• International Journal of Railway
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• v.8 no.1
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• pp.30-34
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• 2015

The Maglev(UTM-02) project is leading by Korea Institute of Machinery & Materials and financially supported from the ministry of Commerce, Industry and Energy. The early development stagy of Maglev(UTM-02) was adopted the general urban railway pneumatic brake system due to the Korea domestic industrial environment. Currently there is two commercial operation Light Railway Train(LRT) system in Korea. One is U-Line in Uijungbu, and the other is Everline in Yongin. Both LRT systems are adopting high performance light weight hydraulic brake system. But those design and manufacturing core technology of the brake system is came from a major brake system companies located from aboard. Currently various studies have been continued to increase practical application and to improve competitiveness on performance for each sub-system of Maglev. Also in case of brake system, developing competitive hydraulic brake system is required. In this study, we have introduced the development process and performance evaluation of the new hydraulic brake system of Maglev.

• Structural Engineering and Mechanics
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• v.70 no.5
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• pp.591-600
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• 2019

Steel tubular buckling controlled braces are well known as being simple, practical and cost-effective lateral force resisting systems. Although these system features have gained the attention of the researchers over the last decade, steel tubular buckling controlled braces currently have limited application. Indeed, only a few steel tubes tightly encased within each other exist in the steel industry. In this paper, a new and practical design method is proposed in order to better promote the widespeared application for current steel tubular buckling controlled brace applications. In order to reach this goal, a holed-adapter made with polyoxymethylene adaptable to all round and square steel sections, was developed to use as infiller. The research program presents designing, producing and displacement controlled cyclic loading tests of a conventional tubular brace and a buckling controlled composite brace. In addition, numerical analysis was carried out to compare the experimental results. As a result of the experimental studies, buckling was controlled up to 0.88 % drift ratio and the energy dissipation capacity of the conventional tubular brace increased 1.46 times due to the proposed design. The main conclusion of this research is that polyoxymethylene is a highly suitable material for the production of steel tubular buckling controlled braces.

• Computers and Concrete
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• v.30 no.2
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• pp.151-164
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• 2022

This paper investigates the stability of the functionally graded cylindrical small-scale tube regarding the dynamic analysis and based on the modified nonclassical high-order nonlocal strain gradient theory. The nonlocal beam is modeled according to the high-order tube theory utilizing the energy method based on the Hamilton principle, then the nonlocal governing equations and also nonlocal boundary conditions equations are obtained. The tube structure is made of the new class of composite material composed of ceramic and metal phases as the functionally graded structures. The functionally graded (FG) tube structures rotate around the central axis, and the stability of this nanodevice is due to the centrifugal force which is used for the application of nanoelectromechanical systems (NEMS) is studied in detail.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.683-685
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• 2022

By comparing the status quo of recycling of new energy vehicles and waste power batteries at home and abroad, analyze the central relationship between recycling of waste power batteries and the interaction between various factors in China, consider the characteristics of blockchain technology, organically integrate into the reverse recycling network, and quantify the relevant factors. Make use of the constructed model to simulate, forecast, and compare and analyze whether to adopt blockchain technology and, on this basis, analyze the intrinsic relationship between various variables. To explore the different effects brought by changing different countermeasures according to different subjects, and expand it to the factor analysis in the whole reverse recycling supply chain to help the government and operators and enterprises to make more objective and scientific decisions, to provide a particular reference for promoting the recycling of waste power batteries and the development of power battery manufacturing industry in China.

• Progress in Superconductivity
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• v.5 no.1
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• pp.1-4
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• 2003

A five-year project for Nb-based single flux quantum (SFQ) circuits supported by Japan's Ministry of Economy Trade and Industry (METI) in Japan was started in September 2002. Since April 2003, the New Energy and Industrial Technology Development Organization (NEDO) has supported this Superconductor Network Device Project. The aim of the project is to improve the integration level of Nb-based SFQ circuits to several ten thousand Josephson junctions, in comparison with their starting integration level of only a few thousand junctions. Actual targets are a 20 GHz dual processor module for the servers and a 0.96 Tbps switch module for the routers. Starting in April 2003, the Nb project was merged with SFQ circuit research using a high-T$_{c}$ superconductor (HTS). The HTS research targets are a wide-band AD converter for mobile-phone base stations and a sampling oscilloscope for wide-band waveform measurements.

• Korean Journal of Construction Engineering and Management
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• v.13 no.6
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• pp.3-12
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• 2012

The slowdown of private building industry resulted in growth of remodeling market as a way to improve energy performance. Remodeling is considered more cost-effective and eco-friendly approach for energy efficient building than new construction. Since 2008, Seoul has promoted Building Retrofit Project (BRP) preponderantly to attract energy-saving renovation by supporting building owners to switch building system into energy-saving system when they remodel their old buildings. According to 2012 press release, 254 Private sectors participated in this green building project and annually reduced 41000ton of greenhouse gas emission, 14000TOE, which also result in 7.5 billion won energy cost savings per year. The paper focuses on the building envelope remodeling as a way to improve energy efficiency. Different components of the building envelope such as wall insulation, window, and shading, were applied to the baseline model and the comparison was analyzed to come up with the ideal solution. This study only assesses the building envelope as to suggest the way to redesign the better energy performing building. Offering solution focusing on the architectural feature is essential because it will provide basic information and standard when remodeling a building for energy efficiency, especially, for the nonresidential buildings used as rental offices.

