A variable time delay compensator for multivariable linear processes
A variable time delay compensator based on the Smith predictor is proposed. Finite difference and cinematic techniques are employed for a numerical approximation of the variable delay. The resulting multivariable controller is analyzed for robustness using the structured singular value. The techniqu...
Saved in:
| Published in | Journal of process control Vol. 15; no. 2; pp. 215 - 222 |
|---|---|
| Main Authors | , , |
| Format | Journal Article |
| Language | English |
| Published |
Elsevier Ltd
01.03.2005
|
| Subjects | |
| Online Access | Get full text |
| ISSN | 0959-1524 1873-2771 |
| DOI | 10.1016/j.jprocont.2004.05.005 |
Cover
| Abstract | A variable time delay compensator based on the Smith predictor is proposed. Finite difference and cinematic techniques are employed for a numerical approximation of the variable delay. The resulting multivariable controller is analyzed for robustness using the structured singular value. The technique is demonstrated through two simulated systems: a single-input, single-output numerical example, and a cross-direction paper machine control problem. |
|---|---|
| AbstractList | A variable time delay compensator based on the Smith predictor is proposed. Finite difference and cinematic techniques are employed for a numerical approximation of the variable delay. The resulting multivariable controller is analyzed for robustness using the structured singular value. The technique is demonstrated through two simulated systems: a single-input, single-output numerical example, and a cross-direction paper machine control problem. |
| Author | Doyle, Francis J. Saffer, Daniel R. Castro, Jorge J. |
| Author_xml | – sequence: 1 givenname: Daniel R. surname: Saffer fullname: Saffer, Daniel R. organization: Department of Chemical Engineering, University of Delaware, Newark, DE 19716, USA – sequence: 2 givenname: Jorge J. surname: Castro fullname: Castro, Jorge J. organization: Department of Chemical Engineering, University of Delaware, Newark, DE 19716, USA – sequence: 3 givenname: Francis J. surname: Doyle fullname: Doyle, Francis J. email: doyle@engineering.ucsb.edu organization: Department of Chemical Engineering, University of California, Room 3333, Santa Barbara, CA 93106, USA |
| BookMark | eNqFkMtqwzAQRUVJoUnaXyj-AbsjybYs6KIhfUKgm3YtFGkMMrYVJDWQv69D2i66yWKYzT13mLMgs9GPSMgthYICre-6otsFb_yYCgZQFlAVANUFmdNG8JwJQWdkDrKSOa1YeUUWMXYAwAWr5-Rxle11cHrbY5bcgJnFXh8y44cdjlEnH7J2muGrT-4v2LsRdciOVzFGjNfkstV9xJufvSSfz08f69d88_7ytl5tcsMppFxiw6WoLGes2aJgpQCkxgjJW2qYrhshRI20kQhWyJaZUqPQst1KtEit5ktSn3pN8DEGbNUuuEGHg6Kgji5Up35dqKMLBZWaXEzg_T_QuKSTm3JBu_48_nDCcXpu7zCoaByOBq0LaJKy3p2r-AYpbINu |
| CitedBy_id | crossref_primary_10_3182_20080706_5_KR_1001_02024 crossref_primary_10_1016_j_jfranklin_2015_06_002 crossref_primary_10_1016_j_jprocont_2005_07_006 crossref_primary_10_3182_20080706_5_KR_1001_02608 crossref_primary_10_1016_j_automatica_2010_05_017 crossref_primary_10_1007_s11771_011_0720_8 crossref_primary_10_1016_j_isatra_2023_01_028 crossref_primary_10_1016_j_conengprac_2006_10_002 crossref_primary_10_1049_iet_cta_2010_0088 crossref_primary_10_4028_www_scientific_net_AMM_423_426_2813 crossref_primary_10_1016_j_automatica_2012_11_040 crossref_primary_10_1002_rnc_1470 crossref_primary_10_3182_20110828_6_IT_1002_02899 |
