• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.137-139
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• 2003

Micro-Sources arc emerging as a providing environmentally friendly and reliable and effective solution. Micro-Source converter DC voltage of prime mover to AC voltage using voltage source inverter for interjecting with AC grid system. This paper studies optimal series inductance size for interjecting with AC grid system.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.25-26
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• 2009

아두이노 보드는 Atmel 8 비트 RISC 마이크로프로세서를 이용해서 제작된 임베디드 보드이다. 마이크로프로세서 내부에 프로그램을 쓸 수 있다는 기능과 하드웨어 설계도가 오픈소스로 제작된다는 점, 일반 사용자들을 위해서 제공되는 쉬운 개발 언어 및 개발 환경을 제공한다. 본 논문에서는 아두이노 보드 위에서 동작하는 임베디드 소프트웨어에 대해 테스트하는 방법과 앞으로의 테스트 방법에 대한 개발방향에 대하여 논한다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.42-48
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• 2009

Microgrid supplies loads with power interconnected grid. And it is defined a independent power system compounded micro sources over two devices which have enough capacity to operate independently, storage devices and loads. The energy sources of micro source have different dynamic characteristics corresponding to classes and application skills. However their transient responses are various from a few seconds to minutes. Therefore it is limitation for understanding operation characteristics of microsource modeling constant voltage source or constant current source. This paper shows that we designed EMTP/RV model of micro source which is microturbine based energy source. And we performed dynamic analysis of micro source corresponding to operation mode of microgrid.

• The Journal of Korean Association of Computer Education
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• v.10 no.4
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• pp.113-124
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• 2007

The virtual laboratory is implemented by Java applets and FLASH animations, which provides the learners with improved experimental methods. If the learners have access to the virtual laboratory system through signing up procedure, they can acquire the fundamental concepts and make a virtual experiment on 8051 microcontroller. In addition, we have implemented the remote laboratory for practicing 8051 microcontroller, which can be used to compensate the absence of reality, occurred during virtual laboratory session. Finally, the proposed integration laboratory provides the learners with almost all the same and advantages as a real laboratory environment.

• Journal of KIISE:Software and Applications
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• v.35 no.2
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• pp.59-69
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• 2008

Automatic obfuscation is known to be the most viable method for preventing reverse engineering intentional1y making code more difficult to understand for security purposes. In this paper, we study and implement an obfuscation method for protecting MS Visual C++ programs against attack on the intellectual property in software like reverse engineering attack. That is, the paper describes the implementation of a code obfuscator, a tool which converts a Visual C++ source program into an equivalent one that is much harder to understand. We have used ANTLR parser generator for handling Visual C++ sources, and implemented some obfuscating transformations such as 'Remove comments', 'Scramble identifiers', 'Split variables', 'Fold array', 'Insert class', 'Extend loop condition', 'Add redundant operands', and 'Insert dead code'. We have also evaluated the performance and effectiveness of the obfuscator in terms of potency, resilience, and cost. When the obfuscated source code has been compared with the original source code, it has enough effectiveness for software protection though it incurs some run-time overheads.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.167-167
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• 2013

최근 발수 특성은 자동차 표면, 건축 구조물, 가전제품 및 모바일 기기 등 여러 분야에서 사용되고 점차 그 필요성이 대두되고 있다. 이러한 발수성의 표면은 연 잎이나 곤충의 날개, 도마뱀의 발바닥 등 자연계의 여러 곳에서 관찰 할 수 있다. 특히 연 잎의 표면에서 나타나는 초발수 특성이 마이크로와 나노 크기의 돌기 구조와 표피 왁스 성분에 기인한다는 것이 밝혀지면서 이를 응용한 다양한 연구가 진행되고 있다. 본 연구에서는 물리적인 표면처리로 마이크로와 나노 구조물을 형성하고 그 위에 표면에너지를 낮출 수 있는 물질을 증착하여, 발수 특성을 가지는 표면을 개발하였다. 알루미늄 표면에 마이크로 크기의 알루미나(Al2O3) 분말을 이용한 블라스트(blast) 공정으로 마이크로 구조를 형성하고, 선형 이온 소스(LIS)를 이용한 Ar 이온 빔 에칭으로 나노 구조를 형성하였다. FE-SEM 분석을 통해 수~수십 마이크로 구조 위에 나노 크기의 구조가 형성 된 것을 관찰하였다. 마이크로와 나노 구조가 형성된 알루미늄의 표면에너지를 낮추기 위해 trimethylsilane (TMS) 및 Ar을 이용한 플라즈마처리로 표면에 기능성 코팅막을 형성하였다. 그 결과 TMS처리 전에 비해 표면에너지가 99.75 mJ/m2에서 9.05 mJ/m2으로 급격히 낮아지고 접촉각이 $54^{\circ}$에서 $123^{\circ}$로 향상되었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.2
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• pp.62-67
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• 2015

