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Rajesh Kalyanam

Publications and source records attributed to Rajesh Kalyanam.

3 recordsLinked to original sources

Risk-Prone and Risk-Averse Behavior in Natural Emergencies: An Appraisal Theory Approach

Individuals who shared actionable information during Hurricane Sandy were significantly more likely to exhibit risk-prone behavior, as measured by a novel Risk Behavior Quotient (RBQ). Using a dataset of 36595 geo-located tweets from 774 users in the New York area, we found that a higher proportion of actional tweets predicted increased exposure to physical even if overall users ultimately moved toward lower-risk zones. This counterintuitive finding suggests that proactivity, manifested in sharing crisis relevant content, correlates with greater exposure to risk, possibly due to increased mobility or engagement in hazardous areas. In contrast, a greater number of social media peers was associated with reduced risk exposure. This study builds on appraisal theory, which frames risk-related decisions as outcomes of cognitively mediated emotional and rational evaluations. We extend this theory to digital crisis behavior, distinguishing between emotional and actional appraisals expressed via social media. Tweets were categorized using sentiment analysis and semantic classification, enabling the isolation of affective and behavioral signals. Our methodology combines natural language processing with spatial vector analysis to estimate individual movement paths and risk exposure based on evacuation and flooding maps. The resulting RBQ captures both direction and intensity of risk behavior, allowing us to model how online communication reflects and predicts real-world risk engagement during natural disasters.

cs.SI

Self-Supervised Large Scale Point Cloud Completion for Archaeological Site Restoration

Point cloud completion helps restore partial incomplete point clouds suffering occlusions. Current self-supervised methods fail to give high fidelity completion for large objects with missing surfaces and unbalanced distribution of available points. In this paper, we present a novel method for restoring large-scale point clouds with limited and imbalanced ground-truth. Using rough boundary annotations for a region of interest, we project the original point clouds into a multiple-center-of-projection (MCOP) image, where fragments are projected to images of 5 channels (RGB, depth, and rotation). Completion of the original point cloud is reduced to inpainting the missing pixels in the MCOP images. Due to lack of complete structures and an unbalanced distribution of existing parts, we develop a self-supervised scheme which learns to infill the MCOP image with points resembling existing "complete" patches. Special losses are applied to further enhance the regularity and consistency of completed MCOP images, which is mapped back to 3D to form final restoration. Extensive experiments demonstrate the superiority of our method in completing 600+ incomplete and unbalanced archaeological structures in Peru.

cs.CV

Design and Deployment of Photo2Building: A Cloud-based Procedural Modeling Tool as a Service

We present a Photo2Building tool to create a plausible 3D model of a building from only a single photograph. Our tool is based on a prior desktop version which, as described in this paper, is converted into a client-server model, with job queuing, web-page support, and support of concurrent usage. The reported cloud-based web-accessible tool can reconstruct a building in 40 seconds on average and costing only 0.60 USD with current pricing. This provides for an extremely scalable and possibly widespread tool for creating building models for use in urban design and planning applications. With the growing impact of rapid urbanization on weather and climate and resource availability, access to such a service is expected to help a wide variety of users such as city planners, urban meteorologists worldwide in the quest to improved prediction of urban weather and designing climate-resilient cities of the future.

cs.DC