• Steel and Composite Structures
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• 제16권5호
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• pp.481-489
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• 2014

The function of carbon fibre reinforced polymer (CFRP) reinforcement in increasing the ductility of reinforced concrete (RC) deep beam is important in such shear-sensitive RC member. This paper aims to investigate the effect of CFRP-strengthening on the energy absorption of RC deep beams. Six ordinary RC deep beams and six CFRP-strengthened RC deep beams with shear span to the effective depth ratio of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were tested till failure in this research. An empirical relationship was established to obtain the energy absorption of CFRP-strengthened RC deep beams. The shear span to the effective depth ratio and growth of energy absorption of CFRP-strengthened deep beam were the significant factors to establish this relationship.

• 한국주거학회논문집
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• 제21권6호
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• pp.99-108
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• 2010

This study investigated the environmental indices in environmental administration, and to presents how to develop a sustainable environmental evaluation index. The index should be used to evaluate composite plans in the environmental aspects as well as means for setting goals of basic plans for the environment and its management. Specifically, the goals of composite plans are to check environments and land use frame, and evaluate individual measures (public projects). Environment policies are required to be 'a policy creating a clean environment' from 'a policy of environment regulation'. For the organization of a basic framework of environment policies, five topics are needed to be considered, such as the clarification of the idea of environment, establishment of environment regulations, environment management plan, plan to support civilian's action, and local government's efforts for the global matters of environment. For the amenity environments, people should expand their environmental behavior based on their voluntary intentions in transformation of personal life styles, projects with less load on the environment, development of environmentally-friendly projects with consideration for their impact on the earth. This study suggests that they should put more efforts into the development and implementation of useful environmental indices which effectively analyse the regional character to protect the natural ecology and create an sustainable environment with wide coverage.

• 복합신소재구조학회 논문집
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• 제4권4호
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• pp.22-29
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• 2013

Accumulation of more than 20,000,000 vehicles since the establishment of the quality of life and economic development needs several parking lots and cause crack problem in Korea. Related structures in large cities due to the lack of parking garage attached to secure underground parking structures are actively being built, and the basement parking lot will continue to increase more stories and the trend is expected to be larger. But so far, construction of the underground parking structure is related to a number of problems, including cracks in the structure. Therefore, in this study, repair, reinforcement and a few non-economic losses in the current design criteria are presented. The review of the structure used to current design criteria is to minimize crack and maximize usability.

• 토지주택연구
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• 제8권3호
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• pp.211-221
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• 2017

This study proposed hybrid coupled shear wall in the steel plate insertion method, which is capable of reinforcing the shear strength of the entire wall without increasing wall thickness in the wall-slab apartment buildings. The proposed hybrid coupled shear wall was tested for its effectiveness, shear strength and seismic behavior in experiment. As a test result, the shear strength improvement by the proposed hybrid coupled shear was found effective. Integral-type of steel plate insertion was found more effective than separate-type steel plate insertion. In this case, if the stud enforcement method proposed in this study was used, the shear strength of hybrid coupled shear wall was recommended to calculate using the KBC2016 0709.4.1(3) method. The steel plate inserted in the proposed method was found to have no significant impact on the final fracture behavior and bending strength of hybrid coupled shear wall. The shear strength at the final destruction of the wall was merely about 1/50 of the entire design shear strength. Thus, it is deemed that the wall was over excessively designed regarding the shear force in the existing design method. This finding indicates further study on wall designing to ensure effective and economic designing based on appropriate strength estimation under the destruction mechanism.

• Journal of the Korean Wood Science and Technology
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• 제48권1호
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• pp.86-94
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• 2020

This study serves as basic research for the development of a new wood-based building finishing material that improved the weakness of inorganic materials such as gypsum board and magnesium board widely used as interior finishing materials and brought out the strength of the wood. The results of evaluating the physical and mechanical properties and the environmental effect related to hazardous substance discharge having manufactured a wood-magnesium laminated composite are as follows. The thermal conductivity and thermal resistance of WML board was improved by about 28~109 percent over magnesium board due to the low thermal conductivity of wood. The adhesive strength of WML board showed a similar result to that of plywood as it exceeds 0.7N/㎟, the adhesive standard of wood veneer which is presented by KS F 3101. Bending strength and screw holding strength were more improved by manufacturing WML board than magnesium board. The WML board manufactured in this study satisfied the criteria for emissions of hazardous substances prescribed in the Indoor Air Quality Control Act, and confirmed the possibility of development as a new wood-based composite material that can replace existing inorganic materials.

• 대한기계학회논문집A
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• 제26권10호
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• pp.1997-2007
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• 2002

Composite air spindles are appropriate for the high-speed and the high-precision machining as small hole drilling of printed circuit board (PCB) or wafer cutting for manufacturing semiconductors because of the low rotational inertia, the high damping ratio and the high fundamental natural frequency of composite shaft. The axial load and stiffness of composite air spindles fur drilling operation are determined by the thrust ben ring composed of the air supply part mounted on the housing and the rotating part mounted on the rotating shaft. At high-speed rotation, the rotating part of the thrust bearing should be designed considering the stresses induced by centrifugal force as well as the axial stiffness and the natural frequency of the rotating shaft to void the shaft from failure due to the centrifugal force and resonant vibration. In this work, the air supply part of the thrust bearing was designed considering the bending stiffness of the bearing and the applied load. The rotating part of the thrust bearing was designed through finite element analysis considering the cutting forces during manufacturing as well as the static and dynamic characteristics under both the axial and con trifugal forces during high-speed rotation.

