• 한국정보과학회논문지:시스템및이론
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• 제35권7호
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• pp.354-360
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• 2008

최신의 마이크로프로세서 설계에서는 전력 관련 문제들이 중요한 고려사항이 되었다. 온-칩(On-chip) 온도 상승은 이와 관련하여 중요한 요소로 부각되었다. 이를 적절하게 처리하지 않을 경우 냉각 비용과 칩 신뢰성에 부정적인 결과를 초래한다. 이 논문에서 우리는 시간적/공간적인 핫 스폿(Hot spot) 완화를 위한 설계들과 열 시간 상수, 작업부하 변동, 마이크로프로세서의 전력 분배 사이의 보편적인 상충관계(Trade off)들을 조사한다. 우리의 방안은 작업부하의 실행위치/순서를 변경하고 동시실행 스레드의 수를 조절하여 시스템의 공간 및 시간적인 열 틈새(Heat slack)에 영향을 줌으로써, 운영체계(OS)와 이미 시스템에 존재하는 하드웨어의 지원만으로 적절한 시간제한내에 작업부하를 조절함으로써 온-칩 온도를 낮출 수 있다.

• Structural Engineering and Mechanics
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• 제50권1호
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• pp.19-36
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• 2014

This paper focuses on a model order reduction (MOR) for large-scale rotordynamic systems by using finite element discretization. Typical rotor-bearing systems consist of a rotor, built-on parts, and a support system. These systems require careful consideration in their dynamic analysis modeling because they include unsymmetrical stiffness, localized nonproportional damping, and frequency-dependent gyroscopic effects. Because of this complex geometry, the finite element model under consideration may have a very large number of degrees of freedom. Thus, the repeated dynamic analyses used to investigate the critical speeds, stability, and unbalanced response are computationally very expensive to complete within a practical design cycle. In this study, we demonstrate that a Krylov subspace-based MOR via moment matching significantly speeds up the rotordynamic analyses needed to check the whirling frequencies and critical speeds of large rotor systems. This approach is very efficient, because it is possible to repeat the dynamic simulation with the help of a reduced system by changing the operating rotational speed, which can be preserved as a parameter in the process of model reduction. Two examples of rotordynamic systems show that the suggested MOR provides a significant reduction in computational cost for a Campbell diagram analysis, while maintaining accuracy comparable to that of the original systems.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.330-337
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• 2002

The HANARO seismic monitoring system is classified as non-nuclear safety(NNS), seismic category I, and quality class T The seismic monitoring system installed at the instrument room consists of five field sensors and one monitoring cabinet. The field sensors are composed of three triaxial accelerometers which installed at base slab, free field and overhead crane support respectively, a seismic trigger and a seismic switch at base slab. The most parts of analog system except field sensors are not produced any more, the improvement of the system is to be needed. The analog system with magnetic tape recorder is not only out-of-date model but dependent upon foreign technology. So it is difficult to get the spare parts and the cost to buy them is increased. Therefore we have improved the analog seismic monitoring system into a new digital seismic monitoring analysis system(SMAS) except five field sensors. After the installation of the new SMAS, we have carried out the site acceptance test(SAT) to confirm the field functions. The results of SAT satisfy the requirements of the fabrication technical specification. This new SMAS is operating at HANARO instrument room to acquire and analyse the signal of earthquake.

• 통상정보연구
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• 제8권1호
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• pp.125-141
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• 2006

It is no unnecessary to tell the importance of foreign trade in Korea economics. Nevertheless, government's direct support is impossible owing to WTO's regulation. Accordingly, government have brought focus into trade facilitation as paperless trade. e-Trade document repositary building by government's budget and private sector's cooperation is a part of e-Trade platform and necessary function in connection with relay and certification of e-Trade document. This study examined the estimated operational problems of e-Trade document repositary as compared Licensed Electronic Document Repositary. Firstly, the operator of e-Trade document repositary undertake multiple role and function as Licensed Certification Authorities(e-sign Act), Licensed Electronic Document Repositary(Framework Act on Electronic Transaction) etc. Secondly, sufficient levy that meet operating cost of the e-trade document is the key point of e-Trade document repositary's success, because additional budget invest in that operation is too hard to do. Thirdly, the operator of the e-Trade document repositary have to keep fairness, objectivity and transparency because the operational right is exclusive.

• 한국환경과학회지
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• 제29권5호
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• pp.457-468
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• 2020

With continuous industrial development, the types, and amount of particulate matter (PM) have been increasing. Since 2018, environmental standards regarding PM have become more stringent. Pulse air jet bag filters are suitable for PM under the 20 ㎛ and, can function regardless of size, concentration and type. Filtration velocity and shape are important factors in the operation and design of the pulse air jet bag filters however, few established studies support this theory. In this research, numerical simulations were conducted based on experimental values and, several methods were employed for minimizing the pressure drop. In the pilot system, as the inlet duct velocity was faster than 19 m/sec, flow was not distributed equally and, re-entrainment occurred due to the hopper directional vortex. The multi-inlet system decelerated the hopper directional vortex by 25 ~ 30%, thereby decreasing total pressure drop by 6.6 ~ 14.7%. The guide vane system blocked the hopper directional vortex, which resulted optimal vane angle of 53°. The total pressure of the guide vane system increased by 0.5 ~ 3% at 1.5 m/min conditions. However, the filtration pressure drop decreased by 4.8 ~ 12.3% in all conditions, thereby reducing the operating cost of filter bags.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1705-1716
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• 2021

