arXiv subjects

Gregory L. Tangonan

Publications and source records attributed to Gregory L. Tangonan.

3 recordsLinked to original sources

arXiv2025

Predicting Power Grid Failures Using Self-Organized Criticality: A Case Study of the Texas Grid 2014-2022

This study develops a novel predictive framework for power grid vulnerability based on the statistical signatures of Self-Organized Criticality (SOC). By analyzing the evolution of the power law critical exponents in outage size distributions from the Texas grid during 2014-2022, we demonstrate the method's ability for forecasting system-wide vulnerability to catastrophic failures. Our results reveal a systematic decline in the critical exponent from 1.45 in 2018 to 0.95 in 2020, followed by a drop below the theoretical critical threshold ($α$ = 1) to 0.62 in 2021, coinciding precisely with the catastrophic February 2021 power crisis. Such predictive signal emerged 6-12 months before the crisis. By monitoring critical exponent transitions through subcritical and supercritical regimes, we provide quantitative early warning capabilities for catastrophic infrastructure failures, with significant implications for grid resilience planning, risk assessment, and emergency preparedness in increasingly stressed power systems.

stat.AP↗

arXiv2025

A Self-Organized Criticality Model of Extreme Events and Cascading Disasters of Hub and Spoke Air Traffic Networks

Critical infrastructure networks--including transportation, power grids, and communication systems--exhibit complex interdependencies that can lead to cascading failures with catastrophic consequences. These disasters often originate from failures at critical points in the network, where single-node disruptions can propagate rapidly due to structural dependencies and high-impact linkages. Such vulnerabilities are exacerbated in systems that have been highly optimized for efficiency or have self-organized into fragile configurations over time. The U.S. air transportation system, built on a hub-and-spoke model, exemplifies this type of critical infrastructure. Its reliance on a small number of high-throughput hubs means that even localized disruptions--especially those triggered by increasingly frequent and extreme weather events--can initiate cascades with nationwide impact. We introduce a novel application of Self-Organized Criticality (SOC) theory to model and analyze cascading failures in such systems. Through a detailed case study of U.S. airline operations, we show how the SOC model captures the power-law distribution of disruptions and the long-tail risk of systemic failures, reflecting the interplay between structural fragility and climate shocks. Our approach enables quantitative assessment of network vulnerability, identification of critical nodes, and evaluation of proactive strategies for disaster risk reduction. The results demonstrate that the SOC model replicates the observed statistical patterns--frequent small events and rare, severe failures--offering a powerful systems-level framework for infrastructure resilience planning and emergency response.

physics.soc-ph↗

arXiv2019

Intelligent Sensors and Monitoring System for Low-cost Phototherapy Light for Jaundice Treatment

A prototype of a low-cost phototherapy light system (LPLS) was deployed by the Ateneo Innovation Center (AIC) at a public hospital in Metro Manila, Philippines. It underwent clinical investigation for two years under the supervision of licensed physicians in a public tertiary hospital. This paper presents the process of upgrading the LPLS in order to enhance capabilities and improve efficiency yet remain affordable. The following features were added: (1) a visual and auditory monitoring system in order to remotely oversee the infant from the nurse station; (2) an automation system that stores data about the device's light intensity and bulb temperature and records ambient humidity; (3) an alarm system that activates the warning lights if sensor readings are in critical level and if the bulbs need to be replaced; and (4) a time setting to manually set the time of operation and automatically turn-off the device as programmed. The upgrades increased the system's cost but it remained cheaper than the ones commercially available. For deployment in remote or off-grid hospitals, the system was equipped with a solar-powering provision.

physics.med-ph↗