Journal articles: 'ANGULAR FILTERING IN TRANSMISSION SPECTRUM'

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Shevchenko, M. E., A. V. Gorovoy, and S. N. Solovyov. "Spatial filtering of signals with spectrum overlapping." Issues of radio electronics, no. 12 (December 28, 2019): 27–33. http://dx.doi.org/10.21778/2218-5453-2019-12-27-33.

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The paper considers the spatial filtering methods of signals with spectrum overlapping under conditions of a priori uncertainty of the directions of arrival from radio sources. The estimates of the directions of signals arrival obtained by ESPRIT or MUSIC are used in order to build a spatial filter. It is shown that when using ESPRIT, unlike MUSIC, an additional calculations of filter coefficients based on estimates of the directions of signals arrival are not required, and the quadrature components of the signals are formed simultaneously with estimates of the direction of their arrival. The probability of error performances of minimum shift keying signals which were divided by spatial filtering on the basis of ESPRIT and MUSIC using seven-element circular and angular antenna arrays are given.

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Zakirullin, R., and I. Odenbakh. "Smart window for angular selective filtering of solar radiation." E3S Web of Conferences 124 (2019): 01002. http://dx.doi.org/10.1051/e3sconf/201912401002.

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A new approach to angular selective filtering of the solar radiation without using the sunlight redistribution devices is proposed. Parallel strips of chromogenic materials on two surfaces of the pane(s) form an optical filter having angular selective light transmission. Clarified methods to calculate the optimum slope angle of the strips on the pane(s), their widths and relative position on two surfaces considering the seasonal and daily change in the solar radiation, the location of the building and the window’s azimuth are presented. Such a smart window blocks the direct radiation in a preset angular range and transmits the scattered and reflected radiation that is provides comfortable daylighting indoors.

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Liu, Wei-Nan, Rui Chen, Wei-Yi Shi, Ke-Bo Zeng, Fu-Li Zhao, and Jian-Wen Dong. "Narrow-frequency sharp-angular filters using all-dielectric cascaded meta-gratings." Nanophotonics 9, no. 10 (June 17, 2020): 3443–50. http://dx.doi.org/10.1515/nanoph-2020-0141.

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AbstractSelective transmission or filtering always responds to either frequency or incident angle, so as hardly to maximize signal-to-noise ratio in communication, detection and sensing. Here, we propose compact meta-filters of narrow-frequency sharp-angular transmission peak along with broad omnidirectional reflection sidebands, in all-dielectric cascaded subwavelength meta-gratings. The inherent collective resonance of waveguide-array modes and thin film approximation of meta-grating are employed as the design strategy. A unity transmission peak, locating at the incident angle of 44.4° and the center wavelength of 1550 nm, is demonstrated in a silicon meta-filter consisting of two-layer silicon rectangular meta-grating. These findings provide possibilities in cascaded meta-gratings spectroscopic design and alternative utilities for high signal-to-noise ratio applications in focus-free spatial filtering and anti-noise systems in telecommunications.

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Kobayashi, Ricardo Tadashi, Aislan Gabriel Hernandes, Mario Lemes Proença, and Taufik Abrao. "Improved MB Cognitive Radio Spectrum Sensing Using Wavelet Spectrum Filtering." Journal of Circuits, Systems and Computers 28, no. 08 (July 2019): 1950136. http://dx.doi.org/10.1142/s0218126619501366.

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In cognitive radio (CR), the sensed aggregate bandwidth could be as large as several GHz. This is especially challenging if the bandwidths and central frequencies of the sensed signals are unknown and need to be estimated. This work discusses a new improved method for MB spectrum sensing (iMB-SS) based on edge detection and using Wavelet Spectrum Filtering. The proposed iMB-SS method uses a Welch power spectrum density (PSD) estimate and a multi-scale Wavelet approach to reveal the spectrum transition (edges), which is deployed to characterize the spectrum occupancy in CR scenarios where the operation frequencies of the primary users (PUs) are unknown. The focus of this work lies in improving the performance of the MB spectrum sensor, particularly by refining the spectral edge location and reducing misleading detection. A comprehensive analytical description and numerical analysis have been carried out by focusing on orthogonal-frequency-division-multiplexing (OFDM) signal applications in CR networks. Numerical results corroborate the effectiveness of the proposed iMB-SS approach. The simulated results for the multiple-PU’s OFDM-based transmission CR system demonstrate that the proposed iMB-SS method can achieve high performance even under low signal-to-noise ratio (SNR) regime, turning it out as an attractive choice for SS in the MB CR systems.

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Zhang, Chao, and Xuefeng Jiang. "Secure high-speed spread spectrum transmission system with orbital angular momentum." IET Communications 14, no. 11 (July 14, 2020): 1709–17. http://dx.doi.org/10.1049/iet-com.2019.0976.

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Iizuka, Hideo, Nader Engheta, and Shinya Sugiura. "Extremely small wavevector regime in a one-dimensional photonic crystal heterostructure for angular transmission filtering." Optics Letters 41, no. 16 (August 9, 2016): 3829. http://dx.doi.org/10.1364/ol.41.003829.

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Nesterenko, D. V., A. A. Morozov, and L. L. Doskolovich. "Optical image edge detection by transmissive metal-dielectric-metal structures." Computer Optics 5, no. 45 (September 2021): 678–84. http://dx.doi.org/10.18287/2412-6179-co-853.

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The feasibility of an optical image edge detection based on metal-insulator-metal (MIM) resonance transmission structures is experimentally investigated. The structures are fabricated on a glass substrate and consist of thin aluminum layers separated by a quartz layer. The excitation of Fabry-Perot modes by an incident wave produces resonance line shapes in angular and wavelength transmission spectra. Resonance enhancement and suppression of beams using the MIM structures can be implemented for suppressing the illuminating beam and amplifying the field scattered by an object. By using the MIM structure under oblique incidence, we experimentally observe the efficient image edge detection for phase optical elements at a set of wavelengths. The obtained images of edges of the elements exhibit a directionality of image edge detection that depends on the direction of inhomogeneity gradient in the object plane, as suggested by the angular transmission spectra of the MIM structures. The results of the present work can find applications in optical information processing and optical filtering systems.

