A generalized algorithm for the capacitance extraction of 3D VLSIinterconnects

In this paper, a generalized algorithm based upon the nonoverlapping domain decomposition method (NDDM) is presented for the capacitance extraction of three-dimensional (3-D) VLSI interconnects. The subdomains with conductors are analyzed by the finite-difference method, while the subdomains with pure dielectric layers are analyzed with the eigenmode expansion technique. The central processing unit time and memory size used by the NDDM are unrelated to the thickness of pure dielectric layers. NDDM's computing time grows as O(n) if the number of domain iterations is bounded. Also, benchmarks show that it is approximately 15 times less than those used by Ansoft's Maxwell SpiceLink. In addition, only a two-dimensional mesh is needed to analyze 3-D structures. This greatly reduces the algorithm complexity and makes it easy and straightforward to interface with layout automation software     

Double-image Green's function method for 3-D capacitance and conductance extraction of on-chip transmission lines

A new double-image Green's function approach is developed to compute the frequency-dependent capacitance and conductance for three-dimensional multilayered on-chip transmission lines on silicon substrate. The ε-algorithm of the Pade approximation is adopted to reduce the time for establishing the coefficient matrix. The parameters gained from this new approach are shown to be in good agreement with the data obtained by the total charge Green's function method.     

3-D vector radix algorithm for the 3-D new Mersenne numbertransform

Three-dimensional convolutions and correlations are used for three-dimensional image-processing applications. Their calculation involves extensive computation, which makes the use of fast transforms very advantageous. As the number of arithmetic operations is very large, the accumulation of rounding or truncation errors arising in the use of the fast Fourier and Hartley transforms tends to increase. Number theoretic transforms are calculated modulo an integer and hence they are not subject to these errors. Previously, a one-dimensional transform called the new Mersenne number transform (NMNT) was introduced and applied successfully to the calculation of 1-D convolutions/correlations. Unlike other Mersenne number transforms, the NMNT can handle long data sequences and has fast algorithms. In the paper, the 1-D definitions are first extended to the 3-D case in detail for use in 3-D image processing applications. The concept and derivation of the 3-D vector radix algorithm is then introduced for the fast calculation of the 3-D NMNT. The proposed algorithm is found to offer substantial savings over the row-column approach in terms of arithmetic operations. Examples are given showing the validity of both transform and algorithm     

Fast algorithm for the 3-D DCT-II

Recently, many applications for three-dimensional (3-D) image and video compression have been proposed using 3-D discrete cosine transforms (3-D DCTs). Among different types of DCTs, the type-II DCT (DCT-II) is the most used. In order to use the 3-D DCTs in practical applications, fast 3-D algorithms are essential. Therefore, in this paper, the 3-D vector-radix decimation-in-frequency (3-D VR DIF) algorithm that calculates the 3-D DCT-II directly is introduced. The mathematical analysis and the implementation of the developed algorithm are presented, showing that this algorithm possesses a regular structure, can be implemented in-place for efficient use of memory, and is faster than the conventional row-column-frame (RCF) approach. Furthermore, an application of 3-D video compression-based 3-D DCT-II is implemented using the 3-D new algorithm. This has led to a substantial speed improvement for 3-D DCT-II-based compression systems and proved the validity of the developed algorithm.     

三维寄生电容边界元计算的半解析积分方法

在VLSI三维多介质互连寄生电容的边界元法计算中,利用互连结构特点,本文提出一种半解析积分方法,它应用原函数方法将二维面积分转化为一维线积分,再用一维高斯积分求出积分值.与二维高斯积分相比,速度更快、精度更高,并改善了解的精度.     

一种高分辨率3维图像的自适应降噪算法

为了获得高保真3维图像,采用了一种针对高分辨率3维图像的自适应均值降噪算法。首先使用一种由激光器、高分辨率3维相机、直线电机和计算机等设备组成的线激光高精度3维测量实验系统对自然纹理皮革进行测量。然后针对系统测量所得的高分辨率3维自然纹理图像(每英寸点数大于1000),进行了理论分析和实验验证,取得了降噪后的高保真3维图像数据,并与传统的均值滤波、小波变换滤波的降噪效果进行对比。结果表明,该算法能自动选取最优的降噪窗口,有效地去除3维图像的噪声信息,并保留高分辨率图像丰富的边缘、细节信息,最终得到高保真的高分辨率3维自然纹理图像。该实验结果对于高分辨率图像的降噪问题是十分有帮助的。     

3-D face structure extraction and recognition from images using 3-D morphing and distance mapping

We describe a novel approach for creating a three-dimensional (3-D) face structure from multiple image views of a human face taken at a priori unknown poses by appropriately morphing a generic 3-D face. A cubic explicit polynomial in 3-D is used to morph a generic face into the specific face structure. The 3-D face structure allows for accurate pose estimation as well as the synthesis of virtual images to be matched with a test image for face identification. The estimation of a 3-D person's face and pose estimation is achieved through the use of a distance map metric. This distance map residual error (geometric-based face classifier) and the image intensity residual error are fused in identifying a person in the database from one or more arbitrary image view(s). Experimental results are shown on simulated data in the presence of noise, as well as for images of real faces, and promising results are obtained.     

