Journal articles on the topic 'Second order difference array'
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Raza, Ahsan, Wei Liu, and Qing Shen. "Thinned Coprime Array for Second-Order Difference Co-Array Generation With Reduced Mutual Coupling." IEEE Transactions on Signal Processing 67, no. 8 (April 15, 2019): 2052–65. http://dx.doi.org/10.1109/tsp.2019.2901380.
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Zhang, Lei, Shiwei Ren, Xiangnan Li, Guishan Ren, and Xiaohua Wang. "Generalized L-Shaped Nested Array Concept Based on the Fourth-Order Difference Co-Array." Sensors 18, no. 8 (August 1, 2018): 2482. http://dx.doi.org/10.3390/s18082482.
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In this paper, a generalized L-shaped nested array based on the fourth-order difference co-array is proposed for two-dimensional (2D) directions’ estimation. The new structure framework makes full use of the physical sensor locations to form a virtual uniform rectangular array (URA) as large as possible. As it utilizes the fourth-order difference instead of the traditional second-order difference result, this structure framework can acquire a much higher degree-of-freedom (DOF) than the existing 2D sparse arrays. The proposed structures have two advantages. One is that the subarrays can be chosen as any nested-class arrays, which makes the sparse array design more flexible. We can choose arbitrary subarray structures for DOF enhancement purposes. Another advantage is that the relative position of two subarrays can be set as any integral multiple of half wavelength. This means that two subarrays can be located as far as possible so that the relative influence between two physical subarrays can be ignored. The DOFs of several typical generalized L-shaped nested arrays (GLNAs) are compared in this paper. By setting the subarrays as different types and the relative position as a special value, a special GLNA is presented. Simulations show that GLNAs have obvious superiority in 2D direction-of-arrival estimation.
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Halim, Yacine, and Julius Fergy T. Rabago. "On the solutions of a second-order difference equation in terms of generalized Padovan sequences." Mathematica Slovaca 68, no. 3 (June 26, 2018): 625–38. http://dx.doi.org/10.1515/ms-2017-0130.
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AbstractThis paper deals with the solution, stability character and asymptotic behavior of the rational difference equation$$\begin{array}{} \displaystyle x_{n+1}=\frac{\alpha x_{n-1}+\beta}{ \gamma x_{n}x_{n-1}},\qquad n \in \mathbb{N}_{0}, \end{array}$$where ℕ0= ℕ ∪ {0},α,β,γ∈ ℝ+, and the initial conditionsx–1andx0are non zero real numbers such that their solutions are associated to generalized Padovan numbers. Also, we investigate the two-dimensional case of the this equation given by$$\begin{array}{} \displaystyle x_{n+1} = \frac{\alpha x_{n-1} + \beta}{\gamma y_n x_{n-1}}, \qquad y_{n+1} = \frac{\alpha y_{n-1} +\beta}{\gamma x_n y_{n-1}} ,\qquad n\in \mathbb{N}_0. \end{array}$$
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Vazquez, J. H., and A. N. Williams. "Second-Order Diffraction Forces on an Array of Vertical Cylinders in Bichromatic Bidirectional Waves." Journal of Offshore Mechanics and Arctic Engineering 117, no. 1 (February 1, 1995): 12–18. http://dx.doi.org/10.1115/1.2826984.
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A complete second-order solution is presented for the hydrodynamic forces due to the action of bichromatic, bidirectional waves on an array of bottom-mounted, surface-piercing cylinders of arbitrary cross section in water of uniform finite depth. Based on the constant structural cross section, the first-order problem is solved utilizing a two-dimensional Green function approach, while an assisting radiation potential approach is used to obtain the hydrodynamic loads due to the second-order potential. Results are presented which illustrate the influence of wave directionality on the second-order sum and difference frequency hydrodynamic forces on a two-cylinder array. It is found that wave directionality may have a significant influence on the second-order hydrodynamic forces on these arrays and that the assumption of unidirectional waves does not always lead to conservative estimates of the second-order loading.
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Ashyralyev, Allaberen, and Betul Hicdurmaz. "Bounded solutions of second order of accuracy difference schemes for semilinear fractional schrödinger equations." Fractional Calculus and Applied Analysis 23, no. 6 (December 16, 2020): 1723–61. http://dx.doi.org/10.1515/fca-2020-0086.
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AbstractThe present paper deals with initial value problem (IVP) for semilinear fractional Schrödinger integro-differential equation$$\begin{array}{} \displaystyle i\!\frac{du}{dt}+Au = \int\limits_{0}^{t}f\left( s,D_{s}^{\alpha }u(s)\right) ds,\, \, \, 0 \lt t \lt T,\, u\left( 0\right) = 0 \end{array} $$in a Hilbert space H with a self-adjoint positive definite (SAPD) operator A. Stable difference schemes (DSs) have significant interest in investigations of fractional partial differential equations. The main theorem concerns the existence and uniqueness of the uniformly bounded solutions (UBSs) with respect to step time of second order of accuracy DSs for this semilinear fractional Schrödinger differential problem. In practice, existence and uniqueness theorems for a UBS of the one-dimensional initial boundary value problem (BVP) with nonlocal condition and multi-dimensional problem with local condition on the boundary are proved. Numerical results and explanatory illustrations are presented to show the validation of the theoretical results.
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Thomson, Antonio, Atef Elsherbeni, and Mohammed Hadi. "A Practical Fourth Order Finite-Difference Time-Domain Algorithm for the Solution of Maxwell’s Equations." Applied Computational Electromagnetics Society 35, no. 11 (February 5, 2021): 1422–23. http://dx.doi.org/10.47037/2020.aces.j.351180.
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Implementing a practical fourth order accurate in time and second order accurate in space finite difference time domain simulation using MATLAB is the goal of this paper. The formulation presented for the fourth order approximation is simple to integrate into an existing second order accurate in time and second order accurate in space formulation and well-established code. The fourth order formulation has been verified and simulation accuracy is confirmed through the application of radiation from a single and an array of dipole antennas.
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Liu, Mingxin, Lin Zou, Haohao Ren, Xuelian Yu, Yun Zhou, and Xuegang Wang. "A Novel MIMO Array with Reduced Mutual Coupling and Increased Degrees of Freedom." Mathematical Problems in Engineering 2021 (February 15, 2021): 1–6. http://dx.doi.org/10.1155/2021/3703657.
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In this paper, we consider the problem of array design for Multiple-Input Multiple-Output (MIMO) array under the condition of fixed number of physical sensors and mutual coupling. A novel MIMO array based on the second-order super nested transmit and receive arrays is proposed by using the difference coarray. It can obtain the closed form expressions for the physical sensor locations and the degrees of freedom (DOF) from any given number physical sensors. The proposed array structure can significantly enhance DOF and effectively decrease unknown mutual coupling effect. The effectiveness and superiority of the proposed MIMO array structure are verified from the number of DOF and MUSIC spectra by numerical simulations.
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Ye, Changbo, Luo Chen, and Beizuo Zhu. "Sparse Array Design for DOA Estimation of Non-Gaussian Signals: From Global Postage-Stamp Problem Perspective." Wireless Communications and Mobile Computing 2021 (February 23, 2021): 1–11. http://dx.doi.org/10.1155/2021/6616112.
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In this paper, a sparse array design problem for non-Gaussian signal direction of arrival (DOA) estimation is investigated. Compared with conventional second-order cumulant- (SOC-) based methods, fourth-order cumulant- (FOC-) based methods achieve improved DOA estimation performance by utilizing all information from received non-Gaussian sources. Considering the virtual sensor location of vectorized FOC-based methods can be calculated from the second order difference coarray of sum coarray (2-DCSC) of physical sensors, it is important to devise a sparse array design principle to obtain extended degree of freedom (DOF). Based on the properties of unfolded coprime linear array (UCLA), we formulate the sparse array design problem as a global postage-stamp problem (GPSP) and then present an array design method from GPSP perspective. Specifically, for vectorized FOC-based methods, we divide the process of obtaining physical sensor location into two steps; the first step is to obtain the two consecutive second order sum coarrays (2-SC), which can be modeled as GPSP, and the solutions to GPSP can also be utilized to determine the physical sensor location sets without interelement spacing coefficients. The second step is to adjust the physical sensor sets by multiplying the appropriate coprime coefficients, which is determined by the structure of UCLA. In addition, the 2-DCSC can be calculated from physical sensors directly, and the properties of UCLA are given to confirm the degree of freedom (DOF) of the proposed geometry. Simulation results validate the effectiveness and superiority of the proposed array geometry.