| Cites_doi | 10.1002/aic.690250616 10.1021/ie990059i 10.1002/aic.690320603 10.1177/003754977803100205 10.1021/ie970507r 10.1080/00207178708933912 10.23919/ACC.1984.4788503 10.1016/S1474-6670(17)64231-9 10.1016/0967-0661(95)00151-J 10.1016/0098-1354(90)87051-P 10.1016/0009-2509(89)85133-4 10.1016/S0005-1098(00)00085-6 10.23919/ACC.1983.4788227 10.1080/00207177908922713 |
| ContentType | Journal Article |
| Copyright | 2004 Elsevier Ltd |
| Copyright_xml | – notice: 2004 Elsevier Ltd |
| DBID | AAYXX CITATION |
| DOI | 10.1016/j.jprocont.2004.05.005 |
| DatabaseName | CrossRef |
| DatabaseTitle | CrossRef |
| DatabaseTitleList | |
| DeliveryMethod | fulltext_linktorsrc |
| Discipline | Engineering Computer Science |
| EISSN | 1873-2771 |
| EndPage | 222 |
| ExternalDocumentID | 10_1016_j_jprocont_2004_05_005 S0959152404000617 |
| GroupedDBID | --K --M .DC .~1 0R~ 1B1 1~. 1~5 29L 4.4 457 4G. 5GY 5VS 7-5 71M 8P~ 9JN AACTN AAEDT AAEDW AAIAV AAIKJ AAKOC AALRI AAOAW AAQFI AAQXK AAXUO ABFNM ABFRF ABJNI ABMAC ABNUV ABTAH ABXDB ABYKQ ACDAQ ACGFO ACGFS ACNNM ACRLP ADBBV ADEWK ADEZE ADMUD ADTZH AEBSH AECPX AEFWE AEKER AENEX AFKWA AFTJW AGHFR AGUBO AGYEJ AHHHB AHJVU AHPOS AIEXJ AIKHN AITUG AJBFU AJOXV AKURH ALMA_UNASSIGNED_HOLDINGS AMFUW AMRAJ ASPBG AVWKF AXJTR AZFZN BBWZM BJAXD BKOJK BLXMC CS3 DU5 EBS EFJIC EFLBG EJD ENUVR EO8 EO9 EP2 EP3 F5P FDB FEDTE FGOYB FIRID FNPLU FYGXN G-2 G-Q GBLVA HLY HVGLF HZ~ IHE J1W JJJVA KOM LX7 LY7 M41 MO0 N9A NDZJH O-L O9- OAUVE OZT P-8 P-9 P2P PC. Q38 R2- RIG ROL RPZ SCE SDF SDG SDP SES SET SEW SPC SPCBC SSG SST SSZ T5K UNMZH WUQ XFK ZMT ZY4 ~G- AATTM AAXKI AAYWO AAYXX ABWVN ACLOT ACRPL ACVFH ADCNI ADNMO AEIPS AEUPX AFJKZ AFPUW AGQPQ AIGII AIIUN AKBMS AKRWK AKYEP ANKPU APXCP CITATION EFKBS ~HD |
| ID | FETCH-LOGICAL-c310t-9e83975d3228be72470e1cc793f1c2a687776e189e0d79f2c4ae7a9fb9ede1da3 |
| IEDL.DBID | AIKHN |
| ISSN | 0959-1524 |
| IngestDate | Wed Oct 01 03:49:32 EDT 2025 Thu Apr 24 23:06:40 EDT 2025 Fri Feb 23 02:33:06 EST 2024 |
| IsPeerReviewed | true |
| IsScholarly | true |
| Issue | 2 |
| Keywords | Numerical methods Time-varying system Time delay |
| Language | English |
| License | https://www.elsevier.com/tdm/userlicense/1.0 |
| LinkModel | DirectLink |
| MergedId | FETCHMERGED-LOGICAL-c310t-9e83975d3228be72470e1cc793f1c2a687776e189e0d79f2c4ae7a9fb9ede1da3 |
| PageCount | 8 |
| ParticipantIDs | crossref_primary_10_1016_j_jprocont_2004_05_005 crossref_citationtrail_10_1016_j_jprocont_2004_05_005 elsevier_sciencedirect_doi_10_1016_j_jprocont_2004_05_005 |
| ProviderPackageCode | CITATION AAYXX |
| PublicationCentury | 2000 |
| PublicationDate | 2005-03-01 |
| PublicationDateYYYYMMDD | 2005-03-01 |
| PublicationDate_xml | – month: 03 year: 2005 text: 2005-03-01 day: 01 |
| PublicationDecade | 2000 |
| PublicationTitle | Journal of process control |
| PublicationYear | 2005 |
| Publisher | Elsevier Ltd |
| Publisher_xml | – name: Elsevier Ltd |
