• Journal of KIISE:Computing Practices and Letters
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• v.10 no.4
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• pp.309-318
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• 2004

This paper proposes the H.264-based selective fine granular scalable (FGS) coding scheme that selectively uses the temporal prediction data in the enhancement layer. The base layer of the proposed scheme is basically coded by the H.264 (MPEG-4 Part 10 AVC) visual coding scheme that is the state-of-art in codig efficiency. The enhancement layer is basically coded by the same bitplane-based algorithm of the MPEG-4 (Part 2) fine granular scalable coding scheme. In this paper, we introduce a new algorithm that uses the temproal prediction mechanism inside the enhancement layer and the effective selection mechanism to decide whether the temporally-predicted data would be sent to the decoder or not. Whenever applying the temporal prediction inside the enhancement layer, the temporal redundancies may be effectively reduced, however the drift problem would be severly occurred especially at the low bitrate transmission, due to the mismatch bewteen the encoder's and decoder's reference frame images. Proposed algorithm selectively uses the temporal-prediction data inside the enhancement layer only in case those data could siginificantly reduce the temporal redundancies, to minimize the drift error and thus to improve the overall coding efficiency. Simulation results, based on several test image sequences, show that the proposed scheme has 1∼3 dB higher coding efficiency than the H.264-based FGS coding scheme, even 3∼5 dB higher coding efficiency than the MPEG-4 FGS international standard.

• Journal of Broadcast Engineering
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• v.28 no.3
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• pp.314-328
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• 2023

In this paper, we propose a texture map compression method based on the hierarchical coding method of SHVC to support the scalability function of dynamic mesh compression. The proposed method effectively eliminates the redundancy of multiple-resolution texture maps by downsampling a high-resolution texture map to generate multiple-resolution texture maps and encoding them with SHVC. The dynamic mesh decoder supports the scalability of mesh data by decoding a texture map having an appropriate resolution according to receiver performance and network environment. To evaluate the performance of the proposed method, the proposed method is applied to V-DMC (Video-based Dynamic Mesh Coding) reference software, TMMv1.0, and the performance of the scalable encoder/decoder proposed in this paper and TMMv1.0-based simulcast method is compared. As a result of experiments, the proposed method effectively improves in performance the average of -7.7% and -5.7% in terms of point cloud-based BD-rate (Luma PSNR) in AI and LD conditions compared to the simulcast method, confirming that it is possible to effectively support the texture map scalability of dynamic mesh data through the proposed method.

• Spatial Information Research
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• v.11 no.3
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• pp.301-325
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• 2003

Urban residential area, one of the main subjects of urban and architectural studies, can be analyzed accurately and rapidly with CIS. (Geographic Information System) And the applications of GIS in urban studies are too macro to be explained in architectural terms and the ones in architectural studies are not so much active rather be used as a secondary means. So the studies in urban-architectural scale are very useful in many ways. This study explores urban-architectural possibilities of analytic capabilities of GIS through the analysis of spatial characteristics of residential area in terms of land price according to parcel attributes. It is found, firstly, that the parcel attributes have relations with land price and its distribution patterns. Secondly, it is verified that the visualization capability of GIS can be a very useful method of analysis through user-interface effects in urban-architectural scaled analysis.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1378_1380
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• 2009

절연파괴 강도에대한 특성분석을 위해 와이블 plot을 이용하였다. ENMMC에서 실란처리와 미처리특성에서 실란처리된 결과 형상파라미터가 상대적으로 높은 값을 나타내었다. 이는 절연파괴결과가 균질함을 분명하게 나타낸 결과이다. 또한 스케일파리미터에서도 처리된 결과가 상대적으로 높은 결과를 보이고 있다. 나노입자 충진함량에 대한 효과에서도 체적비로 6.2vol%가 24.87vol%보다 월등하게 높은 형상파리미터와 스케일 파리미터를 나타내었다. 현장에서는 B10의 수명이 누적확률(63.2%)보다 오히려 유효한 평가자료 라고 사료된다. 역시 실란처리 된 결과가 미처리된 것에 비하여 그리고 나노입자 충진함량이 적을수록 높은 결과를 나타내었다. 이로서 중전기기 산업절연재료로서 향후 전망을 크게 할 것으로 본다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.315-321
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• 2012

