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991.
In this paper, a multivariable direct adaptive controller using multiple models without minimum phase assumption is presented
to improve the transient response when the parameters of the system jump abruptly. The controller is composed of multiple
fixed controller models, a free-running adaptive controller model and a re-initialized adaptive controller model. The fixed
controller models are derived from the corresponding fixed system models directly. The adaptive controller models adopt the
direct adaptive algorithm to reduce the design calculation. At every instant, the optimal controller is chosen out according
to the switching index. The interaction of the system is viewed as the measured disturbance which is eliminated by the choice
of the weighing polynomial matrix. The global convergence is obtained. Finally, several simulation examples in a wind tunnel
experiment are given to show both effectiveness and practicality of the proposed method. The significance of the proposed
method is that it is applicable to a non-minimum phase system, adopting direct adaptive algorithm to overcome the singularity
problem during the matrix calculation and realizing decoupling control for a multivariable system.
Supported by the National Natural Science Foundation of China (Grant Nos. 60504010, 60864004), the National High-Tech Research
and Development Program of China (Grant No. 2008AA04Z129), the Key Project of Chinese Ministry of Education (Grant No. 208071),
and the Natural Science Foundation of Jiangxi Province (Grant No. 0611006) 相似文献
992.
This paper designs and analyzes switching fuzzy reduced-order observer and proves that the corresponding separation principle
does hold. A numerical simulation and comparison with smooth fuzzy full-order observer are given to assess switching fuzzy
reduced-order observer and the validity of the separation principles.
Supported by the National Laboratory of Space Intelligent Control and Open Foundation (Grant No. SIC07010202), and the National
Natural Science Foundation of China (Grant Nos. 60604010, 90716021, 60736023) 相似文献
993.
Fotis N. Koumboulis Nikolaos D. Kouvakas Paraskevas N. Paraskevopoulos 《中国科学F辑(英文版)》2009,52(7):1084-1094
In the present paper the problem of disturbance rejection of single input-single output neutral time delay systems with multiple
measurable disturbances is solved via dynamic controllers. In particular, the general form of the controller matrices is presented,
while the necessary and sufficient conditions for the controller to be realizable are offered. The proposed technique is applied
to a test case neutral time delay central heating system. In particular, the nonlinear model of the plant and its linearized
approximation are presented. Based on the linearized model, a two-stage controller is designed in order to regulate the room
temperature and the boiler effluent temperature. The performance of the closed loop system is investigated through computational
experiments. 相似文献
994.
How to compose existing web services automatically and to guarantee the correctness of the design(e.g. freeness of deadlock and unspecified reception,and temporal constraints) is an important and challenging problem in web services. Most existing approaches require a detailed specification of the desired behaviors of a composite service beforehand and then perform certain formal verification to guarantee the correctness of the design,which makes the composition process both complex and time-consuming. In th... 相似文献
995.
LiQiang Zhang ZhiFeng Guo ZhiZhong Kang LiXin Zhang XingMing Zhang Ling Yang 《中国科学F辑(英文版)》2009,52(9):1588-1597
Adaptive rendering large and complex spatial data has become an important research issue in a 3DGIS application. In order to transmit the data to the client efficiently,this paper proposes a node-layer data model to manage the 3D scene. Because the large spatial data and limited network bandwidth are the main bottlenecks of web-based 3DGIS,a client/server architecture including progressive transmission methods and multiresolution representations,together with the spatial index,are developed to improve the p... 相似文献
996.
997.
Perfect forward secure identity-based authenticated key agreement protocol in the escrow mode 总被引:1,自引:0,他引:1
CHOO Kim-Kwang Raymond 《中国科学F辑(英文版)》2009,52(8):1358-1370
The majority of existing escrowable identity-based key agreement protocols only provide partial forward secrecy. Such protocols are, arguably, not suitable for many real-word applications, as the latter tends to require a stronger sense of forward secrecy—perfect forward secrecy. In this paper, we propose an efficient perfect forward-secure identity-based key agreement protocol in the escrow mode. We prove the security of our protocol in the random oracle model, assuming the intractability of the Gap Biline... 相似文献
998.
KangWoo Lee 《计算机科学技术学报》2008,23(5):874-884
A common assumption in visual attention is based on the rationale of "limited capacity of information processing". From this view point there is little consideration of how different information channels or modules are cooperating because cells in processing stages are forced to compete for the limited resource. To examine the mechanism behind the cooperative behavior of information channels, a computational model of selective attention is implemented based on two hypotheses. Unlike the traditional view of visual attention, the cooperative behavior is assumed to be a dynamic integration process between the bottom-up and top-down information. Furthermore, top-down information is assumed to provide a contextual cue during selection process and to guide the attentional allocation among many bottom-up candidates. The result from a series of simulation with still and video images showed some interesting properties that could not be explained by the competitive aspect of selective attention alone. 相似文献
999.
Xin-Dong Wu 《计算机科学技术学报》2009,24(6):1018-1027
Due to the increasing availability and sophistication of data recording techniques, multiple information sources and distributed
computing are becoming the important trends of modern information systems. Many applications such as security informatics
and social computing require a ubiquitous data analysis platform so that decisions can be made rapidly under distributed and
dynamic system environments. Although data mining has now been popularly used to achieve such goals, building a data mining
system is, however, a nontrivial task, which may require a complete understanding on numerous data mining techniques as well
as solid programming skills. Employing agent techniques for data analysis thus becomes increasingly important, especially
for users not familiar with engineering and computational sciences, to implement an effective ubiquitous mining platform.
Such data mining agents should, in practice, be intelligent, complete, and compact. In this paper, we present an interactive
data mining agent — OIDM (online interactive data mining), which provides three categories (classification, association analysis,
and clustering) of data mining tools, and interacts with the user to facilitate the mining process. The interactive mining
is accomplished through interviewing the user about the data mining task to gain efficient and intelligent data mining control.
OIDM can help users find appropriate mining algorithms, refine and compare the mining process, and finally achieve the best
mining results. Such interactive data mining agent techniques provide alternative solutions to rapidly deploy data mining
techniques to broader areas of data intelligence and knowledge informatics. 相似文献
1000.
Yi-Song Wang 《计算机科学技术学报》2009,24(6):1125-1137
Logic programming under the stable model semantics is proposed as a non-monotonic language for knowledge representation and
reasoning in artificial intelligence. In this paper, we explore and extend the notion of compatibility and the Λ operator, which were first proposed by Zhang to characterize default theories. First, we present a new characterization
of stable models of a logic program and show that an extended notion of compatibility can characterize stable submodels. We further propose the notion of weak auto-compatibility which characterizes the Normal Forward Chaining Construction proposed by Marek, Nerode and Remmel. Previously, this construction was only known to construct the stable models of FC-normal
logic programs, which turn out to be a proper subclass of weakly auto-compatible logic programs. We investigate the properties
and complexity issues for weakly auto-compatible logic programs and compare them with some subclasses of logic programs. 相似文献