Research Article

Adaptive Online Sequential ELM for Concept Drift Tackling

Table 5

Average testing accuracy and Cohen’s kappa in % for MNIST RD, HD, and MNIST + USPS transfer learning experiment (other ELM parameters are same: ROS, , , ) with 10x trials.
(a) Benchmark result, nonadaptive OS-ELM and offline ELM

SourceClassTesting accuracyCohen’s kappa
OS-ELMOffline ELMOS-ELMOffline ELM

MNIST (1–6)95.99 ± 0.1596.00 ± 0.1495.21 (0.30)95.22 (0.30)
(7–10)94.30 ± 0.2294.32 ± 0.1992.50 (0.48)92.53 (0.48)

MNIST (1–6)97.59 ± 0.1197.49 ± 0.0997.10 (0.23)97.00 (0.24)
(7–10)95.76 ± 0.2695.87 ± 0.1294.40 (0.42)94.55 (0.42)

MNIST + USPS (1–10)96.01 ± 0.1096.08 ± 0.0895.56 (0.02)95.65 (0.02)
(A–Z)99.94 ± 0.0299.94 ± 0.0299.94 (0.02)99.93 (0.02)

(b) RD experiment, ELM ensemble (3 classifiers, full memory) versus AOS-ELM

SourceConceptTesting accuracyCohen’s kappa
ELM ensembleAOS-ELMELM ensembleAOS-ELM

MNIST  (1–6)94.58 ± 0.1796.09 ± 0.1293.54 (0.35)95.10 (0.31)
(7–10)91.60 ± 0.2994.34 ± 0.1689.04 (0.57)92.56 (0.48)

(c) HD experiment, ELM ensemble (3 classifiers, full memory, outdated classifier pruning) versus AOS-ELM

SourceConceptTesting accuracyCohen’s kappa
ELM ensembleAOS-ELMELM ensembleAOS-ELM

MNIST  (1–6)94.48 ± 0.3397.01 ± 0.1893.42 (0.35)96.42 (0.26)
MNIST  (7–10)92.29 ± 0.3696.05 ± 0.1989.95 (0.55)94.78 (0.40)

(d) MNIST + USPS experiment, ELM ensemble (5 classifiers, full memory, outdated classifier pruning) versus AOS-ELM

SourceConceptTesting accuracyCohen’s kappa
ELM ensembleAOS-ELMELM ensembleAOS-ELM

MNIST  (1–10)88.17 ± 11.0695.91 ± 0.1286.94 (0.33)95.46 (0.22)
USPS  (A–Z)99.80 ± 0.0599.95 ± 0.0399.79 (0.40)99.95 (0.02)