• Nuclear Engineering and Technology
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• 제40권1호
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• pp.49-68
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• 2008

The purpose of this paper is to extensively review the condition monitoring (CM) techniques using empirical models in an effort to reduce or eliminate unexpected downtimes in general industry, and to illustrate the feasibility of applying them to the nuclear industry. CM provides on-time warnings of system states to enable the optimal scheduling of maintenance and, ultimately, plant uptime is maximized. Currently, most maintenance processes tend to be either reactive, or part of scheduled, or preventive maintenance. Such maintenance is being increasingly reported as a poor practice for two reasons: first, the component does not necessarily require maintenance, thus the maintenance cost is wasted, and secondly, failure catalysts are introduced into properly working components, which is worse. This paper first summarizes the technical aspects of CM including state estimation and state monitoring. The mathematical background of CM is mature enough even for commercial use in the nuclear industry. Considering the current computational capabilities of CM, its application is not limited by technical difficulties, but by a lack of desire on the part of industry to implement it. For practical applications in the nuclear industry, it may be more important to clarify and quantify the negative impact of unexpected outcomes or failures in CM than it is to investigate its advantages. In other words, while issues regarding accuracy have been targeted to date, the concerns regarding robustness should now be concentrated on. Standardizing the anticipated failures and the possibly harsh operating conditions, and then evaluating the impact of the proposed CM under those conditions may be necessary. In order to make the CM techniques practical for the nuclear industry in the future, it is recommended that a prototype CM system be applied to a secondary system in which most of the components are non-safety grade. Recently, many activities to enhance the safety and efficiency of the secondary system have been encouraged. With the application of CM to nuclear power plants, it is expected to increase profit while addressing safety and economic issues.

• 해양환경안전학회지
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• 제28권2호
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• pp.361-369
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• 2022

강화되는 환경규제에 대응하기 위해서 세계 각국이 수소 경제로의 전환을 본격화하고 있으며, 이에 중장기적으로 수소의 국가간 물동량도 증가할 것으로 예상된다. 국가간 수소의 거래는 수출국의 신재생 에너지 자원과 수입국의 수소 사용 형태, 기술 성숙도 등을 고려하여 암모니아, 액화수소, LOHC 등의 형태로 이루어질 것이나, 어느 한 가지 형태로만 거래되지는 않을 것이다. 액화수소 대비 암모니아와 LOHC의 해상운송은 상대적으로 성숙한 기술임에 본 글에서는 향후 액화수소 운반선 개발을 위하여 필요한 세부 기술들의 식별 및 다양한 기술적 대안들을 통해 가능한 설계안을 확보하면서, 그에 따른 기술적 타당성을 분석하였다.

• 토지주택연구
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• 제15권2호
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• pp.19-28
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• 2024

본 연구는 탄소중립건물의 기술적 정의 및 사례 분석을 통해 탄소중립 달성의 잠재성을 분석한다. 2015년 12월 파리 협정에 따라 세계는 평균 기온 상승을 2℃ 이하로 제한하고, 산업화 이전 수준보다 1.5℃로 제한하려는 노력을 추진하기로 합의하였다. 이를 위해 2050년까지 넷제로(net-zero) 상태에 도달해야 하며, 에너지, 토지, 수송 등 광범위한 부문에서 전환이 필요하다. 본 연구는 탄소중립을 달성하기 위한 기술적 접근과 실제 사례를 통해 탄소중립건물의 가능성과 한계를 탐구하며, 이를 통해 미래의 탄소중립 목표 설정에 기여하고자 한다. 특히, 탄소중립 건물의 정의와 그 실현을 위한 다양한 기술적 방안을 소개하고, 이를 실현한 국내외 사례를 분석함으로써 탄소중립 건물의 효과와 실행 가능성을 평가한다. 연구 결과는 탄소중립 건물의 설계, 건설 및 운영에 대한 구체적 가이드라인을 위한 정보를 제공하며, 정책 입안자와 실무자들이 지속 가능한 건축 환경을 조성하는 데 필요한 실질적 정보를 제공한다.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.167-179
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• 2024

This study explores the feasibility of employing (U, Th)-based accident tolerant fuels (ATFs), specifically (_0.8UO₂, _0.2ThO₂), (_0.8UN, _0.2ThN), and (_0.8UC, _0.2ThC). The investigation assesses the overall performance of these proposed fuel materials in comparison to the conventional UO₂, focusing on deep neutronic and thermal-hydraulic (Th) analyses. Neutronic analysis utilized the MCNPX code, while COMSOL Multiphysics was employed for thermal-hydraulic analysis. The primary objective of this research is to overcome the limitations associated with traditional UO₂ fuel by exploring alternative fuel materials that offer advantages in terms of abundance and potential improvements in performance and safety. Given the limited abundance of UO₂, long-term sustainable nuclear energy production faces challenges. From a neutronic standpoint, the U-Th based fuels demonstrated remarkable fuel cycle lengths, except (_0.8UN, _0.2ThN), which exhibited the minimum fuel cycle length and, consequently, the lowest fuel burn-up. Regarding thermal-hydraulic performance, (_0.8UN, _0.2ThN) exhibited outstanding performance with significant margins against fuel melting compared to the other materials. Overall, when considering the integrated performance, the most favourable results were obtained with the use of the (_0.8UC, _0.2ThC) fuel configurations. This study contributes valuable insights into the potential benefits of (U, Th)-based ATFs as a promising avenue for enhanced nuclear fuel performance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.775-789
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• 2011