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Nesterenko, D. V., A. A. Morozov, and L. L. Doskolovich. "Optical image edge detection by transmissive metal-dielectric-metal structures." Computer Optics 5, no. 45 (September 2021): 678–84. http://dx.doi.org/10.18287/2412-6179-co-853.

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The feasibility of an optical image edge detection based on metal-insulator-metal (MIM) resonance transmission structures is experimentally investigated. The structures are fabricated on a glass substrate and consist of thin aluminum layers separated by a quartz layer. The excitation of Fabry-Perot modes by an incident wave produces resonance line shapes in angular and wavelength transmission spectra. Resonance enhancement and suppression of beams using the MIM structures can be implemented for suppressing the illuminating beam and amplifying the field scattered by an object. By using the MIM structure under oblique incidence, we experimentally observe the efficient image edge detection for phase optical elements at a set of wavelengths. The obtained images of edges of the elements exhibit a directionality of image edge detection that depends on the direction of inhomogeneity gradient in the object plane, as suggested by the angular transmission spectra of the MIM structures. The results of the present work can find applications in optical information processing and optical filtering systems.

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Qin, Li, and Wen Jing Ding. "Rain-Wind-Induced Analysis of Transmission Steel Tower." Advanced Materials Research 450-451 (January 2012): 64–67. http://dx.doi.org/10.4028/www.scientific.net/amr.450-451.64.

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The paper established a finite element model of DZV674 linear tower (500 kV Shiyang - Wuyi transmission project) by ANSYS and studies its dynamic properties. Its first 10 order modes and natural vibration period are obtained. Based on the principle of Kaimal power spectrum and linear filtering method (AR) for simulation time-history of fluctuating wind speed, power spectrum simulation program of wind-speed is got by using Matlab. The rain load simulation is finished on the former simulation.The dynamic analysis of the transmission tower is calculated subject to wind load and rain-wind load.The results demonstrate that wind is the main design load in rain-wind-induced, but the effect of rain shouldn’t be neglected.

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Tur’yanskii, A. G., S. S. Gizha, and V. M. Senkov. "Broadband Filtering of an X-Ray Spectrum by Transmission through a Polycapillary Structure." Technical Physics Letters 44, no. 12 (December 2018): 1208–10. http://dx.doi.org/10.1134/s1063785019010176.

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Spratt, Kyle S., Benjamin C. Treweek, Kevin M. Lee, Michael R. Haberman, and Mark F. Hamilton. "Measuring the transmission coefficient of a steel plate using an angular spectrum approach." Journal of the Acoustical Society of America 145, no. 3 (March 2019): 1924. http://dx.doi.org/10.1121/1.5101990.

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Ali, Rehman, and Jeremy Dahl. "Angular spectrum method for curvilinear arrays: Theory and application to Fourier beamforming." JASA Express Letters 2, no. 5 (May 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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Hunt, J. A., G. Kothleitner, and R. Harmon. "Comparison of STEM EELS Spectrum Imaging vs EFTEM Spectrum Imaging." Microscopy and Microanalysis 5, S2 (August 1999): 616–17. http://dx.doi.org/10.1017/s1431927600016408.

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Electron energy-loss spectroscopy (EELS) in the transmission electron microscope (TEM) analyzes the energy distribution of the probe electrons after they have lost energy within the sample. The resultant energy-losses are characteristic of elemental, chemical, and dielectric properties and are typically measured in one of two ways. Parallel-detection EELS spectrometers (PEELS) acquire large energy ranges of the energy-loss spectrum simultaneously for rapid acquisition of spectral data at a single area. In contrast, the energy filtering TEM (EFTEM) acquires only a single energy band at once, but does so for thousands or even millions of image pixels simultaneously.Spectrum imaging (SI) involves acquisition of detailed spectroscopic data sufficient for rigorous analysis at each pixel in a digital image. (Fig. la) A STEM EELS spectrum image “data cube” can be acquired by stepping a focused electron probe to each pixel and filling the spectrum image one spectrum at a time.

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Leapman, R. D., C. M. Brooks, N. W. Rizzo, and T. L. Talbot. "Quantitative Analysis Of Bological Specimens by Spectrum-Imaging in the Energy Filtering Transmission Electron Microscope." Microscopy and Microanalysis 6, S2 (August 2000): 160–61. http://dx.doi.org/10.1017/s1431927600033298.

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Electron energy loss spectrum-imaging (EELSI) in the energy filtering transmission electron microscope (EFTEM) can provide more accurate analysis of elemental distributions than that obtainable by the standard two-window or three-window background subtraction techniques. Spectra containing many channels can be extracted from regions of interest and analyzed using established methods for quantitation. For example, the pre-edge background can be fitted by an inverse power law and subtracted from the post-edge spectrum. EELSI in the EFTEM is often superior to spectrum-imaging in the scanning transmission electron microscope for mapping specimen regions of size greater than 1 μm. This is due the much larger total beam current that is available at the specimen in a fixed-beam microscope relative to a scanned-beam microscope. Our aim here is demonstrate the advantages of such EELSI measurements for analysis of biological specimens. However, we also indicate some potential pitfalls in acquiring elemental maps in the EFTEM, which can be attributed to specimen instabilities during the acquisition.

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Wang, Ji Xin, Nai Xiang Wang, Xiang Jun Yu, Yong Hai Yang, and Ming Yao Yao. "A Method for Compiling Load Spectrum of Transmission System of Wheel Loader." Advanced Materials Research 108-111 (May 2010): 1314–19. http://dx.doi.org/10.4028/www.scientific.net/amr.108-111.1314.

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The structural durability of wheel loader are required to estimate on the basis of design loading spectrum, which is a spectrum combination of various operating and loading conditions. To generate the load spectrum of transmission system, an actual operational loads of wheel loader under the driving cycle was investigated. A signal collection system was applied to get time-history voltage signals and then torque loads were obtained according to the conversion coefficient between voltage and torque. After zeroing and filtering, the mean, the amplitude and number of load cycles were gained with the rain-flow counting method. The mean and amplitude were tested by Nominal distribution and Weibull distribution respectively. Test results show that they are independent. The two-dimensional joint probability density function of amplitude and mean was gained. After extrapolation, the load spectrum of the spacerflange under whole-life cycle is gained and the process of compiling load spectrum is also provided.

