SCI和EI收录∣中国化工学会会刊

›› 2009, Vol. 17 ›› Issue (3): 437-444.

• PROCESS SYSTEMS ENGINEERING • Previous Articles     Next Articles

Modeling of Isomerization of C8 Aromatics by Online Least Squares Support Vector Machine

LI Lijuan1,2, SU Hongye2, CHU Jian2   

  1. 1. College of Automation and Electrical Engineering, Nanjing University of Technology, Nanjing 210009, China;
    2. State Key Lab. of Industrial Control Technology, Institute of Cyber-systems and Control, Zhejiang University, Hangzhou 310027, China
  • Received:2008-04-30 Revised:2009-03-20 Online:2009-06-28 Published:2009-06-28
  • Supported by:
    Supported by the National Creative Research Groups Science Foundation of China (60721062);the National Basic Research Program of China (2007CB714000)

Modeling of Isomerization of C8 Aromatics by Online Least Squares Support Vector Machine

李丽娟1,2, 苏宏业2, 褚建2   

  1. 1. College of Automation and Electrical Engineering, Nanjing University of Technology, Nanjing 210009, China;
    2. State Key Lab. of Industrial Control Technology, Institute of Cyber-systems and Control, Zhejiang University, Hangzhou 310027, China
  • 通讯作者: LI Lijuan,E-mail:ljli@njut.edu.cn
  • 基金资助:
    Supported by the National Creative Research Groups Science Foundation of China (60721062);the National Basic Research Program of China (2007CB714000)

Abstract: The least squares support vector regression (LS-SVR) is usually used for the modeling of single output system, but it is not well suitable for the actual multi-input-multi-output system. The paper aims at the modeling of multi-output systems by LS-SVR. The multi-output LS-SVR is derived in detail. To avoid the inversion of large matrix, the recursive algorithm of the parameters is given, which makes the online algorithm of LS-SVR practical. Since the computing time increases with the number of training samples, the sparseness is studied based on the projection of online LS-SVR. The residual of projection less than a threshold is omitted, so that a lot of samples are kept out of the training set and the sparseness is obtained. The standard LS-SVR, nonsparse online LS-SVR and sparse online LS-SVR with different threshold are used for modeling the isomerization of C8 aromatics. The root-mean-square-error (RMSE), number of support vectors and running time of three algorithms are compared and the result indicates that the performance of sparse online LS-SVR is more favorable.

Key words: least squares support vector machine, multi-variable, online, sparseness, isomerization

摘要: The least squares support vector regression (LS-SVR) is usually used for the modeling of single output system, but it is not well suitable for the actual multi-input-multi-output system. The paper aims at the modeling of multi-output systems by LS-SVR. The multi-output LS-SVR is derived in detail. To avoid the inversion of large matrix, the recursive algorithm of the parameters is given, which makes the online algorithm of LS-SVR practical. Since the computing time increases with the number of training samples, the sparseness is studied based on the projection of online LS-SVR. The residual of projection less than a threshold is omitted, so that a lot of samples are kept out of the training set and the sparseness is obtained. The standard LS-SVR, nonsparse online LS-SVR and sparse online LS-SVR with different threshold are used for modeling the isomerization of C8 aromatics. The root-mean-square-error (RMSE), number of support vectors and running time of three algorithms are compared and the result indicates that the performance of sparse online LS-SVR is more favorable.

关键词: least squares support vector machine, multi-variable, online, sparseness, isomerization