• 한국정보통신학회논문지
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• 제5권3호
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• pp.493-501
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• 2001

웹 기반의 컴퓨터 기술이 보편화되면서, 정보통신 환경은 클라이언트/서버 시스템에서 e-비지니스 시스템으로 점차 바뀌어 가고 있다. 이러한 e-비지니스 시스템은 데이터베이스와 서버사이드 프로그래밍을 통합하기 위한 웹 인터페이스 기술을 요구하고 있다. 전통적으로 CGI 기술이 웹 인터페이스의 표준으로 사용되어 왔으나 연결의 어려움과 처리에 많은 지연 시간을 발생시켰다. 따라서 이러한 문제점을 개선하기 위해 컴퓨터자원의 사용량을 줄이면서도 빠른 처리가 가능한 ISAPI 방법과 JDBC방법 등이 개발되었다. 본 연구에서는 보다 효과적인 웹 인터페이스 방법을 제안하기 위해 JDBC-ODBC 기법과 ISAPl 확장 기법을 이용한 시스템을 구현하고 구현 방법과 처리시간을 상호 비교한다.

• 한국CDE학회논문집
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• 제3권1호
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• pp.48-56
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• 1998

Finite element analysis is very important in the design and analysis of mechanical engineering. The process of FEA encompasses shape modeling, mesh generation, matrix solving and post-processing. Some of these processes can be tightly integrated with the current software architectures and data sharing mode. However, complete integration of all the FEA process itself and the integration to the manufacturing processes is almost impossible in the current practice. The barriers to this problem are inconsistent data format and the enterprise-wise software integration technology. In this research, the information model based on STEP AP209 was chosen for handling finite element analysis data. The international standard for the FEA data can bridge the gap between design, analysis and manufacturing processes. The STEP-based FEA system can be further tightly integrated to the distributed software and database environment using CORBA technology. The prototype FEA system DICESS is implemented to verify the proposed concepts.

• 한국건설관리학회논문집
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• 제12권2호
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• pp.64-71
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• 2011

건설공사의 규모가 대형화, 복합화 되어감에 따라서 유지관리의 중요성이 더욱 커지고 있다. 유지관리의 효과를 높이기 위해서는 유지관리단계의 정보뿐만 아니라 설계 시공단계에서 생성된 정보를 신속하게 조회하고 활용할 수 있어야 한다. 본 논문에서는 3D 그래픽 모델을 활용한 교량 구조물 유지관리 정보 시스템을 제시한다. 3D 환경의 유지관리 정보 시스템은 시설물 부재의 속성정보를 저장하고, 이와 관련하여 데이터베이스에 저장되어 있는 데이터를 추출함으로써 필요한 자료를 신속하게 조회할 수 있다. 연구의 목적을 달성하기 위해서 캐드와 웹 환경으로 구성된 프로토타입을 개발했다. 개발된 프로토타입을 적용하여 테스트한 결과 유지관리자는 웹 환경에서 사무실과 현장에서 필요한 데이터를 찾을 수 있으며, 작업 시 실시간으로 데이터를 활용하여 유지관리의 시간을 단축하고, 의사결정의 정확성을 높일 수 있는 것으로 나타났다.

• 한국재난관리표준학회지
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• 제2권1호
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• pp.81-89
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• 2009

본 연구에서는 트러스 교량의 표준화된 데이터베이스 구축을 통해 웹 환경에서 정보 공유를 실현하는 정보관리 시스템을 개발하였다. 이를 위해, 형상정보는 STEP에서 제시하는 AP 203을 기반으로 데이터 구조를 구성하여 정보를 저장하였으며, 웹상의 3차원 가시화는 Web 3D 기술을 적용하여 구현함으로써 사용자의 편의를 돕고 구조물에 대한 기하학적인 이해를 용이하게 하였다. 해석정보는 AP 209를 사용하여 유한요소해석모델과 해석결과 및 물성 정보를 관계형 데이터베이스에 저장하였다. 구축된 데이터베이스를 기반으로 트러스 교량의 정보관리를 위한 통합된 시범시스템을 개발하였으며, 개발된 시스템은 시방규정 및 안전점검과 같은 제반정보를 형상객체와 연계하여 사용자에게 제공한다.

