Browsing by Author "Qiu, Cheng"
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Item Aging in Place: City of North Saint Paul - Multidisciplinary Perspectives on Aging(Resilient Communities Project (RCP), University of Minnesota, 2013) Benham, Chiara; Witzen, Kjersite; Schleichert, Clarissa; Qiu, Cheng; Jekal, Mee; Shin, Jihee; Lindberg, CarinaThis project was completed as part of the 2013-2014 Resilient Communities Project (rcp.umn.edu) partnership with the City of North St. Paul. With an increasingly aging population, the City of North St. Paul wanted to determine ways for its residents to age safely in their homes. Project lead Jon Fure partnered with students in Lisa Edstrom’s GERO 5105: Multidisciplinary Perspectives on Aging course. The students held focus groups with seniors to get their perspectives on aging in place and made recommendations based on these conversations. Identified barriers and suggested improvements were: transportation, chore services, and neighborhood stores and cafes. The final report, executive summary, and poster are available.Item Modulation by visual context beyond local features(2015-12) Qiu, ChengWe rarely see an isolated visual stimulus all alone by itself. Rather, the stimulus tends to be surrounded by spatial and temporal context, which often affect both the perception and cortical responses to the target stimulus. The contextual information in fact can be fairly rich, and its effects can be very complex, which in many cases have not been fully explored. This thesis uses functional magnetic resonance imaging (fMRI), psychophysics, and computational modeling to examine the effects and functions of the contextual modulation especially beyond local features. In Chapters 2 and 3, two sets of experiments considering a larger context including the global shape complexity and figure-ground segregation are used to reconcile competing branches of the literature in terms of the cortical response patterns of early visual areas. In particular, those cortical responses to coherent structure-from-motion stimuli or circular contours vary dramatically depending on the global context. In Chapters 4 and 5, two sets of psychophysical experiments use the tilt illusion and the shape distortion, respectively, as probes to further explore the functions of local and global context. Overall, the ability to take account larger context ensures the system would dynamically adjust weights between an efficient representation and a strategy to emphasize targets and indicate certainty in early visual areas. Additionally, a stronger perceptual grouping cue between the target and its surround or a larger uncertainty of the center target would enhance the contextual modulation and increase perceptual biases, which would potentially increase the sensitivity of visual system to feature discrepancies, and it would play an important role in visual search and detection.