Topology-Guided Path Integral Approach for Stochastic Optimal Control in Cluttered Environment

This paper addresses planning and control of robot motion under uncertainty that is formulated as a continuous-time, continuous-space stochastic optimal control problem, by developing a topology-guided path integral control method. The path integral control framework, which forms the backbone of the proposed method, re-writes the Hamilton-Jacobi-Bellman equation as a statistical inference problem; the resulting inference problem is solved by a sampling procedure that computes the distribution of controlled trajectories around the trajectory by the passive dynamics. For motion control of robots in a highly cluttered environment, however, this sampling can easily be trapped in a local minimum unless the sample size is very large, since the global optimality of local minima depends on the degree of uncertainty. Thus, a homology-embedded sampling-based planner that identifies many (potentially) local-minimum trajectories in different homology classes is developed to aid the sampling process. In combination with a receding-horizon fashion of the optimal control the proposed method produces a dynamically feasible and collision-free motion plans without being trapped in a local minimum. Numerical examples on a synthetic toy problem and on quadrotor control in a complex obstacle field demonstrate the validity of the proposed method.Comment: arXiv admin note: text overlap with arXiv:1510.0534

Scientific Evidence for Korean Medicine and Its Integrative Medical Research 2017

In 2016, the total medical fee for Korea Medicine (KM) in South Korea was over 4 billion dollars and the National Health Insurance of South Korea paid about 2.09 billion dollars for medical services provided by 19, 737 KM doctors in 302 KM hospitals and 14, 150 KM local clinics. Actually, 12.9 million Korean patients received 105 million outpatient services provided by KM doctors in 2016. The older the Korean society is, the more important the role of KM becomes, because Korea is anticipated to be a hyperaged society in 2028. As well as the Donguibogam, which was enlisted on the Memory of the Word by UNESCO in 2009, Sasang typology, Sasang Constitutional Medicine, Sa-am acupuncture, Chuna therapy, Pharmacopuncture, Korean physical therapy, Korean psychotherapy, and so on characterize KM. But more integrative researches and scientific evidences for KM might strengthen both clinical efficacy and applicability of KM. In this respect, it seems to be unavoidable that KM utilizes cutting-edge techniques of modern science. The more accurate and efficient practice of KM innovated with the modern bioscientific technology would help people live healthy lives. Our special issue, which had opened for 6 months in the first half of 2017, focused on scientific evidence for KM and its integrative medical research