• Title/Summary/Keyword: Ground Condition

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Comparison of characteristics during backward walking according to various stride frequencies in underwater and ground environments

  • Kim, Heejoong;Chung, Yijung
    • Physical Therapy Rehabilitation Science
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    • v.7 no.2
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    • pp.83-87
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    • 2018
  • Objective: The purpose of this study was to investigate the relationship between heart rate (HR), self-awareness of exercise intensity (rating of perceived exertion, RPE), and 5-meter walk test (5MWT) of persons affected by stroke during backward walking according to the preferred stride frequency (PSF), PSF+3 and PSF+6 conditions. Design: Cross-sectional study. Methods: A total of 11 persons with stroke (9 males, 2 females) participated voluntarily. All patients underwent backward walking under the PSF, PSF+3, and PSF+6 conditions in underwater and ground environments, and each condition was performed for 5 minutes. The HR, RPE, and walking speeds were measured during walking, and the measured values from underwater and ground environments were compared. Results: The HR and RPE in the ground environment were significantly increased (p<0.05), and although the 5MWT showed an increase in speed, it was not significant. The HR and RPE in the underwater environment were also significantly increased (p<0.05), however, although the 5MWT results was increased, it was not significant. The HR and RPE were significantly increased in the PSF+6 condition (p<0.05). Conclusions: The results of this study showed that backward gait training underwater can provide an appropriate exercise intensity for stroke survivors and suggests that exercises performed in an underwater environment is more effective compared to the ground environment.

Ground-Tunnel Interaction Effect Depending on the Ground Stiffness (지반의 강성변화에 따른 지반-터널 동적 상호작용 연구)

  • 김대상
    • Tunnel and Underground Space
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    • v.11 no.4
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    • pp.339-343
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    • 2001
  • Shield tunnel having circular section located in the soil or soft rock layer is liable to deform in such a way that its two diagonal diameters crossing each other expand and contract alternately during earthquakes. Based on this knowledge, the ground-tunnel interaction effect for this particular vibration mode is investigated. The ground surrounding a tunnel is assumed to be a homogeneous elastic medium. The bonded boundary condition on the ground-tunnel interface is considered. This suggests a firm bond between the ground and the tunnel lining. As Poisson's ratio and stiffness of the ground increases, the strain induced within the tunnel lining increases.

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Utilization of the Information of Fishing and Sea Condition for Common Squid (Todarodes pacificus) Using Angling in the East Sea: Relationships between Fishing Ground and Sea Temperature (동해 오징어(Todarodes pacificus) 채낚기어업의 어·해황정보의 유효이용 -어장형성과 수온과의 관계-)

  • Jeong, Dong-Gun;Rho, Hong-Kil
    • Journal of Fisheries and Marine Sciences Education
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    • v.10 no.1
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    • pp.31-52
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    • 1998
  • In this paper, we analyzed the relationships between the fishing ground formation and the sea condition information, surface, mid and bottom layer temperature that is necessary for fishing point selection of angling to catch squid in the East Sea. There was a little differences between temperature measured by every fishing boat on fishing operating and prompt reports of fishing and sea condition about fishing ground formation of angling. And then the result examined by using SST that is a important information of sea condition for the fishing position selection follows as ; We knew, even if the differencs of sea condition each year, SST with a lot of fishing boats was generally within the extnet of $2^{\circ}C$. But the result examined by the limit time about the temperature of mid and bottom layer for the groups of fishing boats not to measure and for the near sea measurement to be done only within EEZ waters follows as ; About the temperature of 50m layer on early in June and July in operating waters of the group of fishing boats, the fishing ground was formed from $10^{\circ}C$ to $12^{\circ}C$ between warm waters and cold waters, afterwards we can seize that the fishing ground was moving to waters from $5^{\circ}C$ to $8^{\circ}C$ at near of polar front. In the coastal waters, we knew that fishing ground is formed to waters from $10^{\circ}C$ to $12^{\circ}C$ at the southern of polar front about the temperature of 50m layer.

