• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.277-278
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• 2006

This paper presents circuit models and control algorithms of distributed generation system(DGS) which consists of Z-type converter and PWM inverter Z-type converter which employs both the L and C passive components and shoot-through zero vectors instead of the conventional DC/DC converter in order to step up DC-link voltage. Discrete time sliding mode control with the asymptotic observer is used for current control.

• Molecules and Cells
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• v.28 no.1
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• pp.57-65
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• 2009

CDC48 is a member of the AAA ATPase superfamily. Yeast CDC48 and its mammalian homolog p97 are implicated in diverse cellular processes, including mitosis, membrane fusion, and ubiquitin-dependent protein degradation. However, the cellular functions of plant CDC48 proteins are largely unknown. In the present study, we performed virus-induced gene silencing (VIGS) screening and found that silencing of a gene encoding a tobacco CDC48 homolog, NgCDC48, resulted in severe abnormalities in leaf and shoot development in tobacco. Furthermore, transgenic tobacco plants (35S:anti-NgCDC48), in which the NgCDC48 gene was suppressed using the antisense RNA method, exhibited severely aberrant development of both vegetative and reproductive organs, resulting in arrested shoot and leaf growth and sterile flowers. Approximately 57-83% of 35S:anti-NgCDC48 plants failed to develop mature organs and died at early stage of development. Scanning electron microscopy showed that both adaxial and abaxial epidermal pavement cells in antisense transgenic leaves were significantly smaller and more numerous than those in wild type leaves. These results indicate that NgCDC48 is critically involved in cell growth and development of tobacco plants. An in vivo targeting experiment revealed that NgCDC48 resides in the endoplasmic reticulum (ER) in tobacco protoplasts. We consider the tantalizing possibility that CDC48-mediated degradation of an as-yet unidentified protein(s) in the ER might be a critical step for cell growth and expansion in tobacco leaves.

• The Journal of Korean Society for Radiation Therapy
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• v.25 no.1
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• pp.25-31
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• 2013

Purpose: The aim of this study is to evaluate the dosimetric properties of robust planning strategy for plain intensity-modulated proton therapy (IMPT) taking into account of the uncertainties of effective proton range and set up error as compared to photon intensity-modulated radiation therapy (photon-IMRT) in prostate cancer treatment. Materials and Methods: The photon-IMRT (7 beams, step & shoot), plain-IMPT (2, 4, and 7 portals), and robust- IMPT plans, which was recalculated the plain-IMPT based on the uncertainties of range error (${\pm}5%$) and set up error (0.5 cm), were evaluated for five prostate cancer patients prescribed by 70 Gy/35 fractions. To quantitatively evaluate the dose distributions, several parameters such as maximum dose, minimum dose, mean dose, conformity index (CI), and homogeneity index (HI) for PTV as well as dose-volume index of VxGy for OARs were calculated from dose-volume histograms. Results: Robust-IMPT showed superior dose distributios in the PTV and OARs as compared to plain-IMPT and photon-IMRT. Like plain-IMPT, robust-IMPT were resulted in dose fluctuation around OARs, while better homogeneity and conformity in PTVs and lower mean dose in OARs as compared to photon-IMRT. Conclusion: In consideration with the effective range correction and set up movement using robustness in IMPT plan, the dosimetric uncertainties from plain-IMPT could substantially reduce and suggest more effective solutions than photon-IMRT in prostate cancer treatment.

