• Title/Summary/Keyword: Spring-go

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A Performance test of Stirling Cryocooler by Frequency Characteristics (스터링 냉동기의 주파수 특성에 의한 성능평가에 관한 연구)

  • Park, Seong-Je;Hong, Yong-Ju;Kim, Hyo-Bong;Go, Deuk-Yong;Go, Gun-Seop;Kim, Jong-Hak
    • 연구논문집
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    • s.30
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    • pp.25-32
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    • 2000
  • A free piston and free displacer(FPFD) Stirling cryocooler for cooling infrared and cryo-sensors is currently under development at KIMM(Korea Institute of Machinery & Materials). A Stirling cryocooler is relatively compact, reliable, commercially available, and uses helium as a working fluid. The FPFD stirling cryocooler consists of two compressor pistons driven by linear motors which makes pressure waves and a pneumatically driven displacer piston with regenerator. The FPFD Stirling cryocooler employs 1) the Stirling cycle for refrigeration, 2) linear for driving the cryocooler, 3) spring and gas support systems, and 4) fine gap for clearance seals. It is the most suitable design for a mechanical cryocooler utilized in night vision environment. In order to get optimum operating frequency, natural frequency of piston and displacer, optimum phase angle between piston and displacer, cooling capacity, performance tests of the Stirling cryocooler by the frequency characteristics were performed.

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THE VARIATIONAL THEORY OF A CIRCULAR ARCH WITH TORSIONAL SPRINGS AT BOTH EDGES

  • Go, Jae-Gwi
    • Journal of the Korean Mathematical Society
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    • v.44 no.3
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    • pp.707-717
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    • 2007
  • Arches are constrained with rotational resistance at both edges. An energy method is used to derive variational formulation which is used to prove the existence of equilibrium states of elastic circular arches for the torsional spring constants ${\rho}-\;{\geq}\;0,\;{\rho}+\;{\geq}\;0,\;and\;{\rho}-\;+\;{\rho}+\;>\;0$. The boundary conditions are searched using the existence of minimum potential energy.

BIFURCATION THEORY FOR A CIRCULAR ARCH SUBJECT TO NORMAL PRESSURE

  • Bang, Keumseong;Go, JaeGwi
    • Korean Journal of Mathematics
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    • v.14 no.1
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    • pp.113-123
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    • 2006
  • The arches may buckle in a symmetrical snap-through mode or in an asymmetry bifurcation mode if the load reaches a certain value. Each bifurcation curve develops as pressure increases. The governing equation is derived according to the bending theory. The balance of forces provides a nonlinear equilibrium equation. Bifurcation theory near trivial solution of the equation is developed, and the buckling pressures are investigated for various spring constants and opening angles.

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A Study on A Web-Based DevOps Platform Using Linux Container (리눅스 컨테이너를 이용한 웹기반의 DevOps 플랫폼 연구)

  • Chung, Geunhoon;Park, Junseok;Lee, Geuk
    • Journal of the Korea Convergence Society
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    • v.10 no.12
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    • pp.71-80
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    • 2019
  • DevOps is a combining which means giving a diverse environments for software development and operations through whole software lifecycle. The key value of the proposed DevOps platform is the fast and stable service capability for a software development and operation environment. To do this, the DevOps gives pre-embedded 7 programming languages-Java, C/C++, Python, PHP, Ruby, Node.js, goLang and 7 service frameworks - Korea eGov Framework, Spring, Struts, Django, Laravel, Rails, Express. With the DevOps platform, it is possible to develop a software and also to build and distribute operation packages directly with the Linux containers. In this paper, the performance evaluation for a compile time, a distribution time and a processing capability is will be also proved. Though the performance evaluation, this paper shows capabilities of the proposed DevOps for Cloud services with commercial service level, prospectively.

The Feasibility Study of Sit-to-stand and Stand-to-sit Assistive Chair for Elderly

  • Seonggwang Yu;Seungmuk Lee;Minsoo Kim;Dae-Sung Park
    • Physical Therapy Rehabilitation Science
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    • v.11 no.4
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    • pp.591-597
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    • 2022
  • Objective: The sitting and standing are motions that correspond to the previous stage of rehabilitation to go to walking for daily life. The purpose of this study was to measure task times, path length of the center of pressure (COP) and activity on the vastus femoris muscle using surface electromyography (EMG) when standing up and sitting down. Design: One group cross-sectional design Methods: Fifteen elderly subjects (8 male, 7 female) participated. All subjects were tested three times according to four assist levels (non-assist, lower, middle, and maximal assist) using adjusts the length of spring at sit-to-stand and stand to sit on a chair. The task duration, and COP path length were recorded for the balance function on the Nintendo Wii fit board. The activity of the rectus femoris muscle was recorded on both legs using surface EMG. Results: The results showed that the task duration of the sit-to-stand and stand-to-sit were significantly increased compared to without assist (p<.05). The activation of the rectus femoris muscle more significantly decreased compared to without assistance at standing or sitting (p<.05). Conclusions: The assistive chair showed less quadriceps muscle activation during sitting and standing compared to without assistance. We suggest that our assist-standing chair can help with activities of daily living such as standing up and sitting down movements adjusting the spring length for control assist level by safely.

