• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.753-756
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• 1991

This paper aimed to analyse dose sensitivity to the controllable parameters of in-door radon $(^{222}Rn)$ and its decay products(Rn-D) by applying the input-output linear system theory. Physical behaviors of $^{222}Rn$ & Rn-D were analyzed in terms of $^{222}Rn$ gas generation, -migation and - infiltration to indoor environments, and the performance output-function(i.e. mean dose equivalent to Tracho-Bronchial(TB) lung region was assessed to the following ranges of the controllable parameters; a) the ventilation rate constant $({\lambda}_v)$ : $0{\sun}500[h^{-1}]$. b) the attachment rate constant$({\lambda}_a)$ : 0-500 $[h^{-1}]$. c) deposition rate constant $({\lambda}{_{d}^{u}})$: 0-50$[h^{-1}]$. A linear input-output model was reconstructed from the original models in literatures, as follows, which was modified into the matrices consisting of 111 nodal equations. a) indoor ${222}Rn$ & Rn-D Behaviour: jacobi- Porstendorfer- Bruno model. b) lung dosimerty : Jacobi-Eisfeld model. Some of the major findings, which identify the effectiveness of this model, were as follows. a) ${\lambda}_v$ is most effective, dominant controllable parameters in dose reduction, if mechanical ventilation is applied. b) ${\lambda}_v$, depending on the air particle-concentration, reduces the dose somewhat within ${\lambda}_v$<1 $h^{-1}R range. However, the dose increases conversely, ${\lambda}_v$>1 $h^{-1}R range range. c) ${\lambda}{_{d}^{4}}$ reduces the dose linearly as ${\lambda}_v$ dose. Such dose(z-axis) sentivities are shown with three-dimensional plots whoes x,y-axes are combined 2out the 3 parameter${\lambda}_v{\lambda}_s,\;{\lambda}_d^s$.

• The Journal of Korean Association of Computer Education
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• v.12 no.2
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• pp.77-86
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• 2009

Large-scale applications, that needs large-capacity R&D resources and realtime data transmission, have demanded more stable and high-performance network environment than current Internet environments. Recently, global R&D networks have focuses on utilizing Lambda networking technologies and resource reservation systems to be satisfied with various applications' requirements. In this paper, we modify the existing DRS (Dynamic Right-Sizing) model to reflect various advantages in terms of the stability and high-capacity of Lambda network. In addition, we suggest the design methodology of high-performance Lambda network, which can integrate NRPS (Network Resource Provisioning System) into our modified DRS model.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.245-249
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• 2013

In this paper, we propose two rate control algorithms for multi-view extension of HEVC with two rate control algorithms adopted in HEVC and analyze the multi-view rate control performance. The proposed multi-view rate controls are designed on HEVC-based multi-view video coding (MV-HEVC) platform with consideration of high-level syntax, inter-view prediction, etc. not only for the base view but also for the extended views using the rate control algorithms based on URQ (Unified Rate-Quantization) and R-lambda model adopted in HEVC. The proposed multi-view rate controls also contain view-wise target bit allocation for providing the compatibility to the base view. By allocating the target bitrates for each view, the proposed multi-view rate control based on URQ model achieved about 1.83% of average bitrate accuracy and 1.73dB of average PSNR degradation. In addition, about 2.97% of average bitrate accuracy and 0.31dB of average PSNR degradation are achieved with the proposed multi-view rate control based on R-lambda model.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.11a
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• pp.107-109
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• 2016

본 논문에서는 4K UHD 입력 영상을 실시간으로 부호화하기 위해 적용되는 GOP 단위 또는 IDR 주기 단위의 병렬 부호화 구조를 지원하도록 R-${\lambda}$ 모델 기반의 율 제어 방법을 개선하는 비트 분배(bit allocation) 방법을 제안한다. GOP 단위 또는 IDR 주기 단위의 병렬 부호화기 내에서 율 제어기를 작동시키는 경우, 계층적 B 구조에서 같은 계층에 있는 프레임 간에는 상호간에 얼마만큼의 비트를 소모 하였는지에 대한 정보를 공유 할 수 없기 때문에 기존의 비트 분배 방식으로는 비트 예산(bit budget) 관리가 불가능하다. 이를 해결하기 위해 본 논문에서는, 기존의 R-${\lambda}$ 모델 기반 율 제어 방법을 개선하여 부호화 순서에 의한 시간 순서 방향의 비트 예산 갱신 기반 비트 분배하던 방식으로부터, GOP 마다 비트를 할당한 후 계층적 B 구조에서의 계층이 깊어지는 방향으로 비트 예산을 갱신하여 비트를 분배하는 방식으로 율 배분 방식을 개선하였다. 실험 결과를 통해 R-${\lambda}$ 모델 기반 율 제어의 기존 비트 분배 방식보다 제안 방법에 의한 목표 비트 율 달성 오차가 감소함을 확인하였다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.1-7
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• 1985