• Steel and Composite Structures
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• 제49권1호
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• pp.81-89
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• 2023

A simplified calculation method of natural vibration characteristics of high-speed railway multi-span bridge-longitudinal ballastless track system is proposed. The rail, track slab, base slab, main beam, bearing, pier, cap and pile foundation are taken into account, and the multi-span longitudinal ballastless track-beam-bearing-pier-cap-pile foundation integrated model (MBTIM) is established. The energy equation of each component of the MBTIM based on Timoshenko beam theory is constructed. Using the improved Fourier series, and the Rayleigh-Ritz method and Hamilton principle are combined to obtain the extremum of the total energy function. The simplified calculation formula of the natural vibration frequency of the MBTIM under the influence of vertical and longitudinal vibration is derived and verified by numerical methods. The influence law of the natural vibration frequency of the MBTIM is analyzed considering and not considering the participation of each component of the MBTIM, the damage of the track interlayer component and the stiffness change of each layer component. The results show that the error between the calculation results of the formula and the numerical method in this paper is less than 3%, which verifies the correctness of the method in this paper. The high-order frequency of the MBTIM is significantly affected considering the track, bridge pier, pile soil and pile cap, while considering the influence of pile cap on the low-order and high-order frequency of the MBTIM is large. The influence of component damage such as void beneath slab, mortar debonding and fastener failure on each order frequency of the MBTIM is basically the same, and the influence of component damage less than 10m on the first fourteen order frequency of the MBTIM is small. The bending stiffness of track slab and rail has no obvious influence on the natural frequency of the MBTIM, and the bending stiffness of main beam has influence on the natural frequency of the MBTIM. The bending stiffness of pier and base slab only has obvious influence on the high-order frequency of the MBTIM. The natural vibration characteristics of the MBTIM play an important guiding role in the safety analysis of high-speed train running, the damage detection of track-bridge structure and the seismic design of railway bridge.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2022년도 추계학술대회
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• pp.160-161
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• 2022

Hydrogen is bridge fuel with high energy content and environmentally friendly to satisfy the stringent IMO regulation relating to greenhouse gas (GHG) emissions. There is growing interest in hydrogen in numerous nations and regions illustrated by an extensive range of research and development in technology. Regarding maritime applications, researchers have recognized the utilization of hydrogen as a fuel for fuel cells, a device that converts the chemical energy of the fuel to electrical energy. Solid oxide fuel cell (SOFC), with high working temperature, is easy to combine with the waste heat recovery cycles/devices to increase output power and thermodynamic performances as well. Furthermore, the cold energy from liquid hydrogen supplied to SOFC can also be used to generate more power. In this study, we proposed a SOFC integrated system with the idea of combining the waste heat recovery from the SOFC exhaust stream and cold energy utilization from LH₂. The designation is aimed to target small-scale vessel which uses electric propulsion for short distances voyage.

• Journal of Power Electronics
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• 제11권4호
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• pp.591-598
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• 2011

This paper investigates a power supply of medium voltage with enhanced ignition characteristics for plasma torches. A series resonant half-bridge topology is presented as a suitable ignition circuitry. The ignition circuitry is integrated into the main power conversion system of a multi-phase staggered three-level dc-dc converter with a diode front-end rectifier. A plasma torch rated at 3MW, 2kA and having a physical size of 1m is selected to be the high enthalpy source for a waste disposal system. The steady-state and transient operations of a plasma torch are simulated. The parameters of a Cassie-Mary arc model are calculated based on 3D magneto-hydrodynamic simulations. The circuit simulation waveform shows that the ripple of the arc current can be maintained within ${\pm}10%$ of its rated value under the presence of a load disturbance. This power conversion configuration provides a high enough ignition voltage, around 5KA, during the ignition phase and high arc stability under the existence of arc disturbance noise resulting in a high-performance plasma torch system.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2002년도 춘계학술발표논문집 (하)
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• pp.1203-1206
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• 2002

