• 복식문화연구
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• 제30권5호
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• pp.717-731
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• 2022

The purpose of this study is to suggest effective online pedagogical strategies for a fashion design CAD course to enhance student learning and satisfaction. The study investigated student experience of online learning and compared online learning with a face-to-face learning experience. Student concentration, participation, perceptions of effectiveness of teaching, utilization of learning materials, and satisfaction were analyzed using a 5-point Likert scale. Advantages and disadvantages of online learning as well as advantages of face-to-face learning were also analyzed both quantitatively and qualitatively. Student concentration, participation, and perception of effectiveness of teaching were greater for face-to-face learning with significantly higher concentration on individual practice. Students utilized video recording of synchronous online lectures more actively than PDF lecture notes. The advantages of face-to-face learning were plentiful communication and feedback and easy questioning process as well as high levels of understanding and concentration. Meanwhile, major disadvantages of online learning were the speed of the lecture, lower levels of understanding and concentration, limited peer interaction, and technical problems. Major advantages of online learning were flexibility and convenience, repetitive learning through videos, and instant communication and feedback. Students preferred a blended learning approach for the fashion design CAD course. For effective online learning, it is suggested that instructors frequently question and check student practice through screen share in a private online meeting room and engage activities that are demanding of student interaction. The video recording of synchronous online lectures is also suggested as a supplemental learning material for repetitive learning.

• Structural Engineering and Mechanics
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• 제63권3호
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• pp.269-280
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• 2017

One major concern that has occupied the mind of the designers is a structural failure as result of stress concentration in the geometrical discontinuities. Understanding the effective parameters contribute to stress concentration and proper selection of these parameters enables the designer get to a reliable design. In the analysis of perforated isotropic and orthotropic plates, the effective parameters on stress distribution around holes include load angle, curvature radius of the corner of the hole, hole orientation and fiber angle for orthotropic materials. This present paper tries to examine the possible effects of these parameters on stress analysis of infinite perforated plates with central quasi-square hole applying grey wolf optimizer (GWO) inspired by the particular leadership hierarchy and hunting behavior of grey wolves in nature, and also the present study tries to introduce general optimum parameters in order to achieve the minimum amount of stress concentration around this type of hole on isotropic and orthotropic plates. The advantages of grey wolf optimizer are stout, flexible, simple, and easy to be enforced. The used analytical solution is the expansion of Lekhnitskii's solution method. Lekhnitskii applied this method for the stress analysis of anisotropic plates containing circular and elliptical holes. Finite element numerical solution is employed to examine the results of present analytical solution. Results represent that by selecting the aforementioned parameters properly, fewer amounts of stress could be achieved around the hole leading to an increase in load-bearing capacity of the structure.

• 한국임상수의학회지
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• 제18권1호
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• pp.48-54
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• 2001

The effects of PMSG and/or prostaglandin analogue, cloprostenol, on the prevention of implantation, termination of pregnancy, concentration of plasma progesterone, and Na and K contents of the plasma and uterine fluid were studied in pregnant rats. PMSG 50 or 100 IU concomitant with cloprostenol 90 or 180 mg were administered once on day 3 or 9 of gestation. Rats were autopsied on days 8, 10 or 21 gestation. A single administration of PMSG resulted in increasing the number of corpora lutea, preventing implantation and terminating pregnancy. A single administration of cloprostenol had no effect on the prevention of implantation and termination of pregnancy but was able to induce the termination of pregnancy administering at large doses on day 9. A single administration of PMSG concomitant with cloprostenol ws found to be very increased the number of corpora lutea and to be 100% effective in preventing implantation and to be nearly 100% effective in terminating pregnancy. It is uncommon that a single dose of PMSG 50 IU concomitant with cloprostenol 90 or 180 mg on day 9 was able to maintain the pregnancy at very low rates of 0.3∼5.3%. Concentration of plasma progesterone and Na and K contents of the plasma and uterine fluid were increased or decreased administering PMSG and/or cloprostenol, but had no effect on preventing implantation and terminating pregnancy.

