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Artykuły w czasopismach na temat „Angular spectrum method”

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Data publikacji: 6 września 2023

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1

Shimobaba, Tomoyoshi, Kyoji Matsushima, Takashi Kakue, Nobuyuki Masuda i Tomoyoshi Ito. "Scaled angular spectrum method". Optics Letters 37, nr 19 (28.09.2012): 4128. http://dx.doi.org/10.1364/ol.37.004128.

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Wu, Sheng Jiang, Dang Juan Li i Jin Jun Lu. "A New Method to Measure the Transmittance of Filter". Advanced Materials Research 383-390 (listopad 2011): 5309–14. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.5309.

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Based on the theory of Fabry-Perot interference, we analyzed the inherent relationship between single-wavelength and the spectrometry, established the mathematical model of transformation from angular spectrum measurement to spectral measurement,realized the data conversion between angular spectrum measurement and spectrum measurement; build the experimental platform and got the laser's transmittance by changing the incidence angle of the laser, and given the comparison experiment by using spectrophotometer, measured the spectral transmittance of filters. Comparison of the two measurement, the results show that:it is a feasible scheme that the angular spectrum measurement replace spectral measurement for filter transmittance .

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3

Schafer, Mark E., i Peter A. Lewin. "Transducer characterization using the angular spectrum method". Journal of the Acoustical Society of America 85, nr 5 (maj 1989): 2202–14. http://dx.doi.org/10.1121/1.397869.

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4

Schafer, M. E., i P. A. Lewin. "Transducer characterization using the angular spectrum method". NDT & E International 25, nr 3 (1992): 152. http://dx.doi.org/10.1016/0963-8695(92)90423-e.

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5

Yan Zhao, Yan Zhao, Liangcai Cao Liangcai Cao, Hao Zhang Hao Zhang, Wei Tan Wei Tan, Shenghan Wu Shenghan Wu, Zheng Wang Zheng Wang, Qiang Yang Qiang Yang i and Guofan Jin and Guofan Jin. "Time-division multiplexing holographic display using angular-spectrum layer-oriented method (Invited Paper)". Chinese Optics Letters 14, nr 1 (2016): 010005–10009. http://dx.doi.org/10.3788/col201614.010005.

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6

Peng, Bofang, Qixin Xu i Wenmei Hou. "A novel overlay metrology method: Simultaneous utilizing spectral and angular spectrum". Optik 169 (wrzesień 2018): 228–35. http://dx.doi.org/10.1016/j.ijleo.2018.05.024.

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7

Arvanitis, Costas D., Calum Crake, Nathan McDannold i Gregory T. Clement. "Passive Acoustic Mapping with the Angular Spectrum Method". IEEE Transactions on Medical Imaging 36, nr 4 (kwiecień 2017): 983–93. http://dx.doi.org/10.1109/tmi.2016.2643565.

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8

Hwang, Chi-Young, Seungtaik Oh, Il-Kwon Jeong i Hwi Kim. "Stepwise angular spectrum method for curved surface diffraction". Optics Express 22, nr 10 (16.05.2014): 12659. http://dx.doi.org/10.1364/oe.22.012659.

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9

Cheng, Qiu-Hu, Shi-Yu Wang, Meng-Yao Wu, Zhen Guo, De-Fang Cai i Bing-Bin Li. "Nonuniform sampled angular spectrum method by using trigonometric interpolation". Chinese Physics B 27, nr 9 (wrzesień 2018): 094203. http://dx.doi.org/10.1088/1674-1056/27/9/094203.

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10

Kim, Yong-Hae, Chun-Won Byun, Himchan Oh, JaeWon Lee, Jae-Eun Pi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu, Hye-Yong Chu i Chi-Sun Hwang. "Non-uniform sampling and wide range angular spectrum method". Journal of Optics 16, nr 12 (27.11.2014): 125710. http://dx.doi.org/10.1088/2040-8978/16/12/125710.

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11

Matsushima, Kyoji. "Shifted angular spectrum method for off-axis numerical propagation". Optics Express 18, nr 17 (13.08.2010): 18453. http://dx.doi.org/10.1364/oe.18.018453.

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12

Kim, Yong-Hae, Chun-Won Byun, Himchan Oh, Jae-Eun Pi, Ji-Hun Choi, Gi Heon Kim, Myung-Lae Lee, Hojun Ryu i Chi-Sun Hwang. "Off-axis angular spectrum method with variable sampling interval". Optics Communications 348 (sierpień 2015): 31–37. http://dx.doi.org/10.1016/j.optcom.2015.03.013.

