• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2010년도 하계학술대회
• /
• pp.112-115
• /
• 2010

본 논문은 그림 1과 같은 네트워크 환경에서 두 송신단이 LT code를 오류정정 부호로 사용할 때, 두 송신단이 생성하는 인코딩 심볼과 수신단이 수신하는 인코딩 심볼들의 degree distribution의 관계에 대해 다룬다. LT code를 복호하기 위해 belief propagation 방법을 사용했을 때, 수신단이 받은 인코딩 심볼들의 degree distribution은 robust soliton distribution(RSD)을 따를 때, overhead 대비 가장 높은 확률로 복호에 성공한다. 하지만 그림 1과 같은 네트워크 환경에서, 두 송신단 모두 RSD에 따라 인코딩 심볼을 생성하여 송신하면, 수신단에서 수신한 심볼은 RSD를 따르지 않는다. 본 논문은 한 송신단($S_1$) 이 생성하는 인코딩 심볼의 degree distribution을 알 때, 수신단에서의 인코딩 심볼의 분포가 근사적으로 RSD를 따르도록 하는 또 다른 송신단($S_2$)에서의 degree distribution을 구하는 방법을 제시한다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권8호
• /
• pp.3630-3656
• /
• 2018

Degree distribution can provide basic information for structural characteristics and internal relationship in social network. It is a critical procedure for social network topology analysis. In this paper, based on the mean-field theory, we study a special type of social network with exponential distribution of time intervals. First of all, in order to improve the accuracy of analysis, we propose a spreading coefficient algorithm based on intimate relationship, which determines the number of the joined members through the intimacy among members. Then, simulation show that the degree distribution of follows the power-law distribution and has small-world characteristics. Finally, we compare the performance of our algorithm with the existing algorithms, and find that our algorithm improves the accuracy of degree distribution as well as reducing the time complexity significantly, which can complete 29.04% higher precision and 40.94% lower implementation time.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• 제3권3호
• /
• pp.149-153
• /
• 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.

• 통상정보연구
• /
• 제14권2호
• /
• pp.3-27
• /
• 2012

중국의 정치적, 경제적 위상이 급등함에 따라 더욱 더 많은 다국적기업들이 중국 시장을 공략하기 위해 진줄 기회를 엿보고 있다. 특히 한국은 중국과 지리적으로 인접해 있으나 중국시장에 안착하지 못하는 안타까운 사례가 많다. 이에 본 연구는 중국에 진출해 있는 한국 제조 기업들을 대상으로 유통현지적응 정도를 조사하고, 이러한 현지적응에 미치는 영향요인을 문헌 연구를 통해 도출하였다. 146부의 설문지를 분석한 결과 기존의 연구들과는 달리 중국의 유통 환경적인 요인 중에서 유통경로의 길이가 유통 현지적응 정도에 긍정적인 영향을 미치는 것으로 나타났다. 게다가 기업의 전략적 자산 중에서도 유통 관계자산이 유통 현지적응 정도와 정(+)의 관계가 있음이 밝혀졌다. 이러한 결과를 통해 최근 중국 유통시장이 후진국의 수준을 벗어나 세계적인 수준으로 발돋움하고 있음을 알고 중국 시장 진출 기업은 과소평가 하지 않도록 유의해야 할 것이다.

• Journal of Electrochemical Science and Technology
• /
• 제15권1호
• /
• pp.132-151
• /
• 2024

Proton exchange membrane fuel cell (PEMFC) has received extensive attention as it is the most common hydrogen energy utilization device. This research not only investigated the effect of obstacle number and shape on PEMFC performance, but also studied the effect of the blockage degree in the channel of PEMFC on its performance. It was found that compared with traditional scheme, longitudinally distributed obstacles scheme can significantly promote reactants transfer to catalyst layer, and the blockage degree in the channel effect PEMFC performance most. The scheme with 10 rectangular obstacles in single channel and 60% channel blockage had the best output performance and the most uniform distribution of reactants and products. Obstacle height distribution can significantly affect PEMFC performance, the blockage degree in the whole basin was large, particularly as the channel was blocked to higher degree in region 2 and region 3, higher net power density and better mass transfer effect can be obtained. Among them, the fuel cell with the blockage degree of 40%, 60% and 60% in region 1, region 2 and region 3 have the best PEMFC output performance and mass transfer, the net power density was 29.8% higher than that of traditional scheme.

