• 제어로봇시스템학회논문지
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• 제18권6호
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• pp.571-578
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• 2012

In the paper, we proposed a ring type structured light image based embedded ranging sensor for a mobile robot. Since the proposed ranging sensor obtains omnidirectional object distance, it is useful for autonomous navigation of a mobile robot. By matching the local omnidirectional distance map with a given global object map, it is possible to get position and heading angle of mobile robot in the global coordinates. Experiments for matching and navigation were carried out to verify the performance of the proposed ranging sensor.

• 한국생산제조학회지
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• 제7권4호
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• pp.28-34
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• 1998

This paper presents a new method for local obstacle avoidance of indoor mobile robots. The method combines a directional approach called the lane method and a velocity space approach. The lane method divides working area into lanes and then chooses the best lane to follow for efficient and collision-free movement. Then, the heading direction to enter and follow the best lane is decided, and translational and rotational velocity considering physical limitations of a mobile robot are determined. Since this method combines both the directional and velocity space method, it shows collision-free motion as well as smooth motion taking the dynamic of the robot into account.

• 한국군사과학기술학회지
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• 제12권5호
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• pp.549-556
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• 2009

One of the basic technology for implementing the autonomy of UGV(Unmanned Ground Vehicle) is a path planning algorithm using obstacle and raw terrain information which are gathered from perception sensors such as stereo camera and laser scanner. In this paper, we propose a generation method of DVGM(Directional Velocity Grid Map) which have traverse speed of UGV for the five heading directions except the rear one. The fuzzy system is designed to generate a resonable traveling speed for DVGM from current patch to the next one by using terrain slope, roughness and obstacle information extracted from raw world model data. A simulation is conducted with world model data sampled from real terrain so as to verify the performance of proposed fuzzy inference system.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1996년도 Proceedings International Workshop on New Video Media Technology
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• pp.13-17
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• 1996

This paper presents animation techniques and issues involved in virtual environments where the participants interact with each other through a network. The state of the participant should be recognized at each local site, and broadcast to the other sites. Because information exchange is minimal, animation techniques are applied to convert the incoming low DOF parameters into high DOF joint angles that completely determine the configuration of the agents at each frame. As a case study, a software system VRLOCO is introduced, which has been developed by the author over the last five years. From a simple stream of body center positions, VRLOCO generates realistic curved path human locomotion in real-time. Based on the heading direction and speed, the locomotion automatically switches among five different primitives: walking, running, lateral stepping, backward stepping, and turnaround. The techniques presented here proved robust and faithful: the algorithm is not sensitive to the noise in the data, and the resulting animation conforms well with the original data.

• Ocean Systems Engineering
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• 제9권1호
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• pp.43-77
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• 2019

A local-analytic-based Navier-Stokes solver has been employed in conjunction with a compound ocean structure motion analysis program for time-domain simulation of passing ship effects induced by multiple post-Panamax class ships in the exact condition of a real waterway. The exact seabed bathymetry was reproduced to the utmost precision attainable using the NOAA geophysical database for Virginia Beach, NOAA nautical charts for Hampton Roads and Norfolk harbor, and echo sounding data for the navigation channel and waterfront facilities. A parametric study consists of 112 simulation cases with various combinations of ship lanes, ship speeds, ship heading (inbound or outbound), channel depths, drift angles, and passing ship coupling (in head-on or overtaking encounters) were carried out for two waterfront facilities at NAVSTA Norfolk and Craney Island Fuel Terminal. The present paper provides detailed parametric study results at both locations to investigate the site-specific passing ship effects on the motion responses of ships moored at nearby piers.

• 한국작물학회지
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• 제36권6호
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• pp.496-500
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• 1991

총체용 보리, 밀, 신기호밀의 조사료 생산성 및 사료적 가치를 구명하고자 올보리, 그루밀, 신기호밀을 공시하여 총체수량, 기관별 구성비, 사료적 가치 및 예취적기를 조사한 바를 요약하면 다음과 같다. 1. 총체수량은 호밀>밀>보리의 순으로 많았으며 총체수량이 가장 많은 시기는 보리, 밀은 출수후 14일, 신기호밀은 21일이었다. 2. 기관별 구성비는 세 품종 공히 출수후 일수가 경과할수록 이삭의 비율이 늘고 줄기와 잎은 감소하였다. 보리의 이삭 비율은 황숙기에 56 1%로 밀과 신기호밀에 비하여 월등히 높았다. 3. 사일레지 제조 적정 수분에 도달하는 시기는 보리가 출수후 24-31일, 밀은 출수후 24-35일, 신기호밀은 출수후 25-34일 이었다. 4. 보리의 황숙기 때 조단백, 조지방의 각 10.7%, 4.7%로 밀, 신기호밀에 비하여 높았으며 반면에 보리의 조섬유는 낮았다. 5. 총체수량, 수분함량, 사료가치 및 수도이앙 등을 고려할 때 총체용 맥류의 수확적기는 출수후 23-24일 이었다. 6. 중북부지역에서 답이작 총체용으로는 보리가 가장 적합한 맥종으로 사료되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.140-153
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• 2005

