• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.482-490
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• 2015

In this study, considering the factors that affects sediment trapping efficiency of Vegetative Filter Strips (VFS), the scenarios were designed to develop a regression equation to estimate sediment trapping efficiency of VFS for agricultural fields in South-Korea. For this, general conditions of agricultural fields in South-Korea were investigated. Then, based on these results, total 53,460 scenarios were set and simulated by Vegetative Filter Strip MODel (VFSMOD-w). Two variables were determined from the results of 53,460 scenarios. These two variables were applied to CurveExpert for development of a equation, which can estimate sediment trapping efficiency of VFS. The equation developed in this study can be used in SWAT model for estimation of sediment reduction efficiency of VFS to upland field in Korea. Moreover, it is expected that VFS will be effectively applied to agricultural fields in South-Korea.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.166-180
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• 2015

Pollutant in watersheds comes from two major sources which are NPS (nonpoint source pollution) and PS (point source pollution). Most of the pollutant can be treated by wastewater treatment plants. However, wastewater treatment plants may not be an appropriate practice to improve water quality for the watersheds with large portion of NPS pollutant and NPS pollution from direct runoff and baseflow has different characteristics. Therefore the practices to improve water quality need to be comprehensive for pollutants by both direct runoff and baseflow. Riparian buffer, one of practices to manage pollutant in watershed, has been applied to reduce pollutant not only from direct runoff but also baseflow. In this study, the scenarios for pollutant reduction by wastewater treat plants and the nitrogen reduction by riparian buffer were simulated using SWAT-REMM to suggest an effective plan for pollutant reduction from baseflow. Riparian buffer provided nitrogen reduction of 0.2~75.0% in YbB watershed and 38.0~47.0% in GbA watershed. The result indicates that riparian buffer is effective to reduce the pollutant especially from baseflow, and it suggested as suitable for the a watershed which WWTP discharge is not capable to reduce enough pollutant.

• The Southeast Asian review
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• v.24 no.2
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• pp.35-79
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• 2014

This study examines the measures for the activation and the growth of intra-regional trade in Southeast Asia taking a look at the four dimensions of tariff rates, non-tariff barriers, trade facilitations, and trade infrastructures. Utilizing a gravity model, we performed empirical analysis and discussed the policy implications with the priorities to implement. To expand the intra-regional trade in Southeast Asia it would be necessary to enhance the level of trade facilitations and provide trade infrastructures, such as ports and airports as well as cutting the tariff rates and eliminating the non-trade barriers. In particular, in the case of exports of ASEAN6 to ASEAN6 the infrastructure is the important factor. Also, in the case of the exports of ASEAN6 to CLMV(Cambodia, Laos, Myanmar, and Vietnam), it is expected that eliminating non-tariff barriers and enhancing trade facilitations may play important roles in the progress of intra-regional trade. These results may provide the important implications for Southeast Asian countries, which are trying to promote intra-regional trade ahead of the constitution of ASEAN Economic Community by 2015. Southeast Asian countries could be evaluated to achieve a certain level of trade liberalization and economic integration through the formation of AFTA. But in order for Southeast Asia to develop to advanced economic integrated region it requires mutual cooperations and policy harmonizations among regional countries. Also, for the elimination of non-tariff barriers, promoting trade facilitations, and providing infrastructures, the administrative, legal, and institutional measures would have to be fulfilled in advance. In addition, capital investment for constructing infrastructures would be necessary to realize the intra-regional trade expansion. However, to achieve the goal, it would require a large capital investment and highly mandated policy considerations and harmonizations among Southeast Asian countries in terms of further trade liberalization and economic integration.

• Smart Structures and Systems
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• v.24 no.5
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• pp.567-585
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• 2019

In the past two decades, structural health monitoring (SHM) systems have been widely installed on various civil infrastructures for the tracking of the state of their structural health and the detection of structural damage or abnormality, through long-term monitoring of environmental conditions as well as structural loadings and responses. In an SHM system, there are plenty of sensors to acquire a huge number of monitoring data, which can factually reflect the in-service condition of the target structure. In order to bridge the gap between SHM and structural maintenance and management (SMM), it is necessary to employ advanced data processing methods to convert the original multi-source heterogeneous field monitoring data into different types of specific physical indicators in order to make effective decisions regarding inspection, maintenance and management. Conventional approaches to data analysis are confronted with challenges from environmental noise, the volume of measurement data, the complexity of computation, etc., and they severely constrain the pervasive application of SHM technology. In recent years, with the rapid progress of computing hardware and image acquisition equipment, the deep learning-based data processing approach offers a new channel for excavating the massive data from an SHM system, towards autonomous, accurate and robust processing of the monitoring data. Many researchers from the SHM community have made efforts to explore the applications of deep learning-based approaches for structural damage detection and structural condition assessment. This paper gives a review on the deep learning-based SHM of civil infrastructures with the main content, including a brief summary of the history of the development of deep learning, the applications of deep learning-based data processing approaches in the SHM of many kinds of civil infrastructures, and the key challenges and future trends of the strategy of deep learning-based SHM.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.401-415
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• 2019

