• Journal of the Earthquake Engineering Society of Korea
• /
• v.7 no.4
• /
• pp.31-37
• /
• 2003

This paper presents the methodologies for seismic retrofitting of cabinet equipment which can be employed to resolve the USI A-46 problem related to seismic qualification of old nuclear power plant. To obtain accurate dynamic characteristics of a cabinet structure, three types of structural modeling are introduced and the their free vibration modes are compared. Three types of seismic retrofitting scenarios, such as 1) the installation of bracing, 2) installation of damper, 3) installation of tuned mass damper(TMD), are established and evaluated for the decrease of ICRS(In Cabinet Reponse Spectrum). In the cases of 1) ＆ 2), since the retrofitted structures show larger ICRS than that of the original structure, the careful considerations are need in the application of these methods. Though the installation of TMD shows the best retrofitting result, the construction of analysis model that indicate the accurate vibration modes of real structure is estimated the essential step of this retrofitting method.

• Journal of Climate Change Research
• /
• v.7 no.3
• /
• pp.315-324
• /
• 2016

The relevant ministries, including the Ministry of Environment in Korea, provided Post-2020 Long-term Mitigation Target and Implementation Plan. The plan consisted of four Business As Usual (BAU) reduction levels by 14.7%, 19.2%, 25.7%, and 31.3% until 2030. The Korean government finalized the mitigation target of 37%. But all the initial alternatives were below the goal, 30% from BAU, that has been promised to the international community as well as set out in the Framework Act on Low Carbon Green Growth. In order to achieve a specific goal, performance management should pursue "Justify doing the right things." Otherwise, performance management would not work properly. According to Kingdon's Policy Stream Framework, abnormal alternatives are difficult to be presented as scenarios because alternative building should focus on the role of the need to adhere to the basic principles and professionals. Such a result is possible only when the policy actors does not balance themselves. Performance management statistics has been analyzed by 6 years CCPI data since 2011, taking into account the impact after enactment. This study also has been complemented by a variety of sources, including the media, documents, and artifacts during the period. As a result, raising awareness about climate change was analyzed as one of the solutions because the climate change issue affects the normal performance management throughout the life of the people to stay linked to the environment.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.324-324
• /
• 2019

최근 급격한 기후변화 및 도시화로 인해 강우시 첨두유량이 증가하고, 도심 및 농촌지역에 비점오염원과 관련된 문제가 빈번하게 발생하고 있는 실정이다. 비점오염원에 대한 관리는 발생원 및 특성 파악이 어려운 특성으로 인해 관리가 미흡하며, 이에 따라 비점오염원 관리의 중요성이 커지고 있다. 각 토지이용별로 발생하는 비점오염원을 적절하게 관리하기 위해서는 유역별 비점오염원 발생특성에 대한 파악이 우선적으로 이루어져야 하며 다양한 관리기법에 대한 분석이 필요하다. 이에 본 연구에서는 SWAT모형을 이용하여 비점저감시설을 적용하였을 때의 비점오염부하량의 변화에 대한 분석을 진행하였다. 본 연구에서는 도시유역, 농업유역, 복합유역을 대상으로 비점저감시설을 적용하였을 때 비점오염부하량의 변화를 분석하였다. 우선 유역별 유출량 및 비점오염부하량을 모의하기 위하여 SWAT모델을 사용하였다. 모의된 유출량 및 비점오염부하량은 수질 측정 성과를 이용하여 보정을 수행하였다. 이후 비점오염 취약 소유역 선정을 위해 수질항목별 연간 비점오염부하량 크기에 따라 순위를 산정하고, 순위를 산술 평균하여 소유역별 전체 오염원에 대한 비점오염부하량 순위를 산정하였다. 비점오염 취약 소유역에 BMPs 및 LID를 적용한 결과, 도촌천의 비점오염 취약 소유역에서 SS, $NO_3-N$, TP의 평균 저감효율은 각각 11.17%, 3.47%, 18.85%로 나타났다. 공지천 도시지역에 LID 적용시 비점오염 취약 소유역에서 SS, $NO_3-N$, TP의 평균 저감효율은 각각 0.67%, 5.77%, 1.86%로 나타났다. 또한 공지천 농촌지역에 BMPs 적용시 SS, TN, TP의 평균 저감효율은 각각 14.22%, 1.67%, 4.43%로 나타났다. 또한 설성천의 비점오염 취약 소유역에서의 SS, TN, TP의 평균 저감효율은 각각 57.29%, 7.48%, 14.84%로 나타났다.

