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        검색결과 223

        202.
        2010.05 KCI 등재 서비스 종료(열람 제한)
        This paper aims to add the autonomous driving capability to the inverted pendulum system which maintains the inverted pendulum upright stably. For the autonomous driving from the starting position to the goal position, the motion control algorithm is proposed based on the dynamics of the inverted pendulum robot. To derive the dynamic model of the inverted pendulum robot, a three dimensional robot coordinate is defined and the velocity jacobian is newly derived. With the analysis of the wheel rolling motion, the dynamics of inverted pendulum robot are derived and used for the motion control algorithm. To maintain the balance of the inverted pendulum, the autonomous driving strategy is derived step by step considering the acceleration, constant velocity and deceleration states simultaneously. The driving experiments of inverted pendulum robot are performed while maintaining the balance of the inverted pendulum. For reading the positions of the inverted pendulum and wheels, only the encoders are utilized to make the system cheap and reliable. Even though the derived dynamics works for the slanted surface, the experiments are carried out in the standardized flat ground using the inverted pendulum robot in this paper. The experimental data for the wheel rolling and inverted pendulum motions are demonstrated for the straight line motion from a start position to the goal position.
        203.
        2010.02 KCI 등재 서비스 종료(열람 제한)
        This paper proposes the technique of estimating the pipe thickness using the measured group velocity. To measure the group velocity from the accelerometer data in the frequency domain, Wigner-Ville distribution is utilized, which interprets the waveform of the shock wave. Using this measured group velocity, this paper proposes the technique to estimate the thickness of pipes with the impact on the pipe. The group velocity is estimated by the modeling correlation between the group velocity and the thickness of the pipe based on the propagation velocities. The correlation model between thickness and group velocity has been proved through the real experiments. The measured group velocity in the frequency-domain is the maximum at the center frequency of the bending waves in the modeling of the group velocity. In addition to these, a smoothing technique for analyzing lamb wave Wigner-Ville distribution has been introduced to improve the reliability of the data acquisition.
        204.
        2009.11 KCI 등재 서비스 종료(열람 제한)
        This paper proposed a new magnetic field detection algorithm to detect metal pieces in food producing processes. This algorithm can detect mixed metal pieces by sensing magnetic field. Some metal pieces are passed through an over-current circuit to magnetize them. The magnetic field sensor can detect the change in the magnetic field on the conveyor belt caused by the flow of the metal pieces in the food product. However, such a method detects the output of signals that change their amplitude and phase according to the movement of the conveyor belt with the food product, in which the equilibrium of the positive signal that is created in the receiver coil loses its balance due to the magnetized material. This includes not only the signal elements resulting from the effect of the alternating magnetic fields of the mixed metals, but also the signal elements resulting from the effect of the alternating magnetic fields of the examined object itself.
        206.
        2009.03 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 지식공유와 지식관리시스템에 관한 이론과 선행연구를 통하여 해운 항만 공공부문과 해운기업을 대상으로 지식관리시스템 사용과 지식공유 의도에 영향을 주는 요인들을 추출하여 그 요인들의 상호 영향관계를 살펴보았다. 총 7개의 가설을 검증한 결과, 먼저 지식공유 의도의 영향요인들 중에서 최고 경영층의 지원, 자기 가치감, 신뢰가 지식공유 의도에 영향을 미치는 것으로 확인되었고, 또한 보상제도와 지식관리시스템의 사용과 관계, 지식공유 의도와 지식관리시스템 사용과의 관계 통계적으로 유의한 결과로 나타났다. 본 연구 결과는 앞으로 지식관리시스템 사용과 관련된 연구에 있어서 지식공유 의도의 영향력에 대학 실증적 근거로 제시될 수 있을 것이다. 또한 지식관리 시스템을 도입 사용하고 있는 기업의 실무자들에게 현재 자신들의 지식관리시스템 사용 현황을 재진단하고 문제점을 짚어봄으로써 향후 지식관리시스템을 통한 지식공유를 촉진하기 위한 방안을 모색하는데 기초 자료로 활용될 수 있을 것이다.
