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우리나라 다목적 대형방제선 건조의 경제적 타당성에 관한 예비평가
장우진,표희동,Chang, Woojin,Pyo, Heedong 해양환경안전학회 2016 海洋環境安全學會誌 Vol.22 No.4
허베이 스피리트호의 유류유출량이 씨프린스호의 것에 비해 2.5배에 불과하지만, 그 경제적 환경적 사회적 피해는 30배에 이를 정도로 대규모 유류유출의 피해는 기하급수적으로 증가할 수 있다. 본 연구에서는 이와 같은 재난적 해양환경오염사고에 신속하고도 효율적으로 대응할 수 있는 다목적 대형방제선의 건조에 대한 기술적 경제적 타당성을 분석함으로써 다목적 대형방제선의 건조에 대한 당위성과 정당성을 확보하고자 한다. 다목적 대형방제선의 기술적 타당성분석과 선진해양국의 많은 사례를 검토한 결과, 4,000톤급의 자항식 호퍼준설선 겸용 방제선을 건조하는 것이 적합한 것으로 판단되었다. 경제적 타당성 분석결과, 가장 보수적인 추정의 B/C ratio는 0.82로 경제성에 미달하지만 자구적 노력을 통하여 경제성을 확보할 수 있다. 한편, 중간추정치와 낙관적 추정치의 B/C ratio는 각각 2.72와 5.82로 이 사업의 경제적 타당성을 충분히 확보할 수 있다. While the amounts of oil spill caused by the VLCC Hebei Spirit indicated 2.5 times more than that of the VLCC Sea Prince, the economic, environmental, and social damages derived from the Hebei Spirit spill were estimated to be about 30 times greater than those from the Sea Prince incident. This study consolidates the appropriate justification for building a multi-purpose large oil spill response vessel to allow swift and efficient handling of catastrophic marine pollution events through an analysis of technical and economic feasibility of such a project. The result of the technical feasibility analysis illustrates that a hopper dredge and oil spill response vessel with a capacity of 4,000 tons should be more appropriate. The result of the economic feasibility analysis indicates that under the most conservative estimates the project appears to be slightly impractical, with a benefit/cost ratio of 0.82, in which self-help efforts, however, can facilitate the project. And medium to optimistic estimates present benefit/cost ratios are estimated to be 2.72 and 5.82 respectively, representing apparent economic feasibility.
W-band MMIC Down-Converter with Image Signal Rejection Using 0.1 ㎛ GaAs MHEMT Technology
장우진(Woojin Chang),이종민(Jong-Min Lee),민병규(Byoung-Gue Min),윤형섭(hyung-Sup Yoon),강동민(Dong-Min Kang) 대한전자공학회 2020 대한전자공학회 학술대회 Vol.2020 No.8
This paper is the first result of a W-band MMIC down-converter with an image signal rejection, which is designed and fabricated using a domestic 0.1 ㎛ MHEMT process technology. The W-band MMIC down-converter is included a low noise amplifier and an image rejection mixer. The W-band MMIC down-converter has an RF input frequency of 93~95 ㎓, a LO input frequency of 92.92 ㎓, an IF output frequency of 80 ㎒, a LO input power of 12 ㏈, an image rejection ratio of 12~15 ㏈, a LO-RF isolation of 35~39 ㏈, and an RF input P1㏈ -19~-17 ㏈m.
64 GHz/50 dBΩ Trans-Impedance Amplifier Design Using Gain-Peaking Inductor for Bandwidth Enhancement
장우진(Woojin Chang),임종원(Jong-Won Lim),강동민(Dong-Min Kang),백용순(Yongsoon Baek) 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.11
This paper is about the design of a trans-impedance amplifier (TIA) capable of 50 Gbps data transmission. In order to enhance a bandwidth, an inductor is used for gain peaking effect in the TIA circuit. It was investigated through equations derived from the simplified common-base amplifier circuits to analyze the gain peaking effect occurring in the inductor in the TIA circuit. To observe the gain peaking effect of the inductor, we used a SiGe 0.13 μm BiCMOS library to design a TIA circuit with inductor and a TIA circuit without inductor. The TIA with inductor has 64 GHz of 3-dB bandwidth, 50 dBΩ of ZT, 163 mW of PDC, and 129 ΩGHz/mW of ZTBW/PDC. Compared with the TIA without inductor, the 3-dB bandwidth of the TIA with inductor is improved by 49 GHz, and it is considered to be applicable to the PAM-4 200 Gbps TROSA capable of transmitting 50 Gbps per channel.
유류오염사고 보상자료를 활용한 해양오염피해비용의 실증분석
장우진(Woojin Chang),허인석(Inseok Heo),이인철(In-Cheol Lee) 한국해양환경·에너지학회 2017 한국해양환경공학회 학술대회논문집 Vol.2017 No.4
본 연구에서는 우리나라에서 발생한 해양오염사고 중 IOPC Funds가 개입한 21건의 사고의 배·보상액 자료를 유출량과의 상관관계를 분석하는 희귀분석방법으로 해양오염피해비용을 실증적으로 분석하였다. IMO에서는 해양안전의 향상을 위한 위험성 평가방법인 FSA를 규정하고 있는데 여기에서 비용편익의 분석은 굉장히 중요한 요소로 유출유의 규모와 피해액과의 상관관계에 대한 연구는 반드시 필요하다. 우리나라의 경우 해양안전을 위한 적절한 의사결정체계를 보유하고 있지 않다. 이에 해양오염피해에 대한 경제성평가 등을 위한 피해비용분석은 관련 분야(해양오염사고, 선박사고, 침몰사고 등)를 연구함에 있어 중요한 기초자료를 제공할 수 있을 것이다. In this paper, provide and empirical analysis of cost of twenty-one oil spill incidents with spill volume by regression analysis provided by the International Oil Pollution Compensation Funds data in Korea. IMO is utilizing Formal Safety Assessment (FSA) that is the major risk assessment tool that is being used for policy-making within the IMO. Most important factor on FSA is the Cost-Benefic analysis. It is necessary to research found to be the relationship between spill volume and spill cost. Unfortunately, there is no appropriate policy-making system on the marine safety with environment in Korea. This research will be able to provide fundamental data on the field of cost-benefit analysis with the marine pollution incident`s issues.
