摘要:

A heuristic procedure for the segmentation of 3-D range images is presented. The range image is coarsely segmented into convex, concave, and flat patches using curvature sign labelling at each surface point. The jump edges are then imposed on the coarsely segmented image, resulting in the initial image segmentation. Next, the boundary points between adjacent surface patches are examined for the purpose of merging compatible patches. A boundary point between patches, which is not on a jump edge, has to belong to a crease or to a ridge line. This is detected by the presence of a large local norm of the residuals for an approximating plane on a window surrounding the boundary point. The present method is expected to be faster than many existing methods. Two examples are used in illustration. Comments and conclusions are given.

ISSN:0020-7721    

DOI:10.1080/00207729008910359

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The interconnections of subsystems are structurally decomposed and the stability of the overall large-scale system is then investigated, based on these decompositions. With these formulations, the decentralized control design for the interconnected subsystems can be treated as an algebraic problem. The architecture is then extended to solve the decentralized estimation and stabilization problem. The emphasis here is to propose a new method for the qualitative analysis and design of large-scale systems. The advantage lies in its feasibility for a computer-aided control system design (CACSD) set-up.

ISSN:0020-7721    

DOI:10.1080/00207729008910360

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A methodology is developed for the statistical modelling of cardiac behaviour and electrocardiograms (ECGs) thai emphasizes (a) the physiological event/detailed waveform hierarchy; and (b) the importance of control and timing in describing the interactions among the several anatomical sub-units of the heart. This methodology has been motivated by a desire to develop improved algorithms for statistical rhythm analysis. Specifically, to develop algorithms that capture cardiac behaviour in a more fundamental way but that stop short of complete accuracy in order to highlight decompositions that can be exploited to simplify statistical inference based on these models. Our models consist of interacting finite-state processes, where a very few of the transition probabilities for each process can take on a small number of different values depending upon the states of neighbouring processes. Each finite-state process is constructed from a very small set of elementary structural elements. We illustrate our methodology by describing models for three cardiac rhythms and include simulation results for one of these, namely the rhyihm known as Wenckebach.

ISSN:0020-7721    

DOI:10.1080/00207729008910361

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The problem of estimating the state of a distributed finite-state Markov process consisting of several interacting finite-state systems each of whose transition probabilities are influenced by the states of the other processes is examined. The observations on which the estimation procedure is based are continuous signals containing signatures indicative of the occurrence of particular events in the various finite-state systems. The problem of electrocardiogram analysis serves both as the primary motivation for this investigation and as the source of a case study we describe. The principal focus of the paper is on the development of an approach that overcomes the combinatorial explosion of truly optimal estimation algorithms. We accomplish this by constructing a systematic design methodology in which the resulting estimator consists of several interacting estimators, each focusing on a particular sub-process, Important questions that we address concern the way in which these estimators interact and the method each estimator uses to account for the influence of other sub-processes in its own model.

ISSN:0020-7721    

DOI:10.1080/00207729008910362

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

It is demonstrated for the first time that the new criteria developed by Chang and Chen (1988), for a linear multivariable system to guarantee the stability of systems subjected to non–linear time–varying uncertainties, are not only sufficient but are also necessary ones. In addition, it is also shown that the previous results can be extended to a more simple and testable form which just contains the unstable part of the plant, to facilitate the analysis and synthesis of system robustness. An illustrative example confirms the availability of these new results.

ISSN:0020-7721    

DOI:10.1080/00207729008910363

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The robustness of solutions to the problem of pole placement obtained by the frequency–domain approach is examined. A more intuitive and general criterion that is necessary and sufficient for guaranteeing the located region of system poles is obtained. This new result is presented for all of open, closed or united regions and is applicable to both the continuous–time and to the discrete–time cases. The parumetrization of all admissible pole–region placement controllers is also introduced. In addition, a simplified criterion is provided to facilitate the analysis and synthesis of complex and high–order systems. When the system poles are requested to locate only in the left half–plane or the unit circle, the proposed result would become a similar but evidently less conservative condition of the stability robustness.

ISSN:0020-7721    

DOI:10.1080/00207729008910364

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Robust dynamic output feedback controllers are extended to piecewise-linear system models allowing for non-linearities. The design has been applied to an SCR operated DC-servo motor. A robust design is also found when a long shaft of the DC motor is assumed. The design is repeated where a finite delay T in the firing angle of the power electronics (SCR circuit) is incorporated.

ISSN:0020-7721    

DOI:10.1080/00207729008910365

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The controllability and observability gramians in limited time and frequency intervals are studied, and used for model reduction. In balanced and modal coordinates, a near – optimal reduction procedure is used, vielding the reduction error (norm of the different between the output of the orginal system and the reduced model) almost minimal. Several examples are given to illustrate the concept of model reduction in limited time or/and frequency intervals, for continuous- and discrete-time systems, as well as stable and unstable systems. In modal coordinates, the reduced model obtained from a stable system is always stable. In balanced coordinates it is not necessarily true, and stability conditions for the balanced reduced model are presented. Finally, model reduction is applied to advanced supersonic transport and a flexible truss structure.

ISSN:0020-7721    

DOI:10.1080/00207729008910366

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Criteria are developed for a partially closed branched trophic chain originating from a resource with global sector stability or partially feasible equilibria. Criteria under which such a trophic chain exhibits persistence are also developed.

ISSN:0020-7721    

DOI:10.1080/00207729008910367

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The feasibility of decentralized control and observation of flight control systems is considered. It is shown that, by decomposition and input and output decentralization, reliable compensators can be designed to obtain suboptimal and exponentially stable flight control systems, Local and active control can be implemented with a minimum amount of information exchange and distributed control is made possible. The results arc applied to develop flight control for a model of L-1011 aircraft lateral axis rigid body motion.

ISSN:0020-7721    

DOI:10.1080/00207729008910368

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor