• 한국초등과학교육학회지:초등과학교육
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• 제20권1호
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• pp.107-122
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• 2001

The Purpose of this study is to find the effects of the portfolio assessment on elementary students' scientific knowledge, inquiry process skill, scientific attitudes in the teaching of science. And finally the parents' response to the portfolio assessment is also investigated. In order to reach the goal of this study, the investigator developed the evaluation instrument such as an experimental report and a cumulative observation sheet for the 4th-grade Unit-1 'Light Propagation' and Unit-3 'Separating Mixtures', and then these were administered to 42 4th-grade elementary students in Inchon. Based upon the findings and within the limitations of this study, several conclusions can be drawn regarding the problems investigated. First, as the portfolio assessment offers enough information about individual student's performance, it has a highly positive effect on evaluating the students' scientific knowledges. It can also make possible to grasp the several aspects of the student's progress. Second, the portfolio assessment can be implemented without giving students any psychological pressure from testing itself. Therefore, the portfolio assessment is an effective means of appraising inquiry process skills. Third, the portfolio assessment is effective to evaluate the students' attitude toward science by means of individual records which include such aspects that is hardly found by the teacher who teaches science in the class. Fourth, as most parents showed a positive response to this portfolio assessment, it is considered to be effective method of appraising the result of teaching science at elementary school. Accordingly, this study demonstrated that the portfolio assessment is an effective method that can assess students' scientific knowledges, inquiry process skills, and scientific attitudes gained from science teaching-learning. Therefore, it is necessary to implement the portfolio assessment to other grade students as well in the following study where teacher may give more encouragements and suggestions to sti dents for the better learning motives. Also teachers should suggest more definite evaluation criteria to students so that they may improve the students' self and peer evaluation skills.

• 한국한의학연구원논문집
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• 제16권3호
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• pp.77-84
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• 2010

In this study, YakMyeongSi were considered to define relations of Tradional Korean Medicine(TKM) and literature. In the introduction, present related studies were searched to clarify YakMyeongSi are completely different from medical property songs(YakSeongGa). Related data about YakMyeongSi and YakSeongGa were extracted for the initial findings. In chapter 2, medical name verse was defined as 'a type of free verses with one or more medical names in each verse to be interpreted ordinarily' based on records and examples of YakMyeongSi. In China, it originated from "Book of Odes" and "Songs of Chu", and it was most popular in the Song-China. Medical names actually referred to medical names in the early forms of the Warring States Period, but the complete form of YakMyeongSi started to appear in the Tang-China. In chapter 3, 34 YakMyeongSi and 5 related data were suggested in tables as the present conditions of Korean YakMyeongSi. With actual examples, better comprehension of YakMyeongSi were intended. Also, the fact that Korean YakMyeongSi were completed in forms at the end of Goryeo and beginning of Joseon dynasty. The motivations of writing YakMyeongSi were also studied. Medical names were put into verses because they well expressed landscapes and emotions. Propagation of medical knowledge was the basis of YakMyeongSi. There are limits in defining the relations of TKM and literature with some YakMyeongSi. More studies must be carried out on YakMyeongSi in various records with details and interests. Also, study to define general relations of TKM and literature must be carried out together by examining TKM in literary forms such as medical introductions or medical property songs and literature pieces that expressed principles and materials of TKM.

• 한국미생물·생명공학회지
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• 제33권1호
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• pp.1-8
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• 2005

Since Anton van Leeuwen­hoek first observed a surface-associated multicellular structure of bacterial cells in the 17th century, it has been shown to exhibit an ability to form a biofilm by numerous bacterial species. The biofilm formation is composed of distinct developmental stages, which include an attachment/adhesion of a single cell, a proliferation toward monolayered coverage, a propagation to aggregated microcolony, a maturation to 3-dimensional structure, and subsequently a local degradation. Investigation to identify the essential factors for bacterial biofilm formation has been performed via classical genetic approaches as well as recently developed technologies. The initial stage requires bacterial motility provided by a flagellum, and outermembrane components for surface signal interaction. Type IV-pilus and autoaggregation factors, e.g., type I-fimbriae or Ag43, are necessary to reach the stages of monolayer and micro colony. The mature biofilm is equipped with extracellular polymeric matrix and internal water-filled channels. This complex architecture can be achieved by differential expressions of several hundred genes, among which the most studied are the genes encoding exopolysaccharide biosyntheses and quorum-sensing regulatory components. The status of our knowledge for the biofilms found in humans and natural ecosystems is discussed in this minireview.