| References | J.P. Gerry, E.F. Vogel, T.F. Edgar, Adaptive control of a pilot scale distillation column, in: Proc. American Control Conf., San Francisco, CA, 1983, pp. 819–824 Tan, Lee, Rerdous (BIB6) 1999; 38 Skogestad, Postlethwaite (BIB16) 1996 Majhi, Atherton (BIB5) 2000; 36 Schiesser (BIB12) 1991 Featherstone, Van Antwerp, Braatz (BIB19) 2000 Ogunnaike, Ray (BIB7) 1994 Balas, Doyle, Glover, Packard, Smith (BIB18) 1995 Doyle, Packard, Morari (BIB17) 1989; 44 Ebach, Graser (BIB4) 1995; 3 Tian, Gao (BIB9) 1998; 37 Yamanaka, Uchida, Shimemura (BIB8) 1979; 29 Ogunnaike, Ray (BIB1) 1979; 25 Lakshmanan, Potter (BIB13) 1990; 14 I.-L. Chien, D.E. Seborg, D.A. Mellichamp, Self-tuning controller for systems with unknown or varying time delays, in: Proc. American Control Conf., San Diego, CA, 1984, pp. 905–912 Jerome, Ray (BIB2) 1986; 32 R.G. Wilhelm, M. Fjeld, Control algorithms for cross directional control, in: 5th Int. IFAC/IMEKO Conf. on Instrum. and Autom. in the Paper, Rubber, Plastics, and Polymerization Industries, Antwerp, Belgium, 1983, pp. 163–174 Carber, Hinds (BIB14) 1978; 31 Laughlin, Riveria, Morari (BIB3) 1987; 46 Schiesser, Silebi (BIB15) 1997 Ogunnaike (10.1016/j.jprocont.2004.05.005_BIB7) 1994 Yamanaka (10.1016/j.jprocont.2004.05.005_BIB8) 1979; 29 Schiesser (10.1016/j.jprocont.2004.05.005_BIB12) 1991 Ebach (10.1016/j.jprocont.2004.05.005_BIB4) 1995; 3 10.1016/j.jprocont.2004.05.005_BIB10 10.1016/j.jprocont.2004.05.005_BIB11 Featherstone (10.1016/j.jprocont.2004.05.005_BIB19) 2000 10.1016/j.jprocont.2004.05.005_BIB20 Tan (10.1016/j.jprocont.2004.05.005_BIB6) 1999; 38 Carber (10.1016/j.jprocont.2004.05.005_BIB14) 1978; 31 Lakshmanan (10.1016/j.jprocont.2004.05.005_BIB13) 1990; 14 Schiesser (10.1016/j.jprocont.2004.05.005_BIB15) 1997 Majhi (10.1016/j.jprocont.2004.05.005_BIB5) 2000; 36 Skogestad (10.1016/j.jprocont.2004.05.005_BIB16) 1996 Laughlin (10.1016/j.jprocont.2004.05.005_BIB3) 1987; 46 Ogunnaike (10.1016/j.jprocont.2004.05.005_BIB1) 1979; 25 Jerome (10.1016/j.jprocont.2004.05.005_BIB2) 1986; 32 Tian (10.1016/j.jprocont.2004.05.005_BIB9) 1998; 37 Balas (10.1016/j.jprocont.2004.05.005_BIB18) 1995 Doyle (10.1016/j.jprocont.2004.05.005_BIB17) 1989; 44 |
| References_xml | – reference: R.G. Wilhelm, M. Fjeld, Control algorithms for cross directional control, in: 5th Int. IFAC/IMEKO Conf. on Instrum. and Autom. in the Paper, Rubber, Plastics, and Polymerization Industries, Antwerp, Belgium, 1983, pp. 163–174 – volume: 14 start-page: 945 year: 1990 end-page: 956 ident: BIB13 article-title: Cinematic modeling of dynamics of countercurrent systems publication-title: Comput. Chem. Eng – volume: 37 start-page: 982 year: 1998 end-page: 986 ident: BIB9 article-title: Compensation of dominant and variable delay in process systems publication-title: Ind. Eng. Chem. Res – year: 1995 ident: BIB18 article-title: μ-Analysis and Synthesis Toolbox User's Guide – volume: 46 start-page: 477 year: 1987 end-page: 504 ident: BIB3 article-title: Smith predictor design for robust performance publication-title: Int. J. Control – reference: J.P. Gerry, E.F. Vogel, T.F. Edgar, Adaptive