• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.288-289
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• 2007

본 논문에서는 통계적 파라미터 불확실성을 포함한 시변 선형 불확정 시스템에 대한 강인 칼만필터링 문제를 고려한다. 최소자승 관점에서 정의된 공칭 칼만필터링 문제의 목적함수를 파라미터 불확실성의 통계적 특성을 이용하여 가용한 측정행렬의 함수로 표현하고, 이로부터 근사화된 선형공간 위로의 사교사영으로 해를 도출할 수 있음을 보인다. 최종적으로 벡터 최소자승 추정기법을 동일하게 적용하여, 순환강인 칼만필터식을 유도하고, 유도된 강인 칼만필터 식이 최근 제안된 강인 최소자승 추정식에 공정잡음 및 측정잡음 분산을 반영한 보완된 형태임을 확인한다.

• Journal of Advanced Navigation Technology
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• v.19 no.1
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• pp.33-40
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• 2015

Advanced surface movement guidance and control system (A-SMGCS) is a system providing routing, guidance and surveillance for the control of aircraft and vehicles in order to maintain the predetermined surface movement rate under all weather conditions while maintaining the required level of safety. In the present study, system engineering was introduced to develop the compliance procedure for the A-SMGCS. At first, requirements for the level IV A-SMGCS were defined and analyzed from the concept of operations (CONOPS). Then, system architecture and specifications were constructed through the functional analysis and allocation. After that, work breakdown structure (WBS) and related integrated master schedule (IMS) were established. Lastly, compliance checklist (CCL) and test and evaluation master plan (TEMP) were developed to verify and validate the system.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.5
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• pp.696-705
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• 2007

Statement of problem: In the Protar articulator, the models are almost parallel with the Camper's plane. The ultrasonic-based ARCUSdigma system is basis for the determination of dynamic function parameters with so-called "articulator related registration". Purpose: The purpose of this study was to compare the sagittal condylar guidance angles found by use of the wax protrusive records in a semi-adjustable articulator(KaVo Protar 7) with those found by use of the Axiograph (ARCUSdigma). 83 volunteers with intact dentition participated in this study after obtainment of informed consent. Material and method: The sagittal condylar guidance angles were measured and estimated statistically by semi-articulator and Axiograph. All the readings were in degrees. No control was used in this project. To test whether there was a significant difference between the 2 independent samples, paired t-test and Kruskal-Wallis test were carried out(p=.05). Results: 1. The mean results for the wax protrusive records were as follow: right side (32.65 degrees, SD 16.48); left side (33.27 degrees, SD 17.49). 2. The mean results for the Axiograph were as follow: right side (32.26 degrees, SD 7.00); left side (33.07 degrees, SD 7.58). 3. There was no statistical difference on the wax protrusive records and Axiograph(p>0.05). Conclusion: Both methods of wax protrusive records and Axiograph are clinically acceptable for measuring the sagittal condylar guidance angles in semi-adjustable articulators.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.10
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• pp.842-850
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• 2014

This paper presents a trajectory tracking controller for rotorcraft UAVs to improve the tracking performances in the presence of various uncertainties. The proposed tracking method consists of a velocity guidance law based on the relative distance and L1 adaptive augmentation loop for tracking the velocity commands. In the proposed structure, the desired velocity generated by the guidance law is the reference value of the adaptive controller for accurate path tracking. In the guidance law, the desired acceleration is generated based on the relative distance and its derivatives, and then the velocity command of the inner control loop is calculated by integrating the accelerations. $L_1$ augmentation loop supplements the linear controller to guarantee the flight performances such as a tracking accuracy in the presence of the uncertainties. The proposed controller was validated in actual flight tests to successfully demonstrate its capability using a quadrotor UAV.

