检索结果-内蒙古大学图书馆

COMPARING CODING EFFICIENCY OF VECTOR CHAIN CODING AND RUN-LENGTH CODING FOR LINE DRAWINGS

IEE PROCEEDINGS-I COMMUNICATIONS SPEECH AND VISION 1991年第5期138卷 363-370页

作者： KUN, L PRASAD, R Department of Electrical Engineering Telecommunications and Traffic Control Systems Group Delft University of Technology Delft Netherlands

More efficient data compression can be achieved in encoding line drawings by vector chain coding (VCC) than by the traditional runlength coding (RLC), provided the total length of the lines within a line drawing is not excessive. More bandwidth or time can thus be saved in transmitting such pictures by using VCC. Although this has so far been established only intuitively, quantitative analysis and comparison of the coding efficiency of these two codes for line drawings are performed in this paper. The coding efficiency is measured in terms of both per-length coding rate and data compression ratio, which are determined for a class of handwritten line drawings characterised by a proper statistical model. In particular, the critical point of line drawing complexity is derived at which VCC becomes less efficient than RLC. Experimental observations are also presented to verify the theoretical results.

关键词： CODING EFFICIENCY RUN-LENGTH CODING VECTOR CHAIN CODING IMAGE PROCESSING

来源：评论

学校读者我要写书评

暂无评论

PERFORMANCE ANALYSIS OF MOBILE PACKET RADIO NETWORKS IN REAL CHANNELS WITH INHIBIT-SENSE MULTIPLE ACCESS

引用

IEE PROCEEDINGS-I COMMUNICATIONS SPEECH AND VISION 1991年第5期138卷 458-464页

作者： PRASAD, R Telecommunications and Traffic Control Systems Group Department of Electrical Engineering Delft University of Technology Delft Netherlands

Coherent cumulation of interference signals is modelled in an environment of Rayleigh fading and log-normal shadowing under the influence of near-far effect. The interference model is used to investigate the performance of mobile packet radio networks using the inhibit-sense multiple access protocol. Numerical results are presented, indicating the effect of individual and combined propagation impairments on channel capacity. It is shown that the combined effect of propagation impairments of the real channel enhances the channel capacity.

关键词： NOISE AND INTERFERENCE RADIOCOMMUNICATION PACKET RADIO

来源：评论

学校读者我要写书评

暂无评论

Identifiability in dynamic network identification

引用

IFAC-PapersOnLine 2015年第28期48卷 1409-1414页

作者： Weerts, Harm H.M. Dankers, Arne G. Van den Hof, Paul M.J. Control Systems Group Department of Electrical Engineering Eindhoven University of Technology Netherlands Department of Electrical Engineering University of Calgary Canada

Dynamic networks are structured interconnections of dynamical systems driven by external excitation and disturbance signals. We develop the notion of network identifiability, a property of a parameterized model set that ensures that module dynamics are uniquely related to the filters that specify the one-step-ahead predictors of all node signals in the network. It can be used to specify which presence of excitation signals will result in a unique representation of the network dynamics in a particular network model parametrization. This uniqueness is necessary for detecting the topology of the network from measured data, and for consistently estimating the network dynamics. We combine aspects of the classical notion of system identifiability with a uniqueness-oriented parametrization concept, and extend this to the situation of highly structured model sets. All node signals in the network are treated in a symmetric way. The presented concept and theory allow for the incorporation of particular structural prior knowledge of the network structure © 2015

关键词： Dynamics Dynamical systems Identification (control systems) Disturbance signals Dynamic network Excitation signals External excitation Identifiability Network structures Parameterized model Parametrizations

来源：评论

学校读者我要写书评

暂无评论

Identifiability of dynamic networks with part of the nodes noise-free

引用

IFAC-PapersOnLine 2016年第13期49卷 19-24页

作者： Weerts, Harm H.M. Van den Hof, Paul M.J. Dankers, Arne G. Control Systems Group Department of Electrical Engineering Eindhoven University of Technology Netherlands Department of Electrical Engineering University of Calgary Canada