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Leung, J. S. Y., J. Hartley, J. M. Nagy, C. B. Netterfield, J. A. Shariff, P. A. R. Ade, M. Amiri, et al. "A Simulation-based Method for Correcting Mode Coupling in CMB Angular Power Spectra." Astrophysical Journal 928, no. 2 (March 30, 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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Zhai, Xiang, Shuangchun Wen, Dong Xiang, Ling-Ling Wang, Wujiaihemaiti Rexidaiguli, Liu Wang, and Dianyun Fan. "A Subwavelength Plasmonic Waveguide Filter with a Ring Resonator." Journal of Nanomaterials 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/484207.

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The transmission characteristics of the electromagnetic wave are numerically investigated in two-dimensional compound plasmonic structures composed of two straight subwavelength metal-insulator-metal (MIM) waveguides and a ring resonator. The two straight MIM waveguides situate on both sides of the ring resonator, and the MIM waveguide of the outgoing side has a positional angular deviationθrelative to the MIM waveguide of the incoming side. The results show that the filtering performances of the asymmetric structures(θ≠0∘)are greatly improved in comparison with the symmetric structure(θ=0∘). For most of the asymmetric structures, there is a transmission minimum at the slightly bigger wavelength than one at which the transmission peak appears for the symmetric structures, and there is still a transmission peak at the wavelength of the transmission peak of the symmetric structures. Moreover, the difference between the transmission peak and valley is increased, and the breadth of the transmission peak becomes narrow.

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Mayer, J., M. Pidun, P. Karduck, A. Zern, and K. Hahn. "Prospects and Limitations of Energy Filtering TEM in Spectrum Imaging Analysis." Microscopy and Microanalysis 6, S2 (August 2000): 1054–55. http://dx.doi.org/10.1017/s1431927600037764.

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The increasing number of energy filtering transmission electron microscopes (EFTEMs) has given many microscopists the ability to apply the fast and very efficient tool of electron spectroscopic imaging (ESI) for analytical characterisation, rather than to record EELS spectra. In a more general framework, the new ESI methods and the standard PEELS technique both aim at exploring the same three-dimensional data space. This data space is represented by the spatial co-ordinates x, y and the energy loss ΔE. The resulting intensity distribution I(x,y, ΔE) is frequently referred to as a spectrum image and the experimental techniques to acquire the corresponding data are referred to as spectrum imaging. The actual analysis can either be based on recording PEELS spectra for a twodimensional array of probe positions, or on recording series of energy filtered images across inner shell loss edges or in the low loss region.

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Hiismäki, P. "Background-filtered transmission diffraction with internal intensity calibration." Journal of Applied Crystallography 22, no. 2 (April 1, 1989): 79–83. http://dx.doi.org/10.1107/s0021889888010015.

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It is inferred that by frequency filtering the logarithm of the time-of-flight spectrum of neutrons that have passed through a powdered isotropic crystalline sample a diffractogram may be obtained with many desirable properties for achieving high-quality refinement of structural parameters. Apart from multiple scattering no wavelength-dependent effects or corrections need to be introduced, which implies automatic internal calibration of the Bragg intensities. For utilization of the inherent high resolution of the transmission geometry, a Fourier chopper in the pulsed beam from an intensity-optimized quasi-steady-state moderator is suggested. Results of model calculations are presented.

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Reimer, L. "Energy-filtering Transmission Electron Microscopy in materials and life science." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 936–37. http://dx.doi.org/10.1017/s0424820100172413.

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Energy-filtering transmission electron microscopy can be realized by an imaging filter lens in thecolumn of a TEM, a post-column electron energy-loss spectrometer or a dedicated STEM. This offers new possibilities in analytical electron microscopy by combining the operation modes of electron-spectroscopic imaging (ESI), electron-spectroscopic diffraction (ESD) and the record of an electron energy-loss spectrum (EELS).ESI can be used in the zero-loss mode to remove all inelastically scattered electrons. Thicker amorphous and crystalline specimens can be observed without chromatic aberration and with a transmissionof 10−3 up to 80(110) and 150(200) μg/cm2 at 80(120) keV, respectively. This results in a condiserable increase of scattering, phase and Bragg contrast, especially for low Z material because the ratio of inelastic-to-elastic cross section increases as 20/Z with decreasing atomic number. In future energy-filtered high-resolution crystal-lattice images will offer us a better comparison with dynamical simulations. Plasmon loss filtering can be applied for a better separation of phases (e.g. precipitates in a matrix), which differ in their plasmon loss by about 1 eV. Owing to intersections of the energy loss spectra, different parts of a specimen can change their contrast when tuning the selected energy window. Structures containing non carbon atoms will beconsiderably increased in a bright field like contrast relative to the carboneous matrix just below the carbon K edge (structure—sensitive imaging).

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ZHU Zhi-xiong, 朱志雄, 曾祥楷 ZENG Xiang-kai, 刘全顺 LIU Quan-shun, and 陈阳 CHEN Yang. "Power-spectrum-based Method of Identifying Rotational Direction in Remote Angular-velocity Measurement with Spatial Filtering Technique." ACTA PHOTONICA SINICA 44, no. 7 (2015): 712005. http://dx.doi.org/10.3788/gzxb20154407.0712005.

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Bakenfelder, A., L. Reimer, and R. Rennekamp. "Comparison of Images of Crystalline Specimens by Energy-Filtering TEM at 80 keV and CTEM at 200 keV." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 62–63. http://dx.doi.org/10.1017/s0424820100133904.

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One advantage of energy-filtering electron microscopy (EFEM) is to avoid the chromatic aberration of conventional transmission electron microscopy (CTEM) by the mode of electron spectroscopic imaging (ESI) using either zero-loss filtering of unscattered and elastically scattered electrons or a narrow selected energy window at the most probable loss of the electron-energy-loss spectrum (EELS). Chromatic aberration can also be reduced by high-voltage electron microscopy (HVEM). Comparisons of ESI at 80 keV and CTEM at 200 keV have already been reported for biological tissues. In this contribution we compare the imaging of evaporated crystalline films with ESI at 80 keV in a ZEISS EM902 and with CTEM at 200 keV in a Hitachi H800/NA.Zero-loss filtering at 80 keV can be applied for maximum mass-thicknesses of x=ρt≃150 μg/cm2 where the zero-loss transmission falls below 0.001 and an energy window at the most-probable energy loss can be used below ≃300 μg/cm2. Inelastic scattering preserves the Bragg contrast.

