State and Unknown Input Simultaneous Estimation for a Class of Discrete-Time Linear Implicit Models : A Heat Exchanger Pilot Process ApplicationKarim Bouassem, El Mahfoud El Bouatmani, Abdellatif El Assoudi and El Hassane El YaagoubiE3S Web Conf., 297 (2021) 01011DOI: https://doi.org/10.1051/e3sconf/202129701011