• Journal of Microbiology and Biotechnology
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• 제12권4호
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• pp.706-709
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• 2002

Bacterial bioluminescence has been known to be a highly valuable reporter system for its potential application as an effective and simple environmental monitoring method for toxic compounds. In this short report, we constructed a streptomycetes-Escherichia coli shuttle vector-containing bioluminescence system and evaluated its potential application for toxic compounds monitoring. The luxAB biolurninescence genes from Vibrio harveyi were cloned into a streptornycetes-E. coli shuttle vector (named pESK004) and functionally expressed in Streptomyces lividans. The recombinant S. lividans containing pESK004 exhibited an optimal biolurninescence at the optical density ($OD_{600\;nm}$) of 0.4-0.5 and aldehyde concentration of 0.005%. When the recombinant bioluminescence streptomycetes was exposed to a toxic compound such as heavy metals, chlorinated phenols, or pesticides, the bioluminescence was decreased proportionally to the concentration of toxic compound in the assay mixture. The $EC_{50}$ (effective concentration to decrease 50% of the bioluminescence prior to exposure) values in the recombinant biolurninescence streptomycetes for mercury, 2,4-dichlorophenol, and malathion were measured at 2.2 ppm, 144.0 ppm, and 82.4 ppm, respectively. The degree of sensitivity and specificity pattern toward these toxic compounds characterized in this recombinant bioluminescence streptomycetes were unique when compared with previously reported bacterial bioluminescence systems, and this revealed that a recombinant bioluminescence streptomycetes might provide an alternative or complementary system for potential environmental monitoring.

• 대한기계학회논문집A
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• 제27권5호
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• pp.724-733
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• 2003

Fatigue design rules for welds in the ASME Boiler and Pressure Vessels Code are based on the use of Fatigue Strength Reduction Factors(FSRF) against a code specified fatigue design curve generated from smooth base metal specimens without the presence of welds. Similarly, stress intensification factors that are used in the ASME B3l.1 Piping Code are based on component S-N curves with a reference fatigue strength based on straight pipe girth welds. But the determination of either the FSRF or stress intensification factor requires extensive fatigue testing to take into account the stress concentration effects associated with various types of component geometry, weld configuration and loading conditions. As the fatigue behavior of welded joints is being better understood, it has been generally accepted that the difference in fatigue lives from one type of weld to another is dominated by the difference in stress concentration. However, general finite element procedures are currently not available for effective determination of such stress concentration effects. In this paper, a mesh-insensitive structural stress method is used to re-evaluate the S-N test data, and then more effective method is proposed for pressure vessel and piping fatigue design.

• 한국항행학회논문지
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• 제12권3호
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• pp.201-207
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• 2008

대용량 WDM 전송 시스템의 구현을 위해 중간에 광 위상 공액기 (optical phase conjugator)를 갖는 광섬유에서 축적된 분산량을 precompensation과 postcompensation으로 조절하는 분산 제어 (DM; dispersion management) 전송 링크의 설계 기준을 제시하였다. 본 논문에서 살펴본 DM 구조는 precompensation과 postcompensation가 이루어지는 위치에 따라 bi-end 형태와 concentration 형태의 두 가지이다. 전송 링크 설계 파라미터인 송신기부터 OPC까지의 구간과 OPC부터 수신기까지의 유효 잉여 분산 범위는 OPC에 대해서만 대칭되어 있으면 precompensation과 postcompensation을 수행하는 분산 보상 광섬유(DCF; dispersion compensating fiber)의 위치에 크게 의존하지 않는다는 것을 확인하였다.

