• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.1
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• pp.64-75
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• 2009

The shipbuilder's requirement for a higher power output rating has led to the development of a super large two stroke low speed diesel engines. Usually a large-sized bore engine ranging from $8{\sim}14$ cylinders, this engine group is capable of delivering power output of more than 100,000 bhp at maximum continuous rating(mcr). Other positive aspects of this engine type include higher thermal efficiency, reliability, durability and mobility. This plays a vital role in meeting the propulsion requirement of vessels, specifically for large container ships, of which speed is a primary concern to become more competitive. Consequently, this also resulted in the modification of engine parameters and new component designs to meet the consequential higher mean effective pressure and higher maximum combustion pressure. Even though the fundamental excitation mechanisms unchanged, torsional vibration stresses in the propulsion shafting are subsequently perceived to be higher. As such, one important viewpoint in the initial engine design is the resulting vibration characteristic expected to prevail on the propulsion shafting system(PSS). This paper investigated the torsional vibration characteristics of these super large engines. For the two node torsional vibration with a nodal point on the crankshaft, a tuning damper is necessary to reduce the torsional stresses on the crankshaft. Hence, the tuning torsional vibration damper design and compatibility to the shafting system was similarly reviewed and analyzed.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1342-1347
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• 2007

최근 수자원 분야에서 GIS의 활용은 유역의 수리, 수문분석을 위한 모형의 입력자료 생성 및 모의 결과를 가시화, 이에 따른 유역관리 시스템의 구축 등 폭넓게 활용되고 있다. 또한 국가지리정보시스템에 조사를 통해서 수치지형도 및 주제도를 구축, 구축된 자료의 표준화를 실시하고 있는 실정이다. 그러나 수자원 분야에서 GIS를 활용하기 위한 기술은 주로 선진국을 중심으로 발전하여 왔기 때문에 우리의 실정에 맞지 않아 활용측면에 있어 신뢰할 만한 결과를 얻지 못하고 있는 실정이다. 따라서 국내 상황을 고려하면서 수자원이라는 전문분야 적용에 적합한 GIS(HyGIS)를 개발하고 여기에 수리, 수문분석모형을 연계하여 국내 실무분야에 적용함에 있어 편의성과 실용성을 구비한 모형개발이 이루어져야 한다. 따라서 본 연구에서는 국내 소프트웨어 GeoMania(HyGIS)에 의한 GIS 정보처리의 자동화를 기반으로 하여 실무에서 활용도가 높은 수문모형인 HEC-HMS 및 HEC-1과 수리모형인 HEC-RAS를 연계 및 통합하기 위해서 HyGIS에서 DLL형태로 제공되도록 하였다. HyGIS에서는 수문학적 DEM 분석 및 공간정보 생성, 선형참조가 가능한 하천 네트워크 생성, 유역 시설물 관리 등의 기능을 제공하며 COM(Component Object Model)을 기반으로 개발된 시스템으로 다른 소스로부터 개발된 컴포넌트를 연계하여 시스템의 기능 확장을 손쉽게 수행할 수 있도록 하였을 뿐만 아니라 공간 DB는 GeoMania의 고유 DB인 GSS를 이용한다. HyGIS-HMS는 HyGIS를 통한 국내 유역의 지리정보를 활용하여 HEC-HMS 뿐만 아니라 HEC-1을 추가하여 사용자의 기호와 편의에 따라 모형을 선택할 수 있도록 하였으며 HEC-1의 결과를 가시화하기 위해서 챠트 기능을 추가하였으며 매개변수를 자동으로 산정할 수 있도록 시스템을 구축하였다. HyGIS-RAS는 국내 하천유역에 대해서 기구축 되어있는 하천관리지리정보시스템(RIMGIS)자료를 직접 활용하도록 구성되어있고 자료를 활용하여 제내지와 제외지를 통합하여 TIN분석을 실시하여 범람 홍수해석에 활용할 수 있도록 하였다. 하천수리해석의 기능을 보강하기 위해 역산조도계수 산정모형, 상류-사류 천이류 구간에 대한 부등류 해석모형, 범람 홍수류에 대한 홍수위 산정모형, 하천수리계산시의 불확실도 해석모형 등의 새로운 기능을 추가하여 제시하였다. 모든 입출력자료는 프로젝트 단위별로 운영되어 data의 관리가 손쉽도록 하였으며 결과를 DB에 저장하여 다른 모형에서도 적용할 수 있도록 하였다. 그리고 HyGIS-HMS 및 HyGIS-RAS 모형에서 강우-유출-하도 수리해석-범람해석 등이 일괄되게 하나의 시스템 내에서 구현될 수 있도록 하였다. 따라서 HyGIS와 통합된 수리, 수문모형은 국내 하천 및 유역에 적합한 시스템으로서 향후 HydroInformatics 구현을 염두에 둔 특화된 국내 수자원 분야 소프트웨어의 개발에 기본 토대를 제공할 것으로 판단된다.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.268-273
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• 1996

