• Journal of the Korean Magnetics Society
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• v.24 no.6
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• pp.171-178
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• 2014

Remote Field Eddy Current Testing (RFECT), one of the ways which is a nondestructive testing using electromagnetic fields, can make up for Magnetic Flux Leakage (MFL) weaknesses and general Eddy Current Testing (ECT) weaknesses which is an occurrence of a huge friction force or disadvantage of detecting defects on the outer wall. So many of institutes and laboratories have studied on RFECT for the past 50 years. But There is a lack of discussion about a study on eddy current and magnetic field distributions in a pipe wall and designing of RFECT exciter coil. In this paper, eddy current and magnetic field distributions in a pipe wall and influence of altering variables are analyzed. Also, the optimal design algorithm about the RFECT Exciter coil are proposed, and influence on defect signals caused by alteration of its shape is analyzed.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.4
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• pp.191-197
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• 2020

Pipe routing is a important part of the whole design process in the shipbuilding industry. It has a lot of constraints and many tasks that should be considered together. Also, the result of this stage affects follow-up works in a wide scope. Therefore, this part requires skilled designers and a lot of time. This study aims to reduce the workload and time during the design process by automating the pipe route design on initial stage. In this study, the reinforcement learning was used for pipe auto-routing. Reinforcement learning has the advantage of dynamically selecting routes, unlike existing algorithms. Therefore, it is suitable for the pipe routing design in ship design process which is frequently modified. At last, the effectiveness of this study was verified by comparing pipelines which were designed by piping designer and reinforcement learning results.

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.373-382
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• 2016

Carbon dioxide Capture and Storage/Sequestration (CCS) technology has attracted attention as an ideal method for most carbon dioxide reduction needs. When the collected carbon dioxide is transported to storage via pipelines, the direct transport is made if the storage is close, otherwise it can also be transported via an intermediate storage hub. Determining the number and the location of the intermediate storage hubs is an important problem. A decision-making algorithm using a mathematical model for solving the problem requires considerably more variables and constraints to describe the multi-objective decision, but the computational complexity of the problem increases and it also does not guarantee the optimality. This research proposes an algorithm to determine the location and the number of the intermediate storage hub and develop a simulator for the connection network of the carbon dioxide emission site. The simulator also provides the course of transportation of the carbon dioxide. As a case study, this model is applied to Korea.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.1
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• pp.171-180
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• 2005

In this study the seismic performance of a three-story knee-braced moment-resisting frame (KBMRF), which is typically employed to support pipelines for oil or gas, was investigated. Nonlinear static pushover analyses were performed first to observe the force-displacement relationship of KBMRF under increasing seismic load. The results show that, when the maximum inter-story drift reached 1.5% of the story height, the main structural members, such as beams and columns, still remained elastic. Then nonlinear dynamic time-history analyses were carried out using eight earthquake ground motion time-histories scaled to at the design spectrum of UBC-97. It turned out that the maximum inter-story drift was smaller than the drift limit of 1.5 % of the structure height, and that the columns remained elastic. Based on these analytical results, it can be concluded that the seismic performance of the structure satisfies all the requirements regulated in the seismic code.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.47-53
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• 2007

The safe operation of high pressure pipe line systems is of significant importance. Leaks due to faulty operation from the pipelines can lead to considerable product losses and to exposure of community to dangerous gases. There are several leak detection methods, which have been recently suggested on pipeline network. The negative pressure wave detection technology, which has advantages of short time detection availability, accurate leaking location estimate capability and cost effective, is concentrated in this study. Theoretical analysis of the flow characteristics for leaking through a hole on the pipe wall has been performed by using CFD++, commercial CFD package. The results of 3-dimensional analysis near leaking hole confirm the occurrence of negative pressure wave and verify the characteristics of propagation of the wave which travels with speed equal to the speed of sound in the pipeline contents. For the application of long pipe line system. The method of 1-dimensional analysis has been suggested and verified with results of CFD++.

