• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.175-181
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• 1987

Plugging effect of open-ended pipe piles is known to have a close relationship with the ratio of an embedment depth to a pile diameter, i.e., the relative embedment ratio. To evaluate this relationship in the concrete, load tests are performed on the open and the close ended model piles varying the relative embedment ratio as well as the relative density of the model test ground. Cross-shaped hollow plates are attached at the open pile ends to reduce the effective pile diameters, on which load tests are also performed. As a result, it is confirmed that higher plugging effect may be obtained in the denser ground at lower relative embedment. However, 100% plugging effect can be obtained at the relative embedment ratio of 25 or bigger regardless of the density of the ground. Increment of the plugging effect by introducing the cross-shaped attachment can hardly be achieved.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.270-270
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• 2004

이 연구는 Ⅰ) 혈관 폐색에 의한 인지 및 기억장애 동물모델에서 뇌졸중 치료제로써 인간배아줄기 세포의 신경세포 보호효과 및 작용기간을 밝히며, Ⅱ) 행동 약리학적 연구를 통해 기억력증진에 미치는 효과에 대해 밝히고 혈관 폐색에 의한 동물모델에서의 기억기능 증진 및 세포효과를 검증하고자 실시하였다. 중대 뇌동맥 폐색에 의한 쥐의 동물모델은 Sprague Dawley계 흰 쥐(260∼300 g)의 국소 중대뇌동맥을 일시적으로 폐색시켜 만들었다. 본 연구(미국 국립보건원에 등록된 MB03세포)에 사용된 인간배아줄기세포는 3×10⁴ cells/㎠ 밀도의 배양접시 내에서 4일 동안 embryoid bodies(EBs)의 형성을 위해 집합체를 이루도록 유도하였다. (중략)

• Geotechnical Engineering
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• v.5 no.4
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• pp.27-36
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• 1989

Load tests are executed on instrumented model piles to evaluate the magnitudes of soil plugging resistances mobilized at open-end pile tips. The plugging resistances are calculated by some existing methods, which are compared with observation. A couple of the methods are found to give good results. A new computational method to predict the plugging resistance is proposed in this paper, which also gives fairly close prodiction to the measurement, and is much simpler than the other computational methods.

• Journal of the Korean Geotechnical Society
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• v.33 no.12
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• pp.21-33
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• 2017

This paper presents the analysis of plugging effect especially when the large diameter steel pipe pile was installed by considering driveability (BPM, blow per meter). The Coupled Eulerian-Lagrangian (CEL) technique was used to simulate the driving of open-ended piles into soil. To consider the driveability, the applied driving energy for each pile was obtained from the analysis results by using the wave equation. The parametric studies were performed for different pile diameters, penetration depths of pile, soil elastic modulus and BPM. It was found that the SPI is almost constant with increasing both the pile diameter and the required driving energy. It is also found that the plugging effect increases with increasing the pile length, resulting in the increase of lateral earth pressure. Based on this study the apparent magnitude and distribution of the lateral earth pressure is proposed for inside portion mobilizing soil plug.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.723-730
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• 2006

Recently, The flexible moving block system in train operation has been introduced to the worldwide rail transportation markets. This paper is a comparative study of the conventional fixed block systems effects and the flexible moving block system on train operating time saving. Based on the literature review, the new algorithm is developed. It is to calculate the optimum headway time of the train. The proposed algorithm can overcome some of the existing algorithm problems, such as the limits of the data and unaware of the rail characteristic. The total travel time saving effect has been analyzed by applying the skip stop scheduling system to the each block system. The results of this study indicated that the total travel time is approximately 40% decreased and the schedule velocity is approximately 24% improved when the moving block system is applied. The results of this study could be used as a theoretical basis for the selection of rail signal system in Seoul's subway number 2 line.

• Journal of the Korean Geotechnical Society
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• v.32 no.5
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• pp.27-36
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• 2016

This paper presents the investigation of the major influence factors on the degree of soil plugging for open-ended piles based on the Coupled Eulerian-Lagrangian (CEL) numerical technique. The main objective of this study was to investigate the effect of soil plugging on the response of piles in various conditions. Through comparison of the results of field load tests, the CEL methodology was found to be in good agreement with the general trend observed by in situ measurement. Additionally, the parametric studies were performed by controlling the soil conditions, soil elastic moduli, end-bearing conditions and multi layers. It was found that the degree of soil plugging for sand layers was greater than that of clay layers. Also, the degree of soil plugging increased with an increase in both the soil stiffness and length of pile embedded in the bearing layer.

