• Geomechanics and Engineering
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• 제14권4호
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• pp.345-354
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• 2018

Currently, layered geogrid method (LGM) is the commonly practiced technique for reinforcement of slopes. In this paper the geogrid-box method (GBM) is introduced as a new approach for reinforcement of rock-soil slopes. To achieve the objectives of this study, a laboratory setup was designed and the slopes without reinforcements and reinforced with LGM and GBM were tested under the loading of a circular footing. The effect of vertical spacing between geogrid layers and box thickness on normalized bearing capacity and failure mechanism of slopes was investigated. A series of 3D finite element analysis were also performed using ABAQUS software to supplement the results of the model tests. The results indicated that the load-settlement behavior and the ultimate bearing capacity of footing can be significantly improved by the inclusion of reinforcing geogrid in the soil. It was found that for the slopes reinforced with GBM, the displacement contours are widely distributed in the rock-soil mass underneath the footing in greater width and depth than that in the reinforced slope with LGM, which in turn results in higher bearing capacity. It was also established that by reducing the thickness of geogrid-boxes, the distribution and depth of displacement contours increases and a longer failure surface is developed, which suggests the enhanced bearing capacity of the slope. Based on the studied designs, the ultimate bearing capacity of the GBM-reinforced slope was found to be 11.16% higher than that of the slope reinforced with LGM. The results also indicated that, reinforcement of rock-soil slopes using GBM causes an improvement in the ultimate bearing capacity as high as 24.8 times more than that of the unreinforced slope.

• ALGAE
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• 제23권4호
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• pp.327-334
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• 2008

Seaweed biomass was estimated using a nondestructive sampling method in the rocky intertidal and subtidal zone in Daejin on the mid-east coast of Korea from August 2006 to April 2008. Seasonal sampling were done at the depth of 0, 1, 5, 10 m using 50 x 50 cm quadrat. A total of 95 species, including 11 chlorophytes, 26 phaeophytes, 57 rhodophytes and one sea grass were identified. Mean biomass was comprised of 1,292 g wet wt m$^{-2}$ and the biomass values varied seasonally from 904 g to 1,945 g. Dominant species in biomass were Sargassum spp. (S. horneri, S. yezoense), Corallina pilulifera, Phyllospadix japonica, Symphyocladia latiuscula, Hizikia fusiformis, Codium arabicum and Chondrus ocellatus at Daejin. The vertical distribution of algae were characterized by Corallina pilulifera, Symphyocladia latiuscula, Sargassum spp. (S. confusum, S. yezoense), Hizikia fusiformis and Grateloupia elliptica at intertidal zone, Sargassum spp. (S. fulvellum, S. horneri, S. yezoense), Phyllospadix japonica, Codium arabicum, Undaria pinnatifida and Corallina pilulifera at 1 m depth, Sargassum spp. (S. horneri, S. micracanthum, S. yezoense), Phyllospadix japonica, Grateloupia elliptica, Gelidium amansii and Codium arabicum at 5 m depth and Phyllospadix japonica, Codium arabicum, Sargassum spp. (S. horneri, S. micracanthum, S. yezoense) and Undaria pinnatifida at 10 m depth.

• 해양환경안전학회지
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• 제22권7호
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• pp.836-845
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• 2016

본 연구에서는 하계 한국 남동해 간절곶 주변해역의 냉수대 구조와 변동을 CTD 관측과 수층별 수온 장기 연속 모니터링 자료를 이용하여 분석하였다. 냉수대의 표층수온은 냉수기 이전과 $-12^{\circ}C$의 차이를 보였으며 해저지형 효과로 간절곶에서 냉수대 세력이 가장 컸다. 남북해역 간 등온선의 시계열분포에 간절곶을 경계로 공간변화가 발생해 간절곶 주변 해저지형이 언덕(hill)역할을 하고 있음이 추정되었다. 냉수대는 해안에 평행한 풍속이 양(+)의 값일 때 출현하는 연안용승반응을 나타냈고, 수온의 감소와 상승은 풍향이 바뀐 후 하루 이내에 반응하였다. 간절곶 주변은 얕은 수심 주위에서 발생하는 와류효과가 결합하여 바람에 의한 용승효과가 강화되었다. 수온변화는 2~6일 주기의 바람변동에 민감하였으며, 수온감소는 12~36시간의 위상차를 나타냈다. 냉수대가 출현한 7월은 2~3일 주기, 8월은 3~8일 주기에서 바람-수온변화의 상관성이 컸다.

