• Journal of the Korea Society of Computer and Information
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• 제4권1호
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• pp.54-61
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• 1999

The MRP, OPT and JIT systems have the respective limitations to become the suitable production management systems of the future. Therefore it is highly requested to develop an integrated production management system by the hybridization of those production systems. Accordingly, this study has focused its hybrid model using MRP, JIT and OPT. There has been many efforts in comparing and analyzing the usefulness and the limitations of those production systems and applying the usefulness to the maximum which improving and supplementing the weakpoints of respective systems. In this respect, this study develop the hybrid simulation model, and this hybrid model are evaluated and compared with MRP(Push system) and JIT(Pull system) by using a simulation.

• The korean journal of orthodontics
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• 제41권6호
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• pp.411-422
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• 2011

Objective: The aim of this study was to evaluate the lip and perioral soft tissue changes after bracket bonding. Methods: The soft tissue changes in 45 adult patients (age greater than 18 years and less than 29 years) without severe skeletal discrepancy were evaluated using three-dimensional images acquired with a laser scanner before and after bracket bonding was performed using 4 types of labial orthodontic brackets. Results: Among the statistically significant changes in distance observed for the landmarks, the biggest change was observed in forward movement. The landmarks on the lateral sides also showed significant changes. While the landmarks on the upper lip showed significant upward movement, those on the lower lip showed significant downward movement. However, the changes were smaller for the landmarks on the upper lip (average, 0.87 mm) than for the landmarks on the lower lip (average, 1.21 mm). The type of bracket used did not significantly affect the soft tissue changes. Conclusions: These findings will help predict soft tissue changes after bracket bonding for orthodontic treatment.

• Journal of the Society of Naval Architects of Korea
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• 제36권3호
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• pp.15-21
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• 1999

The flow characteristics around KRISO 300K VLCC double-body model have been experimentally investigated in a closed-type subsonic wind tunnel. The local mean velocity and turbulence statistics including turbulent intensity. Reynolds shear stress and turbulent kinetic energy were measured using a x-type hot-wire probe. The measurements were carried out at several transverse stations of the stern and near wake regions. The surface flow was visualized using on oil-film technique to see the flow pattern qualitatively. The flow in the stern and near wake region revealed complicated three-dimensional flow characteristics. The VLCC model shows a hook-shaped wake structure behind the propeller boss in the main longitudinal vortex region. The thin boundary layer at midship was increased gradually in thickness over the stern and evolved into a full three-dimensional turbulent wake.

• Journal of the Korean Society of Manufacturing Process Engineers
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• 제18권8호
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• pp.98-103
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• 2019

A more accurate method of feature point extraction and matching for three-dimensional reconstruction using low-resolution images of crops is proposed herein. This method is important in basic computer vision. In addition to three-dimensional reconstruction from exact matching, map-making and camera location information such as simultaneous localization and mapping can be calculated. The results of this study suggest applicable methods for low-resolution images that produce accurate results. This is expected to contribute to a system that measures crop growth condition.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 1부
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• pp.414-419
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• 2008

3D rendering is a critical process for a movie production, advertisement, interior simulation, medical and many other fields. Recently, several effective rendering methods have been developed for the photo-realistic image generation. With a rapid performance enhancement of graphics hardware, physically based 3D rendering algorithm can now often be approximated in real-time games. However, the high quality of global illumination, required for the image generation in the 3D animation production community is a still very expensive process. In this paper, we propose a new rendering method to create photo-realistic global illumination effect efficiently by harnessing the high power of the recent GPUs. Final gathering routines in our global illumination module are accelerated by programmable graphics hardware. We also simulate physically based light transport on a ray tracing based rendering algorithm with photon mapping effectively.

• Geophysics and Geophysical Exploration
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• 제17권4호
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• pp.209-215
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• 2014

In order to develop a new mineral exploration technique, a study was carried out about the potential mapping of Moisan area using SIP (Spectral Induced Polarization) data. The SIP inversion results were classified according to the geological regions, and the distribution characteristics of resistivity and phase values of SIP data were analyzed at the ore region. Based on the characteristics of SIP of ore bodies, we performed 3D potential mapping of Moisan area. The analyzed potential map was verified using that the locations and patterns of high potential regions of the results are well matched with those of the known ore bodies. If we get the higher spatial resolution SIP data, the potential mapping technique using SIP data can be effectively applied to the estimation of mining deposit.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• 제38권6호
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• pp.611-622
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• 2020