Bangladesh, as a newcomer country, is expecting to start her nuclear power journey by 2022. Due to evident reasons, newcomer nuclear countries face several key challenges concerning the development of national nuclear safety infrastructure. The paper investigates the status of the 7 key safety infrastructure issues out of the 19 and readiness of the supportive organizations, laboratories, and workforces following the International Atomic energy Agency's status evaluation guide at milestone 3 and foreign countries' practice. Much progress has been achieved at phase 3 regarding the establishments of a few Acts, a regulator, and an operator. However, comprehensive regulatory frameworks, skilled workforces, establishments of a few supportive organizations, and laboratories for managing environmental radioactivity, radiological accidents, and radioactive wastes are yet to ready. Several suggestions are made for establishing and expediting radiation monitoring laboratories, a radiological emergency management center, a radioactive waste management company, and technical support organizations for the safety infrastructure. To avoid perceived risks, policymakers and competent authorities need to emphasize creating an optimized safety infrastructure before commissioning and operating the 1^st nuclear power plant safely, securely, and cost-sustainably.

• The Journal of Asian Finance, Economics and Business
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• 제8권4호
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• pp.239-247
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• 2021

Conventional banks are often considered more efficient than Islamic banks because they have been operating for decades, but Islamic banks have shown rapid development recently. Therefore, this study mainly aims to compare the level of efficiency of conventional banks and Islamic banks and which ones have the best level of efficiency. This study employs panel data using Stochastic Frontier Analysis (SFA) as the data analysis technique. The data used is annual data from 13 conventional banks and 13 Islamic banks in Indonesia during the 2014-2019 period. The result shows no significant difference in the efficiency of conventional banks and Islamic banks. This result is presumably influenced by the small size of the bank and the total number of banks used in the study. The data used in the study is limited to the period from 2014 to 2019. The variables utilized are also limited to the availability of financial report data which is publicly published. This study provides additional empirical evidence regarding conventional banks' and Islamic banks' efficiency in Indonesian banking by using the latest data. While theoretically, Islamic banks are expected to be more efficient than conventional banks, this study did not find any strong support for the case in Indonesia during the observation period.

• The Journal of Asian Finance, Economics and Business
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• 제9권4호
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• pp.325-332
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• 2022

This research aims to examine and assess how management methods, financial conditions, and corporate governance strategies affect stock returns. This study employs a quantitative approach with a population of 1968 firms with stock returns (return) and a sample of 225 companies with corporate governance practices in the manufacturing industry in Indonesia from 2013 to 2018. The findings of this study show that strategic management has a significant impact on stock return, financial condition, and corporate governance strategy. The findings of this study on debt strategy as a proxy for management strategy, debt default as a proxy for economic conditions, corporate governance strategy as a proxy for centralized ownership, and independent commissioners function as a mechanism of internal and external control in increasing stock return for investors all support increasing stock return for investors. The cost reduction strategy includes reducing operating costs unless the audit committee has not yet functioned as an internal control or requirement for a company to be listed with the Financial Services Authority on the Indonesia Stock Exchange.

• 해양환경안전학회지
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• 제28권3호
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• pp.441-450
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• 2022

The introduction of autonomous underwater gliders (AUGs) specifically addresses the reduction of operational costs that were previously prohibited with conventional autonomous underwater vehicles (AUVs) using a "scaling-down" design philosophy by utilizing the characteristics of autonomous drifters to far extend operation duration and coverage. Long-duration, wide-area missions raise the cost and complexity of in-water testing for novel approaches to autonomous mission planning. As a result, a simulator that supports the rapid design, development, and testing of autonomy solutions across a wide range using software-in-the-loop simulation at faster-than-real-time speeds becomes critical. This paper describes a faster-than-real-time AUG simulator that can support high-resolution bathymetry for a wide variety of ocean environments, including ocean currents, various sensors, and vehicle dynamics. On top of the de facto standard ROS-Gazebo framework and open-sourced underwater vehicle simulation packages, features specific to AUGs for ocean mapping are developed. For vehicle dynamics, the next-generation hybrid autonomous underwater gliders (Hybrid-AUGs) operate with both the buoyancy engine and the thrusters to improve navigation for bathymetry mappings, e.g., line trajectory, are is implemented since because it can also describe conventional AUGs without the thrusters. The simulation results are validated with experiments while operating at 120 times faster than the real-time.

• 한국멀티미디어학회논문지
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• 제4권1호
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• pp.1-12
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• 2001

EDI는 현재, 기업과 기업간의 거래에서 종이없는 거래를 목표로 상거래 데이터를 전자 문서 형태로 교환하기 위한 새로운 방식으로 이용되고 있다. 그러나 기존의 EDI는 전용 프로토콜에 기반한 폐쇄적이고 복잡한 전자 문서 교환 방식을 채택하고 있으며, EDI에 관련한 법령과 제도가 미비할 뿐만 아니라 이의 도입 및 운영비용이 과다하여 실제로 사용하는 기업의 수가 그렇게 많지 않은 실정이다. 본 논문에서는 이러한 기존의 EDI가 갖는 문제점을 보완하기 위해 코드 형태의 전송 문서를 XML DTD로 표현하여 웹을 통해 비교적 저렴하게 문서를 전달할 수 있도록 하고, 객체지향 데이터베이스를 이용하여 보다 편리하고 효과적으로 정보를 관리하고 검색할 수 있도록 하는 개방형 EDI 문서 정보 관리 시스템(OEIMS: Opened EDI document Information Management system)을 제안한다. 제안된 OEIMS는 기존 시스템들과는 달리 EDI가 갖는 구조의 특성을 모듈식 설계로 다른 시스템에 비해 저장 및 관리에 효율적인 특성을 갖는다.