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Sample records for intermodulation distortion microwave

  1. A general approach for the calculation of intermodulation distortion in cavities with superconducting endplates

    Science.gov (United States)

    Mateu, J.; Collado, C.; Menéndez, O.; O'Callaghan, J. M.

    2003-01-01

    We report on a general procedure to calculate intermodulation distortion in cavities with superconducting endplates that is applicable to the dielectric-loaded cavities currently used for measurement of surface resistance in high-temperature superconductors. The procedure would enable the use such cavities for intermodulation characterization of unpatterned superconducting films, and would remove the uncertainty of measuring intermodulation on patterned devices, in which the effect of patterning damage might influence the outcome of the measurements. We have verified the calculation method by combining superconducting and copper endplates in a rutile-loaded cavity.

  2. EVALUATION OF POWER SPECTRAL DENSITY OF PASSIVE INTERMODULATION DISTORTION IN HIGH-POWER COMMUNICATION SATELLITE SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    Zhang Shiquan; Ge Debiao

    2005-01-01

    In order to analyze the deleterious effects of Passive InterModulation (PIM) on high power communication satellite systems, the basic concept of PIM is introduced, and an equation for the power spectral density of the n-th order PIM distortion insuch systems is derived by applying flat signal-power spectrum assumption and Fourier transform method. It is indicated that PIM level generally decreases with order and the lowest frequency receive channel in the receive band is the channel of most affected by PIM interference.

  3. Direct Determination of Harmonic and Inter-modulation distortions with an application to Single Mode Laser Diodes

    CERN Document Server

    Tannous, C

    2001-01-01

    Harmonic and Intermodulation distortions occur when a physical system is excited with a single or several frequencies and when the relationship between the input and output is non-linear. Working with non-linearities in the Frequency domain is not straightforward specially when the relationship between the input and output is not trivial. We outline the complete derivation of the Harmonic and Intermodulation distortions from basic principles to a general physical system. For illustration, the procedure is applied to the Single Mode laser diode where the relationship of input to output is non-trivial. The distortions terms are extracted directly from the Laser Diode rate equations and the method is tested by comparison to many results cited in the literature. This methodology is general enough to be applied to the extraction of distortion terms to any desired order in many physical systems in a general and systematic way.

  4. Analysis of Intermodulation Distortion in OFDM Based Transmitter Using EER Technique

    Directory of Open Access Journals (Sweden)

    S. Matejka

    2016-06-01

    Full Text Available During the last two decades, new digital modulation systems have appeared in the audio broadcasting. Such broadcasting systems require new transmitters’ concepts to enable the transmission of digitally modulated signals. Moreover, the selected modulation schemes (e.g. orthogonal frequency division multiplexing require a high linearity power stage, which typically exhibits low efficiency due to high peak-toaverage power ratio of the modulated signal. One of the promising transmitter concepts is the Kahn envelope elimination and restoration technique, where the original Cartesian in-phase and quadrature baseband signals are transformed to the envelope and phase signals. The main advantage of this technique is an ability to employ suitable types of highly efficient amplitude modulation transmitters for envelope amplification, while the phase modulated carrier is produced by an additional phase modulator. The substantial drawback of envelope elimination and restoration is nonideal recombination of linearly distorted amplitude signal and phase modulated carrier at the output power stage. The aim of this paper is twofold. Firstly, to analyze the effect of the envelope and phase signals bandwidth limitation on the modulated signal in-channel distortion and out-ofchannel emission. Secondly, to present the performance results as a reference for transmitter designers to properly set the envelope and phase paths to reach required in-channel signal quality and suppress out-of-channel products.

  5. Harmonic distortion in microwave photonic filters.

    Science.gov (United States)

    Rius, Manuel; Mora, José; Bolea, Mario; Capmany, José

    2012-04-09

    We present a theoretical and experimental analysis of nonlinear microwave photonic filters. Far from the conventional condition of low modulation index commonly used to neglect high-order terms, we have analyzed the harmonic distortion involved in microwave photonic structures with periodic and non-periodic frequency responses. We show that it is possible to design microwave photonic filters with reduced harmonic distortion and high linearity even under large signal operation.

  6. Analysis and Improvement of CDMA Optical Module Intermodulation Distortion Characteristics%CDMA光模块交调失真特性分析及其改善

    Institute of Scientific and Technical Information of China (English)

    胡新艳; 刘金梅; 李爱涛; 霍文晓

    2013-01-01

      针对通信系统中CDMA光模块的非线性失真对整个系统性能的影响问题,本文从激光器和放大器两方面出发,通过采用三阶交调截点(IP3)和三阶交调产物(IM3)参数作为衡量CDMA光模块非线性失真的指标,详细地分析了光模块的失真特性,并在此基础上初步探讨了改善CDMA模块失真的基本方法,包括改变模块内部激光器的偏置电流,放大器的偏流及外围匹配电路在内的一系列方法。实验通过观察条件的改变对IP3和IM3的影响从而证实文中提出的方法行之有效,均能从一定程度上改善系统的失真指标。目前国内外对此类失真特性的研究一般集中在电性能上,对光器件与电器件相结合的研究涉及较少,本文提出的方法对实际商用化光模块产品有一定的借鉴意义,具有一定的使用价值。%Nonlinear distortion of CDMA optical module has severely affected the whole system performance in a communication system, for the problem, by the use of IP3(the third-order Intercept point) and IM3(third-order intermodulation signal) parameters as an index of measuring CDMA optical module nonlinear distortion, and distortion properties of optical modules is analyzed in detail from two aspects including lasers and amplifiers. On this basis, basic methods to improve the CDMA module distortion are discussed preliminarily, such a series of methods as changes to module internal laser bias currents, amplifier bias currents and peripheral matching circuits, and etc. The experimental results demonstrate that the proposed method is effective, which can improve the system distortion index in a certain degree, by watching influence on IP3 and IM3 parameters when condition changes. At present, the research for such distortion characteristics generally concentrated on the electrics, less on the optical devices combined with electrical devices at home and abroad. The method has certain

  7. Imaging calibration of thermoacoustic tomography distortion caused by microwave diffraction

    Science.gov (United States)

    Nie, Liming; Xing, Da

    2009-08-01

    A uniform energy field of microwave illumination on sample is assumed for microwave-induced thermoacoustic tomography. However, microwave transmitting out of the waveguide surface is nonuniform due to microwave diffraction, which would lead to uneven excitation of thermoacoustic pressure. Hence, the thermoacoustic images may be distorted especially at the edge of microwave radiation. A fast thermoacoustic tomography system at 6 GHz was developed for phantom study and in vivo animals imaging. The effects of microwave distribution inhomogeneity on nonuniform excitation of acoustic pressure were theoretically studied and a corresponding calibration algorithm for image distortion was also provided and experimentally verified. The distribution formulas of microwave field were derived using a Huygens diffraction principle model. Then a point microwave absorber moved under the microwave waveguide to measure the microwave field distribution. The measure data is in good agreement with the deduced result. Once the calibration map was obtained via the theoretical calculation, the TAT (thermoacoustic tomography) images could be calibrated by dividing the reconstructed image by the calibration map. Thermoacoustic images without and with calibration were reconstructed for comparison. According to the statistical results, after calibration the thermoacoustic contrast can be enhanced 2 times or more. Also it can be supposed that the farther the distance away from the illumination centre, the greater signal-noise-ratio (SNR) could be enhanced by the calibration. The results of experiment showed that this method could achieve even distribution of SNR and improve the reconstructed image quality. Therefore, this calibration method has potential application in solving the problem of imaging distortion especially at the edge of microwave illumination.

  8. The Intermodulation Lockin Analyzer

    CERN Document Server

    Tholen, Erik A; Forchheimer, Daniel; Schuler, Vivien; Tholen, Mats O; Hutter, Carsten; Haviland, David B

    2011-01-01

    Nonlinear systems can be probed by driving them with two or more pure tones while measuring the intermodulation products of the drive tones in the response. We describe a digital lock-in analyzer which is designed explicitly for this purpose. The analyzer is implemented on a field-programmable gate array, providing speed in analysis, real-time feedback and stability in operation. The use of the analyzer is demonstrated for Intermodulation Atomic Force Microscopy. A generalization of the intermodulation spectral technique to arbitrary drive waveforms is discussed.

  9. On Distortion in Digital Microwave Power Amplifiers

    Science.gov (United States)

    Al-Mozani, Dhamia; Wentzel, Andreas; Heinrich, Wolfgang

    2017-01-01

    In this paper, a first study of distortion in digital power amplifiers (PA) is presented. The work is based on a voltage mode class-S PA with a GaN MMIC for the 900 MHz frequency band. The investigation focuses on the quasi-static amplitude-to-amplitude (AM-AM) and amplitude-to-phase (AM-PM) distortions. Different digital modulation schemes are applied and studied versus output power back-off. This includes two pulse-width modulation (PWM) versions as well as band-pass delta-sigma (BPDS) modulation. The results are verified by measurement data.

  10. Systematic distortion in cosmic microwave background maps

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    To minimize instrumentally the induced systematic errors,cosmic microwave background(CMB)anisotropy experiments measure temperature differences across the sky using pairs of horn antennas, temperature map is recovered from temperature difference obtained in sky survey through a map-making procedure.To inspect and calibrate residual systematic errors in the recovered temperature maps is important as most previous studies of cosmology are based on these maps.By analyzing pixel-ring coupling and latitude dependence of CMB temperatures,we find notable systematic devia- tion from CMB Gaussianity in released Wilkinson Microwave Anisotropy Probe(WMAP)maps.The detected deviation cannot be explained by the best-fit LCDM cosmological model at a confidence level above 99%and cannot be ignored for a precision cosmology study.

  11. Another look at distortions of the Cosmic Microwave Background spectrum

    Science.gov (United States)

    De Zotti, G.; Negrello, M.; Castex, G.; Lapi, A.; Bonato, M.

    2016-03-01

    We review aspects of Cosmic Microwave Background (CMB) spectral distortions which do not appear to have been fully explored in the literature. In particular, implications of recent evidences of heating of the intergalactic medium (IGM) by feedback from active galactic nuclei are investigated. Taking also into account the IGM heating associated to structure formation, we argue that values of the y parameter of several × 10-6, i.e. a factor of a few below the COBE/FIRAS upper limit, are to be expected. The Compton scattering by the re-ionized plasma also re-processes primordial distortions, adding a y-type contribution. Hence no pure Bose-Einstein-like distortions are to be expected. An assessment of Galactic and extragalactic foregrounds, taking into account the latest results from the Planck satellite as well as the contributions from the strong CII and CO lines from star-forming galaxies, demonstrates that a foreground subtraction accurate enough to fully exploit the PIXIE sensitivity will be extremely challenging. Motivated by this fact we also discuss methods to detect spectral distortions not requiring absolute measurements and show that accurate determinations of the frequency spectrum of the CMB dipole amplitude may substantially improve over COBE/FIRAS limits on distortion parameters. Such improvements may be at reach of next generation CMB anisotropy experiments. The estimated amplitude of the Cosmic Infrared Background (CIB) dipole might be detectable by careful analyses of Planck maps at the highest frequencies. Thus Planck might provide interesting constraints on the CIB intensity, currently known with a simeq 30% uncertainty.

  12. Simultaneous even- and third-order distortion suppression in a microwave photonic link based on orthogonal polarization modulation, balanced detection, and optical sideband filtering.

    Science.gov (United States)

    Han, Xiuyou; Chen, Xiang; Yao, Jianping

    2016-06-27

    A microwave photonic link (MPL) with simultaneous suppression of the even-order and third-order distortions using a polarization modulator (PolM), an optical bandpass filter (OBPF), and a balanced photodetector (BPD) is proposed and experimentally demonstrated. The even-order distortions are suppressed by utilizing orthogonal polarization modulation based on the PolM and balanced differential detection based on the BPD. The third-order distortions (IMD3) are suppressed by optimizing the spectral response of the OBPF with an optimal power ratio between the optical carrier and the sidebands of the phase-modulated signals from the PolM. Since the suppression of the IMD3 is achieved when the MPL is optimized for even-order distortion suppression, the proposed MPL can operate with simultaneous suppression of the even-order and third-order distortions. The proposed MPL is analyzed theoretically and is verified by an experiment. For a two-tone RF signal of f1 = 10 GHz and f2 = 19.95 GHz, the spurious-free dynamic range (SFDR2) is enhanced by 23.4 dB for the second harmonic (2f1), and 29.1 and 27.6 dB for the second intermodulation (f2-f1 and f1 + f2), as compared with a conventional MPL. For a two-tone RF signal of f1 = 9.95 GHz and f2 = 10 GHz, the SFDR3 is increased by 13.1 dB as compared with a conventional MPL.

  13. ANALYSIS AND MEASUREMENT OF LARGE DYNAMIC RANGE RF SWITCH INTER-MODULATION

    Institute of Scientific and Technical Information of China (English)

    Han Zhouan

    2008-01-01

    Radio Frequency (RF) switch circuit is the basic part of microwave devices and systems. The non-linearity distortion figure is necessary in the field of large dynamic range of signal. This letter analyzes the basic switch circuit and its inter-modulation, and studies in detail the measurement methods and systems of RF switch intercept point. It has provided cascaded simulation testing methods,which can accurately measure the PF switch, of which the second or third order intercept point value is above 75dB and 60dB, respectively. As the testing results are consistent with the theoretical analyses,it proves that the validity of the method satisfies the requirements of large scaled linearity measurement in engineering.

  14. 微波铁氧体器件三阶交调效应机理分析及设计验证%Mechanism analysis and design verification on 3rd order intermodulation in microwave ferrite device

    Institute of Scientific and Technical Information of China (English)

    闫欢; 蒋运石; 王亚东; 燕宣余; 袁兴武

    2016-01-01

    The magnetization precession equations’ expansion was derived under large signal microwave power load conditions. Combined with microwave transmission mode characteristics and boundary conditions of the high field disc junction circulator, the expressions of the third-order intercept point in the electric field were obtained. By the programming calculation, the dependence of the third-order intercept point was acquired on the amplitude of the input signal and the strength of the applied magnetic field. According to the calculation results, a high field junction circulator was designed and fabricated based on HFSS simulation, and the third-order intercept was tested,which was in good agreement with theoretical analysis, offering guidence for designing circulators and isdators with low intermodulation.%推导了在有大信号微波功率加载条件下铁氧体进动方程的展开式,结合高场圆盘结环行器中微波传播的模式特点及边界条件,得出了三阶交调电场的表达式。通过编程计算,得到了结式环行器三阶无源交调与输入信号幅度、外加磁场强度间的关系。根据计算结果,用 HFSS 仿真并制作了一款高场结式环行器,并对该环行器三阶交调性能进行了测试,测试结果与理论分析较为吻合,为通信用低交调指标环行器/隔离器提供设计指导。

  15. Performance optimization of RoF systems using 120° hybrid coupler for OSSB signal against third order intermodulation

    Science.gov (United States)

    Kumar, Parvin; Sharma, Sanjay Kumar; Singla, Shelly

    2016-10-01

    The performance of radio over fiber (RoF) system with dual drive Mach Zehender modulator has been optimized against third order intermodulation distortion by using 120° hybrid coupler in transmission system. Signal to Noise Distortion ratio (SNDR) has been evaluated and a performance comparison is also drawn for the systems based on 90° and 120° hybrid coupler in both noise and intermodulation distortion dominant environment. The SNDR is efficiently improved by employing 120° hybrid coupler in noise dominant and intermodulation distortion dominant environment. An improvement of 4.86 dB is obtained in the maximum SNDR with 120° hybrid coupler is obtained over at 20 km optical fiber length compared with a 90° hybrid coupler based system. A significant reduction of third order intermodulation power at receiver has also been observed with 120° hybrid coupler.

  16. Improving Quantum Gate Fidelities by Using a Qubit to Measure Microwave Pulse Distortions

    NARCIS (Netherlands)

    Gustavsson, Simon; Zwier, Olger; Bylander, Jonas; Yan, Fei; Yoshihara, Fumiki; Nakamura, Yasunobu; Orlando, Terry P.; Oliver, William D.

    2013-01-01

    We present a new method for determining pulse imperfections and improving the single-gate fidelity in a superconducting qubit. By applying consecutive positive and negative pi pulses, we amplify the qubit evolution due to microwave pulse distortions, which causes the qubit state to rotate around an

  17. Taking the Universe's Temperature with Spectral Distortions of the Cosmic Microwave Background.

    Science.gov (United States)

    Hill, J Colin; Battaglia, Nick; Chluba, Jens; Ferraro, Simone; Schaan, Emmanuel; Spergel, David N

    2015-12-31

    The cosmic microwave background (CMB) energy spectrum is a near-perfect blackbody. The standard model of cosmology predicts small spectral distortions to this form, but no such distortion of the sky-averaged CMB spectrum has yet been measured. We calculate the largest expected distortion, which arises from the inverse Compton scattering of CMB photons off hot, free electrons, known as the thermal Sunyaev-Zel'dovich (TSZ) effect. We show that the predicted signal is roughly one order of magnitude below the current bound from the COBE-FIRAS experiment, but it can be detected at enormous significance (≳1000σ) by the proposed Primordial Inflation Explorer (PIXIE). Although cosmic variance reduces the effective signal-to-noise ratio to 230σ, this measurement will still yield a subpercent constraint on the total thermal energy of electrons in the observable Universe. Furthermore, we show that PIXIE can detect subtle relativistic effects in the sky-averaged TSZ signal at 30σ, which directly probe moments of the optical depth-weighted intracluster medium electron temperature distribution. These effects break the degeneracy between the electron density and the temperature in the mean TSZ signal, allowing a direct inference of the mean baryon density at low redshift. Future spectral distortion probes will thus determine the global thermodynamic properties of ionized gas in the Universe with unprecedented precision. These measurements will impose a fundamental "integral constraint" on models of galaxy formation and the injection of feedback energy over cosmic time.

  18. Improving quantum gate fidelities by using a qubit to measure microwave pulse distortions.

    Science.gov (United States)

    Gustavsson, Simon; Zwier, Olger; Bylander, Jonas; Yan, Fei; Yoshihara, Fumiki; Nakamura, Yasunobu; Orlando, Terry P; Oliver, William D

    2013-01-25

    We present a new method for determining pulse imperfections and improving the single-gate fidelity in a superconducting qubit. By applying consecutive positive and negative π pulses, we amplify the qubit evolution due to microwave pulse distortions, which causes the qubit state to rotate around an axis perpendicular to the intended rotation axis. Measuring these rotations as a function of pulse period allows us to reconstruct the shape of the microwave pulse arriving at the sample. Using the extracted response to predistort the input signal, we are able to reduce the average error per gate by 37%, which enables us to reach an average single-qubit gate fidelity higher than 0.998.

  19. Energy Dependence of the Intermodule Widening Correction

    CERN Document Server

    Mcblane, Neil Fraser

    2017-01-01

    This project looked to investigate the energy dependence of the ATLAS Liquid Argon (LAr) Calorimeter Intermodule Widening correction factors. A clear energy dependence was observed, with possible parameterisations of the dependency were briefly explored. In addition, official correction factors were validated on a new software release.

  20. Distinguishing different scenarios of early energy release with spectral distortions of the cosmic microwave background

    CERN Document Server

    Chluba, Jens

    2013-01-01

    Deviations of the cosmic microwave background (CMB) frequency spectrum from a pure blackbody tell an exciting story about the thermal history of our Universe. In this paper we show how well future CMB measurements could decipher this tale, envisioning a PIXIE-like spectrometer, which could improve the distortion constraints obtained with COBE/FIRAS some 20 years ago by at least three orders of magnitude. This opens a large discovery space, offering deep insights to particle and early-universe physics, opportunities that no longer should be left unexplored. Specifically, we consider scenarios with annihilating and decaying relic particles, as well as signatures from the dissipation of primordial small-scale power. PIXIE can potentially rule out different early-universe scenarios, and moreover will allow unambiguous detections in many of the considered cases, as we demonstrate here. We also discuss slightly more futuristic experiments, with several times improved sensitivities, to highlight the large potential ...

  1. The Distortion of the Cosmic Microwave Background by the Milky Way

    CERN Document Server

    Czaja, Benjamin

    2014-01-01

    The Milky Way can act as a large-scale weak gravitational lens of the cosmic microwave background (CMB). We study this effect using a photon ray-tracing code and a Galactic mass distribution with disk, bulge and halo components. For an observer at the Sun's coordinates in the Galaxy, the bending of CMB photon paths is limited to less than one arcsecond, and only for rays that pass within a few degrees of the Galactic Center. However, the entire sky is affected, resulting in global distortions of the CMB on large angular scales. These distortions can cause the low-order multipoles of a spherical harmonic expansion of the CMB sky temperature to leak into higher-order modes. Thus the component of the CMB dipole that results from the Local Group's motion relative to the local cosmic frame of rest contributes to higher-order moments for an observer in the solar system. With our ray-tracing code we show that the phenomenon is not sensitive to the specific choice of Galactic potential. We also quantitatively rule it...

  2. Constraining Primordial Black-Hole Bombs through Spectral Distortions of the Cosmic Microwave Background

    CERN Document Server

    Pani, Paolo

    2013-01-01

    We consider the imprint of superradiant instabilities of nonevaporating primordial black holes (PBHs) on the spectrum of the cosmic microwave background (CMB). In the radiation dominated era, PBHs are surrounded by a roughly homogeneous cosmic plasma which endows photons with an effective mass through the plasma frequency. In this setting, spinning PBHs are unstable to a spontaneous spindown through the well-known "black-hole bomb" mechanism. At linear level, the photon density is trapped by the effective photon mass and grows exponentially in time due to superradiance. As the plasma density declines due to cosmic expansion, the associated energy around PBHs is released and dissipated in the CMB. We evaluate the resulting spectral distortions of the CMB in the redshift range 10^3 < z < 2x10^6. Using the existing COBE/FIRAS bounds on CMB spectral distortions, we derive upper limits on the fraction of dark matter that can be associated with spinning PBHs in the mass range 10^{-8}*Msun < M < 0.2*Msin...

  3. Constraining primordial black-hole bombs through spectral distortions of the cosmic microwave background

    Science.gov (United States)

    Pani, Paolo; Loeb, Abraham

    2013-08-01

    We consider the imprint of super-radiant instabilities of nonevaporating primordial black holes (PBHs) on the spectrum of the cosmic microwave background (CMB). In the radiation-dominated era, PBHs are surrounded by a roughly homogeneous cosmic plasma which endows photons with an effective mass through the plasma frequency. In this setting, spinning PBHs are unstable to a spontaneous spindown through the well-known “black hole bomb” mechanism. At the linear level, the photon density is trapped by the effective photon mass and grows exponentially in time due to super-radiance. As the plasma density declines due to cosmic expansion, the associated energy around PBHs is released and dissipated in the CMB. We evaluate the resulting spectral distortions of the CMB in the redshift range 103≲z≲2×106. Using the existing COBE/FIRAS bounds on CMB spectral distortions, we derive upper limits on the fraction of dark matter that can be associated with spinning PBHs in the mass range 10-8M⊙≲M≲0.2M⊙. For maximally spinning PBHs, our limits are much tighter than those derived from microlensing or other methods. Future data from the proposed PIXIE mission could improve our limits by several orders of magnitude.

  4. Constraints on primordial black holes by distortions of the cosmic microwave background

    Science.gov (United States)

    Tashiro, Hiroyuki; Sugiyama, Naoshi

    2008-07-01

    The possible influence of primordial black hole (PBH) evaporations on cosmic microwave backgrounds (CMB) is investigated. The spectrum distortions of CMB from the blackbody spectrum are described by the chemical potential μ and the Compton parameter y. From COBE/FIRAS limits on μ and y, the power-law index n of primordial density fluctuations and the mass fraction of PBHs β are constrained by employing the peak theory for the formation process of PBHs. Constraints set here are n<1.304 and n<1.333 in the thresholds of peaks ζth=0.7 and ζth=1.2, respectively, for the PBH mass range between 2.7×1011g and 1.6×1012g, and n<1.312 and n<1.343 in the thresholds of peaks ζth=0.7 and ζth=1.2, respectively, for the PBH mass range between 1.6×1012g and 3.5×1013g, which correspond to the comoving scales between 3×10-18Mpc and 4×10-17Mpc. The constraint on the PBH fraction, which is the direct probe of the amplitude of density fluctuations on these scales, stays at almost the same value as β<10-21 in these mass ranges. It is also found that, with these constraints, UV photons injected by PBH evaporations are unlikely to ionize the majority of hydrogen atoms.

  5. Distinguishing different scenarios of early energy release with spectral distortions of the cosmic microwave background

    Science.gov (United States)

    Chluba, J.

    2013-12-01

    Deviations of the cosmic microwave background (CMB) frequency spectrum from a pure blackbody tell an exciting story about the thermal history of our Universe. In this paper, we illustrate how well future CMB measurements might decipher this tale, envisioning a PIXIE-like spectrometer, which could improve the distortion constraints obtained with COBE/FIRAS some 20 years ago by at least three orders of magnitude. This opens a large discovery space, offering deep insights to particle and early-universe physics, opportunities that no longer should be left unexplored. Specifically, we consider scenarios with annihilating and decaying relic particles, as well as signatures from the dissipation of primordial small-scale power. PIXIE can potentially rule out different early-universe scenarios and moreover will allow unambiguous detections in many of the considered cases, as we demonstrate here. We also discuss slightly more futuristic experiments, with several times improved sensitivities, to highlight the large potential of this new window to the pre-recombination universe.

  6. Constraints on Primordial Black Holes by Distortions of Cosmic Microwave Background

    CERN Document Server

    Tashiro, Hiroyuki

    2008-01-01

    Possible influence of primordial black hole (PBH) evaporations on cosmic microwave background (CMB) is investigated. The spectrum distortions of CMB from the black-body spectrum are described by the chemical potential $\\mu$ and the Compton parameter $y$. From COBE/FIRAS limits on $\\mu$ and $y$, the power law index $n$ of primordial density fluctuations and the mass fraction of PBHs $\\beta$ are constrained by employing the peak theory for the formation process of PBHs. Constraints set here are $n < 1.304$ and $n<1.333$ in the thresholds of peaks $\\zeta_{\\rm th} =0.7$ and $\\zeta_{\\rm th} =1.2$, respectively, for the PBH mass range between $2.7\\times 10^{11}$g and $1.6 \\times 10^{12}$g, and $n < 1.312$ and $n<1.343$ in the thresholds of peaks $\\zeta_{\\rm th} =0.7$ and $\\zeta_{\\rm th} =1.2$, respectively, for the PBH mass range between $1.6 \\times 10^{12} {\\rm g}$ and $3.5\\times 10^{13}$g, which correspond to the comoving scales between $3 \\times 10^{-18}$Mpc and $ 4\\times 10^{-17}$Mpc. The constraint...

  7. Large microwave phase shift and small distortion in an integrated waveguide device

    DEFF Research Database (Denmark)

    Öhman, Filip; Sales, Salvador; Chen, Yaohui;

    2007-01-01

    We have obtained a tunable phase shift of 150 degrees in an integrated semiconductor waveguide by optimizing the interplay of fast and slow light effects. Furthermore, the distortions imposed by device nonlinearities have been quantified....

  8. Distortion-free spectrum sliced microwave photonic signal processor: analysis, design and implementation.

    Science.gov (United States)

    Li, Liwei; Yi, Xiaoke; Huang, Thomas X H; Minasian, Robert A

    2012-05-01

    A new switchable microwave photonic filter based on a novel spectrum slicing technique is presented. The processor enables programmable multi-tap generation with general transfer function characteristics and offers tunability, reconfigurabiliy, and switchability. It is based on connecting a dispersion controlled spectrum slicing filter after the modulated bipolar broadband light source, which consequently generates multiple spectrum slices with bipolarity, and compensates dispersion induced RF degradation simultaneously within a single device. A detailed theoretical model for this microwave photonic filter design is presented. Experimental results are presented which verify the model, and demonstrate a 33 bipolar-tap microwave filter with significant reduction of passband attenuations at high frequencies. The RF response improvement of the new microwave photonic filter is investigated, for both an ideal linear group delay line and for the experimental fiber delay line that has second order group delay and the results show that this new structure is effective for RF filters with various free spectral range values and spectrum slice bandwidths. Finally, a switchable bipolar filter that has a square-top bandpass filter response with more than 30 dB stopband attenuation that can be switched on/off via software control is demonstrated.

  9. Carbon Nanotube Passive Intermodulation Device for Nonlinear Energy Harvesting

    Science.gov (United States)

    Lerner, Mitchell; Perez, Israel; Rockway, John

    2014-03-01

    The navy is interested in designing RF front-ends for receivers to handle high power jammers and other strong interferers. Instead of blocking that energy or dissipating it as heat in filters or amplifiers, this project investigates re-directing that energy for harvesting and storage. The approach is based on channelizing a high power jamming signal into a passive intermodulation device to create intermodulation products in sub-band frequencies, which could then be harvested for energy. The intermodulation device is fabricated using carbon nanotube transistors and such devices can be modified by creating chemical defects in the sidewalls of the nanotubes and locally gating the devices with a slowly varying electric field. These effects controllably enhance the hysteretic non-linearity in the transistors IV behavior. Combining these components with a RF energy harvester on the back-end should optimize the re-use of inbound jamming energy while maximizing the utility of standard back end radio components.

  10. 无线通信系统中三阶交调的研究%Research on the Third-Order Intermodulation in Wireless Communication System

    Institute of Scientific and Technical Information of China (English)

    谭庆艳; 庄剑

    2014-01-01

    With the rapid development of the communications industry, the demand for the information capacity in a fixed bandwidth in mobile communication is growing continuously. And passive intermodulation distortion, particularly the third order intermodulation, has a tremendous impact on the signal capacity. This paper focuses on the study of third-order intermodulation. First the influence of third-order intermodulation on communications is described, and then the impact of antenna-feeder system on third-order intermodulation performance is analyzed from both respects, production and construction. Finally the methods to avoid third-order intermodulation are presented.%随着通信行业的快速发展,移动通信对固定带宽内传输的信息容量的需求越来越大,而交调失真尤其是三阶交调,对信号容量以及接收灵敏度有着巨大的影响。文章主要对无线通信系统中三阶交调展开分析研究。首先阐述了三阶交调对通信产生的影响,然后分别从生产方面和施工方面着手分析了天馈系统对三阶交调性能的影响,最后介绍了避免三阶交调的一些方法。

  11. Microwave and Millimeter-Wave Signal Power Generation

    DEFF Research Database (Denmark)

    Hadziabdic, Dzenan

    Among the major limitations in high-speed communications and highresolution radars is the lack of efficient and powerful signal sources with low distortion. Microwave and millimeter-wave (mm-wave) signal power is needed for signal transmission. Progress in signal generation stems largely from...... the application of novel materials like galliumnitride (GaN) and silicon-carbide (SiC) and fabrication of indiumphosphide (InP) based transistors. One goal of this thesis is to assess GaN HEMT technology with respect to linear efficient signal power generation. While most reports on GaN HEMT high-power devices...... concentrate on single-tone performance, this study also encompasses two-tone intermodulation distortion measurements. An 8GHz two-stage power amplifier (PA) MMIC was developed. Harmonic tuning was performed to enhance the power-added efficiency (PAE). The transistors were biased in deep class-AB where low...

  12. Microwave field-efffect transistors theory, design, and application

    CERN Document Server

    Pengelly, Raymond

    1994-01-01

    This book covers the use of devices in microwave circuits and includes such topics as semiconductor theory and transistor performance, CAD considerations, intermodulation, noise figure, signal handling, S-parameter mapping, narrow- and broadband techniques, packaging and thermal considerations.

  13. A nonlinear equivalent circuit method for analysis of passive intermodulation of mesh reflectors

    Directory of Open Access Journals (Sweden)

    Jiang Jie

    2014-08-01

    Full Text Available Passive intermodulation (PIM has gradually become a serious electromagnetic interference due to the development of high-power and high-sensitivity RF/microwave communication systems, especially large deployable mesh reflector antennas. This paper proposes a field-circuit coupling method to analyze the PIM level of mesh reflectors. With the existence of many metal–metal (MM contacts in mesh reflectors, the contact nonlinearity becomes the main reason for PIM generation. To analyze these potential PIM sources, an equivalent circuit model including nonlinear components is constructed to model a single MM contact so that the transient current through the MM contact point induced by incident electromagnetic waves can be calculated. Taking the electric current as a new electromagnetic wave source, the far-field scattering can be obtained by the use of electromagnetic numerical methods or the communication link method. Finally, a comparison between simulation and experimental results is illustrated to verify the validity of the proposed method.

  14. Performance of MF-MSK Systems with Pre-distortion Schemes

    CERN Document Server

    Gergis, Labib Francis

    2011-01-01

    Efficient RF power amplifiers used in third generation systems require linearization in order to reduce adjacent channel inter-modulation distortion, without sacrificing efficiency. Digital baseband predistortion is a highly cost-effective way to linearize power amplifiers (PAs). New communications services have created a demand for highly linear high power amplifiers (HPA's). Traveling Wave Tubes Amplifiers (TWTA) continue to offer the best microwave HPA performance in terms of power efficiency, size and cost, but lag behind Solid State Power Amplifiers (SSAP's) in linearity. This paper presents a technique for improving TWTA linearity. The use of predistorter (PD) linearization technique is described to provide TWTA performance comparable or superior to conventional SSPA's. The characteristics of the PD scheme is derived based on the extension of Saleh's model for HPA. The analysis results of Multi-frequency Minimum Shift Keying (MF-MSK) in non-linear channels are presented in this paper.

  15. On intermodulation beams of satellite DBF transmitting multibeam array antenna

    Science.gov (United States)

    Zhao, Hongmei; Wang, Huali; Mu, Shanxiang

    2007-11-01

    Digital beamforming (DBF) transmitting multibeam planar array antenna with nonlinear behaviors of solid-state power amplifiers (SSPA) is discussed. This paper investigates the intermodulation beams produced by the nonlinearity characteristics of the SSPA with multiple carrier components. The Shimbo model is simplified to describe the nonlinear behaviors of SSPA. The optimal SSPA input back-off (IBO) point which is given the desired the carrier and the intermodulatin ratio (C/IM) is simulated. And the tradeoffs between linearity and efficiency of the power amplifier which influence this IBO is also discussed, helping to selecting suitable SSPA device and reducing the dc power consumption in satellite array antenna system.

  16. Package and PCB Effects Shift Intermodulation Notch in an RF Common-Emitter Amplifier

    Directory of Open Access Journals (Sweden)

    J.-M. Wu

    2014-04-01

    Full Text Available A Taylor series analysis is conducted to study the effects of the package and printed circuit board (PCB on the intermodulation nulling of an RF common-emitter amplifier. The equivalent parasitic element of the package and PCB interconnects is extracted from the impedance and admittance parameters, which are obtained using a three-dimensional (3-D electromagnetic simulation tool. The theoretical analysis reveals that the effects of the package and PCB on the intermodulation nulling of common-emitter amplifiers is to shift the intermodulation notch; that the third-order intermodulation (IM3 products under an original bias condition cannot be suppressed and that the linearity of common-emitter amplifiers is thereby degraded. A comparison between theory and simulation reveals good agreement in the predicted locations of the intermodulation notch in the absence and presence of a package and PCB.

  17. Large Signal Modulation and Distortion in a Microwave Phase Shifter Based on Slow Light in a Semiconductor Waveguide

    DEFF Research Database (Denmark)

    Chen, Yaohui; Öhman, Filip; Mørk, Jesper

    2006-01-01

    We model slow/light propagation in an active semiconductor waveguide in the large modulation depth regime. Distortion from higher harmonics is countered by filtering and the regenerating properties of the device further increase the modulation depth.......We model slow/light propagation in an active semiconductor waveguide in the large modulation depth regime. Distortion from higher harmonics is countered by filtering and the regenerating properties of the device further increase the modulation depth....

  18. Constraining primordial magnetic fields with distortions of the black-body spectrum of the cosmic microwave background: pre- and post-decoupling contributions

    Science.gov (United States)

    Kunze, Kerstin E.; Komatsu, Eiichiro

    2014-01-01

    Primordial magnetic fields that exist before the photon-baryon decoupling epoch are damped on length scales below the photon diffusion and free-streaming scales. The energy injected into the plasma by dissipation of magnetosonic and Alfv&aposen waves heats photons, creating a y-type distortion of the black-body spectrum of the cosmic microwave background. This y-type distortion is converted into a μ-type distortion when elastic Compton scattering is efficient. Therefore, we can use observational limits on y- and μ-type distortions to constrain properties of magnetic fields in the early universe. Assuming a Gaussian, random, and non-helical field, we calculate μ and y as a function of the present-day strength of the field, B0, smoothed over a certain Gaussian width, kc-1, as well as of the spectral index of the power spectrum of fields, nB, defined by PB(k)proptoknB. For a nearly scale-invariant spectrum with nB = -2.9 and a Gaussian smoothing width of kc-1 = 1Mpc, the existing COBE/FIRAS limit on μ yields B0 FIRAS limit on μ excludes a wide range of spectral indices given by nB > -2.6. After decoupling, energy dissipation is due to ambipolar diffusion and decaying MHD turbulence, creating a y-type distortion. The distortion is completely dominated by decaying MHD turbulence, and is of order y ≈ 10-7 for a few nG field smoothed over the damping scale at the decoupling epoch, kd, dec ≈ 290(B0/1nG)-1Mpc-1. The projected PIXIE limit on y would exclude B0 > 1.0 and 0.6 nG for nB = -2.9 and -2.3, respectively, and B0 > 0.6 nG for nB >= 2. Finally, we find that the current limits on the optical depth to Thomson scattering restrict the predicted y-type distortion to be ylesssim10-8.

  19. Third-order Intermodulation Reduction in Mobile Power Amplifiers by the First Stage Bias Control

    Directory of Open Access Journals (Sweden)

    J. H. Jung

    2012-06-01

    Full Text Available In this paper, the third order intermodulation distortion (IMD3 of three-stage power amplifier (PA is analyzed using the Volterra series. The analysis explains how the total IMD3 of the three-stage power amplifier can be reduced by the first-stage bias condition. The three-stage PA, which is fabricated using InGaP/GaAs hetero-junction bipolar transistor (HBT, operates with an optimized first driver stage bias for higher P1dB and good gain flatness. The power amplifier has been designed for 1626.5 MHz~1660.5 MHz satellite mobile communications. With π/4 DQPSK modulation signals, this PA can deliver a highly linear output power of 33 dBm from 3.6V supply voltage. At 33 dBm output power, it shows a gain of 31.9 dB, a power-added efficiency (PAE of 39.8%, an adjacent channel power ratio (ACPR of -28.2 dBc at a 31.25 KHz offset frequency.

  20. Remote manual operator for space station intermodule ventilation valve

    Science.gov (United States)

    Guyaux, James R.

    1996-01-01

    The Remote Manual Operator (RMO) is a mechanism used for manual operation of the Space Station Intermodule Ventilation (IMV) valve and for visual indication of valve position. The IMV is a butterfly-type valve, located in the ventilation or air circulation ducts of the Space Station, and is used to interconnect or isolate the various compartments. The IMV valve is normally operated by an electric motor-driven actuator under computer or astronaut control, but it can also be operated manually with the RMO. The IMV valve RMO consists of a handle with a deployment linkage, a gear-driven flexible shaft, and a linkage to disengage the electric motor actuator during manual operation. It also provides visual indication of valve position. The IMV valve RMO is currently being prepared for qualification testing.

  1. A joint study of early and late spectral distortions of the cosmic microwave background and of the millimetric foreground

    CERN Document Server

    Salvaterra, R

    2002-01-01

    We have compared the absolute temperature data of the CMB spectrum with models for CMB spectra distorted by a single or two heating processes at different cosmic times. The constraints on the fractional energy injected in the radiation field, DE/E, are mainly provided by the FIRAS instrument aboard the COBE satellite. Under the hypothesis that two heating processes have occurred at different epochs, the limits on DE/E are relaxed by a factor 2 both for the earlier and the later process with respect to the case in which a single energy injection in the thermal history of the universe is considered. In general, the constraints on DE/E are weaker for early processes than for relatively late processes, because of the wavelength coverage of FIRAS data. We considered also the FIRAS calibration as revised by Battistelli et al. 2000, that, in the case of the favourite calibrator emissivity law proposed by the authors, implies significant deviations from a planckian spectrum. An astrophysical explanation of this, alth...

  2. Frequency division multiplexed microwave and baseband digital optical fiber link for phased array antennas

    Science.gov (United States)

    Heim, Peter J.; McClay, C. Phillip

    1990-05-01

    A frequency-division multiplexed optical fiber link is described in which microwave (1-8 GHz) and baseband digital (1-10 Mb/s) signals are combined electrically and transmitted through a direct-modulation microwave optical link. The microwave signal does not affect bit error rate (BER) performance of the Manchester-coded baseband digital data link. The baseband digital signal affects microwave signal quality by generating second-order intermodulation noise. The intermodulation noise power density is found to be proportional to both the microwave input power and the digital input power, enabling the system to be modeled as a mixer (AM modulator). The conversion loss for the digital signal is approximately 68 dB for a 1-GHz microwave signal and is highly dependent on the microwave frequency, reaching a minimum value of 41 dB at 4.5 GHz, corresponding to the laser diode relaxation oscillation frequency. It is shown that Manchester coding on the digital link places the intermodulation noise peak away from the microwave signal, preventing degradation of close-carrier phase noise (<1 kHz offset). A direct trade-off between intermodulation noise and digital link margin is developed to project system performance.

  3. Nonlinearity characterization of temperature sensing systems for integrated circuit testing by intermodulation products monitoring.

    Science.gov (United States)

    Altet, J; Mateo, D; Perpiñà, X; Grauby, S; Dilhaire, S; Jordà, X

    2011-09-01

    This work presents an alternative characterization strategy to quantify the nonlinear behavior of temperature sensing systems. The proposed approach relies on measuring the temperature under thermal sinusoidal steady state and observing the intermodulation products that are generated within the sensing system itself due to its nonlinear temperature-output voltage characteristics. From such intermodulation products, second-order interception points can be calculated as a figure of merit of the measuring system nonlinear behavior. In this scenario, the present work first shows a theoretical analysis. Second, it reports the experimental results obtained with three thermal sensing techniques used in integrated circuits.

  4. Intermodulation Linearity in High-k/Metal Gate 28 nm RF CMOS Transistors

    Directory of Open Access Journals (Sweden)

    Zhen Li

    2015-09-01

    Full Text Available This paper presents experimental characterization, simulation, and Volterra series based analysis of intermodulation linearity on a high-k/metal gate 28 nm RF CMOS technology. A figure-of-merit is proposed to account for both VGS and VDS nonlinearity, and extracted from frequency dependence of measured IIP3. Implications to biasing current and voltage optimization for linearity are discussed.

  5. Microwave materials for wireless applications

    CERN Document Server

    Cruickshank, David B

    2011-01-01

    This practical resource offers you an in-depth, up-to-date understanding of the use of microwave magnetic materials for cutting-edge wireless applications. The book discusses device applications used in wireless infrastructure base stations, point-to-point radio links, and a range of more specialized microwave systems. You find detailed discussions on the attributes of each family of magnetic materials with respect to specific wireless applications. Moreover, the book addresses two of the hottest topics in the field today - insertion loss and intermodulation. This comprehensive reference also

  6. A novel stimulation method for multi-class SSVEP-BCI using intermodulation frequencies

    Science.gov (United States)

    Chen, Xiaogang; Wang, Yijun; Zhang, Shangen; Gao, Shangkai; Hu, Yong; Gao, Xiaorong

    2017-04-01

    Objective. Steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) has been widely investigated because of its easy system configuration, high information transfer rate (ITR) and little user training. However, due to the limitations of brain responses and the refresh rate of a monitor, the available stimulation frequencies for practical BCI application are generally restricted. Approach. This study introduced a novel stimulation method using intermodulation frequencies for SSVEP-BCIs that had targets flickering at the same frequency but with different additional modulation frequencies. The additional modulation frequencies were generated on the basis of choosing desired flickering frequencies. The conventional frame-based ‘on/off’ stimulation method was used to realize the desired flickering frequencies. All visual stimulation was present on a conventional LCD screen. A 9-target SSVEP-BCI based on intermodulation frequencies was implemented for performance evaluation. To optimize the stimulation design, three approaches (C: chromatic; L: luminance; CL: chromatic and luminance) were evaluated by online testing and offline analysis. Main results. SSVEP-BCIs with different paradigms (C, L, and CL) enabled us not only to encode more targets, but also to reliably evoke intermodulation frequencies. The online accuracies for the three paradigms were 91.67% (C), 93.98% (L), and 96.41% (CL). The CL condition achieved the highest classification performance. Significance. These results demonstrated the efficacy of three approaches (C, L, and CL) for eliciting intermodulation frequencies for multi-class SSVEP-BCIs. The combination of chromatic and luminance characteristics of the visual stimuli is the most efficient way for the intermodulation frequency coding method.

  7. Real time and in situ determination of ammonia concentration in the atmosphere by intermodulated Stark resonant CO2 laser spectroscopy.

    NARCIS (Netherlands)

    Sauren, H.; Gerkema, E.; Bicanic, D.; Jalink, H.

    1993-01-01

    A concept of Intermodulated Photoacoustic Stark Spectroscopy (IMPASS) was used in an attempt to perform the interference-free field measurement of trace ammonia (3-40 ppbv) concentration levels in the air with a time resolution of 40 s.

  8. Compensating the distortion of micro-speakers in a closed box with consideration of nonlinear mechanical resistance.

    Science.gov (United States)

    Hu, Yuxiang; Wang, Min; Lu, Jing; Qiu, Xiaojun

    2017-02-01

    For micro-speakers in a closed box, commonly used nonlinear compensation methods only compensate the distortion caused by the force factor and the stiffness. In this letter, a method to compensate the distortion with consideration of the nonlinear mechanical resistance is proposed based on the feedback linearization criterion. The proposed method is further improved by minimizing the variation of the output power spectrum after compensation. The simulations and experiments show that the total harmonic distortion and the intermodulation distortion of the sound pressure can be reduced significantly with little influence on the sound pressure level.

  9. Towards a Carbon Nanotube Intermodulation Product Sensor for Nonlinear Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Mitchell B. Lerner

    2015-01-01

    Full Text Available It is critically important in designing RF receiver front ends to handle high power jammers and other strong interferers. Instead of blocking incoming energy or dissipating it as heat, we investigate the possibility of redirecting that energy for harvesting and storage. The approach is based on channelizing a high power signal into a previously unknown circuit element which serves as a passive intermodulation device. This intermodulation component must produce a hysteretic current-voltage curve to be useful as an energy harvester. Here we demonstrate a method by which carbon nanotube transistors produce the necessary hysteretic I-V curves. Such devices can be tailored to the desired frequency by introducing functional groups to the nanotubes. These effects controllably enhance the desired behavior, namely, hysteretic nonlinearity in the transistors’ I-V characteristic. Combining these components with an RF energy harvester may one day enable the reuse of inbound jamming energy for standard back end radio components.

  10. Analytical model and figures of merit for filtered Microwave Photonic Links.

    Science.gov (United States)

    Gasulla, Ivana; Capmany, José

    2011-09-26

    The concept of filtered Microwave Photonic Links is proposed in order to provide the most general and versatile description of complex analog photonic systems. We develop a field propagation model where a global optical filter, characterized by its optical transfer function, embraces all the intermediate optical components in a linear link. We assume a non-monochromatic light source characterized by an arbitrary spectral distribution which has a finite linewidth spectrum and consider both intensity modulation and phase modulation with balanced and single detection. Expressions leading to the computation of the main figures of merit concerning the link gain, noise and intermodulation distortion are provided which, to our knowledge, are not available in the literature. The usefulness of this derivation resides in the capability to directly provide performance criteria results for complex links just by substituting in the overall closed-form formulas the numerical or measured optical transfer function characterizing the link. This theory is presented thus as a potential tool for a wide range of relevant microwave photonic application cases which is extendable to multiport radio over fiber systems.

  11. Molecular structure and centrifugal distortion in methylthioethyne

    NARCIS (Netherlands)

    Engelsen, D. den

    1969-01-01

    The investigation of the microwave spectra of five isotopic species of methylthioethyne, HCCSCH3 enabled a fairly reliable calculation to be made of bond lengths and angles. The centrifugal distortion parameters are related to molecular vibrations.

  12. CMB distortions from superconducting cosmic strings

    Science.gov (United States)

    Tashiro, Hiroyuki; Sabancilar, Eray; Vachaspati, Tanmay

    2012-05-01

    We reconsider the effect of electromagnetic radiation from superconducting strings on cosmic microwave background μ and y distortions and derive present (COBE-FIRAS) and future (PIXIE) constraints on the string tension, μs, and electric current, I. We show that absence of distortions of the cosmic microwave background in PIXIE will impose strong constraints on μs and I, leaving the possibility of light strings (Gμs≲10-18) or relatively weak currents (I≲10TeV).

  13. Constraining primordial magnetic fields with distortions of the black-body spectrum of the cosmic microwave background: pre- and post-decoupling contributions

    CERN Document Server

    Kunze, Kerstin E

    2014-01-01

    Observational limits on $y$- and $\\mu$-type distortions can constrain properties of magnetic fields in the early universe. For a Gaussian, random, and non-helical field, $\\mu$ and $y$ are calculated a function of the present-day strength of the field, $B_0$, smoothed over a certain Gaussian width, $k_c^{-1}$, and spectral index, $n_B$, defined by $P_B(k)\\propto k^{n_B}$. For $n_B=-2.9$ and $k_c^{-1}=1 {\\rm Mpc}$, the COBE/FIRAS limit on $\\mu$ yields $B_0-2.6$. After decoupling, energy dissipation is due to ambipolar diffusion and decaying MHD turbulence, creating a $y$-type distortion. The distortion is completely dominated by decaying MHD turbulence, and is of order $y\\approx 10^{-7}$ for a few nG field smoothed over the damping scale at the decoupling epoch, $k_{d,dec}\\approx 290 (B_0/1 {\\rm nG})^{-1} {\\rm Mpc}^{-1}$. This contribution is as large as those of the known contributions such as reionization and virialized objects at lower redshifts. The projected PIXIE limit on $y$ would exclude $B_0>1.0$ and 0...

