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1
Hussain, Ghasan Ali. "DESIGN OF PARALLEL COUPLED MICROSTRIP BAND-PASS FILTER." INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 15, no. 5 (April 21, 2016): 6768–75. http://dx.doi.org/10.24297/ijct.v15i5.1650.
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Filters occupy important acts in several Radio Frequency microwave applications. Several applications such as wireless communications still challenge RF/microwave filters with strict requirements such as smaller size, higher performance, lighter weight, and lower cost. Microstrip Filters for RF/Microwave Applications offers a unique and comprehensive treatment of RF/microwave filters based on the microstrip structure. One of the most common methods in designing microwave filters is using of parallel-coupled microstrip. In this paper simulate and fabricate by using Ansoft Designer a two resonator microstrip band-pass filter suitable for Wi-Fi applications. The results of simulation were quite good.
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Gohil, Bhumikaba, and Khyati Chavda. "Design & Simulation of S Band Planar Microwave Filter for Wireless Application." IOP Conference Series: Materials Science and Engineering 1187, no. 1 (September 1, 2021): 012016. http://dx.doi.org/10.1088/1757-899x/1187/1/012016.
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Abstract Reducing the size of today’s wireless communication systems has become an important criterion in filter design with minimal possible value of filter parameters. To achieve this goal in wireless communication system, filter design is the most important part of the signal transmission process. Conventional filters are very important for modern wireless communication systems as they do not provide the desired miniaturization and results. Recently, using metamaterials and dielectric resonators, the filter size has been drastically reduced to a very small size for practical applications. This filter is flat and lightweight. It consumes very low power consumption. In this proposed work, a compact S-band microwave band stop filter was designed using a simple technique. These filters are small in size and light in weight. The design covers the S-band and is suitable for the desired frequency for Wi – Fi and wireless LAN application.
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Lubey, Daniel P., and Todd A. Ely. "Anomaly Detection in Autonomous Deep-Space Navigation via Filter Bank Gating Networks." Applied Sciences 12, no. 21 (November 3, 2022): 11161. http://dx.doi.org/10.3390/app122111161.
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This study investigates methods for autonomous navigation of a deep-space spacecraft where one-way radiometric and on-board optical information are fused to create a fully informed state estimate. The specific focus is on using filter bank methods (i.e., Multiple Model Estimation [MME] and Mixture of Experts [MoE]) to detect when measurement and/or dynamical mis-modeling occurs. We develop a new χ2-based gating network for a filter bank that may be used to identify poorly performing filters (i.e., those with low weights), which may be used as a signal for mis-modeling in the system. In addition to defining and deriving this new weighting scheme, numerical simulations based on NASA’s InSight mission demonstrate this new algorithm’s performance with and without measurement and dynamical mis-modeling present.
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Shieh, Chun-Ping, Shih-Hung Yang, Yu-Shun Liu, Yun-Ting Kuo, Yu-Chun Lo, Chao-Hung Kuo, and You-Yin Chen. "Simultaneously Spatiospectral Pattern Learning and Contaminated Trial Pruning for Electroencephalography-Based Brain Computer Interface." Symmetry 12, no. 9 (August 20, 2020): 1387. http://dx.doi.org/10.3390/sym12091387.
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Electroencephalography (EEG)-based brain computer interfaces (BCIs) translate motor imagery commands into the movements of an external device (e.g., a robotic arm). The automatic design of spectral and spatial filters is a challenging task, as the frequency bands of the spectral filters must be predefined by previously published studies and given that they may be affected during trials by artifacts and improper motor imagery (MI). This study aimed to eliminate the contaminated trials automatically during classifier training, and to simultaneously learn the spectral and spatial patterns without the need for predefined frequency bands. Compared with previous studies that measured the discriminative power of a frequency band based on mutual information, this study determined the difference of the class conditional probability density function between two MI classes. This information was further shared to measure the contamination level of the trial that simplified the computation. A particle-based approximation technique iteratively constructed a filter bank that extracted discriminative features, and simultaneously removed potentially contaminated trials. The particle weight was estimated by an analysis of variance F-test instead of mutual information as commonly used in previous studies. The experimental results of a publicly available dataset revealed that the proposed method outperformed the other BCI in terms of the classification accuracy. Asymmetrical spatial patterns were found on left- versus right-hand MI classifications. The learnt spectral and spatial patterns were consistent with prior neurophysiological knowledge.
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Barmashe, Pravin, and D. K. Srivastava. "Design and Optimization of Tri-Band Open Loop Resonator Filter for BT, WiMAX, WLAN and Wi-Fi Applications." International Journal of Emerging Technology and Advanced Engineering 12, no. 4 (April 15, 2022): 181–89. http://dx.doi.org/10.46338/ijetae0422_22.
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The consumer wireless frequency spectrum is getting denser and overlapping so may signals can cause interference and less data speed. There is need to either switch to new channel or to use newer technologies available. As per FCC new 6GHz band is now open for WLAN & Wi-Fi networks and to filter out other signals a microwave filter could the best mate. This paper proposed a tri-band microstrip filter having rectangular resonator with open loop has been evaluated. Because of its tiny size, lighter weight, cheaper cost, and superior performance, microstrip filters are often chosen over lumped filters at higher frequencies. The construction, refinement, and implementation of a modular tri-band bandpass filter have examined in this research. The proposed low-profile tri-band MS filter with three resonators designed for BT, WiMAX, WLAN and Wi-Fi microwave applications. The physical size of the filter is 30×15 mm2 . The designed filter has full ground and substrate is of FR-4 material having 4.3 dialectic constant and 1.6 mm thickness. The filter is made of four rectangular resonators of diverse dimension. Resonators are arranged in symmetrical geometry. Proposed tri-band bandpass filter is having negative group delay which facilitates the feedforward amplifier circuits. Filters with NGD also helps to reduces the physical size of the microwave circuits. The proposed tri-band filter has passband characteristics on 2.37GHz, 5.36GHz, and 6.15GHz with the insertion loss of 1.03dB, 1.6dB, and 3.67dB having return loss of 23.3dB, 18.56dB, 12.8dB, and 21.87dB. Filter exhibits good fractional bandwidth of 21.92%, 6.68%, and 4.36% respectively. Proposed filter has 2 transmission zeros. The tested and simulated results of |S11| and |S21| parameters are quite identical which shows the excellent matching of physical parameters. Keywords - Tri-band, band-pass filter, NGD, rectangular resonators, BT, WiMAX, WLAN, Wi-Fi.
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Kumari, Poonam, Saif Ahamad, and Imran Ullah Khan. "FIR FILTER DESIGN WITH INERTIA WEIGHT AND COMPRESSION FACTOR APPROACH USING ADVANCED OPTIMIZATION TECHNIQUES." International Research Journal of Computer Science 8, no. 3 (March 31, 2021): 62–67. http://dx.doi.org/10.26562/irjcs.2021.v0803.004.
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This paper includes the design of Finite impulse response filter with inertia weight and compression factor approach. The objective function of filter design involves accurate control of various parameters of frequency spectrum and is thus highly non-uniform, non-linear, non-differentiable and multimodal in nature. Classical optimization methods cannot converge to solutions. Because they have disadvantages such as highly sensitive to starting points, frequent convergence to local optimum solution or divergence or revisiting the same solution, requirement of continuous and differentiable objective cost function, requirement of the piecewise linear cost approximation and problem of convergence and algorithm. Evolutionary optimization methods for the design of optimal digital filters have better control of parameters and the highest stop band attenuation.
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Mueller, Jaclyn A., Alexander I. Culley, and Grieg F. Steward. "Variables Influencing Extraction of Nucleic Acids from Microbial Plankton (Viruses, Bacteria, and Protists) Collected on Nanoporous Aluminum Oxide Filters." Applied and Environmental Microbiology 80, no. 13 (April 18, 2014): 3930–42. http://dx.doi.org/10.1128/aem.00245-14.