• Ocean and Polar Research
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• 제27권1호
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• pp.109-113
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• 2005

To facilitate estimation of the barbel size of a striped sea catfish, Plotosus lineatus Thumberg total length (TL) and head length (HL) against body weight (BW), HL against TL, and 1st maxillary barbel $(MxBL_1)$, 2nd maxillary barbel $(MxBL_2)$, 1st mandibular barbel $(MnBL_1)$ and 2nd mandibular barbel $(MnBL_2)$ against HL were regressed. The relationship of TL and HL for BW were described by the equation $TL=50.9373BW^{0.3072}\;(r^2=0.9898)$ and $HL=11.2938BW^{0.3144}(r^2=0.9572)$, respectively. The relationship of HL for TL was described by the linear equation $HL=0.1982TL+2.1996(r^2=0.9568)$. The relationship of each barbel for HL described by the equation of $HxBL_1=0.04420HL+0.3105(r^2=0.9615),\;MxBL_2=0.4592HL+0.5321(r^2=0.9519), MnBL_l=0.4057HL+1.9824 (r^2=0.9465)\;and\;MnBL_2=0.4355HL+1.8010(r^2=0.9429)$. Knowledge of the relative growth patterns about each barbel of this species is important for the propagation of seed as stock for large-scale striped sea catfish culture.

• Nuclear Engineering and Technology
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• 제38권2호
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• pp.147-154
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• 2006

Thermal fatigue of the coolant circuits of PWR plants is a major issue for nuclear safety. The problem is especially accute in mixing zones, like T-junctions, where large differences in water temperature between the two inlets and high levels of turbulence can lead to large temperature fluctuations at the wall. Until recently, studies on the matter had been tackled at EDF using steady methods: the fluid flow was solved with a CFD code using an averaged turbulence model, which led to the knowledge of the mean temperature and temperature variance at each point of the wall. But, being based on averaged quantities, this method could not reproduce the unsteady and 3D effects of the problem, like phase lag in temperature oscillations between two points, which can generate important stresses. Benefiting from advances in computer power and turbulence modelling, a new methodology is now applied, that allows to take these effects into account. The CFD tool Code_Saturne, developped at EDF, is used to solve the fluid flow using an unsteady L.E.S. approach. It is coupled with the thermal code Syrthes, which propagates the temperature fluctuations into the wall thickness. The instantaneous temperature field inside the wall can then be extracted and used for structure mechanics computations (mainly with EDF thermomechanics tool Code_Aster). The purpose of this paper is to present the application of this methodology to the simulation of a straight T-junction mock-up, similar to the Residual Heat Remover (RHR) junction found in N4 type PWR nuclear plants, and designed to study thermal striping and cracks propagation. The results are generally in good agreement with the measurements; yet, in certain areas of the flow, progress is still needed in L.E.S. modelling and in the treatment of instantaneous heat transfer at the wall.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.557-561
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• 2014

In this work, Altair Engineering's vibroacoustic modeling approach is used to simulate the acoustic signature of a simplified automobile in a wind tunnel. The modeling approach relies on a two step procedure involving simulation and extraction of acoustic sources using a high fidelity Computational Fluid Dynamics (CFD) simulation followed by propagation of the acoustic energy within the structure and passenger compartment using a structural dynamics solver. The tools necessary to complete this process are contained within Altair's HyperWorks CAE software suite. The CFD simulations are performed using AcuSolve and the structural simulations are performed using OptiStruct. This vibroacoustics simulation methodology relies on calculation of the acoustic sources from the flow solution computed by AcuSolve. The sources are based on Lighthill's analogy and are sampled directly on the acoustic mesh. Once the acoustic sources have been computed, they are transformed into the frequency domain using a Fast Fourier Transform (FFT) with advanced sampling and are subsequently used in the structural acoustics model. Although this approach does require the CFD solver to have knowledge of the acoustic simulation domain a priori, it avoids modeling errors introduced by evaluation of the acoustic source terms using dissimilar meshes and numerical methods. The aforementioned modeling approach is demonstrated on the Hyundai Simplified Model (HSM) geometry in this work. This geometry contains flow features that are representative of the dominant noise sources in a typical automobile design; namely vortex shedding from the passenger compartment A-pillar and bluff body shedding from the side view mirrors. The geometry also contains a thick poroelastic material on the interior that acts to reduce the acoustic noise. This material is modeled using a Biot material formulation during the structural acoustic simulation. Successful prediction of the acoustic noise within the HSM geometry serves to validate the vibroacoustic modeling approach for automotive applications.