In dynamic network identification a major goal is to uniquely identify the topology and dynamic links between the measured node variables. It is common practice to assume that process noises affect every output in multivariable system identification, and every node in dynamic networks with a full rank noise process. For many practical situations this assumption might be overly strong. This leads to the question of how to handle situations where the process noise is not full rank, i.e. when the number of white noise processes driving the network is strictly smaller than the number of nodes. In this paper a first step towards answering this question is taken by addressing the case of a dynamic network where some nodes are noise-free, and others are disturbed with a (correlated) process noise. In this situation the predictor filters that generate the one-step-ahead prediction of the node signals are non-unique, and the appropriate identification criterion leads to a constrained optimization problem. It is assessed when it is possible to distinguish between models on the basis of this criterion, leading to new notions of network identifiability. It appears that a sufficient condition for network identifiability is that every node signal in the network is excited by an external excitation signal or a process noise signal that is uncorrelated with other node excitations. © 2016

关键词： White noise Constrained optimization Identification (control systems) Multivariable systems Religious buildings Topology Constrained optimi zation problems Dynamic network External excitation Identifiability Identification criterion Network topology Noise process White noise process

来源：评论

学校读者我要写书评

暂无评论

ERROR FEEDBACK AND INTERNAL MODELS ON DIFFERENTIABLE MANIFOLDS

引用

IEEE TRANSACTIONS ON AUTOMATIC control 1984年第5期29卷 397-403页

作者： HEPBURN, JSA WONHAM, WM Systems Control Group Department of Electrical Engineering University of Toronto Toronto ONT Canada

Structural aspects are studied of nonlinear control systems in a setting of differentiable manifolds. As a generalization of the setup commonly used in linear multivariable control, the regulator problem is defined as that of controlling a fixed plant to track (or reject) reference (or disturbance) signals generated by a fixed dynamic model called the exosystem. It is shown that, if the controller is error-driven, if perfect tracking is achieved in the limit t \rightarrow \infty , and if a suitable observability condition is present, then the controller necessarily incorporates a copy (internal model) of the exosystem dynamics. This result represents a counterpart in the nonlinear differentiable setting to various results already known for linear systems and for abstract automata.

关键词： State-space methods Regulators Nonlinear dynamical systems Automatic control Nonlinear control systems Signal generators Tracking loops Feedback loop Error correction Observability

来源：评论

学校读者我要写书评

暂无评论

FEEDBACK-systems IN A GENERAL ALGEBRAIC SETTING

引用

IEEE TRANSACTIONS ON CIRCUITS AND systems 1978年第9期25卷 728-741页

作者： LIEPA, PE WONHAM, WM Systems Control Group Department of Electrical Engineering University of Toronto Toronto ONT Canada

The "geometric" theory of [1] is extended to a universal algebraic setting. Of central interest are the subalgebra and congruence lattices of the state algebra: for example, distinguished systems objects such as the reachability subalgebra are extremal fixpoints of mappings defined on these lattices. Conditions are given for the solvability of an abstract disturbance decoupling problem.

关键词： Feedback Lattices Algebra control system synthesis Observability Tiles State-space methods Strips Councils Scholarships

来源：评论

学校读者我要写书评

暂无评论

A PMGOP METHOD OF PARAMETER-IDENTIFICATION FOR A CLASS OF CONTINUOUS NONLINEAR-systems

引用

INTERNATIONAL JOURNAL OF control 1995年第2期62卷 349-378页

作者： HU, YZ DAVISON, EJ Systems Control Group Department of Electrical and Computer Engineering University of Toronto Toronto Ontario Canada M5S 1A4

A series of piecewise multiple general orthogonal polynomials (PMGOPs) is introduced and applied to the parameter identication problem for a class of continuous nonlinear systems. After introducing PMGOPs and discussing their main properties, an effective procedure for the parameter identification of a large class of continuous systems, called parameter separable systems, is proposed. Some relevant algorithms are presented. The procedure given in the paper has the following advantages compared with other methods: the identification algorithm (IA) obtained is computationally fast and accurate;the IA can be implemented in a recursive fashion;the IA is effective for a small number of data points;the IA does not require a priori knowledge of the estimated parameters;the IA is tolerant to choices of expanding orders when PMGOPs are applied. Some numerical examples, together with an experimental example taken from a biochemical fermentation process, are given for illustrative purposes.

