• 제목/요약/키워드: PLF

검색결과 50건 처리시간 0.027초

공명기를 이용한 소형위성발사체 탑재부의 음향하중 저감 (Acoustic Load Reduction in the Payload of Small Launch Vehicle by using Resonators)

  • 서상현;정호경;박순홍;장영순;이영무
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 춘계학술대회논문집
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    • pp.234-237
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    • 2007
  • To protect a satellite and electronic equipment from the acoustic load generated by rocket propulsion system, many launch vehicle use acoustic blanket. Acoustic load is main source of random vibration working on the payload. Most high frequency region of the acoustic loads is reduced by payload fairing skins and acoustic blanket, but low frequency region is not. In order to reduce acoustic load of low frequency region, we designed array resonator panel which was made of composite materials. Insertion loss capacity of the payload fairing with acoustic blanket was verified from PLF acoustic test in the acoustic chamber.

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확률론적 기법을 이용한 시변 ATC 용량 결정 (Probabilistic approach to time varying Available Transfer Capability calculation)

  • 신동준;이준경;이효상;김진오;정현수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 하계학술대회 논문집 A
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    • pp.645-647
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    • 2004
  • According to NERC definition, Available Transfer Capability (ATC) is a measure of the transfer capability remaining in the physical transmission network for the future commercial activity To calculate ATC, accurate and defensible TTC, CBM and TRM should be calculated in advance. This paper proposes a method to quantify time varying ATC based on probabilistic approach. The uncertainties of power system and market are considered as complex random variables. TRM with the desired probabilistic margin is calculated based on PLF analysis, and CBM is evaluated using LOLE of the system. Suggested ATC quantification method is verified using IEEE RTS with 72 bus. The proposed method shows efficiency and flexibility for the quantification of ATC.

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Estimation of entropy of the inverse weibull distribution under generalized progressive hybrid censored data

  • Lee, Kyeongjun
    • Journal of the Korean Data and Information Science Society
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    • 제28권3호
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    • pp.659-668
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    • 2017
  • The inverse Weibull distribution (IWD) can be readily applied to a wide range of situations including applications in medicines, reliability and ecology. It is generally known that the lifetimes of test items may not be recorded exactly. In this paper, therefore, we consider the maximum likelihood estimation (MLE) and Bayes estimation of the entropy of a IWD under generalized progressive hybrid censoring (GPHC) scheme. It is observed that the MLE of the entropy cannot be obtained in closed form, so we have to solve two non-linear equations simultaneously. Further, the Bayes estimators for the entropy of IWD based on squared error loss function (SELF), precautionary loss function (PLF), and linex loss function (LLF) are derived. Since the Bayes estimators cannot be obtained in closed form, we derive the Bayes estimates by revoking the Tierney and Kadane approximate method. We carried out Monte Carlo simulations to compare the classical and Bayes estimators. In addition, two real data sets based on GPHC scheme have been also analysed for illustrative purposes.

다중 Port로 연결된 다중 격실 Vent 해석 기법 개발 (Development of a Vent Analysis Method for Multiple Compartments Connected Through Multiple Ports)

  • 옥호남;김인선
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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    • pp.547-550
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    • 2006
  • An analysis method is developed for the prediction of venting in multiple compartments which are connected in series or parallel through multiple ports. The existing method by the authors is modified to remove the limitation in number of ports and compartments, and the more general polytropic relation or solution of the additional energy equation replaces the previous isentropic relation allowing the prediction of pressure rise in addition to pressure drop. The accuracy of the method is verified by comparison with the results by NASA Flap code for the problem of pressure drop in a payload in the Space Shuttle cargo bay. It is expected that this method will be a useful tool in prediction of the pressure variation in a payload or payload capsule without mentioning the payload fairing itself.

