{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/29638"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/29638","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Hierarchical supervisory control of complex Petri nets","abstract":"Large, complex systems are prone to the phenomenon of livelocks. Once a system enters a livelocked-state, there is at least one activity of the modeled system that cannot be executed from all subsequent states of the system. This phenomenon is common to many operating systems where some process enters into a state of suspended animation for all perpetuity, and the user is left with no other option than to forcibly kill the suspended job, or reboot the machine. This thesis is about finding supervisory control policies that enforce livelock-freedom in large complex systems that are modeled using Petri nets. The supervisory policy, when it exists, prevents the occurrence of certain events (i.e. activities) at specific states in such a way that the supervised system is livelock free. A hierarchical approach is used to find a supervisory policy for petri nets. This theory finds application for concurrent systems like computer operating systems which are complex to analyze. The complex system is (recursively) represented as the combination of two smaller systems. Under favorable conditions identified in this thesis, local supervisory policies that enforces livelock-freedom in each of the smaller systems will suffice to enforce livelock-freedom in the larger system.","abstract_html":"Large, complex systems are prone to the phenomenon of livelocks. Once a system enters a livelocked-state, there is at least one activity of the modeled system that cannot be executed from all subsequent states of the system. This phenomenon is common to many operating systems where some process enters into a state of suspended animation for all perpetuity, and the user is left with no other option than to forcibly kill the suspended job, or reboot the machine. This thesis is about finding supervisory control policies that enforce livelock-freedom in large complex systems that are modeled using Petri nets. The supervisory policy, when it exists, prevents the occurrence of certain events (i.e. activities) at specific states in such a way that the supervised system is livelock free. A hierarchical approach is used to find a supervisory policy for petri nets. This theory finds application for concurrent systems like computer operating systems which are complex to analyze. The complex system is (recursively) represented as the combination of two smaller systems. Under favorable conditions identified in this thesis, local supervisory policies that enforces livelock-freedom in each of the smaller systems will suffice to enforce livelock-freedom in the larger system.","abstract_has_math":false,"creators":["Somnath, Nisha"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Aerospace Engineering","degree_department":null,"school":null,"contributors":["Sreenivas, Ramavarapu S."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012-02-06T20:08:11Z","date_published":"2012-02-06T20:08:11Z","updated_at":"2026-07-22T22:25:27Z","subjects":["Petri nets","Supervisory control","Concurrent systems"],"languages":["en"],"rights":["Copyright 2011 Nisha Somnath"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/29638","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Sreenivas, Ramavarapu S."]},{"key":"dc:creator","label":"Author","values":["Somnath, Nisha"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2012-02-06T20:08:11Z","2011-12"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aerospace Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Petri nets","Supervisory control","Concurrent systems"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2011 Nisha Somnath"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/29638"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Large, complex systems are prone to the phenomenon of livelocks. Once a system enters a livelocked-state, there is at least one activity of the modeled system that cannot be executed from all subsequent states of the system. This phenomenon is common to many operating systems where some process enters into a state of suspended animation for all perpetuity, and the user is left with no other option than to forcibly kill the suspended job, or reboot the machine. This thesis is about finding supervisory control policies that enforce livelock-freedom in large complex systems that are modeled using Petri nets. The supervisory policy, when it exists, prevents the occurrence of certain events (i.e. activities) at specific states in such a way that the supervised system is livelock free. A hierarchical approach is used to find a supervisory policy for petri nets. This theory finds application for concurrent systems like computer operating systems which are complex to analyze. The complex system is (recursively) represented as the combination of two smaller systems. Under favorable conditions identified in this thesis, local supervisory policies that enforces livelock-freedom in each of the smaller systems will suffice to enforce livelock-freedom in the larger system.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2011-12-06T22:27:20Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 thesis-final.tex: 84516 bytes, checksum: c1b09149b828271cfae29ada084351dc (MD5) Somnath_Nisha.pdf: 502200 bytes, checksum: 42970575cfa93b99e111f4baccfb4f66 (MD5)","Made available in DSpace on 2012-02-06T20:08:11Z (GMT). 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This thesis is about finding supervisory control policies that enforce livelock-freedom in large complex systems that are modeled using Petri nets. The supervisory policy, when it exists, prevents the occurrence of certain events (i.e. activities) at specific states in such a way that the supervised system is livelock free. A hierarchical approach is used to find a supervisory policy for petri nets. This theory finds application for concurrent systems like computer operating systems which are complex to analyze. The complex system is (recursively) represented as the combination of two smaller systems. Under favorable conditions identified in this thesis, local supervisory policies that enforces livelock-freedom in each of the smaller systems will suffice to enforce livelock-freedom in the larger system.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2011-12-06T22:27:20Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 thesis-final.tex: 84516 bytes, checksum: c1b09149b828271cfae29ada084351dc (MD5) Somnath_Nisha.pdf: 502200 bytes, checksum: 42970575cfa93b99e111f4baccfb4f66 (MD5)","Made available in DSpace on 2012-02-06T20:08:11Z (GMT). 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