| 1. |
- Chen, Ke Wang, et al.
(författare)
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Estimation of the Primary Current in a Saturated Transformer
- 1991
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Ingår i: Proceedings of the 30th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780304500 ; , s. 2363-2365 vol.3
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Konferensbidrag (refereegranskat)abstract
- It is pointed out that, when a current in a power system is measured using a transformer, the measurement can be distorted by transformer saturation. The authors examine two methods of estimating the primary current from the secondary in the presence of saturation. The first is based on an extended Kalman filter, while the second is based on an off-line Gauss-Newton method
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| 2. |
- Forsman, Krister
(författare)
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An Algorithm for Finding Periodic Solutions to Systems of Nonlinear Difference Equations
- 1991
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Ingår i: Proceedings of the 30th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780304500 ; , s. 2889-2990 vol.3
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Konferensbidrag (refereegranskat)abstract
- An algorithm for finding all N-periodic solutions to systems of nonlinear difference equations is given. The algorithm is based on elimination theory, and in special Gröbner bases. It is applicable to polynomial systems and can handle indeterminate parameters in the system equations. The system is not required to be in state space form; implicit equations are allowed.
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| 3. |
- Forsman, Krister
(författare)
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Construction of Lyapunov Functions Using Gröbner Bases
- 1991
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Ingår i: Proceedings of the 30th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780304500 ; , s. 798-799 vol.1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we show how so called Grobner bases can be used when choosing parameters in Lyapunov functions for nonlinear dynamical systems in an optimal way. The method suggested requires the nonlinearities of the system and the Lyapunov function to be of polynomial type. Some concrete examples of how to apply the method is provided.
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| 4. |
- Germundsson, Roger, et al.
(författare)
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A Constructive Approach to Algebraic Observability
- 1991
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Ingår i: Proceedings of the 30th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780304500 ; , s. 451-452
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Konferensbidrag (refereegranskat)abstract
- The authors address the problem of observability of polynomial discrete-time systems. The ideal theoretic definition is translated to effective computations in terms of Grobner bases. Linear system observability is a special case, and for general polynomial systems n samples are needed to determine observability, where n is the state dimension. The formulation yields a decision criterion as well as an implicit form of an observer.
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| 5. |
- Glad, Torkel, 1947-
(författare)
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Input Output Representations from Characteristic Sets
- 1991
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Ingår i: Proceedings of the 30th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780304500 ; , s. 726-730 vol.1
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Konferensbidrag (refereegranskat)abstract
- The authors present an algorithm for computation of input-output descriptions. Characteristic sets can be considered as generalization of state space descriptions. Input-output descriptions can also be regarded as characteristic sets under a different ranking. This forms the basis of the differential algebraic algorithm for computation of input-output relations. For polynomial state-space descriptions the calculations are easier than the general computations of characteristic sets.
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| 6. |
- Gunnarsson, Svante
(författare)
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On the Performance of the Recursive Least Squares Method in the Presence of Bounded Disturbances
- 1991
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Ingår i: Proceedings of the 30th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780304500 ; , s. 762-763 vol.1
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Konferensbidrag (refereegranskat)abstract
- The author considers the performance of the recursive least squares method when applied to problems where the measured signal is corrupted by noise, which is bounded but otherwise of unknown characteristics. An asymptotic expression for the bound on the parameter estimation error is derived using ideas from bounding ellipsoid algorithms.
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| 7. |
- Isaksson, Alf, et al.
(författare)
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On Recursive Construction of Trees as Models of Dynamical Systems
- 1991
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Ingår i: Proceedings of the 30th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780304500 ; , s. 1686-1687 vol.2
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Konferensbidrag (refereegranskat)abstract
- An issue that is of importance for control applications is discussed: how to construct the trees online, i.e. recursively, as more and more data become available. A theorem regarding recursive tree-building is stated and proved, and implementation issues are considered.
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| 8. |
- Klein, Inger, et al.
(författare)
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On the Planning Problem in Sequential Control
- 1991
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Ingår i: Proceedings of the 30th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780304500 ; , s. 1819-1823 vol.2
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Konferensbidrag (refereegranskat)abstract
- Sequential control is a common control problem in industry. Despite its importance fairly little theoretical research has been devoted to this problem. We study a subclass of sequential control problems, which we call the SAS-PUBS class, and present a planning algorithm for this class. The algorithm is developed using formalism from articial intelligence (AI). For planning problems in the SAS-PUBS class the algorithm nds a plan from a given initial state to a desired final state if and only if any plan exists solving the stated planning problem. Furthermore the complexity of the given algorithm increases polynomially with the number of state variables.
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| 9. |
- Ljung, Lennart, 1946-
(författare)
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A Simple Start-Up Procedure for Canonical form State Space Identification, based on Subspace Approximation
- 1991
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Ingår i: Proceedings of the 30th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780304500 ; , s. 1333-1336 vol.2
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Konferensbidrag (refereegranskat)abstract
- The authors describe a procedure for estimating parameters in multivariable linear systems, parameterized in pseudo-observability state-space canonical forms. The procedure is based on a standard four-stage instrumental variable method and subsequent operations in the Hankel matrix of estimated impulse responses. The main use of the procedure is for initialization of maximum likelihood/prediction error estimation methods.
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| 10. |
- Ljung, Lennart, 1946-, et al.
(författare)
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Model Quality : The Role of Prior Knowledge and Data Information
- 1991
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Ingår i: Proceedings of the 30th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780304500 ; , s. 273-278
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The authors discuss the basic issues involved in the problem of estimating a model's reliability. In particular, the role of prior information is scrutinized. The modeling errors can be divided into two categories, namely, systematic/bias errors and variability/random errors. All serious system identification experiments contain a model validation step. For an unfalsified model, the bias error has not been found to be significantly larger than the random errors. Hence, the traditional, statistical way to provide estimated standard deviations for the model is relevant for unfalsified models. In the case of many unfalsified models, a sound scientific approach is to choose the most powerful unfalsified one. The definition of most powerful depends on the intended application. For example, in robust control design an unfalsified model can be said to be most powerful if the H∞ error bound is minimized. How this concept relates to minimizing the mean square errors is discussed. A number of questions for further research are identified.
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