检索结果-内蒙古大学图书馆

Image-adaptive vector quantization in an entropy-constrained framework

IEEE TRANSACTIONS ON IMAGE PROCESSING 1997年第3期6卷 441-450页

作者： Lightstone, M Mitra, SK UNIV CALIF SANTA BARBARA DEPT ELECT & COMP ENGNCTR INFORMAT PROC RESSANTA BARBARACA 93106

An adaptive vector quantization (VQ) scheme with codebook transmission is derived for the variable-rate source coding of image data using an entropy-constrained Lagrangian framework, Starting from an arbitrary initial codebook C-I available to both the encoder and decoder, the proposed algorithm iteratively generates an improved operational codebook C-O that is well adapted to the statistics of a particular image or subimage. Unlike other approaches, the rate-distortion trade-offs associated with the transmission of updated code vectors to the decoder are explicitly considered in the design, In all cases, the algorithm guarantees that the operational codebook C-O will have rate-distortion performance (including all side-information) better than or equal to that of any initial codebook C-I. When coding the Barbara image, improvement at all rates is demonstrated with observed gains of up to 3 dB in peak signal-to-noise ratio (PSNR). Whereas in general the algorithm is multipass in nature, encoding complexity can be mitigated without an exorbitant rate-distortion penalty by restricting the total number of iterations. Experiments are provided that demonstrate substantial rate-distortion improvement can be achieved with just a single pass of the algorithm.

关键词： Rate distortion subimage decoders image data algorithms ENCODER generalized algorithm Vector quantization Peak signal-to-noise ratio codebook

来源：评论

学校读者我要写书评

暂无评论

Simple heuristic algorithm for profile reduction of arbitrary sparse matrix

引用

APPLIED MATHEMATICS AND COMPUTATION 2005年第2期168卷 848-857页

作者： Ossipov, P Russian Acad Sci Inst Engn Mech Kazan 420111 Russia

The simple universal algorithm for profile reduction of arbitrary sparse matrix is described. It is shown that even for intelligent strategy of generation and numbering of internal nodes suggested algorithm can reduce profile by factor 2-3. This method can be modified easily for general task of matrix transformation to arbitrary desirable form. To minimize the profile further the method can be embedded in depth-first search of artificial intelligence. (c) 2004 Elsevier Inc. All rights reserved.

关键词： Heuristic algorithms Arbitrary generalized algorithm Sparse matrix Depth--first search

来源：评论

学校读者我要写书评

暂无评论

Universal algorithm of Adaptive Optimal-Invariant Signal Filtering

引用

IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE 2011年第4期26卷 31-32页

作者： Ivanov, Yu. P. State Univ Aerosp Instrumentat St Petersburg 190000 Russia

The algorithm of optimal-invariant adaptive signal filtering for models of interferences of measurement in the form of Markovian processes of k(th) order by the example of a complex system with the filter of a different signal is offered. The demanded level of a priori determinancy concerning the noise of measurement includes knowledge of approximate duration of intervals of a quasi-stationarity noise of measurement, a sort of linear model of measurement, a variance of high-frequency noise, and the presence of a mutual non-correlated signal and noise. The algorithm, in the course of operation, besides optimal filtering of signals, evaluates the quality of the handling of signals and defines adapting time. In the presence of information on correlative functions, the noise of measurement by the algorithm ensures optimally-invariant filtering of Kalman signals without the necessity of a solution of the Rikkati equation.

关键词： optimal filters Complex systems linear models model measurement signals generalized algorithm high frequency noise signal filtering Self tuning

来源：评论

学校读者我要写书评

暂无评论

Sigma-Point Kalman Filtering for Spacecraft Attitude and Rate Estimation using Magnetometer Measurements

引用

IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2011年第2期47卷 1401-1415页

作者： Abdelrahman, Mohammad Park, Sang-Young Yonsei Univ Dept Astron Astrodynam & Control Lab Seoul 120749 South Korea

