• 드라이브 ㆍ 컨트롤
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• 제18권2호
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• pp.20-31
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• 2021

An excavator is a construction machine that can perform various tasks such as trenching, piping, excavating, slope cutting, grading, and rock demolishing. In the 2010s, unmanned construction equipment using ICT technology was continuously developed. In this paper, the path design process was studied to implement the output data of the decision stage, and the path design algorithm was developed. For example, the output data of the decision stage were terrain data around the excavator, excavator mechanism information, excavator hydraulic information, the position and posture of the bucket at key points, the speed of the desired bucket path, and the required excavation volume. The result of the path design was the movement of the hydraulic cylinder, boom arm, bucket, and bucket edge. The core functions of the path design algorithm are the function of avoiding impact during the excavation process, the function to calculate the excavation depth that satisfies the required excavation volume, and the function that allows the bucket to pass through the main points of the excavation process while maintaining the speed of the desired path. In particular, in the process of developing the last function, the node tracking method expressed in the path design table was newly developed. The path design algorithm was verified as this path design satisfied the JCMAS H02 requirement.

• 대한기계학회논문집
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• 제15권1호
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• pp.98-106
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• 1991

본 연구에서는 로봇이용의 자동화를 위하여 가장 필수적인 과정인 로봇의 운 동경로 계획에 관하여 연구하고 작업영역 내에 장애물이 있는 경우에 로봇과 장애물과 의 충돌 회피를 위한 정량적인 양으로 두물체간의 최소거리 및 충돌깊이를 효율적으로 계산할 수 있는 방법을 제안하며 이를 이용하여 로봇이 장애물과 충돌하지 않고 주어 진 작업을 수행할 수 있는 로봇의 경로를 자동으로 생성함으로써 로봇을 보다 상위레 벨에서 운용하기 위한 기초를 마련한다.

• Journal of the korean society of oceanography
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• 제37권3호
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• pp.196-200
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• 2002

The time variation in the Kuroshio is studied by use of nine observed distances of the main Kuroshio axis from the Japanese coast. The observed distances over 1975 - 1995 are estimated from the Prompt Report of Oceanographic Conditions published by Hydrographic Department of the Maritime Safety Agency of Japan. It is shown that large sea level difference between Naze and Nishinoomote, which represents the volume transport of the southern inflow south of Kyushu, coincides with larger distance of the Kuroshio in the upstream area from off Kyushu to off eastern Kii Peninsula and smaller distance in the downstream area from off Omae-zaki to off Boso Peninsula. In contrast, large sea level difference between Nishinoomote and Aburatsu, which represents the volume transport of northern inflow south of Kyushu, corresponds to smaller distance in the upstream area and larger distance in the downstream area. Path dynamics of the Kuroshio is discussed with reference to the variation in Volume transport south of Kyushu.

• 한국국방경영분석학회지
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• 제17권2호
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• pp.72-89
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• 1991

In transportation network problems, it is often desirable to select multiple number of the shortect paths. On problems of finding these paths, algorithms have been developed to choose single shortest path, k-shortest paths and k-shortest paths via p-specified nodes in a network. These problems consider the time as the main factor. In wartime, we must consider availability as well as time to determine the shortest transportation path, since we must take into account enemy's threat. Therefore, this paper addresses the problem of finding the shortest transportation path considering both time and availability. To accomplish the objective of this study, values of k-shortest paths are computed using the algorithm for finding the k-shortest paths. Then availabilties of those paths are computed through simulation considering factors such as rates of suffering attack, damage and repair rates of the paths. An optimal path is selected using any one of the four decision rules that combine the value and availability of a path.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1046-1050
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• 2003

In this paper, we describe study on the development or multi-path ultrasonic gas flowmeter using a transit time method. This system includes 5 pairs of ultrasonic transducers. ultrasonic signal processing unit using switch matrix method, computation algorithm of gas flow rate, spool piece type multi-path pipe unit. We have developed enhanced type of main ultrasonic signal processing unit using switch matrix method fer multi-path ultrasonic gas flowmeter. Also, we have developed the new transmitting ＆ receiving method of ultrasonic waves and the new signal processing algorithm for the computation of ultrasonic transit time from received ultrasonic waves. In this study, we have designed more compact signal processing unit compared with the conventional hardware system of multi-path ultrasonic gas flowmeter. We have confirmed its reliability for multi-path ultrasonic gas flowmeter through the laboratory test using calibration system. In the future. we will perform the field test for the developed system in the POSCO gas line.