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Rosas Almeida, David I., and Laura O. Orea Leon. "Robust-Output-Controlled Synchronization Strategy for Arrays of Pancreatic β-Cells." Complexity 2018 (November 5, 2018): 1–10. http://dx.doi.org/10.1155/2018/5174981.
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This paper presents a synchronization strategy based on second-order sliding mode control, to obtain robust controlled synchronization in an array of uncertain pancreatic β-cells. This strategy considers a synchronization scheme with a reference cell, which incorporates the desired dynamics, and an array of cells, which does not demonstrate adequate synchronization. The array may be formed by active and inactive cells having different strengths in gap junctions. For an array with three cells, we design the coupling signal considering that only the output of an active cell of the array is available. The coupling signal is the signum of the difference between the output of the reference cell and the output of an active cell in the array; this ensures exact synchronization in finite time between both cells. Then, this coupling signal is applied to the other cells in the array, and we establish the conditions required to be satisfied to obtain approximate synchronization between the reference cell and all other cells in the array. The performance of this technique is demonstrated by the results of numerical simulations performed for several cases of connections for an array with three cells and the reference cell. Finally, we show through a numerical simulation that this technique can be applied to arrays with many β-cells.
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Zhao, Meiling, Jiahui He, and Na Zhu. "Fast High-Order Algorithms for Electromagnetic Scattering Problem from Finite Array of Cavities in TE Case with High Wave Numbers." Mathematics 10, no. 16 (August 15, 2022): 2937. http://dx.doi.org/10.3390/math10162937.
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In this paper, fast high-order finite difference algorithms for solving the electromagnetic scattering from the finite array of two-dimensional rectangular cavities are proposed in TE polarization. The scattering problem from the cavity array is described as coupled Helmholtz equations with transparent boundary conditions on open apertures. Second-order and fourth-order schemes for solving the coupled systems are developed in TE polarization respectively. A special technique is applied to construct a fourth-order scheme for transparent boundary conditions. Further, we propose fast algorithms which can simplify the larger global system to a small linear interface system on the apertures of cavities. Numerical experiments show the validity and efficiency of the proposed fast algorithms for solving the scattering problem with high wave numbers.
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Zhu, Chenglong, Hui Chen, and Huaizong Shao. "Joint Phased-MIMO and Nested-Array Beamforming for Increased Degrees-of-Freedom." International Journal of Antennas and Propagation 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/989517.
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Phased-multiple-input multiple-output (phased-MIMO) enjoys the advantages of MIMO virtual array and phased-array directional gain, but it gets the directional gain at a cost of reduced degrees-of-freedom (DOFs). To compensate the DOF loss, this paper proposes a joint phased-array and nested-array beamforming based on the difference coarray processing and spatial smoothing. The essence is to use a nested-array in the receiver and then fully exploit the second order statistic of the received data. In doing so, the array system offers more DOFs which means more sources can be resolved. The direction-of-arrival (DOA) estimation performance of the proposed method is evaluated by examining the root-mean-square error. Simulation results show the proposed method has significant superiorities to the existing phased-MIMO.
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Touafek, Nouressadat. "On a general system of difference equations defined by homogeneous functions." Mathematica Slovaca 71, no. 3 (June 1, 2021): 697–720. http://dx.doi.org/10.1515/ms-2021-0014.
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Abstract The aim of this paper is to study the following second order system of difference equations $$\begin{array}{} x_{n+1} = f(y_{n},y_{n-1}),\quad y_{n+1} = g(x_{n},x_{n-1}) \end{array}$$ where n ∈ ℕ0, the initial values x −1, x 0, y −1 and y 0 are positive real numbers, the functions f, g : (0, +∞)2 → (0, +∞) are continuous and homogeneous of degree zero. In this study, we establish results on local stability of the unique equilibrium point and to deal with the global attractivity, and so the global stability, some general convergence theorems are provided. Necessary and sufficient conditions on existence of prime period two solutions of our system are given. Also, a result on oscillatory solutions is proved. As applications of the obtained results, concrete models of systems of difference equations defined by homogeneous functions of degree zero are investigated. Our system generalize some existing works in the literature and our results can be applied to study new models of systems of difference equations. For interested readers, we left in the conclusion as open problems two more general systems of higher order defined by homogenous functions of degree zero.
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LIU, KUI, WEI-ZHENG YUAN, BING-HE MA, CHENG-YU JIANG, and JIN-JUN DENG. "METHOD AND SIMULATION OF THE USE OF MICRO SHEAR STRESS SENSOR ARRAY IN DETECTING BOUNDARY-LAYER SEPARATION POINT." International Journal of Information Acquisition 03, no. 01 (March 2006): 9–14. http://dx.doi.org/10.1142/s0219878906000770.
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At the boundary layer's separation point, the mean of the shear stress drops to a small value while its fluctuation increases dramatically. Based on the thermal method, we can fabricate a MEMS-based shear stress sensor array to bend with the curved surface, which can measure the shear stress profile of the boundary layer. This paper presents two methods, mean and RMS of the shear stress difference max value and the second order of the array signals difference algorithm, to calculate the location of the flow separation point. Through combination of the two methods and analyzing the 2D circular column CFD simulation data, the position of the separation point can be determined accurately.
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Shi, Sha, Haowei Zeng, Heng Yue, Changbo Ye, and Jianfeng Li. "DOA Estimation for Non-Gaussian Signals: Three-Level Nested Array and a Successive SS-MUSIC Algorithm." International Journal of Antennas and Propagation 2022 (April 7, 2022): 1–14. http://dx.doi.org/10.1155/2022/9604664.
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Direction of arrival (DOA) estimation for non-Gaussian signals using three-level nested array (THL-NA) is investigated in this paper. Motivation from larger consecutive degree of freedom (DOF) and array aperture, the THL-NA is proposed, which can take full advantages of the consecutive coarrays of TL-NA and has the closed-form expression of DOF. Specifically, firstly, the array aperture is expanded by the second order sum coarray (2-SC) of the proposed array, secondly, the nested relationship between subarrays is employed to obtain the difference coarray of 2-SC (2-DCSC), finally, a consecutive virtual array with large array aperture is obtained. Besides, a successive SS-MUSIC algorithm is proposed, which employs the spatial smoothing estimating signal parameter via rotational invariance techniques (SS-ESPRIT) algorithm and partial spectrum searching multiple signal classification (PSS-MUSIC) to obtain initial estimations and fine estimations, respectively, resulting in a better balance between computational complexity and estimation accuracy.
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Pang, Yao, Lijun Yan, Yuan Liu, Lin Tang, Rui Zhu, and Guofeng Liu. "Seismic Wave Finite-Difference Forward Modeling for Orogenic Gold Deposits." Minerals 12, no. 11 (November 19, 2022): 1465. http://dx.doi.org/10.3390/min12111465.
