# A Sensor Data-Driven Decision Support System for Liquefied Petroleum Gas Suppliers
## 6 Key Performance Indicators
The indicator values were analyzed for a period of time, client, group of clients, location, and type of service. Table 1 features seven KPI examples for the customer tank area. Finally, it is worth completing the presented KPI description with the perspective of the system that was created. The values of the KPIs are calculated by means of the analytic server once a day and stored in the data repository as two tables, of which one stores the values of the PIs, the other the KPIs. The tables have the form of columns as the number of indicators is predefined. Adding new indicators results in a new table in the the data repository. The basic period for which a KPI is calculated is one day; other periods are one week, two weeks, one month, one quarter, and one year. The database stores all aggregated values. After each of these aggregation periods, the new values of the indicators are calculated automatically, which makes the visualization and analysis of indicator values very fast. KPI visualization enables various analyses. KPI values can \begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Indicator Name** & **Units** & **Description** \\ \hline Total Residual Space & L & Unused spaced in the tank directly after the delivery. The lower the value is, the better [0, tank capacity). \\ \hline Relative Drop Size & \% & The volume of delivery expressed as the quotient of the supplied gas to the tank’s capacity (expressed in \%). For a bigger number of deliveries, a bigger number of tanks, etc., an average value is calculated that can serve as a reference value for single tanks. The higher the value is, the better [0, 100]. \\ \hline \(LL\) Level & & The number of registered gas levels below the \(L\) threshold value. The lower the value is in the range [0, inf), the better, as the gas level in a tank should not drop below level \(L\). \\ \hline Unit Trip Load Efficiency & \% & Delivery efficiency expressed as the quotient of the number of actually performed deliveries to the theoretical number of deliveries assuming that each performed delivery has been fulfilled in an ideal manner (i.e., \(L\) is the level of gas in the tank(s) at the time of the delivery, while \(H\) denotes the level of gas in the tank after the delivery, which should not be exceeded). The value of the indicator is decreased by 1 in order to indicate the best performance by a 0 value, and it is expressed in \% as a value from the range [0, inf). This KPI can also be calculated for each tank separately and compared with the average value for the bigger number of tanks. \\ \hline Illegal Loads & & Calculated as the difference between the number of deliveries to the tank identified on the basis of telemetric data and the number of deliveries to the tank according to the distributor’s data. The lower the value is, the better [0, in). \\ \hline Customer Consumption & L & Volume of gas used. \\ \hline Low/High Level Time & Min & Time exceeding the level of gas below (above) values \(LL\), \(L\), \(H\), and \(HH\). The indicator values can be calculated for each tank separately. The lower the value is, the better [0, inf). \\ \hline \hline \end{tabular}
\end{table} 
Table 1: KPI examples for the customer tank area. be analyzed taking into consideration different perspectives (dimensions) such as a fixed period of time, client, group of clients, location, and type of service. The indicator values can be compared in the successive periods of time. Therefore, the target line or the value range in which the KPI should fit can be defined, and the trend line enabling prediction of future KPI values can be adjusted.