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Su, Deer, Xinwei Wang, Guanyu Shang, Xumin Ding, Shah Nawaz Burokur, Jian Liu, and Haoyu Li. "Amplitude-phase modulation metasurface hologram with inverse angular spectrum diffraction theory." Journal of Physics D: Applied Physics 55, no. 23 (March 9, 2022): 235102. http://dx.doi.org/10.1088/1361-6463/ac5699.

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Abstract Designed metasurfaces, composed of a two-dimensional array of meta-atoms, provide an alternative approach to achieving efficient electromagnetic wave manipulation. Metasurface holography is an emerging and promising imaging technology, with improved image quality and spatial resolution compared to traditional holography. Many devices are fabricated only by coding specific phase responses of the designed metasurfaces. However, the modulation of both the amplitude and phase responses of electromagnetic waves can significantly improve the quality of the holographic image. In this paper, we employ bi-layered split rings as meta-atoms, which can fully control the transmission amplitude and phase independently. Furthermore, we present an algorithm based on the inverse angular spectrum diffraction theory to obtain the amplitude and phase information for the shape and arrangement of the meta-atoms. The proof-of-concept experiments in the microwave regime demonstrate that the inverse angular spectrum diffraction theory shows better image quality than the conventional Gerchberg-Saxton algorithm, especially when the number of meta-atoms is the same or even slightly fewer. The proposed approach provides an innovative and effective method for hologram design and expands the route to versatile applications related to holographic technologies.

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Ma, Qian, and Hengkai Zhao. "Capacity of a Radio Vortex Communication System Using a Partial Angular Aperture Receiving Scheme under the Horizontal Non-Kolmogorov Model." Sensors 21, no. 5 (March 4, 2021): 1778. http://dx.doi.org/10.3390/s21051778.

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A partial receiving scheme based on limited angular aperture multi-beam receiving and demultiplexing can solve the difficulty caused by the divergence of the vortex beam in the conventional whole beam receiving scheme and realize the long-distance transmission of the vortex wave. The propagation of the radio vortex beam in atmospheric turbulence is of significant importance in theoretical study and practical applications. In this paper, the influence of atmospheric turbulence on the performance of a radio vortex (RV) communication system based on a partial angular aperture receiving (PAAR) scheme under the horizontal non-Kolmogorov channel model is studied. The spiral spectrum of the PAAR scheme and the channel capacity of the RV communication system using the PAAR scheme are derived. Simulation results demonstrate that the selected transmission frequency range has a great influence on the RV communication system based on the PAAR scheme, and the choice of the orbital angular momentum (OAM) mode number L has an influence on the propagation distance. The capacity of RV communication systems based on the PAAR scheme increases with the increase of the transmission frequency in the selected transmission frequency range of 10 GHz–60 GHz. When the number of orbital angular momentum (OAM) modes L is small, we can improve the signal-to-noise ratio (SNR) to obtain a larger capacity of the RV communication system based on the PAAR scheme over a longer propagation distance.

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Maleckl, Marek. "Energy filtering TEM of transfected DNA." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 924–25. http://dx.doi.org/10.1017/s0424820100167081.

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Energy filtering transmission electron microscopy (EFTEM) relies upon spatial separation of imaging electrons based upon their energy within an energy loss spectrum (Ottensmeyer 1986). In particular, EFTEM allows contrast enhancement in the zero loss mode and element mapping with electron spectroscopic imaging.These capabilities find a new application in studies of transgenesis in which constructs, probes, and antibodies are marked with organometallic clusters. Since the basic routes of intracellular trafficking of the transfected DNA have become recognized along with the crucial role played by nuclear pores as the selection gates (Malecki et al., 1995, Malecki and Skowron 1995),the current research is pursued by means of ultramicroscopy.Two strategies were developed for ultrastructural imaging of the transfected plasmid DNA with EFTEM. In both strategies, the transfected cells were cryo-immobilized, embedded in Lowlcryl K4M, and sectioned;plasmid constructs, transfection complexes containing nuclear localization signals, and transfection procedures were described previously (Malecki 1995).In the first strategy, the plasmid DNA was covalently conjugated to Nanogold (Nanoprobes) prior to transfections.

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Fotino, Mircea. "Chromatic imaging effects in hvem: an avenue to partial energy filtering." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 828–29. http://dx.doi.org/10.1017/s042482010010620x.

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In transmission electron microscopy the normal image is formed by elastic and inelastic electrons that have interacted with the specimen. Their relative contributions to image formation depend on beam accelerating voltage and on angular acceptance determined by the objective-lens aperture.Inelastic scattering occurs primarily within small scattering angles while elastic scattering extends to wider angles. Consequently, the beam accepted by small objective-lens apertures contains a higher proportion of inelastic electrons than the beam accepted by larger apertures. By varying the size of the objective-lens aperture it is thus possible to modify the composition of the imaging beam and thereby the image quality: better resolution and higher image quality are obtained with larger apertures. It is necessary, however, to make sure that the acceptance angle is both larger than the lower limit imposed by diffraction and smaller that the upper limit imposed by spherical aberration.

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Hughes, Daniel, and Karl Michael Schmidt. "Absolutely continuous spectrum of Dirac operators with square-integrable potentials." Proceedings of the Royal Society of Edinburgh: Section A Mathematics 144, no. 3 (May 16, 2014): 533–55. http://dx.doi.org/10.1017/s0308210512001187.

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We show that the absolutely continuous part of the spectral function of the one-dimensional Dirac operator on a half-line with a constant mass term and a real, square-integrable potential is strictly increasing throughout the essential spectrum (−∞, −1] ∪ [1, ∞). The proof is based on estimates for the transmission coefficient for the full-line scattering problem with a truncated potential and a subsequent limiting procedure for the spectral function. Furthermore, we show that the absolutely continuous spectrum persists when an angular momentum term is added, thus also establishing the result for spherically symmetric Dirac operators in higher dimensions.

