About the Authors

No-Sang Kwak

Affiliation Department of Brain and Cognitive Engineering, Korea University, Anam-dong, Seongbuk-ku, Seoul, Republic of Korea

Klaus-Robert Müller

Affiliations Department of Brain and Cognitive Engineering, Korea University, Anam-dong, Seongbuk-ku, Seoul, Republic of Korea, Department of Computer Science, TU Berlin, Berlin, Germany

Seong-Whan Lee

sw.lee@korea.ac.kr

Affiliation Department of Brain and Cognitive Engineering, Korea University, Anam-dong, Seongbuk-ku, Seoul, Republic of Korea

Competing Interests

The authors would like to clarify that Samsung Research Funding Center of Samsung Electronics, the funder of this study, had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Also, there are no patents, products in development or marketed products to declare. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Author Contributions

Formal analysis: NSK. Investigation: NSK. Methodology: NSK KRM SWL. Project administration: SWL. Supervision: SWL. Validation: KRM. Visualization: NSK. Writing – original draft: NSK KRM SWL. Writing – review & editing: NSK KRM SWL.