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The demand for deep prospecting has led to an increase in the enthusiasm for seismic techniques in mineral exploration. Reflection seismology applications in the base metal industry have achieved success. For orogenic gold deposits, however, their applicable conditions remain to be investigated. This paper simulated seismic wave propagation based on a finite-difference algorithm with an accuracy of eighth order in space and second order in time to investigate the factors influencing the reflection seismic exploration results. Then, the paper assessed the algorithm’s feasibility for orogenic gold deposits, taking the giant Zaozigou deposit in central China as an example. The forward modeling showed that the petrophysical properties, dimensions, and dip of targets significantly affected the seismic exploration results. In the Zaozigou model, shallowly dipping orebodies were well imaged with precise extension and thickness. Steeply dipping orebodies were recognized but their thickness information was lost. Steeply dipping orebodies at depth were not detectable under a surface configuration. These problems could be effectively solved by increasing the array length and using vertical seismic profiling methods. For small orebodies, multiwave and multicomponent seismic techniques offered more valuable information in terms of mineral exploration. In conclusion, it was possible to locate orogenic gold deposits using the reflection seismology method.
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Zhou, Renlong, Xiaoshuang Chen, Yingyi Xiao, Bingju Zhou, Lingxi Wu, Xiaojuan Liu, Yongyi Gao, and Jie Zhan. "Second-Order Nonlinearity in Triangular Lattice Perforated Gold Film due to Surface Plasmas Resonance." Scientific World Journal 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/284929.
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We have studied the excitation second-order nonlinearity through a triangular lattice perforated gold film instead of square lattice in many papers. Under the excitation of surface plasmas resonance effect, the second order nonlinearity exists in the noncentrosymmetric split-ring resonators arrays. Reflection of fundamental frequency wave through a triangular lattice perforated gold film is obtained. We also described the second harmonic conversion efficiencies in the second order nonlinear optical process with the spectra. Moreover, the electric field distributions of fundamental frequency above the gold film region are calculated. The light propagation through the holes results in the enhancement of the second order nonlinearity including second harmonic generation as well as the sum (difference) frequency generation.
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Wang, Tsili, and Alberto Mezzatesta. "Fast Frechet derivative calculation using an auxiliary source array method: An application to array resistivity measurements." GEOPHYSICS 66, no. 5 (September 2001): 1364–71. http://dx.doi.org/10.1190/1.1487082.
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Frechet derivatives provide the vital information for parametric resistivity inversion, but the calculation for a multidimensional problem is often computer intensive. This paper presents a new technique for fast calculation of the Frechet derivatives of resistivity measurements with respect to formation resistivity properties. The technique, referred to as the auxiliary source array method (ASAM), generalizes the reciprocity principle‐based methods in that for closely spaced receivers it may not be necessary to place a fictitious source at each receiver location. Rather, an auxiliary source array comprised of sparsely spaced fictitious sources can be constructed from which the field for any fictitious source location can be reconstructed. The ASAM was tested with a deviated‐well resistivity model for an array resistivity device that acquires 8 potential, 16 first potential difference, and 14 second potential difference data points at each depth level. The Frechet derivatives calculated by the ASAM agree well with those obtained through the parameter perturbation method. The tests showed that the calculation time of the ASAM has little dependence on the number of parameters for which the Frechet derivatives are to be calculated. The method can calculate the Frechet derivatives of 5 to 138 resistivity parameters with only 20% to 50% additional computer time. For the 138‐parameter model, the ASAM is about two orders of magnitude faster than the parameter perturbation method.
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Liu, Jia-Bao, Muhammad Javaid, Mohsin Raza, and Naeem Saleem. "On minimum algebraic connectivity of graphs whose complements are bicyclic." Open Mathematics 17, no. 1 (December 10, 2019): 1490–502. http://dx.doi.org/10.1515/math-2019-0119.
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Abstract The second smallest eigenvalue of the Laplacian matrix of a graph (network) is called its algebraic connectivity which is used to diagnose Alzheimer’s disease, distinguish the group differences, measure the robustness, construct multiplex model, synchronize the stability, analyze the diffusion processes and find the connectivity of the graphs (networks). A connected graph containing two or three cycles is called a bicyclic graph if its number of edges is equal to its number of vertices plus one. In this paper, firstly the unique graph with a minimum algebraic connectivity is characterized in the class of connected graphs whose complements are bicyclic with exactly three cycles. Then, we find the unique graph of minimum algebraic connectivity in the class of connected graphs $\begin{array}{} {\it\Omega}^c_{n}={\it\Omega}^c_{1,n}\cup{\it\Omega}^c_{2,n}, \end{array}$ where $\begin{array}{} {\it\Omega}^c_{1,n} \end{array}$ and $\begin{array}{} {\it\Omega}^c_{2,n} \end{array}$ are classes of the connected graphs in which the complement of each graph of order n is a bicyclic graph with exactly two and three cycles, respectively.
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Ding, Yuzhang, Minxiang Wei, and Rui Liu. "Parameters of liquid cooling thermal management system effect on the Li-ion battery temperature distribution." Thermal Science, no. 00 (2021): 223. http://dx.doi.org/10.2298/tsci201019223d.
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In order to investigated the influence on the liquid cooling system cooling effect by changing the structural parameters, single Li-ion battery heat generation model is conducted, and used in following simulation. Subsequently, sixteen models are designed by orthogonal array, and the results are obtained by extremum difference analysis, which can quantify the influence degree, identify major and minor factors, and find the relatively optimum combination. Finally, different channel entrance layout is adopted to investigated. With a series of work, the effective of single battery heat generation model is proved by the discharge experiment. The coolant velocity has most evident influence on the Li-ion battery temperature rise, rectangular channel aspect ratio is second one, and the heat conducting plate thickness has the smallest influence. Similarly, for Li-ion battery temperature difference, the effect of heat conducting plate thickness and rectangular channel aspect ratio as the same, both are secondary factor, and coolant velocity is main factor. With different channel entrance layout, both the maximum temperatures denote a same upward trend, and better balance temperature distribution is obtained by adopt Case C system which with alternating arrange channel entrance layout.
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Chung, Kuo-Liang, Tzu-Hsien Chan, and Szu-Ni Chen. "Effective Three-Stage Demosaicking Method for RGBW CFA Images Using The Iterative Error-Compensation Based Approach." Sensors 20, no. 14 (July 14, 2020): 3908. http://dx.doi.org/10.3390/s20143908.
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As the color filter array (CFA)2.0, the RGBW CFA pattern, in which each CFA pixel contains only one R, G, B, or W color value, provides more luminance information than the Bayer CFA pattern. Demosaicking RGBW CFA images I R G B W is necessary in order to provide high-quality RGB full-color images as the target images for human perception. In this letter, we propose a three-stage demosaicking method for I R G B W . In the first-stage, a cross shape-based color difference approach is proposed in order to interpolate the missing W color pixels in the W color plane of I R G B W . In the second stage, an iterative error compensation-based demosaicking process is proposed to improve the quality of the demosaiced RGB full-color image. In the third stage, taking the input image I R G B W as the ground truth RGBW CFA image, an I R G B W -based refinement process is proposed to refine the quality of the demosaiced image obtained by the second stage. Based on the testing RGBW images that were collected from the Kodak and IMAX datasets, the comprehensive experimental results illustrated that the proposed three-stage demosaicking method achieves substantial quality and perceptual effect improvement relative to the previous method by Hamilton and Compton and the two state-of-the-art methods, Kwan et al.’s pansharpening-based method, and Kwan and Chou’s deep learning-based method.
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Letnan Kolonel Elektronika Imat Rakhmat Hidayat, S.T., M.Eng. "SAVINGS TIME EXECUTION PRIMA NUMBERS GENERATOR USING BIT-ARRAY STRUCTURE." MULTICA SCIENCE AND TECHNOLOGY (MST) 1, no. 1 (April 13, 2021): 20–27. http://dx.doi.org/10.47002/mst.v1i1.202.