  14. The Impact of Inter-Modulation Components on Interferometric GNSS-Reflectometry

    Directory of Open Access Journals (Sweden)

    Weiqiang Li

    2016-12-01

    Full Text Available The interferometric Global Navigation Satellite System Reflectometry (iGNSS-R exploits the full spectrum of the transmitted GNSS signal to improve the ranging performance for sea surface height applications. The Inter-Modulation (IM component of the GNSS signals is an additional component that keeps the power envelope of the composite signals constant. This extra component has been neglected in previous studies on iGNSS-R, in both modelling and instrumentation. This letter takes the GPS L1 signal as an example to analyse the impact of the IM component on iGNSS-R ocean altimetry, including signal-to-noise ratio, the altimetric sensitivity and the final altimetric precision. Analytical results show that previous estimates of the final altimetric precision were underestimated by a factor of 1 . 5 ∼ 1 . 7 due to the negligence of the IM component, which should be taken into account in proper design of the future spaceborne iGNSS-R altimetry missions.

  15. High performance guard ring P-i-N photodetectors for microwave subcarrier wavelength division multiplexed networks

    Science.gov (United States)

    Odubanjo, Babatunde A.

    This dissertation is concerned with the design and fabrication of high performance guard ring photodetectors suitable for use in very dense WDM microwave subcarrier multiplexed (SCM) networks and Passive Optical Networks (PONs). Two issues are addressed. The first obvious quantity of concern is the problem of nonlinearity distortion characteristics of the detector arising from- internal electric field perturbation due to space charge and external loading induced effects-intermodulation effects due to the mixing between different microwave subcarriers-and optical beat notes interference issue. The second is the problem of slower responses due to diffusion currents. Our investigation begins with an analytic study of the transient response of a typical p-i-n and avalanche photodetectors (APDs) to determine the origin of their nonlinearities and slow response and their suitability for use in a narrow-band receiver required for SCM networks. We found that for a single channel link where the total receiver photocurrent is of the same magnitude as the signal photocurrent, avalanche photodetectors can dramatically increase receiver sensitivity. However in microwave subcarrier multiplexed networks the photodiodes in each receiver detect all subcarrier channels therefore the total received photocurrent is greater than that of a single channel by many orders. Thus under these criteria, APDs cannot provide any improvement in the receiver sensitivity. In fact avalanche gain noise mechanism degrades the expected S/N ratio due to its intrinsic excess noise factor. Furthermore, APDs typically require large bias voltage. There is also the problem of limited gain-bandwidth product which makes avalanche photodetectors unsuitable for very dense WDM networks. The clear choice for SCM-based networks is therefore the p-i-n photodiode which is shot-noise limited in high speed applications. We use our analysis to optimize a typical p-i-n photodiode. The result is a novel guard ring

  16. PERFORMANCE IMPROVEMENT FOR A WCDMA RADIO OVER FIBER SYSTEM USING DIGITAL PRE-DISTORTER

    Institute of Scientific and Technical Information of China (English)

    Ying Xiangyue; Xu Tiefeng; Liu Taijun; Nie Qiuhua

    2012-01-01

    In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF link so as to suppress the out-of-band spurious spectrum and improve the transmission performance.The experimental results show that the out-of-band emission due to existence of the third-order Inter-Modulation Distortion (IMD3) is obviously suppressed by these two DPD.An Adjacent Channel Power Ratio (ACPR) improvement of 8 dB is obtained for a single-carrier WCDMA signal transmission.These two DPD have equal ability in linearization of the ROF system for a three-carrier WCDMA signal transmission.There is no apparent memory effects exist in the ROF link.

  17. CMB Distortions from Superconducting Cosmic Strings

    CERN Document Server

    Tashiro, Hiroyuki; Vachaspati, Tanmay

    2012-01-01

    We reconsider the effect of electromagnetic radiation from superconducting strings on cosmic microwave background (CMB) mu- and y-distortions and derive present (COBE-FIRAS) and future (PIXIE) constraints on the string tension, mu_s, and electric current, I. We show that absence of distortions of the CMB in PIXIE will impose strong constraints on mu_s and I, leaving the possibility of light strings (G mu_s < 10^{-18}) or relatively weak currents (I < 10 TeV).

  18. CMB spectral distortion constraints on thermal inflation

    Science.gov (United States)

    Cho, Kihyun; Hong, Sungwook E.; Stewart, Ewan D.; Zoe, Heeseung

    2017-08-01

    Thermal inflation is a second epoch of exponential expansion at typical energy scales V1/4 ~ 106 ~ 8 GeV. If the usual primordial inflation is followed by thermal inflation, the primordial power spectrum is only modestly redshifted on large scales, but strongly suppressed on scales smaller than the horizon size at the beginning of thermal inflation, k > kb = ab Hb. We calculate the spectral distortion of the cosmic microwave background generated by the dissipation of acoustic waves in this context. For kb ll 103 Mpc-1, thermal inflation results in a large suppression of the μ-distortion amplitude, predicting that it falls well below the standard value of μ simeq 2× 10-8. Thus, future spectral distortion experiments, similar to PIXIE, can place new limits on the thermal inflation scenario, constraining kb gtrsim 103 Mpc-1 if μ simeq 2× 10-8 were found.

  19. Thermal distortion test facility

    Science.gov (United States)

    Stapp, James L.

    1995-02-01

    The thermal distortion test facility (TDTF) at Phillips Laboratory provides precise measurements of the distortion of mirrors that occurs when their surfaces are heated. The TDTF has been used for several years to evaluate mirrors being developed for high-power lasers. The facility has recently undergone some significant upgrades to improve the accuracy with which mirrors can be heated and the resulting distortion measured. The facility and its associated instrumentation are discussed.

  20. Which spectral distortions does $\\Lambda$CDM actually predict?

    CERN Document Server

    Chluba, Jens

    2016-01-01

    Ever refined cosmological measurements have established the $\\Lambda$CDM concordance model, with the key cosmological parameters being determined to percent-level precision today. This allows us to make explicit predictions for the spectral distortions of the cosmic microwave background (CMB) created by various processes occurring in the early Universe. Here, we summarize all guaranteed CMB distortions and assess their total uncertainty within $\\Lambda$CDM. We also compare simple methods for approximating them, highlighting some of the subtle aspects when it comes to interpreting future distortion measurements. Under simplified assumptions, we briefly study how well a PIXIE-like experiment may measure the main distortion parameters (i.e., $\\mu$ and $y$). Next generation CMB spectrometers are expected to detect the distortion caused by reionization and structure formation at extremely high significance. They will also be able to constrain the small-scale power spectrum through the associated $\\mu$-distortion, ...

  1. Distortion Control during Welding

    NARCIS (Netherlands)

    Akbari Pazooki, A.M.

    2014-01-01

    The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ met

  2. Universal Sampling Rate Distortion

    OpenAIRE

    Boda, Vinay Praneeth; Narayan, Prakash

    2017-01-01

    We examine the coordinated and universal rate-efficient sampling of a subset of correlated discrete memoryless sources followed by lossy compression of the sampled sources. The goal is to reconstruct a predesignated subset of sources within a specified level of distortion. The combined sampling mechanism and rate distortion code are universal in that they are devised to perform robustly without exact knowledge of the underlying joint probability distribution of the sources. In Bayesian as wel...

  3. Spherical Redshift Distortions

    OpenAIRE

    1995-01-01

    Peculiar velocities induce apparent line of sight displacements of galaxies in redshift space, distorting the pattern of clustering in the radial versus transverse directions. On large scales, the amplitude of the distortion yields a measure of the dimensionless linear growth rate $\\beta \\approx \\Omega^{0.6}/b$, where $\\Omega$ is the cosmological density and $b$ the linear bias factor. To make the maximum statistical use of the data in a wide angle redshift survey, and for the greatest accura...

  4. Spectral Distortion in a Radially Inhomogeneous Cosmology

    CERN Document Server

    Caldwell, R R

    2013-01-01

    The spectral distortion of the cosmic microwave background blackbody spectrum in a radially inhomogeneous spacetime, designed to exactly reproduce a LambdaCDM expansion history along the past light cone, is shown to exceed the upper bound established by COBE-FIRAS by a factor of approximately 3000. This simple observational test helps uncover a slew of pathological features that lie hidden inside the past light cone, including a radially contracting phase at decoupling and, if followed to its logical extreme, a naked singularity at the radially inhomogeneous Big Bang.

  5. Spectral distortion in a radially inhomogeneous cosmology

    Science.gov (United States)

    Caldwell, R. R.; Maksimova, N. A.

    2013-11-01

    The spectral distortion of the cosmic microwave background blackbody spectrum in a radially inhomogeneous space-time, designed to exactly reproduce a ΛCDM expansion history along the past light cone, is shown to exceed the upper bound established by COBE-FIRAS by a factor of approximately 3700. This simple observational test helps uncover a slew of pathological features that lie hidden inside the past light cone, including a radially contracting phase at decoupling and, if followed to its logical extreme, a naked singularity at the radially inhomogeneous big bang.

  6. Microwave engineering

    CERN Document Server

    Pozar, David M

    2012-01-01

    The 4th edition of this classic text provides a thorough coverage of RF and microwave engineering concepts, starting from fundamental principles of electrical engineering, with applications to microwave circuits and devices of practical importance.  Coverage includes microwave network analysis, impedance matching, directional couplers and hybrids, microwave filters, ferrite devices, noise, nonlinear effects, and the design of microwave oscillators, amplifiers, and mixers. Material on microwave and RF systems includes wireless communications, radar, radiometry, and radiation hazards. A large

  7. The distorted tropane of scopoline.

    Science.gov (United States)

    Écija, Patricia; Cocinero, Emilio J; Lesarri, Alberto; Basterretxea, Francisco J; Fernández, José A; Castaño, Fernando

    2013-06-24

    The structural isomerization of scopine into scopoline (oscine) has been observed in a supersonic jet expansion using microwave spectroscopy. The rotational spectrum evidences a single structure in the gas phase, providing a first description of the (three-ring) structurally distorted tropane in scopoline. The absence of rotational signatures of any scopine conformation suggests a practically quantitative isomerization at the vaporization temperatures of the experiment (ca. 90 °C). The determined rotational parameters of scopoline reveal the structural consequences of the intramolecular cyclation of scopine, which breaks the original epoxy group and creates a new ether bridge and a 7β-hydroxytropane configuration. The hydroxy group further stabilizes the molecule by an O-H⋅⋅⋅N intramolecular hydrogen bond, which, in turn, forces the N-methyl group to the less stable axial form. Supporting ab initio (MP2) and DFT (B3LYP, M06-2X) calculations are included. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Distortion dependent intersystem crossing

    DEFF Research Database (Denmark)

    Stephansen, Anne Boutrup; Sølling, Theis Ivan

    2017-01-01

    The competition between ultrafast intersystem crossing and internal conversion in benzene, toluene, and p-xylene is investigated with time-resolved photoelectron spectroscopy and quantum chemical calculations. By exciting to S2 out-of-plane symmetry breaking, distortions are activated at early ti...

  9. Probing early-universe phase transitions with CMB spectral distortions

    Science.gov (United States)

    Amin, Mustafa A.; Grin, Daniel

    2014-10-01

    Global, symmetry-breaking phase transitions in the early universe can generate scaling seed networks which lead to metric perturbations. The acoustic waves in the photon-baryon plasma sourced by these metric perturbations, when Silk damped, generate spectral distortions of the cosmic microwave background (CMB). In this work, the chemical potential distortion (μ ) due to scaling seed networks is computed and the accompanying Compton y -type distortion is estimated. The specific model of choice is the O (N ) nonlinear σ -model for N ≫1 , but the results remain the same order of magnitude for other scaling seeds. If CMB anisotropy constraints to the O (N ) model are saturated, the resulting chemical potential distortion μ ≲2 ×1 0-9 .

  10. Probing early-universe phase transitions with CMB spectral distortions

    CERN Document Server

    Amin, Mustafa A

    2014-01-01

    Global, symmetry-breaking phase transitions in the early universe can generate scaling seed networks which lead to metric perturbations. The acoustic waves in the photon-baryon plasma sourced by these metric perturbations, when Silk damped, generate spectral distortions of the cosmic microwave background (CMB). In this work, the chemical potential distortion ($\\mu$) due to scaling seed networks is computed and the accompanying Compton $y$-type distortion is estimated. The specific model of choice is the $O(N)$ nonlinear $\\sigma$-model for $N\\gg 1$, but the results remain the same order of magnitude for other scaling seeds. If CMB anisotropy constraints to the $O(N)$ model are saturated, the resulting chemical potential distortion $\\mu \\lesssim 2\\times 10^{-9}$.

  11. CMB spectral distortions as solutions to the Boltzmann equations

    CERN Document Server

    Ota, Atsuhisa

    2016-01-01

    We newly re-interpret cosmic microwave background spectral distortions as solutions to the Boltzmann equation at second order. This approach makes it possible to solve the equation of the momentum dependent temperature perturbations explicitly. In addition, we define higher order spectral distortions systematically, assuming that the collision term is linear in the photon distribution functions. For example, we find the linear Sunyaev-Zel'dovich effect whose momentum shape is different from the usual $y$ distortion, and show that the higher order spectral distortions are also generated as a result of the diffusion process in a language of higher order Boltzmann equations. The method may be applicable to a wider class of problems and has potential to give a general prescription to non-equilibrium physics.

  12. Microwave Ovens

    Science.gov (United States)

    ... ovens heat food using microwaves, a form of electromagnetic radiation similar to radio waves. Microwaves have three characteristics ... that their microwave oven products meet the strict radiation safety standard ... if your microwave oven has damage to its door hinges, latches, or seals, or ...

  13. Microwave imaging

    CERN Document Server

    Pastorino, Matteo

    2010-01-01

    An introduction to the most relevant theoretical and algorithmic aspects of modern microwave imaging approaches Microwave imaging-a technique used in sensing a given scene by means of interrogating microwaves-has recently proven its usefulness in providing excellent diagnostic capabilities in several areas, including civil and industrial engineering, nondestructive testing and evaluation, geophysical prospecting, and biomedical engineering. Microwave Imaging offers comprehensive descriptions of the most important techniques so far proposed for short-range microwave imaging-in

  14. Research on Intermodulation Interference Between 2.3G TD-LTE and China Unicom WCDMA Systems%2.3G TD-LTE和联通WCDMA系统合路互调干扰问题研究

    Institute of Scientific and Technical Information of China (English)

    郭希蕊; 张涛

    2015-01-01

    Inter-system interference between 2.3G TD-LTE and China Unicom WCDMA systems was analyzed ifrstly. Then, third-order intermodulation interference was theoretically analyzed and calculated and laboratory test results of intermodulation interference were analyzed in depth. Finally, the solution to intermodulation interference which combines high-performance device with general device was presented.%首先对联通WCDMA与2.3G TD-LTE系统合路的系统间干扰进行分析;然后对三阶互调干扰进行理论分析及计算,并详细分析互调干扰实验室测试结果;最后提出了高性能器件与一般器件相结合的互调干扰问题解决方案。

  15. Evolution of CMB spectral distortion anisotropies and tests of primordial non-Gaussianity

    CERN Document Server

    Chluba, Jens; Amin, Mustafa A; Kamionkowski, Marc

    2016-01-01

    Anisotropies in distortions to the frequency spectrum of the cosmic microwave background (CMB) can be created through spatially varying heating processes in the early Universe. For instance, the dissipation of small-scale acoustic modes does create distortion anisotropies, in particular for non-Gaussian primordial perturbations. In this work, we derive approximations that allow describing the associated distortion field. We provide a systematic formulation of the problem using Fourier-space window functions, clarifying and generalizing previous approximations. Our expressions highlight the fact that the amplitudes of the spectral-distortion fluctuations induced by non-Gaussianity depend also on the homogeneous value of those distortions. Absolute measurements are thus required to obtain model-independent distortion constraints on primordial non-Gaussianity. We also include a simple description for the evolution of distortions through photon diffusion, showing that these corrections can usually be neglected. O...

  16. Optimization of Optically Preamplified Inter-Satellite Microwave Photonics Links with Two Radio-Frequency Signals Input%两路输入前置光放大星间微波光子链路优化

    Institute of Scientific and Technical Information of China (English)

    朱子行; 赵尚弘; 赵辉; 李勇军; 楚兴春; 蒋炜; 侯睿; 王翔; 赵顾颢

    2013-01-01

    考虑到星间微波光子链路传输损耗大且多路微波信号之间交调干扰严重,利用前置光放大来提高链路的信号噪声失真比RSNDR.建立了两路输入前置光放大星间微波光子链路模型,推导出了RSNDR的解析表达式.通过优化马赫-曾德尔调制器的直流偏置相移,使得在给定输入射频信号功率条件下RSNDR最大,并进一步分析了前置光放大器参数对最优直流偏置相移和RSNDR的影响.仿真结果表明,前置光放大改变了影响RSNDR的主要因素,使信号放大的倍数大于噪声和三阶交调(IM3)放大的倍数,从而提高了链路的RSNDR.当前置光放大器增益为20 dB、噪声系数为3 dB时,最优的RSNDR比不加前置光放大器时提高24 dB.前置光放大器增益和噪声系数对最优的RSNDR影响很大,而对最优的直流偏置相移几乎无影响.%An optical preamplifier is utilized to improve the signal-to-noise and distortion ratio .RSNDR of inter-satellite microwave photonics links considering the large signal losses in distant propagation and serious deterioration caused by inter-modulation distortion. An optically preamplified inter-satellite microwave photonics links model with two radio-frequency (RF) signals input is established and an analytical expression of .RSNDR is derived. The direct current (DC) bias phase shift of modulator can be optimized so as to maximize the .RSNDR given the desired input RF signal power, and the effects of the optical preamplifier parameters on the optimum DC bias phase shift and .RSNDR are also examined. Simulation results show that the most limitative factors degrading the .RSNDR are changed, and the fundamental power is seen to increase more compared with the power of third-order intermodulation (IM3) plus noise due to optical preamplifier. Thus, .RSNDR can be improved with respect to the case of non-optical preamplifier. For the preamplifier gain of 20 dB and noise figure of 3 dB, an improvement of about

  17. Microwave Photonics

    OpenAIRE

    Seeds, A.J.; Liu, C. P.; T. Ismail; Fice, M. J.; Pozzi, F; Steed, R. J.; Rouvalis, E.; Renaud, C.C.

    2010-01-01

    Microwave photonics is the use of photonic techniques for the generation, transmission, processing and reception of signals having spectral components at microwave frequencies. This tutorial reviews the technologies used and gives applications examples.

  18. Distorted Fingerprint Verification System

    Directory of Open Access Journals (Sweden)

    Divya KARTHIKAESHWARAN

    2011-01-01

    Full Text Available Fingerprint verification is one of the most reliable personal identification methods. Fingerprint matching is affected by non-linear distortion introduced in fingerprint impression during the image acquisition process. This non-linear deformation changes both the position and orientation of minutiae. The proposed system operates in three stages: alignment based fingerprint matching, fuzzy clustering and classifier framework. First, an enhanced input fingerprint image has been aligned with the template fingerprint image and matching score is computed. To improve the performance of the system, a fuzzy clustering based on distance and density has been used to cluster the feature set obtained from the fingerprint matcher. Finally a classifier framework has been developed and found that cost sensitive classifier produces better results. The system has been evaluated on fingerprint database and the experimental result shows that system produces a verification rate of 96%. This system plays an important role in forensic and civilian applications.

  19. Can CMB spectral distortions test the Einstein equivalence principle?

    CERN Document Server

    Arai, Shun; Tashiro, Hiroyuki

    2016-01-01

    The Einstein Equivalence Principle (EEP) can be verified by the measurement of the spectral distortions of the Cosmic Microwave Background (CMB). The existence of energy-dependency in the cosmological redshift effect means the EEP violation. Introducing the energy-dependent Friedmann-Robertson-Walker metric motivated by rainbow gravity, we show that the energy-dependent redshift effect causes the CMB spectral distortions. Assuming the simple energy-dependent form of the metric, we evaluate the distortions. From the COBE/FIRAS bound, we find that the deviation degree from the EEP, which is comparable to the difference of the parameterized-post-Newtonian parameter "gamma" in energy, is less than 10^{-9} at the CMB energy scale. Our bound is the first constraint on the EEP at cosmological time scale.

  20. CMB spectral distortions and energy release in the early universe

    Science.gov (United States)

    Tashiro, Hiroyuki

    2014-06-01

    Measuring the spectral deviation of the cosmic microwave background (CMB) from the blackbody spectrum has become a focus of attention as a probe of the thermal history of the Universe. It has been more than 20 years since COBE/FIRAS's measurement, which showed excellent agreement between the CMB spectrum and a perfect blackbody spectrum. Significant developments in the technology since then have allowed us to improve the sensitivity of the absolute spectrum measurement by a factor of {˜ }10^4. Therefore, the physics related to the generation of CMB spectral distortions should now be investigated in greater detail. To probe the physics in the early universe and to open an observational window for new physics, various energy release mechanisms both in and beyond standard cosmology need to be studied. In this paper, we provide a review of the physics of CMB distortions and the energy release that creates CMB distortions in the early universe.

  1. Inlet flow distortion in turbomachinery

    Science.gov (United States)

    Seidel, B. S.; Matwey, M. D.; Adamczyk, J. J.

    1980-01-01

    A single stage axial compressor with distorted inflow is studied. The inflow distortion occurs far upstream and may be a distortion in stagnation temperature, stagnation pressure or both. The blade rows are modeled as semi-actuator disks. Losses, quasi-steady deviation angles, and reference incidence correlations are included in the analysis. Both subsonic and transonic relative Mach numbers are considered. A parameter study is made to determine the influence of such variables as Mach number and swirl angle on the attenuation of the distortion.

  2. Analysis Of Overlay Distortion Patterns

    Science.gov (United States)

    Armitage, John D.; Kirk, Joseph P.

    1988-01-01

    A comprehensive geometrical approach is presented for the least-squares analysis of overlay distortion patterns into useful, physically meaningful systematic distortion subpatterns and an essentially non-systematic residue. A scheme of generally useful distortion sub-patterns is presented in graphic and algorithmic form; some of these sub-patterns are additions to those already in widespread use. A graphic and geometric approach is emphasized rather than an algebraic or statistical approach, and an example illustrates the value in utilizing the pattern-detecting ability of the eye-brain system. The conditions are described under which different distortion sub-patterns may interact, possibly leading to misleading or erroneous conclusions about the types and amounts of different distortions present. Examples of typical interaction situations are given, and recommendations are made for analytic procedures to avoid misinterpretation. It is noted that the lower-order distortion patterns preserve straight-line linearity, but that higher-order distortion may result in straight lines becoming curved. The principle of least-squares analysis is outlined and a simple polynomial data-fitting example is used to illustrate the method. Algorithms are presented for least-squares distortion analysis of overlay patterns, and an APL2 program is given to show how this may easily be implemented on a digital computer. The appendix extends the treatment to cases where small-angle approximation is not permissible.

  3. Algebraic Lens Distortion Model Estimation

    Directory of Open Access Journals (Sweden)

    Luis Alvarez

    2010-07-01

    Full Text Available A very important property of the usual pinhole model for camera projection is that 3D lines in the scene are projected to 2D lines. Unfortunately, wide-angle lenses (specially low-cost lenses may introduce a strong barrel distortion, which makes the usual pinhole model fail. Lens distortion models try to correct such distortion. We propose an algebraic approach to the estimation of the lens distortion parameters based on the rectification of lines in the image. Using the proposed method, the lens distortion parameters are obtained by minimizing a 4 total-degree polynomial in several variables. We perform numerical experiments using calibration patterns and real scenes to show the performance of the proposed method.

  4. Microwave Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Makes ultra-high-resolution field measurements. The Microwave Microscope (MWM) has been used in support of several NRL experimental programs involving sea...

  5. Comparative Centrifugal Distortion Analysis in Rotational Spectra of Propanol and Isopropanol Molecules

    Science.gov (United States)

    Qajar, Ch. O.; Kazimova, S. B.

    2015-07-01

    We have compared the effect of centrifugal distortion on the rotational spectra of isopropanol and propanol molecules in the microwave frequency range. We identified 61 rotational transitions of the propanol molecule with rotational quantum numbers up to J = 36 inclusive. We show that in order to satisfactorily take into account centrifugal distortion in the isopropanol molecule, it is sufficient to use only the quartic and sextic terms, while in calculating the rotational transitions of the propanol molecule we need to include all the way up to dectic centrifugal distortion constants.

  6. Triangulation in Random Refractive Distortions.

    Science.gov (United States)

    Alterman, Marina; Schechner, Yoav Y; Swirski, Yohay

    2017-03-01

    Random refraction occurs in turbulence and through a wavy water-air interface. It creates distortion that changes in space, time and with viewpoint. Localizing objects in three dimensions (3D) despite this random distortion is important to some predators and also to submariners avoiding the salient use of periscopes. We take a multiview approach to this task. Refracted distortion statistics induce a probabilistic relation between any pixel location and a line of sight in space. Measurements of an object's random projection from multiple views and times lead to a likelihood function of the object's 3D location. The likelihood leads to estimates of the 3D location and its uncertainty. Furthermore, multiview images acquired simultaneously in a wide stereo baseline have uncorrelated distortions. This helps reduce the acquisition time needed for localization. The method is demonstrated in stereoscopic video sequences, both in a lab and a swimming pool.

  7. Microwave Measurements

    CERN Document Server

    Skinner, A D

    2007-01-01

    The IET has organised training courses on microwave measurements since 1983, at which experts have lectured on modern developments. Their lecture notes were first published in book form in 1985 and then again in 1989, and they have proved popular for many years with a readership beyond those who attended the courses. The purpose of this third edition of the lecture notes is to bring the latest techniques in microwave measurements to this wider audience. The book begins with a survey of the theory of current microwave circuits and continues with a description of the techniques for the measureme

  8. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  9. Analysis of Intermodulation Interferences of GSM System on GSM - R System%GSM系统对GSM-R系统的互调干扰分析

    Institute of Scientific and Technical Information of China (English)

    邵翔

    2012-01-01

    Research purposes: Though the analysis of the frequencies and the possible second - order and third - order intermodulation interferences of the public GSM system and GSM - R system, the computer simulation is made to find out the interferences combinations for putting forward the advices on the frequency planning of the public GSM system along the railway.Research conclusions: (1) The possibility of the intermodulation interferences of the public GSM system on the GSM -R system is high. (2) The frequency planning of public GSM system alone railway shall be planned according to the used frequency of GSM - R system, so that the GSM - R system will not interfered by GSM system and safety of railway operation can be ensured. (3) When the business enterprise adjusts and optimizes the GSM - R network being along the railway, it is necessary to know the frequency points for GSM -R for optimizing to avoid the interference on the GSM -R system.%研究目的:通过分析公网GSM系统和铁路GSM -R系统的频点及可能产生的二阶及三阶互调干扰,用计算机仿真找到可能对铁路GSM-R频率产生干扰的频点组合,给铁路沿线公网GSM系统的频率规划提出建议.研究结论:(1)铁路沿线的公网GSM系统对铁路GSM -R系统产生互调干扰的概率很高;(2)在铁路沿线的公网GSM系统需根据GSM -R系统所使用的频率进行频率规划,以避免对GSM -R系统造成干扰,影响铁路安全运行;(3)运营商在对铁路沿线已建成的GSM网络进行频点调整优化时,需要了解铁路GSM -R使用的频点,再进行优化,避免对GSM -R系统造成干扰.

  10. CMB all-scale blackbody distortions induced by linearizing temperature

    Science.gov (United States)

    Notari, Alessio; Quartin, Miguel

    2016-08-01

    Cosmic microwave background (CMB) experiments, such as WMAP and Planck, measure intensity anisotropies and build maps using a linearized formula for relating them to the temperature blackbody fluctuations. However, this procedure also generates a signal in the maps in the form of y -type distortions which is degenerate with the thermal Sunyaev Zel'dovich (tSZ) effect. These are small effects that arise at second order in the temperature fluctuations not from primordial physics but from such a limitation of the map-making procedure. They constitute a contaminant for measurements of our peculiar velocity, the tSZ and primordial y -distortions. They can nevertheless be well modeled and accounted for. We show that the distortions arise from a leakage of the CMB dipole into the y -channel which couples to all multipoles, mostly affecting the range ℓ≲400 . This should be visible in Planck's y -maps with an estimated signal-to-noise ratio of about 12. We note however that such frequency-dependent terms carry no new information on the nature of the CMB dipole. This implies that the real significance of Planck's Doppler coupling measurements is actually lower than reported by the collaboration. Finally, we quantify the level of contamination in tSZ and primordial y -type distortions and show that it is above the sensitivity of proposed next-generation CMB experiments.

  11. Effects Of Field Distortions In Ih-apf Linac

    CERN Document Server

    Kapin, Valery; Yamada, S

    2004-01-01

    The project on developing compact medical accelera-tors for the tumor therapy using carbon ions has been started at the National Institute of Radiological Sciences (NIRS). Alternating-phase-focused (APF) linac using an interdigital H-mode (IH) cavity has been proposed for the injector linac. The IH-cavity is doubly ridged circular resonator loaded by the drift-tubes mounted on ridges with supporting stems. The effects of intrinsic and random field distortions in a practical design of the 4-MeV/u 200 MHz IH-APF linac are considered. The intrinsic field distortions in IH-cavity are caused by the asymmetry of the gap field due to presence of the drift-tube supporting stems and pair of ridges. The random field distortions are caused by drift-tube misalignments and non-regular deviations of the voltage distribution from programmed law. The RF fields in IH-cavity have been calculated using Microwave Studio (MWS) code. The effects of field distortions on beam dynamics have been simulated numerically.

  12. Microwave generator

    Science.gov (United States)

    Kwan, T.J.T.; Snell, C.M.

    1987-03-31

    A microwave generator is provided for generating microwaves substantially from virtual cathode oscillation. Electrons are emitted from a cathode and accelerated to an anode which is spaced apart from the cathode. The anode has an annular slit there through effective to form the virtual cathode. The anode is at least one range thickness relative to electrons reflecting from the virtual cathode. A magnet is provided to produce an optimum magnetic field having the field strength effective to form an annular beam from the emitted electrons in substantial alignment with the annular anode slit. The magnetic field, however, does permit the reflected electrons to axially diverge from the annular beam. The reflected electrons are absorbed by the anode in returning to the real cathode, such that substantially no reflexing electrons occur. The resulting microwaves are produced with a single dominant mode and are substantially monochromatic relative to conventional virtual cathode microwave generators. 6 figs.

  13. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2013-01-01

    Microwave photonics continues to see rapid growth. The integration of optical fiber and wireless networks has become a commercial reality and is becoming increasingly pervasive. Such hybrid technology will lead to many innovative applications, including backhaul solutions for mobile networks and ultrabroadband wireless networks that can provide users with very high bandwidth services. Microwave Photonics, Second Edition systematically introduces important technologies and applications in this emerging field. It also reviews recent advances in micro- and millimeter-wavelength and terahertz-freq

  14. An Improved Distortion Operator for Insurance Risks

    Institute of Scientific and Technical Information of China (English)

    GAO Jian-wei; QIU Wan-hua

    2002-01-01

    This paper reviews the distortion function approach developed in the actuarial literature for insurance risks. The main aim of this paper is to derive an extensive distortion operator, and to propose a new premium principle based on this extensive distortion operator. Furthermore, the non-robustness of general distortion operator is also discussed. Examples are provided using Bernoulli, Pareto, Lognormal and Gamma distribution assumptions.

  15. Study of passive intermodulation interference on Mobile communications antennas%移动通信天线的无源互调干扰研究

    Institute of Scientific and Technical Information of China (English)

    蒋江湖; 吴少周; 张世全

    2011-01-01

    This paper discusses passive intermodulation interference in mobile communication antennas.It introduces the passive nonlinear and its causes in antenna system.At the same time, this paper studies the measurements of mobile communication, provides the typical device measured antenna PIM, and tests the practicality of the measuring devices along with examples, Finally, this paper puts forward the ways of reducing PIM products in mobile communications antenna.%对移动通信天线的无源互调干扰问题进行了探讨与分析.介绍了天线系统中的无源非线性及其产生原因,对移动通信天线无源互调的测量进行了一定的探讨,给出了天线PIM测量的典型装置;结合测量实例检验了测量装置的实用性;最后提出了移动通信天线中PIM产物的减小措施.

  16. Volterra Series Based Distortion Effect

    DEFF Research Database (Denmark)

    Agerkvist, Finn T.

    2010-01-01

    A large part of the characteristic sound of the electric guitar comes from nonlinearities in the signal path. Such nonlinearities may come from the input- or output-stage of the amplier, which is often equipped with vacuum tubes or a dedicated distortion pedal. In this paper the Volterra series e...

  17. TPC track distortions IV: post tenebras lux

    CERN Document Server

    Ammosov, V; Boyko, I; Chelkov, G; Dedovitch, D; Dydak, F; Elagin, A; Gostkin, M; Guskov, A; Koreshev, V; Krumshtein, Z; Nefedov, Y; Nikolaev, K; Wotschack, J; Zhemchugov, A

    2007-01-01

    We present a comprehensive discussion and summary of static and dynamic track distortions in the HARP TPC in terms of physical origin, mathematical modelling and correction algorithms. `Static' distortions are constant with time, while `dynamic' distortions are distortions that occur only during the 400 ms long accelerator spill. The measurement of dynamic distortions, their mathematical modelling and the correction algorithms build on our understanding of static distortions. In the course of corroborating the validity of our static distortion corrections, their reliability and precision was further improved. Dynamic TPC distortions originate dominantly from the `stalactite' effect: a column of positive-ion charge starts growing at the begin of the accelerator spill, and continues growing with nearly constant velocity out from the sense-wire plane into the active TPC volume. However, the `stalactite' effect is not able to describe the distortions that are present already at the start of the spill and which ha...

  18. Microwave spectrum of 1-bromobutane

    Science.gov (United States)

    Kim, Jihyun; Jang, Heesu; Ka, Soohyun; Obenchain, Daniel A.; Peebles, Rebecca A.; Peebles, Sean A.; Oh, Jung Jin

    2016-10-01

    The rotational spectrum of 1-bromobutane has been measured in the range of 8-18 GHz using a 480 MHz bandwidth chirped-pulse Fourier transform microwave (CP-FTMW) spectrometer. 1-bromobutane has five conformers; aa, ag, ga, gg, gg‧. Spectra for the 79Br isotopic species and 81Br isotopic species were observed and assigned for the three lowest energy conformers, aa, ga, and gg. Consequentially, the rotational constants, nuclear quadrupole coupling constants, and centrifugal distortion constants were determined and the dipole moment of the aa conformer with 79Br was measured. All the experimental data are in good agreement with the ab initio calculations.

  19. Observation of the nonlinear meissner effect in YBCO thin films: evidence for a D-wave order parameter in the bulk of the cuprate superconductors.

    Science.gov (United States)

    Oates, D E; Park, S-H; Koren, G

    2004-11-05

    We present experimental evidence for the observation of the nonlinear Meissner effect in high-quality epitaxial yttrium barium copper oxide thin films by measuring their intermodulation distortion at microwave frequencies versus temperature. Most of the films measured show a characteristic increase in nonlinearity at low temperatures as predicted by the nonlinear Meissner effect. We could measure the nonlinear Meissner effect because intermodulation distortion measurements are an extremely sensitive method that can detect changes in the penetration depth of the order of 1 part in 10(5).

  20. Mobile Watermarking against Geometrical Distortions

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2015-08-01

    Full Text Available Mobile watermarking robust to geometrical distortions is still a great challenge. In mobile watermarking, efficient computation is necessary because mobile devices have very limited resources due to power consumption. In this paper, we propose a low-complexity geometrically resilient watermarking approach based on the optimal tradeoff circular harmonic function (OTCHF correlation filter and the minimum average correlation energy Mellin radial harmonic (MACE-MRH correlation filter. By the rotation, translation and scale tolerance properties of the two kinds of filter, the proposed watermark detector can be robust to geometrical attacks. The embedded watermark is weighted by a perceptual mask which matches very well with the properties of the human visual system. Before correlation, a whitening process is utilized to improve watermark detection reliability. Experimental results demonstrate that the proposed watermarking approach is computationally efficient and robust to geometrical distortions.

  1. Another look to distortions of the CMB spectrum

    CERN Document Server

    De Zotti, G; Castex, G; Lapi, A; Bonato, M

    2015-01-01

    We review aspects of cosmic microwave background spectral distortions which do not appear to have been fully explored in the literature. In particular, implications of recent evidences of heating of the intergalactic medium (IGM) by feedback from active galactic nuclei are investigated. Taking also into account the IGM heating associated to structure formation, we argue that values of the y parameter of several times 10^(-6), i.e. a factor of a few below the COBE/FIRAS upper limit, are to be expected. The Compton scattering by the re-ionized plasma also re-processes primordial Bose Einstein-type distortions, reshaping them; hence no pure Bose-Einstein-like distortions are to be expected. An assessment of Galactic and extragalactic foregrounds, taking into account the latest results from the Planck satellite as well as the contributions from the strong CII and CO lines from star-forming galaxies demonstrates that the foreground subtraction accurate enough to fully exploit the PIXIE sensitivity will be extremel...

  2. CMB all-scale blackbody distortions induced by linearizing temperature

    CERN Document Server

    Notari, Alessio

    2016-01-01

    Cosmic Microwave Background (CMB) experiments, such as WMAP and Planck, measure intensity anisotropies and build maps using a \\emph{linearized} formula for relating them to the temperature blackbody fluctuations. However such a procedure also generates a signal in the maps in the form of y-type distortions, and thus degenerate with the thermal SZ (tSZ) effect. These are small effects that arise at second-order in the temperature fluctuations not from primordial physics but from such a limitation of the map-making procedure. They constitute a contaminant for measurements of: our peculiar velocity, the tSZ and of primordial y-distortions, but they can nevertheless be well-modelled and accounted for. We show that the largest distortions arises at high ell from a leakage of the CMB dipole into the y-channel which couples to all multipoles, but mostly affects the range ell <~ 400. This should be visible in Planck's y-maps with an estimated signal-to-noise ratio of about 9. We note however that such frequency-de...

  3. Microwave photonics processing controlling the speed of light in semiconductor waveguides

    DEFF Research Database (Denmark)

    Xue, Weiqi; Chen, Yaohui; Sales, Salvador;

    2009-01-01

    We review the theory of slow and fast light effect in semiconductor waveguides and potential applications of these effects in microwave photonic systems as RF phase shifters. Recent applications as microwave photonic filters is presented. Also, in the presentation more applications like...... optoelectronic oscillators and arbitrary waveform generators will be described. Some work related to the noise and distortion will also be discussed...

  4. Speech distortion measure based on auditory properties

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo; HU Xiulin; ZHANG Yunyu; ZHU Yaoting

    2000-01-01

    The Perceptual Spectrum Distortion (PSD), based on auditory properties of human being, is presented to measure speech distortion. The PSD measure calculates the speech distortion distance by simulating the auditory properties of human being and converting short-time speech power spectrum to auditory perceptual spectrum. Preliminary simulative experiments in comparison with the Itakura measure have been done. The results show that the PSD measure is a perferable speech distortion measure and more consistent with subjective assessment of speech quality.

  5. SITMILARITY LAW FOR HYDRAULIC DISTORTED MODEL

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Newton's general similarity criterion was applied to the distorted model. The results for the similarities of gravity force, drag force and pressure force are identical with those derived from relevant differential equations of fluid flow. And the selected limits of the distorted ratio were studied and the simulation of roughness coefficient of distorted model was conducted by means of hydraulic test.

  6. Spectral distortion of the CMB by the cumulative CO emission from galaxies throughout cosmic history

    Science.gov (United States)

    Mashian, Natalie; Loeb, Abraham; Sternberg, Amiel

    2016-05-01

    We show that the cumulative CO emission from galaxies throughout cosmic history distorts the spectrum of the cosmic microwave background at a level that is well above the detection limit of future instruments, such as the Primordial Inflation Explorer. The modelled CO signal has a prominent bump in the frequency interval 100-200 GHz, with a characteristic peak intensity of ˜2 × 10-23 W m-2 Hz-1 sr-1. Most of the CO foreground originates from modest redshifts, z ˜ 2-5, and needs to be efficiently removed for more subtle distortions from the earlier Universe to be detected.

  7. Science with CMB spectral distortions

    CERN Document Server

    Chluba, Jens

    2014-01-01

    The measurements of COBE/FIRAS have shown that the CMB spectrum is extremely close to a perfect blackbody. There are, however, a number of processes in the early Universe that should create spectral distortions at a level which is within reach of present day technology. In this talk, I will give a brief overview of recent theoretical and experimental developments, explaining why future measurements of the CMB spectrum will open up an unexplored window to early-universe and particle physics with possible non-standard surprises but also several guaranteed signals awaiting us.

  8. Harmonic Distortion in CMOS Current Mirrors

    DEFF Research Database (Denmark)

    Bruun, Erik

    1998-01-01

    One of the origins of harmonic distortion in CMOS current mirrors is the inevitable mismatch between the MOS transistors involved. In this paper we examine both single current mirrors and complementary class AB current mirrors and develop an analytical model for the mismatch induced harmonic...... distortion. This analytical model is verified through simulations and is used for a discussion of the impact of mismatch on harmonic distortion properties of CMOS current mirrors. It is found that distortion levels somewhat below 1% can be attained by carefully matching the mirror transistors but ultra low...... distortion is not achievable with CMOS current mirrors...

  9. Analysis of Brown camera distortion model

    Science.gov (United States)

    Nowakowski, Artur; Skarbek, Władysław

    2013-10-01

    Contemporary image acquisition devices introduce optical distortion into image. It results in pixel displacement and therefore needs to be compensated for many computer vision applications. The distortion is usually modeled by the Brown distortion model, which parameters can be included in camera calibration task. In this paper we describe original model, its dependencies and analyze orthogonality with regard to radius for its decentering distortion component. We also report experiments with camera calibration algorithm included in OpenCV library, especially a stability of distortion parameters estimation is evaluated.

  10. Multiple scattering expansion with distortion

    Science.gov (United States)

    Tandy, P. C.; Thaler, R. M.

    1980-12-01

    A multiple scattering description of elastic scattering is formulated in terms of impulsive scatterings from single target nucleons and pairs of target nucleons. In this description, distortion effects on the projectile from the residual medium are also described by multiple scattering in terms of the same single and pair amplitudes. At the level of single scattering, this procedure yields the first order optical potential result of Kerman, McManus, and Thaler. When scattering from both single nucleons and pairs of nucleons is included, the method leads to a one-body integral equation which requires the physical projectile-nucleon and projectile-pair transition amplitudes as input. This input is similar, but not exactly equivalent to that required by the spectator expansion for the optical potential truncated at second order. A principal advantage of the present formulation is that there need be no explicit dependence upon the projection operator Q which projects off the target ground state. This feature introduces a scaling which appears to be a direct extension of the first order Kerman, McManus, and Thaler type of scaling. We follow up suggestions arising in the foregoing to show that the exact optical potential to second order in the spectator expansion can also be cast into a form having no explicit dependence upon Q, and requiring physical projectile-nucleon and projectile-pair transition amplitudes as input. NUCLEAR REACTIONS Multiple scattering from single nucleons, pairs of nucleons in nucleus. Distortion from residual medium. Optical potential. spectator expansion.

  11. Biological motion distorts size perception

    Science.gov (United States)

    Veto, Peter; Einhäuser, Wolfgang; Troje, Nikolaus F.

    2017-02-01

    Visual illusions explore the limits of sensory processing and provide an ideal testbed to study perception. Size illusions - stimuli whose size is consistently misperceived - do not only result from sensory cues, but can also be induced by cognitive factors, such as social status. Here we investigate, whether the ecological relevance of biological motion can also distort perceived size. We asked observers to judge the size of point-light walkers (PLWs), configurations of dots whose movements induce the perception of human movement, and visually matched control stimuli (inverted PLWs). We find that upright PLWs are consistently judged as larger than inverted PLWs, while static point-light figures do not elicit the same effect. We also show the phenomenon using an indirect paradigm: observers judged the relative size of a disc that followed an inverted PLW larger than a disc following an upright PLW. We interpret this as a contrast effect: The upright PLW is perceived larger and thus the subsequent disc is judged smaller. Together, these results demonstrate that ecologically relevant biological-motion stimuli are perceived larger than visually matched control stimuli. Our findings present a novel case of illusory size perception, where ecological importance leads to a distorted perception of size.

  12. Biological motion distorts size perception

    Science.gov (United States)

    Veto, Peter; Einhäuser, Wolfgang; Troje, Nikolaus F.

    2017-01-01

    Visual illusions explore the limits of sensory processing and provide an ideal testbed to study perception. Size illusions – stimuli whose size is consistently misperceived – do not only result from sensory cues, but can also be induced by cognitive factors, such as social status. Here we investigate, whether the ecological relevance of biological motion can also distort perceived size. We asked observers to judge the size of point-light walkers (PLWs), configurations of dots whose movements induce the perception of human movement, and visually matched control stimuli (inverted PLWs). We find that upright PLWs are consistently judged as larger than inverted PLWs, while static point-light figures do not elicit the same effect. We also show the phenomenon using an indirect paradigm: observers judged the relative size of a disc that followed an inverted PLW larger than a disc following an upright PLW. We interpret this as a contrast effect: The upright PLW is perceived larger and thus the subsequent disc is judged smaller. Together, these results demonstrate that ecologically relevant biological-motion stimuli are perceived larger than visually matched control stimuli. Our findings present a novel case of illusory size perception, where ecological importance leads to a distorted perception of size. PMID:28205639

  13. Microwave power engineering applications

    CERN Document Server

    Okress, Ernest C

    2013-01-01

    Microwave Power Engineering, Volume 2: Applications introduces the electronics technology of microwave power and its applications. This technology emphasizes microwave electronics for direct power utilization and transmission purposes. This volume presents the accomplishments with respect to components, systems, and applications and their prevailing limitations in the light of knowledge of the microwave power technology. The applications discussed include the microwave heating and other processes of materials, which utilize the magnetron predominantly. Other applications include microwave ioni

  14. Advances in microwaves 8

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 8 covers the developments in the study of microwaves. The book discusses the circuit forms for microwave integrated circuits; the analysis of microstrip transmission lines; and the use of lumped elements in microwave integrated circuits. The text also describes the microwave properties of ferrimagnetic materials, as well as their interaction with electromagnetic waves propagating in bounded waveguiding structures. The integration techniques useful at high frequencies; material technology for microwave integrated circuits; specific requirements on technology for d

  15. Lens distortion calibration by explicit straight-line to distorted-line geometric mapping

    Science.gov (United States)

    Wu, Xianghai; Kofman, Jonathan

    2004-10-01

    Medium and wide-angle off-shelf cameras are often used in computer-vision applications despite their large lens distortion. Algorithms to correct for radial and tangential distortion are available; however, they often use non-linear optimization search methods that rely on carefully chosen starting points. This paper presents a method to correct for both radial symmetric lens distortion and decentering lens distortion using an iterative geometric approach to find the distortion center, and a closed-form solution for all other distortion parameters. The method is based on deriving an equivalent radial symmetric distortion model that accounts for both radial and tangential distortion. The technique uses the simple geometric relationship between a straight line and its distorted counterpart under this distortion model. The distortion calibration involves firstly determining the axis of symmetry of several distorted lines. The intersection of these axes is then computed and considered as the point of best radial symmetry (PBRS). The inclinations of the axes of symmetry of the distorted lines are then used in a closed-form solution to determine the distortion coefficients. One advantage of this approach is that higher-order coefficients can be included as needed, with their computation still achieved in closed form. The simplicity of the lens distortion calibration technique has been demonstrated in a simulation using synthetic images.

  16. The cosmic microwave background - A probe of particle physics

    Science.gov (United States)

    Silk, Joseph

    1990-01-01

    The current status of spectral distortions and angular anisotropies in the cosmic microwave background is reviewed, with emphasis on the role played by weakly interacting particle dark matter. Theoretical predictions and recent observational results are described, and prospects for future progress are summarized.

  17. Dynamic Dazzle Distorts Speed Perception.

    Directory of Open Access Journals (Sweden)

    Joanna R Hall

    Full Text Available Static high contrast ('dazzle' patterns, such as zigzags, have been shown to reduce the perceived speed of an object. It has not escaped our notice that this effect has possible military applications and here we report a series of experiments on humans, designed to establish whether dynamic dazzle patterns can cause distortions of perceived speed sufficient to provide effective defence in the field, and the extent to which these effects are robust to a battery of manipulations. Dynamic stripe patterns moving in the same direction as the target are found to increase the perceived speed of that target, whilst dynamic stripes moving in the opposite direction to the target reduce the perceived speed. We establish the optimum position for such dazzle patches; confirm that reduced contrast and the addition of colour do not affect the performance of the dynamic dazzle, and finally, using the CO2 challenge, show that the effect is robust to stressful conditions.

  18. Nonlinear Phase Distortion in a Ti:Sapphire Optical Amplifier for Optical Stochastic Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Andorf, Matthew [NICADD, DeKalb; Lebedev, Valeri [Fermilab; Piot, Philippe [NICADD, DeKalb; Ruan, Jinhao [Fermilab

    2016-06-01

    Optical Stochastic Cooling (OSC) has been considered for future high-luminosity colliders as it offers much faster cooling time in comparison to the micro-wave stochastic cooling. The OSC technique relies on collecting and amplifying a broadband optical signal from a pickup undulator and feeding the amplified signal back to the beam. It creates a corrective kick in a kicker undulator. Owing to its superb gain qualities and broadband amplification features, Titanium:Sapphire medium has been considered as a gain medium for the optical amplifier (OA) needed in the OSC*. A limiting factor for any OA used in OSC is the possibility of nonlinear phase distortions. In this paper we experimentally measure phase distortions by inserting a single-pass OA into one leg of a Mach-Zehnder interferometer. The measurement results are used to estimate the reduction of the corrective kick a particle would receive due to these phase distortions in the kicker undulator.

