• Earthquakes and Structures
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• 제11권6호
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• pp.1061-1076
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• 2016

Prefabricated Modular Buildings are increasingly becoming popular in the construction industry as a method to achieve financially economical buildings in a very short construction time. This increasing demand for modular construction has expanded into multi-storey applications where the effect of lateral loads such as seismic loads becomes critical. However, there is a lack of detailed scientific research that has explored the behaviour of modular buildings and their connection systems against seismic loads. This paper will therefore present the nonlinear time history analysis of a multi-storey modular building against several ground motion records. The critical elements that need special attention in designing a modular building in similar seismic conditions is discussed with a deeper explanation of the behaviour of the overall system.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2012년도 춘계학술대회
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• pp.80-81
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• 2012

우리 사회는 전력의 생산 및 배전 시스템, 통신기술, 텔레커뮤니케이션, 금융시스템, 수송시스템 등의 효율적이고 정상적으로 운영 됨으로써 국가의 중대한 인프라로 구성이 된다. 이런 중대한 인프라 및 그 응용분야는 P.N.T(Positioning, Navigation, Timing) 시스템에 의존하고 있는데 이 P.N.T가 텔레커뮤니케이션(시각동기), 금융시장(시각동기), 물류관리(위치, 항법, 시각동기), 수송(위치, 항법, 시각동기) 등의 버팀목이 된다. 국가적으로 P.N.T 서비스를 지속적으로 사용할 수 있도록 GPS 시스템과 별도의 항법시스템 구축이 필요하여 안정적으로 PNT 서비스를 할 수 있는 시스템 구축에 대한 연구를 하였다.

• 한국통신학회논문지
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• 제30권8C호
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• pp.838-848
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• 2005

전력, 가스, 상하수도, 고속전철 등 국가에서 관리하는 중요핵심기반시설은 대부분 SCADA(Supervisory Control and Data Acquisition) 시스템으로 관리, 운영되고 있다. 최근 이러한 시설들이 사이버 테러 및 해킹, 바이러스 등 에 의하여 원격 조작 및 통제되는 경우 심각한 위험에 빠질 수 있다. 따라서, 중요핵심기반시설에 대한 종합적인 정보보호 관리기법을 수립해야 할 시점에 이르게 되었다. 본 논문에서는 자산, 위협/취약성, 위험도 계산 등의 위험분석 프로세스를 기반으로 정보보호대책(기밀성, 무결성, 가용성) 및 장애처리를 포함한 보안관리 기법을 제안하고자 한다. 이를 위하여 미국, 일본 등 중요핵심기반시설에 대한 정보보호 관리 현황을 알아본다.

• International Journal of Computer Science & Network Security
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• 제23권12호
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• pp.1-12
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• 2023

Ensuring the security of Supervisory Control and Data Acquisition (SCADA) and Industrial Control Systems (ICS) is paramount to safeguarding the reliability and safety of critical infrastructure. This paper addresses the significant threat posed by reconnaissance attacks on SCADA/ICS networks and presents an innovative methodology for enhancing their protection. The proposed approach strategically employs imbalance dataset handling techniques, ensemble methods, and feature engineering to enhance the resilience of SCADA/ICS systems. Experimentation and analysis demonstrate the compelling efficacy of our strategy, as evidenced by excellent model performance characterized by good precision, recall, and a commendably low false negative (FN). The practical utility of our approach is underscored through the evaluation of real-world SCADA/ICS datasets, showcasing superior performance compared to existing methods in a comparative analysis. Moreover, the integration of feature augmentation is revealed to significantly enhance detection capabilities. This research contributes to advancing the security posture of SCADA/ICS environments, addressing a critical imperative in the face of evolving cyber threats.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.432-439
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• 2009

This research project was carried out to develop the technique to assess quantitatively and rapidly the stability of a tunnel by using the measured displacement at the tunnel construction site under excavation. To achieve this purpose, a critical strain concept was introduced and applied to an assessment of a tunnel under construction. The new technique calculates numerically the strains of the surrounding ground by using the measured displacements during excavation. A numerical practical system was developed based on the proposed analysis technique in this study. The feasibility of the developed analysis module was verified by incorporating the analysis results obtained by commercial programs into the developed analysis module. To verify the feasibility of the developed analysis module, analysis results of models both elastic and elasto-plastic grounds were investigated for the circular tunnel design. Then the measured displacements obtained in the field are utilized practically to assess the safety of tunnels using critical strain concept. It was verified that stress conditions of in-situ ground and ground material properties were accurately assessed by inputting the calculated displacement obtained by commercial program into this module for the elastic ground. However for the elasto-plastic ground, analysis module can reproduce the initial conditions more closely for the soft rock ground than for the weathered soil ground. The stability of tunnels evaluated with two types of strains, that is, the strains obtained by dividing the crown displacement into a tunnel size and the strains obtained by using the analysis module. From this study, it is confirmed that the critical strain concept can be fully adopted within the engineering judgment in practical tunnel problems and the developed module can be used as a reasonable tool for the assessment of the tunnel stability in the field.