통합플랫폼 관리체재의 운용에 있어서 승객제어장치를 제어하고 감시하는 공항관리자에게는 공항관련 등의 상황통제시 항상 위험이 존재하고 있다. 비행기에 무인화를 도입하면 인간이 수동적으로 처리해야 하는 부분을 기계로 대체하면 보다 안전하게 되어 여러 위험도를 감소시킬 수 있는 해결책의 하나가 될 수가 있을 것으로 본다. 제안된 방법의 성능을 평가하기 위해, 탑승시스템을 조작하는 제어시스템의 컴퓨터 시뮬레이터를 만들어 수행해 보았다. 본 논문에서는 통합플랫폼 관리체재 하에서 열악한 손상조건에서도 탑승객의 불편을 주지 않고 비행기의 여러 가지 돌발상황에 따른 적절한 조치를 자동적으로 취해주는 마이크로프로세서를 이용한 탑승시스템을 설계하고 구현했다. 제안하는 시스템은 기존 시스템과 비교시 보다 정밀하게 탑승영역활동을 하였고 돌발시에도 비행기가 처한 상황에 따라 보다 적절한 조치를 취할 수가 있었다.

• 디지털융복합연구
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• 제6권3호
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• pp.45-52
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• 2008

For the domestic digital contents, it is particularly important that the planning and mediating functions should cover the whole Industries so that dividends and assistance to reach all the way back to the primary contents-creating level, where economic risks are especially high. A proactive cooperation system or framework between the government, the businesses and research institutions, which would allow for free flow of interaction among these players, can play that role. We can broadly define cooperation frameworks into two; one between the central and the local governments and another among private-sector groups, such as companies, associations and groups. These players in the framework have differing, sometimes, conflicting views regarding the digital contents industry whether the digital contents should aim for skilled applicability or the abstract or whether the emphasis should rest on public interest or profitability. Immature competition and lack of trust among these players also give rise to such inefficiencies as overlap in investments, inexpertness and inefficient use of resources. We have proposed and realized the National Integrated Cooperation System to bridge these gaps among the major players in the industry. The National Integrated Cooperation System rests on the following major functions. The first major function of the NICS is to decipher any ambiguity that may be embedded in external Inputs by stratified role and bias. The second function is to create cooperative groups that will deal with the ambiguities based on its consequent situation. The third is a feedback function that will draw out a new cooperative way by re-feeding the capacities and the conflicts that stem from the existing organizations and strategies into cooperation and adjustment process. Our NICS has compared and evaluated with England and Australia digital content industry models under AHP(Analytic Hierarchy Process) method. NICS has turned out to be well designed and have strong points based on OECD innovation and cooperation criteria.

• 대한인간공학회지
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• 제29권4호
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• pp.673-680
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• 2010

The effects of different auditory warnings on response time and accuracy were studied in a laboratory ship-bridge work environment. Subjective preference on the type of auditory warnings was also of a primary concern. Twenty five subjects were asked to select an appropriate button for the warning sound presented with three types of auditory warning (abstract sound, auditory icon, and voice alarm) and five levels of warning situation (fire, steering failure, collision, engine failure, and low power). Results showed that the response time and accuracy was significantly affected by the types of auditory warning. The voice alarm resulted in a higher accuracy and subjective preference, as compared to the auditory icon and abstract sound. Regarding the response time, auditory icons and voice alarms were equivalent and superior to abstract sounds. Actual or potential applications of this research include guidelines for the design of integrated ship bridge systems.