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확률론적 조류계산을 이용한 송전 신뢰도 여유 계산 (Calculate Transmission Reliability Margin using Probabilistic Load Flow)

  • 신동준;김진오;김규호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 A
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    • pp.569-571
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    • 2003
  • As a definition of NERC, Available Transfer Capability(ATC) is a measure of the transfer capability remaining in the physical transmission network for the future commercial activity. To calculate ATC, accurate and defensible TTC, CBM and TRM should be calculated in advance. In this paper, we propose a method to quantify TRM using probabilistic load flow based on the method of moment. Generation output, bus voltages, loads, and line outages are considered as complex random variables (CRV) to take into account for uncertainties related to the transmission network conditions. Probability Density Function (PDF) of line flow at the most limiting line is used to quantify TRM with the desired probabilistic margin. Suggested method is compared with the results from conventional CPF method and verified using 24 bus MRTS, and the suggested method based on PLF shows efficiency and flexibility for the quantification of TRM compared with the conventional method.

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토지이용도가 다른 소유역별 유입하천에서 용존유기물 형광특성 변화 (Change in Fluorescence Characteristics of Dissolved Organic Matter at Inflow Stream per Catchment of Different Land Use)

  • 김세원;오종민;이보미;최광순
    • 생태와환경
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    • 제44권3호
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    • pp.292-302
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    • 2011
  • 본 연구는 공단, 도심 및 농촌유역의 서로 다른 유역특성을 갖고 있는 시화호 유역을 대상으로 형광분석을 통해 각 소유역 유입하천에서의 오염물질 유출특성을 분석하였다. 4TG는 강우시 시공간적 오염물질 유출특성 분석 결과, 초기세척효과가 강하게 나타나 강우초기 단백질 및 휴믹계열의 고농도의 오염물질이 빠르게 유출된 후, 다시 유량증가에 따른 희석효과로 인해 오염물질 유출농도가 급격하게 감소하는 유출특성을 나타내고 있다. AS는 다른 도심유역 하천들이 갖고 있는 강우시 오염물질 유출 특성과는 다른 양상을 나타내고 있다. 토지이용특성상 도심유역 특성을 나타내고 있지만, 신도시 조성시 하천주변에 공원과 수변완충지역이 조성되어 있어 강우시 오염물질 유출속도를 저감시키는 역할을 하고, 단백질계열의 오염물질과 함께 휴믹계열의 오염물질도 함께 유출되는 유출특성을 나타내고 있다. MS는 입자성 오염물질과 함께 단백질계열의 오염물질 유입 현상이 뚜렷하게 나타나고 있어 단백질계열의 오염물질 저감방안이 함께 수립되어야 한다. 농촌유역 하천은 초기세척효과가 나타나지 않고, 후기유출현상이 강하기 때문에 충분한 사전 조사를 통해 오염물질이 최고농도에 도달하는 시점을 대상으로 선택적인 유역관리가 필요하다.

Characterization, Cloning and Expression of the Ferritin Gene from the Korean Polychaete, Periserrula leucophryna

