• 한국지진공학회논문집
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• 제8권1호
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• pp.1-15
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• 2004

고층의 강 모멘트저항골조에 대한 지진 응답을 살펴보기 위해서 동적해석을 실시하였다. 구조물은 세가지의 다른 설계절차로 의도적으로 설계하였고 그 세가지의 개념은 강도 지배설계, 강기둥-약보 지배설계, 횡변위 지배설계이다. 그렇게 설계한 구조물이 각각 질량비정형이 존재하도록 하여 횡변위, 소성한지, 이력에너지 입력 및 요구응력에 대해서 토론하였다. 미래에 설계에의 응용을 위해서 최대 지반가속도로 표현한 두 등급의 지진 하중을 이용해서 이력에너지 입력요구 곡선을 제시하였다.

• 한국소음진동공학회논문집
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• 제20권10호
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• pp.953-959
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• 2010

This paper deals with the process to identify the exciting forces generated from a rotary compressor. The equation of motion of a rigid compressor supported by several mounts was derived with 6 degree of freedom. The mass moment of inertia of compressor and the stiffness of rubber mounts were also identified by experiments. The exciting force at the center of mass of the compressor were estimated from the acceleration data measured at compressor shell. The piping system connected to the compressor was modeled. The acceleration of a pipe was predicted numerically by using the predicted exciting force. The numerical results showed good agreement with experimental results, which validated the identified exciting force.

• 한국해양공학회지
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• 제28권6호
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• pp.546-551
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• 2014

This paper addresses a feedback linearization control problem for the nonlinear dynamics of an underwater glider system. We consider the buoyancy and moment as control inputs, which come from the mass variation and elevator control, respectively. Moment-to-force coupling increases the nonlinearities, which make the controller design difficult. By using a feedback linearization technique, we convert the nonlinear underwater glider to an equivalent linear model and design a linear controller. The controller for the equivalent converted linear system is designed using sufficient conditions in terms of linear matrix inequalities. Then, the control input of the nonlinear model of an underwater glider is formulated from the linear control input. An experimental examination is implemented to verify the effectiveness of the proposed technique.

• Asian Journal for Public Opinion Research
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• 제2권2호
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• pp.121-139
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• 2015

"Living in the present moment," a Buddhist concept, was applied in this research. This concept urges the patients to cling neither to the past nor the future as well as being mindful of their body, feelings, mind, and mental qualities. The purpose of the study was to develop a "living in the present moment" model and to evaluate the power of "living in the present moment" in terms of physical and mental results. The study used non-participatory action research with quasi-experimental research design that included 3 camps composed of 6 main activities. The percentages, SD, and paired t-test statistics were used to analyze and compare 17 purposively selected diabetic patients from Pak Thong Chai Hospital before and after they attended the 3 camps. The patients improved significantly in terms of waistline, body weight, body mass index (BMI) and blood pressure (SBP and DBP). The mean of fasting plasma glucose (FPG) level was also changed considerably. The results revealed that the treatment helped the patients to gain self-awareness and self-realization (Yonisomanasikara), as well as knowledge and increased support from friends (Kalyanamitta). They also let go of their attachment to their physical and mental oppressions. This helped the patients to relieve their daily pain, fatigue, insomnia, and diabetes-related complications. About 75% of all patients were able to achieve lifestyle modifications. Therefore, implementation of the model should be expanded and utilized in other diabetic centers. The model might also be expanded to pre-diabetes.

• Composites Research
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• 제22권3호
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• pp.66-73
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• 2009

적층 두께, 면밀도, 질량관성모우멘트는 소재의 구조-역학적 특성을 나타내는 중요한 인자들이다. 본 연구에서는 이와 같은 인자들이 다층-복합재료구조의 내충격 성능에 미치는 영향을 고찰하기 위해 높은 충격자 속도 하에서 탄자한계속도기 최대가 되는 재료-구조 최적화를 수행하였다. 세라믹복합재료, 고무, 알루미늄 그리고 알루미늄 폼으로 구성된 다층-복합재료구조의 최적화를 위해 Florence 모델과 Awerbuch-Bonder 모델을 연계한 통합 모델을 개발하였으며, 구속 조건으로써 적층 두께, 면밀도, 질량관성모우멘트를 함께 사용하였다. 결과에서 알 수 있듯이, 제안된 통합 모델을 통해 계산된 탄자한계속도는 유한표소해석에서의 탄자한계속도와 거의 유사함을 확인하였다. 통합 모델을 바탕으로 재료-구조 최적화를 통해 설정된 다층구조는 최적화를 수행하지 않은 다층구조에 비해 약 10.8%의 탄자한계속도 및 26.7%의 충격흡수에너지 향상이 나타남을 알 수 있다.