• 한국항공운항학회:학술대회논문집
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• 2004.11a
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• pp.295-301
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• 2004

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1736-1737
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• 2011

This paper deals with the problem of precise impact angle control of an actual homing missile guided by biased proportional navigation (BPN). To do this, the BPN guidance loop including dynamic lag is modeled as the confluent hyper-geometric differential equation and its analytic solution is derived. Based on the solution, a systematic way to determine the bias constant is newly devised. Different from the existing BPN solution obtained by ignoring the dynamic lag, the proposed one can exactly describe the behavior missile before target interception. hence it is drastically improved the angle constrained terminal guidance performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.8
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• pp.558-565
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• 2019

A lot of studies on the survivability of missiles have been widely studied, since the technology of modern warships equipped with state-of-the-art defense systems has been improved. The survivability of missiles can be improved by attacking a target simultaneously using multiple missiles. For this reason, impact time control guidance (ITCG) laws have been widely studied. This paper deals with the effect of time-to-go estimate to ITCG laws. In this paper, two kinds of time-to-go estimate are first introduced in two-dimensional and three-dimensional environment and then ITCG laws are derived using the time-to-go estimate. Numerical simulations are performed to analyze the performance of the designed ITCG laws and the effect of time-to-go estimate is discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.3
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• pp.12-15
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• 1978

The agriculture in Korea has been gradually changed from a labor-intensive type to a labor-saving one which aims to maximize productivity of labor. Herbicides have been utilized in rice farming since 1955. The consumption of herbicides rapidly increased during the last decade. However, the technology of weed control with herbicides has not been developed yet. For the dissemination of efficient weed control methods in farming, both research and extension activities on herbicide utilization should be strengthened. Appropriate research and guidance units on weed control should be established as early as possible, in order to provide the necessary technical information.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.3
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• pp.170-184
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• 2024

With the advancement of autonomous navigation technology in maritime domain, there is an active research on swarming Unmanned Surface Vehicles (USVs) that can fulfill missions with low cost and high efficiency. In this study, we propose a formation control algorithm that maintains a certain shape when multiple unmanned surface vehicles operate in a swarm. In the case of swarming, individual USVs need to be able to accurately follow the target state and avoid collisions with obstacles or other vessels in the swarm. In order to generate guidance commands for swarm formation control, the potential field method has been a major focus of swarm control research, but the method using the potential field only uses the position information of obstacles or other ships, so it cannot effectively respond to moving targets and obstacles. In situations such as the formation change of a swarm of ships, the formation control is performed in a dense environment, so the position and velocity information of the target and nearby obstacles must be considered to effectively change the formation. In order to overcome these limitations, this paper applies a method that considers relative velocity to the potential field-based guidance law to improve target following and collision avoidance performance. Considering the relative velocity of the moving target, the potential field for nearby obstacles is newly defined by utilizing the concept of Velocity Obstacle (VO), and the effectiveness and efficiency of the proposed method is verified through swarm control simulation, and swarm control experiments using a small scaled unmanned surface vehicle platform.

• Journal of Biosystems Engineering
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• v.13 no.2
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• pp.38-45
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• 1988

This study was intended to develop the system automatically controlling travel direction of combine by means of sensing paddy rows. The control system was composed of three detecting levers having different length, micro-switch, microcomputer and electro-hydraulic control system. Sensor and control system developed was tested to estimate optimum design values and its actual performance as installed in combine. The computer simulation and performance test at simulated and actual field were conducted to test for possibility of practical use. The results of the study arc summarized. as follows: 1. The travel traces of combine hiving the conventional sensor with 2 levers and the new sensor detecting the slope of paddy rows were compared through computer simulation. Turning frequency of combine having new sensor was fewer than that of conventional sensor, but the rate of turning for the combine with new sensor was much greater than that of conventional sensor. 2. As sensor was established behind the tip of divider, the sensor itself well followed paddy rows but the tip of divider did not, resulting in divider being deviated from paddy rows. It was analyzed that the sensor should be attached closer to the tip of divider to have a better performance of the control system. 3. The greater the length of sensor lever for given location of sensor attachment and combine forward speed, the higher sensitivity of turning in control system. Moreover, increasing combine speed resulted in a worse performance of control system following paddy rows. Consequently, it was necessary that an optimum length of sensor attachment and for the range of combine operational speed. 4. Field test of combine installed with the sensor and electro-hydraulic system developed in this study showed that it may be operated smoothly and well behaved to paddy rows to 4th gear of combine speed which was 59cm/s. Consequently. it was concluded that the combine with the guidance control system developed in this study may be successfully used for paddy combining.