• Journal of Advanced Marine Engineering and Technology
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• 제36권2호
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• pp.267-275
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• 2012

본 논문은 정상풍속과 돌발풍속을 수학적으로 모델링하고 풍향에 따라 전달되는 메인축에서의 전달모멘트를 조사하여 기어박스에 전달되는 풍하중의 특성을 파악하였다. 정상풍속은 지상에서 고도가 높아짐에 따라 속도가 증가하게 설정을 하였다. 풍하중에 의해서 메인축으로 전달되는 모멘트의 평균값과 하모닉값을 풍향 입사각을 $-45^{\circ}{\sim}45^{\circ}$로 변화를 주며 특성을 파악하였다. 또한 기어 트레인의 미스 얼라인먼트를 유발시키는 굽힘 모멘트의 특성을 파악하였다. 정상풍속모델에서는 블레이드의 3배수 주파수(3X)로 하는 토크의 가진이 생기며, 바람의 방향이 $+22.5^{\circ}$일 때 수평방향의 굽힘 모멘트가 주축으로 들어가는 토크의 50%수준으로 발생하는데 이는 수평방향으로의 탄성 축 휘임을 유발하여 치가 모서리에서 물림이 발생하게 하는 원인을 제공함을 알 수 있었다. 돌발풍속의 경우, 3X, 6X, 9X를 가진 주파수로 하는 토크의 가진이 바람의 방향이 +방향으로 커질수록 하모닉항의 상대 비율이 증가하였다.

• 한국지역지리학회지
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• 제11권3호
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• pp.351-366
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• 2005

조선시대의 관도(官道)는 당시 지리지들의 기술방식으로도 짐작할 수 있듯이, 수도 한양과 지방의 각 고을 및 군사요충지를 직결하는 것을 제일의 목적으로 하고 있었다. 바꾸어 말하면 지방행정도시인 읍치와 수도는 관도를 통해 가장 가깝게 연결되어 있었던 것이다. 관도는 공무여행자의 정식통로이자 관리의 파견 및 귀경통로였다. 따라서 이 관도가 읍치로 접어드는 지점이 보통 그 해당 읍치의 현관문이 되는 것이었다. 한편 지형적 제약 등이 없는 한 대부분의 읍치에서는 관아의 좌향이 남향이었기 때문에, 이를 마주보는 남쪽 출구가, 읍성이 있으면 남문이 으레 읍치의 현관문이 되었다. 따라서 판도는 읍치 주변을 우회해서라도 남문으로 돌아서 읍치에 들어가도록 고지도 등에는 그려지고 있는데, 이는 실제적인 교통로의 체계와 차이가 날 수 있는 '상징적 교통로'였다. 관아와 현관문 사이, 때로는 주산, 내삼문, 외삼문, 비보 등의 요소까지 추가되어서 해당 읍치의 상징축이 형성되었다. 다만 역시 지형이나 교통로의 방향 때문에 실제 공간상에서는 상징축의 방향과 교통로의 방향, 심지어 현관문의 위치까지도 실제와 어긋나는 경우도 많았다.

• 융합신호처리학회논문지
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• 제6권4호
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• pp.191-197
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• 2005

2족 보행을 특징으로 하는 인간형 로봇은 구동해야할 관절의 수가 매우 많으며, 로봇의 보행 상태 등을 인식하기 위하여 다양한 센서의 활용이 필요하다. 본 논문에서는 21개의 RC 서보 모터를 사용한 소형의 2족 보행 로봇의 제어기의 구조를 제안하고 구현한다. 제안된 제어기는 호스트 PC와 DSP를 사용한 주 제어기, 그리고 FPGA를 사용한 보조 제어기의 계층 구조를 갖는다. 호스트 PC에서는 보폭, 보행 시간 등과 같은 보행 파라미터에 따른 로봇의 보행 데이터를 생성하여 주 제어기로 전송하고, TI사에서 제어용으로 출시된 DSP 칩인 TMS320LF2407A를 사용하여 구현된 주 제어기에서는 보조 제어기를 통하여 21개의 RC 서보 모터를 구동한다. 또한 주 제어기와 2축 가속도 센서를 인터페이스하여 보행 바닥면의 경사도에 따른 균형잡기 실험과 기울어진 바닥면의 기울기를 검출하여 경사면 보행이 가능함을 보인다.

