Time-varying data processing with nonvolatile memristor-based temporal kernel

Recent advances in a physical reservoir, which is a type of temporal kernel, have made it possible to perform complicated timing-related tasks using a linear classifier. However, the fixed reservoir dynamics in previous studies have limited application fields. In this study, temporal kernel (TK) computing was implemented with a physical kernel that consisted of a W/HfO2/TiN memristor (M), a capacitor (C), and a resistor (R), in which the kernel dynamics could be arbitrarily controlled by changing their parameters. After the capability of the TK to identify the static MNIST data was proven, the system was adopted to recognize the sequential data [ultrasound (malignancy of lesions) and electrocardiogram (arrhythmia)] that had a significantly different time constant (10 7 vs 1 s). The suggested system feasibly performed the task by simply varying the C and R. These functionalities demonstrate the high adaptability of the present TK system compared to the previous ones. 

Cheol Seong Hwang received an M.Sc degree in 1989 and a Ph.D. degree in 1993 in the department of inorganic materials science and engineering, both from Seoul National University-Seoul, South Korea. In 1993, he joined the Materials Science and Engineering Laboratory of National Institute of Standards and Technology, MD USA, as a postdoctoral research fellow. Then, he joined Samsung Electronics as a senior researcher from 1994, made contributions to the fields of semiconductor memory devices by researching high-k dielectrics including (Ba,Sr)TiO3. Since 1998, he has been a professor in the Department of Materials Science and Engineering at Seoul National University. He has authored or co-authored more than 653 papers in international peer-reviewed scientific journals, which are cited ~33,500 times each (H-index 89), has given over 100 invited presentations at international conferences. He also holds ~130 international/domestic patents. He is a recipient of Alexander von Humboldt fellowship award, which made him stay in Forschungszentrum Juelich,, Germany as a Humboldt fellow in 2004, the 7th presidential young scientist award of the Korean government, and AP faculty Excellence Award, Air Products, USA, Inchon award, and Kyung-Ahm award. His current interests include high K gate oxide, DRAM capacitors, new memory devices including RRAM?PRAM, ferroelectric materials and devices, negative capacitance effect, and thin film transistors. He is also working actively in the field of neuromorphoric computing devices/materials. He served as the general chair of the International ALD Conference in June 2010, in Seoul, Korea. He also authored books entitled "Atomic Layer Deposition for Semiconductor" in 2013 through Springer, and "Ferroelectricity in doped hafnium oxide" in 2019 through Elsevier. He is a member of the Korean Academy of Science and Technology, National Academy of Engineering of Korea, and a fellow of the Royal Society of Chemistry, UK. On September 1, 2020, he was selected as the Seoul National University (SNU) Distinguished professor, which is awarded to only eight members among the ~2200 SNU professors.