those for the time domain modeling equation. As a result, we can directly compute frequency responses from the Chebyshev expansion polynomials rather than the time domain wavefield snapshots as do other time domain frequency response modeling methods. When combined with the pseudospectral method in space, this new frequency response modeling method can produce spectrally accurate results with high efficiency. © 2012 Society of Exploration Geophysicists.

Method for Assessing Grid Frequency Deviation Due to Wind Power Fluctuation Based on “Time-Frequency Transformation”

DEFF Research Database (Denmark)

Jin, Lin; Yuan-zhang, Sun; Sørensen, Poul Ejnar

2012-01-01

published studies are based entirely on deterministic methodology. This paper presents a novel assessment method based on Time-Frequency Transformation to overcome shortcomings of existing methods. The main contribution of the paper is to propose a stochastic process simulation model which is a better...... alternative of the existing dynamic frequency deviation simulation model. In this way, the method takes the stochastic wind power fluctuation into full account so as to give a quantitative risk assessment of grid frequency deviation to grid operators, even without using any dynamic simulation tool. The case...

Input preshaping with frequency domain information for flexible-link manipulator control

Science.gov (United States)

Tzes, Anthony; Englehart, Matthew J.; Yurkovich, Stephen

1989-01-01

The application of an input preshaping scheme to flexible manipulators is considered. The resulting control corresponds to a feedforward term that convolves in real-time the desired reference input with a sequence of impulses and produces a vibration free output. The robustness of the algorithm with respect to injected disturbances and modal frequency variations is not satisfactory and can be improved by convolving the input with a longer sequence of impulses. The incorporation of the preshaping scheme to a closed-loop plant, using acceleration feedback, offers satisfactory disturbance rejection due to feedback and cancellation of the flexible mode effects due to the preshaping. A frequency domain identification scheme is used to estimate the modal frequencies on-line and subsequently update the spacing between the impulses. The combined adaptive input preshaping scheme provides the fastest possible slew that results in a vibration free output.

Urbanization causes shifts in species' trait state frequencies

NARCIS (Netherlands)

Knapp, S.; Kühn, I.; Wittig, R.; Ozinga, W.A.; Poschlod, P.; Klotz, S.

2008-01-01

Urbanization is one of the most extreme forms of land transformation. It is supposed to change the frequencies of species trait states in species assemblages.We hypothesize that the flora of urban and rural areas differs in the frequency of trait states and ask which traits enable a plant to cope

A new method of hybrid frequency hopping signals selection and blind parameter estimation

Science.gov (United States)

Zeng, Xiaoyu; Jiao, Wencheng; Sun, Huixian

2018-04-01

Frequency hopping communication is widely used in military communications at home and abroad. In the case of single-channel reception, it is scarce to process multiple frequency hopping signals both effectively and simultaneously. A method of hybrid FH signals selection and blind parameter estimation is proposed. The method makes use of spectral transformation, spectral entropy calculation and PRI transformation basic theory to realize the sorting and parameter estimation of the components in the hybrid frequency hopping signal. The simulation results show that this method can correctly classify the frequency hopping component signal, and the estimated error of the frequency hopping period is about 5% and the estimated error of the frequency hopping frequency is less than 1% when the SNR is 10dB. However, the performance of this method deteriorates seriously at low SNR.

Soliton solutions of the (2 + 1)-dimensional Harry Dym equation via Darboux transformation

International Nuclear Information System (INIS)

Halim, A.A.

2008-01-01

This work introduces solitons solutions for the (2 + 1)-dimensional Harry Dym equation using Darboux transformation. The link between the (2 + 1)-dimensional Harry Dym equation and the linear system associated with the modified Kadomtzev-Patvishvili equation is used. Namely, soliton solutions for the linear system associated with the later equation are produced using Darboux transformation. These solutions are inserted in the mentioned link to produce soliton solutions for the (2 + 1)-dimensional Harry Dym equation

Sweeping a persisting superconducting magnet with a transformer

International Nuclear Information System (INIS)

Spencer, G.F.; Alexander, P.W.; Ihas, G.G.

1982-01-01

A method for sweeping a persisting superconducting magnet is described. The field sweep is achieved by including in the superconducting loop of the magnet a coil which acts as the secondary coil of a transformer. Variation of the current in the primary coil of the transformer, controlled from outside the cryostat, causes the field-sweeping action through flux-linking with the superconducting loop. Compared to directly changing the current in a magnet, this technique improves control by the ratio of the magnet's inductance to the transformer's inductance. The advantages of using an all-metal vacuum-tight superconducting feedthrough are discussed. (author)

Multi-Beam Radio Frequency (RF) Aperture Arrays Using Multiplierless Approximate Fast Fourier Transform (FFT)

Science.gov (United States)

2017-08-01

Fourier transform, discrete Fourier transform, digital array processing , antenna beamformers 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...125 3.7 Simulation of 2-D Beams Cross Sections .................................................................... 125 3.7.1 8...unlimited. List of Figures Figure Page Figure 1: N-beam Array Processing System using a Linear Array

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.

Frequency-Shift Detectors Bind Binaural as Well as Monaural Frequency Representations

Science.gov (United States)

Carcagno, Samuele; Semal, Catherine; Demany, Laurent

2011-01-01

Previous psychophysical work provided evidence for the existence of automatic frequency-shift detectors (FSDs) that establish perceptual links between successive sounds. In this study, we investigated the characteristics of the FSDs with respect to the binaural system. Listeners were presented with sound sequences consisting of a chord of pure…

Stable transmission of radio frequency signals on fiber links using interferomectric delay sensing

International Nuclear Information System (INIS)

Wilcox, Russell B.; Byrd, J.M.; Doolittle, Lawrence; Huang, Gang; Staples, J.W.

2009-01-01

The authors demonstrate distribution of a 2850 MHz rf signal over stabilized optical fiber links. For a 2.2 km link they measure an rms drift of 19.4 fs over 60 h, and for a 200 m link an rms drift of 8.4 fs over 20 h. The rf signals are transmitted as amplitude modulation on a continuous optical carrier. Variations in the delay length are sensed using heterodyne interferometry and used to correct the rf phase. The system uses standard fiber telecommunications components.

Applications of ferro-nanofluid on a micro-transformer.

Science.gov (United States)

Tsai, Tsung-Han; Kuo, Long-Sheng; Chen, Ping-Hei; Lee, Da-Sheng; Yang, Chin-Ting

2010-01-01

An on-chip transformer with a ferrofluid magnetic core has been developed and tested. The transformer consists of solenoid-type coil and a magnetic core of ferrofluid, with the former fabricated by MEMS technology and the latter by a chemical co-precipitation method. The performance of the MEMS transformer with a ferrofluid magnetic core was measured and simulated with frequencies ranging from 100 kHz to 100 MHz. Experimental results reveal that the presence of the ferrofluid increases the inductance of coils and the coupling coefficient of transformer; however, it also increases the resistance owing to the lag between the external magnetic field and the magnetization of the material.

Gear Fault Detection Based on Teager-Huang Transform

Directory of Open Access Journals (Sweden)

Hui Li

2010-01-01

Full Text Available Gear fault detection based on Empirical Mode Decomposition (EMD and Teager Kaiser Energy Operator (TKEO technique is presented. This novel method is named as Teager-Huang transform (THT. EMD can adaptively decompose the vibration signal into a series of zero mean Intrinsic Mode Functions (IMFs. TKEO can track the instantaneous amplitude and instantaneous frequency of the Intrinsic Mode Functions at any instant. The experimental results provide effective evidence that Teager-Huang transform has better resolution than that of Hilbert-Huang transform. The Teager-Huang transform can effectively diagnose the fault of the gear, thus providing a viable processing tool for gearbox defect detection and diagnosis.

Inverse kinematics algorithm for a six-link manipulator using a polynomial expression

International Nuclear Information System (INIS)

Sasaki, Shinobu

1987-01-01

This report is concerned with the forward and inverse kinematics problem relevant to a six-link robot manipulator. In order to derive the kinematic relationships between links, the vector rotation operator was applied instead of the conventional homogeneous transformation. The exact algorithm for solving the inverse problem was obtained by transforming kinematics equations into a polynomial. As shown in test calculations, the accuracies of numerical solutions obtained by means of the present approach are found to be quite high. The algorithm proposed permits to find out all feasible solutions for the given inverse problem. (author)

Cascaded optical fiber link using the internet network for remote clocks comparison.

Science.gov (United States)

Chiodo, Nicola; Quintin, Nicolas; Stefani, Fabio; Wiotte, Fabrice; Camisard, Emilie; Chardonnet, Christian; Santarelli, Giorgio; Amy-Klein, Anne; Pottie, Paul-Eric; Lopez, Olivier

2015-12-28

We report a cascaded optical link of 1100 km for ultra-stable frequency distribution over an Internet fiber network. The link is composed of four spans for which the propagation noise is actively compensated. The robustness and the performance of the link are ensured by five fully automated optoelectronic stations, two of them at the link ends, and three deployed on the field and connecting the spans. This device coherently regenerates the optical signal with the heterodyne optical phase locking of a low-noise laser diode. Optical detection of the beat-note signals for the laser lock and the link noise compensation are obtained with stable and low-noise fibered optical interferometer. We show 3.5 days of continuous operation of the noise-compensated 4-span cascaded link leading to fractional frequency instability of 4x10(-16) at 1-s measurement time and 1x10(-19) at 2000 s. This cascaded link was extended to 1480-km with the same performance. This work is a significant step towards a sustainable wide area ultra-stable optical frequency distribution and comparison network at a very high level of performance.

Online frequency estimation with applications to engine and generator sets

Science.gov (United States)

Manngård, Mikael; Böling, Jari M.

2017-07-01

Frequency and spectral analysis based on the discrete Fourier transform is a fundamental task in signal processing and machine diagnostics. This paper aims at presenting computationally efficient methods for real-time estimation of stationary and time-varying frequency components in signals. A brief survey of the sliding time window discrete Fourier transform and Goertzel filter is presented, and two filter banks consisting of: (i) sliding time window Goertzel filters (ii) infinite impulse response narrow bandpass filters are proposed for estimating instantaneous frequencies. The proposed methods show excellent results on both simulation studies and on a case study using angular speed data measurements of the crankshaft of a marine diesel engine-generator set.

Image secure transmission for optical orthogonal frequency-division multiplexing visible light communication systems using chaotic discrete cosine transform

Science.gov (United States)

Wang, Zhongpeng; Zhang, Shaozhong; Chen, Fangni; Wu, Ming-Wei; Qiu, Weiwei

2017-11-01

A physical encryption scheme for orthogonal frequency-division multiplexing (OFDM) visible light communication (VLC) systems using chaotic discrete cosine transform (DCT) is proposed. In the scheme, the row of the DCT matrix is permutated by a scrambling sequence generated by a three-dimensional (3-D) Arnold chaos map. Furthermore, two scrambling sequences, which are also generated from a 3-D Arnold map, are employed to encrypt the real and imaginary parts of the transmitted OFDM signal before the chaotic DCT operation. The proposed scheme enhances the physical layer security and improves the bit error rate (BER) performance for OFDM-based VLC. The simulation results prove the efficiency of the proposed encryption method. The experimental results show that the proposed security scheme not only protects image data from eavesdroppers but also keeps the good BER and peak-to-average power ratio performances for image-based OFDM-VLC systems.

Acceleration transforms and statistical kinetic models

International Nuclear Information System (INIS)

LuValle, M.J.; Welsher, T.L.; Svoboda, K.

1988-01-01

For a restricted class of problems a mathematical model of microscopic degradation processes, statistical kinetics, is developed and linked through acceleration transforms to the information which can be obtained from a system in which the only observable sign of degradation is sudden and catastrophic failure. The acceleration transforms were developed in accelerated life testing applications as a tool for extrapolating from the observable results of an accelerated life test to the dynamics of the underlying degradation processes. A particular concern of a physicist attempting to interpreted the results of an analysis based on acceleration transforms is determining the physical species involved in the degradation process. These species may be (a) relatively abundant or (b) relatively rare. The main results of this paper are a theorem showing that for an important subclass of statistical kinetic models, acceleration transforms cannot be used to distinguish between cases a and b, and an example showing that in some cases falling outside the restrictions of the theorem, cases a and b can be distinguished by their acceleration transforms

Fault detection of gearbox using time-frequency method

Science.gov (United States)

Widodo, A.; Satrijo, Dj.; Prahasto, T.; Haryanto, I.

2017-04-01

This research deals with fault detection and diagnosis of gearbox by using vibration signature. In this work, fault detection and diagnosis are approached by employing time-frequency method, and then the results are compared with cepstrum analysis. Experimental work has been conducted for data acquisition of vibration signal thru self-designed gearbox test rig. This test-rig is able to demonstrate normal and faulty gearbox i.e., wears and tooth breakage. Three accelerometers were used for vibration signal acquisition from gearbox, and optical tachometer was used for shaft rotation speed measurement. The results show that frequency domain analysis using fast-fourier transform was less sensitive to wears and tooth breakage condition. However, the method of short-time fourier transform was able to monitor the faults in gearbox. Wavelet Transform (WT) method also showed good performance in gearbox fault detection using vibration signal after employing time synchronous averaging (TSA).

An improved ternary vector system for Agrobacterium-mediated rapid maize transformation.

Science.gov (United States)

Anand, Ajith; Bass, Steven H; Wu, Emily; Wang, Ning; McBride, Kevin E; Annaluru, Narayana; Miller, Michael; Hua, Mo; Jones, Todd J

2018-05-01

A simple and versatile ternary vector system that utilizes improved accessory plasmids for rapid maize transformation is described. This system facilitates high-throughput vector construction and plant transformation. The super binary plasmid pSB1 is a mainstay of maize transformation. However, the large size of the base vector makes it challenging to clone, the process of co-integration is cumbersome and inefficient, and some Agrobacterium strains are known to give rise to spontaneous mutants resistant to tetracycline. These limitations present substantial barriers to high throughput vector construction. Here we describe a smaller, simpler and versatile ternary vector system for maize transformation that utilizes improved accessory plasmids requiring no co-integration step. In addition, the newly described accessory plasmids have restored virulence genes found to be defective in pSB1, as well as added virulence genes. Testing of different configurations of the accessory plasmids in combination with T-DNA binary vector as ternary vectors nearly doubles both the raw transformation frequency and the number of transformation events of usable quality in difficult-to-transform maize inbreds. The newly described ternary vectors enabled the development of a rapid maize transformation method for elite inbreds. This vector system facilitated screening different origins of replication on the accessory plasmid and T-DNA vector, and four combinations were identified that have high (86-103%) raw transformation frequency in an elite maize inbred.

