• International Journal of Fuzzy Logic and Intelligent Systems
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• 제10권3호
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• pp.203-209
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• 2010

This paper presents a hierarchical fuzzy motion planner for humanoid robots in 3D uneven environments. First, we define both motion primitives and locomotion primitives of humanoid robots. A high-level planner finds a global path from a global navigation map that is generated based on a combination of 2.5 dimensional maps of the workspace. We use a passage map, an obstacle map and a gradient map of obstacles to distinguish obstacles. A mid-level planner creates subgoals that help the robot efficiently cope with various obstacles using only a small set of locomotion primitives that are useful for stable navigation of the robot. We use a local obstacle map to find the subgoals along the global path. A low-level planner searches for an optimal sequence of locomotion primitives between subgoals by using fuzzy motion planning. We verify our approach on a virtual humanoid robot in a simulated environment. Simulation results show a reduction in planning time and the feasibility of the proposed method.

• 로봇학회논문지
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• 제14권2호
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• pp.104-113
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• 2019

Object manipulation in cluttered environments remains an open hard problem. In cluttered environments, grasping objects often fails for various reasons. This paper proposes a novel task and motion planning scheme to grasp objects obstructed by other objects in cluttered environments. Task and motion planning (TAMP) aims to generate a sequence of task-level actions where its feasibility is verified in the motion space. The proposed scheme contains an open-loop consisting of three distinct phases: 1) Generation of a task-level skeleton plan with pose references, 2) Instantiation of pose references by motion-level search, and 3) Re-planning task based on the updated state description. By conducting experiments with simulated robots, we show the high efficiency of our scheme.

• 해양환경안전학회지
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• 제29권7호
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• pp.958-963
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• 2023

최근에 선박을 안전하게 설계 및 운항하기 위해 인공지능으로 운동성능을 예측하는 연구가 늘고 있다. 하지만 일반적인 선박에 비해 소형 어선에 대한 연구는 부족한 실정이다. 본 논문에서는 소형 어선의 운동성능 계산에 필수적인 운동응답을 심층신경망으로 추정하는 모델을 제안한다. 15척의 소형 어선에 대하여 유체동역학 해석을 수행하였으며 이를 통해 데이터베이스를 구축하였다. 환경 조건과 주요 제원을 입력 데이터로, 단위 파고에 대한 운동응답(Response Amplitude Operator)을 출력 데이터로 설정하였다. 훈련된 심층신경망 모델을 통해 예측된 운동응답은 유체동역학 해석 결과와 유사한 경향을 보이며 고주파 성분을 가진 운동응답 함수를 낮은 오차로 근사하는 결과를 보여준다. 본 연구의 결과를 바탕으로 어선의 선형 특성 고려한 심층신경망 모델로 확장하여 연구 결과의 활용도를 넓히고자 한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.285-288
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• 2008

In ubiquitous computing environment the biological signal ECG (Electrocardiogram signal) is usually recorded with noise components. Adaptive interference (or noise) canceller do adaptive filtering of the noise reference input to maximally match and subtract out noise or interference from the primary (signal plus noise) input thereby adaptively eliminate unwanted interference from the ECG signal. Measured Stress ECG (or exercise ECG signal) signal have three major noisy component like baseline wander noise, motion artifact noise and EMG (Electro-mayo-cardiogram) noise. These noises are not only distorted signal but also root of incorrect diagnosis while ECG data are analyzed. Motion artifact and EMG noises behave like wide band spectrum signals, and they considerably do overlapping with the ECG spectrum. Here the multidimensional adaptive method used for filtering which is more effective to improve signal to noise ratio.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 1부
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• pp.993-998
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• 2006

본 논문은 기존의 휴대폰과 같은 모바일 환경에서의 제약적인 화면을 극복하기 위하여 가상의 스크린을 만들고 이를 사용자가 손쉽게 제어할 수 있는 인터페이스에 대해서 제안하였다. 기존의 방법은 버튼을 반복적으로 눌러 스크롤 했던 것에 반해 제안된 인터페이스는 휴대폰 카메라를 통해 입력되는 영상 신호를 기반으로 움직임 벡터 값을 추출하고 이를 통하여 사용자가 움직이는 방향대로 화면을 움직여 줌으로서 사용자에게 편리하고 직관적인 인터페이스를 제공함으로서 휴대폰의 제한적인 화면을 극복 하였다. 모바일 환경에서의 움직임 벡터 값을 추출하기 위한 알고리즘을 제안하고, 제한적인 화면으로 인하여 정보 표현에 한계가 있던 점을 극복하여 모바일 환경에서의 새로운 인터페이스를 제안하였다.