• Steel and Composite Structures
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• 제27권1호
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• pp.13-25
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• 2018

The main objective of this study is to develop a dual approach for geometrically nonlinear finite element analysis of plane truss structures. The geometric nonlinearity is considered using the Total Lagrangian formulation. The nonlinear solution is obtained by introducing and minimizing an objective function subjected to displacement-type constraints. The proposed method can fully trace the whole equilibrium path of geometrically nonlinear plane truss structures not only before the limit point but also after it. No stiffness matrix is used in the main approach and the solution is acquired only based on the direct classical stress-strain formulations. As a result, produced errors caused by linearization and approximation of the main equilibrium equation will be eliminated. The suggested algorithm can predict both pre- and post-buckling behavior of the steel plane truss structures as well as any arbitrary point of equilibrium path. In addition, an equilibrium path with multiple limit points and snap-back phenomenon can be followed in this approach. To demonstrate the accuracy, efficiency and robustness of the proposed procedure, numerical results of the suggested approach are compared with theoretical solution, modified arc-length method, and those of reported in the literature.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 춘계학술대회 논문집
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• pp.123-127
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• 2004

선박의 접안 시 현재 중ㆍ대형 선박은 체계화된 접안 시스템 없이 주선박의 선수와 선미 및 예인선에서 무전기를 이용한 통신에 의존하여 선박을 접안하고 있다. 본 논문에서는 이를 보완하고자 DGPS를 이용한 선반접안 시뮬레이tus 시스템을 설계하고자 한다. 주선박의 서버는 경ㆍ위도 좌표 값, 헤딩, 속도 등의 정보를 이용하여 선박과 부두와의 거리, 진행방향등을 구하고, 예인선과의 실시간 위치정보의 공유를 통한 정밀측정으로 안전하게 접안을 유도한다. 주 선박 및 예인선의 조타수는 PDA의 클라이언트 프로그램으로 실시간 전송되는 선박의 상태 및 각종 정보를 통해 진행상황을 알 수 있다. 또한, 시뮬레이션 프로그램으로 계산된 선박의 유도경로 데이터를 데이터베이스화하여 최적의 접안 경로를 제시함으로써, 기존의 접안환경보다 정밀한 상황 판단의 방법을 제시하였다.

• 지능정보연구
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• 제25권3호
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• pp.179-200
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• 2019

구전(Word-of-Mouth) 활동은 오래 전부터 기업의 마케팅 과정에서 중요성을 인식하고 특히 마케팅 분야에서 많은 주목을 받아왔다. 최근에는 인터넷의 발달에 따라 온라인 뉴스, 온라인 커뮤니티 등에서 사람들이 지식과 정보를 주고 받는 방식이 다양해지면서 구전은 후기, 평점, 좋아요 등으로 입소문의 양상이 다각화되고 있다. 이러한 현상에 따라 구전에 관한 다양한 연구들이 선행되어왔으나, 이들을 종합적으로 분석한 메타 분석 연구는 부재하다. 본 연구는 학술 빅데이터를 활용해 구전 관련 연구동향을 알아내기 위해서 텍스트 마이닝 기법을 적용하여 주요 연구들을 추출하고 시기별로 연구들의 주요 쟁점을 파악하는 기법을 제안하였다. 이를 위해서 1941년부터 2018년까지 인용 데이터베이스인 Scopus에서 'Word-of-Mouth'라는 키워드로 검색되는 총 4389건의 문헌을 수집하였고, 영어 형태소 분석과 불용어 제거 등 전처리 과정을 통해 데이터를 정제하였다. 본 연구는 학문 분야의 발전 궤적을 추적하는 데 활용되는 주경로 분석기법을 적용해 구전과 관련된 핵심 연구들을 추출하여 연구동향을 거시적 관점에서 제시하였고, 단어동시출현 정보를 추출하여 키워드 간 네트워크를 구축하여 시기별로 구전과 관련된 연관어들이 어떻게 변화되었는지 살펴봄으로써 연구동향을 미시적 관점에서 제시하였다. 수집된 문헌 데이터를 기반으로 인용 네트워크를 구축하고 SPC 가중치를 적용하여 키루트 주경로를 추출한 결과 30개의 문헌으로 구성된 주경로가 추출되었고, 연관어 네트워크 분석을 통해서는 시기별로 온라인 시대, 관광 산업 등 다양한 산업군 등 산업 변화가 반영돼 시대적 변화와 더불어 발전하고 있는 학술적 영역의 변화를 확인할 수 있었다.

• 전기의세계
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• 제26권4호
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• pp.54-60
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• 1977

The feedback sources of oculomotor control system consist of three types of feedback path originating from retinal image displacement, in the proprioceptive fibers of the extraocular muscles, in the efference copy within the C.N.S. From above feedback loops, the retinal image feedback path is a main subject in this experiment. The electrical output of eye ball motion detecting with a photo-electric matrix method is fed into galvanometer through the external feedback path, and the stability was also examined.

• 한국정밀공학회지
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• 제27권10호
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• pp.34-39
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• 2010

We developed a path algorithm for ultrafast/wide area laser processing. Demands for high precision laser processing with a wide area has been increasing for a number of applications such as in solar cell battery, display parts, electronic component and automobile industry. Expansion of the area in which laser processing is an important factor to handle the ultrafast/wide area processing, it will require a processing path. Processing path is path of 2- axis stage and stage of change in velocity can be smooth as possible. In this paper, we proposed a smoothingnurbs method of improved speed profile. This method creates soft path from edge part, it is main purpose that scan area ($50mm{\times}50mm$) inside processing path makes path of topology of possible straight line. We developed a simulation tool using Visual C++.