  19. Constraints on Gravitino Decay and the Scale of Inflation using CMB spectral distortions

    CERN Document Server

    Dimastrogiovannia, Emanuela; Chlubac, Jens

    2016-01-01

    If local supersymmetry is the correct extension of the standard model of particle physics, then following Inflation the early universe would have been populated by gravitinos produced from scatterings in the hot plasma during reheating. Their abundance is directly related to the magnitude of the reheating temperature. The gravitino lifetime is fixed as a function of its mass, and for gravitinos with lifetimes longer than the age of the universe at redshift $z\\simeq 2\\times 10^{6}$ (or roughly $6\\times 10^6{\\rm s}$), decay products can produce spectral distortion of the cosmic microwave background. Currently available COBE/FIRAS limits on spectral distortion can, in certain cases, already be competitive with respect to cosmological constraints from primordial nucleosynthesis for some gravitino decay scenarios. We show how the sensitivity limits on $\\mu$ and \\textsl{y} distortions that can be reached with current technology would improve constraints and possibly rule out a significant portion of the parameter s...

  20. Microscopic distorted wave theory of inelastic scattering

    Science.gov (United States)

    Picklesimer, A.; Tandy, P. C.; Thaler, R. M.

    1982-03-01

    An exact microscopic distorted wave theory of inelastic scattering is formulated which contains the physical picture usually associated with distorted wave approximations without the usual redundancy. This formulation encompasses the inelastic scattering of two fragments, elementary or composite (both with or without the full complexity of interfragment Pauli symmetries). The fact that these considerations need not be based upon elementary potential interactions is an indication of the generality of the approach and supports its applicability to inelastic meson scattering. The theory also maintains a description of inelastic scattering which is a natural extension of the description of elastic scattering and it provides a general basis for obtaining truncation models with an explicit distorted wave structure. The distorted wave impulse approximation is presented as an example of a particular truncation/approximation encompassed by this theory and the nature of the distorted waves is explicated. NUCLEAR REACTIONS Distorted wave theory, inelastic scattering, multiple scattering, spectator expansion, Pauli exclusion principle, composite particles, unitarity structure.

  1. Cognitive Distortions, Humor Styles, and Depression

    Directory of Open Access Journals (Sweden)

    Katerina Rnic

    2016-08-01

    Full Text Available Cognitive distortions are negative biases in thinking that are theorized to represent vulnerability factors for depression and dysphoria. Despite the emphasis placed on cognitive distortions in the context of cognitive behavioural theory and practice, a paucity of research has examined the mechanisms through which they impact depressive symptomatology. Both adaptive and maladaptive styles of humor represent coping strategies that may mediate the relation between cognitive distortions and depressive symptoms. The current study examined the correlations between the frequency and impact of cognitive distortions across both social and achievement-related contexts and types of humor. Cognitive distortions were associated with reduced use of adaptive Affiliative and Self-Enhancing humor styles and increased use of maladaptive Aggressive and Self-Defeating humor. Reduced use of Self-Enhancing humor mediated the relationship between most types of cognitive distortions and depressed mood, indicating that distorted negative thinking may interfere with an individual’s ability to adopt a humorous and cheerful outlook on life (i.e., use Self-Enhancing humor as a way of regulating emotions and coping with stress, thereby resulting in elevated depressive symptoms. Similarly, Self-Defeating humor mediated the association of the social impact of cognitive distortions with depression, such that this humor style may be used as a coping strategy for dealing with distorted thinking that ultimately backfires and results in increased dysphoria.

  2. Cognitive Distortions, Humor Styles, and Depression

    Science.gov (United States)

    Rnic, Katerina; Dozois, David J. A.; Martin, Rod A.

    2016-01-01

    Cognitive distortions are negative biases in thinking that are theorized to represent vulnerability factors for depression and dysphoria. Despite the emphasis placed on cognitive distortions in the context of cognitive behavioural theory and practice, a paucity of research has examined the mechanisms through which they impact depressive symptomatology. Both adaptive and maladaptive styles of humor represent coping strategies that may mediate the relation between cognitive distortions and depressive symptoms. The current study examined the correlations between the frequency and impact of cognitive distortions across both social and achievement-related contexts and types of humor. Cognitive distortions were associated with reduced use of adaptive Affiliative and Self-Enhancing humor styles and increased use of maladaptive Aggressive and Self-Defeating humor. Reduced use of Self-Enhancing humor mediated the relationship between most types of cognitive distortions and depressed mood, indicating that distorted negative thinking may interfere with an individual’s ability to adopt a humorous and cheerful outlook on life (i.e., use Self-Enhancing humor) as a way of regulating emotions and coping with stress, thereby resulting in elevated depressive symptoms. Similarly, Self-Defeating humor mediated the association of the social impact of cognitive distortions with depression, such that this humor style may be used as a coping strategy for dealing with distorted thinking that ultimately backfires and results in increased dysphoria. PMID:27547253

  3. Practical microwave electron devices

    CERN Document Server

    Meurant, Gerard

    2013-01-01

    Practical Microwave Electron Devices provides an understanding of microwave electron devices and their applications. All areas of microwave electron devices are covered. These include microwave solid-state devices, including popular microwave transistors and both passive and active diodes; quantum electron devices; thermionic devices (including relativistic thermionic devices); and ferrimagnetic electron devices. The design of each of these devices is discussed as well as their applications, including oscillation, amplification, switching, modulation, demodulation, and parametric interactions.

  4. The Quadratic Gaussian Rate-Distortion Function for Source Uncorrelated Distortions

    CERN Document Server

    Derpich, Milan S; Goodwin, Graham C

    2008-01-01

    We characterize the rate-distortion function for zero-mean stationary Gaussian sources under the MSE fidelity criterion and subject to the additional constraint that the distortion is uncorrelated to the input. The solution is given by two equations coupled through a single scalar parameter. This has a structure similar to the well known water-filling solution obtained without the uncorrelated distortion restriction. Our results fully characterize the unique statistics of the optimal distortion. We also show that, for all positive distortions, the minimum achievable rate subject to the uncorrelation constraint is strictly larger than that given by the un-constrained rate-distortion function. This gap increases with the distortion and tends to infinity and zero, respectively, as the distortion tends to zero and infinity.

  5. Traversable wormholes in distorted gravity

    Science.gov (United States)

    Garattini, Remo

    2015-07-01

    In this paper, we consider the effects of distorted gravity on the traversability of the wormholes. In particular, we consider configurations which are sustained by their own gravitational quantum fluctuations. The Ultraviolet divergences appearing to one loop are taken under control with the help of a Noncommutative geometry representation and gravity's rainbow. In this context, it will be shown that for every framework, the self-sustained equation will produce a Wheeler wormhole, namely a wormhole of Planckian size. This means that, from the point of view of traversability, the wormhole will be traversable in principle, but not in practice. For this purpose, in the context of gravity's rainbow we have considered different proposals of rainbow's functions to see if the smallness of the wormhole is dependent on the chosen form of the rainbow's function. Unfortunately, we discover that this is not the case and we suggest that the self-sustained equation can be improved to see if the wormhole radius can be enlarged or not. Some consequences on topology change are discussed.

  6. Traversable Wormholes in Distorted Gravity

    CERN Document Server

    Garattini, Remo

    2015-01-01

    We consider the effects of Distorted Gravity on the traversability of the wormholes. In particular, we consider configurations which are sustained by their own gravitational quantum fluctuations. The Ultra-Violet divergences appearing to one loop are taken under control with the help of a Noncommutative geometry representation and Gravity's Rainbow. In this context, it will be shown that for every framework, the self-sustained equation will produce a Wheeler wormhole, namely a wormhole of Planckian size. This means that, from the point of view of traversability, the wormhole will be traversable in principle, but not in practice. To this purpose, in the context of Gravity's Rainbow we have considered different proposals of rainbow's functions to see if the smallness of the wormhole is dependent on the chosen form of the rainbow's function. Unfortunately, we discover that this is not the case and we suggest that the self-sustained equation can be improved to see if the wormhole radius can be enlarged or not. So...

  7. Self-Compassion and Interpersonal Cognitive Distortions

    Science.gov (United States)

    Akin, Ahmet

    2010-01-01

    The purpose of this study is to examine the relationships between self-compassion and interpersonal cognitive distortions. Participants were 338 university students. In this study, the Self-compassion Scale and the Interpersonal Cognitive Distortions Scale were used. The relationships between self-compassion and interpersonal cognitive distortions…

  8. Tests of the CMB temperature-redshift relation, CMB spectral distortions and why adiabatic photon production is hard

    CERN Document Server

    Chluba, Jens

    2014-01-01

    In the expanding Universe, the average temperature of the cosmic microwave background (CMB) is expected to depend like TCMB (1+z) on redshift z. Adiabatic photon production (or destruction) or deviations from isotropy and homogeneity could modify this scaling and several observational tests have been carried out in response. Here, we explain why `adiabatic' conditions are extremely difficult to establish in the redshift range targeted by these tests. Thus, instead of leading to a simple rescaling of the CMB temperature, a spectral distortion should be produced, which can be constrained using COBE/FIRAS. For scenarios with late photon production, tests of the temperature-redshift relation (TRR) should therefore be reinterpreted as weak spectral distortion limits, directly probing the energy dependence of the photon production process. For inhomogeneous cosmologies, a y-type distortion is produced, but this type of distortion can be created in several ways. Here, we briefly discuss possible effects that may hel...

  9. Microscopic distorted wave theory of inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Picklesimer, A.; Tandy, P.C.; Thaler, R.M.

    1982-03-01

    An exact microscopic distorted wave theory of inelastic scattering is formulated which contains the physical picture usually associated with distorted wave approximations without the usual redundancy. This formulation encompasses the inelastic scattering of two fragments, elementary or composit (both with or without the full complexity of interfragment Pauli symmetries). The fact that these considerations need not be based upon elementary potential interactions is an indication of the generality of the approach and supports its applicability to inelastic meson scattering. This theory also maintains a description of inelastic scattering which is a natural extension of the description of elastic scattering and it provides a general basis for obtaining truncation models with an explicit distorted wave structure. This distorted wave impulse approximation is presented as an example of a particular truncation/approximation encompassed by this theory and the nature of the distorted waves is explicated.

  10. Hybrid distortion function for JPEG steganography

    Science.gov (United States)

    Wang, Zichi; Zhang, Xinpeng; Yin, Zhaoxia

    2016-09-01

    A hybrid distortion function for JPEG steganography exploiting block fluctuation and quantization steps is proposed. To resist multidomain steganalysis, both spatial domain and discrete cosine transformation (DCT) domain are involved in the proposed distortion function. In spatial domain, a distortion value is allotted for each 8×8 block according to block fluctuation. In DCT domain, quantization steps are employed to allot distortion values for DCT coefficients in a block. The two elements, block distortion and quantization steps, are combined together to measure the embedding risk. By employing the syndrome trellis coding to embed secret data, the embedding changes are constrained in complex regions, where modifications are hard to be detected. When compared to current state-of-the-art steganographic methods for JPEG images, the proposed method presents less detectable artifacts.

  11. TPC track distortions III: fiat lux

    CERN Document Server

    Boyko, I; Dydak, F; Elagin, A; Gostkin, M; Guskov, A; Koreshev, V; Nefedov, Y; Nikolaev, K; Veenhof, R; Wotschack, J; Zhemchugov, A

    2005-01-01

    We present a comprehensive overview and final summary of all four types of static track distortions seen in the HARP TPC, in terms of physical origins, mathematical modelling, and correction algorithms. 'Static'™ distortions are defined as not depending on the event time within the 400 ms long accelerator spill. Calculated static distortions are compared with measurements from cosmic-muon tracks. We characterize track distortions by the r phi residuals of cluster positions with respect to the transverse projection of a helical trajectory constrained by hits in the RPC overlap regions. This method provides a fixed TPC-external reference system (by contrast to the co-moving coordinate system associated with a fit) which solely permits to identify individually, and measure quantitatively, the static TPC track distortions arising from (i) the inhomogeneity of the solenoidal magnetic field, (ii) the inhomogeneity of the electric field from the high-voltage mismatch between the inner and outer TPC field cages, (...

  12. Scattering integral equations for distorted transition operators

    Energy Technology Data Exchange (ETDEWEB)

    Kowalski, K.L.; Siciliano, E.R.; Thaler, R.M.

    1978-11-01

    Methods for embedding phenomenological distorted-wave techniques for rearrangement and inelastic scattering within well-defined theories of multiparticle scattering are developed. The essential point of contact between the two approaches is in the definition and choice of distorting potential. It is shown that the concept of a channel coupling scheme allows a comparative freedom of choice for these potentials; if they are connected operators, such as optical potentials, then it is possible to obtain connected-kernel equations for the distorted transition operators. The latter are introduced in the course of exploiting the two-potential formula for the full transition operator and have the property that their matrix elements with respect to distorted waves are the physical scattering amplitudes. It is found that the distorted counterparts of the Kouri, Levin, and Tobocman and the Bencze-Redish integral equations maintain their connected-kernel and minimally coupled properties. These equations can be used to derive other integral equations with the same properties for the distorted-wave operators which consist of the product of the distorted transition operators and the wave operators corresponding to distorted waves. These simplifications are not realized for arbitrary channel coupling schemes. In order to deal with the general situation an alternative approach employing a subtraction technique which involves projections on the bound two-cluster channel states is introduced. When the distorting potentials are essentially the optical potentials in the entrance and exit channels a set of multichannel two-particle Lippmann-Schwinger integral equations for the two-cluster distorted-wave transition operators are obtained. Input into these two-particle integral equations involves the solution of a modified N-particle equation. Approximations to the latter are discussed in the particular cases of the Kouri, Levin, and Tobocman and Bencze-Redish channel coupling schemes.

  13. Effects of Field Distortions in IH-APF Linac for a Compact Medical Accelerator

    CERN Document Server

    Kapin, Valery; Yamada, Satoru

    2004-01-01

    The project on developing compact medical accelerators for the tumor therapy using carbon ions has been started at the National Institute of Radiological Sciences (NIRS). Alternating-phase-focused (APF) linac using an interdigital H-mode (IH) cavity has been proposed for the injector linac. The IH-cavity is a doubly ridged circular resonator loaded by the drift-tubes mounted on ridges with supporting stems. The effects of intrinsic and random field distortions in a practical design of the 4-Mev/u 200-MHz IH-APF linac are considered. The intrinsic field distortions in the IH-cavity are caused by an asymmetry of the gap fields due to presence of the stems and pair of ridges. The random field distortions are caused by drift-tube misalignments and non-regular deviations of the gap voltages from programmed values. The RF fields in the IH-cavity have been calculated using Microwave Studio (MWS) code. The effects of field distortions on beam dynamics have been simulated numerically. The intrinsic field distortions a...

  14. Model-Corrected Microwave Imaging through Periodic Wall Structures

    Directory of Open Access Journals (Sweden)

    Paul C. Chang

    2012-01-01

    Full Text Available A model-based imaging framework is applied to correct the target distortion seen in microwave imaging through a periodic wall structure. In addition to propagation delays caused by the wall, it is shown that the structural periodicity induces high-order space harmonics leading to other ghost artifacts in the through-wall image. To overcome these distortions, the periodic layer Green’s function is incorporated into the forward model. A linear back-projection solution and a nonlinear minimization solution are applied to solve the inverse problem. The model-based back-projection image corrects the distortion and has higher resolution compared with free space due to the inclusion of multipath propagation through the periodic wall, but considerable sidelobe clutter is present. The nonlinear solution not only corrects target distortion without clutter but also reduces the solution to a sparse form.

  15. Doppler-free intermodulated fluorescence spectroscopy of $^4He$ $2^3P-3^{1,3}D$ transitions at 588 nm with a one-watt compact laser system

    CERN Document Server

    Luo, Pei-Ling; Feng, Yan; Wang, Li-Bang; Shy, Jow-Tsong

    2015-01-01

    We have demonstrated Doppler-free intermodulated fluorescence spectroscopy of helium $2^3P-3^{1,3}D$ transitions in an rf discharged sealed-off cell using a compact laser system at 588 nm. An external cavity diode laser at 1176 nm was constructed to seed a Raman fiber amplifier. Laser power of more than one watt at 588 nm was produced by frequency doubling of the fiber amplifier output using a MgO:PPLN crystal. A doubling efficiency of 23 % was achieved. The power-dependent spectra of the $2^3P-3^3D$ transitions were investigated. Furthermore, the Doppler-free spectrum of the spin-forbidden $2^3P-3^1D$ transitions was observed for the first time. Our results are crucial towards precision test of QED atomic calculations, especially for improving the determination of the helium $3^1D-3^3D$ separation.

  16. Spectral distortions of the CMB dipole

    CERN Document Server

    Balashev, S A; Chluba, J; Ivanchik, A V; Varshalovich, D A

    2015-01-01

    We consider the distortions of the CMB dipole anisotropy related to the primordial recombination radiation (PRR) and primordial $y$- and $\\mu$-distortions. The signals arise due to our motion relative to the CMB restframe and appear as a frequency-dependent distortion of the CMB temperature dipole. To leading order, the expected relative distortion of CMB dipole does not depend on the particular observation directions and reaches the level of $10^{-6}$ for the PRR- and $\\mu$-distortions and $10^{-5}$ for the $y$-distortion in the frequency range 1 $-$ 700 GHz. The temperature differences arising from the dipole anisotropy of the relic CMB distortions depend on observation directions. For mutually opposite directions, collinear to the CMB dipole axis, the temperature differences because of the PRR- and $\\mu$-dipole anisotropy attain values $\\Delta T\\simeq 10\\,$nK in the considered range. The temperature difference arising from the $y$-dipole anisotropy may reach values up to $1\\,\\mu$K. The key features of the ...

  17. Distortional Modes of Thin-Walled Beams

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Andreassen, Michael Joachim

    2009-01-01

    The classic thin-walled beam theory for open and closed cross-sections can be generalized by including distortional displacement modes. The introduction of additional displacement modes leads to coupled differential equations, which seems to have prohibited the use of exact shape functions...... in the modelling of coupled torsion and distortion. However, if the distortional displacement modes are chosen as those which decouple the differential equations as in non proportionally damped modal dynamic analysis then it may be possible to use exact shape functions and perform analysis on a reduced problem...

  18. Testing for Distortions in Performance Measures

    DEFF Research Database (Denmark)

    Sloof, Randolph; Van Praag, Mirjam

    Distorted performance measures in compensation contracts elicit suboptimal behavioral responses that may even prove to be dysfunctional (gaming). This paper applies the empirical test developed by Courty and Marschke (2008) to detect whether the widely used class of Residual Income based...... performance measures —such as Economic Value Added (EVA)— is distorted, leading to unintended agent behavior. The paper uses a difference-in-differences approach to account for changes in economic circumstances and the self-selection of firms using EVA. Our findings indicate that EVA is a distorted...... performance measure that elicits the gaming response....

  19. Testing for Distortions in Performance Measures

    DEFF Research Database (Denmark)

    Sloof, Randolph; Van Praag, Mirjam

    2015-01-01

    used class of residual income-based performance measures-such as economic value added (EVA)-is distorted, leading to unintended agent behavior. The paper uses a difference-in-differences approach to account for changes in economic circumstances and the self-selection of firms using EVA. Our findings......Distorted performance measures in compensation contracts elicit suboptimal behavioral responses that may even prove to be dysfunctional (gaming). This paper applies the empirical test developed by Courty and Marschke (Review of Economics and Statistics, 90, 428-441) to detect whether the widely...... indicate that EVA is a distorted performance measure that elicits the gaming response....

  20. Lattice distortion in disordered antiferromagnetic XY models

    Institute of Scientific and Technical Information of China (English)

    Li Peng-Fei; Cao Hai-Jing

    2012-01-01

    The behavior of lattice distortion in spin 1/2 antiferromagnetic XY models with random magnetic modulation is investigated with the consideration of spin-phonon coupling in the adiabatic limit.It is found that lattice distortion relies on the strength of the random modulation.For strong or weak enough spin-phonon couplings,the average lattice distortion may decrease or increase as the random modulation is strengthened.This may be the result of competition between the random magnetic modulation and the spin-phonon coupling.

  1. Microwave Breast Imaging Techniques

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Rubæk, Tonny

    2010-01-01

    This paper outlines the applicability of microwave radiation for breast cancer detection. Microwave imaging systems are categorized based on their hardware architecture. The advantages and disadvantages of various imaging techniques are discussed. The fundamental tradeoffs are indicated between v...

  2. Microwave Breast Imaging Techniques

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Rubæk, Tonny

    2010-01-01

    This paper outlines the applicability of microwave radiation for breast cancer detection. Microwave imaging systems are categorized based on their hardware architecture. The advantages and disadvantages of various imaging techniques are discussed. The fundamental tradeoffs are indicated between...

  3. Properties of the distorted Kerr black hole

    CERN Document Server

    Abdolrahimi, Shohreh; Nedkova, Petya; Tzounis, Christos

    2015-01-01

    We investigate the properties of the ergoregion and the location of the curvature singularities for the Kerr black hole distorted by the gravitational field of external sources. The particular cases of quadrupole and octupole distortion are studied in detail. We also investigate the scalar curvature invariants of the horizon and compare their behaviour with the case of the isolated Kerr black hole. In a certain region of the parameter space the ergoregion consists of a compact region encompassing the horizon and a disconnected part extending to infinity. The curvature singularities in the domain of outer communication, when they exist, are always located on the boundary of the ergoregion. We present arguments that they do not lie on the compact ergosurface. For quadrupole distortion the compact ergoregion size is negatively correlated with the horizon angular momentum when the external sources are varied. For octupole distortion infinitely many ergoregion configurations can exist for a certain horizon angular...

  4. Perceived Coding Distortion Assessment for Streaming Video

    Directory of Open Access Journals (Sweden)

    Fuzheng Yang

    2010-04-01

    Full Text Available For applications involving video streaming, full decoding is usually not acceptable for quality assessment. To address the inherent challenges, an efficient method for coding distortion assessment is proposed in this paper. Building on empirical analysis, the proposed method employs a linear model to assess the coding distortion using the quantization scale. Furthermore, the characteristics of the human visual system are exploited by taking into account the spatial and temporal masking. To estimate the required spatial and temporal complexities in absence of sufficient information, a rate-distortion model is theoretically derived to formulate their relationship with the coding bit-rate. Extensive experimental results have demonstrated the effectiveness of the proposed method for quality assessment with respect to perceived coding distortion.

  5. Advances in microwaves 7

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 7 covers the developments in the study of microwaves. The book discusses the effect of surface roughness on the propagation of the TEM mode, as well as the voltage breakdown of microwave antennas. The text also describes the theory and design considerations of single slotted-waveguide linear arrays and the techniques and theories that led to the achievement of wide bandwidths and ultralow noise temperatures for communication applications. The book will prove invaluable to microwave engineers.

  6. Coulomb Distortion in the Inelastic Regime

    Energy Technology Data Exchange (ETDEWEB)

    Patricia Solvignon, Dave Gaskell, John Arrington

    2009-09-01

    The Coulomb distortion effects have been for a long time neglected in deep inelastic scattering for the good reason that the incident energies were very high. But for energies in the range of earlier data from SLAC or at JLab, the Coulomb distortion could have the potential consequence of affecting the A-dependence of the EMC effect and of the longitudinal to transverse virtual photon absorption cross section ratio $R(x,Q^2)$.

  7. Domestic Distortions and the Deindustrialization Hypothesis

    OpenAIRE

    Paul Krugman

    1996-01-01

    It is widely believed that U.S. trade deficits have displaced workers from highly paid manufacturing jobs into less well-paid service employment, contributing to declining incomes for the nation as a whole. Although proponents of this view do not usually think of it this way, this analysis falls squarely into the `domestic distortions' framework pioneered by Jagdish Bhagwati. This paper models the deindustrialization hypothesis explicitly as a domestic distortions issue, and shows that while ...

  8. Welding distortion of aluminium structural members

    Energy Technology Data Exchange (ETDEWEB)

    Goglio, L. [Politecnico di Torino (Italy). Dept. of Mech.; Gugliotta, A. [Politecnico di Torino (Italy). Dept. of Mech.; Pasquino, D. [Politecnico di Torino (Italy). Dept. of Mech.

    1996-12-31

    The paper deals with the angular distortion induced in aluminium tubular beams during welding to prepare T junctions. The research, based on experimental measurements, makes use of statistical methods to identify the parameters (beam section, weld length, welding direction, etc.) that influence the angular change. The results are discussed also considering a model known from the literature. It is found that the distortion is generally low and can be minimized by a proper welding process. (orig.)

  9. Advanced Machining Toolpath for Low Distortion

    Science.gov (United States)

    2017-02-28

    modeling software packages. Efforts in Production Module consisted of setting up an analysis of cutting forces across the fatigue coupon toolpath and...in the distortion modeling software focused on simulating final part distortion due to the initial bulk stress in the aluminum stock material. TWS...process. In each plot, the red force trace is the original toolpath and the green force trace is the optimized toolpath. In both toolpaths, cutting

  10. Straight line feature based image distortion correction

    Institute of Scientific and Technical Information of China (English)

    Zhang Haofeng; Zhao Chunxia; Lu Jianfeng; Tang Zhenmin; Yang Jingyu

    2008-01-01

    An image distortion correction method is proposed, which uses the straight line features. Many parallel lines of different direction from different images were extracted, and then were used to optimize the distortion parameters by nonlinear least square. The thought of step by step was added when the optimization method working. 3D world coordi-nation is not need to know, and the method is easy to implement. The experiment result shows its high accuracy.

  11. Microwave Radiometer (MWR) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Morris, VR

    2006-08-01

    The Microwave Radiometer (MWR) provides time-series measurements of column-integrated amounts of water vapor and liquid water. The instrument itself is essentially a sensitive microwave receiver. That is, it is tuned to measure the microwave emissions of the vapor and liquid water molecules in the atmosphere at specific frequencies.

  12. Nonlinearities in Microwave Superconductivity

    OpenAIRE

    Ledenyov, Dimitri O.; Ledenyov, Viktor O.

    2012-01-01

    The research is focused on the modeling of nonlinear properties of High Temperature Superconducting (HTS) thin films, using Bardeen, Cooper, Schrieffer and Lumped Element Circuit theories, with purpose to enhance microwave power handling capabilities of microwave filters and optimize design of microwave circuits in micro- and nano- electronics.

  13. An Air Jet Distortion Generation System

    Directory of Open Access Journals (Sweden)

    M. Sivapragasam

    2014-01-01

    Full Text Available An air jet distortion generation system is developed to simulate the distorted flow field ahead of gas turbine engines in ground test facility. The flow field of a system of four jets arranged circumferentially and issuing into a confined counterflow was studied experimentally and numerically. The total pressure distortion parameters were evaluated at the Aerodynamic Interface Plane (AIP for several values of mass flow ratios. Since the total pressure loss distribution at the AIP is characteristically “V” shaped, the number of jets was increased to obtain total pressure distributions as required for gas turbine engine testing. With this understanding, a methodology has been developed to generate a target total pressure distortion pattern at the AIP. Turbulent flow computations are used to iteratively progress towards the target distribution. This methodology was demonstrated for a distortion flow pattern typical of use in gas turbine engine testing using twenty jets, which is a smaller number than reported in the literature. The procedure converges with a root-mean-square error of 3.836% and is able to reproduce the target pattern and other distortion parameters.

  14. Low distortion laser welding of cylindrical components

    Science.gov (United States)

    Kittel, Sonja

    2011-02-01

    Automotive components are for the most part cylindrical and thus the weld seams are of radial shape. Radial weld seams are usually produced by starting at a point on the component's surface rotating the component resulting in an overlap zone at the start/end of the weld. In this research, it is shown that the component's distortion strongly depends on the overlap of weld start and end. A correlation between overlap zone and distortion is verified by an experimental study. In order to reduce distortion generated by the overlap zone a special optics is used which allows shaping the laser beam into a ring shape which is then focused on the cylindrical surface and produces a radial ring weld seam simultaneously by one laser pulse. In doing this, the overlap zone is eliminated and distortion can be reduced. Radial weld seams are applied on precision samples and distortion is measured after welding. The distortion of the precision samples is measured by a tactile measuring method and a comparison of the results of welding with the ring optics to reference welds is done.

  15. Color sensing under microwaves

    Science.gov (United States)

    Choudhury, Debesh

    2013-09-01

    Inspired by recent results of artificial color due to Caulfield, we carry out intuitive experimental investigations on color sensing under microwave illumination. Experiemnts have been carried out using a Gunn diode as the microwave source and a microwave diode as a detector. More precise experimental studies have also been carried out utilizing a vector network analyzer. Preliminary results of the experiments validate the feasibility of sensing and discriminating otherwise visual colors under microwave illumination. Caulfield's presumption possibly paves the way for artificial color perception using microwaves.

  16. High brightness microwave lamp

    Science.gov (United States)

    Kirkpatrick, Douglas A.; Dolan, James T.; MacLennan, Donald A.; Turner, Brian P.; Simpson, James E.

    2003-09-09

    An electrodeless microwave discharge lamp includes a source of microwave energy, a microwave cavity, a structure configured to transmit the microwave energy from the source to the microwave cavity, a bulb disposed within the microwave cavity, the bulb including a discharge forming fill which emits light when excited by the microwave energy, and a reflector disposed within the microwave cavity, wherein the reflector defines a reflective cavity which encompasses the bulb within its volume and has an inside surface area which is sufficiently less than an inside surface area of the microwave cavity. A portion of the reflector may define a light emitting aperture which extends from a position closely spaced to the bulb to a light transmissive end of the microwave cavity. Preferably, at least a portion of the reflector is spaced from a wall of the microwave cavity. The lamp may be substantially sealed from environmental contamination. The cavity may include a dielectric material is a sufficient amount to require a reduction in the size of the cavity to support the desired resonant mode.

  17. Constraints on hidden photons from current and future observations of CMB spectral distortions

    CERN Document Server

    Kunze, Kerstin E

    2015-01-01

    A variety of beyond the standard model scenarios contain very light hidden sector U(1) gauge bosons undergoing kinetic mixing with the photon. The resulting oscillation between ordinary and hidden photons leads to spectral distortions of the cosmic microwave background. We update the bounds on the mixing parameter $\\chi_0$ and the mass of the hidden photon $m_{\\gamma'}$ for future experiments measuring CMB spectral distortions, such as PIXIE and PRISM/COrE. For $10^{-14}\\;{\\rm eV}\\lesssim m_{\\gamma'}\\lesssim 10^{-13}\\;{\\rm eV}$, we find the kinetic mixing angle $\\chi_0$ has to be less than $10^{-8}$ at 95\\% CL. These bounds are more than an order of magnitude stronger than those derived from the COBE/FIRAS data.

  18. Shedding light on the small-scale crisis with CMB spectral distortions

    Science.gov (United States)

    Nakama, Tomohiro; Chluba, Jens; Kamionkowski, Marc

    2017-06-01

    The small-scale crisis, discrepancies between observations and N -body simulations, may imply suppressed matter fluctuations on subgalactic distance scales. Such a suppression could be caused by some early-universe mechanism (e.g., broken scale invariance during inflation), leading to a modification of the primordial power spectrum at the onset of the radiation-domination era. Alternatively, it may be due to nontrivial dark-matter properties (e.g., new dark-matter interactions or warm dark matter) that affect the matter power spectrum at late times, during radiation domination, after the perturbations reenter the horizon. We show that early- and late-time suppression mechanisms can be distinguished by measurement of the μ distortion to the frequency spectrum of the cosmic microwave background. This is because the μ distortion is suppressed, if the power suppression is primordial, relative to the value expected from the dissipation of standard nearly scale-invariant fluctuations. We emphasize that the standard prediction of the μ distortion remains unchanged in late-time scenarios even if the dark-matter effects occur before or during the era (redshifts 5 ×1 04≲z ≲2 ×1 06 ) at which μ distortions are generated.

  19. Perceptual Depth Quality in Distorted Stereoscopic Images.

    Science.gov (United States)

    Wang, Jiheng; Wang, Shiqi; Ma, Kede; Wang, Zhou

    2017-03-01

    Subjective and objective measurement of the perceptual quality of depth information in symmetrically and asymmetrically distorted stereoscopic images is a fundamentally important issue in stereoscopic 3D imaging that has not been deeply investigated. Here, we first carry out a subjective test following the traditional absolute category rating protocol widely used in general image quality assessment research. We find this approach problematic, because monocular cues and the spatial quality of images have strong impact on the depth quality scores given by subjects, making it difficult to single out the actual contributions of stereoscopic cues in depth perception. To overcome this problem, we carry out a novel subjective study where depth effect is synthesized at different depth levels before various types and levels of symmetric and asymmetric distortions are applied. Instead of following the traditional approach, we ask subjects to identify and label depth polarizations, and a depth perception difficulty index (DPDI) is developed based on the percentage of correct and incorrect subject judgements. We find this approach highly effective at quantifying depth perception induced by stereo cues and observe a number of interesting effects regarding image content dependency, distortion-type dependence, and the impact of symmetric versus asymmetric distortions. Furthermore, we propose a novel computational model for DPDI prediction. Our results show that the proposed model, without explicitly identifying image distortion types, leads to highly promising DPDI prediction performance. We believe that these are useful steps toward building a comprehensive understanding on 3D quality-of-experience of stereoscopic images.

  20. Plasticity and Awareness of Bodily Distortion

    Directory of Open Access Journals (Sweden)

    Mariella Pazzaglia

    2016-01-01

    Full Text Available Knowledge of the body is filtered by perceptual information, recalibrated through predominantly innate stored information, and neurally mediated by direct sensory motor information. Despite multiple sources, the immediate prediction, construction, and evaluation of one’s body are distorted. The origins of such distortions are unclear. In this review, we consider three possible sources of awareness that inform body distortion. First, the precision in the body metric may be based on the sight and positioning sense of a particular body segment. This view provides information on the dual nature of body representation, the reliability of a conscious body image, and implicit alterations in the metrics and positional correspondence of body parts. Second, body awareness may reflect an innate organizational experience of unity and continuity in the brain, with no strong isomorphism to body morphology. Third, body awareness may be based on efferent/afferent neural signals, suggesting that major body distortions may result from changes in neural sensorimotor experiences. All these views can be supported empirically, suggesting that body awareness is synthesized from multimodal integration and the temporal constancy of multiple body representations. For each of these views, we briefly discuss abnormalities and therapeutic strategies for correcting the bodily distortions in various clinical disorders.

  1. The Thermal Distortion of a Funnel Mold

    Science.gov (United States)

    Hibbeler, Lance C.; Thomas, Brian G.; Schimmel, Ronald C.; Abbel, Gert

    2012-10-01

    This article investigates the thermal distortion of a funnel mold for continuous casting of thin slabs and explores the implications on taper and solidification of the steel shell. The three-dimensional mold temperatures are calculated using shell-mold heat flux and cooling water profiles that were calibrated with plant measurements. The thermal stresses and distorted shape of the mold are calculated with a detailed finite-element model of a symmetric fourth of the entire mold and waterbox assembly, and they are validated with plant thermocouple data and measurements of the wear of the narrow-face copper mold plates. The narrow-face mold distorts into the typical parabolic arc, and the wide face distorts into a "W" shape owing to the large variation in bolt stiffnesses. The thermal expansion of the wide face works against the applied narrow-face taper and funnel effects, so the effect of thermal distortion must be considered to accurately predict the ideal mold taper.

  2. Magnetotelluric distortions directly observed with lightning data

    Science.gov (United States)

    Hennessy, Lachlan; Macnae, James

    2017-08-01

    Galvanic distortions complicate magnetotelluric (MT) soundings. In this research, we use lightning network data to identify specific sferics in MT measurements and analyse these events on the basis of the lightning source location. Without source information, identification and removal of galvanic distortion is a fundamentally ill-posed problem, unless data are statistically decomposed into determinable and indeterminable parts. We use realistic assumptions of the earth-ionosphere waveguide propagation velocity to accurately predict the time of arrival, azimuth and amplitude for every significant sferic in our time-series data. For each sferic with large amplitude, we calculate the rotation of the electric field from the measured to the predicted arrival azimuth. This rotation of the electric field is a primary parameter of distortion. Our results demonstrate that a rudimentary model for near-surface galvanic distortion consistently fits observed electric field rotations. When local features rotate regional electric fields, then counter-rotating data to predicted arrival azimuths should correct the directional dependence of static shift. Although we used amplitude thresholds to simplify statistical processing, future developments should incorporate both signal-to-noise improvements and multisite decompositions. Lower amplitude signal may also be useful after the appropriate signal processing for noise reduction. We anticipate our approach will be useful for further work on MT distortion.

  3. Potential-well distortion and mode-mixing instability in proton machines

    Energy Technology Data Exchange (ETDEWEB)

    Ng, King-Yuen [Fermi National Accelerator Lab., Batavia, IL (United States)

    1996-08-01

    In proton machines, potential-well distortion leads to small amount of bunch lengthening with minimal head-tail asymmetry. Longitudinal mode-mixing instability occurs at higher azimuthal modes. When the driving resonance is of broad-band, the threshold corresponds to the Boussard-modified Keil-Schnell criterion for microwave instability. When the driving resonance is narrower than the bunch spectrum, the threshold corresponds to a similar criterion derived before. The thresholds are higher when the machine operates below transition. (author)

  4. A Limit on Primordial Small-Scale Magnetic Fields from CMB Distortions

    CERN Document Server

    Jedamzik, K; Olinto, A V

    2000-01-01

    Spatially varying primordial magnetic fields may be efficiently dissipated prior to the epoch of recombination due to the large viscosity of the baryon-photon fluid. We show that this dissipation may result in observable chemical potential mu and Compton y distortions in the cosmic microwave background radiation (CMB) spectrum. Current upper limits on mu and y from FIRAS constrain magnetic fields to have strength B_0 < 3\\times 10^{-8}Gauss (scaled to the present) between comoving coherence length \\approx 400 pc and primordial magnetic fields to date.

  5. A Video Watermarking Against Geometrical Distortions

    Institute of Scientific and Technical Information of China (English)

    NIUXiamu; SCHMUCKERMartin; BUSCHChristoph; SUNShenghe

    2003-01-01

    A video watermarking with robustness against frame's geometrical distortions (rotation, aspect ratio, scaling, translation shearing, and bending) is proposed. The watermark information is embedded into pixels along the temporal axis within a Watermark minimum segment (WMS). Since the geometrical distortions operations for every frame along the time axis in a video sequence are the same at a very short interval, the watermark information can be detected from watermarked frames in each WMS subjected to the distortions. Furthermore, adaptive embedding method is proposed for gaining a good quality of the watermarked video. Experimental results show that the proposed technique is robust against common attacks such as rotation, aspect ratio, scaling, translation shearing, and bending of frames, MPEG-2 lossy compression, and color-space conversion.

  6. Expertise and Processing Distorted Structure in Chess

    Directory of Open Access Journals (Sweden)

    James eBartlett

    2013-12-01

    Full Text Available A classic finding in research on human expertise and knowledge is that of enhanced memory for stimuli in a domain of expertise as compared to either stimuli outside that domain, or within-domain stimuli that have been or degraded or distorted in some way. However, we do not understand how the expert brain processes within-domain stimuli that have been distorted enough to be perceived as impossible or wrong, and yet still are perceived as within the domain (e.g., a face with the eyes, nose and mouth in the wrong positions, or a chessboard with pieces placed randomly on the board. Focusing on the domain of chess, we present new fMRI evidence that when experts view such distorted/within-domain stimuli, they engage an active search for structure – a kind of exploratory chunking – that involves a component of a prefrontal-parietal network linked to consciousness, attention and working memory.

  7. Machining distortion prediction of aerospace monolithic components

    Institute of Scientific and Technical Information of China (English)

    Yun-bo BI; Qun-lin CHENG; Hui-yue DONG; Ying-lin KE

    2009-01-01

    To predict the distortion of aerospace monolithic components.a model is established to simulate the numerical control (NC)milling process using 3D finite element method(FEM).In this model,the cutting layer is simplified firstly.Then,the models of cutting force and cutting temperature are established to gain the cutting loads,which are applied to the mesh model of the part.Finally,a prototype of machining simulation environment is developed to simulate the milling process of a spar.Key factors influencing the distortion,such as initial residual stress,cutting loads,fixture layout,cutting sequence,and tool path are considered all together.The total distortion of the spar is predicted and an experiment is conducted to validate the numerical results.It is found that the maximum discrepancy between the simulation results and experiment values is 19.0%

  8. A helically distorted MHD flux rope model

    Science.gov (United States)

    Theobald, Michael L.; Montgomery, David

    1990-01-01

    A flux rope model is proposed which has a variable degree of helical distortion from axisymmetry. The basis for this suggestion is a series of numerical and analytical investigations of magnetohydrodynamic states which result when an axial electric current is directed down on dc magnetic field. The helically distorted states involve a flow velocity and seem to be favored because of their lower rate of energy dissipation. Emphasis is on the magnetometer and particle energy analyzer traces that might be characteristic of such flux ropes. It is shown that even a fractionally small helical distortion may considerably alter the traces in minimum-variance coordinates. In short, what may be fairly common MHD processes can render a flux rope almost unrecognizable under standard diagnostics, even if the departures from axisymmetry are not great.

  9. Image Distortion of Optical Coherence Tomography

    Institute of Scientific and Technical Information of China (English)

    安源; 姚建铨

    2004-01-01

    A kind of image distortion in Optical Coherence Tomography (OCT) resulted from average refractive index changes between structures of bio-tissue is discussed for the first time.Analysis is given on following situations:1) Exact refraction index changes between microstructures;2)The gradient of average refractive index change between different tissue layers is parallel to the probe beam;3) The gradient of average refractive index change is vertical to the probe beam.The results show that the image distortion of situation 1) is usually negligible;in situation 2) there is a spread or shrink effect without relative location error; however,in situation 3) there is a significant image error inducing relative location displacement between different structures.Preliminary design to eliminate the distortion is presented,the method of which mainly based on the image classification and pixel array re-arrangement.

  10. Dynamic Inlet Distortion Prediction with a Combined Computational Fluid Dynamics and Distortion Synthesis Approach

    Science.gov (United States)

    Norby, W. P.; Ladd, J. A.; Yuhas, A. J.

    1996-01-01

    A procedure has been developed for predicting peak dynamic inlet distortion. This procedure combines Computational Fluid Dynamics (CFD) and distortion synthesis analysis to obtain a prediction of peak dynamic distortion intensity and the associated instantaneous total pressure pattern. A prediction of the steady state total pressure pattern at the Aerodynamic Interface Plane is first obtained using an appropriate CFD flow solver. A corresponding inlet turbulence pattern is obtained from the CFD solution via a correlation linking root mean square (RMS) inlet turbulence to a formulation of several CFD parameters representative of flow turbulence intensity. This correlation was derived using flight data obtained from the NASA High Alpha Research Vehicle flight test program and several CFD solutions at conditions matching the flight test data. A distortion synthesis analysis is then performed on the predicted steady state total pressure and RMS turbulence patterns to yield a predicted value of dynamic distortion intensity and the associated instantaneous total pressure pattern.

  11. Modeling the Radio Foreground for detection of CMB spectral distortions from Cosmic Dawn and Epoch of Reionization

    CERN Document Server

    Rao, Mayuri Sathyanarayana; Shankar, N Udaya; Chluba, Jens

    2016-01-01

    Cosmic baryon evolution during Cosmic Dawn and Cosmological Reionization results in spectral distortions in the cosmic microwave background (CMB) owing to redshifted 21-cm absorption and emission. These spectral features from redshifts $30 \\lesssim z \\lesssim 6$ appear at meter wavelengths ($\\lesssim200$ MHz) as a tiny CMB distortion component in addition to the Galactic and extragalactic radio sky spectrum, which is orders of magnitude brighter. These spectral distortions encode information about the thermal history of baryons and the nature and timing of the first collapsed objects. However detecting them requires methods for precise modeling of foregrounds. Here we present an improvement over previous efforts to simulate foregrounds. We adopt GMOSS, a physically motivated sky model that represents sky spectra using radiative processes to simulate realistic expectation of sky spectra over 40--200 MHz. From mock observations resulting plausible spectral shapes we demonstrate that a polynomial of at least ord...

  12. Contrast-enhanced microwave detection and treatment of breast cancer

    Science.gov (United States)

    Gao, Fuqiang

    Contrast agents and heating agents have been proposed for microwave breast tumor imaging and treatment, respectively. The dielectric properties of the tumor are altered with contrast agents or heating agents that locally accumulate in the tumor. The resulting change in dielectric properties of the tumor has the potential to enhance the sensitivity of microwave imaging of breast tumors and increase the efficiency and selectivity of microwave thermal therapy of breast tumors. This dissertation addresses several key challenges in contrast-enhanced microwave imaging and treatment of breast tumors. Carbon nanotubes (CNTs) have been shown to enhance both the relative permittivity and effective conductivity of the host medium, and are promising as theranostic (integrated therapeutic and diagnostic) agents. Thus, our properties characterization work focuses on CNT dispersions. We performed in vitro microwave dielectric properties and heating response characterization of dispersions of CNTs treated by different functionalization methods and identified a CNT formulation that is very promising as a microwave theranostic agent. Stable dispersions of CNTs with concentrations up to 20 mg/ml are obtained with this formulation, and the enhanced microwave properties of these dispersions are extraordinary compared to the control. We also conducted in vivo dielectric properties characterization of mouse tumors with intra-tumoral injections of CNT dispersions and confirmed that the presence of CNTs increases the dielectric properties of the tumor. In parallel, we developed a contrast-enhanced microwave breast tumor imaging algorithm using sparse reconstruction methods. We demonstrated that this algorithm accurately localizes small tumors in 3D numerical breast phantoms. We also demonstrated the experimental feasibility of this method using physical breast phantoms. Lastly, we studied the sensitivity of the distorted Born iterative method (DBIM) to initial guesses and developed a

  13. Using your microwave oven. Lesson 6, Microwave oven management

    OpenAIRE

    Woodard, Janice Emelie, 1929-

    1984-01-01

    Discusses cooking and reheating foods in microwave ovens, and adapting conventional recipes for the microwave. Revised Includes the publication: Adapting conventional recipes to microwave cooking : fact sheet 84 by Janice Woodard, Rebecca Lovingood, R.H. Trice.

  14. Using your microwave oven. Lesson 6, Microwave oven management

    OpenAIRE

    Woodard, Janice Emelie, 1929-

    1984-01-01

    Discusses cooking and reheating foods in microwave ovens, and adapting conventional recipes for the microwave. Revised Includes the publication: Adapting conventional recipes to microwave cooking : fact sheet 84 by Janice Woodard, Rebecca Lovingood, R.H. Trice.

  15. Optimal Risk Sharing under Distorted Probabilities

    CERN Document Server

    Ludkovski, M

    2008-01-01

    We study optimal risk sharing among $n$ agents endowed with distortion risk measures. Our model includes market frictions that can either represent linear transaction costs or risk premia charged by a clearing house for the agents. Risk sharing under third-party constraints is also considered. We obtain an explicit formula for Pareto optimal allocations. In particular, we find that a stop-loss or deductible risk sharing is optimal in the case of two agents and several common distortion functions. This extends recent result of Jouini et al. (2006) to the problem with unbounded risks and market frictions.

  16. Satellite Video Stabilization with Geometric Distortion

    Directory of Open Access Journals (Sweden)

    WANG Xia

    2016-02-01

    Full Text Available There is an exterior orientation difference in each satellite video frame, and the corresponding points have different image locations in adjacent frames images which has geometric distortion. So the projection model, affine model and other classical image stabilization registration model cannot accurately describe the relationship between adjacent frames. This paper proposes a new satellite video image stabilization method with geometric distortion to solve the problem, based on the simulated satellite video, we verify the feasibility and accuracy of proposed satellite video stabilization method.

  17. Low distortion transform for reversible watermarking.

    Science.gov (United States)

    Coltuc, Dinu

    2012-01-01

    This paper proposes a low-distortion transform for prediction-error expansion reversible watermarking. The transform is derived by taking a simple linear predictor and by embedding the expanded prediction error not only into the current pixel but also into its prediction context. The embedding ensures the minimization of the square error introduced by the watermarking. The proposed transform introduces less distortion than the classical prediction-error expansion for complex predictors such as the median edge detector or the gradient-adjusted predictor. Reversible watermarking algorithms based on the proposed transform are analyzed. Experimental results are provided.

  18. Spherical Parameterization Balancing Angle and Area Distortions.

    Science.gov (United States)

    Nadeem, Saad; Su, Zhengyu; Zeng, Wei; Kaufman, Arie; Gu, Xianfeng

    2017-06-01

    This work presents a novel framework for spherical mesh parameterization. An efficient angle-preserving spherical parameterization algorithm is introduced, which is based on dynamic Yamabe flow and the conformal welding method with solid theoretic foundation. An area-preserving spherical parameterization is also discussed, which is based on discrete optimal mass transport theory. Furthermore, a spherical parameterization algorithm, which is based on the polar decomposition method, balancing angle distortion and area distortion is presented. The algorithms are tested on 3D geometric data and the experiments demonstrate the efficiency and efficacy of the proposed methods.

  19. Angular dependence of primordial trispectra and CMB spectral distortions

    Science.gov (United States)

    Shiraishi, Maresuke; Bartolo, Nicola; Liguori, Michele

    2016-10-01

    Under the presence of anisotropic sources in the inflationary era, the trispectrum of the primordial curvature perturbation has a very specific angular dependence between each wavevector that is distinguishable from the one encountered when only scalar fields are present, characterized by an angular dependence described by Legendre polynomials. We examine the imprints left by curvature trispectra on the TTμ bispectrum, generated by the correlation between temperature anisotropies (T) and chemical potential spectral distortions (μ) of the Cosmic Microwave Background (CMB). Due to the angular dependence of the primordial signal, the corresponding TTμ bispectrum strongly differs in shape from TTμ sourced by the usual gNL or τNL local trispectra, enabling us to obtain an unbiased estimation. From a Fisher matrix analysis, we find that, in a cosmic-variance-limited (CVL) survey of TTμ, a minimum detectable value of the quadrupolar Legendre coefficient is d2 ~ 0.01, which is 4 orders of magnitude better than the best value attainable from the TTTT CMB trispectrum. In the case of an anisotropic inflationary model with a f(phi)F2 interaction (coupling the inflaton field phi with a vector kinetic term F2), the size of the curvature trispectrum is related to that of quadrupolar power spectrum asymmetry, g*. In this case, a CVL measurement of TTμ makes it possible to measure g* down to 10‑3.

