• Title/Summary/Keyword: view-dependent simulation

Search Result 27, Processing Time 0.035 seconds

View-Dependent Adaptive Animation of Liquids

  • Kim, Jang-Hee;Ihm, In-Sung;Cha, Deuk-Hyun
    • ETRI Journal
    • /
    • v.28 no.6
    • /
    • pp.697-708
    • /
    • 2006
  • Various adaptive mesh refinement techniques are often employed in numerical simulations for increasing spatial and temporal resolution beyond the limits imposed by available CPU time and memory space. Recently, an octree-based adaptive mesh structure was successfully used in fluid animation to place more grid cells efficiently in visually interesting regions of fluids. In an attempt to optimize the use of computational resources further in fluid animation, this paper extends this adaptive technique by modifying the mesh refinement scheme so that the camera's viewing properties are dynamically exploited during the simulation. Based on a simple adaptive mesh structure, we show that the new meshing strategy can save a substantial amount of computation time and memory space by using a view-dependent adaptive approach. The experimental results reveal that the proposed technique provides a good compromise between the computational effort and the simulation's fidelity, and may be used quite effectively in 3D animation production.

  • PDF

Real-Time Terrain Rendering using Quadtree Wavelet Transform (쿼드트리와 웨이블릿 변환을 이용한 실시간 지형 렌더링)

  • 한정현;박헌기;정문주
    • Journal of the Korea Society for Simulation
    • /
    • v.10 no.3
    • /
    • pp.95-103
    • /
    • 2001
  • Rendering of 3D terrain data in real-time is difficult because of its large scale. So, it is necessary to use level-of-detail(LOD) that uses fewer data, but makes almost similar image to the original. We present an algorithm for real-time LOD generation and rendering of 3D terrain data. The algorithm applies wavelet transform to the terrain data, and then generates quadtree based view-dependent LOD using wavelet coefficients that are the output of wavelet transform. It also uses frame-to-frame coherence and view culling for high frame rates.

  • PDF

Coding Technique using Depth Map in 3D Scalable Video Codec (확장된 스케일러블 비디오 코덱에서 깊이 영상 정보를 활용한 부호화 기법)

  • Lee, Jae-Yung;Lee, Min-Ho;Chae, Jin-Kee;Kim, Jae-Gon;Han, Jong-Ki
    • Journal of Broadcast Engineering
    • /
    • v.21 no.2
    • /
    • pp.237-251
    • /
    • 2016
  • The conventional 3D-HEVC uses the depth data of the other view instead of that of the current view because the texture data has to be encoded before the corresponding depth data of the current view has been encoded, where the depth data of the other view is used as the predicted depth for the current view. Whereas the conventional 3D-HEVC has no other candidate for the predicted depth information except for that of the other view, the scalable 3D-HEVC utilizes the depth data of the lower spatial layer whose view ID is equal to that of the current picture. The depth data of the lower spatial layer is up-scaled to the resolution of the current picture, and then the enlarged depth data is used as the predicted depth information. Because the quality of the enlarged depth is much higher than that of the depth of the other view, the proposed scheme increases the coding efficiency of the scalable 3D-HEVC codec. Computer simulation results show that the scalable 3D-HEVC is useful and the proposed scheme to use the enlarged depth data for the current picture provides the significant coding gain.

On-orbit test simulation for field angle dependent response measurement of the Amon-Ra energy channel instrument

  • Seong, Sehyun;Kim, Sug-Whan;Ryu, Dongok;Hong, Jinsuk;Lockwood, Mike
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.37 no.2
    • /
    • pp.211.1-211.1
    • /
    • 2012
  • The on-orbit test simulation for predicting the instrument directional responsivity was conducted by the Monte Carlo based integrated ray tracing (IRT) computation technique and analytic flux-to-signal conversion algorithms. For the on-orbit test simulation, the Sun model consists of the Lambertian scattering sphere and emitting spheroid rays, the Amon-Ra instrument is a two-channel including a broadband scanning radiometer (energy channel) and an imager with ${\pm}2^{\circ}$ FOV (visible channel). The solar radiation produced by the Sun model is directed to the instrument viewing port and traced through the dual channel optical train. The instrument model is rotated on its rotation axis and this gives a slow scan of the Sun model over the full field of view. The direction of the incident lights are fed with scanned images obtained from the visible channel instrument. The instrument responsivity was computed by the ratio of the incident radiation input to the instrument output. In the radiometric simulation, especially, measured BRDF of the 3D CPC was used for scattering effects on radiometry. With diamond turned 3D CPC inner surface, the anisotropic surface scattering model from the measured data was applied to ray tracing computation. The technical details of the on-orbit test simulation are presented together with field-of-view calibration plan.

  • PDF

Fast Disparity Motion Vector Searching Method for the MV-HEVC (MV-HEVC에서 빠른 변위 움직임 벡터 탐색 방법)

  • Lee, Jae-Yung;Han, Jong-Ki
    • Journal of Broadcast Engineering
    • /
    • v.22 no.2
    • /
    • pp.240-252
    • /
    • 2017
  • Multi-view video codec based on the High Efficiency Video Coding (MV-HEVC) has high encoding complexity because it exploits an additional reference picture for disparity compensation prediction (DCP) when the picture of dependent view is encoded. In this paper, we propose an efficient method to reduce the complexity of disparity motion vector search for the MV-HEVC. The proposed method includes the initial search point decision method using affine transform and the adaptive search range decision method. The simulation results show that the proposed method reduces the complexity of disparity motion vector search up to 90.78% with negligible coding efficiency degradation. Also the results show that the proposed method outperforms other conventional techniques reducing complexity.