A generalized algorithm for spacecraft three-axis attitude and rate estimation is presented. The filter concept presented here is quite general and applicable to a wide range of sensor systems. The structure of the filter is built using spacecraft nonlinear dynamics in the presence of momentum exchange devices. Then quaternion kinematics are augmented with spacecraft dynamics to represent the filter process dynamics. Magnetometer measurements and their corresponding time derivatives are utilized to represent the filter measurement model. The filter is designed to suit spacecraft in low-Earth orbits, so the aerodynamic drag in addition to spacecraft magnetic residuals are included as disturbance torques to the process dynamics. To test the filter EgyptSat-1 is used as a real test case where a magnetometer and fiber-optic gyros are used for attitude and rate determination. A Monte-Carlo simulation is then applied to study the performance of the proposed filter with initial attitude and angular velocity sampled from a uniform distribution, each axis respectively. The filter shows the capability of estimating the attitude within 5 deg and rate on the order of 0.03 deg/s in each axis.

关键词： aerodynamic drag ANGULAR VELOCITY Attitude Spacecraft CASING INSPECTION Spacecraft dynamics generalized algorithm Filters magnetometers Process dynamics Sensor systems

来源：评论

学校读者我要写书评

暂无评论

Incremental construction of minimal acyclic finite-state automata

引用

COMPUTATIONAL LINGUISTICS 2000年第1期26卷 3-16页

作者： Daciuk, J Mihov, S Watson, BW Watson, RE Gdansk Univ Technol Dept Appl Informat PL-80952 Gdansk Poland Bulgarian Acad Sci Linguist Modelling Lab LPDP BG-1040 Sofia Bulgaria Univ Pretoria Dept Comp Sci ZA-0002 Pretoria South Africa

In this paper, we describe a new method for constructing minimal, deterministic, acyclic finite-state automata from a set of strings. Traditional methods consist of two phases: the first to construct a trie, the second one to minimize it. Our approach is to construct a minimal automaton in a single phase by adding new strings one by one and minimizing the resulting automaton on-the-fly. We present a general algorithm as well as a specialization that relies upon the lexicographical ordering oft he input strings. Our method is fast and significantly lowers memory requirements in comparison to other methods.

关键词： Automata TWO-PHASE Specialization Minimal single phase Fasting new methods generalized algorithm input string Robot memory requirements Cosmic strings

来源：评论

学校读者我要写书评

暂无评论

An efficient algorithm to compute the candidate keys of a relational database schema

引用

COMPUTER JOURNAL 1996年第2期39卷 124-132页

作者： Saiedian, H Spencer, T UNIV NEBRASKA DEPT COMP SCI OMAHA NE 68182 USA

We provide an efficient algorithm for computing the candidate keys of a relational database scheme. The algorithm exploits the 'arrangement' of attributes in the functional dependencies to determine which attributes are essential and useful for determining the keys and which attributes should not be considered. A more generalized algorithm using attribute graphs is then provided which allows a uniform and simplified solution to find all possible keys of a relational database schema when the attribute graph of Functional Dependencies (FDs) is not strongly connected.

关键词： relational database schema efficient algorithm algorithms generalized algorithm Database database schema Lexical permutation sorting Locks

来源：评论

学校读者我要写书评

暂无评论

Ultrasound Time-Reversal MUSIC Imaging With Diffraction and Attenuation Compensation

引用

IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL 2012年第10期59卷 2186-2200页

作者： Labyed, Yassin Huang, Lianjie Los Alamos Natl Lab Los Alamos NM USA

Time-reversal imaging with multiple signal classification (TR-MUSIC) is an algorithm for imaging point-like scatterers embedded in a homogeneous and non-attenuative medium. We generalize this algorithm to account for the attenuation in the medium and the diffraction effects caused by the finite size of the transducer elements. The generalized algorithm yields higher-resolution images than those obtained with the original TR-MUSIC algorithm. We evaluate the axial and lateral resolutions of the images obtained with the generalized algorithm when noise corrupts the recorded signals and show that the axial resolution is degraded more than the lateral resolution. The TR-MUSIC algorithm is valid only when the number of point-like targets in the imaging plane is fewer than the number of transducer elements used to interrogate the medium. We remedy this shortcoming by dividing the imaging plane into subregions and applying the TR-MUSIC algorithm to the windowed backscattered signals corresponding to each subregion. The images of all subregions are then combined to form the total image. Imaging results of numerical and phantom data show that when the number of scatterers within each subregion is much smaller than the number of transducer elements, the windowing method yields super-resolution images with accurate scatterer localization. We use computer simulations and tissue-mimicking phantom data acquired with a real-time synthetic-aperture ultrasound system to illustrate the algorithms presented in the paper.

