• 한국정보통신설비학회:학술대회논문집
• /
• 한국정보통신설비학회 2007년도 학술대회
• /
• pp.251-255
• /
• 2007

In this paper, propagation analysis method in using 3D Ray Tracing propagation model in wireless cell planning is proposed. Through 3D Ray Tracing model, we can predict the distribution of propagation loss of the received signal. For correct and a low complex analysis, Quad Tree and Pre-Ordering and Hash Function algorithms are included in 3D Ray Tracing algorithm. And 3D Ray Tracing model is embodied in CellTREK that is developed by KT and used to plan Wibro system analysis. In CellTREK, propagation analysis is performed and that result is represented in 3D viewer. In numerical results, it is showed that the proposed scheme outperforms Modified HATA model when comparing with measurement data.

• 한국정밀공학회지
• /
• 제32권1호
• /
• pp.75-81
• /
• 2015

Modeling and analysis using a ray tracing method for internal defects were described. Reflection and refraction of rays on the interface of defects were modeled using the Harvey model and the Lambertian model. The diffraction on the interface of defects affected the incoming signals and it could evaluate any defects in the matter and its signal would be analyzed with the ray tracing simulation. The simulation results were compared with actual detecting signals and the ray tracing model was shown in good agreement with experimental data. This method has a possibility to be used as wave propagation modeling in non-destructive testing.

• Journal of Information Display
• /
• 제9권3호
• /
• pp.33-38
• /
• 2008

A simple ray tracing model is developed to establish the relationship between the distributions of observed visible light and the excited Xe species in a PDP cell. The ray tracing model can obtain the density distribution of the excited Xe species. It shows the two independent discharge modes created during a single period of sustaining discharge. The maximum density of excited Xe species is located about $148{\mu}m$ away from the center of the gap between two sustaining electrodes. We also found the loss rate of VUV photons by comparing the luminance profile predicted in our theoretical model from experimental results. According to calculations based on our model, only about 22 percent of the photons can impinge the phosphor layer.

• IEIE Transactions on Smart Processing and Computing
• /
• 제5권4호
• /
• pp.289-293
• /
• 2016

As more mobile devices are equipped with multi-core CPUs and are required to execute many compute-intensive multimedia applications, it is important to optimize the systems, considering the underlying parallel hardware architecture. In this paper, we implement and optimize ray-tracing application tailored to a given mobile computing platform with multiple heterogeneous processing elements. In this paper, a lightweight ray-tracing application is specified and implemented in Kahn process network (KPN) model-of-computation, which is known to be suitable for the description of real-time applications. We take an open-source C/C++ implementation of ray-tracing and adapt it to KPN description in the Distributed Application Layer framework. Then, several possible configurations are evaluated in the target mobile computing platform (Exynos 5422), where eight heterogeneous ARM cores are integrated. We derive the optimal degree of parallelism and a suitable distribution of the replicated tasks tailored to the target architecture.

• 소음진동
• /
• 제9권6호
• /
• pp.1131-1136
• /
• 1999

NIC@E is the software developed by authors. The program provides the noise level in outdoors due to various noise source types : construction machines including blast sources, railroad vehicles and automobiles. It operates in the Windows system. In this paper, a highway traffic noise has been evaluated using various types of approach : Ray-tracing method, NIRI method, JAS method. In order to compare the noise estimation performance for various models, a measurement is conducted on a 8 lane express highway at the distance of 25 m and 50 m from the lane. The result shows that the ray tracing and JAS model predict the measured value well within 2dB deviaton. The NIRI model, however, underestimates the highway noise level, as the distance between the source and receiver increases.

• 한국전자파학회논문지
• /
• 제18권11호
• /
• pp.1231-1236
• /
• 2007

본 논문에서는 무선 망 설계에 필요한 전파 특성 예측을 위한 방법 중 하나인 광선 추적법의 속도 향상 방법을 제시했다. 빠르고 정확한 광선 추적을 위해 ray tube라는 매개체를 이용하여 전파의 반사, 투과, 회절을 계산하는데, 건물 등의 방해물이 많을수록 계산 시간이 매우 늘어나는 문제점을 해결하기 위해 중복된 계산을 줄이는 방법들을 제시했다.