  20. Angular dependence of primordial trispectra and CMB spectral distortions

    CERN Document Server

    Shiraishi, Maresuke; Liguori, Michele

    2016-01-01

    Under the presence of anisotropic sources in the inflationary era, the trispectrum of the primordial curvature perturbation is sensitive to the angles between each wave vector. We examine the imprints left by curvature trispectra, in which the angular dependence is described by Legendre polynomials, on the $TT\\mu$ bispectrum, generated by the correlation between temperature anisotropies (T) and chemical potential spectral distortions ($\\mu$) of the Cosmic Microwave Background (CMB). Due to the angular dependence of the primordial signal, the corresponding $TT\\mu$ bispectrum strongly differs in shape from $TT\\mu$ sourced by the usual $g_{\\rm NL}$ or $\\tau_{\\rm NL}$ local trispectra, enabling us to obtain an unbiased estimation. From a Fisher matrix analysis, we find that, in a cosmic-variance-limited (CVL) survey of $TT\\mu$, a minimum detectable value of the quadrupolar Legendre coefficient is $d_2 \\sim 0.01$, which is 4 orders of magnitude better than the best value attainable from the $TTTT$ CMB trispectrum....

  1. Microwave Spectrometry for the Evaluation of the Dimensions of Coronary Stents

    CERN Document Server

    Arauz-Garofalo, Gianluca; Rodriguez-Leor, Oriol; Bayes-Genis, Antoni; O'Callaghan, Juan M; García-Santiago, Antoni; Tejada, Javier

    2012-01-01

    We study microwave scattering spectra of metallic stents in open air. We show that they behave like dipole antennas in terms of microwave scattering and they exhibit characteristic resonant frequencies for a given nominal size. We obtain a fair agreement between measured frequencies and the values provided by a theoretical model for dipole antennas. This fact opens the door to obtaining methods to detect structural distortions of stents within in vitro conditions. Finally we discuss the in vivo applicability of the suggested method in terms of our theoretical model and the skin depth of microwaves in biological tissues.

  2. Microwave and RF engineering

    CERN Document Server

    Sorrentino, Roberto

    2010-01-01

    An essential text for both students and professionals, combining detailed theory with clear practical guidance This outstanding book explores a large spectrum of topics within microwave and radio frequency (RF) engineering, encompassing electromagnetic theory, microwave circuits and components. It provides thorough descriptions of the most common microwave test instruments and advises on semiconductor device modelling. With examples taken from the authors' own experience, this book also covers:network and signal theory;electronic technology with guided electromagnetic pr

  3. Advanced microwave processing concepts

    Energy Technology Data Exchange (ETDEWEB)

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymeric materials. The variable frequency microwave furnace, whose initial conception and design was funded by the AIM Materials Program, allows the authors, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of various thermoset resins will be studied because it holds the potential of in-situ curing of continuous-fiber composites for strong, lightweight components or in-situ curing of adhesives, including metal-to-metal. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  4. Advanced microwave processing concepts

    Energy Technology Data Exchange (ETDEWEB)

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L. [Oak Ridge National Laboratory, TN (United States)

    1995-05-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymer composites. The variable frequency microwave furnace, whose initial conception and design was funded by the AIC Materials Program, will allow us, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of thermoset resins will be studied because it hold the potential of in-situ curing of continuous-fiber composites for strong, lightweight components. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  5. Advances in microwaves 3

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 3 covers the advances and applications of microwave signal transmission and Gunn devices. This volume contains six chapters and begins with descriptions of ground-station antennas for space communications. The succeeding chapters deal with beam waveguides, which offer interesting possibilities for transmitting microwave energy, as well as with parallel or tubular beams from antenna apertures. A chapter discusses the electron transfer mechanism and the velocity-field characteristics, with a particular emphasis on the microwave properties of Gunn oscillators. The l

  6. Distorted waves in pion- (Kaon-) nucleus reactions

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, E.R.; Thaler, R.M.

    1978-10-02

    The difference between the Schroedinger and Klein-Gordon wave functions is calculated for 100--200-MeV pions. The same optical-model potential is used in each case. The differences in the distorted waves so calculated are shown to be significant even though the elastic scattering phase shifts re nearly identical.

  7. determination of determination of total harmonic distortion

    African Journals Online (AJOL)

    eobe

    Harmonic Distortion (THD) of the Distribution lines in the 33kV distri .... guidelines based on industrial distribution system design. IEEE 519-1992 defines ..... studies and also reviewed issues related to the concept. The results of power flow and ...

  8. Distortion control of conjugacies between quadratic polynomials

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We use a new type of distortion control of univalent functions to give an alternative proof of Douady-Hubbard’s ray-landing theorem for quadratic Misiurewicz polynomials. The univalent maps arise from Thurston’s iterated algorithm on perturbation of such polynomials.

  9. Rate-distortion theory and human perception.

    Science.gov (United States)

    Sims, Chris R

    2016-07-01

    The fundamental goal of perception is to aid in the achievement of behavioral objectives. This requires extracting and communicating useful information from noisy and uncertain sensory signals. At the same time, given the complexity of sensory information and the limitations of biological information processing, it is necessary that some information must be lost or discarded in the act of perception. Under these circumstances, what constitutes an 'optimal' perceptual system? This paper describes the mathematical framework of rate-distortion theory as the optimal solution to the problem of minimizing the costs of perceptual error subject to strong constraints on the ability to communicate or transmit information. Rate-distortion theory offers a general and principled theoretical framework for developing computational-level models of human perception (Marr, 1982). Models developed in this framework are capable of producing quantitatively precise explanations for human perceptual performance, while yielding new insights regarding the nature and goals of perception. This paper demonstrates the application of rate-distortion theory to two benchmark domains where capacity limits are especially salient in human perception: discrete categorization of stimuli (also known as absolute identification) and visual working memory. A software package written for the R statistical programming language is described that aids in the development of models based on rate-distortion theory.

  10. A rate distortion approach to protein symmetry.

    Science.gov (United States)

    Wallace, Rodrick

    2010-08-01

    A spontaneous symmetry breaking argument is applied to the problem of protein folding, via a rate distortion analysis of the relation between genome coding and the final condensation of the protein molten globule that is, in spirit, analogous to Tlusty's (2007) exploration of the evolution of the genetic code. In the 'energy' picture, the average distortion between codon message and final protein structure, under constraints driven by evolutionary selection, serves as a temperature analog, so that low values limit the possible distribution of protein forms, producing the canonical folding funnel. A dual 'developmental' perspective sees the rate distortion function itself as the temperature analog, and permits incorporation of chaperons or toxic exposures as catalysts, driving the system to different possible outcomes or affecting the rate of convergence. The rate distortion function appears constrained by the availability of metabolic free energy, with implications for prebiotic evolution, and a nonequilibrium empirical Onsager treatment provides an adaptable statistical model that can be fitted to data, in the same manner as a regression equation. In sum, mechanistic models of protein folding fail to account for the observed spectrum of protein folding and aggregation disorders, suggesting that a biologically based cognitive paradigm describing folding will be needed for understanding the etiology, prevention, and treatment of these diseases. The developmental formalism introduced here may contribute substantially to such a paradigm.

  11. Solid Waste Market Distortions and Recycling

    NARCIS (Netherlands)

    Bartelings, H.; Dellink, R.B.; Ierland, van E.C.

    2006-01-01

    Solid waste management is an important topic in environmental economics, and there is a need for providing better incentives to further optimize the chain of materials and waste. We investigate market distortions caused by flat fee pricing in the solid waste market and we show how flat fee pricing

  12. Modelling the Perceptual Components of Loudspeaker Distortion

    DEFF Research Database (Denmark)

    Olsen, Sune L.; Agerkvist, Finn T.; MacDonald, Ewen;

    2016-01-01

    While non-linear distortion in loudspeakers decreases audio quality, the perceptual consequences can vary substantially. This paper investigates the metric Rnonlin [1] which was developed to predict subjective measurements of sound quality in nonlinear systems. The generalisability of the metric...

  13. Solid Waste Market Distortions and Recycling

    NARCIS (Netherlands)

    Bartelings, H.; Dellink, R.B.; Ierland, van E.C.

    2006-01-01

    Solid waste management is an important topic in environmental economics, and there is a need for providing better incentives to further optimize the chain of materials and waste. We investigate market distortions caused by flat fee pricing in the solid waste market and we show how flat fee pricing i

  14. Audible Aliasing Distortion in Digital Audio Synthesis

    Directory of Open Access Journals (Sweden)

    J. Schimmel

    2012-04-01

    Full Text Available This paper deals with aliasing distortion in digital audio signal synthesis of classic periodic waveforms with infinite Fourier series, for electronic musical instruments. When these waveforms are generated in the digital domain then the aliasing appears due to its unlimited bandwidth. There are several techniques for the synthesis of these signals that have been designed to avoid or reduce the aliasing distortion. However, these techniques have high computing demands. One can say that today's computers have enough computing power to use these methods. However, we have to realize that today’s computer-aided music production requires tens of multi-timbre voices generated simultaneously by software synthesizers and the most of the computing power must be reserved for hard-disc recording subsystem and real-time audio processing of many audio channels with a lot of audio effects. Trivially generated classic analog synthesizer waveforms are therefore still effective for sound synthesis. We cannot avoid the aliasing distortion but spectral components produced by the aliasing can be masked with harmonic components and thus made inaudible if sufficient oversampling ratio is used. This paper deals with the assessment of audible aliasing distortion with the help of a psychoacoustic model of simultaneous masking and compares the computing demands of trivial generation using oversampling with those of other methods.

  15. Artificial color perception using microwaves

    CERN Document Server

    Choudhury, Debesh

    2013-01-01

    We report the feasibility of artificial color perception under microwave illumination using a standard microwave source and an antenna. We have sensed transmitted microwave power through color objects and have distinguished the colors by analyzing the sensed transmitted power. Experiments are carried out using a Gunn diode as the microwave source, some colored liquids as the objects and a microwave diode as the detector. Results are presented which open up an unusual but new way of perceiving colors using microwaves.

  16. NOVEL MICROWAVE FILTER DESIGN TECHNIQUES.

    Science.gov (United States)

    ELECTROMAGNETIC WAVE FILTERS, MICROWAVE FREQUENCY, PHASE SHIFT CIRCUITS, BANDPASS FILTERS, TUNED CIRCUITS, NETWORKS, IMPEDANCE MATCHING , LOW PASS FILTERS, MULTIPLEXING, MICROWAVE EQUIPMENT, WAVEGUIDE FILTERS, WAVEGUIDE COUPLERS.

  17. Highly linear and transparent 3-18 GHz optical microwave link

    DEFF Research Database (Denmark)

    Nielsen, Torben Nørskov; Gliese, Ulrik Bo; Christensen, T.;

    1994-01-01

    A highly linear optical microwave link transmitter based on heterodyne phase-locked DFB lasers is presented. The transmitter is transparent for FM and PM input signals with carrier frequencies ranging from 3-18 GHz. Distortion-free transmission of a 7.6 GHz FM PAL video signal over 25 km of optical...

  18. Microwave spectrum, structure, dipole moment, and barrier to internal rotation of methylthioethyne

    NARCIS (Netherlands)

    Engelsen, D. den

    1967-01-01

    The microwave absorption spectrum is reported as well as rotational constants, dipole moment components, and centrifugal distortion constants of methylthioethyne. The spectra of two isotopic species of methylthioethyne were measured, namely, HCC---32SCH3 and HCC---34SCH3; the determination of the mo

  19. Quality Evaluation and Nonuniform Compression of Geometrically Distorted Images Using the Quadtree Distortion Map

    Directory of Open Access Journals (Sweden)

    Cristina Costa

    2004-09-01

    Full Text Available The paper presents an analysis of the effects of lossy compression algorithms applied to images affected by geometrical distortion. It will be shown that the encoding-decoding process results in a nonhomogeneous image degradation in the geometrically corrected image, due to the different amount of information associated to each pixel. A distortion measure named quadtree distortion map (QDM able to quantify this aspect is proposed. Furthermore, QDM is exploited to achieve adaptive compression of geometrically distorted pictures, in order to ensure a uniform quality on the final image. Tests are performed using JPEG and JPEG2000 coding standards in order to quantitatively and qualitatively assess the performance of the proposed method.

  20. Sensitivity Limits of Deep Average Broadband Microwave and Mm-Wave Spectra

    Science.gov (United States)

    Muckle, Matt T.; Zaleski, Daniel P.; Steber, Amanda; Harris, Brent; Pate, Brooks H.

    2012-06-01

    High-speed digitizers have enabled the field of broadband molecular rotational spectroscopy at microwave-to-THz frequencies. Improvements in data throughput from these digitizers makes it feasible to perform deep averages (often more than 1 million time-domain averages of the free induction decay) to increase the measurement sensitivity. The use of broadband signal detection introduces new issues that are key for determining the practical sensitivity limits of these spectrometers. The practical limit on spectrometer sensitivity is often set by the number of spurious signals that are generated by the molecular signals themselves. For example, in cases where the molecular signals are down converted prior to digitization, the spectral purity of the local oscillator is crucial with spurious frequencies introducing spectral images. It is also possible to generate new local oscillator frequencies within the broadband mixers typically used in the broadband down conversion. A second issue it the potential for a vast number of intermodulation (IM) spurious signals resulting from the beating of two strong molecular transitions. This beat frequency can subsequently modulate all other molecular signals adding sidebands to all transitions at the beat frequency of the transition pair. This talk will summarize our experience with the spurious signal levels coming from these effects and the strategies we have adopted to minimize spurious signals in spectra where high sensitivity is necessary.

  1. The Cosmic Microwave Background

    OpenAIRE

    Silk, Joseph

    2002-01-01

    This set of lectures provides an overview of the basic theory and phenomenology of the cosmic microwave background. Topics include a brief historical review; the physics of temperature and polarization fluctuations; acoustic oscillations of the primordial plasma; the space of inflationary cosmological models; current and potential constraints on these models from the microwave background; and constraints on inflation.

  2. Microwave Enhanced Reactive Distillation

    NARCIS (Netherlands)

    Altman, E.

    2011-01-01

    The application of electromagnetic irradiation in form of microwaves (MW) has gathered the attention of the scientific community in recent years. MW used as an alternative energy source for chemical syntheses (microwave chemistry) can provide clear advantages over conventional heating methods in ter

  3. Microwave disinfection of maxillary and mandibular denture bases contaminated with Candida Albican.

    Science.gov (United States)

    Bamigboye, S A; Dosumu, O O; Ajayi, D M

    2015-09-01

    Oral environment is not sterile, and dentures worn by the patients can be infected and therefore needs disinfection. Solution disinfectants such as sodium hypochlorite and glutaraldehyde can be used but they have side effects. Microwave disinfection method is more recent, however, there are conflicting reports at the moment on the appropriate power and time regimen for disinfection of denture. To determine the power and time regimen at which the disinfection of dentures can be achieved using microwave. Forty-five acrylic denture bases were fabricated for each of the jaws and infected with solution of a stock Candida albicans and 30 infected bases were employed as control. These were placed in normal saline and then subjected to different microwave power and time regimen. Aliquots from these post-microwave solution were titrated against sabauraud agar which was subsequently incubated at 37 degrees C for 48 hours. The agar were examined for candida growth. The denture bases subjected to microwave disinfection at 350W showed Candida growth after microwave treatment irrespective of the time employed. Conversely, those microwaved at 650W and 690W for four and six minutes showed no microbial growth. The microwave regimen of 650W at 4 and 6 minutes completely disinfected the denture bases. Disinfection at higher microwave energy should be done with caution as distortion of the denture may occur.

  4. Tests of the CMB temperature-redshift relation, CMB spectral distortions and why adiabatic photon production is hard

    Science.gov (United States)

    Chluba, J.

    2014-09-01

    In the expanding Universe, the average temperature of the cosmic microwave background (CMB) is expected to depend like TCMB ∝ (1 + z) on redshift z. Adiabatic photon production (or destruction) or deviations from isotropy and homogeneity could modify this scaling and several observational tests have been carried out in response. Here, we explain why `adiabatic' conditions are extremely difficult to establish in the redshift range targeted by these tests. Thus, instead of leading to a simple rescaling of the CMB temperature, a spectral distortion should be produced, which can be constrained using COBE/FIRAS. For scenarios with late photon production, tests of the temperature-redshift relation (TRR) should therefore be reinterpreted as weak spectral distortion limits, directly probing the energy dependence of the photon production process. For inhomogeneous cosmologies, an average y-type distortion is produced, but this type of distortion can be created in several other ways. Here, we briefly discuss possible effects that may help disentangling different contributions to the distortion signal, finding this to be very challenging. We furthermore argue that tests of the TRR using the Sunyaev-Zeldovich effect have limited applicability and that for non-gravitational changes to the TRR, the CMB anisotropy spectrum should exhibit an additional y-type dependence.

  5. The Euclidean distortion of the lamplighter group

    CERN Document Server

    Austin, Tim; Valette, Alain

    2007-01-01

    We show that the cyclic lamplighter group $C_2 \\bwr C_n$ embeds into Hilbert space with distortion ${\\rm O}(\\sqrt{\\log n})$. This matches the lower bound proved by Lee, Naor and Peres in \\cite{LeeNaoPer}, answering a question posed in that paper. Thus the Euclidean distortion of $C_2 \\bwr C_n$ is $\\Theta(\\sqrt{\\log n})$. Our embedding is constructed explicitly in terms of the irreducible representations of the group. Since the optimal Euclidean embedding of a finite group can always be chosen to be equivariant, as shown by Aharoni, Maurey and Mityagin \\cite{AhaMauMit} and by Gromov (see \\cite{deCTesVal}), such representation-theoretic considerations suggest a general tool for obtaining upper and lower bounds on Euclidean embeddings of finite groups.

  6. Lawful Distortion of Consumers’ Economic Behaviour

    DEFF Research Database (Denmark)

    Trzaskowski, Jan

    2016-01-01

    The Unfair Commercial Practices Directive prohibits unfair business-to-consumer commercial practices with a view to protect consumers’ economic interests. In a market economy such regulation cannot protect the economic interests of all consumers in all situations – there must inevitably be some...... ‘collateral damage’. In that vein this article discusses situations where consumers may have their economic behaviour distorted by commercial practices that are not unfair under the Directive. It is expected that many consumers will make relatively good decisions most of the time...... Visitors’). The article suggests how behavioural sciences may be applied to understand these situations in order to protect more consumers from having their economic behaviour distorted by commercial practices. It is suggested that per se prohibitions may be advantageous in some instances as long...

  7. Lawful Distortion of Consumers’ Economic Behaviour

    DEFF Research Database (Denmark)

    Trzaskowski, Jan

    2016-01-01

    ‘collateral damage’. In that vein this article discusses situations where consumers may have their economic behaviour distorted by commercial practices that are not unfair under the Directive. It is expected that many consumers will make relatively good decisions most of the time...... Visitors’). The article suggests how behavioural sciences may be applied to understand these situations in order to protect more consumers from having their economic behaviour distorted by commercial practices. It is suggested that per se prohibitions may be advantageous in some instances as long......The Unfair Commercial Practices Directive prohibits unfair business-to-consumer commercial practices with a view to protect consumers’ economic interests. In a market economy such regulation cannot protect the economic interests of all consumers in all situations – there must inevitably be some...

  8. Engaging distortions: are we idealizing marriage?

    Science.gov (United States)

    Bonds-Raacke, J M; Bearden, E S; Carriere, N J; Anderson, E M; Nicks, S D

    2001-03-01

    The present study was an investigation of the premarital status of engagement in terms of relationship satisfaction and marital expectations using the Evaluation and Nurturing Relationship Issues, Communication and Happiness (ENRICH) Marital Satisfaction Scale (EMS) and its two subscales of Idealistic Distortion (ID) and Marital Satisfaction (MS) (D. G. Fournier, D. H. Olson, & J. M. Druckman, 1983). There were 104 students (23 men and 81 women), of which 15 were married, 19 were engaged, and 70 had extended dating relationships. On average, participants had been in the relationship for 3.8 years, and the mean age was 22 years. Results demonstrated that individuals engaged to be married had significantly higher idealistic distortion scores (M = 86.89) than did either married individuals (M = 56.67) or those in extended dating relationships (M = 61.19). Finally, a negative relation was found between length of relationships and marital satisfaction subscores. Results are discussed in light of factors contributing to such idealized thinking.

  9. Flow distortion on boom mounted cup anemometers

    DEFF Research Database (Denmark)

    Lindelöw, Per Jonas Petter; Friis Pedersen, Troels; Gottschall, Julia

    In this report we investigate on wind direction dependent errors in the measurement of the horizontal wind speed by boom mounted cup anemometers. The boom mounting on the studied lattice tower is performed according to IEC standard design rules, yet, larger deviations than predicted by flow models...... are observed. The errors on the measurements are likely caused by an underestimation of the flow distortions around the tower. In this paper an experimental method for deriving a correction formula and an in-field calibration is suggested. The method is based on measurements with two cup anemometers mounted...... in the measurement of wind turbine power performance, wind resource assessment and for providing purposeful in-field comparisons between different sensors, e.g. lidar anemometers. With the proposed method, direction dependent errors can be extracted and the mast flow distortion effect on the wind measurements...

  10. Distorted representation in visual tourism research

    DEFF Research Database (Denmark)

    Jensen, Martin Trandberg

    2016-01-01

    Tourism research has recently been informed by non-representational theories to highlight the socio-material, embodied and heterogeneous composition of tourist experiences. These advances have contributed to further reflexivity and called for novel ways to animate representations. On this backgro......Tourism research has recently been informed by non-representational theories to highlight the socio-material, embodied and heterogeneous composition of tourist experiences. These advances have contributed to further reflexivity and called for novel ways to animate representations....... On this background, this paper develops the notion ‘distorted representation’ to illustrate that blurred and obscure photos can in fact be intelligible and sensible in understanding tourism. Through an exploration of the overwhelmed and unintended practices of visual fieldwork, distorted representation illustrates...

  11. Dynamics of a distorted diamond chain

    Science.gov (United States)

    Mikeska, H.-J.; Luckmann, C.

    2008-02-01

    We present results on the dynamics of the distorted diamond chain, S=1/2 dimers alternating with single spins 1/2 and exchange couplings J1 and J3 in between. The dynamics in the spin fluid (SF) and tetramer-dimer (TD) phases is investigated numerically by exact diagonalization for up to 24 spins. Representative excitation spectra are presented both for zero magnetic field and in the 1/3 plateau phase and the relevant parameters are determined across the phase diagram. The behavior across the SF-TD phase transition line is discussed for the specific heat and for excitation spectra. The relevance of the distorted diamond chain model for the Cu3(CO3)2(OH)2 (azurite) material is discussed with particular emphasis on inelastic neutron scattering experiments; the recent suggestion of one possibly ferromagnetic coupling constant is not confirmed.

  12. Body image distortions in healthy adults.

    Science.gov (United States)

    Fuentes, Christina T; Longo, Matthew R; Haggard, Patrick

    2013-10-01

    Distortions of body image have often been investigated in clinical disorders. Much of this literature implicitly assumes healthy adults maintain an accurate body image. We recently developed a novel, implicit, and quantitative measure of body image - the Body Image Task (BIT). Here, we report a large-scale analysis of performance on this task by healthy adults. In both an in-person and an online version of the BIT, participants were presented with an image of a head as an anchoring stimulus on a computer screen, and told to imagine that the head was part of a mirror image of themselves in a standing position. They were then instructed to judge where, relative to the head, each of several parts of their body would be located. The relative positions of each landmark can be used to construct an implicit perceptual map of bodily structure. We could thus measure the internally-stored body image, although we cannot exclude contributions from other representations. Our results show several distortions of body image. First, we found a large and systematic over-estimation of width relative to height. These distortions were similar for both males and females, and did not closely track the idiosyncrasies of individual participant's own bodies. Comparisons of individual body parts showed that participants overestimated the width of their shoulders and the length of their upper arms, relative to their height, while underestimating the lengths of their lower arms and legs. Principal components analysis showed a clear spatial structure to the distortions, suggesting spatial organisation and segmentation of the body image into upper and lower limb components that are bilaterally integrated. These results provide new insight into the body image of healthy adults, and have implications for the study and rehabilitation of clinical populations. © 2013.

  13. MEMORY DISTORTIONS IN THE RESEARCH OF EMOTIONS

    OpenAIRE

    Ana Genc

    2015-01-01

    The memories of one’s life, or autobiographical memories, are transitory dynamic mental constructions. The human memory is both solid and fragile. We own durable and lasting traces of many events, but also we can forget other events just moments after they occured. Our memories of past experiences are never exact reproductions of the original, initial events. Besides the memory biases that are related to details about past happenings, distortions are also present in the remembering of emotion...

  14. The microwave absorption of ceramic-cup microwave ion source

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An experiment system of ceramic-cup microwave ion source has been built here. Its microwave absorption efficiency as a function of the magnetic field and the pressure is presented. When the microwave incident power is 300~500W the microwave absorption efficiencies are more than 90% if the system is optimized and the magnetic field at the microwave window is 0.095T.

  15. Axion production and CMB spectral distortion in cosmological tangled magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Ejlli, Damian [INFN Laboratori Nazionali del Gran Sasso, Theory group, Assergi, L' Aquila (Italy); Novosibirsk State University, Department of Physics, Novosibirsk (Russian Federation)

    2015-08-15

    Axion production due to photon-axion mixing in tangled magnetic fields prior to the recombination epoch and magnetic field damping can generate cosmic microwave background (CMB) spectral distortions. In particular, the contribution of both processes to the CMB μ distortion in the case of resonant photon-axion mixing is studied. Assuming that the magnetic field power spectrum is approximated by a power law, P{sub B}(k)∝k{sup n} with spectral index n, it is shown that for magnetic field cut-off scales 172.5 pc ≤ λ{sub B} ≤ 4 x 10{sup 3} pc, the axion contribution to the CMB μ distortion is subdominant in comparison with magnetic field damping in the cosmological plasma. Using the COBE upper limit on μ and for the magnetic field scale λ{sub B} ≅ 415 pc, a weaker limit in comparison with other studies on the magnetic field strength (B{sub 0} ≤ 8.5 @ x 10{sup -8} G) up to a factor 10 for the DFSZ axion model and axion mass m{sub a} ≥ 2.6 @ x 10{sup -6} eV is found. A forecast for the expected sensitivity of PIXIE/PRISM on μ is also presented. (orig.)

  16. Constraints on gravitino decay and the scale of inflation using CMB spectral distortions

    Science.gov (United States)

    Dimastrogiovanni, Emanuela; Krauss, Lawrence M.; Chluba, Jens

    2016-07-01

    If local supersymmetry is the correct extension of the standard model of particle physics, then following inflation the early Universe would have been populated by gravitinos produced from scatterings in the hot plasma during reheating. Their abundance is directly related to the magnitude of the reheating temperature. The gravitino lifetime is fixed as a function of its mass, and for gravitinos with lifetimes longer than the age of the Universe at redshift z ≃2 ×1 06 (or roughly 6 ×1 06 s ), decay products can produce spectral distortion of the cosmic microwave background. Currently available COBE/FIRAS limits on spectral distortion can, in certain cases, already be competitive with respect to cosmological constraints from primordial nucleosynthesis for some gravitino decay scenarios. We show how the sensitivity limits on μ and y distortions that can be reached with current technology will improve constraints and possibly rule out a significant portion of the parameter space for gravitino masses and inflation reheating temperatures.

  17. Distortion effects in a switch array UWB radar for time-lapse imaging of human heartbeats

    Science.gov (United States)

    Brovoll, Sverre; Berger, Tor; Aardal, Åyvind; Lande, Tor S.; Hamran, Svein-Erik

    2014-05-01

    Cardiovascular diseases (CVD) are a major cause of deaths all over the world. Microwave radar can be an alternative sensor for heart diagnostics and monitoring in modern healthcare that aids early detection of CVD symptoms. In this paper measurements from a switch array radar system are presented. This UWB system operates below 3 GHz and does time-lapse imaging of the beating heart inside the human body. The array consists of eight fat dipole elements. With a switch system, every possible sequence of transmit/receive element pairs can be selected to build a radar image from the recordings. To make the radar waves penetrate the human tissue, the antenna array is placed in contact with the body. Removal of the direct signal leakage through the antennas and body surface are done by high-pass (HP) filtering of the data prior to image processing. To analyze the results, measurements of moving spheres in air and simulations are carried out. We see that removal of the direct signal introduces amplitude distortion in the images. In addition, the effect of small target motion between the collection times of data from the individual elements is analyzed. With low pulse repetition frequency (PRF) this motion will distort the image. By using data from real measurements of heart motion in simulations, we analyze how the PRF and the antenna geometry influence this distortions.

  18. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  19. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, a reduction in reaction time from 10 minutes to 1 minute, maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  20. Distortion Contribution Analysis with the Best Linear Approximation

    OpenAIRE

    Cooman, Adam; Bronders, Piet; Peumans, Dries; Vandersteen, Gerd; Rolain, Yves

    2016-01-01

    A Distortion Contribution Analysis (DCA) obtains the distortion at the output of an analog electronic circuit as a sum of distortion contributions of its sub-circuits. Similar to a noise analysis, a DCA helps a designer to pinpoint the actual source of the distortion. Classically, the DCA uses the Volterra theory to model the circuit and its sub-circuits. This DCA has been proven useful for small circuits or heavily simplified examples. In more complex circuits however, the amount of contribu...

  1. Thermal distortion modeling of mirrors based on experimental data.

    Science.gov (United States)

    Gierloff, J J

    1981-04-01

    Mirrors are modeled to match test results from the Thermal Distortion Test Facility (TDTF) at Kirtland AFB, Albuquerque, N.M. The model allows distortions resulting from realistic beam profiles to be accurately calculated from a closed-form five-parameter equation. The basic modeling concepts as well as the model's capabilities are discussed. A comparison of model distortion predictions with observed distortions resulting from a high-energy laser beam is made.

  2. Artificial color perception using microwaves

    OpenAIRE

    Choudhury, Debesh; Caulfield, H. John

    2013-01-01

    We report the feasibility of artificial color perception under microwave illumination using a standard microwave source and an antenna. We have sensed transmitted microwave power through color objects and have distinguished the colors by analyzing the sensed transmitted power. Experiments are carried out using a Gunn diode as the microwave source, some colored liquids as the objects and a microwave diode as the detector. Results are presented which open up an unusual but new way of perceiving...

  3. Advances in microwaves 4

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 4 covers some innovations in the devices and applications of microwaves. This volume contains three chapters and begins with a discussion of the application of microwave phasers and time delay elements as beam steering elements in array radars. The next chapter provides first an overview of the technical aspects and different types of millimeter waveguides, followed by a survey of their application to railroads. The last chapter examines the general mode of conversion properties of nonuniform waveguides, such as waveguide tapers, using converted Maxwell's equatio

  4. Integrated microwave photonics

    CERN Document Server

    Marpaung, David; Heideman, Rene; Leinse, Arne; Sales, Salvador; Capmany, Jose

    2012-01-01

    Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A particular aspect that recently gains significant interests is the use of photonic integrated circuit (PIC) technology in the MWP field for enhanced functionalities and robustness as well as the reduction of size, weight, cost and power consumption. This article reviews the recent advances in this emerging field which is dubbed as integrated microwave photonics. Key integrated MWP technologies are reviewed and the prospective of the field is discussed.

  5. Advances in microwaves

    CERN Document Server

    Young, Leo

    1967-01-01

    Advances in Microwaves, Volume 2 focuses on the developments in microwave solid-state devices and circuits. This volume contains six chapters that also describe the design and applications of diplexers and multiplexers. The first chapter deals with the parameters of the tunnel diode, oscillators, amplifiers and frequency converter, followed by a simple physical description and the basic operating principles of the solid state devices currently capable of generating coherent microwave power, including transistors, harmonic generators, and tunnel, avalanche transit time, and diodes. The next ch

  6. The Microwave Hall Effect

    OpenAIRE

    2015-01-01

    This paper describes a simple microwave apparatus to measure the Hall effect in semiconductor wafers. The advantage of this technique is that it does not require contacts on the sample or the use of a resonant cavity. Our method consists of placing the semiconductor wafer into a slot cut in an X-band (8 - 12 GHz) waveguide series tee, injecting microwave power into the two opposite arms of the tee, and measuring the microwave output at the third arm. A magnetic field applied perpendicular to ...

  7. Monolithic microwave integrated circuits

    Science.gov (United States)

    Pucel, R. A.

    Monolithic microwave integrated circuits (MMICs), a new microwave technology which is expected to exert a profound influence on microwave circuit designs for future military systems as well as for the commercial and consumer markets, is discussed. The book contains an historical discussion followed by a comprehensive review presenting the current status in the field. The general topics of the volume are: design considerations, materials and processing considerations, monolithic circuit applications, and CAD, measurement, and packaging techniques. All phases of MMIC technology are covered, from design to testing.

  8. Rate distortion and denoising of individual data using Kolmogorov complexity

    NARCIS (Netherlands)

    Vereshchagin, N.K.; Vitányi, P.M.B.

    2010-01-01

    We examine the structure of families of distortion balls from the perspective of Kolmogorov complexity. Special attention is paid to the canonical rate-distortion function of a source word which returns the minimal Kolmogorov complexity of all distortion balls containing that word subject to a bound

  9. Appraisal Distortions and Intimate Partner Violence: Gender, Power, and Interaction

    Science.gov (United States)

    Whiting, Jason B.; Oka, Megan; Fife, Stephen T.

    2012-01-01

    In relationships characterized by control, abuse, or violence, many appraisal distortions occur including denial and minimization. However, the nature of the distortion varies depending on the individual's role in the relationship (i.e., abuser or victim). Reducing these distortions is an important component in treatment success and involves…

  10. Cognitive Distortions and Autonomy among Chinese University Students

    Science.gov (United States)

    Zhang, Li-fang

    2008-01-01

    The purpose of this study was to examine the roles of university students' cognitive distortions in their sense of autonomy. One hundred and three third-year university students from Shanghai, The People's Republic of China, responded to the Cognitive Distortion Scales [Briere, J. (2000). "Cognitive Distortion Scales: Professional…

  11. High-order-harmonic generation from field-distorted orbitals

    DEFF Research Database (Denmark)

    Spiewanowski, Maciek; Etches, Adam; Madsen, Lars Bojer

    2013-01-01

    We investigate the effect on high-order-harmonic generation of the distortion of molecular orbitals by the driving laser field. Calculations for high-order-harmonic generation including orbital distortion are performed for N2. Our results allow us to suggest that field distortion is the reason why...

  12. The Perceptual Distortion of Height in Intercollegiate Debate.

    Science.gov (United States)

    Hensley, Wayne E.; Angoli, Marilyn

    Both balance and reinforcement theories were used in an examination of the perceptual distortion of height among 146 college debaters. Balance theory predicted that losers would distort winners' heights upward; reinforcement theory predicted that winners would distort losers' heights upward. The results confirmed both predictions. The possibility…

  13. Perceptual and Conceptual Distortions of Implicit Hand Maps

    Directory of Open Access Journals (Sweden)

    Matthew R. Longo

    2015-12-01

    Full Text Available Recent studies have revealed that human position sense relies on a massively distorted representation of hand size and shape. By comparing the judged location of landmarks on an occluded hand, Longo and Haggard (2010 constructed implicit perceptual maps of represented hand structure, showing large underestimation of finger length and overestimation of hand width. Here, we investigated the contribution of two potential sources of distortions to such effects: perceptual distortions reflecting spatial warping of the representation of bodily tissue itself, perhaps reflecting distortions of somatotopic cortical maps, and conceptual distortions reflecting mistaken beliefs about the locations of different landmarks within the body. In Experiment 1 we compared distorted hand maps to a task in which participants explicitly judged the location of their knuckles in a hand silhouette. The results revealed the conceptual distortions are responsible for at least part of the underestimation of finger length, but cannot explain overestimation of hand width. Experiment 2 compared distortions of the participant’s own hand based on position sense with a prosthetic hand based on visual memory. Underestimation of finger length was found for both hands, providing further evidence that it reflects a conceptual distortion. In contrast, overestimation of hand width was specific to representation of the participant’s own hand, confirming it reflects a perceptual distortion. Together, these results suggest that distorted body representations do not reflect a single underlying cause. Rather, both perceptual and conceptual distortions contribute to the overall configuration of the hand representation.

  14. Microwave Service Towers

    Data.gov (United States)

    Department of Homeland Security — This file is an extract of the Universal Licensing System (ULS) licensed by the Wireless Telecommunications Bureau (WTB). It consists of Microwave Transmitters (see...

  15. Microwave Radiometer Profiler

    Data.gov (United States)

    Oak Ridge National Laboratory — The microwave radiometer profiler (MWRP) provides vertical profiles of temperature, humidity, and cloud liquid water content as a function of height or pressure at...

  16. Microwave Oven Observations.

    Science.gov (United States)

    Sumrall, William J.; Richardson, Denise; Yan, Yuan

    1998-01-01

    Explains a series of laboratory activities which employ a microwave oven to help students understand word problems that relate to states of matter, collect data, and calculate and compare electrical costs to heat energy costs. (DDR)

  17. Microwave Oven Observations.

    Science.gov (United States)

    Sumrall, William J.; Richardson, Denise; Yan, Yuan

    1998-01-01

    Explains a series of laboratory activities which employ a microwave oven to help students understand word problems that relate to states of matter, collect data, and calculate and compare electrical costs to heat energy costs. (DDR)

  18. Microwave Radiometer - high frequency

    Data.gov (United States)

    Oak Ridge National Laboratory — The Microwave Radiometer-High Frequency (MWRHF) provides time-series measurements of brightness temperatures from two channels centered at 90 and 150 GHz. These two...

  19. Note on Redshift Distortion in Fourier Space

    Institute of Scientific and Technical Information of China (English)

    Yan-Chuan Cai; Jun Pan

    2007-01-01

    We explore features of redshift distortion in Fourier analysis of N-body simulations.The phases of the Fourier modes of dark matter density fluctuation are generally shifted by the peculiar motion along the line of sight, the induced phase shift is stochastic and has a probability distribution function (PDF) that is symmetric about the peak at zero shift and whose exact shape depends on the wave vector, except on very large scales where phases are invariant by linear perturbation theory. Analysis of the phase shifts motivates our phenomenological models for the bispectrum in redshift space. Comparison with simulations shows that our toy models are very successful in modeling bispectrum of equilateral and isosceles triangles at large scales. In the second part we compare the monopole of the power spectrum and bispectrum in the radial and plane-parallel distortion to test the plane-parallel approximation.We confirm the results of Scoccimarro that difference of power spectrum is at the level of 10%, and, in the reduced bispectrum, the difference is as small as a few percent. However, on the plane perpendicular to the line of sight of kz = 0, the difference in power spectrum between the radial and plane-parallel approximation can be more than ~ 10%, and even worse on very small scales. Such difference is prominent for bispectrum, especially for configurations of tilted triangles. Non-Gaussian signals under the radial distortion on small scales are systematically biased downside than are in the plane-parallel approximation, with amplitudes depending on the opening angle of the sample point to the observer. This observation gives warning to the practice of using the power spectrum and bispectrum measured on the kz = 0 plane as estimates of the real space statistics.

  20. Filter based phase distortions in extracellular spikes.

    Science.gov (United States)

    Yael, Dorin; Bar-Gad, Izhar

    2017-01-01

    Extracellular recordings are the primary tool for extracting neuronal spike trains in-vivo. One of the crucial pre-processing stages of this signal is the high-pass filtration used to isolate neuronal spiking activity. Filters are characterized by changes in the magnitude and phase of different frequencies. While filters are typically chosen for their effect on magnitudes, little attention has been paid to the impact of these filters on the phase of each frequency. In this study we show that in the case of nonlinear phase shifts generated by most online and offline filters, the signal is severely distorted, resulting in an alteration of the spike waveform. This distortion leads to a shape that deviates from the original waveform as a function of its constituent frequencies, and a dramatic reduction in the SNR of the waveform that disrupts spike detectability. Currently, the vast majority of articles utilizing extracellular data are subject to these distortions since most commercial and academic hardware and software utilize nonlinear phase filters. We show that this severe problem can be avoided by recording wide-band signals followed by zero phase filtering, or alternatively corrected by reversed filtering of a narrow-band filtered, and in some cases even segmented signals. Implementation of either zero phase filtering or phase correction of the nonlinear phase filtering reproduces the original spike waveforms and increases the spike detection rates while reducing the number of false negative and positive errors. This process, in turn, helps eliminate subsequent errors in downstream analyses and misinterpretations of the results.

  1. Filter based phase distortions in extracellular spikes

    Science.gov (United States)

    Yael, Dorin

    2017-01-01

    Extracellular recordings are the primary tool for extracting neuronal spike trains in-vivo. One of the crucial pre-processing stages of this signal is the high-pass filtration used to isolate neuronal spiking activity. Filters are characterized by changes in the magnitude and phase of different frequencies. While filters are typically chosen for their effect on magnitudes, little attention has been paid to the impact of these filters on the phase of each frequency. In this study we show that in the case of nonlinear phase shifts generated by most online and offline filters, the signal is severely distorted, resulting in an alteration of the spike waveform. This distortion leads to a shape that deviates from the original waveform as a function of its constituent frequencies, and a dramatic reduction in the SNR of the waveform that disrupts spike detectability. Currently, the vast majority of articles utilizing extracellular data are subject to these distortions since most commercial and academic hardware and software utilize nonlinear phase filters. We show that this severe problem can be avoided by recording wide-band signals followed by zero phase filtering, or alternatively corrected by reversed filtering of a narrow-band filtered, and in some cases even segmented signals. Implementation of either zero phase filtering or phase correction of the nonlinear phase filtering reproduces the original spike waveforms and increases the spike detection rates while reducing the number of false negative and positive errors. This process, in turn, helps eliminate subsequent errors in downstream analyses and misinterpretations of the results. PMID:28358895

  2. Bounded distortion homeomorphisms on ultrametric spaces

    CERN Document Server

    Hughes, Bruce; Morón, Manuel A

    2010-01-01

    It is well-known that quasi-isometries between R-trees induce power quasi-symmetric homeomorphisms between their ultrametric end spaces. This paper investigates power quasi-symmetric homeomorphisms between bounded, complete, uniformly perfect, ultrametric spaces (i.e., those ultrametric spaces arising up to similarity as the end spaces of bushy trees). A bounded distortion property is found that characterizes power quasi-symmetric homeomorphisms between such ultrametric spaces that are also pseudo-doubling. Moreover, examples are given showing the extent to which the power quasi-symmetry of homeomorphisms is not captured by the quasiconformal and bi-H\\"older conditions for this class of ultrametric spaces.

  3. Towards distortion-free robust image authentication

    Energy Technology Data Exchange (ETDEWEB)

    Coltuc, D [EE Department, Valahia University Targoviste (Romania)

    2007-07-15

    This paper investigates a general framework for distortion-free robust image authentication by multiple marking. First, by robust watermarking a subsampled version of image edges is embedded. Then, by reversible watermarking the information needed to recover the original image is inserted, too. The hiding capacity of the reversible watermarking is the essential requirement for this approach. Thus in case of no attacks not only image is authenticated but also the original is exactly recovered. In case of attacks, reversibility is lost, but image can still be authenticated. Preliminary results providing very good robustness against JPEG compression are presented.

  4. The Distorted Wheeler-DeWitt Equation

    CERN Document Server

    Garattini, Remo

    2015-01-01

    The Wheeler-DeWitt Equation represents a tool to study Quantum Gravity and Quantum Cosmology. Its solution in a very general context is, of course, impossible. To this purpose we consider some distortions of General Relativity like Gravity's Rainbow, Varying Speed of Light Cosmology, Generalized Uncertainty Principle deformations and Ho\\v{r}ava-Lifshitz gravity which could allow the calculation of some observables like the cosmological constant. For simplicity we consider only the Mini-Superspace approach related to a Friedmann-Lema\\^itre-Robertson-Walker space-time.

  5. Microwave workshop for Windows

    Directory of Open Access Journals (Sweden)

    Colin White

    1995-12-01

    Full Text Available A suite of three programs has been developed to support the teaching of microwave theory and design. A secondary function of the package is to support microwave engineers by providing a library of utilities to assist their design function. All three programs were written in Visual Basic and are aimed at supporting both tutor-directed and student-centred learning methodologies. The development team consisted of three final-year degree students.

  6. Microwave system engineering principles

    CERN Document Server

    Raff, Samuel J

    1977-01-01

    Microwave System Engineering Principles focuses on the calculus, differential equations, and transforms of microwave systems. This book discusses the basic nature and principles that can be derived from thermal noise; statistical concepts and binomial distribution; incoherent signal processing; basic properties of antennas; and beam widths and useful approximations. The fundamentals of propagation; LaPlace's Equation and Transmission Line (TEM) waves; interfaces between homogeneous media; modulation, bandwidth, and noise; and communications satellites are also deliberated in this text. This bo

  7. Prediction of Part Distortion in Die Casting

    Energy Technology Data Exchange (ETDEWEB)

    R. Allen Miller

    2005-03-30

    The die casting process is one of the net shape manufacturing techniques and is widely used to produce high production castings with tight tolerances for many industries. An understanding of the stress distribution and the deformation pattern of parts produced by die casting will result in less deviation from the part design specification, a better die design and eventually more productivity and cost savings. This report presents methods that can be used to simulate the die casting process in order to predict the deformation and stresses in the produced part and assesses the degree to which distortion modeling is practical for die casting at the current time. A coupled thermal-mechanical finite elements model was used to simulate the die casting process. The simulation models the effect of thermal and mechanical interaction between the casting and the die. It also includes the temperature dependant material properties of the casting. Based on a designed experiment, a sensitivity analysis was conducted on the model to investigate the effect of key factors. These factors include the casting material model, material properties and thermal interaction between casting and dies. To verify the casting distortion predictions, it was compared against the measured dimensions of produced parts. The comparison included dimensions along and across the parting plane and the flatness of one surface.

  8. Insider censoring: Distortion of data with nondetects

    Science.gov (United States)

    Helsel, D.R.

    2005-01-01

    Environmental data often include low-level concentrations below reporting limits. These data may be reported as "distorting the shape of the data distribution. This results in inaccurate estimates of summary statistics and regression coefficients, distorts evaluations of whether data follow a normal distribution, and introduces inaccuracies into risk assessments and models. Insider censoring occurs when data measured as below the detection limit (

  9. A Minimal Solution to Radial Distortion Autocalibration.

    Science.gov (United States)

    Kukelova, Zuzana; Pajdla, Tomas

    2011-12-01

    Simultaneous estimation of radial distortion, epipolar geometry, and relative camera pose can be formulated as a minimal problem and solved from a minimal number of image points. Finding the solution to this problem leads to solving a system of algebraic equations. In this paper, we provide two different solutions to the problem of estimating radial distortion and epipolar geometry from eight point correspondences in two images. Unlike previous algorithms which were able to solve the problem from nine correspondences only, we enforce the determinant of the fundamental matrix be zero. This leads to a system of eight quadratic and one cubic equation in nine variables. We first simplify this system by eliminating six of these variables and then solve the system by two alternative techniques. The first one is based on the Gröbner basis method and the second one on the polynomial eigenvalue computation. We demonstrate that our solutions are efficient, robust, and practical by experiments on synthetic and real data.

  10. Reducing Field Distortion in Magnetic Resonance Imaging

    Science.gov (United States)

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

    2010-01-01

    A concept for a magnetic resonance imaging (MRI) system that would utilize a relatively weak magnetic field provides for several design features that differ significantly from the corresponding features of conventional MRI systems. Notable among these features are a magnetic-field configuration that reduces (relative to the conventional configuration) distortion and blurring of the image, the use of a superconducting quantum interference device (SQUID) magnetometer as the detector, and an imaging procedure suited for the unconventional field configuration and sensor. In a typical application of MRI, a radio-frequency pulse is used to excite precession of the magnetic moments of protons in an applied magnetic field, and the decaying precession is detected for a short time following the pulse. The precession occurs at a resonance frequency proportional to the strengths of the magnetic field and the proton magnetic moment. The magnetic field is configured to vary with position in a known way; hence, by virtue of the aforesaid proportionality, the resonance frequency varies with position in a known way. In other words, position is encoded as resonance frequency. MRI using magnetic fields weaker than those of conventional MRI offers several advantages, including cheaper and smaller equipment, greater compatibility with metallic objects, and higher image quality because of low susceptibility distortion and enhanced spin-lattice-relaxation- time contrast. SQUID MRI is being developed into a practical MRI method for applied magnetic flux densities of the order of only 100 T

  11. Diborane release and structure distortion in borohydrides.

    Science.gov (United States)

    Callini, Elsa; Borgschulte, Andreas; Ramirez-Cuesta, Anibal Javier; Züttel, Andreas

    2013-01-21

    Hydrogen desorption from borohydrides is often accompanied by the release of diborane. The amount of diborane released as a byproduct during the decomposition of borohydrides scales inversely with the borohydride stability, which in turn depends on the electronegativity of the corresponding cation. We present a model based on the difference between the symmetric and asymmetric assembly of B(2)H(6) units at the surface. The origin of this reaction is the degree of distortion of the BH(4)(-) anions in the bulk, hitherto depending on the degree of ionization of the cation. A practical measure of the distortion is the range in which the stretching vibration modes appear, which is the difference in the energy of the stretching vibrations of hydrogen atoms with maximum different bonding lengths (Badger's rule). We propose from this relation that the diborane released from the surface of the relatively unstable LiZn(2)(BH(4))(5) is formed from a recombination of BH(2)(δ+) and BH(4)(δ-) units. Ultra high vacuum mass spectroscopy measurements support the presented model and clarify the decomposition of stable borohydrides, such as LiBH(4). The sublimation of borohydrides in UHV competes with their decomposition.

  12. Flow distortion on boom mounted cup anemometers

    Energy Technology Data Exchange (ETDEWEB)

    Lindeloew-Marsden, P.; Pedersen, Troels F.; Gottschall, J.; Vesth, A.; Paulsen, R.W.U.; Courtney, M.S.