• Nuclear Engineering and Technology
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• 제38권4호
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• pp.375-382
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• 2006

Characterization tests (load vs. displacement curve) are conducted for the springs of Zirconium alloy spacer grids for an advanced LWR fuel assembly. Twofold testing is employed: strap-based and assembly-based tests. The assembly-based test satisfies the in situ boundary conditions of the spring within the grid assembly. The aim of the characterization test via the aforementioned two methods is to establish an appropriate assembly-based test method that fulfills the actual boundary conditions. A characterization test under the spacer grid assembly boundary condition is also conducted to investigate the actual behavior of the spring in the core. The stiffness of the characteristic curve is smaller than that of the strap-wised boundary condition. This phenomenon may cause the strap slit condition. A spacer grid consists of horizontal and vertical straps. The strap slit positions are differentiated from each other. They affords examination of the variation of the external load distribution in the grid spring. Localized legions of high stress and their values are analyzed, as they may be affected by the spring shape. Through a comparison of the results of the test and FE analysis, it is concluded that the present assembly-based analysis model and procedure are reasonably well conducted and can be used for spring characterization in the core. Guidelines for improving the mechanical integrity of the spring are also discussed.

• 한국광학회지
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• 제18권6호
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• pp.401-409
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• 2007

액정 디스플레이에 사용하는 직하형 Back Light Unit(BLU)의 확산판과 프리즘판의 개수를 줄이면서도 성능을 개선한 새로운 일체형 복합필름을 제안하고 이들의 광학적 성능을 시뮬레이션으로 분석하였다. 막대 프리즘의 형태와 원통 렌즈 형태를 하나로 합친 복잡한 일차원 형태의 광학프리즘을 만든 후, 이를 연속적으로 배열하여 일체형 복합필름을 구성하였다. 일체형 복합필름의 성능은 조명계 프로그램으로 확인하여 최적의 구조를 정하였다. 이러한 최적 조건하에서 한 장의 일체형 복합필름을 사용하는 10인치 크기의 BLU에서 계산한 광효율은 53.5%이고, 광휘도 균일도는 83.5%였으며, 각도별 광휘도 분포인 배광곡선은 수직으로 $90^{\circ}$이고 수평방향으로 $112.5^{\circ}$이다. 그리고 이러한 설계로 새로운 일체형 복합필름을 제작하였다.

• Journal of Plant Biology
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• 제37권3호
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• pp.309-316
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• 1994

To make regional comparisons of water status of pitch pine, the temporal changes of water status in pitch pine were investigated at different areas; urban Seoul (heavily polluted area), surburb of Seoul (lightly polluted area), and rural area (control). The effects of air pollutants, acid rain and chemical properties of soil on water deficit in pitch pine were also investiaged. Water content of needles growing at polluted areas were usually lower than that at unpolluted area. Water saturation deficit of needles growing at polluted areas were usually higher than that at unpolluted area especially in dry season. These results indicated that water in needles growing at polluted areas were usually more deficient than that at unpolluted area, and were more deficient in April than other months. At polluted areas, the older the needles were, the more quickly transpirated the water in the needle was. At unpolluted areas, however, water in old needles was not so quickly transpirated as those at polluted areas. Water potential of needles of pitch pine seedlings treated with simulated acid rain (SAR) of pH 3.5 decreased more quickly than that of needles treated with SAR of pH 5.6. Loss of water through epicuticular layer was greater in the following order: magnesium deficiency＋100 $\mu$M aluminium>100$\mu$M aluminium>magnesium deficiency>control. In addition to Mg deficiency and Al toxicity, growth decline of pitch pine widely occurring in polluated Seoul could to a large extent be due to cuticle degredation and abnormal vertical distribution of fine roots, which lead to water stress, particularly in dry seasons.

• PNF and Movement
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• 제16권1호
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• pp.67-73
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• 2018

Purpose: Smartphones, which are widely used worldwide to detect acceleration and position, have been used in the area of rehabilitation medicine in recent clinical research studies and tests. The aim of the present study was to determine the feasibility of using a smartphone application based on center of movement (COM) displacement to measure gait parameters in stroke patients in the clinical field of rehabilitation medicine. Methods: The study consisted of 30 stroke patients. The COM was measured using a smartphone application, Gait Analysis Pro, during a 6-m walk. Each patient performed three 6-m walking trials, and the smartphone application measured gait duration, gait speed, step length, cadence, and vertical and lateral displacement of the COM. The Kolmogorov-Smirnov test was conducted to determine the normality in gait parameters, and a repeated one-way analysis of variance (ANOVA) was performed to determine the consistency among the three trials. A p value of 0.05 was considered statistically significant in all the tests. Results: In all the measured parameters, the smartphone application showed a normal distribution, as shown by the results of the Kolmogorov-Smirnov test. There were no significant differences among the three repetitive walking trials. Conclusion: These results suggest that the smartphone application can be used for evaluating gait in stroke patients, as well as in healthy adults. However, prior to using the smartphone application in the clinical field, further research involving three-dimensional gait analysis is needed to enhance the confidence level of the findings.

