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서버를 통한 Bluetooth 기기 자동 연결 및 데이터 직접 송수신 기법 연구
박재만 ( Jaeman Park ) 한국정보처리학회 2012 한국정보처리학회 학술대회논문집 Vol.19 No.2
블루투스(Bluetooth)는 일반적으로 10m 안팍의 휴대폰, 노트북 등의 휴대기기를 서로 연결해 정보를 교환하는 근거리 무선 기술 표준이다. 이 표준 기술은 이어폰이나 기기간의 페어링을 통하여 정보를 공유하기위한 단일 서비스 제품으로 자주 사용되기도 하며, 스마프폰에서는 이 표준 기술을 제어하여 명함이나 개인의 사진, 동영상 그리고 문서파일등을 공유하기 위한 방식으로 활용되기도한다. 하지만 가장 큰 문제는 Bluetooth 를 응용하여 기기간의 페어링을 진행하는 절차가 일반적 사용자에게는 너무 복잡하고, 기술적인 처리 방식을 요구함으로써 대중화된 서비스를 지원하기에는 부족한 점이 많다. 따라서, 본 논문에서는 Bluetooth 환경하에서 사용자에게 직접적인 파일 전송을 지원하기 위해 서비스 서버에서 각 단말의 정보를 통합 수신하고, 이를 각 단말에 전달하여 각 단말이 자동적으로 Bluetooth 연결을 구성하고 서비스는 이를 활용하여 Direct 하게 파일을 송수신하는 간결화된 근거리 기반의 통신 연결 서비스 구성 방식을 제안하고 이를 증명하고자 한다.
Analysis of Degradation of Durability of the GDL with Various MPL Penetration Levels
박재만(Park, Jaeman),조준현(Cho, Junhyun),하태훈(Ha, Taehun),민경덕(Min, Kyoungdoug),이은숙(Lee, Eunsook),정지영(Jyoung, Jy-Young) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.11
Durability problems of gas diffusion layer(GDL) is one of the important issues for accomplishing commercialization of proton exchange membrane fuel cell(PEMFC). GDL is strongly related to the performance of PEMFC because one of the main function of GDL is to work as a path of fuel, air and water. When the GDL is degraded, it causes water balance problems such as the flooding phenomenon. Thus, investigating the durability characteristics of the GDL is important and understanding the GDL degradation process is needed. In this study, the GDLs are degraded by carbon corrosion stress method which is the electrochemical degradation mode. To determine the effects of carbon corrosion of the GDL, 1.45 V of potential is imposed for 96 hours. In this manner, in the previous research, the structure between the substrate and the MPL is weaken. Further investigations are needed to clarify this phenomenon. Therefore, in this study, the carbon corrosion stress method is carried out with GDLs which have various MPL penetration levels and the effects of the MPL penetration level on the characteristics change of the GDL are analyzed. The changes in characteristics are measured with various properties of GDL such as weight, thickness and static contact angle. The degraded GDL shows loss of their properties.
고분자 전해질형 연료전지의 기체 침식에 의한 가스확산층 내구성능 저하에 관한 실험적 연구
박재만(Jaeman Park),하태훈(Taehun Ha),조준현(Junhyun Cho),민경덕(Kyoungdoug Min),이은숙(Eunsuk Lee),정지영(Jiyoung Jung),김도훈(Dohun Kim),진용원(Yongwon Jin) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
Durability characteristics of Gas Diffusion Layer (GDL) is one of the issues for maintaining the Polymer Electrolyte Membrane Fuel Cell (PEMFC) performance because one of the main function of GDL is to work as a path of fuel and water. When GDL degradation occurs, the main function of GDL is lowered and it causes the flooding phenomenon. Therefore, to investigate the durability of GDL, understanding the GDL degradation process is required. However, the GDL degradation has complex process and is caused by various reasons. Therefore, separating each reasons and investigating its effect are needed. In this study, mechanical degradation with gas flow test, which is one of the GDL degradation mechanisms, is introduced. To consider the effect by gas flow, gas is only fed into the unit cell continuously. And other conditions for unit cell is set up to the PEMFC for automotive applications. The amount of GDL degradation was measured with various measurement methods such as weight measurement and static contact angle measurement. After 2,400 hours test, the degradated GDL Showed loss of weight and contact angle.
박재만(Park, Jaeman),민경덕(Min, Kyoungdoug),강상규(Kang, Sanggyu) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11
High temperature proton exchange membrane fuel cell (HT-PEMFC) has been regarded as a promising clean energy sources. In this study, a quasi-three-dimensional dynamic model of HT-PEMFC has been developed and the local dynamic characteristics are investigated. The model has the geometrical simplification of 2+1D reduction (quasi-3D). The one-dimensional model consists of nine control volumes in cross-sectional direction to solve the energy conservation and the species conservation equations. Then, the one-dimensional model is discretized into 25 local sections along the gas flow direction to account for gas and thermal transport in channels. With this discretization, the local characteristics of HT-PEMFC such as species conservation, temperature, and current density can be captured. In order to study the basic characteristics of HT-PEMFC, it is important to investigate the local dynamic characteristics. Thus, the model is simulated at various operating conditions and the local dynamic characteristics related to them are observed. The model is useful to investigate the distribution of HT-PEMFC characteristics and the physical phenomena in HT-PEMFC.