911½ñÈÕºÚÁÏ

Search or filter publications

Search publications Search

Filter by type:

Filter by publication type

• Book
• Book chapter
• Conference paper
• Journal article
• Patent
• Report
• Software

Filter by year:

Filter from 202020192018201720162015201420132012201120102009200820072006200520042003200220012000199919981997199619951994199319921991199019891988198719861985198419831982198119801979197819771976 to Filter to 202020192018201720162015201420132012201120102009200820072006200520042003200220012000199919981997199619951994199319921991199019891988198719861985198419831982198119801979197819771976

---

Search results

• Conference paper
  Choudhury MAAS, Kariwala V, Shah SL, Douke H, Takada H, Thornhill NFet al., 2005,
  , Pages: 81-86, ISSN: 1474-6670

  Stiction is a common problem in the widely used spring-diaphragm type control valves in the process industry. Several methods are available for detecting stiction in control valves. After detection of stiction, a test is required to confirm that the valve in question is indeed suffering from stiction. This paper presents a simple closed loop test, based on changing only the controller gain, for confirming the presence of stiction. The method does not require that the loop be put in manual, which can otherwise upset the plant. The usefulness of this test is demonstrated through simulation studies and an industrial application. Copyright © 2005 IFAC.

  • Abstract
  • Cite
  • Citations: 25
• Journal article
  Anaparthi KK, Chaudhuri B, Thornhill NF, Pal BCet al., 2005,

  Coherency identification in power systems through principal component analysis

  , IEEE Transactions on Power Systems, Vol: 20, Pages: 1658-1660, ISSN: 0885-8950
  • Cite
• Journal article
  Choudhury MAAS, Shah SL, Thornhill NF, 2004,
  , AUTOMATICA, Vol: 40, Pages: 1719-1728, ISSN: 0005-1098
  • Cite
  • Citations: 185
• Journal article
  Thornhill NF, Choudhury MAAS, Shah SL, 2004,
  , JOURNAL OF PROCESS CONTROL, Vol: 14, Pages: 389-398, ISSN: 0959-1524
  • Cite
  • Citations: 45
• Journal article
  Law VJ, Kenyon AJ, Thornhill NF, Pagliarani A, Lea L, Watkins Met al., 2004,
  , MEASUREMENT SCIENCE AND TECHNOLOGY, Vol: 15, Pages: 231-236, ISSN: 0957-0233
  • Cite
  • Citations: 6
• Conference paper
  Bauer M, Thornhill NF, Meaburn A, 2004,

  Specifying the directionality of fault propagation paths using transfer entropy

  , 7th International Symposium on Dynamics and Control of Process Systems (DYCOPS 7)

  In continuous chemical processes, variations of process variables usually travel along propagation paths in the direction of flow. The aim of this study was to find a data-driven method for identifying the direction of variation propagation using historical process data. Transfer entropy is a recently proposed method based on the probability density function (PDF) that measures directionality of variation with respect to time. An industrial case study illustrates the method which detects the influence of a temperature controller on downstream temperature measurements. A reversal of directionality was noted during a disturbance and a physical explanation offered.