• 한국기계가공학회지
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• 제19권12호
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• pp.62-69
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• 2020

The demand for industrial robots is proliferating with production automation. Industrial robots are used in various fields, such as logistics, welding, and assembly. Generally, six degrees of freedom are required to move freely in space. However, the palletizing robot used for material management and logistics systems typically has four degrees of freedom. In designing such robots, their main parts, such as motors and reducers, need to be adequately selected while satisfying payload requirements and speed. Hence, this study proposes a practical method for selecting the major parts based on dynamic analysis using ADAMS. First, the acceleration torques for the robot motion were found from the analysis, and then the friction torques were evaluated. This study introduces a constant-speed torque constant instead of friction coefficient. The RMS torque and maximum power of each motor were found considering the above torques. After that, this study recommends the major specifications of all motors and reducers. The proposed method was applied to a palletizing robot to verify the suitability of the pre-selected main parts. The verification result shows that the proposed method can be successfully applied to the early design stage of industrial robots.

• 한국소음진동공학회논문집
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• 제25권4호
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• pp.238-246
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• 2015

A stepping motor is widely used to operate the elevation and azimuth stage of the X-band antenna with 2-axis gimbal system for effective image data transmission from a satellite to a ground station. However, such stepping motor also generates an undesirable micro-vibration which is one of the main disturbance sources affecting image quality of the high-resolution observation satellite. In order to improve the image quality, the micro-vibration isolation of the X-band antenna system is essential. In this study, the low rotational stiffness isolator has been proposed to reduce the micro-vibration disturbance induced by elevation direction operation of the X-band antenna. In addition, its structural safety was confirmed by the structure analysis based on the derived torque budget. The effectiveness of the design was also verified through the micro-vibration measurement test.

• Structural Engineering and Mechanics
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• 제49권2호
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• pp.273-283
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• 2014

According to deformation features of pre-twisted bar, its elastic bending and torsion buckling equation is developed in the paper. The equation indicates that the bending buckling deformations in two main bending directions are coupled with each other, bending and twist buckling deformations are coupled with each other as well. However, for pre-twisted bar with dual-axis symmetry cross-section, bending buckling deformations are independent to the twist buckling deformation. The research indicates that the elastic torsion buckling load is not related to the pre-twisted angle, and equals to the torsion buckling load of the straight bar. Finite element analysis to pre-twisted bar with different pre-twisted angle is performed, the prediction shows that the assumption of a plane elastic bending buckling deformation curve proposed in previous literature (Shadnam and Abbasnia 2002) may not be accurate, and the curve deviates more from a plane with increasing of the pre-twisting angle. Finally, the parameters analysis is carried out to obtain the relationships between elastic bending buckling critical capacity, the effect of different pre-twisted angles and bending rigidity ratios are studied. The numerical results show that the existence of the pre-twisted angle leads to "resistance" effect of the stronger axis on buckling deformation, and enhances the elastic bending buckling critical capacity. It is noted that the "resistance" is getting stronger and the elastic buckling capacity is higher as the cross section bending rigidity ratio increases.

• 간호행정학회지
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• 제8권4호
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• pp.669-689
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• 2002

Purpose : The purpose of the present study is to develop a clinical pathway applied with activity-based management methodology for efficient clinical management to cope with rapid changing medical environments. Method : After making a preliminary pathway based on which a conceptual frame of reference was established to develop a clinical pathway, the final one was confirmed by verifying experts validity and clinical validity. The ultimate activity-based clinical pathway was restructured after clarifying, schematizing and analyzing the whole activities of clinical pathway in accordance with the conducting process of activity-based management. Result : A clinical pathway for total hip replacement was developed, in which the vertical axis consisted of assessment, examination, consultation, medication, treatment, diet, activity, and education, and the horizontal axis was composed of six days of hospitalization. Then, on the basis of the development, the clinical pathway including the improved contents and information was restructured after making the reform measure by analyzing each of activities in the pathway. And the list of contents related to the clinical management activity was made, which was described its main contents and the pre-activities that ought to be completed before conducting each of activities in the pathway. Conclusion : The clinical pathway applied with activity-based management may be used as a standard guidance for providing continuous and consistent patient care. It will provide the information for nursing activities to nurses and the management information about hospital and nursing activities to the hospital administrators. It will also be used as a tool for communication between medical staff. Besides, it will contribute to creating profits for the hospital by shortening the length of stay in patients.