A gravitational wave burst search method based on the S transform

International Nuclear Information System (INIS)

Clapson, Andre-Claude; Barsuglia, Matteo; Bizouard, Marie-Anne; Brisson, Violette; Cavalier, Fabien; Davier, Michel; Hello, Patrice; Kreckelberg, Stephane; Varvella, Monica

2005-01-01

The detection of burst-type events in the output of ground gravitational wave observatories is particularly challenging due to the expected variety of astrophysical waveforms and the issue of discriminating them from instrumental noise. Robust methods, that achieve reasonable detection performances over a wide range of signals, would be most useful. We present a burst-detection pipeline based on a time-frequency transform, the S transform. This transform offers good time-frequency localization of energy without requiring prior knowledge of the event structure. We set a simple (and robust) event extraction chain. Results are provided for a variety of signals injected in simulated Gaussian statistics data (from the LIGO-Virgo joint working group). Indications are that detection is robust with respect to event type and that efficiency compares reasonably with reference methods. The time-frequency representation is shown to be affected by spectral features such as resonant lines. This emphasizes the role of pre-processing

A gravitational wave burst search method based on the S transform

Energy Technology Data Exchange (ETDEWEB)

Clapson, Andre-Claude; Barsuglia, Matteo; Bizouard, Marie-Anne; Brisson, Violette; Cavalier, Fabien; Davier, Michel; Hello, Patrice; Kreckelberg, Stephane; Varvella, Monica [Groupe Virgo, LAL, Universite Paris-Sud, Batiment 208, BP 34, F-91898 Orsay Cedex (France)

2005-09-21

The detection of burst-type events in the output of ground gravitational wave observatories is particularly challenging due to the expected variety of astrophysical waveforms and the issue of discriminating them from instrumental noise. Robust methods, that achieve reasonable detection performances over a wide range of signals, would be most useful. We present a burst-detection pipeline based on a time-frequency transform, the S transform. This transform offers good time-frequency localization of energy without requiring prior knowledge of the event structure. We set a simple (and robust) event extraction chain. Results are provided for a variety of signals injected in simulated Gaussian statistics data (from the LIGO-Virgo joint working group). Indications are that detection is robust with respect to event type and that efficiency compares reasonably with reference methods. The time-frequency representation is shown to be affected by spectral features such as resonant lines. This emphasizes the role of pre-processing.

Mechanisms of radiation-induced neoplastic cell transformation

Energy Technology Data Exchange (ETDEWEB)

Yang, T.C.H.; Tobias, C.A.

1984-04-01

Studies with cultured mammalian cells demonstrated clearly that radiation can transform cells directly and can enhance the cell transformation by oncogenic DNA viruses. In general, high-LET heavy-ion radiation can be more effective than X and gamma rays in inducing neoplastic cell transformation. Various experimental results indicate that radiation-induced DNA damage, most likely double-strand breaks, is important for both the initiation of cell transformation and for the enhancement of viral transformation. Some of the transformation and enhancement lesions can be repaired properly in the cell, and the amount of irrepairable lesions produced by a given dose depends on the quality of radiation. An inhibition of repair processes with chemical agents can increase the transformation frequency of cells exposed to radiation and/or oncogenic viruses, suggesting that repair mechanisms may play an important role in the radiation transformation. The progression of radiation-transformed cells appears to be a long and complicated process that can be modulated by some nonmutagenic chemical agents, e.g., DMSO. Normal cells can inhibit the expression of transforming properties of tumorigenic cells through an as yet unknown mechanism. The progression and expression of transformation may involve some epigenetic changes in the irradiated cells. 38 references, 15 figures, 1 table.

Mechanisms of radiation-induced neoplastic cell transformation

International Nuclear Information System (INIS)

Yang, T.C.H.; Tobias, C.A.

1984-04-01

Studies with cultured mammalian cells demonstrated clearly that radiation can transform cells directly and can enhance the cell transformation by oncogenic DNA viruses. In general, high-LET heavy-ion radiation can be more effective than X and gamma rays in inducing neoplastic cell transformation. Various experimental results indicate that radiation-induced DNA damage, most likely double-strand breaks, is important for both the initiation of cell transformation and for the enhancement of viral transformation. Some of the transformation and enhancement lesions can be repaired properly in the cell, and the amount of irrepairable lesions produced by a given dose depends on the quality of radiation. An inhibition of repair processes with chemical agents can increase the transformation frequency of cells exposed to radiation and/or oncogenic viruses, suggesting that repair mechanisms may play an important role in the radiation transformation. The progression of radiation-transformed cells appears to be a long and complicated process that can be modulated by some nonmutagenic chemical agents, e.g., DMSO. Normal cells can inhibit the expression of transforming properties of tumorigenic cells through an as yet unknown mechanism. The progression and expression of transformation may involve some epigenetic changes in the irradiated cells. 38 references, 15 figures, 1 table

An assessment of envelope-based demodulation in case of proximity of carrier and modulation frequencies

Science.gov (United States)

Shahriar, Md Rifat; Borghesani, Pietro; Randall, R. B.; Tan, Andy C. C.

2017-11-01

Demodulation is a necessary step in the field of diagnostics to reveal faults whose signatures appear as an amplitude and/or frequency modulation. The Hilbert transform has conventionally been used for the calculation of the analytic signal required in the demodulation process. However, the carrier and modulation frequencies must meet the conditions set by the Bedrosian identity for the Hilbert transform to be applicable for demodulation. This condition, basically requiring the carrier frequency to be sufficiently higher than the frequency of the modulation harmonics, is usually satisfied in many traditional diagnostic applications (e.g. vibration analysis of gear and bearing faults) due to the order-of-magnitude ratio between the carrier and modulation frequency. However, the diversification of the diagnostic approaches and applications shows cases (e.g. electrical signature analysis-based diagnostics) where the carrier frequency is in close proximity to the modulation frequency, thus challenging the applicability of the Bedrosian theorem. This work presents an analytic study to quantify the error introduced by the Hilbert transform-based demodulation when the Bedrosian identity is not satisfied and proposes a mitigation strategy to combat the error. An experimental study is also carried out to verify the analytical results. The outcome of the error analysis sets a confidence limit on the estimated modulation (both shape and magnitude) achieved through the Hilbert transform-based demodulation in case of violated Bedrosian theorem. However, the proposed mitigation strategy is found effective in combating the demodulation error aroused in this scenario, thus extending applicability of the Hilbert transform-based demodulation.

Applications of Fourier transforms to generalized functions

CERN Document Server

Rahman, M

2011-01-01

This book explains how Fourier transforms can be applied to generalized functions. The generalized function is one of the important branches of mathematics and is applicable in many practical fields. Its applications to the theory of distribution and signal processing are especially important. The Fourier transform is a mathematical procedure that can be thought of as transforming a function from its time domain to the frequency domain.The book contains six chapters and three appendices. Chapter 1 deals with preliminary remarks on Fourier series from a general point of view and also contains an introduction to the first generalized function. Chapter 2 is concerned with the generalized functions and their Fourier transforms. Chapter 3 contains the Fourier transforms of particular generalized functions. The author has stated and proved 18 formulas dealing with the Fourier transforms of generalized functions, and demonstrated some important problems of practical interest. Chapter 4 deals with the asymptotic esti...

Development and verification of printed circuit board toroidal transformer model

DEFF Research Database (Denmark)

Pejtersen, Jens; Mønster, Jakob Døllner; Knott, Arnold

2013-01-01

An analytical model of an air core printed circuit board embedded toroidal transformer configuration is presented. The transformer has been developed for galvanic isolation of very high frequency switch-mode dc-dc power converter applications. The theoretical model is developed and verified...... by comparing calculated parameters with 3D finite element simulations and experimental measurement results. The developed transformer model shows good agreement with the simulated and measured results. The model can be used to predict the parameters of printed circuit board toroidal transformer configurations...

The role of nutritional factors in cellular protection against DNA damage, altered gene expression and malignant transformation

International Nuclear Information System (INIS)

Borek, C.

1986-01-01

In recent years data from epidemiological studies and laboratory experiments have revealed numerous links between diet and cancer. The complex role of nutritional factors in modifying cancer incidence may be attributed in part to dietary agents acting as potentiators or promoters of cancer, serving as auxilliary agents to other environmental factors; as causes of cancer, or as cancer preventive agents. Studies can be carried on in vitro, in cell culture systems, where malignant transformation serves as an end point. These systems afford the opportunity to study the direct effect of nutrition in oncogenesis and the role of dietary factors in modulating the frequency and course of neoplastic development in its various stages. 20 refs., 1 fig., 3 tabs

Frame transforms, star products and quantum mechanics on phase space

International Nuclear Information System (INIS)

Aniello, P; Marmo, G; Man'ko, V I

2008-01-01

Using the notions of frame transform and of square integrable projective representation of a locally compact group G, we introduce a class of isometries (tight frame transforms) from the space of Hilbert-Schmidt operators in the carrier Hilbert space of the representation into the space of square integrable functions on the direct product group G x G. These transforms have remarkable properties. In particular, their ranges are reproducing kernel Hilbert spaces endowed with a suitable 'star product' which mimics, at the level of functions, the original product of operators. A 'phase space formulation' of quantum mechanics relying on the frame transforms introduced in the present paper, and the link of these maps with both the Wigner transform and the wavelet transform are discussed

Digitized self-oscillating loop for piezoelectric transformer-based power converters

DEFF Research Database (Denmark)

Ekhtiari, Marzieh; Andersen, Thomas; Zhang, Zhe

2016-01-01

A new method is implemented in designing of self-oscillating loop for driving piezoelectric transformers. The implemented method is based on combining both analog and digital control systems. Digitized delay, or digitized phase shift through the self-oscillating loop results in a very precise...... frequency control and ensures an optimum operation of the piezoelectric transformer in terms of voltage gain and efficiency. In this work, additional time delay is implemented digitally for the first time through 16 bit digital-to-analog converter to the self-oscillating loop. Delay control setpoints...... updates at a rate of 417 kHz. This allows the control loop to dynamically follow frequency changes of the transformer in each resonant cycle. The operation principle behind self-oscillating is discussed in this paper. Moreover, experimental results are reported....

Digital signals processing using non-linear orthogonal transformation in frequency domain

Directory of Open Access Journals (Sweden)

Ivanichenko E.V.

2017-12-01

Full Text Available The rapid progress of computer technology in recent decades led to a wide introduction of methods of digital information processing practically in all fields of scientific research. In this case, among various applications of computing one of the most important places is occupied by digital processing systems signals (DSP that are used in data processing remote solution tasks of navigation of aerospace and marine objects, communications, radiophysics, digital optics and in a number of other applications. Digital Signal Processing (DSP is a dynamically developing an area that covers both technical and software tools. Related areas for digital signal processing are theory information, in particular, the theory of optimal signal reception and theory pattern recognition. In the first case, the main problem is signal extraction against a background of noise and interference of a different physical nature, and in the second - automatic recognition, i.e. classification and signal identification. In the digital processing of signals under a signal, we mean its mathematical description, i.e. a certain real function, containing information on the state or behavior of a physical system under an event that can be defined on a continuous or discrete space of time variation or spatial coordinates. In the broad sense, DSP systems mean a complex algorithmic, hardware and software. As a rule, systems contain specialized technical means of preliminary (or primary signal processing and special technical means for secondary processing of signals. Means of pretreatment are designed to process the original signals observed in general case against a background of random noise and interference of a different physical nature and represented in the form of discrete digital samples, for the purpose of detecting and selection (selection of the useful signal and evaluation characteristics of the detected signal. A new method of digital signal processing in the frequency

Transforming care in nursing: a concept analysis.

Science.gov (United States)

Vázquez-Calatayud, Mónica; Oroviogoicoechea, Cristina; Saracibar, Maribel; Pumar-Méndez, María J

2017-04-01

Although the concept of 'Transforming care' is promising for improving health care, there is no consensus in the field as to its definition. The aim of this concept analysis is to develop a deeper understanding of the term 'Transforming care' within the nursing discipline, in order to facilitate its comprehension, implementation, and evaluation. We performed a comprehensive literature review on electronic databases such as Medline (PubMed), Cinahl (Ebsco), Cochrane Library, PsycINFO (Ovid), Web of Science, Wiley-Blackwell, ScienceDirect, and SpringerLink and used Walker and Avant's approach to analyse the concept. From the 20 studies selected for this analysis, 3 main attributes of 'Transforming care' were identified: patient-centredness, evidence-based change, and transformational leadership driven. We suggest an operational definition to facilitate the implementation of the concept in practice. Furthermore, we propose that implementation is guided by the following key ideas: (1) fostering a culture of continuous improvement; (2) encouraging bottom-up initiatives; (3) promoting patient-centred care; and (4) using transformational leadership. Lastly, the evaluation of 'Transforming care' initiatives should assess care processes and professionals' and patients' outcomes.

Neoplastic transformation of hamster embryo cells irradiated in utero and assayed in vitro

International Nuclear Information System (INIS)

Borek, C.; Pain, C.; Mason, H.

1977-01-01

It is stated that induction of neoplastic transformation in vitro by x-rays and neutrons has been reported, and the authors had previously found that transformation by x-rays could be detected at doses as low as 1 R and the rate of transformation increased with dose, reaching a peak of 1% between 150 and 300 R. This frequency of neoplastic transformation in vitro is much higher than the frequency of radiation induced tumors observed after exposing animals to similar doses of radiation. Studies are here reported showing that malignant transformed cells can be obtained from embryos irradiated in utero and assayed in vitro, and that the frequency of transformation is at least tenfold lower than when the irradiations are performed in vitro, and thus closer to the incidence in animals. Hamster embryo cells were used for the studies. Questions that arise are as follows: does the host mediate in modulating transformation by radiation; is there a repair of transforming events before they can be expressed; and how significant is the state of cells during irradiation in determining the rate of transformation. It is known from in vitro studies that cell replication is required for fixation of the transformation. With the in vitro technique cells are seeded as single cells with ample opportunity to divide. In addition they are not in contact with one another, and constitute a mixture of cell types from many tissues. In utero the situation is quite different; the embryonic cells are irradiated as tissues where there is cell to cell contact in tissue-specific arrangements, and where the rate of cell replication varies with the tissue. It remains to be seen which of these factors, if any, is responsible for the lowered yield of transformed cells characteristic of in utero as opposed to in vitro irradiation. (U.K.)

Wavelet transforms as solutions of partial differential equations

Energy Technology Data Exchange (ETDEWEB)

Zweig, G.

1997-10-01

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Wavelet transforms are useful in representing transients whose time and frequency structure reflect the dynamics of an underlying physical system. Speech sound, pressure in turbulent fluid flow, or engine sound in automobiles are excellent candidates for wavelet analysis. This project focused on (1) methods for choosing the parent wavelet for a continuous wavelet transform in pattern recognition applications and (2) the more efficient computation of continuous wavelet transforms by understanding the relationship between discrete wavelet transforms and discretized continuous wavelet transforms. The most interesting result of this research is the finding that the generalized wave equation, on which the continuous wavelet transform is based, can be used to understand phenomena that relate to the process of hearing.

The Impact of Increasing Fire Frequency on Forest Transformations in the Zabaikal Region, Southern Siberia

Science.gov (United States)

Conard, S. G.; Kukavskaya, E. A.; Buryak, L. V.; Shvetsov, E.; Kalenskaya, O. P.; Zhila, S.

