• Journal of the Korea Academia-Industrial cooperation Society
• /
• 제10권12호
• /
• pp.3587-3593
• /
• 2009

Nowadays, the PV systems have been focused on the interconnection between the power source and the grid. The PV inverter, either single-phase or three-phase, can be considered as the core of the whole system because of an important role in the grid-interconnecting operation. An important issue in the inverter control is the load current regulation. In the literature, the Proportional+Integral (PI) controller, normally used in the current-controlled Voltage Source Inverter (VSI), cannot be a satisfactory controller for an ac system because of the steady-sate error and the poor disturbance rejection, especially in high-frequency range. By comparison with the PI controller, the Proportional+Resonant (PR) controller can introduce an infinite gain at the fundamental ac frequency; hence can achieve the zero steady-state error without requiring the complex transformation and the dq-coupling technique. In this paper, a PR controller is designed and adopted for replacing the PI controller. Based on the theoretical analyses, the PR controller based control strategy is implemented in a 32-bit fixed-point TMS320F2812 DSP and evaluated in a 3kW experimental prototype Photovoltaic (PV) power conditioning system (PCS). Simulation and experimental results are shown to verify the performance of implemented control scheme in PV PCS.

• Journal of Bio-Environment Control
• /
• 제20권1호
• /
• pp.40-44
• /
• 2011

This study was conducted to develop method of producing okra in the plastic house and the 11 cultivar of okra were planted in plastic house for selecting proper cultivar in Korea. As result of observing growth, commercial cultivar germinated better than wild collected. The germination rate in 'No 1', 'No 4' and 'No 5' were better than in 'No 2' and 'No 3'. The plant height of 'No. 4', which is one of wild collected, showed biggest plant height moreover 'Greensode'. The numbers of node, which could indicate to set fruit, showed 4.2~6.5 per plant in most cultivar and 'No 2' and 'No 5' could yield more than others. 'Greensode' was planted in plastic house for finding out suitable planting method. The seeds were soaked could germinate 100% and those were taken 8 days for germinating but control seeds needed 15 days to germinate. The yield of 'Greensode' which was planted in $45{\times}75cm$ with planted 3 and 4 per hill could best produce in plastic house.

• Progress in Medical Physics
• /
• 제14권3호
• /
• pp.151-160
• /
• 2003

The application of more complex radiotherapy techniques using multileaf collimation (MLC), such as 3D conformal radiation therapy and intensity-modulated radiation therapy (IMRT), has increased the significance of verifying leaf position and motion. Due to thier reliability and empirical robustness, quality assurance (QA) of MLC. However easy use and the ability to provide digital data of electronic portal imaging devices (EPIDs) have attracted attention to portal films as an alternatives to films for routine qualify assurance, despite concerns about their clinical feasibility, efficacy, and the cost to benefit ratio. In this study, we developed method for daily QA of MLC using electronic portal images (EPIs). EPID availability for routine QA was verified by comparing of the portal films, which were simultaneously obtained when radiation was delivered and known prescription input to MLC controller. Specially designed two-test patterns of dynamic MLC were applied for image acquisition. Quantitative off-line analysis using an edge detection algorithm enhanced the verification procedure as well as on-line qualitative visual assessment. In conclusion, the availability of EPI was enough for daily QA of MLC leaf position with the accuracy of portal films.

• Journal of Conservation Science
• /
• 제36권3호
• /
• pp.178-186
• /
• 2020

Verdigris is a traditional artificial pigment reported on old research papers and according to the methods mentioned in the literature, it is manufactured by the corrosion of copper or copper alloys using vinegar and by further scraping the generated rust. Since the Three Kingdoms Period, various household products with copper alloys, such as bronze and brass, have been used, and pigment analysis of these cultural heritage items has revealed the presence of tin, zinc, lead, and copper in green pigments. Based on these data, five types of verdigris were prepared from copper and copper alloys, and analyzed. the analysis results revealed a bluish green pigmentation, and the chromaticity, particle shape, and oil absorption quantity of each verdigris differed based on the type of copper alloy used in its preparation. The main components of verdigris are Cu, Sn, Zn and Pb, and their proportions depended on the type of copper alloy used during manufacturing. However, the main constituent mineral of the pigments is the same as 'hoganite[Cu(CH₃COO)₂·H₂O]', regardless of the copper alloy used. The result of accelerated weathering test for stability evaluation revealed that verdigris was discolored rapidly, thereby indicating that its stability was low, in particular, the pigments comprising lead presented relatively lower stability.

