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Mobile robot navigation using grid line patterns via probabilistic measurement modeling
Kim, Taeyun,Kim, Jinwhan,Choi, Hyun-Taek Springer-Verlag 2016 INTELLIGENT SERVICE ROBOTICS Vol.9 No.2
<P>Mobile robots are generally equipped with proprioceptive motion sensors such as odometers and inertial sensors. These sensors are used for dead-reckoning navigation in an indoor environment where GPS is not available. However, this dead-reckoning scheme is susceptible to drift error in position and heading. This study proposes using grid line patterns which are often found on the surface of floors or ceilings in an indoor environment to obtain pose (i.e., position and orientation) fix information without additional external position information by artificial beacons or landmarks. The grid lines can provide relative pose information of a robot with respect to the grid structure and thus can be used to correct the pose estimation errors. However, grid line patterns are repetitive in nature, which leads to difficulties in estimating its configuration and structure using conventional Gaussian filtering that represent the system uncertainty using a unimodal function (e.g., Kalman filter). In this study, a probabilistic sensor model to deal with multiple hypotheses is employed and an online navigation filter is designed in the framework of particle filtering. To demonstrate the performance of the proposed approach, an experiment was performed in an indoor environment using a wheeled mobile robot, and the results are presented.</P>
Coordinated weathervaning control of two surface vessels in a tandem configuration
Kim, Young-Shik,Lee, Hyungbae,Kim, Jinwhan Elsevier 2017 Ocean engineering Vol.130 No.-
<P><B>Abstract</B></P> <P>During a tandem offloading operation between a floating production storage and offloading (FPSO) unit and a connected shuttle tanker (ST), the control of the relative position and heading between two vessels is crucially important, since large relative motion may cause serious accidents such as collision or hose disconnection. Dynamic positioning (DP) systems can be used to control the motion of the vessels during the operation. Among various DP control strategies, weathervaning control enables each vessel to be oriented toward the direction of the mean environmental force induced by wind, wave and ocean current so as to improve the operational safety and reduce the overall thruster power consumption. This study proposes a controller design for DP in the task space of the vehicle dynamics that allows for weathervaning control without explicit measurements or accurate estimation of environmental disturbances. A coordinated control scheme assuming a reliable communication channel between two vessels is also introduced to ensure the safety of the vessels and continuous oil transfer by suppressing excessive relative heading changes under significant environmental disturbances. Numerical simulation results for several DP control scenarios under different control settings and environmental conditions are presented.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A control algorithm for dynamic positioning of two vessels in tandem is presented. </LI> <LI> Unlike conventional controllers, our controller is designed in the task space. </LI> <LI> Weathervaning control is performed without explicit disturbance observations. </LI> <LI> Coordinated control is considered to suppress relative motion and improve safety. </LI> <LI> Numerical simulation results confirmed the performance of the proposed approach. </LI> </UL> </P>
An Optimal Control Formulation for Dual Control Problems
Jinwhan Kim,Sungmoon Joo 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10
A systematic procedure is introduced, which allows converting a stochastic control problem involving a tradeoff between minimizing control effort and maximizing estimation performance into a deterministic two-point boundary value problem. The proposed approach can be applied to calculating control inputs for a system whose observability is affected by the system’s state trajectory due to nonlinear coupling between estimation and control, called the dual effect. A parameter estimation problem is considered in order to demonstrate the feasibility of the proposed approach. The parameter estimation problem is formulated as a nonlinear two-point boundary problem and then solved numerically using a collocation method.
Modeling Air-Traffic Service Time Uncertainties for Queuing Network Analysis
Jinwhan Kim,Tandale, M.,Menon, P. K. IEEE 2012 IEEE transactions on aerospace and electronic syst Vol.48 No.1
<P>Numerous factors influence the operational performance of the National Airspace System (NAS). In particular, the traffic efficiency is affected by uncertainties such as weather, navigation accuracy, aircraft performance and operational procedures, and air traffic management (ATM) actions. This study focuses on identifying various air traffic uncertainty sources and deriving the associated mathematical models of service time distributions. These models provide the distributions given air traffic uncertainties through analytical expressions without resorting to computationally expensive Monte-Carlo simulations.</P>
시불변 불균일 스칼라장에서의 항법을 위한 실시간 필터 알고리듬
김진환(Jinwhan Kim) 대한조선학회 2011 대한조선학회 학술대회자료집 Vol.2011 No.6
An algorithm for localization and navigation using a series of point measurements in a time-invariant non-uniform scalar field whose distribution is known in advance is presented in this research. For point measurements, various scalar physical quantities can be considered such as temperature, density, salinity, intensity of light or an electromagnetic field, etc. A spatial distribution of these physical quantities forms a field map which enables map-based navigation for a vehicle. The filter formulation for this field map-based navigation leads to a nonlinear estimation problem. Several nonlinear estimation techniques including the extended Kalman filter and the pariticle filter are considered in this research. In addition, the feasibility of using a Rao-Blackwellized particle filter is examined and its performance is demonstrated through numerical simulations in a synthetic scalar field.
LuckyViewPicks: 기념일을 위한 운세기반 영화 추천
김진환(Jinwhan Kim),이태일(Taeil Lee) 한국HCI학회 2024 한국HCI학회 학술대회 Vol.2024 No.1
본 논문에서는 기념일에 대한 운세와 영화, 두 콘텐츠를 색다른 방식으로 체험할 수 있는 인터랙션 방안을 소개한다. 작품의 테마는 매년 가장 중요하게 여기는 기념일 중 하나인 크리스마스로 선정하였다. 지인들과 크리스마스카드 주고받기는 오래된 아날로그식 관례이자 동심을 유발하는 매체이다. 이를 모티브로 하여 관람객과 디지털 환경의 매개체가 될 실물 카드를 제작하였다. 이후, 웹 베이스의 머신러닝 도구인 티처블 머신을 활용해 이미지 학습, 모델을 생성한 뒤 화면상에서 운세를 확인할 수 있게 하였다. 연결된 두 요소는 데이터셋과 다시 연동되어 788 편의 크리스마스 영화 중 해당하는 운세의 내용과 유사한 장르의 영화 데이터를 매핑, 추천하도록 시각화하였다. 본 작품은 그날의 운세 뽑기와 동시에 영화를 추천받아 마치 크리스마스카드가 영화 티켓의 역할을 하는 듯한 인터랙션 경험을 통해 크리스마스를 한층 즐겁게 보낼 수 있도록 돕는다.