关键词： Identification (control systems)

来源：评论

学校读者我要写书评

暂无评论

Robust Continuous-Time Generation Scheduling under Power Demand Uncertainty: An Affine Decision Rule Approach

arXiv

引用

arXiv 2025年

作者： Cho, Youngchae Yang, Insoon Ishizaki, Takayuki Department of Systems and Control Engineering Institute of Science Tokyo Tokyo Japan Department of Electrical and Computer Engineering ASRI Seoul National University Seoul Korea Republic of

Most existing generation scheduling models for power systems under demand uncertainty rely on energy-based formulations with a finite number of time periods, which may fail to ensure that power supply and demand are balanced continuously over time. To address this issue, we propose a robust generation scheduling model in a continuous-time framework, employing a decision rule approach. First, for a given set of demand trajectories, we formulate a general robust generation scheduling problem to determine a decision rule that maps these demand trajectories and time points to the power outputs of generators. Subsequently, we derive a surrogate of it as our model by carefully designing a class of decision rules that are affine in the current demand, with coefficients invariant over time and constant terms that are continuous piecewise affine functions of time. As a result, our model can be recast as a finite-dimensional linear program to determine the coefficients and the function values of the constant terms at each breakpoint, solvable via the cutting-plane method. Our model is non-anticipative unlike most existing continuous-time models, which use Bernstein polynomials, making it more practical. We also provide illustrative numerical examples. Copyright © 2025, The Authors. All rights reserved.

关键词： Continuous time systems

来源：评论

学校读者我要写书评

暂无评论

Fast implementation of the forward positional acceleration of robots via the distributed arithmetic technique

引用

CIRCUITS systems AND SIGNAL PROCESSING 1997年第2期16卷 165-195页

作者： Grigoriadis, GK Mertzios, BG Automatic Control Systems Laboratory Department of Electrical and Computer Engineering Dimocritus University of Thrace Xanthi Greece

This paper refers to the fast implementation of the positional forward acceleration of the end effector of revolute robotic arms with spherical wrists, using the distributed arithmetic technique. The acceleration of the end effector is calculated by a cascade configuration of two pipelined arrays that calculate the Jacobian matrix and its time derivative, as well as the centrifugal-Coriolis and linear accelerations. These partial accelerations are then added in the adder tree. The building blocks of the arrays are the distributed arithmetic-based circuits that implement the matrix-vector multiplications involved in the calculations. The digit-serial configuration of the proposed implementation of the positional forward acceleration of the end effector is described. The serial and the parallel configurations may result as special cases of the digit-serial configuration. The proposed distributed arithmetic (DA) implementation of the positional forward acceleration may be applied, after appropriate modifications, to the general case of robots having either revolute or prismatic joints, with any type of wrist.

关键词： End effectors

来源：评论

学校读者我要写书评

暂无评论

Internal force-based impedance control for cooperating manipulators

引用

IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION 1996年第1期12卷 78-89页

作者： Bonitz, RG Hsia, TC Systems Controland Robotics LaboratoryDepartment of Electrical and Computer Engineering University of California Davis CA USA

An internal force-based impedance control scheme for cooperating manipulators is introduced which controls the motion of the objects being manipulated and the internal force on the objects. The controller enforces a relationship between the velocity of each manipulator and the internal force on the manipulated objects. Each manipulator is directly given the properties of an impedance by the controller;thus, eliminating the gain limitation inherent in the structure of previously proposed schemes. The controller uses the forces sensed at the robot end effecters to compensate for the effects of the objects' dynamics and to compute the internal force using only kinematic relationships. Thus, knowledge of the objects' dynamics is not required. Stability of the system is proven using Lyapunov theory and simulation results are presented validating the proposed concepts. The effect of computational delays in digital control implementations is analyzed vis-a-vis stability and a lower bound derived on the size of the desired manipulator inertia relative to the actual manipulator endpoint inertia. The bound is independent of the sample time.

关键词： Impedance Force control Motion control Manipulator dynamics Velocity control Robot sensing systems End effectors Kinematics Stability Computational modeling

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：