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CHEN, HAIYAN. "EFFECT OF TRANSMISSION FUNCTION OF CASCADED MULTILAYER MEDIUM THIN FILM FILTER ON Er–Yb CO-DOPED WAVEGUIDE AMPLIFIERS." International Journal of Modern Physics B 25, no. 17 (July 10, 2011): 2371–77. http://dx.doi.org/10.1142/s0217979211101144.

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Modeling and amplification of erbium–ytterbium co-doped phosphate glass waveguide amplifier with a cascaded multilayer medium thin film filter is investigated theoretically. This proposed filter consists of some different filtering unit cells with different central wavelength and bandwidth, and each cell can suppress certain peak gain at a specific wavelength. The intrinsical gain spectrum of amplifier is obtained by solving a set of rate and power propagation equations, the effect of transmittance spectrum of thin film filter on flattening gain is discussed, and the transmission function of cascaded multilayer medium thin film filter is obtained.

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Pavelyev, A. G., and A. A. Pavelyev. "The duality principle and new forms of the inverse Laplace transform for the analysis of signal propagation in inhomogeneous media with dispersion." Доклады Академии наук 489, no. 6 (December 23, 2019): 558–63. http://dx.doi.org/10.31857/s0869-56524896558-563.

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New equations for Laplace transform inversion are obtained. The equations satisfy the causality principle. The impulse response of a channel is determined in order to analyze dispersion distortions in inhomogeneous media. The impulse response excludes the possibility that the signal exceeds the speed of light in the medium. The transmission bandwidth, the angular spectrum, and the Doppler shift in the ionosphere are computed.

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Hunt, J. A., and R. H. Harmon. "EFTEM and STEM EELS Spectrum Imaging." Microscopy and Microanalysis 4, S2 (July 1998): 152–53. http://dx.doi.org/10.1017/s1431927600020882.

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Electron energy-loss spectroscopy (EELS) in the transmission electron microscope (TEM) is a powerful technique that analyzes the inelastic scattering distribution of the fast TEM electrons after they have lost energy within the sample. The resultant energy-losses are characteristic of elemental, chemical, and dielectric properties and are typically measured in one of two ways. Parallel-detection EELS spectrometers (PEELS) acquire spectral data over a large range of energy-loss simultaneously for rapid acquisition of spectral data at a single point. In contrast, the energy filtering TEM (EFTEM) acquires only a single energy band at once, but does so for thousands or even millions of image pixels simultaneously.Spectrum-imaging concerns the acquisition of spectroscopic data of sufficient detail for rigorous analysis at each pixel in a digital image. (Fig. 1) A STEM EELS spectrum image “data cube” can be acquired by stepping a focused electron probe to each pixel and filling the spectrum image one spectrum at a time.

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Watanabe, M., and F. Allen. "Development of a New Acquisition Scheme for Energy-Filtering Transmission Electron Microscopy Spectrum-Imaging toward Quantification." Microscopy and Microanalysis 17, S2 (July 2011): 790–91. http://dx.doi.org/10.1017/s143192761100482x.

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Zhang, Jialin, Xuanyi Yu, Jingxin Dong, Weiji Yang, Shuang Liu, Chongyang Shen, Jiacheng Duan, and Xiaoxu Deng. "A Plasmonic Infrared Multiple-Channel Filter Based on Gold Composite Nanocavities Metasurface." Nanomaterials 11, no. 7 (July 14, 2021): 1824. http://dx.doi.org/10.3390/nano11071824.

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A plasmonic near-infrared multiple-channel filter is numerically and experimentally investigated based on a gold periodic composite nanocavities metasurface. By the interference among different excited plasmonic modes on the metasurface, the multipeak extraordinary optical transmission (EOT) phenomenon is induced and utilized to realize multiple-channel filtering. Investigated from the simulated transmission spectrum of the metasurface, the positions and intensity of transmission peaks are tuned by the geometrical parameters of the metasurface and environmental refractive index. The fabricated metasurface approached transmission peaks at 1128 nm, 1245 nm, and 1362 nm, functioning as a three-passbands filter. With advantages of brief single-layer fabrication and multi-frequency selectivity, the proposed plasmonic filter has potential possibilities of integration in nano-photonic switching, detecting and biological sensing systems.

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INOUE, T. "Theory of Transmission and Dissipation of Radiation near a Metallic Slab Based on Angular Spectrum Representation." IEICE Transactions on Electronics E88-C, no. 9 (September 1, 2005): 1836–44. http://dx.doi.org/10.1093/ietele/e88-c.9.1836.

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Tong, Xiao Rong. "Research on the White Noise Suppression by Adaptive Filtering of Genetic Algorithm." Applied Mechanics and Materials 155-156 (February 2012): 989–94. http://dx.doi.org/10.4028/www.scientific.net/amm.155-156.989.

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Signal transmission is often subject to the disturbance of white noise. Owing to the spectrum of white noise can be found in the real number field, it is often difficult to filter out with the traditional filter. This article describes the methods of white noise suppression using adaptive filter and mean filter. First, using the genetic algorithm to optimize the weight vector of the adaptive filter, and then using the method of the mean filter to further filter, Simulation results show that the filter can effectively suppress white noise.

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Liu, Ning, and Thomas Schumacher. "Improved Denoising of Structural Vibration Data Employing Bilateral Filtering." Sensors 20, no. 5 (March 5, 2020): 1423. http://dx.doi.org/10.3390/s20051423.

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With the continuous advancement of data acquisition and signal processing, sensors, and wireless communication, copious research work has been done using vibration response signals for structural damage detection. However, in actual projects, vibration signals are often subject to noise interference during acquisition and transmission, thereby reducing the accuracy of damage identification. In order to effectively remove the noise interference, bilateral filtering, a filtering method commonly used in the field of image processing for improving data signal-to-noise ratio was introduced. Based on the Gaussian filter, the method constructs a bilateral filtering kernel function by multiplying the spatial proximity Gaussian kernel function and the numerical similarity Gaussian kernel function and replaces the current data with the data obtained by weighting the neighborhood data, thereby implementing filtering. By processing the simulated data and experimental data, introducing a time-frequency analysis method and a method for calculating the time-frequency spectrum energy, the denoising abilities of median filtering, wavelet denoising and bilateral filtering were compared. The results show that the bilateral filtering method can better preserve the details of the effective signal while suppressing the noise interference and effectively improve the data quality for structural damage detection. The effectiveness and feasibility of the bilateral filtering method applied to the noise suppression of vibration signals is verified.