During the tunnel construction the major failure mode can be categorized as: tunnel failure just after the tunnel excavation without support, failure after application of shotcrete and finally failure after setting the concrete lining. The failure mode just after the tunnel excavation without support, can be further classified as : bench failure, crown failure, face failure, full face failure, failure due to weak strata and failure due to overburden. Moreover the failure after application of shotcrete is classified as heading face failure, settlement of shotcrete support, local failure of shotcrete lining and invert shotcrete. To find out the major causes of tunnel collapse, the investigation was done in case of the second phase of Seoul subway construction. The investigation results depicted that the major causes of tunnel collapse were due to the weak layer of rock/fault and sudden influx of ground water from the tunnel crown. While the investigation results of the mountain road tunnels construction have shown that the major causes of tunnel failure were inadequate analysis of tunnel face mapping results, intersection of faults and limestone cavities. In this paper some recent measurement in order to mitigate such tunnel collapse are presented

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.310-310
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• 2017

'Gawaji 1', an early maturing and low amylose content rice variety adaptable to double cropping system with barley as later winter crop., was developed by the crop breeding team of Crop Research Division, GARES, Hwaseong, Korea in 2016. 'Gawaji 1' was derived from a cross between 'Baegjinju' and 'Sangmibyeo' in 2004. This variety had heading date of August 4 in Gyeonggi Province. It had a semi-elect plant type and resistance to lodging with strong culm. Its culm length was 67 cm. This variety had 15 tillers per hill and 104 spikelets per panicle. It was medium grain variety showing 1,000 grain weight of brown rice of 19.3g. Its protein contents of milled rice was 8.2% which was lower than 'Baegjinju'. Its milling ratio was 75.5% which was higher than 'Baegjinju'. The yield of milled rice was 5.0 MT/ha under the ordinary culture of the local adaptability test in 3 areas of Gyeonggi Province for three years. 'Gawaji1' is highly adaptable to Gyeonggi Province, especially to northern region of Han River.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.339-346
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• 2006

Increased usage of autonomous underwater vehicle (AUV) has led to the development of alternative navigational methods that do not employ the acoustic beacons and dead reckoning sensors. This paper describes a simultaneous localization and mapping (SLAM) scheme that uses range sonars mounted on a small AUV. The SLAM is one of such alternative navigation methods for measuring the environment that the vehicle is passing through and providing relative position of AUV by processing the data from sonar measurements. A technique for SLAM algorithm which uses several ranging sonars is presented. This technique utilizes an unscented Kalman filter to estimate the locations of the AUV and objects. In order for the algorithm to work efficiently, the nearest neighbor standard filter is introduced as the algorithm of data association in the SLAM for associating the stored targets the sonar returns at each time step. The proposed SLAM algorithm is tested by simulations under various conditions. The results of the simulation show that the proposed SLAM algorithm is capable of estimating the position of the AUV and the object and demonstrates that the algorithm will perform well in various environments.

• 천문학회보
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• 제36권2호
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• pp.80.2-80.2
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• 2011

The sudden decrease of galactic cosmic ray (GCR) intensity observed by ground neutron monitor (NM) is called a Forbush decrease (FD) event. The intensity time profile of FD event looks like the geomagnetic storm visualized by geomagnetic storm index Dst. Oh et al. [2008] and Oh and Yi [2009] classified the FD events into two kinds by criteria of the overlapping simultaneity of main phase in universal time (UT). The FD event is defined simultaneous if the main phase parts observed by the stations distributed evenly around the Earth are overlapped in UT and non-simultaneous if ones are overlapped in each station's local time (LT). They suggested the occurrence mechanisms of two kind FD events related to the interplanetary magnetic structures such as the interplanetary shock (IP shock) and magnetic cloud. According to their model, the simultaneity of FD depends on the strength and propagation direction of interactive magnetic structures overtaking the Earth. Now the STEREO mission can visualize the emergence and propagation direction of the coronal mass ejection (CME) in 3-dimension in the heliosphere. Thus, it is possible to test the suggested mechanisms causing two different types of FD events. One simultaneous FD observed on February 17, 2011 may be caused by a CME heading directly toward the Earth observed on February 15, 2011 by the STEREO mission. The simultaneity of FD event is proved to be a useful analysis tool in figuring out the geo-effectiveness of solar events such as interplanetary CMEs and IP shocks.