Various types of shearing devices which may be a substitute for the conventional beams in stow nets were considered, and then tentatively named "the zonal canvas type of stow net" having the shearing device made of zonal canvas was devised. A 1/3 model of the net was made and experimented at sea. Converted to the full scale, the measured water resistance R(kg) of the net was given by $R=5.6{\times}10^{3}V^{l.5}$ or $R=3.5\frac{d}{l}{\lambda}_b{\lambda}_l\;V^{1.5}$, where V is the water velocity (m/sec), d the diameter of netting bars, l the length of the bars, ${\lambda}_b$ the stretched circumference of net mouth (m), ${\lambda}_l$ the length of net stretched. The net height kept about $83\%$ of the side rope length regardless of the variation of V and the net breadth kept a value over $90\%$ of the head rope length until V reached 1 m/sec. These results were very successful according to expectation, but the conventional netting was requested a further improvement. Therefore, the netting was newly designed to have smaller size of meshes in the vicinity of net mouth and larger hanging ratio breadthwise. With the netting a full scale net was made and experimented by a stern trawler. The experiment gave a net breadth over $95\%$ of the head rope length until V reached 1m/sec and showed no faults in the net. But the net operation by the stern trawler was ascribed an inconvenience to its narrow breadth of stern slip way.

• Wind and Structures
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• v.11 no.4
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• pp.275-289
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• 2008

Large eddy simulations have been performed within and over different types of urban building arrays. This paper adopted three dimensionless parameters, building frontal area density (${\lambda}_f$) the variation degree of building height (${\sigma}_h$), and the staggered degree of building range ($r_s$), to study the systematic influence of building spacing, height and layout on wind and turbulent characteristics. The following results have been achieved: (1) As ${\lambda}_f$ decrease from 0.25 to 0.18, the mean flow patterns transfer from "skimming" flow to "wake interference" flow, and as ${\lambda}_f$ decrease from 0.06 to 0.04, the mean flow patterns transfer from "wake interference" flow to "isolated roughness" flow. With increasing ${\lambda}_f$, wind velocity within arrays increases, and the vortexes in front of low buildings would break, even disappear, whereas the vortexes in front of tall buildings would strengthen and expand. Tall buildings have greater disturbance on wind than low buildings do. (2) All the wind velocity profiles and the upstream profile converge at the height of 2.5H approximately. The decay of wind velocity within the building canopy was in positive correlation with ${\lambda}_f$ and $r_s$. If the height of building arrays is variable, Macdonald's wind velocity model should be modified through introducing ${\sigma}_h$, because wind velocity decreases at the upper layers of the canopy and increases at the lower layers of the canopy. (3) The maximum of turbulence kinetic energy (TKE) always locates at 1.2 times as high as the buildings. TKE within the canopy decreases with increasing ${\lambda}_f$ and $r_s$ but the maximum of TKE are very close though ${\sigma}_h$ varies. (4) Wind velocity profile follows the logarithmic law approximately above the building canopy. The Zero-plane displacement $z_d$ heighten with increasing ${\lambda}_f$, whereas the maximum of and Roughness length $z_0$ occurs when ${\lambda}_f$ is about 0.14. $z_d$ and $z_0$ heighten linearly with ${\sigma}_h$ and $r_s$, If ${\sigma}_h$ is large enough, $z_d$ may become higher than the average height of buildings.

