几何基元的提取方法

基元提取在基于模型的计算机视觉中起着重要的作用。基元抽取问题可以归结为优化问题,即寻找代价函数的全局最小值。利用统计方法对最小子集进行随机抽样,大大减少了对最小子集的评价。同时引入了参数向量列表,并提出了一种新的代价函数,用于对基元的参数向量进行评价,使计算量减少、抽取精度提高。该方法可以用于多个基元的提取。分析实验结果表明,该方法能快速、准确地提取集合基元。     

Simulation and Modeling-implementing GaAs device models with SPICE

A method for evaluating the accuracy of a device model and its tendency toward convergence problems before implementing it as a SPICE primitive is presented. Two different GaAs MESFET models suitable for analyzing nonlinear analog and microwave circuits are implemented using generic SPICE primitives. It is shown that no modification to the SPICE program is required. Controlled sources are extensively used in implementing the models using this method     

Modeling and comparing CMOS implementations of the C-element

Various applications have demonstrated that asynchronous circuits have great potential for energy-efficient and high-performance design. One of the primitives used in asynchronous control circuits is the C-element. Analytical delay and energy models are presented and applied to the most popular complementary metal-oxide-semiconductor (CMOS) implementations of the C-element. Optimization of these implementations are discussed. The implementations are also compared using simulations. The simulation results are in good agreement with the analytical predictions     

Simulated polarimetric signatures of primitive geometrical shapes

Polarimetric signatures of two primitives shapes (dihedral and edge) are simulated using high-frequency electromagnetic scattering methods. Signatures are predicted for a variety of orientations of the shapes. Polarimetric responses are analyzed using a polarization scattering matrix decomposition developed by Cameron and Leung (1990, 1992). It is shown that symmetric scatterer responses can be represented as points contained in the unit disc of the complex plane. The simulation shows that the polarimetric responses of the primitive shapes are remarkably stable as the shapes are rotated about various axes     

一种图象中基元检测的新方法

在模式识别和机器视觉中,常常需要进行图象中的基元检测。本文以圆的检测为例提出了一种利用遗传算法进行基元检测的方法。实验结果表明,本文方法与通常的模板匹配和Hough变换相比速度大大提高。     

Colour image retrieval based on primitives of colour moments

A colour image retrieval method based on the primitives of colour moments is proposed. First, an image is divided into several blocks. Then, the colour moments of all blocks are extracted and clustered into several classes. The mean moments of each class are considered as a primitive of the image. All primitives are used as features. Since two different images may have different numbers of features, a new similarity measure is then proposed. To demonstrate the effectiveness of the proposed method, two test databases from Corel are used to compare the performances of the proposed method with other existing ones. The experimental results show that the proposed method is usually better than the others. Furthermore, since for a few special types of images, other methods may have better results occasionally, a relevance feedback algorithm is also provided to automatically determine the best method according to the user's response.     

Image coding with ridge and valley primitives

A high-compression image coding scheme is presented, based on thread-like “Ridge” and “Valley” primitives. The use of these primitives is motivated by their success in economically representing image structure. The original image is sampled along the primitives, using a fractal yardstick method to determine sample spacing. The primitives themselves are compressed using vector coding and chain coding. Reconstruction at the receiver is a scattered data interpolation problem, solved here using C⁰ natural neighbor interpolation. Results are presented showing data rates between 0.1 and 0.4 b/pixel, the degradations are discussed, and prospects for improvement outlined     

Minimal Complete Primitives for Secure Multi-Party Computation

The study of minimal cryptographic primitives needed to implement secure computation among two or more players is a fundamental question in cryptography. The issue of complete primitives for the case of two players has been thoroughly studied. However, in the multi-party setting, when there are n > 2 players and t of them are corrupted, the question of what are the simplest complete primitives remained open for t n/3. (A primitive is called complete if any computation can be carried out by the players having access only to the primitive and local computation.) In this paper we consider this question, and introduce complete primitives of minimal cardinality for secure multi-party computation. The cardinality issue (number of players accessing the primitive) is essential in settings where primitives are implemented by some other means, and the simpler the primitive the easier it is to realize. We show that our primitives are complete and of minimal cardinality possible for most cases.     