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ABSTRACTAnodic aluminum oxide (AAO) filters have high porosity and can be manufactured with a pore size that is small enough to quantitatively capture viruses. These properties make the filters potentially useful for harvesting total microbial communities from water samples for molecular analyses, but their performance for nucleic acid extraction has not been systematically or quantitatively evaluated. In this study, we characterized the flux of water through commercially produced nanoporous (0.02 μm) AAO filters (Anotop; Whatman) and used isolates (a virus, a bacterium, and a protist) and natural seawater samples to test variables that we expected would influence the efficiency with which nucleic acids are recovered from the filters. Extraction chemistry had a significant effect on DNA yield, and back flushing the filters during extraction was found to improve yields of high-molecular-weight DNA. Using the back-flush protocol, the mass of DNA recovered from microorganisms collected on AAO filters was ≥100% of that extracted from pellets of cells and viruses and 94% ± 9% of that obtained by direct extraction of a liquid bacterial culture. The latter is a minimum estimate of the relative recovery of microbial DNA, since liquid cultures include dissolved nucleic acids that are retained inefficiently by the filter. In conclusion, we demonstrate that nucleic acids can be extracted from microorganisms on AAO filters with an efficiency similar to that achievable by direct extraction of microbes in suspension or in pellets. These filters are therefore a convenient means by which to harvest total microbial communities from multiple aqueous samples in parallel for subsequent molecular analyses.
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Wang, Zhiyu, Yujian Shu, Siyuan Ma, Xi Guo, Wei Yang, Xu Ding, Xiaofeng Lyu, and Faxin Yu. "3D Heterogenous Integrated Wideband Switchable Bandpass Filter Bank for Millimeter Wave Applications." Electronics 12, no. 1 (December 30, 2022): 194. http://dx.doi.org/10.3390/electronics12010194.
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This article proposes a three-dimensional heterogenous-integrated (3DHI) switchable bandpass filter bank with two independent wideband filter channels that cover 26–40 GHz and 32.5–40 GHz, respectively. An accurate wafer-level process with a high hollowed ratio of the applied 8-inch high-resistivity-silicon (HR-Si) interposer wafers is presented to form both compact filter channels. Above the interdigital filter patterns fabricated on the bottom interposer wafer, deep cavities are etched in the cap interposer wafer to improve the quality factor of the filter bank. Besides the cavities, the cap interposer wafer is 35% hollow inside, which two bare dies of GaAs single-pole double-throw (SPDT) switches and two thin film resistors are attached to the bottom interposer after the wafer-to-wafer (W2W) bonding. To ensure good out-of-band performance, a 3D EM co-simulation of the switch layout at the chip level and filter patterns at the package level is applied. Measurement results show that the switchable filter bank achieves a high isolation of 50 dB and a competitive shape factor (BW30dB/BW3dB) of about 1.3. In addition, the size of the switchable filter bank is only 7.0 mm × 3.5 mm × 0.6 mm, and the weight is only 0.1 g.
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Dash, Dipak Kumar, and Pradip Kumar Sadhu. "A Review on the Use of Active Power Filter for Grid-Connected Renewable Energy Conversion Systems." Processes 11, no. 5 (May 12, 2023): 1467. http://dx.doi.org/10.3390/pr11051467.
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Renewable energy sources such as photovoltaic (PV) and wind energies are integrated into the grid due to their low global emissions and higher power conversion efficiency techniques. Grid-connected inverters are the core components of distributed generation networks. However, several harmonic current and voltage variations affect the performance of circuits in grid-connected networks. These issues can be easily resolved using passive filters, static vector generators, and dynamic energy filters (APFs). In higher-level units, the cost, dimensions, and weight of passive filters increase proportionally. The purpose of this research is to evaluate advanced APFs for reducing power switches and grid-connected weight, cost, and scale. Several studied APF inverter topologies, including single-phase, three-phase AC–AC, back-to-back, and common parameters, have been considered. Cost-effective solutions such as PV-based transformers based on APF, fewer inverters, multiple and multifunctional inverters, and wind-assisted conversion systems have been studied.
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Li, Lei, Margaret W. Frey, and Thomas B. Green. "Modification of Air Filter Media with Nylon-6 Nanofibers." Journal of Engineered Fibers and Fabrics 1, no. 1 (March 2006): 155892500600100. http://dx.doi.org/10.1177/155892500600100101.
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Nylon-6 fibers with average diameters below 500 nm were electrospun onto conventional air filter media at varying weight coverage levels using a multi-nozzle bank. The initial filtration efficiency of the air filter media was improved significantly with increasing coverage level and decreasing size of nylon-6 fibers. Nylon-6 fibers were very durable on the air filter media at the coverage level of 0.1 g/m2 due to the good adhesion with the air filter fibers. The production efficiency of the coated air filter media could be increased by using more nozzle banks for electrospinning without affecting the initial filtration efficiency of the air filter media significantly.
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Finster, P., J. Hollweg, and F. Seehofer. "Determination of Triacetin in Cigarette Filters by Pulsed Nuclear Magnetic Resonance Spectroscopy - Bestimmung von Triacetin in Zigarettenfiltern mit Hilfe der gepulsten Kernresonanzspektroskopie." Beiträge zur Tabakforschung International/Contributions to Tobacco Research 13, no. 5 (December 1, 1986): 255–64. http://dx.doi.org/10.2478/cttr-2013-0575.
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AbstractOur investigations show that pulsed nuclear magnetic resonance spectroscopy (p-NMR) is a suitable method of determining the triacetin content of freshly produced filter rods. The table-top pulse spectrometer tested in filter rod production distinguishes itself by the fact that it enables exact and reproducible direct measurements of whole filter rods to be made in seconds. There is no need for the whole process of preparing samples; after measurement the filters can be fed back into the production process. With the measuring method we have developed triacetin can be determined completely automatically, independent of sample weight and to a large extent independent of the moisture content of the filter material. The period of time between the triacetin application and the p-NMR measurement should be as short as possible and accurately reproducible.
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Barbu, Tudor. "Automatic Unsupervised Texture Recognition Framework Using Anisotropic Diffusion-Based Multi-Scale Analysis and Weight-Connected Graph Clustering." Symmetry 13, no. 6 (May 23, 2021): 925. http://dx.doi.org/10.3390/sym13060925.
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A novel unsupervised texture classification technique is proposed in this research work. The proposed method clusters automatically the textures of an image collection in similarity classes whose number is not a priori known. A nonlinear diffusion-based multi-scale texture analysis approach is introduced first. It creates an effective scale-space by using a well-posed anisotropic diffusion filtering model that is proposed and approximated numerically here. A feature extraction process using a bank of circularly symmetric 2D filters is applied at each scale, then a rotation-invariant texture feature vector is achieved for the current image by combining the feature vectors computed at all these scales. Next, a weighted similarity graph, whose vertices correspond to the texture feature vectors and the weights of its edges are obtained from the distances computed between these vectors, is created. A novel weighted graph clustering technique is then applied to this similarity graph, to determine the texture classes. Numerical simulations and method comparisons illustrating the effectiveness of the described framework are also discussed in this work.
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Robbiano, Valentina, Salvatore Surdo, Alessandro Minotto, Giancarlo Canazza, G. Mattia Lazzerini, Shabbir M. Mian, Davide Comoretto, Giuseppe Barillaro, and Franco Cacialli. "C-Si hybrid photonic structures by full infiltration of conjugated polymers into porous silicon rugate filters." Nanomaterials and Nanotechnology 8 (January 1, 2018): 184798041878840. http://dx.doi.org/10.1177/1847980418788404.
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Loading of one-dimensional (1-D) porous silicon photonic crystals (PS-PhCs), known as rugate filters, with luminescent materials is generally limited by the potential for (undesired) “pore clogging,” in relation to the size of the nanoparticles (e.g. quantum dots) or molecular species, and so far mainly restricted to small molecular weight materials or small nanocrystals, or in situ polymerized dyes. Here we report the infiltration 1-D PS-PhCs with a green-emitting commercial luminescent polymer (F8BT, poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)]), with a molecular weight of approximately 46 kDa across their whole depth (approximately 7.5 μm), thereby showing that pore clogging is not a concern for these structures. We also characterize the modification of the photoluminescence (PL) and decay rates, and investigate the detailed inner morphology of the filters with the help of (scanning) transmission electron microscopy. We observe both suppression (in the stop-band) and enhancement (at the high-energy band-edge) of the PL. We also find that the photonic stop-band is red-shifted after polymer infiltration, due to the increased effective refractive index of the polymer-infiltrated nanostructured system. The presence of just one unbroadened peak in the reflectance spectra after infiltration confirms that infiltration extends for the whole depth of the rugate filters.
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Pedzisz, Maciej, and Danilo P. Mandic. "A Homomorphic Neural Network for Modeling and Prediction." Neural Computation 20, no. 4 (April 2008): 1042–64. http://dx.doi.org/10.1162/neco.2008.12-06-418.
