• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.153-158
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• 1995

보 및 평판의 진동에 대해서 에너지의 손실은 재료감쇠를 이용한 표면감쇠처리나 지지부에서의 감쇠처리에 의하여 증가될 수 있다. 감쇠재료를 이용한 표면감쇠처리의 예로서 보/평판 표면에 접착되는 감쇠 테이프나 코팅등은 아주 효과적임이 입증되었다. 마찬가지로 지지부 감쇠처리는 점탄성재료의 삽입에 의해서 설명될수 있다[1]. 보/평판의 감쇠에 대한 최근의 많은 연구들은 진동하고 있는 보/평판의 표면에 적용하는 감쇠 테이프 혹은 적층형태의 감쇠 처리방법에 대해서 주로 수행되었다. 일반적으로 표면감쇠처리방법은 진동감소에 아주 효과적이지만 실제 적용상에서 항상 가능한 것은 아니며, 이와 같은 경웨는 지지부 감쇠 처리방법에 의존하게 된다[2]. 감쇠특성을 갖는 점탄성재료를 실제로 적용할 때 보/평판의 유한한 길이가 점탄성재료로 지지되며 점탄성재료의 물성치와 치수에 따라서 계의 모우드 매개변수(고유진동수, 계의 손실계수 그리고 모우드형상)가 크게 달라진다. 그리고 이와 같은 계에 대해서는 지지부의 거동보다는 전체 시스템의 고유진동수와 손실계수 그리고 보 영역에서의 모우드 형상에 더 관심이 있으므로 지지부 영역을 집중매개변수(lumped parameter)로 나타내어 계를 해석할 수 있다. 일반적으로 보와 평판의 경계에서는 병진 및 회전방향의 강성 뿐만 아니라 두 강성사이에 연성효과도 동시에 발생하게 되므로 이 항을 고려하여 계를 모델링해야 한다. 본 연구에서는 우선 점탄성 재료에 의한 지지부영역의 등가 강성계수들을 구하고 경계에 강성행렬을 갖는 보의 등가시스템을 얻는다. 그리고 등가시스템의 주파수방정식으로부터 모우드 매개변수에 대한 지지부의 영향을 살펴본다. 또한 시스템이 비교적 복잡한 사각 평판의 진동에 대해서도 동강성행렬법(dynamic stiffness matrix method)을 이용하여 해석하고자 한다. 수준임이 입증되었다. 본 연구의 결과를 토대로우리나라 젊고 건강한 남성에게 적합한 무게상수는 작업자군에 대하여 25.05kg, 학생군에 대하여 20.24kg 으로 나타나 이는 미국 NIOSH 안전기준과 대체로 일치함을 발견하였다.ive structures utilized in Client/server architecture for distribution and cooperative processing of application between server and client this study presents two different data management methods under the Client/server environment; one is "Remote Data Management Method" which uses file server or database server and. the other is "Distributed Data Management Method" using distributed database management system. The result of this study leads to the conclusion that in the client/server environment although distributed application is assumed, the data could become centralized (in the case of file server or database server) or decentralized (in the case of distributed database system) and the data management method through a distributed database system where complete responsi

• Geotechnical Engineering
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• v.14 no.5
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• pp.163-172
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• 1998

To study the carrying capacity behavior of pile, dynamic pile testis and static load tests were carried out on two instrumented piles during and some time after pile driving. Cone Penetration Test( CPT) and Standard Penetration Test(SPT) were also performed at the test site before pile tests to investigate the relationship between unit skin friction of piles and cone tip resistance values and SPT N values. Total static capacity of pile reached the ultimate stage at the pile head settlement of about 0.055D (D : Pile diameter), at which skin friction of Pile already Passed the maximum value, but the end bearing was still increasing with the pile head settlement. The carrying capacity of pile increased in the form of natural logarithmic function with the time after pile driving. The increase in skin friction with time was very substantial the increase in skin friction 40 days after pile driving was 4.6 times of that determined during pile driving. The contribution of skin friction to the total capacity twas insignificant in the beginning, but became substantial 40 days after pile driving. This implies that the tested pile initially responded as an end bearing pile and later behaved as a friction pile. It was also noted that unit skin friction of pile might be ielated to cone tip resistance values(q.) and SPT N values, though the coefficient of this relationship might differ from one soil group to another and was somewhat greater than the value used in the design practice of Korea.