2017-12-01

The Zabaikal region of southern Siberia is characterized by some of the highest fire activity in Russia. There has been a significant increase of fire frequency and burned area in the region over the last two decades due to a combination of high anthropogenic pressure, decreased funding to the forestry sector, and increased fire danger, which was associated with higher frequency and intensity of extreme weather events. Central and southern parts of the Zabaikal region where population density is higher and road network is relatively more developed are the most disturbed by fires. Larch stands cover the largest proportion of fire-disturbed lands in the region, while the less common pine and birch stands are characterized by higher fire frequency. About 13% (3.9 M ha) of the total forest area in the Zabaikal region was burned more than once in the 20 years from 1996 to 2015, with many sites burned multiple times. Repeat disturbances led to inadequate tree regeneration on all but the moistest sites. Pine stands on dry soils, which are common in the forest-steppe zone, were the most vulnerable. After repeat burns and over large burned sites we observed transformation of the forests to steppe ecosystems. The most likely causes of insufficient forest regeneration are soil overheating, dominance of tall grasses, and lack of nearby seed sources. Extensive tree plantations have potential to mitigate negative fire impacts; however, due to high fire hazard in the recent decade about half of the plantation area has been burned. Changes in the SWVI index were used to assess postfire reforestation based on a combination of satellite and field data. In the southwestern part of the Zabaikal region, we estimated that reforestation had been hampered over 11% of the forest land area. Regional climate models project increasing temperatures and decreasing precipitation across Siberia by the end of the 21st century, with changes in the Zabaikal region projected to be more than twice the

Relationship between wingbeat frequency and resonant frequency of the wing in insects

International Nuclear Information System (INIS)

Ha, Ngoc San; Truong, Quang Tri; Goo, Nam Seo; Park, Hoon Cheol

2013-01-01

In this study, we experimentally studied the relationship between wingbeat frequency and resonant frequency of 30 individuals of eight insect species from five orders: Odonata (Sympetrum flaveolum), Lepidoptera (Pieris rapae, Plusia gamma and Ochlodes), Hymenoptera (Xylocopa pubescens and Bombus rupestric), Hemiptera (Tibicen linnei) and Coleoptera (Allomyrina dichotoma). The wingbeat frequency of free-flying insects was measured using a high-speed camera while the natural frequency was determined using a laser displacement sensor along with a Bruel and Kjaer fast Fourier transform analyzer based on the base excitation method. The results showed that the wingbeat frequency was related to body mass (m) and forewing area (A f ), following the proportionality f ∼ m 1/2 /A f , while the natural frequency was significantly correlated with area density (f 0  ∼ m w /A f , m w is the wing mass). In addition, from the comparison of wingbeat frequency to natural frequency, the ratio between wingbeat frequency and natural frequency was found to be, in general, between 0.13 and 0.67 for the insects flapping at a lower wingbeat frequency (less than 100 Hz) and higher than 1.22 for the insects flapping at a higher wingbeat frequency (higher than 100 Hz). These results suggest that wingbeat frequency does not have a strong relation with resonance frequency: in other words, insects have not been evolved sufficiently to flap at their wings' structural resonant frequency. This contradicts the general conclusion of other reports-–that insects flap at their wings' resonant frequency to take advantage of passive deformation to save energy. (paper)

Phase-modulated radio over fiber multimode links.

Science.gov (United States)

Gasulla, Ivana; Capmany, José

2012-05-21

We present the first experimental demonstration of a phase-modulated MMF link implementing high-frequency digital transmission in a cost-effective solution based on direct detection. Successful subcarrier transmission of QPSK, 16-QAM and 64-QAM data channels for bit rates up to 120 Mb/s through a 5 km MMF link is achieved over the microwave region comprised between 6 and 20 GHz. The overall capacity of the proposed approach can be further increased by properly accommodating more passband channels in the operative frequency range determined by the phase-to-intensity conversion process provided by the dispersive nature of the optical fiber. In this sense, our results show the possibility of achieving an aggregate bit rate per length product of 144 Gb/s · km and confirm, in consequence, the possibility of broadband phase-modulated radio over fiber transmission through MMF links suitable for multichannel SCM signal distribution.

Discrete linear canonical transforms based on dilated Hermite functions.

Science.gov (United States)

Pei, Soo-Chang; Lai, Yun-Chiu

2011-08-01

Linear canonical transform (LCT) is very useful and powerful in signal processing and optics. In this paper, discrete LCT (DLCT) is proposed to approximate LCT by utilizing the discrete dilated Hermite functions. The Wigner distribution function is also used to investigate DLCT performances in the time-frequency domain. Compared with the existing digital computation of LCT, our proposed DLCT possess additivity and reversibility properties with no oversampling involved. In addition, the length of input/output signals will not be changed before and after the DLCT transformations, which is consistent with the time-frequency area-preserving nature of LCT; meanwhile, the proposed DLCT has very good approximation of continuous LCT.

Investigation, development and verification of printed circuit board embedded air-core solenoid transformers

DEFF Research Database (Denmark)

Mønster, Jakob Døllner; Madsen, Mickey Pierre; Pedersen, Jeppe Arnsdorf

2015-01-01

A new printed circuit board embedded air-core transformer/coupled inductor is proposed and presented. The transformer is intended for use in power converter applications operating at very high frequency between 30 MHz to 300 MHz. The transformer is based on two or more solenoid structures...

Ultra-stable long distance optical frequency distribution using the Internet fiber network.

Science.gov (United States)

Lopez, Olivier; Haboucha, Adil; Chanteau, Bruno; Chardonnet, Christian; Amy-Klein, Anne; Santarelli, Giorgio

2012-10-08

We report an optical link of 540 km for ultrastable frequency distribution over the Internet fiber network. The stable frequency optical signal is processed enabling uninterrupted propagation on both directions. The robustness and the performance of the link are enhanced by a cost effective fully automated optoelectronic station. This device is able to coherently regenerate the return optical signal with a heterodyne optical phase locking of a low noise laser diode. Moreover the incoming signal polarization variation are tracked and processed in order to maintain beat note amplitudes within the operation range. Stable fibered optical interferometer enables optical detection of the link round trip phase signal. The phase-noise compensated link shows a fractional frequency instability in 10 Hz bandwidth of 5 × 10(-15) at one second measurement time and 2 × 10(-19) at 30,000 s. This work is a significant step towards a sustainable wide area ultrastable optical frequency distribution and comparison network.

Performance prediction of a synchronization link for distributed aerospace wireless systems.

Science.gov (United States)

Wang, Wen-Qin; Shao, Huaizong

2013-01-01

For reasons of stealth and other operational advantages, distributed aerospace wireless systems have received much attention in recent years. In a distributed aerospace wireless system, since the transmitter and receiver placed on separated platforms which use independent master oscillators, there is no cancellation of low-frequency phase noise as in the monostatic cases. Thus, high accurate time and frequency synchronization techniques are required for distributed wireless systems. The use of a dedicated synchronization link to quantify and compensate oscillator frequency instability is investigated in this paper. With the mathematical statistical models of phase noise, closed-form analytic expressions for the synchronization link performance are derived. The possible error contributions including oscillator, phase-locked loop, and receiver noise are quantified. The link synchronization performance is predicted by utilizing the knowledge of the statistical models, system error contributions, and sampling considerations. Simulation results show that effective synchronization error compensation can be achieved by using this dedicated synchronization link.

Application of methylation in improving plasmid transformation into Helicobacter pylori.

Science.gov (United States)

Zhao, Huilin; Xu, Linlin; Rong, Qianyu; Xu, Zheng; Ding, Yunfei; Zhang, Ying; Wu, Yulong; Li, Boqing; Ji, Xiaofei

2018-05-23

Helicobacter pylori is an important gastrointestinal pathogen. Its strains possess different levels of powerful restriction modification systems, which are significant barriers to genetic tools used for studying the role of functional genes in its pathogenesis. Methylating vectors in vitro was reported as an alternative to overcome this barrier in several bacteria. In this study we used two H. pylori-E. coli shuttle plasmids and several single/double-crossover homologous recombination gene-targeting plasmids, to test the role of methylation in H. pylori transformation. According to our results, transformants could be obtained only after shuttle plasmids were methylated before transformation. It is helpful in gene complementation and over-expression although at a low frequency. The frequency of gene-targeting transformation was also increased after methylation, especially for the single-crossover recombination plasmids, the transformants of which could only be obtained after methylation. For the double-crossover recombination targeting plasmids, the initial yield of transformants was 0.3-0.8 × 10 2 CFUs per microgram plasmid DNA. With the help of methylation, the yield was increased to 0.4-1.3 × 10 2 CFUs per microgram plasmid DNA. These results suggest that in vitro methylation can improve H. pylori transformation by different plasmids, which will benefit the pathogenic mechanism research. Copyright © 2018. Published by Elsevier B.V.

Helically linked mirror arrangement

International Nuclear Information System (INIS)

Ranjan, P.

1986-08-01

A scheme is described for helical linking of mirror sections, which endeavors to combine the better features of toroidal and mirror devices by eliminating the longitudinal loss of mirror machines, having moderately high average β and steady state operation. This scheme is aimed at a device, with closed magnetic surfaces having rotational transform for equilibrium, one or more axisymmetric straight sections for reduced radial loss, a simple geometrical axis for the links and an overall positive magnetic well depth for stability. We start by describing several other attempts at linking of mirror sections, made both in the past and the present. Then a description of our helically linked mirror scheme is given. This example has three identical straight sections connected by three sections having helical geometric axes. A theoretical analysis of the magnetic field and single-particle orbits in them leads to the conclusion that most of the passing particles would be confined in the device and they would have orbits independent of pitch angle under certain conditions. Numerical results are presented, which agree well with the theoretical results as far as passing particle orbits are concerned

Bacterial natural transformation by highly fragmented and damaged DNA

DEFF Research Database (Denmark)

Overballe-Petersen, Søren; Harms, Klaus; Orlando, Ludovic Antoine Alexandre

2013-01-01

for microbes, but not as potential substrate for bacterial evolution. Here, we show that fragmented DNA molecules (≥20 bp) that additionally may contain abasic sites, cross-links, or miscoding lesions are acquired by the environmental bacterium Acinetobacter baylyi through natural transformation. With uptake......DNA molecules are continuously released through decomposition of organic matter and are ubiquitous in most environments. Such DNA becomes fragmented and damaged (often DNA is recognized as nutrient source...... of DNA from a 43,000-y-old woolly mammoth bone, we further demonstrate that such natural transformation events include ancient DNA molecules. We find that the DNA recombination is RecA recombinase independent and is directly linked to DNA replication. We show that the adjacent nucleotide variations...

Efficient Plastid Transformation in Arabidopsis.

Science.gov (United States)

Yu, Qiguo; Lutz, Kerry Ann; Maliga, Pal

2017-09-01

Plastid transformation is routine in tobacco ( Nicotiana tabacum ) but 100-fold less frequent in Arabidopsis ( Arabidopsis thaliana ), preventing its use in plastid biology. A recent study revealed that null mutations in ACC2 , encoding a plastid-targeted acetyl-coenzyme A carboxylase, cause hypersensitivity to spectinomycin. We hypothesized that plastid transformation efficiency should increase in the acc2 background, because when ACC2 is absent, fatty acid biosynthesis becomes dependent on translation of the plastid-encoded ACC β-carboxylase subunit. We bombarded ACC2 -defective Arabidopsis leaves with a vector carrying a selectable spectinomycin resistance ( aadA ) gene and gfp , encoding the green fluorescence protein GFP. Spectinomycin-resistant clones were identified as green cell clusters on a spectinomycin medium. Plastid transformation was confirmed by GFP accumulation from the second open reading frame of a polycistronic messenger RNA, which would not be translated in the cytoplasm. We obtained one to two plastid transformation events per bombarded sample in spectinomycin-hypersensitive Slavice and Columbia acc2 knockout backgrounds, an approximately 100-fold enhanced plastid transformation frequency. Slavice and Columbia are accessions in which plant regeneration is uncharacterized or difficult to obtain. A practical system for Arabidopsis plastid transformation will be obtained by creating an ACC2 null background in a regenerable Arabidopsis accession. The recognition that the duplicated ACCase in Arabidopsis is an impediment to plastid transformation provides a rational template to implement plastid transformation in related recalcitrant crops. © 2017 American Society of Plant Biologists. All Rights Reserved.

Analysis and design of a series resonant converter with wide operating range and minimized transformer ratings

DEFF Research Database (Denmark)

Dincan, Catalin Gabriel; Kjær, Philip Carne; Chen, Yu-Hsing

2017-01-01

) allows the transformer design to be determined by peak load and maximum switching frequency, while still avoiding over-excitation at reduced load and reduced excitation frequency. This promises transformer size reduction of more than 50%, while losses are kept below 1% from zero to nominal power. A step...

Epileptic Seizure Detection based on Wavelet Transform Statistics Map and EMD Method for Hilbert-Huang Spectral Analyzing in Gamma Frequency Band of EEG Signals

Directory of Open Access Journals (Sweden)

Morteza Behnam

2015-08-01

Full Text Available Seizure detection using brain signal (EEG analysis is the important clinical methods in drug therapy and the decisions before brain surgery. In this paper, after signal conditioning using suitable filtering, the Gamma frequency band has been extracted and the other brain rhythms, ambient noises and the other bio-signal are canceled. Then, the wavelet transform of brain signal and the map of wavelet transform in multi levels are computed. By dividing the color map to different epochs, the histogram of each sub-image is obtained and the statistics of it based on statistical momentums and Negentropy values are calculated. Statistical feature vector using Principle Component Analysis (PCA is reduced to one dimension. By EMD algorithm and sifting procedure for analyzing the data by Intrinsic Mode Function (IMF and computing the residues of brain signal using spectrum of Hilbert transform and Hilbert – Huang spectrum forming, one spatial feature based on the Euclidian distance for signal classification is obtained. By K-Nearest Neighbor (KNN classifier and by considering the optimal neighbor parameter, EEG signals are classified in two classes, seizure and non-seizure signal, with the rate of accuracy 76.54% and with variance of error 0.3685 in the different tests.

Cell-to-cell transformation in Escherichia coli: a novel type of natural transformation involving cell-derived DNA and a putative promoting pheromone.

Directory of Open Access Journals (Sweden)

Rika Etchuuya

Full Text Available Escherichia coli is not assumed to be naturally transformable. However, several recent reports have shown that E. coli can express modest genetic competence in certain conditions that may arise in its environment. We have shown previously that spontaneous lateral transfer of non-conjugative plasmids occurs in a colony biofilm of mixed E. coli strains (a set of a donor strain harbouring a plasmid and a plasmid-free recipient strain. In this study, with high-frequency combinations of strains and a plasmid, we constructed the same lateral plasmid transfer system in liquid culture. Using this system, we demonstrated that this lateral plasmid transfer was DNase-sensitive, indicating that it is a kind of transformation in which DNase-accessible extracellular naked DNA is essential. However, this transformation did not occur with purified plasmid DNA and required a direct supply of plasmid from co-existing donor cells. Based on this feature, we have termed this transformation type as 'cell-to-cell transformation'. Analyses using medium conditioned with the high-frequency strain revealed that this strain released a certain factor(s that promoted cell-to-cell transformation and arrested growth of the other strains. This factor is heat-labile and protease-sensitive, and its roughly estimated molecular mass was between ∼9 kDa and ∼30 kDa, indicating that it is a polypeptide factor. Interestingly, this factor was effective even when the conditioned medium was diluted 10(-5-10(-6, suggesting that it acts like a pheromone with high bioactivity. Based on these results, we propose that cell-to-cell transformation is a novel natural transformation mechanism in E. coli that requires cell-derived DNA and is promoted by a peptide pheromone. This is the first evidence that suggests the existence of a peptide pheromone-regulated transformation mechanism in E. coli and in Gram-negative bacteria.

