• Journal of the Society of Disaster Information
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• v.15 no.3
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• pp.427-439
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• 2019

Purpose: We generated geospatial information of unmanned aerial vehicle based on various SW and analyzed the location accuracy of orthoimage and DSM and texture mapping of 3D mesh. Method: The same unmanned aerial image data is processed using two different SW, and spatial information is generated. Among the generated spatial information, the orthoimage and DSM were compared with the spatial information generation results of the unmanned aerial photogrammetry SW by performing quantitative analysis by calculating RMSE of horizontal position and vertical position error and performing qualitative analysis. Results: There were no significant differences in the positional accuracy of the orthoimage and DSM generated by each SW, and differences in texture mapping in 3D mesh. The creation of the 3D mesh indicated the impact of the Unmanned Aerial Photogrammetry SW. Conclusion: It is shown that there is no effect of SW on the creation of orthoimage and DSM for geospatial analysis based on unmanned aerial vehicle. However, when 3D visualization is performed, texture mapping results are different depending on SW.

• Journal of the Korean GEO-environmental Society
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• v.13 no.8
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• pp.57-64
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• 2012

The lateral behavior characteristics of concrete group pile under the lateral load were examined by the laboratory model tests in this study. Piles were socketed 1D(D : pile diameter) in the concrete block, and model tests were executed on $2{\times}3$ group piles, of which the length were 11D, 15D and 20D. All results of loading tests under each condition was presented by the lateral load-displacement curves, and the displacements in the ground under the lateral loads were measured. As a results of model tests, as the ratio of pile length/diameter(L/D) was decreased, the yielding load and the lateral displacement at that load were increased. The yielding load was evaluated as the load at lateral displacement of 15 mm. The yielding loads at the pile length of 11D, 15D and 20D were 11.7, 6.2kN and 3.4kN. The lateral displacements of pile in the ground under each condition were measured linearly and the failure occurred at the location where the piles were socketed in concrete block.

• Journal of IKEEE
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• v.16 no.2
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• pp.102-108
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• 2012

3-dimensional integrated circuits (3D-ICs) have some problems for power delivery network design due to larger supply currents and larger power delivery paths compared to 2D-IC. The power delivery network consists of power bumps & through-silicon-vias (TSVs), and IR-drop at each node varies with the number and location of power bumps & TSVs. It is important to optimize the power bumps & TSVs while IR-drop constraint is satisfied in order to operate chip ordinarily. In this paper, the power bumps & TSVs optimization with optimized power mesh structure for power delivery network in 3D-ICs is proposed.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.235-237
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• 2004

최근 급속히 발전하고 있는 유비쿼터스 컴퓨팅의 대두는 센서네트워크 산업 발전에 않은 영향을 끼치고 있다. 센서네트워크는 군사, 과학, smart home, 환경, 농업등 많은 분야에 응용할 수 있으며, 기존의 유무선 네트워크와 항께 미래를 같이할 차세대 네트워크로 평가 받고 있다. 본 논문에서는 저전력 무선 센서네트워크인 MICA2[1]를 이용하여, room size의 건물내의 공간에서 3자원위치를 인식 및 추적 할 수 있는 저가형 시스템에 대하여 설계 및 구현한다.

• Journal of Broadcast Engineering
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• v.21 no.2
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• pp.252-260
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• 2016

The performance of human detection system is affected by camera location and view angle. In 2D image acquired from such camera settings, humans are displayed in different sizes. Detecting all the humans with diverse sizes poses a difficulty in realizing a real-time system. However, if the size of a human in an image can be predicted, the processing time of human detection would be greatly reduced. In this paper, we propose a method that estimates human size by constructing an indoor scene in 3D space. Since the human has constant size everywhere in 3D space, it is possible to estimate accurate human size in 2D image by projecting 3D human into the image space. Experimental results validate that a human size can be predicted from the proposed method and that machine-learning based detection methods can yield the reduction of the processing time.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2089-2094
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• 2003

The flow around a circular cylinder was controlled by attaching O-rings to reduce drag force acting on the cylinder. Four experimental models were tested in this study; one smooth cylinder of diameter D (D=60mm) and three cylinders fitted with O-rings of diameters d=0.0167D, 0.05D and 0.067D with pitches of PPD=1D, 0.5D and 0.25D. The drag force, mean velocity and turbulent intensity profiles in the near wake behind the cylinders were measured for Reynolds numbers based on the cylinder diameter in the range of $Re_D=7.8{\times}10^3{\sim}1.2{\times}10^5$. At $Re_D=1.2{\times}10^5$, the cylinder fitted with O-rings of d=0.0167D in a pitch interval of 0.25D shows the maximum drag reduction of about 5.4%, compared with the smooth cylinder. The drag reduction effect of O-rings of d=0.067D is not so high. For O-ring circulars, as the Reynolds number increases, the peak location of turbulence intensity shifts downstream and the peak magnitude is decreased. Flow field around the cylinders was visualized using a smoke-wire technique to see the flow structure qualitatively. The size of vortices and vortex formation region formed behind the O-ring cylinders are smaller, compared with the smooth cylinder.

