• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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• pp.159-166
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• 2019

Due to the various engagement situations, it is very difficult to generate the optimal trajectory with several constraints. This paper investigates the sequential convex programming for the impact angle control with the additional constraint of altitude limit. Recently, the SOCP(Second-Order Cone Programming), which is one area of the convex optimization, is widely used to solve variable optimal problems because it is robust to initial values, and resolves problems quickly and reliably. The trajectory optimization problem is reconstructed as convex optimization problem using appropriate linearization and discretization. Finally, simulation results are compared with analytic result and nonlinear optimization result for verification.

• Korean Journal of Remote Sensing
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• v.33 no.5_3
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• pp.879-888
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• 2017

This study is a preliminary research conducted in Buhansan mountain National Park to develop a management system to predict and control oak wilt disease by indicating spatial factors which affect diffusion of the disease. After analysing altitude factor during the estimation of spatial analysis of damaged area, it is indicated that damaged trees are mainly distributed at altitude of 200-500 m and number decreased drastically over the altitude of 500 m. The result showed that 92% of total damaged trees are on slope between 20~40 degrees and the number decreased drastically on slope steeper than 40 degrees. It is indicated that damaged area is mainly distributed on southern aspect. It is estimated by using CART that slope factor affected the diffusion of disease mostly but aspect factor did not. Surface temperature and altitude showed similar effect.By simulating possible diffusion scenario, it is estimated that the disease could spread to DO-BONG Mt., northeast of Bukhansan mountain.

• Journal of the Korea Society for Simulation
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• v.33 no.2
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• pp.37-44
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• 2024

The Korean Helicopter Development Program has successfully introduced the Surion helicopter, a versatile multi-domain operational aircraft that replaces the aging UH-1 and 500MD helicopters. Specifically designed for maneuverability, the Surion plays a crucial role in low-altitude tactical maneuvers for personnel transportation and specific missions, emphasizing the helicopter's survivability. Despite the significance of its low-altitude tactical maneuver capability, there is a notable gap in research focusing on multi-mission tactical maneuvers that consider the risk factors associated with deploying the Surion in the presence of enemy air defenses. This study addresses this gap by exploring a method to enhance the Surion's low-altitude maneuvering paths, incorporating information about enemy air defenses. Leveraging the Proximal Policy Optimization (PPO) algorithm, a reinforcement learning-based approach, the research aims to optimize the helicopter's path planning. Visualized experiments were conducted using a Surion model implemented in the Unity environment and ML-Agents library. The proposed method resulted in a rapid and stable policy convergence for generating optimal maneuvering paths for the Surion. The experiments, based on two key criteria, "operation time" and "minimum damage," revealed distinct optimal paths. This divergence suggests the potential for effective tactical maneuvers in low-altitude situations, considering the risk factors associated with enemy air defenses. Importantly, the Surion's capability for remote control in all directions enhances its adaptability in complex operational environments.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.2
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• pp.164-170
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• 2013

Quadrotor UAV (Unmanned Aerial Vehicle) is a flying robotic platform which has drawn lots of attention in the recent years. The attraction comes from the fact that it is able to perform agile VTOL (Vertical Take-Off Landing) and hovering functions. In addition, the efficient modular structure composed of four electric rotors makes its design easier compared to other single-rotor type helicopters. In many cases, a quadrotor often utilizes vision systems in order to obtain altitude control and navigation solution in hostile environments where GPS receivers are not working or deniable. For carrying out their successful missions, it is essential for flight control systems to have fast and stable control responses of heading angle outputs. This paper presents a Fuzzy Logic based lateral PI controller to stabilize and control the quadrotor vehicle equipped with vision systems. The advantage of using the fuzzy based PI controller lies in the fact that it could acquire a desired output response of a heading angle even in presence of disturbances and uncertainties. The performance comparison of the newly proposed Fuzzy-PI controller and the conventional PI controller was carried out with various simulation results.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.199-201
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• 2008

In this paper proposed the solar tracking system to use direct fuzzy control order to increase an output of the PV (Photovoltaic) array. The solar tracking system operated two DC motors driving by signal of photo sensor. The control of dual axes is not an easy task due to nonlinear dynamics and unavailability of the parameters. Recently, artificial intelligent control of the fuzzy control, neural-network and genetic algorithm etc. have been studied. The fuzzy control made a nonlinear dynamics to well perform and had a robust and highly efficient characteristic about a parameter variable as well as a nonlinear characteristic. Hence the fuzzy control was used to perform the tracking system after comparing with error values of setting-up, nonlinear altitude and azimuth. In this paper designed a DFC(Direct Fuzzy Control)controller for improving output of PV array and evaluated comparison with efficient of conventional PI controller. The data which were obtained by experiment were able to show a validity of the proposed controller.