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Prime number in growth computer science of number theory and very need to yield an tool which can yield an hardware storey level effectiveness use efficiency and Existing Tools can be used to awaken regular prime number sequence pattern, structure bit-array represent containing subdividing variables method of data aggregate with every data element which have type of equal, and also can be used in moth-balls the yielded number sequence. Prime number very useful to be applied by as bases from algorithm kriptografi key public creation, hash table, best algorithm if applied hence is prime number in order to can minimize collision (collisions) will happen, in determining pattern sequence of prime number which size measure is very big is not an work easy to, so that become problems which must be searched by the way of quickest to yield sequence of prime number which size measure is very big Serial use of prosesor in seeking sequence prime number which size measure is very big less be efficient remember needing of computing time which long enough, so also plural use prosesor in seeking sequence of prime number will concerning to price problem and require software newly. So that by using generator of prime number use structure bit-array expected by difficulty in searching pattern sequence of prime number can be overcome though without using plural processor even if, as well as time complexity minimization can accessed. Execution time savings gained from the research seen from the research data, using the algorithm on the input Atkins 676,999,999. 4235747.00 execution takes seconds. While the algorithm by using an array of input bits 676,999,999. 13955.00 execution takes seconds. So that there is a difference of execution time for 4221792.00 seconds.
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Han, Aoxue, Colm Dineen, Viktoriia E. Babicheva, and Jerome V. Moloney. "Second harmonic generation in metasurfaces with multipole resonant coupling." Nanophotonics 9, no. 11 (July 5, 2020): 3545–56. http://dx.doi.org/10.1515/nanoph-2020-0193.
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AbstractWe report on the numerical demonstration of enhanced second harmonic generation (SHG) originating from collective resonances in plasmonic nanoparticle arrays. The nonlinear optical response of the metal nanoparticles is modeled by employing a hydrodynamic nonlinear Drude model implemented into Finite-Difference Time-Domain (FDTD) simulations, and effective polarizabilities of nanoparticle multipoles in the lattice are analytically calculated at the fundamental wavelength by using a coupled dipole–quadrupole approximation. Excitation of narrow collective resonances in nanoparticle arrays with electric quadrupole (EQ) and magnetic dipole (MD) resonant coupling leads to strong linear resonance enhancement. In this work, we analyze SHG in the vicinity of the lattice resonance corresponding to different nanoparticle multipoles and explore SHG efficiency by varying the lattice periods. Coupling of electric quadrupole and magnetic dipole in the nanoparticle lattice indicates symmetry breaking and the possibility of enhanced SHG under these conditions. By varying the structure parameters, we can change the strength of electric dipole (ED), EQ, and MD polarizabilities, which can be used to control the linewidth and magnitude of SHG emission in plasmonic lattices. Engineering of lattice resonances and associated magnetic dipole resonant excitations can be used for spectrally narrow nonlinear response as the SHG can be enhanced and controlled by higher multipole excitations and their lattice resonances. We show that both ED and EQ–MD lattice coupling contribute to SHG, but the presence of strong EQ–MD coupling is important for spectrally narrow SHG and, in our structure, excitation of narrow higher-order multipole lattice resonances results in five times enhancement.
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Trebotich, D., G. H. Miller, and M. D. Bybee. "A Penalty Method to Model Particle Interactions in DNA-Laden Flows." Journal of Nanoscience and Nanotechnology 8, no. 7 (July 1, 2008): 3749–56. http://dx.doi.org/10.1166/jnn.2008.18340.
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We present a hybrid fluid-particle algorithm to simulate flow and transport of DNA-laden fluids in microdevices. Relevant length scales in microfluidic systems range from characteristic channel sizes of millimeters to micron scale geometric variation (e.g., post arrays) to 10 nanometers for the length of a single rod in a bead-rod polymer representation of a biological material such as DNA. The method is based on a previous fluid-particle algorithm in which long molecules are represented as a chain of connected rods, but in which the physically unrealistic behavior of rod crossing occurred. We have extended this algorithm to include screened Coulombic forces between particles by implementing a Debye-Hückel potential acting between rods. In the method an unsteady incompressible Newtonian fluid is discretized with a second-order finite difference method in the interior of the Cartesian grid domain; an embedded boundary volume-of-fluid formulation is used near boundaries. The bead-rod polymer model is fully coupled to the solvent through body forces representing hydrodynamic drag and stochastic thermal fluctuations. While intra-polymer interactions are modeled by a soft potential, polymer-structure interactions are treated as perfectly elastic collisions. We demonstrate this method on flow and transport of a polymer through a post array microchannel in 2D where the polymer incorporates more realistic physical parameters of DNA, and compare to previous simulations where rods are allowed to cross. We also show that the method is capable of simulating 3D flow in a packed bed micro-column.
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Fernandez, Vicente I., Audrey Maertens, Frank M. Yaul, Jason Dahl, Jeffrey H. Lang, and Michael S. Triantafyllou. "Lateral-Line-Inspired Sensor Arrays for Navigation and Object Identification." Marine Technology Society Journal 45, no. 4 (July 1, 2011): 130–46. http://dx.doi.org/10.4031/mtsj.45.4.20.
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AbstractThe lateral line is a critical component of fish sensory systems, found to affect numerous aspects of behavior, including maneuvering in complex fluid environments with poor visibility. This sensory organ has no analog in modern ocean vehicles, despite its utility and ubiquity in nature, and could fill the gap left by sonar and vision systems in turbid, cluttered environments.To emulate the lateral line and characterize its object-tracking and shape recognition capabilities, a linear array of pressure sensors is used along with analytic models of the fluid in order to determine position, shape, and size of various objects in both passive and active sensing schemes. We find that based on pressure information, tracking a moving cylinder can be effectively achieved via a particle filter. Using principal component analysis, we are also able to reliably distinguish between cylinders of different cross section and identify the critical flow signature information that leads to the shape identification. In a second application, we employ pressure measurements on an artificial fish and an unscented Kalman filter to successfully identify the shape of an arbitrary static cylinder.Based on the experiments, we conclude that a linear pressure sensor array for identifying small objects should have a sensor-to-sensor spacing of less than 0.03 (relative to the length of the sensing body) and resolve pressure differences of at least 10 Pa. These criteria are used in the development of an artificial lateral line adaptable to the curved hull of an underwater vehicle, employing conductive polymer technologies to form a flexible array of small pressure sensors.
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Krysko, V. A., I. V. Papkova, I. E. Kutepov, and A. V. Krysko. "VIBRATIONS OF A BEAM IN A FIELD OF COLOR NOISE." Problems of strenght and plasticity 81, no. 1 (2019): 53–62. http://dx.doi.org/10.32326/1814-9146-2019-81-1-53-62.
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An attempt is made to clear vibrations of a beam resting on a viscoelastic support from noise effects. It is assumed that Bernoulli-Euler hypothesis holds. Effects of white, red, pink, purple and blue noise are considered. Noise is accounted for as a component of an alternating distributed load. Equations of motion of the beam areobtained as partial derivatives from Hamilton-Ostrogradski principle. Partial derivative equations are reduced to a Cauchy problem, using a second-order accuracy finite difference method, which is solved by Runge-Kutta-type methods. To clear vibrations of the beam from noise, the main component method was applied. This method was used to process the solutions of linear partial differential equations describing vibrations of rectangular beams resting on a viscoelastic support. Solutions of the equations were represented in the form of a 2D data array corresponding to deflections in the nodes of the beam at different times. The quality of clearing was assessed by comparing the Fourier power spectra obtained in the absence of noise effects with those that had noise effects, and after clearing. Problems for beams simply supported at both ends, fully fixed at both ends, simply supported at one end and fully fixed at the other one are considered. It was possible to clear the signals from four types of noise: white, pink, blue and purple.
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Petrov, Petr V., and Gregory A. Newman. "Estimation of seismic source parameters in 3D elastic media using the reciprocity theorem." GEOPHYSICS 84, no. 6 (November 1, 2019): R963—R976. http://dx.doi.org/10.1190/geo2018-0283.1.