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A homomorphic feedforward network (HFFN) for nonlinear adaptive filtering is introduced. This is achieved by a two-layer feedforward architecture with an exponential hidden layer and logarithmic preprocessing step. This way, the overall input-output relationship can be seen as a generalized Volterra model, or as a bank of homomorphic filters. Gradient-based learning for this architecture is introduced, together with some practical issues related to the choice of optimal learning parameters and weight initialization. The performance and convergence speed are verified by analysis and extensive simulations. For rigor, the simulations are conducted on artificial and real-life data, and the performances are compared against those obtained by a sigmoidal feedforward network (FFN) with identical topology. The proposed HFFN proved to be a viable alternative to FFNs, especially in the critical case of online learning on small- and medium-scale data sets.
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Zhang, Dian, Bo Wang, and Qing Liang Qin. "A Portable Electroencephalogram Recording System for Rats." Applied Mechanics and Materials 577 (July 2014): 1236–40. http://dx.doi.org/10.4028/www.scientific.net/amm.577.1236.
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A wireless portable electroencephalogram (EEG) recording system for animals was designed, manufactured and then tested in rats. The system basically consisted of four modules: 1) EEG collecting module with the wireless transmitter and receiver (designed by NRF24LE1), 2) filter bank consisting of pre-amplifier, band pass filter and 50Hz trapper, 3) power management module and 4) display interface for showing EEG signals. The EEG data were modulated firstly and emitted by the wireless transmitter after being amplified and filtered. The receiver demodulated and displayed the signals in voltage through serial port. The system was designed as surface mount devices (SMD) with small size (20mm×25mm×3mm) and light weight (4g), and was fabricated of electronic components that were commercially available. The test results indicated that in given environment the system could stably record more than 8 hours and transmit EEG signals over a distance of 20m. Our system showed the features of small size, low power consumption and high accuracy which were suitable for EEG telemetry in rats.
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Zhao, Kunchen, and Dimitra Psychogiou. "Monolithically-integrated 3D printed coaxial bandpass filters and RF diplexers: single-band and dual-band." International Journal of Microwave and Wireless Technologies 14, no. 3 (November 5, 2021): 293–304. http://dx.doi.org/10.1017/s1759078721001471.
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AbstractThe manuscript reports on additively-manufactured (AM) coaxial-resonator-based bandpass filters (BPFs) and RF diplexers. A monolithic integration concept using stereolithography apparatus (SLA) is proposed and discussed in detail. Coupled-resonator-based synthesis alongside full-electromagnetic-based design methods is used for the design of the monolithic filters and RF diplexers. In particular, the paper discusses a new external coupling mechanism for dual-band BPFs that allow to independently control the coupling in each of the BPF passbands. Furthermore, a novel coaxial transmission line-type T-junction is proposed for the design of single- and dual-band RF diplexers. For practical validation purposes, multiple BPF and RF diplexer prototypes were designed, manufactured and tested at S- and C-band demonstrating the applicability of the proposed concept to low-cost, low-loss and low-weight RF components with complex geometrical features.
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Zhilyakov, Evgeny G., Sergei P. Belov, Ivan I. Oleinik, Sergei L. Babarinov, and Diana I. Trubitsyna. "Generalized sub band analysis and signal synthesis." Bulletin of Electrical Engineering and Informatics 9, no. 3 (June 1, 2020): 964–72. http://dx.doi.org/10.11591/eei.v9i3.1709.
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Currently, one of the main approaches used in analyzing properties and synthesis of signals in various classes is the subband methodology, which is carried out from the position of Fourier transform of signal samples (frequency representations) into subbands of the transform definition domain (transformants). In this case, the main tool, which is widely used for subband analysis (including wavelet analysis), is usage of bandpass filters (mainly those with finite impulse response or FIR filters). The present paper introduces the basics of building a theory forsubband analysis / signal synthesis for various classes, and using transformations based on any orthonormal basis with weight. This proposed approach is based on the concept of Euclidean signal norm square fraction in a given subband of the transformant definition domain. It is shown that the basis for mathematical apparatus of subband analysis is a new class of matrices, called subband ones. Some eigenvalue properties of these matrices are established, and the problem of optimal selection for additive signal components is formulated and solved
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Zhang, Qian, Kuo-Jui Wu, and Ming-Lang Tseng. "Exploring Carry Trade and Exchange Rate toward Sustainable Financial Resources: An application of the Artificial Intelligence UKF Method." Sustainability 11, no. 12 (June 12, 2019): 3240. http://dx.doi.org/10.3390/su11123240.
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This paper constructs a heterogeneous agent model for the foreign exchange market that is based on the law of supply and demand and includes carry trade, central bank intervention, and macroeconomic fundamentals. With the artificial intelligence method of the unscented Kalman filter, this paper investigates carry traders’ expectation formation and risk aversion and the impact of their activities on the movement of the Chinese yuan exchange rate and on the efficiency of central bank intervention. The findings demonstrate that carry traders’ activities are partially responsible for fluctuations in the Chinese yuan exchange rate; carry traders behave with obvious risk aversion; their activities tend to weaken the ability of the central bank to intervene in China’s foreign exchange market; and the volatility of the Chinese yuan exchange rate and the weight of carry traders are negatively related. Based on these empirical results, specific suggestions for exploring sustainable financial resources are provided.
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Tamami, Wimpi Rizal. "PENINGKATAN FAKTOR DAYA DAN EFFESIENSI KONSUMSI ENERGI LISTRIK PADA KAPAL BULK CARRIER 50.000 DWT (DEAD WEIGHT TON) MENGGUNAKAN FILTER PASIF." MEDIA ELEKTRIKA 14, no. 2 (March 14, 2022): 62. http://dx.doi.org/10.26714/me.14.2.2021.62-75.
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Sistem kelistrikkan kapal Bulk Carrier 50.000 dwt (dead weight ton) memiliki faktor daya yang menurun akibat besarnya beban-beban yang bersifat induktif, sehingga membutuhkan kapasitor bank untuk peningkatan faktor daya. Filter pasif selain untuk memperbaiki kecacatan gelombang dapat juga meningkatkan faktor daya. Pada Tugas Akhir ini dilakukan simulasi pemasangan manual step kapasitor dan filter pasif di setiap skema pembebanan. di hasil simulasi rata rata peningkatan faktor daya dari semua skema pembebanan adalah 10,15%. Pada tugas akhir ini perhitungan rata rata penghematan bahan bakar pada semua skema pembebanan dengan hasil Rp 1.338.246. dan pada skema beban penuh mendapatkan hasil penghematan Rp 2.213.640 per harinya dari Rp 35.297.496 menjadi Rp 33.083.856.
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Sotzen, Kristin S., Kevin B. Stevenson, Erin M. May, Natasha E. Batalha, Noam R. Izenberg, Sarah M. Hörst, Calley L. Tinsman, et al. "On the Utility of Transmission Color Analysis i: Differentiating Super-Earths and Sub-Neptunes." Astronomical Journal 162, no. 4 (September 28, 2021): 168. http://dx.doi.org/10.3847/1538-3881/ac0e2c.
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Abstract The majority of exoplanets found to date have been discovered via the transit method, and transmission spectroscopy represents the primary method of studying these distant worlds. Currently, in-depth atmospheric characterization of transiting exoplanets entails the use of spectrographs on large telescopes, requiring significant observing time to study each planet. Previous studies have demonstrated trends for solar system worlds using color–color photometry of reflectance spectra, as well as trends within transmission spectra for hot Jupiters. Building on these concepts, we have investigated the use of transmission color photometric analysis for efficient, coarse categorization of exoplanets and for assessing the nature of these worlds, with a focus on resolving the bulk composition degeneracy to aid in discriminating super-Earths and sub-Neptunes. We present our methodology and first results, including spectrum models, model comparison frameworks, and wave band selection criteria. We present our results for different transmission “color” metrics, filter selection methods, and numbers of filters. Assuming noise-free spectra of isothermal atmospheres in chemical equilibrium, with our pipeline, we are able to constrain atmospheric mean molecular weight in order to distinguish between super-Earth and sub-Neptune atmospheres with >90% overall accuracy using specific low-resolution filter combinations, . We also found that increasing the number of filters does not substantially impact this performance. This method could allow for broad characterization of large numbers of planets much more efficiently than current methods permit, enabling population- and system-level studies. Additionally, data collected via this method could inform follow-up observing time by large telescopes for more detailed studies of worlds of interest.
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Vieira, M., M. A. Vieira, P. Louro, A. Fantoni, V. Silva, and M. Barata. "SiC multilayer photonic structures with self optical bias amplification." MRS Proceedings 1426 (2012): 229–35. http://dx.doi.org/10.1557/opl.2012.887.
