• Economic and Environmental Geology
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• v.4 no.1
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• pp.19-32
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• 1971

Summarizing the past and recent data on pre-Cambrian System in Eastern Asia, it can be concluded that the pre-Cambrian System are composed of the sediments of having four cycles of sedimentation. It is also known that most of pre-Cambrian Systems known so far belong to either one of transgression facies or regression facies in the four sedimentation cycles. The pre-Cambrian Systems can be divided into four stages, that is, Sinian, Hutoan, Liahoan, and Taishanian stage. It is supposed that all pre-Cambrian Systems in Korea will belong to one of these four cycle sedimentations. Therefore, the reasonable way of study of Korean pre-Cambrian Systems is to investigate which stage they belong to.

• Research in Mathematical Education
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• v.19 no.2
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• pp.89-100
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• 2015

The study investigated pre-service teachers' knowledge and computational skills by using Triangular Arithmagon. Participants included 90 pre-service teachers from two schools in the United States and Taiwan. The Triangular Arithmagons Test (TAT) was used to measure pre-service teachers' performance in whole number, fractions, and decimals operations (i.e., addition, subtraction, multiplication, and division), each of which included level-1 (basic) and level-2 (advanced) tests. MANOVA analysis was performed to compare the performance between teachers from the United States and Taiwan. Results indicated that overall, pre-service teachers in Taiwan outperformed those in the United States, especially on the advanced-level tests. Pre-service teachers in the United States were found to have poor ability of solving complex operation problems. Different curriculum plans and teaching methods may lead to the performance gap between the two countries.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.12 no.2
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• pp.42-51
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• 2006

The purpose of this study was effect of pilates exercise program on obesity pre-obese adult sixteen (men 3, women 13). The pilates exercise program was provided to subject for 4weeks (3 time a week) Measurements of pre and post 2weeks, and post 4weeks experiment were BMI (Body Mass Index), WHR(Waist-hip Ratio). The result were as follows: 1. The BMI was decreased in pre - exercise 2weeks, pre - exercise 4weeks but there was no statistically. There was significant difference between pre - exercise-4weeks. 2. The WHR was no significant difference between pre - exercise-2 weeks and pre - exercise-2 weeks and 2-4 weeks everybody.

• The Journal of the Acoustical Society of Korea
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• v.4 no.3
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• pp.33-41
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• 1985

이 논문에서는 frequency-weighted MSE를 최소화하는 적응 pre-filter와 post-filter를 음성파형 부호화기에 적용했을 때의 성능을 분석한다. 먼저 여러 다양한 pre-filter와 post-filter에 의한 noise shaping 효과를 이론적으로 보여준다. 그리고 frequency-weighted SNR 척도를 사용하여 적응 pre-filter 와 post filter에 의한 성능면에서의 이득을 이론적으로 유도한다. 적응 pre-filter와 post-filter를 ADM과 ADPCM 부호화기에 적용해본 결과에 의하면 음성파형 부호화기의 성능을 FWSNR\sub SEG\ 척도로 약 3dB 정도 개선할 수 있음을 알 수있다. 또한 pre-filter와 post-filter를 사용하면 청각적으로 중요한 영향을 미치는 1kHz에서 3kHz 사이의 양자화 잡음을 효과적으로 줄일 수 있다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.41-46
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• 1996

In this study, unsintered and pre-sintered low purity alumina ceramics were machined with various tools to clarify the machinability, optimum tool materials and optimum cutting conditions. The main conclusions obtained were as follows. (1)In the case of dry cutting, the sintered diamond and natural diamond tools exhibit better performance in machining of the ceramic pre-sintered at lower temperature, and the tool lives of both tools in machining the ceramics pre-sintered at high temperature becomes extremely short. (2)The performance of CBN tool becomes better in dry machining of the ceramics pre-sintered at higher temperature. (3)When the pre-sintered ceramics were wet machined with sintered diamond, the tool life becomes considerably long, and higher cutting speed can be used than in the case of the CBN and ceramic tools, the tool lives becomes shorter at wet cutting than at dry cutting, especially exhibiting extremely short tool life in wet cutting with ceramic tool.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.2
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• pp.49-59
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• 1992

In our researches we made mix-design, with the mixing ratio and pre-cracked ratio of steel fibrous different from each other, building the steel fibrous concrete beam which had pre-cracks. To obtain the fracture characteristics of steel fibrous reinforced concrete, series of experiment were conducted on pre-cracked beam subjected to 3-point bending. Thus, we carried out experiments on the destructive characteristics of its pre-crack and post-crack and the result is as follows. 1. The compressive strength of steel fibrous concrete beam increased more slightly than plane beam, and the tensile strength increased 37%, 59%, 94% and 121% respectively when the amount of fibrous was 0.5%, 0.1% 1.5%, and 1.75% respectively. 2. As the amount of steel fibrous mixing increased ant the steel fibrous inhibited the crack growth, the crack condition of steel fibrous concrete beam was retarded irregularly, and this increased fracture load. 3. The defiance of destruction was reduced in the ratio of 1.35 times and 1.22 times respectively when the length of pre-crack was each 2cm and 4cm in comparison with the case of being without the length, and was similar to that of plane beam when the amount of steel fibrous mixing was below 1.0%, and increased linearly when it as above 1.0%. 4. The experimental formula seeking fracture energy was follows and thus we found that the value of fracture energy depended upon tensile strength and the size of speciment. $G_f=K\;{\cdot}\;f_f^'{\cdot}$da/Ec 5. We observed that in the load-strain curve of steel fibrous concrete beam the progress of the crack became slow, compared with plane beam because the crack condition became long to the extent of about 10 times. Concrete was faultiest brittleness fracture through the study, it was known ductile.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.19-27
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• 2017

