• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.210-211
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• 2002

산업의 발전과 급속한 대도시화는 환경오염이라는 새로운 사회적 이슈를 발생시켰다. 시정(Visual Range)이란 대기의 혼탁도를 나타내는 기상요소로서, 정상적인 시각을 가진 사람이 목표를 식별할 수 있는 최대거리를 의미한다 시정은 대기오염을 판단할 수 있는 척도이며, 항만 및 공항 등에서는 인명 및 재산과 직접적인 관계를 갖고 있어, 최근 시정 측정에 대한 중요성이 높아지고 있다. 본 논문에서는 배경 잡음에 좋은 특성을 가지며, 보디- 정확한 시정 측정을 위하여 905nm 펄스 모드 반도체 레이저 다이오드를 이용한 시정계 센서를 제작하여 실험하였다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.65-66
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• 2007

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.698-700
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• 2000

원활한 RTS 게임의 진행을 위해서 경로 찾기의 역할은 절대적이다. 경로 찾기는 게임 유닛의 진행이나 행동에 따라 무한 발생하며 게임의 특성에 따라 변하기 쉽기 때문에 유연해야 한다. 이는 게임의 자유도를 높이는데 중요한 요소가 된다. 그러나 경로 찾기는 맵의 속성이나 환경 또는 사용자의요구에 따라 행동 패턴들이 무한 발생하므로 체계적 알고리즘을 만들기가 어려워 많은 문제를 일으킨다. 기존의 게임에서는 알고리즘이 맵 상의 협곡에서 속성 처리를 제대로 하지 못하였다. 본 논문에서는 대기모드의 추가를 통한 해결에 방안을 제시 한다.

• Journal of IKEEE
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• v.15 no.2
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• pp.134-142
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• 2011

This paper describes a tripple-mode high-efficiency DC-DC buck converter. The DC-DC buck converter operate in PWM(Pulse Width Modulation) mode at moderate to heavy loads(100mA~500mA), in PFM(Pulse Frequency Modulation)at light loads(1mA~100mA), and in LDO(Low Drop Out) mode at the sleep mode(<1mA). In PFM mode DPSS(Dynamic Partial Shutdown Strategy) is also employed to increase the efficiency at light loads. The triple-mode converter can thus achieve high efficiencies over wide load current range. The proposed DC-DC converter is designed in a CMOS 0.18um technology. It has a maximum power efficiency of 96.4% and maximum output current of 500mA. The input and output voltages are 3.3V and 2.5V, respectively. The chip size is 1.15mm ${\times}$ 1.10mm including pads.

• The KIPS Transactions:PartA
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• v.15A no.2
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• pp.69-74
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• 2008

This paper proposes a structure of low-power MOS current-mode logic circuit with sleep-transistor to reduce the leakage current. The sleep-transistor is used to high-threshold voltage transistor to minimize the leakage current. The $16\;{\times}\;16$ bit parallel multiplier is designed by the proposed circuit structure. Comparing with the conventional MOS current-model logic circuit, the circuit achieves the reduction of the power consumption in sleep mode by 1/50. This circuit is designed with Samsung $0.35\;{\mu}m$ CMOS process. The validity and effectiveness are verified through the HSPICE simulation.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.22-31
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• 2013

Flight tests on flight control performance of helicopter, conversion and airplane mode for the Smart UAV were completed. Automatic take-off and landing, automatic return home as well as automatic approach to hover were performed in helicopter mode. Climb/descent, left/right turn using speed and altitude hold mode were performed in each $10^{\circ}$ tilt angle in conversion mode. The rotor speed in airplane mode was reduced to 82% from 98% RPM in order to increase rotor efficiency with reducing Mach number at tip of rotors. It reached to the designed maximum speed, $V_{TAS}$=440 km/h at 3 km altitude. This paper presents the flight test result on full envelopment of Smart UAV. Detailed test plan and test data on control performance were also presented to prove that all data meets the flying qualities requirement.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.349-355
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• 2017

Failures of railway systems can result in train delays or accidents, and therefore high reliability is required to ensure safety of railway systems. To improve reliability, railway systems are designed with redundant systems so that the standby system will continue to function normally even if the primary system fails. Generally, overall system reliability can be evaluated by the reliabilities of the parts of the whole system and the reliability of the redundant system considering common failures in case of each system is not conform physical, functional and process independent. In this study, the reliability of the hot-standby sparing system is analyzed the independent systems and dependent systems with common failures. The reliability for the standby system can be effectively analysed using Markov models, which can model the redundant configuration and the state transition.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.466-475
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• 1992

ISDN으로 통합되고 있는 중요한 서비스 중의 하나가 데이터의 효율적인 전달을 위한 패킷모드 서비스이다. 이 패킷모드 서비스는 융통성이 있는 대역폭할당이 가능하고 하나의 물리적 채널을 동시에 복수개의 논리적 채널로 사용할 수 있다. CCITT권고안 X.31은 현존하고 있는 X.25패킷 터미날을 ISDN으로의 액세스를 지원하기 위한 두 가지의 시나리오를 설명하고 있다. ISDN교환기로서 개발되고 있는 TDX-10 전자교환기는 패킷처리기(Packet Handler)가 ISDN내에서 패킷모드 서비스를 제공하는 X.31의 Case B를 채택하고 있다. 본 논문에서는 모든 패킷 트래픽이 집중되어 처리되는 패킷처리기 역할을 하는 패킷처리 서브시스템(Packet Handling Subsystem)의 구조를 간략하게 설명하였다. 또한 TDX-10 패킷처리기의 성능을 제시하기 위하여 패킷처리기를 큐잉 네트워크를 이용하여 모델링하고, SLAM II를 사용하여 시뮬레이션을 수행하였다. 그 결과 부가된 트래픽 변화에 따른 각 프로세서의 CPU점유율 및 입력큐에서의 평균 대기시간, X.25호 요구 지연시간과 데이터 패킷 전송 지연시간등을 분석하고 이를 근거로 TDX-10 패킷교환시스팀의 패킷호 처리용량을 제시하였다.

• Journal of Korea Soil Environment Society
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• v.3 no.2
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• pp.79-88
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• 1998

The purpose of this study was to estimate the removal potential of landfill gases during landfill mining project. Air injection mode and landfill gas extraction mode were tested. A mode that air injected at one injection well and landfill gas extracted at another extraction well at the same time was also tested to compare. The flow rates of all modes were the same as 15$\textrm{km}^2$/min. Air injection mode was the most effective in removing $CH_4$. Air injection/extraction mode didn't improve the effectiveness of removing CH$_4$compared with air injection mode. Air injection mode were more advantageous than air injection/extraction mode in respect to energy consumption because that of air injection/extraction mode were doubled.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.3
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• pp.1-11
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• 2018

This paper explores the reliability issue especially associated with the time-division synchronous communication when a networking stack is implemented using software timers provided by embedded operating systems. Especially, we explore the reliability of beacon synchronization of IEEE 802.15.4. Our experiments based on its practical implementation clearly show that processing delays or losses of hardware timer interrupts used for software timers lead to occasional failures in beacon synchronization. To avoid such failures, we suggest a reception time compensation scheme that turns on the receiver earlier than expected.