## 3 Methodology
### Data Preprocessing
#### 3.1.2 Data Conversion  
Because the unit measurement of various fire hazard characteristics in the collected data set by the urban IoT monitoring system is not uniform, in order to realize the quantification and classification of prediction results, a quantifiable threshold interval is designed to classify and quantify various fire safety hazards. The dynamic fire risk of stadiums usually needs to be comprehensively considered from both static and dynamic indicators. Static indicators are considered from both inside the building (fire resistance rating, evacuation facilities and firefighting facilities and equipment configuration, etc.) and outside the building (fire separation distance, fire lane, rescue site, etc.). Among them, whether the fire resistance level, fire protection facilities and equipment configuration, fire separation distance, etc., meet the design specifications or whether the performance-based design is reasonable can be characterized by the indicator of \"pass fire protection acceptance\". The sealing method of the stadium has a great influence on the fire and smoke exhaust, and the index of the sealing degree of the building structure of the stadium is selected. The number of seats in the venue reflects the building scale and potential inherent risks of the venue to a certain extent, and the number of seats in the venue is selected as an indicator. In summary, the static indicators include building structure, venue size, fire protection acceptance, etc. The threshold interval of venue size and fire protection acceptance are divided according to the standard specification \"Uniform Standard for Civil Building Design (GB50352-2019)\" and \"Fire Protection Law of the People's Republic of China (2019)\". The threshold interval of the building structure is divided by referring to the relevant literature [16]. The details are shown in Table 2.  
In addition to the inherent safety attributes of buildings, other factors are used as dynamic disturbance factors, including three aspects: personnel management, facility equipment management and hidden danger management. Among them, personnel management mainly considers the on-the-job situation (system punching, video surveillance), training situation (number of licensees, uploading safety training records), and fire drills (uploading drill records and time calculation). The hidden danger management mainly considers the completion rate of inspection points, the stock of hidden dangers, the highest level of hidden dangers, and the rectification of hidden dangers. Facility and equipment management mainly considers the fire main engine, automatic sprinkler system, fire hydrant fire extinguishing system, fire door/fire shutter, smoke prevention and exhaust system, fire pool/water tank, and unit maintenance. Taking the main engine of fire fighting equipment as an example, the threshold design is shown. Obtain the number of fault points and online points on the fire host through real-time monitoring, and design a quantifiable indicator \"failure ratio\". Failure ratio refers to the ratio of the number of fault points on the host and the number of online points. According to relevant literature, if the failure rate is 0%, it will be Level I (90-100 points), which is not at risk. If the failure ratio is (0%, 5%), it is a Level II (80-90 points), which belongs to low risk. The threshold interval of fire host status and fire host power detection