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13

Grachev, Vladimir, Aleksandr Grischenko, Fedor Bazilevskiy i Maksim Panchenko. "Method for Equalization of Cylinder Powers of Multi-Cylinder Locomotive Diesel". Bulletin of scientific research results 2022, nr 3 (22.09.2022): 103–17. http://dx.doi.org/10.20295/2223-9987-2022-3-103-117.

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Purpose: Labor intensity reduction and equalization accuracy improvement of cylinder powers of a multi-cylinder diesel locomotive on account of application as a diagnostic parameter, characterizing cylinder power unevenness, — the energy of low-frequency band of spectrum for crankshaft instantaneous angular velocity (CIAV) signal. Methods: Methods of mathematical modeling of diesel crankshaft instantaneous angular velocity, mathematical modeling of diesel engine working process, digital signal processing, spectral analysis, differential calculus and multidimensional non-differentiable function optimization are used in the work. Results: Method for equalization of cylinder powers of a multi-cylinder diesel locomotive that’s based on a continuous monitoring of the spectrum of crankshaft instantaneous angular velocity signal is proposed and justified. Energy of low-frequency band of the signal spectrum of CIAV can be used as a diagnostic parameter, characterizing cylinder load unevenness. The parameter value minimization by means of sequential correction of cyclic fuel supply and fuel advance angle ensures the decrease in the pointed unevenness. Practical importance: The proposed method can be used when adjusting fuel equipment after the repair of a diesel engine as with electronic fuel supply control systems as well as with hydromechanical fuel equipment. The use of the given method excludes the necessity of temperature measurement for exhaust gases and flash pressure measurement in cylinders for fuel equipment adjustment that’s especially important for high-speed diesel engines which cylinder heads’ construction doesn’t provide for indicator cocks. In the engines equipped with electronic fuel control systems, the use of IAV signal spectrum low-frequency band energy as a diagnostic parameter makes it possible to automate fully the equalization process for cylinder load. The result of the proposed method application will be the reduction in the duration and labor intensity of diesel locomotives rheostat tests as well as the rise in diesel locomotives reliability and efficiency at the expense of uniform loading of diesel cylinders.

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14

Schoen, Scott, i Costas D. Arvanitis. "Heterogeneous Angular Spectrum Method for Trans-Skull Imaging and Focusing". IEEE Transactions on Medical Imaging 39, nr 5 (maj 2020): 1605–14. http://dx.doi.org/10.1109/tmi.2019.2953872.

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15

Schoen, Scott J., i Costas Arvanitis. "Heterogeneous angular spectrum method for trans-skull imaging and focusing". Journal of the Acoustical Society of America 146, nr 4 (październik 2019): 2813. http://dx.doi.org/10.1121/1.5136742.

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16

Schafer, M. E. "Transducer characterization in inhomogeneous media using the angular spectrum method". NDT & E International 25, nr 3 (1992): 153. http://dx.doi.org/10.1016/0963-8695(92)90434-i.

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17

Lu, Chenxiang, Xiangyang Zeng, Qiang Wang, Lu Wang i Anqi Jin. "Array-Based Underwater Acoustic Target Classification with Spectrum Reconstruction Based on Joint Sparsity and Frequency Shift Invariant Feature". Journal of Marine Science and Engineering 11, nr 6 (23.05.2023): 1101. http://dx.doi.org/10.3390/jmse11061101.

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The target spectrum, which is commonly used in feature extraction for underwater acoustic target classification, can be improperly recovered via conventional beamformer (CBF) owing to its frequency-variant spatial response and lead to degraded classification performance. In this paper, we propose a target spectrum reconstruction method under a sparse Bayesian learning framework with joint sparsity priors that can not only achieve high-resolution target separation in the angular domain but also attain beamwidth constancy over a frequency range at no cost of reducing angular resolution. Experiments on real measured array data show the recovered spectrum via our proposed method can effectively suppress interference and preserve more detailed spectral structures than CBF. This indicates our method is more suitable for target classification because it has the capability of retaining more representative and discriminative characteristics. Moreover, due to target motion and the underwater channel effect, the frequency of prominent spectral line components can be shifted over time, which is harmful to classification performance. To overcome this problem, we proposed a frequency shift-invariant feature extraction method with the help of elaborately designed frequency shift-invariant filter banks. The classification experiments demonstrate that our proposed methods outperform traditional CBF and Mel-frequency features and can help improve underwater recognition performance.