Centering on KTX stations, Korea is implementing specialized development of metropolitan business zones nationwide and is in the process of building the transfer link system of transportation in order to actualize intermodalism nationwide. Daejeon station, hub of high-speed railway requires the effective transportation transfer system considering Daejeon station area reorganization plan and opening of second phase high-speed railway. Based on the analysis of the possibility and validity of building a transit center under the Transportation System Efficiency Act, it is necessary to make a mutual benefit in a regional development by installing the resonable transfer system between railway and other transportation services. Through analysis of current situations and technical, economic and environmental feasibility evaluation, design plan of effective transportation transfer system in Daejeon station is proposed.

• ETRI Journal
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• 제31권5호
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• pp.489-499
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• 2009

This paper focuses on assessment and design of transmission systems for distribution of digital signals over standard Category-7A copper cables at speeds beyond 10 Gbps. The main contribution of this paper is on the technical feasibility and system design for data rates of 40 Gbps and 100 Gbps over copper. Based on capacity analysis and rate optimization algorithms, system parameters are obtained and the design implementation trade-offs are discussed. Our simulation results confirm that with the aid of a decision-feedback equalizer and powerful coding techniques, namely, TCM or LDPC code, 40 Gbps transmission is feasible over 50 m of CAT-7A copper cable. These results also indicate that 100 Gbps transmission can be achieved over 15 m cables.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.145-148
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• 1996

In moving object tracking based on the visual sensory feedback, a prerequisite is to determine which feature or which object is to be tracked and then the feature or the object identification precedes the tracking. In this paper, we focus on the object identification not image feature identification. The target identification is realized by finding out corresponding line segments to the hypothesized model segments of the target. The key idea is the combination of the Mahalanobis distance with the geometrica relationship between model segments and extracted line segments. We demonstrate the robustness and feasibility of the proposed target identification algorithm by a moving vehicle identification and tracking in the video traffic surveillance system over images of a road scene.

• 유통과학연구
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• 제2권2호
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• pp.109-118
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• 2004

The number of business incubator (BI), introduced in Korea in the early 90's, has grown rapidly in the last 10 years, reaching 342 by 2002. Most of the incubator was supported financially by the Small and Medium Business Administration (SMBA), and 83% of them are run by college or university. To develop successful plans for college business incubator, we studied the relationship between a college incubator and its tenants through a systematic questionnaire, and compared royalty systems of four college BI's. It was found out that the tenants wants more flexible advisor system and closer relationship with the professors to solve the technical difficulties. The royalty system is important for BI's to survive without the financial assistance from the government, but the royalty systems of the four college BI's studied in this report have some practical shortcomings and needs amendments.

• 한국전기전자재료학회논문지
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• 제28권7호
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• pp.462-466
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• 2015

In this paper, we investigated the relations between dispersion of CNTs (carbon nanotubes) and electrical conductivity in the CNT/PVDF (polyvinylidene fluoride) composite film. By adding hydrophobic CNTs as filler into the PVDF matrix, we fabricated hydrophobic and electrically conducting polymer coating film. Dispersion of CNTs in the CNT/PVDF composite film plays a significant role in terms of electrical conductivity and wetting property. Spray coating method was used to form the CNT/PVDF composite films by injecting the dispersed CNTs in the PVDF solution with different weight ratios from 0.7 wt% to 7 wt%. We investigated the electrical properties and contact angles of the CNT/PVDF composite films with the CNT concentration. Finally we discussed the conducting mechanism and feasibility of the CNT/PVDF composite film for the conducting polymer films.

• 한국정밀공학회지
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• 제19권11호
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• pp.65-74
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• 2002

This paper examines the usefulness of a Brake Steer System (BSS), which uses differential brake forces for steering intervention in the context of Intelligent Transportation Systems (ITS). In order to help the car to turn, a yaw moment can be achieved by altering the left/right and front/rear brake distribution. This resulting yaw moment on the vehicle affects lateral position thereby providing a limited steering function. The steering function achieved through BSS can then be used to control lateral position in an unintended road departure system. A 8-DOF nonlinear vehicle model including STI tire model will be validated using the equations of motion of the vehicle. Then a controller will be developed. This controller, which will be a PID controller tuned by Ziegler-Nichols, will be designed to explore BSS feasibility by modifying the brake distribution through the control of the yaw rate of the vehicle.