• Journal of Advanced Navigation Technology
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• v.15 no.5
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• pp.722-728
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• 2011

Most services need to have authentication protocols to verify users' eligibility in the network environment. For this, a lot of user authentication protocols have been researched and developed. Two of them, SPMA and I-SPMA protocols, introduced the lack of mutual authentication and vulnerability to the reply attack of the prior protocols and suggested revised protocols. Nevertheless, these protocols did not mention about the critical problem caused when the server and the client lose synchronization on the secret information between them. Therefore, in this paper, we analyze the security characteristics of the existing protocols and prove the vulnerability to the synchronization of the protocols.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.4
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• pp.175-180
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• 2008

The present study is aimed to investigate relation between Marine Environmental Engineering (MEE) and Environmental Education (EE). This study is necessary for mutual advance toward sustainable future between MEE which has the characteristic of the practicality of the present and EE which has that of the ideality of the future. For this, we analyzed the character of MEE by the theoretical frame of 'Environmental Studies for Environmental Education' that was presented recently as a new theoretical viewpoint of EE. This study prepares a base for the two fields to help each other and to develop as we elucidated the environmental educational character which is considered latent in MEE.

• Proceedings of the CALSEC Conference
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• 1999.07b
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• pp.555-562
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• 1999

연구목적은 CALS와 GIS (Geographic Information Systems)를 융합한 효과적인 전자상거래 운용 및 관리시스템의 개발에 두고 있으며, 이는 CALS와 EC로만 국한된 전자상거래 환경에 융통성 있는 지리정보기술 (Geographic Information Technologies)과의 상호운용에 의한 기법으로 전자상거래를 보완하여 생산과 판매 그리고 판매와 수요간의 비용절감의 효과를 달성하기 위함 에 있다. 전자상거래 분야의 문제점으로서 지역과 지역간에 형성되는 상거래의 공간적인 분포관계나 경제적인 연계관계 등에 대한 구체적인 요인분석이나 대처방안이 제시되고 있지 않고 있으며, 생산지와 분배처 그리고 수요자간의 공간적인 제반문제들에 의한 과도한 물류비용의 부담, 불확실한 수요공급의 추이, 급변하는 경제동향의 이해, 비정형적인 공간거래에 따른 비용의 발생 등이 대상이 되고 있다. 이들 문제점에 대한 해결 방안은 공간간의 상거래 상관관계를 제시해주는 분석기능의 제공, 지역간에 상거래 자료를 기록 관리하게 할 수 있는 공간DB의 도화 편집기능의 제공, 과거에서 현실까지의 자료에 의한 향후의 지리공간에 대한 상거래 추이를 위한 시공간 기능의 제공 등을 들 수 있다. CALS-GIS의 운용에 따른 기대효과는 다음과 같다. GIS의 공간분석기능을 활용하여 상거래 공간간의 지역성이나 경제성에 의한 상호간의 비용발생을 절감한다. GIS의 공간DB의 도화기능을 활용하여 지역사회간의 특성에 대한 자료를 도면에 의한 기록관리로 원활한 운영환경을 만든다. 시공간 모델링 기법 (Spatio-temporal Modeling)으로 과거에서 현재까지의 자료에 의한 향후의 지리공간에 대한 추이를 파악하여 상거래의 전략을 체계적으로 구축한다. 생활지리정보의 제공에 의한 다양한 정보의 접근에 의한 부수적인 관리의 도구로 전환할 수 있는 기반을 제공한다. System 개발을 개방형 환경으로 구축하여 CALS-GIS의 운영 이외의 차세대 신기술까지도 접목할 수 있는 시스템 환경으로 구현되어 제공된다.

• Polymer(Korea)
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• v.26 no.1
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• pp.139-144
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• 2002

In this study, the PPS/ABS blend system was investigated in order to identify the relationship between the incorporation of compatabilizing moieties and the mechanical properties. ABS resin was chemically modified by the incorporation of maleic anhydride using reactive extrusion method to yield MABS resin, and PPS/MABS blend was prepared by a twin screw extruder. Single glass transition behavior was observed in the various compositions of PPS/MABS blend by dynamic mechanical analysis study. Upon the examination of the mechanical properties, the PPS/MABS blend exhibited an enhanced tensile, flexural and impact strength, which might be due to the better chemical compatibilization to result in the reduced interfacial tension between each components.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1740-1746
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• 2013

Augmentative and alternative communication(AAC) is a communication tool for those with impairments or restrictions on the production or comprehension of spoken language. Traditional AAC has used a portable board with pictures and texts with which disabled person could be supported by it. Currently, smart phone based AAC researches and developments are actively studying. With emerging concepts of context-aware computing, the mobile devices can provide mobile users with timely information and location based services. We proposed a adjustable AAC system for disabled people of which has variable layouts and selectable items. We also implemented context-ware application for AAC systems including time, location and click count informations on smart phone. The system can adaptively change its layout and select AAC items depending on various situation of disabled persons.

