• 한국안전학회지
• /
• 제17권3호
• /
• pp.112-117
• /
• 2002

무성 (유전체 장벽)방전기구의 질소산화물(NOx)제거효율에 대한 화학 반응역학의 전산모사 및 실험적 특성이 비교 조사되었다. 방전 전극구조에 따른 여러 종류의 유전체 장벽 방전기구가 구현되었으며 응용 방전환경 별 질소산화물(NOx)제거특성이 이론적, 실험적으로 고찰되었다. 전산모사 모델링은 유해 배가스에 대한 플라즈마 응용기구의 수학적 근접모델을 기초로 하였고 각 방전광(스트리머) 채널의 주 활성입자 생성에 의한 화학반응 종들의 비균일, 비평형 분포특성을 고려하였다. 모델링 전산모사로 얻어진 질소산화물(NOx) 제거효율은 관찰 실험특성과 오차 허용범위 내의 일치성을 나타내었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.218-221
• /
• 2006

This paper reports on a Realtime OS based motor control system for laparoscopic surgery robot which enables telesurgery and overcomes shortcomings with conventional laparoscopic surgery. The system has a conventional master-slave robot configuration and the control system consists of joint controllers, host controllers, and power units. The robot features (1) a compact slave robot with 5 DOF (Degree Of Freedom) expanding the workspace of each tool and increasing the number of tools operating simultaneously, and (2) direct 1:1 correspondence in the joint of master and slave robot that simplifies control algorithm and enhances reliability. Each master, slave and GUI (Graphical User Interface) host has a dedicated RTOS (RealTime OS), RTLinux-Pro (FSMLabs Inc., U.S.A.) Each master and slave controller set pair has a dedicated CAN (Controller Area Network) channel for control and monitoring signal communication. Total 4 pairs of the master/slave manipulators as current are monitored by one host controller for operation monitoring and higher level motion control. The system showed acceptable performance in both position control precision and master-slave motion synchronization and is now under further development for better safety and control fidelity for clinically applicable prototype.

• 한국항행학회논문지
• /
• 제13권1호
• /
• pp.27-33
• /
• 2009

채널 전송률이 40 Gbps인 WDM 채널들의 성능을 개선시키는 새로운 광전송 링크 기술을 제안하였다. 제안된 광전송 링크는 전체 전송로 중간에 광 위상 공액기 (optical phase conjugator)를 두고 전송로에서 축적된 분산은 분산 제어 (DM; dispersion management)을 통해 보상하는 구조이다. DM이 OPC와 결합하면 DM을 통해 전송 링크 전체에서 축적된 분산량을 줄여줌과 동시에 OPC에 의한 비선형성 보상의 정도를 더욱 좋게 하여 결과적으로 모든 채널들의 Q-factor가 크게 개선되는 것을 확인하였다. 그리고 모든 WDM 채널들의 Q-factor 개선은 광전송 링크의 전체 잉여 분산 (NRD; net residual dispersion)에 크게 의존한다는 것을 알 수 있었다.

• Journal of Communications and Networks
• /
• 제11권1호
• /
• pp.47-56
• /
• 2009

We investigate the connectivity of fading wireless ad-hoc networks with a pair of novel connectivity metrics. Our first metric looks at the problem of connectivity relying on the outage capacity of MIMO channels. Our second metric relies on a probabilistic treatment of the symbol error rates for such channels. We relate both capacity and symbol error rates to the characteristics of the underlying communication system such as antenna configuration, modulation, coding, and signal strength measured in terms of signal-to-interference-noise-ratio. For each metric of connectivity, we also provide a simplified treatment in the case of ergodic fading channels. In each case, we assume a pair of nodes are connected if their bi-directional measure of connectivity is better than a given threshold. Our analysis relies on the central limit theorem to approximate the distribution of the combined undesired signal affecting each link of an ad-hoc network as Gaussian. Supported by our simulation results, our analysis shows that (1) a measure of connectivity purely based on signal strength is not capable of accurately capturing the connectivity phenomenon, and (2) employing multiple antenna mobile nodes improves the connectivity of fading ad-hoc networks.