GaN HEMT 대면적 소자 모델링을 위한 DC 바이어스 조건에 따른 게이트 채널 위치별 발생 온도 특성 분석
장우진(Woojin Chang),강동민(Dong-Min Kang),이상훈(Sang-Hun Lee) 대한전자공학회 2021 대한전자공학회 학술대회 Vol.2021 No.6
This paper presents the temperature distribution analysis of gate channels of GaN large-sized HEMT for different DC bias conditions by using an infrared microthermal measurement system. It is analyzed that the temperature difference between locations of the gate channels at high power is significant, and the results of the measurement and analysis need to be considered in designing or modeling high-power active devices.
필드 플레이트 구조에 대한 GaN FET 항복전압특성 영향
장우진(Woojin Chang),김정진(Jeong-Jin Kim),배성범(Sung-Beom Bae),박영락(Young-Rak Park),문재경(Jae-Kyoung Mun),고상춘(Sang-Chun Ko) 대한전자공학회 2015 대한전자공학회 학술대회 Vol.2015 No.6
This paper presents various field plates (FPs) fabricated on GaN Field Effect Transistors (FETs) using AlGaN/GaN on sapphire substrates. GaN FETs with six different FPs were fabricated to compare with their FPs and lengths of FPs in terms of their breakdown voltage characteristics. The fabricated GaN FET with the gamma-shaped gate FP exhibited a breakdown voltage of 1190 V for a gate-to-drain spacing of 15㎛, while the GaN FET without any FP (a planar gate) showed a breakdown voltage of 1050 V for the same gate-to-drain spacing. For the GaN FETs with 10㎛ gate-to-drain spacing and gamma-shaped gate FPs, they were varied 0~2 ㎛ in the length of the gamma-shaped gate FPs and the GaN FET with 0.5㎛-length gamma-shaped gate FP showed more 50~140 V than the others. And in another processed wafer, the GaN FET with the source FP and the gamma-shaped FP together had a breakdown voltage of 1480 V more than 870 V with only the source FP for a gate-to-drain spacing of 16㎛.
높은 항복전압(>1,000 V)을 가지는 Circular β-Ga<sub>2</sub>O<sub>3</sub> MOSFETs의 특성
조규준,문재경,장우진,정현욱,Cho, Kyu Jun,Mun, Jae-Kyong,Chang, Woojin,Jung, Hyun-Wook 한국전기전자재료학회 2020 전기전자재료학회논문지 Vol.33 No.1
In this study, MOSFETs fabricated on Si-doped, MBE-grown β-Ga<sub>2</sub>O<sub>3</sub> are demonstrated. A Si-doped Ga<sub>2</sub>O<sub>3</sub> epitaxial layer was grown on a Fe-doped, semi-insulating 1.5 cm × 1 cm Ga<sub>2</sub>O<sub>3</sub> substrate using molecular beam epitaxy (MBE). The fabricated devices are circular type MOSFETs with a gate length of 3 ㎛, a source-drain spacing of 20 ㎛, and a gate width of 523 ㎛. The device exhibited a good pinch-off characteristic, a high on-off drain current ratio of approximately 2.7×10<sup>9</sup>, and a high breakdown voltage of 1,080 V, which demonstrates the potential of Ga<sub>2</sub>O<sub>3</sub> for power device applications including electric vehicles, railways, and renewable energy.
고전압 β-산화갈륨(β-Ga<sub>2</sub>O<sub>3</sub>) 전력 MOSFETs
문재경,조규준,장우진,이형석,배성범,김정진,성호근,Mun, Jae-Kyoung,Cho, Kyujun,Chang, Woojin,Lee, Hyungseok,Bae, Sungbum,Kim, Jeongjin,Sung, Hokun 한국전기전자재료학회 2019 전기전자재료학회논문지 Vol.32 No.3
This report constitutes the first demonstration in Korea of single-crystal lateral gallium oxide ($Ga_2O_3$) as a metal-oxide-semiconductor field-effect-transistor (MOSFET), with a breakdown voltage in excess of 480 V. A Si-doped channel layer was grown on a Fe-doped semi-insulating ${\beta}-Ga_2O_3$ (010) substrate by molecular beam epitaxy. The single-crystal substrate was grown by the edge-defined film-fed growth method and wafered to a size of $10{\times}15mm^2$. Although we fabricated several types of power devices using the same process, we only report the characterization of a finger-type MOSFET with a gate length ($L_g$) of $2{\mu}m$ and a gate-drain spacing ($L_{gd}$) of $5{\mu}m$. The MOSFET showed a favorable drain current modulation according to the gate voltage swing. A complete drain current pinch-off feature was also obtained for $V_{gs}<-6V$, and the three-terminal off-state breakdown voltage was over 482 V in a $L_{gd}=5{\mu}m$ device measured in Fluorinert ambient at $V_{gs}=-10V$. A low drain leakage current of 4.7 nA at the off-state led to a high on/off drain current ratio of approximately $5.3{\times}10^5$. These device characteristics indicate the promising potential of $Ga_2O_3$-based electrical devices for next-generation high-power device applications, such as electrical autonomous vehicles, railroads, photovoltaics, renewable energy, and industry.