• Journal of the Korean Institute of Gas
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• v.21 no.6
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• pp.8-14
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• 2017

One of the main causes of gas pipeline accidents is mechanical impact(third party damage). The majority of high pressure gas pipelines buried in major domestic industrial complexes are old pipes which have being operated over 20 years. Therefore, if an accident occurs, there will be a full scale accident because there is no additional inspection and reinforcement time. In this study, the defects on the piping during the mechanical impact were studied through the third party damage(excavation) experiments. Experiments were carried out using the 21 ton excavator which is operated in the actual excavation work and the type of pipe to be struck are ASTM A106 Grade.B and ASTM A53 Grade.B. As a result, when the bucket used during excavator operation is a sawtooth bucket, the defect is more bigger. And the smaller the diameter of the pipe, the smaller the depth and length of the defect. Also, it was confirmed that the impact height had no effect on the defects on the buried pipe, during the excavation work.

• Industrial Engineering and Management Systems
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• v.15 no.4
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• pp.396-402
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• 2016

In this study, hydraulic analysis of water-supply networks in Marivan was performed by modeling. WATERGEMS was used for modeling and it was calibrated using existing rules and regulations. The purpose of this research is modeling urban water network and its analysis based on hydraulic criteria and meeting pressure conditions at the nodes and complying the economic speed. To achieve this goal, first the pipelines of city streets was designed in AutoCAD on a map of the city. It should be mentioned that it was tried to prevent from creating additional loops in the network and the optimal network was designed by a combination of annular and branch loops. In the next step, the pipes were called in WATERGEMS and then we continue the operation by the allocation of elevation digits to the pipes. Since the topography of this city is very specific and unique, the number of pressure zones was increased. Three zones created only covers about 20% of the population in the city. In this dissertation, the design was performed on the city's main zone with the largest density in the Figures 1,320-1,340. In the next step, the network triangulation was conducted. Finally, the Debiw as allocated based on the triangulation conducted and considering the density of the city for year of horizon. Ultimately, the network of Marivan was designed and calibrated according to hydraulic criteria and pressure zoning. The output of this model can be used in water-supply projects, improvement and reform of the existing net-work in the city, and various other studies. Numerous and various graphs obtained in different parts of a network modelled can be used in the analysis of critical situation, leakage.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.6
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• pp.41-52
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• 2007

Earthquake time-history analyses have been carried out for a buried gas pipeline of X65 which is of popular use in Korea. Parameters included are shape of a buried gas pipeline, soil characteristics, single and multiple earthquake input ground motions and burial depths. Predicted response of strain and relative displacement are then compared with allowable strain and displacement capacity calculated by Guidelines for the Seismic Design of Buried Gas Pipelines, KOGAS. Comparative studies show that strains are in general affected by the burial depths together with change of soil conditions. Regarding the relative displacement, while axial relative displacement is not influenced by the burial depths, transverse relative displacement is affected by both burial depths as well as soil conditions. In all, the current study is encouraged to give a useful information for healthy earthquake evaluation of a buried pipeline.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.937-957
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• 2017

Urban roads are not only congested with vehicles and pedestrians, but also have many pipelines buried to provide convenience for inhabitants. In addition, urban inhabitants live comfortably in buildings adjacent to the road for residence, business, commerce, rest and so on. Therefore, despite the high cost of land, urban underground buildings with high land use efficiency are constantly being built. Recently, the construction of underground buildings has caused social problems such as the collapse of surrounding roads and adjacent buildings. Institutional improvement is being actively carried out to improve this. In this study, a new type of MSRC diaphragm wall was developed and a study on the construction method of underground building was carried out. It is intended to secure the underground excavation safety of underground buildings in urban areas and effectively prevent land subsidence complaints. Also, a reasonable design method of MSRC diaphragm walls using the ultimate strength design method is presented through the flexural performance Experiment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1697-1703
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• 2010

Hydraulic hoses are used as pipelines for transferring power from hydraulic systems in various machineries such as construction equipments, automobiles, and aircraft. Hydraulic hoses protect the system from vibration or impacts, and they are being used to transfer energy in all segments of the industry. In order to protect the system from various external environmental conditions, hydraulic hose assemblies must be able to withstand a wide range of temperatures and pressures, as well as variations in other factors. In previous studies, an acceleration model for the hydraulic hose assembly was developed by taking into account only one of the acceleration factors (temperature or pressure). Therefore, the objective of this study is to develop a comprehensive acceleration model that takes both temperature and pressure into consideration.