• Architectural research
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• 제3권1호
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• pp.53-60
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• 2001

The proposed building upgrading technique employs prestressing cables to function as bracing to improve the seismic performance during future events. A four-story reinforced concrete moment resisting frame damaged from an ultimate limit state earthquake is assessed and upgraded using the proposed technique. Both existing and upgraded buildings are evaluated in regard of seismic performance parameters performing static lateral load to collapse analysis and dynamic nonlinear time history analysis as well. To obtain realistic comparison of seismic performance between existing and upgraded frames, each frame is subjected to its critical ground motion that has strength demand exceeding the building strength supply. Furthermore, reliability of static lateral load to collapse analysis as a substitute to time history analysis is evaluated. The results reveal that the proposed upgrading technique improves the stiffness distribution compared to the ideal distribution that gives equal inter-story drift. As a result, the upgraded building retains more stories that contribute to energy dissipation. The overall behavior of upgraded building beyond yield is also enhanced due to the gradual change of building stiffness as the lateral load increases.

• Computers and Concrete
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• 제30권3호
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• pp.209-224
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• 2022

In this paper, the artificial neural network (ANN) is employed to predict the flexural behavior of reinforced concrete (RC) beams retrofitted with carbon fiber/epoxy composites modified by carbon nanotubes (CNTs). Multiple techniques are used to improve the accuracy of the ANN prediction, as the data represents a multivalued function. These techniques include static ANN modeling, ANN modeling with load history, and ANN modeling with double load history. The developed ANN models are used to predict the load-displacement profiles of beams retrofitted with either CFRP or CNTs modified CFRP, flexural capacity, and maximum displacement of the beams. The results demonstrate that the ANN is able to predict the flexural behavior of the retrofitted RC beams as well as the effect of each parameter including the type of the used epoxy and the presence of the CNTs.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 가을 학술발표회 논문집
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• pp.45-50
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• 1991

This research has been carried out experimently to verify the structural efficiency of the reinforced concrete columns subjected to cyclic lateral loadings in the inelastic range. Sixteen specimens have been used in the tests, the factors such as reinforcing bars, shear-span ratio, axial load level and loading history being taken differently. The load-carrying capacities and the stiffness degradation in the inelastic range by cycle lateral load application have been counted by observing the load-deformation relationship, the crack initiation and propagation and the energy dissipation phenomena.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.913-920
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• 1996

In this study, the counting method for multi-axial and multi-point load states was proposed. Using this counting method, the load spectrum is generated from the service load history which is measured for boom structure of excavator. Loading state for loading points of boom structure is described as a multi-dimensional state space. From this load spectrum, the stress spectrum was generated by FEM analysis using the superposition of the unit load. The cumulated damage at the severe damage point of In nm structure by the failure example is calculated by Palmgren-Miner's rule. As a result of this study, the fatigue life estimation using the multi-axial and multi-point load counting method is useful.

• Earthquakes and Structures
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• 제6권4호
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• pp.437-455
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• 2014

Some conventional lateral load patterns for pushover analysis, and proposing a new accurate pattern was investigated in present research. The new proposed load pattern has load distribution according weight and stiffness variation in height and mode shape of structure. The assessment of pushover application with mentioned pattern in X type braced steel frames and steel moment resisting frames, with stiffness and mass variation in height, was studied completely and the obtained results were compared with nonlinear dynamic analysis method (including time history analysis). The methods were compared from standpoints of some basic parameters such as displacement, drift and shape of lateral load pattern. It is concluded that proposed load pattern results are closer to nonlinear dynamic analysis (NDA) compared to other pushover load patterns especially in tall and medium-rise buildings having different stiffness and mass during the height.

• 한국해양공학회지
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• 제33권6호
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• pp.627-631
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• 2019

Recently, researchers in Korea and abroad actively have conducted research activities using the ARAON, a Korean icebreaking research vessel. The ARAON regularly conduct research activities in the Arctic and Antarctic waters every year. The icebreaking mode, which can be either continuous breaking or ramming, is determined by the conditions of the ice and the ice-covered waters. When the icebreaker encounters thick sea ice or an ice ridge, ramming is used. At that time, the speed of the ship generally is slower than that of continuous icebreaking. In this study, the ice load signal at the time of repetitive ramming during ARAON's 2012 Antarctic research voyage was analyzed. The time history of the ice load signal and the change in the speed of the ship used in ramming were compared with these values during continuous icebreaking.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1991년도 제2차 학술발표초록집
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• pp.62-62
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• 1991

• 대한설비공학회지:설비저널
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• 제18권5호
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• pp.437-444
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• 1989

• Asian Pacific Journal of Cancer Prevention
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• 제16권12호
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• pp.4927-4935
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• 2015

Northeastern India is a major nasopharyngeal carcinoma (NPC) high risk-area although the rest of the country has very low incidence. A case-control study of 105 NPC cases and 115 controls was conducted to identify the potential risk factors for NPC development in this region. Information was collected by interviewer about socio-demographic characteristics, cigarette smoking, alcohol consumption, dietary history, occupational history, and a family history of cancer. Epstein-Barr viral load was assayed from the blood DNA by real time PCR. Associations between GSTs genotypes, cytochrome P450 family including CYP1A1, CYP2E1 and CYP2A6 polymorphisms and susceptibility to relationship between the diseases were studied using PCR-RFLP assay. Results indicate that Epstein-Barr virus load was significantly higher in patients compared to controls (p<0.0001). Furthermore, concentration of blood EBV-DNA was significantly higher in advanced stage disease (Stage III and IV) than in early stage disease (Stage I and II) (p<0.05). Presence of CYP2A6 variants that reduced the enzyme activity was significantly less frequent in cases than controls. Smoked meat consumption, exposure to smoke, living in poorly ventilated house and alcohol consumption were associated with NPC development among the population of Northeastern India. Thus, overall our study revealed that EBV viral load and genetic polymorphism of CYP2A6 along with living practices which include smoked meat consumption, exposure to smoke, living in poorly ventilated houses and alcohol consumption are the potential risk factors of NPC in north eastern region of India. Understanding of the risk factors and their role in the etiology of NPC are helpful forpreventive measures and screening.

• 한국항해항만학회지
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• 제37권2호
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• pp.143-148
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• 2013

본 연구의 목적은 빙해역을 운항하는 선박의 쇄빙시 깨진 해빙에 의해 선수부 좌현 외판에 작용하는 국부 빙하중을 계측한 신호의 특성을 조사하는 것이다. 한국 최초의 쇄빙연구선인 아라온호를 이용하여 2010년 8월초 북극해에서 실선 시험을 수행하여 선수부에 설치된 변형률 게이지로부터 국부적인 빙하중에 의한 신호를 계측하였다. 국부적인 빙하중에 의한 구조 응답 특성을 반영한 계측 신호는 전형적인 유체 충격압에 대한 하중-시간 이력과 다소 다른 특성을 갖는 것도 있음이 파악되었다. 본 연구에서는 계측 신호에 대한 시간 이력을 분석하고, 무차원화된 특성값들로 나타내었다.