    2010-08-15

    In this report we investigate on wind direction dependent errors in the measurement of the horizontal wind speed by boom mounted cup anemometers. The boom mounting on the studied lattice tower is performed according to IEC standard design rules, yet, larger deviations than predicted by flow models are observed. The errors on the measurements are likely caused by an underestimation of the flow distortions around the tower. In this paper an experimental method for deriving a correction formula and an in-field calibration is suggested. The method is based on measurements with two cup anemometers mounted with booms at the same height but pointing in 60 deg. different directions. In the examined case of a 1.9 m wide equilateral triangular lattice tower with booms protruding 4.1 m at 80 m height the measurement errors are observed to reach up to +- 2 %. Errors of this magnitude are severely problematic in the measurement of wind turbine power performance, wind resource assessment and for providing purposeful in-field comparisons between different sensors, e.g. lidar anemometers. With the proposed method, direction dependent errors can be extracted and the mast flow distortion effect on the wind measurements corrected to an uncertainty estimated to better than 0.5%. This level of uncertainty is probably acceptable for the above mentioned applications. (author)

  13. A comparison of three dimensional change in maxillary complete dentures between conventional heat polymerizing and microwave polymerizing techniques

    Directory of Open Access Journals (Sweden)

    Shinsuke Sadamori

    2007-03-01

    Full Text Available The purpose of this study was to measure and compare two different polymerizing processes, heat polymerizing (HP and microwave polymerizing (MP, on the three dimensional changes in the fitting surface and artificial teeth of maxillary complete dentures. A threedimensional coordinate measurement system was used to record distortion of the specimens. The distortion of the fitting surface was measured from the reference plane on the fitting side from which a coordinate system was set, and the movement of the artificial teeth and the distortion of the polished surface was measured from the reference plane of the artificial tooth side, from which a coordinate system was set. It was clearly showed that various distortions of denture specimens after polymerization process can be measured with this three-coordinate measuring machine. The study showed that the overall distortion of the fitting surface in HP specimens was shown to be larger than in MP ones.

  14. Beyond the Boost: Measuring the intrinsic dipole of the CMB using the spectral distortions of the monopole and quadrupole

    CERN Document Server

    Yasini, Siavash

    2016-01-01

    We present a method aimed at separating the motion-induced dipole of the cosmic microwave background (CMB) from the intrinsic, primordial dipole component. We show that in a moving frame, the leakage of an intrinsic dipole moment into the CMB monopole and quadrupole induces spectral distortions with distinct frequency functions that respectively peak at 266 GHz and 310 GHz at $\\sim 10$nK level. The leakage into the quadrupole moment also induces a geometrical distortion to the spatial morphology of this mode. The combination of these effects can be used to lift the degeneracy between the motion-induced dipole and any intrinsic dipole that the CMB might possess. The leakage of an intrinsic dipole of order $\\sim 10^{-5}$ into the monopole and quadrupole moments will be detectable by a PIXIE--like experiment at $\\sim 6\\sigma$ at the peak frequency.

  15. Design of the new rigid endoscope distortion measurement system

    Science.gov (United States)

    Zhai, Xiaohao; Liu, Xiaohua; Liu, Ming; Hui, Mei; Dong, Liquan; Zhao, Yuejin; Wang, Yakun; Li, Yonghui; Zhou, Peng

    2015-08-01

    Endoscopic imaging quality affects industrial safety and medical security. Rigid endoscope distortion is of great signification as one of optical parameters to evaluate the imaging quality. This paper introduces a new method of rigid endoscope distortion measurement, which is different from the common methods with low accuracy and fussy operation. It contains a Liquid Crystal Display (LCD) to display the target, a CCD to obtain the images with distortion, and a computer to process the images. The LCD is employed instead of common white screen. The autonomous control system of LCD makes it showing the test target designed for distortion, and its parameter is known. LCD control system can change the test target to satisfy the different demand for accuracy, which avoids replacing target frequently. The test system also contains a CCD to acquire images in the exit pupil position of rigid endoscope. Rigid endoscope distortion is regarded as centrosymmetric, and the MATLAB software automatically measures it by processing the images from CCD. The MATLAB software compares target images with that without distortion on LCD and calculates the results. Relative distortion is obtained at different field of view (FOV) radius. The computer plots the curve of relative distortion, abscissa means radius of FOV, ordinate means relative distortion. The industry standard shows that, the distortion at 70% field of view is pointed on the curve, which can be taken as an evaluation standard. This new measuring method achieves advantages of high precision, high degree of intelligence, excellent repeatability and gets calculation results quickly.

  16. JET ENGINE INLET DISTORTION SCREEN AND DESCRIPTOR EVALUATION

    Directory of Open Access Journals (Sweden)

    Jiří Pečinka

    2017-02-01

    Full Text Available Total pressure distortion is one of the three basic flow distortions (total pressure, total temperature and swirl distortion that might appear at the inlet of a gas turbine engine (GTE during operation. Different numerical parameters are used for assessing the total pressure distortion intensity and extent. These summary descriptors are based on the distribution of total pressure in the aerodynamic interface plane. There are two descriptors largely spread around the world, however, three or four others are still in use and can be found in current references. The staff at the University of Defence decided to compare the most common descriptors using basic flow distortion patterns in order to select the most appropriate descriptor for future department research. The most common descriptors were identified based on their prevalence in widely accessible publications. The construction and use of these descriptors are reviewed in the paper. Subsequently, they are applied to radial, angular, and combined distortion patterns of different intensities and with varied mass flow rates. The tests were performed on a specially designed test bench using an electrically driven standalone industrial centrifugal compressor, sucking air through the inlet of a TJ100 small turbojet engine. Distortion screens were placed into the inlet channel to create the desired total pressure distortions. Of the three basic distortions, only the total pressure distortion descriptors were evaluated. However, both total and static pressures were collected using a multi probe rotational measurement system.

  17. Microwave spectrum and molecular constants of indole

    Science.gov (United States)

    Nesvadba, Radim; Studecký, Tomáš; Uhlíková, Tereza; Urban, Štěpán

    2017-09-01

    Every single person has a certain characteristic group of scent molecules. The microwave spectra of the organic compounds of scent could be useful for the identification of people, but a database of spectra of scent molecules needs to be created first. The spectrum of indole, that is among the human scent molecules, was measured in the frequency range of 7.5-19 GHz under the conditions of supersonic expansion in a pulse emission Fourier Transform Microwave Spectrometer (FTMW) with a Fabry-Perot resonator. The high resolution of the spectrometer enables the detection of rotational transitions with hyperfine splitting. A total of 37 new rotational transitions were measured and analyzed using the PGOPHER software to derive the rotational and centrifugal distortion constants, as well as the 14N nuclear quadrupole coupling constants. The molecular constants were determined with approximately two orders of magnitude greater accuracy as compared with some earlier studies of indole. The obtained data and constants of indole are the first step towards the development of a database of the human scent molecules.

  18. Anomalous Microwave Emission

    CERN Document Server

    Kogut, A J

    1999-01-01

    Improved knowledge of diffuse Galactic emission is important to maximize the scientific return from scheduled CMB anisotropy missions. Cross-correlation of microwave maps with maps of the far-IR dust continuum show a ubiquitous microwave emission component whose spatial distribution is traced by far-IR dust emission. The spectral index of this emission, beta_{radio} = -2.2 (+0.5 -0.7) is suggestive of free-free emission but does not preclude other candidates. Comparison of H-alpha and microwave results show that both data sets have positive correlations with the far-IR dust emission. Microwave data, however, are consistently brighter than can be explained solely from free-free emission traced by H-alpha. This ``anomalous'' microwave emission can be explained as electric dipole radiation from small spinning dust grains. The anomalous component at 53 GHz is 2.5 times as bright as the free-free emission traced by H-alpha, providing an approximate normalization for models with significant spinning dust emission.

  19. Microwave engineering concepts and fundamentals

    CERN Document Server

    Khan, Ahmad Shahid

    2014-01-01

    Detailing the active and passive aspects of microwaves, Microwave Engineering: Concepts and Fundamentals covers everything from wave propagation to reflection and refraction, guided waves, and transmission lines, providing a comprehensive understanding of the underlying principles at the core of microwave engineering. This encyclopedic text not only encompasses nearly all facets of microwave engineering, but also gives all topics—including microwave generation, measurement, and processing—equal emphasis. Packed with illustrations to aid in comprehension, the book: •Describes the mathematical theory of waveguides and ferrite devices, devoting an entire chapter to the Smith chart and its applications •Discusses different types of microwave components, antennas, tubes, transistors, diodes, and parametric devices •Examines various attributes of cavity resonators, semiconductor and RF/microwave devices, and microwave integrated circuits •Addresses scattering parameters and their properties, as well a...

  20. Wave front distortion based fluid flow imaging

    Science.gov (United States)

    Iffa, Emishaw; Heidrich, Wolfgang

    2013-03-01

    In this paper, a transparent flow surface reconstruction based on wave front distortion is investigated. A camera lens is used to focus the image formed by the micro-lens array to the camera imaging plane. The irradiance of the captured image is transformed to frequency spectrum and then the x and y spatial components are separated. A rigid spatial translation followed by low pass filtering yields a single frequency component of the image intensity. Index of refraction is estimated from the inverse Fourier transform of the spatial frequency spectrum of the irradiance. The proposed method is evaluated with synthetic data of a randomly generated index of refraction value and used to visualize a fuel injection volumetric data.

  1. Distorted Coulomb field of the scattered electron

    CERN Document Server

    Thomsen, H D; Andersen, K K; Lund, M D; Knudsen, H; Uggerhøj, E; Uggerhøj1, U I; Sona, P; Mangiarotti, A; Ketel, T J; Dizdar, A; Ballestrero, S; Connell, S H

    2010-01-01

    Experimental results for the radiation emission from ultrarelativistic electrons in targets of 0.03%–5% radiation length is presented. For the thinnest targets, the radiation emission is in accordance with the Bethe-Heitler formulation of bremsstrahlung, the target acting as a single scatterer. In this regime, the radiation intensity is proportional to the thickness. As the thickness increases, the distorted Coulomb field of the electron that is the result of the first scattering events, leads to a suppressed radiation emission per interaction, upon subsequent scattering events. In that case, the radiation intensity becomes proportional to a logarithmic function of the thickness, due to the suppression. Eventually, once the target becomes sufficiently thick, the entire radiation process becomes influenced by multiple scattering and the radiation intensity is again proportional to the thickness, but with a different constant of proportionality. The observed logarithmic thickness dependence of radiation inten...

  2. Distribution function approach to redshift space distortions

    CERN Document Server

    Seljak, Uros

    2011-01-01

    We develop a phase space distribution function approach to redshift space distortions (RSD), in which the redshift space density can be written as a sum over velocity moments of the distribution function. These moments are density weighted and their lowest orders are density, momentum density, and stress energy density. The series expansion is convergent on large scales. We perform an expansion of these velocity moments into helicity modes, which are eigenmodes under rotation around the axis of Fourier mode direction, generalizing the scalar, vector, tensor decomposition of perturbations to an arbitrary order. We show that only equal helicity moments correlate and derive the angular dependence of the individual contributions to the redshift space power spectrum in terms of angle mu between wave vector and line of sight. We show that the dominant term of mu^2 dependence on large scales is the cross-correlation between the density and scalar part of momentum density, which can be related to the time derivative ...

  3. Power Factor Correction to Mitigate Harmonic Distortion

    Science.gov (United States)

    Kochetkov, Gary

    Many direct current (DC) devices must receive their power from the alternating current (AC) grid. Rectifiers use diodes to create DC for these devices. Due to diodes' non-linear nature however, harmonics are created and these travel back into the grid. A significant presence of harmonics causes component heating and possible malfunction. A harmonic mitigation procedure is needed. With the correct usage of transistors, the current drawn by a rectifier can be manipulated to remove almost all harmonics. This process is called power factor correction (PFC), and formally acts to reduce the total harmonic distortion (THD) of the current. To investigate this, a three phase active rectifier was computer simulated and a controller was designed to provide switching signals for the transistors. Finally, the device was constructed in the laboratory to drive a DC motor, verifying its operating principle outside of the idealities of simulation.

  4. Use of distorted waves in the theory of inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Picklesimer, A.; Tandy, P.C.; Thaler, R.M.

    1982-03-01

    A distorted wave description of inelastic scattering of nucleons from nuclei is formulated so that the microscopic content of the various ingredients can be made explicit. Special care is taken to ensure that physical processes are not overcounted as a consequence of the use of distorted waves in both the initial and final channels. Two attitudes to applications of the theory are taken. In the first, it is assumed that phenomenological distorted waves are employed and attention is focused upon the microscopic transition potential and the final distorted wave. Theoretically based recommendations for practical calculations of both these quantities are given. Secondly, we present a completely microscopic treatment wherein the truncations of the microscopic distorting potentials and the transition potential, at the single scattering level, are consistent with the underlying theoretical framework which links them. Our approach is designed to embody the distorted wave impulse approximation as a suitable lowest order result. Again, recommendations for practical calculations are given.

  5. Study Of Gear Teeth Distortions Due To Heat Treatment

    Directory of Open Access Journals (Sweden)

    V. Khade

    2015-02-01

    Full Text Available Abstract The work aims to study the distortion occurred due to heat treatment on the Gear teeth. The paper studies various causes of distortion control techniques to eliminate distortion which includes changes in design selection of material heat treatment process mainly due to quenching that includes cooling rates quenching mediums fixtures. An experimental study and results conducted for the effects of the distortion on the Gear teeth and to reduce the distortion with certain changes design modification resulting in shape amp size changes phase changes changes in hardness microstructure and residual stresses. It is observed that adequate velocity of quench oil around the component to be heat treated ensures uniform amp desired cooling rate as per heat treatment cycle. Modification in design of baffles achieved the adequate velocity and minimization of distortion. Also Fixtures for holding finished parts or assemblies during heat treatment may be either support or restraint type to control dimensional relations during aging.

  6. Global and Local Distortion Inference During Embedded Zerotree Wavelet Decompression

    Science.gov (United States)

    Huber, A. Kris; Budge, Scott E.

    1996-01-01

    This paper presents algorithms for inferring global and spatially local estimates of the squared-error distortion measures for the Embedded Zerotree Wavelet (EZW) image compression algorithm. All distortion estimates are obtained at the decoder without significantly compromising EZW's rate-distortion performance. Two methods are given for propagating distortion estimates from the wavelet domain to the spatial domain, thus giving individual estimates of distortion for each pixel of the decompressed image. These local distortion estimates seem to provide only slight improvement in the statistical characterization of EZW compression error relative to the global measure, unless actual squared errors are propagated. However, they provide qualitative information about the asymptotic nature of the error that may be helpful in wavelet filter selection for low bit rate applications.

  7. Influence of initial state distortion in ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ciappina, M F [CONICET and Departamento de FIsica, Universidad Nacional del Sur, 8000 BahIa Blanca (Argentina); Cravero, W R [CONICET and Departamento de FIsica, Universidad Nacional del Sur, 8000 BahIa Blanca (Argentina); Garibotti, C R [CONICET and Division Colisiones Atomicas, Centro Atomico Bariloche, 8400 Bariloche (Argentina)

    2004-05-28

    We have studied the influence of initial state distortion in a single ionization by ion impact. We have taken a continuum distorted wave type distortion and by taking up to the first order in its asymptotic series expansion we build an eikonal-spherical distortion. In this way the influence of each term in the transition amplitude can be stated. This approximation can be considered an intermediate one between the eikonal initial state and the continuum distorted wave approaches for initial state distortion. We have computed doubly differential cross sections for helium ionization by protons and highly charged ions at high and intermediate impact energy. We have also discussed the contribution of the different terms in electron energy spectra, specially in the vicinity of ECC peak. Very good agreement is found with the available experimental data.

  8. Distortion of ceramometal fixed partial dentures during the firing cycle.

    Science.gov (United States)

    Bridger, D V; Nicholls, J I

    1981-05-01

    1. Distortion does occur in the body of curved, long-span fixed partial denture frameworks during the porcelain firing cycle. 2. This distortion is a result of changes in the metal as well as the contraction of fired porcelain. 3. The greatest distortional changes occur during the degassing stage and the final glaze stage of the porcelain firing cycle. 4. Distortion incurred by the application and firing of the porcelain is reversible. When the porcelain is chemically removed from the framework, there is an elastic rebound. 5. Distortion is clinically important in that it may lead to detectable marginal openings. 6. The distortion pattern observed in the curved fixed partial denture is a closing of the posterior or lingual dimensions and labial movement in the anterior dimension. This indicates the effect of the contracting porcelain on the metal framework.

  9. A corrected method of distorted printed circuit board image

    Institute of Scientific and Technical Information of China (English)

    Qiao Nao-Sheng; Ye Yu-Tang; Huang Yong-Lin

    2011-01-01

    This paper proposes a corrected method of distorted image based on adaptive control. First, the adaptive control relationship of pixel point positions between distorted image and its corrected image is given by using polynomial fitting,thus control point pairs between the distorted image and its corrected image are found. Secondly, the value of both image distortion centre and polynomial coefficient is obtained with least square method, thus the relationship of each control point pairs is deduced. In the course of distortion image processing, the gray value of the corrected image is changed into integer with bilinear interpolation. Finally, the experiments are performed to correct two distorted printed circuit board images. The results are perfect and the mean square errors of residual error are tiny.

  10. High power microwaves

    CERN Document Server

    Benford, James; Schamiloglu, Edl

    2016-01-01

    Following in the footsteps of its popular predecessors, High Power Microwaves, Third Edition continues to provide a wide-angle, integrated view of the field of high power microwaves (HPMs). This third edition includes significant updates in every chapter as well as a new chapter on beamless systems that covers nonlinear transmission lines. Written by an experimentalist, a theorist, and an applied theorist, respectively, the book offers complementary perspectives on different source types. The authors address: * How HPM relates historically and technically to the conventional microwave field * The possible applications for HPM and the key criteria that HPM devices have to meet in order to be applied * How high power sources work, including their performance capabilities and limitations * The broad fundamental issues to be addressed in the future for a wide variety of source types The book is accessible to several audiences. Researchers currently in the field can widen their understanding of HPM. Present or pot...

  11. Microwave-assisted Chemical Transformations

    Science.gov (United States)

    In recent years, there has been a considerable interest in developing sustainable chemistries utilizing green chemistry principles. Since the first published report in 1986 by Gedye and Giguere on microwave assisted synthesis in household microwave ovens, the use of microwaves as...

  12. Physics of the Microwave Oven

    Science.gov (United States)

    Vollmer, Michael

    2004-01-01

    This is the first of two articles about the physics of microwave ovens. This article deals with the generation of microwaves in the oven and includes the operation of the magnetrons, waveguides and standing waves in resonant cavities. It then considers the absorption of microwaves by foods, discussing the dielectric relaxation of water,…

  13. Physics of the Microwave Oven

    Science.gov (United States)

    Vollmer, Michael

    2004-01-01

    This is the first of two articles about the physics of microwave ovens. This article deals with the generation of microwaves in the oven and includes the operation of the magnetrons, waveguides and standing waves in resonant cavities. It then considers the absorption of microwaves by foods, discussing the dielectric relaxation of water,…

  14. A new interpretation of distortion artifacts in sweep measurements

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Jacobsen, Finn

    2011-01-01

    The characterization of acoustical spaces by means of impulse response measurements is often biased by the nonlinear behavior of the loudspeaker used to excite the system under test. In this context the distortion immunity provided by the sweep technique has been investigated. The results show th...... that the sweep method can reject a significant amount of distortion artifacts but, in contrast to what is claimed in the literature, it cannot exclude all distortion artifacts from the causal part of the estimated impulse response....

  15. A microwave powered sensor assembly for microwave ovens

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a microwave powered sensor assembly for micro- wave ovens. The microwave powered sensor assembly comprises a microwave antenna for generating an RF antenna signal in response to microwave radiation at a predetermined excitation frequency. A dc power supply circuit...... of the microwave powered sensor assembly is operatively coupled to the RF antenna signal for extracting energy from the RF antenna signal and produce a power supply voltage. A sensor is connected to the power supply voltage and configured to measure a physical or chemical property of a food item under heating...

  16. Microwave Frequency Polarizers

    Science.gov (United States)

    Ha, Vien The; Mirel, Paul; Kogut, Alan J.

    2013-01-01

    This article describes the fabrication and analysis of microwave frequency polarizing grids. The grids are designed to measure polarization from the cosmic microwave background. It is effective in the range of 500 to 1500 micron wavelength. It is cryogenic compatible and highly robust to high load impacts. Each grid is fabricated using an array of different assembly processes which vary in the types of tension mechanisms to the shape and size of the grids. We provide a comprehensive study on the analysis of the grids' wire heights, diameters, and spacing.

  17. Microwave Discharge Ion Sources

    CERN Document Server

    Celona, L

    2013-01-01

    This chapter describes the basic principles, design features and characteristics of microwave discharge ion sources. A suitable source for the production of intense beams for high-power accelerators must satisfy the requirements of high brightness, stability and reliability. The 2.45 GHz off-resonance microwave discharge sources are ideal devices to generate the required beams, as they produce multimilliampere beams of protons, deuterons and singly charged ions. A description of different technical designs will be given, analysing their performance, with particular attention being paid to the quality of the beam, especially in terms of its emittance.

  18. Fundamentals of microwave photonics

    CERN Document Server

    Urick, V J; McKinney , Jason D

    2015-01-01

    A comprehensive resource to designing andconstructing analog photonic links capable of high RFperformanceFundamentals of Microwave Photonics provides acomprehensive description of analog optical links from basicprinciples to applications.  The book is organized into fourparts. The first begins with a historical perspective of microwavephotonics, listing the advantages of fiber optic links anddelineating analog vs. digital links. The second section coversbasic principles associated with microwave photonics in both the RFand optical domains.  The third focuses on analog modulationformats-starti

  19. Microwave circulator design

    CERN Document Server

    Linkhart, Douglas K

    2014-01-01

    Circulator design has advanced significantly since the first edition of this book was published 25 years ago. The objective of this second edition is to present theory, information, and design procedures that will enable microwave engineers and technicians to design and build circulators successfully. This resource contains a discussion of the various units used in the circulator design computations, as well as covers the theory of operation. This book presents numerous applications, giving microwave engineers new ideas about how to solve problems using circulators. Design examples are provided, which demonstrate how to apply the information to real-world design tasks.

  20. Microwave Assisted Drug Delivery

    DEFF Research Database (Denmark)

    Jónasson, Sævar Þór; Zhurbenko, Vitaliy; Johansen, Tom Keinicke

    2014-01-01

    In this work, the microwave radiation is adopted for remote activation of pharmaceutical drug capsules inside the human body in order to release drugs at a pre-determined time and location. An array of controllable transmitting sources is used to produce a constructive interference at a certain...... focus point inside the body, where the drugs are then released from the specially designed capsules. An experimental setup for microwave activation has been developed and tested on a body phantom that emulates the human torso. A design of sensitive receiving structures for integration with a drug...

  1. Microwave Assisted Drug Delivery

    DEFF Research Database (Denmark)

    Jónasson, Sævar Þór; Zhurbenko, Vitaliy; Johansen, Tom Keinicke

    2014-01-01

    In this work, the microwave radiation is adopted for remote activation of pharmaceutical drug capsules inside the human body in order to release drugs at a pre-determined time and location. An array of controllable transmitting sources is used to produce a constructive interference at a certain...... focus point inside the body, where the drugs are then released from the specially designed capsules. An experimental setup for microwave activation has been developed and tested on a body phantom that emulates the human torso. A design of sensitive receiving structures for integration with a drug...

  2. EDITORIAL: Microwave Moisture Measurements

    Science.gov (United States)

    Kaatze, Udo; Kupfer, Klaus; Hübner, Christof

    2007-04-01

    Microwave moisture measurements refer to a methodology by which the water content of materials is non-invasively determined using electromagnetic fields of radio and microwave frequencies. Being the omnipresent liquid on our planet, water occurs as a component in most materials and often exercises a significant influence on their properties. Precise measurements of the water content are thus extremely useful in pure sciences, particularly in biochemistry and biophysics. They are likewise important in many agricultural, technical and industrial fields. Applications are broad and diverse, and include the quality assessment of foodstuffs, the determination of water content in paper, cardboard and textile production, the monitoring of moisture in sands, gravels, soils and constructions, as well as the measurement of water admixtures to coal and crude oil in reservoirs and in pipelines. Microwave moisture measurements and evaluations require insights in various disciplines, such as materials science, dielectrics, the physical chemistry of water, electrodynamics and microwave techniques. The cooperation of experts from the different fields of science is thus necessary for the efficient development of this complex discipline. In order to advance cooperation the Workshop on Electromagnetic Wave Interaction with Water and Moist Substances was held in 1993 in Atlanta. It initiated a series of international conferences, of which the last one was held in 2005 in Weimar. The meeting brought together 130 scientists and engineers from all over the world. This special issue presents a collection of some selected papers that were given at the event. The papers cover most topics of the conference, featuring dielectric properties of aqueous materials, electromagnetic wave interactions, measurement methods and sensors, and various applications. The special issue is dedicated to Dr Andrzej W Kraszewski, who died in July 2006 after a distinguished career of 48 years in the research of

  3. Spectral Distortion in Lossy Compression of Hyperspectral Data

    Directory of Open Access Journals (Sweden)

    Bruno Aiazzi

    2012-01-01

    Full Text Available Distortion allocation varying with wavelength in lossy compression of hyperspectral imagery is investigated, with the aim of minimizing the spectral distortion between original and decompressed data. The absolute angular error, or spectral angle mapper (SAM, is used to quantify spectral distortion, while radiometric distortions are measured by maximum absolute deviation (MAD for near-lossless methods, for example, differential pulse code modulation (DPCM, or mean-squared error (MSE for lossy methods, for example, spectral decorrelation followed by JPEG 2000. Two strategies of interband distortion allocation are compared: given a target average bit rate, distortion may be set to be constant with wavelength. Otherwise, it may be allocated proportionally to the noise level of each band, according to the virtually lossless protocol. Comparisons with the uncompressed originals show that the average SAM of radiance spectra is minimized by constant distortion allocation to radiance data. However, variable distortion allocation according to the virtually lossless protocol yields significantly lower SAM in case of reflectance spectra obtained from compressed radiance data, if compared with the constant distortion allocation at the same compression ratio.

  4. High-order harmonic generation from eld-distorted orbitals

    DEFF Research Database (Denmark)

    Spiewanowski, Maciek; Etches, Adam; Madsen, Lars Bojer

    We investigate the eect on high-order harmonic generation of the distortion of molecular orbitals by the driving laser eld. Calculations for high-order harmonic generation including orbital distortion are performed for N2 (high polarizability). Our results allow us to suggest that field-distortio......We investigate the eect on high-order harmonic generation of the distortion of molecular orbitals by the driving laser eld. Calculations for high-order harmonic generation including orbital distortion are performed for N2 (high polarizability). Our results allow us to suggest that field...

  5. Pulse-distortion in a quantum-dot optical amplifier

    DEFF Research Database (Denmark)

    Romstad, Francis Pascal; Borri, Paola; Mørk, Jesper;

    2000-01-01

    Distortion of a -150fs optical pulse after propagation through an InAs/InGaAs quantum-dot optical amplifier is measured for different input energies an bias currents. Pulse distortion is observed and compared with results on a bulk amplifier.......Distortion of a -150fs optical pulse after propagation through an InAs/InGaAs quantum-dot optical amplifier is measured for different input energies an bias currents. Pulse distortion is observed and compared with results on a bulk amplifier....

  6. Microwave dynamic large signal waveform characterization of advanced InGaP HBT for power amplifiers

    Institute of Scientific and Technical Information of China (English)

    Zhao Lixin; Jin Zhi; Liu Xinyu

    2009-01-01

    In wireless mobile communications and wireless local area networks (WLAN), advanced lnGaP HBT with power amplifiers are key components. In this paper, the microwave large signal dynamic waveform characteristics of an advanced InGaP HBT are investigated experimentally for 5.8 GHz power amplifier applications. The microwave large signal waveform distortions at various input power levels, especially at large signal level, are investigated and the reasons are analyzed. The output power saturation is also explained. These analyses will be useful for power amplifier designs.

  7. Constraints on dark matter interactions with standard model particles from CMB spectral distortions

    CERN Document Server

    Ali-Haïmoud, Yacine; Kamionkowski, Marc

    2015-01-01

    We propose a new method to constrain elastic scattering between dark matter (DM) and standard model particles in the early Universe. Direct or indirect thermal coupling of non-relativistic DM with photons leads to a heat sink for the latter. This results in spectral distortions of the cosmic microwave background (CMB), the amplitude of which can be as large as a few times the DM-to-photon number ratio. We compute CMB spectral distortions due to DM-proton, DM-electron and DM-photon scattering for generic energy-dependent cross sections and DM mass m_DM >~ 1 keV. Using FIRAS measurements we set constraints on the cross sections for m_DM <~ 0.1 MeV. In particular, for energy-independent scattering we obtain sigma[DM-proton] <~ 10^(-24) cm^2 (keV/m_DM)^(1/2), sigma[DM-electron] <~ 10^(-27) cm^2 (keV/m_DM)^(1/2) and sigma[DM-photon] <~ 10^(-39) cm^2 (m_DM/keV). An experiment with the characteristics of PIXIE would extend the regime of sensitivity up to masses m_DM ~ 1 GeV.

  8. Cognitive Distortions in Depressed Women: Trait, or State Dependent?

    Directory of Open Access Journals (Sweden)

    Sedat BATMAZ

    2016-07-01

    Full Text Available Objective: According to the cognitive theory developed by Beck, cognitive distortions are important mediators for the onset and maintenance of depressive disorders. It has not been researched if these cognitive distortions are more frequently encountered during the depressive episode, or if they are trait-like features. This study aims to investigate this. The hypothesis of the study is that cognitive distortions are state dependent. Method: Three groups of outpatients (n=178 patients in acute major depressive episode, n=168 depressive patients in remission, n=177 healthy controls presenting to the psychiatry clinics of three different state hospitals were recruited for the study. The participants were diagnostically interviewed by the MINI according to the DSM-IV criteria. The participants were asked to complete the Cognitive Distortions Scale and the severity of their depression was measured by the Inventory for Depressive Symptomatology. Results: According to the cognitive distortion subscales, except for the self-blame subscale, the acute depressive group scored the highest. Also it was found that the cognitive distortions of the depressive populations, except for the self-blame related ones, statistically differed from the healthy controls’. Self-blame related distortions were mood state dependent. Conclusion: The results have revealed that self-criticism, helplessness, hopelessness and preoccupation with danger related distortions had trait-like features, whereas selfblame related distortions were state dependent. This has clinical implications for the psychotherapeutic treatment of cognitive distortions in depression. Specifically, self-criticism related distortions should be managed during cognitive therapy for depression since the other subscales seem rather problematic.

  9. Microwave Radiation Hazards

    Directory of Open Access Journals (Sweden)

    G. Subrahmanian

    1973-07-01

    Full Text Available Excessive exposure to microwave radiation could lead to biological damage. The criteria for maximum permissible exposure limits derived from experiments by several countries are discussed. Recommendations made for safety of operating personnel based on a recent protection survey are also presented.

  10. Leakage of Microwave Ovens

    Science.gov (United States)

    Abdul-Razzaq, W.; Bushey, R.; Winn, G.

    2011-01-01

    Physics is essential for students who want to succeed in science and engineering. Excitement and interest in the content matter contribute to enhancing this success. We have developed a laboratory experiment that takes advantage of microwave ovens to demonstrate important physical concepts and increase interest in physics. This experiment…

  11. Leakage of Microwave Ovens

    Science.gov (United States)

    Abdul-Razzaq, W.; Bushey, R.; Winn, G.

    2011-01-01

    Physics is essential for students who want to succeed in science and engineering. Excitement and interest in the content matter contribute to enhancing this success. We have developed a laboratory experiment that takes advantage of microwave ovens to demonstrate important physical concepts and increase interest in physics. This experiment…

  12. Invisible to Microwaves

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Scientists can't yet make an invisibility cloak like the one that Harry Potter uses.But,for the first time,they've constructed a simple cloaking(1)d__that makes itself and something placed inside it invisible to microwaves.

  13. Continuous image distortion by astrophysical thick lenses

    CERN Document Server

    Kling, Thomas P

    2011-01-01

    Image distortion due to weak gravitational lensing is examined using a non-perturbative method of integrating the geodesic deviation and optical scalar equations along the null geodesics connecting the observer to a distant source. The method we develop continuously changes the shape of the pencil of rays from the source to the observer with no reference to lens planes in astrophysically relevant scenarios. We compare the projected area and the ratio of semi-major to semi-minor axes of the observed elliptical image shape for circular sources from the continuous, thick-lens method with the commonly assumed thin-lens approximation. We find that for truncated singular isothermal sphere and NFW models of realistic galaxy clusters, the commonly used thin-lens approximation is accurate to better than 1 part in 10^4 in predicting the image area and axes ratios. For asymmetric thick lenses consisting of two massive clusters separated along the line of sight in redshift up to \\Delta z = 0.2, we find that modeling the ...

  14. Use of distorted waves in the theory of inelastic scattering

    Science.gov (United States)

    Picklesimer, A.; Tandy, P. C.; Thaler, R. M.

    1982-03-01

    A distorted wave description of inelastic scattering of nucleons from nuclei is formulated so that the microscopic content of the various ingredients can be made explicit. Special care is taken to ensure that physical processes are not overcounted as a consequence of the use of distorted waves in both the initial and final channels. Two attitudes to applications of the theory are taken. In the first, it is assumed that phenomenological distorted waves are employed and attention is focused upon the microscopic transition potential and the final distorted wave. Theoretically based recommendations for practical calculations of both these quantities are given. Secondly, we present a completely microscopic treatment wherein the truncations of the microscopic distorting potentials and the transition potential, at the single scattering level, are consistent with the underlying theoretical framework which links them. Our approach is designed to embody the distorted wave impulse approximation as a suitable lowest order result. Again, recommendations for practical calculations are given. NUCLEAR REACTIONS Inelastic scattering, distorted wave Born approximation, distorted wave impulse approximation, multiple scattering.

  15. Computing Welding Distortion: Comparison of Different Industrially Applicable Methods

    NARCIS (Netherlands)

    Tikhomirov, D.; Rietman, B.; Kose, K.; Makkink, M.

    2005-01-01

    Welding distortion is one of the major concerns of the industrial joining practice. In order to obtain optimal welding parameters many experiments have to be carried out. Numerical simulation enables a virtual examination of the welding distortion without performing expensive experiments. In this co

  16. Quality Prediction of Asymmetrically Distorted Stereoscopic 3D Images.

    Science.gov (United States)

    Wang, Jiheng; Rehman, Abdul; Zeng, Kai; Wang, Shiqi; Wang, Zhou

    2015-11-01

    Objective quality assessment of distorted stereoscopic images is a challenging problem, especially when the distortions in the left and right views are asymmetric. Existing studies suggest that simply averaging the quality of the left and right views well predicts the quality of symmetrically distorted stereoscopic images, but generates substantial prediction bias when applied to asymmetrically distorted stereoscopic images. In this paper, we first build a database that contains both single-view and symmetrically and asymmetrically distorted stereoscopic images. We then carry out a subjective test, where we find that the quality prediction bias of the asymmetrically distorted images could lean toward opposite directions (overestimate or underestimate), depending on the distortion types and levels. Our subjective test also suggests that eye dominance effect does not have strong impact on the visual quality decisions of stereoscopic images. Furthermore, we develop an information content and divisive normalization-based pooling scheme that improves upon structural similarity in estimating the quality of single-view images. Finally, we propose a binocular rivalry-inspired multi-scale model to predict the quality of stereoscopic images from that of the single-view images. Our results show that the proposed model, without explicitly identifying image distortion types, successfully eliminates the prediction bias, leading to significantly improved quality prediction of the stereoscopic images.

  17. Socioeconomic Inequality and Giftedness: Suppression and Distortion of High Ability

    Science.gov (United States)

    Ambrose, Don

    2013-01-01

    Severe socioeconomic inequality strongly suppresses and distorts the discovery of aspirations and the concomitant development of talents among the gifted. More comprehensive understanding of this suppression and distortion is available through a wide-ranging interdisciplinary search for research findings and theories that illuminate economic,…

  18. Improved neural network modeling of inverse lens distortion

    CSIR Research Space (South Africa)

    De Villiers, JP

    2011-04-01

    Full Text Available Inverse lens distortion modelling allows one to find the pixel in a distorted image which corresponds to a known point in object space, such as may be produced by a RADAR. This paper extends recent work using neural networks as a compromise between...

  19. Coulomb distortion effects in deep-inelastic electron scattering

    Science.gov (United States)

    Co', Giampaolo; Heisenberg, Jochen

    1987-11-01

    The effects of the Coulomb distortion of the electron wave functions in the description of the electron scattering processes in the quasi-elastic region are discussed. A method to extract longitudinal and transverse response functions considering these effects is presented. While the transverse response function is remarkably affected by the Coulomb distortion, the values of the longitudinal response function are practically unchanged.

  20. Quadratic elongation: A quantitative measure of distortion in coordination polyhedra

    Science.gov (United States)

    Robinson, Kelly F.; Gibbs, G.V.; Ribbe, P.H.

    1971-01-01

    Quadratic elongation and the variance of bond angles are linearly correlated for distorted octahedral and tetrahedral coordination complexes, both of which show variations in bond length and bond angle. The quadratic elonga tion is dimensionless, giving a quantitative measure of polyhedral distortion which is independent of the effective size of the polyhedron.

  1. Mass spectral peak distortion due to Fourier transform signal processing.

    Science.gov (United States)

    Rockwood, Alan L; Erve, John C L

    2014-12-01

    Distortions of peaks can occur when one uses the standard method of signal processing of data from the Orbitrap and other FT-based methods of mass spectrometry. These distortions arise because the standard method of signal processing is not a linear process. If one adds two or more functions, such as time-dependent signals from a Fourier transform mass spectrometer and performs a linear operation on the sum, the result is the same as if the operation was performed on separate functions and the results added. If this relationship is not valid, the operation is non-linear and can produce unexpected and/or distorted results. Although the Fourier transform itself is a linear operator, the standard algorithm for processing spectra in Fourier transform-based methods include non-linear mathematical operators such that spectra processed by the standard algorithm may become distorted. The most serious consequence is that apparent abundances of the peaks in the spectrum may be incorrect. In light of these considerations, we performed theoretical modeling studies to illustrate several distortion effects that can be observed, including abundance distortions. In addition, we discuss experimental systems where these effects may manifest, including suggested systems for study that should demonstrate these peak distortions. Finally, we point to several examples in the literature where peak distortions may be rationalized by the phenomena presented here.

  2. Distortion of Probability and Outcome Information in Risky Decisions

    Science.gov (United States)

    DeKay, Michael L.; Patino-Echeverri, Dalia; Fischbeck, Paul S.

    2009-01-01

    Substantial evidence indicates that information is distorted during decision making, but very few studies have assessed the distortion of probability and outcome information in risky decisions. In two studies involving six binary decisions (e.g., banning blood donations from people who have visited England, because of "mad cow disease"),…

  3. Computing Welding Distortion: Comparison of Different Industrially Applicable Methods

    NARCIS (Netherlands)

    Tikhomirov, D.; Rietman, Bert; Kose, K.; Makkink, M.

    2005-01-01

    Welding distortion is one of the major concerns of the industrial joining practice. In order to obtain optimal welding parameters many experiments have to be carried out. Numerical simulation enables a virtual examination of the welding distortion without performing expensive experiments. In this

  4. Predictors of Child Molestation: Adult Attachment, Cognitive Distortions, and Empathy

    Science.gov (United States)

    Wood, Eric; Riggs, Shelley

    2008-01-01

    A conceptual model derived from attachment theory was tested by examining adult attachment style, cognitive distortions, and both general and victim empathy in a sample of 61 paroled child molesters and 51 community controls. Results of logistic multiple regression showed that attachment anxiety, cognitive distortions, high general empathy but low…

  5. Understanding Pretrial Publicity: Predecisional Distortion of Evidence by Mock Jurors

    Science.gov (United States)

    Hope, Lorraine; Memon, Amina; McGeorge, Peter

    2004-01-01

    Prejudicial pretrial publicity (PTP) constitutes a serious source of juror bias. The current study examined differences in predecisional distortion for mock jurors exposed to negative PTP (N-PTP) versus nonexposed control participants. According to work by K. A. Carlson and J. E. Russo (2001), predecisional distortion occurs when jurors bias new…

  6. HTS nonlinearities in microwave disk resonators

    Science.gov (United States)

    Collado, Carlos; Mateu, Jordi; Shaw, Timothy J.; O'Callaghan, Juan M.

    2002-08-01

    This article describes a procedure for the calculation of the intermodulation behavior of the TM0 1 0 mode in high temperature superconducting (HTS) disk resonators from a description of the local HTS nonlinearities. Successful cross-checks are performed by comparing the theoretical results with experimental measurements and simulations based on the multiport harmonic balance algorithm for a specific model of HTS nonlinearity. The application of this procedure to the determination of nonlinear material parameters from disk resonator measurements is illustrated and compared to theoretical predictions.

  7. Modeling Kinetics of Distortion in Porous Bi-layered Structures

    DEFF Research Database (Denmark)

    Tadesse Molla, Tesfaye; Frandsen, Henrik Lund; Bjørk, Rasmus;

    2013-01-01

    Shape distortions during constrained sintering experiment of bi-layer porous and dense cerium gadolinium oxide (CGO) structures have been modeled. Technologies like solid oxide fuel cells require co-firing thin layers with different green densities, which often exhibit differential shrinkage...... because of different sintering rates of the materials resulting in undesired distortions of the component. An analytical model based on the continuum theory of sintering has been developed to describe the kinetics of densification and distortion in the sintering processes. A new approach is used...... to extract the material parameters controlling shape distortion through optimizing the model to experimental data of free shrinkage strains. The significant influence of weight of the sample (gravity) on the kinetics of distortion is taken in to consideration. The modeling predictions indicate good agreement...

  8. Nanostructure-induced distortion in single-emitter microscopy

    CERN Document Server

    Lim, Kangmook; Fourkas, John; Shapiro, Benjamin; Waks, Edo

    2016-01-01

    Single-emitter microscopy has emerged as a promising method of imaging nanostructures with nanoscale resolution. This technique uses the centroid position of an emitters far-field radiation pattern to infer its position to a precision that is far below the diffraction limit. However, nanostructures composed of high-dielectric materials such as noble metals can distort the far-field radiation pattern. Nanoparticles also exhibit a more complex range of distortions, because in addition to introducing a high dielectric surface, they also act as efficient scatterers. Thus, the distortion effects of nanoparticles in single-emitter microscopy remains poorly understood. Here we demonstrate that metallic nanoparticles can significantly distort the accuracy of single-emitter imaging at distances exceeding 300 nm. We use a single quantum dot to probe both the magnitude and the direction of the metallic nanoparticle-induced imaging distortion and show that the diffraction spot of the quantum dot can shift by more than 35...

  9. Distortional eigenmodes and solutions for thin-walled beams

    DEFF Research Database (Denmark)

    Andreassen, Michael Joachim; Jönsson, Jeppe

    2011-01-01

    This paper presents a generalization of the classic theory for thin-walled beams by including distortional displacements. A condensed presentation of the novel finite-elementbased displacement approach in [1,2] is given, where specific distortional displacement fields, which decouple the differen......This paper presents a generalization of the classic theory for thin-walled beams by including distortional displacements. A condensed presentation of the novel finite-elementbased displacement approach in [1,2] is given, where specific distortional displacement fields, which decouple...... found for the homogeneous system the final uncoupled set of distortional differential equations including the load terms are presented and the full solution is given, including an illustrative example. This new approach is an alternative to the traditional first order GBT method....

  10. Centi-pixel accurate real-time inverse distortion correction

    CSIR Research Space (South Africa)

    De Villiers, Johan P

    2008-11-01

    Full Text Available lens distortion model is that of Brown1, 2 and Conrady.3 The equation for Brown’s model is: xu =xd + (xd − xc)(K1r2 + K2r4 + . . .)+( P1(r2 + 2(xd − xc)2) + 2P2(xd − xc)(yd − yc))(1 + P3r2 + . . .) yu =yd + (yd − yc)(K1r2 + K2r4 + . . .)+( 2P1(xd... − xc)(yd − yc) + P2(r2 + 2(yd − yc)2))(1 + P3r2 + . . .)) (1) where: (xu, yu) = undistorted image point, (xd, yd) = distorted image point, (xc, yc) = centre of distortion, Kn = Nth radial distortion coefficient, Pn = Nth tangential distortion...

  11. Prussian phenomenon and its historical distortion

    Directory of Open Access Journals (Sweden)

    Oleg Y. Plenkov

    2016-03-01

    Full Text Available The article deals with the phenomenon of Prussia. Once, Prussia had been the largest continental Protestant state in Europe. The main issue of this phenomenon is that upon the tragic events of the World War II Prussian history and heritage had been considerably distorted, in order to compensate somehow for the dreadful casualties suffered by the victorious powers. The common European misconception implied that Prussia had been the bulwark of militarism, and therefore had to bear all the responsibility for the atrocities of war. Unfortunately, the majority of modern German historians share such misinterpretation of Prussian heritage in order to please false political correctness, perhaps, as an act of contrition for National Socialism and its crimes. However, the Prussian tradition and history go far beyond this militarism, and this article explains what ways. The authors believe that there should not be any prejudices and biases, that any subject should be examined sine ira et studio. Moreover, given that it is possible to characterize the Great French Revolution as a juristic one, and the Great October revolution – as a social one, the Prussian revolution “from above”, led by the first representatives of the Hohenzollern family, may be well considered as a pedagogical revolution. This revolution did bring definitely positive changes; they are surveyed in the article. The French Revolution has not eliminated the covetousness of the bourgeoisie after 1789; despotism of the authorities and people’s passiveness similarly have remained unaltered in Russia after 1917. On the contrary, Federal Republic of Germany of nowadays, distinctive for its law, order and effective responsible government is unthinkable without Prussian heritage.

  12. Redshift-space distortions around voids

    Science.gov (United States)

    Cai, Yan-Chuan; Taylor, Andy; Peacock, John A.; Padilla, Nelson

    2016-11-01

    We have derived estimators for the linear growth rate of density fluctuations using the cross-correlation function (CCF) of voids and haloes in redshift space. In linear theory, this CCF contains only monopole and quadrupole terms. At scales greater than the void radius, linear theory is a good match to voids traced out by haloes; small-scale random velocities are unimportant at these radii, only tending to cause small and often negligible elongation of the CCF near its origin. By extracting the monopole and quadrupole from the CCF, we measure the linear growth rate without prior knowledge of the void profile or velocity dispersion. We recover the linear growth parameter β to 9 per cent precision from an effective volume of 3( h-1Gpc)3 using voids with radius >25 h-1Mpc. Smaller voids are predominantly sub-voids, which may be more sensitive to the random velocity dispersion; they introduce noise and do not help to improve measurements. Adding velocity dispersion as a free parameter allows us to use information at radii as small as half of the void radius. The precision on β is reduced to 5 per cent. Voids show diverse shapes in redshift space, and can appear either elongated or flattened along the line of sight. This can be explained by the competing amplitudes of the local density contrast, plus the radial velocity profile and its gradient. The distortion pattern is therefore determined solely by the void profile and is different for void-in-cloud and void-in-void. This diversity of redshift-space void morphology complicates measurements of the Alcock-Paczynski effect using voids.

  13. Multiscale quantification of tissue spiculation and distortion for detection of architectural distortion and spiculated mass in mammography

    Science.gov (United States)

    Lao, Zhiqiang; Zheng, Xin

    2011-03-01

    This paper proposes a multiscale method to quantify tissue spiculation and distortion in mammography CAD systems that aims at improving the sensitivity in detecting architectural distortion and spiculated mass. This approach addresses the difficulty of predetermining the neighborhood size for feature extraction in characterizing lesions demonstrating spiculated mass/architectural distortion that may appear in different sizes. The quantification is based on the recognition of tissue spiculation and distortion pattern using multiscale first-order phase portrait model in texture orientation field generated by Gabor filter bank. A feature map is generated based on the multiscale quantification for each mammogram and two features are then extracted from the feature map. These two features will be combined with other mass features to provide enhanced discriminate ability in detecting lesions demonstrating spiculated mass and architectural distortion. The efficiency and efficacy of the proposed method are demonstrated with results obtained by applying the method to over 500 cancer cases and over 1000 normal cases.

  14. The Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Jones Aled

    1998-01-01

    Full Text Available We present a brief review of current theory and observations of the cosmic microwave background (CMB. New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique based on Bayesian statistics that can be used to reconstruct the underlying sky fluctuations is summarised. Current CMB data is used to set some preliminary constraints on the values of fundamental cosmological parameters $Omega$ and $H_circ$ using the maximum likelihood technique. In addition, secondary anisotropies due to the Sunyaev-Zel'dovich effect are described.

  15. Bilateral Symmetry of Distortions of Tactile Size Perception.

    Science.gov (United States)

    Longo, Matthew R; Ghosh, Arko; Yahya, Tasneem

    2015-01-01

    The perceived distance between touches on the limbs is generally bigger for distances oriented across the width of the limb than for distances oriented along the length of the limb. The present study aimed to investigate the coherence of such distortions of tactile size perception across different skin surfaces. We investigated distortions of tactile size perception on the dorsal and palmar surfaces of both the left and right hands as well as the forehead. Participants judged which of two tactile distances felt larger. One distance was aligned with the proximodistal axis (along the body), the other with the mediolateral axis (across the body). Clear distortions were found on all five skin surfaces, with stimuli oriented across the width of the body being perceived as farther apart than those oriented along the length of the body. Consistent with previous results, distortions were smaller on the palmar than on the dorsal hand surface. Distortion on the forehead was intermediate between the dorsal and palmar surfaces. There were clear correlations between distortion on the left and right hands, for both the dorsal and palmar skin surfaces. In contrast, within each hand, there was no significant correlation between the two skin surfaces. Distortion on the forehead was not significantly correlated with that on any of the other skin surfaces. These results provide evidence for bilaterally symmetric representations underlying tactile size perception.

  16. Microwave Processing of Materials

    Science.gov (United States)

    1994-01-01

    Pennsylvania: Materials Research Society. Wagner, C., and W. Schottky. 1930. Zeitschrift fuer Physikalische Chemie. BL11:163. Walkiewicz, J. W., A. E. Clark...Science and Engineering. 66:468--469. Bloch, F. 1928. Zeitschrift fuer Physik. 52:555. Boch, P., N. Lequeux and P. Piluso. 1992. Reaction Sintering...Frankel, J. 1926. Zeitschrift fuer Physik. 35:652. Fukushima, H., T. Yamaka, and M. Matsui. 1990. Microwave Heating of Ceramics and its Application to

  17. SUNIST Microwave Power System

    Institute of Scientific and Technical Information of China (English)

    Feng Songlin; Yang Xuanzong; Feng Chunhua; Wang Long; Rao Jun; Feng Kecheng

    2005-01-01

    Experiments on the start-up and formation of spherical tokamak plasmas by electron cyclotron heating alone without ohmic heating and electrode discharge assisted electron cyclotron wave current start-up will be carried out on the SUNIST (Sino United Spherical Tokamak) device.The 2.45 GHz/100 kW/30 ms microwave power system and 1000 V/50 A power supply for electrode discharge are ready for experiments with non-inductive current drive.

