Ji Yeong Lee

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Coverage path planning determines a path that passes a robot, a detector, or some type of effector over all points in the environment. Prior work in coverage tends to fall into one of two extremes: coverage with an effector the same size of the robot, and coverage with an effector that has infinite range. In this paper, we consider coverage in the middle of(More)
Kainic acid (KA) induced oxidative stress is associated with hippocampal cell death. Recent studies suggest that curcumin, a potent antioxidant, may provide protection for KA-induced oxidative stress. We investigated the effects of curcumin treatment on hippocampal reactive astrocytes in mice with KA-induced seizures. Eighteen hours after curcumin(More)
We have introduced both electrophoretic and dynamic light scattering to evaluate the polydispersity, nanodispersity, and stability of single-walled carbon nanotubes (SWNTs) in distilled water with surfactants. By controlling the sodium dodecyl sulfate composition and some pretreatment by sonication, we were able to achieve nanodispersion (dispersion into(More)
Implantation of an embryo occurs during the mid-secretory phase of the menstrual cycle, known as the "implantation window." During this implantation period, there are significant morphologic and functional changes in the endometrium, which is followed by decidualization. Many immune cells, such as dendritic and natural killer (NK) cells, increase in number(More)
The absorption and dispersion of aligned single-walled carbon-nanotube films were measured from 0.2 to 2.0 THz using a source of freely propagating subpicosecond pulses of THz electromagnetic radiation. The real conductivity increased rapidly with increasing frequency up to 0.45 THz and decreased at a high-frequency range. The Maxwell–Garnett model, where(More)
Kainic acid (KA)-induced seizure induces the hippocampal cell death. There are reports that AMP-activated protein kinase (AMPK), which is an important regulator of energy homeostasis of cells, has been proposed as apoptotic molecule. In this study, we investigated the altered expression of AMPK cascade in the hippocampus of mice during KA-induced(More)
Sensor-based planning for rod-shaped robots is necessary for the realistic deployment of noncircularly symmetric robots into unknown environments. Whereas circularly symmetric robots have two-dimensional Euclidean configuration spaces, planar rod robots posses three degrees-of-freedom, two for position and one for orientation, and hence have a(More)
The need for an intelligent transport system has been heightened in the present day, by the ever-growing demand to combine ease of transport with maximum efficacy. The Segway robot provides a platform which balances itself and transports the user in accordance to its natural lean. However in order to achieve a truly intelligent system, challenges(More)
We present a new roadmap that can be used to guide a convex body to explore an unknown planar workspace, i.e., to map an unknown configuration space diffeomorphic to SE(2). This new roadmap is called the convex hierarchical generalized Voronoi graph (convex-HGVG). Since this roadmap is defined in terms of workspace distance information that is within line(More)
In this paper, we propose and experimentally test a dynamic model-based force controller for the motion of upper limb exoskeleton robot. The system is composed of 3 degrees of freedom using an electrical actuator. This system is mainly controlled by the multi-axis force sensor signals. These are used to generate desired torques for driving the robot system.(More)