The carbon microspheres of a core-shell type were grown by the method of mixed-source hydride vapor phase epitaxy (HVPE). The surface and the cross section of the carbon microsphere grown by a new method were observed by scanning electron microscope (SEM). The characteristics of the carbon microsphere were investigated by X-ray photoelectron spectroscopy (XPS) and a high resolution-transmission electron microscope (HR-TEM). From these measurements, the diameters of carbon sphere were about few hundred micrometers. Furthermore, we show that the carbon microsphere of the core-shell type by mixed-source HVPE method can be grown successfully with the larger size than those of the existing one. This mixed-source HVPE method is proposed a new method for making of carbon microsphere.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.574-576
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• 2021

It is necessary to introduce micro-service techniques when constructing large-scale operating systems or systems that take into account scalability. Kafka is a message queue with the pub/sub model, which has features that are well applied to distributed environments and is also suitable for microservices in that it can utilize various data sources. In this paper, we propose a data sharing method for educational video sharing services using Apache's Kafka. The proposed system builds a Kafka cluster for the educational video sharing service to share various data, and also uses a spark cluster to link with recommendation systems based on similarities in educational videos. We also present a way to share various data sources, such as files, various DBMS, etc.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.59-65
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• 2019

The EMI shielding effectiveness of the shielding layer thickness was analyzed when the metal shielding layer was placed in the near field of the magnetic probe and the noise source. Microstrip lines were used as noise source, and graphite and ferrite were selected as metal shielding materials. The magnetic probe uses the electromagnetic radiation measurement method using the magnetic probe by applying the IEC 61967-6 method. The transmission coefficient between the microstrip line and the magnetic probe was analyzed. The distance between the two was 1 mm for a single shielding layer and 5 mm for a multiple shielding layer. The thickness of the shielding layer was changed to 5 um, 10 um, 30 um, and 50 um. When the frequency was changed from 150 kHz to 1 GHz, a maximum shielding effectiveness (SE) of 44.9 dB was obtained.

• The Korean Journal of Archival Studies
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• no.52
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• pp.119-170
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• 2017

This study aims to analyze the environment for the open-source records system and to identify the risk and requirements for the success of the strategy in Korea. For this, Chapter 2 presented a review of the strategic benefits of open source to public organizations, developers, and users. It also discussed the process of cooperatively developing and releasing the source code and the technology infrastructure supporting open source. In Chapter 3, six representative open-source projects in the field of records management were selected, and case studies were conducted. To derive comprehensive implications, we have divided the main development body of open-source projects into international organizations, international cooperation systems, national archives, and software development companies. We also analyzed the background and purpose of each project, the agents of development and funding, the governance model, the development period and cost, the business model and software architecture, the community composition, and the licensing strategy. Through this, we have derived four critical success factors. In terms of technology, a component-based design was required; therefore, we proposed a microservice architecture and a model-view-controller design pattern. Next, it was necessary to reestablish system requirements of records center and archives. Moreover, we also proposed a dual licensing strategy to allow developers to easily participate in open-source projects. Lastly, we emphasized a strong governance structure and an effective cooperation framework to create a sustainable community. For a record system to be open-source successfully in an organization-centered market, the roles of software developers and end users should be exercised more in the community. To achieve this, it is important to build various collaborative tools and development infrastructure from a planning stage to a centralized one.