• 한국도로학회:학술대회논문집
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• 2005.11a
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• pp.215-226
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• 2005

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1999.04a
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• pp.31-31
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• 1999

• Journal of Internet Computing and Services
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• v.15 no.1
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• pp.171-178
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• 2014

This paper presents dynamic modelling of a virtual object in augmented reality environments when external forces are applied to the object in real-time fashion. In order to simulate a natural behavior of the object we employ the theory of Newtonian physics to construct motion equation of the object according to the varying external forces applied to the AR object. In dynamic modelling process, the physical interaction is taken placed between the augmented object and the physical object such as a haptic input device and the external forces are transferred to the object. The intrinsic properties of the augmented object are either rigid or elastically deformable (non-rigid) model. In case of the rigid object, the dynamic motion of the object is simulated when the augmented object is collided with by the haptic stick by considering linear momentum or angular momentum. In the case of the non-rigid object, the physics-based simulation approach is adopted since the elastically deformable models respond in a natural way to the external or internal forces and constraints. Depending on the characteristics of force caused by a user through a haptic interface and model's intrinsic properties, the virtual elastic object in AR is deformed naturally. In the simulation, we exploit standard mass-spring damper differential equation so called Newton's second law of motion to model deformable objects. From the experiments, we can successfully visualize the behavior of a virtual objects in AR based on the theorem of physics when the haptic device interact with the rigid or non-rigid virtual object.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.1
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• pp.71-80
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• 1990

The fracture characteristics of concrete under various rates of loading are investigated. The static and dynamic fracture energies of concrete are determined and the size-dependency of fracture energy is clarified from the present study. To this end, a series of experiments were conducted. The maximum failure loads, fracture energies and nominal failure stresses were calculated from those test results. It is found that the fracture energies are increased with the increase of loading rate. The fracture energy values were also greatly influenced with the size of the specimen. The size-dependent prediction eguations for the static and dynamic fracture energies of concrete are proposed in the present study. The present paper provides useful data for the dynamic fracture analysis of concrete structures.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.225-234
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• 2008

This study was carried out to select proper loading speed for deformation strength ($S_D$) of asphalt mixtures. Kim test using loading head of diameter(40mm) with radius(10mm) was conducted to measure $S_D$ in different loading speed (10mm/min, 30mm/min, 50mm/min, 70mm/min) and wheel tracking test was also conducted. The regression analyses between the So values and WT results were carried out by loading speeds. Higher $S_D$ was observed as increasing loading speed. This means that loading speed is a high influencing factor on $S_D$. The loading speed of 30mm/min was found as an optimum for better correlation with WT results than any other speeds from the regression analysis between $S_D$ and wheel tracking test results. $S_D$ value measured at other loading speed than 30mm/min has to apply the conversion coefficients.

• Explosives and Blasting
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• v.38 no.3
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• pp.30-43
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• 2020

Rock dynamics is a relatively new discipline to study the mechanical behaviors of rock materials (or rock masses) under dynamic loading conditions. Many rock mechanics and rock engineering issues are concerned with the dynamic phenomena such as mining development, civil engineering, earthquake, military science, and various disasters. The significance of rock dynamic researches has been increased in these days. This paper introduces conventional experimental techniques for rock dynamic experimental methods and the particular characteristics of rock dynamic behaviors with several remarkable recent studies.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.538-540
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• 2004