• 한국문헌정보학회지
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• 제54권2호
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• pp.105-125
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• 2020

본 연구는 2018년 전국도서관통계를 활용하여 공공도서관 방문자수 및 자료실이용자수에 미치는 영향요인을 log-log 중회귀모형으로 분석했다. 분석 결과를 요약하면 다음과 같다. 과거, '지식과 정보의 저장 및 전파'가 공공도서관의 주된 기능이던 시대에 이용자 유치에 가장 중요했을 것으로 생각되는 장서수나 좌석수 등의 요소를 넘어 현재는 문화 혹은 평생교육 프로그램, 도서관 운영, 이용자활동 등의 차원에서 매우 다양하고 복합적인 요소들이 방문자 및 자료실이용자 유인에 영향을 주고 있다. 이는 이제 도서관은 책이나 자료, 시설 등의 하드웨어적 요소보다는 문화 프로그램, 이용자 교육, 행사, 예산, 회원수, 개관시간, 건물의 스타일과 노후도, 동아리활동 등의 소프트웨어적 요소에 이끌려 찾아가는 종합문화센터가 되고 있다는 것을 뜻한다.

• 한국농공학회논문집
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• 제55권6호
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• pp.101-112
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• 2013

Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) offers opportunities to make advances in many research areas including hydrology by providing near-global scale elevation measurements at a uniform resolution. Its wide coverage and complimentary online access especially benefits researchers requiring topographic information of hard-to-access areas. However, SRTM DEM also contains inherent errors, which are subject to propagation with its manipulation into analysis outputs. Sensitivity of hydrologic analysis to the errors has not been fully understood yet. This study investigated their impact on estimation of hydrologic derivatives such as slope, stream network, and watershed boundary using Monte Carlo simulation and spatial moving average techniques. Different amount of the errors and their spatial auto-correlation structure were considered in the study. Two sub-watersheds of Geum and Deadong River areas located in South and North Korea, respectively, were selected as the study areas. The results demonstrated that the spatial presentations of stream networks and watershed boundaries and their length and area estimations could be greatly affected by the SRTM DEM errors, in particular relatively flat areas. In the Deadong River area, artifacts of the SRTM DEM created sinks even after the filling process and then closed drainage basin and short stream lines, which are not the case in the reality. These findings provided an evidence that SRTM DEM alone may not enough to accurately figure out the hydrologic feature of a watershed, suggesting need of local knowledge and complementary data.

• 한국지반공학회지:지반
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• 제10권3호
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• pp.79-96
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• 1994

인공신경회로망을 이용하여 터널굴착설계를 위한 전문가 시스템 NESTED를 개발하였다. 이를 위하여 지하 암반의 안정성을 평가할 수 있는 신경회로망 모델과 대표적인 암반분류법인 RMR과 Q 시스템 사이의 상관관계를 결정할 수 있는 신경회로망 모델을 사용하였다. 또한 사용된 모델과 전산화된 암반분류법 프로그램이 동일한 사용자 환경을 통해 운용될 수 있도록 통합 시스템을 구성하였다. NESTED에 사용된 신경회로망의 구조는 역전파 학습 알고리즘을 채용한 다층 역전파 신경 회로망이다. 전문가 시스템에 필요한 지식기반을 구축하기 위해 이전의 현장 시공사례로 학습과정을 수행함으로써 불완전하거나 오류가 포함된 정보를 처리할 수 있는 공학 데이터베이스를 개발하였다. 일련의 실험을 통해 전문가 시스템을 현장사례에 적용해보고 여기서 출력된 결과를 문헌에 보고된 자료와 비교하였다. 이 결과 암반의 파괴거동을 추정하고 이에 따른 보강시기의 변화를 정확히 예측하는 신경회로망의 추론능력을 확인할 수 있었다. 이처럼 본 연구를 통해 개발된 신경회로망 전문가 시스템을 암반터널에 적용할 경우 부족한 지질자료에 대해 합리적인 기준을 제공하고 터널의 예비설계에 필요한 보강설계를 제시할 수 있었다.

• Steel and Composite Structures
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• 제27권2호
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• pp.201-216
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• 2018

In this paper, three-dimensional (3D) elasticity theory in conjunction with nonlocal strain gradient theory (NSGT) is developed for mechanical analysis of anisotropic nanoparticles. The present model incorporates two scale coefficients to examine the mechanical characteristics much accurately. All the elastic constants are considered and assumed to be the functions of (r, ${\theta}$, ${\varphi}$), so all kind of anisotropic structures can be modeled. Moreover, all types of functionally graded spherical structures can be investigated. To justify our model, our results for the radial vibration of spherical nanoparticles are compared with experimental results available in the literature and great agreement is achieved. Next, several examples of the radial vibration and wave propagation in spherical nanoparticles including nonlocal strain gradient parameters are presented for more than 10 different anisotropic nanoparticles. From the best knowledge of authors, it is the first time that 3D elasticity theory and NSGT are used together with no approximation to derive the governing equations in the spherical coordinate. Moreover, up to now, the NSGT has not been used for spherical anisotropic nanoparticles. It is also the first time that all the 36 elastic constants as functions of (r, ${\theta}$, ${\varphi}$) are considered for anisotropic and functionally graded nanostructures including size effects. According to the lack of any common approximations in the displacement field or in elastic constant, present theory can be assumed as a benchmark for future works.