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18

Ali, Rehman, i Jeremy Dahl. "Angular spectrum method for curvilinear arrays: Theory and application to Fourier beamforming". JASA Express Letters 2, nr 5 (maj 2022): 052001. http://dx.doi.org/10.1121/10.0010536.

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Fourier beamforming techniques for medical ultrasound imaging have largely been limited to linear transducer arrays. This work extends the angular spectrum method to curvilinear arrays and demonstrates a migration-based Fourier beamforming technique that has implications for sound speed estimation and distributed aberration correction for abdominal imaging applications. When compared to Field II simulations, the proposed angular spectrum method simulates the pressure field from a focused transmission to within 3.7% normalized root mean square error. The resulting Fourier beamforming technique is then compared to virtual source synthetic aperture using in vivo abdominal imaging examples where resolution and imaging quality improvements are observed.

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19

Sudevan, Vipin, Ujjal Purkayastha i Rajib Saha. "A Partial-sky Gibbs ILC Approach for the Estimation of CMB Posterior over Large Angular Scales of the Sky". Astrophysical Journal 936, nr 2 (1.09.2022): 106. http://dx.doi.org/10.3847/1538-4357/ac8105.

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Abstract In this article we present a formalism for incorporating the partial-sky maps into the Gibbs ILC algorithm to estimate the joint posterior density of the cosmic microwave background (CMB) signal and the theoretical CMB angular power spectrum given the observed CMB maps. In order to generate the partial-sky maps, we mask all the observed CMB maps provided by the WMAP and Planck satellite full-sky mission using a mask that removes 22% of the entire sky. The mask we use is based on the strength of the thermal dust emissions in the Planck 353 GHz map. While implementing the Gibbs ILC method on the partial-sky maps, we convert the partial-sky-cleaned angular power spectrum into the full-sky angular power spectrum using the mode-mode coupling matrix estimated from the smoothed mask. The main products of our analysis are a partial-sky cleaned best-fit CMB map and an estimate of the underlying full-sky theoretical CMB angular power spectrum in the multipole range 2 ≤ ℓ ≤ 32 along with their error estimates. We validate the method by performing detailed Monte Carlo simulations after using realistic models of foregrounds and detector noise consistent with the WMAP and Planck frequency channels used in our analysis. We can estimate the posterior density and full-sky theoretical CMB angular power spectrum without any need to explicitly model the foreground components from partial-sky maps using our method. Another important feature of this method is that the power spectrum results along with the error estimates can be directly used for cosmological parameter estimations.

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20

Makarov, Denis V., i Leonid E. Kon’kov. "Angular Spectrum of Acoustic Pulses at Long Ranges". Journal of Marine Science and Engineering 11, nr 1 (27.12.2022): 29. http://dx.doi.org/10.3390/jmse11010029.

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Long-range propagation of sound pulses in the deep ocean is considered. A new method for the estimation of the pulse angular spectrum is presented. The method is based on the Husimi transform of a wave field and can be realized with a short vertical array of nondirectional hydrophones. As a result, one obtains a diagram of the arrival pattern in the time–angle plane. The method is applied to a model of the underwater sound channel in the Sea of Japan. Special attention is paid to sound scattering on a cold synoptic eddy along the waveguide. It is shown that the synoptic eddy leads to a splitting of the individual ray’s arrivals into clusters with close angles and times. The random sound-speed perturbation induced by internal waves blurs these clusters into a fuzzy background and simultaneously broaden the angular spectrum of pulses. Nevertheless, it is found that the latter effect is relatively weak for short vertical arrays. In particular, it is shown that increasing the array length from 10 to 30 m results in the separation of the arrivals with opposite angles.

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21

Yatsishen, Valeriy V. "Nanoplasmonic methods in angular spectroscopy of nanoscale biological objects". Physics of Wave Processes and Radio Systems 23, nr 4 (11.02.2021): 111–15. http://dx.doi.org/10.18469/1810-3189.2020.23.4.111-115.

