• 정보보호학회논문지
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• 제16권6호
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• pp.25-35
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• 2006

무선 주파수 인식 (RFID: Radio Frequency Identification) 시스템은 원거리 사물 인식 시스템의 중요한 기술로 인식되고 있다. 그러나 RFID 태그의 사용은 시스템 보안과 프라이버시 침해의 문제를 발생시킨다. 저가형의 RFID 시스템은 연산 능력, 전원 공급, 데이터 저장량 등에서 제약을 받는다. 그러므로 RFID 시스템에서의 태그의 연산량은 저가형의 RFID 시스템 환경에서 중요한 요소로 고려되어야만 한다. 본 논문에서는 태그가 단 한 번의 해쉬 연산만으로 상호 인증을 수행하는 효율적인 인증 프로토콜을 제안하며, 제안된 기법은 분산시스템에 적용 가능하기 때문에 유비쿼터스 환경에 적용 가능하다.

• 재무관리논총
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• 제6권1호
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• pp.313-334
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• 2000

In this paper, we obtained some supportive evidence for the long-run PPP relationship concerning the Korean Won currency. Previous tests of PPP in the bilateral exchange rates of the Korean Won rate vis-a-vis the U.S. Dollar have been exposed to the lack of power problem. We argue that their failure to find PPP relation in Korean Won rates was due to the low power of Augmented Dickey-Fuller tests or the Engle-Granger two-step tests applied to the Korean exchange rate data with short sample period. En attempting to alleviate this low power problem, we used the error-correction model test and the Johansen test for bilateral long-run equilibrium relationships between exchange rates and price indices from Korea's major trading partners. It is surprising that our evidence supporting for long-run PPP in Korean Won rate contrasts sharply with Bahmani-Oskooee, Moshen and Rhee, Hyun-Jae(1992)'s.

• 한국멀티미디어학회논문지
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• 제17권5호
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• pp.573-581
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• 2014

The salient features of UWB(Ultra WideBand) networks such as high-rate communications, low interference with other radio systems, and low power consumption bring many benefits to users, thus enabling several new applications such as wireless universal serial bus (WUSB) for connecting personal computers (PCs) to their peripherals and the consumer-electronics (CE) in people's living rooms. Because the size of multimedia data frame, WiMedia device must transmit the fragment of MSDU. However, when the fragment of MSDU is lost, WiMedia device maintains active mode for the time to complete the transmission MSDU, and there is a problem that unnecessary power consumption occurs. Therefore we propose new power management scheme to reduce unnecessary power consumption of WiMedia devices in the case that the fragment is lost.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.196-198
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• 2003

The low load power factor causes various problems such as the increase of the power loss and the voltage instability. The demand of reactive power increases continuously with the growth of active power and the restructuring of electric power companies makes the integrated management of ractive power troublesome, from which the systematic control of load power factor is required. In this paper, the load power factor sensitivity of the generation cost is derived and its effects in supplying the reactive power and enhancing the load power factor are analyzed in a small-scale power system. The load power factor sensitivity of the generation cost is applied for determining the locations and capacities of reactive power compensation devices. It is shown that the generation cost can be reduced and the system power factor can be enhanced effectively using the load power factor sensitivity.

• 한국멀티미디어학회지
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• 제7권4호
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• pp.30-39
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• 2003

• 전기전자학회논문지
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• 제20권3호
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• pp.318-321
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• 2016

IoT 산업이 빠르게 성장하면서 전원 관리 집적회로의 중요성이 부각되고 있다. 본 논문에서는 리플 Subtractor, 피드 포워드 커패시터, OTA를 이용한 LDO 구조를 제안한다. 이를 통해 10MHz가 넘는 고주파 영역에서도 -40dB 이상 높은 전원 전압 제거비(PSRR)를 얻었다. 설계된 Low-Dropout(LDO) 레귤레이터는 $0.18{\mu}m$ CMOS 공정에서 설계되었으며 시뮬레이션 결과 PSRR은 부하 전류 40mA, 500kHz에서 -73.4dB다. 최대 구동 가능 전류는 40mA이다.

• Journal of Electrical Engineering and Technology
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• 제11권2호
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• pp.353-360
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• 2016

Series hybrid electric vehicles (SHEVs) having multiple power sources such as an engine- generator (EnGen), a battery, and an ultra-capacitor require a power control unit with high power density and reliable control operation. However, manufacturing using separate individual power converters has the disadvantage of low power density and requires a large number of power and signal cable wires. It is also difficult to implement the optimal power distribution and fault management algorithm because of the communication delay between the units. In order to address these concerns, this approach presents a design methodology and a power control algorithm of an integrated power converter for the SHEVs powered by multiple power sources. In this work, the design methodology of the integrated power control unit (IPCU) is firstly elaborately described, and then efficient and reliable power distribution algorithms are proposed. The design works are verified with product-level and vehicle-level performance experiments on a 10-ton SHEV.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.153-155
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• 2004

Various problems such as the increase of the power loss and the voltage instability may often occur in the case of low load power factor. The demand of reactive power increases continuously with the growth of active power and the restructuring of electric power companies makes the integrated management of ractive power a troublesome problem, so that the systematic control of load power factor is required. In this paper, the load power factor sensitivity of the generation cost is used for determining the locations of reactive power compensation devices effectively and for enhancing the load power factor appropriately. In addition, the integrated costs are used for determining the value of the load power factor from the point of view of the economic operation. It is shown through the application to a large-scale power system that the system power factor can be enhanced effectively and appropriately using the load power factor sensitivity and integrated costs.

• 대한안전경영과학회지
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• 제21권2호
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• pp.1-8
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• 2019

Most of gas turbine combined cycle power plants are located in urban areas to provide peak load and district heating. However, NOx(nitrogen oxides) of exhaust gas emission from the power plants cause additional fine dust and thus it has negative impact on the urban environment. Although DLN(dry low NOx) and multi-stage combustors have been widely applied to solve this problem, they have another critical problem of damages to combustors and turbine components due to combustion dynamic pressure. In this study, the effect of different fuel ratio on NOx emission and pressure fluctuation was investigated regarding two variable conditions; combustor stages and power output on M501J gas turbine.

• 대한안전경영과학회지
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• 제24권2호
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• pp.1-9
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• 2022

In korea, 500MW standard coal fired power plants were designed and operated for the initial base load, so facility stability was prioritized from facility problem to treatment, but now we needed to research for minimizing greehouse gas emissions at the operation of coal fired power plants. research on various facilities and technologies was actively conducted to reduce environment pollutants was drastically reduced, but research and attempts on coping measures in the event of a reduction facility problem were in sufficient. this study considered investigated ways to minimized pollutants by quickly responding to logic development and application of the load runback concept in case of serious problems with environmental pollutant reduction facilities such as NOx reduction selective catalytic reduction facilities, SOx reduction wet flue gas desulpherisation facilities, and TSP(Total Suspended Particles) collection low temperature electric precipitator.