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We have developed a novel method based upon reciprocity principles to simultaneously estimate the location of a seismic event and its source mechanism in 3D heterogeneous media. The method finds double-couple (DC) and non-DC mechanisms of microearthquakes arising from localized induced and natural seismicity. Because the method uses an exhaustive search of the 3D elastic media, it is globally convergent. It does not suffer from local minima realization observed with local optimization methods, including Newton, Gauss-Newton, or gradient-descent algorithms. The computational efficiency of our scheme is derived from the reciprocity principle, in which the number of 3D model realizations corresponds to the number of measurement receivers. The 3D forward modeling is carried out in the damped Fourier domain with a 3D finite-difference frequency-domain fourth- and second-order code developed to simulate elastic waves generated by seismic sources defined by forces and second-order moment density tensors. We evaluate the results of testing this new methodology on synthetic data for the Raft River geothermal field, Idaho, as well as determine its applicability in designing optimal borehole monitoring arrays in a fracking experiment at the Homestake Mine, South Dakota. We also find that the method proposed here can retrieve the moment tensors of the space distributed source with data arising from spatially restricted arrays with limited aperture. The effects of uncertainties on the source parameter estimation are also examined with respect to data noise and model uncertainty.
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Лаврентьев, М. М., К. Ф. Лысаков, А. Г. Марчук, and К. К. Облаухов. "FPGA Fast Simulation of Tsunami Wave Propagation." Успехи кибернетики / Russian Journal of Cybernetics, no. 1(5) (June 30, 2021): 14–25. http://dx.doi.org/10.51790/2712-9942-2021-2-1-2.
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В данной статье рассматривается решение задачи быстрой численной оценки высоты волн цунами от гипотетического очага вдоль тихоокеанского побережья полуострова Камчатка и Курильских островов. Мы фокусируемся на очень быстром (практически в режиме поступления данных) численном моделировании распространения волны цунами на основе ПК в соответствии с классическим приближением теории мелкой воды. Существенный прирост производительности достигается за счет использования преимуществ современных компьютерных архитектур, а именно вентильных матриц, программируемых пользователем (Field Programmable Gate Array – FPGA). Разностная схема Мак-Кормака второго порядка аппроксимации для решения системы дифференциальных уравнений мелкой воды [1] реализована на чипе FPGA в составе платы, специально разработанной авторами для решения этой задачи [2, 3]. Численные тесты показывают, что для расчета 3600 шагов по времени распространения волны цунами в расчетной области размером приблизительно 2000х2000 км (3120х2400 расчетных узлов) требуется всего несколько секунд для моделирования цунами от модельного источника волны цунами на сетке с пространственным шагом около 900 м. Созданный на базе FPGA спецвычислитель был также протестирован по точности сравнением с аналитическими решениями, полученными Ан. Марчуком [4, 5] для некоторых модельных топографий дна. The study offers a fast quantitative estimation of tsunami wave heights coming from a hypothetical source along the Pacific coast of the Kamchatka Peninsula and the Kuril Islands. We focus on a very fast (virtually real-time) PC simulation of tsunami wave propagation using the classical approximation of the shallow water theory. Significant performance gains are achieved by taking advantage of modern computer architectures, namely Field Programmable Gate Arrays (FPGAs). The McCormack difference scheme of the second order of approximation for solving the system of shallow water differential equations [1] is implemented with an FPGA chip on a custom PCB designed by the authors [2, 3]. Numerical tests indicate that it takes only a few seconds to simulate a tsunami wave from a simulated source on a 900 m spacing grid to analyze 3,600 time increments of propagation of the tsunami wave propagation in about 2000x2000 km area (3,120x2,400 nodes.) The customized FPGA computer was also tested for accuracy by comparing with the analytical solutions obtained by Marchuk [4, 5] for some reference bottom topographies.
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Qiu, Meilan, Dewang Li, and Yanyun Wu. "Local Discontinuous Galerkin Method for Nonlinear Time-Space Fractional Subdiffusion/Superdiffusion Equations." Mathematical Problems in Engineering 2020 (June 22, 2020): 1–21. http://dx.doi.org/10.1155/2020/6954239.
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Fractional partial differential equations with time-space fractional derivatives describe some important physical phenomena. For example, the subdiffusion equation (time order 0<α<1) is more suitable to describe the phenomena of charge carrier transport in amorphous semiconductors, nuclear magnetic resonance (NMR) diffusometry in percolative, Rouse, or reptation dynamics in polymeric systems, the diffusion of a scalar tracer in an array of convection rolls, or the dynamics of a bead in a polymeric network, and so on. However, the superdiffusion case (1<α<2) is more accurate to depict the special domains of rotating flows, collective slip diffusion on solid surfaces, layered velocity fields, Richardson turbulent diffusion, bulk-surface exchange controlled dynamics in porous glasses, the transport in micelle systems and heterogeneous rocks, quantum optics, single molecule spectroscopy, the transport in turbulent plasma, bacterial motion, and even for the flight of an albatross (for more physical applications of fractional sub-super diffusion equations, one can see Metzler and Klafter in 2000). In this work, we establish two fully discrete numerical schemes for solving a class of nonlinear time-space fractional subdiffusion/superdiffusion equations by using backward Euler difference 1<α<2 or second-order central difference 1<α<2/local discontinuous Galerkin finite element mixed method. By introducing the mathematical induction method, we show the concrete analysis for the stability and the convergence rate under the L2 norm of the two LDG schemes. In the end, we adopt several numerical experiments to validate the proposed model and demonstrate the features of the two numerical schemes, such as the optimal convergence rate in space direction is close to Ohk+1. The convergence rate in time direction can arrive at Oτ2−α when the fractional derivative is 0<α<1. If the fractional derivative parameter is 1<α<2 and we choose the relationship as h=C′τ (h denotes the space step size, C′ is a constant, and τ is the time step size), then the time convergence rate can reach to Oτ3−α. The experiment results illustrate that the proposed method is effective in solving nonlinear time-space fractional subdiffusion/superdiffusion equations.
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Tejedor Sastre, María Teresa, and Christian Vanhille. "Nonlinear Maximization of the Sum-Frequency Component from Two Ultrasonic Signals in a Bubbly Liquid." Sensors 20, no. 1 (December 23, 2019): 113. http://dx.doi.org/10.3390/s20010113.
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Techniques based on ultrasound in nondestructive testing and medical imaging analyze the response of the source frequencies (linear theory) or the second-order frequencies such as higher harmonics, difference and sum frequencies (nonlinear theory). The low attenuation and high directivity of the difference-frequency component generated nonlinearly by parametric arrays are useful. Higher harmonics created directly from a single-frequency source and the sum-frequency component generated nonlinearly by parametric arrays are attractive because of their high spatial resolution and accuracy. The nonlinear response of bubbly liquids can be strong even at relatively low acoustic pressure amplitudes. Thus, these nonlinear frequencies can be generated easily in these media. Since the experimental study of such nonlinear waves in stable bubbly liquids is a very difficult task, in this work we use a numerical model developed previously to describe the nonlinear propagation of ultrasound interacting with nonlinearly oscillating bubbles in a liquid. This numerical model solves a differential system coupling a Rayleigh–Plesset equation and the wave equation. This paper performs an analysis of the generation of the sum-frequency component by nonlinear mixing of two signals of lower frequencies. It shows that the amplitude of this component can be maximized by taking into account the nonlinear resonance of the system. This effect is due to the softening of the medium when pressure amplitudes rise.
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Chen, Yangjun, and Hoang Hai Nguyen. "On the string matching with k differences in DNA databases." Proceedings of the VLDB Endowment 14, no. 6 (February 2021): 903–15. http://dx.doi.org/10.14778/3447689.3447695.
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In this paper, we discuss an efficient and effective index mechanism for the string matching with k differences, by which we will find all the substrings of a target string y of length n that align with a pattern string x of length m with not more than k insertions, deletions, and mismatches. A typical application is the searching of a DNA database, where the size of a genome sequence in the database is much larger than that of a pattern. For example, n is often on the order of millions or billions while m is just a hundred or a thousand. The main idea of our method is to transform y to a BWT-array as an index, denoted as BWT ( y ), and search x against it. The time complexity of our method is bounded by O( k · | T |), where T is a tree structure dynamically generated during a search of BWT ( y ). The average value of | T | is bounded by O(|Σ| 2 k ), where Σ is an alphabet from which we take symbols to make up target and pattern strings. This time complexity is better than previous strategies when k ≤ O(log |Σ| n ). The general working process consists of two steps. In the first step, x is decomposed into a series of l small subpatterns, and BWT ( y ) is utilized to speedup the process to figure out all the occurrences of such subpatterns with ⌊ k/l ⌋ differences. In the second step, all the found occurrences in the first step will be rechecked to see whether they really match x , but with k differences. Extensive experiments have been conducted, which show that our method for this problem is promising.