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ABSTRACTStacked layered pin a-SiC/a-Si devices based on a filter design are approached from a reconfigurable point of view. This paper shows that a double SiC/Si pin photodiode can be de-composed into two photonic active filters changeable in function. Reconfiguration is provided by optical control signals to the optoelectronic front and back pin building blocks. Depending on the wavelength and irradiation side of the external optical bias the device acts either as a short- and a long- pass band filter or as a band-stop filter, amplifying or rejecting a specific wavelength range. Particular attention is given to the amplification coefficient weights, which allow taking into account the wavelength background effects. We illustrate these effects in detail and discuss the filters transfer function characteristics. We present examples of filters and we propose a reconfigurable device for directed optical logic. An algorithm to decode the information is presented. An optoelectronic model supports the optoelectronic logic architecture.
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Atamanskyi, D. V., V. P. Riabukha, V. M. Kartashov, A. V. Semeniaka, and L. V. Procopenco. "SPECTRAL ESTIMATION METHODS FOR A JOINT SYSTEM OF THE NON-NOISE-LIKE TARGETS DETECTION AND THE NOISE RADIATING SOURCES LOCALIZATION." Radio Electronics, Computer Science, Control, no. 1 (April 1, 2022): 7. http://dx.doi.org/10.15588/1607-3274-2022-1-1.
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Context. For many radars, the autonomous systems of the non-noise-like aerial targets (AT) detection and the noise radiating sources (NRS) localization (direction-of-arrival estimation) may be replaced with a single detection-localization system, which carries out the common operations of the AT-detection and the NRS-localization only once. For such a system, groups of noneigenvalue and eigenvalue decomposition based “super-resolving” spectral estimation (SE) methods are considered to substantiate efficient one for the NRS-localization.
Objective. The comparative analysis efficiency of the SE-methods of different groups by a set of criteria and recommendations on their practical application.
Method. The methods’ efficiency is analyzed analytically, under simulation results and their comparison with new results presented in the open literature. In the simulation, a well-grounded and practically examined software-algorithmic basis of adaptive lattice filters for nonparametric SE-methods implementation is used.
The results. It is shown that the SE-methods of both groups have no restrictions on the antenna array configuration (flat, ring, etc.), including when used in non-equal spaced “sparse” antenna arrays with inter-element distances of more than half radar wavelength. A comparison is made on the resolution (determination of the NRS number) and the NRS-localization (direction-of-arrival estimation) efficiency by methods of different groups when using various antenna arrays. It is shown that the methods of the first group (non-eigenvalue based) in terms of the probability of correct resolution, are almost not inferior to the known and new methods of the second group (eigenvalue ones). Based on the set of criteria and practical application conditions for direction-of-arrival estimation of the noise radiating sources, it is recommended to use the Capon’s minimum variance method if there are limitations on the computational complexity of the method. In the absence of such restrictions, it is advisable to use the SE-bank of methods.
Conclusions. For the practical implementation of a joint system of the non-noise-like aerial target detection and the noise radiating sources localization, a structural-algorithmic basis of adaptive lattice filters is preferred. Using latter, along with the weight vector forming for the target detection, it is possible to implement not only the Capon’s method, but also a SE-bank of methods by combining the squares of absolute values of its original vectors’ components.
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SAHU, O. P., M. K. SONI, and I. M. TALWAR. "DESIGNING QUADRATURE MIRROR FILTER BANKS USING STEEPEST DESCENT METHOD." Journal of Circuits, Systems and Computers 15, no. 01 (February 2006): 29–41. http://dx.doi.org/10.1142/s0218126606002903.
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This paper proposes a new technique for the design of quadrature mirror filter (QMF) banks by exploiting steepest descent method. The design problem is formulated to minimize an objective function, which is a weighted sum of the pass band error and stop band residual energy of the low pass analysis filter of the QMF bank. The minimization has been carried out gradually by respective optimum step lengths in the corresponding steepest descent directions of a linear combination of the objective function and square of the reconstruction error of the QMF bank at the quadrature frequency by optimizing the filter tap weights. The design results show that the proposed method gives a comparable performance to the already existing methods.
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Abdullah-Al-Mamun, K., F. Sarker, and G. Muhammad. "A High Resolution Pitch Detection Algorithm Based on AMDF and ACF." Journal of Scientific Research 1, no. 3 (August 29, 2009): 508–15. http://dx.doi.org/10.3329/jsr.v1i3.2569.
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This paper proposes a noise robust high resolution pitch detection algorithm based on AMDF and ACF. The falling trend of AMDF is eliminated by an alignment technique, and AMDF and ACF are combined to take the advantage of their complementary nature. These two functions are combined by multiplication and addition over several band pass filters to enhance important candidates and suppress less important candidates. Then using a sophisticated weight assignment procedure, the candidate with the highest weight is selected as pitch. The proposed method is evaluated on different colored noisy speech at different intensity. Experimental result shows noise robustness of the proposed method in varied environments. Keywords: AMDF; ACM; Pitch; Voice activity detection (VAD). © 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i3.2569 J. Sci. Res. 1 (3), 508-515 (2009)
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Xu, Xiao Wen. "A New Local and Global Model to Iris Recognition." Advanced Materials Research 658 (January 2013): 592–96. http://dx.doi.org/10.4028/www.scientific.net/amr.658.592.
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Traditional iris recognition systems transfer iris images to polar coordinates, normalize the images and achieve rotation invariance by rotating the feature vector. In order to decrease the complexity of the typical iris recognition method, we propose a new method of iris recognition based on global and local model that are extracted from preprocessed iris image without normalizing. Firstly, we applied a bank of no-tensor product wavelet filters to extract the global features of the iris. Secondly, we used a SIFT method to extract the local features points of the selected regions. Finally, we tested the similarity distances of local and global features with different weights. Experimental results show that the proposed method in this paper has the recognition accuracy of 99.5% when the equal error rate is 0.94%. Without normalizing the iris images, the proposed approach can obtain very good recognition performance.
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Bianchi, Maria, Patrizia Papacci, Serena Spartano, Alessandra Landini, Carmen Giannantonio, Maria Fioretti, Costantino Romagnoli, Gina Zini, and Luciana Teofili. "Transfusion Of Very Low Birth Weight Neonates Using Allogeneic Cord Blood Derived RBC Units." Blood 122, no. 21 (November 15, 2013): 2398. http://dx.doi.org/10.1182/blood.v122.21.2398.2398.
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Abstract Infants with very low birth weight (VLBW) frequently need transfusions of red blood cells (RBCs) during the first weeks of life. However, adult blood transfusions are acknowledged risk factors for several complications, including Retinopathy of Prematurity (ROP), cytomegalovirus infection and necrotizing enterocolitis. For ROP, for example, it is thought that adult hemoglobin (HbA), with lower affinity for oxygen than foetal HbF, may induce an oxidative damage (Romagnoli C. Early Hum Dev 2009; 85, 10 Suppl:S79-S82). Previous studies showed that autologous cord blood (CB) could serve as source of RBCs for transfuse neonates; nevertheless, his clinical use is still limited, expecially because of the small volumes achieved after processing of the UCB unit. In a previous study we demonstrated that CB derived buffy coat–depleted RBC units obtained through automated separation (Compomat G4®, Fresenius HemoCare, Germany) and stored in SAG-Mannitol solution represent a suitable product for homologous transfusion of neonates. Actually, CB RBC units show hemoglobin content and hematocrit (Htc) values similar to adult RBC units stored for comparable periods, whereas the lactate concentrations are lower and the pH values are higher (Bianchi et al. ASH Annual Meeting Abstracts 2012, 120:275). We are now assessing the feasibility of covering the transfusion needs of VLBW neonates using allogeneic CB packed RBC units collected at our Cord Blood Bank. This practice has never been used before and we show here for the first time our experience on allogeneic CB derived RBC transfusion. VLBW neonates admitted to the Neonatal Intensive Care Unit needing RBC transfusions in the first 28 days of life receive adult (A group) or CB (CB group) RBC units, on the basis of the availability of an AB0-Rh compatible CB RBC unit. The arm assignment drives the choice of the RBC products (adult versus CB) in case of subsequent transfusions. All patients receive a fixed dose of 20 ml/kg RBC. Htc values are acquired before and after transfusion (ΔHtc). CB RBC units are processed and stored as previously reported (Bianchi et al. ASH Annual Meeting Abstracts 2012, 120:275). After matching tests, CB and adult units are irradiated and filtered; the Purecell RN Neonatal filters (PALL Medical, UK) are used for CB units. So far, 9 patients entered the study. Five patients are in the A group and 4 in the CB group, with similar gestational age (mean 27 + 1 weeks in group A and 27 + 3 weeks in group CB, respectively), gender (male/female ratio 3/1 in A group and 4/1 in CB group, respectively) birth weight (mean weight 915 + 225 gr in A group and 918 + 389 gr in B group, respectively) and Htc values at birth (57.2 + 8.4% in A group and 55.5 + 5.2% in CB group, respectively). On the whole, 21 RBC units were transfused, 7 in the A group and 14 in the CB group. The mean storage time was 5 + 4 days for adult RBC units and 9 + 3 days for CB units. The Htc values of patients at the time of transfusion were similar in the two groups (32,2 + 4% in A group and 30.64 + 4% in CB group, respectively, p=0.287). The ΔHtc was similar in A and CB groups, with a mean increase of 15.1 + 5 % in A group and 13.3 + 5% in the CB group, respectively, p = 0,426). No transfusion related adverse event occurred in both arms. CB can be safely administrated to preterm infants: as compared to adult, cord blood is functionally more appropriate and is safer for infectious and immunological complications. Given the wide availability of discharged units at public cord blood banks, CB derived RBC transfusion can constitute a valid therapeutic option for VLBW neonates. The study was supported by a grant from Genitin (Associazione dei Genitori per la Terapia Intensiva Neonatale). Disclosures: No relevant conflicts of interest to declare.