SPICE macro model for the simulation of zener diodeI-V characteristics

The problems encountered when using the existing SPICE diode model to represent the I-V characteristics of a Zener diode in the reverse region are examined. A Zener diode macro model that has accurate I-V simulation characteristics and can be easily constructed using SPICE-provided primitives is presented. The static I-V characteristics and temperature response of the diode are reviewed. The performance of the model is discussed, and its main enhancements as compared to the SPICE model are identified     

典型几何基元的高频散射建模方法梳理

高分辨率SAR图像中蕴含目标与环境丰富的信息,但复杂的电磁散射机制使其难以直观解译,这一直是SAR图像解译的重要研究课题.该文简单梳理了典型几何基元的高频散射建模方法,以面散射、线散射和点散射为线索简要回顾了若干高频散射机制的研究发展过程,并给出几种典型几何基元的散射机制表达式及部分仿真结果,分析了典型散射机制表征面临...     

实时图像处理并行操作系统的微内核设计和实现

本文主要设计和实现了运行在数字信号处理阵列上支持中高层图像处理的实时图像处理并行操作系统（ＲＴＩＰＰＯＳ）微内核，该内核提供了任务分解模型，并发进程管理，支持局部消息传递，同步，设计了快速共享消息传递方式和它辅助性能，内核原语支持ＰＯＳＩＸ系统调用的Ｃ语言接口和抽象级的用户封装，有行为的高效性和预测性，本文是对ＲＴＩＰＰＯＳ微内核设计的综述。     

Application modeling for performance evaluation on event-triggered wireless sensor networks

This paper presents an approach for event-triggered wireless sensor network (WSN) application modeling, aiming to evaluate the performance of WSN configurations with regards to metrics that are meaningful to specific application domains and respective end-users. It combines application, environment-generated workload and computing/communication infrastructure within a high-level modeling simulation framework, and includes modeling primitives to represent different kind of events based on different probabilities distributions. Such primitives help end-users to characterize their application workload to capture realistic scenarios. This characterization allows the performance evaluation of specific WSN configurations, including dynamic management techniques as load balancing. Extensive experimental work shows that the proposed approach is effective in verifying whether a given WSN configuration can fulfill non-functional application requirements, such as identifying the application behavior that can lead a WSN to a break point after which it cannot further maintain these requirements. Furthermore, through these experiments, we discuss the impact of different distribution probabilities to model temporal and spatial aspects of the workload on WSNs performance, considering the adoption of dynamic and decentralized load balancing approaches.     

High-performance expert system-DBMS interface for networkmanagement and control

The field of network management in modern telecommunications networks is discussed along with the need for database and expert systems techniques in this field. It is pointed out that one of the requirements is the capability of inferencing with a very large volume of factual information. A framework is presented for optimization in coupling an expert system and a database management system (DBMS) in such a way to satisfy this requirement. A loose coupling strategy is adopted as a practical solution allowing utilization of an existing DBMS. Specifically, techniques for normalizing the logic query, implementation primitives, and the set of access strategies as mappings between the normalized primitives and implementation primitives is presented. The techniques are discussed in the context of an expert system shell, the SOL Inference Engine for Network Applications (SIENA)     

Similarity measure for superquadrics

Superquadrics with parametric deformations are suitable models for use as solid primitives for describing a complicated 3-D object. Some different methods for the recovery of superquadric primitives from range data have been proposed, but there is still no effective similarity measure for the matching task between two superquadrics in a 3-D object recognition system. The authors propose a similarity measure to evaluate the degree of shape similarity between two superquadric-based objects. This similarity measure is defined as the volume of regions bounded by the surfaces of two 3-D objects. The proposed measure has been proved to be a metric. The metric value is computed by the Monte Carlo integration method. The experimental results illustrate that the proposed similarity measure is effective in matching a recovered superquadric with a set of superquadrics in the model database     