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The paper presents the results of calculating the angular spectra of light reflection under the condition of excitation of surface plasmons in the Kretschman scheme. The silver layer in this scheme plays the role of a reference material, the minimum in the angular spectrum of which serves as a reference point for the shift of the minimum of the angular spectrum when a layer of the studied biological material is added to the considered layered system, which were melanin and biological tissue. As a result of the work, specific pronounced minima in the angular spectra were obtained, which make it possible to identify these materials with a high degree of accuracy due to the narrow resonance peaks in the angular reflection spectra, which are spaced from the peak in the reflection from the silver film by certain angles. The method contains all the characteristic features of the resonance spectroscopy method; the conditions for the excitation of a surface plasmon at the metal boundary act as resonance conditions.

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22

Leung, J. S. Y., J. Hartley, J. M. Nagy, C. B. Netterfield, J. A. Shariff, P. A. R. Ade, M. Amiri i in. "A Simulation-based Method for Correcting Mode Coupling in CMB Angular Power Spectra". Astrophysical Journal 928, nr 2 (30.03.2022): 109. http://dx.doi.org/10.3847/1538-4357/ac562f.

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Abstract Modern cosmic microwave background (CMB) analysis pipelines regularly employ complex time-domain filters, beam models, masking, and other techniques during the production of sky maps and their corresponding angular power spectra. However, these processes can generate couplings between multipoles from the same spectrum and from different spectra, in addition to the typical power attenuation. Within the context of pseudo-C ℓ based, MASTER-style analyses, the net effect of the time-domain filtering is commonly approximated by a multiplicative transfer function, F ℓ , that can fail to capture mode mixing and is dependent on the spectrum of the signal. To address these shortcomings, we have developed a simulation-based spectral correction approach that constructs a two-dimensional transfer matrix, J ℓ ℓ ′ , which contains information about mode mixing in addition to mode attenuation. We demonstrate the application of this approach on data from the first flight of the Spider balloon-borne CMB experiment.

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23

Wang, Wantian, Jiahao Zhang, Hao Wu i Jin Meng. "An Adaptive and Accurate Method for Rotational Angular Velocity Estimation of Rotor Targets via Fourier Coefficient Interpolation". Remote Sensing 14, nr 17 (1.09.2022): 4342. http://dx.doi.org/10.3390/rs14174342.

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As a special micro-motion feature of rotor targets, rotational angular velocity can provide a discriminant basis for target classification and recognition. In this paper, an adaptive and accurate method is proposed for estimating the rotational angular velocity of rotor targets via a Fourier coefficient interpolation algorithm that is based on modified frequency index residue initialization. The negative frequency complex exponential signal component is removed at each iteration to eliminate the estimation bias caused by spectrum superposition and improve the estimation accuracy. The frequency index residue initialization is modified, based on a normalized Fourier spectrum, to improve the estimable range of the rotational angular velocity and reduce the computational complexity of the algorithm. The simulation results show that the estimation performance of the proposed method achieves the Cramér–Rao lower bound and outperforms state-of-the-art methods in terms of the estimable range and estimation accuracy of the rotational angular velocity.

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24

Fang, Yuzhuo, i Zhiyong Xu. "Multiple Sound Source Localization and Counting Using One Pair of Microphones in Noisy and Reverberant Environments". Mathematical Problems in Engineering 2020 (7.09.2020): 1–12. http://dx.doi.org/10.1155/2020/8937829.

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A multiple sound source localization and counting method based on an angular spectrum is proposed in this paper. Local signal-to-noise ratio tracking, onset detection, and a coherence test are introduced to filter the generalized cross-correlation angular spectrum in the time-frequency domain for multiple sound source localization and counting in noisy and reverberant environments. Then, dual-width matching pursuit is introduced to replace peak search as the method of localization and counting. A comprehensive comparison of two statistical indicators, mean precision and mean absolute estimated error, indicates that the proposed localization and counting algorithm using both the filtered angular spectrum and dual-width matching pursuit method is more robust and accurate than the classic counterpart, especially in environments with low signal-to-noise ratio, strong reverberation, and abundant sound sources.

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25

Zhang Xusheng, 张旭升, 何川 He Chuan i 撖芃芃 Han Pengpeng. "Intensity Distribution Analysis of Axicon Lens by Numerical Angular Spectrum Method". Acta Optica Sinica 32, nr 12 (2012): 1207001. http://dx.doi.org/10.3788/aos201232.1207001.