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Falkovich, A. H., E. R. Graber, G. Schkolnik, Y. Rudich, W. Maenhaut, and P. Artaxo. "Low molecular weight organic acids in aerosol particles from Rondônia, Brazil, during the biomass-burning, transition and wet periods." Atmospheric Chemistry and Physics 5, no. 3 (March 10, 2005): 781–97. http://dx.doi.org/10.5194/acp-5-781-2005.
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Abstract. Particles from biomass burning and regional haze were sampled in Rondônia, Brazil, during dry, transition and wet periods from September to November 2002, as part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall, and Climate) field campaign. Water soluble organic and inorganic compounds in bulk (High Volume and Stacked Filter Unit sampler) and size-resolved (Micro Orifice Uniform Deposit Impactor – MOUDI) smoke samples were determined by ion chromatography. It was found that low molecular weight polar organic acids account for a significant fraction of the water soluble organic carbon (WSOC) in biomass burning aerosols (C2-C6 dicarboxylic acids reached up to 3.7% and one-ring aromatic acids reached up to 2% of fine fraction WSOC during burning period). Short dicarboxylic (C2-C6) acids are dominated by oxalic acid followed by malonic and succinic acids. The largest ionic species is ammonium sulfate (60–70% of ionic mass). It was found that most of the ionic mass is concentrated in submicrometer-sized particles. Based on the size distribution and correlations with K+, a known biomass burning tracer, it is suggested that many of the organic acids are directly emitted by vegetation fires. Concentrations of dicarboxylic acids in the front and back filters of high volume sampler were determined. Based on these measurements, it was concluded that in the neutral or slightly basic smoke particles typical of this region, dicarboxylic acids are mostly confined to the particulate phase. Finally, it is shown that the distribution of water soluble species shifts to larger aerosols sizes as the aerosol population ages and mixes with other aerosol types in the atmosphere.
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Takakura, Tadashi, Masako Akutsu, Haruki Sunagawa, Takae Usui, Maro Tamaki, Naoki Taniai, Masaki Hirata, and Akira Kaiho. "NON-DESTRUCTIVE, REAL-TIME, AND AUTOMATIC MEASUREMENT OF TRANSPIRATION FROM A PLANT CANOPY STAND." JOURNAL OF ADVANCES IN AGRICULTURE 5, no. 2 (December 15, 2016): 677–83. http://dx.doi.org/10.24297/jaa.v5i2.5083.
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This study to measure plant canopy stand transpiration was conducted using newly developed sensor units. Transpiration from the tomato stand and by artificial leaves made of towel and paper filters showed good agreement with data measured by weight loss using a weighing device. The problem of sun flecks directly on the back side of the sensor causes malfunction of the energy balance equation, which is the basis of this method when LAI is not dense. During the period when a sun fleck was on the sensor, the data were eliminated. Overall measurements of this kind are far superior to measurements taken using a leaf porometer to estimate transpiration from the entire plant canopy stand.
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Oliveira, Cláuber Muniz de, Alexandre Henrique de Sousa Lima, and Marcela Álvares Oliveira. "Characterization of solid waste in the permanent preservation area of the Bate Estacas stream, Porto Velho, Rondônia." Nature and Conservation 14, no. 2 (April 1, 2021): 22–32. http://dx.doi.org/10.6008/cbpc2318-2881.2021.002.0003.
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Permanent Preservation Areas serve as filters to prevent impurities from reaching water bodies, protecting the banks from erosion, avoiding the obstruction of rivers caused by waste dumped in inappropriate places. The present study aimed to inventory, quantify, and analyze the types of solid waste irregularly deposited on the banks and in the Bate Estacas stream in Porto Velho, Rondônia. The Bate Estaca stream is approximately 6.5 km² long, covering the Cohab, Castanheira, Caladinho, and Aeroclube neighborhoods. The data collection was conducted in plots located in isolated tree stretches, approximately 100 meters long, in the stream's Permanent Preservation Areas. The plots' dimensions were 10x10 meters, separated by a distance of 10 meters, totaling three plots. This study presented data on the composition and average weight of solid waste in Permanent Preservation Areas, associated with urban streams in Porto Velho's municipality. We recorded almost 3 tons of waste in 300m², with plastic being the dominant item in quantity and construction material in weight. The irregular disposal is a result of the lack of inspection, basic sanitation, and knowledge of the residents living near the stream about the importance of these areas.
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Lorato, Ilde, Sander Stuijk, Mohammed Meftah, Deedee Kommers, Peter Andriessen, Carola van Pul, and Gerard de Haan. "Automatic Separation of Respiratory Flow from Motion in Thermal Videos for Infant Apnea Detection." Sensors 21, no. 18 (September 21, 2021): 6306. http://dx.doi.org/10.3390/s21186306.
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Both Respiratory Flow (RF) and Respiratory Motion (RM) are visible in thermal recordings of infants. Monitoring these two signals usually requires landmark detection for the selection of a region of interest. Other approaches combine respiratory signals coming from both RF and RM, obtaining a Mixed Respiratory (MR) signal. The detection and classification of apneas, particularly common in preterm infants with low birth weight, would benefit from monitoring both RF and RM, or MR, signals. Therefore, we propose in this work an automatic RF pixel detector not based on facial/body landmarks. The method is based on the property of RF pixels in thermal videos, which are in areas with a smooth circular gradient. We defined 5 features combined with the use of a bank of Gabor filters that together allow selection of the RF pixels. The algorithm was tested on thermal recordings of 9 infants amounting to a total of 132 min acquired in a neonatal ward. On average the percentage of correctly identified RF pixels was 84%. Obstructive Apneas (OAs) were simulated as a proof of concept to prove the advantage in monitoring the RF signal compared to the MR signal. The sensitivity in the simulated OA detection improved for the RF signal reaching 73% against the 23% of the MR signal. Overall, the method yielded promising results, although the positioning and number of cameras used could be further optimized for optimal RF visibility.
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Li, Mingai, Ruotu Wang, and Dongqin Xu. "An Improved Composite Multiscale Fuzzy Entropy for Feature Extraction of MI-EEG." Entropy 22, no. 12 (November 30, 2020): 1356. http://dx.doi.org/10.3390/e22121356.
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Motor Imagery Electroencephalography (MI-EEG) has shown good prospects in neurorehabilitation, and the entropy-based nonlinear dynamic methods have been successfully applied to feature extraction of MI-EEG. Especially based on Multiscale Fuzzy Entropy (MFE), the fuzzy entropies of the τ coarse-grained sequences in τ scale are calculated and averaged to develop the Composite MFE (CMFE) with more feature information. However, the coarse-grained process fails to match the nonstationary characteristic of MI-EEG by a mean filtering algorithm. In this paper, CMFE is improved by assigning the different weight factors to the different sample points in the coarse-grained process, i.e., using the weighted mean filters instead of the original mean filters, which is conductive to signal filtering and feature extraction, and the resulting personalized Weighted CMFE (WCMFE) is more suitable to represent the nonstationary MI-EEG for different subjects. All the WCMFEs of multi-channel MI-EEG are fused in serial to construct the feature vector, which is evaluated by a back-propagation neural network. Based on a public dataset, extensive experiments are conducted, yielding a relatively higher classification accuracy by WCMFE, and the statistical significance is examined by two-sample t-test. The results suggest that WCMFE is superior to the other entropy-based and traditional feature extraction methods.