• Korean Journal of Metals and Materials
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• v.47 no.10
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• pp.613-620
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• 2009

The Kachanov-Rabotnov (K-R) creep model was proposed to accurately model the long-term creep curves above $10^5$ hours of Alloy 617. To this end, a series of creep data was obtained from creep tests conducted under different stress levels at $950^{\circ}C$. Using these data, the creep constants used in the K-R model and the modified K-R model were determined by a nonlinear least square fitting (NLSF) method, respectively. The K-R model yielded poor correspondence with the experimental curves, but the modified K-R model provided good agreement with the curves. Log-log plots of ${\varepsilon}^{\ast}$-stress and ${\varepsilon}^{\ast}$-time to rupture showed good linear relationships. Constants in the modified K-R model were obtained as ${\lambda}$=2.78, and $k=1.24$, and they showed behavior close to stress independency. Using these constants, long-term creep curves above $10^5$ hours obtained from short-term creep data can be modeled by implementing the modified K-R model.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.58.4-58.4
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• 2019

We present the application of the Point Spread Function (PSF) deconvolution method to the astronomical Integral Field Unit (IFU) Spectroscopy data focus on the restoration of the galaxy kinematics. We apply the Lucy-Richardson deconvolution algorithm to the 2D image at each wavelength slice. We make a set of mock IFU data which resemble the IFU observation to the model galaxies with a diverse combination of surface brightness profile, S/N, line-of-sight geometry and Line-Of-Sight Velocity Distribution (LOSVD). Using the mock IFU data, we demonstrate that the algorithm can effectively recover the stellar kinematics of the galaxy. We also show that lambda_R_e, the proxy of the spin parameter can be correctly measured from the deconvolved IFU data. Implementation of the algorithm to the actual SDSS-IV MaNGA IFU survey data exhibits the noticeable difference on the 2D LOSVD, geometry, lambda_R_e. The algorithm can be applied to any other regular-grid IFS data to extract the PSF-deconvolved spatial information.

• Journal of Broadcast Engineering
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• v.22 no.2
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• pp.193-206
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• 2017

In this paper, we propose a rate control method based on the $R-{\lambda}$ model that supports a parallel encoding structure in GOP levels or IDR period levels for 4K UHD input video in real-time. For this, a slice-level bit allocation method is proposed for parallel encoding instead of sequential encoding. When a rate control algorithm is applied in the GOP level or IDR period level parallelism, the information of how many bits are consumed cannot be shared among the frames belonging to a same frame level except the lowest frame level of the hierarchical B structure. Therefore, it is impossible to manage the bit budget with the existing bit allocation method. In order to solve this problem, we improve the bit allocation procedure of the conventional ones that allocate target bits sequentially according to the encoding order. That is, the proposed bit allocation strategy is to assign the target bits in GOPs first, then to distribute the assigned target bits from the lowest depth level to the highest depth level of the HEVC hierarchical B structure within each GOP. In addition, we proposed a processing method that is used to improve subjective image qualities by allocating the bits according to the coding complexities of the frames. Experimental results show that the proposed bit allocation method works well for frame-level parallel HEVC software encoders and it is confirmed that the performance of our rate controller can be improved with a more elaborate bit allocation strategy by using the preprocessing results.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.3
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• pp.149-153
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• 2022

The degree distribution of the plant-pollinator network was identified by analyzing the data in the ecosystem and reproduced by a model of the growing bipartite mutualistic networks. The degree distribution of pollinator shows power law or stretched exponential distribution, while plant usually shows stretched exponential distribution. In the growth model, the plant and the pollinator are selected with probability P_p and P_A=1-P_p, respectively. The number of incoming links for the plant and the pollinator is l_p and l_A, respectively. The probability that the link of the plant selects the pollinator of the existing network given as $A_{k_i}=k^{{\lambda}_A}_i/{\sum}_i\;k^{{\lambda}_A}_i$, and the probability that the pollinator selects the plant is $P_{k_i}=k^{{\lambda}_p}_i/{\sum}_i\;k^{{\lambda}_p}_i$. When the nonlinear growth index is 𝛌_X=1 (X=A or P), the degree distribution follows a power law, and if 0≤𝛌_X<1, the degree distribution follows a stretched exponential distribution. The cumulative degree distributions of plants and pollinators of 14 empirical plant-pollinators included in Interaction Web Database were calculated. A set of parameters (P_A,P_P,l_A,l_P) that reproduces these cumulative degree distributions and a growth index 𝛌_X (X=A or P) were obtained. We found that animal takes very heterogenous connections, whereas plant takes a more flexible connection network.