• Computers and Concrete
• /
• v.24 no.4
• /
• pp.379-397
• /
• 2019

Steel-concrete composite beams are widely employed in constructions and their performance at the serviceability stage is of concern among practitioners and design regulations. In this context, an accurate evaluation of long-term deflections via various rheological concrete models is needed. In this work, the performance and predict capability of some concrete creep and shrinkage models ACI, CEB, B3, FIB and GL2000 are ascertained, and compared by using statistical bias indicators. Ten steel-concrete composite beams with existing experimental and numerical results are then modeled for this purpose. The proposed modeling technique uses the finite element method, where the concrete slab and steel beam are modeled with shell finite elements. Concrete is considered as an aging viscoelastic material and cracking is treated with the common smeared approach. The results show that when the experimental ultimate shrinkage strain is used for calibration, all studied rheological models predict nearly similar deflections, which agree with the experimental data. In contrast, significance differences are encountered for some models, when none calibration is made prior to. A value between twenty and thirty times the cracking strain is recommended for the ultimate tensile strain in the tension stiffening model. Also, increasing the relative humidity and decreasing the ambient temperature can lead to a substantial reduction of slab cracking for beams under negative flexure. Finally, there is not a unique rheological model that clearly excels in all scenarios.

• Asian Journal of Innovation and Policy
• /
• v.10 no.2
• /
• pp.195-211
• /
• 2021

This paper measures the economic impacts of the U.S. port investment strategies coping with the Panama Canal expansion. Using secondary import data, negative and positive estimates of the impacts were presented in this study. Reduced port activities into the West Coast Customs Districts negatively affect transportation and warehousing industries, among other effects. Still, they have simultaneous positive effects in other states from increased imports resulting from modal shifts and changes in the entry port located in the South and East coasts. This study applied the supply-driven National Interstate Economic Model that measures all interstate trade among the U.S. states to divert foreign imports from 15 Pacific Rim countries. For this purpose, the following assumption was adopted: larger ships using the canal will lead to a redirection of seaborne trade among U.S. (and other) ports and result in secondary effects, e.g., using different freight modes and regional growth spillovers. This study also accounted for the entry point change and significant port investments for foreign trade under alternative scenarios. The choice of ports for international trade depends on decisions about how to minimize multimodal delivery costs. The total direct reduction of transportation and warehousing activities associated with foreign imports in the West Coast ports was estimated at $3.3 billion, leading to total negative effects of $5.8 billion. Total positive impacts from the shift of transportation modes with the choice of an entry port and new warehousing activities for foreign imports in the selected 12 states varied. As expected, states that involved an entry port had the most prominent benefits, but Texas, New York, and New Jersey may be benefited through all the port enhancement projects in the U.S. Also, except for Transportation and Postal, and Warehousing industries, Construction is another dominant positive affected industry of the Canal expansion in the U.S.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.24 no.2
• /
• pp.115-126
• /
• 2021

Strategic Environmental Impact Assessment (SEA) is a decision-making process taking into account the environmental impact, economic and social impact of policies, plans, and programs at the higher stage prior to the project plan for promoting sustainable development. In this study, we analyzed the process and criteria for selecting appropriate alternatives when establishing development plan in SEA. First, the criteria for estimating changes in ecosystem services following the implementation of development project of industrial complex were presented. Second, alternative evaluations were conducted through an analysis of ecosystem service scenarios to explore suitable alternatives in Anseong. As a result, the environmental quality of selected area as the existing project site deteriorated according to the implementation of the project, and the dimensional reduction technique confirmed that the change in ecosystem service factors in project area was the optimal location. In addition, the results of the scenario assessment to explore suitable alternatives in Anseong City showed that the existing site had large capacity in terms of water quality control services (scenario 1), scenario 2 in terms of preconditioning services, and scenario 3 in terms of water supply services. The guidance of Ecosystem service assessment is expected to be available in decision-making of large-scale strategies (e.g., SEA) and projects by presenting more quantitative criteria for determining the adequacy and location feasibility of development plans and policy plans. This is expected to require various support, including legislation and revision of related laws, believed to be supported by advanced research.