  18. Microwave Multicomponent Synthesis

    Directory of Open Access Journals (Sweden)

    Helmut M. Hügel

    2009-12-01

    Full Text Available In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules is growing in importance. This review will explore the advances and advantages in microwave multicomponent synthesis (MMS that have been achieved over the last five years.

  19. Strain and lattice distortion in semiconductor strain and lattice distortion in semiconductor structures

    CERN Document Server

    Luebbert, D

    2000-01-01

    waves in crystals. This thesis presents newly developed X-ray methods which can be used to characterize in detail the state of distortion of the crystal lattice in semiconductor wafers, devices and nanostructures. The methods use the extraordinary properties of the X-rays available from modern synchrotron sources such as the ESRF (Grenoble). In the first part of the thesis, X-ray diffractometry and X-ray topography are combined into a new method, called X-ray rocking curve imaging, which allows to image the macroscopic curvature of semiconductor wafers as well as the underlying microscopic defect structure.The second part of the thesis deals with the investigation of epitaxially grown and subsequently etched semiconductor gratings with lateral periods below the micrometer. The lattice mismatch between the different materials used in heteroepitaxy leads to a non-uniform strain field in the sample, which is reflected in a characteristic distortion of the X-ray diffraction pattern around each Bragg peak. The exp...

  20. Microwave sterilization method and apparatus

    OpenAIRE

    V. N. Vasilenko; Minuhin, V. V.; Podorozhnyak, A. A.; Trubaev, S. I.

    1995-01-01

    Experience of industrially developed countries in utilization of microwave radiation has been analyzed. Apparatus for realization of microwave method of sterilization has been designed. A number of experiments for the estimation of bactericidal, sporacidal, and virusidal properties of microwave radiation action has been carried out in 3 to 13 cm wavelength band. B. Lycheniform shtumm G., B. Subtilis ATTC 6633, E. Coli ATTC 25922 and bacterial virus FX 174 were used as test microbes. Effect of...

  1. Introduction to Microwave Linear [Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Whittum, David H

    1999-01-04

    The elements of microwave linear accelerators are introduced starting with the principles of acceleration and accelerating structures. Considerations for microwave structure modeling and design are developed from an elementary point of view. Basic elements of microwave electronics are described for application to the accelerator circuit and instrumentation. Concepts of beam physics are explored together with examples of common beamline instruments. Charged particle optics and lattice diagnostics are introduced. Considerations for fixed-target and colliding-beam experimentation are summarized.

  2. Microwave-Assisted Olefin Metathesis

    Science.gov (United States)

    Nicks, François; Borguet, Yannick; Sauvage, Xavier; Bicchielli, Dario; Delfosse, Sébastien; Delaude, Lionel; Demonceau, Albert

    Since the first reports on the use of microwave irradiation to accelerate organic chemical transformations, a plethora of papers have been published in this field. In most examples, microwave heating has been shown to dramatically reduce reaction times, increase product yields, and enhance product purity by reducing unwanted side reactions compared to conventional heating methods. The present contribution aims at illustrating the advantages of this technology in olefin metathesis and, when data are available, at comparing microwave-heated and conventionally heated experiments

  3. An Evaluation Method for Distortion Energy Parameterization of Triangular Meshes

    Institute of Scientific and Technical Information of China (English)

    SHI Jing; ZHAO Xiu-yang; ZHANG Cai-ming; YANG Bo

    2013-01-01

    Parameterization of triangle meshes is a fundamental problem for texture mapping, surface fitting, surface reconstruction, and mesh editing. The deformation of triangular meshes caused by the parameterized process is the measurement of parameterization. Traditional standard method has its limitation when evaluating mixture distortion energy parameterizations. Thus an evaluation method bases on distortion energy parameterization of triangular meshes is introduced for the limitation. The novel method employs an adaptive expression form to the mixture energy, and uses a weight factor to represent distortion energy distribution. By using this method, we can evaluate all kinds of parameterization in a uniform measurement and acquire a more intuitive and clear evaluation.

  4. Bond—Valence Sum and Distortion of Coordination Polyhedra

    Institute of Scientific and Technical Information of China (English)

    章礼明

    1993-01-01

    By using the Lagrange's intermediate value theorem,it is derived mathematically that the structur-al distortion of a coordination polyhedron may lead to an increase in bond-valence sum of the cen-tral atom of ion .The applicabilities of the bond-valence model are discussed in the following two cases:the modeling of crystal structure ,and the indication of distortion degree of a coordination polyhedron.Also it is shown that a distorted polyhedron should be in favor of a longer average bond length or a smaller coordination number.

  5. Achieving the Gaussian Rate-Distortion Function by Prediction

    CERN Document Server

    Zamir, Ram; Erez, Uri

    2007-01-01

    The "water-filling" solution for the quadratic rate-distortion function of a stationary Gaussian source is given in terms of its power spectrum. This formula naturally lends itself to a frequency domain "test-channel" realization. We provide an alternative time-domain realization for the rate-distortion function, based on linear prediction. This solution has some interesting implications, including the optimality at all distortion levels of pre/post filtered vector-quantized differential pulse code modulation (DPCM), and a duality relationship with decision-feedback equalization (DFE) for inter-symbol interference (ISI) channels.

  6. Operation of static series compensator under distorted utility conditions

    DEFF Research Database (Denmark)

    Awad, H.; Nelsen, H.; Blaabjerg, Frede

    2005-01-01

    in the case of distorted grid voltage. Furthermore, a selective harmonic compensation strategy is applied to filter out the grid harmonics. The operation of the SSC under distorted utility conditions and voltage dips is discussed. The validity of the proposed controller is verified by experiments, carried out...... on a 10-kV SSC laboratory setup. Experimental results have shown the ability of the SSC to mitigate voltage dips and harmonics. It is also shown that the proposed controller has improved the transient performance of the SSC even under distorted utility conditions....

  7. Numerical modeling of microwave heating

    Directory of Open Access Journals (Sweden)

    Shukla A.K.

    2010-01-01

    Full Text Available The present study compares the temperature distribution within cylindrical samples heated in microwave furnace with those achieved in radiatively-heated (conventional furnace. Using a two-dimensional finite difference approach the thermal profiles were simulated for cylinders of varying radii (0.65, 6.5, and 65 cm and physical properties. The influence of susceptor-assisted microwave heating was also modeled for the same. The simulation results reveal differences in the heating behavior of samples in microwaves. The efficacy of microwave heating depends on the sample size and its thermal conductivity.

  8. Evolution of the linear-polarization-angle-dependence of the radiation-induced magnetoresistance-oscillations with microwave power

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Tianyu; Mani, R. G. [Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303 (United States); Wegscheider, W. [Laboratorium für Festkörperphysik, ETH Zürich, 8093 Zürich (Switzerland)

    2014-11-10

    We examine the role of the microwave power in the linear polarization angle dependence of the microwave radiation induced magnetoresistance oscillations observed in the high mobility GaAs/AlGaAs two dimensional electron system. The diagonal resistance R{sub xx} was measured at the fixed magnetic fields of the photo-excited oscillatory extrema of R{sub xx} as a function of both the microwave power, P, and the linear polarization angle, θ. Color contour plots of such measurements demonstrate the evolution of the lineshape of R{sub xx} versus θ with increasing microwave power. We report that the non-linear power dependence of the amplitude of the radiation-induced magnetoresistance oscillations distorts the cosine-square relation between R{sub xx} and θ at high power.

  9. The Microwave SQUID Multiplexer

    Science.gov (United States)

    Mates, John Arthur Benson

    2011-12-01

    This thesis describes a multiplexer of Superconducting Quantum Interference Devices (SQUIDs) with low-noise, ultra-low power dissipation, and great scalability. The multiplexer circuit measures the magnetic flux in a large number of unshunted rf SQUIDs by coupling each SQUID to a superconducting microwave resonator tuned to a unique resonance frequency and driving the resonators from a common feedline. A superposition of microwave tones measures each SQUID simultaneously using only two coaxial cables between the cryogenic device and room temperature. This multiplexer will enable the instrumentation of arrays with hundreds of thousands of low-temperature detectors for new applications in cosmology, materials analysis, and nuclear non-proliferation. The driving application of the Microwave SQUID Multiplexer is the readout of large arrays of superconducting transition-edge sensors, by some figures of merit the most sensitive detectors of electromagnetic signals over a span of more than nine orders of magnitude in energy, from 40 GHz microwaves to 200 keV gamma rays. Modern transition-edge sensors have noise-equivalent power as low as 10-20 W / Hz1/2 and energy resolution as good as 2 eV at 6 keV. These per-pixel sensitivities approach theoretical limits set by the underlying signals, motivating a rapid increase in pixel count to access new science. Compelling applications, like the non-destructive assay of nuclear material for treaty verification or the search for primordial gravity waves from inflation use arrays of these detectors to increase collection area or tile a focal plane. We developed three generations of SQUID multiplexers, optimizing the first for flux noise 0.17 muPhi0 / Hz1/2, the second for input current noise 19 pA / Hz1/2, and the last for practical multiplexing of large arrays of cosmic microwave background polarimeters based on transition-edge sensors. Using the last design we demonstrated multiplexed readout of prototype polarimeters with the

  10. Non-Ionizing Radiation Used in Microwave Ovens

    Science.gov (United States)

    ... in Microwave Ovens Non-Ionizing Radiation Used in Microwave Ovens Explore the interactive, virtual community of RadTown USA ! ... learn more About Non-Ionizing Radiation Used in Microwave Ovens Microwave Oven. Microwave ovens use electromagnetic waves that ...

  11. Infrared and microwave study of angular-radial coupling effects in Ar-HCN

    Science.gov (United States)

    Fraser, G. T.; Pine, A. S.

    1989-09-01

    Microwave and infrared spectra of Ar-HCN have been obtained using an electric-resonance optothermal spectrometer. The microwave measurements extend to higher J the previous results of Leopold et al. and Klots et al., allowing the determination of higher-order centrifugal distortion constants for this quasilinear, highly nonrigid complex. A Padé approximant fit to the microwave data indicates a significant rotation-induced asymptotic increase in the zero-point center-of-mass separation between the Ar and the HCN, above that expected from pure radial distortion. This results from the large coupling between the angular and radial degrees in the intermolecular potential forcing the centrifugal alignment of the HCN. Infrared spectra are reported for the C-H streching fundamental ν1 and the combination band ν1+ν15, where ν5 is the van der Waals bending vibration. The band-origin difference between these two bands gives ν5=7.8 cm-1, in rough agreement with the 10 cm-1 harmonic value predicted from the microwave-determined nuclear quadrupole coupling constant. The complexation-induced red shift of the C-H stretching vibration is 2.69 cm-1 and the vibrational predissociation linewidths Γ are <10 MHz (FWHM). The vibrationally excited complex predissociates before striking the bolometer detector, implying that the predissociation lifetime τ<1 ms.

  12. Microwave Plasma System: PVA Tepla 300

    Data.gov (United States)

    Federal Laboratory Consortium — Description: CORAL Name: Microwave Asher A tool using microwave oxygen plasma to remove organics on the surfaces Specifications / Capabilities: Frequency: 2.45 GHz...

  13. The European Microwave Week 2008 and its Microwave Conferences

    NARCIS (Netherlands)

    Hoogeboom, P.; Van Vliet, F.

    2009-01-01

    Under the auspices of the European Microwave Association (EuMA) the 11th annual European Microwave Week was organized in the Amsterdam RAI Congress Centre, The Netherlands, 27-31 October 2008. This major event consisted this year of five conferences, an exhibition, and various side events. The 38th

  14. Mitigation of Engine Inlet Distortion Through Adjoint-Based Design

    Science.gov (United States)

    Ordaz, Irian; Rallabhandi, Sriram; Nielsen, Eric J.; Diskin, Boris

    2017-01-01

    The adjoint-based design capability in FUN3D is extended to allow efficient gradient- based optimization and design of concepts with highly integrated aero-propulsive systems. A circumferential distortion calculation, along with the derivatives needed to perform adjoint-based design, have been implemented in FUN3D. This newly implemented distortion calculation can be used not only for design but also to drive the existing mesh adaptation process and reduce the error associated with the fan distortion calculation. The design capability is demonstrated by the shape optimization of an in-house aircraft concept equipped with an aft fuselage propulsor. The optimization objective is the minimization of flow distortion at the aerodynamic interface plane of this aft fuselage propulsor.

  15. Labor Market Distortions in Côte d'Ivoire:

    DEFF Research Database (Denmark)

    Kristensen, Nicolai; Verner, Dorte

    2008-01-01

    This paper investigates the extent and nature of distortions in the labor market in the Republic of Côte d'Ivoire by using quantile regression analysis on employer-employee data from the manufacturing sector. We found that the labor markets in Côte d'Ivoire do not seem to be much distorted. Union...... in the absence of unions, segmentation and inefficiencies will still be present as long as firms seek to retain their employees by paying wages above the market clearing level. The inefficiency arising from establishment-size wage effects can be mitigated by education.......This paper investigates the extent and nature of distortions in the labor market in the Republic of Côte d'Ivoire by using quantile regression analysis on employer-employee data from the manufacturing sector. We found that the labor markets in Côte d'Ivoire do not seem to be much distorted. Unions...

  16. Electronic bidirectional valve circuit prevents crossover distortion and threshold effect

    Science.gov (United States)

    Kernick, A.

    1966-01-01

    Four-terminal network forms a bidirectional valve which will switch or alternate an ac signal without crossover distortion or threshold effect. In this network, an isolated control signal is sufficient for circuit turn-on.

  17. Causal Rate Distortion Function and Relations to Filtering Theory

    CERN Document Server

    Charalambous, Charalambos D; Kourtellaris, Christos K

    2011-01-01

    A causal rate distortion function is defined, its solution is described, and its relation to filtering theory is discusssed. The relation to filtering is obtained via a causal constraint imposed on the reconstruction kernel to be realizable.

  18. MATHEMATICAL SIMULATION OF WELDING DISTORTIONS IN THIN PLATES

    Directory of Open Access Journals (Sweden)

    Afshin Kheidari Monfared

    2011-01-01

    Full Text Available Welding is a crucial manufacturing process and widely used for manufacturing various products including ships, automobiles, trains and bridges. Welding distortions often occur in welded structures of thin plates due to relatively low stiffness and result in their warpage during assembly process and high manufacturing cost. Therefore, prediction and reduction of welding distortions are important in order to improve quality of welded structures. Welding distortion during the assembly process is caused not only by local shrinkage due to rapid heating and cooling. 3-D thermo-elastic-plastic finite element method (FEM has been used to simulate single-bead-on-plate welding with 1 mm thickness. Experiments have been carried out to prove the simulated results. Comparison of the experimental results and FEM simulation results has confirmed that the proposed method efficiently  predicts level of  welding distortions while making single-bead-on-plate welding with 1 mm thickness.

  19. Adaptive interference hyperspectral image compression with spectrum distortion control

    Institute of Scientific and Technical Information of China (English)

    Jing Ma; Yunsong Li; Chengke Wu; Dong Chen

    2009-01-01

    As one of the next generation imaging spectrometers,interferential spectrometer has been paid much attention.With traditional spectrum compression methods,the hyperspectral images generated by interferential spectrometer can only be protected with better visual quality in spatial domain,but its optical applications in Fourier domain are often ignored.So the relation between the distortion in Fourier domain and the compression in spatial domain is analyzed in this letter.Based on this analysis,a novel coding scheme is proposed,which can compress data in spatial domain while reducing the distortion in Fourier domain.The bitstream of set partitioning in hierarchical trees (SPIHT) is truncated by adaptively lifting the rate-distortion slopes of zerotrees according to the priorities of optical path difference (OPD) based on rate-distortion optimization theory.Experimental results show that the proposed scheme can achieve better performance in Fourier domain while maintaining the image quality in spatial domain.

  20. Distortion outage minimization in Nakagami fading using limited feedback

    National Research Council Canada - National Science Library

    Wang, Chih-Hong; Dey, Subhrakanti

    2011-01-01

    .... The objective of this paper is to design clusterhead transmit power allocation policies to minimize the distortion outage probability at the fusion center, subject to an expected sum transmit power constraint...

  1. Harmonic distortions measured on board of a maritime vessel

    Science.gov (United States)

    Zburlea, Elena; Dordea, Stefan

    2016-12-01

    Measurements where performed on four channels by means of an autonomous equipment (galvanic separated and not supplied from the ship's mains) performed on board of some maritime transport vessels, inside the Port of Constanţa aquatorium. Distorted voltages where state in the distribution panels. The sources of those distortions are the switching power supplies of the electric drives. The novelty of our work states in performing those measurements during the inside port maneuvers, when the operating time of each electric equipment is non definable. Harmonic distortions caused by the switching power converters lower the Power Factor. There is no better manner to find out the main distortions sources on board of a maritime transport vessel than to perform the measurements directly, on each location.

  2. Correcting the Chromatic Aberration in Barrel Distortion of Endoscopic Images

    Directory of Open Access Journals (Sweden)

    Y. M. Harry Ng

    2003-04-01

    Full Text Available Modern endoscopes offer physicians a wide-angle field of view (FOV for minimally invasive therapies. However, the high level of barrel distortion may prevent accurate perception of image. Fortunately, this kind of distortion may be corrected by digital image processing. In this paper we investigate the chromatic aberrations in the barrel distortion of endoscopic images. In the past, chromatic aberration in endoscopes is corrected by achromatic lenses or active lens control. In contrast, we take a computational approach by modifying the concept of image warping and the existing barrel distortion correction algorithm to tackle the chromatic aberration problem. In addition, an error function for the determination of the level of centroid coincidence is proposed. Simulation and experimental results confirm the effectiveness of our method.

  3. Body Image Distortion and Pathological Eating Behaviors : Sociocultural Contributions

    OpenAIRE

    OMORI, Mika

    2000-01-01

    Body image distortion is often cited as a causal factor contributing to the development of eating disorders or pathological eating behaviors. Sociocultural factors, such as the societal preference for thinness and ...

  4. Correction of ultraviolet single photon counting image distortion

    Institute of Scientific and Technical Information of China (English)

    Xinghua Zhang; Baosheng Zhao; Zhenhua Miao; Wei Li; Xiangping Zhu; Yong'an Liu; Wei Zou

    2008-01-01

    Single photon counting imaging technology has been widely used in space environment detection, astronomy observation, nuclear physics, and ultraweak bioluminescence. However, the distortion of the single photon counting image will badly affect the measurement results. Therefore, the correction of distortion for single photon counting image is very significant. Ultraviolet single photon imaging system with wedge and strip anode is introduced and the influence factor leading to image distortion is analyzed. To correct original distorted image, three different image correction methods, namely, the physical correction, the global correction, and the local correction, are applied. In addition, two parameters, i.e, the position index and the linearity index, are defined to evaluate the performance of the three methods. The results suggest that the correction methods can improve the quality of the initial image without losing gray information of each counting light spot. And the local correction can provide the best visual inspections and performance evaluation among the three methods.

  5. Elliptical Galaxies: Rotationally Distorted, After All

    Directory of Open Access Journals (Sweden)

    Caimmi, R.

    2009-12-01

    .15$, and low rotationparameters $(0lechi_v^2<0.15$, while fastrotators show large ellipticities $(0.2lehat{e}<0.65$, large anisotropy parameters$(0.15ledelta<0.35$, and large rotationparameters $(0.15lechi_v^2<0.5$. Analternative kinematic classification withrespect to earlier attempts (Emsellem etal. 2007 requires larger samples for providingadditional support to the above mentionedresults. A possible interpretation of slowrotators as nonrotating at all and elongated due to negative anisotropy parameters,instead of flattened due to positiveanisotropy parameters, is exploited.Finally, the elliptical side of the Hubblemorphological sequence is interpreted as asequence of equilibrium (adjoint configurations where the ellipticity is an increasing functionof the rotation parameter, slow rotators correspond to early classes (E0-E2 in the oblate limit and E2-E0 in the prolate limitand fast rotators to late classes (E3-E6.In this view, boundaries are rotationally distorted regardless of angular momentumand stress tensor, where rotation has tobe intended as due to additional kinetic energy of tangential equatorial velocity components,with respect to spherical configurations with isotropic stress tensor.

  6. Parameterization of temperature and spectral distortions in future CMB experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pitrou, Cyril; Stebbins, Albert

    2014-10-15

    CMB spectral distortions are induced by Compton collisions with electrons. We review the various schemes to characterize the anisotropic CMB with a non-Planckian spectrum. We advocate using logarithmically averaged temperature moments as the preferred language to describe these spectral distortions, both for theoretical modeling and observations. Numerical modeling is simpler, the moments are frame-independent, and in terms of scattering the mode truncation is exact.

  7. Pulse Distortion in Saturated Fiber Optical Parametric Chirped Pulse Amplification

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Da Ros, Francesco; Rottwitt, Karsten

    2012-01-01

    Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation.......Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation....

  8. Can Personality Type Explain Heterogeneity in Probability Distortions?

    OpenAIRE

    C. Monica Capra; Bing Jiang; Jan Engelmann; Gregory Berns

    2012-01-01

    There are two regularities we have learned from experimental studies of choice under risk. The first is that the majority of people weigh objective probabilities non-linearly. The second regularity, although less commonly acknowledged, is that there is a large amount of heterogeneity in how people distort probabilities. Despite this, little effort has been made to identify the source of heterogeneity. In this paper, we explore the possibility that the probability distortions are linked to the...

  9. Can Personality Type Explain Heterogeneity in Probability Distortions?

    OpenAIRE

    C. Monica Capra; Bing Jiang; Jan Engelmann; Gregory Berns

    2012-01-01

    There are two regularities we have learned from experimental studies of choice under risk. The first is that the majority of people weigh objective probabilities non-linearly. The second regularity, although less commonly acknowledged, is that there is a large amount of heterogeneity in how people distort probabilities. Despite this, little effort has been made to identify the source of heterogeneity. In this paper, we explore the possibility that the probability distortions are linked to the...

  10. The effect of welding fixtures on welding distortions

    OpenAIRE

    2007-01-01

    Purpose: of this paper is to examine the effect of welding fixture used to prevent the distortions duringcooling process utilizing a robot controlled gas metal arc welding method on cooling rate and distortions ofwelded structures.Design/methodology/approach: Using a specially designed welding fixture for a welded steel structure, sixdifferent types of AISI 1020 steel specimens are tested in three different welding speeds and two differentcooling conditions either at fixture or without using ...

  11. Thermal distortion analysis of a deployable parabolic reflector

    Science.gov (United States)

    Bruck, L. R.; Honeycutt, G. H.

    1973-01-01

    A thermal distortion analysis of the ATS-6 Satellite parabolic reflector was performed using NASTRAN level 15.1. The same NASTRAN finite element method was used to conduct a one g static load analysis and a dynamic analysis of the reflector. In addition, a parametric study was made to determine which parameters had the greatest effect on the thermal distortions. The method used to model the construction of the reflector is described and the results of the analyses are presented.

  12. Nonlinear distortion in wireless systems modeling and simulation with Matlab

    CERN Document Server

    Gharaibeh, Khaled M

    2011-01-01

    This book covers the principles of modeling and simulation of nonlinear distortion in wireless communication systems with MATLAB simulations and techniques In this book, the author describes the principles of modeling and simulation of nonlinear distortion in single and multichannel wireless communication systems using both deterministic and stochastic signals. Models and simulation methods of nonlinear amplifiers explain in detail how to analyze and evaluate the performance of data communication links under nonlinear amplification. The book addresses the analysis of nonlinear systems

  13. Diagnosing perceptual distortion present in group stereoscopic viewing

    Science.gov (United States)

    Burton, Melissa; Pollock, Brice; Kelly, Jonathan W.; Gilbert, Stephen; Winer, Eliot; de la Cruz, Julio

    2012-03-01

    Stereoscopic displays are an increasingly prevalent tool for experiencing virtual environments, and the inclusion of stereo has the potential to improve distance perception within the virtual environment. When multiple users simultaneously view the same stereoscopic display, only one user experiences the projectively correct view of the virtual environment, and all other users view the same stereoscopic images while standing at locations displaced from the center of projection (CoP). This study was designed to evaluate the perceptual distortions caused by displacement from the CoP when viewing virtual objects in the context of a virtual scene containing stereo depth cues. Judgments of angles were distorted after leftward and rightward displacement from the CoP. Judgments of object depth were distorted after forward and backward displacement from the CoP. However, perceptual distortions of angle and depth were smaller than predicted by a ray-intersection model based on stereo viewing geometry. Furthermore, perceptual distortions were asymmetric, leading to different patterns of distortion depending on the direction of displacement. This asymmetry also conflicts with the predictions of the ray-intersection model. The presence of monocular depth cues might account for departures from model predictions.

  14. Economic choices reveal probability distortion in macaque monkeys.

    Science.gov (United States)

    Stauffer, William R; Lak, Armin; Bossaerts, Peter; Schultz, Wolfram

    2015-02-18

    Economic choices are largely determined by two principal elements, reward value (utility) and probability. Although nonlinear utility functions have been acknowledged for centuries, nonlinear probability weighting (probability distortion) was only recently recognized as a ubiquitous aspect of real-world choice behavior. Even when outcome probabilities are known and acknowledged, human decision makers often overweight low probability outcomes and underweight high probability outcomes. Whereas recent studies measured utility functions and their corresponding neural correlates in monkeys, it is not known whether monkeys distort probability in a manner similar to humans. Therefore, we investigated economic choices in macaque monkeys for evidence of probability distortion. We trained two monkeys to predict reward from probabilistic gambles with constant outcome values (0.5 ml or nothing). The probability of winning was conveyed using explicit visual cues (sector stimuli). Choices between the gambles revealed that the monkeys used the explicit probability information to make meaningful decisions. Using these cues, we measured probability distortion from choices between the gambles and safe rewards. Parametric modeling of the choices revealed classic probability weighting functions with inverted-S shape. Therefore, the animals overweighted low probability rewards and underweighted high probability rewards. Empirical investigation of the behavior verified that the choices were best explained by a combination of nonlinear value and nonlinear probability distortion. Together, these results suggest that probability distortion may reflect evolutionarily preserved neuronal processing. Copyright © 2015 Stauffer et al.

  15. Visual feedback distortion in a robotic environment for hand rehabilitation.

    Science.gov (United States)

    Brewer, Bambi Roberts; Klatzky, Roberta; Matsuoka, Yoky

    2008-04-15

    Robotic therapy offers a means of enhancing rehabilitation for individuals with chronic stroke or traumatic brain injury. The present research targets members of this population who demonstrate learned nonuse, a tendency to use affected limbs below the level of the individual's true capability. These individuals may not strive for difficult goals in therapy, which ultimately hampers their progress and the outcome of rehabilitation. Our research uses a paradigm called visual feedback distortion in which the visual feedback corresponding to force or distance is gradually changed by an imperceptible amount to encourage improved performance. Our first set of experiments was designed to assess the limits of imperceptible distortion for visual feedback concerning the force exerted or the distance moved by the index finger. A second set of experiments used these limits to gradually distort visual feedback in order to manipulate a subject's force or distance response. Based on this work, we designed a paradigm applying visual feedback distortion to the rehabilitation of individuals with chronic stroke and traumatic brain injury. Initial tests are reported for two subjects who participated in a six-week rehabilitation protocol. Each patient followed visual feedback distortion to levels of performance above that predicted by her performance during an initial assessment. Both patients showed functional improvements after participating in the study. Visual feedback distortion may provide a way to help a patient move beyond his or her self-assessed "best" performance, improving the outcome of robotic rehabilitation.

  16. The distortion tensor of magnetotellurics: a tutorial on some properties

    Science.gov (United States)

    Lilley, Frederick E. M.

    2016-05-01

    A 2 × 2 matrix is introduced which relates the electric field at an observing site where geological distortion applies to the regional electric field, which is unaffected by the distortion. For the student of linear algebra this matrix provides a practical example with which to demonstrate the basic and important procedures of eigenvalue analysis and singular value decomposition. The significance of the results can be visualised because the eigenvectors of such a telluric distortion matrix have a clear practical meaning, as do their eigenvalues. A Mohr diagram for the distortion matrix displays when real eigenvectors exist, and tells their magnitudes and directions. The results of singular value decomposition (SVD) also have a clear practical meaning. These results too can be displayed on a Mohr diagram. Whereas real eigenvectors may or may not exist, SVD is always possible. The ratio of the two singular values of the matrix gives a condition number, useful to quantify distortion. Strong distortion causes the matrix to approach the condition known as `singularity'. A closely-related anisotropy number may also be useful, as it tells when a 2 × 2 matrix has a negative determinant by then having a value greater than unity.

  17. Testing scenarios of primordial black holes being the seeds of supermassive black holes by ultracompact minihalos and CMB μ distortions

    Science.gov (United States)

    Kohri, Kazunori; Nakama, Tomohiro; Suyama, Teruaki

    2014-10-01

    Supermassive black holes and intermediate mass black holes are believed to exist in the Universe. There is no established astrophysical explanation for their origin, and considerations have been made in the literature that those massive black holes (MBHs) may be primordial black holes (PBHs), black holes which are formed in the early universe (well before the matter-radiation equality) due to the direct collapse of primordial overdensities. This paper aims at discussing the possibility of excluding the PBH scenario as the origin of the MBHs. We first revisit the constraints on PBHs obtained from the cosmic microwave background (CMB) distortion that the seed density perturbation causes. By adopting a recent computation of the CMB distortion sourced by the seed density perturbation and the stronger constraint on the CMB distortion set by the COBE/FIRAS experiment used in the literature, we find that PBHs in the mass range 6×104 M⊙-5×1013 M⊙ are excluded. Since PBHs lighter than 6×104 M⊙ are not excluded from the nonobservation of the CMB distortion, we propose a new method which can potentially exclude smaller PBHs as well. Based on the observation that large density perturbations required to create PBHs also result in the copious production of ultracompact minihalos (UCMHs), compact dark matter halos formed at around the recombination, we show that weakly interacting massive particles (WIMPs) as dark matter annihilate efficiently inside UCMHs to yield cosmic rays far exceeding the observed flux. Our bound gives severe restriction on the compatibility between the particle physics models for WIMPs and the PBH scenario as the explanation of MBHs.

  18. Microwave Sterilization in School Microbiology.

    Science.gov (United States)

    Wynn, Brian; Dixon, Angela

    1988-01-01

    Described are two investigations carried out in a high school biology department using a domestic microwave oven to compare the relative attributes of the autoclave and microwave oven in school use. Discussed are equipment, methods, and results of each investigation. (Author/CW)

  19. PROGRAMMING THE MICROWAVE-OVEN

    NARCIS (Netherlands)

    KOK, LP; VISSER, PE; BOON, ME

    1994-01-01

    Microwaves can be used to stimulate chemical bonding, diffusion of reagents into and out of the specimen, and coagulation processes in preparatory techniques. Temperature plays an important role in these processes. There are several ways of controlling the temperature of microwave-exposed tissue, fl

  20. More Experiments with Microwave Ovens

    Science.gov (United States)

    Vollmer, Michael; Mollmann, Klaus-Peter; Karstadt, Detlef

    2004-01-01

    Microwave ovens can be used to perform exciting demonstrations that illustrate a variety of physics topics. Experiments discussed here show superheating, visualize the inhomogeneous heating that takes place in a microwave and also show how to use a mobile phone to detect radiation leaking from the oven. Finally eggs can give some spectacular…

  1. More Experiments with Microwave Ovens

    Science.gov (United States)

    Vollmer, Michael; Mollmann, Klaus-Peter; Karstadt, Detlef

    2004-01-01

    Microwave ovens can be used to perform exciting demonstrations that illustrate a variety of physics topics. Experiments discussed here show superheating, visualize the inhomogeneous heating that takes place in a microwave and also show how to use a mobile phone to detect radiation leaking from the oven. Finally eggs can give some spectacular…

  2. PROGRAMMING THE MICROWAVE-OVEN

    NARCIS (Netherlands)

    KOK, LP; VISSER, PE; BOON, ME

    1994-01-01

    Microwaves can be used to stimulate chemical bonding, diffusion of reagents into and out of the specimen, and coagulation processes in preparatory techniques. Temperature plays an important role in these processes. There are several ways of controlling the temperature of microwave-exposed tissue,

  3. Passive Microwave Components and Antennas

    DEFF Research Database (Denmark)

    State-of-the-art microwave systems always require higher performance and lower cost microwave components. Constantly growing demands and performance requirements of industrial and scientific applications often make employing traditionally designed components impractical. For that reason, the design...... and development process remains a great challenge today. This problem motivated intensive research efforts in microwave design and technology, which is responsible for a great number of recently appeared alternative approaches to analysis and design of microwave components and antennas. This book highlights...... techniques. Modelling and computations in electromagnetics is a quite fast-growing research area. The recent interest in this field is caused by the increased demand for designing complex microwave components, modeling electromagnetic materials, and rapid increase in computational power for calculation...

  4. Passive Microwave Components and Antennas

    DEFF Research Database (Denmark)

    techniques. Modelling and computations in electromagnetics is a quite fast-growing research area. The recent interest in this field is caused by the increased demand for designing complex microwave components, modeling electromagnetic materials, and rapid increase in computational power for calculation......State-of-the-art microwave systems always require higher performance and lower cost microwave components. Constantly growing demands and performance requirements of industrial and scientific applications often make employing traditionally designed components impractical. For that reason, the design...... and development process remains a great challenge today. This problem motivated intensive research efforts in microwave design and technology, which is responsible for a great number of recently appeared alternative approaches to analysis and design of microwave components and antennas. This book highlights...

  5. Microwave plasma combustion of coal

    Energy Technology Data Exchange (ETDEWEB)

    P.M. Kanilo; V.I. Kazantsev; N.I. Rasyuk; K. Schuenemann; D.M. Vavriv [Institute of Machine Building Problems of the National Academy of Sciences of Ukraine, Kharkov (Ukraine)

    2003-01-01

    Microwave plasma is studied as an alternative to oil or gas fuel for ignition and stabilisation of burning of lean coal. The study is performed on an experimental set-up, which includes a burner with a microwave plasma generator, coal and air supply systems, and measurement equipment. Power and thermochemical characteristics of the coal-plasma interaction have been measured and analysed. The obtained results indicate an essential intensification of ignition and combustion processes in the microwave burner compared to those in conventional burners. In particular, it has been demonstrated that the microwave energy consumption is only about 10% of the required expenditure of oil or gas, measured in heat equivalent. A design of an industrial microwave-plasma burner is proposed. Prospects of such burner for applications at industrial boilers of power plants are discussed. 6 refs., 4 figs., 2 tabs.

  6. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU; TaJung

    2001-01-01

    The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.  ……

  7. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU TaJung

    2001-01-01

    @@ The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.

  8. Nanostructure-Induced Distortion in Single-Emitter Microscopy

    Science.gov (United States)

    Lim, Kangmook; Ropp, Chad; Barik, Sabyasachi; Fourkas, John; Shapiro, Benjamin; Waks, Edo

    2016-09-01

    Single-emitter microscopy has emerged as a promising method of imaging nanostructures with nanoscale resolution. This technique uses the centroid position of an emitters far-field radiation pattern to infer its position to a precision that is far below the diffraction limit. However, nanostructures composed of high-dielectric materials such as noble metals can distort the far-field radiation pattern. Nanoparticles also exhibit a more complex range of distortions, because in addition to introducing a high dielectric surface, they also act as efficient scatterers. Thus, the distortion effects of nanoparticles in single-emitter microscopy remains poorly understood. Here we demonstrate that metallic nanoparticles can significantly distort the accuracy of single-emitter imaging at distances exceeding 300 nm. We use a single quantum dot to probe both the magnitude and the direction of the metallic nanoparticle-induced imaging distortion and show that the diffraction spot of the quantum dot can shift by more than 35 nm. The centroid position of the emitter generally shifts away from the nanoparticle position, in contradiction to the conventional wisdom that the nanoparticle is a scattering object that will pull in the diffraction spot of the emitter towards its center. These results suggest that dielectric distortion of the emission pattern dominates over scattering. We also show that by monitoring the distortion of the quantum dot diffraction spot we can obtain high-resolution spatial images of the nanoparticle, providing a new method for performing highly precise, sub-diffraction spatial imaging. These results provide a better understanding of the complex near-field coupling between emitters and nanostructures, and open up new opportunities to perform super-resolution microscopy with higher accuracy.

  9. The thermal distortion of continuous-casting billet molds

    Science.gov (United States)

    Samarasekera, I. V.; Anderson, D. L.; Brimacombe, J. K.

    1982-03-01

    Preliminary mathematical analyses involving plate bending theory and two-dimensional elastic calculations have revealed that the dominant component contributing to the distortion of continuous-casting billet molds is thermal expansion in the transverse directions. A three-dimensional, elasto-plastic, finite-element analysis of the mold wall has then shown that localized yielding initiates in a region close to the meniscus. The plastic flow is a result of the high thermal stresses induced by the geometric restraint to bending coupled with the locally high temperatures. The resultant distortion profile of the mold down the centerline of a face exhibits a maximum outward bulge of 0.1 to 0.3 mm, which is bounded above by a region of negative taper (1˜2 pct/m) and below by a region of positive taper (˜0.4 pct/m). Measurements of mold wall movement in an operating billet caster using linear displacement transducers compare favorably with model predictions, except in the meniscus region. Case studies of several industrial billet molds have shown that lowering the meniscus level with respect to the location of constraints, or modifying the method of support of the mold tube within its housing so as to reduce the restraint to thermal expansion in the meniscus region, may minimize the extent of permanent distortion. Also, wall thickness can have a significant effect on thermal distortion. Increasing wall thickness results in an increase in both peak wall temperatures and thermal gradients. The former increases the local distortion while the latter causes higher thermal stress levels and possibly permanent distortion. Of the casting variables that can be manipulated to major advantage, cooling water flow rate is the most important. Increasing the water velocity reduces mold wall temperatures, as well as both the total and permanent distortion of the wall.

  10. Cognitive distortions among older adult gamblers in an Asian context.

    Science.gov (United States)

    Subramaniam, Mythily; Chong, Siow Ann; Browning, Colette; Thomas, Shane

    2017-01-01

    The study aims to describe the construct of cognitive distortions based on the narratives of older adult gamblers (aged 60 years and above) in Singapore. Singapore residents (citizens or permanent residents) aged 60 years and above, who were current or past regular gamblers were included in the study. Participants were recruited using a combination of venue based approach, referrals from service providers as well as by snowball sampling. In all, 25 in-depth interviews were conducted with older adult gamblers. The six-step thematic network analysis methodology was adopted for data analysis. The mean age of the participants was 66.2 years. The majority were male (n = 18), of Chinese ethnicity (n = 16), with a mean age of gambling initiation at 24.5 years. Among older adult gamblers, cognitive distortions emerged as a significant global theme comprising three organizing themes-illusion of control, probability control and interpretive control. The organizing themes comprised nine basic themes: perception of gambling as a skill, near miss, concept of luck, superstitious beliefs, entrapment, gambler's fallacy, chasing wins, chasing losses, and beliefs that wins are more than losses. Cognitive distortions were endorsed by all gamblers in the current study and were shown to play a role in both maintaining and escalating the gambling behaviour. While the surface characteristics of the distortions had a culture-specific appearance, the deeper characteristics of the distortions may in fact be more universal than previously thought. Future research must include longitudinal studies to understand causal relationships between cognitive distortions and gambling as well as the role of culture-specific distortions both in the maintenance and treatment of the disorder.

  11. Microwave systems design

    CERN Document Server

    Awang, Zaiki

    2014-01-01

    The aim of this book is to serve as a design reference for students and as an up-to-date reference for researchers. It also acts as an excellent introduction for newcomers to the field and offers established rf/microwave engineers a comprehensive refresher.  The content is roughly classified into two – the first two chapters provide the necessary fundamentals, while the last three chapters focus on design and applications. Chapter 2 covers detailed treatment of transmission lines. The Smith chart is utilized in this chapter as an important tool in the synthesis of matching networks for microwave amplifiers. Chapter 3 contains an exhaustive review of microstrip circuits, culled from various references. Chapter 4 offers practical design information on solid state amplifiers, while Chapter 5 contains topics on the design of modern planar filters, some of which were seldom published previously. A set of problems at the end of each chapter provides the readers with exercises which were compiled from actual uni...

  12. Microwave Frequency Multiplier

    Science.gov (United States)

    Velazco, J. E.

    2017-02-01

    High-power microwave radiation is used in the Deep Space Network (DSN) and Goldstone Solar System Radar (GSSR) for uplink communications with spacecraft and for monitoring asteroids and space debris, respectively. Intense X-band (7.1 to 8.6 GHz) microwave signals are produced for these applications via klystron and traveling-wave microwave vacuum tubes. In order to achieve higher data rate communications with spacecraft, the DSN is planning to gradually furnish several of its deep space stations with uplink systems that employ Ka-band (34-GHz) radiation. Also, the next generation of planetary radar, such as Ka-Band Objects Observation and Monitoring (KaBOOM), is considering frequencies in the Ka-band range (34 to 36 GHz) in order to achieve higher target resolution. Current commercial Ka-band sources are limited to power levels that range from hundreds of watts up to a kilowatt and, at the high-power end, tend to suffer from poor reliability. In either case, there is a clear need for stable Ka-band sources that can produce kilowatts of power with high reliability. In this article, we present a new concept for high-power, high-frequency generation (including Ka-band) that we refer to as the microwave frequency multiplier (MFM). The MFM is a two-cavity vacuum tube concept where low-frequency (2 to 8 GHz) power is fed into the input cavity to modulate and accelerate an electron beam. In the second cavity, the modulated electron beam excites and amplifies high-power microwaves at a frequency that is a multiple integer of the input cavity's frequency. Frequency multiplication factors in the 4 to 10 range are being considered for the current application, although higher multiplication factors are feasible. This novel beam-wave interaction allows the MFM to produce high-power, high-frequency radiation with high efficiency. A key feature of the MFM is that it uses significantly larger cavities than its klystron counterparts, thus greatly reducing power density and arcing

  13. The Liverpool Microwave Palaeointensity System

    Science.gov (United States)

    Hill, Mimi; Biggin, Andrew; Hawkins, Louise; Hodgson, Emma; Hurst, Elliot

    2016-04-01

    The motivation for the group at Liverpool in the 1990s (led by John Shaw and Derek Walton) to start experimenting with using microwaves to demagnetise and remagnetise palaeomagnetic samples, rather than heating using conventional ovens, was to reduce laboratory induced alteration in absolute palaeointensity experiments. As with other methods, the non-ideal effects of grain size and naturally altered remanence must still be addressed. From humble beginnings using a domestic microwave oven the current 4th generation microwave system (MWS) has developed in to an integrated combined 14 GHz microwave resonant cavity and SQUID magnetometer system. The MWS is designed to investigate one 5 mm diameter sample at a time with microwave exposure (the equivalent of a heating step in conventional experiments) ranging from a few seconds up to around a minute. Each experiment (protocol, checks, direction and strength of applied field, number of steps etc) can be tailored to the behaviour of each individual sample. There have been many published studies demonstrating the equivalence of conventional thermal (Thellier) and microwave techniques using both artificial and natural remanence and also that the microwave method can indeed reduce laboratory induced alteration. Here an overview of the present MWS including a discussion of the physical processes occurring will be given. Examples of current projects (both archaeological and geological) utilising the method will also be described. Finally, future developments and applications of the method will be discussed.

  14. An embedded still image coder with rate-distortion optimization.

    Science.gov (United States)

    Li, J; Lei, S

    1999-01-01

    It is well known that the fixed rate coder achieves optimality when all coefficients are coded with the same rate-distortion (R-D) slope. In this paper, we show that the performance of the embedded coder can be optimized in a rate-distortion sense by coding the coefficients with decreasing R-D slope. We denote such a coding strategy as rate-distortion optimized embedding (RDE). RDE allocates the available coding bits first to the coefficient with the steepest R-D slope, i.e., the largest distortion decrease per coding bit. The resultant coding bitstream can be truncated at any point and still maintain an optimal R-D performance. To avoid the overhead of coding order transmission, we use the expected R-D slope, which can be calculated from the coded bits and is available in both the encoder and the decoder. With the probability estimation table of the QM-coder, the calculation of the R-D slope can be just a lookup table operation. Experimental results show that the rate-distortion optimization significantly improves the coding efficiency in a wide bit rate range.

  15. Noise Shaping Filter Compensating PWM Distortion for Fully Digital Amplifier

    Science.gov (United States)

    Yoneya, Akihiko

    The full-digital audio amplifiers have several merits such as a high power enabling a small size of the amplifier and digital implementation of the signal processing which allows desired precision of the processing except for the final stage switching amplifiers. Unfortunately, the pulse width modulation (PWM) causes signal distortions because of the non-linearity of the modulation from the viewpoint of the transient response. This paper proposes a compensation method of the PWM distortion with feedback approach. In the noise-shaping filter of the delta-sigma modulator to calculate the pulse codes for the PWM, the distortion caused by the PWM is evaluated and fed it back to compensate the distortion. Eventually the filter is implemented as a state-variable filter with non-linear feedback from the quantizer. The calculation of the filter elements is also described. By using proposed filters, PWM signals with small distortions and small floor noise can be obtained to realize high-fidelity audio amplifiers.

  16. Distortion-Based Link Adaptation for Wireless Video Transmission

    Directory of Open Access Journals (Sweden)

    Andrew Nix

    2008-06-01

    Full Text Available Wireless local area networks (WLANs such as IEEE 802.11a/g utilise numerous transmission modes, each providing different throughputs and reliability levels. Most link adaptation algorithms proposed in the literature (i maximise the error-free data throughput, (ii do not take into account the content of the data stream, and (iii rely strongly on the use of ARQ. Low-latency applications, such as real-time video transmission, do not permit large numbers of retransmission. In this paper, a novel link adaptation scheme is presented that improves the quality of service (QoS for video transmission. Rather than maximising the error-free throughput, our scheme minimises the video distortion of the received sequence. With the use of simple and local rate distortion measures and end-to-end distortion models at the video encoder, the proposed scheme estimates the received video distortion at the current transmission rate, as well as on the adjacent lower and higher rates. This allows the system to select the link-speed which offers the lowest distortion and to adapt to the channel conditions. Simulation results are presented using the MPEG-4/AVC H.264 video compression standard over IEEE 802.11g. The results show that the proposed system closely follows the optimum theoretic solution.

  17. Geometric distortion of area in medical ultrasound images

    Science.gov (United States)

    Bland, T.; Tong, J.; Ward, B.; Parker, N. G.

    2017-01-01

    Medical ultrasound scanners are typically calibrated to a speed of sound corresponding to the soft tissue average of 1540 m s-1. In regions of different sound speed, for example, organs and tumours, the B-mode image becomes geometrically distorted from the true tissue cross-section, due to refraction and the misrepresentation of length. A ray model is developed to predict this distortion for a generalized two-dimensional object with atypical speed of sound, and verified against ultrasound images of a test object. We quantify the areal image distortion as a function of the key dependencies, including the speed of sound mismatch, the scanning format, the object size and its elongation. Our findings show that the distortion of area can be significant, even for relatively small speed of sound mismatches. For example, a 5% speed mismatch typically leads to a 10 - 20% distortion in area. These findings have implications for the accuracy of ultrasound-based evaluation of area and volume.

  18. Should sex-ratio distorting parasites abandon horizontal transmission?

    Directory of Open Access Journals (Sweden)

    Ironside Joseph E

    2011-12-01

    Full Text Available Abstract Background Sex-ratio distorting parasites are of interest due to their effects upon host population dynamics and their potential to influence the evolution of host sex determination systems. In theory, the ability to distort host sex-ratios allows a parasite with efficient vertical (hereditary transmission to dispense completely with horizontal (infectious transmission. However, recent empirical studies indicate that some sex-ratio distorting parasites have retained the capability for horizontal transmission. Results Numerical simulations using biologically realistic parameters suggest that a feminising parasite is only likely to lose the capability for horizontal transmission if its host occurs at low density and/or has a male-biased primary sex ratio. It is also demonstrated that even a small amount of horizontal transmission can allow multiple feminising parasites to coexist within a single host population. Finally it is shown that, by boosting its host's rate of population growth, a feminising parasite can increase its own horizontal transmission and allow the invasion of other, more virulent parasites. Conclusions The prediction that sex-ratio distorting parasites are likely to retain a degree of horizontal transmission has important implications for the epidemiology and host-parasite interactions of these organisms. It may also explain the frequent co-occurrence of several sex-ratio distorting parasite species in nature.

  19. Real-time lens distortion correction: speed, accuracy and efficiency

    Science.gov (United States)

    Bax, Michael R.; Shahidi, Ramin

    2014-11-01

    Optical lens systems suffer from nonlinear geometrical distortion. Optical imaging applications such as image-enhanced endoscopy and image-based bronchoscope tracking require correction of this distortion for accurate localization, tracking, registration, and measurement of image features. Real-time capability is desirable for interactive systems and live video. The use of a texture-mapping graphics accelerator, which is standard hardware on current motherboard chipsets and add-in video graphics cards, to perform distortion correction is proposed. Mesh generation for image tessellation, an error analysis, and performance results are presented. It is shown that distortion correction using commodity graphics hardware is substantially faster than using the main processor and can be performed at video frame rates (faster than 30 frames per second), and that the polar-based method of mesh generation proposed here is more accurate than a conventional grid-based approach. Using graphics hardware to perform distortion correction is not only fast and accurate but also efficient as it frees the main processor for other tasks, which is an important issue in some real-time applications.

  20. Detection of architectural distortion in mammograms using phase portraits

    Science.gov (United States)

    Ayres, Fabio J.; Rangayyan, Rangaraj M.