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Wang, Yi Hua, Lin Bao, and Hai Ming Jin. "A Method Research to Obtain Quickly the Vibration Transmissibility of Cushioning Packaging Materials." Advanced Materials Research 542-543 (June 2012): 87–90. http://dx.doi.org/10.4028/www.scientific.net/amr.542-543.87.

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Through the data acquisition system of drop impact test impact excitation pulse and in response to a pulse, to reduce or eliminate the experimental process generated interference signal brought influence, the excitation and response signals are Fourier transform (FFT), get the cushing material power spectrum and cross spectrum density value, the time domain signal into frequency domain signal, realize the effective filtering, the frequency domain signal in each frequency through the transfer rate calculation formula of cushing packaging material transient vibration transmitting rate, the transmission rate of the way the process of obtaining description and theoretical analysis.

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Reimer, L., R. Rennekamp, and A. Bakenfelder. "Electron spectroscopic imaging of thick crystalline specimens." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 412–13. http://dx.doi.org/10.1017/s0424820100154032.

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Electron spectroscopic imaging (ESI) by an energy-filtering electron microscope (EFEM, Zeiss EM902) shows the following advantages when compared with the unfiltered bright-field mode:1.The zero-loss image does not contain the contribution of inelastically scattered electrons. Though plasmon scattering shows a conversation of Bragg contrast - edge and bent contours and lattice defect images -, the angular distribution of inelastically scattered electrons results in a broader spectrum of excitation errors and a blurring of Bragg contrast.2.The zero-loss image avoids the chromatic aberration of inelastically scattered electrons for medium specimen thicknesses and can be applied so long as the intensity of the zero-loss peak in the electron energy-loss spectrum (EELS) is high enough for an exposure in a reasonable time (<100 s).3.Thick specimens with negligible zero-loss intensity can be imaged with an energy window at the highest multiple plasmon loss of the Poisson distribution or at the most probable energy of a Landau distribution. The angular distribution of electrons with these energy losses is so broad that the Bragg contrast is blurred, and the contrast is only caused by anomalous absorption effects similar to multi-beam images in the STEM mode when using a large probe aperture.

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Deng, Xuesong, Li Cheng, Jiaming Shi, Ming Fang, Zongsheng Chen, Zhigang Li, Yahui Wang, and Xiangyin Lv. "Transmission and backscattering characteristics of electromagnetic waves in single layer combined plasma array." Journal of Physics D: Applied Physics 55, no. 19 (February 14, 2022): 195201. http://dx.doi.org/10.1088/1361-6463/ac5146.

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Abstract Manipulation of electromagnetic (EM) waves is essential for various microwave applications. This research studies the modulation of EM waves by using single-layer plasma arrays consisting of discharge tubes. We experimentally investigate the transmission spectra and backscattering attenuation characteristics of the plasma arrays, and numerical simulations further reveal the modulation mechanism and influences of the plasma arrays. The experimental and numerical results show that broadband tunable photonic bandgaps can be achieved in frequency ranges of 4–7.5 GHz and 7–9.5 GHz for the transmission spectrum and the backscattering spectrum, respectively. In addition, the proposed plasma array can achieve different modulation effects to satisfy the corresponding scenario requirements by adjusting the configuration and parameters such as the plasma frequency, spacing of the plasma tubes, and the discharge tube’s excitation or extinction of the plasma array. The wave manipulation of the combined plasma array creates opportunities for developing numerous applications, including large-area spatial filtering, radar stealth, and reconfigurable antennas.

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Andrews, S. B., J. Hongpaisan, N. B. Pivovarova, D. D. Friel, and R. D. Leapman. "Mapping the Subcellular Distribution of Calcium in Depolarized Neurons by Electron Energy Loss Spectrum Imaging." Microscopy and Microanalysis 6, S2 (August 2000): 162–63. http://dx.doi.org/10.1017/s1431927600033304.

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In the context of biological specimens, it is in principle desirable to quantitatively map, rather than just point analyze, the distribution of physiologically important elements, and to do so at subcellular resolution. Presently, this can be accomplished by electron energy loss spectrum-imaging (EELSI) in both the scanning transmission electron microscope (STEM) and the energy-filtering transmission electron microscope (EFTEM). Until recently, this approach has been of limited value for mapping the particularly important element Ca, mainly because intracellular total Ca concentrations are normally quite low (<5 mmol/kg dry weight) and because the background in the vicinity of the Ca L23 edge is complex and requires precise background modeling to extract the very weak Ca signals. As a result, the Ca signal is usually not high enough to reach detection threshold during a practical EELSI acquisition time.

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KEPPENNE, CHRISTIAN L., and MICHAEL GHIL. "ADAPTIVE FILTERING AND PREDICTION OF NOISY MULTIVARIATE SIGNALS: AN APPLICATION TO SUBANNUAL VARIABILITY IN ATMOSPHERIC ANGULAR MOMENTUM." International Journal of Bifurcation and Chaos 03, no. 03 (June 1993): 625–34. http://dx.doi.org/10.1142/s0218127493000520.

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Principal component analysis (PCA) in the space and time domains is applied to filter adaptively the dominant modes of subannual (SA) variability of a 12-year long multivariate time series of Northern Hemisphere atmospheric angular momentum (AAM); AAM is computed in 23 latitude bands of equal area from operational analyses of the U.S. National Meteorological Center. PCA isolates the leading empirical orthogonal functions (EOFs) of spatial dependence, while multivariate singular spectrum analysis (M-SSA) yields filtered time series that capture the dominant low-frequency modes of SA variability. The time series prefiltered by M-SSA lend themselves to prediction by the maximum entropy method (MEM). Whole-field predictions are made by combining the forecasts so obtained with the leading spatial EOFs obtained by PCA. The combination of M-SSA and MEM has predictive ability up to about a month. These methods are essentially linear but data-adaptive. They seem to perform well for short, noisy, multivariate time series, to which purely nonlinear, deterministically based methods are difficult to apply.

