• Journal of the Korea Institute of Building Construction
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• v.19 no.2
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• pp.193-200
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• 2019

In the context of increasing threats of EMP by neighboring countries in the security situation on the Korean peninsula, EMP protection facilities are a very important means of ensuring military operational capability. These EMP protection facilities should be constructed by comprehensively judging various factors about operation units. However, Defense Military Facilities Criteria and National Technical Guideline for EMP protection require at least 80dB shielding effectiveness without considering other options. In this study, we use objective and statistical methods to refine the consideration of the required EMP protection level based on the opinions of the experts. To do this, the Delphi technique is used for this study, and the survey was conducted from 53 experts related to EMP protection standard in the military and civilian sectors. The first questionnaire investigated the appropriate level of EMP protection, and the second questionnaire analyzed the factors considered in establishing EMP protection level. As a result of the factor analysis on the opinions of the experts, it was concluded that the EMP protection requirement level should be determined by variables of METT + TC.

• Journal of the Korea Institute of Building Construction
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• v.19 no.2
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• pp.167-174
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• 2019

Protective facilities are the last means of ensuring the survivability of personnel and assets, and there is a greater amount of matters to consider than those of general buildings. However, the Defense Military Facilities Criteria and the Ministry of the Interior and Safety, Ordinance No. 20, are only considering the expected enemy threats. In this study, we use objective and statistical methods to refine the consideration of the required capacity of protection based on the opinions of the experts. Specifically, the study adopts the Delphi technique associating the experts related to 30 defense military facilities criteria. The first-round questions were open-ended, and it compiled the points to consider related to the bulletproof and explosion - proof design. The second questionnaire was applied as closed questionnaire with 7 points scale methods. As a result of the factor analysis on the opinions of the experts, it was confirmed that the protection requirement level was due to METT + TC.

• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.41-50
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• 2010

This study presented a model that can enable a reliability analysis for the repair and replacement cycle of a building by using background repair and replacement data and expert opinion as foundation data and applying Monte Carlo Simulation. The presented model offers the time of the repair and replacement of building elements for the period of a year, and supports the prediction of repair and replacement and expenses demand in advance while planning the maintenance of a building. In addition, the model will significantly reduce the risks to the building owner with regard to maintenance decisions. In addition, when a person in charge of the maintenance of large-scale building assets is having difficulties making decisions regarding the repair and replacement of existing building elements due to a lack of background data to support a long-term policy on the repair and replacement requirements, an engineering solution that can ensure the adequacy of this is provided. In summary, it can be largely divided into three study results. First, a method of estimating the repair and replacement cycle that can deal with the development of a construction system was developed. Second, a probabilistic methodology that can quantify the risk of the repair and replacement cycle was proposed. Third, the proposed model can be used as a means of supporting designer and constructor in making decisions for the life cycle plan of a building during a construction project.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.230-238
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• 2017

Carbonation is a representative deterioration for underground structure, which causes additional repair for service life. This study proposes a simplified equation for optimum repair timing without complicated probability calculation, considering initial and repair conditions For the work, initial service life, extended service life through repair, and their COVs(Coefficient of Variation) are considered, and the periods which can reduce number of repair are evaluated. Assuming the two service lives to be independent, the repair timings are derived from 10 to 50 years based on the probabilistic method, and the regression analysis technique for optimum repairing timing is proposed. Decreasing COV has insignificant effect on reducing repairing number but shows a governing effect on changes in probability near the critical repairing stage. The extension of service life through repairing is evaluated to be a critical parameter for reducing repairing number. The proposed technique can be efficiently used for maintenance strategy with actual COV of initial and additional service life due to repairing.

• Spatial Information Research
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• v.18 no.1
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• pp.77-87
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• 2010

Spatio-temporal join operators are essential to the management of spatio-temporal data such as moving objects. For example, the join operators are parts of processing to analyze movement of objects and search similar patterns of moving objects. Various studies on spatio-temporal join queries in outdoor space have been done. Recently with advance of indoor positioning techniques, location based services are required in indoor space as well as outdoor space. Nevertheless there is no one about processing of spatio-temporal join query in indoor space. In this paper, we introduce continuous spatio-temporal self-join queries in indoor space and propose a method of processing of the join queries over stream data of moving objects. The continuous spatio-temporal self-join query is to update the joined result set satisfying spatio-temporal predicates continuously. We assume that positions of moving objects are represented by symbols such as a room or corridor. This paper proposes a data structure, called Candidate Pairs Buffer, to filter and maintain massive stream data efficiently and we also investigate performance of proposed method in experimental study.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.285-285
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• 2015