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Pfeil, Hannah, Abram Hindle, and Hazel Campbell. "Amazing Grace: How Sweet the Sound of Synthesised Bagpipes." Alberta Academic Review 2, no. 2 (September 18, 2019): 59–60. http://dx.doi.org/10.29173/aar65.
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A bagpipe is a type of wind instrument that contains a melody pipe, which has an enclosed reed called the chanter and other drone pipes. The chanter is the part of the bagpipe that supplies the note, and the air that the pipes are fed is provided by the bag, which is inflated by a blowpipe and driven by the player’s arm. The goal of this project was to create a bagpipe using a program called Supercollider. Supercollider is used for audio synthesis. While creating this artificial bagpipe (here on referred to as a ‘synth’), it was broken down into four components: the chanter, the base drone, the first tenor drone and the second tenor drone. The chanter has the frequency of the note, the base drone’s frequency will be half that of the chanter and the frequency of the tenor drone will be half that of the base drone. This is because of the length of the pipes in relation to each other. In order to create the synth, a sine oscillator was used, and then put through a resonance filter, and then a reverb filter. This was done in order to mimic the echo that sound has when it is forced through a tube, or enclosed space. All four pipes were added together to create the synth. In order to play a song, the synth was put into a pattern so Supercollider could receive an array of notes, which serve as the frequency of the chanter, and then play the song automatically. The notes for Amazing Grace were transcribed into midi-notes and beat durations and these arrays were fed into the pattern to create the song. The synthetic version of Amazing Grace, in terms of frequency and loudness, was then graphed and compared to the graph of a recording of Amazing Grace played on a real bagpipe. There are differences between the two sound files, the most significant being that the real bagpipe has much more variation in terms of loudness. The synthesized bagpipe had a more gradual and subdued noise level, where the natural bagpipe was much more randomized. Taking the comparisons into consideration, Supercollider can be used to create an approximation of a bagpipe, but under scrutiny, the artificial version currently falls short.
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Mitsa, Alexander, Petr Stetsyuk, Alexander Levchuk, Vasily Petsko, and Igor Povkhan. "ON THE ACCELERATION OF OPTIMIZATION METHODS FOR THE PROBLEM OF SYNTHESIS OF MULTILAYER OPTICAL COATINGS." Journal of Automation and Information sciences 6 (November 1, 2021): 13–26. http://dx.doi.org/10.34229/1028-0979-2021-6-2.
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Five ways to speed up the multidimensional search in order to solve the problem of synthesis of multilayer optical coatings by using the methods of zero and first orders have been considered. The first way is to use an analytical derivative for the target quality function of the multilayer coating. It allows us to calculate accurately (within the computer arithmetic) the value of the gradient of a smooth objective function and generalized gradient of a non-smooth objective one. The first way requires the same number of arithmetic operations as well as finite-difference methods of calculating the gradient and the generalized gradient. The second way is to use a speedy finding of the objective function gradient using the prefix- and suffix-arrays in the analytical method of calculating the gradient. This technique allows us to reduce the number of arithmetic operations thrice for large-scale problems. The third way is the use of tabulating the values of trigonometric functions to calculate the characteristic matrices. This technique reduces the execution time of multiplication operations of characteristic matrices ten times depending on the computer’s specifications. For some computer architectures, this advantage is more than 140 times. The fourth method is the use of the golden section method for the one-dimensional optimization in the problems of synthesis of optical coatings. In particular, when solving one partial problem it is shown that the ternary search method requires approximately 40% more time than the golden section method. The fifth way is to use the effective implementation of multiplication of two matrices. It lies in changing the order of the second and third cycles for the well-known method of multiplying two matrices and fixing in a common variable value of the element of the first matrix. This allows us to speed up significantly the multiplication operation of two matrices. For matrices having 1000 x 1000 dimension the acceleration is from 2 to 15 times, depending on the computer's specifications.
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Parkes, Rebecca S. V., Thilo Pfau, Renate Weller, and Thomas H. Witte. "The effect of curve running on distal limb kinematics in the Thoroughbred racehorse." PLOS ONE 15, no. 12 (December 29, 2020): e0244105. http://dx.doi.org/10.1371/journal.pone.0244105.
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During racing, injury is more likely to occur on a bend than on a straight segment of track. This study aimed to quantify the effects of galloping at training speeds on large radius curves on stride parameters and limb lean angle in order to assess estimated consequences for limb loading. Seven Thoroughbred horses were equipped with a sacrum-mounted inertial measurement unit with an integrated GPS, two hoof-mounted accelerometers and retro-reflective markers on the forelimbs. Horses galloped 2–4 circuits anticlockwise around an oval track and were filmed at 120 frames per second using an array of ten cameras. Speed and curve radius were derived from GPS data and used to estimate the centripetal acceleration necessary to navigate the curve. Stride, stance and swing durations and duty factor (DF) were derived from accelerometer data. Limb markers were tracked and whole limb and third metacarpus (MCIII) angles were calculated. Data were analysed using mixed effects models with a significance level of p < 0.05. For horses galloping on the correct lead, DF was higher for the inside (lead) leg on the straight and on the curve. For horses galloping on the incorrect lead, there was no difference in DF between inside and outside legs on the straight or on the curve. DF decreased by 0.61% of DF with each 1 m s-2 increase in centripetal acceleration (p < 0.001). Whole limb inclination angle increased by 1.5° per 1 m s-1 increase in speed (p = 0.002). Limb lean angles increase as predicted, and lead limb function mirrors the functional requirements for curve running. A more comprehensive understanding of the effects of lean and torque on the distal limb is required to understand injury mechanisms.
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Craft, Michelle F., Andrea K. Barreiro, Shree Hari Gautam, Woodrow L. Shew, and Cheng Ly. "Differences in olfactory bulb mitral cell spiking with ortho- and retronasal stimulation revealed by data-driven models." PLOS Computational Biology 17, no. 9 (September 20, 2021): e1009169. http://dx.doi.org/10.1371/journal.pcbi.1009169.
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The majority of olfaction studies focus on orthonasal stimulation where odors enter via the front nasal cavity, while retronasal olfaction, where odors enter the rear of the nasal cavity during feeding, is understudied. The coding of retronasal odors via coordinated spiking of neurons in the olfactory bulb (OB) is largely unknown despite evidence that higher level processing is different than orthonasal. To this end, we use multi-electrode array in vivo recordings of rat OB mitral cells (MC) in response to a food odor with both modes of stimulation, and find significant differences in evoked firing rates and spike count covariances (i.e., noise correlations). Differences in spiking activity often have implications for sensory coding, thus we develop a single-compartment biophysical OB model that is able to reproduce key properties of important OB cell types. Prior experiments in olfactory receptor neurons (ORN) showed retro stimulation yields slower and spatially smaller ORN inputs than with ortho, yet whether this is consequential for OB activity remains unknown. Indeed with these specifications for ORN inputs, our OB model captures the salient trends in our OB data. We also analyze how first and second order ORN input statistics dynamically transfer to MC spiking statistics with a phenomenological linear-nonlinear filter model, and find that retro inputs result in larger linear filters than ortho inputs. Finally, our models show that the temporal profile of ORN is crucial for capturing our data and is thus a distinguishing feature between ortho and retro stimulation, even at the OB. Using data-driven modeling, we detail how ORN inputs result in differences in OB dynamics and MC spiking statistics. These differences may ultimately shape how ortho and retro odors are coded.
