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BASELINE_EXPERIMENTS.md

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Baseline Experiments

This document presents a brief summary of reproducing results from the paper Introducing WESAD, a multimodal dataset for Wearable Stress and Affect Detection

Feature Extraction

Chest-worn device

  • Segmentation of the (preprocessed) sensor signals was done using a 60-second sliding window, with a window shift of 0.25 seconds and default sampling rate (700 Hz). A total of 79 (out of 81) features were computed. A summary of total windows obtained in the process is shown below
Subject Windows
S2 7764
S3 7900
S4 7941
S5 8148
S6 8088
S7 8073
S8 8116
S9 8068
S10 8388
S11 8192
S13 8185
S14 8189
S15 8212
S16 8165
S17 8384
TOTAL 121813

Wrist-worn device

  • WIP

Reproducing benchmark experiments

Using Chest-worn device data

  • We trained a Random Forest (RF), AdaBoost (AB) and Latent Discriminant Analysis (LDA) models suing different sets of sensor modalities.
  • Each setup was run five times so mean and std of scores are reported.
  • Final scores within each experiment were averaged using a LOSO (Leave One Subject Out) cross-validation.
  1. Evaluation using each of the six sensor modalities separately:
rf_f1 rf_acc rf_b_f1 rf_b_acc ab_f1 ab_acc ab_b_f1 ab_b_acc lda_f1 lda_acc lda_b_f1 lda_b_acc
ACC 0.395361 0.559278 0.569841 0.723911 0.448804 0.591598 0.588321 0.733027 0.400382 0.597001 0.542222 0.70007
ECG 0.518569 0.660007 0.7963 0.839966 0.515433 0.662472 0.800814 0.8441 0.515813 0.70816 0.809485 0.865115
EDA 0.643974 0.667019 0.749781 0.787745 0.621201 0.645761 0.741442 0.781814 0.451855 0.57464 0.692621 0.764252
EMG 0.462594 0.607954 0.599067 0.713775 0.480842 0.620192 0.610554 0.723836 0.445108 0.599009 0.614172 0.724727
RESP 0.545764 0.676278 0.78608 0.824339 0.544442 0.68253 0.785471 0.821546 0.545973 0.698706 0.796305 0.841577
TEMP 0.408837 0.499755 0.53513 0.642769 0.386727 0.494761 0.500478 0.61475 0.289719 0.575443 0.430318 0.705284

* Column names from above table have the following notation: {model}_{binary_classifier?}_{eval_score_metric}

  1. Evaluation scores using all modalities:
mean std
rf_f1 57.14 0.92
rf_acc** 69.07 0.62
rf_b_f1 76.07 0.23
rf_b_acc** 84.55 0.22
ab_f1 54.38 0.95
ab_acc 63.62 0.68
ab_b_f1 73.35 0.56
ab_b_acc 80.02 0.44
lda_f1 65.31 -
lda_acc* 71.63 -
lda_b_f1 86.07 -
lda_b_acc* 89.03 -

* Best model in terms of accuracy

** Runner-up

  1. Evaluation scores using physiological modalities:
mean std
rf_f1 60.97 0.93
rf_acc** 71.07 0.36
rf_b_f1 78.58 0.61
rf_b_acc** 85.52 0.47
ab_f1 59.65 1.12
ab_acc 67.47 0.97
ab_b_f1 77.17 0.44
ab_b_acc 82.89 0.47
lda_f1 66.62 -
lda_acc* 74.02 -
lda_b_f1 86.43 -
lda_b_acc* 89.86 -
  • For a more in-depth analysis of results for (2) & (3) check the notebook ML Classifiers - Chest Device.ipynb

  • Feature importance on the Three-class classification: baseline vs stress vs amusement

idx feature imp
64 RESP_exhal_mean 0.239672
36 EDA_SCR_no 0.133317
15 ECG_hr_mean 0.106798
56 EMG_peak_amp_sum 0.0847333
5 ACC_xyz_std 0.0697695
74 TEMP_min 0.0576274
46 EDA_std 0.0369737
58 EMG_peak_no 0.0243881
6 ACC_xzy_mean 0.0238573
1 ACC_x_mean 0.0235114
  • Feature importance on the Binary classification: stress vs non-stress
idx feature imp
64 RESP_exhal_mean 0.395155
15 ECG_hr_mean 0.157471
36 EDA_SCR_no 0.139167
72 TEMP_max 0.0479302
0 ACC_x_absint 0.042426
58 EMG_peak_no 0.0381359
44 EDA_scr_area 0.0348049
65 RESP_exhal_std 0.023892
56 EMG_peak_amp_sum 0.0164472
8 ACC_y_mean 0.0162326

Wrist-worn device

  • WIP