• Journal of Radiation Protection and Research
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• v.36 no.1
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• pp.28-34
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• 2011

The measurement-based verification for intensity modulated radiation therapy (IMRT) is a time-and labor-consuming procedure. Instead, this study aims to develop a MU fluence reconstruction method for IMRT QA. Total actual fluences from treatment planning system (TPS, Eclipse 8.6, Varian) were selected as a reference. Delivered leaf positions according to MU were extracted by the dynalog file generated after IMRT delivery. An in-house software was develop to reconstruct MU fluence from the acquired delivered leaf position data using MATLAB. We investigated five patient's plans delivered by both step-and-shoot IMRT and sliding window technologies. The total actual fluence was compared with the MU fluence reconstructed by using commercial software (Verisoft 3.1, PTW) and gamma analysis method (criteria: 3%/3 mm and 2%/1 mm). Gamma pass rates were $97.8{\pm}1.33$% and the reconstructed fluence was shown good agreement with RTP-based actual fluence. The fluence from step and shoot IMRT was shown slightly higher agreement with the actual fluence than that from sliding window IMRT. If moving from IMRT QA measurements toward independent computer calculations, the developed method can be used for IMRT QA. A point dose calculation method from reconstructed fluences is under development for the routine IMRT QA purpose.

• The Journal of the Korea Contents Association
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• v.16 no.3
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• pp.219-231
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• 2016

$^{99m}Tc$-DMSA planar scan that can analyze the functions of kidney quantitatively provides less information on a lesion than tomography scanning. Therefore, this study applied a high sensitivity all-purpose collimator that is sensitive to photonic signals to $^{99m}Tc$-DMSA and carried out a clinical scan with single photon emission computed tomography (SPECT). And diagnostic accuracy and time requirement of were analyzed to know the clinical usefulness of the applied scanning method. 10 subjects were intravenously injected with radiopharmaceutical product (1.0-1.2 MBq/kg) and scanned by a gamma camera with planar scanner (high resolution (HR)-mode, $256{\times}256$, 50 kcts/view, 4 image) and SPECT (HR / high sensitive (HS)-mode, $128{\times}128$, step and shoot, $180^{\circ}$, variable sec/angle, total 64 frame, OSEM reconstruction), respectively. The collected data was compared with an analysis program. The results showed that HS-mode SPECT detected total counts 1.8-5.6 times more than planar scan. Relative renal function evaluated based on the counts was not significantly different by two scanning methods (p=0.96) and it turned out that test time was shortened by 39% when HS-mode SPECT was used. Therefore, SPECT using HR, HS-mode collimator could analyze renal function more quantitatively than using planar scan and the former could diagnose the location information of a lesion more accurately than the latter as well as shortened test time requirement, which demonstrated the clinical usefulness of $^{99m}Tc$-DMSA renal SPECT using high sensitivity all purpose collimator.

• Journal of Plant Biotechnology
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• v.42 no.1
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• pp.49-54
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• 2015

Based on the results in this study, here we propose a systematic micropropagation process for 'Gisela 5' that is one of the important dwarfing cherry rootstocks. When the apical tips detached from newly developed shoot in spring season were cultured on the half strength MS media with 0.5 mg/L IBA and 0.5 ~ 1.0 mg/L BA, the cultures scored the highest acquisition rate at 90% for normal shoot with vigorous growth and without hyperhydricity. As next step, the young shoots maintained in vitro well multiplied on the full strength MS medium supplemented with 0.5 mg/L IBA and 0.5 mg/L BA, in which multiplication rate was approximately nine-fold. Given the half strength MS medium containing 2.0 mg/L IBA, each transplanted shoot further developed robust roots. Finally, the plantlets were easily acclimatized in the compost consisted of vermiculite, perlite, and peatmoss in the proportion of 1:1:1. We expect that the results are useful for cherry cultivation and its rootstock production.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1055-1057
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• 2002