• The KIPS Transactions:PartB
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• v.13B no.7 s.110
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• pp.663-670
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• 2006

For virtual target to be displaying on real image realistically, it is essential to determine the location of the virtual object together with producing the occlusions area after registering two world. In this paper, we propose the new method to solve occlusions which happens during virtual target moves according to the simulated route on real image. For this purpose, we first construct three dimensional virtual world by DEM of experimental area and register CCD camera image on it by visual clues. Next, we also propose a method to solve the occlusion using snake and picking algorithm which can extract the three dimensional information of the position happening occlusion in the image and can use it when target moves that area. In the experiment, we proved the effectiveness of the proposed method in the environment which a partial occlusions happens.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.99-110
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• 2001

Open-ended pipe piles are often used for the foundations of both land and offshore structures because of their relatively low driving resistance. In this study, load tests were performed on model pipe piles installed in calibration chamber samples in order to investigate the effects of pile installation method on soil plugging and bearing capacity. Results of the test program showed that the incremental filling ratio (IFR), which is used to indicate the degree of soil plugging in open-ended piles, decreased (i) with increasing hammer weight for the same driving energy and (ii) with increasing hammer weight at the same fall height. The base and shaft resistance of the piles were observed to increase (i) with increasing hammer weight for the same driving energy and (ii) with increasing hammer weight at the given same fa11 height. The jacked pile was found to be have higher bearing capacity than an identical driven pile under similar conditions, mostly due to the more effective development of a soil plug in jacking than in driving.

• Journal of Acupuncture Research
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• v.27 no.3
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• pp.127-135
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• 2010

목적 : 이 연구는 알레르기 비염 또는 비부비동염으로 인한 비폐색증에 대한 침치료의 효과를 입증하고, 신혈인 심의혈의 임상적 효과를 알아보고자 시도하였다. 방법 : 2009년 9월 22일부터 11월 3일까지 2회 이상 경희의료원 동서비염클리닉에 내원하여 침 치료를 받은 비염환자를 대상으로, 무작위배정방법에 따라 실험군 또는 대조군으로 배정하였다. 실험군은 routine 혈위인 신회 상성 신정 양두유 양찬죽 양지창에 심의혈을 추가하였고, 대조군은 routine 혈위에 양영향을 추가하였다. 유침 시간은 각 군에서 15분간으로 하였다. 유효성 평가 도구로는 SNOT-20를 사용하여 비염의 전반적 증상 점수 변화를 측정하였고, VAS를 사용 하여 비폐색 완화 효과의 정도를 측정하였다. 평가시기는 치료 전후로 하였고, 통계분석은 치료 전후 SNOT-20 차이의 경우 Wilcoxon Signed Ranks Test로, VAS 비교는 Mann-Whitney Test를 이용하여 검정하였다.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.13-17
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• 2009

고해상도 위성영상의 분류 기술은 최근 가장 활발히 연구되고 있는 분야 중 하나로 텍스쳐(texture), NDVI, PCA 영상 등 다양한 전처리 정보들을 추출하고 이를 멀티스펙트럴 밴드와 조합하여 분류 정확도를 높이는 기술을 개발하는 연구들이 주를 이루고 있다. 고해상도 위성영상에서 건물의 그림자와 옆벽면의 폐색 지역은 개체 추출 및 분류를 방해하는 주된 요인이 되며, 다양한 형태와 분광특성을 갖는 개개의 건물은 자동 분류 과정을 통해 제대로 식별되지 않는다는 한계를 갖는다. 이에 본 연구에서는 KOMPSAT-2 단영상으로부터 효율적으로 건물 정보 및 토지피복을 분류하기 위하여, 추출된 건물 정보를 바탕으로 건물의 그림자와 폐색지역을 보정한 후 비건물 지역에 대한 분류를 수행하여 분류 정확도를 높이고자 하였다. 우선 삼각벡터구조 기반의 반자동 인터페이스를 이용하여 건물의 3차원 모델 및 그림자 영역을 추출하고 이로부터 추출된 그림자 영역을 효과적으로 보정하기 위해 반복 선형회귀 연산을 이용한 그림자 보정을 수행한 후 inpainting 기법을 건물 폐색영역 복원에 적용하여 영상의 품질을 향상시켰다. 이러한 과정을 통해 도심 지역의 영상 분석에 있어 가장 큰 오차를 일으키는 인공물의 그림자와 폐색에 의한 오차를 최소화한 후 분류에 적용하여 이를 보정 전 영상을 이용한 분류 결과와 비교하였다.