• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.8
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• pp.72-78
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• 2022

Bending using high-frequency induction heating is used to bend pipes and sections, and is currently widely applied in industrial fields such as power generation facilities, ships, onshore plants, and offshore plants. The purpose of this study is to study the manufacturing process and design technology of high-frequency bending of pipe to make the best pipe design arrangement. Although various studies are being conducted in the field of high-frequency bending, more research is needed on high-frequency bending of pipes for ship building and offshore plants. The purpose of this study is to review the feasibility of production design using 3D model tool of S3D and AM(PDMS), and to review and improve bending thickness reduction, reduction rate, and roundness.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.137-143
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• 2022

Composite materials, being light-weight and of high mechanical strength, are increasingly used in various industries such as the aerospace, automobile, sporting-goods manufacturing, and ship-building industries. Recently, manufacturing of composite materials using 3D printers has increased. 3D-printed composite materials are made in free-form and adapted for end-use by adjusting the fiber content and orientation. However, research on the machining of 3D printed composite materials is limited. The aim of this study is to develop a machine learning method to select machining conditions for machining of 3D-printed composite materials. The composite material was composed of Onyx and carbon fibers and stacked sequentially. The experiments were performed using the following machining conditions: spindle speed, feed rate, depth of cut, and machining direction. Cutting forces of the different machining conditions were measured by milling the composite materials. PCA, a method of machine learning, was developed to select the machining conditions and will be used in subsequent experiments under various machining conditions.

• Journal of the Korea Safety Management & Science
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• v.25 no.1
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• pp.23-29
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• 2023

Among the Additive Manufacturing (AM) technologies, the Binder-Jetting printing technology is a method of spraying an adhesive on the surface of powder and laminate layer by layer. Recently, this technique has become a major issue in the production of large casting products such as ship-building, custom vehicles and so on. In this study, we performed research to make actual mold castings and increase mechanical property by using special sand and water-based binders. For use as a mold, it has a strength of more than 3MPa and permeability. Various experiments were carried out to obtain suitable them. The major process parameters were binder jetting volume, binder types, layer thickness and heat treatment condition. As a result of this study, the binder drop quantity was measured to be about 60 pico-liter, layer thickness was 100㎛ and the heat treatment condition was measured about 1,000℃ and compressive strength were measured to be more than 5MPa. The optimum condition of this experiment was established through actual casting of aluminum. The equipment used in this study was a Freeforms T400 model (SFS Co., Ltd.), and the printing area of 420 * 300 * 250mm and resolution of 600dpi can be realized.

• Strategy21
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• s.30
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• pp.200-235
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• 2012

Over the past few years, due to the climate change of the earth, the Arctic's sea ice cover is undergoing a historic transformation - thinning, extent reduction in all seasons, and mitigation in the area of multi-year ice in the central Arctic Ocean. These changes allow for increases in maritime access throughout the Arctic Ocean and for potential longer seasons of navigation and possibly transarctic voyage in the summer. These changes also allow more exploration for oil, gas, and other minerals. The Arctic is now an archetype of the complex, multi-dimensional global problems of the twenty-first century. Military security, environmental security, and economic security interact. The potentially enormous economic stakes, sufficient to change the strategic balance among the states of the region, set off competitive pressures for national advantage. Korea, which is heavily dependent upon the sea lane in terms of transportation of its exports and imports, is very much interested in the Arctic sea routes. Korea believes that the Artic sea route, particularly the Northern Sea Route (NSR), could serve as a new useful sea lane, which will enable shorter times between East Asia and Europe, thus resulting in substantial cost saving for ship operators. In addition to shipping, Korea is interested in other Arctic-related maritime industries. Korea, as a leading shipbuilder in the global market, is interested in building ice breakers, drill ships, and other vessels which can contribute to safe operation in Arctic resource development and exploration. Korea, as one of the future stakeholders in Arctic maritime activities, should be ready to foster international cooperation in the region.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.132-137
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• 2015

A modular construction method includes factory-prefabricated room-sized volumetric units. Although low-rise buildings have been constructed worldwide using this method for more than 30 years, it is a relatively new technology in high-rise construction. There are three basic methods of constructing high-rise buildings using modular construction: the core method, the core-and-podium combination method, and the modular in-fill method. While the first two have been used in the USA and in several European countries, the third method, introduced in 2011 by an international cruise ship development firm, is a rather new approach for which there are few case histories. Therefore, its applicability and construction feasibility should be verified. As a pilot study to test the applicability of the modular in-fill method, a 12-story residential building was built in Korea. This paper describes a case study of the pilot project. The advantages and disadvantages of the method and its applicability in terms of cost effectiveness and construction schedule management were evaluated.

