Blar i Institutt for teknisk kybernetikk på forfatter "Backi, Christoph Josef"
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A heat equation for freezing processes with phase change: stability analysis and applications
Backi, Christoph Josef; Bendtsen, Jan Dimon; Leth, John; Gravdahl, Jan Tommy (Journal article, 2016)In this work, the stability properties as well as possible applications of a partial differential equation (PDE) with state-dependent parameters are investigated. Among other things, the PDE describes freezing of foodstuff, ... -
Combined state and parameter estimation for not fully observable dynamic systems
Backi, Christoph Josef; Gravdahl, Jan Tommy; Skogestad, Sigurd (Journal article, 2020)In this paper, a simple, yet novel method for state estimation and parameter identification for dynamic systems is presented. Apart from providing estimates of non-measurable state variables, the algorithm is also capable ... -
Estimation of inner-domain temperatures for a freezing process
Backi, Christoph Josef; Bendtsen, Jan Dimon; Leth, John; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2014)In this paper a state observer for a distributed parameter system (DPS) with nonconstant parameter functions is presented. The DPS describes the freezing of foodstuff in vertical plate freezers and is a nonlinear heat ... -
Modeling of Freezing of Fish by Vertical Plate Freezers
Backi, Christoph Josef; Gravdahl, Jan Tommy (Proceedings of the 17th Nordic Process Control Workshop;, Chapter, 2012) -
Modeling, Estimation and Control of Freezing and Thawing Processes: Theory and Applications
Backi, Christoph Josef (Doctoral thesis at NTNU;2015:323, Doctoral thesis, 2015)Fisheries and aquaculture are very important sectors in the Norwegian industry. Fish and its by-products are considered wholesome foodstuff and are popular especially due to their nutritional value. Therefore, consumer ... -
Nonlinear observer design for a Greitzer compressor model
Backi, Christoph Josef; Gravdahl, Jan Tommy; Grøtli, Esten Ingar (Chapter, 2013)In this paper two different observers for a nonlinear compressor model have been developed and compared: A nonlinear observer based on a circle criterion design and an Extended Kalman Filter. Both of these observers ... -
Optimal boundary control for the heat equation with application to freezing with phase change
Backi, Christoph Josef; Gravdahl, Jan Tommy (Chapter, 2013)In this paper an approach for optimal boundary control of a parabolic partial differential equation (PDE) is presented. The parabolic PDE is the heat equation for thermal conduction. A technical application for this is the ... -
Optimal boundary control of a contact thawing process for foodstuff
Backi, Christoph Josef; Leth, John; Gravdahl, Jan Tommy (Journal article, 2016)In this work an approach for thawing blocks of foodstuff, in particular fish, is introduced. The functional principle is based on plate freezer technology, which has been used in industry for decades. The aim of this work ... -
Simple method for parameter identification of a nonlinear Greitzer compressor model
Backi, Christoph Josef; Gravdahl, Jan Tommy; Skogestad, Sigurd (Journal article; Peer reviewed, 2018)This work introduces a simple method to estimate state variables and identify parameters of a nonlinear dynamic Greitzer compressor model. The observer is based upon an extended Kalman filter, which estimates the dynamic ... -
Stability properties of a heat equation with state-dependent parameters and asymmetric boundary conditions
Backi, Christoph Josef; Bendtsen, Jan Dimon; Leth, John; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2015)In this work the stability properties of a partial differential equation (PDE) with statedependent parameters and asymmetric boundary conditions are investigated. The PDE describes the temperature distribution inside ... -
The nonlinear heat equation with state-dependent parameters and its connection to the Burgers’ and the potential Burgers’ equation
Backi, Christoph Josef; Bendtsen, Jan Dimon; Leth, John; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2014)In this work the stability properties of a nonlinear partial differential equation (PDE) with state dependent parameters is investigated. Among other things, the PDE describes freezing of foodstuff, and is closely related ...