As the advancement of technologies on indoor positioning systems and measuring devices such as LiDAR (Light Detection And Ranging) and cameras, the demands on analyzing and searching indoor spaces and visualization services via virtual and augmented reality have rapidly increasing. To this end, it is necessary to model 3D objects from measured data from real-world structures. In addition, it is important to store these structured data in standardized formats to improve the applicability and interoperability. In this paper, we propose a method to construct IndoorGML data, which is an international standard for indoor modeling, from point cloud data acquired from LiDAR sensors. After examining considerations that should be addressed in IndoorGML data, we present a construction method, which consists of free space extraction and connectivity detection processes. With experimental results, we demonstrate that the proposed method can effectively reconstruct the 3D model from point cloud.

• Korean Journal of Bronchoesophagology
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• 제1권1호
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• pp.82-93
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• 1995

Three-dimensional reconstruction of computed tomographic image(3D CT) is a well-established imaging modality which has been investigated in various clinical settings. It is commonly performed in case of congenital or developmental abnormalities, and traumatic fracture of skull and face that requires reconstruction of osseous structure. However reporting the 3D CT in laryngeal or tracheal stenosis is rare and its results are obscure. The authors performed 3D CT in six cases of tracheal stenosis and found diagnostic value of 3D CT. A Comparision of diagnostic information obtained from plain X-ray, 2D CT and 3D CT has performed in total six cases of tracheal stenosis. Surgical treatment of the tracheal stenosis was following in these cases : tracheal end to end anastomosis In 1 case, laryngotracheal end to end anastomosis in 2 cases. 3D CT information was compared with operative finding. In two of six cases, satisfactory information was not obtained from 3D CT in evaluating an exact stenosis of trachea. Future, it will be helped in evaluating of tracheal stenosis by 3D CT.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 한국방송∙미디어공학회 2022년도 하계학술대회
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• pp.836-838
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• 2022

3D Point Cloud는 3D 콘텐츠를 더욱 실감 나게 표현하기 위한 데이터 포맷이다. Point Cloud 데이터는 3차원 공간상에 존재하는 데이터로 기존의 2D 영상에 비해 거대한 용량을 가지고 있다. 최근 대용량 Point Cloud의 3D 데이터를 압축하기 위해 V-PCC(Video-based Point Cloud Compression)와 같은 다양한 방법이 제시되고 있다. 따라서 Point Cloud 데이터의 원활한 전송 및 저장을 위해서는 V-PCC와 같은 압축 기술이 요구된다. V-PCC는 Point Cloud의 데이터들을 Patch로써 뜯어내고 2D에 Projection 시켜 3D의 영상을 2D 형식으로 변환하고 2D로 변환된 Point Cloud 영상을 기존의 2D 압축 코덱을 활용하여 압축하는 기술이다. 이 V-PCC로 변환된 2D 영상은 기존 2D 영상을 전송하는 방식을 활용하여 네트워크 기반 전송이 가능하다. 본 논문에서는 V-PCC 방식으로 압축한 V3C 데이터를 방송망으로 전송 및 소비하기 위해 MPEG Media Transport(MMT) Packet을 만드는 패킷화 방안을 제안한다. 또한 Server와 Client에서 주고받은 V3C(Visual Volumetric Video Coding) 데이터의 비트스트림을 비교하여 검증한다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• 제12권2호
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• pp.70-80
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• 2000

Princeton Ocean Model (POM) is modified to construct a three-dimensional, semi-implicit hydro¬dynamic model with a wetting-and-drying scheme. The model employs semi-implicit treatment of the barotropic pressure gradient terms and the vertical mixing terms in the momentum equations, and the velocity divergence term in the vertically-integrated continuity equation. Such treatment removes the external mode and thus the mode splitting scheme in POM, allowing the semi-implicit model to use a larger time step. Applied to hypothetical systems, both the semi-implicit model and POM give nearly the same results. The semi-implicit model, however, runs approximately 4.4 times faster than POM showing its improved computational efficiency. Applied to a hypothetical system with intertidal flats, POM employing the mode splitting scheme produces noises at the intertidal flats, that propagate into the main channel resulting in unstable current velocities. Despite its larger time step, the semi-implicit model gives stable current velocities both at the intertidal flats and main channel. The semi-implicit model when applied to Kyeonggi Bay gives a good reproduction of the observed tides and tidal currents throughout the modeling domain, demonstrating its prototype applicability.