control of a pilot scale distillation column, in: Proc. American Control Conf., San Francisco, CA, 1983, pp. 819–824 – year: 2000 ident: BIB19 article-title: Identification and Control of Sheet and Film Processes – volume: 36 start-page: 1651 year: 2000 end-page: 1658 ident: BIB5 article-title: Obtaining controller parameters for a new Smith predictor using autotuning publication-title: Automatica – volume: 3 start-page: 1467 year: 1995 end-page: 1470 ident: BIB4 article-title: Design of an extended Smith controller with gain adaptation publication-title: Control Eng. Prac – volume: 29 start-page: 489 year: 1979 end-page: 495 ident: BIB8 article-title: Optimal control of systems with time delay publication-title: Int.J. Control – volume: 44 start-page: 1929 year: 1989 end-page: 1947 ident: BIB17 article-title: Robust controller design for a nonlinear CSTR publication-title: Chem. Eng. Sci – year: 1991 ident: BIB12 article-title: The Numerical Method of Lines: Integration of Partial Differential Equations – volume: 31 start-page: 59 year: 1978 end-page: 69 ident: BIB14 article-title: The method of lines and the advection equation publication-title: Simulation – volume: 25 start-page: 1043 year: 1979 ident: BIB1 article-title: Multivariable controller design for linear systems having multiple time delays publication-title: AIChE J – reference: I.-L. Chien, D.E. Seborg, D.A. Mellichamp, Self-tuning controller for systems with unknown or varying time delays, in: Proc. American Control Conf., San Diego, CA, 1984, pp. 905–912 – volume: 32 start-page: 914 year: 1986 end-page: 931 ident: BIB2 article-title: High-performance multivariable control strategies for systems having time delays publication-title: AIChE J – year: 1994 ident: BIB7 article-title: Process Dynamics, Modeling, and Control – volume: 38 start-page: 3438 year: 1999 end-page: 3445 ident: BIB6 article-title: New approach for design and automatic tuning of the Smith predictor controller publication-title: Ind. Eng. Chem. Res – year: 1997 ident: BIB15 article-title: Computational Transport Phenomena: Numerical Methods for the Solution of Transport Problems – year: 1996 ident: BIB16 article-title: Multivariable Feedback Control – year: 1994 ident: 10.1016/j.jprocont.2004.05.005_BIB7 – volume: 25 start-page: 1043 issue: 6 year: 1979 ident: 10.1016/j.jprocont.2004.05.005_BIB1 article-title: Multivariable controller design for linear systems having multiple time delays publication-title: AIChE J doi: 10.1002/aic.690250616 – volume: 38 start-page: 3438 issue: 9 year: 1999 ident: 10.1016/j.jprocont.2004.05.005_BIB6 article-title: New approach for design and automatic tuning of the Smith predictor controller publication-title: Ind. Eng. Chem. Res doi: 10.1021/ie990059i – volume: 32 start-page: 914 issue: 6 year: 1986 ident: 10.1016/j.jprocont.2004.05.005_BIB2 article-title: High-performance multivariable control strategies for systems having time delays publication-title: AIChE J doi: 10.1002/aic.690320603 – volume: 31 start-page: 59 issue: 2 year: 1978 ident: 10.1016/j.jprocont.2004.05.005_BIB14 article-title: The method of lines