  • Jeong Byeong Ryong;Chung Su-Mi;Baek Nam Joo;Koo Kwang Bon;Baik Hyung Suk;Joo Han-Seung;Chang Chung-Soon;Choi Jang Won
    • Journal of Microbiology
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    • 제44권1호
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    • pp.54-63
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    • 2006
  • Ferritin is a major eukaryotic protein and in humans is the protein of iron storage. A partial gene fragment of ferritin (255 bp) taken from the total RNA of Periserrula leucophryna, was amplified by RT-PCR using oligonucleotide primers designed from the conserved metal binding domain of eukaryotic ferritin and confirmed by DNA sequencing. Using the $^{32}P-labeled$ partial ferritin cDNA fragment, 28 different clones were obtained by the screening of the P. leucophryna cDNA library prepared in the Uni-ZAP XR vector, sequenced and characterized. The longest clone was named the PLF (Periserrula leucophryna ferritin) gene and the nucleotide and amino acid sequences of this novel gene were deposited in the GenBank databases with accession numbers DQ207752 and ABA55730, respectively. The entire cDNA of PLF clone was 1109 bp (CDS: 129-653), including a coding nucleotide sequence of 525 bp, a 5' -untranslated region of 128 bp, and a 3'-noncoding region of 456 bp. The 5'-UTR contains a putative iron responsive element (IRE) sequence. Ferritin has an open reading frame encoding a polypeptide of 174 amino acids including a hydrophobic signal peptide of 17 amino acids. The predicted molecular weights of the immature and mature ferritin were calculated to be 20.3 kDa and 18.2 kDa, respectively. The region encoding the mature ferritin was subcloned into the pT7-7 expression vector after PCR amplification using the designed primers and included the initiation and termination codons; the recombinant clones were expressed in E. coli BL21(DE3) or E. coli BL21(DE3)pLysE. SDS-PAGE and western blot analysis showed that a ferritin of approximately 18 kDa (mature form) was produced and that by iron staining in native PAGE, it is likely that the recombinant ferritin is correctly folded and assembled into a homopolymer composed of a single subunit.

생분해에 의한 용존 자연유기물질 분광특성 및 Pyrene 결합반응성 변화 (Changes in Spectroscopic Characteristics and Pyrene Binding Reactivities of Dissolved Organic Matters By Biodegradation)

  • 박민혜;허진
    • 대한환경공학회지
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    • 제30권9호
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    • pp.893-899
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    • 2008
  • 본 연구에서는 낙엽과 토양에서 추출한 용존 자연유기물질(DOM)을 대상으로 생분해 과정 중 변화하는 분광특성과 pyrene 결합 반응성을 조사하였다. 유기물질 특성 변화 분석을 위해 용존 유기탄소(DOC), 용존 자연유기물질 내 방향족 탄소성분을 나타내는 고유흡광도(Specific UV absorbance: SUVA), synchronous 형광 스펙트럼과 유기탄소결합계수(pyrene organic carbon-normalized binding coefficient: K$_{oc}$) 분석을 실시하였다. 3주간의 배양기간 동안 낙엽 추출 DOM과 토양 DOM의 DOC는 각각 61%, 51% 감소하였다. 배양 전과 후의 분광특성을 비교해 보면 단백질/아미노산 계 형광특징(PLF)은 점차 감소된 반면 SUVA, 펄빅산계 형광 특징(FLF)과 휴믹산 계 형광 특징(HLF)은 점차 증가하였다. 이러한 자연유기물질의 분광특성 변화는 생분해 과정을 통해 휴믹화가 진행되며 자연유기물질 내 비방향족 생분해성 탄소성분이 단단한 구조의 방향족 탄소구조로 변화됨을 시사한다. SUVA 값과 유기오염물질과의 결합정도를 나타내는 K$_{oc}$ 값 사이에서는 시료의 종류와 상관없이 1차 상관관계(r = 0.97)를 보여 주어 생분해가 진행되는 동안 방향족 탄소구조 분포가 자연유기물질의 소수성 오염물질과의 결합 정도에 큰 영향을 미침을 보여주었다. 또한 형광특징 중 FLF와 HLF가 K$_{oc}$ 값과 높은 상관관계를 보였으며 자연유기물질의 기원에 따라 다른 상관관계식을 보여주었다. 본 연구를 통해 생분해가 진행되는 동안 자연유기물질 성분변화 및 소수성 유기오염물질의 거동 예측에 자연유기물질의 분광특성이 좋은 모니터링 지표로 사용될 수 있음을 보여 주었다.

