• Journal of the Korean Society of Earth Science Education
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• v.10 no.1
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• pp.38-49
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• 2017

The purpose of this study was to find out how pre-service teachers who have gone through training have thought about teaching practice. Specifically, I analyzed the relationship between college curriculum and teaching practice, and what they had felt in teaching practice. The study included 20 third grade students in teacher's college. The results of this study were as follows: First, it was found that the content knowledge and the pedagogical knowledge of the subjects taught at the university were helpful for the teaching practice. Second, they were thought that teaching practice would be helpful just to watch the class. And pre-service teachers felt that class demonstration was a necessary part of becoming a teacher. Third, pre-service teachers said that it is necessary to have a lecture in the university that can have opportunity for class demonstration for teaching practice. And also they wanted to open a lecture to learn various teaching techniques and the newest teaching methods. Fourth, pre-service teachers said that it is important to form relationships with students in order to complete the lessons through the teaching practice. And they said that they felt that the education scene was more powerful and harder than they thought. In addition, they said that through this exercise, it became a moment to feel the importance of thorough preparation and experience. In this way, teaching practice is an essential process for pre-service teachers to become teachers and it can be seen that they have many influences. Based on these results, it is necessary to review and revise the curriculum of the training colleges in relation to the teaching practice.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.199-210
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• 2011

The cables in cable-stayed bridges are under high stress and are very sensitive to vibration due to their small section areas compared with other members. Therefore, it is reasonable to evaluate the cable impact factor by taking into account the dynamic effect due to moving-vehicle motion. In this study, the cable impact factors were evaluated via moving-vehicle-load analysis, considering the design parameters, i.e., vehicle weight, cable model, road surface roughness, vehicle speed, longitudinal distance between vehicles. For this purpose, two steel composite cable-stayed bridges with 230- and 540-m main spans were selected. The results of the analysis were then compared with those of the influence line method that is currently being used in design practice. The road surface roughness was randomly generated based on ISO 8608, and the convergence of impact factors according to the number of generated road surfaces was evaluated to improve the reliability of the results. A9-d.o.f. tractor-trailer vehicle was used, and the vehicle motion was derived from Lagrange's equation. 3D finite element models for the selected cable-stayed bridges were constructed with truss elements having equivalent moduli for the cables, and with beam elements for the girders and the pylons. The direct integration method was used for the analysis of the bridge-vehicle interaction, and the analysis was conducted iteratively until the displacement error rate of the bridge was within the specified tolerance. It was acknowledged that the influence line method, which cannot consider the dynamic effect due to moving-vehicle motion, could underestimate the impact factors of the end-cables at the side spans, unlike moving-vehicle-load analysis.

• Korean Journal of Optics and Photonics
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• v.2 no.3
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• pp.139-148
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• 1991

A fiber-optic magnetic sensor system for the detection of small ac magnetic field(200Hz-2 kHz) was constructed. Magnetic field sensing part was fabricated by bonding a section of optical fiber to amorphous metallic glass(2605SC) having large magnetostriction effect. And with the directional coupler, all fiber type Mach-Zehnder interferometer was constructed to measure the variation of the external magnetic field by translating it into the optical phase shift in the interferometer. The signal fading problem of the interferometer, which is due to random phase drifts originated from the environment, i.e., temperature fluctuation, vibrations, etc., was elliminated by feedback phase compensation. This allows the sensitivity to be maintained at the maximum by keeping the interferometer in quadrature phase condition. The frequency response of metallic glass was found to be nearly flat in the range of 90 Hz-2 kHz and dc bias field for the maximum ac response was 3.5 Oe. The interferometer output showed good linearity over the range $\pm$0.5 Oe. For 1 kHz ac magnetic field the scale factor S and the minimum detectable magnetic field were measured to be 8.0 rad/Oe and $3X10^{-6} Oe/\sqrt{Hz}$at 1 Hz detection bandwidth respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.1
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• pp.40-46
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• 2000

