@article{iiasa13592,
          volume = {8},
          number = {1},
           month = {January},
           title = {Guranteed state estimation for dynamical systems: Ellipsoidal techniques},
       publisher = {John Wiley \& Sons, Ltd.},
            year = {1994},
         journal = {International Journal of Adaptive Control and Signal Processing},
             doi = {10.1002/acs.4480080108},
           pages = {85--101},
             url = {https://pure.iiasa.ac.at/id/eprint/13592/},
            issn = {08906327},
        abstract = {This paper gives a concise description of effective solutions to the guaranteed state estimation problems for dynamic systems with uncertain items being unknown but bounded. It indicates a rather unconventional, rigorous theory for these problems based on the notion of evolution equations of the 'funnel' type which could be further transformed - through exact ellipsoidal representations - into algorithmic procedures that allow effective simulation, particularly with computer graphics. the estimation problem is also interpreted as a problem of tracking a partially known system under incomplete measurements.

Mathematically, the technique described in this paper is based on a theory of set-valued evolution equations with the approximation of solutions formulated in terms of set-valued calculus by ellipsoidal-valued functions.},
          author = {Kurzhanski, A. and Sugimoto, K. and Valyi, I.}
}