and the advection equation publication-title: Simulation doi: 10.1177/003754977803100205 – volume: 37 start-page: 982 issue: 3 year: 1998 ident: 10.1016/j.jprocont.2004.05.005_BIB9 article-title: Compensation of dominant and variable delay in process systems publication-title: Ind. Eng. Chem. Res doi: 10.1021/ie970507r – year: 2000 ident: 10.1016/j.jprocont.2004.05.005_BIB19 – volume: 46 start-page: 477 issue: 2 year: 1987 ident: 10.1016/j.jprocont.2004.05.005_BIB3 article-title: Smith predictor design for robust performance publication-title: Int. J. Control doi: 10.1080/00207178708933912 – ident: 10.1016/j.jprocont.2004.05.005_BIB11 doi: 10.23919/ACC.1984.4788503 – ident: 10.1016/j.jprocont.2004.05.005_BIB20 doi: 10.1016/S1474-6670(17)64231-9 – year: 1997 ident: 10.1016/j.jprocont.2004.05.005_BIB15 – year: 1995 ident: 10.1016/j.jprocont.2004.05.005_BIB18 – volume: 3 start-page: 1467 issue: 10 year: 1995 ident: 10.1016/j.jprocont.2004.05.005_BIB4 article-title: Design of an extended Smith controller with gain adaptation publication-title: Control Eng. Prac doi: 10.1016/0967-0661(95)00151-J – volume: 14 start-page: 945 issue: 9 year: 1990 ident: 10.1016/j.jprocont.2004.05.005_BIB13 article-title: Cinematic modeling of dynamics of countercurrent systems publication-title: Comput. Chem. Eng doi: 10.1016/0098-1354(90)87051-P – volume: 44 start-page: 1929 issue: 9 year: 1989 ident: 10.1016/j.jprocont.2004.05.005_BIB17 article-title: Robust controller design for a nonlinear CSTR publication-title: Chem. Eng. Sci doi: 10.1016/0009-2509(89)85133-4 – volume: 36 start-page: 1651 issue: 11 year: 2000 ident: 10.1016/j.jprocont.2004.05.005_BIB5 article-title: Obtaining controller parameters for a new Smith predictor using autotuning publication-title: Automatica doi: 10.1016/S0005-1098(00)00085-6 – ident: 10.1016/j.jprocont.2004.05.005_BIB10 doi: 10.23919/ACC.1983.4788227 – volume: 29 start-page: 489 issue: 3 year: 1979 ident: 10.1016/j.jprocont.2004.05.005_BIB8 article-title: Optimal control of systems with time delay publication-title: Int.J. Control doi: 10.1080/00207177908922713 – year: 1991 ident: 10.1016/j.jprocont.2004.05.005_BIB12 – year: 1996 ident: 10.1016/j.jprocont.2004.05.005_BIB16 |
| SSID | ssj0003726 |
| Score | 1.8531424 |
| Snippet | A variable time delay compensator based on the Smith predictor is proposed. Finite difference and cinematic techniques are employed for a numerical... |
| SourceID | crossref elsevier |
| SourceType | Enrichment Source Index Database Publisher |
| StartPage | 215 |
| SubjectTerms | Numerical methods Time delay Time-varying system |
| Title | A variable time delay compensator for multivariable linear processes |
| URI | https://dx.doi.org/10.1016/j.jprocont.2004.05.005 |
| Volume | 15 |
| hasFullText | 1 |
| inHoldings | 1 |
| isFullTextHit | |
| isPrint | |