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Elko, Gary W., and Heinz Teutsch. "Second-order adaptive differential microphone array." Journal of the Acoustical Society of America 115, no. 1 (2004): 14. http://dx.doi.org/10.1121/1.1646972.
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Jaruga, A., S. Arabas, D. Jarecka, H. Pawlowska, P. K. Smolarkiewicz, and M. Waruszewski. "libmpdata++ 0.1: a library of parallel MPDATA solvers for systems of generalised transport equations." Geoscientific Model Development Discussions 7, no. 6 (November 26, 2014): 8179–273. http://dx.doi.org/10.5194/gmdd-7-8179-2014.
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Abstract. This paper accompanies first release of libmpdata++, a C++ library implementing the Multidimensional Positive-Definite Advection Transport Algorithm (MPDATA). The library offers basic numerical solvers for systems of generalised transport equations. The solvers are forward-in-time, conservative and non-linearly stable. The libmpdata++ library covers the basic second-order-accurate formulation of MPDATA, its third-order variant, the infinite-gauge option for variable-sign fields and a flux-corrected transport extension to guarantee non-oscillatory solutions. The library is equipped with a non-symmetric variational elliptic solver for implicit evaluation of pressure gradient terms. All solvers offer parallelisation through domain decomposition using shared-memory parallelisation. The paper describes the library programming interface, and serves as a user guide. Supported options are illustrated with benchmarks discussed in the MPDATA literature. Benchmark descriptions include code snippets as well as quantitative representations of simulation results. Examples of applications include: homogeneous transport in one, two and three dimensions in Cartesian and spherical domains; shallow-water system compared with analytical solution (originally derived for a 2-D case); and a buoyant convection problem in an incompressible Boussinesq fluid with interfacial instability. All the examples are implemented out of the library tree. Regardless of the differences in the problem dimensionality, right-hand-side terms, boundary conditions and parallelisation approach, all the examples use the same unmodified library, which is a key goal of libmpdata++ design. The design, based on the principle of separation of concerns, prioritises the user and developer productivity. The libmpdata++ library is implemented in C++, making use of the Blitz++ multi-dimensional array containers, and is released as free/libre and open-source software.
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Becnel, Melody R., M. Laura Rubin, Ranjit Nair, Elisabet E. Manasanch, Hans C. Lee, Krina K. Patel, Swaminathan P. Iyer, Sheeba K. Thomas, Donna M. Weber, and Robert Z. Orlowski. "Effect of Timing of Monoclonal Antibody Therapy on the Time to Next Treatment and Response Rate in Heavily Pre-Treated Patients with Myeloma Who Separately Received Both Daratumumab and Elotuzumab-Based Regimens." Blood 132, Supplement 1 (November 29, 2018): 3258. http://dx.doi.org/10.1182/blood-2018-99-115663.
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Abstract Introduction Notable advances have been made in multiple myeloma management (MM) in recent years. The monoclonal antibodies daratumumab (dara) and elotuzumab (elo) are integral in the management of relapsed/refractory MM and are moving into the frontline setting for transplant ineligible patients. Despite many trials evaluating the efficacy of these agents, there is no consensus on the optimal integration of these agents into the current paradigm of MM management. There is a paucity of data to guide the selection of one antibody over the other, and little is known about whether the use of one prior antibody alters the efficacy of other agents in subsequent lines of therapy. We retrospectively analyzed MM patients treated with both elo and dara during the course of their disease to assess whether the sequence of elo followed by dara or dara followed by elo led to better outcomes. Methods We reviewed the records of MM patients ≥ 18 years old who received both dara and elo at any time during treatment at MD Anderson Cancer Center. We evaluated the time to next treatment (TTNT), defined as the start date of one treatment to the start of the next treatment, and the overall response rate (ORR) (partial response or greater) to dara and elo. TTNT and ORR were calculated for dara when administered as the first antibody during treatment and to dara when administered as the second antibody (elo given during prior lines of treatment). We evaluated TTNT and ORR when elo was administered as the first antibody during treatment and to elo when administered as the second antibody (dara given during prior lines of treatment). The association with categorical patient variables (age, race, immunoglobulin class, number of prior lines of therapy, agent co-administered with the second monoclonal antibody given) was analyzed using Fisher exact tests. Outcomes were estimated using the Kaplan-Meier method and differences in survival among groups were assessed using two-sided log-rank tests. Results We identified 56 patients treated with both dara and elo. We excluded 6 for missing data; 56% of the 50 patients were male; 70% were Caucasian; 56% with IgG subclass paraprotein; 66% kappa light chain restricted. Patients were heavily pre-treated; most with >5 lines of therapy prior to initiation of dara or elo. Elo was the first agent received in 64% of patients. Independent of treatment order, the ORR to elo and dara were 72% and 88% respectively. When elo was administered prior to dara (elo first), the ORR was 78%, and 61% when administered after dara (elo second). When dara was administered prior to elo (dara first), the ORR was 89%, and 88% when administered after elo (dara second). There was no statistical difference in ORR (78% vs 89%) for the initial antibody given, but there was a significant difference in ORR (61% vs. 88%) to the agent given second (p=0.04). Of the variables assessed, only the antibody class had a statistically significant association with outcomes; IgG was associated with better responses when elo was administered as the second agent. TTNT analysis included 47 (of 50) evaluable patients. With elo given first, median TTNT was 6.28 months, and 2.23 months when given second. With dara given first, median TTNT was 8.97 months and 4.60 months when given second. There was no statistically significant difference in TTNT for either the first or second agent administered. There was a statistically significant improvement in TTNT in Caucasian patients compared to other races when elo was given first, but no other clinical factor association was statistically significant. Conclusions Our data, though retrospective and single-center, demonstrate that responses to dara are similar whether administered as the first or second monoclonal antibody used in the treatment of MM. However, prior treatment with dara negatively impacts responses to elo in subsequent lines of therapy. Similarly, independent of the sequence of administration, TTNT was prolonged with dara compared to elo. Our findings suggest that elo followed by dara may be the preferred sequence of monoclonal antibody therapy as responses to elo decreased when administered after dara, but responses to dara were stable irrespective of elo administration. These findings warrant further investigation particularly as dara is now being used more often in the frontline setting. Further evaluation is also needed to determine any association with additional patient factors such as cytogenetics. Disclosures Lee: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies Corporation: Consultancy; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Chugai Biopharmaceuticals: Consultancy; Takeda Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees. Patel:Poseida Therapeutics, Inc.: Research Funding; Takeda: Research Funding; Abbvie: Research Funding; Celgene: Research Funding. Thomas:Amgen Inc: Research Funding; Celgene: Research Funding; Bristol Myers Squibb Inc.: Research Funding; Array Pharma: Research Funding; Acerta Pharma: Research Funding. Orlowski:Janssen Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioTheryX, Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millenium Pharmaceuticals: Consultancy, Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Consultancy; Poseida: Research Funding.
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Jaruga, A., S. Arabas, D. Jarecka, H. Pawlowska, P. K. Smolarkiewicz, and M. Waruszewski. "libmpdata++ 1.0: a library of parallel MPDATA solvers for systems of generalised transport equations." Geoscientific Model Development 8, no. 4 (April 8, 2015): 1005–32. http://dx.doi.org/10.5194/gmd-8-1005-2015.
