An important control problem is output tracking. One approach, for slightly nonminimum phase systems is to approximate the system by a minimum phase one. Another approach is to track signals generated by an exosystem....
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An important control problem is output tracking. One approach, for slightly nonminimum phase systems is to approximate the system by a minimum phase one. Another approach is to track signals generated by an exosystem. These methods concentrate on properties of the IO system without any attempt to investigate and use structural properties of the IS system. In this paper the authors propose an alternative point of view based on the following simple remark: if one had a state tracker (i.e. a controller able to track any reference state trajectory), the output tracking would reduce to the generation of a good state reference, which is only an open-loop problem, and hence (hopefully) simpler. The idea is simply to split the output tracking problem into two steps.< >
This paper considers the control problem for self-servowriting in disk drives where information propagation occurs in two independent directions, i.e. time and track number respectively. The resulting state-space mode...
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ISBN:
(纸本)9781424431236
This paper considers the control problem for self-servowriting in disk drives where information propagation occurs in two independent directions, i.e. time and track number respectively. The resulting state-space model is not of the well known Roesser or fornasini-marchesini types and hence cannot be analyzed using the theory associated with these 2D discrete linear systems models. Instead, it is shown here that it can written as a discrete linear repetitive process state-space model which is an extension of those already encountered and for which it is necessary to develop new tools for stability analysis and controller design. Finally, the application of these is illustrated by a simulation example using industry supplied data.
Phishing attacks continue to plague users as attackers develop new ways to fool users into submitting personal information to fraudulent sites. Many schemes claim to protect against phishing sites. Unfortunately, most...
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Phishing attacks continue to plague users as attackers develop new ways to fool users into submitting personal information to fraudulent sites. Many schemes claim to protect against phishing sites. Unfortunately, most do not protect against zero-day phishing sites. Those schemes that do allege to provide zero-day protection, often incorrectly label both phishing and legitimate sites. We propose a scheme that protects against zero-day phishing attacks with high accuracy. Our approach captures an image of a page, uses optical character recognition to convert the image to text, then leverages the Google PageRank algorithm to help render a decision on the validity of the site. After testing our tool on 100 legitimate sites and 100 phishing sites, we accurately reported 100% of legitimate sites and 98% of phishing sites.
A method of reliability and functional analysis related to discrete transport systems is presented. The proposed analysis is based on modeling and simulating of the system behavior. Monte Carlo simulation is used for ...
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A method of reliability and functional analysis related to discrete transport systems is presented. The proposed analysis is based on modeling and simulating of the system behavior. Monte Carlo simulation is used for proper reliability and functional parameters calculation. The simulator is built using Scalable Simulation Framework (SSF). No restriction on the system structure and on a kind of distribution is the main advantage of the method. The paper presents some exemplar system modeling. The authors stress the problem of influence of the reliability parameters for final system functional measures (required time of delivery). They also propose to measure the economic quality of discrete transport system by "profit function". The presented problem is practically essential for defining an organization of vehicle maintenance and transport system logistics.
Cartographer is a SLAM (simultaneous localization and map building) algorithm based on graph optimization, which is commonly used for building maps of mobile robots in large indoor scenes, but there are problems of po...
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Cartographer is a SLAM (simultaneous localization and map building) algorithm based on graph optimization, which is commonly used for building maps of mobile robots in large indoor scenes, but there are problems of point cloud data feature loss and motion distortion caused by low frame rate LIDAR in data processing of LIDAR. In this paper, an improved algorithm based on Cartographer algorithm is proposed to address these problems. First, a voxel filtering method with downsampling of neighboring points is used for k-neighborhood search to improve the map building accuracy and computation rate. Then, a wheeled odometer-assisted algorithm is used to remove motion distortions and reduce the cumulative errors that occur in a large scale environment, thus improving the map building effect. Finally, the two algorithms are tested separately by simulating experiments in the gazebo simulation environment in the robot operating system, and the experimental results show that the improved algorithm builds the map trajectory with less error, thus verifying its effectiveness and feasibility.
STATCOM is an important reactive power source in modern power system. The model requirements for electromagnetic or electromechanical transient analysis are quite different. Even though the parameter design method in ...