Fundamental data for new type of product development from Lycii fructus was experimentally determined. The chemical composition, and Hunter value changes, optimum extraction, volatile components of extract under different extraction conditions and heat treatment were mainly studied. Results are summarized as follows. The proximate compositions of dried Lycii fructus were water 21.8%, total sugar 27.6%, reducing sugar 15.2%, crude protein 14.29%, crude fat 5.65%, crude fiber 7.48%, and ash 7.98% in percent stale, respectively. Extracted yield on the basic of solid extract was getting increased when more solvent was used for extraction. The most recommendable extraction was 1 to 10 part of sample to solvent ratio. When water was employed as extraction solvent, the highest amount of solid extract was obtained. Extract of Lycii fructus in terms of yields and color was most acceptable when raw sample was treated 8 minute roasting at $180^{\circ}C$ and 60 minute heating at $120^{\circ}C$, respectively. Major volatile components of fresh Lycii fructus were to hexadecanoic acid, methyl linoleate, benzyl alcohol, dimetane benzene by GC/MS. By the roasting of raw sample, the compounds of 2-methyl-2buthenal, 1,4-dimethyl benzene, and benzyl alcohol were reduced. Wheras, methyl thiopropanol, benzene acetaldehyde and ethyl linoleate were slightly increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.1
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• pp.80-87
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• 2009

Aiming at development of region specialized crop, this study was conducted to clarify variety and cultivation region dependent on antioxidative compounds in black soybean seeds. For this purpose two black soybean varieties (Ilpumgeomjeongkong and Cheongjakong) were cultivated in 3 different regions (Hwaseong in Gyeonggido, Naju in Jeollanamdo and Jinju in Gyeongsangnamdo) in 2004 and 2005, and harvested seeds were used for isoflavone, anthocyanin and tocopherol contents along with electron donating ability-based antioxidative activities measurements. 100 grain weight between two varieties were not significantly different, but Hwaseong district showed higher 100 grain weight compared to Jinju and Naju. Ilpumgeomjeongkong was higher total isoflavone content ($1,064.9{\mu}g/g$) compared to Cheongjakong ($801.3{\mu}g/g$) in 2004, whereas Cheongjakong showed higher in 2005 compared to Ilpumgeomjeongkong. The highest isoflavone content was obtained in Hwaseong district in 2004, whereas it is the reverse in 2005 that Jinju district showed the highest isoflavone content. In total anthocyanin content, Ilpumgeomjeongkong (7.22 mg/g) was higher than that of Cheongjakong (6.83 mg/g), and Jinju district showed the highest total anthocyanin content (9.16 mg/g) compared to Naju and Hwaseong cultivating districts in their three cultivating districts. Total tocopherol content showed no significant difference between two varieties, but Hwaseong ($217.2{\mu}g/g$) and Jinju ($216.3{\mu}g/g$) districts showed higher content compared to Naju ($189.7{\mu}g/g$) among three cultivating districts. In tocopherol content ratio, $\gamma$-tocopherol was the highest from 56.2% to 59.9%. In electron donating ability (EDA) between two cultivars, Ilpumgeomjeongkong was significantly higher than Cheongjakong, and Naju was the highest of 55.6% among three cultivating districts.