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Abstract. This paper accompanies the first release of libmpdata++, a C++ library implementing the multi-dimensional positive-definite advection transport algorithm (MPDATA) on regular structured grid. The library offers basic numerical solvers for systems of generalised transport equations. The solvers are forward-in-time, conservative and non-linearly stable. The libmpdata++ library covers the basic second-order-accurate formulation of MPDATA, its third-order variant, the infinite-gauge option for variable-sign fields and a flux-corrected transport extension to guarantee non-oscillatory solutions. The library is equipped with a non-symmetric variational elliptic solver for implicit evaluation of pressure gradient terms. All solvers offer parallelisation through domain decomposition using shared-memory parallelisation. The paper describes the library programming interface, and serves as a user guide. Supported options are illustrated with benchmarks discussed in the MPDATA literature. Benchmark descriptions include code snippets as well as quantitative representations of simulation results. Examples of applications include homogeneous transport in one, two and three dimensions in Cartesian and spherical domains; a shallow-water system compared with analytical solution (originally derived for a 2-D case); and a buoyant convection problem in an incompressible Boussinesq fluid with interfacial instability. All the examples are implemented out of the library tree. Regardless of the differences in the problem dimensionality, right-hand-side terms, boundary conditions and parallelisation approach, all the examples use the same unmodified library, which is a key goal of libmpdata++ design. The design, based on the principle of separation of concerns, prioritises the user and developer productivity. The libmpdata++ library is implemented in C++, making use of the Blitz++ multi-dimensional array containers, and is released as free/libre and open-source software.
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Encinas, A. M., and M. J. Jiménez. "Second order linear difference equations." Journal of Difference Equations and Applications 24, no. 3 (December 4, 2017): 305–43. http://dx.doi.org/10.1080/10236198.2017.1408608.
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Lin, Yue, Jun Su, Qi Qiu, Zhiqiang Fan, Shuangjin Shi, Yunxiang Wang, Di Jiang, Yuan Chen, and Xiang Li. "Reconfigurable Multi-Beam Receiver Based on Microwave Photonics Technology." Applied Sciences 13, no. 3 (January 20, 2023): 1422. http://dx.doi.org/10.3390/app13031422.
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A novel multi-beam photonic receiver with a variable beam count has been proposed. The reconfigurable characteristic of the system is enabled with the variable splitters and optical switch arrays. According to the number of beams it is due to receive, the splitter with suitable ports is chosen to split by controlling the optical switch in order to configure the optical path. After splitting, the multi-wavelength optical carriers are sent to the wavelength division multiplexer to combine and complete the multi-beamforming process. Two structures have been designed to realize the reconfigurable function, while the optimized structure is proved by using several benchmarks for comparison. The operation step of the reconfigurable multi-beam receiver is then given. The first simulations validate that the proposed architecture can dynamically receive the multi-beam with a variable number by reconfiguring the state of the optical switch. The second simulation of the influence on the received beam pattern was performed under a different amplitude and phase inconsistency random values. The results show that the amplitude and phase inconsistency will decline the quality of the multi-beam. When the amplitude and phase inconsistency are within limits, the difference in the optical path within the outputs must be balanced and compensated during the proposed system’s fabrication and deployment.
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Warren, Daniel M. "Microphone array having a second order directional pattern." Journal of the Acoustical Society of America 128, no. 6 (2010): 3819. http://dx.doi.org/10.1121/1.3544371.
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Pesavento, M., A. B. Gershman, and Zhi-Quan Luo. "Robust array interpolation using second-order cone programming." IEEE Signal Processing Letters 9, no. 1 (January 2002): 8–11. http://dx.doi.org/10.1109/97.988716.
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Warren, Daniel Max, and Stephen C. Thompson. "Microphone array having a second order directional pattern." Journal of the Acoustical Society of America 120, no. 6 (2006): 3439. http://dx.doi.org/10.1121/1.2409396.
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Yaying, Taja, and Bipan Hazarika. "On sequence spaces generated by binomial difference operator of fractional order." Mathematica Slovaca 69, no. 4 (August 27, 2019): 901–18. http://dx.doi.org/10.1515/ms-2017-0276.
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Abstract In this article we introduce binomial difference sequence spaces of fractional order α, $\begin{array}{} b_p^{r,s} \end{array}$ (Δ(α)) (1 ≤ p ≤ ∞) by the composition of binomial matrix, Br,s and fractional difference operator Δ(α), defined by (Δ(α)x)k = $\begin{array}{} \displaystyle \sum\limits_{i=0}^{\infty}(-1)^i\frac{\Gamma(\alpha+1)}{i!\Gamma(\alpha-i+1)}x_{k-i} \end{array}$. We give some topological properties, obtain the Schauder basis and determine the α, β and γ-duals of the spaces. We characterize the matrix classes ( $\begin{array}{} b_p^{r,s} \end{array}$(Δ(α)), Y), where Y ∈ {ℓ∞, c, c0, ℓ1} and certain classes of compact operators on the space $\begin{array}{} b_p^{r,s} \end{array}$(Δ(α)) using Hausdorff measure of non-compactness. Finally, we give some geometric properties of the space $\begin{array}{} b_p^{r,s} \end{array}$(Δ(α)) (1 < p < ∞).
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Huang, Ying, Jingjing Wang, and Tongxing Li. "Oscillation of second-order difference equations." Journal of Nonlinear Sciences and Applications 10, no. 03 (March 29, 2017): 1238–43. http://dx.doi.org/10.22436/jnsa.010.03.32.
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Yonekawa, Riku, Yuji Inagaki, Eri Ioka, Yasuhide Takase, and Yasuyuki Matsuya. "Second-order Predictive ADC using a Capacitor Array DAC." IEEJ Transactions on Electronics, Information and Systems 138, no. 1 (2018): 29–36. http://dx.doi.org/10.1541/ieejeiss.138.29.
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Rehman, Tanzeel U., Libo Zhang, Dongdong Ma, and Jian Jin. "Common Latent Space Exploration for Calibration Transfer across Hyperspectral Imaging-Based Phenotyping Systems." Remote Sensing 14, no. 2 (January 11, 2022): 319. http://dx.doi.org/10.3390/rs14020319.
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Hyperspectral imaging has increasingly been used in high-throughput plant phenotyping systems. Rapid advancement in the field of phenotyping has resulted in a wide array of hyperspectral imaging systems. However, sharing the plant feature prediction models between different phenotyping facilities becomes challenging due to the differences in imaging environments and imaging sensors. Calibration transfer between imaging facilities is crucially important to cope with such changes. Spectral space adjustment methods including direct standardization (DS), its variants (PDS, DPDS) and spectral scale transformation (SST) require the standard samples to be imaged in different facilities. However, in real-world scenarios, imaging the standard samples is practically unattractive. Therefore, in this study, we presented three methods (TCA, c-PCA, and di-PLSR) to transfer the calibration models without requiring the standard samples. In order to compare the performance of proposed approaches, maize plants were imaged in two greenhouse-based HTPP systems using two pushbroom-style hyperspectral cameras covering the visible near-infrared range. We tested the proposed methods to transfer nitrogen content (N) and relative water content (RWC) calibration models. The results showed that prediction R2 increased by up to 14.50% and 42.20%, while the reduction in RMSEv was up to 74.49% and 76.72% for RWC and N, respectively. The di-PLSR achieved the best results for almost all the datasets included in this study, with TCA being second. The performance of c-PCA was not at par with the di-PLSR and TCA. Our results showed that the di-PLSR helped to recover the performance of RWC, and N models plummeted due to the differences originating from new imaging systems (sensor type, spectrograph, lens system, spatial resolution, spectral resolution, field of view, bit-depth, frame rate, and exposure time) or lighting conditions. The proposed approaches can alleviate the requirement of developing a new calibration model for a new phenotyping facility or to resort to the spectral space adjustment using the standard samples.
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Apreutesei, G., and N. Apreutesei. "Second order difference inclusions of monotone type." Mathematica Bohemica 137, no. 2 (2012): 123–30. http://dx.doi.org/10.21136/mb.2012.142858.
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Cheng, Jinfa, and Yuming Chu. "OSCILLATION THEOREM FOR SECOND-ORDER DIFFERENCE EQUATIONS." Taiwanese Journal of Mathematics 12, no. 3 (June 2008): 623–33. http://dx.doi.org/10.11650/twjm/1500602425.
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Senior, Thomas B. A., and Stéphane R. Legault. "Second-order difference equations in diffraction theory." Radio Science 35, no. 3 (May 2000): 683–90. http://dx.doi.org/10.1029/1999rs002246.
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