Documents disponibles écrits par cet auteur

Bilevel optimizing control structure for a simulated moving bed process based on a reduced-order model using the cubic spline collocation method / Kiwoong Kim in Industrial & engineering chemistry research, Vol. 49 N° 8 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3689–3699 Titre : Bilevel optimizing control structure for a simulated moving bed process based on a reduced-order model using the cubic spline collocation method Type de document : texte imprimé Auteurs : Kiwoong Kim, Auteur ; Kwang Soon Lee, Auteur ; Jay H. Lee, Auteur Année de publication : 2010 Article en page(s) : pp. 3689–3699 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Bilevel  Moving  Bed Résumé : A bilevel strategy for optimizing control of a simulated moving bed (SMB) process is proposed. In the lower level, repetitive model predictive control (RMPC) is used to regulate product purities; in the upper level, optimal feed/desorbent flow rates and the switching period are determined. Both levels employ a fundamental SMB model reduced to a set of nonlinear discrete-time dynamic equations using the cubic spline collocation method and exact discretization. For RMPC, the SMB model is linearized successively along the operating trajectories seen in the previous switching period. It is assumed that the flow rates can be varied within a switching period and the average product purities over each switching period can be measured albeit with a significant analysis delay. Numerical studies using linear isotherms showed that the proposed strategy is successful at driving the process to the intended optimum and maintaining it there while robustly regulating the product purities despite various uncertainties. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901121y [article] Bilevel optimizing control structure for a simulated moving bed process based on a reduced-order model using the cubic spline collocation method [texte imprimé] / Kiwoong Kim, Auteur ; Kwang Soon Lee, Auteur ; Jay H. Lee, Auteur . - 2010 . - pp. 3689–3699. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3689–3699 Mots-clés : Bilevel  Moving  Bed Résumé : A bilevel strategy for optimizing control of a simulated moving bed (SMB) process is proposed. In the lower level, repetitive model predictive control (RMPC) is used to regulate product purities; in the upper level, optimal feed/desorbent flow rates and the switching period are determined. Both levels employ a fundamental SMB model reduced to a set of nonlinear discrete-time dynamic equations using the cubic spline collocation method and exact discretization. For RMPC, the SMB model is linearized successively along the operating trajectories seen in the previous switching period. It is assumed that the flow rates can be varied within a switching period and the average product purities over each switching period can be measured albeit with a significant analysis delay. Numerical studies using linear isotherms showed that the proposed strategy is successful at driving the process to the intended optimum and maintaining it there while robustly regulating the product purities despite various uncertainties. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901121y

Fault detection and diagnosis using hidden markov disturbance models / Wee Chin Wong in Industrial & engineering chemistry research, Vol. 49 N° 17 (Septembre 1, 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7901–7908 Titre : Fault detection and diagnosis using hidden markov disturbance models Type de document : texte imprimé Auteurs : Wee Chin Wong, Auteur ; Jay H. Lee, Auteur Année de publication : 2010 Article en page(s) : pp 7901–7908 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Detection  Diagnosis  Markov  disturbance  models. Résumé : Fault detection and diagnosis is critical for maintaining the health of process systems. Common fault signals include process and disturbance parameter changes, as well as sensor and actuator malfunctions typically manifested as persistent drifts or abrupt biases. These may be characterized by the existence of latent “fault” states. This work examines the effectiveness of a hidden Markov model framework for modeling such fault regimes. The proposed methodology may be interpreted as a generalization of the commonly employed mixture-of-Gaussians approach and is demonstrated through a shell-and-tube heat exchanger problem. Furthermore, the flexibility of the method is shown in the context of detecting valve stiction, a significant problem in the process industries. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020655 [article] Fault detection and diagnosis using hidden markov disturbance models [texte imprimé] / Wee Chin Wong, Auteur ; Jay H. Lee, Auteur . - 2010 . - pp 7901–7908. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 7901–7908 Mots-clés : Detection  Diagnosis  Markov  disturbance  models. Résumé : Fault detection and diagnosis is critical for maintaining the health of process systems. Common fault signals include process and disturbance parameter changes, as well as sensor and actuator malfunctions typically manifested as persistent drifts or abrupt biases. These may be characterized by the existence of latent “fault” states. This work examines the effectiveness of a hidden Markov model framework for modeling such fault regimes. The proposed methodology may be interpreted as a generalization of the commonly employed mixture-of-Gaussians approach and is demonstrated through a shell-and-tube heat exchanger problem. Furthermore, the flexibility of the method is shown in the context of detecting valve stiction, a significant problem in the process industries. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020655

Gray-box model identification of an integrated plant with recycle / Jay H. Lee in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8273–8281 Titre : Gray-box model identification of an integrated plant with recycle Type de document : texte imprimé Auteurs : Jay H. Lee, Auteur ; Thidarat Tosukhowong, Auteur Année de publication : 2008 Article en page(s) : p. 8273–8281 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Dynamic  model  Proposed  gray-boxi Résumé : The objective of this paper is to propose a systematic method for identifying a dynamic model of an integrated plant with recycle for plantwide optimization and control purposes. We are interested in cases where identification experiment is limited to a period of time much shorter than the plant’s settling time. The method is intended to take advantage of prior knowledge about the plant’s steady-state gains. We use an example of an integrated plant composed of a reactor and a distillation column to illustrate the potential issues and to test the effectiveness of the proposed gray-box identification approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071625%2B [article] Gray-box model identification of an integrated plant with recycle [texte imprimé] / Jay H. Lee, Auteur ; Thidarat Tosukhowong, Auteur . - 2008 . - p. 8273–8281. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8273–8281 Mots-clés : Dynamic  model  Proposed  gray-boxi Résumé : The objective of this paper is to propose a systematic method for identifying a dynamic model of an integrated plant with recycle for plantwide optimization and control purposes. We are interested in cases where identification experiment is limited to a period of time much shorter than the plant’s settling time. The method is intended to take advantage of prior knowledge about the plant’s steady-state gains. We use an example of an integrated plant composed of a reactor and a distillation column to illustrate the potential issues and to test the effectiveness of the proposed gray-box identification approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071625%2B