A Study on pollution of spring in Incheon Area (인천 지역 약수터의 오염에 대한 연구)

  • Kim, Kyung-Ae;Lee, Byeng-Ok;Kim, Ou-Mok;Hur, Myung-Je;Kim, Kyung-Tae;Ro, Jae-Il;Choe, Choon-Suck;Go, Jong-Myoung;Kim, Yong-Hee
    • Journal of environmental and Sanitary engineering
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    • v.22 no.3
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    • pp.35-50
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    • 2007
  • In order to investigate water pollution of spring, we carried out the experiments on mineral water, rainwater and surrounding soil of several springs collected in Incheon area from February to August in 2007. The results were as follows. 1. Soil : This study investigated the pH and organic matter contents in the soil which effect on microorganisms. The pH value was from 4.5 to 5.3 on average and organic matter contents ranged from 1.09% to 5.6% and E. coli, K. pneumoniae, S. faecalis and other microorganisms were isolated. 2. Natural mineral water : As the rainfall increased, the concentration of $No_3-N$, consumption of $KMnO_4$ and the number of microorganisms was increased while the other physicochemical items were not affected. The microorganism isolated in the natural mineral water were as follows: E. coli, K. oxytoca S. faecalis, S. facium, and so on from evacuation; E. agglomerans, E. amnigenus, E. cloacae, E. sakazakii and so on from the environments and evacuation. Detection of these microorganisms shows that the environment around the spring had been exposed to excrements of the warm blood animal. 3. Rain : The coliforms in the rain were the identical one detected from the mineral water and the soil. In conclusion the quality of natural mineral water is influenced by rain, resident bacteria of soil and surrounding environment. This study will be the basic data of characteristics of spring in Incheon area and also this result will give useful aids for the efficient control of spring.

A Haptic Navigation System for Visually Impaired Persons (시각장애인을 위한 햅틱 네비게이션 시스템)

  • Kim, Sang-Youn;Cho, Seong-Man
    • Journal of Korea Multimedia Society
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    • v.14 no.1
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    • pp.133-143
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    • 2011
  • This paper proposes a mobile navigation system which haptically presents the way to go to visually impaired persons. In order to convey the tactile information to the visually impaired persons, we develop a new tactile module with a solenoid, a permanent magnet and an elastic spring. Furthermore, we suggest 2D vibration flow which originates from one point and gradually propagates to other points on a surface of the haptic navigation system. The tactile module and the vibration flow method are incorporated into the proposed haptic navigation system and they stimulate the user's finger pad and palm, respectively. We conduct experiments to investigate that the proposed navigation system haptically provides the direction to the users. From the experimental results, we verify that the proposed system can generate enough tactile sensation to guide the direction to go in real-time.

Two-Dimensional Hydraulic and Numerical Modeling of tidal Currents in Chinhae Bay (鎭海灣 潮流의 2차월 水利 및 數値 모델링)

  • 김차겸;장선덕
    • 한국해양학회지
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    • v.29 no.2
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    • pp.83-94
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    • 1994
  • Two-dimensional tidal and tidal residual currents in Chinhae Bay are investigated by field observations, hydraulic and numerical experiments. The results of hydraulic and numerical model experiments roughly coincide with the field measurements. Maximum tidal currents during the spring and neap tides in Kaduk and Kyunnaeryang channel and the central channel of Chinhae Bay are strong as 90 to 110 and 30 to 40 cm/s respectively, and strong tidal residual currents having numerous eddies take place. Maximum tidal currents during the spring and neap tides in the western and northern parts of the bay are weak as below 30 and 10 cm/s respectively, and also tidal residual currents are relatively weak. Tidal residual currents in the northern part of Kajo-do go toward the north, whereas the currents in the southern part move down the bay, and the currents rotating clockwise occur around Bu-do. The surface currents in the bay depend strongly on the wind and river inflow, and such phenomena are more remarkable during he neap tide than the spring tide.

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A Study on Lateral Damper for Improving Running Performance of Subway Vehicle (도시철도 전동차 주행성능 향상을 위한 횡댐퍼에 관한 연구)

  • Jeon, Ju-Yun;Hur, Hyun-Moo;Shin, Yu-Jeong;You, Won-Hee;Koo, Jeong-Seo
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1856-1861
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    • 2011
  • As a secondary suspension, the air spring has not good lateral stiffness characteristics. In order to make up for this weak point, lateral damper is used between bogie and carbody. The lateral vibration of carbody can be reduced by the lateral damper. When the damping force of lateral damper becomes worse, the running stability and ride comfort of the railway vehicle go down. Simultaneously the lateral motion of carbody is increased. In this study, the lateral displacement of carbody was studied by the multibody dynamic analysis in accordance with lateral damping force to find the cause of abnormal noise(impact noise) when the vehicle is running. The suitable lateral damping force was reviewed in order not to generate abnormal noise.

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Branded Apartment Images and Families with Different Children Ages (자녀 연령에 따른 브랜드 아파트 이미지 선호)

  • Lee, Jee-Young;Chang, Jee-Hae;Go, Jong-Chul;Lee, Hyun-Jeong;Lee, Yeun-Sook
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • 2004.11a
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    • pp.105-109
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    • 2004
  • The purpose of this study is to find out branded apartment images families with different children ages favored. On-line survey was conducted in the Seoul Metropolitan Areas, and the 181 responses were used for the data analysis. Four children age cohorts were applied to describe favorable branded apartment images - families with infants or toddlers, elementary school children, adolescents and college students. The finding indicated that the respondents preferred branding apartments mainly because it was likely to reflect quality. Also it was found that the most favorable branded apartment image was safety, and the investment-related image was favored by families with young children while the image of comfort by those with adolescents. Families with kids preferred the image of environmental friendliness, those with did a health-related image, and the other two groups did the safety image.

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