Computer-aided programming for message-passing systems: problemsand solutions

As the number of processors and the complexity of problems to be solved increase, programming multiprocessing systems becomes more difficult and error prone. Program development tools are necessary since programmers are not able to develop complex parallel programs efficiently. Parallel models of computation, parallelization problems, and tools for computer-aided programming (CAP) are discussed. As an example, a CAP tool that performs scheduling and inserts communication primitives automatically is described. It also generates the performance estimates and other program quality measures to help programmers in improving their algorithms and programs     

Application of line-edge profile simulation to thin-film deposition processes

A computer simulation program based on a segment-motion model has been developed to investigate thin-film-deposition processes. This simulation program is used to study the physical phenomena in the thin-film-deposition process as well as the effects of different tooling configurations and operating conditions. The simulated results are compared with experimental results obtained from an electron-gun evaporator with planetary tooling and from a planarizing sputtered quartz system to verify the accuracy of the simulation and to illustrate imporant phenomena during the deposition process. The simulation program is also used in exploratory studies to find the optimum source angle for step coverage in a typical planetary evaporator. The step coverage is found to change only slightly for wafers at different locations on the planet, but can change significantly depending on the pattern orientation on the wafers if the wafer rotation is not independent of the planet rotation. A study of the sputtered quartz planarization process shows that the growth of different topological features can be accurately predicted from the change in deposition and etching rate as a function of the angle of incidence. In particular, the increased deposition near a conductor edge is attributed to the propagation of a growth front from the sidewall boundary conditions.     

Application of Line-Edge Profile Simulation to Thin-Film Deposition Processes

A computer simulation program based on a segment-motion model has been developed to investigate thin-film-deposition processes. This simulation program is used to study the physical phenomena in the thin-film-deposition process as well as the effects of different tooling configurations and operating conditions. The simulated results are compared with experimental results obtained from an electron-gun evaporator with planetary tooling and from a planarizing sputtered quartz system to verify the accuracy of the simulation and to illustrate important phenomena during the deposition process. The simulation program is also used in exploratory studies to find the optimum source angle for step coverage in a typical planetary evaporator. The step coverage is found to change only slightly for wafers at different locations on the planet, but can change significantly depending on the pattern orientation on the wafers if the wafer rotation is not independent of the planet rotation. A study of the sputtered quartz planarization process shows that the growth of different topological features can be accurately predicted from the change in deposition and etching rate as a function of the angle of incidence. In particular, the increased deposition near a conductor edge is attributed to the propagation of a growth front from the sidewall boundary conditions.     

A Tool for Structured Functional Simulation

BLOSIM is a general purpose time-driven (as opposed to event-driven) simulation language. It is written in C language, and is intended to provide a highly structured environment for simulations, thereby making practical the accumulation of libraries of simulation routines which can be reused and making multiprogrammer simulation efforts more practical. It is written with the philosophy of not including any simulation primitives within the language itself, but rather complete generality is maintained by having the user provide these as C routines (either coded from scratch or from a user-provided library). It includes as features a hierarchical specification of blocks, interconnection of blocks by first-in first-out buffers, the passing of parameters to blocks, multiple instances of blocks, and automatic scheduling of the order of block execution. It has been used for the multiprogrammer simulation of data transmission and speech processing systems, in both academic and industrial environments, with good results.     

NoC_MPSim:基于片上网络通信架构多核仿真平台

实现了一个用于探索基于片上网络通信架构多核系统设计空间的可配置仿真平台--NoC_MPSim.该平台包含处理器工具链、平台自动化配置脚本以及一个包含处理器、网络适配器以及多种路由器的RTL模型库,可根据用户输入的系统配置信息自动生成周期精确的多核仿真系统.针对片上网络通信架构的特征,定义了基于该通信架构的多核系统的高层次通信抽象模型,并借鉴并行机中的消息传递机制,提出了一种可有效隐藏网络乱序的并行编程模型及其通信原语,并完成其所需要的软\硬件建模.应用提出的编程模型,实现了MUSIC算法基于四核仿真系统的分布式并行计算,并经实验得到该并行MUSIC算法在该系统中加速比可达2.6.