• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.264-267
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• 2010

This research focuses on the development of numerical code to deal with compressible two phase flow around three dimensional objects combined with cavitation model suggested by Weishyy et al. with k-e turbulent model. The cryogenic cavitation is carried out by considering the thermodynamic effect on physical properties of cryogenic fluids in physical point of view and implementing the temperature sensitivity in the energy equation of the government equations in numerical point of view, respectively. The formulation has been extensively validated for both liquid nitrogen and liquid hydrogen by simulating the experiments of Hord on hydrofoils. Then, simulations of cavitating turbopump inducers at their design flow rate are presented. Results over a broad range of Nss numbers extending from single-phase flow conditions through the critical head break down point are discussed. In particular, thermal depression effects arising from cavitation in cryogenic fluids are identified and their impact on the suction performance of the inducer quantified.

• Structural Engineering and Mechanics
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• v.5 no.6
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• pp.767-774
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• 1997

In this paper, three dimensional static behaviors of the self-anchored and partially earth-anchored cable-stayed bridges, with a span of 1400 meters, under wind loading are studied by using a 3D geometrical nonlinear analysis. In this analysis, the bridges both after completion and under construction are dealt with. The wind resistant characteristics of the both cable-stayed systems are made clear. In particular, the characteristics of the partially earth-anchored cable systems, which is expected to be a promising solution for extending the span of the cable-stayed systems further, is presented.

• Solar Energy
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• v.19 no.1
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• pp.47-57
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• 1999

A building and the solar are related to the privilege of solar benefit. To make step, it is required to build up an object, chase the position of object and the solar, find the shadow occurrence. On the subject of direct illuminance, an intensive emission of irradiation is proposed to directly project to the benefit area. Simultaneously on the indirect illuminance, the integration of a finite element incident to the benefit area can be multiplied by the hemisphere luminance. A caution should be paid to eliminate the occupation area of the object around on the hemispherical sky, which can help run more accurate prediction.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.6
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• pp.138-145
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• 2007

Among various rapid prototyping processes, stereo-lithography process which can manufacture transparent prototype is known to be the greatest in the form & dimensional accuracy and surface roughness. In this paper, bench mark tests of 4 stereo-lithography-type rapid prototyping apparatus were carried out using transparent materials. The test includes measurement of mechanical properties, form accuracy, building speed and manufacturing cost. It was observed that ViperPRO of 3D systems is advantageous in the mechanical properties and building speed, RM600011 of CMET in sub-milli scale form accuracy and manufacturing cost, and relatively economical Eden500V of Objet is great in tensile strength at room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.557-560
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• 2000

Combination of SDB(Si-wafer Direct Bonding) and electrochemical etch-stop in TMAH anisotropic etchant can be used to create a variety of MEMS(Micro Electro Mechanical System). Especially, fabrication of SDB SOI structures using electrochemical etch-stop is accurate method to fabrication of 3D(three-dimensional) microstructures. This paper describes on the fabrication of SDB SOI structures with sealed cavity for MEMS applications and thickness control of active layer on the SDB SOI structure by electrochemical etch-stop. The flatness of fabricated SDB SOI structure is very uniform and can be improved by addition of TMAH to IPA and pyrazine.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.105-108
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• 2003

The local motion at the top of an A-frame fixed on a research vessel for deep sea ROV floating in irregular waves is studied in the time-domain. The motion is analyzed in the time-domain using the convolution integral of the radiation forces. The memory effect functions and infinite frequency added masses are obtained from the solution of the three dimensional improved Green integral equation in the frequency domain by making use of the Fourier transformation.

• Advances in biomechanics and applications
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• v.1 no.2
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• pp.111-126
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• 2014

The microarchitecture of trabecular bone plays a significant role in mechanical strength due to its load-bearing capability. However, the complexity of trabecular microarchitecture hinders the evaluation of its morphological characteristics. We therefore propose a new classification method based on static multiscale theory and dynamic finite element method (FEM) analysis to visualize a three-dimensional (3D) trabecular network for investigating the influence of trabecular microarchitecture on load-bearing capability. This method is applied to human vertebral trabecular bone images obtained by micro-computed tomography (micro-CT) through which primary trabecular bone is successfully visualized and extracted from a highly complicated microarchitecture. The morphological features were then analyzed by viewing the percolation of load pathways in the primary trabecular bone by using the stress wave propagation method analyzed under impact loading. We demonstrate that the present method is effective for describing the morphology of trabecular bone and has the potential for morphometric measurement applications.

• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2630-2641
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• 1999

Most of the previous game development has proceeded in the approaches of the temporal-oriented synchronization because of producing game objects by using general authoring tools, and ad hoc or trial and error methods has been devised for representation of spatial concept. This paper is a study on the unification notation for spatio-temporal synchronization to conquest this fault. First of all, we classify game space as temporal object, spatial object, absolute/relative spatio-temporal space. The spatio-temporal relationships are divided into temporal extent, temporal location, spatial extent, and spatial location. In the paper the temporal and spatial relationships of game scene are defined to represent the synchronization, and we propose new unification notation by temporal and spatial concept to represent two concepts putting emphasis on space. Their relationships are presented on 3D by creating time axis related with time in scene unit of the two dimensional plane in the pivot on space. The usability of this representation method are shown by applying examples of game scenario.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3089-3091
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• 1999

To control IWR-III Biped Waking Robot, those complex modules are necessary that concurrent control multi-axes servo motors, PID & Feedforward gain tuning, initial value calibration, display current status of system, user interface for emergency safety and three-dimensional rendering graphic visualization. It is developed for various-type gait $data^{[1]}$ and for control modes (i.e open/closed loop and pulse/velocity/torque control) that Integrated Control Enviroment with GUI( Graphic User Interface) consist of time-buffered control part using MMC (Multi-Motion Controller) and 3D simulation part using DirectX graphic library.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.271-274
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• 1996

Shell rendering technique, which is the combined technique of surface rendering and volume rendering, was realized on workstation. By applying it to colon data acquired by CT, its validity was shown. In addition perspective projection coordinate was used for rendering the internal surface of organ and its reality was shown to be improved. This result can be use as the essential technique of virtual endoscope which is the recent hot topic in three dimensional medical imaging.