        207.
        2008.11 KCI 등재 서비스 종료(열람 제한)
        The field of robots is being widely accepted as a new technology today. Many robots are produced continuously to impart amusement to people. Especially the robot which operates with a wheelbarrow was enough of a work of art to arouse excitement in the audiences. All the wheelbarrow robots share the same technology in that the direction of roll and pitch are acting as balance controllers, allowing the robots to maintain balance for a long period by continuously moving forward and backward. However one disadvantage of this technology is that they cannot avoid obstacles in their way. Therefore movement in sideways is a necessity. For the control of rotation of yawing direction, the angle and direction of rotation are adjusted according to the velocity and torque of rotation of a motor. Therefore this study aimed to inquire into controlling yawing direction, which is responsible for rotation of a robot. This was followed by creating a simulation of a wheelbarrow robot and equipping the robot with a yawing direction controlling device in the center of the body so as to allow sideway movements.
        208.
        2008.11 KCI 등재 서비스 종료(열람 제한)
        The development of a face robot basically targets very natural human-robot interaction (HRI), especially emotional interaction. So does a face robot introduced in this paper, named Buddy. Since Buddy was developed for a mobile service robot, it doesn’t have a living-being like face such as human’s or animal’s, but a typically robot-like face with hard skin, which maybe suitable for mass production. Besides, its structure and mechanism should be simple and its production cost low. This paper introduces the mechanisms and functions of mobile face robot named Buddy which can take on natural and precise facial expressions and make dynamic gestures driven by one laptop PC. Buddy also can perform lip-sync, eye-contact, face-tracking for lifelike interaction. In addition, by adopting a customized emotional reaction decision model, Buddy can create own personality, emotion and motive using various sensor data input. Based on this model, Buddy can interact probably with users and perform real-time learning using personality factors. The interaction performance of Buddy is successfully demonstrated by experiments and simulations.
        209.
        2008.08 KCI 등재 서비스 종료(열람 제한)
        최근 컨테이너터미널 간의 경쟁이 심화되면서 생산성 측면뿐 만 아니라 비용경제성 측면에도 관심이 부각되고 있다. 특히, 에너지 소모량 및 장비투입 규모가 큰 트랜스퍼 크레인 부문에 대한 비효율적인 작업요소가 컨테이너터미널 경쟁력 제고에 있어서 걸림돌이 되고 있으며 이에 대한 개선은 인적, 물적 운영비용의 절감과 함께 생산성의 향상에도 긍정적인 영향을 미칠 것으로 기대된다. 따라서 본 연구에서는 현재 국토해양부 주관으로 진행 중인 'RFID를 활용한 RTLS 기반 항만물류효율화 사업'을 통하여 제공 가능한 컨테이너터미널 반 출입 대상 컨테이너의 시간적 가시성을 토대의 트랜스퍼 크레인의 배정 및 이동경로에 대한 클러스터링 기반 최적화모델을 제안하고 시뮬레이션 기법을 통하여 기대효과수준을 확인하였다.
        210.
        2008.06 KCI 등재 서비스 종료(열람 제한)
        최근 컨테이너선의 대형화 추세와 항만간의 경쟁 가속화로 인해 컨테이너터미널의 효율적 운영과 생산성 향상에 대한 관심과 노력이 증대되고 있다. 특히 YT를 이용한 이송방식을 채택하고 있는 터미널의 경우 AGV(Automated Guided Vehicle)를 이용하고 있는 자동화터미널에 비해 상대적으로 경제성 및 운용효율성 측면에서 불리한 것이 사실이다. 최근 10여 년간 이와 같은 YT운용의 비효율성을 보완하기 위해 YT Pooling Operation 도입과 같은 노력이 계속되어 왔으나 개별 YT의 위치인식기능부재로 인한 제약으로 실질적인 효과는 미미한 수준이었다. 본 연구에서는 최근 주목받고 있는 RTLS(Real Time Location System) 기술을 활용하여 기존 YT Pooling Operation의 제약사항을 해결하는 새로운 개념의 YT Dynamic Operation 모델을 세안한다.
