• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.708-717
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• 2002

Durability is a major concern in the design and construction of concrete structures which are located in the sea environments. In particular, the combined action of chlorides, sulfates, and carbonation nay influence greatly the deterioration behavior of concrete structures. The purpose of the present study is to explore the diffusion characteristics of chloride ions in concrete structures under combined deterioration conditions. The present test results indicate that the chloride penetration into concrete structures is more pronounced under combined attacks of chlorides, sulfates and carbonation. The diffusion coefficients and surface chloride contents were found to increase under combined multiple deterioration conditions. The present study provides quantitatively the penetration and diffusion characteristics of chloride ions in concrete structures under various deterioration conditions. The results of present study may be efficiently used for the realistic design of concrete structures under combined deterioration conditions.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2001.11a
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• pp.19-35
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• 2001

우리나라에서 수행된 국책연구개발기술과 관련된 기존 연구는 주로 기술개발에 초점이 맞추어진 관계로, 개발기술의 상용화는 연구개발 결과평가요인의 하나로서 다루어졌을 뿐, 그 자체를 효율화하기 위한 체계적인 연구는 없었다고 해도 과언이 아니다. 이러한 결과로 실제 국책연구개발의 기술적인 이전이 부족하고, 여러 분야에로의 2차 확산을 통한 상용화에 대한 성공률이 상대적으로 낮은 수준에 머무르고 있다. 또한 국내에서 출원된 특허를 포함한 산업재산권의 휴면 율이 55%-65% 수준에 이르고 있다. 이와 같이 연구개발기술의 산업계로의 확산이 부족한 관계로 국제적인 기술경쟁력의 제고가 어려우며, 기술발전과 산업발전이 상호 작용하는 선 순환적 구조를 이루지 못하고 있다. 따라서 본고에서는 기술집약형 중소기업 또는 기술벤처기업을 통한 정보통신산업분야의 정부지원 연구개발 기술의 상업화를 촉진하기 위한 효율적 방안의 도출을 위하여, 일차적으로 연구개발 기술의 상용화프로세스 모형을 도출하고, 다음으로 도출된 모형의 단계별 특성에 대한 기술개발자, 기술사용기업, 지원기관간의 중요도 차이를 분석하고자 한다. 이를 위하여 기존의 기술상용화 관련문헌 분석과, 우리나라의 정보통신 분야의 상용화 특성분석을 통하여, 우리나라 기술개발특성에 맞는 6 단계의 상용화프로세스 모형, 즉 1) 연구개발 계획 및 제안서 작성, 2)연구개발의 수행, 3)개발기술의 인큐베이팅과 시작품제작, 4)테스팅, 엔지니어링 및 시험생산, 5) 공장입지 결정 및 대량생산, 6) 시장판매, 마케팅 및 확산 등을 도출하였다. 아울러 동 모형의 단계별 특성을 설문지로 작성하여, 기술사용기업(벤처기업 및 기술집약형 중소기업), 기술개발자(국책연구소, 대학, 및 일반기업), 관련기관(정부, TBI운영기관, 정책 및 지원기관)을 대상으로 설문조사를 하였다. 회수 및 사용된 142개 설문지 분석을 통하여, 일차적으로 정보통신 국책개발기술의 상용화에 관한 변수들의 중요도 순위로 본 중요도 실태를 분석하였으며, 나아가 이들 변수에 대하여 앞에서 제시한 기술사용기업-기술개발자-관련기관 즉 세 집단 간의 차이분석 즉 ANOVA 분석을 하였다. 이러한 분석을 통하여 우리나라 정보통신 국책연구개발기술의 상용화와 관련된 특성을 도출하는 동시에, 이를 촉진하기 위한 인프라조성과 관련한 중요한 특성 및 지원정책 대안을 도출하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.807-815
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• 2013

A numerical study on soot formation in a laminar ethylene diffusion flame at atmospheric pressure was conducted to obtain a better understanding of the effects of buoyancy on sooting flames under 0g and 1g using a gas-phase reaction mechanism and thermal and transport properties. A simple model was employed to predict soot formation, growth and oxidation with interactions between the gas phase chemistry and the soot chemistry taken into account. Results showed that the flames in 0g are much wider than that of 1g because of the thicker diffusion layer and reduction in axial velocity. The reduction in the axial velocity in 0g results in longer residence times, and resulting in greatly enhanced soot volume fraction. And, under zero-gravity, due to the lack of a buoyancy-induced instability, flame instability disappears.