Dead-reckoning sensor system and tracking algorithm for 3-D pipeline mapping

A dead-reckoning sensor system and a tracking algorithm for 3-D pipeline mapping are proposed for a tap water pipeline for which the diameter is small and the inner surface is rough due to pipe scales. The goals of this study are to overcome the performance limitations of small and low-grade sensors by combining various sensors with complementary functions and achieve robustness against a severe environment. A dead-reckoning sensor system consists of a small, low-cost micro electromechanical system inertial measurement unit (MEMS IMU) and an optical navigation sensor (used in laser mice). A tracking algorithm consists of a multi-rate extended Kalman filter (EKF) to fuse redundant and complementary data from the MEMS IMU and the optical navigation sensor and a geometry compensation method to reduce position estimation error using the end point of the pipeline. Two sets of experimental data have been obtained by driving a radio-controlled car equipped with the sensor system in a 3-D pipeline and on asphalt pavement. Our study can be used to estimate the path of a 3-D pipeline or mobile robots.     

An algorithm for encoding and decoding the 3-D Hilbert order

Spatial ordering is a transformation relating an n-dimensional voxel to a set of natural numbers. Interest in the Hilbert order (H-order) has been high because of its desirable performance when applied to image processing. In this correspondence, an encoding/decoding algorithm for the three-dimensional (3-D) Hilbert order is presented.     

An improvement to MBASIC algorithm for 3-D motion and depthestimation

In model-based coding of facial images, the accuracy of motion and depth parameter estimates strongly affects the coding efficiency. MBASIC (model-based analysis-synthesis image coding) is a simple and effective iterative algorithm recently proposed by Aizawa et el. (see Signal Processing: Image Communication, no.1, p.139-52, 1989) for 3-D motion and depth estimation when the initial depth estimates are relatively accurate. In this correspondence, we analyze its performance in the presence of errors in the initial depth estimates and propose a modification to MBASIC algorithm that significantly improves its robustness to random errors with only a small increase in the computational load.     

合成孔径激光雷达下视三维成像构型及算法

传统激光三维成像均采用实孔径成像技术,其分辨率会随着作用距离的变远而降低。相比于实孔径成像,合成孔径成像的一个显著优势是沿航向的分辨率不随作用距离的变化而变化。基于合成孔径技术提出一种合成孔径激光三维成像雷达的工作模型。该系统采用激光泛光发射模式和多波束相干接收,首先,在高度向,采用大时宽带宽的线性调频信号,并利用解线频调技术实现高分辨率;其次,沿航向利用合成孔径技术频域压缩算法实现高分辨率,其中考虑到激光调频信号的长扫频周期,对于平台连续运动引入的多普勒平移项进行了补偿;在跨航向通过实孔径阵列实现高分辨率。最后,通过仿真实验验证了该系统的有效性。     

Analysis of the subthreshold slope and the linear transconductancetechniques for the extraction of the capacitance coupling coefficientsof floating-gate devices

A critical investigation of the relationship between the floating gate and the accessible terminal voltages reveals that the gate coupling coefficient is overestimated by the traditional expressions obtained from the approximate analysis of the subthreshold slope and the linear transconductance techniques. The investigation further indicates that the subthreshold slope technique is preferred, because the corrections can be easily estimated using the results of auxiliary measurements involving the source and drain coupling coefficients     

Dominant pattern extraction from 3-D kinematic data

A new method for the extraction of a repeating pattern in cyclic biomechanical data is proposed-singular value decomposition pattern analysis (SVDPA). This method is based on the recent work of Kanjilal and Palit (1994, 1995) and can be applied to both contiguous and repeated trials without being constrained to be strictly periodic. SVDPA is a data-driven approach that does not use a preselected set of basis functions; but instead utilizes a data matrix with a special structure to identify repeating patterns. Several important features of SVDPA are described including its close relationship to the Kahunen-Loeve transform. The dominant pattern is defined as the average energy component (AEC). The AEC is obtained from the SVD of the data matrix and is equivalent to the optimal [maximal signal-to-noise ratio (SNR)] ensemble average pattern. The degree of periodicity and SNR for the AEC are defined explicitly from the singular values of the data matrix. The authors illustrate the usefulness of SVDPA for dominant pattern extraction by applying it to the quasiperiodic three-dimensional trajectory of a marker attached to the trunk during treadmill locomotion. The AEC obtained for the normalized trajectory and error estimates at each point suggests that SVDPA could be a useful tool for the extraction of the fine details from cyclic biomechanical data     

A 3-D generalized direct PWM algorithm for multilevel converters

A three-dimensional (3-D) generalized direct pulse width modulation (PWM) algorithm is proposed for multilevel converters in a three-phase, four-wire system. It is proved to be equivalent to the newly proposed generalized 3-D space vector modulation (SVM). However, the direct PWM greatly simplifies the calculation process and is much easier to implement in digital controllers. The direct PWM can be used in all applications needing a 3-D control vector, such as active filters, uninterruptible power supplies, etc. Simulation and experimental results are given to show the validity of the proposed control strategy.     

