• Journal of Korean Elementary Science Education
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• v.20 no.1
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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.

• Korean Journal of Oriental Medicine
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• v.16 no.3
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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.

• Microbiology and Biotechnology Letters
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• v.33 no.1
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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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• v.27 no.1
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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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• v.38 no.2
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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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.

• Journal of the Korean Society for Library and Information Science
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• v.54 no.2
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• pp.105-125
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• 2020

This study attempts to identify the influence factors on the numbers of visitors and reference room users of public libraries through log-log multiple regression models, using the Korean National Libraries Statistical Data 2018. The fact found is summarized as follows; Even though books collection and seating capacities might be the most important factors in attraction of visitors and reference room users to public libraries in the past when the storage and propagation of knowledge and information was the top function of public libraries, very various and compound factors such as cultural or lifetime education programs, library operation, and user activities have an effect on inducing people to visit and use public libraries at present. This means that these days, public libraries are being transformed into some kinds of comprehensive cultural center where software elements such as cultural programs, user education, events, budget, membership, opening days, building style and age, and group activities rather than hardware elements such as books, literature material, and facilities constitute their essential parts in connection with visitor and user induction.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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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.

• Geotechnical Engineering
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• v.10 no.3
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• pp.79-96
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• 1994

A tunnel design expert system entitled NESTED is developed using the artificial neural network. The expert system includes three neural network computer models designed for the stability assessment of underground openings and the estimation of correlation between the RMR and Q systems. The expert system consists of the three models and the computerized rock mass classification programs that could be driven under the same user interface. As the structure of the neural network, a multi -layer neural network which adopts an or ror back-propagation learning algorithm is used. To set up its knowledge base from the prior case histories, an engineering database which can control the incomplete and erroneous information by learning process is developed. A series of experiments comparing the results of the neural network with the actual field observations have demonstrated the inferring capabilities of the neural network to identify the possible failure modes and the support timing. The neural network expert system thus complements the incomplete geological data and provides suitable support recommendations for preliminary design of tunnels in rock masses.

• Steel and Composite Structures
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• v.27 no.2
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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.