象山县异常船只评估数据

数据用于检测象山各船舶在敏感水域的航行行为，针对敏感水域快速和准确检测出行为异常船舶，为后续警告、监视和驱离等行动提供情报支撑。1.筛选出AIS数据中的触及到敏感水域的船舶信息，把这些信息存储后用于后续计算 2.计算船舶进出次数、停留时间：先根据进出水域时间来计算停留在敏感水域时间，最后统计船舶总共的进出次数，并将这些数据都存入数据库 3.计算速度比值：当船舶位于敏感水域且处于运动状态时，通过AIS数据直接获取的数据，并自动计算在水域的平均速度，并除以船舶固定的平均经济航速，获得速度比值 4.异常判断：对进出次数大于10次，停留时间大于15天，速度比值1.6的船舶在数据库中做异常标签标记

This dataset is used to detect the navigation behaviors of various ships in Xiangshan's sensitive waters, aiming to quickly and accurately identify ships with abnormal behaviors in sensitive waters and provide intelligence support for subsequent actions such as warning, monitoring and expulsion.
1. Screen out the ship information that has touched the sensitive waters from the AIS data, and store the screened information for subsequent calculations.
2. Calculate the number of entry and exit times and stay duration: First calculate the time a ship stays in the sensitive waters based on its entry and exit times from the waters, then count the total number of entry and exit times for each ship, and store all these data in the database.
3. Calculate the speed ratio: When the ship is located in the sensitive waters and in motion, directly obtain relevant data from the AIS, automatically calculate the average speed of the ship within the waters, then divide this value by the ship's fixed average economic speed to obtain the speed ratio.
4. Abnormality judgment: Mark ships that meet the following conditions in the database with an abnormal label: the number of entry and exit times is greater than 10, the stay duration is longer than 15 days, and the speed ratio equals 1.6.