• 한국구조물진단유지관리공학회 논문집
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• 제26권2호
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• pp.18-27
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• 2022

본 연구에서는 해양 폭로 조건과 배합 사항을 고려하여 GGBFS 콘크리트의 시간의존적 염화물 확산 거동을 분석하였다. 사용 콘크리트 배합은 3 수준의 물-결합재 비 및 고로슬래그 미분말 치환률을 고려한 콘크리트 배합이며 노출 조건으로는 침지대, 간만대, 비말대 총 3 수준을 고려하여 옥외 폭로 시험을 수행하였다. 겉보기 염화물 확산계수 평가 결과, 고로슬래그 미분말의 치환률이 증가할수록 노출 기간 730일(2년)을 기준으로 평가한 확산계수의 감소율이 감소하였다. 또한 노출 조건에 따른 확산거동을 평가한 결과, 침지대, 간만대, 비말대 순으로 확산계수가 평가되었다. 비말대에서는 해수의 건습 반복으로 인해 비교적 높은 확산계수가 평가되었다. 본 연구에서는 고로슬래그 미분말 치환률이 겉보기 염화물 확산계수 감소 거동에 미치는 영향을 노출 조건 및 기간을 고려하여 분석하였다. 확산계수를 출력 값으로, 고로슬래그를 입력 값으로 설정한 선형 회귀분석을 수행하였으며, 노출 기간 730일 이후 고로슬래그 미분말이 확산계수에 미치는 영향이 크게 감소하였다. OPC 콘크리트라 할지라도 730일 이후 GGBFS 콘크리트 만큼 낮은 확산계수를 나타냈기 때문이며 고로슬래그 미분말의 사용을 통해 730일 이전에 뛰어난 초기 염해 내구성능 확보가 가능하다고 사료된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(2)
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• pp.932-933
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• 2005

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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• pp.181-186
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• 1994

The steel in concrete structures under the environment of seawater easily corrode as the seawater penetrate into concrete. The purpose of this study is to analysis the properties of chloride diffusion in mortar using mineral admixtures, as a part of study to examine the chloride penetration of concrete. The results show that the chloride diffusion in mortar increased with higher water-cement ratio. In the case of mortar using mineral admixtures the scope of diffusion coefficient$(\times10^{-8}cm^2/sec)$increased SF20(0.9), SG60(3.3), FA20(3.9), and OC(6.1) in order at the same water-cement ratio 50%.

• Journal of applied mathematics & informatics
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• 제31권5_6호
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• pp.695-709
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• 2013

Calcium is well known role for signal transduction in a neuron cell. Various processes and parameters modulate the intracellular calcium signaling process. A number of experimental and theoretical attempts are reported in the literature for study of calcium signaling in neuron cells. But still the role of various processes, components and parameters involved in calcium signaling is still not well understood. In this paper an attempt has been made to develop two dimensional finite element model to study calcium diffusion in neuron cells. The JRyR, JSERCA and JLeak, the exogenous buffers like EGTA and BAPTA, and diffusion coefficients have been incorporated in the model. Appropriate boundary conditions have been framed. Triangular ring elements have been employed to discretized the region. The effect of these parameters on calcium diffusion has been studied with the help of numerical results.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2008년도 추계학술대회 및 정기총회
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• pp.329-341
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• 2008

Knowledge management has garnered attention due to its role of maintaining competitive advantage. Creating and sharing knowledge is an essential part of managing knowledge. However, the best knowledge is underutilized because employees tend to seek knowledge through their informal networks, not reach out to other sources for obtaining the best knowledge. Prior studies on informal networks pointed out a negative influence of heavy reliance on learning through informal networks but they paid little attention to a structure of informal networks and its impacts on diffusion of knowledge. The aim of our study is to show impacts of informal network on knowledge management by employing a network structure and investigating diffusion of knowledge within it. Our study found out that performance of learning becomes lower in a highly clustered network. Creating random links such as serendipitous learning can improve performance of knowledge management. When employees rely on a knowledge management system, creating random links is not necessary. Costs of adopting knowledge affect performance of knowledge management.

• 복식
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• 제63권2호
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• pp.1-13
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• 2013

The purpose of this study is to examine how the features of network in the Internet fashion community affect the diffusion of fashion information to members in the online community with other variables (informative features, consumer features). Communities that actively exchange fashion information among their members were selected for the social network analysis and hypothesis verification. As a result, we found that a few information activists influenced most of the information receivers in the network features of fashion communities. Also, we found that the informative features (usefulness, reliability), consumer features (NFC, innovation) as well as the network features (connectivity, power), have a significant influence on the diffusion of Internet fashion information which verified the importance of the network features in the study on the Internet.

• 한국IT서비스학회지
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• 제11권1호
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• pp.305-323
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• 2012

This study examines online social media diffusion across different countries that will help to provide a picture of current global online social network services (SNSs). Analyzing country-level data drawn from 78 nations, we find that non-technological factors such as culture and language as well as technological factors including Internet penetration rate and smartphone adoption rate have significant effects on online social media diffusion. These findings, derived from a broad range of different countries, not only provide theoretical insights into understanding critical factors that enable successful global expansion of online social media services but also help practitioners plan their marketing strategies more effectively in a global context.

• Journal of Korean Neurosurgical Society
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• 제41권6호
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• pp.371-376
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• 2007

Objective : The aim of this study was to investigate the usefulness of diffusion-weighted imaging [DWI] and apparent diffusion coefficiency [ADC] in distinguishing brain abscesses from cystic or necrotic brain tumors, which are difficult to be differentiated by conventional magnetic resonance imaging techniques. Methods : Seven patients with brain abscesses and ten patients with cystic brain tumors were studied from September 2003 to October 2005. Abscess, subdural empyema and ventriculitis were categorized to the abscess group and cystic or necrotic brain gliomas or metastatic brain tumors into the tumor group. Preoperative magnetic resonance images were performed in all patients and diffusion-weighted images and apparent diffusion coefficiency values of lesions were calculated directly from software of 1.5 tesla MRI [General Electrics, USA]. The ratio of the ADC of the lesion to contralateral regional ADC was also measured [relative ADC, rADC]. Results : The average ADC value of pyogenic abscesses group was $0.82+/-0.14{\times}10^{-3}\;[mean+/-S.D.]\;mm^2/s$ and mean rADC was 0.75. Cystic or necrotic areas had high ADC values [$2.49+/-0.79{\times}10^{-3}\;mm^2/s$, mean rADC=2.14]. ADC and rADC values of abscesses group showed about three times lower values than those of cystic or necrotic tumor group. Conclusion : This study results based on numerical comparison of signal intensities and quantitative analysis to distinguish between brain abscess and cystic or necrotic tumor, DWI and ADC mapping are thought to be very useful diagnostic tools.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.747-750
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• 1999

Chloride ions are considered to be the major cause of steel corrosion in concrete structures exposed to seashore environments. Thus, estimating chloride ion concentrations by ages is needed to predict service life of seashore structures. Experimentally measured chloride profiles were used in this study for estimating chloride diffusion coefficients, and a relationship between mixing properties and chloride diffusion coefficients is proposed for predicting chloride penetrations.

• 대한수학회지
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• 제47권6호
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• pp.1137-1146
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• 2010

In this paper, we study the divergence based goodness of fit test for partially observed sample from diffusion processes. In order to derive the limiting distribution of the test, we study the asymptotic behavior of the residual empirical process based on the observed sample. It is shown that the residual empirical process converges weakly to a Brownian bridge and the associated phi-divergence test has a chi-square limiting null distribution.