## 2 Materials and Methods
### Comparison of Energy Consumption of Voice Assistants Between Active and Passive States  
To verify the behavior of devices using VAs regarding their energy consumption, tests were conducted to gather relevant data on battery consumption when the devices execute functions that respond to voice commands. The tests were performed in two different scenarios. In the first scenario, the devices had the VAs in active mode (or On state), utilizing the VAs' functions. In the second scenario, the VAs were in passive mode (Off state), meaning the devices were not using the assistant's functions. The main objective of these tests is to compare the results obtained between the two states and calculate an average of energy consumption in each situation. Considering that there are numerous VAs [38], including both speaker-type devices like Google Home or Amazon Echo and virtual assistants integrated into mobile devices such as Google Assistant (GA), Apple's Siri, or Microsoft's Copilot, some with AI capabilities, the two most commonly used voice assistants in mobile and desktop devices were selected: GA and Copilot, which also function on Android and Windows operating systems [39; 40]. Basic tests were conducted using these assistants, implementing consumption measurement software to identify significant differences that can be crucial for resource optimization in various processes. Table 2 presents the characteristics of the devices used. In these tests, the energy consumption of these two VAs was measured over 60 min, During this period, 120 queries were conducted, and the battery level was measured every minute. From these results, the arithmetic mean of battery consumption was calculated. Figure 2 shows the average percentage of battery consumption with standard deviations of 0.033% and 0.007% for Copilot in active and passive states, respectively, and 0.021% and 0.004% for GA in active and passive states, respectively. From the results obtained, similar discharge behaviors between each test are evident, with a significant graphical difference between passive and active states, showing that devices exhibit higher energy consumption while running the VA compared to when this function is idle. Mobile device tests showed that the battery percentage consumed over 60 min was 8% in the active state and 4% in the passive state, which means that, in the active state, the battery duration is approximately half compared to the operating time in the passive state. Similarly, the difference was 43.5% between the two states on the laptop. The above corroborates a direct relationship between the use of VA functions and the device's energy consumption. Concerning this, measuring the discharge time of VAs starting at 100% battery until it reaches 0% shows that battery life, both on the laptop and mobile, lasts on average twice as long in the passive state as in the active state. Regarding the consumption of these devices, several power measurements were conducted on the equipment in operation, where values similar to the nominal were obtained. In total, 40 VA queries were conducted and measured using a digital power meter (watts), brand Suraielec (Zhengzhou Suraielec Network Tech Co, Zhengzhou, China), with a resolution of 0.1 W. The average power \begin{table}
\begin{tabular}{c c c} \hline \hline
**Characteristics** & **Mobile Phone** & **Laptop** \\ \hline \multirow{2}{*}{Device} & Cellular Xiaomi, Redmi Note 12S & Laptop Asus, VivoBook M509 DA \\  & (Xiaomi Communications Co, Ltd., Beijing, China) & (ASUSteK Computer Inc., Taipei, Taiwan) \\ \hline \multirow{2}{*}{Processor} & Octa Core 2.2 Ghz—MediaTek Helio G96 & Octa core de 2.1 Ghz, AMD—Ryzen5 \\  & (MediaTek Inc., Hsinchu, Taiwan) & (Advanced Micro Devices, Inc., Santa Clara, CA, USA) \\ \hline Memory & RAM: 12 GB & RAM: 12 GB \\ \hline Operating system & Android 14 & Windows 11 pro-64 bits \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Characteristics of devices with VAs.