• 한국산학기술학회논문지
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• 제20권12호
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• pp.804-815
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• 2019

화석연료의 고갈 및 지구 온난화 등 환경문제에 대응하기 위해 세계는 화석연료를 대신할 에너지에 대한 연구를 진행하였고, 그중 바이오매스가 대체에너지로써 주목받고 있다. 바이오매스는 재생 가능하고 탄소 중립(carbon neutral)적인 특성이 있으나 수분함량이 많고 낮은 에너지밀도를 가지므로 에너지 생산 시스템에 이용하기 위해서는 열화학적 변환 공정이 필요하다. 그중 하나인 가스화는 바이오매스로부터 수소, 일산화탄소, 메탄 등으로 구성된 합성가스(syngas)를 생성시켜 연료로써 이용할 수 있도록 해준다. 그러나 가스화 과정 중에 발생되는 타르와 입자상 물질은 배관, 연소 엔진, 발전 터빈 등에서 막힘 현상을 일으켜 공정 효율을 감소시키는 문제를 야기하므로 제거가 필요하다. 본 연구에서는 가스화 공정에서 발생되는 타르를 비롯한 입자물질에 대해 제거 효율이 뛰어난 필터를 사용하였으며, 타르로부터 필터 눈 막힘 현상을 방지하기 위해 pre-coating 기술을 적용하였다. pre-coating에 사용된 물질로써는 소석회와 활성탄(wood char)을 사용하였으며, 타르 및 입자에 대한 제거효율이 소석회 코팅의 경우 86 %, 활성탄(wood char)의 경우 80 %로 나타났다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.176-177
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• 2016

In the last few decades, attention toward atmospheric pressure plasma (APP) has been greatly increased due to the numerous advantages of those applications, such as non-necessity of high vacuum facility, easy setup and operation, and low temperature operation. The practical applications of APP can be found in a wide spectrum of fields from the functionalization of material surfaces to sterilization of medical devices. In the secondary battery industry, separator film has been typically treated by APP to enhance adhesion strength between adjacent films. In this process, the plasma is required to have high stability and uniformity for better performance of the battery. Dielectric barrier discharge (DBD) was usually adopted to limit overcurrent in the plasma, and we developed the pre-discharge technology to overcome the drawbacks of streamer discharge in the conventional DBD source which makes it possible to produce a super-stable plasma at atmospheric pressure. Simulations for the fluid flow and electric field were parametrically performed to find the optimized design for the linear jet plasma source. The developed plasma source (Plasmapp LJPS-200) exhibits spatial non-uniformity of less than 3%, and the adhesion strength between the separator and electrode films was observed to increase 17% by the plasma treatment.

• 정보처리학회논문지A
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• 제9A권1호
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• pp.129-136
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• 2002

JNI는 자바가 플랫폼 의존적인 특수한 기능을 이용할 수 있게 하고, 기존의 라이브러리와 프로그램을 재사용할 수 있게 하기 위해 C/C++와 같은 다른 프로그래밍 언어와 연결되는 방법이다. 그러나 JNI를 사용하기 위해서는 복잡하고 어려운 과정을 거쳐야 하며 자바 소스와 C/C++ 소스를 따로 다루어 불편하였다. 본 논문에서는 JNI를 쉽게 사용하기 위해서 동일한 파일에 자바 소스와 C/C++ 소스를 함께 작성할 수 있게 하고 JNI 사용에 필요한 단계들을 줄인 JPP(Java PreProcessor)를 설계하고 구현하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.229-234
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• 2008

Korea Electric Power Corporation (KEPCO) has started the nation's first biogas-microturbine project in the city of Gongju as an effort to encourage the utilization of wasted biogas containing useful energy source in the form of $CH_4$. The goal of the project is to set up the biogas microturbine co-generation system for utilizing biogas as an energy source and improving the economics of the wastewater treatment plant. Wastewater treatment processes were investigated in depth to find improvement possibility. Changes in internal recirculation ratio and pre-treatment degree are needed to optimize plant operation and biogas production. Biogas pre-treatment system satisfies Capstone's fuel condition requirement with the test result of 99.9% and 90.2% of hydrogen sulphide and ammonia is removal performance. Installation of microturbine and manufacture of heat exchanger to warm anaerobic digester has been done successfully. Expected economic profit produced by the system is coming from energy saving including electricity 115,871kWh/year and heat contained in exhaust gas 579GJ/year.

