• Journal of Institute of Control, Robotics and Systems
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• v.8 no.9
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• pp.803-811
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• 2002

Machine vision systems are usually used to identify traffic lanes and then determine the steering angle of an autonomous vehicle in real time. The steering angle is calculated using a geometric model of various parameters including the orientation, position, and hardware specification of a camera in the machine vision system. To find the accurate values of the parameters, camera calibration is required. This paper presents a new camera-calibration algorithm using known traffic lane features, line thickness and lane width. The camera parameters considered are divided into two groups: Group I (the camera orientation, the uncertainty image scale factor, and the focal length) and Group II(the camera position). First, six control points are extracted from an image of two traffic lines and then eight nonlinear equations are generated based on the points. The least square method is used to find the estimates for the Group I parameters. Finally, values of the Group II parameters are determined using point correspondences between the image and its corresponding real world. Experimental results prove the feasibility of the proposed algorithm.

• Current Industrial and Technological Trends in Aerospace
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• v.8 no.2
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• pp.76-85
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• 2010

This paper discusses recent development trends of fiber optic gyroscope (FOG) in space application. Fiber optic gyroscope utilizes Sagnac effect to measure the angular rate of a rotating object in space. Having a rather short development history compared to ring laser gyroscope (RLG), the fiber optic gyroscope, owing to the emerging technologies in fiber optic society and the digital signal processing technique, reveals itself as a noteworthy replacement of the ring laser gyroscope in the space mission. This paper summarizes the current trends of fiber optic gyroscope based on the actual products commercialized in the market over the last decades, while presenting the future development trends of the fiber optic gyroscope in the space exploration.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.332-338
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• 2010

This paper presents a study of path-planning method for AGV(automated guided vehicle) based on path-tracking. It is important to find an optimized path among the AGV techniques. This is due to the fact that the AGV is conditioned to follow the predetermined path. Consequently, the path-planning method is implemented directly affects the whole AGV operation in terms of its performance efficiency. In many existing methods are used optimization algorithms to find optimized path. However, such methods are often prone with problems in handling the issue of inefficiency that exists in system's operation due to inherent undue time delay created by heavy load of complex computation. To solve such problems, we offer path-planning method using modified binary tree. For the purpose of our experiment, we initially designed a AGV that is equiped with laser navigation, two encoders, a gyro sensor that is meant to be operated within actual environment with given set of constrictions and layout for the AGV testing. The result of our study reflects the fact that within such environments, the proposed method showed improvement in its efficiency in finding optimized path.

• Proceedings of KOSOMES biannual meeting
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• 2005.11a
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• pp.27-33
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• 2005

The IMO manoeuvrability standard was established for preventing sea accidents such as collisions and strandings due to the lack of manoeuvrability. The standard of ship manoeuvrability enforced by resolution MSC.137(76) has been applied to vessels of 100m or more in length and all chemical tankers and gas carriers regardless of the length, which were constructed on or after 1 July 1994. The IMO manoeuvrability standard is able to be divided into three kinds as followings; (1) Turning capability standard: Estimated values in design stage are to be certified by turning cir치e test q the actual vessel (2) Course keeping quality standard: Estimated values in design stage are to be certified by 10 deg. and 20 deg. zig-zag tests of the actual vessel. (3) Shortest stopping distance standard: Estimated value in design stage is to be certified by the shortest stopping distance tested by the actual vessel. In this paper, the authors verified the criteria of IMO manoeuvrability standard comparing them with the values resulted from sea trial tests of various kinds q actual vessels and examined separately the validity of all criteria of the standard.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.60-66
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• 2006

This paper presents a new algorithm for the K shortest path problem in a directed network. After a shortest path is produced with Dijkstra algorithm, detouring paths through inward arcs to every vertex of the shortest path are generated. A length of a detouring path is the sum of both the length of the inward arc and the difference between the shortest distance from the origin to the head vertex and that to the tail vertex. K-1 shorter paths are selected among the detouring paths and put into the set of K paths. Then detouring paths through inward arcs to every vertex of the second shortest path are generated. If there is a shorter path than the current Kth path in the set, this path is placed in the set and the Kth path is removed from the set, and the paths in the set is rearranged in the ascending order of lengths. This procedure of generating the detouring paths and rearranging the set is repeated for the K-1 st path of the set. This algorithm can be applied to a problem of generating the detouring paths in the navigation system for ITS and also for vehicle routing problems.

