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Computers, Materials & Continua 2019年第1期58卷 263-285页

作者： N.Jayashree R.S.Bhuvaneswaran Ramanujan Computing Centre Anna UniversityChennai600025India

Watermarking is a widely used solution to the problems of authentication and copyright protection of digital media especially for images,videos,and audio *** is one of the emerging techniques adopted in image watermarking schemes due to its intrinsic cryptographic *** paper proposes a new chaotic hybrid watermarking method combining Discrete Wavelet transform(DWT),z-transform(zT)and Bidiagonal Singular Value Decomposition(BSVD).The original image is decomposed into 3-level DWT,and then,zT is applied on the HH3 and HL3 *** watermark image is encrypted using Arnold Cat *** for the watermark and transformed original image were computed,and the watermark was embedded by modifying singular values of the host image with the singular values of the watermark *** of the proposed scheme was examined using standard test images and assessed against common signal processing and geometric *** indicated that the proposed method is transparent and highly robust.

关键词： Digital watermarking chaotic mapping z-transform arnold cat map discrete wavelet transform(DWT) bidiagonal singular value decomposition(BSVD)

z-transform Based Instantaneous Unit Hydrograph for Hilly Watersheds

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Journal of Water Resource and Protection 2009年第6期1卷 381-390页

作者： R. K. RAI C. S. P. OJHA Alka UPADHYAY 不详

Present study emphasizes the applicability of linear theory concept onto hilly watersheds. For this purpose, z-transform technique was used to derive the instantaneous unit hydrograph (IUH) from the transfer function of autoregressive and moving average (ARMA) type linear difference equation. Parameters of the ARMA type rainfall-runoff process were estimated by least-squares method. The derived IUH from z-transform (i.e. ARMA-IUH) has been used to compute the hydrologic response i.e. direct runoff hydrograph (DRH). Fur-ther, the superiority of the proposed approach has been tested by comparing the results through the results obtained from the Nash-IUH. Analyzing the results obtained from ARMA-IUH and Nash-IUH for the two hilly watersheds of North Western Himalayas shows the applicability of the linear theory concept even in turbulent flow conditions which are frequently encountered in hilly terrains under similar conditions of flow.

关键词： IUH ARMA Process z-transform Nash Model Direct Runoff Hydrograph Hilly Watershed

TIME DOMAIN ANALYSIS OF TRANSIENT PROPAGATION IN INHOMOGENEOUS MAGNETIzED PLASMA USING z-transformS

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Journal of Electronics(China) 2006年第1期23卷 113-116页

作者： Huang Shoujiang Li Fang Institute of Electronics Chinese Academy of Sciences Beo＇ing 100080 China

The electromagnetic propagation through an inhomogeneous magnetized plasma slab is studied using the z-transform formulation of the Finite-Difference Time-Domain(FDTD) method. The direction of electromagnetic propagation is parallel to the biasing magnetic filed. To validate the z-transform algorithm, the reflection and transmission coefficients for the right-hand circularly polarized wave of the homogeneous magnetized plasma slab are computed by means of discrete Fourier transform. The comparison between the reflection and transmission coefficients of the homogeneous plasma slab and analytical values indicates that z-transform algorithm is very accurate. When the plasma frequency varies according to the square root and parabolic relations, the reflection and transmission coefficients of the inhomogeneous magnetized plasma slab are computed.

关键词： Finite-Difference Time-Domain (FDTD) z-transform Magnetized plasma

Digital synthesis of programmable photonic integrated circuits

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Chinese Physics B 2022年第2期31卷 355-365页

作者： Juan zhang zhengyong Ji Yipeng Ding Yang Wang Key Laboratory of Specialty Fiber Optics and Optical Access Networks School of Communication and Information EngineeringShanghai UniversityShanghai 200444China School of Physical Science and Electronics Central South UniversityChangsha 410012China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800China

Programmable photonic waveguide meshes can be programmed into many different circuit topologies and thereby provide a variety of *** to the complexity of the signal routing in a general mesh,a particular synthesis algorithm often only accounts for a specific function with a specific cell *** this paper,we try to synthesize the programmable waveguide mesh to support multiple configurations with a more general digital signal processing *** show the feasibility of this technique,photonic waveguide meshes in different configurations(square,triangular and hexagonal meshes)are designed to realize optical signal interleaving with arbitrary duty *** digital signal processing(DSP)approach offers an effective pathway for the establishment of a general design platform for the software-defined programmable photonic integrated *** use of well-developed DSP techniques and algorithms establishes a link between optical and electrical signals and makes it convenient to realize the computer-aided design of optics–electronics hybrid systems.

关键词： photonic integrated circuit digital signal processing z-transform

Description and reconstruction of one-dimensional photonic crystal by digital signal processing theory

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Chinese Physics B 2014年第10期23卷 200-204页

作者：张娟付文鹏张荣军王阳 Key Laboratory of Specialty Fiber Optics and Optical Access Networks School of Communication and Information Engineering Shanghai University Key Laboratory of High Power Laser Materials Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences

A method of describing one-dimensional photonic crystals （1DPCs） based on z-domain digital signal processing theory is presented. The analytical expression of the target band gap spectrum in the digital domain is obtained by the autocorrelation of its impulse response. The feasibility of this method is verified by reconstructing two simple 1DPC structures with a target photonic band gap obtained by the traditional transfer matrix method. This method provides an effective approach to function-guided designs of interference-based band gap structures for photonic applications.

