# Bloom Filter Approach for Autonomous Data Acquisition in the Edge-Based MCS Scenario +
## 4 Results and Discussion
### Evaluation of BF Algorithm
Similarly, when \(m_{MEC}\) is 10, the difference in savings for \(m_{worker}=1\) and \(m_{worker}=5\) is around 18.5% when _window_ is 1 min, and drops to 9.3% when filter validity period is 120 min. In addition, we can see that the total savings slowly increases with a decrease in the value of parameter \(m_{MEC}\) because an MCS application deployed on ME hosts requires fewer results. In particular, when workers submit only one result per _small_ MGRS area and the filter validity period is 120 min, the total savings goes up to 61.2% when \(m_{MEC}\) is 5 (see Figure 11a), while it is less than 1% lower when ME host needs up to 10 results per _small_ area (see Figure 11b). That is a significant result because savings remain pretty high even for many data readings required by an ME host. Our findings are summarized in Tables 2 and 3, which show the absolute difference in total savings for different input parameters. The first table shows the influence of parameter \(m_{worker}\) on total savings, where column \(m_{worker\_x,y}\) presents the absolute difference in savings (expressed as percentage) when we compare the savings result for \(m_{worker}=x\) and \(m_{worker}=y\) for different values of parameters \(window\) and \(m_{MEC}\) (e.g., the result in the first row of column \(m_{worker\_1,2}\) shows that the total savings is 6.73% higher for \(m_{worker}=1\) when filter reset is every 1 min and ME host requires 5 results per _small_ area), while the second table shows the influence of parameter \(m_{MEC}\) on total savings, where column \(m_{MEC\_x,y}\) presents the absolute difference in savings when \(m_{MEC}=x\) and \(m_{MEC}=y\) for different values of parameters \(window\) and \(m_{worker}\) (e.g., the result in the fifth row of column \(m_{MEC\_5,10}\) shows that the total savings is 0.95% higher for \(m_{MEC}=5\) when filter reset is every 120 min and worker submits only 1 result per _small_ area). The results indicate that the parameter \(m_{worker}\) has significant influence on the total savings when compared to the parameter \(m_{MEC}\). We can conclude that \(m_{MEC}\) is used to control the number of workers who can produce data in each _small_ MGRS area during an observed time slot (i.e., BF validity period), while \(m_{worker}\) is used to control the amount of data that each worker is going to produce per area. In other words, the significance of the parameter \(m_{MEC}\) is manifested only in cases when many redundant workers are located in the same 100 m\({}^{2}\) area during the same period. Finally, we analyze the influence of parameter \(m_{worker}\) on the cumulative amount of redundant data received by all ME hosts for different filter reset periods and application requirements in Figure 12. As already stated, a data reading is redundant if an ME host already contains the same combination of the observed parameter and _small_ MGRS area identifier in its BF structure. Note that the percentage of redundant results is expressed concerning the total data received by ME hosts. As expected, the highest percentage of redundant data is received when hosts require only five data readings per _small_ cell before updating the global filter for the area. The lowest amount of redundant data is received when hosts require 15 results for all observed scenarios, regardless of the time window  
Figure 11: Energy savings with respect to the parameter \(m_{MEC}\). Figure 10: Energy savings with respect to the parameter \(m_{worker}\). in which BF is reset and parameter \(m_{worker}\), because for smaller values of \(m_{MEC}\), hosts will update their filters very soon, and subsequently received results will be redundant. When we compare savings for different BF validity periods, we see that the amount of redundant results received by ME hosts grows when the time between BF resets increases. If the filter is valid only for a short period, the probability that more workers will be within the same _small_ MGRS area during the same time slot is low.