Analytical investigations of the Sumudu transform and applications to integral production equations

Directory of Open Access Journals (Sweden)

Belgacem Fethi Bin Muhammed

2003-01-01

Full Text Available The Sumudu transform, whose fundamental properties are presented in this paper, is little known and not widely used. However, being the theoretical dual to the Laplace transform, the Sumudu transform rivals it in problem solving. Having scale and unit-preserving properties, the Sumudu transform may be used to solve problems without resorting to a new frequency domain. Here, we use it to solve an integral production-depreciation problem.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 109

Science.gov (United States)

Valdez, A.

2000-01-01

This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 109, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

Adaptive synchrosqueezing based on a quilted short-time Fourier transform

Science.gov (United States)

Berrian, Alexander; Saito, Naoki

2017-08-01

In recent years, the synchrosqueezing transform (SST) has gained popularity as a method for the analysis of signals that can be broken down into multiple components determined by instantaneous amplitudes and phases. One such version of SST, based on the short-time Fourier transform (STFT), enables the sharpening of instantaneous frequency (IF) information derived from the STFT, as well as the separation of amplitude-phase components corresponding to distinct IF curves. However, this SST is limited by the time-frequency resolution of the underlying window function, and may not resolve signals exhibiting diverse time-frequency behaviors with sufficient accuracy. In this work, we develop a framework for an SST based on a "quilted" short-time Fourier transform (SST-QSTFT), which allows adaptation to signal behavior in separate time-frequency regions through the use of multiple windows. This motivates us to introduce a discrete reassignment frequency formula based on a finite difference of the phase spectrum, ensuring computational accuracy for a wider variety of windows. We develop a theoretical framework for the SST-QSTFT in both the continuous and the discrete settings, and describe an algorithm for the automatic selection of optimal windows depending on the region of interest. Using synthetic data, we demonstrate the superior numerical performance of SST-QSTFT relative to other SST methods in a noisy context. Finally, we apply SST-QSTFT to audio recordings of animal calls to demonstrate the potential of our method for the analysis of real bioacoustic signals.

Ring-dot-shaped multilayer piezoelectric step-down transformers using PZT-based ceramics

International Nuclear Information System (INIS)

Kim, Insung; Joo, Hyeonkyu; Song, Jaesung; Jeong, Soonjong; Kim, Minsoo

2010-01-01

In this study, multilayer piezo stack transformers for switching mode power supply (SMPS) application were manufactured using 0.01Pb(Ni 1/3 Nb 2/3 )O 3 - 0.08Pb(Mn 1/3 Nb 2/3 )O 3 - 0.91Pb(Zr 0.505 Ti 0.495 )O 3 (PNN-PMN-PZT) ceramics. The voltage ratio of a multilayer piezo stack transformer showed a maximum at the resonance frequency of the input and then increased with increasing load resistance. The efficiency of the multilayer piezo stack transformer showed its highest value at around the matching load. The output power increased with increasing input voltage. The temperature of the multilayer piezo stack transformer increased with increasing output power and load resistance. The manufactured multilayer piezo stack transformer could be used up to 5 W at a resonance frequency of 70.25 kHz for SMPS application because the temperature rise from room temperature is believed to about 20 .deg. C and because the transformer is electrically stable. The newly-developed ring-dot-type step-down multilayer piezo stack transformer shows possible applications as SMPS for electronic power sources with excellent input-to-output properties.

Mapping the x-linked lymphoproliferative syndrome

International Nuclear Information System (INIS)

Skare, J.C.; Milunsky, A.; Byron, K.S.; Sullivan, J.L.

1987-01-01

The X-linked lymphoproliferative syndrome is triggered by Epstein-Barr virus infection and results in fatal mononucleosis, immunodeficiency, and lymphoproliferative disorders. This study shows that the mutation responsible for X-linked lymphoproliferative syndrome is genetically linked to a restriction fragment length polymorphism detected with the DXS42 probe (from Xq24-q27). The most likely recombination frequency between the loci is 4%, and the associated logarithm of the odds is 5.26. Haplotype analysis using flanking restriction fragment length polymorphism markers indicates that the locus for X-linked lymphoproliferative syndrome is distal to probe DXS42 but proximal to probe DXS99 (from Xq26-q27). It is now possible to predict which members of a family with X-linked lymphoproliferative syndrome are carrier females and to diagnose the syndrome prenatally

Mapping the x-linked lymphoproliferative syndrome

Energy Technology Data Exchange (ETDEWEB)

Skare, J.C.; Milunsky, A.; Byron, K.S.; Sullivan, J.L.

1987-04-01

The X-linked lymphoproliferative syndrome is triggered by Epstein-Barr virus infection and results in fatal mononucleosis, immunodeficiency, and lymphoproliferative disorders. This study shows that the mutation responsible for X-linked lymphoproliferative syndrome is genetically linked to a restriction fragment length polymorphism detected with the DXS42 probe (from Xq24-q27). The most likely recombination frequency between the loci is 4%, and the associated logarithm of the odds is 5.26. Haplotype analysis using flanking restriction fragment length polymorphism markers indicates that the locus for X-linked lymphoproliferative syndrome is distal to probe DXS42 but proximal to probe DXS99 (from Xq26-q27). It is now possible to predict which members of a family with X-linked lymphoproliferative syndrome are carrier females and to diagnose the syndrome prenatally.

The social structural foundations of adaptation and transformation in social-ecological systems

Directory of Open Access Journals (Sweden)

Michele L. Barnes

2017-12-01

Full Text Available Social networks are frequently cited as vital for facilitating successful adaptation and transformation in linked social-ecological systems to overcome pressing resource management challenges. Yet confusion remains over the precise nature of adaptation vs. transformation and the specific social network structures that facilitate these processes. Here, we adopt a network perspective to theorize a continuum of structural capacities in social-ecological systems that set the stage for effective adaptation and transformation. We begin by drawing on the resilience literature and the multilayered action situation to link processes of change in social-ecological systems to decision making across multiple layers of rules underpinning societal organization. We then present a framework that hypothesizes seven specific social-ecological network configurations that lay the structural foundation necessary for facilitating adaptation and transformation, given the type and magnitude of human action required. A key contribution of the framework is explicit consideration of how social networks relate to ecological structures and the particular environmental problem at hand. Of the seven configurations identified, three are linked to capacities conducive to adaptation and three to transformation, and one is hypothesized to be important for facilitating both processes. We discuss how our theoretical framework can be applied in practice by highlighting existing empirical examples from related environmental governance contexts. Further extension of our hypotheses, particularly as more data become available, can ultimately help guide the design of institutional arrangements to be more effective at dealing with change.

A new nonsyndromic X-linked sensorineural hearing impairment linked to Xp21.2

Energy Technology Data Exchange (ETDEWEB)

Lalwani, A.K.; Brister, J.R.; Fex, J.; Grundfast, K.M.; Pikus, A.T.; Ploplis, B.; San Agustin, T.; Skarka, H.; Wilcox, E.R. [National Institutes of Health, Bethesda, MD (United States)

1994-10-01

X-linked deafness is a rare cause of hereditary hearing impairment. We have identified a family with X-linked dominant sensorineural hearing impairment, characterized by incomplete penetrance and variable expressivity in carrier females, that is linked to the Xp21.2, which contains the Duchenne muscular dystrophy (DMD) locus. The auditory impairment in affected males was congenital, bilateral, profound, sensorineural, affecting all frequencies, and without evidence of radiographic abnormality of the temporal bone. Adult carrier females manifested bilateral, mild-to-moderate high-frequency sensorineural hearing impairment of delayed onset during adulthood. Eighteen commercially available polymorphic markers from the X chromosome, generating a 10-15-cM map, were initially used for identification of a candidate region. DXS997, located within the DMD gene, generated a two-point LOD score of 2.91 at {theta} = 0, with every carrier mother heterozygous at this locus. Recombination events at DXS992 (located within the DMD locus, 3{prime} to exon 50 of the dystrophin gene) and at DXS1068 (5{prime} to the brain promoter of the dystrophin gene) were observed. No recombination events were noted with the following markers within the DMD locus: 5{prime}DYS II, intron 44, DXS997, and intron 50. There was no clinical evidence of Duchenne or Becker muscular dystrophy in any family member. It is likely that this family represents a new locus on the X chromosome, which when mutated results in nonsyndromic sensorineural hearing loss and is distinct from the heterogeneous group of X-linked hearing losses that have been previously described. 57 refs., 6 figs., 1 tab.

Zero-guard-interval coherent optical OFDM with overlapped frequency-domain CD and PMD equalization.

Science.gov (United States)

Chen, Chen; Zhuge, Qunbi; Plant, David V

2011-04-11

This paper presents a new channel estimation/equalization algorithm for coherent OFDM (CO-OFDM) digital receivers, which enables the elimination of the cyclic prefix (CP) for OFDM transmission. We term this new system as the zero-guard-interval (ZGI)-CO-OFDM. ZGI-CO-OFDM employs an overlapped frequency-domain equalizer (OFDE) to compensate both chromatic dispersion (CD) and polarization mode dispersion (PMD) before the OFDM demodulation. Despite the zero CP overhead, ZGI-CO-OFDM demonstrates a superior PMD tolerance than the previous reduced-GI (RGI)-CO-OFDM, which is verified under several different PMD conditions. Additionally, ZGI-CO-OFDM can improve the channel estimation accuracy under high PMD conditions by using a larger intra-symbol frequency-averaging (ISFA) length as compared to RGI-CO-OFDM. ZGI-CO-OFDM also enables the use of ever smaller fast Fourier transform (FFT) sizes (i.e. OFDM. We show that ZGI-CO-OFDM requires reasonably small additional computation effort (~13.6%) compared to RGI-CO-OFDM for 112-Gb/s transmission over a 1600-km dispersion-uncompensated optical link. © 2011 Optical Society of America

High-frequency, high-intensity photoionization

Science.gov (United States)

Reiss, H. R.

1996-02-01

Two analytical methods for computing ionization by high-frequency fields are compared. Predicted ionization rates compare well, but energy predictions for the onset of ionization differ radically. The difference is shown to arise from the use of a transformation in one of the methods that alters the zero from which energy is measured. This alteration leads to an apparent energy threshold for ionization that can, especially in the stabilization regime, differ strongly from the laboratory measurement. It is concluded that channel closings in intense-field ionization can occur at high as well as low frequencies. It is also found that the stabilization phenomenon at high frequencies, very prominent for hydrogen, is absent in a short-range potential.

Selection of the wavelet function for the frequencies estimation; Seleccion de la funcion wavelet para la estimacion de frecuencias

Energy Technology Data Exchange (ETDEWEB)

Garcia R, A. [ININ, Carretera Mexico-Toluca S/N, 52750 La Marquesa, Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: ramador@nuclear.inin.mx

2007-07-01

At the moment the signals are used to diagnose the state of the systems, by means of the extraction of their more important characteristics such as the frequencies, tendencies, changes and temporary evolutions. This characteristics are detected by means of diverse analysis techniques, as Autoregressive methods, Fourier Transformation, Fourier transformation in short time, Wavelet transformation, among others. The present work uses the one Wavelet transformation because it allows to analyze stationary, quasi-stationary and transitory signals in the time-frequency plane. It also describes a methodology to select the scales and the Wavelet function to be applied the one Wavelet transformation with the objective of detecting to the dominant system frequencies. (Author)

Surface Fourier-transform lens using a metasurface

International Nuclear Information System (INIS)

Li, Yun Bo; Cai, Ben Geng; Cheng, Qiang; Cui, Tie Jun

2015-01-01

We propose a surface (or 2D) Fourier-transform lens using a gradient refractive index (GRIN) metasurface in the microwave band, which is composed of sub-wavelength quasi-periodical metallic patches on a grounded dielectric substrate. Such a metasurface supports the transverse magnetic (TM) modes of surface waves. To gradually change the size of textures, we obtain different surface refractive indices, which can be tailored to fit the required refractive-index profile of a surface Fourier-transform lens. According to the theory of spatial Fourier transformation, we make use of the proposed lens to realize surface plane-wave scanning under different feeding locations. The simulation and experimental results jointly confirm the validity of the surface Fourier-transform lens. The proposed method can also be extended to the terahertz frequency. (paper)

Extraction of microseismic waveforms characteristics prior to rock burst using Hilbert-Huang transform

Science.gov (United States)

Li, Xuelong; Li, Zhonghui; Wang, Enyuan; Feng, Junjun; Chen, Liang; Li, Nan; Kong, Xiangguo

2016-09-01

This study provides a new research idea concerning rock burst prediction. The characteristics of microseismic (MS) waveforms prior to and during the rock burst were studied through the Hilbert-Huang transform (HHT). In order to demonstrate the advantage of the MS features extraction based on HHT, the conventional analysis method (Fourier transform) was also used to make a comparison. The results show that HHT is simple and reliable, and could extract in-depth information about the characteristics of MS waveforms. About 10 days prior to the rock burst, the main frequency of MS waveforms transforms from the high-frequency to low-frequency. What's more, the waveforms energy also presents accumulation characteristic. Based on our study results, it can be concluded that the MS signals analysis through HHT could provide valuable information about the coal or rock deformation and fracture.

Source study of the Jan Mayen transform fault strike-slip earthquakes

Science.gov (United States)

Rodríguez-Pérez, Q.; Ottemöller, L.

2014-07-01

Seismic source parameters of oceanic transform zone earthquakes have been relatively poorly studied. Previous studies showed that this type of earthquakes has unique characteristics such as not only the relatively common occurrence of slow events with weak seismic radiation at high frequencies but also the occurrence of some events that have high apparent stress indicating strong high frequency radiation. We studied 5 strike-slip earthquakes in the Jan Mayen fracture zone with magnitudes in the range of 5.9 centroid time delay compared to other oceanic transform fault earthquakes.

Transformational leadership and innovative work behavior among nursing staff.

Science.gov (United States)

Masood, Mariam; Afsar, Bilal

2017-10-01

The importance of innovation within organizations has been demonstrated on numerous occasions, which has subsequently led to the identification of effective leadership as a potential catalyst. Most of us would acknowledge that effective leadership plays a pivotal role to engender innovativeness among nursing staff. Although research has identified some leadership styles to foster a nurse's innovative work behavior, a comprehensive model explaining the effect of transformational leadership on nurses' innovative work behavior is still unclear. This research built and tested a theoretical model linking transformational leadership and innovative work behavior via several intervening variables. Data were collected from 587 nurses and 164 doctors (nursing supervisors) through structured questionnaires from public sector hospitals in Pakistan. Results of the study indicated that, as anticipated, transformational leadership positively affected psychological empowerment of nurses, which in turn influenced both intrinsic motivation and knowledge sharing behavior. These latter two variables then had a positive influence on innovative work behavior. Empowerment role identity moderated the link between transformational leadership and psychological empowerment, whereas willingness to rely on leader (reliance-based trust) and willingness to share sensitive information with leader (disclosure-based trust) moderated the connection between knowledge sharing behavior and innovative work behavior. These results imply that transformational leadership through psychological empowerment, knowledge sharing, and intrinsic motivation fosters nurse's innovative work behavior. The results also show that the relationship between transformational leadership and innovative work behavior is stronger among nurses who frequently share their knowledge about best practices and mistakes with co-workers. © 2017 John Wiley & Sons Ltd.