    2004-05-01

    Architectural distortion is a subtle abnormality in mammograms, and a source of overlooking errors by radiologists. Computer-aided diagnosis (CAD) techniques can improve the performance of radiologists in detecting masses and calcifications; however, most CAD systems have not been designed to detect architectural distortion. We present a new method to detect and localize architectural distortion by analyzing the oriented texture in mammograms. A bank of Gabor filters is used to obtain the orientation field of the given mammogram. The orientation field is filtered and downsampled, to reduce noise and also to reduce the computational effort required by the subsequent methods. The downsampled orientation field is analyzed to produce three phase portrait maps: node, saddle, and spiral. The node map is linearly filtered, thresholded, and morphologically filtered to detect architectural distortion. The method was tested with 18 mammograms containing architectural distortion. In a preliminary experiment, a sensitivity of 88% was obtained at 15 false positives per image. Several possibilities for the improvement of the technique are being explored. A qualitative analysis of the performance of the method with stellate lesions indicates potential for enhancement of the technique.

  1. Development, comparison, and evaluation of software for radial distortion elimination

    Science.gov (United States)

    Papadaki, A. I.; Georgopoulos, A.

    2015-05-01

    Lately the interest of Computer Vision and Photogrammetry community has been focused on the automation of the processes of identification and elimination of the radial distortion, with the aim to correct the image coordinates and finally to obtain digital images with reliable geometric information. This effort has reached the point of development of commercial or free image processing software, claiming that it can automatically identify and remove the radial distortion from an image. In this paper in depth research has been conducted about the radial distortion and the methods of its identification and elimination. Specifically, it has been attempted to evaluate software as the aforementioned, about its effectiveness, accuracy and applicability on the elimination of the radial distortion from images. For the attainment of the desired aim, four different methods of comparison and evaluation of the performance of the software, with respect to the correction of an image, have been employed. The applied methods are (i) the optical evaluation of the produced digital images, (ii) the subtraction of the images, (iii) the comparison of the curves of the remaining radial distortion in the images and (iv) the comparison of the results from the orientation of an image pair. However, it was really important to have a benchmark for the evaluation, in order to ensure the objectivity and accuracy of the comparison. Therefore, a new reliable algorithm has been developed, which was of known and controllable accuracy. The results of these comparisons are presented and evaluated for their reliability and usefulness.

  2. Working memory and the memory distortion component of hindsight bias.

    Science.gov (United States)

    Calvillo, Dustin P

    2012-01-01

    One component of hindsight bias is memory distortion: Individuals' recollections of their predictions are biased towards known outcomes. The present study examined the role of working memory in the memory distortion component of hindsight bias. Participants answered almanac-like questions, completed a measure of working memory capacity, were provided with the correct answers, and attempted to recollect their original judgements in two conditions: with and without a concurrent working memory load. Participants' recalled judgements were more biased by feedback when they recalled these judgements with a concurrent memory load and working memory capacity was negatively correlated with memory distortion. These findings are consistent with reconstruction accounts of the memory distortion component of hindsight bias and, more generally, with dual process theories of cognition. These results also relate the memory distortion component of hindsight bias with other cognitive errors, such as source monitoring errors, the belief bias in syllogistic reasoning and anchoring effects. Implications for the separate components view of hindsight bias are discussed.

  3. Microwave radiometry and applications

    Science.gov (United States)

    Polívka, Jiří

    1995-09-01

    The radiometry in general is a method of detecting the radiation of matter. All material bodies and substances radiate energy in the form of electromagnetic waves according to Planck s Law. The frequency spectrum of such thermal radiation is determined, beyond the properties of a blackbody, by the emissivity of surfaces and by the temperature of a particular body. Also, its reflectivity and dispersion take part. Investigating the intensity of radiation and its spectral distribution, one may determine the temperature and characterize the radiating body as well as the ambient medium, all independently of distance. With the above possibilities, the radiometry represents a base of scientific method called remote sensing. Utilizing various models, temperature of distant bodies and images of observed scenes can be determined from the spatial distribution of radiation. In this method, two parameters are of paramount importance: the temperature resolution, which flows out from the detected energy, and the spatial resolution (or, angular resolution), which depends upon antenna size with respect to wavelength. An instrument usable to conduct radiometric observations thus consists of two basic elements: a detector or radiometer, which determines the temperature resolution, and an antenna which determines the angular or spatial resolution. For example, a photographic camera consists of an objective lens (antenna) and of a sensitive element (a film or a CCD). In remote sensing, different lenses and reflectors and different sensors are employed, both adjusted to a particular spectrum region in which certain important features of observed bodies and scenes are present: frequently, UV and IR bands are used. The microwave radiometry utilizes various types of antennas and detectors and provides some advantages in observing various scenes: the temperature resolution is recently being given in milikelvins, while the range extends from zero to millions of Kelvins. Microwaves also offer

  4. Microwave Radiometry in Remote Sensing

    DEFF Research Database (Denmark)

    Gudmandsen, Preben

    1982-01-01

    Microwave radiometry has shown its capabilities of observing and monitoring large-scale geophysical observables from space. Examples are sea surface temperature and surface wind over the ocean, sea ice extent, concentration and category and snow cover extent and water content. At low microwave...... frequencies the atmosphere is virtually transparent even with clouds which make microwave radiometry very valuable in regions with frequent cloud cover such as the temperate and arctic zones. At high frequencies, however, atmospheric absorption will degrade measurements of earth surfaces but this phenomenon...

  5. Microwave mixer technology and applications

    CERN Document Server

    Henderson, Bert

    2013-01-01

    Although microwave mixers play a critical role in wireless communication and other microwave applications employing frequency conversion circuits, engineers find that most books on this subject emphasize theoretical aspects, rather than practical applications. That's about to change with the forthcoming release of Microwave Mixer Technology and Applications. Based on a review of over one thousand patents on mixers and frequency conversion, authors Bert Henderson and Edmar Camargo have written a comprehensive book for mixer designers who want solid ideas for solving their own design challenges.

  6. Microwave Plasma Synthesis of Nanopowders

    Institute of Scientific and Technical Information of China (English)

    Joseph; Lik; Hang; Chau

    2007-01-01

    1 Results and Discussion Nanopowders were synthesized by using microwave plasma synthesis technique.The microwave plasma was operated in atmospheric pressure at a frequency of 2.45 GHz.The reaction temperature is directly related to the power of the microwave generator that can be controlled by adjusting the actual operating current.Firstly,ionization and dissociation of precursor species will be occurred in the plasma,nucleus can then be formed by the collision of these molecules,followed by the growth...

  7. Multiview Trajectory Mapping Using Homography with Lens Distortion Correction

    Directory of Open Access Journals (Sweden)

    Andrea Cavallaro

    2008-11-01

    Full Text Available We present a trajectory mapping algorithm for a distributed camera setting that is based on statistical homography estimation accounting for the distortion introduced by camera lenses. Unlike traditional approaches based on the direct linear transformation (DLT algorithm and singular value decomposition (SVD, the planar homography estimation is derived from renormalization. In addition to this, the algorithm explicitly introduces a correction parameter to account for the nonlinear radial lens distortion, thus improving the accuracy of the transformation. We demonstrate the proposed algorithm by generating mosaics of the observed scenes and by registering the spatial locations of moving objects (trajectories from multiple cameras on the mosaics. Moreover, we objectively compare the transformed trajectories with those obtained by SVD and least mean square (LMS methods on standard datasets and demonstrate the advantages of the renormalization and the lens distortion correction.

  8. Multiview Trajectory Mapping Using Homography with Lens Distortion Correction

    Directory of Open Access Journals (Sweden)

    Kayumbi Gabin

    2008-01-01

    Full Text Available Abstract We present a trajectory mapping algorithm for a distributed camera setting that is based on statistical homography estimation accounting for the distortion introduced by camera lenses. Unlike traditional approaches based on the direct linear transformation (DLT algorithm and singular value decomposition (SVD, the planar homography estimation is derived from renormalization. In addition to this, the algorithm explicitly introduces a correction parameter to account for the nonlinear radial lens distortion, thus improving the accuracy of the transformation. We demonstrate the proposed algorithm by generating mosaics of the observed scenes and by registering the spatial locations of moving objects (trajectories from multiple cameras on the mosaics. Moreover, we objectively compare the transformed trajectories with those obtained by SVD and least mean square (LMS methods on standard datasets and demonstrate the advantages of the renormalization and the lens distortion correction.

  9. The Observational Effects and Signatures of Tidally Distorted Solid Exoplanets

    CERN Document Server

    Saxena, Prabal; Summers, Michael

    2014-01-01

    Our work examines the detectability of tidally distorted solid exoplanets in synchronous rotation. Previous work has shown that tidally distorted shapes of close-in gas giants can give rise to radius underestimates and subsequently density overestimates for those planets. We examine the assumption that such an effect is too minimal for rocky exoplanets and find that for smaller M Class stars there may be an observationally significant tidal distortion effect at very close-in orbits. We quantify the effect for different stellar types and planetary properties using some basic assumptions. Finally, we develop a simple analytic expression to test if there are detectable bulge signatures in the photometry of a system. We find that close in for smaller M Class stars there may be an observationally significant signature that may manifest itself in both in-transit bulge signatures and ellipsoidal variations.

  10. Distributed Remote Vector Gaussian Source Coding with Covariance Distortion Constraints

    DEFF Research Database (Denmark)

    Zahedi, Adel; Østergaard, Jan; Jensen, Søren Holdt

    2014-01-01

    In this paper, we consider a distributed remote source coding problem, where a sequence of observations of source vectors is available at the encoder. The problem is to specify the optimal rate for encoding the observations subject to a covariance matrix distortion constraint and in the presence...... of side information at the decoder. For this problem, we derive lower and upper bounds on the rate-distortion function (RDF) for the Gaussian case, which in general do not coincide. We then provide some cases, where the RDF can be derived exactly. We also show that previous results on specific instances...... of this problem can be generalized using our results. We finally show that if the distortion measure is the mean squared error, or if it is replaced by a certain mutual information constraint, the optimal rate can be derived from our main result....

  11. Pulsar Pair Cascades in a Distorted Magnetic Dipole Field

    CERN Document Server

    Harding, Alice K

    2010-01-01

    We investigate the effect of a distorted neutron star dipole magnetic field on pulsar pair cascade multiplicity and pair death lines. Using a simple model for a distorted dipole field that produces an offset polar cap, we derive the accelerating electric field above the polar cap in space charge limited flow. We find that even a modest azimuthally asymmetric distortion can significantly increase the accelerating electric field on one side of the polar cap and, combined with a smaller field line radius of curvature, leads to larger pair multiplicity. The death line for producing pairs by curvature radiation moves downward in the P-Pdot diagram, allowing high pair multiplicities in a larger percentage of the radio pulsar population. These results could have important implications for the radio pulsar population, high energy pulsed emission and the pulsar contribution to cosmic ray positrons.

  12. Metering error quantification under voltage and current waveform distortion

    Science.gov (United States)

    Wang, Tao; Wang, Jia; Xie, Zhi; Zhang, Ran

    2017-09-01

    With integration of more and more renewable energies and distortion loads into power grid, the voltage and current waveform distortion results in metering error in the smart meters. Because of the negative effects on the metering accuracy and fairness, it is an important subject to study energy metering combined error. In this paper, after the comparing between metering theoretical value and real recorded value under different meter modes for linear and nonlinear loads, a quantification method of metering mode error is proposed under waveform distortion. Based on the metering and time-division multiplier principles, a quantification method of metering accuracy error is proposed also. Analyzing the mode error and accuracy error, a comprehensive error analysis method is presented which is suitable for new energy and nonlinear loads. The proposed method has been proved by simulation.

  13. Direct Determination of Expansion History Using Redshift Distortions

    CERN Document Server

    Song, Yong-Seon

    2012-01-01

    We investigate direct determination of expansion history using redshift distortions without plugging into detailed cosmological parameters. The observed spectra in redshift space include a mixture of information: fluctuations of density-density and velocity-velocity spectra, and distance measures of perpendicular and parallel components to the line of sight. Unfortunately it is hard to measure all the components simultaneously without any specific prior assumption. Common prior assumptions include a linear/quasi-linear model of redshift distortions or a model for the shape of the power spectra, which eventually breaks down on small scales at later epochs where nonlinear structure formation disturbs coherent growth. The degeneracy breaking between the effect of cosmic distances and redshift distortions for example depends on the prior we assume. As an alternative approach is to utilize the cosmological principle inscribed in the heart of the Friedmann-Lema\\^itre-Robertson-Walker (hereafter FLRW) universe, that...

  14. Source Coding in Networks with Covariance Distortion Constraints

    DEFF Research Database (Denmark)

    Zahedi, Adel; Østergaard, Jan; Jensen, Søren Holdt

    2016-01-01

    -distortion function (RDF). We then study the special cases and applications of this result. We show that two well-studied source coding problems, i.e. remote vector Gaussian Wyner-Ziv problems with mean-squared error and mutual information constraints are in fact special cases of our results. Finally, we apply our......We consider a source coding problem with a network scenario in mind, and formulate it as a remote vector Gaussian Wyner-Ziv problem under covariance matrix distortions. We define a notion of minimum for two positive-definite matrices based on which we derive an explicit formula for the rate...... results to a joint source coding and denoising problem. We consider a network with a centralized topology and a given weighted sum-rate constraint, where the received signals at the center are to be fused to maximize the output SNR while enforcing no linear distortion. We show that one can design...

  15. Rise-Time Distortion of Signal without Carrying Signal

    Science.gov (United States)

    Bukhman, N. S.

    2016-08-01

    The article deals with one-dimensional problem of rise-time distortion signal without carrying signal, that appears in the starting point intermittently, that is signal distortion at front edge or one of its derivative. The authors show that front edge of signal isn't distorted in case of propagation in unrestricted (including absorbing) area (amplitude of starting signal step or of one of its derivatives doesn't change) and move with the accuracy of vacuum light speed. The paper proves that it is the time interval shortage that causes signal loss with the route extension, but not the reduction of its starting amplitude, during which front edge of signal retains its starting value. The research presents new values for this time interval.

  16. Modeling Distortion Effects in Class-D Amplifier Filter Inductors

    DEFF Research Database (Denmark)

    Knott, Arnold; Stegenborg-Andersen, Tore; Thomsen, Ole Cornelius

    2010-01-01

    Distortion is generally accepted as a quantifier to judge the quality of audio power amplifiers. In switchmode power amplifiers various mechanisms influence this performance measure. After giving an overview of those, this paper focuses on the particular effect of the nonlinearity of the output...... filter components on the audio performance. While the physical reasons for both, the capacitor and the inductor induced distortion are given, the practical in depth demonstration is done for the inductor only. This includes measuring the inductors performance, modeling through fitting and resulting...... into simulation models. The fitted models achieve distortion values between 0.03 % and 0.2 % as a basis to enable the design of a 200 W amplifier....

  17. Word Recognition for Temporally and Spectrally Distorted Materials

    DEFF Research Database (Denmark)

    Smith, Sherri L.; Pichora-Fuller, Margaret Kathleen; Wilson, Richard H.

    2012-01-01

    Objectives: The purpose of Experiment 1 was to measure word recognition in younger adults with normal hearing when speech or babble was temporally or spectrally distorted. In Experiment 2, older listeners with near-normal hearing and with hearing loss (for pure tones) were tested to evaluate...... their susceptibility to changes in speech level and distortion types. The results across groups and listening conditions were compared to assess the extent to which the effects of the distortions on word recognition resembled the effects of age-related differences in auditory processing or pure-tone hearing loss...... were evaluated in four conditions using the Words-in-Noise test in combinations of unaltered or jittered speech and unaltered or jittered babble. In Experiment 2, word recognition in quiet and in babble was measured in 72 older adults with near-normal hearing and 72 older adults with hearing loss...

  18. Monolithically Integrated Reconfigurable Filters for Microwave Photonic Links

    Science.gov (United States)

    Norberg, Erik J.

    optical amplifiers (SOAs) with low distortion and noise. Utilizing a novel characterization method of RF signal distortion for photonic devices, SOAs with state-of-the art SFDR in the range of 115 dB--Hz2/3 and a noise figure of 3.8 dB for 6 dB gain, is demonstrated. It is projected that this platform could ultimately provide integration for photonic microwave filter applications.

  19. Microwave Magnetoelectric Devices

    Directory of Open Access Journals (Sweden)

    A. S. Tatarenko

    2012-01-01

    Full Text Available Tunable microwave magnetoelectric devices based on layered ferrite-ferroelectric structures are described. The theory and experiment for attenuator, band-pass filter and phase shifter are presented. Tunability of the ME devices characteristics can be executed by application of an electric field. This electric tuning is relatively fast and is not power-consuming. The attenuator insertion losses vary from 26 dB to 2 dB at frequency 7251 MHz. The tuning range of 25 MHz of band-pass filter at frequency 7360 MHz was obtained. A maximum phase shift of 30–40 degree at the frequency region 6–9 GHz was obtained.

  20. Cryogenic coaxial microwave filters

    CERN Document Server

    Tancredi, G; Meeson, P J

    2014-01-01

    At millikelvin temperatures the careful filtering of electromagnetic radiation, especially in the microwave regime, is critical for controlling the electromagnetic environment for experiments in fields such as solid-state quantum information processing and quantum metrology. We present a design for a filter consisting of small diameter dissipative coaxial cables that is straightforward to construct and provides a quantitatively predictable attenuation spectrum. We describe the fabrication process and demonstrate that the performance of the filters is in good agreement with theoretical modelling. We further perform an indicative test of the performance of the filters by making current-voltage measurements of small, underdamped Josephson Junctions at 15 mK and we present the results.

  1. Critical Assessment of Correction Methods for Fisheye Lens Distortion

    Science.gov (United States)

    Liu, Y.; Tian, C.; Huang, Y.

    2016-06-01

    A fisheye lens is widely used to create a wide panoramic or hemispherical image. It is an ultra wide-angle lens that produces strong visual distortion. The distortion modeling and estimation of the fisheye lens are the crucial step for fisheye lens calibration and image rectification in computer vision and close-range photography. There are two kinds of distortion: radial and tangential distortion. Radial distortion is large for fisheye imaging and critical for the subsequent image processing. Although many researchers have developed calibration algorithms of radial distortion of fisheye lens, quantitative evaluation of the correction performance has remained a challenge. This is the first paper that intuitively and objectively evaluates the performance of five different calibration algorithms. Upto- date research on fisheye lens calibration is comprehensively reviewed to identify the research need. To differentiate their performance in terms of precision and ease-using, five methods are then tested using a diverse set of actual images of the checkerboard that are taken at Wuhan University, China under varying lighting conditions, shadows, and shooting angles. The method of rational function model, which was generally used for wide-angle lens correction, outperforms the other methods. However, the one parameter division model is easy for practical use without compromising too much the precision. The reason is that it depends on the linear structure in the image and requires no preceding calibration. It is a tradeoff between correction precision and ease-using. By critically assessing the strengths and limitations of the existing algorithms, the paper provides valuable insight and guideline for future practice and algorithm development that are important for fisheye lens calibration. It is promising for the optimal design of lens correction models that are suitable for the millions of portable imaging devices.

  2. Cosmic microwave background theory.

    Science.gov (United States)

    Bond, J R

    1998-01-06

    A long-standing goal of theorists has been to constrain cosmological parameters that define the structure formation theory from cosmic microwave background (CMB) anisotropy experiments and large-scale structure (LSS) observations. The status and future promise of this enterprise is described. Current band-powers in -space are consistent with a DeltaT flat in frequency and broadly follow inflation-based expectations. That the levels are approximately (10(-5))2 provides strong support for the gravitational instability theory, while the Far Infrared Absolute Spectrophotometer (FIRAS) constraints on energy injection rule out cosmic explosions as a dominant source of LSS. Band-powers at 100 suggest that the universe could not have re-ionized too early. To get the LSS of Cosmic Background Explorer (COBE)-normalized fluctuations right provides encouraging support that the initial fluctuation spectrum was not far off the scale invariant form that inflation models prefer: e.g., for tilted Lambda cold dark matter sequences of fixed 13-Gyr age (with the Hubble constant H0 marginalized), ns = 1.17 +/- 0.3 for Differential Microwave Radiometer (DMR) only; 1.15 +/- 0.08 for DMR plus the SK95 experiment; 1.00 +/- 0.04 for DMR plus all smaller angle experiments; 1.00 +/- 0.05 when LSS constraints are included as well. The CMB alone currently gives weak constraints on Lambda and moderate constraints on Omegatot, but theoretical forecasts of future long duration balloon and satellite experiments are shown which predict percent-level accuracy among a large fraction of the 10+ parameters characterizing the cosmic structure formation theory, at least if it is an inflation variant.

  3. Fast microwave assisted pyrolysis of biomass using microwave absorbent.

    Science.gov (United States)

    Borges, Fernanda Cabral; Du, Zhenyi; Xie, Qinglong; Trierweiler, Jorge Otávio; Cheng, Yanling; Wan, Yiqin; Liu, Yuhuan; Zhu, Rongbi; Lin, Xiangyang; Chen, Paul; Ruan, Roger

    2014-03-01

    A novel concept of fast microwave assisted pyrolysis (fMAP) in the presence of microwave absorbents was presented and examined. Wood sawdust and corn stover were pyrolyzed by means of microwave heating and silicon carbide (SiC) as microwave absorbent. The bio-oil was characterized, and the effects of temperature, feedstock loading, particle sizes, and vacuum degree were analyzed. For wood sawdust, a temperature of 480°C, 50 grit SiC, with 2g/min of biomass feeding, were the optimal conditions, with a maximum bio-oil yield of 65 wt.%. For corn stover, temperatures ranging from 490°C to 560°C, biomass particle sizes from 0.9mm to 1.9mm, and vacuum degree lower than 100mmHg obtained a maximum bio-oil yield of 64 wt.%. This study shows that the use of microwave absorbents for fMAP is feasible and a promising technology to improve the practical values and commercial application outlook of microwave based pyrolysis.

  4. Frequency Dependent PD-pulse Distortion in Rotating Machines

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Henriksen, Mogens

    1996-01-01

    In this contribution, the authors present results from investigations on the distortion of PD pulses in the stator winding of a 10 kV asynchronous motor. In order to determine the distortion of PD pulses from different, well defined parts in the winding, the following two techniques were used...... of the current transformer based detection method, when being applied to rotating machines. The results are discussed with regard to the practical application of PD detection systems on rotating machines, particularly considering aspects of range and applicability of systems in the HF ranges...

  5. Contrast distortion induced by modulation voltage in scanning capacitance microscopy

    Science.gov (United States)

    Chang, M. N.; Hu, C. W.; Chou, T. H.; Lee, Y. J.

    2012-08-01

    With a dark-mode scanning capacitance microscopy (SCM), we directly observed the influence of SCM modulation voltage (MV) on image contrasts. For electrical junctions, an extensive modulated area induced by MV may lead to noticeable changes in the SCM signal phase and intensity, resulting in a narrowed junction image and a broadened carrier concentration profile. This contrast distortion in SCM images may occur even if the peak-to-peak MV is down to 0.3 V. In addition, MV may shift the measured electrical junction depth. The balance of SCM signals components explain these MV-induced contrast distortions.

  6. Temperature and distortion transients in gas tungsten-arc weldments

    Energy Technology Data Exchange (ETDEWEB)

    Glickstein, S.S.; Friedman, E.

    1979-10-01

    An analysis and test program to develop a fundamental understanding of the gas tungsten-arc welding process has been undertaken at the Bettis Atomic Power Laboratory to develop techniques to determine and control the various welding parameters and weldment conditions so as to result in optimum weld response characteristics. These response characteristics include depth of penetration, weld bead configuration, weld bead sink and roll, distortion, and cracking sensitivity. The results are documented of that part of the program devoted to analytical and experimental investigations of temperatures, weld bead dimensions, and distortions for moving gas tungsten-arc welds applied to Alloy 600 plates.

  7. Visual distortions near a neutron star and black hole

    CERN Document Server

    Nemiroff, R J

    1993-01-01

    The visual distortion effects visible to an observer traveling around and descending to the surface of an extremely compact star are described. Specifically, trips to a "normal" neutron star, a black hole, and an ultracompact neutron star with extremely high surface gravity, are described. Concepts such as multiple imaging, red- and blue-shifting, conservation of surface brightness, the photon sphere, and the existence of multiple Einstein rings are discussed in terms of what the viewer would see. Computer generated, general relativistically accurate illustrations highlighting the distortion effects are presented and discussed. A short movie (VHS) depicting many of these effects is available to those interested free of charge.

  8. A channel distortion model for video over lossy packet networks

    Institute of Scientific and Technical Information of China (English)

    CHENG Jian-xin; GAO Zhen-ming; ZHANG Zhi-chao

    2006-01-01

    Error-resilient video communication over lossy packet networks is often designed and operated based on models for the effect of losses on the reconstructed video quality. This paper analyzes the channel distortion for video over lossy packet networks and proposes a new model that, compared to previous models, more accurately estimates the expected mean-squared error distortion for different packet loss patterns by accounting for inter-frame error propagation and the correlation between error frames. The accuracy of the proposed model is validated with JVT/H.264 encoded standard test sequences and previous frame concealment, where the proposed model provides an obvious accuracy gain over previous models.

  9. Information theory and rate distortion theory for communications and compression

    CERN Document Server

    Gibson, Jerry

    2013-01-01

    This book is very specifically targeted to problems in communications and compression by providing the fundamental principles and results in information theory and rate distortion theory for these applications and presenting methods that have proved and will prove useful in analyzing and designing real systems. The chapters contain treatments of entropy, mutual information, lossless source coding, channel capacity, and rate distortion theory; however, it is the selection, ordering, and presentation of the topics within these broad categories that is unique to this concise book. While the cover

  10. Privacy Preserving Categorical Data Analysis with Unknown Distortion Parameters

    Directory of Open Access Journals (Sweden)

    Ling Guo

    2009-12-01

    Full Text Available Randomized Response techniques have been investigated in privacy preserving categorical data analysis. However, the released distortion parameters can be exploited by attackers to breach privacy. In this paper, we investigate whether data mining or statistical analysis tasks can still be conducted on randomized data when distortion parameters are not disclosed to data miners. We first examine how various objective association measures between two variables may be affected by randomization. We then extend to multiple variables by examining the feasibility of hierarchical loglinear modeling. Finally we show some classic data mining tasks that cannot be applied on the randomized data directly.

  11. Naked singularities are not singular in distorted gravity

    Energy Technology Data Exchange (ETDEWEB)

    Garattini, Remo, E-mail: Remo.Garattini@unibg.it [Università degli Studi di Bergamo, Facoltà di Ingegneria, Viale Marconi 5, 24044 Dalmine (Bergamo) (Italy); I.N.F.N. – sezione di Milano, Milan (Italy); Majumder, Barun, E-mail: barunbasanta@iitgn.ac.in [Indian Institute of Technology Gandhinagar, Ahmedabad, Gujarat 382424 (India)

    2014-07-15

    We compute the Zero Point Energy (ZPE) induced by a naked singularity with the help of a reformulation of the Wheeler–DeWitt equation. A variational approach is used for the calculation with Gaussian Trial Wave Functionals. The one loop contribution of the graviton to the ZPE is extracted keeping under control the UltraViolet divergences by means of a distorted gravitational field. Two examples of distortion are taken under consideration: Gravity's Rainbow and Noncommutative Geometry. Surprisingly, we find that the ZPE is no more singular when we approach the singularity.

  12. Physical parameters activating electrical signal distortions in polluted soils

    Directory of Open Access Journals (Sweden)

    R. Angelini

    2002-06-01

    Full Text Available Laboratory investigations and field measurements show that the electrical behaviour of polluted soils is strongly non-linear at low frequencies. This phenomenon can be related to the class and the amount of pollutants. To measure this non-linearity, we used only monochromatic voltage waveform as input signal and analysed the current signals at first by means of the classical spectral analysis. In particular, the Total Harmonic Distortion % (THD% and the Harmonic Distortion %(? measure the non-linearity level and identify the frequency interval where the non-linear electrical behaviour is activated. This frequency interval can be related to the pollutant molecular size. Open interpretative problems were the following: 1 phase localization of the signal deformation; 2 «local» amplitude of the applied signal activating the distortion, and 3 numerical fit of the distortion. We employed the wavelet analysis to study the phenomenon. The wavelet technique breaks up a signal into shifted and scaled versions of the original wavelet, which is a waveform of limited duration. These features of the wavelets allow us to obtain current components that can be interpreted on the bases of a real physical meaning. By using the wavelet analysis, we obtained the phase localization of the ‘oscillations’ of the details and consequently the phase and amplitude of the applied signal. The sum of nine details provides a good numerical fit of the distorted signal. Starting from the wavelet analysis, we determined the physical conditions activating each distortion, testing some parameters on experimental data. The parameters that resulted most significant are the phase ? of the distortion activation and the product Vin?t (Vs (where ?t is the time interval corresponding to the said ? and Vin is the integral tension applied to the sample on ?t. The latter parameter is in a very good agreement with field data of Advanced Monochromatic Spectral Induced Polarization (AMSIP

  13. Identification and control of harmonic distortions report on Furnas experience

    Energy Technology Data Exchange (ETDEWEB)

    Mantuano Filho, Salvatore; Medeiros, Jose Roberto de; Bezerra, Luiz Roberto; Oliveira, Denise Borges de; Praca, Antonio Augusto Souza; Paiva Fontes, Marco Antonio de; Marques, Luiz Carlos Borges C. [FURNAS, Rio de Janeiro, RJ (Brazil)

    1994-12-31

    This paper describes FURNAS experience on identification and control of harmonic distortions obtained from conservation of system operation and research for solutions. Special attention is paid to the harmonic overload observed at Ibiuna substation, the receiving end of the FURNAS HVDC transmission of the Itaipu 50 Hz energy, and the solutions that have been adopted. Methods of measurement and digital simulation have been developed and successfully tested so far. The present stage of those methods will be described. Not less important is the need for a specific legislation on harmonic distortion as explained in this paper. (author) 6 refs., 2 figs.

  14. Digital image processing for the rectification of television camera distortions.

    Science.gov (United States)

    Rindfleisch, T. C.

    1971-01-01

    All television systems introduce distortions into the imagery they record which influence the results of quantitative photometric and geometric measurements. Digital computer techniques provide a powerful approach to the calibration and rectification of these systematic effects. Nonlinear as well as linear problems can be attacked with flexibility and precision. Methods which have been developed and applied for the removal of structured system noises and the correction of photometric, geometric, and resolution distortions in vidicon systems are briefly described. Examples are given of results derived primarily from the Mariner Mars 1969 television experiment.

  15. Analytical evaluation of nonlinear distortion effects on multicarrier signals

    CERN Document Server

    Araújo, Theresa

    2015-01-01

    Due to their ability to support reliable high quality of service as well as spectral and power efficiency, multicarrier modulation systems have found increasing use in modern communications services. However, one of the main drawbacks of these systems is their vulnerability to nonlinear distortion effects. Analytical Evaluation of Nonlinear Distortion Effects on Multicarrier Signals details a unified approach to well-known analytical results on memoryless nonlinearities that takes advantage of the Gaussian behavior of multicarrier signals.Sharing new insights into the behavior of nonlinearly d

  16. Develop Prototype Microwave Interferometry Diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Tringe, J. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Converse, M. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kane, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-11-15

    A prototype microwave interferometer was created at NSTec to characterize moving conductive fronts in upcoming experiments. The interferometer is capable of operation in the ~26-40 GHz band, and interrogating fronts with more than 1 W of power.

  17. Ordered mesoporous silica: microwave synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Fantini, M.C.A. [IF-USP, CP 66318, 05315-970, Sao Paulo, SP (Brazil)]. E-mail: mfantini@if.usp.br; Matos, J.R. [IQ-USP, CP 26077, 05599-970, Sao Paulo, SP (Brazil); Silva, L.C. Cides da [IQ-USP, CP 26077, 05599-970, Sao Paulo, SP (Brazil); Mercuri, L.P. [IQSC-USP, CP 780, 13560-970, Sao Carlos, SP (Brazil); Chiereci, G.O. [IQSC-USP, CP 780, 13560-970, Sao Carlos, SP (Brazil); Celer, E.B. [Department of Chemistry, Kent State University, Kent, OH 44240 (United States); Jaroniec, M. [Department of Chemistry, Kent State University, Kent, OH 44240 (United States)

    2004-09-25

    Ordered mesoporous silicas, FDU-1, synthesized by using triblock copolymer, EO{sub 39}BO{sub 47}EO{sub 39}, as template were hydrothermally treated in a microwave oven at 373 K for different periods of time. The structural and morphological properties of these silicas were investigated by X-ray diffraction and nitrogen adsorption and compared with those for the FDU-1 samples prepared by conventional hydrothermal treatment at 373 K. All samples were calcined at 813 K in N{sub 2} and air. This procedure succeeded in producing ordered cage-like mesoporous structures even after 15 min of the microwave treatment. The best sample was obtained after 60 min of the microwave treatment, which is reflected by narrow pore size distribution, uniform pore size entrances and thick mesopore walls. Longer time of the microwave treatment increased nonuniformity of the pore entrance sizes as evidenced by changes in the hysteresis loops of nitrogen adsorption isotherms.

  18. Microwave transistor oscillator frequency tripling

    OpenAIRE

    B. A. Kotserzhynskyi

    2010-01-01

    The frequency tripler state of the art is consided. The oscillator-frequency tripler design is now at the state of scientific research. Microwave companies release the devices of the such structure: oscillator, buffer, amplifier-tripler.

  19. Microwave transistor oscillator frequency tripling

    Directory of Open Access Journals (Sweden)

    B. A. Kotserzhynskyi

    2010-01-01

    Full Text Available The frequency tripler state of the art is consided. The oscillator-frequency tripler design is now at the state of scientific research. Microwave companies release the devices of the such structure: oscillator, buffer, amplifier-tripler.

  20. Wideband LTE power amplifier with integrated novel analog pre-distorter linearizer for mobile wireless communications.

    Science.gov (United States)

    Uthirajoo, Eswaran; Ramiah, Harikrishnan; Kanesan, Jeevan; Reza, Ahmed Wasif

    2014-01-01

    For the first time, a new circuit to extend the linear operation bandwidth of a LTE (Long Term Evolution) power amplifier, while delivering a high efficiency is implemented in less than 1 mm2 chip area. The 950 µm × 900 µm monolithic microwave integrated circuit (MMIC) power amplifier (PA) is fabricated in a 2 µm InGaP/GaAs process. An on-chip analog pre-distorter (APD) is designed to improve the linearity of the PA, up to 20 MHz channel bandwidth. Intended for 1.95 GHz Band 1 LTE application, the PA satisfies adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM) specifications for a wide LTE channel bandwidth of 20 MHz at a linear output power of 28 dBm with corresponding power added efficiency (PAE) of 52.3%. With a respective input and output return loss of 30 dB and 14 dB, the PA's power gain is measured to be 32.5 dB while exhibiting an unconditional stability characteristic from DC up to 5 GHz. The proposed APD technique serves to be a good solution to improve linearity of a PA without sacrificing other critical performance metrics.

  1. Cosmological constraints on interacting dark energy with redshift-space distortion after Planck data

    CERN Document Server

    Yang, Weiqiang

    2014-01-01

    The interacting dark energy model could propose a effective way to avoid the coincidence problem. In this paper, dark energy is taken as a fluid with a constant equation of state parameter $w_x$. In a general gauge, we could obtain two sets of different perturbation equations when the momentum transfer potential is vanished in the rest frame of dark matter or dark energy. There are many kinds of interacting forms from the phenomenological considerations, here, we choose $Q=3H\\xi_x\\rho_x$ which owns the stable perturbations in most cases. Then, according to the Markov Chain Monte Carlo method, we constrain the model by currently available cosmic observations which include cosmic microwave background radiation, baryon acoustic oscillation, type Ia supernovae, and $f\\sigma_8(z)$ data points from redshift-space distortion. Jointing the geometry tests with the large scale structure information, the results show a tighter constraint on the interacting model than the case without $f\\sigma_8(z)$ data. We find the int...

  2. Wideband LTE power amplifier with integrated novel analog pre-distorter linearizer for mobile wireless communications.

    Directory of Open Access Journals (Sweden)

    Eswaran Uthirajoo

    Full Text Available For the first time, a new circuit to extend the linear operation bandwidth of a LTE (Long Term Evolution power amplifier, while delivering a high efficiency is implemented in less than 1 mm2 chip area. The 950 µm × 900 µm monolithic microwave integrated circuit (MMIC power amplifier (PA is fabricated in a 2 µm InGaP/GaAs process. An on-chip analog pre-distorter (APD is designed to improve the linearity of the PA, up to 20 MHz channel bandwidth. Intended for 1.95 GHz Band 1 LTE application, the PA satisfies adjacent channel leakage ratio (ACLR and error vector magnitude (EVM specifications for a wide LTE channel bandwidth of 20 MHz at a linear output power of 28 dBm with corresponding power added efficiency (PAE of 52.3%. With a respective input and output return loss of 30 dB and 14 dB, the PA's power gain is measured to be 32.5 dB while exhibiting an unconditional stability characteristic from DC up to 5 GHz. The proposed APD technique serves to be a good solution to improve linearity of a PA without sacrificing other critical performance metrics.

  3. Distortion and Residual Stress Control in Integrally Stiffened Structure Produced by Direct Metal Deposition

    Science.gov (United States)

    Lin, Shih-Yung; Hoffman, Eric K.; Domack, Marcia S.

    2007-01-01

    2-D thermo-mechanical model developed to characterize distortion and residual stresses in integral structure produced by DMD. Demonstrated as a tool to guide experimental development of DMD fabrication process for aero structures. Distortion and residual stresses are local to deposit. Most distortion develops during deposition of the first few layers; Little change in distortion or residual stresses after fifth deposit layer Most of distortion is localized just beneath the build. Thicker build plates and the use of build lands results in greatest decrease in levels of distortion. Pre-straining shown to reduce distortion. Difficult to implement, particularly for complex stiffener arrays. Clamp position has complex effect on distortion and stresses. Overall distortion reduced with decreasing clamp clearance. Larger clamp clearances induce bending. Use of pre-heat and active cooling show minor influence on panel distortion. Generate changes in thermal gradients in the build plate.

  4. Microwave Ferrites for Cryogenic Applications

    OpenAIRE

    G. Dionne

    1997-01-01

    Recent advances in microwave ferrite device technology have seen the introduction of superconductivity that virtually eliminates insertion losses due to electrical conduction in microstrip circuits. The conventional ferrimagnetic spinel and garnet compositions, however, are not generally optimized for temperatures in the vicinity of 77 K and may require chemical redesign in order to realize the full potential of these devices. For microwave transmission, absorption losses may be reduced by a ...

  5. Microwave applications of soft ferrites

    CERN Document Server

    Pardavi-Horvath, M P

    2000-01-01

    Signal processing requires broadband, low-loss, low-cost microwave devices (circulators, isolators, phase shifters, absorbers). Soft ferrites (garnets, spinels, hexaferrites), applied in planar microwave devices, are reviewed from the point of view of device requirements. Magnetic properties, specific to operation in high-frequency electromagnetic fields, are discussed. Recent developments in thick film ferrite technology and device design are reviewed. Magnetic losses related to planar shape and inhomogeneous internal fields are analyzed.

  6. Microwave Drying of Moist Coals

    Science.gov (United States)

    Salomatov, Vl. V.; Karelin, V. A.; Sladkov, S. O.; Salomatov, Vas. V.

    2017-03-01

    Physical principles and examples of practical implementation of drying large bodies of coal by microwave radiation are considered. It is shown that energy consumption in microwave drying of brown coals decreases to 1.5-1.8 (kW·h)/ kg as compared with traditional types of drying, for which the expenditures of energy amount to 3.0 (kW·h)/kg. In using microwave drying, the technological time of drying decreases to 4 h, whereas the time of convective drying, with other things being equal, comes to 8-20 h. Parallel with microwave radiation drying, grinding of a fuel takes place, as well as entrainment of such toxic and ecologically harmful elements as mercury, chlorine, phosphorus, sulfur, and nitrogen. An analysis of the prospects of using a microwave energy for drying coal fuel has shown that microwave radiation makes it possible to considerably economize in energy, increase explosional safety, improve the ecological situation, and reduce the metal content and overall dimensions of the equipment.

  7. Study of federal microwave standards

    Energy Technology Data Exchange (ETDEWEB)

    David, L.

    1980-08-01

    Present and future federal regulatory processes which may impact the permissible levels of microwave radiation emitted by the SPS Microwave Power Transmission (MPTS) were studied. An historical development of US occupational and public microwave standards includes an overview of Western and East European philosophies of environmental protection and neurophysiology which have led to the current widely differing maximum permissible exposure limits to microwaves. The possible convergence of microwave standards is characterized by a lowering of Western exposure levels while Eastern countries consider standard relaxation. A trend toward stricter controls on activities perceived as harmful to public health is under way as is interest in improving the federal regulatory process. Particularly relevant to SPS is the initiation of long-term, low-level microwave exposure programs. Coupled with new developments in instrumentation and dosimetry, the results from chronic exposure program and population exposure studies could be expected within the next five to ten years. Also discussed is the increasing public concern that rf energy is yet another hazardous environmental agent.

  8. Cosmic Shear of the Microwave Background: The Curl Diagnostic

    CERN Document Server

    Cooray, A R; Caldwell, R R; Cooray, Asantha; Kamionkowski, Marc; Caldwell, Robert R.

    2005-01-01

    Weak-lensing distortions of the cosmic-microwave-background (CMB) temperature and polarization patterns can reveal important clues to the intervening large-scale structure. The effect of lensing is to deflect the primary temperature and polarization signal to slightly different locations on the sky. Deflections due to density fluctuations, gradient-type for the gradient of the projected gravitational potential, give a direct measure of the mass distribution. Curl-type deflections can be induced by, for example, a primordial background of gravitational waves from inflation or by second-order effects related to lensing by density perturbations. Whereas gradient-type deflections are expected to dominate, we show that curl-type deflections can provide a useful test of systematics and serve to indicate the presence of confusing secondary and foreground non-Gaussian signals.

  9. Systematic errors in cosmic microwave background polarization measurements

    CERN Document Server

    O'Dea, D; Johnson, B R; Dea, Daniel O'; Challinor, Anthony

    2006-01-01

    We investigate the impact of instrumental systematic errors on the potential of cosmic microwave background polarization experiments targeting primordial B-modes. To do so, we introduce spin-weighted Muller matrix-valued fields describing the linear response of the imperfect optical system and receiver, and give a careful discussion of the behaviour of the induced systematic effects under rotation of the instrument. We give the correspondence between the matrix components and known optical and receiver imperfections, and compare the likely performance of pseudo-correlation receivers and those that modulate the polarization with a half-wave plate. The latter is shown to have the significant advantage of not coupling the total intensity into polarization for perfect optics, but potential effects like optical distortions that may be introduced by the quasi-optical wave plate warrant further investigation. A fast method for tolerancing time-invariant systematic effects is presented, which propagates errors throug...

  10. Anisotropies in the microwave sky due to nonlinear structures

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Gonzalez, E.; Sanz, J.L.; Silk, J. (California Univ., Berkeley (USA))

    1990-05-01

    The propagation of light in a nonstatic linear gravitational potential associated with nonlinear density fluctuations is studied. A potential approximation to Einstein's field equations makes it possible to derive simple expressions for the anisotropies induced in the temperature of the microwave background radiation, associated in particular with angular distortions induced by the time-varying gravitational potential along the line of sight to the surface of last scattering. These results are applied to two examples of interest: a compensated void in the thin-shell approximation and a compensated lump in the Swiss cheese approach, obtaining the same results, with regard to temperature profiles, as those obtained using a general-relativistic treatment. 20 refs.

  11. Microwave background constraints on mixing of photons with hidden photons

    Energy Technology Data Exchange (ETDEWEB)

    Mirizzi, Alessandro [Max-Planck-Institut fuer Physik, Muenchen (Germany); Redondo, Javier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Sigl, Guenter [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2008-12-15

    Various extensions of the Standard Model predict the existence of hidden photons kinetically mixing with the ordinary photon. This mixing leads to oscillations between photons and hidden photons, analogous to the observed oscillations between different neutrino flavors. In this context, we derive new bounds on the photon-hidden photon mixing parameters using the high precision cosmic microwave background spectral data collected by the Far Infrared Absolute Spectrophotometer instrument on board of the Cosmic Background Explorer. Requiring the distortions of the CMB induced by the photon-hidden photon mixing to be smaller than experimental upper limits, this leads to a bound on the mixing angle {chi}{sub 0}

  12. Microwave spectroscopy of furfural in vibrationally excited states

    Science.gov (United States)

    Motiyenko, R. A.; Alekseev, E. A.; Dyubko, S. F.

    2007-07-01

    The results of microwave spectrum investigation of the excited vibrational states of furfural in the frequency range between 49 and 149 GHz are reported. In total 15 excited vibrational states (9 for trans-furfural and 6 for cis-furfural) were assigned and analyzed. Six of the 15 investigated states were assigned for the first time. Accurate values of rigid rotor and quartic centrifugal distortion constants of asymmetric top Hamiltonian have been determined for 13 excited states. Also for some states several sextic and octic level constants were needed in order to fit the data within experimental accuracy. The vt = 3 and vs = 1, va = 1 states of trans-furfural were found to be strongly perturbed and only rotational transitions with low Ka values can be reliably identified in this study.

  13. Controlled Microwave Heating Accelerates Rolling Circle Amplification.

    Science.gov (United States)

    Yoshimura, Takeo; Suzuki, Takamasa; Mineki, Shigeru; Ohuchi, Shokichi

    2015-01-01

    Rolling circle amplification (RCA) generates single-stranded DNAs or RNA, and the diverse applications of this isothermal technique range from the sensitive detection of nucleic acids to analysis of single nucleotide polymorphisms. Microwave chemistry is widely applied to increase reaction rate as well as product yield and purity. The objectives of the present research were to apply microwave heating to RCA and indicate factors that contribute to the microwave selective heating effect. The microwave reaction temperature was strictly controlled using a microwave applicator optimized for enzymatic-scale reactions. Here, we showed that microwave-assisted RCA reactions catalyzed by either of the four thermostable DNA polymerases were accelerated over 4-folds compared with conventional RCA. Furthermore, the temperatures of the individual buffer components were specifically influenced by microwave heating. We concluded that microwave heating accelerated isothermal RCA of DNA because of the differential heating mechanisms of microwaves on the temperatures of reaction components, although the overall reaction temperatures were the same.

  14. Alternative agricultural price distortions for CGE analysis, 2007 and 2011

    DEFF Research Database (Denmark)

    Jensen, Hans Grinsted; Anderson, Kym

    A recent World Bank research project has generated an annual time series of distortions to agricultural incentives over the past half century for 82 countries, the majority of which are low-and middle-income countries. In this memorandum, the current GTAP version 8 Data Base may be modified...

  15. Pathophysiological Distortions in Time Perception and Timed Performance

    Science.gov (United States)

    Allman, Melissa J.; Meck, Warren H.

    2012-01-01

    Distortions in time perception and timed performance are presented by a number of different neurological and psychiatric conditions (e.g. Parkinson's disease, schizophrenia, attention deficit hyperactivity disorder and autism). As a consequence, the primary focus of this review is on factors that define or produce systematic changes in the…

  16. Simulation on the Measurement Method of Geometric Distortion of Telescopes

    Science.gov (United States)

    Fan, Li; Shu-lin, Ren

    2016-07-01

    The accurate measurement on the effect of telescope geometric distortion is conducive to improving the astrometric positioning accuracy of telescopes, which is of significant importance for many disciplines of astronomy, such as stellar clusters, natural satellites, asteroids, comets, and other celestial bodies in the solar system. For this reason, the predecessors have developed an iterative self-calibration method to measure the telescope geometric distortion by dithering observations in a dense star field, and achieved fine results. However, the previous work did not make constraints on the density of star field, and the dithering mode, but chose empirically some good conditions (for example, a denser star field and a larger dithering number) to observe, which took up much observing time, and caused a rather low efficiency. In order to explore the validity of the self-calibration method, and optimize its observational conditions, it is necessary to carry out the corresponding simulations. In this paper, we introduce first the self-calibration method in detail, then by the simulation method, we verify the effectiveness of the self-calibration method, and make further optimizations on the observational conditions, such as the density of star field and the dithering number, to achieve a higher accuracy of geometric distortion measurement. Finally, taking consideration of the practical application for correcting the geometric distortion effect, we have analyzed the relationship between the number of reference stars in the field of view and the astrometric accuracy by virtue of the simulation method.

  17. Centration-distortion error: a criterion of perceptual dysfunction.

    Science.gov (United States)

    Mecke, V

    This was a study to determine whether centration, as a perceptual process, could be a criterion for differentiating between neurologically impaired and emotionally disturbed children. Centration was defined by Piaget as a prolonged involuntary attachment of a sensory modality to one part of a field, causing perceptual errors of exaggerations and distortions. It is hypothesized that centration would affect motor behavior, producing effects on drawing tasks characterized by separation of designs or their parts, coincident with distortions of the figures drawn. The neurologically impaired children were identified as having primary difficulties with perception whereas the emotionally disturbed children would have primary difficulties with intellection. The centration-distortion error would characterize the drawing of the neurologically impaired but not those of the emotionally disturbed children. A sample of 44 children was selected, each with EEG records, psychological tests and psychiatric interviews used as differential criteria for the groups. Eleven children were diagnosed as having minimal brain damage, 33 as emotionally disturbed. Three psychologists scored the Bender Gestalt tests, blind, for indicators of brain injury and emotional disturbance as defined by Koppitz' criteria, and for the centration-distortion error. The hypothesis was upheld at the .001 level of confidence, validating an earlier pilot study.

  18. An Accurate Projector Calibration Method Based on Polynomial Distortion Representation

    Directory of Open Access Journals (Sweden)

    Miao Liu

    2015-10-01

    Full Text Available In structure light measurement systems or 3D printing systems, the errors caused by optical distortion of a digital projector always affect the precision performance and cannot be ignored. Existing methods to calibrate the projection distortion rely on calibration plate and photogrammetry, so the calibration performance is largely affected by the quality of the plate and the imaging system. This paper proposes a new projector calibration approach that makes use of photodiodes to directly detect the light emitted from a digital projector. By analyzing the output sequence of the photoelectric module, the pixel coordinates can be accurately obtained by the curve fitting method. A polynomial distortion representation is employed to reduce the residuals of the traditional distortion representation model. Experimental results and performance evaluation show that the proposed calibration method is able to avoid most of the disadvantages in traditional methods and achieves a higher accuracy. This proposed method is also practically applicable to evaluate the geometric optical performance of other optical projection system.

