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"Emergency communication systems Japan."
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UAV Trajectory Optimization in a Post-Disaster Area Using Dual Energy-Aware Bandits
Over the past few years, with the rapid increase in the number of natural disasters, the need to provide smart emergency wireless communication services has become crucial. Unmanned aerial Vehicles (UAVs) have gained much attention as promising candidates due to their unprecedented capabilities and broad flexibility. In this paper, we investigate a UAV-based emergency wireless communication network for a post-disaster area. Our optimization problem aims to optimize the UAV’s flight trajectory to maximize the number of visited ground users during the flight period. Then, a dual cost-aware multi-armed bandit algorithm is adopted to tackle this problem under the limited available energy for both the UAV and ground users. Simulation results show that the proposed algorithm could solve the optimization problem and maximize the achievable throughput under these energy constraints.
Journal Article
Instantaneous tracking of earthquake growth with elastogravity signals
Rapid and reliable estimation of large earthquake magnitude (above 8) is key to mitigating the risks associated with strong shaking and tsunamis
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. Standard early warning systems based on seismic waves fail to rapidly estimate the size of such large earthquakes
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–
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. Geodesy-based approaches provide better estimations, but are also subject to large uncertainties and latency associated with the slowness of seismic waves. Recently discovered speed-of-light prompt elastogravity signals (PEGS) have raised hopes that these limitations may be overcome
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,
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, but have not been tested for operational early warning. Here we show that PEGS can be used in real time to track earthquake growth instantaneously after the event reaches a certain magnitude. We develop a deep learning model that leverages the information carried by PEGS recorded by regional broadband seismometers in Japan before the arrival of seismic waves. After training on a database of synthetic waveforms augmented with empirical noise, we show that the algorithm can instantaneously track an earthquake source time function on real data. Our model unlocks ‘true real-time’ access to the rupture evolution of large earthquakes using a portion of seismograms that is routinely treated as noise, and can be immediately transformative for tsunami early warning.
A deep learning model trained on prompt elastogravity signal (PEGS) recorded by seismometers in Japan predicts in real time the final magnitude of large earthquakes faster than methods based on elastic waves.
Journal Article
Communication Problems After the Great East Japan Earthquake of 2011
After the 2011 Great East Japan Earthquake, the resource utilization of and the problems encountered with communication devices were examined.
A questionnaire survey was submitted to disaster medical assistance teams (DMATs) that were at the primary sites of destruction after the earthquake.
We collected data from 196 teams. During the first 4 days after the earthquake, the use of mobile phones, laptop computers, and landline phones was rated as poor to moderate, and satisfaction was very low, while satisfaction with satellite phones was rated as good to moderate (50%). The degree of satisfaction continued to increase gradually over time. Satellite phones, however, had several problems: poor reception, line instability, voice call use only, and inability to send large amounts of data.
To ensure effective communication during the acute phase in the aftermath of large disasters, a new satellite communication device is needed that not only is portable, battery powered, and able to send large volumes of data, but also offers stable communication.
Journal Article
Novel information and communication technology system to improve surge capacity and information management in the initial hospital response to major incidents
[...]in a US survey, only 43% of respondents considered the phone tree an effective method of contacting in-house staff in a disaster situation [14]. [...]our study showed the utility of simultaneous transmission using ICT. [...]our system had several advantages over existing mobile phone applications such as SMS text messaging or messenger applications. [...]ICT can notify thousands of people at once, whereas SMS text messaging or messenger applications are limited in the number of destinations which a single message can simultaneously send to [21].
Journal Article
Risk evaluation and warning threshold of unstable slope using tilting sensor array
Slope monitoring and early warning systems are a promising approach toward mitigating landslide-induced disasters. Many large-scale sediment disasters result in the destruction of infrastructure and loss of human life. The mitigation of vulnerability to slope and landslide hazards will benefit significantly from early warning alerts. The authors have been developing monitoring technology that uses a micro-electro-mechanical systems tilt sensor array that detects the precursory movement of vulnerable slopes and informs the issuance of emergency caution and warning alerts. In this regard, the determination of alarm thresholds is very important. Although previous studies have investigated the recording of threshold values by an extensometer which installation of an extensometer at appropriate sites is also difficult. The authors prefer tilt sensors and have proposed a novel threshold for the tilt angle, which was validated in this study. This threshold has an interesting similarity to previously reported viscous models. Additionally, multi-point monitoring has recently emerged and allows for many sensors to be deployed at vulnerable slopes without disregarding the slope’s precursory local behavior. With this new technology, the detailed spatial and temporal variation of the behavior of vulnerable slopes can be determined as the displacement proceeds toward failure.