        211.
        2007.10 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 해운회사와 컨테이너터미널 간 전자적 정보공유를 촉진하고 활성화하는 요인들을 관련 이론 및 선행연구를 통해 추출하고 실증적으로 검증해 보는 것과 해운회사와 컨테이너터미널 간 전자적 정보공유의 정도가 성과에 어떠한 영향을 미치는 지를 해운회사의 입장에서 실증연구를 통해 규명해 보고자 하는 것을 목적으로 하였다. 연구 결과 첫째, 전자적 정보공유의 결정요인으로 최고경영자의 지원정도, 정보기술 인프라수준, 몰입, 의존성이 통계적으로 유의한 결과를 나타냄으로써 이러한 요인들이 해운회사와 컨테이너터미널 간의 전자적 정보공유에 영향을 미치는 것으로 검증된 반면, 신뢰는 전자적 정보공유에 유의한 영향을 미치지 않는 것으로 확인되었다. 둘째, 해운회사와 컨테이너터미널 간의 전자적 정보공유가 성과에 유의한 영향을 미치는 것으로 나타났다.
        212.
        2007.09 KCI 등재 서비스 종료(열람 제한)
        우리나라 유치원은 시설, 교사, 교육과정, 교육환경 등 유치원 운영 전반에 대하여 유아교육법, 사립학교법, 학교보건법, 재무회계규칙 등 법적 규정이 적용됨으로써 기본적인 질 관리가 이루어지고 있다. 특히, 사립유치원에 대한 설립인가제 적용과 시․도교육청별 장학지도 실시는 유치원의 질을 관리․유지하는 중요한 기제가 되고 있다. 그러나 유치원이 학교로서 보다 질 높은 프로그램을 제공하고, 국가 정책에 부합하는 유치원 운영관리를 강화하기 위해서는 국가수준의 유치원 평가가 요구된다. 여기서는 현재 우리나라의 유치원 질 관리 현황을 살펴보고, 향후 유치원 평가의 추진 방향과 과제를 제시하고자 한다.
        213.
        2007.09 KCI 등재 서비스 종료(열람 제한)
        A robust position-sensing system is proposed in this paper for ubiquitous mobile robots which move indoor as well as outdoor. The Differential GPS (DGPS) which has position estimation error of less than 5 m is a general solution when the mobile robots are moving outdoor, while an active beacon system (ABS) with embedded ultrasonic sensors is selected as an indoor positioning system. The switching from the outdoor to indoor or vice versa causes unstable measurements on account of the reference and algorithm changes. To minimize the switching time in the position estimation and to stabilize the measurement, a robust position-sensing system is proposed. In the system, to minimize the switching delay, the door positions are stored and updated in a database. The reliability and accuracy of the robust positioning system based on DGPS and ABS are verified through the real experiments using a mobile robot prepared for this research and demonstrated.
        214.
        2007.03 KCI 등재 서비스 종료(열람 제한)
        Recently, with the development of service robots and with the new concept of ubiquitous world, the position estimation of mobile objects has been raised to an important problem. As pre-liminary research results, some of the localization schemes are introduced, which provide the absolute location of the moving objects subjected to large errors. To implement a precise and convenient localization system, a new absolute position estimation method for a mobile robot in indoor environment is proposed in this paper. Design and implementation of the localization system comes from the usage of active beacon systems (based upon RFID technology). The active beacon system is composed of an RFID receiver and an ultra-sonic transmitter: 1. The RFID receiver gets the synchronization signal from the mobile robot and 2. The ultra-sonic transmitter sends out the traveling signal to be used for measuring the distance. Position of a mobile robot in a three dimensional space can be calculated basically from the distance information from three beacons and the absolute position information of the beacons themselves. Since it is not easy to install the beacons at a specific position precisely, there exists a large localization error and the installation time takes long. To overcome these problems, and provide a precise and convenient localization system, a new auto calibration algorithm is developed in this paper. Also the extended Kalman filter has been adopted for improving the localization accuracy during the mobile robot navigation. The localization accuracy improvement through the proposed auto calibration algorithm and the extended Kalman filter has been demonstrated by the real experiments.