• Journal of KIISE:Software and Applications
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• v.29 no.4
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• pp.211-224
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• 2002

As system become larger and more complex, it is important to correctly analyze and specify user's requirements. Use case modeling is widely used in Object-Oriented Analysis and Design(OOAD) and Component-Based Development(CBD). It is useful to mitigate the complexity of the requirements analysis. However, use cases are difficult to be structured, to explicitly represent non-functional requirements, and to analyze what is affected by changes of use cases. To alleviate these problems, we propose scenario-based goal-oriented approach for use case modeling. The approach is to apply goal-oriented analysis method to use case model. Since goal-oriented analysis method is not systematic and heuristics is considerably involved, we adopted scenarios as the basis for the goal extraction. The proposed method is applied to City Bus Information Subsystem(CBIS) in Intelligent Transport Systems(ITS) domain. The proposed approach helps software engineer to analyze what is affected by use case's changes and represent non-functional requirements.

• Journal of Life Science
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• v.25 no.5
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• pp.607-614
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• 2015

Cancers are the largest cause of mortality and morbidity all over the world. Cordycepin, an adenosine analog, is a major functional component of the Cordyceps species, which has been widely used in traditional Oriental medicine. Over the last decade, this compound has been reported to possess many pharmacological properties, such as an ability to enhance immune function, as well as anti-inflammatory, antioxidant and anti-cancer effects. Recently, numerous studies have reported interesting properties of cordycepin as a chemopreventive agent as well. There is an accumulating body of experimental evidences suggesting that cordycepin impedes cancer progression by promoting apoptosis, inducing cell cycle arrest, modulating intracellular signaling pathways, and inhibiting invasion and metastasis of cancer cells. In many cancer cell lines, cordycepin inhibits growth and cell cycle progression by inducing arrest of the G2/M phase, resulting from the inhibition of retinoblastoma protein phosphorylation and induction of cyclin-dependent kinase inhibitors. To induce apoptosis, cordycepin activates the extrinsic and intrinsic pathways, which promotes reactive oxygen species generation and the downstream activation of kinase cascades. Cordycepin also can activate alternative pathways to cell death such autophagy. In addition, cordycepin can inhibit the pro-metastatic processes of cancer cell detachment, migration, and invasion through a variety of mechanisms, including the nuclear factor-kappa B and activated protein-1 signaling pathways. In this review, we summarized the variety of action mechanisms by which cordycepin may mediate chemopreventive effects on cancer and discussed the potential of this natural product as a promising therapeutic inhibitor of cancer development.

• Journal of Life Science
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• v.20 no.11
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• pp.1648-1655
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• 2010

The flavor extracts of Mideoduck muscle and its juices were concentrated by simultaneous distillation and extraction (SDE) and solid-phase microextraction (SPME) methods. Each component present in the extracts was identified with GC and GC-MS by the n-paraffin hydrocarbon retention index and standard MS library data system. By SDE, $371.3\;{\mu}g/g$ of hexanal, $80.1\;{\mu}g/g$ of 1-tridecanol, $72.1\;{\mu}g/g$ of (Z)-4,5-dimethylhex-2-en-4-ol with other alcohols, aldehydes and acids were present in the flavor extracts, with the alcohols having the highest composition and being the most important factor in Mideoduck muscle flavor. By SPME, 9 alcohols, 1 acid, 1 aldehyde, 1 hydrocarbon, 1 ester, 1 amine and 2 ketones were detected in the extracts, with alcohol such as 1-nonanol, 1-decanol and 1-tridecanol as the major components. In SPME, the muscle sample, consisting of $31.6\;{\mu}g/g$ of 1-nonanol, $20.3\;{\mu}g/g$ of (E)-2-butenedioic acid dibutylester, and $26.7\;{\mu}g/g$ of heptadecanoic acid made up the 62.1% of total flavor extracts of Mideoduck muscle. The results of the SPME methods were similar to the composition of the raw material flavor of the sample even at a low concentration.