• The Journal of Korean Society for Radiation Therapy
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• v.16 no.1
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• pp.57-65
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• 2004

Introduction : The phantom that includes high density materials such as steel was custom-made to fix lung and bone in order to evaluation inhomogeneity correction at the time of conducting radiation therapy to treat lung cancer. Using this, values resulting from the inhomogeneous correction algorithm are compared on the 2 and 3 dimensional radiation therapy planning systems. Moreover, change in dose calculation was evaluated according to inhomogeneous by comparing with the actual measurement. Materials and Methods : As for the image acquisition, inhomogeneous correction phantom(Pig's vertebra, steel(8.21g/cm3), cork(0.23 g/cm3)) that was custom-made and the CT(Volume zoom, Siemens, Germany) were used. As for the radiation therapy planning system, Marks Plan(2D) and XiO(CMS, USA, 3D) were used. To compare with the measurement value, linear accelerator(CL/1800, Varian, USA) and ion chamber were used. Image, obtained from the CT was used to obtain point dose and dose distribution from the region of interest (ROI) while on the radiation therapy planning device. After measurement was conducted under the same conditions, value on the treatment planning device and measured value were subjected to comparison and analysis. And difference between the resulting for the evaluation on the use (or non-use) of inhomogeneity correction algorithm, and diverse inhomogeneity correction algorithm that is included in the radiation therapy planning device was compared as well. Results : As result of comparing the results of measurement value on the region of interest within the inhomogeneity correction phantom and the value that resulted from the homogeneous and inhomogeneous correction, gained from the therapy planning device, margin of error of the measurement value and inhomogeneous correction value at the location 1 of the lung showed $0.8\%$ on 2D and $0.5\%$ on 3D. Margin of error of the measurement value and inhomogeneous correction value at the location 1 of the steel showed $12\%$ on 2D and $5\%$ on 3D, however, it is possible to see that the value that is not correction and the margin of error of the measurement value stand at $16\%$ and $14\%$, respectively. Moreover, values of the 3D showed lower margin of error compared to 2D. Conclusion : Revision according to the density of tissue must be executed during radiation therapy planning. To ensure a more accurate planning, use of 3D planning system is recommended more so than the 2D Planning system to ensure a more accurate revision on the therapy plan. Moreover, 3D Planning system needs to select and use the most accurate and appropriate inhomogeneous correction algorithm through actual measurement. In addition, comparison and analysis through TLD or film dosimetry are needed.

• The KIPS Transactions:PartD
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• v.12D no.5 s.101
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• pp.689-698
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• 2005

Various systems are used to provide the location based services. But, the existing systems have some problems which have difficulties in dealing with faster services for above million people. In order to solve it, a multi-level DBMS which supports both fast data processing and large data management support should be used. The multi-level DBMS with snapshots has all the data existing in disk database and the data which are required to be processed for fast processing are managed in main memory database as snapshots. To optimize performance of this system for location based services, the query classification component which classifies the queries for efficient snapshot usage is needed. In this paper, the query classification component in multi-level DBMS for location based services is designed and implemented. The proposed component classifies queries into three types: (1) memory query, (2) disk query, (3) hybrid query, and increases the rate of snapshot usage. In addition, it applies division mechanisms which divide aspatial and spatial filter condition for partial snapshot usage. Hence, the proposed component enhances system performance by maximizing the usage of snapshot as a result of the efficient query classification.

• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.436-443
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• 2008

This paper presents a new method for building detection and reconstruction from aerial images. In our approach, we extract useful building location information from the generated disparity map to segment the interested objects and consequently reduce unnecessary line segments extracted in the low level feature extraction step. Hypothesis selection is carried out by using an undirected graph, in which close cycles represent complete rooftops hypotheses. We test the proposed method with the synthetic images generated from Avenches dataset of Ascona aerial images. The experiment result shows that the extracted 3D line segments of the reconstructed buildings have an average error of 1.69m and our method can be efficiently used for the task of building detection and reconstruction from aerial images.

• Tunnel and Underground Space
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• v.12 no.1
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• pp.10-18
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• 2002

Rock joint system makes a heavy effect on the behavior of rock structures. The definition of a 3D rock joint system is very important in 2D or 3D numerical analysis for the prediction of the behavior of a discontinuous rock mass. To enhance the reality of a 3D definition of rock joint system, it is essential to estimate the unbiased statistics of basic geometric attributes of rock joints. In this study, we have proposed the statistical analysis and derived the related equations for an estimation of statistics of joint size and intensity. Geometry of rock joints in 3 dimensional space can be defined by the aggregate of location, size, orientation and intensity. The dimensional limit of survey method and its data makes 3D geometric attributes probabilistic. In the estimation of statistics of joint size, we have discussed the technique to correct the bias from a dimensional limit and derived the equation of 3D joint intensity by stereological approaches.