• 한국농공학회지
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• 제42권1호
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• pp.105-112
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• 2000

This paper deals with the free vibrations of columns immersed in fluid. The column model is based on the classical Bernoulli-euler theory which neblects the effects of rotatory inerital and shear deformation. The eccentricity and rotatory inertial of the concentrated mass at the top are taken into accuont. In the governing equation for the free vibration of column, thedensity of immersed part was midified to account for theadded fluid mass. The govering differential equations are solved numerically using the corresponding boundary conditions. The lowest four natural frequencies and corresponding mode shapes are calculated over a range of non-dimensional system parameters ; the mas density ration of fluid to column, the ratio of fluid depth to span length, the ratio of tip mass to total column mass, the dimensionless mass moment of inertia, and the eccentricity.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.697-702
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• 2006

This paper deals with the free vibrations of immersed columns with soft base. The support condition of the column is represented by using a translational spring and a rotational spring. The eccentricity and rotatory inertia of the concentrated mass at the top are taken into account. In the governing equation for the free vibration of column, the density of immersed part was modified to account for the added fluid mass. The governing differential equations are solved numerically using the corresponding boundary conditions. Numerical results are presented to show the effects on the natural frequencies of non-dimensional system parameters: the mass density ratio of fluid to column, the ratio of fluid depth to span length, the ratio of tip mass to total column mass, the dimensionless mass moment of inertia, the eccentricity, the translation spring parameter, and the rotational spring parameter.

• 한국소음진동공학회논문집
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• 제20권4호
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• pp.405-413
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• 2010

The vibration characteristics of fully and partially embedded piles with flexibly supported end carrying an eccentric tip mass are investigated. The pile model is based on the Bernoulli-Euler theory and the soil is idealized as a Winkler model for mathematical simplicity. The governing differential equations for the free vibrations of such members are solved numerically using the corresponding boundary conditions. The lowest three natural frequencies and corresponding mode shapes are calculated over a wide range of non-dimensional system parameters: the rotational spring parameter, the relative stiffness, the embedded ratio, the mass ratio, the dimensionless mass moment of inertia, and the tip mass eccentricity.

• 한국지구과학회지
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• 제41권1호
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• pp.1-18
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• 2020

본 논문은 기상 모델의 미세구름물리 모수화 과정 내의 눈송이의 질량-크기 관계가 지표 강수 모의에 미치는 영향에 대해 연구에 관한 것이다. WDM6와 WSM6 미세구름물리 모수화 방안이 연구를 위해 사용되었다. 실제 관측된 자료를 바탕으로 산출된 Thompson의 눈송이의 질량-크기 관계를 도입하여 WDM6와 WSM6 내의 눈송이의 질량-크기 관계식을 대체하였다. 이상적인 스콜선과 한반도 겨울철 강수 사례에 대해 수정된 WDM6와 WSM6를 사용하여 민감도 실험을 실시하였다. 결과적으로, 대기 하층에서는 싸락눈과 빗방울의 혼합비가 증가하였고 눈송이의 혼합비는 감소하였다. 이러한 혼합비와 지표 강수의 변화는 빗방울과 눈송이의 충돌 및 병합 과정과 싸락눈의 융해 과정에 기인한 것으로 분석되었다.

• Earthquakes and Structures
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• 제7권4호
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• pp.587-607
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• 2014

Progressive collapse, which is referred to as the collapse of the entire building under local damages, is a common failure mode happened by earthquakes. The collapse process highly depends on the whole structural system. Since, asymmetry of the building plan leads to the local damage concentration; it may intensify the progressive collapse mechanism of asymmetric buildings. In this research the progressive collapse of regular and irregular 6-story RC ordinary moment resisting frame buildings are studied in the presence of the earthquake loads. Collapse process and collapse propagation are investigated using nonlinear time history analyses (NLTHA) in buildings with 5%, 15% and 25% mass asymmetry with respect to the number of collapsed hinges and story drifts criteria. Results show that increasing the value of mass eccentricity makes the asymmetric buildings become unstable earlier and in the early stages with lower number of the collapsed hinges. So, with increasing the mass eccentricity in building, instability and collapse of the entire building occurs earlier, with lower potential of the progressive collapse. It is also demonstrated that with increasing the mass asymmetry the decreasing trend of the number of collapsed beam and column hinges is approximately similar to the decreasing trend in the average story drifts of the mass centers and stiff edges. So, as an alternative to a much difficult-to-calculate local response parameter of the number of collapsed hinges, the story drift, as a global response parameter, measures the potential of progressive collapse more easily.