• Structural Engineering and Mechanics
• /
• 제33권1호
• /
• pp.31-46
• /
• 2009

An anisotropic damage mechanics approach is introduced which models the static and dynamic behavior of mass concrete in 3D space. The introduced numerical approach is able to model non-uniform cracking within the cracked element due to cracking in Gaussian points of elements. The validity of the proposed model is considered using available experimental and theoretical results under the static and dynamic loads. No instability and stress locking is observed in the conducted analyses. The Morrow Point dam is analyzed including dam-reservoir interaction effects to consider the nonlinear seismic behavior of the dam. It is found that the resulting crack profiles are in good agreement with those obtained from the smeared crack approach. It is concluded that the proposed model can be used in nonlinear static and dynamic analysis of concrete dams in 3D space and enables engineers to define the damage level of these infrastructures. The performance level of the considered system is used to assess the static and seismic safety using the defined performance based criteria.

• 시스템엔지니어링학술지
• /
• 제19권2호
• /
• pp.46-58
• /
• 2023

Deterministic safety analysis is a crucial part of safety assessment, particularly when it comes to demonstrating the safety of nuclear power plant designs. The traditional approach to deterministic safety analysis models is to model the nuclear core using point kinetics. However, this simplified approach does not fully reflect the real core behavior with proper moderator and fuel reactivity feedbacks during the transient. The use of Multi-Physics approach allows more precise simulation reflecting the inherent three-dimensionality (3D) of the problem by representing the detailed 3D core, with instantaneous updates of feedback mechanisms due to changes of important reactivity parameters like fuel temperature coefficient (FTC) and moderator temperature coefficient (MTC). This paper addresses a CEA ejection accident at hot full power (HFP), in which the underlying strong and un-symmetric feedback between thermal-hydraulics and reactor kinetics exist. For this purpose, a multi-physics analysis tool has been selected with the nodal kinetics code, 3DKIN, implicitly coupled to the thermal-hydraulic code, RELAP5, for real-time communication and data exchange. This coupled approach enables high fidelity three-dimensional simulation and is therefore especially relevant to reactivity initiated accident (RIA) scenarios and power distribution anomalies with strong feedback mechanisms and/or un-symmetrical characteristics as in the CEA ejection accident. The Systems Engineering approach is employed to provide guidance in developing the work in a systematic and efficient fashion.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.105.2-105.2
• /
• 2016

For the rational design and facile fabrication of novel nanostructures, we present a new approach to generating arrays of three-dimensionally tunable nanostructures by exploiting light-matter interaction. To create controlled three-dimensional (3D) nanostructures, we utilize the 3D spatial distribution of light, induced by the light-matter interaction, within the matter to be patterned. As a systematic approach, we establish 3D modeling that integrates the physical and chemical effects of the photolithographic process. Based on a comprehensive analysis of structural formation process and nanoscale features through this modeling, we are able to realize three-dimensionally tunable nanostructures using facile photolithographic process. Here we first demonstrate the arrays of three-dimensionally controlled, stacked nanostructures with nanoscale, tunable layers. We expect that the promising strategy would open new opportunities to produce the arrays of tunable 3D nanostructures using more accessible and facile fabrication process for various biomedical applications ranging from biosensors to drug delivery devices.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.1055-1058
• /
• 2003

The robustness and reliability of vision algorithms is the key issue in robotic research and industrial applications. In this paper robust real time visual tracking in complex scene is considered. A common approach to increase robustness of a tracking system is the use of different model (CAD model etc.) known a priori. Also fusion or multiple features facilitates robust detection and tracking of objects in scenes of realistic complexity. Voting-based fusion of cues is adapted. In voting. a very simple or no model is used for fusion. The approach for this algorithm is tested in a 3D Cartesian robot which tracks a toy vehicle moving along 3D rail, and the Kalman filter is used to estimate the motion parameters. namely the system state vector of moving object with unknown dynamics. Experimental results show that fusion of cues and motion estimation in a tracking system has a robust performance.

• Computers and Concrete
• /
• 제22권1호
• /
• pp.1-10
• /
• 2018

In this study an implicit algorithm for modeling of propagation of macrocracks in 3D concrete structures suffering from alkali-silica reaction has been developed and implemented. The formulation of the problem prior to the onset of localized deformation is based on a chemo-elasticity approach. The localized deformation mode, involving the formation of macrocracks, is described using a simplified form of the strong discontinuity approach (SDA) that employs a volume averaging technique enhanced by a numerical procedure for tracing the propagation path in 3D space. The latter incorporates a non-local smoothening algorithm. The formulation is illustrated by a number of numerical examples that examine the crack propagation pattern in both plain and reinforced concrete under different loading scenarios.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
• /
• pp.399-404
• /
• 1992

Curved 3D objects represented by range data contain large amounts of information compared with planar objects, but do not have distinct features for matching to those of object models. This makes it difficult to represent and identify a general 3D curved object. This paper introduces a new approach to representing and finding a holdsite of general 3D curved objects using range data. We develop a three-dimensional generalized Hough transformation which can be also applied to general 3D curved object recognition and which reduces both the computation time and storage requirements. Our approach makes use of the relative geometric differences between particular points on the object surface and some model points which are prespecified arbitrarily and task dependently.