• 한국공간정보시스템학회 논문지
• /
• 제11권2호
• /
• pp.13-18
• /
• 2009

This paper presents the implementation procedure of encoding and decoding algorithms for Tornado code that can provide fault tolerance for storage and transmission system. The degree distribution satisfying heavy tail distribution is produced. Based on this distribution, a good random irregular bipartite graph is attained after plenty of trails. Such graph construction is proved to be efficient, and the experiments also demonstrate that the implementation obtains good performance in terms of decoding overhead.

• Architectural research
• /
• 제14권4호
• /
• pp.153-161
• /
• 2012

This paper presents an integrated procedure to predict the temperature and moisture distributions in hardening concrete considering the effects of temperature and aging. The degree of hydration is employed as a fundamental parameter to evaluate hydro-thermal-mechanical properties of hardening concrete. The temperature history and temperature distribution in hardening concrete is evaluated by combining cement hydration model with three-dimensional finite element thermal analysis. On the other hand, the influences of both self-desiccation and moisture diffusion on variation of relative humidity are considered. The self-desiccation is evaluated by using a semi-empirical expression with desorption isotherm and degree of hydration. The moisture diffusivity is expressed as a function of degree of hydration and current relative humidity. The proposed procedure is verified with experimental results and can be used to evaluate the early-age crack of hardening concrete.

• 한국수학교육학회지시리즈A:수학교육
• /
• 제39권2호
• /
• pp.167-177
• /
• 2000

In this thesis we concerned with the degree of similarity in pairs of scores having a common mean and variance could express similarity in terms of the absolute difference between the standardized scores. We particulary discussed the distribution of absolute differences between pairs of T scores among many standardized scores and demonstrated the procedures for calculating the lower limit of Med(│d│) values i. e. the maximum possible similarity with medians and correlation coefficients of the equivalent form tests by using the folded normal distribution, although other researchers expressed the degree of similarity using only the standard normal distribution. We also described many cases how to use those techniques and to apply effectively them in real evaluation fields.

• 디지털산업정보학회논문지
• /
• 제10권4호
• /
• pp.117-125
• /
• 2014

In this paper, a novel hardware architecture of the LT codec is presented where non-BP based decoding algorithm is applied. Novel LT codec architecture is designed with an efficient degree distribution unit using Verilog HDL. To perform permutation operation, different initial valued or time shifted counters have been used to get pretty well permutations and an effect of randomness. The codec will take 128 bits as input and produce 256 encoded output bits. The simulation results show expected performances as the implemented distribution and the original distribution are pretty same. The proposed LT codec takes 257.5 cycle counts and $2.575{\mu}s$ for encoding and decoding instead of 5,204,861 minimum cycle counts and 4.43s of the design mentioned in the previous works where iterative soft BP decoding was used in ASIC and ASIP implementation of the LT codec.

• Ocean and Polar Research
• /
• 제39권2호
• /
• pp.73-84
• /
• 2017

The probability distribution of ichthyoplankton is important for enhancing the precision of sampling while reducing unnecessary surveys. To estimate the ichthyoplankton detection proportion (IDP) and its margin of error (ME), the monitoring information of the chub mackerel's (Scomber japonicus) ichthyoplankton presence-absence sampling data has been were collected over approximately 30 years (from 1982 to 2011) in the Korean coastal seas. Based on the computed spatial distributions of the mackerel's IDP and ME, the confidence interval (CI) range, defined as 2 ME, decreases from approximately 80% to 40% as the sample size n increases from 4 to 24 and the ME is approximately 40% in the typical (seasonal survey) case n = 4 per year. The IDP and ME off Jeju Island are relatively high at the 0.5-degree smoothing level. After increasing the spatial smoothing level to 1.0-degree, the ME decreased, and the spatial distribution pattern also changed due to the over-smoothing effects. In this study, the 0.5-degree smoothing is more suitable for the distribution pattern than the 1.0-degree smoothing level. The area of the high IDP and the low ME on the mackerel's ichthyoplankton was similar to the estimated spawning ground in the Korean peninsula. This information could contribute to enhancing for the spawning ecology surveys.