Glycididazole Sodium Combined with Radiochemotherapy for Locally Advanced Nasopharyngeal Carcinoma

  • Li, Ming-Yi;Liu, Jin-Quan;Chen, Dong-Ping;Qi, Bin;Liang, Yu-Ying;Yin, Wen-Jing
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권6호
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    • pp.2641-2646
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    • 2014
  • Background: To evaluate efficacy and side effects of glycididazole sodium (CMNa) combined with chemotherapy (cisplatin plus 5-FU/folic acid, PLF) and radiotherapy in treating patients with locally advanced nasopharyngeal carcinoma. Materials and Methods: Patients with III~IV stage nasopharyngeal carcinoma (NPC),were randomly divided into treatment group (46 patients) and control group (45 patients). Both groups received radiotherapy concomitant with PLF chemotherapy. The treatment group at the same time cwas given CMNa ($800mg/m^2$ before radiotherapy), by l h intravenous drip, three times a week. Results: When the dose of radiation was over 60 Gy, complete response rates of nasopharyngeal tumor and lymph node metastases in treatment group were significantly higher than in the control group (93.5% vs 77.8%; 89.1% vs 93.5%, p<0.05). Three months after radiotherapy, complete response rate of nasopharynx cancer and lymph node metastases in treatment group was both 97.8%, again higher than in the control group (84.4% and 82.2%) (p<0.05). In the treatment group, 1, 3, 5 year disease-free survival rates were 95.7%, 86.7% and 54.5%; and in control group, the corresponding disease-free survival rates were 93.3%, 66.2% and 38.6%, respectively, the difference being statistically significant (log-rank =5.887, p=0.015). One, 3, 5 year overall survival rates in two groups of patients were 97.8%, 93.5%, 70.4% and 95.5%, 88.07%, 48.4%, respectively, again with a statistically significant difference (log-rank=6.470, p=0.011). Acute toxicity and long-term radiotherapy related toxicity in the two groups did not differ (p>0.05). Conclusions: Glycididazole sodium could improve curative effects without increasing adverse reactions when treating paitents with locally advanced nasopharyngeal carcinoma.

기원별 용존 유기물의 분광특성 및 COD 산화율 비교 (Comparison of Spectroscopic Characteristics and Chemical Oxygen Demand Efficiencies for Dissolved Organic Matters from Diverse Sources)

  • 정가영;박민혜;허진;이승윤;신재기
    • 한국물환경학회지
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    • 제25권4호
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    • pp.589-596
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    • 2009
  • The spectroscopic characteristics and chemical oxygen demand (COD) oxidation efficiencies were investigated for dissolved organic matters (DOM) from diverse sources, which may indirectly affect the concentrations and the quality of DOM found in watersheds. The DOM investigated for this study showed a wide range of the percent distributions of refractory organic matter (R-OM) from 8 to 100%. Relatively high R-OM distributions were observed for the DOM with the source of head water, sediments, paddy soils, field soils, and treated sewage whereas the DOM from livestock waste, reed, weeds, algae, and attached algae exhibited lower R-OM percent distributions. The percent distribution of R-OM had positive correlations with specific UV absorbance (SUVA) and humidification indices (HIX) of DOM. The investigated DOM was classified into four different source groups (i.e., biota, vegetables, soils, sediments) by comparing the synchronous fluorescence spectra. The DOM group from biota source was characterized by a prominent presence of protein-like fluorescence (PLF) whereas fulvic-like fluorescence (FLF) was additionally observed for vegetable-source DOM. FLF became significant for the DOM from both soils and sediments although no PLF was found for soil-derived DOM. A range of COD oxidation efficiency was observed for the various DOM, ranging from 36 to 94% and from 65 to 125% for $COD_{Mn}$ and $COD_{Cr}$, respectively. The results indicate that $COD_{Cr}$ reflects the higher OM concentration than $COD_{Mn}$. However, 95% confidence intervals of the COD oxidation efficiencies were similar for the two types of COD, suggesting that $COD_{Cr}$ may not be the superior OM index to $COD_{Mn}$ in terms of the variability of the oxidation efficiency. No significant correlations were obtained between COD oxidation efficiencies and the spectroscopic characteristics of DOM for this study.