Recently, there has been a lot of studies and efforts to strengthen the stability of critical infrastructures against increasing cyber attacks to critical infrastructures. In this thesis, I defined what cyber threats are, after showing you various definitions about what cyber threats are and what the types are. After studying about significant cyber threats from China, I showed you the realities of cyber threats with the analysis about starting points, types of cyber threats, ratios of attacks and so on. At last, I defined guidelines about unnecessary oversea IP range blocking. Also, I proposed unnecessary oversea IP range blocking methodologies with per information system and per network system. Furthermore, I proposed blocking characteristics per security equipment and security operation improvement and blocking effects and service process to normal oversea users.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.93-94
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• 2021

The Korean government has invested a tremendous amount of money in the last 10 years to build large public research infrastructures (LPRI). For efficient operation and maintenance of LPRI built with expensive equipment and professional engineers, reasonable budget needs to be allocated. However, it is difficult to fulfill sustainable operation and maintenance (O&M) because there is no standard on budgeting for efficient LPRI operation, including expensive equipment and manpower allocation. There have been a lot of cost assessment studies regarding O&M of high-demand facilities such as hospitals, hotels and residential buildings, but a very few on sustainable O&M of LPRI. Therefore, mid/long-term budget establishment plans for efficient LPRI O&M are required from the initial planning stage and a cost assessment model to support the plans should be developed. The objective of this paper is to propose a cost assessment model for sustainable operation and maintenance of large public research infrastructures. To do so, actual O&M data of 6 LPRI types in operation are collected, and regression analysis model (RAM) is used for development and evaluation a cost assessment model. The study result will support sustainable operation of LPRI from a business perspective and be used as basic data for continuous development of cost assessment models to establish budgets for LPRI operation from an academic perspective.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.241-246
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• 2008

Design of a high-speed railway line requires collaboration of heterogeneous application systems and of engineers with different background. Object-based 3D models with metadata can be a shared information model for the effective collaborative design. In this paper, railway infrastructure information model is proposed to enable integrated and inter-operable works throughout the life-cycle of the railway infrastructures, from planning to maintenance. In order to develop the model, object-based 3-D models were built for a 10km railway among Korea high-speed railway lines. The model has basically three information layers for designers, contractors and an owner, respectively. Prestressed concrete box-girders are the most common superstructure of bridges. The design information layer has metadata on requirements, design codes, geometry, analysis and so on. The construction layer has data on drawings, real data for material and products, schedules and so on. The maintenance layer for the owner has the final geometry, material data, products and their suppliers and so on. These information has its own data architecture which is derived from similar concept of product breakdown structure(PBS) and work breakdown structure(WBS). The constructed RIIM for the infrastructures of the high-speed railway was successfully applied to various areas such as design check, structural analysis, automated estimation, construction simulation, virtual viewing, and digital mock-up. The integrated information model can realize virtual construction system for railway lines and dramatically increase the productivity of the whole engineering process.

• Journal of KIISE:Information Networking
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• v.29 no.5
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• pp.459-465
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• 2002

Ad-hoc networks have the dynamic topology characteristics and most of the applications on ad-hoc networks require the group communication capability. Previously proposed multicast mechanisms on mobile ad-hoc networks build multicast-infrastructures like the tree or mesh for the group communication and these infrastructures nay cause significant overhead especially in a highly dynamic mobile ad-hoc network environment. Therefore, in this paper, we propose a new multicast mechanism supporting multicast services based on only the underlying unicast routing tables, hence any multicast-related infrastructures like trees and meshes are not required to be constructed.

• Computers and Concrete
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• v.21 no.1
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• pp.95-102
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• 2018

Reinforced concrete corbel beams (span to depth ratio of a corbel is less than one) are designed with primary reinforcement bars to account for bending moment and with the secondary reinforcement placed parallel to the primary reinforcement (shear stirrups) to resist shear force. It is interesting to note that most of the available analytical procedures employ empirical formulas for the analysis of reinforced concrete corbels. In the present work, a generalized and a simple strut and tie models were employed for the analysis of reinforced corbel beams. The models were benchmarked against experimental results available in the literature. It was shown here that increase of shear stirrups increases the load carrying capacity of reinforced concrete corbel beams. The effect of horizontal load on the load carrying capacity of the corbel beams has also been examined in the present paper. It is observed from the strut and tie models that the resistance of the corbel beam subjected to combined horizontal and vertical load did not change with increase in shear stirrups if the failure of the corbel is limited by concrete crushing. In other words, the load carrying capacity was independent of the horizontal load when failure of the beam occurred due to concrete crushing.

• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.56-62
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• 2015

Recently, one of countermeasures against aging SOC infrastructures, performance-focused management including the serviceability, functionality, durability, and economics has been changed from the structural safety-focused evaluation has changed into The current inspection and diagnosis for the major SOC facilities in Korea has been carried out by the specific principle of details, and most of them checked by the visual inspection are focused on the repair and rehabilitation of the damaged structures, thus they are the preventive maintenance. However, the performance-focused management should be replaced for the effective and economic maintenance as wells as for the minimization of the damage. In this regard, this study the appropriacy of the current evaluation items about the concrete retaining wall, one of SOC infrastructures as the previous step forward the performance-focused management. In order to deduct the effective evaluation items in order, the entropy, analytic hierachy process (AHP), and promethee analysis were peformed and the results were compared and discussed.