        215.
        2007.03 KCI 등재 서비스 종료(열람 제한)
        This paper presents a PID automatic gain-tuning algorithm for the electronic throttle valve which is driven by wire. Since the system characteristics of position control for electronic throttle valve are so complicated that both the real time robustness and the manufacturing cost must be considered for mass production. To resolve this paradox, a kind of algorithm called RLS (Recursive Least Square) is adopted for the control of the ETB (Electronic Throttle Body). Using this algorithm, the PID gains can be adjusted automatically with the estimated system parameters. Furthermore, a pre-filter is supplemented for the sake of the robustness against the friction and loads. From the industrial requests for the system, the design specifications are decided as follows: the settling time should be less than 1 sec and the overshoot should be kept below 3%. The results of the experiments based on this approach show that the high robustness can be achieved while the system stability is satisfied steadily. A parameter estimation scheme and a gain-tuning algorithm have been properly combined and utilized in this research and the effectiveness is verified through the real experiments.
        216.
        2006.09 KCI 등재 서비스 종료(열람 제한)
        Though the final goal of mobile robot navigation is to be autonomous, operators intelligent and skillful decisions are necessary when there are many scattered obstacles. There are several limitations even in the camera-based tele-operation of a mobile robot, which is very popular for the mobile robot navigation. For examples, shadowed and curved areas acnnot be viewed using a narrow view-angle camera, especially in bad weather such as on snowy or rainy days. Therefore, it is necessary to have other sensory information for reliable tele-operations. In this paper, sixteen ultrasonic sensors are attached around a mobile robot in a ring pattern to measure the distances to obstacles. Acollision vector is introduced in this paper as a new tool for obstacle avoidance, which is defined as a normal vector from an obstacle to the mobile robot. Based on this collision vector, a virtual reflection force is generated to avoid the obstacles and then the reflection force is transferred to an operator who is holding a joystick to control the mobile robot. Relying on the reflection force, the operator can control the mobile robot more smoothly and safely. For this bi-directional tele-operation, a master joystick system using a hall sensor was designed to resolve the existence of nonlinear sections, which are usual for a general joystick with two motors and potentiometers. Finally, the efficiency of a force reflection joystick is verified through the comparison of two vision-based tele-operation experiments, with and without force reflection.
        217.
        2005.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        김치에 큰느타리버섯을 첨가하여 숙성시키면서 품질특성의 변화를 측정하였다. 버섯 첨가량에 따른 김치의 pH를 측정 한 결과 대조구보다 버섯첨가구의 pH가 전반적으로 약간 낮게 나타났으며, 적정산도는 pH와 반대로 버섯의 첨가량이 높을수록 적정산도가 높았다. 큰느타리버섯 첨가에 따른 김치의 총균수 및 유산균수는 숙성 18일경에 모두 최대치를 보였으며, 이후에는 조금 감소하였다. 특히 버섯 처리구는 총균수 및 유산균수 모두에서 미생물 억제현상이 관찰
        218.
        2005.03 KCI 등재 서비스 종료(열람 제한)
        The objectives of this study are an establishment of developing strategies of environment-friendly agriculture(EFA) around the Daecheong and Chungju Dam. To establish strategic target, a series of farm household survey were conducted for farmers residing around the Daecheong and Chungju Dam. The sample size of the survey is 233 respectively. As a result, the farmers recognized that EFA is fit for around Daecheong and Chungju Dam as well as the prospects is very bright. In conclusion, the main streams to develop EFA are come up with vision and purpose around dam area, systematic connection of environment-friendly agricultural capability around dam area, construction of organic resource circulation system, and connecting propulsion with green tourism including quantitative and qualitative upgrade of environment-friendly agricultural products.
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