• The Journal of the Korea Contents Association
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• v.15 no.2
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• pp.444-454
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• 2015

The purpose of this study is to investigate factors related to use-diffusion of Nscreen service as well as consumers' lifestyle and media usage of Nscreen service, which is fundamentally changing both the competitive landscape for business and the daily lives of consumers. The data of 1,524 consumers used in this study were drawn from the first Korea Media Panel Study in 2012 of Korea Information Society Development Institute. This study categorized adopters depending on the usage rate of contents and the variety of media platforms they used. Consumers using various media platforms enjoyed more categories of contents provided by Nscreen services. The variety of media platforms was useful in grouping users to explain the difference between the groups in terms of lifestyle activities. Based on the factor analysis and cluster analysis based on the consumers' lifestyle to find out different characteristics of each clusters, the result elicited some implications.

• Journal of Korea Water Resources Association
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• v.32 no.4
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• pp.417-426
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• 1999

A series of numerical experiments is performed to compare the characteristics of outflow hydrograph using linear and nonlinear Muskingum-Cunge methods for two cases: (a) sinusoidal inflow hydrographs and (b) rainfall inputs. The nonlinear method shows the steepening of the rising limb, coupled with a corresponding flattening of the receding limb. The linear method conserves mass exactly. In contrast, the nonlinear method is subject to a gain and a loss of mass. The loss of mass and the subsidence of peak outflow increases with a mild slope, a small baseflow $q_b$ and a large peak inflow to baseflow ratio $q_p/q_b$. A shock wave and associated numerical instability results in the increase of mass for a steep slope and a large $q_p/q_b$ ratio. While the linear method depends on the reference flow per unit-width, the nonlinear method depends on a baseflow and the $q_p/q_b$ ratio. It is found that, unlike for the sinusoidal inflow, the outflow for the rainfall inputs conserves mass fairly exactly in the nonlinear method.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.2
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• pp.94-106
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• 2018

The epidemiological model is useful for creating simulation and associated preventive measures for disease spread, and provides a detailed understanding of the spread of disease space through contact with individuals. In this study, propose an agent-based spatial model(ABM) integrated with spatial big data to simulate the spread of MERS-CoV infections in real time as a result of the interaction between individuals in space. The model described direct contact between individuals and hospitals, taking into account three factors : population, time, and space. The dynamic relationship of the population was based on the MERS-CoV case in Seoul Metropolitan Government in 2015. The model was used to predict the occurrence of MERS, compare the actual spread of MERS with the results of this model by time series, and verify the validity of the model by applying various scenarios. Testing various preventive measures using the measures proposed to select a quarantine strategy in the event of MERS-CoV outbreaks is expected to play an important role in controlling the spread of MERS-CoV.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.876-880
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• 1999