산업이 발전할수록 정밀 위치제어 알고리즘에 대한 요구가 증가하고 있으며, 선형 전동기의 보급에 따라 1um 단위의 고급 위치 제어 알고리즘에 대한 중요성이 커지고 있다. 위치제어에 있어서 작업의 신속성 및 정밀도를 높이기 위해서는 제어의 오버슛 현상을 억제할 필요가 있으며, 현장에서 직접 활용이 가능하도록 하려면 보다 간단한 구조의 제어 알고리즘이 요구된다. 위치제어에서 가장 큰 문제는 전동기의 최대 속도 및 최대 전류 제한에 의한 비선형성이 위치의 과도한 오버슛으로 나타난다는 것이며, 기존의 고급 알고리즘에서는 미리 제공되는 S-커브 형태의 위치 명령 패턴을 사용하여 속도 및 전류 제한을 회피하고 있다. 본 연구에서는 고급 제어 알고리즘과 동일한 성능을 내면서 복잡한 패턴 생성기를 사용하지 않고도 실제 위치가 오버슛없이 부드러운 S-커브 형태로 목표값에 수렴하는 새로운 형태의 위치제어기를 제안한다. 제안된 제어기는 비교적 간단한 구조로 인하여 헌장 적용력이 매우 뛰어나며, 이득 설정이 간편하다는 장점을 지니고 있다.

• Journal of Forest and Environmental Science
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• v.24 no.2
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• pp.79-88
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• 2008

Twenty-eight of 44 Indian Ceropegia species are endemic and their survival is threatened. As a step towards conservation, we implied in vitro methods for the sustainable propagule production in C. hirsuta, C. lawii, C. maccannii, C. oculata and C. sahyadrica. Effects of explant, growth regulators, sucrose and photoperiod were studied. High frequency microtuber production was achieved with the seedling-apical buds, grown on MS medium containing 4-6 mg $1^{-1}$ BAP, 3-8% (w/v) sucrose, under continuous illumination. Each microtuber, when subcultured proliferated to form a cluster of secondary microtubers. Every primary and secondary microtuber bore at least one shoot-bud and a root primordium. Each tuber (formed with any of the significantly effective treatments) weighed more than 500 mg, enough to plant directly in non-sterilized soils. Microtubers could be produced and proliferated round the year. Proliferation could be solely attributed to in vitro procedures as these plants bear solitary tubers in vivo. Microtubers could be sprouted in vitro to prepare ready to pot plantlets. As, this novel method succeeded for all five species, though they belong to different eco-physiological backgrounds, we recommend its implementation in the conservation programs for a broader range of Ceropegia species, supported by other integrated strategies.

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.118-124
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• 1995

단일광자방출전산화 단층촬영술을 이용한 영상정보를 효과적으로 얻기 위하여 고려되어야 할 사항으로는 1) 조준기(collimator)의 선택, 2) 기질(matrix)의 크기, 3) 회전각의 수 (number of angles), 4) 360도 또는 180도 획득(acquisition), 5) continuous 또는 step& shoot, 6) 원형 또는 비원형회전 등이 있다. 저자들은 비원형회전으로 검체와 검출기 사이의 거리를 단축시킴으로써 직선성, 균일성, 대조도, 해상력에 미치는 영향을 알아보기 위하여 원형회전 방법과 비교하여 다음과 같은 결과를 얻었다. (1) 비원형회전을 하여도 균일성(uniformity)과 직선성(linearlity)을 유지한다. (2) 균일성, 대조도(contrast), 해상력(resolution)들이 비원형 회전을 한 경우에 보다 더 개선되었다. (3) 영상 획득시간은 비원형회전인 경우에 더 소요되었다. (매스캔 당 10분) 따라서 검사자는 영상 화질의 개선효과와 상반되는 보정(calibration)과 설치(set-up)에 소요되는 시간(매스캔당 10분이상)을 비교하여 자료획득(data acquisition) 회전방법을 선택하여야한다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.169-172
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• 2007

This paper presents circuit models and control algorithms of distributed generation system(DGS) which consists of Z-type converter and PWM inverter. Z-type converter which employs both the L and C passive components and shoot-through zero vectors instead qf the conventional DC/DC converter in order to step up DC-link voltage. Discrete time sliding mode control with the asymptotic observer is used for current control. This system am be used for power conversion of DC renewable energy.