• Journal of information and communication convergence engineering
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• 제5권4호
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• pp.339-345
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• 2007

Video transcoding is a technique used to convert a compressed input video stream with an arbitrary format, size, and bitrate into a different attribute video stream different attributes to provide a efficient video streaming service for the customers is dispersed in the heterogeneous networks. Specifically, frames deletion occur in a transcoding scheme that exploits the adjustment of frame rate, and at this time, the loss in temporal relation among frames due to frame deletion is compensated for the prediction of motion estimation by reusing motion vectors in the would-be deleted frames. But the processing time for transcoding don't have an improvement as much as our expectation because transcoding is done only within the transcoder. So in this paper, we propose a new transcoding algorithm based on prediction period to improve transcoding-related processing time. For this, we also modify the existing encoder so as to adjust dynamically frame rate based on the prediction period and deletion period of frames. To check how the proposed algorithm works nicely, we implement a video streaming system with the new transcoder and encoder to which it is applied. The result of the performance test shows that the streaming system with proposed algorithm improve 60% above in processing time and also PSNR have a good performance while the quality of pictures is preserved.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.269-282
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• 2005

We study the global asymptotic stability, global attractivity, boundedness character, and periodic nature of all positive solutions and all negative solutions of the difference equation $$x_{n+1}\;=\;{\alpha}-{\frac{x_{n-1}}{x_{n}},\;n=0,1,\;{\cdots}$$, where ${\alpha}\;\in\; R$ is a real number, and the initial conditions $x_{-1},\;x_0$ are arbitrary real numbers.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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• pp.464-467
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• 2001

A good arithmetic random number generator should possess full period, uniformity and independence, etc. To obtain the excellent random number generator, many researchers have found good parameters. Also an initial seed is the important factor in random number generator. But, there is no theoretical guideline for using the initial seeds. Therefore, random number generator is usually used with the arbitrary initial seed. Through the empirical tests, we show that the choice of the initial values for the seed is important to generate good random numbers.

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 광학 및 양자전자학 워크샵
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• pp.123-132
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• 1990

The method of characteristic matrix used in the calculation of multi-layered optical coating is applied to the analysis of DFB waveguide with arbitrary structure of grating by plecewise approximation where the DFB structure is devided into many sections in which the gain and period, amplitude and phase of DFB structure are assuced to be constant in each section. The DFB structure with two section is analyzed using this method of C-matrix. The possible applications for photonic devices using DFB waveguides are proposed.

• Korean Journal of Mathematics
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• 제14권1호
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• pp.85-93
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• 2006

A good arithmetic random number generator should possess full period, uniformity and independence, etc. To obtain the excellent random number generator, many researchers have found good parameters. Also an initial seed is the important factor in random number generator. But, there is no theoretical guideline for using the initial seeds. Therefore, random number generator is usually used with the arbitrary initial seed. Through the empirical tests, we show that the choice of the initial values for the seed is important to generate good random numbers.

• Journal of the Optical Society of Korea
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• 제3권2호
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• pp.55-63
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• 1999

For the precise analysis and design of LPFG's, a new method of generalized N$\times$N coupled-mode theory by section-wise discretization was proposed. This is applicable to the analysis for arbitrary grating structures, which can readily take grating nonuniformities and multimode couplings into account. Utilizing the method, several analyses of LPFG's were presented, and relationships between the grating structures and their spectral responses were discussed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.375-378
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• 1998

Scattering of TE waves by a periodic conducting surface with dielectric cover is considered. A method for the aalysis of scattering from periodic structures based on the numerical solution of the integral equations is further developed. Using periodicity (Floquet's theorem), the range of the integral equations is reduced to a single period where the kernels are the Green's functions for periodic arrays. The numerical solution of the intergral equations is obtained using the method of moments. From numerical results for the reflected power the effects of surface profile shape, period-to-depth ratio, and cover permittivity on the scattering behaviors are examined.

• 건축역사연구
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• 제24권2호
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• pp.7-16
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• 2015

This article deals with a proportional analysis of Cologne Cathedral with regard to the medieval tradition of geometry and figurate numbers that were commonly used in the medieval period. It first outlines symbolic and geometric notions of the geometry and numbers during the medieval period, and then, interprets the proportional design of the plan and section of the cathedral in analogy with the notion. It concludes that the proportional design of the cathedral was not quite arbitrary but carefully designed for the systematic and symbolic quality of the medieval aesthetic tradition.

• 한국대기환경학회지
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• 제21권3호
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• pp.285-293
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• 2005

This study was aimed at estimation of gas-particle partitioning of polychlorinated biphenyls (PCBs) in ambient air. The samples were collected at urban site in Japan from March 2002 to January 2003. The concentration of total PCBs (from 4 CB to 10 CB) and TEQ (Toxic equivalent) ranged from 62 to $247\;pg/m^3$ and from 2 to $14\;fgTEQ/m^3 $, respectively. The average contribution $(\%)$ of gas phase to total PCBs concentration was above $80\%$, which suggests that in the atmosphere PCBs predominantly existed in the gas phase. The weak correlations between total PCBs concentration and temperature was found. However this result was due to a typhoon during summer and raining during sampling period. The gas-particle partition coefficient (Kp) was obtained as a function of temperature. The partition ratio of gaseous and particulate phase PCBs can be estimated for an arbitrary temperature. The plot of gas/particle partition coefficient (log Kp) vs. sub-cooled liquid vapor pressure $(log\;P_L)$ had reasonable correlations for individual samples but the slope varied among the samples (coefficients of determination for log Kp versus log $P_L$ plot were> 0.76 $(p<0.0001)$, except for 3 samples). As a result, the variations in the slope among the sampling period may be due to change of temperature, raining during sampling period and wind in this study.

• 한국수자원학회논문집
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• 제35권1호
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• pp.13-24
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• 2002

본 연구에서는 역학적으로 실질적이면서도 단순화된 방법으로 폭풍과 같은 악후시에 임의의 해안단면에서 발생하는 소상파의 수동학적 거동에 대한 예측모델을 개발하고자 한다. 실제 크기의 폭풍과 조건하에서 사구의 침식을 모의하기 위해 수행된 대형조파수조 실험에서 계측된 실험자료가 모델 개발을 위해서 활용된다. 일반적으로 본 모델은 해안종단방향에서의 소상파의 파고, 속도 및 주기의 변화를 예측할수 있음을 보인다. 정량적으로 보다 나은 소상파 변수들에 대한 예측은 유의 소상파고가 영이 되는 해빈면의 높이, ymax에 대한 예측향상을 통하여 이루어질수 있다.