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Cho, Junghyun, Yejune Seo, Jihaeng Cho, Kyoung Youl Park, Joongki Park, Hosub Lee, and Sungtek Kahng. "Effective Size Reduction of the Metallic Waveguide Bandpass Filter with Metamaterial Resonators and Its 3D-Printed Version." Sensors 23, no. 3 (January 19, 2023): 1173. http://dx.doi.org/10.3390/s23031173.
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In this paper, a novel method is proposed to effectively reduce the size of a waveguide bandpass filter (BPF). Because the metallic cavities make the conventional waveguide end up with a large geometry, especially for high-order BPFs, very compact waveguide-type resonators having metamaterial zeroth-order resonance (WG ZOR) are designed on the cross section of the waveguide and substituted for the cavities. While the cavities are half-wavelength resonators, the WG ZOR is shorter than one-eighth of a wavelength. A substantial reduction in the size and weight of the waveguide filter is observed as the resonators are cascaded in series through coupling elements in the X-band that is much longer than that in K- or Ka-bands. The proposed metamaterial filter is realized as a 3D-printed structure to be lighter and thus more suitable for low earth orbit (LEO) satellites. An X-band of 7.25–7.75 GHz is chosen to verify the method as the passband with an attenuation of 40 dB at 7.00 GHz and 8.00 GHz as the roll-off in the stopband. The BPF is manufactured in two ways, namely the CNC-milling technique and metal coating–added 3D printing. The design is carried out with a geometrical parameter of not 10−2 mm but rather 10-1 mm, which is good for manufacturers but challenging for component designers. The measurement of the manufactured metal waveguide filters reveals that the passband has about ≤1 dB and ≤−15 dB as the insertion loss and the reflection coefficient, respectively, and the stopband has an attenuation of ≤−40 dB, which are in good agreement with the results of the circuit and the simulation. The proposed filter has a length of 14 cm as the eighth-order BPF, but the conventional waveguide is 20 cm as the seventh-order BPF for the same area of the cross section.
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Paramanik, Rajendra, and Bandi Kamaiah. "An empirical analysis of Indian business cycle dynamics." Ekonomski anali 62, no. 213 (2017): 7–25. http://dx.doi.org/10.2298/eka1713007p.
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This paper attempts to construct a monthly Composite Index of Leading Indicators (CILI) for the Indian business cycle between April 1994 and December 2015. The cyclical component of the Index of Industrial Production (IIP), generated by Baxter-King band pass filters, is considered as a reference series for Indian business cycle analysis. A set of indicator variables pertaining to different sectors of the economy are chosen on the basis of their strong leading correlation with the reference series. Further, Principal Component Analysis (PCA) technique is applied to assign an appropriate weight to each leading variable, and a CILI is constructed. The performance of the CILI is validated using the turning-point analysis of BryBoschan and Harding-Pagan. The CILI accurately predicts two major troughs in the Indian business cycle, with six and eleven month leads respectively.
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Rajapakse, Nihal C., Robert K. Pollock, Margaret J. McMahon, John W. Kelly, and Roy E. Young. "Interpretation of Light Quality Measurements and Plant Response in Spectral Filter Research." HortScience 27, no. 11 (November 1992): 1208–11. http://dx.doi.org/10.21273/hortsci.27.11.1208.
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Experiments were conducted to correlate the response of chrysanthemum [Dendrathema ×grandiflorum (Ramat.) Kitamura] plants to light environment based on various quantitative light quality parameters by growing plants under 6% or 40% CuSO4 and water spectral filters. Using a narrow band width (R = 655-665 and FR = 725-735 nm) or a broad band width (R = 600-700 and FR = 700-800 nm) for R: FR ratio calculation, 6% CuSO4 filter transmitted light with a higher R: FR ratio than 40% CuSO4 or water filters. Light transmitted through 40% CuSO4 and water filters had similar narrow band R: FR ratios (≈1.2), but the broad band R: FR ratio (2.0) of 40% CuSO4 filter was higher than that of water filters. The estimated phytochrome photoequilibrium (ϕ) value varied considerably with the photochemical properties of phytochrome used for estimations. Final height and internode length of plants grown in 6% or 40% CuSO4 chambers was ≈30% less than of plants in corresponding control chambers. Leaf and stem dry weights were reduced by light transmitted through CuSO4 filters. The results suggest that broad band R: FR ratio correlated more closely to above plant responses than the narrow band R: FR ratio. Blue (B): R and B: FR ratios (not absolute amount of blue wavelengths) correlated well with plant response, suggesting that involvement of blue light should not be ignored in expressing plant response to light transmitted through CuSO4 filters. At present, the presentation of complete spectral data would be the most useful in explaining plant response to light environment.
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Spector, Steven, and Cheryl Sorace-Agaskar. "Silicon photonics devices for integrated analog signal processing and sampling." Nanophotonics 3, no. 4-5 (August 1, 2014): 313–27. http://dx.doi.org/10.1515/nanoph-2013-0036.
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AbstractSilicon photonics offers the possibility of a reduction in size weight and power for many optical systems, and could open up the ability to build optical systems with complexities that would otherwise be impossible to achieve. Silicon photonics is an emerging technology that has already been inserted into commercial communication products. This technology has also been applied to analog signal processing applications. MIT Lincoln Laboratory in collaboration with groups at MIT has developed a toolkit of silicon photonic devices with a focus on the needs of analog systems. This toolkit includes low-loss waveguides, a high-speed modulator, ring resonator based filter bank, and all-silicon photodiodes. The components are integrated together for a hybrid photonic and electronic analog-to-digital converter. The development and performance of these devices will be discussed. Additionally, the linear performance of these devices, which is important for analog systems, is also investigated.
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Zhao, He-Wei, and Li-bin Yang. "Global adaptive neural backstepping control of a flexible hypersonic vehicle with disturbance estimation." Aircraft Engineering and Aerospace Technology 94, no. 4 (October 5, 2021): 492–504. http://dx.doi.org/10.1108/aeat-08-2020-0178.
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Purpose This paper aims to discuss the precise altitude and velocity tracking control of a hypersonic vehicle, a global adaptive neural backstepping controller was studied based on a disturbance observer (DOB). Design/methodology/approach The DOB combined with a radial basis function (RBF) neural network (NN) was used to estimate the disturbance terms that are generated by the flexible modes of the hypersonic vehicle system. A global adaptive neural method was introduced to approximate the unknown system dynamics, with robust control terms pulling the system transient states back into the neural approximation domain externally. Findings The globally uniformly ultimately bounded for all signals of a closed-loop system can be guaranteed by the proposed control algorithm. Additionally, the command filtered backstepping methods can avoid the explosion of the complexity problem caused by the backstepping design process. In addition, the effectiveness of the proposed controller can be verified by the simulation used in this study. Research limitations/implications Normally lateral dynamics issue should be discussed in the process of control system designed, the lateral dynamics are not included in the nonlinear dynamic model of hypersonic vehicle used in this paper, merely the longitudinal flight dynamics are discussed in this paper. Originality/value The flexible states in rigid modes are considered as the disturbance of the system, which is estimated by structuring DOB with NN approximations. The compensating tracking error and prediction error are used in the update law of RBF NN weight. The differential explosions complexity derived from the backstepping procedure is dealt with by using command filters.
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Zhao, He-Wei, and Li-bin Yang. "Global adaptive neural backstepping control of a flexible hypersonic vehicle with disturbance estimation." Aircraft Engineering and Aerospace Technology 94, no. 4 (October 5, 2021): 492–504. http://dx.doi.org/10.1108/aeat-08-2020-0178.
Full textAbstract:
Purpose This paper aims to discuss the precise altitude and velocity tracking control of a hypersonic vehicle, a global adaptive neural backstepping controller was studied based on a disturbance observer (DOB). Design/methodology/approach The DOB combined with a radial basis function (RBF) neural network (NN) was used to estimate the disturbance terms that are generated by the flexible modes of the hypersonic vehicle system. A global adaptive neural method was introduced to approximate the unknown system dynamics, with robust control terms pulling the system transient states back into the neural approximation domain externally. Findings The globally uniformly ultimately bounded for all signals of a closed-loop system can be guaranteed by the proposed control algorithm. Additionally, the command filtered backstepping methods can avoid the explosion of the complexity problem caused by the backstepping design process. In addition, the effectiveness of the proposed controller can be verified by the simulation used in this study. Research limitations/implications Normally lateral dynamics issue should be discussed in the process of control system designed, the lateral dynamics are not included in the nonlinear dynamic model of hypersonic vehicle used in this paper, merely the longitudinal flight dynamics are discussed in this paper. Originality/value The flexible states in rigid modes are considered as the disturbance of the system, which is estimated by structuring DOB with NN approximations. The compensating tracking error and prediction error are used in the update law of RBF NN weight. The differential explosions complexity derived from the backstepping procedure is dealt with by using command filters.
