• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.474-479
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• 1993

A study about two-dimensional pursuit-evasion dynamic games is presented and discussed. A pursuer tries to intercept an evader by a strategy based on proportional navigation guidance, while the evader tries to maximize a miss distance by the optimal control. The study is applied to a ball game and an air-combat game. The results show the same features exist in both games, therefore the study will be able to apply for general two dimensional dynamic games. In the ball game, the study is extended to cases where a goal exists, while in the air-combat game, some three-dimensional problems are solved and the results are also shown.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.832-836
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• 1988

"Motion Stereo" is quite useful for visual guidance of the robot, but most range finding algorithms of motion stereo have suffered from poor accuracy due to the quantization noise and measurement error. In this paper, 3-D position estimation and refinement scheme is proposed, and its performance is discussed. The main concept of the approach is to consider the entire frame sequence at the same time rather than to consider the sequence as a pair of images. The experiments using real images have been performed under following conditions : hand-held camera, static object. The result demonstrate that the proposed nonlinear least-square estimation scheme provides reliable and fairly accurate 3-D position information for vision-based position control of robot. of robot.

• Journal of Korea Entertainment Industry Association
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• v.15 no.7
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• pp.45-57
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• 2021

The purpose of this study is to identify what factors have impacts on the amount of YouTube viewing. In doing so, usage type, children's levels of self-control on viewing, parent's perception of media contents, and parental mediation style were investigated by age. The result of the study showed no significant differences of the amount of use by the different age groups. There were, however, significant differences in terms of subscription status(non subscription based vs. subscription-based viewing), level of self-control, perception of content, and parent's mediations (technology, supervision, and guidance). Given the amount of YouTube use, the subscription status and parent's supervision were significantly influential factors for the age group of 3-4 years old. For the age group of 5-6, subscription status, levels of self-control, and mediation of parent's supervision and guidance were influential factors. For the age of 7-9, subscription status, the level of self control, and premium service were significantly influential. Finding similarities and differences in meaningful variables by age group suggests that different strategies should be used to reduce the amount of children's YouTube use. In addition, it raises the need for a more detailed classification of children's YouTube usage methods, which have not been addressed so far, and the need for research on the influence of these methods.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.519-521
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• 1987

Among the gyroscopes used for SDINS, the dynamically turned gyroscope (DTG) covers a wide dynamic range while it is simple and small. In addition, it is a two-degree-of freedom gyro; it can detect two-axis input simultaneously. DTG, since its development in 1970's, is widely accepted for strapdown inertial systems. In the first year, we have concentrated on developing a two degree-of-freedom DIG. An interdisciplinary research team has been formed to accomplish the first year objective. Five departments in the College of Engineering, Seoul National University are involved. They are; 1) Department of Control and Instrumentation, 2) Department of Mechanical Design and Production, 3) Department of Electrical Engineering, 4) Department of Electronic Engineering, and 5) Department of Metallurgical Engineering. In addition, the Department of Precision Mechanical Engineering of Pusan National University is subcontracted to develop a test procedure for gyroscope and SDINS. Gyroscope is a key sensor for SDINS. Furthermore gyroscope itself is used as a. independent sensor for vehicle guidance and control and fire control system. Gyroscope and SDINS are an important for defense, aeronautical, and space industries that Korea is and will be actively involved. Upon the success of the project, they are expected to be manufactured in Korea under a cooperative effort between university and industry.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.633-643
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• 2005

An unmanned aerial vehicle (UAV) is an aircraft controlled by .emote commands from ground station and/o. pre-programmed onboard autopilot system. A navigation system in the UAV provides a navigation data for a flight control computer(FCC). The FCC requires accurate and reliable position, velocity and attitude information for guidance and control. This paper proposes an ADGPS/INS integrated navigation system for a UAV. The proposed navigation system comprises an attitude determination GPS (ADGPS) receive., a navigation computer unit, and a low-cost commercial MEMS inertial measurement unit(IMU). The navigation algorithm contains a fault detection and isolation (FDI) function fur integrity. In order to evaluate the performance of the proposed navigation system, two flight tests were preformed using a small aircraft. The first flight test was carried out to confirm fundamental operation of the proposed navigation system and to check the effectiveness of the FDI algorithm. In the second flight test, the navigation performance and the benefit of the GPS attitude information were checked in a high dynamic environment. The flight test results show that the proposed ADGPS/INS integrated navigation system gives a reliable performance even when anomalous GPS data is provided and better navigation performance than a conventional GPS/INS integration unit.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.1
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• pp.120-131
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• 2016

The full results of troubleshooting process related to the flight control system of a tilt-rotor type UAV in the flight tests are described. Flight tests were conducted in helicopter, conversion, and airplane modes. The vehicle was flown using automatic functions, which include speed-hold, altitude-hold, heading-hold, guidance modes, as well as automatic take-off and landing. Many unexpected problems occurred during the envelope expansion tests which were mostly under those automatic functions. The anomalies in helicopter mode include vortex ring state (VRS), long delay in the automatic take-off, and the initial overshoot in the automatic landing. In contrast, the anomalies in conversion mode are untrimmed AOS oscillation and the calibration errors of the air data sensors. The problems of low damping in rotor speed and roll rate responses are found in airplane mode. Once all of the known problems had been solved, the vehicle in airplane mode gradually reached the maximum design speed of 440km/h at the operation altitude of 3km. This paper also presents a comprehensive detailing of the control systems of the tilt-rotor unmanned air vehicle (UAV).

• Journal of Power System Engineering
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• v.7 no.4
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• pp.67-73
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• 2003

The entry guidance design involves trajectory optimization and generation of a drag acceleration profile as the satisfaction of trajectory conditions during the entry flight. The reference trajectory is parameterized and optimized as piecewise linear functions of the velocity. A regularization technique is employed to achieve desired properties of the optimal drag profile. The regularized problem has smoothness properties and the minimization of performance index then prevents the drag acceleration from varying too fast, thus eliminating discontinuities. This paper shows the trajectory control using the simple control law as well as the information of reference drag acceleration.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9875-9877
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• 2014

Objective: To access the safety of chemotherapy for elderly cancer patients complicated with hypertension. Methods: Elderly cancer patients who were complicated with hypertension and treated by chemotherapy were recruited. All patients were treated by chemotherapy after an intervention on hypertension by psychotherapy, exercise guidance, salt regulation and nutrition support, therapy on hypertension, as well as prevention on hypertension associated complications. Results: In 68 eligible patients, two suspended chemotherapy because of adverse reactions and 4 because of disease progression. The remaining 62 patients completed chemotherapy smoothly based on good hypertension control. Conclusion: With effective control of blood pressure, chemotherapy for elderly cancer patients complicated with hypertension is generally safe.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.1
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• pp.72-77
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• 1999

The mono-hydrazine thrusters which have been selected for satellite auxilliarly propulsion system since 1960s were koreanized for KOMPSAT attitude control. In this paper, design and manufacturing, test of the mono-hydrazine thruster were briefly reviewed with KOMPSAT attitude control thrusters and the key technology to be developed in the future for various small thrusters of launch vehicle, satellite and guidance missile were proposed.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.1
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• pp.23-30
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• 2009

This paper addresses how to make a formation of multiple unmanned aerial vehicles (UAVs) using only the relative range information. Since the relative range can easily be measured by an on-board range sensor like the laser range finder, the proposed method does not require any expensive and heavy wireless communication system to share the navigation information of each vehicle. Based on the two-dimensional (2-D) nonlinear equations of motion, we propose a nonlinear formation controller using the typical input-output feedback linearization method. The performance of the proposed formation controller is verified by various numerical simulations.