• 한국산업융합학회 논문집
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• 제25권2_2호
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• pp.279-287
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• 2022

Butterfly valves installed on ships use valves with up to triple offset to improve tightness. However, the triple offset valve has structural problems such as disc deformation and seat separation. Accordingly, interest in quadruple offset butterfly valves with added offset is increasing. In this study, the structural safety of the quadruple offset butterfly valve was examined through numerical analysis. In addition, we intend to evaluate the performance of the valve through flow coefficient analysis.

• 대한조선학회 특별논문집
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• 대한조선학회 2008년도 특별논문집
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• pp.1-9
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• 2008

This report contains the results of structural analysis for the verification of the optimum offset range on the top of T-Bar with stiffener and BKT using at DSME Offset range as $6.0{\sim}10.0mm$ based on the 3-D FE analysis and experimental results of angie type stiffener as described in Annex 1 has been used as yard standard over ten (10) years under all Classification approval. Recently, Owner and Class have requested the confirmation for the misalignment based on the Yard's Standard so that a couple of locations for LNGC and LPGC has been investigated the structural strength by FE method using the offset ranges from 0.0 to 18.0 mm.

• 한국전자파학회논문지
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• 제22권2호
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• pp.258-264
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• 2011

본 논문은 GSM(Global System for Mobile communications)에서 주로 사용되는 Offset-PLL(Phase Locked Loop) 방식을 사용하여 낮은 위상 잡음과 빠른 위상 고정 시간, 우수한 불요파 특성을 갖는 주파수 합성기를 설계 제작하였다. 제안된 주파수 합성기의 구조는 3번의 주파수 하향 변환을 통해 낮은 위상 잡음 갖도록 하였으며, 높은 주파수 해상도를 갖도록 세 개의 offset 주파수중 최종 offset 주파수를 DDS(Direct Digital Synthesizer)를 이용하여 생성하였다. 또한, 빠른 스위칭 속도를 가질 수 있도록 DAC(Digital to Analog Converter)를 사용하였다. DAC 사용에 따른 위상 잡음 열화를 줄이기 위해 DAC 노이즈 제거를 위한 필터를 설계하여 성능을 개선하였다.

• 한국기후변화학회지
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• 제7권3호
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• pp.283-288
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• 2016

In this study, applicability of GHG ETS Offset Program in Korea for a refrigerant sector was analyzed by reviewing foreign management policy and project status in progress related to refrigerants in the disposal stage. In order to derive the implication of the domestic Offset Program, it was looked into approved offset projects and certified offset credits current state in Korea. Offset Program has approved 22 methodologies up to the present, so it is necessary to enhance the accessibility to GHG reduction in various industrial sector including the refrigerant sector by developing appropriate methodologies. In this study firstly, it was investigated that management regulation of countries are managing the refrigerants in the disposal stage such as United States, Japan, Australia. Secondly, of CDM methodologies there were two methodologies associated with the refrigerant reduction(treatment), which were decomposition HFC-23 and destruction of HFC-134a. Also there were a non-registered methodology about destruction of HFC-134a of end of life vehicles. Lastly, in California according to Compliance Offset Program, there was Compliance Offset Protocol in ODS Projects that provided eligible conditions. Based on the review, it was examined the possible conditions for domestic offset project for refrigerant sector

• 한국기후변화학회지
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• 제7권2호
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• pp.137-142
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• 2016

To achieve large-scale carbon removals, a carbon offset project based on forest management was designed and its carbon stock change was estimated in this study. The project was designed for 874 hectares of forests in the Jin-An Leading Forest Management Zone. For estimating the carbon stock change of the project, the Korean Forest Carbon Standard and VCS (Verified Carbon Standard) methodologies were applied. Three types of management options were considered in the project : extension of rotation age, conversion to productive forests, and conversion to selective harvesting. The estimated carbon removals from the project designed in this study were $259,936tCO_2$ ($8,664tCO_2$ annually), which is 98% of estimated carbon removals from the entire 69 projects currently registered to the Forest Carbon Offset Registry in Korea. The results of this study showed that a large-scale carbon offset project based on forest management could have a huge potential to produce carbon offset credits.

• JSTS:Journal of Semiconductor Technology and Science
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• 제8권4호
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• pp.318-325
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• 2008

A 1.2 V 7-bit 1 GS/s CMOS flash ADC with an interpolation factor of 4 is implemented by using a $0.13\;{\mu}m$ CMOS process. A digital calibration of DC reference voltage is proposed for the $1^{st}$ preamp array to compensate for the input offset voltage of differrential amplifiers without disturbing the high-speed signal path. A 3-stage cascaded voting process is used in the digital encoder block to eliminate the conescutive bubbles up to seven completely, if the $2^{nd}$ preamp output is assumed to have a single bubble at most. ENOB and the power consumption were measured to be 5.88 bits and 212 mW with a 195 MHz $400\;mV_{p-p}$ sine wave input.