• 산업기술연구
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• 제16권
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• pp.13-24
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• 1996

This research aims to investigate the effects of an internal carbon source in the denitrification of piggery wastewater. In this study, the raw wastewater and the effluent from each of anoxic basin and anaerobic basin were used as the internal carbon sources. The experiments were carried out in batch system and the results are as follows ; i) Denitrification rates were the highest in the raw wastewater and the lowest in the anaerobic effluent. ii) The piggery wastewater contained about 60 percent of the readily biodegradable organic(RDCOD), which led to a conclusion that the raw wastewater could be used as the internal carbon source for the denitrification. For the efficient denitrification, pre-denitrification process was found profitable. iii) In denitrification, alkalinity production rates were in the range of 3.4 to $3.6mgCaCO_3/mgNO_3-N$. iv) The denitritation of piggery wastewater came out to be possible, and the rate of organic carbon consumption decreased about 10 percent.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2017년도 춘계 종합학술대회 논문집
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• pp.405-406
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• 2017

With the advance of ICT technology, E-Commerce is getting popular and used widely in daily life. Nowaday's commercial videos are also being used extensively to introduce commercial products to consumers. Most commercial companies are advertising their products on the internet with images and videos through online sharing sites. Putting pre-recorded videos online is easy, but it is difficult for sellers to interact with customers. Live Streaming is the transmission of digital content directly to the Internet in real time. Although there are many services available that provide live streaming on the internet, most are limited in the content they transmit. Building live streaming servers using open source projects will help users master the content which conveys to their customers. In this paper, we will consider implementation of Live Streaming Server for Video Commerce using Open Source.

• 대한산업공학회지
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• 제22권3호
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• pp.387-398
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• 1996

In this study the cell arrival processes from pre-buffer into multiplexer for MPEG(Motion Picture Experts Group) coding video sources are analyzed with consideration of the traffic periodicity in frame level. The analysis is performed by introducing the two arrival models, that is, periodic on/off source model and periodic uniform arrival model. Modulated $N^*D$/D/1 queueing system is utilized in periodic on/off source model, while ${\Sigma}{N_i}^*D_i$/D/1 queueing system is used in periodic uniform arrival model. The presented models are validated by comparing with computer simulations. Numerical results for periodic uniform arrival model are shown to be very accurate, but those of periodic on/off source model are shown to be inaccurate as the number of sources are increased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.211-213
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• 1999

This paper describes a new method for source current optimization of the electromagnetic devices. In a conventional method of current distribution optimization using design sensitivity based on a finite element method, position and width of coils are generally optimized under condition that shape of those is given. they cannot find the global minimum because the number of coils is pre-determined. To avoid this local minimum, source current region which is discretized uniformly is considered as design parameter. This discretized regions have zero or one current value during the optimization process. The proposed method is applied to magnetic resonance imaging(MRI) magnet.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.967-976
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• 2021

This study aimed to investigate the mechanism by which service companies transfer their services overseas and create new value while interacting with local characteristics. A narrative analysis method was used in a case study of Ajisen Ramen, a Japanese service company that created a Japanese-style ramen restaurant, which experienced rapid growth in China. This study analyzed the restaurant as global service innovation and constructed a causal mechanism to explain the resulting rapid growth. In the pre-entry stage, the tangible value source core service facilitated its successful overseas transfer. In the post-entry stage, value source core service standardization and value sharing were interrelated and locally accepted factors. Knowledge of the local characteristics influenced the local storefront format that allowed contact with local customers. This local front format made it possible to offer local customers new value. The global service innovation mechanism developed through this study reflects a causal diagram that correlated the theoretical concepts of these events.

• 한국정보과학회논문지:정보통신
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• 제34권2호
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• pp.120-133
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• 2007

전송-수신 쌍들을 연결하는 많은 수의 경로들로 이루어진 멀티캐스트 트리에서 네트워크 구성요소의 실패는 멀티캐스트 트리의 일부를 손상시킬 수 있다. 그러나 하나의 구성요소의 실패를 복구하기 위해 전체 멀티캐스트 트리를 다시 만드는 것은, 실패의 영향을 받지 않은 경로를 사용하는 그룹 멤버들까지도 서비스의 중단을 겪어야 하기 때문에 바람직하지 않다. 본 논문은 QoS 멀티캐스트 트리에서 재구성해야 할 영역을 줄이면서 재구성의 성공 가능성을 최대화하는 계획된 재구성(Pre-Planned Reconfiguration: PPR) 정책을 제안한다. PPR 방식은 멀티캐스트 트리의 전송-수신 쌍을 연결하는 각 경로에 재구성 경로를 미리 만들고, 이들 경로에 필요한 자원을 미리 예약해 둔다. 이를 위해 우리는 기존 멀티캐스트 트리의 변화를 최소화하며 손상되지 않은 부분들의 서비스를 최대한 유지하는 재구성 경로의 라우팅 방법을 고안하였으며, 효율적 자원 공유 방법을 사용하여 재구성 경로들을 위해 예약된(실패가 일어나지 않을 경우 사용되지 않는) 자원의 양을 줄인다. PPR 방식은 실패 복구를 위해 여러 멀티캐스트 세션들이 동시에 엄청난 경쟁을 하는 것을 막을 수 있다. 시물레이션을 통해 최단경로 라우팅을 사용하는 전송자 중심 멀티캐스트 트리와 공유 멀티 캐스트 트리에서 각각 성능을 평가한 결과 PPR 방식은 적당한 오버헤드내에서 모든 그룹 멤버들에게 성공적인 재구성을 제공한다. 또한 PPR 방식은 그룹 멤버쉽이 동적으로 변화할 때에도 잘 적응한다.