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Zhang, Wenhui, Hao Zhang, Kyoji Matsushima i Guofan Jin. "Shifted band-extended angular spectrum method for off-axis diffraction calculation". Optics Express 29, nr 7 (16.03.2021): 10089. http://dx.doi.org/10.1364/oe.419096.

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27

He, Zehao, Xiaomeng Sui, Guofan Jin i Liangcai Cao. "Distortion-Correction Method Based on Angular Spectrum Algorithm for Holographic Display". IEEE Transactions on Industrial Informatics 15, nr 11 (listopad 2019): 6162–69. http://dx.doi.org/10.1109/tii.2019.2906642.

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28

Lewin, Peter A., i Mark E. Schafer. "Characterization of the surface velocity distribution using the angular spectrum method". Journal of the Acoustical Society of America 88, S1 (listopad 1990): S172. http://dx.doi.org/10.1121/1.2028763.

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29

Vecchio, Christopher J., i Peter A. Lewin. "Finite amplitude acoustic propagation modeling using the extended angular spectrum method". Journal of the Acoustical Society of America 95, nr 5 (maj 1994): 2399–408. http://dx.doi.org/10.1121/1.409849.

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30

Xu, Rui, Ming Feng, Ziyu Chen, Jiaxin Yang, Dongdong Han, Jinyue Xie i Feng Song. "Non-uniform angular spectrum method in a complex medium based on iteration". Optics Letters 47, nr 8 (7.04.2022): 1972. http://dx.doi.org/10.1364/ol.454171.

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31

Fung, Clement C. W., Richard S. C. Cobbold i Peter A. J. Bascom. "Radiation coupling of a transducer–target system using the angular spectrum method". Journal of the Acoustical Society of America 92, nr 4 (październik 1992): 2239–47. http://dx.doi.org/10.1121/1.405218.

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32

Zhao, Wanli, Chenlu Wei, Caojin Yuan, Chenliang Chang, Jun Ma i Rihong Zhu. "A flexible numerical calculation method of angular spectrum based on matrix product". Optics Letters 45, nr 21 (23.10.2020): 5937. http://dx.doi.org/10.1364/ol.405257.

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Zhao, Yan, Liangcai Cao, Hao Zhang, Dezhao Kong i Guofan Jin. "Accurate calculation of computer-generated holograms using angular-spectrum layer-oriented method". Optics Express 23, nr 20 (21.09.2015): 25440. http://dx.doi.org/10.1364/oe.23.025440.

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Li, Yuanyang, Jin Guo, Lisheng Liu, Tingfeng Wang i Junfeng Shao. "Wide-window angular spectrum method for optical field propagation through ABCD systems". Journal of Modern Optics 61, nr 18 (30.07.2014): 1519–28. http://dx.doi.org/10.1080/09500340.2014.944232.

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Kozacki, Tomasz, i Konstantinos Falaggis. "Angular spectrum method with compact space–bandwidth: generalization and full-field accuracy". Applied Optics 55, nr 19 (22.06.2016): 5014. http://dx.doi.org/10.1364/ao.55.005014.

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Belgroune, D., J. F. de Belleval i H. Djelouah. "Angular Spectrum Method for the Focused Acoustic Field of a Linear Transducer". Physics Procedia 70 (2015): 231–35. http://dx.doi.org/10.1016/j.phpro.2015.08.143.

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Secada, José D. "Transient radiation field of annular-sectorial planar pistons: The Angular Spectrum method". Wave Motion 44, nr 1 (listopad 2006): 1–20. http://dx.doi.org/10.1016/j.wavemoti.2006.06.004.

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Zhang, Wenhui, Hao Zhang i Guofan Jin. "Adaptive-sampling angular spectrum method with full utilization of space-bandwidth product". Optics Letters 45, nr 16 (4.08.2020): 4416. http://dx.doi.org/10.1364/ol.393111.

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Umiltà, C., J. F. Cardoso, K. Benabed i M. Le Jeune. "The CMB angular power spectrum via component separation: a study on Planck data". Astronomy & Astrophysics 624 (kwiecień 2019): A67. http://dx.doi.org/10.1051/0004-6361/201833758.