  • Abstract
  • Cite
• Journal article
  Thornhill NF, Cox JW, Paulonis MA, 2003,
  , CONTROL ENGINEERING PRACTICE, Vol: 11, Pages: 1481-1490, ISSN: 0967-0661
  • Cite
  • Citations: 107
• Journal article
  Law VJ, Thornhill NF, Kenyon AJ, Paglirani A, Lee K, Watkins M, Lea Let al., 2003,
  , JOURNAL OF PHYSICS D-APPLIED PHYSICS, Vol: 36, Pages: 2146-2151, ISSN: 0022-3727
  • Cite
  • Citations: 2
• Journal article
  Thornhill NF, Huang B, Shah SL, 2003,
  , INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Vol: 17, Pages: 709-727, ISSN: 0890-6327
  • Cite
  • Citations: 20
• Journal article
  Thornhill NF, Huang B, Zhang H, 2003,
  , JOURNAL OF PROCESS CONTROL, Vol: 13, Pages: 91-100, ISSN: 0959-1524
  • Cite
  • Citations: 166
• Journal article
  Apelt TA, Asprey SP, Thornhill NF, 2002,
  , MINERALS ENGINEERING, Vol: 15, Pages: 1043-1053, ISSN: 0892-6875
  • Cite
  • Citations: 22
• Journal article
  Apelt TA, Asprey SP, Thornhill NF, 2002,
  , MINERALS ENGINEERING, Vol: 15, Pages: 1055-1071, ISSN: 0892-6875
  • Cite
  • Citations: 8
• Journal article
  Thornhill NF, Shah SL, Huang B, Vishnubhotla Aet al., 2002,
  , CONTROL ENGINEERING PRACTICE, Vol: 10, Pages: 833-846, ISSN: 0967-0661
  • Cite
  • Citations: 109
• Conference paper
  Wang M, Thornhill NF, Huang B, 2002,
  , Pages: 319-324, ISSN: 1474-6670

  This paper proposes a new closed-loop identification scheme for a single-input-single-output control loop. It is based upon a quantizer inserted into the feedback path. The quantizer can be used to generate an equivalent persistently exciting signal with which the well known two-stage and/or two-step method can be used directly. Simulation examples and an experimental demonstration are used to illustrate the proposed scheme.

  • Abstract
  • Cite
  • Citations: 1
• Conference paper
  Dobson JP, Thornhill NF, 2002,

  Analysis of plant-wide disturbances using conditional entropy

  , IEEE International Conference on Control Applications, Publisher: IEEE, Pages: 687-688

  Plant-wide disturbances in chemical plants have an impact on product quality and running costs, thus there is a need for automated diagnosis of the root cause. This short paper reports work in progress and preliminary results from a novel signal processing application using conditional entropy. It analyses measurements from normal process operations in a chemical plant to determine cause and effect relationships. The method suggests which measurement is the root cause of a plant-wide disturbance and, additionally, maps the physical structure of the plant.

  • Abstract
  • Cite
• Conference paper
  Thornhill NF, Xia C, Howell J, Cox J, Paulonis Met al., 2002,
  , Pages: 399-404, ISSN: 1474-6670

  Plant-wide disturbances can have an impact on product quality and running costs. Thus there is a motivation for automated detection of a plant-wide disturbance and for diagnosis of the root cause. In this article, data-driven techniques are used to analyze plant-wide disturbances caused, for instance, by limit cycle oscillation in a control loop. The control loops participating in the disturbance are detected and displayed on a process schematic. Other numerical signatures derived from the data trends are utilized for the diagnosis of the root cause. The outcome is a visual display that integrates process understanding and data-driven analysis.

  • Abstract
  • Cite
  • Citations: 11
• Journal article
  Tan CC, Thornhill NF, Belchamber RM, 2002,
  , TRANSACTIONS OF THE INSTITUTE OF MEASUREMENT AND CONTROL, Vol: 24, Pages: 333-353, ISSN: 0142-3312
  • Cite
  • Citations: 6
• Journal article
  Law VJ, Kenyon AJ, Thornhill NF, Seeds AJ, Batty Iet al., 2001,
  , JOURNAL OF PHYSICS D-APPLIED PHYSICS, Vol: 34, Pages: 2726-2733, ISSN: 0022-3727
  • Cite
  • Citations: 15
• Journal article
  Apelt TA, Asprey SP, Thornhill NF, 2001,
  , MINERALS ENGINEERING, Vol: 14, Pages: 575-591, ISSN: 0892-6875
  • Cite
  • Citations: 31
• Conference paper
  Wang M, Saleem S, Thornhill NF, 2001,

  Time series reconstruction from quantized measurements

  , University of Texas at Austin, Chemical Process Control VI (CPC6), Publisher: CACHE Corporation, Pages: 448-452
  • Cite

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.