| journalDatabaseRights | – providerCode: PRVESC databaseName: Elsevier Science Direct customDbUrl: eissn: 1873-2771 dateEnd: 99991231 omitProxy: true ssIdentifier: ssj0003726 issn: 0959-1524 databaseCode: ACRLP dateStart: 19950101 isFulltext: true titleUrlDefault: https://www.sciencedirect.com providerName: Elsevier – providerCode: PRVESC databaseName: Elsevier SD Freedom Collection Journals [SCFCJ] customDbUrl: eissn: 1873-2771 dateEnd: 99991231 omitProxy: true ssIdentifier: ssj0003726 issn: 0959-1524 databaseCode: AIKHN dateStart: 19950101 isFulltext: true titleUrlDefault: https://www.sciencedirect.com providerName: Elsevier – providerCode: PRVESC databaseName: ScienceDirect (Elsevier) customDbUrl: eissn: 1873-2771 dateEnd: 99991231 omitProxy: true ssIdentifier: ssj0003726 issn: 0959-1524 databaseCode: .~1 dateStart: 19950101 isFulltext: true titleUrlDefault: https://www.sciencedirect.com providerName: Elsevier – providerCode: PRVLSH databaseName: Elsevier Journals customDbUrl: mediaType: online eissn: 1873-2771 dateEnd: 99991231 omitProxy: true ssIdentifier: ssj0003726 issn: 0959-1524 databaseCode: AKRWK dateStart: 19910101 isFulltext: true providerName: Library Specific Holdings |
| link | http://utb.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwpV1LSwMxEB76uOjBR1Wsj5KD1-02-8rmWKqlKvSihd6WbHYWWqQttQpe_O1msrulgtCD1yUDyySZ-SZ8Mx_AXZiqNNOe73iohBMgakcKXznoy0goHw2GtwTZcTSaBE_TcFqDQdULQ7TKMvYXMd1G6_KLW3rTXc1m7gu9YJnsE9AxpERch6bJP3HcgGb_8Xk03gZkX1jVNfviRQY7jcLz7pwSxXJhaZWBHeJJSnZ_5aidvDM8gaMSMLJ-8U-nUMNFC44rMQZW3s0WHO5MFjyD-z77NFUw9UUxko9nNAzyixGB3NStVGgzg1aZpRNuFxLiVGu2KnoH8P0cJsOH18HIKQUTHG1Q2saRaOCOCDNzSeMUhReIHnKtzRXMufZURLP_IuSxxF4mZO7pQKFQMk8lZsgz5V9AY7Fc4CUwIbQXoyl2zCYHPOVmteB5FJO7I8VFG8LKRYkup4mTqMVbUtHG5knlWpK6DJJemBjXtsHd2q2KeRp7LWS1A8mvk5GYoL_H9uofttdwYMe0Wr7ZDTQ26w-8NQBkk3ag3v3mnfKY_QDTw9xC |
| linkProvider | Elsevier |
| linkToHtml | http://utb.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwpV1NT8JAEJ0gHtSDH6gRP_fgtZS22257JChBRS5Cwq3ZbocEYgpBNPHib3dn2yImJhy8NjtJM7s782bzZh7ArZ_IJFWuZ7kohcURlRUJT1roRYGQHmoMbwiy_aA75I8jf1SBdtkLQ7TKIvbnMd1E6-KLXXjTnk8m9gu9YOnsw-kYUiLegm3uu4IqsMbXD8_DE0Zzzbx30fK1NuFpY0ppYpYZUiU3IzxJx-6vDLWWdTqHsF_ARdbK_-gIKpjV4KCUYmDFzazB3tpcwWO4a7EPXQNTVxQj8XhGoyA_GdHHddVKZTbTWJUZMuFqIeFNuWDzvHMA305g2LkftLtWIZdgKY3RllaEGuwIP9VXNExQuFw00VFKX8Cxo1wZ0OS_AJ0wwmYqorGruEQho3ESYYpOKr1TqGazDM-ACaHcEHWpo7eYO4mjVwtnHITk7EA6og5-6aJYFbPESdLiNS5JY9O4dC0JXfK46cfatXWwV3bzfJrGRouo3IH417mIdcjfYHv-D9sb2OkOnntx76H_dAG7ZmCrYZ5dQnW5eMcrDUWWybU5at-oz90K |
| openUrl | ctx_ver=Z39.88-2004&ctx_enc=info%3Aofi%2Fenc%3AUTF-8&rfr_id=info%3Asid%2Fsummon.serialssolutions.com&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=A+variable+time+delay+compensator+for+multivariable+linear+processes&rft.jtitle=Journal+of+process+control&rft.au=Saffer%2C+Daniel+R.&rft.au=Castro%2C+Jorge+J.&rft.au=Doyle%2C+Francis+J.&rft.date=2005-03-01&rft.issn=0959-1524&rft.volume=15&rft.issue=2&rft.spage=215&rft.epage=222&rft_id=info:doi/10.1016%2Fj.jprocont.2004.05.005&rft.externalDBID=n%2Fa&rft.externalDocID=10_1016_j_jprocont_2004_05_005 |
| thumbnail_l | http://covers-cdn.summon.serialssolutions.com/index.aspx?isbn=/lc.gif&issn=0959-1524&client=summon |
| thumbnail_m | http://covers-cdn.summon.serialssolutions.com/index.aspx?isbn=/mc.gif&issn=0959-1524&client=summon |
| thumbnail_s | http://covers-cdn.summon.serialssolutions.com/index.aspx?isbn=/sc.gif&issn=0959-1524&client=summon |