# Asian Affective and Emotional State (A2 ES) Dataset of ECG and PPG for Affective Computing Research
## 3 Data Collection Protocol  
### Emotion Annotation and Stimuli Selection  
The labelling and annotating of the A2 ES data were conducted based on the discrete emotional model (DEM), also known as basic emotions [16]. The seven selected basic emotions were happy, sad, anger, fear, disgust, surprise, and neutral. The self-labelling process was conducted directly after the subjects watched each video. A self-assessment form, as shown in Figure 3, was prepared and a brief description for the user on how to comply was written for the first video assessment. The subjects were encouraged to be truthful concerning their introspective emotions instead of thinking of what is expected from the videos. The first part identified the emotion experienced from watching the video, and the second part requested the subjects to rate the intensity of the emerged feeling on a scale, where one was the lowest and five was the highest. The combination of these two parts allowed us to map the emotion to the valence and arousal scale. The experiment was designed to collect data with an equal distribution of the six emotions to promote variation and reduce bias. Prior to the data collection, a pilot study on stimuli selection with respect to the targeted emotion was conducted. The findings of the pilot study are presented in [59]. Based on the outcome of the pilot study, the stimuli selection was refined. The stimuli were suited to the targeted participant's background. All videos were procured from YouTube, with a duration ranging from one to five minutes. The total duration of all of the video clips was 1 h 15 min. The subjects were presented with one neutral video before and after three consecutive videos with a similar targeted emotion. The targeted emotional sequence was happy > surprise > fear > disgust > sad > anger, with an interlude of a neutral video. The list of the 25 selected videos used to elicit an emotional response for the data collection can be found in [60]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Dataset** & **Data** & **Stimuli Used** & **Modalities Used** & **Cardiac-Based Devices** & **Emotion Label** \\ \hline EMDC [53] & 3 subjects, 360 stimuli & Audio & ECG, EMG, GSR, RESP & Procomp\({}^{2}\) Infiniti & Valence, arousal \\ \hline K-EmoCon [19] & 32 subjects & Naturalistic conversation & ECG, PPG, EEG, GSR, TEMP & Polar H7 (ECG), Empatica E4 (PPG) & Valence, arousal \\ \hline MAHNOB-HCI [57] & 27 subjects, 20 stimuli & Audio–visual & ECG, EEG, GSR, RESP, TEMP & Biosemi ActiveTwo & Valence, arousal, dominance \\ \hline MPED [16] & 23 subjects, 28 stimuli & Audio–visual & ECG, EEG, GSR, RESP & Biopac System & Joy, funny, anger, fast, disgust, sad, neutral \\ \hline RECOLA [58] & 46 subjects & Spontaneous and naturalistic interactions & ECG, GSR, voice, facial expression & Biopac MP36 & Valence, arousal \\ \hline SWELL [5] & 25 subjects, 4 working conditions with stressors & Writing, presenting, reading, searching task & ECG, GSR, facial expression, body posture & Mobi (TMSi) & Valence, arousal, stress \\ \hline WESAD [29] & 15 subjects, 10 stimuli & Audio–visual, public speaking, mental arithmetic task & ECG, PPG, GSR, EMG, TEMP, RESP & RespiBan (ECG), Empatica E4 (PPG) & Neutral, stress, amusement \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._The ECG signals were recorded using a Kardia-Mobile (KM) device. KM is a one-lead ECG device by AliveCor. It works by placing two fingers of each hand on the electrodes (Figure 4). It can capture 30, 60, or 300 s of raw and filtered ECG data and transfer them to the connected smartphone via an ultrasonic audio-based wireless communication protocol. Several studies have assessed and validated the KM device and its algorithm. The sensitivity and specificity obtained varied between 55-100% and 84-99%, respectively, depending on the patient population and reference technique [61; 62; 63; 64; 65; 66]. The PPG was collected using a Maxim Band.