The investigation and the analysis of soil chemical properties, microbial flora and cultural practices in plastic house of 60 farms (pepper 20, cucumber 20, oriental melon 20) were conducted in Chonnam area film. An amount of fertilizer application of farms was more than that of standard fertilizer application. That was phosphate at two and a half times, potassium at twice and manure at three times the amount of standard application. It was inferred that excessive fertilizer application would lead to salts accumulation in soil. Continuous cropping injury would be incurred by excesive salts accumulation in soil. Even if inorganic elements in soil culturing peppers, cucumbers and oriental melons were greater than optimum level, base-saturation degree of soil culturing peppers, cucumbers and oriental melons was 40:18:12, 55:16:14 and 40:27:11 respectively. That was lower than the optimum levels (60:15:5). Therefore, crops would be affected by uptake inhibition by nutrition imbalance. Density of Fusarium is related to plant decease in soil i.e. pepper $26.2{\times}10^2\;cfu\;g^{-1}$, cucumber $75.8{\times}10^2\;cfu\;g^{-1}$ and oriental melon $6.5{\times}10^2\;cfu\;g^{-1}$. B/F of soil planted with pepper, cucumber and oriental melon was 91.2, 80.4 and 18.8, respectively.

• Journal of Sericultural and Entomological Science
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• v.49 no.1
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• pp.24-27
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• 2007

Silkworm fed on the mulberry leaf mixed with silver nanoparticle to produce silver-nanoparticle embedded cocoon. Comparative analysis of silver content of cocoon shell, percentage of pupation and percentage of cocoon-shell weight showed that the optimum concentration and the feeding period of mulberry leaf mixed with silver nanoparticle were 500 ppm and the period from 3 day 5 instar to mounting of silkworm. The silver content of cocoon was observed variously by silkworm breedings. C212 variety makes pale yellow cocoon with the highest silver content(69%). Using the scanning electron microscope, we showed that the size of silver nanoparticles in silk was observed from 26.98 to 99.81nm. Silver-nanoparticle embedded silk is expected to use as high valuable application owing to the different functional properties including antibiotic characteristics and mechanical and electronic properties. The applicable fields expected is antistatic and/or electronic products with biological degradable natural materials.

• Korean Journal of Veterinary Research
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• v.35 no.3
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• pp.515-530
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• 1995

Coronaviridae에 속하는 transmissible gastroenteritis virus(TGEV)와 porcine epidemic diarrhea virus(PEDV)를 specific하게 detection할 수 있는 방법을 개발하고자 본 연구를 수행하였다. 두 바이러스 모두 RNA 바이러스이기 때문에 reverse transcription-polymerase chain reaction(RT-PCR)으로 nucleocapsid(N) protein gene의 cDNA를 증폭시켰다. SmaI으로 처리한 pTZ19R에 ligation시킨 후 염기서열을 밝히고자 sequencing하였다. 각각의 prototype virus와 비교하여 상동성을 밝혔다. 두 바이러스에 대한 cDNA probe를 제작하여 Southern blot hybridization을 실시하였다. TGEV의 경우 백신주인 P45와 병독주인 Miller strain을 사용하였다. cDNA를 증폭시키기 위해 N1/N1R과 N2/N2R 두 가지 primer를 이용한 결과, N1/N1R primer의 경우 586bp 크기의 PCR product를 얻을 수 있었고, N2/N2R primers로 582bp의 cDNA를 증폭시킬 수 있었다. PEDV 실험을 위하여 PED 임상 증상을 나타내는 분변을 이용하여 RT-PCR을 실시하였다. P2/P2R primer로 753bp의 PCR product를 얻을 수 있었다. TGEV의 두 가지 strain의 N protein gene을 sequencing하여 prototype인 Purdue strain과 염기서열 상동성을 조사한 결과, 97%이상의 높은 homology를 나타내었다. PED-V 역시 N protein gene을 sequencing하여 CV777과 염기서열 상동성을 조사한 결과 97%이상의 homology로 PEDV임을 알 수 있었다. TGEV와 PEDV의 염기서열을 비교한 결과 29%의 낮은 homology를 관찰할 수 있었다. 두 가지 바이러스의 N protein gene에 대한 cDNA probe를 제작하여 Southern blot hybridization을 한 결과, 각 바이러스에 매우 특이적 반응을 나타내었다.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.1-8
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• 1988