• 환경영향평가
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• 제10권2호
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• pp.135-145
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• 2001

This study was conducted to investigate the practical using of Geographic Information System(GIS) technology which are computer-based systems that are used to store and manipulate geographic information on the air pollution control and management in the macro city. For this study 130 samples were corrected by passive sampler in Seoul (25 distincts) distributed by TM-coordinate during November in 1997 to January 1998, and analysed by GC/MSD for 16 VOCs e.g., toluene, benzene and display using Arc/view GIS(version 3.2, ESRI Inc, U.S.A) for windows. The most VOCs concentration distribution in November, 1997 was higher than that of January, 1998 except benzene and 1,1,2-trichroloethan, bromobenzene. And products of the distribution of VOCs concentration display using GIS technology was effective as well as other display methods(e.g., contouring method, pie or column chart, graduated symbols), especially in mapping and symbolization capabilities for spatial pollutant status evaluation were very effective than other display methods.

• 한국대기환경학회지
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• 제14권6호
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• pp.607-620
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• 1998

The influence of transportation on air quality has been elevating in urban area. Air pollutants from automobiles cause primary and secondary air pollution, and need to be tightly controlled. In this study, the effect of automobile air pollutants on highway vicinity area was evaluated by the comparison of field measurement. and target was for modeling using CALINE3, NO2 was the target for this work. It was found that the concentration predicted by CALINE3 is overestimated at low wind speed and input data of wind speed requires correction. Based on the measured data, the wind speed was modified by effective wind speed equation [Ue=U+0.24·EXP(-pxU)], and there after the accuracy of CALINE3 calculation was improved neighborhood area of highway. It was also observed that weather conditions and traffic volume affect the concentration of air pollution. Finally, the NO2 effect of automobile air pollutants on the vicinity area of highway proved to be up to 400∼600m from the highway.

• Journal of information and communication convergence engineering
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• 제7권4호
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• pp.576-579
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• 2009

Anti-HIV-1 activities for the extracts (buthanol, hexane, chloroform, and water) of medicinal plants widely used in the folk medicine were evaluated for screening of anti-AIDS agents. The activities of the extracts to inhibit HIV-1 replication were also analyzed. The 50% effective concentration (EC50) of inhibition activity of the p24 production for chloroform extract of Saphora flavescens, chloroform extract of Herba ephedrae, and hexane extract of Pachyma hoelen Rumph showed 5.8, 29.9, and 37.3 2g/ml, respectively, as good activities. Hexane extract of Sophora flavescens, buthanol extract of Tulipa edulis, hexane extracts of Tulipa edulis, Herba ephedra, and Pachyma hoelen Rumph in the 50% cytotoxic concentration ($CC_{50}$) in inhibition activities of recombinant HIV-1 RT showed 12.9, 19.5, 11.6, 12.0, and 36.8 % at concentration of 200 ${\mu}g$/ml, respectively, as good activities. From these results, chloroform extract of Saphora flavescens, chloroform extract of Herba ephedrae, and hexane extract of Pachyma hoelen Rumph were very effective against HIV-1 among all extracts tested. Therefore, we expect these plants will be a useful for anti- HIV-1 therapeutics in future.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4316-4320
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• 2011

The effects of various hydroxide compounds on base stacking (BS) were investigated for pre-concentration of DNA molecules in capillary electrophoresis (CE). In BS, hydroxide ions ($OH^-$) were electrokinetically introduced after DNA sample injection. A neutralization reaction occurred between the $OH^-$ and $Tris^+$ of the running buffer, which resulted in a zone of lower conductivity. Within the low conductivity zone of the high electric field, the DNA molecules moved more rapidly and were concentrated in front of the low conductivity zone. At the same BS conditions of CE, the enhanced sensitivity of the DNA samples was dependent on the kind of multivalent cations in the hydroxide compounds. Except for LiOH, the hydroxide compounds with monovalent cations showed more effective BS than those with divalent cations because of solubility, ionic strength and electronegativity. The order of hydroxide compounds that enhance the detection sensitivity of DNA molecules was as follows: NaOH > $NH_4OH$ > KOH > $Ba(OH)_2$ > $Sr(OH)_2$ > LiOH > $Ca(OH)_2$ > $Mg(OH)_2$. $NH_4OH$, KOH and $Ba(OH)_2$ proved to be efficient hydroxide compounds to use as effective BS reagents in CE instead of NaOH.