• 한국공간정보시스템학회:학술대회논문집
• /
• 한국공간정보시스템학회 2003년도 추계학술대회
• /
• pp.159-162
• /
• 2003

In this paper, to find probable collision positions between moving object and terrain in 3D space efficiently, we use a model, similar to Ray Tracing, which finds the triangles intersected by a directed line segment from a large amount of triangles. We try to reduce dead space as much as possible to find candidate triangles intersected by a directed line segment than previous work's. A new modified octree, LBV-Octree(Least Bounding Voxel Octree), is proposed, and we have a ray tracing with it. In the experiment, ray tracing with LBV-Octree provides $5%{\sim}11%$ better performance than with classical octree.

• The Journal of the Acoustical Society of Korea
• /
• 제20권3E호
• /
• pp.10-17
• /
• 2001

The possibility is investigated of determining the diffuse absorption coefficients of the wall surfaces in a real room by minimizing the errors between the measured energy impulse response of a real room and the predicted energy impulse responses obtained from the ray tracing simulation of the room. In other words, this can possibly serve as a basis for "acoustical system identification" in attempting to determine the "best fit" of modelled absorption coefficients to measured energy response data. Algorithms for attempting this were investigated. The algorithms developed for this purpose proved to be rigorous and efficient. Instead of using the ray tracing model to determine the absorption coefficients, the phase image model was used in order to determine the acoustic impedances of wall surfaces. However, the numerical algorithms could not find the correct impedance values, primarily due to the wide range of the acoustic impedance values of any single acoustic material and very long computation time.

• 한국전자파학회논문지
• /
• 제15권8호
• /
• pp.759-764
• /
• 2004

본 논문에서는 3D 광선추적법에 기반한 전파 예측 모델을 이용하여 MIMO 채널 특성을 해석적으로 분석하는 방법을 제시한다. 경로들의 위상차를 고려하여 채널간 discrete spatial correlation을 계산하고 이를 이용하여 젠센 부등식을 이용해 평균 MIMO채널 용량의 최대치를 추정한다. 본 해석 모델은 측정을 통한 통계적 접근이나 Monte-Carlo 시뮬레이션을 통한 확률적 접근을 하지 않는 결정적인 모델이므로 시간과 비용측면에서 큰 효율을 가진다. 또한 전파 이론에 기초한 방법이므로 채널 용량에 영향을 미칠 수 있는 안테나 패턴이나 편파, 상호간섭, 안테나 구조 등의 파라미터를 정량적으로 분석 할 수 있는 장점이 있다. 본 모델은 MIMO 시스템에 적합한 안테나 구조 등의 개발에 이용될 수 있을 것이다.

• 한국측량학회지
• /
• 제38권2호
• /
• pp.141-151
• /
• 2020

Since it was first studied in 1980, solar energy analysis model for geographic information systems has been used to determine the approximate spatial distribution of terrain. However, the spatial pattern was not able to be grasped in 3D (three-dimensional) space with low accuracy due to the limitation of input data. Because of computational efficiency, using a constant value for the brightness of the sky caused the simulation results to be less reliable especially when the slope is high or buildings are crowded around. For the above reasons, this study proposed a model that predicts solar energy of vertical surfaces of buildings with four stages below. Firstly, CIE (Commission Internationale de l'Eclairage) luminance distribution model was used to calculate the brightness distribution of the sky using NREL (National Renewable Energy Laboratory) solar tracking algorithm. Secondly, we suggested a method of calculating the shadow effect using ray tracing. Thirdly, LOD (Level of Detail) 3 of 3D spatial data was used as input data for analysis. Lastly, the accuracy was evaluated based on the atmospheric radiation data collected through the ground observation equipment in Daejeon, South Korea. As a result of evaluating the accuracy, NMBE was 5.14%, RMSE 11.12, and CVRMSE 7.09%.