댐 및 저수지 시설물은 노후화나 안전성 미확보로 인한 파손 또는 붕괴 발생 시 하류부에 막대한 인명과 재산피해 등 치명적인 결과를 초래하게 된다. 이러한 대형 안전사고를 예방하고자 시설물의 안전관리에 관한 특별법에서는 댐 시설물을 규모별로 1, 2종 시설물로 구분하고, 이에 대해 주기적으로 안전점검 및 정밀안전진단을 실시하도록 제도화하는 한편 진단 결과에 따라 보수 보강 등의 안전조치를 의무화하고 있다. 구조물 결함에 따른 보수 보강은 보수재료와 공법 선정시 공법의 적용성, 구조적 안전성, 경제성 등을 종합적으로 검토하여 결정하여야 한다. 손상 부위에 대한 보수 보강은 제한된 예산과 인력을 효율적으로 투자하기 위해 보수재료 및 공법의 선정 뿐만 아니라 보수 보강이 이루어져야 하는 부재에 대한 우선순위를 산정하는 것이 최우선적으로 선행되어야 한다. 안전점검 및 정밀안전진단 세부지침에서는 보수 보강 대책 마련 시안전점검 및 정밀안전진단 결과를 기초로 하여 적정 재료 및 공법을 선정하고, 보수 보강의 수준 및 우선순위를 결정하도록 명시되어 있다. 하지만 우선순위 결정에 대한 가이드라인이 부재하여 불필요한 시공과 비효율적인 예산 투입으로 인해 국가예산의 낭비되고 시설물의 안전까지 위협받게 되는 경우가 발생하고 있다. 따라서 본 연구에서는 시설물의 상태에 따른 적절한 보수 보강 필요성을 판단하고 보수 보강 수준 및 우선순위를 결정하기 위한 방법론을 개발하였다. 댐 시설물에 대한 안전점검 및 정밀안전진단의 종합평가는 평가대상 개별시설에 대하여 상태 평가 및 안전성 평가를 실시한 후 그 결과에 의해 산출된 상태평가지수와 안전성평가지수를 비교하여 평가단계별로 그 결과를 취합하여 종합평가를 실시하고 있다. 따라서 상태평가에 의해 산정된 종합평가 결과를 이용하여 개별 부재의 상태평가값 산정을 위해 하부 단계의 가중치 및 평가 지수 역산하고, 재산정된 가중치 및 평가지수를 이용하여 각 부재에 대한 보수 보강 우선순위를 산정하고자 하였다. 개발된 방법론은 점검 진단 책임기술자 및 시설물 관리주체 담당자가 댐 시설물의 개별부재에 대한 보수 보강 실시 여부를 판정할 수 있는 기준으로, 보수 보강에 대한 정책 결정시 경제성을 고려한 신뢰도 있는 기준으로 활용될 수 있을 것으로 기대된다.

• Korean Journal of Construction Engineering and Management
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• v.20 no.2
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• pp.95-104
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• 2019

EPC plant projects are large and complex, requiring systematic working methodologies, accumulated data, and thorough planning through communications between the entities. In this study, the method of extracting the process planning information using asset data of the plant project and using it to present the initial process plan is presented through the concept of IAP(Interactive Planning). In order to carry out the effective IAP at the early stage of the project, this study extracted the schedule element information from the asset data, created the process plan for each work package, and applied it to the sample project case. Through the proposed IAP methodology, it is possible to promote the utilization of asset data, to identify schedule risks, and to develop countermeasures, which can form the basis for establishing the process management strategy to successfully complete the project.

• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.655-666
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• 2021

Purpose: This study is to develop a method for measuring dynamic speeding risks using vehicle trajectory big data and to demonstrate the feasibility of the devised speeding index. Method: The speed behaviors of vehicles were analysed in microscopic space and time using individual vehicle trajectories, and then the boundary condition of speeding (i.e., boundary speed) was determined from the standpoint of crash risk. A novel index for measuring the risk exposure of speeding was developed in microscopic space and time with the boundary speed. Result: A validation study was conducted with vehicle-GPS trajectory big data and ground-truth vehicle crash data. As a result of the analysis, it turned out that the index of speeding-risk exposure has a strong explanatory power (R²=0.7) for motorway traffic accidents. This directly indicates that speeding behaviors should be analysed at a microscopic spatiotemporal dimension. Conclusion: The spatial and temporal evolution of vehicle velocity is very variable. It is, hence, expected that the method presented in this study could be efficaciously employed to analyse the causal factors of traffic accidents and the crash risk exposure in microscopic space using mobility trajectory data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.269-278
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• 2018

In Korea, BIM technology is applied mainly to building construction projects, but is expected to be applied rapidly to civil engineering projects because the government is currently considering the mandatory application of BIM for infrastructure facilities. Because the infrastructure project is processed in a horizontal work area, the application of BIM technology is more useful in the schedule management of the construction phase than the interference management of the design phase. The 4D CAD system is a typical BIM technology applied to the schedule management in the construction phase, but the application to the actual project is limited due to the lack of practical functions. This study examined the functions of four representative 4D CAD systems commercialized so that the selection criterion can be provided according to the characteristics of the project, and suggests that the functions that should be improved to have practicability. As a result of functional analysis, the application characteristics of each system were analyzed and the user convenience was suggested. In addition, a linear 4D simulation methodology was developed to improve the functions applicable to civil engineering projects, and ways to improve the utilization of the infrastructure projects as the construction phase BIM were suggested. In railway and road construction projects, most activities, such as earthwork, bridges, and tunnels proceed along the distance axis in a horizontal space. Therefore, a linear 4D simulation method, in which an activity is expressed along a distance axis, can be more practically useful rather than a simple 4D simulation method with a Gantt chart.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.467-468
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• 2010

Over the past few decades, considerable numbers of studies on the durability of concrete have been carried out extensively. The majority of these researches have been performed on sound uncracked concrete, although most of in-situ concrete structures have more or less micro-cracks. It is only recent approach that the attention has shifted towards the influence of cracks and crack width on the penetration of chloride into concrete. The penetration of chlorides into concrete through the cracks can make a significant harmful effect on reinforcement corrosion. Author of this study examined the effect of cracks on chloride penetration by short term experiment. However, it is necessary to accomplish the effect by long term experiment to get reliable goal. In this study, the long term and short term experiments were carried out. This can be useful for establishing new species model of chloride penetration through cracks in concrete.