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Control variance amplification in linear time invariant decentralized supply chains / Hua Xu in Industrial & engineering chemistry research, Vol. 49 N° 18 (Septembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8644–8656 Titre : Control variance amplification in linear time invariant decentralized supply chains : a minimum variance control perspective Type de document : texte imprimé Auteurs : Hua Xu, Auteur ; Gang Rong, Auteur ; Yiping Feng, Auteur Année de publication : 2010 Article en page(s) : pp. 8644–8656 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Supply  chains Résumé : This paper addresses demand uncertainty and its propagation in supply chains. The supply chain is considered as a linear time invariant (LTI) system driven by stochastic customer demand. Under general ARMA demand patterns and arbitrary lead times, a unified and structured framework based on the classical minimum variance control theory is proposed for decentralized supply chain management (SCM). Optimal forecasting, the traditional order-up-to policy and the generalized order-up-to policy are directly derived according to the minimum variance criterion. Given these strategies, stochastic properties of the supply chain are studied using LTI system theory in both the time and the frequency domain. Findings from previous literature are reinterpreted from a control-theory-oriented perspective, and new characteristics of the generalized order-up-to policy are deduced and analyzed. On the basis of the statistical analysis, an optimization model is constructed to minimize the variable operation costs which are related to the parameters of the SCM strategies. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100167u [article] Control variance amplification in linear time invariant decentralized supply chains : a minimum variance control perspective [texte imprimé] / Hua Xu, Auteur ; Gang Rong, Auteur ; Yiping Feng, Auteur . - 2010 . - pp. 8644–8656. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8644–8656 Mots-clés : Supply  chains Résumé : This paper addresses demand uncertainty and its propagation in supply chains. The supply chain is considered as a linear time invariant (LTI) system driven by stochastic customer demand. Under general ARMA demand patterns and arbitrary lead times, a unified and structured framework based on the classical minimum variance control theory is proposed for decentralized supply chain management (SCM). Optimal forecasting, the traditional order-up-to policy and the generalized order-up-to policy are directly derived according to the minimum variance criterion. Given these strategies, stochastic properties of the supply chain are studied using LTI system theory in both the time and the frequency domain. Findings from previous literature are reinterpreted from a control-theory-oriented perspective, and new characteristics of the generalized order-up-to policy are deduced and analyzed. On the basis of the statistical analysis, an optimization model is constructed to minimize the variable operation costs which are related to the parameters of the SCM strategies. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100167u

Planning under Demand and Yield Uncertainties in an Oil Supply Chain / Kailiang Tong in Industrial & engineering chemistry research, Vol. 51 N° 2 (Janvier 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 2 (Janvier 2012) . - pp. 814-834 Titre : Planning under Demand and Yield Uncertainties in an Oil Supply Chain Type de document : texte imprimé Auteurs : Kailiang Tong, Auteur ; Yiping Feng, Auteur Année de publication : 2012 Article en page(s) : pp. 814-834 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Uncertainty  Planning Résumé : In this article, a stochastic programming approach for an optimal refinery planning problem under uncertainties is proposed. The nominal planning model is extended by means of conditional value-at-risk theory. Demand amount uncertainty and product yield fluctuation are taken into account simultaneously. The risk of customer dissatisfaction and inventory violation are considered as constraints according to the decision maker's risk tolerance. Sample average approximation approach is employed to test the robustness of the model and determine the suitable risk aversion value. A more accurate product yield distribution based upon a Markov chain is introduced and applied in this model. A problem with such endogenous uncertainty is solved using a heuristic iterative algorithm integrating stochastic programming and simulation framework. Also, the scenario number in the stochastic programming model is determined by a statistical analysis, which is a compromise of model accuracy and problem size. At the end of this article, a comprehensive analysis is presented to illustrate the effectiveness of the proposed model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25476416 [article] Planning under Demand and Yield Uncertainties in an Oil Supply Chain [texte imprimé] / Kailiang Tong, Auteur ; Yiping Feng, Auteur . - 2012 . - pp. 814-834. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 2 (Janvier 2012) . - pp. 814-834 Mots-clés : Uncertainty  Planning Résumé : In this article, a stochastic programming approach for an optimal refinery planning problem under uncertainties is proposed. The nominal planning model is extended by means of conditional value-at-risk theory. Demand amount uncertainty and product yield fluctuation are taken into account simultaneously. The risk of customer dissatisfaction and inventory violation are considered as constraints according to the decision maker's risk tolerance. Sample average approximation approach is employed to test the robustness of the model and determine the suitable risk aversion value. A more accurate product yield distribution based upon a Markov chain is introduced and applied in this model. A problem with such endogenous uncertainty is solved using a heuristic iterative algorithm integrating stochastic programming and simulation framework. Also, the scenario number in the stochastic programming model is determined by a statistical analysis, which is a compromise of model accuracy and problem size. At the end of this article, a comprehensive analysis is presented to illustrate the effectiveness of the proposed model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25476416

Thermally on−off switching membranes prepared by pore-filling poly(N-isopropylacrylamide) hydrogels / Wang, Wencai in Industrial & engineering chemistry research, Vol. 49 N° 4 (Fevrier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1684–1690 Titre : Thermally on−off switching membranes prepared by pore-filling poly(N-isopropylacrylamide) hydrogels Type de document : texte imprimé Auteurs : Wang, Wencai, Auteur ; Tian, Xiaodong, Auteur ; Yiping Feng, Auteur Année de publication : 2010 Article en page(s) : pp 1684–1690 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymer  hydrogels  Switching  membranes. Résumé : Pore-filling N-isopropylacrylamide (NIPAAM) polymer hydrogels were successfully grafted onto track-etched polycarbonate (PC) membranes by plasma-induced graft copolymerization. The microstructure and morphology of the PC-g-PNIPAAM membranes were investigated by XPS, SEM, ATR-FTIR, TGA, and water flux experiments. The effective pore sizes were regulated by the volume change of the cross-linked PNIPAAM hydrogels in the temperature range around its lower critical solution temperature (LCST). The PC-g-PNIPAAM membranes demonstrated a fast and reversible valve switching mechanism in a small temperature range. The on−off water flux ratio became more significant with the increase of the monomer concentration. Contact angle results showed that the thermal-responsive gating characteristics of PC-g-PNIPAAM membranes were mainly dependent on the pore size change DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9008666 [article] Thermally on−off switching membranes prepared by pore-filling poly(N-isopropylacrylamide) hydrogels [texte imprimé] / Wang, Wencai, Auteur ; Tian, Xiaodong, Auteur ; Yiping Feng, Auteur . - 2010 . - pp 1684–1690. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1684–1690 Mots-clés : Polymer  hydrogels  Switching  membranes. Résumé : Pore-filling N-isopropylacrylamide (NIPAAM) polymer hydrogels were successfully grafted onto track-etched polycarbonate (PC) membranes by plasma-induced graft copolymerization. The microstructure and morphology of the PC-g-PNIPAAM membranes were investigated by XPS, SEM, ATR-FTIR, TGA, and water flux experiments. The effective pore sizes were regulated by the volume change of the cross-linked PNIPAAM hydrogels in the temperature range around its lower critical solution temperature (LCST). The PC-g-PNIPAAM membranes demonstrated a fast and reversible valve switching mechanism in a small temperature range. The on−off water flux ratio became more significant with the increase of the monomer concentration. Contact angle results showed that the thermal-responsive gating characteristics of PC-g-PNIPAAM membranes were mainly dependent on the pore size change DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9008666