关键词： one-dimensional photonic crystal digital signal processing z-transform

Numerical Computations of Nonlocal Schrodinger Equations on the Real Line

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Communications on Applied Mathematics and Computation 2020年第2期2卷 241-260页

作者： Yonggui Yan Jiwei zhang Chunxiong zheng Beijing Computational Science Research Center Beijing 100093China School of Mathematics and Statistics and Hubei Key Laboratory of Computational ScienceWuhan UniversityWuhan 430072China Department of Mathematical Sciences Tsinghua UniversityBeijing 100084China College of Mathematics and Systems Science Xinjiang UniversityUnimqi 830046China

The numerical computation of nonlocal Schrödinger equations (SEs) on the whole real axis is considered. Based on the artifcial boundary method, we frst derive the exact artifcial nonrefecting boundary conditions. For the numerical implementation, we employ the quadrature scheme proposed in Tian and Du (SIAM J Numer Anal 51:3458-3482, 2013) to discretize the nonlocal operator, and apply the z-transform to the discrete nonlocal system in an exterior domain, and derive an exact solution expression for the discrete system. This solution expression is referred to our exact nonrefecting boundary condition and leads us to reformulate the original infnite discrete system into an equivalent fnite discrete system. Meanwhile, the trapezoidal quadrature rule is introduced to discretize the contour integral involved in exact boundary conditions. Numerical examples are fnally provided to demonstrate the efectiveness of our approach.

关键词： Nonrefecting boundary conditions Artifcial boundary method Nonlocal Schrödinger equation z-transform Nonlocal models

The Global Behavior of Finite Difference-Spatial Spectral Collocation Methods for a Partial Integro-differential Equation with a Weakly Singular Kernel

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Numerical Mathematics(Theory,Methods and Applications) 2013年第3期6卷 556-570页

作者： Jie Tang Da Xu College of Mathematics and Computer Science Hunan Normal UniversityChangsha 410081HunanP.R.China College of Science Hunan University of TechnologyZhuzhou 412008HunanP.R.China

The z-transform is introduced to analyze a full discretization method fora partial integro-differential equation (PIDE) with a weakly singular kernel. In thismethod, spectral collocation is used for the spatial discretization, and, for the time stepping, the finite difference method combined with the convolution quadrature rule isconsidered. The global stability and convergence properties of complete discretizationare derived and numerical experiments are reported.

关键词： Partial integro-differential equation weakly singular kernel spectral collocation methods z-transform convolution quadrature

Analysis of stability and bullwhip effect in production-inventory systems

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Journal of Southeast University(English Edition) 2011年第1期27卷 101-106页

作者：张冲王海燕东南大学经济管理学院南京211189

To discuss the relationship between stability and bullwhip effect in the supply chain system,a basic model in a production-inventory control system is developed using difference equations.z-transform techniques are applied to investigate the production ordering and inventory *** the two operational regimes of sufficient inventory coverage and insufficient inventory coverage,the scope of decision parameters which make the system stable or instable is *** two operational regimes and the actual system,production release rates,stability/instability and bullwhip effect in the stable region and instable region are examined based on different demand functions,and then the numerical simulation results are *** results show that reasonable choices of fractional adjustment of inventory and supply line can make the system stable and decrease bullwhip *** is summarized that the piecewise linearization based on the stability analysis approach is a valid approximation to the analysis of production-inventory ordering systems with *** interesting results are obtained and they have important implications for improving inventory and order decisions in supply chain systems.

关键词： production-inventory systems stability analysis bullwhip effect z-transform

Frequency Domain Convolution of Rational Transfer Functions

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Journal of Applied Mathematics and Physics 2022年第6期10卷 2117-2129页

作者： Ishan Kar Prospect High School Saratoga USA

The convolution of two rational transfer functions is also rational, but a formula for the convolution has never been derived. This paper introduces a formula for the convolution of two rational functions in the frequency domain by two new methods. The first method involves a partial fraction expansion of the rational transfer functions where the problem gets reduced to the sum of the convolution of the partial fractions of the two functions, each of which can be solved by a new formula. Since the calculation of the roots of a high-order polynomial can be very time-consuming, we also demonstrate new methods for performing the convolution without calculating these roots or undergoing partial fraction expansion. The convolution of two rational Laplace transform denominators can be calculated using their resultant, while that of the two rational z-transform transfer functions can be found using Newton’s identities. The numerator can be easily found by multiplying the numerator with the initial values of the power series of the result.

关键词： z-transform Laplace transform Frequency Domain Convolution

On Impulse Switching Functions of Inverters as an Orthogonal System

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Journal of Mathematics and System Science 2014年第12期4卷 743-749页

作者： B. Dobrucky M. Pokomy M. Benova Faculty of Electrical Engineering University of Zilina 8215 Univerzitna 01026 Zilina Slovak Republic

The paper deals with impulse switching function which are used as exciting functions of one- and multidimensional state-space models of power electronic converters. Obviously, these functions are harmonic but using power converters they can be strongly non-harmonic, sometimes piecewise constants with zero spaces between them. Then, one deals with power series of time pulses. The impulse switching functions which are orthogonal ones can be derived from these series. The new impulse switching functions are created using z-transform, inverse z-transform and numerical series/sequences. The impulse switching functions created this way can be used for both steady- and transient state investigation of converters.

关键词： Power converter impulse switching function z-transform inverse z-transform modelling and simulation steady stateoperation