• 한국통신학회논문지
• /
• 제37B권9호
• /
• pp.767-777
• /
• 2012

Topology control increases channel efficiency by controlling transmission power of a node, and as a result, network lifetime and throughput are increased. However, reducing transmission range causes a network connectivity problem, especially in mobile networks. When a network loses connectivity, the network topology should be re-configured. However, topology re-configuration consumes lots of energy because every node need to collect neighbor information. As a result, network lifetime may decrease, even though topology control is being used to prolong the network lifetime. Therefore, network connectivity time needs to be increased to expend network lifetime in mobile networks. In this paper, we propose an Adaptive-Redundant Transmission Range (A-RTR) algorithm to address this need. A-RTR uses a redundant transmission range considering a node status and flexibly changes a node's transmission range after a topology control is performed.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
• /
• pp.1564-1567
• /
• 2005

Zinc oxide thin films were grown at the t emperature of $100^{\circ}C$ and $150^{\circ}C$ by means of plasma enhanced atomic layer deposition (PEALD) and conventional atomic layer deposition for applying to the transparent thin film transistor (TTFT). The growth rate of $1.9{\AA}/cycle$ with oxygen plasma is similar to that of film grown with water. While the sheet resistivity of ZnO grown with water is 1233 ohm/sq, that of film grown with oxygen plasma was too high to measure with 4 point probe and hall measurement system. The resistivity of the films grown with oxygen plasma estimated to be $10^6$ times larger than that of the films grown with water. The difference of electrical property between two films was caused by the O/Zn atomic ratio. We fabricated ZnO-TFT by means of ALD for the first time and the ZnO channel fabricated with water showed saturation mobility of $0.398cm^2/V{\cdot}s$ with bottom gate configuration.

• 설비공학논문집
• /
• 제18권6호
• /
• pp.459-467
• /
• 2006

Rapid development of electronic technology requires small size, high density packaging and high power in the electronic devices, which results in more heat generation. Suitable heat dissipation is required to ensure the guaranteed performance and reliable operation of the current state-of-the-art electronic equipment. The aim of the present study is to find out the forced-convective thermal-hydraulic characteristics of a pin-fin heat exchanger as a candidate for cooling system of the electronic devices through the analysis and experiment. Various configuration of the pin-fin array is selected in order to find out the effect of spacing and diameter of the pin-fin on the heat transfer and pressure drop characteristics. Experimental results are compared with the analyses and correlations of several researchers. Finally, the design guide are provided for the required pressure drop and/or the heat transfer characteristics of the heat exchanger.

• Nuclear Engineering and Technology
• /
• 제45권6호
• /
• pp.795-802
• /
• 2013

For the improvement of APR1400 Diverse Protection System (DPS) design, the Advanced DPS (ADPS) has recently been developed to enhance the fault tolerance capability of the system. Major fault masking features of the ADPS compared with the APR1400 DPS are the changes to the channel configuration and reactor trip actuation equipment. To minimize the fault occurrences within the ADPS, and to mitigate the consequences of common-cause failures (CCF) within the safety I&C systems, several fault avoidance design features have been applied in the ADPS. The fault avoidance design features include the changes to the system software classification, communication methods, equipment platform, MMI equipment, etc. In addition, the fault detection, location, containment, and recovery processes have been incorporated in the ADPS design. Therefore, it is expected that the ADPS can provide an enhanced fault tolerance capability against the possible faults within the system and its input/output equipment, and the CCF of safety systems.

• 한국강구조학회 논문집
• /
• 제14권1호
• /
• pp.31-40
• /
• 2002

적층된 박벽 복합재료 보의 자유 진동에 관한 연구를 수행하였다. 박벽 C형강 복합재료의 동적 거동에 적용 가능한 일반적인 해석 모델을 개발하였다. 이 모델은 classical lamination theory를 기초로 두고 있으며, 임의의 적층 상태의 구성 즉, 대칭뿐만 아니라 비대칭의 적층 상태, 그리고 다양한 경계조건에 따른 휨과 비틀림 형상의 연계(coupling)을 설명하였다. 변위를 기반으로 한 일차원 유한 요소 모델은 박벽 복합재료 보의 고유 진동수와 그에 대응하는 진동 모드를 예측하기 위해 개발되었다. 운동방정식은 Hamiton의 원리로부터 유도되었으며, 수치적인 결과는 박벽 복합재 보에서 복합재료의 진동수와 모드 형상에 대해 적층각, 계수비, 그리고 경계조건의 영향을 얻을 수 있었다.

• 천문학논총
• /
• 제19권1호
• /
• pp.101-107
• /
• 2004

This paper describes the digital back-end system for getting the data to analyze the user observation mode by digitalize the analog data after receiving the space radio using the radio telescope, The received analog data will be digitalized by high-speed sampler with 1 Gsps for 4 channel frequency band of millimeter wave, and the digital data will be transported through the fiber-optic digital transmission system and WDM(wavelength division multiplex) to observation building, The wideband digital FIR(Finite Impulse Response) filters analyze the data for user observation mode to record the data in high-speed recorder with 1 Gbps. In this paper, we introduce the overall system configuration and features combined by various information and communication technology in radio astronomy briefly, which will be adopted by KVN(Korean VLBI Network).