• Electronics and Telecommunications Trends
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• v.35 no.5
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• pp.112-122
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• 2020

In 3D computer graphics, a depth map is an image that provides information related to the distance from the viewpoint to the subject's surface. Stereo sensors, depth cameras, and imaging systems using an active illumination system and a time-resolved detector can perform accurate depth measurements with their own light sources. The 3D image information obtained through the depth map is useful in 3D modeling, autonomous vehicle navigation, object recognition and remote gesture detection, resolution-enhanced medical images, aviation and defense technology, and robotics. In addition, the depth map information is important data used for extracting and restoring multi-view images, and extracting phase information required for digital hologram synthesis. This study is oriented toward a recent research trend in deep learning-based 3D data analysis methods and depth map information extraction technology using a convolutional neural network. Further, the study focuses on 3D image processing technology related to digital hologram and multi-view image extraction/reconstruction, which are becoming more popular as the computing power of hardware rapidly increases.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.48-53
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• 2014

Rocket, held using the CCA for the mission, a plurality of recording devices, and navigation equipment. In case of a projectile which is entered the water after fired into the air, after performing stages and fairing separated in flight to enter the underwater. It is caused by the explosion of gunpowder mainly, vibration phenomenon of a large transition is induced structurally very, also on entering the water, have a significant shock structurally separated. If shock is transmitted directly to the CCA through the body, it can be caused malfunction of payloads, resulting in failure of the mission of the projectile. In order to ensure the stability against shock, in this paper, Calculating a target resonacne frequency of the CCA, and verified through modal test and analysis. Maximum acceleration position of CCA is checked by SRS analysis. In addition, effectiveness of shock isolation system through shock analysis.

• Journal of the Korean Society of Safety
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• v.24 no.4
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• pp.104-110
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• 2009

In this driving simulation study, the impairing effects of various types of electronic devices usage(i. e., destination search by using in-vehicle navigation system, TV watching and dialing cellular phone) during driving on front-to-rear-end collision avoidance were investigated. Percentage of collisions, driving speeds when the drivers collided, and initial reaction time for collision avoidance were analyzed and compared as the dependent measures. The results indicated that (1) any types of electronic devices usage during driving induced more serious collision-related impairment than control condition where no additional task was required, and (2) in general, destination search task appeared to impair drivers collision avoidance performance more than the other task requirements in terms of percentage of collisions and initial reaction time for collision avoidance, but TV watching induced most serious collision impact. These results suggested that any types of electronic device usage could distract drivers attention from the primary task of driving, and be resulted in serious outcome in potentially risky situation of front-to-rear-end collision. In particular, mandatory use of eye-hand coordination and receiving feedback seemed to one of essential factor leading the drivers visual attentional distraction.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.442-442
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• 2012

농업용저수지 수질측정 현황은 17,600여 개소 농업용저수지 중 농업용수 수질측정망 조사시설은 저수지 800개소이며, 농업용 호소로서 환경부 조사 시행 호소수질측정망시설 26개소(저수지 16개소, 담수호 10개소)를 포함한 826개소를 대상으로 농업용수 수질을 분석 평가하고 있다. 저수지 자율항법 자동수질측정을 위하여 개발한 운영시스템은 내용적측정 무인탐사선과의 연계운항 제어모듈 개발 및 저수지 수질측정을 위한 최적항로 운항모듈을 개발하였다. 자율항법 무인탐사선의 자동수질 측정을 위한 운항 제어 알고리즘 설계를 위하여 기존의 자율항법 탐사선의 운항 알고리즘과 수질자동 측정장치 제어 알고리즘을 분석하여 연계 제어모듈을 설계하고 프로그래밍 하였다. 운영과정은 선박운영 프로그램에서 수질모니터링 프로그램으로 Operation Start 명령을 전송하면 수질모니터링 프로그램에서 이 명령을 수신한 이후에 윈치제어 및 수질측정, 각 해당 수심에서 시료채수를 수행한 이후에 Opeartion End 신호를 선박운영 프로그램에 전송하면 다음 지점으로 이동할 수 있도록 하였다. 이를 통하여 효율적인 농업용저수지의 무인자동 수질측정 및 채수기술을 개발 제공하도록 하겠다.

• The Journal of Korea Robotics Society
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• v.18 no.1
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• pp.72-81
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• 2023

We introduce tightly-coupled GNSS-LiDAR-Inertial state estimator, which is capable of SLAM (Simultaneously Localization and Mapping) and autonomous driving. Long term drift is one of the main sources of estimation error, and some LiDAR SLAM framework utilize loop closure to overcome this error. However, when loop closing event happens, one's current state could change abruptly and pose some safety issues on drivers. Directly utilizing GNSS (Global Navigation Satellite System) positioning information could help alleviating this problem, but accurate information is not always available and inaccurate vertical positioning issues still exist. We thus propose our method which tightly couples raw GNSS measurements into LiDAR-Inertial SLAM framework which can handle satellite positioning information regardless of its uncertainty. Also, with NLOS (Non-light-of-sight) satellite signal handling, we can estimate our states more smoothly and accurately. With several autonomous driving tests on AGV (Autonomous Ground Vehicle), we verified that our method can be applied to real-world problem.