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Ground Stability Interpretation of the Five-storied Stone Pagoda at the Muryangsa Temple, Korea; An Examined by the Nondestructive Survey (비파괴 탐사를 이용한 무량사오층석탑 지반안정해석)

  • Chae, Sang-Jeong;Suh, Man-Cheol
    • Journal of Conservation Science
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    • v.20
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    • pp.43-54
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    • 2007
  • The Muryangsa temple five-storied stone pagoda (Treasure No. 185) was geographically located in the area of the Baekje Kingdom. The architectural style of the Muryangsa temple five-storied stone pagoda is the pagoda at the early Goryeo Dynasty that was succeeded technique of the Baekje Kingdom and form of the Shilla Kingdom. Because this pagoda is located outside during old time that it received serious petrological and biological weathering in rock blocks and occurred the center subsidence in the upper capstone. This study executed ground stability interpretation in order to know what central subsidence in the upper capstone occurred for soft ground. The ground stability interpretation used seismic survey, electrical resistivity survey and GPR survey by non-destructive method. As the result, the ground appeared in the condition which is good. Specially, high resistance zone appeared from electric resistivity survey which come to seem with ground reinforcement harden. Consequently, central subsidence condition in the upper capstone is not by the instability of ground, and is judged with the thing by the structure instability in rock blocks over the upper capstone. This will be applied basic data with the long-term monitoring or preservation countermeasure of the pagoda.

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Influence of Rotating Wheel and Moving Ground Condition to Aerodynamic Performance of 3-Dimensional Automobile Configuration (돌아가는 바퀴 및 이동지면 조건이 3차원 자동차 형상의 공력성능에 미치는 영향에 관한 연구)

  • Kang, Seung-On;Jun, Sang-Ook;Park, Hoon-Il;Ku, Yo-Cheon;Kee, Jung-Do;Hong, Dong-Hee;Kim, Kyu-Hong;Lee, Dong-Ho
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.5
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    • pp.100-107
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    • 2010
  • This paper gives new conceptual descriptions of drag reduction mechanism owing to rotating wheel and moving ground condition when dealing with automotive aerodynamics. Using Computational Fluid Dynamics (CFD), flow simulation of three dimensional automobile configuration made by Vehicle Modeling Function (VMF) is performed and the influence of wheel arch, wheels, rotating wheel & moving ground condition to the automotive aerodynamic performance is analyzed. Finally, it is shown that rotating wheel & moving ground condition decreases automotive aerodynamic drag owing to the reduction of the induced drag led by the decrease of COANDA flow intensity of the rear trunk flow.

Slope Failure Index System Based on the Behavior Characteristics : SFi-system (거동 특성에 따른 사면 파괴 지수 시스템 : SFi-system)

  • 윤운상;정의진;최재원;김정환;김원영;김춘식
    • Journal of the Korean Geotechnical Society
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    • v.18 no.2
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    • pp.23-37
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    • 2002
  • Failure of the cut slope is triggered by combination of internal and extemal failure factors. Internal failure factors are related to geological and geometrical conditions of slope itself, and natural and/or artificial loadings on slope can be the external failure factors. Influences of these failure factors show different intensity according to the ground condition and are controlled by behavior characters of the slope. In this study, the soil depth ratio(SR), block size ratio(BR) and rock strength are used as the criteria to divide ground condition based on behavior characteristics. Ground condition of the slope is divided into discontinuous jointed rock mass and continuos soil-like mass, highly fractured rock mass and massive rock mass by the criteria(SR and BR). The SFi-system is a rating system to determine the slope failure index(SFi) by analyzing internal and external factors based on classification of the ground condition. The results of the SFi-system application to the real cut slopes show close relationship between the SFi value and potential or dimension of the failure. Therefore, the SFi-system can be used as a useful tool to predict and analyze the characteristic of the slope failure.

Mechanical characteristics of high-performance concrete shield segment containing ground granulated blast furnace slag and their improvement by steam curing (고성능 쉴드 세그먼트용 고로슬래그 미분말을 혼입한 콘크리트의 역학적 특성 및 증기양생 효과 분석)

  • Kim, Byoung-Kwon;Lee, Jin-Seop;Lee, Gyu-Phil;Chang, Soo-Ho;Bae, Gyu-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.13 no.3
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    • pp.233-242
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    • 2011
  • This study aims to evaluate the applicability of high-strength concrete mixed with blast furnace slag to shield segment lining in order to improve its performance and economic efficiency. Especially, it was also intended to derive the optimum replacing ratio of ground granulated blast furnace slag to ordinary cement as well as the optimum steam curing condition for shield segment concrete with the design strength of 60 MPa. From a series of experiments, the condition of 50% replacement of ordinary cement by ground granulated blast furnace slag and unit water content of 125 kg/$m^3$ was proposed as the optimum mixing condition. Comparing with standard curing conditions, it was also possible to expect approximately 110~442% strength improvement of concrete by steam curing in the same mixing condition.