• Korean Journal of Animal Reproduction
• /
• 제23권3호
• /
• pp.213-220
• /
• 1999

The litter size has been the primary interest of economic traits in pig reproduction. It has been recently shown that insulin-like growth factor-Ⅰ(IGF-Ⅰ) plays roles in establishing pregnancy and in supporting fetal growth and development. But, the effect of serum IGF-Ⅰ on litter size has not been studied. Therefore, this study was conducted to relate serum IGF-Ⅰ concentration with porcine litter size and to investigate the possible connection with estrogen receptor(ER) as a candidate gene for the litter size. Sera during day 45 to 105 of pregnancy were collected from two groups showing high and low litter size and serum IGF-Ⅰ concentration was measured by radioimmunoassay (RIA). IGF-Ⅰ levels in both groups decreased gradually as pregnancy stage proceeded but were not significantly different. Secondly, DNA was extracted from blood and PCR-RFLP was utilized to analyze ER genotypes of pigs in each group, which produced three polymorphic patterns. Based on the ER genotypes analyzed, low litter size group showed higher IGF-Ⅰ concentration than high litter size group. Taken together, the results indicate that the serum IGF system was correlated with steroid system but not with the litter size in pigs. Thus, this study implies that porcine litter size could be determined locally at the ovary level.

• Proceedings of the Korea Technology Innovation Society Conference
• /
• 한국기술혁신학회 1998년도 춘계정기학술대회
• /
• pp.9-9
• /
• 1998

지난 수년동안 정부출연(연)의 연구개발활동의 효율화를 도모하기 위하여 정부와 과학기술계에서 논의되어 왔던 출연(연)의 석박사 교육과정 설립에 관하여 출연(연)관련자들의 의견을 모아 구체적인 설립모델을 제시하였다. 먼저 정부출연(연)에 석박사 교육과정 설치가 필요한 이유와 기대효과를 제시하고, 다음으로 단설대학원의 설립모델로는 크게 3가지 유형이 고려되었다. 가장 중요한 설립목적 및 기대효과로는 출연(연)의 목표지향적(mission-oriented) 연구에 파급지향적(diffusion-oriented) 메카니즘을 도입함으로써 출연(연)의 연구성과가 경제사회로 효과적으로 이전될 수 있도록 하기 위함이다. 단설대학원의 설립모델로서 첫째 유형은 각 출연(연)이 교육과정을 운영하는 개별대학원 모델이다. 이는 출연(연)의 연구기능과 교육기능을 현장에서 융합시켜 운영하는 것으로 설립이 비교적 용이하며 개별 출연(연)의 특수성을 살릴 수 있다. 출자형식으로 별도의 학교법인을 설립하는 방식과 내부규정으로 부설대학원을 설치운영하는 두 가지 방식 있을 수 있다. 둘째 유형은 출연(연) 연합대학원 모델이다. 출연(연)들이 연합으로 하나의 학교 법인을 설립하고 여기에 각 출연(연)들이 공동운영자로서 참여하는 방식이다 이때 연합대학원은 일종의 Virtual University 형태를 취하며 모든 교육은 참여 출연(연)에서 이루어지는 형태이다. 세 번째는 대학과 출연(연)이 연계대학원을 운영하는 모델이다. 대학의 대학원을 개방하여 출연(연) 측과 공동으로 운영하는 것으로 이는 별도의 학교법인 설립이 필요없다. 본 연구에서는 KAIST와의 연계대학원을 고찰하였다. 본 연구에서는 이들 각각의 모델에 대한 의미와 장점, 단점을 비교분석하고, 각 모델로 설립시의 법적 고려사항, 그리고 학사운영체제 등에 관해 구체적으로 고려하였다. 추가적으로 단설대학원의 설립에 관한 그간의 반대 및 우려사항에 대한 검토도 첨부하였다.한다. 선진국의 경우에도 우선 지원분야에 대한 연구비 배분은 5-10%사이이다. (ⅴ) 성과관리를 통한 지원효과의 극대화 : 기초과학의 지원에 있어서 그 성과를 특정한다는 것은 쉬운 일이 아니지만 연구비 지원효과를 극대화하기 위해서는 프로그램 평가를 통해 성과관리를 하여야 한다. (ⅵ) 효율적인 혁신시스템의 구축 : 혁신시스템의 효율적인 운영이 매우 중요하다. 이를 위해서는 첫째, 연구부문과 산업부문을 연결시킬 수 있고, 새로운 분야를 담아낼 수 있는 유연한 분야분류체계를 정립하여야 하고, 둘째 연구결과의 효율적인 활용이 이루어져야 하며, 셋째 연구지원기관간 연계시스템의 구축을 구축하여야 한다.s of rats with alveolar organism. (omitted)없었다 (P＞0.05). 6. 분만 2 개월 전에 Se과 Vit. E를 투여한 한우 종빈우로부터 태어난 송아지의 혈중 Vit. E 농도에 미치는 효과를 검토한 결과, 투여구가 대조구보다 다소 높은 농도를 나타냈으나 처리구간 커다란 차이는 없었다 (P＞0.05).ine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as compared to that of control. In case of R-20458, the increasing rates were varied at the

