• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.470-476
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• 2019

The braking force for a train is generally provided by compressed air. The pressure valve system that is used to apply appropriate braking forces to trains has a complex flow circuit. It is possible to make a channel shape that can increase the flow efficiency by 3D printing. There are restrictions on the flow shape design when using general machining. Therefore, in this study, the compressed air flow was analyzed in a pressure valve system by comparing flow paths made with conventional manufacturing methods and 3D printing. An analysis was done to examine the curvature magnitude of the flow path, the diameter of the flow path, the magnitude of the inlet and reservoir pressure, and the initial temperature of the compressed air when the flow direction changes. The minimization of pressure loss and the uniformity of the flow characteristics influenced the braking efficiency. The curvilinear flow path made through 3D printing was advantageous for improving the braking efficiency compared to the rectangular shape manufactured by general machining.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.275-277
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• 2015

This paper proposed have been the business card information to the computer when creating business card printing agency saved to a file, there is always the risk of personal information leakage. Application file organization information into the card, the name, phone number, email address information, such as is capable of easily accessible because it is not encrypted. This paper proposed it encrypts the information entered on the Business Card application file to automate the process of the card application and simplifying the business card application process minimizes the work of staff and linked directly to the print shop how to automatically delete the print file after the completion of business card printing and research.

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.43-48
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• 2021

This study was conducted using FLACS, a specialized gas accident analysis program. Hydrogen refueling stations subject of safety analysis, consist of compression facilities, storage tanks, and hydrogen piping. The safety analysis of potential risk factors was conducted after reflecting the design specifications of major facilities and components, environmental conditions around hydrogen refueling stations, etc. As of 2021, about 70 refueling stations in Korea are available, and 1,200 are scheduled to be introduced in the next 2040. To prepare for possible accidents caused by potential hazards for the safe distribution of hydrogen refueling stations, we intend to derive hydrogen leakage diffusion scenarios and review their safety.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.197-199
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• 2008

정보화 사회의 발전과 인터넷의 급속한 확산으로 인하여 디지털 콘텐츠에 대한 수요 및 생산되는 콘텐츠의 수가 기하급수적으로 증가하고 있다. 그러나 디지털 콘텐츠는 생산 및 수집 시기, 그리고 저장 방법 등에 따라 그 형태가 매우 다양하므로 디지털 콘텐츠를 표준화할 수 있는 방법에 대한 연구가 필요하다. 본 논문에서는 디지털 콘텐츠의 메타데이터 타입을 표준화하기 위한 새로운 메타데이터 타입을 정의한다. 제안하는 메타데이터 타입은 XML 형태로 기술하며 디지털 콘텐츠의 국제 표준 메타데이터인 더블린코어에 기초하여 정의한다. 제안 방법은 더블린코어에서 정의한 주요소에 역할 속성을 추가하여 콘텐츠 생산에 직간접적으로 영향을 준 생산자 정보를 표현할 수 있다. 또한 제안하는 방법은 콘텐츠 생산에 관련된 연관 콘텐츠 정보를 유지함으로써 디지털 콘텐츠 간의 연관 관계를 표현 할 수 있다.

• The Journal of Society for e-Business Studies
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• v.24 no.2
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• pp.199-216
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• 2019

The public SW market is 3 trillion won, which is less than 10% of the total SW market. However, due to the nature of the domestic market, it is an important market with a relatively large impact on small and medium-sized software companies. In this market, government is operating the Public SW Project Demand Forecasting System in order to support the marketing activities of small and medium sized SW companies and establish a fair market order. The current system has limitations such as lack of user convenience, insufficient analysis capability and less business connection. This study was conducted to identify the problems of these systems and to propose a new system for improving the convenience of users and expanding the information utilization of SMEs. To this end, we analyzed the requirements of each stakeholder. We proposed the 2-phased forecasting cycle, the management cycle, and the system life cycle of public SW projects and created a unified identifier (UID) so that the information of those projects can be identified and linked among them. As a result, an integrated reference model of project information management based on system life cycle was developed, which can explain the demand forecasting and project information, and the improved processes was also designed to implement them. Through the result of this study, it is expected that integrated management of public SW projects will be possible.

• Journal of KIISE:Databases
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• v.34 no.2
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• pp.109-118
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• 2007

Recently, flash memory is used to store data in mobile computing devices such as PDAs, SmartCards, mobile phones and MP3 players. These devices need index structures like the B-tree to efficiently support some operations like insertion, deletion and search. The BFTL(B-tree Flash Translation Layer) technique was first introduced which is for implementing the B-tree on flash memory. Flash memory has characteristics that a write operation is more costly than a read operation and an overwrite operation is impossible. Therefore, the BFTL method focuses on minimizing the number of write operations resulting from building the B-tree. However, we indicate in this paper that there are many rooms of improving the performance of the I/O cost in building the B-tree using this method and it is not practical since it increases highly the usage of the SRAM memory storage. In this paper, we propose a BOF(the B-tree On Flash memory) approach for implementing the B-tree on flash memory efficiently. The core of this approach is to store index units belonging to the same B-tree node to the same sector on flash memory in case of the replacement of the buffer used to build the B-tree. In this paper, we show that our BOF technique outperforms the BFTL or other techniques.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.143-150
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• 2013

