{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/107854"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/107854","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Inference of electromagnetic system behavior in the presence of variability","abstract":"This thesis contributes to and advances the state-of-the-art of the analysis of stochastic electromagnetic-circuit systems by applying novel statistical inference and generative modeling techniques to the extraction of statistical models of system responses. Machine learning based and physics based techniques are introduced to address the limitations of existing methods by incorporating dimensionality reduction into the model training procedure, enabling the enforcement of certain physical constraints, making the modeling procedure more flexible by accepting additional data to capture dependency, and taking advantage of universal statistics to reduce the sample requirement. Specifically, for the first time, a variational autoencoder based method is used for the generative modeling of high-dimensional S-parameters data. The generation accuracy is shown to be superior to that of existing methods. The passive variational autoencoder, a variational autoencoder with modified decoder architecture, is introduced to enforce physical constraints like passivity. The generated S-parameters are shown to be physically consistent. The generation accuracy and efficiency of the proposed method are assessed through comparison to those of existing methods. When a system is decomposed into multiple subsystems, the dependency between responses of subsystems needs to be captured but is often neglected. A conditional variational autoencoder is introduced for the capturing of such dependency. Additional control variables are used to account for the randomness external to a subsystem. The conditional variational autoencoder based generative model demonstrates an advantage in terms of generation accuracy as compared to its standard version, which ignores the dependency between subsystems. The random coupling model is a physics based generative model applicable to electromagnetic enclosures under wave chaos condition. The low-frequency limit of the random coupling model based generative model is shown to be assessed by computing the random projection Kolmogorov-Smirnov statistics, and the low-frequency limit is demonstrated to be lower than the rule-of-thumb estimate used in past works.","abstract_html":"This thesis contributes to and advances the state-of-the-art of the analysis of stochastic electromagnetic-circuit systems by applying novel statistical inference and generative modeling techniques to the extraction of statistical models of system responses. Machine learning based and physics based techniques are introduced to address the limitations of existing methods by incorporating dimensionality reduction into the model training procedure, enabling the enforcement of certain physical constraints, making the modeling procedure more flexible by accepting additional data to capture dependency, and taking advantage of universal statistics to reduce the sample requirement. Specifically, for the first time, a variational autoencoder based method is used for the generative modeling of high-dimensional S-parameters data. The generation accuracy is shown to be superior to that of existing methods. The passive variational autoencoder, a variational autoencoder with modified decoder architecture, is introduced to enforce physical constraints like passivity. The generated S-parameters are shown to be physically consistent. The generation accuracy and efficiency of the proposed method are assessed through comparison to those of existing methods. When a system is decomposed into multiple subsystems, the dependency between responses of subsystems needs to be captured but is often neglected. A conditional variational autoencoder is introduced for the capturing of such dependency. Additional control variables are used to account for the randomness external to a subsystem. The conditional variational autoencoder based generative model demonstrates an advantage in terms of generation accuracy as compared to its standard version, which ignores the dependency between subsystems. The random coupling model is a physics based generative model applicable to electromagnetic enclosures under wave chaos condition. The low-frequency limit of the random coupling model based generative model is shown to be assessed by computing the random projection Kolmogorov-Smirnov statistics, and the low-frequency limit is demonstrated to be lower than the rule-of-thumb estimate used in past works.","abstract_has_math":false,"creators":["Ma, Xiao"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Cangellaris, Andreas","Rosenbaum, Elyse","Raginsky, Maxim","Schutt-Aine, Jose"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-08-26T21:54:04Z","date_published":"2020-08-26T21:54:04Z","updated_at":"2026-07-22T22:24:47Z","subjects":["Stochastic electromagnetic-circuit analysis","Statistical inference","Generative modeling","S-parameters","Variational autoencoder","Physical constraints","Passivity","Dependency between subsystems","Conditional variational autoencoder","Universal statistics","Random coupling model","Wave chaos"],"languages":["en"],"rights":["Copyright 2020 Xiao Ma"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/107854","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Cangellaris, Andreas","Rosenbaum, Elyse","Raginsky, Maxim","Schutt-Aine, Jose"]},{"key":"dc:creator","label":"Author","values":["Ma, Xiao"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020-08-26T21:54:04Z","2020-02-28","2020-05"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"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":["Stochastic