The surfactant self-diffusion coefficients of mixed micellar solutions of ionic and nonionic surfactants have been measured by the NMR pulsed field gradient spin echo(FT-PGSE) method. In addition, the line widths of $^1H$ NMR signal have been monitored. The system investgated are $C_{12}EO_5/SDS/D_2O$, $C_{12}EO_5/DTAC/D_2O$, and $C_{12}EO_8/SDS/D_2O$. In the sample series, the molar ratios of $D_2O$ to surfactant(ionic+nonionic) were kept constant while the surfactant mixing ratio was varied. For the $C_{12}EO_5$ system, the surfactant self-diffusion coefficient indicates minimum when the surfactant mixing ratio is about 20% ionic surfactant. The observed decrease in self-diffusion coefficients as nonionic surfactant was replaced by ionic surfactant is interpreted to mainly be due to an increased micelle-micelle repulsion. The increase in self-diffusion coefficients occurring at higher fraction of ionic surfactant is shown to be due to a decrease in micelle size. For the $C_{12}EO_8$ system, the effect of the surfactant mixing ratio is much weaker which can be understood by considering the molecular geometry and large headgroup area. The proton NMR line widths correlate well with the self-diffusion coefficients and broadening of the alkyl chain methylene signals is found when the self-diffusion coefficients is low.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.594-602
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• 2010

Since the requirement of the high density integration and thin package technique of semiconductor have been increasing, the main package type of semiconductor will be a chip scale package (CSP). The changes of diffusion coefficient and moisture content ratio of epoxy resin systems according to the change of liquid type epoxy resin and fillers for CSP applications were investigated. The epoxy resins used in this study are RE-304S, RE310S, and HP-4032D, and Kayahard MCD as hardener and 2-methylimidazole as catalyst were used in these epoxy resin systems. The micro-sized and nano-sized spherical type fused silica as filler were used in order to study the moisture absorption properties of these epoxy molding compound (EMC) according to the change of filler size. The temperature of glass transition (Tg) of these EMC was measured using Dynamic Scanning Calorimeter (DSC), and the moisture absorption properties of these EMC according to the change of time were observed at $85^{\circ}C$ and 85% relative humidity condition using a thermo-hygrostat. The diffusion coefficients in these EMC were calculated in terms of modified Crank equation based on Ficks' law. An increase of diffusion coefficient and maximum moisture absorption ratio with Tg in these systems without filler can be observed, which are attributed to the increase of free volume with Tg. In the EMC with filler, the changes of Tg and maximum moisture absorption ratio with the filler content can be hardly observed, however, the diffusion coefficients of these systems with filler content show the outstanding changes according to the filler size. The diffusion via free volume is dominant in the EMC with micro-sized filler; however, the diffusion with the interaction of absorption according the increase of the filler surface area is dominant in the EMC with nano-sized filler.

• The Journal of Society for e-Business Studies
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• v.9 no.3
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• pp.227-241
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• 2004

With the expansion of internet usage and the advanced technology for information and communication, the international e-Trade environment gradually migrates from the VAN/EDI to the global Internet-based e-Traed on an ebXML framework. In an effort to provide a Internet-based e-Trade environment with a security and trust, this paper analyzes security components and proposed the SSL and ebXML security technologies in order to assure of the trust and security over Internet-based e-Trade. In addition, this paper presents 3-phase methodology to realize the secure and trustworthy Internet-based e-Trade. In summary, as the first phase, the e-Trade business processes are re-engineered and the digital signature council for mutual recognition is orgainzed. And as the second phase, the Internet-based e-Trade system and the concerned digital signature technology are implemented. Finally as third phase, the PKI mutual recognition agreement is signed by parties concerned and then the Internet-based e-trade business is started. Furthermore, this paper presents the promising Internet-based e-Trade models where the digital signature can be applied.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.430-433
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• 2001

Voice of IP(VoIP) technology Provides voice service as well as data service via Internet. It has been a promising technology as Internet grows fast and the requirements are increasing. Among the standardized protocols for VoIP, H.323 has been one of the most developed technologies and widely used. Recently, the requirements for standardization of inter-domain interoperability is raised, since it has been developed by focusing on intra-domain service. To meet such requirements, IMTC(International Multimedia Telecommunications Consortium. Inc.) and VoIP Forum have elaborated on interoperability standard based on H.323, respectively in international and domestic markets. In this paper, we describe the call model and specify required functionalities of inter-domain interoperability based on H.323.