Charles R. Collins

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A circle packing is a configuration P of circles realizing a specified pattern of tangencies. Radii of packings in the euclidean and hyperbolic planes may be computed using an iterative process suggested by William Thurston. We describe an efficient implementation, discuss its performance, and illustrate recent applications. A central role is played by new(More)
The national HIV/AIDS prevention program, the Diffusion of Effective Behavioral Interventions (DEBI), is described in the context of addressing Hispanics/Latinos at risk for HIV/AIDS in the United States and Puerto Rico. The eight-step DEBI model is referenced in terms of the interventions and Division of HIV/AIDS Prevention/Capacity Building Branch(More)
This thesis represents the first formal presentation of the algorithm for-machine reconstruction from spectral data called-machine spectral reconstruction theory or MSR. As might be expected from a work that introduces a novel approach—let alone one that is written by a student to satisfy the requirements of a degree—there is significant attention given to(More)
We use a simple example to introduce a notion of curvature flow in the conformal mapping of polyhedral surfaces. The inquiry was motivated by experiments with discrete conformal maps in the sense of circle packing. We describe the classical theory behind these flows and demonstrate how to modify the Schwarz-Christoffel method to obtain classical numerical(More)
Community problem solving is believed to help coalitions achieve community changes and subsequent population-level reductions in targeted community health problems. This study empirically examined a community problem solving model used by CADCA, a national coalition training organization, to determine if the model explains how coalitions become effective(More)
This paper joins relational empowerment, youth empowerment, and Bridging Multiple Worlds frameworks to examine forms of relational empowerment for children in two intermediary institutions-school and a youth participatory action research after-school program (yPAR ASP). Participants were twelve children, most of whom were Latina/o and from im/migrant(More)
This study expanded the citizen participation literature by examining the dynamic nature of citizen participation and the extent to which the factors associated with citizen participation may be moderated by resident leadership status. Longitudinal survey data collected from 542 residents in one small Midwestern city implementing a community change(More)
Collective efficacy is defined as residents' perceived collective capacity to take coordinated and interdependent action on issues that affect their lives. This study explored factors associated with neighborhood collective efficacy among residents. Utilizing a national sample of 4,120 urban households provided by Annie E. Casey Foundation's Making(More)
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