Re-examining Network Market Strategies from the Perspective of the Local Network: Market Competition between Incompatible Technologies

  • Choi, Han-Nool;Lee, Byung-Tae
    • Proceedings of the Korean Operations and Management Science Society Conference
    • /
    • 2005.10a
    • /
    • pp.189-206
    • /
    • 2005
  • Much of work on network externality assumed network effects are dependent on the network size. Therefore, very little consideration is given to the view that marginal benefits from joining the network may not increase with the network size if consumer benefits come from the direct interaction with neighbors, namely local network. In this study, we used the agent-based simulation method to reexamine the effectiveness of the traditional network market strategy under the presence of the local network where two incompatible technologies compete. We found that the strategy of growing an initial customer base is not effective under the presence of the local network. Our study also showed that targeting customers based on their technology Preference is not as effective as targeting customers within the same local network. As a result, the focus of a network market strategy should be directed to taking advantage of the customer network.

  • PDF

Simulated Optimum Substrate Thicknesses for the BC-BJ Si and GaAs Solar Cells

  • Choe, Kwang-Su
    • Korean Journal of Materials Research
    • /
    • v.22 no.9
    • /
    • pp.450-453
    • /
    • 2012
  • In crystalline solar cells, the substrate itself constitutes a large portion of the fabrication cost as it is derived from semiconductor ingots grown in costly high temperature processes. Thinner wafer substrates allow some cost saving as more wafers can be sliced from a given ingot, although technological limitations in slicing or sawing of wafers off an ingot, as well as the physical strength of the sliced wafers, put a lower limit on the substrate thickness. Complementary to these economical and techno-physical points of view, a device operation point of view of the substrate thickness would be useful. With this in mind, BC-BJ Si and GaAs solar cells are compared one to one by means of the Medici device simulation, with a particular emphasis on the substrate thickness. Under ideal conditions of 0.6 ${\mu}m$ photons entering the 10 ${\mu}m$-wide BC-BJ solar cells at the normal incident angle (${\theta}=90^{\circ}$), GaAs is about 2.3 times more efficient than Si in terms of peak cell power output: 42.3 $mW{\cdot}cm^{-2}$ vs. 18.2 $mW{\cdot}cm^{-2}$. This strong performance of GaAs, though only under ideal conditions, gives a strong indication that this material could stand competitively against Si, despite its known high material and process costs. Within the limitation of the minority carrier recombination lifetime value of $5{\times}10^{-5}$ sec used in the device simulation, the solar cell power is known to be only weakly dependent on the substrate thickness, particularly under about 100 ${\mu}m$, for both Si and GaAs. Though the optimum substrate thickness is about 100 ${\mu}m$ or less, the reduction in the power output is less than 10% from the peak values even when the substrate thickness is increased to 190 ${\mu}m$. Thus, for crystalline Si and GaAs with a relatively long recombination lifetime, extra efforts to be spent on thinning the substrate should be weighed against the expected actual gain in the solar cell output power.

Study on Multi-point Dieless Forming Technology Based on Numerical and Experimental Approach (수치 및 실험적 접근을 통한 다점무금형성형기술 연구)

  • Heo, S.C.;Seo, Y.H.;Ku, T.W.;Song, W.J.;Kim, J.;Kang, B.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2008.05a
    • /
    • pp.220-223
    • /
    • 2008
  • Large curved plate blocks are widely used to construct hull structure in shipbuilding industry. Most curved plates are manufactured by using manual method called as line heating that use deformation caused by residual stress after local heating along a line which is perpendicular to the curvature direction. However, its working environment is poor and its formability is totally dependent on an experienced technician. In view of that, multi-point dieless forming (MDF) technology that use reconfigurable punch arrays instead of one piece die is proposed in this study. The MDF process is based on a concept of equivalent die surface made by numbers of punches which has round tip at the end of it. In this study, numerical simulation for common curvature type such as saddle shape was carried out. In addition, experiments in the plate forming process were also conducted to compare with the numerical results in view of final configuration. Consequently, it was noted that the proposed dieless forming method has considerable feasibility to substitute the new process for conventional manual method.

  • PDF

CSD-WRR Algorithm for Improving Fairness in Wireless Network (무선망에서 공평성 향상을 위한 CSD-WRR 알고리즘)

  • Choi, Seung-Kwon;Shin, Byung-Gon;Lee, Byung-Rok
    • Proceedings of the Korea Contents Association Conference
    • /
    • 2006.05a
    • /
    • pp.132-135
    • /
    • 2006
  • Recently, multimedia data service using mobile terminal has been increased according to the development of wireless network technology which can be used in an indoor or outdoor environment. However, the wireless network shares the channel and it has a high error rate because of characteristics of transmission media. Therefore, it has a lot of problems for guaranteeing QoS(Quality of Services) in various requirements. This paper suggests a CSD-WRR(Channel State Dependent-WRR) method for compensating the service rate considering the transmission deadline. Simulation results show that the suggested method outperforms the conventional WRR in the view of the deadline miss rate and fairness.

  • PDF

The Adequacy Analysis for Installation of High Speed Grounding Switches on the Korean 765kV Single Transmission Line

  • Ahn, Sang-Pil;Kim, Chul-Hwan;Park, Nam-Ok;Ju, Hyung-Jun;Shim, Eung-Bo
    • Journal of Electrical Engineering and Technology
    • /
    • v.1 no.4
    • /
    • pp.427-434
    • /
    • 2006
  • This paper analyzes arc phenomena including the secondary arc's elongation in the Korean 765kV single transmission line (79km) between Sin-Ansung S/S and Sin-Gapyeong S/S, which will be installed in Korea in June 2006. In particular, both frequency independent and frequency dependent line models are compared to make our final decisions. As well, the significant simulation results are investigated by the EMTP program. As a result, there is no need of HSGS in the Korean 765kV single transmission line from both a practical and an economical point of view.