• Transactions of the Korean hydrogen and new energy society
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• v.12 no.1
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• pp.29-38
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• 2001

The alloys $ZrMn_2Ni_x$ (x=0.0, 0.3, 0.6, 0.9 and 1.2) as the alloys of Zr-Mn-Ni three component system were prepared and their hydrogen-storage properties and their electrochemical properties were investigated. The C14 Laves phase formed in all the alloys $ZrMn_2Ni_x$. Among these alloys $ZrMn_2Ni_{0.6}$ was activated relatively easily(after about 11 charge-discharge cycles), and had the largest discharge capacity(max. 45mAh/g). For all the alloys Zr was dissolved most easily into the 6M KOH solution. More Mn and Ni were dissolved from the $ZrMn_2Ni_{0.6}$ alloy than from the other alloys. Due to the active charge and discharge of the $ZrMn_2Ni_{0.6}$ alloys, related to the easier activation and the larger discharge capacity, Zr, Mn and Ni in this alloy were considered to be dissolved more easily into the 6M KOH solution, compared with the other alloys.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.101-111
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• 2006

In case of drilled shafts installed by drilling through soft overburden onto a strong rock, the piles can be regarded as end-bearing elements and their working load is determined by the safe working stress on the pile shaft at the point of minimum cross-section or by code of practice requirements. Drilled shafts drilled down for some depth into weak or weathered rocks and terminated within these rocks act partly as friction and partly as end-bearing piles. The base resistance component can contribute significantly to the ultimate capacity of the pile. However, the shaft resistance is typically mobilized at considerably smaller pile movements than that of the base. In addition, the base response can be adversely affected by any debris that is left in the bottom of the socket. The reliability of base response therefore depends on the use of a construction and inspection technique which leaves the socket free of debris. This may be difficult and costly to achieve, particularly in deep sockets, which are often drilled under water or drilling slurry. As a consequence of these factors, shaft resistance generally dominates pile performance at working loads. The efforts to improve the prediction of drilled shaft pile performance are therefore primarily concerned with the complex mechanisms of shaft resistance development. In this study, the numerical analyses are carried out to investigate the behavior characteristics of side of rock socketed drilled shafts varying the loading condition at the pile head. The difference of behavior characteristics of side resistance is also evaluated with the effects of modelling of asperity.

• Journal of The Korean Association For Science Education
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• v.36 no.4
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• pp.629-641
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• 2016

Understanding of how teachers change instruction can help predict what kind of educational materials is supportive or appropriate. On the basis of this idea, we explored elementary teachers' PCK progression on specific topics of astronomy: planet size and distance in solar system. To identify the development of PCK over time, we utilized learning progression (LP) as a conceptual framework. The progression of teacher PCK can also be illustrated as the hypothetical pathway from novice to expert like LP. Eight 5th grade elementary teachers participated in this study. We observed participating teachers' astronomy classes with the same topic. In order to document topic-specific PCK of participating teachers, we developed an analytic protocol consisting of four categories: knowledge of curriculum, knowledge of teaching strategies, knowledge of assessment, and astronomical thinking practice. In addition, we monitored the changes in the four participating teachers' PCK for two years in order to validate the evidences of the PCK progression. Participating teachers in this study took some intervention by attending a four-week pre-meeting with the researchers to profile an adaptive instruction. Through this research, we profiled four and five different levels of PCK progressions in three knowledge components (curriculum, teaching strategies, student assessment) and one astronomical thinking practice (systems thinking), respectively. Participating teachers demonstrated various levels and pathways in each component of PCK. This study released the empirical evidences in fostering instructional scaffolding, which is appropriate to the level of PCK of science teachers on specific topic.