• Journal of Adhesion and Interface
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• v.22 no.4
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• pp.118-127
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• 2021

In this study, the mechanical properties of vulcanized rubber were evaluated through compounding by controlling filler content to improve the mechanical properties of NBR rubber. Aramid and glass fibers with excellent heat resistance were used as fillers, and ceramics were additionally used in anticipation of a complementary effect, and as for the ceramic materials, needle-shaped and plate-shaped ceramics were used. Each filler was used in an amount of 5.0, 10.0, 15.0, and 20.0 phr in order to investigate the basic properties according to the amount of filler. To confirm the complementary effect through ceramic application, each 10.0 phr fiber and ceramic were mixed with 1:1 ratio to evaluate mechanical properties. As a result, it was confirmed that the decreasing ratio of tensile strength after heat aging was small in the order of aramid fiber, acicular ceramic, glass fiber, and plate ceramic in the case of applying the filler alone. In addition, the mechanical characteristics of vulcanized rubber using composite filler based on fibers and ceramics were evaluated, and it was confirmed that the composite filler had a complementary effect on thermal aging.

• Journal of Korea Water Resources Association
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• v.54 no.spc1
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• pp.1195-1204
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• 2021

Recently, local torrential rain have become more frequent and severe due to abnormal climate conditions, causing a surge in human and properties damage including infrastructures along the river. In this study, water surface elevation prediction algorithm was developed using the LSTM (Long Short-term Memory) technique specialized for time series data among Machine Learning to estimate and prevent flooding of the facilities. The study area is Jamsu Bridge, the study period is 6 years (2015~2020) of June, July and August and the water surface elevation of the Jamsu Bridge after 3 hours was predicted. Input data set is composed of the water surface elevation of Jamsu Bridge (EL.m), the amount of discharge from Paldang Dam (m³/s), the tide level of Ganghwa Bridge (cm) and the number of tweets in Seoul. Complementary data were constructed by using not only structured data mainly used in precedent research but also unstructured data constructed through wordcloud, and the role of unstructured data was presented through comparison and analysis of whether or not unstructured data was used. When predicting the water surface elevation of the Jamsu Bridge, the accuracy of prediction was improved and realized that complementary data could be conservative alerts to reduce casualties. In this study, it was concluded that the use of complementary data was relatively effective in providing the user's safety and convenience of riverside infrastructure. In the future, more accurate water surface elevation prediction would be expected through the addition of types of unstructured data or detailed pre-processing of input data.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.271-274
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• 2009

강관의 내부에 콘크리트를 충전한 콘크리트 충전 강관 구조(CFT 구조, Concrete Filled Steel Tubular Structure)는 강재와 콘크리트의 단점을 상호 보완하고, 장점을 극대화 할 수 있다는 이점 때문에 최근 실제 구조물의 시공에 적용하는 사례가 증가하고 있는 추세이다. 이와 같은 CFT 거더의 장점을 살리면서 CFT 거더보다 더 뛰어난 경제적, 구조적 효율성을 얻기 위해 기존의 CFT 구조에 아치 형식과 프리스트레스를 도입한 CFTA(Concrete Filled and Tied Tubular Arch) 거더에 관한 연구가 현재 진행중이다. 본 연구에서는 CFTA 거더의 현장 실험과의 비교를 위해 ABAQUS 6.5-1을 이용하여 CFTA 거더의 유한요소 해석을 수행하였고, 이를 바탕으로 구조물의 선형거동을 분석하였다. 또한 구조물의 위험도 분석을 위해 본 구조물의 가장 약점으로 지적되고 있는 외부로 노출되어 있는 긴장재의 차량 충돌에 의한 사고를 가정하여 이를 고려한 유한 요소 해석을 수행하여 CFTA 구조물의 동적 및 정적 안전성 평가를 수행하고 그 결과를 분석하였다.

• Convergence Security Journal
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• v.13 no.5
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• pp.207-213
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• 2013

As the axis of the private security maintain social order in order to achieve the original purpose of all society must move in the direction of motion, and so in order to be a private security based philosophical values and ideological composition should be based. In this process, to be followed by private security value or direction, philosophy private security is the norm. In this regard, this study pursued by the private security justification ever truly normative principles are intended to establish. The public nature of the ideology of private security, public, efficiency, legality, responsiveness and the like. Conflict occurs between the value of these ideals, although complementary are in harmony.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1734-1738
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• 2009

최근 지구의 온난화 및 급격한 기후변화는 전 세계적으로 수해를 촉진 시키며, 이와 같은 기상변화에 따른 우리의 치수 제도는 해마다 증가하는 재해에 대하여 발 빠른 대응을 하지 못하고 있는 실정이다. 따라서 본 연구는 미국, 일본, 유럽의 홍수 특성을 파악한 후 이에 대한 홍수대응 기본방침, 구조적 대책 및 비구조적 대책의 연관성을 고려한 홍수피해 대책, 치수종합계획, 극한홍수 및 이상홍수의 대응 방안 등을 우리나라의 현 치수관련 제도 및 홍수 피해 대책 등과 비교 분석 하였다. 우리나라의 치수 제도는 기본적으로 하천등급 위주의 홍수방어에서 지역특성에 맞는 다양한 방어대책으로의 전환의 필요성이 대두 되었다. 또한 예방, 대비, 대응, 복구의 4단계의 Feedback System이 상호 보완적 이지 못하며, 하천에 대한 계획 수립 및 관리를 중소 유역별 치수 정책에서 국가 차원의 통합치수 정책으로 확장성 있는 치수 정책이 필요함을 알 수 있었다.