Reinforcement Effect of Marine Structure Foundation by Deep Mortar Piling (심층몰탈파일에 의한 호안구조물의 기초보강 효과)

  • Chun, Byung-Sik;Yang, Hyung-Chil;Yang, Jin-Suk
    • Journal of the Korean GEO-environmental Society
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    • v.2 no.2
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    • pp.41-50
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    • 2001
  • In this study, for the stability analysis of marine embankment, the slope stability analysis and possibility of lateral movement with the marine embankment in ${\bigcirc}{\bigcirc}$harbor were carried out. In order to simulate the practical site condition, the expected maximum sea water level and maximum embankment height were assumed for these analyses. For the evaluation of soil properties, field test, laboratory test, and especially chemical composition analysis were performed for the this analysis. Based on these test results, the soil parameters were determined by applying ground improvement concept under columnar stabilized ground condition and also the effect of staged backfilling was considered under the dredged ground condition. For the optimal design, the stability analyses of embankment with changed height and unchanged height were performed under unimproved soil condition. The result showed that both cases were unstable not only with slope stability but also with lateral movement. Therefore, Deep Mortar Piling was applied for stability analysis and this result was safe. As the conclusion, the deep mortar piling method was suggested as reinforced foundation design for this site.

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Acceleration Amplification Analysis according to Changes in Laminar Shear Box Boundary Conditions (연성토조의 경계조건 변화에 따른 가속도 증폭 분석)

  • Jeong, Sugeun;Jin, Yong;Park, Kyungho;Kim, Daehyeon
    • The Journal of Engineering Geology
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    • v.32 no.1
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    • pp.143-155
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    • 2022
  • In this study, the response acceleration amplification according to different conditions was analyzed by changing the boundary condition of the soil called LSB (Laminar Shear Box), which is placed on a 1 g shaking table for earthquake simulation experiments. Experiments were carried out with different boundary conditions by fixing both sides of the LSB, and two samples were tested by installing an accelerometer at the same location. In addition, using DEEPSOIL v7 program, a one-dimensional ground response analysis was performed to compare and analyze with the free field condition. As a result, it was confirmed that the acceleration was amplified as it went from the lower layer to the upper layer, and as a result of comparing it with the ground response analysis, it was confirmed that it appeared similar to the analysis under the free field condition. As a result of the SA (Spectrum acceleration) analysis, a result similar to that of the ground response analysis was obtained, and in the case of fixing, it was confirmed that the PSA (Peak Spectral Acceleration) was further amplified.

Thermal Behavior of Energy Pile Considering Ground Thermal Conductivity and Thermal Interference Between Piles (주변 지반의 열전도도를 고려한 PHC 에너지파일의 열 거동 및 파일 간 열 간섭 현상에 대한 수치해석 연구)

  • Go, Gyu Hyun;Yoon, Seok;Park, Do Won;Lee, Seung-Rae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.6
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    • pp.2381-2391
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    • 2013
  • In general, ground's thermal properties, types of heat exchanger, operational method, thermal interference between piles can be considered as key factors which affect the thermal performance of energy pile. This study focused on the effect of these factors on the performance by a numerical model reflecting a real ground condition. Depending on the degree of saturation of ground, pile's heat transfer rate showed a maximum difference of three times, and the thermal resistance of pile made a maximum difference of 8.7%. As for the type of heat exchanger effects on thermal performance, thermal efficiency of 3U type energy pile had a higher value than those of W and U types. The periodic operation (8 hours operation, 16 hours pause) can preserve about 20% of heat efficiency compared to continuous operation, and hence it has an advantage of preventing the thermal accumulation phenomenon. Thermal interference effect in group piles may vary depending on the ground condition because the extent decreases as the ground condition varies from saturated to dry. The optimal separation distance that maintains the decreasing rate of heat efficiency less than 1% was suggested as 3.2D in U type, 3.6D in W type, and 3.7D in 3U type in a general ground condition.