• 산업공학
• /
• 제25권3호
• /
• pp.309-318
• /
• 2012

Forecasting probability or likelihood of technology development success has been a crucial factor for critical decisions in technology management such as R&D project selection and go or no-go decision of new product development (NPD) projects. This paper proposes an analytic network process (ANP) approach to forecasting of technology development success. Reviewing literature on factors affecting technology development success has constructed the ANP model composed of four criteria clusters : R&D characteristics, R&D competency, technological characteristics, and technological environment. An alternative cluster comprised of two elements, success and failure is also included in the model. The working of the proposed approach is provided with the help of a case study example of MRAM (magnetic random access memory) technology.

• Journal of Korean Neurosurgical Society
• /
• 제59권1호
• /
• pp.17-25
• /
• 2016

Objective : Treatment of intracranial dural arteriovenous fistulas (dAVFs) remains a challenge. However, after introduction of Onyx, transarterial approach is the preferred treatment option in many centers. We report our experience of dAVFs embolization with special emphasis on transarterial approach. Methods : Seventeen embolization procedures were performed in 13 patients with dAVFs between Jan 2009 and Oct 2014. Clinical symptoms, location and type of fistulas, embolization methods, complications, radiological and clinical outcomes were evaluated using charts and PACS images. Results : All 13 patients had symptomatic lesions. The locations of fistulas were transverse-sigmoid sinus in 6, middle fossa dura in 4, cavernous sinus in 2, and superior sagittal sinus in 1 patient. Cognard types were as follows : I in 4, IIa in 2, IIa+IIb in 5, and IV in 2. Embolization procedures were performed ${\geq}2$ times in 3 patients. Nine patients were treated with transarterial Onyx embolization alone. One of these required direct surgical puncture of middle meningeal artery. Complete obliteration of fistulas was achieved in 11/13 (85%) patients. There were no complications except for 1 case of Onyx migration in cavernous dAVF. Modified Rankin scale score at post-operative 3 months were 0 in 11, and 3 in 2 patients. Conclusion : Transarterial Onyx embolization can be a first line therapeutic option in patients with dAVFs. However, transvenous approach should be tried first in cavernous sinus dAVF because of the risk of intracranial migration of liquid embolic materials. Furthermore, combined surgical endovascular approach can be considered as a useful option in inaccessible route.

• 한국운동역학회지
• /
• 제15권3호
• /
• pp.105-115
• /
• 2005

This study was investigated the kinematic factors of the last approach strides and. take off motion for the skill improving of BKH elite male athlete. 'The subjects chosen for the study were BKH and. KASZCZYK Emillian male athletes who were participated in 2003 Dae-Gu Universiad Games. Three high speed video cameras set in 60frames/s setting were used. for recording from the last approach strides to the apex position. After digitizing motion, the Direct Linear Transformation(DLT) technique was employed to obtain 3-D position coordinates, The kinematic factors of the distance, velocity and angle variable were calculated for Kwon3D 3.1. The following conclusions were drawn; 1. It showed longer stride length, as well as faster horizontal and lateral velocity than the success trial during the approach phase. For consistent of the approach rhythm, it appeared that the subject should a short length for obtain the breaking force by the lower COG during the approach phase. 2. The body lean angle showed a small angle by a high COG during the take-off phase. For obtain the vertical displacement of the COG and a enough space form the bar after take-off, it appeared that the subject should increase the body lean angle. 3. For obtain the vertical force during the takeoff phase, it appeared that the subject should keep straight as possible the knee joint. Therefor, the subject can be obtain a enough breaking force at the approach landing.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제33권4호
• /
• pp.307-311
• /
• 2007

Purpose: The aim of this study was simply assessing linear measurements in the lateral and medial approach, respectively, for bone harvesting using anatomic and three-dimensional(3D) computed tomographic(CT) analyses on a dried cadaveric proximal tibia. In addition, the availability of the three-dimensional computed tomographic(3D-CT) analysis was also estimated. Materials and methods: Ten dried proximal tibia were obtained from five Korean cadavers. Four the reference points, the SM(superior-medial), IM(inferior-medial), SL(superior-lateral), and IL(inferior-lateral) were marked around the tibial tuberosity. The PM(posterior-medial) and PL(posterior-lateral) points were randomly marked at points farthest from the lateral and medial reference points, respectively, in the posterior border of the superior articular surface of both condyles. All measurements were obtained on the dried proximal tibia. After computed tomography had been performed, the three dimensional images were reconstructed using V works $4.0^{TM}$(Cybermed Inc., Seoul, Korea), and the length between the reference points were measured three dimensionally using the method described above. The error between the mean actual and mean 3D-CT measurements was calculated in order to determine the availability of the three dimensional computed tomographic analysis. Results: The length between the reference points was greatest at the IL-PM, which averaged $65.39mm{\pm}10.35$. This was followed by the SL-PM with $63.24mm{\pm}8.10$, the IM-PL with $58.09mm{\pm}10.02$, and the SM-PL with $51.99mm{\pm}9.06$. The differences between the IL-PM and SM-PL were 13.4 mm. The mean values were 55.04 mm in the medial approach and 64.32 mm in the lateral approach, and the differences between medial and lateral were 9.28 mm. The error between the mean actual and mean 3D-CT measurements was 0.31% and the standard deviation was 0.28%. Conclusion: The anatomical and three dimensional computed tomographic analysis indicates that there was only a 9.28 mm linear difference between the lateral and medial approach. This is consistent with previous studies, which showed that there was little difference between the two approaches in terms of the bone volume. In addition, the error(0.31%) and the standard deviation(0.28%) were considered low, demonstrating high accuracy of 3D-CT. Therefore it can be used in preoperative treatment planning.