Electromagnetic 3-D model for active linear devices: application to pHEMTs in the linear regime

In this paper, we describe a three-dimensional (3D) electromagnetic (EM) approach to the modeling of active devices in their linear regime. The technique basically relies on the self-consistent introduction of distributed controlled current sources in the 3D EM simulation of passive components. The approach is validated by comparing measured and calculated results for a pseudomorphic high electron-mobility transistor in the millimeter-wave range. However, it may also be applied to a larger class of field-effect transistors, including MESFETs.     

2-D system theory based iterative learning control for linear continuous systems with time delays

This paper presents two-dimensional (2-D) system theory based iterative learning control (ILC) methods for linear continuous multivariable systems with time delays in state or with time delays in input. Necessary and sufficient conditions are given for convergence of the proposed ILC rules. In this paper, we demonstrate that the 2-D linear continuous-discrete Roesser's model can be applied to describe the ILC process of linear continuous time-delay systems. Three numerical examples are used to illustrate the effectiveness of the proposed ILC methods.     

Frequency dispersive materials for 3-D hybrid solvers in time domain

The recursive convolution method to treat linear dispersive materials in the finite difference time domain (FDTD) is here generalized to an explicit finite volume solver and an implicit finite element solver. Both solvers are interfaced to FDTD resulting in two hybrid solvers. The stability of the solvers is analyzed and the accuracy is demonstrated in several scattering cases, where a plane wave illuminates a sphere with complex permittivity. Excellent agreement with the analytical Mie series solution is obtained for materials of Debye and Lorentz type as well as for a material consisting of two Lorentz poles.     

Principal curves for lumen center extraction and flow channel width estimation in 3-D arterial networks: theory, algorithm, and validation

We present an energy-minimization-based framework for locating the centerline and estimating the width of tubelike objects from their structural network with a nonparametric model. The nonparametric representation promotes simple modeling of nested branches and n -way furcations, i.e., structures that abound in an arterial network, e.g., a cerebrovascular circulation. Our method is capable of extracting the entire vascular tree from an angiogram in a single execution with a proper initialization. A succinct initial model from the user with arterial network inlets, outlets, and branching points is sufficient for complex vasculature. The novel method is based upon the theory of principal curves. In this paper, theoretical extension to grayscale angiography is discussed, and an algorithm to find an arterial network as principal curves is also described. Quantitative validation on a number of simulated data sets, synthetic volumes of 19 BrainWeb vascular models, and 32 Rotterdam Coronary Artery volumes was conducted. We compared the algorithm to a state-of-the-art method and further tested it on two clinical data sets. Our algorithmic outputs-lumen centers and flow channel widths-are important to various medical and clinical applications, e.g., vasculature segmentation, registration and visualization, virtual angioscopy, and vascular atlas formation and population study.     

求解三维麦克斯韦方程的时域无网格算法研究

发展了用于求解三维麦克斯韦方程的时域无网格算法.算法基于生成的无网格点云,通过泰勒级数展开结合加权最小二乘逼近计算点云中心点上的空间导数,并构造近似黎曼解处理空间离散涉及的通量运算;空间离散后的半离散方程则采用四步Runge-Kutta格式推进求解.结合求解三维麦克斯韦方程,给出了时域无网格算法的具体实施过程,并基于发展的算法,成功地模拟出金属球、立方体及进气道模型等三维散射目标的电磁散射场,获得的雷达散射截面能与理论解、矩量法或精确控制法等结果吻合.     

The 3-D multidomain pseudospectral time-domain algorithm for inhomogeneous conductive media

A three-dimensional (3-D) multidomain pseudospectral time-domain (PSTD) method with a strongly well-posed perfectly matched layer (PML) is developed as an accurate and flexible tool for the simulation of electromagnetic wave propagation and scattering in inhomogeneous and conductive media. This approach allows for an accurate treatment of curved geometries by multidomain decomposition and curvilinear coordinate transformation. Numerical experiments show the results agree excellently with analytical solutions and results of other well-known algorithms, and demonstrate a remarkable improvement in accuracy and efficiency over the FDTD method. The 3-D multidomain PSTD algorithm is then applied to calculate radar cross sections (RCS).