Journal Article
Driving Sustainable Disaster Risk Reduction: A Rapid Review of the Policies and Strategies in Saudi Arabia
This article presents a comprehensive rapid review of the current disaster risk reduction (DRR) efforts in Saudi Arabia, a country exposed to a variety of hazards such as extreme heat, droughts, floods, dust, and sandstorms, along with threats from terrorism and violence. Employing a rapid review approach, our aim was to provide timely insights into DRR strategies, with an emphasis on the unique geographical and socio-political context of Saudi Arabia. This study serves as a valuable reference for similar hazard-prone regions worldwide. Our review encompasses Saudi Arabia’s progress in key areas, such as improving building codes and infrastructure, developing early warning systems, raising public awareness, and strengthening emergency response capabilities. While Saudi Arabia has made commendable strides in implementing international best practices for DRR, our review also identified specific areas where further development and enhancement are needed. These include the need for more sophisticated early warning systems, expanded public awareness campaigns, and continual enhancements in emergency response capabilities. This review offers key insights into the challenges and opportunities within Saudi Arabia’s DRR efforts, highlighting the steps that Saudi Arabia has taken towards resilience. Drawing from specific examples of past disasters, our findings shed light on practical considerations for improving disaster risk management, with the potential to inform policy, enhance public awareness, and contribute to building a safer and more resilient future in Saudi Arabia.
Journal Article
Uttarakhand State Earthquake Early Warning System: A Case Study of the Himalayan Environment
The increased seismic activity observed in the Himalayas, coupled with the expanding urbanization of the surrounding areas in northern India, poses significant risks to both human lives and property. Developing an earthquake early warning system in the region could help in alleviating these risks, especially benefiting cities and towns in mountainous and foothill regions close to potential earthquake epicenters. To address this concern, the government and the science and engineering community collaborated to establish the Uttarakhand State Earthquake Early Warning System (UEEWS). The government of Uttarakhand successfully launched this full-fledged operational system to the public on 4 August 2021. The UEEWS includes an array of 170 accelerometers installed in the seismogenic areas of the Uttarakhand. Ground motion data from these sensors are transmitted to the central server through the dedicated private telecommunication network 24 hours a day, seven days a week. This system is designed to issue warnings for moderate to high-magnitude earthquakes via a mobile app freely available for smartphone users and by blowing sirens units installed in the buildings earmarked by the government. The UEEWS has successfully issued alerts for light earthquakes that have occurred in the instrumented region and warnings for moderate earthquakes that have triggered in the vicinity of the instrumented area. This paper provides an overview of the design of the UEEWS, details of instrumentation, adaptation of attributes and their relation to earthquake parameters, operational flow of the system, and information about dissemination of warnings to the public.
Journal Article
Learning From Japan: Strengthening US Emergency Care And Disaster Response
As Hurricane Katrina demonstrated in 2005, US health response systems for disasters-typically designed to handle only short term mass-casualty events-are inadequately prepared for disasters that result in large-scale population displacements. Similarly, after the 2011 Great East Japan Earthquake, Japan found that many of its disaster shelters failed to meet international standards for long-term provision of basic needs and health care for the vulnerable populations that sought refuge in the shelters. Hospital disaster plans had not been tested and turned out to be inadequate, and emergency communication equipment did not function. We make policy recommendations that aim to improve US responses to mass-displacement disasters based on Japan's 2011 experience. First, response systems must provide for the extended care of large populations of chronically ill and vulnerable people. Second, policies should ensure that shelters meet or exceed international standards for the provision of food, water, sanitation, and privacy. Third, hospital disaster plans should include redundant communication systems and sufficient emergency provisions for both staff and patients. Finally, there must be routine drills for responses to mass-displacement disasters so that areas needing improvement can be uncovered before an emergency occurs. [PUBLICATION ABSTRACT]
Journal Article
Development of an offshore ground motion prediction equation for peak ground acceleration considering path effects based on S-net data
Ground motion prediction equations (GMPEs) in offshore regions are important not only for earthquake early warning systems and strong motion prediction but also for evaluating the durability of subsea structures and tsunami risks associated with seafloor slope failures. Since soil conditions and propagation paths differ between onshore and offshore areas, it is desirable to develop a GMPE specific to the seafloor. Previous GMPE models have some problems, such as being influenced by buried observation equipment and path effects. In this study, to predict the distribution of seafloor seismic acceleration, we developed a new GMPE regressed on the peak ground acceleration (PGA) data of S-net using minimum necessary seismic parameters as explanatory variables. Residual analysis using the conventional GMPE emphasized the path effects through the offshore area, which were corrected by the depth up to the plate boundary. The new model successfully predicted PGA with smaller errors compared to conventional onshore and offshore GMPEs. The residuals between the observed and predicted PGAs were used to examine the factors responsible for the effects of the S-net site conditions. The new GMPE can predict PGAs within 300 km of the epicenter from the moment magnitude (Mw 5.4–7.4), focal depth, earthquake type, and source distance. In this model, the distance attenuation coefficient is smaller than in conventional models, and consequently, the PGAs along the trench axis that are amplified due to path effects can be reproduced. This means that PGAs will be unexpectedly larger than those estimated by conventional GMPEs even far from the hypocenter. Our model improves the accuracy of PGA prediction and avoids underestimation in assessing seafloor slope failure and earthquake resistance near the trench.
Graphical abstract
Journal Article