# Bushfire Disaster Monitoring System Using Low Power Wide Area Networks (LPWAN)
## 4 Application  
A series of bushfires known as Black Saturday burned across the state of Victoria, Australia, on 7 February 2009 during extreme weather conditions. Around midday, wind speeds reached their peak and along with arid conditions, sparked a bushfire that became the deadliest and most intense firestorm ever experienced in Australia's history. This disaster resulted in the deaths of 173 people, with 414 injured, 450,000 hectares of area burned and an economic loss of more than $4 billion USD [31; 32]. For the purposes of demonstration, a bushfire scenario is considered to simulate sensed data collection by gateways for transmission to the DRA, where the data can be analysed for predicting areas that may be further impacted. Sensed data within LPWANs may be aggregated at a gateway independently from public networks. The original sensor's (triggered sensor) LID and timestamp is relayed to the next sensor until it reaches a gateway. Figure 3 demonstrates that at a particular time \(T_{1}\), Area1 is affected by the disaster, and by \(T_{2}\), it has spread to Area2. Eventually at \(T_{3}\) and its affected area, our aim is to forecast the Area4 at \(T_{4}\) using the previous data, that is, Areas (location information), at times \(T_{1}\), \(T_{2}\) and \(T_{3}\). The directions of propagation are constantly calculated and reflected in the forecast, which will be recalculated for each subsequent time period. In other words, the estimated area of Area4 and the area that is actually affected at \(T_{4}\) are used to forecast Area5 at \(T_{5}\). Figure 2: Emergency procedures of LPWAN gateways. Bushfire behaviour is rather complex. It varies widely depending on variables such as air temperature, humidity, wind speed and direction, terrain, fuel load in the form of dry vegetation, as well as many other factors. Theoretical models for fire prediction which take these into account have been designed and are being constantly improved. One of the most high-resolution methods of bushfire measurements for monitoring and theoretical model verification purposes rely on expensive surveys using on-board infrared equipment on aircraft flying over the fire, which are unable to provide continuous data for extended periods of time. It should be mentioned that the sensor network approach relies on actual measurements received from the sensors at regular intervals, which allows for timely correction of any differences between measured and predicted data. LID and timestamp information, as well as signal status, are vital information in identifying areas affected by the disaster. For example, sensor S\({}_{\text{IN}}\) as shown in Figure 3 is considered to be affected when the gateway loses its signal in comparison to the previous time it was online [\(T=T_{N}-(T_{N-1})\)]. The prediction of areas of future impact can be calculated as follows. The parameters of interest from each sensor can be represented by a matrix that mirror sensor locations. \[ \begin{array}{cccc}P_{11}&P_{12}&\ldots&P_{1N}\\ P_{21}&\ldots&\ldots&\ldots\\ \ldots&\ldots&\ldots&\ldots\\ P_{M1}&\ldots&\ldots&P_{MN}\end{array}  \tag{1}\]  
In bushfire monitoring for instance, the parameter of interest \(P_{MN}\) is the air temperature at each sensor. When the number of sensors returning parameter values exceeding the threshold allowed is reached, the disaster response is triggered. The direction of propagation, its rate of change and its velocity can be calculated by knowing the geographical position (\(xy\) coordinates) of the triggered sensors (\(x_{MN}\), \(y_{MN}\)), the time this occurred (\(T_{1}\)), and then tracking the propagation of the increased parameter values to the surrounding sensors at \(T_{2}\). Considering an ambient temperature of 25 \({}^{\circ}\)C, a contour plot example of the temperature distribution that has been read from the sensor networks is shown in Figure 4. The location of each sensor has been shown as an overlay. At \(T_{1}\), a number of sensors that have exceeded the trigger temperature (\(P_{tr}\)) are shown by the red zone.