electromagnetic-circuit analysis","Statistical inference","Generative modeling","S-parameters","Variational autoencoder","Physical constraints","Passivity","Dependency between subsystems","Conditional variational autoencoder","Universal statistics","Random coupling model","Wave chaos"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2020 Xiao Ma"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/107854"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["This thesis contributes to and advances the state-of-the-art of the analysis of stochastic electromagnetic-circuit systems by applying novel statistical inference and generative modeling techniques to the extraction of statistical models of system responses. Machine learning based and physics based techniques are introduced to address the limitations of existing methods by incorporating dimensionality reduction into the model training procedure, enabling the enforcement of certain physical constraints, making the modeling procedure more flexible by accepting additional data to capture dependency, and taking advantage of universal statistics to reduce the sample requirement. Specifically, for the first time, a variational autoencoder based method is used for the generative modeling of high-dimensional S-parameters data. The generation accuracy is shown to be superior to that of existing methods. The passive variational autoencoder, a variational autoencoder with modified decoder architecture, is introduced to enforce physical constraints like passivity. The generated S-parameters are shown to be physically consistent. The generation accuracy and efficiency of the proposed method are assessed through comparison to those of existing methods. When a system is decomposed into multiple subsystems, the dependency between responses of subsystems needs to be captured but is often neglected. A conditional variational autoencoder is introduced for the capturing of such dependency. Additional control variables are used to account for the randomness external to a subsystem. The conditional variational autoencoder based generative model demonstrates an advantage in terms of generation accuracy as compared to its standard version, which ignores the dependency between subsystems. The random coupling model is a physics based generative model applicable to electromagnetic enclosures under wave chaos condition. The low-frequency limit of the random coupling model based generative model is shown to be assessed by computing the random projection Kolmogorov-Smirnov statistics, and the low-frequency limit is demonstrated to be lower than the rule-of-thumb estimate used in past works.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2020-08-25 without embargo terms","The student, Xiao Ma, accepted the attached license on 2020-02-28 at 09:57.","The student, Xiao Ma, submitted this Dissertation for approval on 2020-02-28 at 10:30.","This Dissertation was approved for publication on 2020-02-28 at 15:26.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14880 on 2020-08-25 at 17:04:42","Made available in DSpace on 2020-08-26T21:54:04Z (GMT). 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Machine learning based and physics based techniques are introduced to address the limitations of existing methods by incorporating dimensionality reduction into the model training procedure, enabling the enforcement of certain physical constraints, making the modeling procedure more flexible by accepting additional data to capture dependency, and taking advantage of universal statistics to reduce the sample requirement. Specifically, for the first time, a variational autoencoder based method is used for the generative modeling of high-dimensional S-parameters data. The generation accuracy is shown to be superior to that of existing methods. The passive variational autoencoder, a variational autoencoder with modified decoder architecture, is introduced to enforce physical constraints like passivity. The generated S-parameters are shown to be physically consistent. The generation accuracy and efficiency of the proposed method are assessed through comparison to those of existing methods. When a system is decomposed into multiple subsystems, the dependency between responses of subsystems needs to be captured but is often neglected. A conditional variational autoencoder is introduced for the capturing of such dependency. Additional control variables are used to account for the randomness external to a subsystem. The conditional variational autoencoder based generative model demonstrates an advantage in terms of generation accuracy as compared to its standard version, which ignores the dependency between subsystems. The random coupling model is a physics based generative model applicable to electromagnetic enclosures under wave chaos condition. The low-frequency limit of the random coupling model based generative model is shown to be assessed by computing the random projection Kolmogorov-Smirnov statistics, and the low-frequency limit is demonstrated to be lower than the rule-of-thumb estimate used in past works.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2020-08-25 without embargo terms","The student, Xiao Ma, accepted the attached license on 2020-02-28 at 09:57.","The student, Xiao Ma, submitted this Dissertation for approval on 2020-02-28 at 10:30.","This Dissertation was approved for publication on 2020-02-28 at 15:26.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14880 on 2020-08-25 at 17:04:42","Made available in DSpace on 2020-08-26T21:54:04Z (GMT). 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