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• 제33권5호
• /
• pp.353-361
• /
• 2015

The area of red tides occurences, which brings enormous damages every year, have been expanded to the coastal waters across the nation. Regarding to this trend, the development of red tide detection technology by using the GOCI (Geostationary Ocean Color Imager) of COMS lauched in 2010 has been drawn attentions of researchers. This study purposed on analyzing the frequency and density of red tides occurence by using the GOCI for detecting the southern sea, whereas targeted area. The observation has brought over the last three years (2012, 2013, and 2014) before the analysis was conducted. Followingly, the study could be resulted in extracting and revealing the hot spots of the red tides from two of analysis in the overlay and density. The distribution patterns of red tide occurrences according to those observed years has been shown in irregular characteristics and various changes. However, the analysis of hot spots, based on the frequency of the red tide occurrence, has revealed that the frequency of red tide occurences is continuously increased in the specific sea area. Therefore, it is concluded in that the continuous monitoring can contribute to predict accurate movements of red tides, so as establish systematic plans for preventing disasters.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• 제31권5호
• /
• pp.343-353
• /
• 2013

Recently, the landscape change by development has become more important and it's been stipulated that environmental effects evaluation must include LIA which reflects the said issue. Even though the selection of viewpoints which have the biggest impact on LIA result is stipulated in accordance with related rules, the criteria are inconsistent. Therefore, LIA experts' or project developers' subjective opinions have been very influential. In this case, wrong viewpoints which do not meet the selection criteria could be selected based on a discretionary interpretation on them, which could in turn substantially reduce an accuracy and reliability of the LIA results. Therefore, this research suggested the reverse-viewshed frequency technique as method that can be verified accuracy and reliability of viewpoints. And it has comparatively analyzed effective viewpoints using reverse-viewshed frequency analysis on viewpoints which were selected for LIA. As a result, the average validity was just 58% of total viewpoints used in construction sites. And the validity of viewpoints decreased as viewshed frequency increased. Based on results above, it was able to verify that the unreasonable points of a substantial proportion have been used as viewpoints in LIA process.

• The Journal of the Korea Contents Association
• /
• 제8권3호
• /
• pp.86-96
• /
• 2008

General development basis of letter system is recognized by formative value in terms of its function and structure. principle of clustered writing is the most significant feature of Hangeul typography as considered that it is based on function and formativeness. Thus, not only by changes with its form but also by its characteristic syllable combination, space structure is made as consonants and vowels are combined in single letter, then the combination develop into word, sentence, paragraph to make second, third space structure character. This character has significant impact on readability that is core function of typography. With this property, space structure character is regarded as very important component of Hangeul typography. First, space structure character of Hangeul typography is reviewed by relating it to visual perception of gestalt psychology and compared square-framed letter and framed latter By applying square-framed letter and framed latter in same sentence, legibility and readability were studied. Researcher has found that space structure character of Hangeul typography has significant impact on its function, and in terms of future design, it is very critical not only for design but also for communication environment as space structure formativeness of Hangeul typography interact with communication that is basic concept.

• The Journal of the Korea Contents Association
• /
• 제14권2호
• /
• pp.181-191
• /
• 2014

In the past, making IR photography needed somewhat complicated process, so its application fields were limited. However, it has become easy to make IR photography with advanced digital technology, so it is expected that the fields of IR photography and existing limit due to difficult making process will be expanded. Therefore, in this study, it is decided that the need of IR standard chart which allows us to manage exposure and tone of IR photography for scientific purpose will increase. Two methods were used to make IR standard chart. First method is to use aluminum. When aluminum has oxide coating through anodic oxidation, it has high durability, corrosion resistance and heat resistance. Also, IR reflectance of aluminum can be controlled in some degree depending on the thickness of oxide coating. Second method is to use pigments. Yellow 10P150 pigment is used for the brightest patch. This pigment is appropriate in this study due to high heat resistance and IR reflectance. Carbon black is used for the darkest patch. Carbon black absorbs much IR, and its color is not faded by any source of light. IR reflectance is adjusted elaborately by mixing two pigments. Finally, 6 patches are selected with consideration for actual IR reflectance of patches. As a result, IR reflectance of random subjects can be known approximately and IR photographs can have appropriate contrast with the IR standard chart.