Transformation (normalization) of slope gradient and surface curvatures, automated for statistical analyses from DEMs

Science.gov (United States)

Csillik, O.; Evans, I. S.; Drăguţ, L.

2015-03-01

Automated procedures are developed to alleviate long tails in frequency distributions of morphometric variables. They minimize the skewness of slope gradient frequency distributions, and modify the kurtosis of profile and plan curvature distributions toward that of the Gaussian (normal) model. Box-Cox (for slope) and arctangent (for curvature) transformations are tested on nine digital elevation models (DEMs) of varying origin and resolution, and different landscapes, and shown to be effective. Resulting histograms are illustrated and show considerable improvements over those for previously recommended slope transformations (sine, square root of sine, and logarithm of tangent). Unlike previous approaches, the proposed method evaluates the frequency distribution of slope gradient values in a given area and applies the most appropriate transform if required. Sensitivity of the arctangent transformation is tested, showing that Gaussian-kurtosis transformations are acceptable also in terms of histogram shape. Cube root transformations of curvatures produced bimodal histograms. The transforms are applicable to morphometric variables and many others with skewed or long-tailed distributions. By avoiding long tails and outliers, they permit parametric statistics such as correlation, regression and principal component analyses to be applied, with greater confidence that requirements for linearity, additivity and even scatter of residuals (constancy of error variance) are likely to be met. It is suggested that such transformations should be routinely applied in all parametric analyses of long-tailed variables. Our Box-Cox and curvature automated transformations are based on a Python script, implemented as an easy-to-use script tool in ArcGIS.

Application of multiple signal classification algorithm to frequency estimation in coherent dual-frequency lidar

Science.gov (United States)

Li, Ruixiao; Li, Kun; Zhao, Changming

2018-01-01

Coherent dual-frequency Lidar (CDFL) is a new development of Lidar which dramatically enhances the ability to decrease the influence of atmospheric interference by using dual-frequency laser to measure the range and velocity with high precision. Based on the nature of CDFL signals, we propose to apply the multiple signal classification (MUSIC) algorithm in place of the fast Fourier transform (FFT) to estimate the phase differences in dual-frequency Lidar. In the presence of Gaussian white noise, the simulation results show that the signal peaks are more evident when using MUSIC algorithm instead of FFT in condition of low signal-noise-ratio (SNR), which helps to improve the precision of detection on range and velocity, especially for the long distance measurement systems.

Secondary Droop for Frequency and Voltage Restoration in Microgrids

DEFF Research Database (Denmark)

Nutkani, Inam Ullah; Peng, Wang; Blaabjerg, Frede

2015-01-01

Droop based autonomous control offers several advantages such as communication independence, plug-n-play capability and enhanced reliability of the system. Despite these advantages, frequency and voltage of droop controlled microgrid varies with the load change which is one of the major drawback...... of the droop control. Presently, the frequency and voltage restoration in microgrid is achieved through secondary control using low bandwidth communication links. This paper presents secondary-droop based frequency and voltage restoration method which is fully autonomous and independent of communication links....... With the proposed method, the microgrid frequency and voltage can be restored back to nominal value without affecting the power sharing performance of the generation sources. The proposed scheme performance has been validated in simulation for several cases of active and reactive power load conditions....

Discrete Multiwavelet Critical-Sampling Transform-Based OFDM System over Rayleigh Fading Channels

Directory of Open Access Journals (Sweden)

Sameer A. Dawood

2015-01-01

Full Text Available Discrete multiwavelet critical-sampling transform (DMWCST has been proposed instead of fast Fourier transform (FFT in the realization of the orthogonal frequency division multiplexing (OFDM system. The proposed structure further reduces the level of interference and improves the bandwidth efficiency through the elimination of the cyclic prefix due to the good orthogonality and time-frequency localization properties of the multiwavelet transform. The proposed system was simulated using MATLAB to allow various parameters of the system to be varied and tested. The performance of DMWCST-based OFDM (DMWCST-OFDM was compared with that of the discrete wavelet transform-based OFDM (DWT-OFDM and the traditional FFT-based OFDM (FFT-OFDM over flat fading and frequency-selective fading channels. Results obtained indicate that the performance of the proposed DMWCST-OFDM system achieves significant improvement compared to those of DWT-OFDM and FFT-OFDM systems. DMWCST improves the performance of the OFDM system by a factor of 1.5–2.5 dB and 13–15.5 dB compared with the DWT and FFT, respectively. Therefore the proposed system offers higher data rate in wireless mobile communications.

Time–frequency analysis of nonstationary complex magneto-hydro-dynamics in fusion plasma signals using the Choi–Williams distribution

International Nuclear Information System (INIS)

Xu, L.Q.; Hu, L.Q.; Chen, K.Y.; Li, E.Z.

2013-01-01

Highlights: • Choi–Williams distribution yields excellent time–frequency resolution for discrete signal. • CWD method provides clear time–frequency pictures of EAST and HT-7 fast MHD events. • CWD method has advantages to wavelets transform scalogram and the short-time Fourier transform spectrogram. • We discuss about how to choose the windows and free parameter of CWD method. -- Abstract: The Choi–Williams distribution is applied to the time–frequency analysis of signals describing rapid magneto-hydro-dynamic (MHD) modes and events in tokamak plasmas. A comparison is made with Soft X-ray (SXR) signals as well as Mirnov signal that shows the advantages of the Choi–Williams distribution over both continuous wavelets transform scalogram and the short-time Fourier transform spectrogram. Examples of MHD activities in HT-7 and EAST tokamak are shown, namely the onset of coupling tearing modes, high frequency precursors of sawtooth, and low frequency MHD instabilities in edge localized mode (ELM) free in H mode discharge

Cannabis sativa L. genetically transformed root based culture via Agrobacterium rhizogenes

Directory of Open Access Journals (Sweden)

Farnoush Berahmand

2016-09-01

Full Text Available It is an increased interest in the therapeutic potential of Cannabis sativa L. (marijuana for treatment of multiple sclerosis and HIV neuropathy. Because of limitation in cultivation of this plant, an efficient hairy root induction system for Cannabis sativa L. was developed in the present study. Agrobacterium rhizogenes mediated transformation performed by two different co-cultivation mediums and four different bacterial strains including A4, ATCC15834, MSU440, and A13 (MAFF-02-10266. Genomic DNA from putative transgenic hairy root lines and the control root was extracted using a modified CTAB protocol. Molecular analysis of transformed root lines was confirmed by polymerase chain reaction using specific primers of the rolB gene. The transformation frequency by Murashige and Skoog co-cultivation medium resulting in hairy root induction frequencies of 42.3%, 46.3%, 68.6% and 39.3% by A4, ATCC15834, MSU440, and A13 strains, respectively. There was no significant difference between MS or ½ MS co-cultivation mediums.  This study established a reliable protocol for induction of hairy roots of C. sativa. The best A. rhisogenes strain was MSU440. It was observed no significant difference between MS and ½ MS co-cultivation mediums on transformation frequency.

High temperature co-axial winding transformers

Science.gov (United States)

Divan, Deepakraj M.; Novotny, Donald W.

1993-01-01

The analysis and design of co-axial winding transformers is presented. The design equations are derived and the different design approaches are discussed. One of the most important features of co-axial winding transformers is the fact that the leakage inductance is well controlled and can be made low. This is not the case in conventional winding transformers. In addition, the power density of co-axial winding transformers is higher than conventional ones. Hence, using co-axial winding transformers in a certain converter topology improves the power density of the converter. The design methodology used in meeting the proposed specifications of the co-axial winding transformer specifications are presented and discussed. The final transformer design was constructed in the lab. Co-axial winding transformers proved to be a good choice for high power density and high frequency applications. They have a more predictable performance compared with conventional transformers. In addition, the leakage inductance of the transformer can be controlled easily to suit a specific application. For space applications, one major concern is the extraction of heat from power apparatus to prevent excessive heating and hence damaging of these units. Because of the vacuum environment, the only way to extract heat is by using a cold plate. One advantage of co-axial winding transformers is that the surface area available to extract heat from is very large compared to conventional transformers. This stems from the unique structure of the co-axial transformer where the whole core surface area is exposed and can be utilized for cooling effectively. This is a crucial issue here since most of the losses are core losses.

Fourier transform of delayed fluorescence as an indicator of herbicide concentration.

Science.gov (United States)

Guo, Ya; Tan, Jinglu

2014-12-21

It is well known that delayed fluorescence (DF) from Photosystem II (PSII) of plant leaves can be potentially used to sense herbicide pollution and evaluate the effect of herbicides on plant leaves. The research of using DF as a measure of herbicides in the literature was mainly conducted in time domain and qualitative correlation was often obtained. Fourier transform is often used to analyze signals. Viewing DF signal in frequency domain through Fourier transform may allow separation of signal components and provide a quantitative method for sensing herbicides. However, there is a lack of an attempt to use Fourier transform of DF as an indicator of herbicide. In this work, the relationship between the Fourier transform of DF and herbicide concentration was theoretically modelled and analyzed, which immediately yielded a quantitative method to measure herbicide concentration in frequency domain. Experiments were performed to validate the developed method. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Study of Frequency Mixing Approaches for Eddy Current Testing of Steam Generator Tubes

International Nuclear Information System (INIS)

Jung, Hee Jun; Song, Sung Jin; Kim, Chang Hwan; Kim, Dae Kwang

2009-01-01

The multifrequency eddy current testing(ECT) have been proposed various frequency mixing algorithms. In this study, we compare these approaches to frequency mixing of ECT signals from steam generator tubes; time-domain optimization, discrete cosine transform-domain optimization. Specifically, in this study, two different frequency mixing algorithms, a time-domain optimization method and a discrete cosine transform(DCT) optimization method, are investigated using the experimental signals captured from the ASME standard tube. The DCT domain optimization method is computationally fast but produces larger amount of residue.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 108 2

Science.gov (United States)

Valdez, A.

2000-01-01

This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1 SIN 108, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

Applicability and conception of the 1471 serial link module

International Nuclear Information System (INIS)

Weidhase, F.

1978-01-01

The 1471 link module developed at the Technical University Dresden is described. The main features are fast data transfer, reliability concerning perturbing effects, seperation of transmitter and receiver self-acting synchronization, completely insulated link modules, high common-mode rejection, self-checking, variable bit repetition frequency, and small demands concerning the transmission cable. Applicabilities are given and a comparison with known link modules is made

UV stimulation of DNA-mediated transformation of human cells

International Nuclear Information System (INIS)

van Duin, M.; Westerveld, A.; Hoeijmakers, J.H.

1985-01-01

Irradiation of dominant marker DNA with UV light (150 to 1,000 J/m2) was found to stimulate the transformation of human cells by this marker from two- to more than fourfold. This phenomenon is also displayed by xeroderma pigmentosum cells, which are deficient in the excision repair of UV-induced pyrimidine dimers in the DNA. Also, exposure to UV of the transfected (xeroderma pigmentosum) cells enhanced the transfection efficiency. Removal of the pyrimidine dimers from the DNA by photoreactivating enzyme before transfection completely abolished the stimulatory effect, indicating that dimer lesions are mainly responsible for the observed enhancement. A similar stimulation of the transformation efficiency is exerted by 2-acetoxy-2-acetylaminofluorene modification of the DNA. These findings suggest that lesions which are targets for the excision repair pathway induce the increase in transformation frequency. The stimulation was found to be independent of sequence homology between the irradiated DNA and the host chromosomal DNA. Therefore, the increase of the transformation frequency is not caused by a mechanism inducing homologous recombination between these two DNAs. UV treatment of DNA before transfection did not have a significant effect on the amount of DNA integrated into the xeroderma pigmentosum genome

Emotional Reframing as a Mediator of the Relationships between Transformational School Leadership and Teachers' Motivation and Commitment

Science.gov (United States)

Berkovich, Izhak; Eyal, Ori

2017-01-01

Purpose: Empirical evidence links transformational school leadership to teachers' autonomous motivation and affective organizational commitment. Little empirical research, however, has focused on the emotional mechanisms behind these relations. Following the argument in the literature that transformational leadership can transform followers'…

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A2, S/N 108, 08

Science.gov (United States)

Valdez, A.

2000-01-01

This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A2, S/N 108, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

Discrete Fourier and wavelet transforms an introduction through linear algebra with applications to signal processing

CERN Document Server

Goodman, Roe W

2016-01-01

This textbook for undergraduate mathematics, science, and engineering students introduces the theory and applications of discrete Fourier and wavelet transforms using elementary linear algebra, without assuming prior knowledge of signal processing or advanced analysis.It explains how to use the Fourier matrix to extract frequency information from a digital signal and how to use circulant matrices to emphasize selected frequency ranges. It introduces discrete wavelet transforms for digital signals through the lifting method and illustrates through examples and computer explorations how these transforms are used in signal and image processing. Then the general theory of discrete wavelet transforms is developed via the matrix algebra of two-channel filter banks. Finally, wavelet transforms for analog signals are constructed based on filter bank results already presented, and the mathematical framework of multiresolution analysis is examined.

Power/response spectrum transformations in equipment qualification

International Nuclear Information System (INIS)

Unruh, J.F.; Kana, D.D.

1985-01-01

Since its introduction a few years ago the use of the power/response spectrum transformation has gained considerable interest and acceptance, and a number of new applications of the transformation have been developed in the equipment qualification area. A brief review of the power/response spectrum transformation is given with a discussion of the input/output relationships for linear systems required for elevated power spectrum generation. Frequency content of earthquakelike signals is discussed with emphasis on the resolution given by the PSD. The problem of excessive ZPA due to inconsistent spectra enveloping and mechanical nonlinearities is also discussed. The PSD/RS transformation is applied to the problems of combining various dynamic load events, developing bounding spectra, and developing damping consistent test spectra. Development of elevated component spectra corrected for base overtest and generation from in-situ measurements is reviewed

STUDY REGARDING EFFICIENCY OF INDUCED GENETIC TRANSFORMATION IN BACILLUS LICHENIFORMIS WITH PLASMID DNA

Directory of Open Access Journals (Sweden)

VINTILĂ T.