• Analyses & Alternatives
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• v.5 no.2
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• pp.77-105
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• 2021

Natural gas consumption in Asia is growing at fast tempo because of various factors such as economic growth in the region, urbanization, coal-to-gas switch at power and industry sector. Due to geographical characteristics and lack of international pipeline connections between countries in the continent, majority of natural gas exported to Asian consumers is transported by tankers on the sea in the form of liquefied natural gas. As Asian market is the most lucrative market with the fastest demand growth, the competitions between LNG sellers for market share in Asian market are strengthening. The competitions accelerated, especially after the introduction of large volume of incremental supply into the market by new exporters from the U.S., Australia, and Russia. Cheniere Energy, the first exporter of liquefied natural gas (LNG) in the lower 48 states of U.S. has not adopted the traditional price formation mechanism and business model. Traditionally, prices of long-term LNG contracts have been indexed to the price of competing fuels, such as crude oil. The company adopted a pricing mechanism and business model based on a cost-plus system. Cheniere Energy opted for the safer and the risk-free pricing system, that annually guarantees a fixed amount of revenue to the seller. The company earns the same amount of money, regardless of natural gas price dynamics in the domestic and international market, but possibly with less revenue. However, by introducing and successfully implementing the safer and risk- free business model, Cheniere Energy, a company of a relatively smaller size in comparison with major oil and gas companies, became an example to other smaller-sized companies in the U.S. The company's business model demonstrated how to enter and operate LNG business amid increasing competitions among sellers in the U.S. and international market.

• Journal of the Korean Electrochemical Society
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• v.19 no.2
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• pp.39-44
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• 2016

Oxygen reduction reaction in the fuel cell (ORR) plays a dominant role in the overall reaction. In addition, the low compatibility between the membrane and the binder consisted of different materials, greatly reduces the efficiency of the fuel cell performance. In view of these two problems, geometrically modified copolymers with 9.9_Bis (4-hydroxyphenyl) were synthesized via condensation reaction instead of conventional biphenol and were adopted as hydrocarbon ionomer binders. By utilizing these binders, two kinds of MEAs using fluorinated Nafion membrane and hydrocarbon based membrane were manufactured in order to electrochemical performance evaluation. With current-voltage curves, there was no significant difference in the 0.6 V when two types of membrane were applied. Also, tafel slope became considerably lower as compared to the Nafion membrane. Thus, it is determined that the new hydrocarbon binder is expected to contribute the improvement in performance of fuel cells.

• Korea Trade Review
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• v.43 no.4
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• pp.111-130
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• 2018

In December 2015, the Paris Agreement was adopted to cope with global warming caused by greenhouse gas emission and to prevent the average temperature of the Earth from rising. Renewable energy sources have become important to address environmental problems such as rising sea levels, depletion of forests and fine dust. In order to grow renewable energy, government support is needed. However, excessive government support for the renewable energy industry could pose problems that include undermining fair competition and raising costs. The WTO already has heard cases involving renewable energy subsidies. This article focuses on subsidies and countervailing tariffs as well as examines WTO disputes related to renewable subsidies, and also analyze legal issues that are problematic in granting subsidies for the development of new renewable energy industries. In WTO dispute involving renewable energy subsidies, legal issues are SCM Agreement article 2 Specificity, article 3 (b) import substitution subsidy and GATT article 20. This paper proposes improvement measures such as the reintroduction of article 8 Non-Actionable Subsidies or special provisions on energy subsidy. In addition, it is necessary to clarify the interpretation of Article 3 of the subsidy agreement. However, excessive government subsidies can lead to trade friction, so the WTO rules should be improved in line with the WTO goals of environmental protection, equity in free trade, and sustainable development.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1705-1711
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• 1991

On-line fault detection and diagnosis has an increasing interest in a chemical process industry, especially for a process control and automation. The chemical process needs an intelligent operation-aided workstation which can do such tasks as process monitoring, fault detection, fault diagnosis and action guidance in semiautomatic mode. These tasks can increase the performance of a process operation and give merits in economics, safety and reliability. Aiming these tasks, series of researches have been done in our lab. Main results from these researches are building appropriate knowledge representation models and a diagnosis mechanism for fault detection and diagnosis in a chemical process. The knowledge representation schemes developed in our previous research, the symptom tree model and the fault-consequence digraph, showed the effectiveness and the usefulness in a real-time application, of the process diagnosis, especially in large and complex plants. However in our previous approach, the diagnosis speed is its demerit in spite of its merits of high resolution, mainly due to using two knowledge models complementarily. In our current study, new knowledge representation scheme is developed which integrates the previous two knowledge models, the symptom tree and the fault-consequence digraph, into one. This new model is constructed using a material balance, energy balance, momentum balance and equipment constraints. Controller related constraints are included in this new model, which possesses merits of the two previous models. This new integrated model will be tested and verified by the real-time application in a BTX process or a crude unit process. The reliability and flexibility will be greatly enhanced compared to the previous model in spite of the low diagnosis speed. Nexpert Object for the expert system shell and SUN4 workstation for the hardware platform are used. TCP/IP for a communication protocol and interfacing to a dynamic simulator, SPEEDUP, for a dynamic data generation are being studied.