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Aims. We investigate the extent to which foreground-cleaned cosmic microwave background (CMB) maps can be used to estimate cosmological parameters at small scales. Methods. We use the SMICA method, a blind separation technique that works directly at the spectral level. In this work we focus on the small scales of the CMB angular power spectrum, which are chiefly affected by noise and extragalactic foregrounds, such as point sources. We adapt SMICA to use only cross-spectra between data maps, thus avoiding the noise bias. In this study, performed using both simulations and Planck 2015 data, we fit for extragalactic point sources by modelling them as shot noise of two independent populations. Results. In simulations, we correctly recover the point-source emission law, and obtain a CMB angular power spectrum that has an average foreground residual of one fifth of the CMB power at ℓ ≥ 2200. With Planck data, the recovered point-source emission law corresponds to external estimates, with some offsets at the highest and lowest frequencies, possibly due to frequency decoherence of point sources. The CMB angular power spectrum residuals are consistent with what we find in simulations. The cosmological parameters obtained from the simulations and the data show offsets up to 1σ on average from their expected values. Biases on cosmological parameters in simulations represent the expected level of bias in Planck data. Conclusions. The results on cosmological parameters depend on the detail of the foreground residual contamination in the spectrum, and therefore a tailored modelling of the likelihood foreground model is required.

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Grachev, Vladimir, Aleksandr Grischenko, Fedor Bazilevskiy i Maksim Panchenko. "Experimental Verification of Equalization Method for the Outputs of Multi-Cylinder Diesel Engine Cylinders". Bulletin of scientific research results 2022, nr 4 (24.12.2022): 24–36. http://dx.doi.org/10.20295/2223-9987-2022-4-24-36.

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Purpose: The purpose of the present work is to test experimentally equalization method for the outputs of multi-cylinder diesel engine cylinders basing on energy minimization of amplitude spectrum low-frequency band for diesel crankshaft instantaneous angular speed signal. Methods: The work uses the methods of digital signal processing, spectral analysis, differential calculus, multidimensional undifferentiated function optimization, experimental results processing. Results: The fulfilled experimental studies at bench diesel generator device as a part of locomotive diesel D50 (6CHN31.8/33) and traction generator MPT 84/39 ensure the possibility to use proposed earlier method for power equalization for the cylinders of multi-cylinder diesel engine basing on energy control of amplitude spectrum low-frequency band of crankshaft instantaneous angular speed signal. Unrvenness index for cylinder power is proposed, its sensitivity to cyclic supply change and the advance angle of fuel supply to diesel engine individual cylinders is estimated. Practical significance: The possibility to apply being proposed equalization method for the powers of multi-cylinder diesel engine cylinders for to adjust fuel equipment after diesel engine repair as with the systems of electronic fuel supply control as well as with hydromechanical fuel equipment has been confirmed experimentally. The use of given method eliminates the need to measure the temperature of exhaust gases and flash pressure in cylinders for fuel equipment adjustment that’s especially important for high-speed diesel engines which cylinder cover construction doesn’t imply indicated valves.

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41

Konstantinovich, I. A., i A. V. Konstantinovich. "Radiation Spectrum of Sequence of Electrons Moving in Spiral in Medium". Фізика і хімія твердого тіла 20, nr 1 (11.04.2019): 5–12. http://dx.doi.org/10.15330/pcss.20.1.12.

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Integral expressions for spectral-angular and spectral distributions of the radiation power for the sequence of electrons moving in magnetic fields in isotropic transparent medium are investigated using the improved Lorentz`s self-interaction method. Special attention is given to the research of the fine structurre of the spectral distribution of the synchrotron-Cherenkov radiation of one, two, three and four point electrons moving along the spiral in medium. The effects of coherent radiation of harmonics and oscillations in spectrum of the synchrotron-Cherenkov radiation of two, three and four point electrons are established and investigated using the direct numerical method for calculation the function of spectral distributions of the radiation power.

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42

Vyas, Urvi, i Douglas Christensen. "Ultrasound beam simulations in inhomogeneous tissue geometries using the hybrid angular spectrum method". IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 59, nr 6 (czerwiec 2012): 1093–100. http://dx.doi.org/10.1109/tuffc.2012.2300.

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Zhang, Xiao-Zheng, Chuan-Xing Bi, Yong-Bin Zhang i Liang Xu. "Reconstruction of nonstationary sound fields based on a time domain angular spectrum method". Journal of the Acoustical Society of America 148, nr 4 (październik 2020): 2123–36. http://dx.doi.org/10.1121/10.0002263.