• Journal of Convergence for Information Technology
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• v.10 no.10
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• pp.123-127
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• 2020

In order to obtain the overall fire line information of medium and large forest fires at night, the ground control system was developed to determine whether forest fires occurred through real-time video clips and to calculate the location of the forest fires determined using the location of drones, angle information of video cameras, and altitude information on the map to reduce the time required for regular video matches obtained after the completion of the mission. To verify the reliability of the developed function, the error distance of the aiming position information of the flight altitude star and the image camera was measured, and the location information within the reliable range was displayed on the map. As the function developed in this paper allows real-time identification of multiple locations of forest fires, it is expected that overall fire line information for the establishment of forest fire extinguishing measures will be obtained more quickly.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.9
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• pp.888-897
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• 2015

A flight capability to take a terrain following flight near the ground is required to reduce the probability that a fighter aircraft can be detected by foe's radar fence in the battlefield. The success rate for mission flight has increased by adopting TFS (Terrain Following System) to enable the modern advanced fighter to fly safely near the ground at the low altitude. This system has applied to the state-of-the-art fighter and bomber, such as B-1, F-111, F-16 E/F and F-15, since the research begins from 1960's. In this paper, the terrain following system and GCAS (Ground Collision Avoidance System) was developed, based on a digital database with UTAS's TERPRROM (TERrain PROfile Matching) equipment. This system calculates the relative location of the aircraft in the terrain database by using the aircraft status information provided by the radar altimeter and the INS (Inertial Navigation System), based on the digital terrain database loaded previously in the DTC (Data Transfer Cartridge), and figures out terrain features around. And, the system is a manual terrain following system which makes a steering command cue refer to flight path marker, on the HUD (Head Up Display), for vertical acceleration essential for terrain following flight and enables a pilot to follow it. The cue is based on the recognized terrain features and TCH (Target Clearance Height) set by a pilot in advance. The developed terrain following system was verified in the real-time pilot evaluation in FA-50 HQS (Handling Quality Simulator) environment.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.1
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• pp.24-30
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• 2016

The accuracy of small and low-cost CCD cameras is insufficient to provide data for precisely tracking unmanned aerial vehicles (UAVs). This study shows how a quad rotor UAV can hover on a human targeted tracking object by using data from a CCD camera rather than imprecise GPS data. To realize this, quadcopter UAVs need to recognize their position and posture in known environments as well as unknown environments. Moreover, it is necessary for their localization to occur naturally. It is desirable for UAVs to estimate their position by solving uncertainty for quadcopter UAV hovering, as this is one of the most important problems. In this paper, we describe a method for determining the altitude of a quadcopter UAV using image information of a moving object like a walking human. This method combines the observed position from GPS sensors and the estimated position from images captured by a fixed camera to localize a UAV. Using the a priori known path of a quadcopter UAV in the world coordinates and a perspective camera model, we derive the geometric constraint equations that represent the relation between image frame coordinates for a moving object and the estimated quadcopter UAV's altitude. Since the equations are based on the geometric constraint equation, measurement error may exist all the time. The proposed method utilizes the error between the observed and estimated image coordinates to localize the quadcopter UAV. The Kalman filter scheme is applied for this method. Its performance is verified by a computer simulation and experiments.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.333-336
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• 2003

For long time, the takeoff and landing control of airship was worked by human handling. With the development of the autonomous control system, the exact controls during the takeoff and landing were required and lots of methods and algorithms were suggested. This paper presents the result of airship take-off and landing by buoyancy control using air ballonet volume change and performance control of pitch angle for stable flight within the desired altitude. For the complexity of airship's dynamics, firstly, simple PID controller was applied. Due to the various atmospheric conditions, this controller didn’t give satisfactory results. Therefore, new control method was designed to reduce rapidly the error between designed trajectory and actual trajectory by learning algorithm using an artificial neural network. Generally, ANN has various weaknesses such as large training time, selection of neuron and hidden layer numbers required to deal with complex problem. To overcome these drawbacks, in this paper, the RBFN (radial basis function network) controller developed.

• Journal of the Korean Home Economics Association
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• v.38 no.6
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• pp.101-116
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• 2000

This study integrated mother's control behavior of child's misbehavior within social domain analysis and the framework of attributional models of social cognition. The purpose of this study was to identify, compare and contrast maternal attributions and control responses according to child's age and domains of social behavior, and to investigate that mother's social cognition factors(authoritarian attitude and self competence perception) influence material inference and responses for their child's acts. Then this study was to find out whether mother's attribution would mediate their socialization techniques. For empirical research, 654 mothers with 5.6 year old and 8.9 year old children as subjects answered the structured questionnaire. The data were analyzed by frequencies, t-test, oneway ANOVA, and multiple regression. The major findings were as follows: First, according to child's two domains of misbehavior, there were differences in mothers'attribution and control behavior. Also mothers regarded older child's behavior as more dispositional cause and as more deserving of punishment than younger child's. Second, mother's authoritarian altitude of parenting, self-competence perception, and educational level were significantly related to mother's judgment. Third, the more authoritarian attitude mothers had, the more dispositional factor of children they attributed. And the lower self-competence mothers perceived. the more internal factor of child they attributed. Finally, maternal attributions and control responses are interrelated. When they attributed their children's misdeeds to internal dispositions, they respond with more stronger control behavior. The results suggested maternal social cognition mediate socialization behavior.