In order to get basic information for establishing weed control methods, weed distribution was surveyed at 15 days interval in garlic and red pepper fields at 8 locations in Chungnam Province. In garlic fields, 68 weed species(27 families) were distributed. Portulaca oleracea, Chenopodium album and Digitana sanguinalis were most dominant and Equisetum arvense, Alopecurus aequalis, and Setaria viridis dominant among them. Highest number of weeds emerged in May and dry weight or weeds was more heavy in June and summer broadleaf weeds were most abundant throughout garlic growing period. In red pepper fields, 38 weed species(17 families) were distributed, D. sanguinalis, Cyperus amuricus and P. oleracea were most dominant and Echinochloa crus-galli, Eleusine indica, D. violascens, and Centipeda minima also dominant among them. The highest number of weeds were emerged in June and summer, grasses and summer broadleaf weeds were more abundant in June and July. Seasonal Shannon's diversity index(H'), maximum diversity(Hmax') and eveness(J') for the Shannon diversity index, and Simpson index were high in both red pepper and garlic fields. Interspecific competition(probability for interspecific encounter) was more severe than intraspecific competiton.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.5 no.1
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• pp.62-67
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• 2002

Purpose: The aim of this study was to investigate the age of onset and the prevalence of lactose malabsorption in early childhood in Korea. Methods: We conducted a study of lactose malabsorption by breath hydrogen test in healthy children aged between 25~96 months old. Standard lactose loading (2 g lactose/kg, maximum 40g) test was done in 129 children and cow's milk (10 mL/kg) loading in 126 children followed by breath sampling of 60 and 120 minutes after the loading. An increase above baseline of 20 ppm or more was used as a criteria for positive responses. Results: The prevalence of lactose malabsorption was 7% in 25~36 months old, 19% in 37~48 months old, 35% in 49~60 months old, 55% in 61~72 months old, 82% in 72~84 months old, 80% in 85~96 months old children. Only 1% of the children showed positive result in breath hydrogen test after the cow's milk challenge. Conclusion: The prevalence of lactose malabsorption was increased between 37 months and 60 months of age, reached to adult level of prevalence after 72 months of age. When physiological dose of lactose was used as the challenge, the number of lactose malabsorbers become clinically insignificant.

• Information Systems Review
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• v.17 no.3
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• pp.95-111
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• 2015

The recommendation system automatically provides the predicted items which are expected to be purchased by analyzing the previous customer behaviors. This recommendation system has been applied to many e-commerce businesses, and it is generating positive effects on user convenience as well as the company's revenue. However, there are several limitations of the existing recommendation systems. They do not reflect specific criteria for evaluating products or the factors that affect customer buying decisions. Thus, our research proposes a collaborative recommendation model algorithm that utilizes each customer's online product reviews. This study deploys topic modeling method for customer opinion mining. Also, it adopts a kernel-based machine learning concept by selecting kernels explaining individual similarities in accordance with customers' purchase history and online reviews. Our study further applies a multiple kernel learning algorithm to integrate the kernelsinto a combined model for predicting the product ratings, and it verifies its validity with a data set (including purchased item, product rating, and online review) of BestBuy, an online consumer electronics store. This study theoretically implicates by suggesting a new method for the online recommendation system, i.e., a collaborative recommendation method using topic modeling and kernel-based learning.

• Journal of Animal Environmental Science
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• v.15 no.2
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• pp.131-138
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• 2009

This study was conducted to find ways to control environment with the difference between body temperature and background temperature based on swine activity, and to apply to the environment control system of swine barns based on the findings. Following are the results. 1. Swine activity related to background temperature was achieved as color images and swine activity status was categorized into cold, comfortable, and hot periods with visualization system (thermal image system). 2. Thermal image system consisted of an infrared CCD camera, an image processing board - DIF (TH3100), an main computer (400Hz, 128M, 586 Pentium model) with C++ program installed. 3. Thermal image system categorizing temperatures into cold, comfortable, and hot was applicable to the environment control system of swine barns 4. Feed intake was higher in cold temperature, and finishing weight and weight gain per day in cold temperature were lower than others (p<0.05).