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Ritter, André. "Modified shifted angular spectrum method for numerical propagation at reduced spatial sampling rates". Optics Express 22, nr 21 (17.10.2014): 26265. http://dx.doi.org/10.1364/oe.22.026265.

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Ebers, Lena, Manfred Hammer i Jens Förstner. "Light diffraction in slab waveguide lenses simulated with the stepwise angular spectrum method". Optics Express 28, nr 24 (16.11.2020): 36361. http://dx.doi.org/10.1364/oe.409612.

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Pees, Edward H. "A radial propagator for computing axisymmetric pressure fields using the angular spectrum method." Journal of the Acoustical Society of America 126, nr 4 (2009): 2197. http://dx.doi.org/10.1121/1.3248593.

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Yu, Xiao, Tang Xiahui, Qin Ying xiong, Peng Hao i Wang Wei. "Wide-window angular spectrum method for diffraction propagation in far and near field". Optics Letters 37, nr 23 (28.11.2012): 4943. http://dx.doi.org/10.1364/ol.37.004943.

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Suh, Kyung Duck, Robert A. Dalrymple i James T. Kirby. "An angular spectrum model for propagation of Stokes waves". Journal of Fluid Mechanics 221 (grudzień 1990): 205–32. http://dx.doi.org/10.1017/s0022112090003548.

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An angular spectrum model for predicting the transformation of Stokes waves on a mildly varying topography is developed, including refraction, diffraction, shoaling and nonlinear wave interactions. The equations governing the water-wave motion are perturbed using the method of multiple scales and Stokes expansions for the velocity potential and free-surface displacement. The first-order solution is expressed as an angular spectrum, or directional modes, of the wave field propagating on a beach with straight iso-baths whose depth is given by laterally averaged depths. The equations for the evolution of the angular spectrum due to the effects of bottom variation and cubic resonant interaction are obtained from the higher-order problems. Comparison of the present model with existing models is made for some simple cases. Numerical examples of the time-independent version of the model are presented for laboratory experiments for wave diffraction behind a breakwater gap and wave focusing over submerged shoals: an elliptic shoal on a sloping beach and a circular shoal on a flat bottom.

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Carrion, Philip M., Selma dos S. Sacramento i Reynam da C. Pestana. "Source wavelet and its angular spectrum from plan‐wave seismograms". GEOPHYSICS 55, nr 8 (sierpień 1990): 1026–35. http://dx.doi.org/10.1190/1.1442915.

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In a typical seismic experiment (land or marine), the generated source wavelet is either unknown, or known only approximately. In order to solve many geophysical problems, an accurate wavelet estimation is crucial. This paper demonstrates a fast numerical algorithm which allows not only estimating the source wavelet but also its angular spectrum (radiation pattern) from plane‐wave decomposed seismograms. Surprisingly, literature on this subject is virtually missing, although a nonuniform angular spectrum of the generated wavelet can substantially affect the recorded data. The technique presented here is based on the downward continuation (DC) and reverse‐time extrapolation (RTE) of the recorded data (both pressure and its vertical derivative). The proposed method is iterative: The rate of convergence does not depend on phase characteristics of the generated wavelet. We demonstrate that both the wavelet signature and its angular spectrum can be estimated accurately from plane‐wave seismograms. We also illustrate the technique on a variety of wavelets with different amplitude/phase characteristics.

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VALENCIA, ALEJANDRA, MARTIN HENDRYCH, XIAOJUAN SHI i JUAN P. TORRES. "ANGULAR DISPERSION IN SPONTANEOUS PARAMETRIC DOWN CONVERSION: A TOOL TO GENERATE NARROW TEMPORAL BIPHOTONS AND PURE HERALDED SINGLE PHOTONS". International Journal of Quantum Information 07, supp01 (styczeń 2009): 9–15. http://dx.doi.org/10.1142/s0219749909004906.

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In this paper, we describe how introducing angular dispersion into the pump beam and the downconverted photons in spontaneous parametric downconversion allows us to manipulate the joint spectrum of the paired photons. In particular, when collinear geometries are used, we demonstrate an increase of the photons' bandwidth and discuss the implications of this method for the generation of narrow temporal Fourier transform limited biphotons. Additionally, we describe the situation in which angular dispersion is combined with noncollinear geometries. In this case, a full control of the joint spectrum is achieved and heralded pure single photons with controllable bandwidth can be obtained.

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