• 건축역사연구
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• 제20권6호
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• pp.169-184
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• 2011

The following research of the road network of Jeju-Eupseong during Daehan Empire period has a twofold purpose: to study some characteristics of the road network at that time; and, to restore it to the original form of that period before a newly constructed road, called Shinjakro, has been established. As an attempt to trace the old shape of Jeju-Eupseong, this study analyzed some historical factors based on the first land cadastral map which was made in 1914, including outskirts of Jeju-Eupseong; such as castle itself, castle gate, road, bridge, lots of land, etc. Then this study also tried to restore the old road network of Jeju-Eupseong, through finding the original land-lot shape in the land cadastral map. There was five Shinjakro made between 1914 and 1917. The road network before then was composed of the double east-west axes and the single north-south axis. These axes was connected to some important place of the inside of Jeju-Eupseong; such as castle gates, fountains, Gaek-sa, etc. There were many branch lines between these main axes at about 80-120m intervals. Also there was an outer road along the outer wall of castle, connected with each castle gates. Especially, the north-west axis was the baseline which divided into two large parts, a government office area and non-government area (housing and commercial street for the people). Finally, this paper examines that the road network of Jeju-Eupseong was the true result for the efficient function of the city, especially considering natural geographical conditions and environment of living of that time.

• 천문학회지
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• 제50권3호
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• pp.51-59
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• 2017

The presence of blue stragglers pose challenges to standard stellar evolution theory, in the sense that explaining their presence demands a complex interplay between stellar evolution and cluster dynamics. In the meantime, mass transfer in binary systems and stellar collisions are widely studied as a blue straggler formation channel. We explore properties of the Galactic open clusters where blue stragglers are found, in attempting to estimate the relative importance of these two favored processes, by comparing them with those resulting from open clusters in which blue stragglers are absent as of now. Unlike previous studies which require a sophisticated process in understanding the implication of the results, this approach is straightforward and has resulted in a supplementary supporting evidence for the current view on the blue straggler formation mechanism. Our main findings are as follows: (1) Open clusters in which blue stragglers are present have a broader distribution with respect to the Z-axis pointing towards the North Galactic Pole than those in which blue stragglers are absent. The probability that two distributions with respect to the Z-axis are drawn from the same distribution is 0.2%. (2) Average values of $log_10(t)$ of the clusters with blue stragglers and those without blue stragglers are $8.58{\pm}0.232$ and $7.52{\pm}0.285$, respectively. (3) The clusters with blue stragglers tend to be relatively redder than the others, and are distributed broader in colors. (4) The clusters with blue stragglers are likely brighter than those without blue stragglers. (5) Finally, blue stragglers seem to form in condensed clusters rather than simply dense clusters. Hence, we conclude that mass transfer in binaries seems to be a relatively important physical mechanism of the generation of blue stragglers in open clusters, provided they are sufficiently old.

• 한국조경학회지
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• 제34권4호
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• pp.61-68
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• 2006

A park will soon be developed in an area of Gwangjang-dong, Gwangjin-gu. The place has been a patch of green space for years, isolated by driveways and apartment complexes and abandoned. This article describes plans to infuse the abandoned green space with history, ecology, culture, and sports. The facilities that are to be constructed in and around the green space are positioned to take into account the path of the sun and the location of the curvilinear green space axis. The cultural space is planned as a centerpiece of the park, linked with the sports facilities. The overall framework is arranged in harmony with nearby elementary schools, parks, public facilities, athletic facilities, parking lots, and apartment complexes. The themed circulation route was constructed according to the environmental conditions and the spatial plan. In addition, the historical space is planned to work in close conjunction with the cultural space, and the streets and pedestrian pathways have characters of their own. The established contour lines will be carefully preserved, and an ecological pond will. The facilities, such as the outdoor performance stage, the outdoor art gallery, the Monument of Wind represented by a sail, and the pedestrian bridge in memory of Acha-sansung, are positioned for spatial balance and to provide a nexus. The bamboo forest, designed to foster the experience of sound effects, the architectural thematic plants, and the ecological pond are positioned to connect to each other around the greenspace axis. The main facilities are the outdoor theater, the bamboo forest, the Acha-sansung bridge, the Monument of Wind, the ecological pond, the four-season flower garden, parking lots, playgrounds, circulatory athletic pathways, and the tennis court.