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Jia, Weibin, Zhihuan Song, and Zhengguo Li. "Multi-scale Fusion of Stretched Infrared and Visible Images." Sensors 22, no. 17 (September 2, 2022): 6660. http://dx.doi.org/10.3390/s22176660.
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Infrared (IR) band sensors can capture digital images under challenging conditions, such as haze, smoke, and fog, while visible (VIS) band sensors seize abundant texture information. It is desired to fuse IR and VIS images to generate a more informative image. In this paper, a novel multi-scale IR and VIS images fusion algorithm is proposed to integrate information from both the images into the fused image and preserve the color of the VIS image. A content-adaptive gamma correction is first introduced to stretch the IR images by using one of the simplest edge-preserving filters, which alleviates excessive luminance shifts and color distortions in the fused images. New contrast and exposedness measures are then introduced for the stretched IR and VIS images to achieve weight matrices that are more in line with their characteristics. The IR and luminance components of the VIS image in grayscale or RGB space are fused by using the Gaussian and Laplacian pyramids. The RGB components of the VIS image are finally expanded to generate the fused image if necessary. Comparisons experimentally demonstrate the effectiveness of the proposed algorithm to 10 different state-of-the-art fusion algorithms in terms of computational cost and quality of the fused images.
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Molchanova, E. I., E. N. Korzhova, V. V. Fedorov, and A. D. Portnyagin. "Assessment of the possibility of modeling nonlinear multivariable calibration function using artificial neural networks." Industrial laboratory. Diagnostics of materials 87, no. 10 (October 18, 2021): 12–17. http://dx.doi.org/10.26896/1028-6861-2021-87-10-12-17.
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The use of artificial neural networks (ANNs) is considered justified when studying the problems that do not have a generally accepted solution algorithm. One of such problems in X-ray fluorescence analysis (XRF) is a control of the metal content in atmospheric air and air of the working area. Determination of the calibration characteristics is raveled by the lack of standard samples of the composition of aerosols collected on the filter. To solve this problem, synthetic calibration samples (CS) were manufactured as a thin organic film containing a powder material of the known chemical composition. The weight of the film samples varied within a range of 40 – 155 mg to simulate different aerosol loading of the filters and the content of components in them changed 20 – 200 times which corresponds to the samples of real aerosols. The possibility of modeling a nonlinear calibration multivariable function using artificial neural networks was evaluated in analysis of 38 film calibration samples (from 40 to 100 mg). The structure of the neural network, activation functions, learning algorithms have been investigated. Modeling was performed using an academic version of the BaseGroup Deductor analytical platform. It is shown that implementation of the back propagation of errors leads to much higher values of the error of analysis compared to the error of the regression calibration functions, whereas the Resilient Propagation algorithm provides the smallest values of the error of vanadium determination (Sr) in the calibration samples of aerosols. The range of low content of the elements in the training set is determined with a greater error compared to high content range, and therefore, the sigmoid activation function leads to unsatisfactory accuracy of the analysis results, and preference should be given to hyperbolic tangent (tanh).
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Othman, Nurzati Iwani, Ahmad Fadzil Ismail, Khairayu Badron, Wahidah Hashim, Mohammad Kamrul Hasan, and Sofia Pinardi. "An Enhanced Dynamic Spectrum Allocation Method on Throughput Maximization in Urban 5G FBMC Heterogeneous Network." Journal of Engineering and Technological Sciences 55, no. 1 (March 31, 2023): 40–51. http://dx.doi.org/10.5614/j.eng.technol.sci.2023.55.1.5.
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Reports have shown that the demand for data managed by wireless systems is expected to grow by more than 500 exabytes by 2025 and beyond. 5G networks are predicted to meet these demands, provided that the spectrum resources are well managed. In this paper, an enhanced dynamic spectrum allocation (E-DSA) method is proposed, which incorporates a cooperative type of game theory called the Nash bargaining solution (NBS). It was assumed that there is one primary user (PU) and two secondary users (SU) in the network and their spectrum allocation was analyzed by testing the validity of the algorithm itself by using price weight factors to control the costs of the spectrum sharing. The solution was established by combining a proposed multiplexing method called the Filter Bank Multicarrier (FBMC) for 5G configuration, with the E-DSA algorithm to maximize the throughput of a heterogeneous 5G network. It was shown that the throughputs for 5G with E-DSA implementation were always higher than those of the ones without E-DSA. The simulation was done using the LabVIEW communication software and was analyzed based on a 5G urban macro and micro network configuration to validate the heterogeneity of the network.
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Pachner, Daniel, and Štepan Kroupa. "Reduced Bank of Kalman Filters." IFAC Proceedings Volumes 41, no. 2 (2008): 7245–50. http://dx.doi.org/10.3182/20080706-5-kr-1001.01226.
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Iniyavan, R., and B. Vijayalakshmi. "Design and Development of Improved Coyote Optimization-based Adaptive Equalization Technique for ECG Signal Transmission." ECTI Transactions on Electrical Engineering, Electronics, and Communications 21, no. 1 (February 28, 2023): 248608. http://dx.doi.org/10.37936/ecti-eec.2023211.248608.
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Biological signals such as an electrocardiogram (ECG) are broadcast directly through wireless devices and mobile networks during patients' real-time activities and over limitless distances. However, the transmission of signals through a limited band channel or over multi-propagation suffers from limitations such as inter-symbol interference (ISI). In channel output, the adjacent symbols smudge and integrate with each other by degenerating during error analysis. Equalization filters are used to improve such kinds of deformation. A new adaptive equalization approach is proposed in this paper to extract real broadcasted signals from Gaussian noise-distorted ECG signals using the enhanced meta-heuristic algorithm. The weight optimization strategy of the "adaptive equalization technique" is implemented using oppositional searched coyote optimization algorithm (OS-COA). The main purpose of adapting the improved meta-heuristic-based adaptive equalization technique is to decrease error in the section of receivers, thus ensuring the received ECG signal is error-free. The obtained outcomes are examined to evaluate the performance of error metrics like "mean square error (MSE), and convergence rate" of the introduced model and for comparison with other existing equalization approaches. According to the experimental evaluation, the recommended adaptive linear equalization technique has better extraction performance than other blind and nonlinear equalization approaches.
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Huang, Long Yang, Jun Luo, and Wei Jun Pan. "Spatial-Temporal Non-Uniform Subband Broadband Beamforming." Advanced Materials Research 108-111 (May 2010): 1223–28. http://dx.doi.org/10.4028/www.scientific.net/amr.108-111.1223.
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A spatial-temporal scheme based on non-uniform subband general parameter filter banks for broadband beamforming of scaled aperture array is proposed in this paper. The scaled aperture array is composed of several uniformly-spaced linear subarrays, each of which processes an octave subband signal respectively. The non-uniform subband signal is implemented by tree-structure general parameter filter banks. Each subarray broadband beamforming is carried out by a kind of tapped-delay-line (TDL) infinite-impulse-response (IIR) filters beamformer, and four subarrays share the same weights. This processing architecture based beamformer splits the broadband signal into several narrower subband ones which are processed in parallel, and subarray is operating with lower sampling rate, which contributes to decreasing the computational load significantly and improving the speed and performances as well. Simulations show that computation complexity and load of this beamformer are much lower relative to the conventional TDL broadband beamfomer.
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Mishra, Annapurna, and Satchidananda Dehuri. "Real-time online fingerprint image classification using adaptive hybrid techniques." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 5 (October 1, 2019): 4372. http://dx.doi.org/10.11591/ijece.v9i5.pp4372-4381.
