• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1720-1721
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• 2007

This paper presents a Fuzzy+PID control method for a Bridge Inspection Robot(BIR) system. The BIR has been developed with the aim of checking the safety status of a real bridge, gathering accurate data and performing maintenance. The developed robot system is composed of the specially designed car for bridge inspection, the guide rail and the inspection robot. The proposed Fuzzy+PID controllers are used to track speed reference signal of X axis and position reference signal of Z axis. Experimental results verify that the proposed Fuzz+PID control design method can achieve favorable control performance with regard to external disturbance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.802-805
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• 2003

The aim of this paper is to provide a guide to those methods of train detection which are available, or are likely to become available, to the designer of train control or other relevant systems. In broad terms, train detection may be defined as the process of generating information which describes the location and movement of trains. Train detection information is difficult to define in isolation. Consider, for example, the train detection information required in a modern train control system. This may vary considerably : in a future high performance train control system, it might be necessary to know the precise position, direction of movement, speed, and possibly even the acceleration or braking, of all trains in the control area : in a less demanding application, it might be sufficient to know only the location of trains in terms of the occupation of sections of track.

• 한국초등과학교육학회지:초등과학교육
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• 제35권4호
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• pp.389-405
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• 2016

The purpose of this study was to analyze elementary school teachers' understanding, certainty, and familiarity with 13 key concepts of wave physics that are presented in textbook and teacher's guidebook. 123 elementary school teachers answered concept tests and questionnaires. In the results to these tests and questionnaires, teachers demonstrated a high level of understanding and high certainty in understanding with regard to the concepts of sound generation, effect of medium on wave, timbre, wavelength, and trough and crest of wave. For the topics of sound velocity, wave reflection and wave transmission, teachers demonstrated a high level of understanding but low certainty in understanding. With regard to sound propagation, teachers demonstrated a low level of understanding and an improperly high certainty in that low understanding. Teachers lacked knowledge, i.e., displayed a low level of understanding and low certainty in sound strength, sound frequency, constructive interference and destructive interference. In constructive and destructive interference, the teachers also displayed a low level of familiarity. We analyzed the differences in teacher's understanding, certainty, and familiarity according to teacher demographics defined by the teacher's gender, teaching experience with concepts of sound, career, curriculum track while in high school, and major in university. There were no significant differences in understanding, certainty, or familiarity as defined by gender, teaching experience, and career. However, these displays of knowledge were affected by the teacher's curriculum track in high school and their major. These results suggest that the teacher's understanding of, familiarity with, and certainty in wave physics concepts are more influenced by their learning experience than by their teaching experience. Therefore, we suggest additional learning opportunities for teachers (such as teacher training programs) in order to improve teacher knowledge and correct teacher misconceptions in wave physics.

• 전자공학회논문지
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• 제54권4호
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• pp.129-134
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• 2017

현대 사회에서 최근 우리나라의 베이커리 산업관련 기술은 빵이 시작된 서양과 어깨를 나란히 할 만큼 성장하여 제과제빵분야의 세계대회에서 최상위권으로 입상하는 등 눈부시게 발전 하고 있다. 그래서 많은 사람들이 제과제빵분야와 베이커리 카페 등의 부가가치가 높은 사업에 관심을 갖고 뛰어들고 있는 추세이다. 하지만 기술자들의 높은 인건비와 인력관리의 어려움은 베이커리 산업의 성장에 저해요소가 되고 있다. 따라서 밀반죽을 빠르고 정확하게 분할과 둥글리기를 동시에 수행하는 시스템을 설계하고 제작하여 수작업과 비교된 성능을 알아보았다. 주요 기능은 밀반죽의 분할 개수를 원형에서 3개의 트랙으로 만들고 안쪽 트랙에 4개, 중간트랙에 12개, 외각트랙에 20개를 배치하여 36개이다. 한 번의 루틴에서 36개가 완성되므로 많은 양의 에너지가 필요하기 때문에 유압을 이용하였고 둥굴이기는 0.75Kw의 유도전기를 사용하였다. 본 시스템의 실험은 1차 발효를 마친 밀반죽으로 하였다. 밀반죽 36개 합산 량의 덩어리를 본 시스템에서 작업을 하면 36개로 분할과 둥굴이기가 동시에 완성된다. 분할시간 1-9초 사이, 둥굴이기 시간 1-9초 사이로 매우 빠르고 정확하게 완성 된다. 본 시스템은 인력수급이 어려운 베이커리산업에 인건비 절감에 매우 효과적이고 좀 더 위생적으로 만든 제품을 소비자에게 공급할 수 있을 것으로 기대된다.

• 한국항행학회논문지
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• 제15권5호
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• pp.839-844
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• 2011

기존의 위치인식 시스템을 활용한 방법으로는 적외선, 초음파, RFID, GPS, UWB, 신호 세기 등을 이용한 방법이 있지만, 각 시스템은 음영지역에서의 위치인식이 필요하다. 본 논문에서는 협력 스펙트럼 센싱(Cooperative Spectrum Sensing)을 이용해 사물이 움직이는 경로와 위치를 판단하고, 센서가 위치한 정해진 경로를 이탈할 경우에 이를 인지해 정상적인 경로로 이동할 수 있도록 도와준다. 협력 스펙트럼 센싱은 1차 사용자에게 간섭 영향을 미치지 않는 범위 내에서 전파인지 사용자에게 최적의 전송 전력과 변조 레벨을 결정할 수 있기 때문에 주파수의 사용 효율을 높일 수 있다. 본 논문에서는 협력 스펙트럼 센싱 기법을 이용한 위치인식 시스템을 제안하였다.