In this study, a sequential multiscale homogenization method to characterize the effective thermal conductivity of nano particulate polymer nanocomposites is proposed through a molecular dynamics(MD) simulations and a finite element-based homogenization method. The thermal conductivity of the nanocomposites embedding different-sized nanoparticles at a fixed volume fraction of 5.8% are obtained from MD simulations. Due to the Kapitza thermal resistance, the thermal conductivity of the nanocomposites decreases as the size of the embedded nanoparticle decreases. In order to describe the nanoparticle size effect using the homogenization method with accuracy, the Kapitza interface in which the temperature discontinuity condition appears and the effective interphase zone formed by highly densified matrix polymer are modeled as independent phases that constitutes the nanocomposites microstructure, thus, the overall nanocomposites domain is modeled as a four-phase structure consists of the nanoparticle, Kapitza interface, effective interphase, and polymer matrix. The thermal conductivity of the effective interphase is inversely predicted from the thermal conductivity of the nanocomposites through the multiscale homogenization method, then, exponentially fitted to a function of the particle radius. Using the multiscale homogenization method, the thermal conductivities of the nanocomposites at various particle radii and volume fractions are obtained, and parametric studies are conducted to examine the effect of the effective interphase on the overall thermal conductivity of the nanocomposites.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.1
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• pp.94-101
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• 2009

This paper presents scalable modeling of spiral inductors for RFIC design based on $0.13{\mu}m$ RF CMOS process. For scalable modeling, several inductor patterns are designed and fabricated with variations of width, number of turns and inner radius. Feeding structures are optimized for accurate de-embedding of pad effects. After measuring the S parameters of the fabricated patterns, double-$\pi$ equivalent circuit parameters are extracted for each device and their geometrical dependences are modeled as scalable functions. The inductor library provides two types of models including standard and symmetric inductors. Standard and symmetric inductors have the range of $0.12{\sim}10.7nH$ and $0.08{\sim}13.6nH$ respectively. The models are valid up to 30GHz or self-resonance frequency. Through this research, a scalable inductor library with an error rate below 10% is developed for $0.13{\mu}m$ RF CMOS process.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6C
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• pp.267-274
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• 2012

The conventional approach to evaluate the contaminant transport in soils adopts the macro-scale implementation while the pore configuration and network is a dominant factor to determine the fate of contaminant. However, the observation of fate and transport at pore scale may not be readily approachable because of the computational expenses to solve Navier-Stokes equation. We herein present the 2D Lattice-Boltzmann method that enables to assess the local fluid velocity and density efficiently for the case of single phase and multi-components. The solute fate spatio-temperal space is explicitly determined by the advection of fluid flow. Two different types of idealized pore space provides the path of fluid. Also, solute transport, the velocity field and average concentration of solute are computed in steady state. Results show that the pore geometry such as tortuosity mainly affect the solute fate. It highlights the significance of the pore configuration and shape in granular soils and rock discontinuity in spite of the equivalent porosity.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.7
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• pp.768-774
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• 2010

Reconstruction of implicit surfaces from scattered point data sets have been developed in various engineering and scientific studies. In this paper, we represent a method to construct functions of 2D point data using multi-scale kernels and show it can be applied to graphics applications needed to access data in real-time. Our approach is similar to previous work in that a set of coefficients of the functions are calculated and stored in the preprocessing stage and function values at arbitrary positions are evaluated for real-time applications, however, it is different from others in that users can choose detail levels freely in real-time processing stage. The reason why the functions implicitly supports multi-resolution results from the mathematical properties of multi-scale kernels, and proposed method can be expanded to represent multi-resolution functions of n-dimensional data.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.37-45
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• 2015

Prediction of combustion instability within a solid-propellant rocket motor has been conducted with the classical acoustic analysis. The effect of particle size distribution on the instability has been analyzed by comparing the log-normal distribution to the fixed mono-sized particle followed by a survey of motor length scale effect between the baseline model and small scale model. Particle damping effect was more efficient for the small scale motor which has a relatively high unstable mode frequencies. It was also revealed that the prediction results by considering the particle size distribution show an overall attenuation of fluctuating pressure amplitude with respect to the mono-sized case.

• Journal of the Korean Geographical Society
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• v.46 no.2
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• pp.197-211
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• 2011

Due to the complexity of spatial interaction and the necessity of spatial representation and modeling, aggregation of spatial interaction data is indispensible. Given this, the purpose of this paper is to evaluate the effects of modifiable areal unit problem (MAUP) on a spatial interaction model. Four aggregation schemes are utilized at eight different scales: 1) randomly select seeds of district and then allocate basic spatial units to them, 2) minimize the sum of population weighted distance within a district, 3) maximize the proportion of flow within a district, and 4) minimize the proportion of flow within a district. A simple Poisson regression model with origin and destination constraints is utilized. Analysis results demonstrate that spatial characteristics of residuals, parameter values, and goodness-of-fit of the model were influenced by aggregation scale and schemes. Overall, the model responded more sensitively to aggregation scale than aggregation schemes and the scale effect on the model was varied according to aggregation schemes.