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Soler, Mireille, Sophie Desplat-Jego, Béatrice Vacher, Laurence Ponsonnet, Marc Fraterno, Pierre Bongrand, Jean-Michel Martin, and Colette Foa. "Adhesion-related glycocalyx study: quantitative approach with imaging-spectrum in the energy filtering transmission electron microscope (EFTEM)." FEBS Letters 429, no. 1 (June 5, 1998): 89–94. http://dx.doi.org/10.1016/s0014-5793(98)00570-5.

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He, Xing, Zhong-Zhou Tian, Shuai Wang, Ping Yang, and Bing Xu. "Optical field propagation model of ring-down cavity light field based on angular spectrum propagation theory and evaluation criterion of cavity tuning." Acta Physica Sinica 72, no. 1 (2022): 014205. http://dx.doi.org/10.7498/aps.72.20221530.

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In cavity ring-down technique, cavity maladjustment has an essential effect on the measurement of intracavity loss. Several adjustment criterions have been adopted to achieve the optimal cavity state. However, experimental study shows that these criterions may correspond to different cavity states, which means that there is discrepancy between different criterions. In view of this problem, a model of intracavity propagation of Gaussian beam is established based on the angular spectrum propagation theory. This model is tested by numerical simulation and experimental research together. In the simulation, the true value of intracavity loss can be known beforehand. The two-dimensional angular scanning is carried out for certain cavity mirror. The two-dimensional distributions of the measure value of intracavity loss and the transmission light intensity are obtained simultaneously. These distributions are both nonlinear and multi-extremum, which will doubtlessly increase the difficulty in realizing the cavity adjustment. By comparing the distributions , we do find the discrepancy between the largest transmission light intensity and the least measured intracavity loss. Meanwhile both of these two states may be not corresponding to the true value in fact. After statistical studies, the relative error of the least measured intracavity loss is -37.01±11.79 ppm, whereas the relative error of the largest transmission intensity is –2.70±0.89 ppm. The criterion of the largest transmission intensity shows better stability and repeatability. This model is further tested in a folded cavity ring-down setup. The similar scanning procedure is carried out. A major problem in the experiment is that the true value of intracavity loss cannot be known. So only the repeatability precision of the measured intracavity loss can be analyzed. The statistical results of the largest light intensity and the least measured intracavity loss are ± 29.32 ppm and ± 70.71 ppm, respectively. The criterion of the largest transmission intensity has better repeatability, which is basically consistent with the simulation result. In this way the rationality of this model can be verified to some degree. In this paper, the criterion of the largest transmission intensity is recommended in the cavity ring-down technique. Furthermore, this model can be a reference for the research of intracavity optical field response, intracavity optical field transmission, unstable resonator alignment, etc.

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Zhong, Jian Jun, Sheng Nan Fang, and Chang Ying Linghu. "Research on Application of Wavelet Denoising Method Based on Signal to Noise Ratio in the Bench Test." Applied Mechanics and Materials 457-458 (October 2013): 1156–62. http://dx.doi.org/10.4028/www.scientific.net/amm.457-458.1156.

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During the tests of the vehicle automatic transmission bench, the acceleration signal is needed to be denoised. As a means of denoising, wavelet threshold denoising method has small amount of calculation and better filtering effect. However, adopting different wavelet basis functions as well as different threshold rules might have a direct effect on the signal denoising. In this paper, we firstly construct the simulated noisy signal approximated to the observed signal, and then do the signal denoising experiment of parameter matching. Secondly, seven Symlets wavelet basis functions and four classical wavelet threshold rules are selected and tested one by one. Signal to noise ratio (SNR) and root mean square error (RMSE) of the denoised signal, the evaluation indicators, are calculated and carried out in accordance with the merits of denoising effect. Thus the optimal combination of the fixed threshold rule and sym8 wavelet basis function is obtained. Finally, this combination is used in the bench test to denoise the angular acceleration signal, and good filtering effect is achieved.

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Novikov, I. "Big Bang Scenario and Nature of Dark Matter." Symposium - International Astronomical Union 168 (1996): 289–300. http://dx.doi.org/10.1017/s0074180900110174.

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We give a brief review of a problem of dark matter in the Universe. The key questions regarding dark matter are discussed: what is the distribution of dark matter at different scales? What is the nature of dark matter? Is there baryonic dark matter? We discuss a few new techniques of the investigation of dark matter in the Universe. We discuss the peculiar periodic dependence of the initial spectrum of the baryonic matter distribution on wavelength at the moment of recombination (Sakharov oscillations). Sakharov oscillations should manifest themselves by the specific anomalies in the angular correlation function of the microwave background anisotropy on scales 10′ – 2°, practically in any cosmological model. We discuss special methods for filtering of this effect in the observational data.

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Zhao, De Zun, Wei Dong Cheng, Wei Gang Wen, and Yang Liu. "Fault Feature Extraction Method of the Rolling Element Bearing Based on Reverse Order Tracking." Key Engineering Materials 693 (May 2016): 1361–70. http://dx.doi.org/10.4028/www.scientific.net/kem.693.1361.

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When dealing with the vibration analysis of the rolling element bearing under gear noise and time-varying speed condition, order tracking is always utilized to convert the time signal to angular domain. In this way, the smearing effect in the spectrum is avoided and the noise cancellation methods based on the periodicity of the gear signal can be reapplied. In this paper, the resonance frequency variation of the resampled signal is analyzed and its influence on the kurtogram algorithm based bandpass filtering procedure is studied through a simulation experiment and a fault feature extraction method of the rolling bearing based on reverse order tracking is proposed. Effectiveness of the proposed method is verified through the analysis of the signal measured from the test-rig.

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Freiherr von Künßberg, René, Herbert Plischke, and Werner Eisenbarth. "Blaulichtfilter und deren Auswirkung auf den Pupillenlichtreflex." Optometry & Contact Lenses 2, no. 3 (March 30, 2022): 99–107. http://dx.doi.org/10.54352/dozv.epuu2545.