• 국제초고층학회논문집
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• 제6권2호
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• pp.149-163
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• 2017

With the intensification of urban development in Chinese cities, mixed land use in urban centers extends vertically into 3-D and expands its scale from a single building to commercial clusters. The multi-level pedestrian system in city centers also changed its role from one of traffic isolation to spatial integration, where transit nodes, street sidewalks, squares, building entrances, atriums, and corridors are interconnected, both horizontally and vertically, into a whole spatial system, within which pedestrian flows are guided and shopping facilities are arranged. This paper uses spatial configuration analysis of space syntax to examine the impacts of spatial patterns on movement distribution and the business performance of tenant mix in the multi-level commercial system of the Nanshan Commercial Cultural District in Shenzhen, China. The key objective is to better understand the interactions between the socio-economic variables and spatial design parameters of a shopping complex. The research findings point to the importance of multiplicity between syntactic variables and other spatial variables in influencing the pedestrian flows, business performance and tenant mix in highly complex commercial systems. Particularly noteworthy is the relationship between spatial accessibility measures and the location of escalators, and the ways in which individual commercial buildings are embedded into the overall spatial system. The study suggests that this may lead to the preliminary identification of the spatial qualities of effective vertical extensions of mixed land use in a high-density urban settings.

• 한국운동역학회지
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• 제16권1호
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• pp.43-53
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• 2006

Among several movements that occurred upon a slope, golf swing is the most typical one because environmental conditions dynamically vary with many kinds of slopes. Some studies on the golf swing were performed about a weight transfer on flatland, however, there couldn't be seen any study about the weight transfer on slope elsewhere. Therefore, the purpose of this study was to provide quantified data to objectively test the coaching words and keys about the weight transfer at sidehill slope during goal impact EspeciaIly sidehill Slopes with ball above the feet. Four highschool golfer, who have average handy 5, were recruited for this study. Plantar pressure distribution and cinematographic data were collected during golf swing in the conditions of flatland, $5^{\circ}$, $10^{\circ}$ and $15^{\circ}$sidehill slope simultaneously. The two data were used to synchronize the two data later. The plantar regions under the foot were divided into 8 regions according to the directly applied pressure pattern of the subject to insole sensor. The 8 foot regions were hullux, medial forefoot, central forefoot, lateral forefoot, medial midfoot, lateral midfoot, medial heel, and lateral heel. And the plantar pressure data was also divided into four movement address, phases-backswing. downswing, and follow-through phases according to the percentage shown to the visual information of film data. Based on the investigations on public golf books and experiences of golfers, it was hypothesized by the authors in the early of this study that the steeper slopes are, the more weight loads on left foot that positions at the higher place. When observing the results of plantar pressure and vertical force curves according to the sidehill slope conditions, the hypothesis could be accepted.

• 한국운동역학회지
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• 제17권1호
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• pp.135-144
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• 2007

The purpose of this study was to identify the effect of the subtalar sling ankle taping, by measuring changes in peak plantar pressure and subtalar angle during jump landing and walking in healthy subjects with subtalar sling ankle taping applied of the ankle joint. Fifty healthy subjects(8 males and 7 female, aged 22 to 25) were randomly divided into a participated in this study. They were free of musculoskeletal injury and neurologic deficit in lower extremity. The subjects were asked to perform 5M walking and single leg jump landing by under the guidance of physical therapists. Subtalar motions were typically measured as the angle made between the posterior aspect of the calcaneous and the posterior aspect of the lower leg during walking with taping or not. This measurement were made using a video system (30Hz sampling rate, rectified 60 Hz sampling rate). At the same time, peak lateral and vertical pressure were investigated using pressure distribution platforms(MatScan system) under foot during walking and single leg jump landing with taping or not. Statistical analysis was done by paired t-test and intraclass correlation coefficient [ICC(3.1)], using software SPSS. We have recently demonstrated significantly altered patterns of subtalr joint and peak plantar pressure when applied subtalar sling ankle taping(p<.05). Inversion angle of subtalar joint significantly decreased with taping(p<.05). The result suggest that pressure patterns observed in subjects are likely to result due to significant decrease in stress on ankle joint structures during jump landing and walking. Also, the result that the subtalar sling ankle taping procedure provides greater restiction of motion associated with ankle inversion. However, this study involved asymptomatic subjects without history of ankle inversion injury, further research is needed to assess the motion restraining effect of the subtalar sling ankle taping in subjects with lateral ankle instability.