• 한국정밀공학회지
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• 제31권9호
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• pp.783-790
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• 2014

Railway wheels and axles are the most critical parts of the railway rolling stock. The wheel carry axle loads and guide the vehicles on the track. Therefore, the contact surface of wheel are subjected to wear and fatigue process. The wheel damage can be divided into three types; wear, contact fatigue failure and thermal crack due to braking. Therefore, in the contact surface between the wheel and the rail, the materials are heat treated to have a specific hardness. The manufacturing quality of the wheel have a considerable influence on the formation of tread wear and damage. Also, the residual stress on wheel is formed during the manufacturing process is one of the main sources of the damage. In this paper, the mechanical characteristic and the residual stress according to wheel material have been evaluated by applying finite element analysis and conducting mechanical tests.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1249-1254
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• 2010

중앙 안내방식의 모노레일대차 구조는 세계최초로 인천 월미모노레일에 적용되었으며, 대차프레임 소재 또한 우리나라에서는 최초로 알루미늄 재질을 사용하였다. 대차는 수직하중과 수평하중을 노면과 가이드 레일에 전달하는 중요한 시스템으로서 내구성이 충분한 구조를 가지고 있어야 할 뿐만 아니라, 우수한 주행 성능과 승차감이 확보되어야 한다. 본 논문에서는 중앙 안내방식의 모노레일에 적합한 대차 구조를 비롯하여 대차의 주행성능 및 승차감을 확보할 수 있는 시스템 구성 방법은 물론 대차프레임의 내구성을 향상 시킬 수 있는 방안에 대해 제시하였다.

• 로봇학회논문지
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• 제12권4호
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• pp.411-418
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• 2017

During the intramedullary nailing procedure, surgeons feel difficulty in manipulation of the X-ray device to align it to axes of nailing holes and suffer from the large radiation exposure from the X-ray device. These problems are caused by the fact the surgeon cannot see the hole's location directly and should use the X-ray device to find the hole's location and direction. In this paper, we proposed the robotic guidance of the distal screwing using an optical tracking system. To track the location of the hole for the distal screwing, the reference marker is attached to the proximal end of an intramedullary nail. To guide the drill's direction robustly, the 6-degree-of-freedom robotic arm is used. The robotic arm is controlled so as to align the drill guiding tool attached the robotic arm with the obtained the hole's location. For the safety, the robot's linear and angular velocities are restricted to the predefined values. The experimental results using the artificial bones showed that the position error and the orientation error were 0.91 mm and $1.64^{\circ}$, respectively. The proposed method is simple and easy to implement, thus it is expected to be adopted easily while reducing the radiation exposure significantly.

• Journal of Information Science Theory and Practice
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• 제10권4호
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• pp.87-109
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• 2022

Previous studies have found that the use or development of theory in library and information science (LIS) research is comparatively low and may be trending downward. LIS has also been criticized for relying on theories imported from other disciplines rather than applying or developing theories from within. The theory of information worlds, a social information behavior theory originally introduced in 2008, represents a newer LIS theory whose level of adoption is understudied. This study features a systematic literature review of peer-reviewed research articles which cited or used the theory of information worlds from 2008 to early 2022 to identify trends related to levels of theory use, publication venues, author affiliations, countries, and collaborations, as well as research methods, topics, and populations. Findings suggest that both awareness and use of the theory of information worlds are positively trending, though at slower rates for higher levels of theory use, such as full applications of the theory to guide the collection and analysis of empirical data. The theory has also been used by researchers from around the world and across disciplines, most often with mixed and qualitative methods. While the growth of a new LIS theory is promising, the authors echo calls for increased use and development of the theory of information worlds, and other LIS theories more broadly, and as more interdisciplinary collaboration.

• Steel and Composite Structures
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• 제49권2호
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• pp.125-141
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• 2023

Firstly, a new kind of prismatic tensegrity structures with redundant cables is defined, the topology, geometry and forming conditions of which are introduced further. The development of its mechanical properties including self-stress states and structural stiffness with the increment of the twist angle is also investigated carefully. Combined with the topology of this kind of structures, a reasonable erection scheme is proposed, in which some temporary lifting points need to be set and two groups of vertical cables are tensioned in batches. Then, a simplified dynamic relaxation method is employed to track the erection process inversely, which aims to predict each intermediate equilibrium state during the construction, and give the key structural parameters that can effectively guide the construction. The removal of the active cables, the relaxation or tension of the passive cables are simulated by controlling their axial stiffness, so that the structural composition as well as the serial numbers of the elements always keep invariant regardless of the withdrawal of the slack cables. The whole analysis process is clear in concept, simple to implement and easy to popularize. Finally, several examples are given to verify the practicability and effectiveness of the proposed method further.