• Korea Trade Review
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• v.47 no.6
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• pp.39-53
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• 2022

This study conducted a conformity review of Korean shipping industry policy and suggested that the Korean five-year shipping reconstruction policy has not violated the WTO (World Trade Organization) trade law agreement yet. In order to investigate the latest Korean shipping policy, domestic and foreign reports were reviewed, and after that, the WTO's published data and domestic and foreign journals were analyzed. Through this process, this study tried to review the conformity of trade laws by major Korean shipping policies. The shipping industry is a representative service industry, and subsidies for this are not subject to WTO-level regulation in principle. The purpose of Korean shipping industry policy is to support the shipping industry, a type of service industry, and even if the ship-building and manufacturing industries (shipper) indirectly spread benefits in the process, this is unintentional or private-level support. That is, this study concluded that It is understood that Korea's five-year shipping reconstruction policy does not violate the WTO trade law agreement.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.387-394
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• 2016

Commercial 28 algae removal technologies that have been applied in domestic rivers and lakes with green tide were investigated, analyzed and classified. The classification of algae removal technologies was based on the three criteria (i.e., principle, flow rate of water body, and application period). Also, algae removal technologies were evaluated in terms of cost effectiveness, field applicability, effect durability, and eco friendliness. From the analysis results, technologies using physical, chemical, biological, and convergent controls were 32.2%, 25%, 21.4%, and 21.4%, respectively. The 75% of technologies have been applied to stagnant water body (${\leq}0.2m/s$). Also, algae harvesting ship with dissolved air flotation, conveyor belt and filtration processes and natural floating coagulant were found to have better field applicability, compared to other technologies. However, proper algae removal technology in specific rivers and lakes should be chosen after the evaluation of long-term pilot scale field test. Also, development of energy and resource recovery technologies from algae biomass is warranted.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.37 no.3
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• pp.83-92
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• 2019

This study aims to examine at the garden characteristics of salt merchant in Yangzhou, China during the Ming and Qing Dynasties, I looked at the background of garden formation through the literature. In addition, analyzed the garden design method and components of salt merchants. The results were as follows; First, the Yangzhou area in the past has achieved cultural and economic development with the establishment of the ancient Grand Canal. Salt merchants accumulated wealth through trade, and created many gardens under the background of securing materials for create garden through trade, forming political forces through the cultivation of students, and inflow of foreign cultures. Second, salt merchants in Yangzhou asked garden experts to design and create the garden as a place for exchange and relaxation. Also, through the production of landscape changes using Gasan(假山) and a long corridor(長廊), clear classification of spaces using architectural elements, and the placement of buildings in scenic areas adjacent to the water, the gardens with practical and aesthetic functions were owned. Third, the gardens of Yangzhou Salt Merchants have a building-oriented commercial space on the front, and a garden-centered design characteristic on the back. The garden of the commercial zone was built in a simple form using pots, oddly shaped stone, bamboo and fence patterns in the remained space, focusing on the front of the building. The garden at the back formed a curved waterway connected to the canal is refracted across the garden. The garden also features piled stones(疊石), stone bridges and ship-shaped stone building(石舫). In addition, the design reflected the introduction of trees that take into account the climate and color contrast of Yangzhou province, pavement of various materials and patterns.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.18-23
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• 2017

The shipyard quay process struggles to control workers and maintain a secure working environment because of the presence of at least 1,000 people. Therefore, safety accidents such as an explosion or a fire are likely to occur. With the recent increase in safety accidents at shipyards, the requirements for safety and process monitoring have been strengthened. Major shipyards are conducting researchto monitor the process in real time and to detect the work environment for safety. In this paper, we propose a safe and accurate evacuation route based on the information of the dangerous area and the user's location based on a mobile application to reduce the casualty accidents in the presence of many personnel in a concentrated area. To do this, we analyze the trend of the fire escape system on the ground building, compare various algorithms for escape route calculation, select appropriate algorithms for this study, and perform programming. A basic experiment was conducted to confirm the results. The proposed method is expected to be used in large ship construction sites, passenger ships and large public facilities to reduce accidents in the case of a safety accident.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.98-106
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• 2020

This study examined the integrity of diesel engines for underwater vessels through failure analysis, analyzed the causes of abnormal diesel engine stoppage during building and examined the integrity of secondary damages. The diesel engine stoppage was analyzed by checking the temperature change of the piston before and after the abnormality and checking the damage. In addition, in order to analyze the secondary damage caused by the explosion, the tensile and compressive stresses transmitted to the crankshaft, the core part of the diesel engine, were calculated, and the stress distribution was examined through finite element analysis, but the crankshaft was designed by safety. It was confirmed that there was no damage to the crankcase even when the diesel engine was taken out of the ship and closely inspected. The integrity of the crank shaft was verified in advance for the occurrence of diesel engine emergency shutdown accidents through this research result. Therefore, the inspection and restoration were carried out to the minimum extent, and the quality of diesel engines was secured. This study is expected to be used as a reference for ensuring soundness in any future review of diesel engine quality problems.