• 자원ㆍ환경경제연구
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• 제24권3호
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• pp.463-488
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• 2015

본 연구에서는 2015년부터 시행된 온실가스 배출권 거래제도에 맞추어 상쇄(offset)제도의 구체적인 설계가 필요한 시점에서, 가정부문의 고효율 전자기기의 보급을 통해 확보할 수 있는 잠재 상쇄 공급량을 추정하였다. 분석대상 품목은 TV, 세탁기, 선풍기, 냉장고, 에어컨 등 다섯 가지 가전기기이며, 자기회귀시차분포모형(ARDL)을 통해 2016년부터 2022년까지의 고효율 가전기기의 보급대수를 추정하고, 효율 개선을 통한 전기 절감량과 이에 따른 탄소 환산율을 통해 최종적으로 잠재 상쇄 공급량을 도출하였다. 고효율 가전기기의 에너지 절감률을 각각 10%와 20%로 가정했을 때 2022년에 누적된 탄소 저감량은 $361,899CO_2t$과 $723,797CO_2t$으로 나타났으며, 에너지 절감량이 큰 순서로는 에어컨, 냉장고, TV, 세탁기, 선풍기 순으로 나타났다. 또한 에너지 소비효율 1등급 가전기기의 에너지 절감률이 20%라고 가정했을 때, 누적 탄소 저감량이 2015년에 비해 2022년에 약 316% 증가하는 것으로 나타났다.

• 한국산림과학회지
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• 제110권3호
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• pp.440-452
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• 2021

본 연구는 산림탄소상쇄사업에 참여한 사유림 산주가 지속적으로 참여할 수 있는 조건들을 밝히고자 하였다. 산주가 벌채 시기를 연장하여 온실가스 배출을 늦추는 벌기령 연장형 산림탄소상쇄사업을 지속할 가능성은 산림탄소상쇄권에 대한 보상가격이 높을수록, 산림의 경제적 가치에 대하여 상대적으로 공익적 가치를 더 생각하는 산주일수록, 그리고 교육 수준이 높을수록 증가하는 것으로 나타났다. 산림탄소상쇄권에 대한 수용가능 보상가격(Willingness To Accept, WTA)을 다중양분형 조건부가치평가법을 이용하여 추정한 바, 벌기령을 60년까지 연장할 경우 17,039원/tCO₂이었으며, 벌기령을 100년으로 연장할 경우 23,070원/tCO₂으로 나타났다. 연구 결과에 따라 사유림의 산림탄소상쇄사업 참여와 공급을 확대하기 위해 다음과 같은 방안을 제시할 수 있다. 첫째, 산림탄소상쇄사업을 통해 공편익을 제공하는 사유림 산주가 부담할 수 있는 기회비용에 대한 정책적 지원이 필요하다. 둘째, 숲의 공익가치에 대한 인식과 관심을 제고하기 위한 교육프로그램 등의 방안이 필요하다. 셋째, 제도 초기에 진입한 산주들이 WTA에 대한 수용 및 참여가능성이 낮은 것으로 드러났기 때문에, 초기 진입 산주의 지속적 참여를 이끄는 방안을 모색해야 한다.

• 한국기후변화학회지
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• 제9권4호
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• pp.453-460
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• 2018

The purpose of this study is to analyze the potential quantity of Korean Offset Credits (KOC) resulting from Certified Emission Reductions (CER) in 98 domestic Clean Development Mechanism (CDM) projects that were registered with the United Nations Framework Convention on Climate Change (UNFCCC) as of the end of 2016. Our results show that the total amount of potential KOC is 62,774 kt CO2eq. The potential KOC is only 23.4% of the total CER Issuance. During the first phase, this will be 3.2% of the allocated volume. This is because many projects are related to Renewable Portfolio Standard (RPS), HFC-23, and adipic acid N2O. There is a strong bias in some sectors and projects which could act as market distortion factors. Therefore, it is necessary to expand the target CDM project and activate non CDM offset projects. RPS projects bring fundamental changes to the energy sector, and it is worth reconsidering their acceptability. A wide variety of policy incentives are needed to address strong biases toward certain sectors and projects. The offset scheme has the advantage of allowing entities to reduce their GHG emissions cost effectively through a market mechanism as well as enabling more entities to participate in GHG reduction efforts both directly and indirectly. In contrast, having an inadequate offset scheme range and size might decrease the effort on GHG reduction or concentrate available resources on specific projects. As such, it is of paramount importance to design and operate the offset scheme in such a way that it reflects the situation of the country.

• 한국군사과학기술학회지
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• 제20권5호
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• pp.673-680
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• 2017

In the proposed paper, we designed low noise frequency synthesizer with compact size for Multi-Band. The proposed frequency synthesizer consists of fundamental frequency band(2 GHz) and harmonic frequency band(4 GHz). To improve the phase noise and spurious level of frequency synthesizer, we analyze how the configuration of frequency synthesizer affect the phase noise and design the multi-band's structure. The implemented frequency synthesizer reduce both the phase noise and spurious level. The phase noise is -92.17 dBc/Hz at 1 kHz frequency offset in 2 GHz and -90.50 dBc/Hz at 1 kHz frequency offset in 4 GHz. All spurious signals including fundamental frequency are suppressed at least 20 dBc than the second harmonic frequency.