Towards Debris Information Analysis and Abstraction for Wi-Fi Radar Edge in Collapsed Structures

Abstract

Structural collapses are widespread, owing to a surge in climatic changes, earthquakes, and terrorism. Therefore, there are some technological rescue methods in practice that involve sensors, radars, cameras, microphones, and robots. However, deployment of these techniques faces at least one issue amongst cost, availability, and technical expertise, which limits their application in developing countries. So, there is a dire need for a low-cost and easy deployable rescue method. Recently, we witnessed an increasing trend of using Wi-Fi radios as sensing modality for various applications, including breathing detection and localization, thus leading to device-free communication. Based on this, we may envisage having a Wi-Fi rescue solution. However, Wi-Fi signals cannot easily penetrate through collapsed structures due to the multilayered obstacle scenario. So, in this study, we focus our research on the proper information analysis and abstraction of debris and also present the possible methodology to have better coverage for Wi-Fi signals using Wi-Fi radar edge. We define two objectives of this work; 1) debris information analysis and 2) the Wi-Fi signal propagation mechanism, respectively. We achieve our first goal by conducting site surveys of earthquake-hit areas that enable us to analyze the causes and types of structural collapses followed by debris concept selection model. We employ a bijective soft set approach to accurately select the debris based on the complexity and nature of structural engineering followed. Moreover, we use the Wi-Fi Halow radar edge for wireless signal propagation and perform extensive simulations at low power. Finally, we compare both methods and discuss prospects. INDEX TERMS Collapsed structure, coverage, debris, rescue, bijective soft set, Wi-Fi radar. I. INTRODUCTION Post-disaster rescue from collapsed structures using ubiquitous methods is getting more attention from the research community owing to the surge in climate changes, earthquakes, war, and terrorism [1]. According to studies [2], [3], the first 72 hours are very crucial for the survival of missing or trapped humans. Therefore, there are many rescue techniques in literature, such as robots, cameras, radars, and sensors, etc. However, cost and non-availability limit applications of these methods in developing countries. But, with the realization of leveraging Wi-Fi signals as sensing The associate editor coordinating the review of this manuscript and approving it for publication was Honghao Gao. information [4], the research trend has shifted to widget free solutions in each domain, as these are readily available and deployable. However, these Wi-Fi signals are weak if subjected to penetration through collapsed structures for rescue. So, in this paper, we study the nature of debris and its proper modeling to address the weak Wi-Fi signal strength through a low-powered Wi-Fi radar approach. A. PRIOR WORK AND MOTIVATION We observe that natural and human-made phenomena such as climatic changes, earthquakes, fire, war, and te...