Proxy를 이용한 동적 동영상 어댑테이션[1]은 이동 단말기나 현재 네트워크 상태의 특성을 고려해 동적으로 동영상을 변형할 수 있다는 장점이 있다. 하지만 기존에 제안된 동영상 어댑테이션 방법들은 품질 측정을 위해 반복적인 디코딩, 인코딩을 해야 하기 때문에 적절한 형태의 동영상을 생성하는데 많은 시간이 걸려서 지연시간이 최우선적으로 고려되는 실제 상황에서는 이용하기가 힘들다. 본 논문에서는 반복적인 디코딩, 인코딩 작업 없이 어댑테이션된 동영상을 생성하는 동적 동영상 어댑테이션 방법을 제안한다. 인코딩된 동영상의 파일의 크기와 품질에 초점을 맞추어 비디오 코덱의 특성을 분석하고, 그 결과를 테이블로 만들어 Proxy에 저장해둔다. 이동 단말기가 동영상을 요청하면, Proxy에서는 해당 코덱의 분석 결과 테이블을 참조하여 가능한 한 최고의 품질로 디코딩 및 인코딩을 하여 어댑테이션된 동영상을 전송하게 된다.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.6
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• pp.1-10
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• 2001

In this study, the horizontal loading tests of 10ton and 200ton capacity of LRB(lead-rubber bearing) were performed for the evaluation of the dynamic properties of the LRB. It is noted from the test results that dynamic properties of the LRB are dependent on the loading frequency, vertical load and shear strain. A Slender bearing subjected to large deformation will tend to develop plastic hinges in the end regions of the lead plug which will cause the failure of the lead plug. It is recommended that the appropriate mechanical properties of LRB considering the level of structural response and input ground motion should be used in the design of base isolated structures.

• Journal of the Korean Geophysical Society
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• v.6 no.4
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• pp.277-294
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• 2003

Structures show the phenomena of deformation and lowering of function with time-lapse by artificial environments and changes of geotechnical conditions or accumulation of initial deformation elements. This study aims the structural assessment of cultural property, Chum-Sung-Dae, located in Kyeongjucity, Korea. It was built about 1,300 years ago, and has undergone deformation and ground-subsidence with time-lapse. Non-destructive evaluation techniques were applied to the Chum-Sung-Dae, to protect it from survey. Because of this reason, 3D precise laser scanning surveying system was applied to measure the exact size of Chum-Sung-Dae, displacement and declining angles. Geophysical exploration also was applied to study the subsurface distribution of geotechnical parameters or physical properties. Natural frequencies were measured from real and model of Chum-Sung-Dae to study the dynamic characteristics of vibration and/or earthquake load and stiffness of structures.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1313-1318
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• 2000

총고형분 함량$(TS:\;50{\sim}57%)$을 달리하여 숙성시킨 고추장의 유동특성, 정적 및 동적점탄특성을 관찰하였다. 고추장의 TS가 증가함에 따라서 점조도 지수(K)와 겉보기 점도$({\eta}_{a.5})$는 증가하였으며 유동성 지수(n)는 1보다 훨씬 낮은 0.24-0.31의 범위를 나타내어 고추장은 shear-thinning 성질을 보여주었다. 고추장의 항복응력 측정에서는 고추장의 TS가 증가함에 따라 Casson 항복응력$({\sigma}_{oc})$은 증가하는 경향을 나타내었으며, 또한 고추장의 액상 매개체인 serum 점도$({\eta}_{se})$는 고추장의 TS와 매우 좋은 상관관계$(R^2=0.97)$를 나타내었다. 고추장의 동적점탄성 실험에서는 주파수$({\omega})$가 증가함에 따라 저장탄성률(G#)와 손실탄성률(G@)은 증가하였으며 양(+) 기울기로 G#수치가 G@수치보다 높게 나타났다. 이는 고추장이 약한 겔과 같은 구조적 특성을 갖고 있으며 또한 shear-thinning 거동을 가지고 있음을 나타낸다. 정적점탄성 실험에서 고추장의 총고형분 함량에 따라서 순간탄성 변형$(J_0)$과 지연탄성변형$(J_1)$은 총고형분 함량이 증가함에 따라서 감소하였으며 점도$({\eta}_N)$와 지연시간 $({\tau}_1)$은 증가하였다. 따라서 고추장은 농도가 증가함에 따라 보다 탄력적이며 안정된 구조를 형성하고 있음을 알 수 있었다.