The purpose of this study is to suggest the methodology to develop variable-scale network model, which is able to induce large-scale road network in detailed level corresponding to small-scale linear objects with various abstraction in higher level. For this purpose, the definition of terms, the benefits and the specific procedures related with a variable-scale model were examined. Second, representation level and the components of layer to design the variable-scale map were presented. In addition, rule-based data generating method and indexing structure for higher LoD were defined. Finally, the implementation and verification of the model were performed to road network in study area (Jeju -do) so that the proposed algorithm can be practical. That is, generated variable scale road network were saved and managed in spatial database (Oracle Spatial) and performance analysis were carried out for the effectiveness and feasibility of the model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1225-1234
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• 2013

According to the importance of greenhouse gas emissions, it grows day by day, the goverment is promoting to prepare the specific policy implementation to enhance building energy-saving design standars as the development agenda. In this study, the statistical analysis was performed by Descriptive statistics, Regression analysis, and Hypothesis testing to collect to generate and storage energy usage data in real time to settle parameter setting to affect energy consumption under energy-guzzling apartment not single building. This study is expected to be utilized as the basis for the optimum energy-saving design of the future of the building or facility energy costs rise and the demand for energy-efficient and stable management.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.34-50
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• 2022

Since the Paris climate agreement, reducing greenhouse gases has been the most important global issue. In particular, it is necessary to reduce fossil fuels in the mobility sector, which accounts for a significant portion of total greenhouse gas emissions. In this paper, we investigated the economic feasibility of green mobility energy supply chains, which supply hydrogen as fuel to hydrogen vehicles based on electricity from renewable energy sources. The design and operation costs were analyzed by evaluating nine scenarios representing various combinatorial possibilities such as renewable energy generation, hydrogen production through water electrolytes, hydrogen storage and hydrogen refueling stations. Simulation calculations were made using Homer Pro, widely used commercial software in the field. The experience gained in this study could be further utilized to construct actual hydrogen energy systems.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.130.2-130.2
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• 2010

2020년까지 대형 CCS (Carbon Capture and Storage) Demo Plant 시장 (100MW 이상) 이 형성될 전망이다. 발전 부문에서 대규모 CCS 실증 프로젝트는 총 44개이며 연소전(41%), 연소후(28%), 순산소(3%) 프로젝트가 계획되어 있다. 순산소 연소 기술은 실증진입단계, 연소후(USC) 기술은 상용화 추진단계, 연소전 (IGCC) 기술은 실증완료 이후 상용화 진입 단계이다. IGCC 발전의 석탄가스화 기술은 타 산업분야에 서 상용화 되어있어 기술신뢰성이 높다. IGCC 단위설비 기술 개발을 통한 성능개선 및 비용절감에 대한 잠재력을 가지고 있기 때문에 미래의 석탄발전기술로 고려되고 있다. IGCC 기술은 가장 상용화에 앞서있지만 아직까지 IGCC+CCS 대형 설비가 운전된 사례가 전 세계적으로 없으며 미국 EPRI 등에서 Feasibility Study 단계이다. 현재 국책과제로 수행중인 300MW급 태안 IGCC 플랜트를 대상으로 향후 CCS 설비를 적용했을 경우에 대해 기술 타당성 검증을 목적으로 IGCC+CCS 모델링을 수행하였다. 모델링은 스크러버 후단의 합성 가스를 대상으로 하였다. Water Gas Shift Reaction (WGSR) 공정 및 Selexol 공정을 구성하여 최종 단에서 수소 연료를 생산할 수 있도록 하였다. WGSR 공정은 Co/Mo 촉매반응기로 구성되었다. WGSR 모델링을 통하여 주입되는 스팀량 (1~2 mol-steam/mol-CO) 및 온도 변화 ($220-550^{\circ}C$)에 따른 CO가스의 전환율을 분석하여 경제적인 설계조건을 선정하였다. Selexol 공정은 $H_2S$ Absorber, $H_2S$ Stripper, $CO_2$ Absorber, $CO_2$ Flash Drum으로 구성된다. Selexol 공정의 $CO_2$와 $H_2S$ 선택도를 분석 하였으며 단위 설비별 설계 조건을 예측하였다. 모델링 결과 59kg/s의 합성가스($137^{\circ}C$, 41bar, 가스 조성은 $CO_2$ 1.2%, CO 57.2%, $H_2$ 23.2%, $H_2S$ 0.02%)가 WGSR Process를 통해 98% CO가 $CO_2$ 로 전환되었다. Selexol 공정을 통해 $H_2S$ 제거율은 99.9%, $CO_2$제거율은 96.4%이었고 14.9kg/s의 $H_2$(86.9%) 연료를 얻었다. 모델링 결과는 신뢰성 검증을 통해 IGCC+CCS 전체 플랜트의 성능예측과 Feasibility Study를 위한 자료로 활용될 예정이다.