• Geotechnical Engineering
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• v.13 no.5
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• pp.75-88
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• 1997

In this study an iterative procedure for the analysis of drilled shafts was proposed on the basis of the load transfer mechanism. Special attention was given to the estimation of bearing capacity of drilled shafts which was compared with driven piles, and then with the results of pile load test. The load displacement at the pile head was calculated by load than sfer curves (t -z curves, q-z curves) by using Vljayvergiya, Castelli and hi -linear models. Bab ed on the analytical results, it is found that the behavior of drilled shafts is different from that of driven piles the smaller the skin friction mobilized at the pile-boil interface, the smaller the development of the bearing capacity. Hence the greater pile head movement is required to mobilize the same mainitride of bearing capacity. This trend is more noticeable in sand than in clay. It is also found that as the length-todiameter ratios increase, the dirtference of ultimate bearing capacity between drilled shafts and driven piles is becoming lass ger in sand, but it is minor in clay.

• Journal of the Korean GEO-environmental Society
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• v.4 no.2
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• pp.65-76
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• 2003

Stone column is a soil improvement method and can be applicable for loose sand or weak cohesive soil. Since the lack of sand, stone column seems one of the most adaptable approach for poor ground as a soil improvement technique. However, this method was not studied for practical application. In this paper, the bearing capacity of single stone column at the Gaduk, Ulsan and Gwangyang under the bulging and general shear failure mode were compared with those of the suggested formulas. Especially, a test result of single stone column at the Busan area by static load was compared with the bearing capacity of suggested formulas. The analysis results showed that there were not much bearing capacity differences among those suggested bearing capacity formulas. However, the bearing capacity by static load test was almost double of those with suggested formula. The result also showed that the undrained shear strength was the most important parameter for the bearing capacity estimation of stone column.

• Journal of the Korean GEO-environmental Society
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• v.10 no.5
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• pp.19-26
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• 2009

Rammed Aggregate Pier (RAP) method is intermediate foundation between deep and shallow foundation, and it has been built in world wide. RAP represents a relatively new method that has grown steadily over 19 years since Geopier of USA developed this revolutionary method in 1989. The investigation and research in domestic is not accomplished. In this paper, the examined details of different spacing of piles, bearing capacities, respectively, conclude with recommendations on how RAP can be used in future needs. This documentation further provides comparisons of the laboratory test results which were obtained from changing the spacing of piles, namely installed rammed aggregate pier. Laboratory model test was administered in a sand box. Strain control test was conducted to determine the bearing capacities of the piers; 20 mm, 30 mm and 40 mm RAP in diameter using drilling equipment to make holes were installed in sand at initial relative densities of 40%. By comparing different spacing of piles, in this experiment, piles are spaced structually span, form a ring shape, narrowing the distance of each other, to the center. the result shows that as diameter of pier is bigger in diameter, bearing capacity also dramatically increased due to raised stiffness. Also, as the space between each piers was closed, the settlement rate of soil was decreased significantly. From the test results, as the space between each piles were getting closer, it allows greater chances to have more resistance to deformation, and shows more improved stability of structures. After from the verification work which is continuous leads the accumulation of the site measuring data which is various, and bearing capacity and the settlement is a plan where the research will be advanced for optimum installed RAP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5132-5142
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• 2015

The purpose of this study was to find effect of upper extremities exercises using two different supporting surface, mobile surface and fixed surface in sitting on the function of upper extremities for the patients with stroke. The study period was between July 5, 2012 and August 1 2012. The subjects were 20 subjects who were randomly divided into two groups : (1) mobile surface group, (2) fixed surface group. The mobile surface group performed bilateral upper extremities exercise sitting on balance disc, and the fixed surface group was provided fixed surface chair. Both groups performed 30 minutes 5 times per a week for 4weeks. The Manual Functional Test(MFT) and Fugl-Meyer Motor Function Assessment(FMA) was used to measure the differences of upper extremity functions before and after interventions. The results of this study were as follows. First, Both groups, mobile surface group and fixed surface group showed the significant increase(p<.05) in upper extremity function. Second, the improvements of the hand function in mobile surface group showed significant difference comparing with the group with fixed surface. Therefore, the results of this study showed the bilateral hand exercise program on mobile surface is more effective than the fixed surface bilateral hand exercise program for the patients with stroke.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.5
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• pp.331-339
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• 2020