2007-01-01

Full Text Available A strain of Bacillus licheniformis was subject to genetic transformation with plasmidvectors (pLC1 and pNC61, using electroporation technique, protoplasttransformation and bivalent cations (CaCl2 mediated transformation. In the case oftransformation by electroporation of Bacillus licheniformis B40, the highest numberof transformed colonies (3 were obtained only after a 1,79 KV electric shock, for 2,2milliseconds. Using this transformation technique we have obtained six kanamycinresistant transformants. The frequency of Bacillus licheniformis B40 protoplaststransformation using pLC1 and pNC61 plasmid vectors is approximately 10% (TF =10%. As a result of pLC1 plasmid integration in Bacillus licheniformis protoplasts,six kanamycin resistant transformants were obtained. The pNC61 plasmid, whichconfers trimethoprim resistance, does not integrate in receiver cells by protoplasttransformation. The direct genetic transformation in the presence of bivalent cations(CaCl2, mediated by pLC1 and pNC61 plasmid vectors, produce a lowtransformation frequency. Using this technique, we have obtained three trimethoprimresistant colonies and four kanamycin resistant colonies. The chemical way oftransformation is the only technique, which realizes the integration of pNC61 in B.licheniformis B40 cells.

Ring-dot-shaped multilayer piezoelectric step-down transformers using PZT-based ceramics

Energy Technology Data Exchange (ETDEWEB)

Kim, Insung; Joo, Hyeonkyu; Song, Jaesung; Jeong, Soonjong; Kim, Minsoo [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

2010-10-15

In this study, multilayer piezo stack transformers for switching mode power supply (SMPS) application were manufactured using 0.01Pb(Ni{sub 1/3}Nb{sub 2/3})O{sub 3} - 0.08Pb(Mn{sub 1/3}Nb{sub 2/3})O{sub 3} - 0.91Pb(Zr{sub 0.505}Ti{sub 0.495})O{sub 3} (PNN-PMN-PZT) ceramics. The voltage ratio of a multilayer piezo stack transformer showed a maximum at the resonance frequency of the input and then increased with increasing load resistance. The efficiency of the multilayer piezo stack transformer showed its highest value at around the matching load. The output power increased with increasing input voltage. The temperature of the multilayer piezo stack transformer increased with increasing output power and load resistance. The manufactured multilayer piezo stack transformer could be used up to 5 W at a resonance frequency of 70.25 kHz for SMPS application because the temperature rise from room temperature is believed to about 20 .deg. C and because the transformer is electrically stable. The newly-developed ring-dot-type step-down multilayer piezo stack transformer shows possible applications as SMPS for electronic power sources with excellent input-to-output properties.

One-shot Design of Radial Mode Piezoelectric Transformer for Magneticless Power Conversion

DEFF Research Database (Denmark)

Meyer, Kaspar Sinding; Andersen, Michael A. E.

2011-01-01

mathematical problem has been solved, that directly links wanted electrical specifications to the mechanical dimensions of a radial mode piezoelectric transformer. The novel outcome of this study is that the soft switching ability is directly linked to the ratio between the active volume of the primary......Piezoelectric Transformer based resonant power converters are an attractive alternative to magnetic power converters in applications requiring a power level currently less than 100W. Among the benefits are a power density up to 40W/cm3, a low profile, reduced radiated EMI and high system efficiency...... due to zero voltage switching commutation. The main criteria to take advantage of these benefits are, despite the fact that a PT is a piezoelectric capacitor, is optimization the transformer to behave inductively as a means to avoid excessive hard switching losses. With this objective, the inverse...

Semigroups of transformations with fixed sets | Honyam ...

African Journals Online (AJOL)

Click on the link to view the abstract. Keywords: Transformation semigroup, Green's relations, ideal, rank. Quaestiones Mathematicae 36(2013), 79-92. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.2989/16073606.2013.779958 · AJOL African ...

Similarity-transformed equation-of-motion vibrational coupled-cluster theory

Science.gov (United States)

Faucheaux, Jacob A.; Nooijen, Marcel; Hirata, So

2018-02-01

A similarity-transformed equation-of-motion vibrational coupled-cluster (STEOM-XVCC) method is introduced as a one-mode theory with an effective vibrational Hamiltonian, which is similarity transformed twice so that its lower-order operators are dressed with higher-order anharmonic effects. The first transformation uses an exponential excitation operator, defining the equation-of-motion vibrational coupled-cluster (EOM-XVCC) method, and the second uses an exponential excitation-deexcitation operator. From diagonalization of this doubly similarity-transformed Hamiltonian in the small one-mode excitation space, the method simultaneously computes accurate anharmonic vibrational frequencies of all fundamentals, which have unique significance in vibrational analyses. We establish a diagrammatic method of deriving the working equations of STEOM-XVCC and prove their connectedness and thus size-consistency as well as the exact equality of its frequencies with the corresponding roots of EOM-XVCC. We furthermore elucidate the similarities and differences between electronic and vibrational STEOM methods and between STEOM-XVCC and vibrational many-body Green's function theory based on the Dyson equation, which is also an anharmonic one-mode theory. The latter comparison inspires three approximate STEOM-XVCC methods utilizing the common approximations made in the Dyson equation: the diagonal approximation, a perturbative expansion of the Dyson self-energy, and the frequency-independent approximation. The STEOM-XVCC method including up to the simultaneous four-mode excitation operator in a quartic force field and its three approximate variants are formulated and implemented in computer codes with the aid of computer algebra, and they are applied to small test cases with varied degrees of anharmonicity.

On the moments of the Wigner distribution and the fractional Fourier transform

NARCIS (Netherlands)

Alieva, T.; Bastiaans, M.J.; Veen, J.P.

2000-01-01

A Fourier transformation maps a one-dimensional time signal into a one-dimensional frequency function, the signal spectrum. Although the Fourier transform provides the signal's spectral content, it fails to indicate the time location of the spectral components, which is important, for example, when

Detailed High Frequency Models of Various Winding Types in Power Transformers

DEFF Research Database (Denmark)

Pedersen, Kenneth; Lunow, Morten Erlandsson; Holbøll, Joachim

2005-01-01

Abstract--In this paper, techniques are described which demonstrate how a highly detailed internal transformer model can be obtained systematically with Matlab and how it can be prepared for subsequent transient analysis. The input of such a model will mainly be the description of the cross secti...... equivalent circuit. Finally a new circuit extraction technique is proposed for vector fitted impedance matrices for more efficient computation....

Rapid testing of pulse transformers

Science.gov (United States)

Grillo, J.

1980-01-01

Quality-control testing of pulse transformers is speeded up by method for determining rise time and droop. Instead of using oscilloscope and square-wave generator to measure these characteristics directly, method uses voltmeter and sine-wave generator to measure them indirectly in about one-tenth time. Droop and rise time are determined by measuring input/output voltage ratio at just four frequencies.

Research on Harmonic Characteristic of Electronic Current Transformer Based on the Rogowski Coil

Science.gov (United States)

Shen, Diqiu; Hu, Bei; Wang, Xufeng; Zhu, Mingdong; Wang, Liang; Lu, Wenxing

2017-05-01

The nonlinear load present in the power system will cause the distortion of AC sine wave and generate the harmonic, which havea severe impact on the accuracy of energy metering and reliability of relay protection. Tosatisfy the requirements of energy metering and relay protection for the new generation of intelligent substation, based on the working principle of Rogowski coil current transformer, mathematical model and transfer characteristics of Rogowski coil sensors were studied in this paper, and frequency response characteristics of Rogowski coil current transformer system were analysed. Finally, the frequency response characteristics of the Rogowski coil current transformer at 2 to 13 harmonics was simulated and experimented. Simulation and experiments show that Rogowski coil current transformer couldmeet 0.2 accuracy requirements of harmonic power measurement of power system, and measure the harmonic components of the grid reliably.

Performance Analysis of ARQ-Based RF-FSO Links

KAUST Repository

Makki, Behrooz

2017-02-22

We study the performance of hybrid radio-frequency (RF) and free-space optical (FSO) links using automatic repeat request (ARQ). We derive closed-form expressions for the throughput and outage probability with different channel models. We also evaluate the effect of adaptive power allocation between the ARQ retransmissions on the system performance. The results show that joint implementation of the RF and FSO links leads to substantial performance improvement, compared to the cases with only the RF or the FSO link.

Development of a Candida glabrata dominant nutritional transformation marker utilizing the Aspergillus nidulans acetamidase gene (amdS).

Science.gov (United States)

Fu, Jianmin; Blaylock, Morganne; Wickes, Cameron F; Welte, William; Mehrtash, Adrian; Wiederhold, Nathan; Wickes, Brian L

2016-05-01

The gene encoding Aspergillus nidulans acetamidase (amdS) was placed under control of Candida albicans ACT1 promoter and terminator sequences and then cloned into a plasmid containing C. glabrata ARS10,CEN8 or ARS10+CEN8 sequences. All plasmids transformed C. glabrata wild-type cells to acetamide+, with the ARS-only containing plasmid transforming cells at the highest frequencies (>1.0 × 10(4) transformants μg(-1)). Plasmids were rapidly lost under non-selective conditions with the frequency dependent on chromosomal element, thus recycling the acetamide- phenotype. The amdS plasmid was used to transform a set of clinical isolates resistant to a variety of antifungal drugs. All strains were successfully transformed to the acetamide+ phenotype at high frequency, confirming that this plasmid construct could be used as a simple dominant marker on virtually any strain. Gap repair experiments demonstrated that just as in Saccharomyces cerevisiae, gap repair functions efficiently inC. glabrata, suggesting that C. glabrata has numerous similarities toS. cerevisiae with regard to ease of molecular manipulation. The amdS system is inexpensive and efficient, and combined with existing C. glabrata plasmid elements, confers a high transformation frequency for C. glabrata with a phenotype that can be easily recycled. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

From CLARIN Component Metadata to Linked Open Data

NARCIS (Netherlands)

Durco, M.; Windhouwer, Menzo

2014-01-01

In the European CLARIN infrastructure a growing number of resources are described with Component Metadata. In this paper we describe a transformation to make this metadata available as linked data. After this first step it becomes possible to connect the CLARIN Component Metadata with other valuable

Two frequency ICRF operation on TFTR

International Nuclear Information System (INIS)

Rogers, J.H.; Majeski, R.; Wilson, J.R.; Hosea, J.C.; Schilling, G.; Stevens, J.; Phillips, C.K.

1993-01-01

Modifications have been made recently to allow two of the ICRF antennas (bays L and M) on TFTR to operate at either of two frequencies, 43 MHz or 64 MHz. This was accomplished by lengthening the resonant loops (2Λ at 43 MHz, 3Λ at 64 MHz) and replacing the conventional quarter wave impedance transformers with a tapered impedance design. The other two antennas (bays K and N) will operate at a fixed frequency, 43 MHz. The two frequency operation will allow a combination of 3 He-minority and H-minority heating at near full field on TFTR. The higher frequency, 64 MHz, may also be useful in direct electron heating and current drive experiments at lower toroidal fields. Models of the antenna, resonant loops and impedance matching system are presented

Study on the Thick-Walled Pipe Ultrasonic Signal Enhancement of Modified S-Transform and Singular Value Decomposition

Directory of Open Access Journals (Sweden)

Haichao Cai

2015-01-01

Full Text Available When detecting the ultrasonic flaw of thick-walled pipe, the flaw echo signals are often interrupted by scanning system frequency and background noise. In particular when the thick-walled pipe defect is small, echo signal amplitude is often drowned in noise signal and affects the extraction of defect signal and the position determination accuracy. This paper presents the modified S-transform domain singular value decomposition method for the analysis of ultrasonic flaw echo signals. By changing the scale rule of Gaussian window functions with S-transform to improve the time-frequency resolution. And the paper tries to decompose the singular value decomposition of time-frequency matrix after the S-transform to determine the singular entropy of effective echo signal and realize the adaptive filter. Experiments show that, using this method can not only remove high frequency noise but also remove the low frequency noise and improve the signal-to-noise ratio of echo signal.

Fourier transform resampling: Theory and application

International Nuclear Information System (INIS)

Hawkins, W.G.

1996-01-01

One of the most challenging problems in medical imaging is the development of reconstruction algorithms for nonstandard geometries. This work focuses on the application of Fourier analysis to the problem of resampling or rebinning. Conventional resampling methods utilizing some form of interpolation almost always result in a loss of resolution in the tomographic image. Fourier Transform Resampling (FTRS) offers potential improvement because the Modulation Transfer Function (MTF) of the process behaves like an ideal low pass filter. The MTF, however, is nonstationary if the coordinate transformation is nonlinear. FTRS may be viewed as a generalization of the linear coordinate transformations of standard Fourier analysis. Simulated MTF's were obtained by projecting point sources at different transverse positions in the flat fan beam detector geometry. These MTF's were compared to the closed form expression for FIRS. Excellent agreement was obtained for frequencies at or below the estimated cutoff frequency. The resulting FTRS algorithm is applied to simulations with symmetric fan beam geometry, an elliptical orbit and uniform attenuation, with a normalized root mean square error (NRME) of 0.036. Also, a Tc-99m point source study (1 cm dia., placed in air 10 cm from the COR) for a circular fan beam acquisition was reconstructed with a hybrid resampling method. The FWHM of the hybrid resampling method was 11.28 mm and compares favorably with a direct reconstruction (FWHM: 11.03 mm)

A novel algorithm for discrimination between inrush current and internal faults in power transformer differential protection based on discrete wavelet transform

Energy Technology Data Exchange (ETDEWEB)

Eldin, A.A. Hossam; Refaey, M.A. [Electrical Engineering Department, Alexandria University, Alexandria (Egypt)

2011-01-15

This paper proposes a novel methodology for transformer differential protection, based on wave shape recognition of the discriminating criterion extracted of the instantaneous differential currents. Discrete wavelet transform has been applied to the differential currents due to internal fault and inrush currents. The diagnosis criterion is based on median absolute deviation (MAD) of wavelet coefficients over a specified frequency band. The proposed algorithm is examined using various simulated inrush and internal fault current cases on a power transformer that has been modeled using electromagnetic transients program EMTDC software. Results of evaluation study show that, proposed wavelet based differential protection scheme can discriminate internal faults from inrush currents. (author)

The Fractional Fourier Transform and Its Application to Energy Localization Problems

Directory of Open Access Journals (Sweden)

ter Morsche Hennie G

2003-01-01

Full Text Available Applying the fractional Fourier transform (FRFT and the Wigner distribution on a signal in a cascade fashion is equivalent to a rotation of the time and frequency parameters of the Wigner distribution. We presented in ter Morsche and Oonincx, 2002, an integral representation formula that yields affine transformations on the spatial and frequency parameters of the -dimensional Wigner distribution if it is applied on a signal with the Wigner distribution as for the FRFT. In this paper, we show how this representation formula can be used to solve certain energy localization problems in phase space. Examples of such problems are given by means of some classical results. Although the results on localization problems are classical, the application of generalized Fourier transform enlarges the class of problems that can be solved with traditional techniques.