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Purpose. The increasing exposure to artificial blue light sources has spawned an equal interest in spectacle lenses that protect against this potentially harmful proportion of light. This study compared the performance of different blue light filtering spectacle lenses and investigated whether a reduction in blue light transmission affects light-dependent physiological processes. Material and Methods. The wavelength-specific transmission of various spectacle lenses was determined by spectrometer and the influence of the lenses on the PIPR (Post Illumination Pupil Response) was evaluated. Thirty-six eyes of 18 adults (20 - 30 years) were measured by monocular, direct chromatic pupillometry with and without blue light filtering lenses. The modified pupillometer (PupilX from Albomed GmbH) with red and blue stimulation was used with a pupil exposure time of 30 seconds (darkness: 1 s; light stimulus: 1 s; darkness: 28 s). Results. In the main action spectrum of the blue light hazard (400 nm ≤ λ ≤ 500 nm), the transparent blue light filter showed lower absorption compared to “comfort- and wellness” lenses of filter category 1 (absorption: 19.60 % to 25.27 % and 65.04 % to 97.43 %). In the early and late phase of the post illumination pupil reflex (PIPR) after a blue light stimulus, we detected a significantly smaller area under the curve (p < 0.001), a larger normalized pupil diameter (p < 0.001), and a larger curvature index in an exponential interpolation (p < 0.001) when the “comfort- and wellness-” lenses were used. Conclusion. Blue light filtering lenses have been shown to reduce the transmission of blue light and thus can minimize the risk of blue light exposure. By simultaneously reducing the stimulation of intrinsic photosensitive retinal ganglion cells (ipRGCs), light-modulated physiological processes such as circadian regulation could be altered. The use of “comfortand wellness” lenses showed a significant change in the PIPR. An influence by transparent, blue-light filtering spectacle lenses could not be detected. Keywords Blue light filtering spectacle lenses, blue light hazard, chromatic pupillometry, intrinsically photosensitive retinal ganglion cells, circadian rhythm

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Zhu, Jun, and Jian Lou. "Ultrasensitive and Multifunction Plasmonic Temperature Sensor with Ethanol-Sealed Asymmetric Ellipse Resonators." Molecules 23, no. 10 (October 19, 2018): 2700. http://dx.doi.org/10.3390/molecules23102700.

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In order to improve the low temperature sensitivity of conventional sensors, a plasmonic multifunction temperature sensor with high sensitivity is proposed and investigated systematically in this paper. The sensor consists of two metal layers and two ethanol-sealed elliptical resonators connected to a straight waveguide by two rectangular tubes. We numerically analyzed the transmission characteristics of the Nano-device to assess its performance with the finite element method and achieved great optical properties. The results show that an obvious blue shift of the transmission spectrum appears by varying temperatures, exhibiting a great sensing effect. Sensitivity of the sensor reaches −3.64 nm/°C, far greater than conventional temperature sensors. Our research also demonstrates that the transmission spectrum could be modulated efficiently by the ratio of semi-short axis to semi-major axis of the ellipse resonators and the width of two same rectangular tubes. Furthermore, the Nano-device has a filtering characteristic. The transmittances of pass-band and stop-band are 96.1% and 0.1%, respectively. The results of this study can pave the way for low-cost sensing application in high-density photonic circuits and biosensors.

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Kothleitner, G., and H. A. Brink. "Spectroscopy and Imaging With Energy-Filtering Tems: Parameters That Matter." Microscopy and Microanalysis 6, S2 (August 2000): 158–59. http://dx.doi.org/10.1017/s1431927600033286.

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Spectroscopy and imaging techniques based on electron energy-losses (EELS), which are accessible through energy-filtering transmission electron microscopes (EFTEMs), have proven to be important tools in both materials and life science investigations.The two most widely used techniques on commercially available EFTEMs are elastic imaging and elemental mapping. Elastic imaging enhances image resolution and contrast by extracting the zero-loss signal and eliminating the inelastic background, whereas elemental mapping, which involves signals coming from element-specific inner-shell ionization edges, is employed to form two dimensional elemental distribution images. In both cases relatively large energy windows of a range of 10 to 30eVare typically used to form energy-filtered images with usually low to moderately high magnifications.There is however much more information available in an EELS spectrum, which is contained in the detailed fine structure within 0-20eV of a core excitation edge (ELNES) or in the very low energy-loss up to 5eV.

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Kothleitner, G., F. Hofer, and C. Trevor. "Difference Spectrum Images: Numerical Filters Applied to EELS 3D Data Sets." Microscopy and Microanalysis 7, S2 (August 2001): 1160–61. http://dx.doi.org/10.1017/s1431927600031871.

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Spectroscopy and imaging techniques based on electron energy-losses (EELS) in a TEM have proven to be important tools to characterize materials and life science samples. There are two techniques available to explore the energy-loss dimension. in the fixed-beam approach spectroscopic data are recorded via energy-filtered images taken by an energy-filtering transmission electron microscope (EFTEM). in the STEM approach a parallel-detection EELS spectrometer (PEELS) coupled with a small focused probe acquires large energy ranges of the energy-loss spectrum point-wise for a small area. Both techniques produce complete 3 dimensional data sets containing energy-loss information for all image pixels. This technique is called EFTEM or STEM spectrum imaging.In the recorded SI data cube the x and y-axes correspond to spatial positions in the specimen as for any image. The third axis contains the energy-loss spectrum. in the scanning mode one records a complete spectrum for each pixel.

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Choi, Jeongseok, Taeyoung Kim, Jaekwon Kim, Sunghwan Moon, Youngshin Han, and Jongsik Lee. "Data collection model in hybrid network for participatory sensing." International Journal of Modeling, Simulation, and Scientific Computing 07, no. 04 (December 2016): 1643002. http://dx.doi.org/10.1142/s1793962316430029.

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Advances in mobile technology make most people have their own mobile devices which contain various sensors such as a smartphone. People produce their own personal data or collect surrounding environment data with their mobile devices at every moment. Recently, a broad spectrum of studies on Participatory Sensing, the concept of extracting new knowledge from a mass of data sent by participants, are conducted. Data collection method is one of the base technologies for Participatory Sensing, so networking and data filtering techniques for collecting a large number of data are the most interested research area. In this paper, we propose a data collection model in hybrid network for participatory sensing. The proposed model classifies data into two types and decides networking form and data filtering method based on the data type to decrease loads on data center and improve transmission speed.

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Journal articles on the topic 'ANGULAR FILTERING IN TRANSMISSION SPECTRUM'

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