• 한국인터넷방송통신학회논문지
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• 제23권3호
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• pp.19-26
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• 2023

전 세계적으로 에너지, 금융 서비스, 보건, 통신, 교통 분야의 클라우드 전환에 따라 지속적으로 클라우드제공업체에 대한 주요기반시설 지정 움직임이 확산되고 있다. 또한, 우크라이나 사태에서는 국가 주요시설의 클라우드 사용 규제 철폐와 신속한 주요 데이터에 대한 클라우드 전환으로 인해 러시아의 기반시설을 겨냥한 사이버 공격에 효율적으로 대처할 수 있었다. 한국에서는 체계적, 종합적인 정보보호 관리체계를 구현하고, 조직의 정보보호 및 개인정보보호 관리 수준 향상을 위해 ISMS-P가 기업의 정보보호 및 개인정보보호 수준 제고를 위해 운영되고 있다. 클라우드 환경을 고려한 통제항목이 수정, 추가 되어 기업의 심사에 운영되고 있다. 그러나, 클라우드의 국내외 기술적 수준이 상이하고 하이퍼스케일 규모에 대한 국내 인증심사원들의 교육을 위해서는 Microsoft같은 클라우드 공급업체의 결함사항에 대한 정보를 구하기 쉽지 않았다. 이에, 본 논문에서는 하이퍼스케일 클라우드상 에서의 결함사항을 분석하고, 하이퍼스케일환경과 ISO/IEC 27001 및 SOC 보안 국제 표준과의 정합성을 고려하여 보다 클라우드에 특화된 통제항목 개선방안을 제시하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.546-552
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• 2010

Seasonal frozen ground affects structural behavior in South Korea. Frost and heaving of seasonal frozen ground results in the critical damage of roadway, railroad, and buried pipeline. It has been widely used to substitute frost susceptible soils with granular soils. This paper presents experimental investigation on the effectiveness of soil-shredded tire and soil-expanded polystylene (EPS) mixtures to reduce frost depth and force around a buried pipeline. Experimental data such as measured temperature profile and the deformation of buried pipeline were carefully observed and provide the evidence of the effectiveness of soil mixtures.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.563-572
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• 2007

Transportation infrastructure is critical to economic growth of a country such as China. Careful evaluation of investments in traffic infrastructure projects is therefore pertinent. As traditional evaluation methods do not consider the uncertainty of future cash flows and mobility during project execution, the real option approach is gradually gaining recognition in the context of valuing construction and infrastructure projects. However, many of the cases only evaluate individual options separately although multiple options often exist in a typical large infrastructure project. Using a highway project in China as a case study, this paper first evaluates a deferment option and a growth option embedded in the project. Subsequently, the values are combined using the fuzzy analytical hierarchy process. It is found that the combined value is less than the sum of the two option values. This finding is consistent with the theoretical observations given in past real option literature despite the use of a different approach.

• 국제초고층학회논문집
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• 제12권1호
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• pp.35-47
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• 2023

The transport system and its infrastructure are not only the fundamental means of sustaining the operation of contemporary cities, but also important drivers for the evolution of urban form. Rail transit, critical to improving the operational efficiency and optimizing the spatial layout in cities, is one of the critical conditions for high-density areas with limited land and concentrated resources to be compact to take on complex challenges. As a node element of infrastructure, rail transit entrances are the most important points connecting the rail transit system with urban space. Although influenced by urban form, their quantity and location also influence and shape the evolution of urban space form. Based on the development gap of high-density areas in various contexts, focusing on various rail transit stations in Asia, this research analyzes the correlation between rail transit entrances and peripheral high-density urban form in a delicate, dynamic and granular way. The research considers both horizontal and vertical perspectives, in combination with the urban evolution process in time series, to explore the development trend of high-density urban form in Asia from the aspect of correlation, and building a new foundation for research on urban form, suitable for different types of cities.

• International Journal of Concrete Structures and Materials
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• 제9권4호
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• pp.463-473
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• 2015

Three full-scale instrumented test slabs were constructed and tested using a heavy vehicle simulator (HVS) to evaluate the structural behavior of internally cured concrete (ICC) for use in pavements under Florida condition. Three mix designs selected from a previous laboratory testing program include the standard mixture with 0.40 water-cement ratio, the ICC with 0.32 water-cement ratio, and the ICC mixture with 0.40 water-cement ratio. Concrete samples were prepared and laboratory tests were performed to measure strength, elastic modulus, coefficient of thermal expansion and shrinkage properties. The environmental responses were measured using strain gages, thermocouples, and linear variable differential transformers instrumented in full-scale concrete slabs. A 3-D finite element model was developed and calibrated using strain data measured from the full-scale tests using the HVS. The results indicate that the ICC slabs were less susceptible to the change of environmental conditions and appear to have better potential performance based on the critical stress analysis.