Polynomial Time 2-Approximation Algorithms for the Minmax Subtree Cover Problem. - Hiroshi Nagamochi; Kohei Okada (ISAAC, 2003)

A faster 2-approximation algorithm for the minmax p-traveling salesmen problem on a tree. - Hiroshi Nagamochi; Kohei Okada (Discret. Appl. Math., 2004)

New Optical VPN Configuration using Wavelength Routers in a WDM-Passive Optical Network. - Kimio Oguchi; Kohei Okada; Shohei Terada; Kunio Tojo (ICCCN, 2007)

Approximating the minmax rooted-tree cover in a tree. - Hiroshi Nagamochi; Kohei Okada (Inf. Process. Lett., 2007)

Size effect on crack propagation of nano-scale silicon with different type of nothes. - Kohei Okada; Shinya Nakamura; Masahiro Nakajima; Taeko Ando (MHS, 2017)

In-Situ Observation of Fracture Behavior of Silicon in a Transmission Electron Microscope. - Kohei Okada; Syugo Tanaka; Kensuke Nakata; Masahiro Nakajima; Taeko Ando (MHS, 2018)