In this study, ways to reduce the edge pressure at the bottom plate of the caisson breakwater were considered. The water depth, freeboard, design wave height and period, and the location of the center of gravity on the super-structure of the breakwater were selected as key design variables that influence the edge pressure, and analyzed how the edge pressure changes according to the change of this key variables. The pressure distribution formulae suggested in the design standard was applied for the calculation of design wave forces. Based on the wave forces, the required effective self-weight of the super-structure and the minimum width of the caisson were determined to have a safety factor of 1.2 against sliding and overturning. From the results, it was found that the edge pressure rapidly increased as the water depth increased, and could exceed the allowable bearing capacity when it reached a certain water depth which is 20 m within the analysis conditions. It was also confirmed that the edge pressure gradually increased linearly as the freeboard increased, but decreased with the increase of the wave height and period. This edge pressure could be significantly reduced up to more than 20% by moving the center of gravity of the super-structure to the seaside, which is 5% of the caisson width. Based on the analysis results and the recently conducted research results, a method was proposed to reduce the edge pressure that can be used in the design.

• Journal of the Korean GEO-environmental Society
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• v.6 no.3
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• pp.47-54
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• 2005

In many practical cases, design methods of pile have been used mainly semi empirical bearing capacity equations. It can be done that confirmation of pile bearing capacities through using of dynamic and static tests during constructing or after constructions. If a prediction of layered point pile bearing capacity could be done through simple tests during field investigation, it could be done that more reliable design of pile than a prediction of using semi empirical equations or static formulations. This paper suggests a method to estimated point bearing capacity during in-situ investigation by using the dynamic rod model pile and verifies the point bearing capacity compare with results of static pile load tests. From test results, the unit ultimate point bearing capacities are relatively similar through a dynamic rod model pile tests and static pile load tests. The unit ultimate point bearing capacity by using N value is shown about 50 % value of measured unit ultimate point bearing capacity from field test result and the prediction of the unit ultimate point bearing capacity by using N value is shown very conservative, illogical and uneconomical pile designs.

• Proceedings of the Korean Association for Survey Research Conference
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• 2011.10a
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• pp.63-81
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• 2011

The purpose of this study is to provide the newly developing ideas to compose an appropriate question and to point out the present problems in the utilization of survey result. It is very vital for the presidential preference not only to be a political achievement of the President himself, but also to be a influential base of people-related policy and its implementation. At first, it turned out to be inappropriate to make a question for the evaluation of presidential working performance in the perspective of questionnaire planning. As the respondents were not informed of what the President did, so they were more likely not to know whether the President did well or not. Secondly, the correlation analysis has been made between the evaluation question of the presidential working performance and policy-related questions including the direct one for the presidential preference in the aspect of statistical analysis. Through this process, the evaluation of the presidential working performance is not accountable and the direct question for the presidential preference is at best explainable. In conclusion, it seems more persuasive to compare the statistical outcome of the presidential preference which has been derived of to the high rating what the respondents think comprehensively not depending on a subjective decision by mass media.

• The Journal of the Korea Contents Association
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• v.12 no.11
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• pp.225-235
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• 2012

The purpose of this study was to investigate the degrees of and relationships between self-esteem, social support, and state anxiety in community-dwelling unmarried mother raising a child. Descriptive correlational study design was used. Data were collected from 65 participants with self-report questionnaires from May to December, 2011. First, the mean of self-esteem was 3.52, social support 3.49, and state anxiety 2.47 respectively. Second, the correlation between self-esteem and social support was also statistically significant(r=.286, p=.021), the correlation between self-esteem and state anxiety was statistically significant(r=-.780, p=<.001), and the correlation between social support and state anxiety was also statistically significant(r=-.425, p=<.001). Self-esteem for unmarried mother raising a child in the study was confirmed as the primary important concept. Also, the correlation between social support and state anxiety was verified as significant. Therefore, study is needed to develop a nursing intervention program for self-esteem and social support improvement, and state anxiety decrease of unmarried mother raising a child.