关键词： Multiple signal classification Imaging AXIAL algorithms subregion Transducers generalized algorithm

来源：评论

学校读者我要写书评

暂无评论

SYSTEMATIC SOLUTION OF PRIMITIVE ROTATION RECOVERY PROBLEMS OF KNOWN 3-D STRUCTURE FROM A SINGLE VIEW

引用

SYSTEMS AND COMPUTERS IN JAPAN 1994年第7期25卷 59-71页

作者： SHAKUNAGA, T Member NTT Human Interface Laboratories Musashino Japan 180

This paper considers the case where the geometrical model for a 3-D object is given, and discusses the solution of the problem to cover the rotation of the object from a single (monocular) view image. The rigid body is represented by a set of vectors and the joint is represented by a unit vector corresponding to the rotational axis. For each rigid object, the connecting joint is included. The inner product between unit vectors as well as the scalar triple product are assumed as known. Using such a model, not only the rigid body which has widely been discussed, but also the object composed of rigid bodies and joints with the rotational degree of freedom can be handled by the same framework. In the previous paper, it was shown that such a problem to determine the rotational posture of the object can be represented by a graph, and the solvability of the problem is discussed. The basic problem represented by the tree structure is formulated. This paper defines anew the concept of connection index, and classifies the tree-structured basic problems. For the basic problem with the connection index being 0 and 1, an algorithm is proposed which can estimate the rotations of the rigid subobject. The algorithms have the common structure- for each connection index, and can be easily be constructed by defining the geometrical inference inherent to each basic problem. The usefulness of the algorithm is demonstrated through the individual experiments.

关键词： PERSPECTIVE PROJECTION SINGLE VIEW TREE STRUCTURED PRIMITIVE PROBLEM generalized algorithm

来源：评论

学校读者我要写书评

暂无评论

Locally optimal motion planning of nonholonomic systems

引用

JOURNAL OF ROBOTIC SYSTEMS 1997年第11期14卷 767-788页

作者： Duleba, I Institute of Engineering Cybernetics Technical University of Wroc?aw Janiszewskiego 11/17 50-372 Wroc?aw Poland Email: Ignacy Dul?ba (iwd@ict.pwr.wroc.pl)[*]Institute of Engineering Cybernetics Technical University of Wroc?aw Janiszewskiego 11/17 50-372 Wroc?aw Poland

In this article, two algorithms for motion planning of nonholonomic systems based on the Hermes algorithm are presented, called a generalized algorithm and a modified generalized algorithm. The generalized Hermes algorithm gives a locally optimal trajectory while the modified generalized algorithm gives satisfactory results, in the sense of a cost criterion function, with moderate computational effort. The only assumption imposed on the system controlled is controllability. Simulation results presented confirm usefulness of these two algorithms in solving the motion planning task. (C) 1997 John Wiley & Sons, Inc.

关键词： motion planning algorithms criterion function generalized algorithm

来源：评论

学校读者我要写书评

暂无评论

Parameters for system effectiveness evaluation of distributed systems

引用

IEEE TRANSACTIONS ON COMPUTERS 1996年第6期45卷 746-752页

作者： Kumar, A Agrawal, DP N CAROLINA STATE UNIV DEPT ELECT & COMP ENGNRALEIGHNC 27695

In a Distributed Computing System (DCS), the failure of one or more system components causes the degradation in its effectiveness to complete a given task as opposed to a complete network breakdown. This paper addresses the issue of degraded system effectiveness evaluation by introducing two static measures, namely, Distributed Program Performance Index (DPP1) and Distributed System Performance Index (DSPI). These metrics can be used to compare networks with different features for application execution. It can be used to determine if the network with high reliability and bw capacity, or low reliability and high capacity is better for a given program execution. An algorithm is also developed for computing these indices, and a is shown to be not only efficient, but general enough to compute many other existing measures such as computer networks, distributed systems, transaction based systems, etc.

关键词： directed and undirected graphs Distributed Computing System (DCS) Distributed Program Performance Index (DPPI) Distributed System Performance Index (DSPI) generalized algorithm performance degradation system effectiveness

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：