The purpose of this study was to analyze the differences of creativity according to major of college students focusing on pre-service early childhood teachers, pre-designers and pre-engineers. The subjects were 132 four grade of university students attending K and T university in Busan, Korea. Data were analyzed with one-way MANOVA to find out the differences of creativity according to their major. Results of this study as follows: first, overall creativity was significantly higher in preliminary designers than pre-service early childhood teachers and pre-engineers. Second, the fluency of pre-service early childhood teachers and pre-designers was significantly higher than that of pre-service engineers. The abstraction was significantly higher in pre-service early childhood teachers than pre-engineers. The elaboration of pre-designers was significantly higher than that of pre-service teachers and pre-engineers. Openness was significantly higher in pre-designers than pre-engineers, and pre-engineers were significantly higher than pre-service early childhood teachers. Therefore, this study suggests that the major in creativity curriculum and program development for college students should be considered, and the results of this study will be used as basic data of the creativity education program.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.27-33
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• 2016

This study was carried out in order to investigate the effect of binder properties in pre-coating layer on the characteristics of top-coating layer and print mottle of coated paper. Four different latices were used as a binder in pre-coating layer, and coating color prepared with a same formulation was applied for top-coating. The properties and print mottle of coated paper were evaluated. It was found that glass transition temperature (Tg) was the important factor to control the properties of pre- and top-coating layer. PPS roughness of coated paper was decreased and paper gloss was increased with applying binder which has lower Tg. Properties of top-coating layer were affected by the binder used in pre-coating layer. Print mottle of coated paper was improved with using binder which has lower Tg in pre-coating layer. These results indicate that final printability and properties of top-coating layer can be improved with using suitable binder in pre-coating layer.

• Journal of Korean Physical Therapy Science
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• v.7 no.1
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• pp.353-365
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• 2000

The purpose of this study were to compare the lumbar extensor strength between pre op patients group and after 6 weeks post op patients group. To evaluate lumbar extensor strength of total 273 patients with HIVD. Lumbar extensor strength was measured in 151 male patients and 122 female patients(Lumbar extensor strength was measured in 91 PELD patients group and 182 OLM group patients) by Medx lumbar extension machine. Maximum voluntary lumbar extension strength was appear $149.36{\pm}61.92ft$-lbs in pre op of PELD group, $158.47{\pm}54.67ft$-lbs in post op of PELD group and $135.54{\pm}54.24ft$-lbs in pre op of OLM group. $147.19{\pm}52.42ft$-lbs in post op of OLM group in male. Maximum voluntary lumbar extension strength was appear $83.85{\pm}30.22ft$-lbs in pre op of PELD group. $92.99{\pm}28.66ft$-lbs in post op of PELD group and $75.16{\pm}24.98ft$-lbs in pre op of OLM group, $79.88{\pm}25.25ft$-lbs in post op of OLM group in female. Male and female lumbar extension strength was statistically significant difference(P<.05). Lumbar flexion/extension ratio of the two group was 2.14:1 pre op and 2.05:1 post op in lumbar flexion 72 and 0 degree. The ratio of post op group was lesser than pre op group.

• New & Renewable Energy
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• v.10 no.1
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• pp.20-29
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• 2014

The present study investigated the effects of thermal pre-treatment on the enhancement of anaerobic biodegradability of waste activated sludge at varied TS concentration levels. The activated sludges were thermally oxidized for 30 minutes at $80{\sim}200^{\circ}C$ with varied TS concentrations (2%, 4% and 6%). and then, sludge characteristics, solubilization efficiency and methane production yield of thermally pre-treated sludges were analyzed. The higher the temperature in the thermal pre-treatment, the higher the concentration levels of dissolved matters such as $SCOD_{Cr}$, $NH_4{^+}$ and VFAs, which indicates that the thermal pre-treatment facilitates the hydrolysis and acid fermentation. Furthermore, the solubilization efficiency was increased in proportion to the temperature rise at all TS concentrations and was reached at 68.9%, 55.6% and 53.1%, respectively, at $200^{\circ}C$. In the BMP test of the pre-treated sludges, higher methane production yields were observed as 0.313. 0.314 and $0.299m^3\;CH_4/kg\;VS_{add}$ at the condition of TS 2% ($160^{\circ}C$), 4% ($160^{\circ}C$) and 6% ($180^{\circ}C$), respectively, and degradation rate was increased by 84%, 79% and 65% compared with non-pretreated waste activated sludge. These findings suggest the effectiveness of thermal pre-treatment of waste activated sludge for anaerobic biodegradable process.