• 한국산업융합학회 논문집
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• 제17권2호
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• pp.35-41
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• 2014

This paper describes the obstacle avoidance architecture to walk safely around in factory and home environment, and presents methods for path planning and obstacle avoidance for the humanoid robot. Solving the problem of obstacle avoidance for a humanoid robot in an unstructured environment is a big challenge, because the robot can easily lose its stability or fall down if it hits or steps on an obstacle. We briefly overview the general software architecture composed of perception, short and long term memory, behavior control, and motion control, and emphasize on our methods for obstacle detection by plane extraction, occupancy grid mapping, and path planning. A main technological target is to autonomously explore and wander around in home environments as well as to communicate with humans.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.120.1-120
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• 2001

This paper proposes a prototype of a safe and reliable wheelchair robot with Human Robot Interaction (HRI). Since the wheelchair users are usually the handicapped, the wheelchair robot must guarantee the safety and reliability for the motion while considering users intention, A single color CCD camera is mounted for input user´s command based on human-friendly gestures, and a ultra sonic sensor array is used for sensing external motion environment. We use face and hand directional gestures as the user´s command. By combining the user´s command with the sensed environment configuration, the planner of the wheelchair robot selects an optimal motion. We implement a prototype wheelchair robot, MR, HURI (Mobile Robot with Human Robot Interaction) ...

• 제어로봇시스템학회논문지
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• 제16권4호
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• pp.361-367
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• 2010

This paper reports the development of a mobile robot for patrol using a single laser range finder. A Laser range finder is useful for outdoor environment regardless of illumination change or various weather conditions. In this paper we combined the motion control of the mobile robot and the algorithm for detecting the outdoor environment. For obstacle avoidance, we adopted the Vector Field Histogram algorithm. A laser range finder is mounted on the mobile robot and looking down the road with a small tilt angle. We propose an algorithm for detecting the surface of the road. The outdoor patrol robot platform is equipped with a DGPS system, a gyro-compass sensor, and a laser range finder. The proposed obstacle avoidance and road detection algorithms were experimentally tested in success.

• Structural Engineering and Mechanics
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• 제88권5호
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• pp.405-417
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• 2023

This paper reveals theoretical research to the nonlinear dynamic response and initial geometric imperfections sensitivity of the spinning graphene platelets reinforced metal foams (GPLRMF) cylindrical shell under different boundary conditions in thermal environment. For the theoretical research, with the framework of von-Karman geometric nonlinearity, the GPLRMF cylindrical shell model which involves Coriolis acceleration and centrifugal acceleration caused by spinning motion is assumed to undergo large deformations. The coupled governing equations of motion are deduced using Euler-Lagrange principle and then solved by a combination of Galerkin's technique and modified Lindstedt Poincare (MLP) model. Furthermore, the impacts of a set of parameters including spinning velocity, initial geometric imperfections, temperature variation, weight fraction of GPLs, GPLs distribution pattern, porosity distribution pattern, porosity coefficient and external excitation amplitude on the nonlinear harmonic resonances of the spinning GPLRMF cylindrical shells are presented.

• 한국통신학회논문지
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• 제22권6호
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• pp.1343-1355
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• 1997

Full motion video data is the most effective data type that transmits information in multimedia enviornment. VOD service is system that uses network to transmit full motion video data interactively. Therefore VOD service system must satisfy the following requirements. First, it should transmit high quality full motion video. Second, it should be able to control a large quantity of full motion video. Third, a user should be able to retrieve the full motion vide effectively. However the existing VOD service system is established based n file system that not only does it have disadvantages in managment such as transaction control but also it is not suitable for distributed multimedia environment. The goal of this research is to build a VOD service system that provides high-quality full motion video assuming information retrieval. In order to mainly search video data's bibliographical information and to manage related information, VOD service system and DBMS system are to be closely related. Also, to transmit high quality full motion video data, we use MTP$^{TM}$(Media Transfer Protocol) developed by StarLight. MTP$^{TM}$ guarantees high bandwidth that is necessary to tansmit high quality full motion video data effectively. In other hand TCP/IP which is used for information search does not guarentee high bandwidth as that in MTP$^{TM}$. Therfore VOD service system that seraches information managed by DBMS and transmits requried full motion video data should control different kinds of protocol simultaneously. This paper describes the configuration of VODB system that has solved these problems, implementation and efficiency of data applied system.stem.