{ "129385-21862604": { "datetime_modified":"20241222T084849", "datetime_start":"20250114T160000", "datetime_end":"20250114T170000", "has_end_time":1, "date_start":"2025-01-14", "date_end":"2025-01-14", "time_start":"16:00:00", "time_end":"17:00:00", "time_zone":"America\/Detroit", "event_title":"Colloquium Seminar: Analysis and Design of High Dimensional Sampling for Scientific Computing", "occurrence_title":"", "combined_title":"Colloquium Seminar: Analysis and Design of High Dimensional Sampling for Scientific Computing: Yifan Chen (Courant Institute, NYU)", "event_subtitle":"Yifan Chen (Courant Institute, NYU)", "event_type":"Workshop \/ Seminar", "event_type_id":"21", "description":"Sampling from probability distributions is a fundamental challenge in physics and data science. State-of-the-art methods often rely on building efficient dynamics for probability measures. This talk examines the analysis and design of such dynamics, drawing insights from and targeting applications in high-dimensional scientific computing. \r\n\r\nIn the first part, we uncover and analyze a novel 'delocalization of bias' phenomenon in MCMC with Langevin dynamics. While sampling bias increases with dimensionality in full coordinates, individual coordinates can exhibit nearly dimension-independent behavior. This finding suggests that the curse of dimensionality in sampling may be mitigated at the level of low-dimensional marginals. In the second part, we propose a generative diffusion dynamics design for probabilistic forecasting, focusing on benchmark applications in stochastically forced Navier-Stokes equations. We prove that a specific design of diffusion coefficients minimizes novel statistical errors at the level of path measures and yields F\u00f6llmer processes, which also offer a Bayesian interpretation of the optimal design. We conclude with a real-data scientific application in black hole imaging, where we combine generative diffusion dynamics with MCMC for rigorous posterior sampling. Overall, the talk demonstrates how mathematical understanding and methodological design of high-dimensional sampling dynamics can synergize with insights and applications in scientific computing.", "occurrence_notes":null, "guid":"129385-21862604@events.umich.edu", "permalink":"http:\/\/events.umich.edu\/event\/129385", "building_id":"1000166", "building_name":"East Hall", "campus_maps_id":"53", "room":"1360", "location_name":"East Hall", "has_livestream":0, "cost":"", "tags":["Mathematics"], "website":"", "sponsors":[ { "group_name":"Colloquium Series - Department of Mathematics", "group_id":"4884", "website":"" }, { "group_name":"Department of Mathematics", "group_id":"3791", "website":"" } ], "image_url":"", "styled_images":{ "event_thumb":"", "event_large":"", "event_large_2x":"", "event_large_lightbox":"", "group_thumb":"", "group_thumb_square":"", "group_large":"", "group_large_lightbox":"", "event_large_crop":"", "event_list":"", "event_list_2x":"", "event_grid":"", "event_grid_2x":"", "event_feature_large":"", "event_feature_thumb":"" }, "occurrence_count":1, "first_occurrence":21862604 } , "130486-21866105": { "datetime_modified":"20250106T151154", "datetime_start":"20250114T160000", "datetime_end":"20250114T180000", "has_end_time":1, "date_start":"2025-01-14", "date_end":"2025-01-14", "time_start":"16:00:00", "time_end":"18:00:00", "time_zone":"America\/Detroit", "event_title":"DAAS Africa Workshop", "occurrence_title":"", "combined_title":"DAAS Africa Workshop: Waiting for Valdez with Teddy Mattera, South African Filmmaker", "event_subtitle":"Waiting for Valdez with Teddy Mattera, South African Filmmaker", "event_type":"Film Screening", "event_type_id":"11", "description":"Please join us for a special screening of \"Waiting for Valdez\" a film by South African filmmaker Teddy Mattera. \r\nWaiting for Valdez\" tells the story of a young boy named Sharky living in apartheid-era Johannesburg, who is desperately trying to see the movie \"Valdez is Coming\" starring Burt Lancaster, but due to his circumstances under segregation, he can only experience the film through secondhand accounts from friends, ultimately missing the conclusion due to his grandmother's illness, providing a poignant portrait of the everyday life under the oppressive regime; the film uses the \"Valdez is Coming\" narrative as a symbol of hope and resistance against injustice.\r\nMattera will be present via zoom to discuss the film following the screening.", "occurrence_notes":"https:\/\/umich.zoom.us\/j\/96450047609", "guid":"130486-21866105@events.umich.edu", "permalink":"http:\/\/events.umich.edu\/event\/130486", "building_id":"1000175", "building_name":"Haven Hall", "campus_maps_id":"542", "room":"4701 Haven Hall (DAAS Conference Room)", "location_name":"Haven Hall", "has_livestream":0, "cost":"", "tags":["South Africa","film screening","film","daas","African Studies Center","African Studies","african diaspora","africa"], "website":"", "sponsors":[ { "group_name":"Department of Afroamerican and African Studies", "group_id":"1144", "website":"http:\/\/www.lsa.umich.edu\/daas\/" }, { "group_name":"African Studies Center", "group_id":"3187", "website":"http:\/\/www.ii.umich.edu\/asc\/" } ], "image_url":"https:\/\/events.umich.edu\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "styled_images":{ "event_thumb":"https:\/\/events.umich.edu\/media\/cache\/event_thumb\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "event_large":"https:\/\/events.umich.edu\/media\/cache\/event_large\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "event_large_2x":"https:\/\/events.umich.edu\/media\/cache\/event_large_2x\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "event_large_lightbox":"https:\/\/events.umich.edu\/media\/cache\/event_large_lightbox\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "group_thumb":"https:\/\/events.umich.edu\/media\/cache\/resolve\/group_thumb\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "group_thumb_square":"https:\/\/events.umich.edu\/media\/cache\/resolve\/group_thumb_square\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "group_large":"https:\/\/events.umich.edu\/media\/cache\/resolve\/group_large\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "group_large_lightbox":"https:\/\/events.umich.edu\/media\/cache\/resolve\/group_large_lightbox\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "event_large_crop":"https:\/\/events.umich.edu\/media\/cache\/resolve\/event_large_crop\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "event_list":"https:\/\/events.umich.edu\/media\/cache\/resolve\/event_list\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "event_list_2x":"https:\/\/events.umich.edu\/media\/cache\/event_list_2x\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "event_grid":"https:\/\/events.umich.edu\/media\/cache\/event_grid\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "event_grid_2x":"https:\/\/events.umich.edu\/media\/cache\/resolve\/event_grid_2x\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "event_feature_large":"https:\/\/events.umich.edu\/media\/cache\/resolve\/event_feature_large\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg", "event_feature_thumb":"https:\/\/events.umich.edu\/media\/cache\/resolve\/event_feature_thumb\/media\/attachments\/2025\/01\/event_130486_original-1.jpeg" }, "occurrence_count":1, "first_occurrence":21866105 } }