With the emerging concept of Wi-Fi radio as sensors, we are witnessing more device-free sensing applications. But we observe that most of the existing works of these applications are meant for simple indoor layout and are not adequate for complex cases, e.g., collapsed structures. In this article, we explore the feasibility of Wi-Fi Halow signals for the collapsed scenario as it can boost rescue efforts. To achieve this, we aim at two prime objectives of this article. First, we model debris constituent of common collapsed scenario materials, such as concrete, brick, glass, and lumber by conducting a field survey of an earthquake-affected area. After that, we consider signal propagation models for better coverage in this debris model by employing two methods. The first method is an integrated TOPSIS and Shannon entropy-based on a bijective soft set, which provides us an approximation tool to select the best Wi-Fi Halow signal coverage in debris. The second method composes two modified wireless signal propagation models, which are transmitter-receiver (TR) and Wi-Fi radar, respectively. We perform extensive simulations and figure out that low power transmission using Wi-Fi radar can yield better coverage, which is also verified by the Shannon entropy method.

中文翻译：

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倒塌结构中的 Wi-Fi Halow 信号覆盖建模


随着 Wi-Fi 无线电作为传感器的概念不断涌现，我们正在见证更多无需设备的传感应用。但我们观察到，这些应用程序的大多数现有作品都是针对简单的室内布局，不足以应对复杂的情况，例如倒塌的结构。在本文中，我们探讨了 Wi-Fi Halow 信号在倒塌场景中的可行性，因为它可以促进救援工作。为了实现这一目标，我们致力于实现本文的两个主要目标。首先，我们通过对地震灾区进行实地调查，对常见倒塌场景材料（例如混凝土、砖块、玻璃和木材）的碎片成分进行建模。之后，我们通过采用两种方法来考虑信号传播模型，以更好地覆盖该碎片模型。第一种方法是基于双射软集的综合 TOPSIS 和香农熵，它为我们提供了一个近似工具来选择碎片中最佳的 Wi-Fi Halow 信号覆盖范围。第二种方法由两个修改后的无线信号传播模型组成，分别是发射器-接收器（TR）和Wi-Fi雷达。我们进行了大量的模拟，发现使用 Wi-Fi 雷达的低功率传输可以产生更好的覆盖范围，这也得到了香农熵方法的验证。