Multisensor signal denoising based on matching synchrosqueezing wavelet transform for mechanical fault condition assessment

Science.gov (United States)

Yi, Cancan; Lv, Yong; Xiao, Han; Huang, Tao; You, Guanghui

2018-04-01

Since it is difficult to obtain the accurate running status of mechanical equipment with only one sensor, multisensor measurement technology has attracted extensive attention. In the field of mechanical fault diagnosis and condition assessment based on vibration signal analysis, multisensor signal denoising has emerged as an important tool to improve the reliability of the measurement result. A reassignment technique termed the synchrosqueezing wavelet transform (SWT) has obvious superiority in slow time-varying signal representation and denoising for fault diagnosis applications. The SWT uses the time-frequency reassignment scheme, which can provide signal properties in 2D domains (time and frequency). However, when the measured signal contains strong noise components and fast varying instantaneous frequency, the performance of SWT-based analysis still depends on the accuracy of instantaneous frequency estimation. In this paper, a matching synchrosqueezing wavelet transform (MSWT) is investigated as a potential candidate to replace the conventional synchrosqueezing transform for the applications of denoising and fault feature extraction. The improved technology utilizes the comprehensive instantaneous frequency estimation by chirp rate estimation to achieve a highly concentrated time-frequency representation so that the signal resolution can be significantly improved. To exploit inter-channel dependencies, the multisensor denoising strategy is performed by using a modulated multivariate oscillation model to partition the time-frequency domain; then, the common characteristics of the multivariate data can be effectively identified. Furthermore, a modified universal threshold is utilized to remove noise components, while the signal components of interest can be retained. Thus, a novel MSWT-based multisensor signal denoising algorithm is proposed in this paper. The validity of this method is verified by numerical simulation, and experiments including a rolling

No effects of power line frequency extremely low frequency electromagnetic field exposure on selected neurobehavior tests of workers inspecting transformers and distribution line stations versus controls.

Science.gov (United States)

Li, Li; Xiong, De-fu; Liu, Jia-wen; Li, Zi-xin; Zeng, Guang-cheng; Li, Hua-liang

2014-03-01

We aimed to evaluate the interference of 50 Hz extremely low frequency electromagnetic field (ELF-EMF) occupational exposure on the neurobehavior tests of workers performing tour-inspection close to transformers and distribution power lines. Occupational short-term "spot" measurements were carried out. 310 inspection workers and 300 logistics staff were selected as exposure and control. The neurobehavior tests were performed through computer-based neurobehavior evaluation system, including mental arithmetic, curve coincide, simple visual reaction time, visual retention, auditory digit span and pursuit aiming. In 500 kV areas electric field intensity at 71.98% of total measured 590 spots were above 5 kV/m (national occupational standard), while in 220 kV areas electric field intensity at 15.69% of total 701 spots were above 5 kV/m. Magnetic field flux density at all the spots was below 1,000 μT (ICNIRP occupational standard). The neurobehavior score changes showed no statistical significance. Results of neurobehavior tests among different age, seniority groups showed no significant changes. Neurobehavior changes caused by daily repeated ELF-EMF exposure were not observed in the current study.

Frequency Domain Image Filtering Using CUDA

Directory of Open Access Journals (Sweden)

Muhammad Awais Rajput

2014-10-01

Full Text Available In this paper, we investigate the implementation of image filtering in frequency domain using NVIDIA?s CUDA (Compute Unified Device Architecture. In contrast to signal and image filtering in spatial domain which uses convolution operations and hence is more compute-intensive for filters having larger spatial extent, the frequency domain filtering uses FFT (Fast Fourier Transform which is much faster and significantly reduces the computational complexity of the filtering. We implement the frequency domain filtering on CPU and GPU respectively and analyze the speed-up obtained from the CUDA?s parallel processing paradigm. In order to demonstrate the efficiency of frequency domain filtering on CUDA, we implement three frequency domain filters, i.e., Butterworth, low-pass and Gaussian for processing different sizes of images on CPU and GPU respectively and perform the GPU vs. CPU benchmarks. The results presented in this paper show that the frequency domain filtering with CUDA achieves significant speed-up over the CPU processing in frequency domain with the same level of (output image quality on both the processing architectures

Frequency domain image filtering using cuda

International Nuclear Information System (INIS)

Rajput, M.A.; Khan, U.A.

2014-01-01

In this paper, we investigate the implementation of image filtering in frequency domain using NVIDIA's CUDA (Compute Unified Device Architecture). In contrast to signal and image filtering in spatial domain which uses convolution operations and hence is more compute-intensive for filters having larger spatial extent, the frequency domain filtering uses FFT (Fast Fourier Transform) which is much faster and significantly reduces the computational complexity of the filtering. We implement the frequency domain filtering on CPU and GPU respectively and analyze the speed-up obtained from the CUDA's parallel processing paradigm. In order to demonstrate the efficiency of frequency domain filtering on CUDA, we implement three frequency domain filters, i.e., Butter worth, low-pass and Gaussian for processing different sizes of images on CPU and GPU respectively and perform the GPU vs. CPU benchmarks. The results presented in this paper show that the frequency domain filtering with CUDA achieves significant speed-up over the CPU processing in frequency domain with the same level of (output) image quality on both the processing architectures. (author)

Biolistic transformation of Scoparia dulcis L.

Science.gov (United States)

Srinivas, Kota; Muralikrishna, Narra; Kumar, Kalva Bharath; Raghu, Ellendula; Mahender, Aileni; Kiranmayee, Kasula; Yashodahara, Velivela; Sadanandam, Abbagani

2016-01-01

Here, we report for the first time, the optimized conditions for microprojectile bombardment-mediated genetic transformation in Vassourinha (Scoparia dulcis L.), a Plantaginaceae medicinal plant species. Transformation was achieved by bombardment of axenic leaf segments with Binary vector pBI121 harbouring β-glucuronidase gene (GUS) as a reporter and neomycin phosphotransferase II gene (npt II) as a selectable marker. The influence of physical parameters viz., acceleration pressure, flight distance, gap width & macroprojectile travel distance of particle gun on frequency of transient GUS and stable (survival of putative transformants) expressions have been investigated. Biolistic delivery of the pBI121 yielded the best (80.0 %) transient expression of GUS gene bombarded at a flight distance of 6 cm and rupture disc pressure/acceleration pressure of 650 psi. Highest stable expression of 52.0 % was noticed in putative transformants on RMBI-K medium. Integration of GUS and npt II genes in the nuclear genome was confirmed through primer specific PCR. DNA blot analysis showed more than one transgene copy in the transformed plantlet genomes. The present study may be used for metabolic engineering and production of biopharmaceuticals by transplastomic technology in this valuable medicinal plant.

Transformation of the Turkish Vocational Training System: Capitalization, Modularization and Learning unto Death

Science.gov (United States)

Bulut, Ergin

2010-01-01

This article scrutinizes the transformation of vocational training in Turkey. Entertaining the question, "Why did the vocational high schools become an issue in the country all of a sudden?", it aims to cover the social and economic dynamics behind this transformation. Establishing the link between Turkey's integration with the global…

Dispersive-cavity actively mode-locked fiber laser for stable radio frequency delivery

International Nuclear Information System (INIS)

Dai, Yitang; Wang, Ruixin; Yin, Feifei; Xu, Kun; Li, Jianqiang; Lin, Jintong

2013-01-01

We report a novel technique for highly stable transfer of a radio frequency (RF) comb over long optical fiber link, which is highly dispersive and is a part of an actively mode-locked fiber laser. Phase fluctuation along the fiber link, which is mainly induced by physical vibration and temperature fluctuations, is automatically compensated by the self-adapted wavelength shifting. Without phase-locking loop or any tunable parts, stable radio frequency is transferred over a 2-km fiber link, with a time jitter suppression ratio larger than 110. (letter)

Metamaterial-enabled transformation optics

Science.gov (United States)

Landy, Nathan

Transformation Optics is a design methodology that uses the form invariance of Maxwell's equations to distort electromagnetic fields. This distortion is imposed on a region of space by mimicking a curvilinear coordinate system with prescribed magnetoelectric material parameters. By simply specifying the correct coordinate transformation, researchers have created such exotic devices as invisibility cloaks, ``perfect'' lenses, and illusion devices. Unfortunately, these devices typically require correspondingly exotic material parameters that do not occur in Nature. Researchers have therefore turned to complex artificial media known as metamaterials to approximate the desired responses. However, the metamaterial design process is complex, and there are limitations on the responses that they achieve. In this dissertation, we explore both the applicability and limitations of metamaterials in Transformation Optics design. We begin in Chapter 2 by investigating the freedoms available to use in the transformation optics design process itself. We show that quasi-conformal mappings may be used to alleviate some of the complexity of material design in both two- and three-dimensional design. We then go on in Chapter 3 to apply this method to the design of a transformation-optics modified optic. We show that even a highly-approximate implementation of such a lens would retain many of the key performance feautures that we would expect from a full material prescription. However, the approximations made in the design of our lens may not be valid in other areas of transformation optical design. For instance, the high-frequency approximations of our lens design ignore the effects of impedance mismatch, and the approximation is not valid when the material parameters vary on the order of a wavelength. Therefore, in Chapter 4 we use other freedoms available to us to design a full-parameter cloak of invisibility. By tailoring the electromagnetic environment of our cloak, we are able to

KSI's Cross Insulated Core Transformer Technology

International Nuclear Information System (INIS)

Uhmeyer, Uwe

2009-01-01

Cross Insulated Core Transformer (CCT) technology improves on Insulated Core Transformer (ICT) implementations. ICT systems are widely used in very high voltage, high power, power supply systems. In an ICT transformer ferrite core sections are insulated from their neighboring ferrite cores. Flux leakage is present at each of these insulated gaps. The flux loss is raised to the power of stages in the ICT design causing output voltage efficiency to taper off with increasing stages. KSI's CCT technology utilizes a patented technique to compensate the flux loss at each stage of an ICT system. Design equations to calculate the flux compensation capacitor value are presented. CCT provides corona free operation of the HV stack. KSI's CCT based High Voltage power supply systems offer high efficiency operation, high frequency switching, low stored energy and smaller size over comparable ICT systems.

Conditional flood frequency and catchment state: a simulation approach

Science.gov (United States)

Brettschneider, Marco; Bourgin, François; Merz, Bruno; Andreassian, Vazken; Blaquiere, Simon

2017-04-01

Catchments have memory and the conditional flood frequency distribution for a time period ahead can be seen as non-stationary: it varies with the catchment state and climatic factors. From a risk management perspective, understanding the link of conditional flood frequency to catchment state is a key to anticipate potential periods of higher flood risk. Here, we adopt a simulation approach to explore the link between flood frequency obtained by continuous rainfall-runoff simulation and the initial state of the catchment. The simulation chain is based on i) a three state rainfall generator applied at the catchment scale, whose parameters are estimated for each month, and ii) the GR4J lumped rainfall-runoff model, whose parameters are calibrated with all available data. For each month, a large number of stochastic realizations of the continuous rainfall generator for the next 12 months are used as inputs for the GR4J model in order to obtain a large number of stochastic realizations for the next 12 months. This process is then repeated for 50 different initial states of the soil moisture reservoir of the GR4J model and for all the catchments. Thus, 50 different conditional flood frequency curves are obtained for the 50 different initial catchment states. We will present an analysis of the link between the catchment states, the period of the year and the strength of the conditioning of the flood frequency compared to the unconditional flood frequency. A large sample of diverse catchments in France will be used.

Remote Sensing Image Enhancement Based on Non-subsampled Shearlet Transform and Parameterized Logarithmic Image Processing Model

Directory of Open Access Journals (Sweden)

TAO Feixiang

2015-08-01

Full Text Available Aiming at parts of remote sensing images with dark brightness and low contrast, a remote sensing image enhancement method based on non-subsampled Shearlet transform and parameterized logarithmic image processing model is proposed in this paper to improve the visual effects and interpretability of remote sensing images. Firstly, a remote sensing image is decomposed into a low-frequency component and high frequency components by non-subsampled Shearlet transform.Then the low frequency component is enhanced according to PLIP (parameterized logarithmic image processing model, which can improve the contrast of image, while the improved fuzzy enhancement method is used to enhance the high frequency components in order to highlight the information of edges and details. A large number of experimental results show that, compared with five kinds of image enhancement methods such as bidirectional histogram equalization method, the method based on stationary wavelet transform and the method based on non-subsampled contourlet transform, the proposed method has advantages in both subjective visual effects and objective quantitative evaluation indexes such as contrast and definition, which can more effectively improve the contrast of remote sensing image and enhance edges and texture details with better visual effects.

Use of muscle synergies and wavelet transforms to identify fatigue during squatting.

Science.gov (United States)

Smale, Kenneth B; Shourijeh, Mohammad S; Benoit, Daniel L

2016-06-01

The objective of this study was to supplement continuous wavelet transforms with muscle synergies in a fatigue analysis to better describe the combination of decreased firing frequency and altered activation profiles during dynamic muscle contractions. Nine healthy young individuals completed the dynamic tasks before and after they squatted with a standard Olympic bar until complete exhaustion. Electromyography (EMG) profiles were analyzed with a novel concatenated non-negative matrix factorization method that decomposed EMG signals into muscle synergies. Muscle synergy analysis provides the activation pattern of the muscles while continuous wavelet transforms output the temporal frequency content of the EMG signals. Synergy analysis revealed subtle changes in two-legged squatting after fatigue while differences in one-legged squatting were more pronounced and included the shift from a general co-activation of muscles in the pre-fatigue state to a knee extensor dominant weighting post-fatigue. Continuous wavelet transforms showed major frequency content decreases in two-legged squatting after fatigue while very few frequency changes occurred in one-legged squatting. It was observed that the combination of methods is an effective way of describing muscle fatigue and that muscle activation patterns play a very important role in maintaining the overall joint kinetics after fatigue. Copyright © 2016 Elsevier Ltd. All rights reserved.

Remembering Apple CEO Steve Jobs as a "Transformational Leader": Implications for Pedagogy

Science.gov (United States)

Steinwart, Marlane C.; Ziegler, Jennifer A.

2014-01-01

This paper explores the implications of using Apple co-founder and former CEO Steve Jobs as a "paradigm case" of transformational leadership by comparing the practical metadiscourse of remembrances published at the time of his passing to the theoretical metadiscourse of transformational leadership. The authors report the frequency of…

The Linear Time Frequency Analysis Toolbox

DEFF Research Database (Denmark)

Søndergaard, Peter Lempel; Torrésani, Bruno; Balazs, Peter

2011-01-01

The Linear Time Frequency Analysis Toolbox is a Matlab/Octave toolbox for computational time-frequency analysis. It is intended both as an educational and computational tool. The toolbox provides the basic Gabor, Wilson and MDCT transform along with routines for constructing windows (lter...... prototypes) and routines for manipulating coe cients. It also provides a bunch of demo scripts devoted either to demonstrating the main functions of the toolbox, or to exemplify their use in specic signal processing applications. In this paper we describe the used algorithms, their mathematical background...

On chip frequency discriminator for microwave photonics signal processing

NARCIS (Netherlands)

Marpaung, D.A.I.; Roeloffzen, C.G.H.

2012-01-01

Microwave photonics (MWP) techniques for the generation, distribution and pro- cessing of radio frequency (RF) signals have enjoyed a surge of interest in the last few years. The workhorse behind these MWP functionalities is a high performance MWP link. Such a link needs to fulfill several criteria

An efficient protocol for the Agrobacterium-mediated genetic transformation of microalga Chlamydomonas reinhardtii.