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<p class="Abstract">This paper presents three different hybrid classification techniques applied for the first time in real-time online fingerprint classification. Classification of online real time fingerprints is a complex task as it involves adaptation and tuning of classifier parameters for better classification accuracy. To accomplish the optimal adaptation of parameters of functional link artificial neural network (FLANN) for real-time online fingerprint classification, proven and established optimizers, such as Biogeography based optimizer (BBO), Genetic algorithm (GA), and Particle swarm optimizer (PSO) are intelligently infused with it to form hybrid classifiers. The global features of the real-time fingerprints are extracted using a Gabor filter-bank and then passed into adaptive hybrid classifiers for the desired classification as per the Henry system. Three hybrid classifiers, the optimized weight adapted Biogeography based optimized functional link artificial neural network (BBO-FLANN), Genetic algorithm based functional link artificial neural network (GA-FLANN) and Particle swarm optimized functional link artificial neural network (PSO-FLANN), are explored for real-time online fingerprint classification, where the PSO-FLANN technique is showing superior performance as compared to GA-FLANN and BBO-FLANN techniques. The best accuracy observed by the application of PSO-FLANN, is 98% for real-time online fingerprint classification.</p>
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Apellániz, J. Maíz. "The range of validity of cluster masses and ages derived from broad-band photometry." Proceedings of the International Astronomical Union 5, S266 (August 2009): 100–105. http://dx.doi.org/10.1017/s1743921309990937.
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AbstractI analyze the stochastic effects introduced by sampling the stellar initial mass function (SIMF) in the derivation of the individual masses and the cluster mass function (CMF) from broad-band visible/near-infrared unresolved photometry. The classical method of using unweighted U BV photometry to simultaneously establish ages and extinctions of stellar clusters is found to be unreliable for clusters older than ≈30 Myr, even for relatively large cluster masses. On the other hand, augmenting the filter set to include longer-wavelength filters and using weights for each filter increases the range of masses and ages that can be measured accurately with unresolved photometry. Nevertheless, a relatively large range of masses and ages is found to be dominated by SIMF sampling effects that render the observed masses useless, even when using U BV RI JHK photometry.
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Parameshappa, G., and D. Jayadevapp. "Efficient uniform digital filter bank with linear phase and FRM technique for hearing aids." International Journal of Engineering & Technology 7, no. 1.9 (March 1, 2018): 69. http://dx.doi.org/10.14419/ijet.v7i1.9.9738.
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This paper attempts to present an uniform digital filter bank based on linear phase FIR and IIR filters applied for Frequency Response Masking (FRM) technique in hearing aid applications.In the proposed filter bank, nine uniformly spaced sub-bands are formed with the help of half band filters and masking filters. These nine channel FIR filter bank is realized using an interpolated half band linear phase FIR filter and an appropriate number of masking FIR filters. The nine channel IIR filter bank is realized using an interpolated half band approximately linear phase IIR filter and an appropriate number of masking filters. The proposed approximately linear phase IIR half band filter bank is compared with filter bank based on linear phase FIR half band filters in terms of area, power, memory and number of gates needed for implementation. The experiment was carried on various hearing loss cases and the results obtained from these tests proves that, the proposed filter bank achieved the required matching between audiograms and magnitude response of the filter bank at very reasonable range with less computational complexity.
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Barrera-Vargas, Christian A., Javier Naranjo-Pérez, Iván M. Díaz, and Jaime H. García-Palacios. "Design of a Semiactive TMD for Lightweight Pedestrian Structures Considering Human–Structure–Actuator Interaction." Actuators 11, no. 4 (March 28, 2022): 101. http://dx.doi.org/10.3390/act11040101.
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Lightweight pedestrian structures constructed with high strength-to-weight ratio materials, such as fiber-reinforced polymers (FRP), may experience large accelerations due to their lightness, thus overcoming the serviceability limit state. Additionally, uncertainties associated with human–structure interaction phenomena become relevant. Under these circumstances, variations in pedestrian actions could modify the modal properties of the coupled human–structure system and classical approaches based on passive Tuned Mass Dampers (TMD) do not offer an effective solution. An alternative solution is to use a Semiactive TMD (STMD), which includes a semiactive damper that, when properly designed, may be effective for a relatively broad frequency band, offering a robust solution when significant uncertainties are present. Thus, this paper presents a design methodology for the design of STMDs applied to lightweight pedestrian structures including human–structure and actuator–structure interaction. A multiobjective optimization procedure has been proposed to simultaneously minimize structure acceleration, inertial mass, and maximum damper force. The methodology has been applied to a lightweight FRP footbridge. Realistic simulations, including system uncertainties, interaction phenomena, nonlinear damper model, noise-contaminated signals, and the practical elements (in-line digital filters) needed for the successful implementation of the control law, validate the methodology. As a conclusion, the STMD is more effective than its passive counterpart in both, canceling the response or achieving similar performance with significant lower inertial mass.
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Kuijken, K., C. Heymans, A. Dvornik, H. Hildebrandt, J. T. A. de Jong, A. H. Wright, T. Erben, et al. "The fourth data release of the Kilo-Degree Survey: ugri imaging and nine-band optical-IR photometry over 1000 square degrees." Astronomy & Astrophysics 625 (April 30, 2019): A2. http://dx.doi.org/10.1051/0004-6361/201834918.
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Context. The Kilo-Degree Survey (KiDS) is an ongoing optical wide-field imaging survey with the OmegaCAM camera at the VLT Survey Telescope, specifically designed for measuring weak gravitational lensing by galaxies and large-scale structure. When completed it will consist of 1350 square degrees imaged in four filters (ugri). Aims. Here we present the fourth public data release which more than doubles the area of sky covered by data release 3. We also include aperture-matched ZYJHKs photometry from our partner VIKING survey on the VISTA telescope in the photometry catalogue. We illustrate the data quality and describe the catalogue content. Methods. Two dedicated pipelines are used for the production of the optical data. The ASTRO-WISE information system is used for the production of co-added images in the four survey bands, while a separate reduction of the r-band images using the THELI pipeline is used to provide a source catalogue suitable for the core weak lensing science case. All data have been re-reduced for this data release using the latest versions of the pipelines. The VIKING photometry is obtained as forced photometry on the THELI sources, using a re-reduction of the VIKING data that starts from the VISTA pawprints. Modifications to the pipelines with respect to earlier releases are described in detail. The photometry is calibrated to the Gaia DR2 G band using stellar locus regression. Results. In this data release a total of 1006 square-degree survey tiles with stacked ugri images are made available, accompanied by weight maps, masks, and single-band source lists. We also provide a multi-band catalogue based on r-band detections, including homogenized photometry and photometric redshifts, for the whole dataset. Mean limiting magnitudes (5σ in a 2″ aperture) and the tile-to-tile rms scatter are 24.23 ± 0.12, 25.12 ± 0.14, 25.02 ± 0.13, 23.68 ± 0.27 in ugri, respectively, and the mean r-band seeing is 0.″70.
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Yang, Dan, Bin Xu, Lin Lin Ye, and Xu Wang. "Speech Enhancement Using Wavelet Neural Network with Sub-Band Adaptive Matched Filter." Advanced Engineering Forum 2-3 (December 2011): 127–30. http://dx.doi.org/10.4028/www.scientific.net/aef.2-3.127.
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Wavelet Neural Network (WNN) Is a Time-frequency Analysis Method, which Detects the Subtle Small Changes in the Signal Frequency Domain. Adaptive Filter Provides a Kind of Simple and Applied Method for Processing Signals in Noise. in this Paper, we Proposed a New Speech Enhancement Technique which Is Based on Wavelet Neural Network Using Adaptive Matched Filter Adjusting Weight. we Choose the Signal with Noise Pollution as the Input Signal and then Put it to the Trained Wavelet Neural Network. Wavelet Decomposition and Wavelet Neural Network Weights Processing Adopt Signal Sub-band Adaptive Matched Filter, the Output Signal of Wavelet Neural Network Is an Approximation Form of Original Signal. the Results Show that the WNN Is a Quite Effective Method for the Speech Enhancement and Improving the Ration of Signal to Noise.
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Hu, Kai, Aiguo Song, Min Xia, XiaoLing Ye, and YanYan Dou. "An Adaptive Filtering Algorithm Based on Genetic Algorithm-Backpropagation Network." Mathematical Problems in Engineering 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/573941.
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A new image filtering algorithm is proposed. GA-BPN algorithm uses genetic algorithm (GA) to decide weights in a back propagation neural network (BPN). It has better global optimal characteristics than traditional optimal algorithm. In this paper, we used GA-BPN to do image noise filter researching work. Firstly, this paper uses training samples to train GA-BPN as the noise detector. Then, we utilize the well-trained GA-BPN to recognize noise pixels in target image. And at last, an adaptive weighted average algorithm is used to recover noise pixels recognized by GA-BPN. Experiment data shows that this algorithm has better performance than other filters.