On Oscillation-Free Emergency Navigation via Wireless Sensor Networks

Abstract

Emergency navigation is an emerging application of wireless sensor networks with significant research and social value. In order to ensure the safe and timely navigation of the evacuees, most of the existing works model navigation as a path-planning problem or movement decision support problem and adopt different metrics, such as the shortest route, the minimum exposure path, and the maximum safe distance. Without sufficient consideration of the dynamics of danger, the existing approaches are likely to cause users to move back and forth during navigation, known as oscillation. Frequent oscillations inevitably result in the user remaining in danger for a longer period of time, amplification of the user's panic, and eventual decrease in the chances of survival. In this paper we take users' oscillations in the dynamic environments into account and quantify the local success rate of navigation using a metric called ENO (Expected Number of Oscillations). We then propose OPEN, an oscillation-free navigation approach that minimizes the probability of oscillation and guarantees the success rate of emergency navigation. We implement OPEN and evaluate its performance through the trace from our system and extensive simulations. The results demonstrate that OPEN outperforms the current state-of-the-art approaches with respect to user safety and navigation efficiency.

ANT: Deadline-Aware Adaptive Emergency Navigation Strategy for Dynamic Hazardous Ship Evacuation With Wireless Sensor Networks

“…where γ denotes the angle between − − → [15] (Section 3.4.1) for a detailed description of the computation of vel…”

“…To evaluate the efficiency of ANT, we compare it with the OPEN approach [15] and MA approach [13] from four perspectives, namely, the average path length, user escape time, navigation success ratio, and minimum distance to hazardous regions. We use a network topology of a grid partitioned with 1024 to 16,384 nodes in a rectangular area.…”

“…However, without predicting the tendency of emergency dynamics, e.g., expansion, shrinkage, and movement, the selected "safe" paths may be blocked by abrupt changes in hazards, thus leading to re-navigation and user oscillation. To solve this problem, follow-up studies [15]- [21] have been conducted considering the dynamics of environments and making proactive navigation decisions for users. For example, oscillation-free emergency navigation (OPEN) [15] provides navigation paths with the minimum probability of oscillation by tracking changes in hazards using a WSN and minimizing the proposed reachabilitybased path metric, i.e., the expected number of oscillations (ENO).…”

“…To solve this problem, follow-up studies [15]- [21] have been conducted considering the dynamics of environments and making proactive navigation decisions for users. For example, oscillation-free emergency navigation (OPEN) [15] provides navigation paths with the minimum probability of oscillation by tracking changes in hazards using a WSN and minimizing the proposed reachabilitybased path metric, i.e., the expected number of oscillations (ENO). These emergency navigation methods can minimize passive oscillations by making detours, thereby enhancing the path reachability in general scenarios.…”

“…However, because of the unique environmental characteristics of accidents in ships, these state-of-the-art oscillationfree emergency navigation techniques [15]- [17] cannot be directly applied on these ships. The main reason is that the ship may tilt and eventually capsize owing to water ingress after a collision or grounding [22] [23], leading to two challenges.…”