Science.gov (United States)

Pratheesh, P T; Vineetha, M; Kurup, G Muraleedhara

2014-06-01

Algal-based recombinant protein production has gained immense interest in recent years. The development of algal expression system was earlier hindered due to the lack of efficient and cost-effective transformation techniques capable of heterologous gene integration and expression. The recent development of Agrobacterium-mediated genetic transformation method is expected to be the ideal solution for these problems. We have developed an efficient protocol for the Agrobacterium-mediated genetic transformation of microalga Chlamydomonas reinhardtii. Pre-treatment of Agrobacterium in TAP induction medium (pH 5.2) containing 100 μM acetosyringone and 1 mM glycine betaine and infection of Chlamydomonas with the induced Agrobacterium greatly improved transformation frequency. This protocol was found to double the number of transgenic events on selection media compared to that of previous reports. PCR was used successfully to amplify fragments of the hpt and GUS genes from transformed cells, while Southern blot confirmed the integration of GUS gene into the genome of C. reinhardtii. RT-PCR, Northern blot and GUS histochemical analyses confirm GUS gene expression in the transgenic cell lines of Chlamydomonas. This protocol provides a quick, efficient, economical and high-frequency transformation method for microalgae.

Improvements in the transformation of Arabidopsis thaliana C24 leaf-discs by Agrobacterium tumefaciens

DEFF Research Database (Denmark)

van der Graaff, Eric; Hooykaas, P J

1996-01-01

We report here an efficient Arabidopsis leafdisc transformation protocol yielding an average transformation frequency of 1.6 transgenic shoots per leaf explant 4 weeks after the bacterial infection period. Subsequent cultivation in vitro is such that a high percentage (85-90%) of the primary...... transformants produces seeds with an average seed yield of 100-300 seeds per plant. This improved transformation protocol yields mainly (70%) transformants segregating for a single T-DNA locus of which 68% actually contain one T-DNA insert. The objective is to generate a pool of independent transformants...

Time-domain modeling of electromagnetic diffusion with a frequency-domain code

NARCIS (Netherlands)

Mulder, W.A.; Wirianto, M.; Slob, E.C.

2007-01-01

We modeled time-domain EM measurements of induction currents for marine and land applications with a frequency-domain code. An analysis of the computational complexity of a number of numerical methods shows that frequency-domain modeling followed by a Fourier transform is an attractive choice if a

Dissemination of optical-comb-based ultra-broadband frequency reference through a fiber network.

Science.gov (United States)

Nagano, Shigeo; Kumagai, Motohiro; Li, Ying; Ido, Tetsuya; Ishii, Shoken; Mizutani, Kohei; Aoki, Makoto; Otsuka, Ryohei; Hanado, Yuko

2016-08-22

We disseminated an ultra-broadband optical frequency reference based on a femtosecond (fs)-laser optical comb through a kilometer-scale fiber link. Its spectrum ranged from 1160 nm to 2180 nm without additional fs-laser combs at the end of the link. By employing a fiber-induced phase noise cancellation technique, the linewidth and fractional frequency instability attained for all disseminated comb modes were of order 1 Hz and 10-18 in a 5000 s averaging time. The ultra-broad optical frequency reference, for which absolute frequency is traceable to Japan Standard Time, was applied in the frequency stabilization of an injection-seeded Q-switched 2051 nm pulse laser for a coherent light detection and ranging LIDAR system.

E- and W-band high-capacity hybrid fiber-wireless link

DEFF Research Database (Denmark)

Vegas Olmos, Juan José; Pang, Xiaodan; Tafur Monroy, Idelfonso

2014-01-01

In this paper we summarize the work conducted in our group in the area of E- and W-band optical high-capacity fiber-wireless links. We present performance evaluations of E- and W-band mm-wave signal generation using photonic frequency upconversion employing both VCSELs and ECLs, along with transm...... in mobile backhaul/fronthaul applications, dense distributed antenna systems and fiber-over-radio scenarios.......In this paper we summarize the work conducted in our group in the area of E- and W-band optical high-capacity fiber-wireless links. We present performance evaluations of E- and W-band mm-wave signal generation using photonic frequency upconversion employing both VCSELs and ECLs, along...... with transmission over different type of optical fibers and for a number of values for the wireless link distance. Hybrid wireless-optical links can be composed of mature and resilient technology available off-the-shelf, and provide functionalities that can add value to optical access networks, specifically...

Design of fixed frequency controlled radial-mode stacked disk-type piezoelectric transformers for DC/DC converter applications

International Nuclear Information System (INIS)

Liu, Yuan-Ping; Vasic, Dejan; Costa, François; Wu, Wen-Jong; Lee, Chih-Kung

2009-01-01

In this paper, we propose a new design procedure to determine the optimal size of a piezoelectric transformer (PT) for DC/DC converter applications. We examined several parameters, which allows us to produce a piezoelectric transformer with optimal efficiency and which has an optimal range for regulating voltage. The characteristics of a piezoelectric transformer (PT) are well known when the load impedance is a pure resistor. However, when piezoelectric transformers are used in AC/DC or DC/DC converter applications, it requires the presence of a rectifier circuit block. A rectifier is usually a nonlinear device which does not act like a pure resistor. We began by modeling a full-wave rectifier directly in order to understand the design constraint variables such as the maximum mechanical current, the piezoelectric transformer configuration, and the energy balance of the PT configuration. In our final design, a stacked disk-type piezoelectric transformer with radial-mode vibration was chosen due to the large number of design parameters required. In our new design procedure, instead of just looking at the typical optimal loading condition of the PT, we used the concept of a maximum mechanical current to determine the new optimal efficiency which is suitable for voltage regulation. From our results we found that the size of the piezoelectric transformer and efficiency are trade-offs which means that they have an inverse relationship. In summary, we developed a new design procedure to determine the optimal size of a piezoelectric transformer, which we found to be small but with high efficiency so as to provide an optimal range for regulating voltage

Chromosome alterations in the X-ray-induced transformants of cultured mouse cell line

International Nuclear Information System (INIS)

Kodama, Seiji; Komatsu, Kenshi; Okumura, Yutaka; Sasaki, M.S.

1989-01-01

Mouse m5S cells were subjected to soft X-ray irradiation. Twenty-four transformants were separated as indicators of focus formation. Two clones, cl.4103 and cl.6310, were chosen for the analysis of chromosome alterations in transformants. A parent strain, m5S/1M, served as the control. Anchorage independence (AG) was not detected in the control strain, irrespective of culture conditions and population doubling number (PDN). In the case of transformants, the frequency of AG was increased with increasing PDN for cl.4103, and was constant for cl.6310, irrespective of PDN. Karyotype of m5S/1M was 42, X, -Y, +der (6) t(6;13), t(8;8), +8, +15. In addition, -13, der(10) and -der(6)t(6;13), der(5), +mar occurred as karyotype alterations for cl.4103 and cl. 6310, respectively. The present experiment indicated that chromosome alterations secondary to primary alterations occur in a high frequency in the transforming process of X-ray irradiated cells, and that the secondary chromosome alterations result in selective proliferation of transformed clones. (Namekawa, K)

The efficiency of Arabidopsis thaliana floral dip transformation is determined not only by the Agrobacterium strain used but also by the physiology and the ecotype of the dipped plant.

Science.gov (United States)

Ghedira, Rim; De Buck, Sylvie; Nolf, Jonah; Depicker, Ann

2013-07-01

To evaluate the chromosomal background of different Agrobacterium strains on floral dip transformation frequency, eight wild-type Agrobacterium strains, provided by Laboratorium voor Microbiologie Gent (LMG) and classified in different genomic groups, were compared with the commonly used Agrobacterium strains C58C1 Rif(r) (pMP90) and LBA4404 in Arabidopsis thaliana Columbia (Col-0) and C24 ecotypes. The C58C1 Rif(r) chromosomal background in combination with the pMP90 virulence plasmid showed high Col-0 floral dip transformation frequencies (0.76 to 1.57%). LMG201, which is genetically close to the Agrobacterium C58 strain, with the same virulence plasmid showed comparable or even higher transformation frequencies (1.22 to 2.28%), whereas the LBA4404 strain displayed reproducibly lower transformation frequencies (Agrobacterium chromosomal backgrounds had transformation frequencies between those of the C58C1 Rif(r) (pMP90) and LBA4404 reference strains. None of the strains could transform the C24 ecotype with a frequency higher than 0.1%. Strikingly, all Arabidopsis Col-0 floral dip transformation experiments showed a high transformation variability from plant to plant (even more than 50-fold) within and across the performed biological repeats for all analyzed Agrobacterium strains. Therefore, the physiology of the plant and, probably, the availability of competent flowers to be transformed determine, to a large extent, floral dip transformation frequencies.

In situ measurement of solvent-mediated phase transformations during dissolution testing

DEFF Research Database (Denmark)

Aaltonen, Jaakko; Heinänen, Paula; Peltonen, Leena

2006-01-01

In this study, solvent-mediated phase transformations of theophylline (TP) and nitrofurantoin (NF) were measured in a channel flow intrinsic dissolution test system. The test set-up comprised simultaneous measurement of drug concentration in the dissolution medium (with UV-Vis spectrophotometry......) and measurement of the solid-state form of the dissolving solid (in situ with Raman spectroscopy). The solid phase transformations were also investigated off-line with scanning electron microscopy. TP anhydrate underwent a transformation to TP monohydrate, and NF anhydrate (form beta) to NF monohydrate (form II......). Transformation of TP anhydrate to TP monohydrate resulted in a clear decrease in the dissolution rate, while the transformation of NF anhydrate (form beta) to NF monohydrate (form II) could not be linked as clearly to changes in the dissolution rate. The transformation of TP was an order of magnitude faster than...

Comparison of different spatial transformations applied to EEG data: A case study of error processing

NARCIS (Netherlands)

Cohen, M.X.

2015-01-01

The purpose of this paper is to compare the effects of different spatial transformations applied to the same scalp-recorded EEG data. The spatial transformations applied are two referencing schemes (average and linked earlobes), the surface Laplacian, and beamforming (a distributed source

In vitro transformation: interactions of chemical carcinogens and radiation

International Nuclear Information System (INIS)

DiPaolo, J.A.

1976-01-01

The development of reproducible quantitative in vitro procedures resulting in neoplastic transformation of mammalian cells has made possible the separation of events related to the process leading to transformation from secondary events that interfere with the early recognition of transformation. The use of chemical carcinogens on Syrian hamster cell strains results in a dose-response relation consistent with a Poisson distribution, indicating that the transformation phenomenon is inductive. In some circumstances, the joint action or interaction of chemical carcinogens with other agents results in an increased incidence of transformation. The pretreatment of Syrian hamster cells with ionizing radiation (250 R) or alkylating chemicals enhances the frequency of transformation on a cell or colony basis ordinarily obtained with known chemical carcinogens. Pretreatment with non-ionizing irradiation (uv, 254 nm) did not have a similar effect. The two types of irradiation and the alkylating agents reduced the cloning efficiency of the cells. X ray alone produced no transformation; the alkylating chemicals produced transformations infrequently, whereas uv produced a significant number of transformations. The number of transformations associated with uv is increased by pretreatment of the cells by x-irradiation. The enhancement of transformation by x-ray or x-ray-type agents appears to be independent of the type of second carcinogen used

Characteristics of radiation-induced neoplastic transformation in vitro

Energy Technology Data Exchange (ETDEWEB)

Little, J.B.

1986-01-01

Data are presented to support the hypothesis that the initial step in the morphologic transformation of irradiated rodent (BALB/3T3) cells is a frequent cellular event involving a large fraction of the irradiated population. This process appears to involve DNA damage, but not to represent a targeted mutation in specific structural gene(s). Morphologic transformation and immortalization appear to be distinct steps in the overall process of transformation. In contradistinction to rodent cells, immortalization is a very rare event in human diploid cells which is induced at extremely low frequencies. The hypothesis is presented that immortality develops among clones of cells bearing stable chromosomal rearrangements which emerge during the proliferation of a population of radiation damaged cells.

Dynamic temperature field in the ferromagnetic plate induced by moving high frequency inductor

Directory of Open Access Journals (Sweden)

Milošević-Mitić Vesna

2014-01-01

Full Text Available The subject of the paper is the temperature distribution in the thin metallic ferromagnetic plate influenced by moving linear high frequency induction heater. As a result of high frequency electromagnetic field, conducting currents appear in the part of the plate. Distribution of the eddy-current power across the plate thickness is obtained by use of complex analysis. The influences of the heater frequency, magnetic field intensity and plate thickness on the heat power density were discussed. By treating this power as a moving heat source, differential equations governing distribution of the temperature field are formulated. Temperature across the plate thickness is assumed to be in linear form. Differential equations are analytically solved by using integral-transform technique, Fourier finite-sine and finite-cosine transform and Laplace transform. The influence of the heater velocity to the plate temperature is presented on numerical examples based on theoretically obtained results. [Projekat Ministarstva nauke Republike Srbije, br. TR 35040 i br. TR 35011

[Chromosome abnormalities associated with Phl and acturial survivorship curve in chronic myeloid leukemia. Probabilistic interpretation of blastic transformation of CML].

Science.gov (United States)

Coutris, G

1981-12-01

Sixty-six patients with chronic myelogenous leukemia, all with Philadelphia chromosome, have been studied for chromosomic abnormalities associated (CAA) to Ph', as well as for actuarial curve of survivorship. Patients dying from another disease were excluded from this study. Frequency of cells with CAA was measured and appeared strongly higher after blastic transformation than during myelocytic state; probability to be a blastic transformation is closely correlated with this frequency. On the other hand, actuarial curve of survivorship is very well represented by an exponential curve. This suggests a constant rate of death during disease evolution, for these patients without intercurrent disease. As a mean survivance after blastic transformation is very shorter than myelocytic duration, a constant rate of blastic transformation could be advanced: it explains possible occurrence of transformation as soon as preclinic state of a chronic myelogenous leukemia. Even if CAA frequency increases after blastic transformation, CAA can occur a long time before it and do not explain it: submicroscopic origin should be searched for the constant rate of blastic transformation would express the risk of a genic transformation at a constant rate during myelocytic state.

A reversible transform for seismic data processing

International Nuclear Information System (INIS)

Burnett, William A; Ferguson, Robert J

2011-01-01

We use the nonstationary equivalent of the Fourier shift theorem to derive a general one-dimensional integral transform for the application and removal of certain seismic data processing steps. This transform comes from the observation that many seismic data processing steps can be viewed as nonstationary shifts. The continuous form of the transform is exactly reversible, and the discrete form provides a general framework for unitary and pseudounitary imaging operators. Any processing step which can be viewed as a nonstationary shift in any domain is a special case of this transform. Nonstationary shifts generally produce coordinate distortions between input and output domains, and those that preserve amplitudes do not conserve the energy of the input signal. The nonstationary frequency distortions, time distortions and nonphysical energy changes inherent to such operations are predicted and quantified by this transform. Processing steps of this type are conventionally implemented using interpolation operators to map discrete data values between input and output coordinate frames. Although not explicitly derived to perform interpolation, the transform here assumes the Fourier basis to predict values of the input signal between sampling locations. We demonstrate how interpolants commonly used in seismic data processing and imaging approximate the proposed method. We find that our transform is equivalent to the conventional sinc interpolant with no truncation. Once the transform is developed, we demonstrate its numerical implementation by matrix–vector multiplication. As an example, we use our transform to apply and remove normal moveout