  19. Computer Software for Displaying Map Projections and Comparing Distortions.

    Science.gov (United States)

    Wikle, Thomas

    1991-01-01

    Discusses software that educators can use to teach about distortions associated with alternative map projections. Examines the Projection, MicroCAM, World, and Atlas-GIS software programs. Suggests using the software in either introductory or more advanced courses dealing with map design or thematic cartography. Explains how to obtain the…

  20. A study on the structural distortion of the T` phase

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, W.; Vigoureux, P.; Andre, G.; Cousson, A.; Gukasov, A. [Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Braden, M. [Kernforschungszentrum Karlsruhe GmbH (Germany)]|[Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Adelman, P.; Schweiss, P. [Kernforschungszentrum Karlsruhe GmbH (Germany); Barilo, S.N.; Zhigounov, D.I. [AN Belorusskoj SSR, Minsk (Belarus); Heger, G. [Technische Hochschule Aachen (Germany). Lehrstuhl und Inst. fuer Kristallographie

    1994-12-31

    The structural deformation of the T` phase has been studied by means of neutron, x-ray and electron diffraction. A complete data collection of Bragg intensities on a single crystal of Gd{sub 2} CuO{sub 4} (GdCO) allows to determine the nature of the distorted phase. The oxygen squares surrounding the Cu-sites are rotated around the c-axis (by 5.2 degrees in GdCO at room temperature). The same structural distortion has also been observed in Nd{sub 0.38} Tb{sub 1.62} Cu O{sub 4} (NdTbCO) and in (Nd{sub 1-x} Tb{sub x}){sub 1.85} Ce{sub .15} CuO{sub 4} for x superior to 0.5. Therefore, one may conclude that the distortion results from a reduced average ionic radius of the RE. The phase diagram of Nd{sub 1.85-x} Tb{sub x} Ce{sub .15} CuO{sub 4} concerning superconductivity and the structural distortion has been examined. (authors). 5 refs., 2 figs.

  1. Distortion product otoacoustic emissions in the amphibian ear

    NARCIS (Netherlands)

    Van Dijk, Pim; Meenderink, Sebastiaan W. F.; Nuttal, AL

    2006-01-01

    By comparing the range of emission frequencies with that of neural characteristic frequencies of the amphibian and basilar papillae, the emission generation site may be inferred. Spontaneous otoacoustic emissions in the amphibian car seem to originate from the amphibian papilla. In contrast, distort

  2. PCA-Based Speech Enhancement for Distorted Speech Recognition

    Directory of Open Access Journals (Sweden)

    Tetsuya Takiguchi

    2007-09-01

    Full Text Available We investigated a robust speech feature extraction method using kernel PCA (Principal Component Analysis for distorted speech recognition. Kernel PCA has been suggested for various image processing tasks requiring an image model, such as denoising, where a noise-free image is constructed from a noisy input image. Much research for robust speech feature extraction has been done, but it remains difficult to completely remove additive or convolution noise (distortion. The most commonly used noise-removal techniques are based on the spectraldomain operation, and then for speech recognition, the MFCC (Mel Frequency Cepstral Coefficient is computed, where DCT (Discrete Cosine Transform is applied to the mel-scale filter bank output. This paper describes a new PCA-based speech enhancement algorithm using kernel PCA instead of DCT, where the main speech element is projected onto low-order features, while the noise or distortion element is projected onto high-order features. Its effectiveness is confirmed by word recognition experiments on distorted speech.

  3. Hierarchical Clustering and the Concept of Space Distortion.

    Science.gov (United States)

    Hubert, Lawrence; Schultz, James

    An empirical assesssment of the space distortion properties of two prototypic hierarchical clustering procedures is given in terms of an occupancy model developed from combinatorics. Using one simple example, the single-link and complete-link clustering strategies now in common use in the behavioral sciences are empirically shown to be space…

  4. Child molesters' cognitive distortions. Conceptualizations of the term.

    Science.gov (United States)

    Szumski, Filip; Zielona-Jenek, Monika

    2016-10-31

    The concept of cognitive distortion was created by A. T. Beck and it is one of the key-concepts of cognitive psychotherapy. In the 80s of the twentieth century, researchers began to use it in studies of sexual offending, but with reference to the social learning theory rather than to the theory of cognitive psychotherapy. Subsequent authors continued the use of this term in the determinants of child molestation and defined them as products emerging from specific implicit theory of the offender, the judgements resulting from his beliefs, values and actions, dysfunctional cognitive schemas, deviant cognitive practices undertaken in the interaction of internal and external components of perpetrator's cognitive system and his social practices. The primary theoretical background in the description of the concept of cognitive distortions of child molesters was the social cognition theory, but it was complemented with the assumptions of the theory of cognitive psychotherapy, extended theory of mind and discursive psychology perspective. Particular concepts describe the cognitive distortions relating them to different classes of cognitive phenomena: products, processes and structures, and the only thing they have in common is their incompatibility of their content to the social norms. Giving this concept a normative nature leads to internal contradictions within the conceptions that concern it. Moreover, using it to explain the various processes oversimplifies the picture of this phenomenon and leads to contradictions between theories. It is, therefore, necessary to consider replacing the term cognitive distortions with alternative and more precise concepts.

  5. Temperature dependence of anuran distortion product otoacoustic emissions

    NARCIS (Netherlands)

    Meenderink, Sebastlaan W. F.; Van Dijk, Pim

    To study the possible involvement of energy dependent mechanisms in the transduction of sound within the anuran ear, distortion product otoacoustic emissions (DPOAEs) were recorded in the northern leopard frog over a range of body temperatures. The effect of body temperature depended on the stimulus

  6. Spatial affects and imitations in OWS and Distortion

    DEFF Research Database (Denmark)

    Samson, Kristine

    the notions of affect (Thrift 2008, Ash & Amin 2002, Anderson & Holden 2008) and imitation (Tarde 1903), the paper will discuss recent urban crowd movements. OWS has spread a global social activist movement using affective bodily means of communication, whereas Distortion is a cultural street festival taking...

  7. Information Distortion in the Evaluation of a Single Option

    Science.gov (United States)

    Bond, Samuel D.; Carlson, Kurt A.; Meloy, Margaret G.; Russo, J. Edward; Tanner, Robin J.

    2007-01-01

    Extending previous work on biased predecisional processing, we investigate the distortion of information during the evaluation of a single option. A coherence-based account of the evaluation task suggests that individuals will form an initial assessment of favorability toward the option and then bias their evaluation of subsequent information to…

  8. Broadband distortion modeling in Lyman-$\\alpha$ forest BAO fitting

    CERN Document Server

    Blomqvist, Michael; Bautista, Julian E; Ariño, Andreu; Busca, Nicolás G; Miralda-Escudé, Jordi; Slosar, Anže; Font-Ribera, Andreu; Margala, Daniel; Schneider, Donald P; Vazquez, Jose A

    2015-01-01

    In recent years, the Lyman-$\\alpha$ absorption observed in the spectra of high-redshift quasars has been used as a tracer of large-scale structure by means of the three-dimensional Lyman-$\\alpha$ forest auto-correlation function at redshift $z\\simeq 2.3$, but the need to fit the quasar continuum in every absorption spectrum introduces a broadband distortion that is difficult to correct and causes a systematic error for measuring any broadband properties. We describe a $k$-space model for this broadband distortion based on a multiplicative correction to the power spectrum of the transmitted flux fraction that suppresses power on scales corresponding to the typical length of a Lyman-$\\alpha$ forest spectrum. Implementing the distortion model in fits for the baryon acoustic oscillation (BAO) peak position in the Lyman-$\\alpha$ forest auto-correlation, we find that the fitting method recovers the input values of the linear bias parameter $b_{F}$ and the redshift-space distortion parameter $\\beta_{F}$ for mock dat...

  9. Epipolar Rectification with Minimum Perspective Distortion for Oblique Images

    Science.gov (United States)

    Liu, Jianchen; Guo, Bingxuan; Jiang, Wanshou; Gong, Weishu; Xiao, Xiongwu

    2016-01-01

    Epipolar rectification is of great importance for 3D modeling by using UAV (Unmanned Aerial Vehicle) images; however, the existing methods seldom consider the perspective distortion relative to surface planes. Therefore, an algorithm for the rectification of oblique images is proposed and implemented in detail. The basic principle is to minimize the rectified images’ perspective distortion relative to the reference planes. First, this minimization problem is formulated as a cost function that is constructed by the tangent value of angle deformation; second, it provides a great deal of flexibility on using different reference planes, such as roofs and the façades of buildings, to generate rectified images. Furthermore, a reasonable scale is acquired according to the dihedral angle between the rectified image plane and the original image plane. The low-quality regions of oblique images are cropped out according to the distortion size. Experimental results revealed that the proposed rectification method can result in improved matching precision (Semi-global dense matching). The matching precision is increased by about 30% for roofs and increased by just 1% for façades, while the façades are not parallel to the baseline. In another designed experiment, the selected façades are parallel to the baseline, the matching precision has a great improvement for façades, by an average of 22%. This fully proves our proposed algorithm that elimination of perspective distortion on rectified images can significantly improve the accuracy of dense matching. PMID:27827991

  10. Distortion Estimation in Compressed Music Using Only Audio Fingerprints

    NARCIS (Netherlands)

    Doets, P.J.O.; Lagendijk, R.L.

    2008-01-01

    An audio fingerprint is a compact yet very robust representation of the perceptually relevant parts of an audio signal. It can be used for content-based audio identification, even when the audio is severely distorted. Audio compression changes the fingerprint slightly. We show that these small finge

  11. Correction of geometrically distorted underwater images using shift map analysis.

    Science.gov (United States)

    Halder, Kalyan Kumar; Paul, Manoranjan; Tahtali, Murat; Anavatti, Sreenatha G; Murshed, Manzur

    2017-04-01

    In underwater imaging, water waves cause severe geometric distortions and blurring of the acquired short-exposure images. Corrections for these distortions have been tackled reasonably well by previous efforts but still need improvement in the estimation of pixel shift maps to increase restoration accuracy. This paper presents a new algorithm that efficiently estimates the shift maps from geometrically distorted video sequences and uses those maps to restore the sequences. A nonrigid image registration method is employed to estimate the shift maps of the distorted frames against a reference frame. The sharpest frame of the sequence, determined using a sharpness metric, is chosen as the reference frame. A k-means clustering technique is employed to discard too-blurry frames that could result in inaccuracy in the shift maps' estimation. The estimated pixel shift maps are processed to generate the accurate shift map that is used to dewarp the input frames into their nondistorted forms. The proposed method is applied on several synthetic and real-world video sequences, and the obtained results exhibit significant improvements over the state-of-the-art methods.

  12. Modeling the Radio Foreground for Detection of CMB Spectral Distortions from the Cosmic Dawn and the Epoch of Reionization

    Science.gov (United States)

    Sathyanarayana Rao, Mayuri; Subrahmanyan, Ravi; Udaya Shankar, N.; Chluba, Jens

    2017-05-01

    Cosmic baryon evolution during the Cosmic Dawn and Reionization results in redshifted 21-cm spectral distortions in the cosmic microwave background (CMB). These encode information about the nature and timing of first sources over redshifts 30-6 and appear at meter wavelengths as a tiny CMB distortion along with the Galactic and extragalactic radio sky, which is orders of magnitude brighter. Therefore, detection requires precise methods to model foregrounds. We present a method of foreground fitting using maximally smooth (MS) functions. We demonstrate the usefulness of MS functions over traditionally used polynomials to separate foregrounds from the Epoch of Reionization (EoR) signal. We also examine the level of spectral complexity in plausible foregrounds using GMOSS, a physically motivated model of the radio sky, and find that they are indeed smooth and can be modeled by MS functions to levels sufficient to discern the vanilla model of the EoR signal. We show that MS functions are loss resistant and robustly preserve EoR signal strength and turning points in the residuals. Finally, we demonstrate that in using a well-calibrated spectral radiometer and modeling foregrounds with MS functions, the global EoR signal can be detected with a Bayesian approach with 90% confidence in 10 minutes’ integration.

  13. Factors associated with body image distortion in Korean adolescents

    Directory of Open Access Journals (Sweden)

    Hyun MY

    2014-05-01

    Full Text Available Mi-Yeul Hyun,1 Young-Eun Jung,2 Moon-Doo Kim,2 Young-Sook Kwak,2 Sung-Chul Hong,3 Won-Myong Bahk,4 Bo-Hyun Yoon,5 Hye Won Yoon,6 Bora Yoo61College of Nursing, Jeju National University, Jeju, Korea; 2Department of Psychiatry, School of Medicine, Jeju National University, Jeju, Korea; 3Department of Preventive Medicine, School of Medicine, Jeju National University, Jeju, Korea; 4Department of Psychiatry, Yeouido St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea; 5Department of Psychiatry, Naju National Hospital, Naju, Korea; 6School of Medicine, Jeju National University, Jeju, KoreaPurpose: Body image incorporates cognitive and affective components as well as behaviors related to own body perception. This study evaluated the occurrence of body image distortion and its correlates in Korean adolescents.Methods: In a school-based cross-sectional survey, a total of 2,117 adolescents were recruited. They filled out self-completing questionnaires on body image distortion, eating attitudes, and behaviors (Eating Attitude Test-26 and related factors.Results: Body image distortions were found in 51.8 percent of adolescents. Univariate analyses showed that boys and older adolescents had higher rates of body image distortion. In the multivariate analyses, body image distortion was associated with high risk for eating disorders (odds ratio [OR] =1.69; 95% confidence interval [CI] 1.11–2.58; P=0.015 and being over weight (OR =33.27; 95% CI 15.51–71.35; P<0.001 or obese (OR =9.37; 95% CI 5.06–17.34; P<0.001.Conclusion: These results suggest that body image distortion is relatively common in Korean adolescents, which has implications for adolescents at risk of developing eating disorders.Keywords: body image distortion, high risk for eating disorders, Korean adolescent

  14. Microwave Sterilization and Depyrogenation System

    Science.gov (United States)

    Akse, James R.; Dahl, Roger W.; Wheeler, Richard R., Jr.

    2009-01-01

    A fully functional, microgravity-compatible microwave sterilization and depyrogenation system (MSDS) prototype was developed that is capable of producing medical-grade water (MGW) without expendable supplies, using NASA potable water that currently is available aboard the International Space Station (ISS) and will be available for Lunar and planetary missions in the future. The microwave- based, continuous MSDS efficiently couples microwaves to a single-phase, pressurized, flowing water stream that is rapidly heated above 150 C. Under these conditions, water is rapidly sterilized. Endotoxins, significant biological toxins that originate from the cell walls of gram-negative bacteria and which represent another defining MGW requirement, are also deactivated (i.e., depyrogenated) albeit more slowly, with such deactivation representing a more difficult challenge than sterilization. Several innovations culminated in the successful MSDS prototype design. The most significant is the antenna-directed microwave heating of a water stream flowing through a microwave sterilization chamber (MSC). Novel antenna designs were developed to increase microwave transmission efficiency. These improvements resulted in greater than 95-percent absorption of incident microwaves. In addition, incorporation of recuperative heat exchangers (RHxs) in the design reduced the microwave power required to heat a water stream flowing at 15 mL/min to 170 C to only 50 W. Further improvements in energy efficiency involved the employment of a second antenna to redirect reflected microwaves back into the MSC, eliminating the need for a water load and simplifying MSDS design. A quick connect (QC) is another innovation that can be sterilized and depyrogenated at temperature, and then cooled using a unique flow design, allowing collection of MGW at atmospheric pressure and 80 C. The final innovation was the use of in-line mixers incorporated in the flow path to disrupt laminar flow and increase contact time

  15. The Assessment of Distortion in Neurosurgical Image Overlay Projection.

    Science.gov (United States)

    Vakharia, Nilesh N; Paraskevopoulos, Dimitris; Lang, Jozsef; Vakharia, Vejay N

    2016-02-01

    Numerous studies have demonstrated the superiority of neuronavigation during neurosurgical procedures compared to non-neuronavigation-based procedures. Limitations to neuronavigation systems include the need for the surgeons to avert their gaze from the surgical field and the cost of the systems, especially for hospitals in developing countries. Overlay projection of imaging directly onto the patient allows localization of intracranial structures. A previous study using overlay projection demonstrated the accuracy of image coregistration for a lesion in the temporal region but did not assess image distortion when projecting onto other anatomical locations. Our aim is to quantify this distortion and establish which regions of the skull would be most suitable for overlay projection. Using the difference in size of a square grid when projected onto an anatomically accurate model skull and a flat surface, from the same distance, we were able to calculate the degree of image distortion when projecting onto the skull from the anterior, posterior, superior, and lateral aspects. Measuring the size of a square when projected onto a flat surface from different distances allowed us to model change in lesion size when projecting a deep structure onto the skull surface. Using 2 mm as the upper limit for distortion, our results show that images can be accurately projected onto the majority (81.4%) of the surface of the skull. Our results support the use of image overlay projection in regions with ≤2 mm distortion to assist with localization of intracranial lesions at a fraction of the cost of existing methods. © The Author(s) 2015.

  16. Microwave assisted synthesis and characterization of unsymmetrical tetradentate Schiff base complexes of VO(IV) and MoO(V).

    Science.gov (United States)

    Thaker, B T; Barvalia, R S

    2011-12-15

    Microwave synthesis, is green chemical method, simple, sensitive, reducing solvent amount and reaction time. The attempt was made to synthesize the unsymmetrical tetradentate N(2)O(2) ligands and their VO(IV) and MoO(V) unsymmetrical tetradentate Schiff base complexes by classical and microwave techniques using domestic microwave oven. The resulting unsymmetrical Schiff base ligands L(1)-L(3) characterized by different spectral methods. Their complexes with oxocations of VO(IV) and MoO(V) have been synthesized and characterized by elemental analyses, conductometric measurements, infrared and electronic absorption, (1)H NMR spectra, mass spectrometry, ESR spectra, magnetic susceptibility measurement and thermal study. The study suggests that the oxo metal ion is bonded to the ligand through the oxygen and imino nitrogen and the geometry around metal ion is distorted octahedral.

  17. Imaging Techniques for Microwave Diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Donne, T. [FOM-Institute for Plasma Physics Rijnhuizen, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Luhmann Jr, N.C. [University of California, Davis, CA 95616 (United States); Park, H.K. [POSTECH, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Tobias, B.

    2011-07-01

    Advances in microwave technology have made it possible to develop a new generation of microwave imaging diagnostics for measuring the parameters of magnetic fusion devices. The most prominent of these diagnostics is electron cyclotron emission imaging (ECE-I). After the first generation of ECE-I diagnostics utilized at the TEXT-U, RTP and TEXTOR tokamaks and the LHD stellarator, new systems have recently come into operation on ASDEX-UG and DIII-D, soon to be followed by a system on KSTAR. The DIII-D and KSTAR systems feature dual imaging arrays that observe different parts of the plasma. The ECE-I diagnostic yields two-dimensional movies of the electron temperature in the plasma and has given already new insights into the physics of sawtooth oscillations, tearing modes and edge localized modes. Microwave Imaging Reflectometry (MIR) is used on LHD to measure electron density fluctuations. A pilot MIR system has been tested at TEXTOR and, based on the promising results, a new system is now under design for KSTAR. The system at TEXTOR was used to measure the plasma rotation velocity. The system at KSTAR and also the one on LHD will be/are used for measuring the profile of the electron density fluctuations in the plasma. Other microwave imaging diagnostics are phase imaging interferometry, and imaging microwave scattering. The emphasis in this paper will be largely focused on ECE-I. First an overview of the advances in microwave technology are discussed, followed by a description of a typical ECE-I system along with some typical experimental results. Also the utilization of imaging techniques in other types of microwave diagnostics will be briefly reviewed. This document is composed of the slides of the presentation. (authors)

  18. Microwave. Instructor's Edition. Louisiana Vocational-Technical Education.

    Science.gov (United States)

    Blanton, William

    This publication contains related study assignments and job sheets for a course in microwave technology. The course is organized into 12 units covering the following topics: introduction to microwave, microwave systems, microwave oscillators, microwave modulators, microwave transmission lines, transmission lines, detectors and mixers, microwave…

  19. Near-field scanning microwave microscopy of microwave devices

    Science.gov (United States)

    Vlahacos, C. P.; Steinhauer, David E.; Dutta, S.; Anlage, S. M.; Wellstood, F. C.; Newman, H.

    1997-03-01

    We have developed a scanning microwave microscope which can presently image features with a spatial resolution of 10-100 μm in the frequency range 5-15 GHz.(C. P. Vlahacos, et al.), Appl. Phys. Lett. 69, 3272 (1996).^,(S. M. Anlage, et al.), IEEE. Trans. Appl. Supercond. (1997). The microscope consists of a resonant section of a coaxial cable which is terminated with a small-diameter open-ended coaxial probe. Images are made by scanning the sample under the probe while recording the induced near-field microwave voltage as a function of sample position. We will present images for several microwave devices, including an X-band microstrip planar ferrite circulator and a high-temperature superconducting microstrip YBa_2Cu_3O_7-δ resonator, and compare them to the calculated field profiles.

  20. Microwave Radiometer for Aviation Safety Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SBIR Phase I Project proposes a new passive microwave airborne sensor for in flight icing hazard detection, Microwave Radiometer for Aviation Safety. A feasibility...

  1. Microwave Plasma System: PVA Tepla 300

    Data.gov (United States)

    Federal Laboratory Consortium — Description:CORAL Name: Microwave AsherA tool using microwave oxygen plasma to remove organics on the surfacesSpecifications / Capabilities:Frequency: 2.45 GHzPower:...

  2. Student Microwave Experiments Involving the Doppler Effect.

    Science.gov (United States)

    Weber, F. Neff; And Others

    1980-01-01

    Described is the use of the Doppler Effect with microwaves in the measurement of the acceleration due to gravity of falling objects. The experiments described add to the repertoire of quantitative student microwave experiments. (Author/DS)

  3. DMSP SSM/I- Microwave Imager

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/I is a seven-channel, four frequency, linearly-polarized, passive microwave radiometric system which measures atmospheric, ocean and terrain microwave...

  4. Mapping Microwave Fields With Thermal Paper

    Science.gov (United States)

    Watkins, John L.

    1992-01-01

    Simple, inexpensive technique used to map direction and intensity of electric field in microwave resonant cavity. Technique extension of using thermal paper to map intensities (only) of microwave fields.

  5. Digital microwave communication engineering point-to-point microwave systems

    CERN Document Server

    Kizer, George

    2013-01-01

    The first book to cover all engineering aspects of microwave communication path design for the digital age Fixed point-to-point microwave systems provide moderate-capacity digital transmission between well-defined locations. Most popular in situations where fiber optics or satellite communication is impractical, it is commonly used for cellular or PCS site interconnectivity where digital connectivity is needed but not economically available from other sources, and in private networks where reliability is most important. Until now, no book has adequately treated all en

  6. An experimental investigation of compressor stall using an on-line distortion indicator and signal conditioner

    Science.gov (United States)

    Costakis, W. G.; Wenzel, L. M.

    1975-01-01

    The relation of the steady-state and dynamic distortions and the stall margin of a J85-13 turbojet engine was investigated. A distortion indicator capable of computing two distortion indices was used. A special purpose signal conditioner was also used as an interface between transducer signals and distortion indicator. A good correlation of steady-state distortion and stall margin was established. The prediction of stall by using the indices as instantaneous distortion indicators was not successful. A sensitivity factor that related the loss of stall margin to the turbulence level was found.

  7. Fourier transform microwave and millimeter wave spectroscopy of quinazoline, quinoxaline, and phthalazine

    Science.gov (United States)

    McNaughton, Don; Godfrey, Peter D.; Jahn, Michaela K.; Dewald, David A.; Grabow, Jens-Uwe

    2011-04-01

    The pure rotational spectra of the bicyclic aromatic nitrogen heterocycle molecules, quinazoline, quinoxaline, and phthalazine, have been recorded and assigned in the region 13-87 GHz. An analysis, guided by ab initio molecular orbital predictions, of frequency-scanned Stark modulated, jet-cooled millimeter wave absorption spectra (48-87 GHz) yielded a preliminary set of rotational and centrifugal distortion constants. Subsequent spectral analysis at higher resolution was carried out with Fourier transform microwave (FT-MW) spectroscopy (13-18 GHz) of a supersonic rotationally cold molecular beam. The high spectral resolution of the FT-MW instrument provided an improved set of rotational and centrifugal distortion constants together with nitrogen quadrupole coupling constants for all three species. Density functional theory calculations at the B3LYP/6-311+G** level of theory closely predict rotational constants and are useful in predicting quadrupole coupling constants and dipole moments for such species.

  8. A subwavelength resolution microwave/6.3 GHz camera based on a metamaterial absorber.

    Science.gov (United States)

    Xie, Yunsong; Fan, Xin; Chen, Yunpeng; Wilson, Jeffrey D; Simons, Rainee N; Xiao, John Q

    2017-01-10

    The design, fabrication and characterization of a novel metamaterial absorber based camera with subwavelength spatial resolution are investigated. The proposed camera is featured with simple and lightweight design, easy portability, low cost, high resolution and sensitivity, and minimal image interference or distortion to the original field distribution. The imaging capability of the proposed camera was characterized in both near field and far field ranges. The experimental and simulated near field images both reveal that the camera produces qualitatively accurate images with negligible distortion to the original field distribution. The far field demonstration was done by coupling the designed camera with a microwave convex lens. The far field results further demonstrate that the camera can capture quantitatively accurate electromagnetic wave distribution in the diffraction limit. The proposed camera can be used in application such as non-destructive image and beam direction tracer.

  9. Microwave Semiconductor Equipment Produced in Poland,

    Science.gov (United States)

    1984-01-20

    lQal signal source in other devices. Microwave Transistors As a result of work in the field of microwave transistors , the technology for pnp ...is now commonly carried out on transistors and microwave subsystems. The results of the labors of the DM section connected with the new devices and...level of employment Illustration 2. Microwave diodes and semiconductor transistors presently produced in the ITE (DM section) The Construction and

  10. On Interactions of Microwave with Lightwave

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper addresses interactions of lightwave with microwave, and is divided into two parts. In part one, the background and the main topics of the research filed are introduced. In part two, some research activities at Shanghai University are reviewed.These include optical control of microwave devices, photoinduced electromagnetic radiation, lightwave interaction with superconductors, microwave control of lightwave, and the microwave approach to highly irregular fiber optics.

  11. Advances In Microwave Metamaterials

    Science.gov (United States)

    Wigle, James A.

    2011-12-01

    Metamaterials are a new area of research showing significant promise for an entirely new set of materials, and material properties. Only recently has three-fourths of the entire electromagnetic material space been made available for discoveries, research, and applications. This thesis is a culmination of microwave metamaterial research that has transpired over numerous years at the University of Colorado. New work is presented; some is complete while other work has yet to be finished. Given the significant work efforts, and potential for new and interesting results, I have included some of my partial work to be completed in the future. This thesis begins with background theory to assist readers in fully understanding the mechanisms that drove my research and results obtained. I illustrate the design and manufacture of a metamaterial that can operate within quadrants I and II of the electromagnetic material space (epsilon r > 0 and mur > 0 or epsilonr 0, respectively). Another metamaterial design is presented for operation within quadrant III of the electromagnetic material space (epsilonr thesis also presents two related, but different, novel tests intended to be used to definitively illustrate the negative angle of refraction for indices of refraction less than zero. It will be shown how these tests can be used to determine most bulk electromagnetic material properties of the material under test, for both right handed and left handed materials, such as epsilonr, mur, deltaloss, and n. The work concluding this thesis is an attempt to derive modified Fresnel Coefficients, for which I actually believe to be incorrect. Though, in transposing I have corrected a few mistakes, and now I can no longer find the conundrum. I have included this work to illuminate the need for modified Fresnel coefficients for cases of negative indices of refraction, identifying all disparate cases requiring a new set of equations, as well as to assist others in their efforts through

  12. 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 implemen...... carrier to a 9-GHz carrier with penalty-free transmission over 25 km of optical fiber. Finally, the transparent link transmits a standard FM video 7.6-GHz radio-link signal over 25 km of optical fiber without measurable distortion...... 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...

  13. Microwave Activation of Drug Release

    DEFF Research Database (Denmark)

    Jónasson, Sævar Þór

    Due to current limitations in control of pharmaceutical drug release in the body along with increasing medicine use, methods of externally-controlled drug release are of high interest. In this thesis, the use of microwaves is proposed as a technique with the purpose of externally activating...... setup, called the microwave activation system has been developed and tested on a body phantom that emulates the human torso. The system presented in this thesis, operates unobtrusively, i.e. without physically interfering with the target (patient). The torso phantom is a simple dual-layered cylindrical...... the phantom is of interest for disclosing essential information about the limitations of the concept, the phantom and the system. For these purposes, a twofold operation of the microwave activation system was performed, which are reciprocal of each other. In the first operation phase, named mapping...

  14. High power ferrite microwave switch

    Science.gov (United States)

    Bardash, I.; Roschak, N. K.

    1975-01-01

    A high power ferrite microwave switch was developed along with associated electronic driver circuits for operation in a spaceborne high power microwave transmitter in geostationary orbit. Three units were built and tested in a space environment to demonstrate conformance to the required performance characteristics. Each unit consisted of an input magic-tee hybrid, two non-reciprocal latching ferrite phase shifters, an out short-slot 3 db quadrature coupler, a dual driver electronic circuit, and input logic interface circuitry. The basic mode of operation of the high power ferrite microwave switch is identical to that of a four-port, differential phase shift, switchable circulator. By appropriately designing the phase shifters and electronic driver circuits to operate in the flux-transfer magnetization mode, power and temperature insensitive operation was achieved. A list of the realized characteristics of the developed units is given.

  15. Compact Microwave Fourier Spectrum Analyzer

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry

    2009-01-01

    A compact photonic microwave Fourier spectrum analyzer [a Fourier-transform microwave spectrometer, (FTMWS)] with no moving parts has been proposed for use in remote sensing of weak, natural microwave emissions from the surfaces and atmospheres of planets to enable remote analysis and determination of chemical composition and abundances of critical molecular constituents in space. The instrument is based on a Bessel beam (light modes with non-zero angular momenta) fiber-optic elements. It features low power consumption, low mass, and high resolution, without a need for any cryogenics, beyond what is achievable by the current state-of-the-art in space instruments. The instrument can also be used in a wide-band scatterometer mode in active radar systems.

  16. A distortional semi-discretized thin-walled beam element

    DEFF Research Database (Denmark)

    Andreassen, Michael Joachim; Jönsson, Jeppe

    2013-01-01

    Due to the increased consumption of thin-walled structural elements there has been increasing focus and need for more detailed calculations as well as development of new approaches. In this paper a thin-walled beam element including distortion of the cross section is formulated. The formulation...... is based on a generalized beam theory (GBT), in which the classic Vlasov beam theory for analysis of open and closed thin-walled cross sections is generalized by including distortional displacements. The beam element formulation utilizes a semi-discretization approach in which the cross section...... is discretized into wall elements and the analytical solutions of the related GBT beam equations are used as displacement functions in the axial direction. Thus the beam element contains the semi-analytical solutions. In three related papers the authors have recently presented the semi-discretization approach...

  17. Bayesian redshift-space distortions correction from galaxy redshift surveys

    CERN Document Server

    Kitaura, Francisco-Shu; Angulo, Raul E; Chuang, Chia-Hsun; Rodriguez-Torres, Sergio; Monteagudo, Carlos Hernandez; Prada, Francisco; Yepes, Gustavo

    2015-01-01

    We present a Bayesian reconstruction method which maps a galaxy distribution from redshift-space to real-space inferring the distances of the individual galaxies. The method is based on sampling density fields assuming a lognormal prior with a likelihood given by the negative binomial distribution function modelling stochastic bias. We assume a deterministic bias given by a power law relating the dark matter density field to the expected halo or galaxy field. Coherent redshift-space distortions are corrected in a Gibbs-sampling procedure by moving the galaxies from redshift-space to real-space according to the peculiar motions derived from the recovered density field using linear theory with the option to include tidal field corrections from second order Lagrangian perturbation theory. The virialised distortions are corrected by sampling candidate real-space positions (being in the neighbourhood of the observations along the line of sight), which are compatible with the bulk flow corrected redshift-space posi...

  18. Sweep Distortion Removal from THz Images via Blind Demodulation

    CERN Document Server

    Aghasi, Alireza; Redo-Sanchez, Albert; Romberg, Justin; Raskar, Ramesh

    2016-01-01

    Heavy sweep distortion induced by alignments and inter-reflections of layers of a sample is a major burden in recovering 2D and 3D information in time resolved spectral imaging. This problem cannot be addressed by conventional denoising and signal processing techniques as it heavily depends on the physics of the acquisition. Here we propose and implement an algorithmic framework based on low-rank matrix recovery and alternating minimization that exploits the forward model for THz acquisition. The method allows recovering the original signal in spite of the presence of temporal-spatial distortions. We address a blind-demodulation problem, where based on several observations of the sample texture modulated by an undesired sweep pattern, the two classes of signals are separated. The performance of the method is examined in both synthetic and experimental data, and the successful reconstructions are demonstrated. The proposed general scheme can be implemented to advance inspection and imaging applications in THz ...

  19. Adaptive EZW coding using a rate-distortion criterion

    Science.gov (United States)

    Yin, Che-Yi

    2001-07-01

    This work presents a new method that improves on the EZW image coding algorithm. The standard EZW image coder uses a uniform quantizer with a threshold (deadzone) that is identical in all subbands. The quantization step sizes are not optimized under the rate-distortion sense. We modify the EZW by applying the Lagrange multiplier to search for the best step size for each subband and allocate the bit rate for each subband accordingly. Then we implement the adaptive EZW codec to code the wavelet coefficients. Two coding environments, independent and dependent, are considered for the optimization process. The proposed image coder retains all the good features of the EZW, namely, embedded coding, progressive transmission, order of the important bits, and enhances it through the rate-distortion optimization with respect to the step sizes.

  20. Base Station Antenna Pattern Distortion in Practical Urban Deployment Scenarios

    DEFF Research Database (Denmark)

    Rodriguez Larrad, Ignacio; Nguyen, Huan Cong; Sørensen, Troels Bundgaard

    2014-01-01

    In real urban deployments, base station antennas are typically not placed in free space conditions. Therefore, the radiation pattern can be affected by mounting structures and nearby obstacles located in the proximity of the antenna (near-field), which are often not taken into consideration. Also...... the intrinsic propagation mechanisms of the urban environment (far-field) can contribute to the distortion of the radiation pattern observed in a practical deployment scenario, especially when comparing it to the antenna pattern provided by the manufacturer and typically measured in free space. This paper...... presents a combination of near-field and far-field simulations aimed to provide an overview of the distortion experienced by the base station antenna pattern in two different urban deployment scenarios: rooftop and telecommunications tower. The study illustrates how, in comparison with the near...

  1. High thermoelectric performance of the distorted bismuth(110) layer.

    Science.gov (United States)

    Cheng, L; Liu, H J; Zhang, J; Wei, J; Liang, J H; Jiang, P H; Fan, D D; Sun, L; Shi, J

    2016-07-14

    The thermoelectric properties of the distorted bismuth(110) layer are investigated using first-principles calculations combined with the Boltzmann transport equation for both electrons and phonons. To accurately predict the electronic and transport properties, the quasiparticle corrections with the GW approximation of many-body effects have been explicitly included. It is found that a maximum ZT value of 6.4 can be achieved for n-type systems, which essentially stemmed from the weak scattering of electrons. Moreover, we demonstrate that the distorted Bi layer retains high ZT values in relatively broad regions of both temperature and carrier concentration. Our theoretical work emphasizes that the deformation potential constant characterizing the electron-phonon scattering strength is an important paradigm for searching high thermoelectric performance materials.

  2. A Distortion Input Parameter in Image Denoising Algorithms with Wavelets

    Directory of Open Access Journals (Sweden)

    Anisia GOGU

    2009-07-01

    Full Text Available The problem of image denoising based on wavelets is considered. The paper proposes an image denoising method by imposing a distortion input parameter instead of threshold. The method has two algorithms. The first one is running off line and it is applied to the prototype of the image class and it building a specific dependency, linear or nonlinear, between the final desired distortion and the necessary probability of the details coefficients. The next algorithm, is directly applying the denoising with a threshold computed from the previous step. The threshold is estimated by using the probability density function of the details coefficients and by imposing the probability of the coefficients which will be kept. The obtained results are at the same quality level with other well known methods.

  3. Investigating the variability of memory distortion for an analogue trauma.

    Science.gov (United States)

    Strange, Deryn; Takarangi, Melanie K T

    2015-01-01

    In this paper, we examine whether source monitoring (SM) errors might be one mechanism that accounts for traumatic memory distortion. Participants watched a traumatic film with some critical (crux) and non-critical (non-crux) scenes removed. Twenty-four hours later, they completed a memory test. To increase the likelihood participants would notice the film's gaps, we inserted visual static for the length of each missing scene. We then added manipulations designed to affect people's SM behaviour. To encourage systematic SM, before watching the film, we warned half the participants that we had removed some scenes. To encourage heuristic SM some participants also saw labels describing the missing scenes. Adding static highlighting, the missing scenes did not affect false recognition of those missing scenes. However, a warning decreased, while labels increased, participants' false recognition rates. We conclude that manipulations designed to affect SM behaviour also affect the degree of memory distortion in our paradigm.

  4. Sleep Wrinkles: Facial Aging and Facial Distortion During Sleep.

    Science.gov (United States)

    Anson, Goesel; Kane, Michael A C; Lambros, Val

    2016-09-01

    Wrinkles are just one indicator of facial aging, but an indicator that is of prime importance in our world of facial aesthetics. Wrinkles occur where fault lines develop in aging skin. Those fault lines may be due to skin distortion resulting from facial expression or may be due to skin distortion from mechanical compression during sleep. Expression wrinkles and sleep wrinkles differ in etiology, location, and anatomical pattern. Compression, shear, and stress forces act on the face in lateral or prone sleep positions. We review the literature relating to the development of wrinkles and the biomechanical changes that occur in response to intrinsic and extrinsic influences. We explore the possibility that compression during sleep not only results in wrinkles but may also contribute to facial skin expansion.

  5. Mapping flow distortion on oceanographic platforms using computational fluid dynamics

    Directory of Open Access Journals (Sweden)

    N. O'Sullivan

    2013-10-01

    Full Text Available Wind speed measurements over the ocean on ships or buoys are affected by flow distortion from the platform and by the anemometer itself. This can lead to errors in direct measurements and the derived parametrisations. Here we computational fluid dynamics (CFD to simulate the errors in wind speed measurements caused by flow distortion on the RV Celtic Explorer. Numerical measurements were obtained from the finite-volume CFD code OpenFOAM, which was used to simulate the velocity fields. This was done over a range of orientations in the test domain from −60 to +60° in increments of 10°. The simulation was also set up for a range of velocities, ranging from 5 to 25 m s−1 in increments of 0.5 m s−1. The numerical analysis showed close agreement to experimental measurements.

  6. Approximate Characterizations for the Gaussian Source Broadcast Distortion Region

    CERN Document Server

    Tian, Chao; Shamai, Shlomo

    2009-01-01

    We consider the joint source-channel coding problem of sending a Gaussian source over a K-user Gaussian broadcast channel with bandwidth mismatch. A new outer bound to the achievable distortion region is derived using the technique of introducing more than one additional auxiliary random variable, which was previously used to derive sum-rate lower bound for the symmetric Gaussian multiple description problem. By combining this outer bound with the achievability result based on source-channel separation, we provide approximate characterizations of the achievable distortion region within constant multiplicative factors. Furthermore, we show that the results can be extended to general broadcast channels, and the performance of the source-channel separation based approach is also within the same constant multiplicative factors of the optimum.

  7. Morphological Lightcurve Distortions due to Finite Integration Time

    CERN Document Server

    Kipping, David M

    2010-01-01

    We explore how finite integration times or equivalently temporal binning induces morphological distortions to the transit lightcurve. These distortions, if uncorrected for, lead to the retrieval of erroneous system parameters and may even lead to some planetary candidates being rejected as ostensibly unphysical. We provide analytic expressions for estimating the disturbance to the various lightcurve parameters as a function of the integration time. These effects are particularly crucial in light of the long-cadence photometry often used for discovering new exoplanets by for example CoRoT and the Kepler Mission (8.5 and 30 minutes). One of the dominant effects of long integration times is a systematic underestimation of the lightcurve derived stellar density, which has significant ramifications for transit surveys. We present a discussion of numerical integration techniques to compensate for the effects and produce expressions to quickly estimate the errors of such techniques, as a function of integration time...

  8. Bend-Induced Distortion in Large Mode Area Holey Fibre

    Institute of Scientific and Technical Information of China (English)

    TAN Xiao-Ling; GENG You-Fu; ZHANG Tie-Li; WANG Wei-Neng; WANG Peng; YAO Jian-Quan

    2008-01-01

    A simplified scheme of bend-induced mode distortion is introduced into bent holey fibres,the distorted mode distribution and mode effective area reduction are investigated using the finite difference method.Numerical results show that the modes of bent holey fibres with small bend radius shift away from the core and are deformed greatly,and the mode areas drop significantly as the bend radius decreases,which severely affects the fibre laser performance.The propagation characteristics of bent holey fibres at given wavelength are determined by fill factor and normalized bend radius.Finally,the transition normalized bend radius that represents the location of the mode area beginning to fall off is obtained.

  9. Probing correlations of early magnetic fields using mu-distortion

    DEFF Research Database (Denmark)

    Ganc, Jonathan; Sloth, Martin Snoager

    2014-01-01

    \\rangle$ of this distortion with the temperature anisotropy $T$ of the CMB to search for a correlation $\\langle B^2\\zeta\\rangle$ between the magnetic field $B$ and the curvature perturbation $\\zeta$; knowing the $\\langle B^2\\zeta\\rangle$ correlation would help us distinguish between different models of magnetogenesis. Since......_\\mu\\gtrsim 1$ nG, one would have to consider the specifics of the inflationary magnetogenesis model. We also discuss the potential post-magnetogenesis sources of a $\\langle B^2\\zeta\\rangle$ correlation and explain why there will be no contribution from the evolution of the magnetic field in response...... the perturbations which produce the $\\mu$-distortion will be much smaller scale than the relevant density perturbations, the observation of this correlation is sensitive to the squeezed limit of $\\langle B^2\\zeta\\rangle$, which is naturally parameterized by $b_{\\text{NL}}$ (a parameter defined analogously to $f...

  10. Global aspects of elliptical instability in tidally distorted accretion disks

    CERN Document Server

    Ryu, D; Vishniac, E T; Ryu, Dongsu; Goodman, Jeremy; Vishniac, Ethan T

    1995-01-01

    Tidally distorted accretion disks in binary star systems are subject to a local hydrodynamic instability which excites m=1 internal waves. This instability is three dimensional and approximately incompressible. We study the global aspects of this local instability using equations derived under the shearing sheet approximation, where the effects of the azimuthal variation along distorted orbital trajectories are included in source terms which oscillate with local orbital phase. Linear analyses show that the excitation of the instability is essentially local, i.e. insensitive to radial boundary conditions. The region of rapid growth feeds waves into the region of slow or negligible growth, allowing the instability to become global. The global growth rate depends the maximum local growth rate, the size of the rapid growth region, and the local group velocity. We present an empirical expression for the global growth rate. We note that the local nature of the instability allows the excitation of waves with m\

  11. Modelling Thermoelastic Distortion of Optics Using Elastodynamic Reciprocity

    CERN Document Server

    King, Eleanor; Veitch, Peter; Levin, Yuri

    2015-01-01

    Thermoelastic distortion resulting from optical absorption by transmissive and reflective optics can cause unacceptable changes in optical systems that employ high power beams. In advanced-generation laser-interferometric gravitational wave detectors for example, optical absorption is expected to result in wavefront distortions that would compromise the sensitivity of the detector; thus necessitating the use of adaptive thermal compensation. Unfortunately, these systems have long thermal time constants and so predictive feed-forward control systems could be required - but the finite-element analysis is computationally expensive. We describe here the use of the Betti-Maxwell elastodynamic reciprocity theorem to calculate the response of linear elastic bodies (optics) to heating that has arbitrary spatial distribution. We demonstrate using a simple example, that it can yield accurate results in computational times that are significantly less than those required for finite-element analyses.

  12. Atlas-guided correction of brain histology distortion

    Directory of Open Access Journals (Sweden)

    Xi Qiu

    2011-01-01

    Full Text Available Histological tissue preparation stages (e.g., cutting, sectioning, etc. often introduce tissue distortions that prevent a smooth 3D reconstruction from being built. In this paper, we propose a method to correct histology distortions by running a piecewise registration scheme. It takes the information of several consecutive slices in a neighborhood into account. In order to achieve an accurate anatomic presentation, we run the method iteratively with the assistance from a pre-segmented brain atlas. The registration parameters are optimized to accommodate different brain sub-regions, e.g., cerebellum, hippocampus, etc. The results are evaluated by both visual and quantitative approaches. The proposed method has been proved to be robust enough for reconstructing an accurate and smooth mouse brain volume.

  13. Microwave assisted centrifuge and related methods

    Science.gov (United States)

    Meikrantz, David H [Idaho Falls, ID

    2010-08-17

    Centrifuge samples may be exposed to microwave energy to heat the samples during centrifugation and to promote separation of the different components or constituents of the samples using a centrifuge device configured for generating microwave energy and directing the microwave energy at a sample located in the centrifuge.

  14. Microwave heat treating of manufactured components

    Science.gov (United States)

    Ripley, Edward B.

    2007-01-09

    An apparatus for heat treating manufactured components using microwave energy and microwave susceptor material. Heat treating medium such as eutectic salts may be employed. A fluidized bed introduces process gases which may include carburizing or nitriding gases. The process may be operated in a batch mode or continuous process mode. A microwave heating probe may be used to restart a frozen eutectic salt bath.

  15. Microwave Hydrothermal Synthesis PZT of Nanometer Crystal

    Institute of Scientific and Technical Information of China (English)

    Hongxing LIU; Hong DENG; Yan LI; Yanrong LI

    2004-01-01

    It was focused on the applications and developments of microwave hydrothermal synthesis piezoelectric ceramic powder. The microwave hydrothermal vessel was designed and manufactured. The microwave hydrothermal synthesis system was established and the PZT piezoelectric ceramic powder was synthesized. XRD and TEM have been used to characterize the products in detail. The diameter of the PZT powder particle is from 40 to 60 nm.

  16. Fourier-transform microwave spectroscopy of a halogen substituted Criegee intermediate ClCHOO

    Science.gov (United States)

    Cabezas, Carlos; Guillemin, Jean-Claude; Endo, Yasuki

    2016-11-01

    Pure rotational spectra of the chloro-substituted Criegee intermediate (ClCHOO) were observed by Fourier-transform microwave spectroscopy. Two conformers (syn and anti) of the isolated molecule were identified from the rotational spectra of the parent and 37Cl and 13C isotopologues detected in natural abundance. Rotational constants, centrifugal distortion constants, and all components of the nuclear quadrupole coupling tensor were determined for both conformers. Structural features of the molecule have been rationalized with supporting ab initio calculations and the natural bond orbital analysis, which suggest that the conformational preferences are driven by hyperconjugative effects.

  17. Microwave torch. Physics and applications.

    Science.gov (United States)

    Gritsinin, Sergei; Knyazev, Vitalii; Kossyi, Igor

    2004-09-01

    New construction of a coaxial microwave torch (CMT) has been developed, tested and investigated. CMT provides a means for plasma stream production virtually in all gases and gaseous mixture flow at atmospheric pressure. A broad spectrum of diagnostics has been applied including microwave and laser interferometry, optical active and absorptive spectroscopy, laser holographic interferometry, microwave radiation detection, high-speed photography, etc. The time evolution of the torch operating in the pulsed mode is considered. It has been revealed that the evolution is different in noble and molecular gases. The characteristic feature of torches in noble gases is a dense core with plasma density no less than 1016 cm-3. Plasma bunches with density of 1014-1015 cm-3 successively propagate downstream from this core, which are seen as glow bursts. In molecular gases, the core is absent and the torch is formed by propagating plasma bunches. By optical diagnostics application temperature of neutral component of microwave torch has been determined. With high efficiency energy of microwave radiation comes into gas heating. Gas temperature is maximal near the nozzle (4,5 - 5,0 kK) and falls down in axial direction (to 2,5 - 3,0 kK). Torch is thermally-non-equilibrium plasma formation capable of significant change of working and surrounding gaseous state. Peculiarities of discharge development and maintenance are under discussion as well as possibilities to use microwave torch as a spaceborne plasma source, combustion ignitor, mean for nanoparticles production, different plasmachemical applications etc. Contact information: Mailing address: Prof. I.A.Kossyi General Physics Institute, 119991, Vavilov Street 38 Moscow, Russia Tel.: 7(095)135-41-65; Fax: 7(095)135-80-11 E-mail: kossyi@fpl.gpi.ru

  18. Intuitive anatomy: distortions of conceptual knowledge of hand structure

    OpenAIRE

    Longo, Matthew R.

    2015-01-01

    Knowledge of the spatial layout of bodies is mediated by a representation called the body structural description, damage to which results in the condition of autotopagnosia in which patients are impaired in judgments about the location and configuration of body parts. While a large literature has investigated disruption of the body structural description, little research has examined its accuracy in healthy individuals. I show that people have systematically distorted knowledge of the configu...

  19. CMB Spectral Distortions from the Scattering of Temperature Anisotropies

    OpenAIRE

    Stebbins, Albert

    2007-01-01

    Thomson scattering of CMBR temperature anisotropies will cause the spectrum of the CMBR to differ from blackbody even when one resolves all anisotropies. A formalism for computing the anisotropic and inhomogeneous spectral distortions of intensity and polarization is derived in terms of Lorentz invariant central moments of the temperature distribution. The formalism is non-perturbative, requiring neither small anisotropies nor small metric or matter inhomogeneities; but it does assume cold el...

  20. Distortions Imposed By Inflation on Historical-Cost Depreciation

    OpenAIRE

    Boris E Bravo-Ureta

    1983-01-01

    The use of historical-cost depreciation in periods of persistent inflation decreases the present value of depreciation deductions, thus understating the true economic cost of capital and increasing the real after-tax rate of return required by potential investors. Efforts to correct these problems by adopting depreciation methods that allow for artificially short recovery periods or accelerated rates do not provide an adequate solution. Distortions imposed by inflation on historical-cost depr...