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STATCOM is an important reactive power source in modern power system. The model requirements for electromagnetic or electromechanical transient analysis are quite different. Even though the parameter design method in Matlab/Simulink is matured the universal parameter design method is still unavailable in PSD-BPA. The typical topology and working principles of STATCOM are analysed firstly in this paper. The mathematical models of STATCOM in Matlab/Simulink for electromagnetic transient analysis and mathematical models of STATCOM in PSD-BPA for electromechanical transient analysis are presented respectively. Both d axis and q axis control loops are presented in the detailed model of Matlab/Simulink. The d axis loop controls the bus voltage / reactive power while q axis loop controls the DC voltage. There are two types of STATCOM models in PSD-BPA. The STATCOM is regarded as a controlled voltage source in one type and a controlled current source in the other. Both models contain bus voltage control loop and the DC voltage control loop is ignored since PSD-BPA focus on grid analysis. The dynamic responses of the two simulation platforms are compared afterwards. The typical parameter design method for detailed model in Matlab/Simulink is presented. The control link functions are analysed and a universal parameter design method for PSD-BPA is illustrated according to the detailed model in Matlab/Simulink.
This paper presents a parallel VLSI architecture for fast line drawing. The architecture implements a non incremental line drawing algorithm which allows to write simultaneously in a memory array all the pixels that a...
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This paper presents a parallel VLSI architecture for fast line drawing. The architecture implements a non incremental line drawing algorithm which allows to write simultaneously in a memory array all the pixels that approximate the straight segments. This paper explains the bottom-zip process for a simplified architecture design that reduces the circuitry redundancies in order to minimize the area. This memory architecture also provides read/write random accesses and raster outputs that permit the memory architecture to display the data serially. A 256/spl times/256 eight-bit pixel processor array has been designed using a 0.35 /spl mu/m standard cells. An exhaustive test and simulation results upon this design have demonstrated that a rate of 50 M segments per second can be achieved, independently of their length and orientation.
Few responsibilities are greater for a control system than the reliable running of a waterworks, as failure to keep the water flowing for 24 hours a day leads to expensive and awkward workarounds. However, one Danish ...
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Few responsibilities are greater for a control system than the reliable running of a waterworks, as failure to keep the water flowing for 24 hours a day leads to expensive and awkward workarounds. However, one Danish facility has found a way to enable its personnel to monitor water quantity, pressure drops and salinity directly on their PCs. The works in Ballerup, near Copenhagen, is in the middle of a modernisation programme that will see technicians provided with direct access to large amounts of data that, among other things, will allow them to check for leaks in pipes.
The GE multidisciplinary expert-aided analysis and design (MEAD) project, which involves the integration of several computer-aided controlengineering (CACE) packages under a supervisor which coordinates the execution...
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The GE multidisciplinary expert-aided analysis and design (MEAD) project, which involves the integration of several computer-aided controlengineering (CACE) packages under a supervisor which coordinates the execution of these packages with a database manager, an expert system, and an advanced user interface, is discussed. The principal components are, in functional terms: a supervisor, which integrates the underlying CACE packages and coordinates all activity within the GE MEAD computer program (GMCP); an expert system shell and rule bases for expert aiding of specific procedures to relieve the user from unnecessary low-level detail; a database manager for tracking system models that evolve over time along with associated results; and a user interface that facilitates access to the CACE package capabilities by permitting the user to work in several modalities, i.e. menu/forms style, using GE MEAD commands, the core packages' native commands, or the GE MEAD macro facility. The operation of the GMCP, including the user interface, expert system, and database manager, is illustrated by examples.< >
In order to take into account the interaction between the part, dynamic system, control system, and changing mechanical behavior with all its consequences for the optimization process, a simulation of the complete mec...
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In order to take into account the interaction between the part, dynamic system, control system, and changing mechanical behavior with all its consequences for the optimization process, a simulation of the complete mechatronic system is integrated into the optimization process within the research work presented in this paper. A hybrid multibody system (MBS) simulation, that is a MBS containing flexible bodies, in conjunction with a cosimulation of the control system represented by tools of the computer aided controlengineering, is integrated into the optimization process. By an inner optimization loop the controller parameters are adopted new in each of the iterations of the topology optimization in order to provide realistic load cases. The benefits will be illustrated by an example in conjunction with the humanoid robot ARMAR III of the Collaborative Research Centre 588 "Humanoid Robots-Learning and Cooperating Multimodal Robots" in Karlsruhe Germany. It will be shown how the new approach for the optimization of parts "within" their surrounding mechatronic system allows an efficient optimization of such structures.
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