• Journal of Advanced Navigation Technology
• /
• v.23 no.4
• /
• pp.265-272
• /
• 2019

In this paper, we selected commuting scenarios in the most congested metropolitan area in Korea, and conducted noise analysis during personal air vehicle (PAV) operation using aviation environmental design tool (AEDT)software which was developed by Federal Aviation Administration (FAA). Noise is the second important factor after safety in order to operate PAVs through concepts such as ODM (on-demand mobility) introduced by National Aeronautics and Space Administration (NASA). Noise analysis were performed by modeling low-noise ePAVs as commercial helicopters and predicted residential suitability in order to resolve problems in which accurate NPD (noise power distance) data from PAVs were not released. The application of noise reduction technology such as electric propulsion has significantly reduced noise exposure levels and has reached the conclusion that commuting with PAVs is feasible without noise problems in the metropolitan area.

• Journal of Korea Water Resources Association
• /
• v.52 no.5
• /
• pp.373-380
• /
• 2019

In this study, the optimum pump operation technique is suggested to decrease the damage rate of water distribution system. Pump operation system was developed to achieve the effective pump operation. Pressure sensors which can communicate with pumps are installed at the end of water distribution system. Pump operation system can control the pressure of water pump according to data sent from the pressure sensors. Therefore, water distribution system can reduce the pressure and maintain enough pressure which can supply the demand of water users. For proving effectiveness of new system, reliability model was introduced to compare the results of damage rates between the maintaining high pressure and selective pressure in water pump. Unsteady analysis was conducted with several scenarios. And the results were used to calculate the probability of pipe breakage. From the results, it was found that new pump operation system can reduce the energy usage and probability of pipe breakage by applying to pumps.

• Journal of Korean Society on Water Environment
• /
• v.34 no.6
• /
• pp.591-601
• /
• 2018

Optimized BMP plans for controlling water quality using the Pareto trade-off surface curve in upper basin of Namgang Dam is proposed. The proposed alternatives consist of BMP installation scenarios in which the reduction efficiency of non-point pollutants is maximized in a given budget. The multi-objective optimization process for determining the optimal alternatives was performed without direct implementation of a watershed model such as SWAT analysis, thereby reducing the time taken. The shortening of the calculation time further enhances the applicability of the multi-objective optimization technique in preparing regional water quality management alternatives. In this study, different types of BMP are applied depending on the land use conditions. Fertilizer input control and vegetative filter strip are considered as alternatives to applying BMP to the field but only control of fertilizer input can be applied to rice paddies. Fertilizer input control and vegetative filter strip can be installed separately or simultaneously in a hydrologic response unit. Finally, 175 BMP application alternatives were developed for the water quality management of the upper river basin of Namgang dam. The proposed application alternative can be displayed on the map, which has the advantage of clearly defining the BMP installation location.

• Earthquakes and Structures
• /
• v.20 no.2
• /
• pp.215-224
• /
• 2021

The carbon dioxide present in the atmosphere is one of the main reasons for the corrosion of bridges, buildings, tunnels, and other reinforced concrete (RC) structures in most industrialized countries. With the growing use of fossil fuels in the world since the Industrial Revolution, the amount of carbon dioxide in urban and industrial areas of the world has grown significantly, which increases the chance of corrosion caused by carbonation. The process of corrosion leads to a change in mechanical properties of rebars and concrete, and consequently, detrimentally impacting load-bearing capacity and seismic behavior of RC structures. Neglecting this phenomenon can trigger misleading results in the form of underestimating the seismic performance metrics. Therefore, studying the carbonation corrosion influence on the seismic behavior of RC structures in urban and industrial areas is of great significance. In this study, a 2D modern RC moment frame is developed to study and assess the effect of carbonation corrosion, in 5-year intervals, for a 50 years lifetime under two different environmental conditions. This is achieved using the nonlinear static and incremental dynamic analysis (IDA) to evaluate the reinforcement corrosion effects. The reduction in the seismic capacity and performance of the reinforced concrete frame, as well as the collapse probability over the lifetime for different corrosion scenarios, is examined through the capacity curves obtained from nonlinear static analysis and the fragility curves obtained from IDA.