• Steel and Composite Structures
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• 제32권1호
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• pp.37-57
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• 2019

This paper presents experimental and analytical studies to evaluate the cyclic behaviour of Circular Reinforced Concrete column Steel beam (CRCS) connections. Two 3/4-scale CRCS specimens are tested under quasi-static reversed cyclic loading. Specimens were strengthened with a tube plate (TP) and a steel doubler plate (SDP). Furthermore; nine interior beam-through type RCS connections are simulated using nonlinear three-dimensional finite element method using ABAQUS software and are verified with experimental results. The results revealed that using the TP improves the performance of the panel zone by providing better confinement to the concrete. Utilizing the TP at the panel zone may absorb and distribute stress in this region. Results demonstrate that TP can be used instead of SDP. Test records indicate that specimens with TP, with and without SDP maintained their maximum strength up to 4% drift angle, satisfying the recommendation given by AISC341-2016 for composite special moment-resisting frames.

• 한국산학기술학회논문지
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• 제11권6호
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• pp.2038-2045
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• 2010

가구당 월평균 가계소득은 그룹(지역)별, 시간별로 다양한 원인에 의해서 가게소득 결정요인이 이루어지고 있어 복잡성을 띠고 있다. 본 연구에서는 복잡성을 띠고 있는 월평균 가계소득에 관련된 제 변인들을 파악하기 위해 패널 데이터를 이용한 연구 모형을 설정하고 이를 통해 가계소득에 결정적으로 영향을 미치는 제 변인에 대하여 조사, 분석, 검증한다. 본 연구는 3그룹(전국, 6개 광역시, 서울)을 분석대상으로 하였다. 분석기간은 2005년 1월부터 2009년 9월까지의 자료를 이용하였고. 월평균 가계 소득액을 종속변수로 설정하고 물가의 대용 변수로서 소비자물가지수, 주택매매가격지수, 경기변수로서 선행종합지수, 금리 및 증권변수로서 주택담보대출 과 종합주가지수 사회현상 변수로서 고용률, 보건 의료비 지출률을 설명(독립)변수로 투입하였다. 월평균 가계소득 요인을 추정한 결과 선행(경기)종합지수와 주택담보 대출은 정(+)의 영향을 미치는 유의한 변수로 나타나고 고용률, 주택매매가격지수와 보건의료비 지출률은 음(-)의 영향을 나타내는 유의적인 변수이지만 소비자물가지수와 종합주가지수는 음(-)의 영향을 나타내는 비유의적인 변수로서 월평균가계소득에는 큰 영향을 주지는 않은 것으로 나타났다.

• 한국전자통신학회논문지
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• 제5권2호
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• pp.205-213
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• 2010

본 연구는 1986년부터 2009년까지 24년 동안 한국의 부동산정책과 부동산 관련 시계열자료를 세밀하게 분석한 후에, 주택가격에 영향을 미치는 부동산 지수 변수와 거시경제 지수 변수가 주택 가격에 미치는 영향에 대한 회귀분석을 실시하여 얼마만큼 영향이 있는지 분석하고자 한다. 분석한 결과는 다음과 같다. 첫째, 한국의 부동산 정책은 후행정책이며, 정권별 부동산 정책은 서로 일관성이 없었다. 둘째, 정산적인 국면에서 부동산 문제가 발생할 때마다 규제 강화와 경기 회복 대책만 주기적으로 반복하고 이었다. 셋째, 정책에 대한 시기와 수단은 부적절하였고, 부동산 정책 시행할 때마다 부동산 경기가 더 나빠지곤 하였다. 넷째, 24년 동안 주택 유형중 주택가격 증감량이 가장 만이 오른 주택유형은 아파트였으며 가장 인가 좋았다. 정권별 주택 가격지수 증감량은 노태우(65.0%)-김대중(42.5%)-노무현(32.8%) 순으로 나타났다. 다섯째, 회귀분석을 실시한 결과 : 주택가격에 가장 많은 영향을 미치는 독립변수는 건설기 성액-1인당 국민소득-주택 전세가 지수-동행종합지수-후행종합지수-청약통자 가입자-선형종합지수 순으로 나타났다.

• Journal of Preventive Medicine and Public Health
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• 제42권6호
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• pp.392-402
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• 2009

Objectives : The aims of this paper were to develop the composite deprivation index (CDI) for the sub-district (Eup-Myen-Dong) levels based on the theory of social exclusion and to explore the relationship between the CDI and the standardized mortality ratio (SMR). Methods : The paper calculated the age adjusted SMR and we included five dimensions of social exclusion for CDI; unemployment, poverty, housing, labor and social network. The proxy variables of the five dimensions were the proportion of unemployed males, the percent of recipients receiving National Basic Livelihood Security Act benefits, the proportion of households under the minimum housing standard, the proportion of people with a low social class and the proportion of single-parent household. All the variables were standardized using geometric transformation and then we summed up them for a single index. The paper utilized the 2004-2006 National Death Registry data, the 2003-2006 national residents' registration data, the 2005 Population Census data and the 2005-2006 means-tested benefit recipients' data. Results : The figures were 115.6, 105.8 and 105.1 for the CDI of metropolitan areas (big cities), middle size cities and rural areas, respectively. The distributional variation of the CDI was the highest in metropolitan areas (8.9 - 353.7) and the lowest was in the rural areas (26.8 - 209.7). The extent and relative differences of deprivation increased with urbanization. Compared to the Townsend and Carstairs index, the CDI better represented the characteristics of rural deprivation. The correlation with the SMR was statistically significant and the direction of the CDI effects on the SMR was in accordance with that of the previous studies. Conclusions : The study findings indicated mortality inequalities due to the difference in the CDI. Despite the attempt to improve deprivation measures, further research is warranted for the consensus development of a deprivation index.