• Water Engineering Research
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• 제1권4호
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• pp.309-320
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• 2000

In this study, laboratory study of the behavior of wastewater discharged from the Boston ocean outfall was compared with the predictions of mathematical models. The dta sets cover broad ranges of discharge conditions and oceanic conditions, and are associated with a typical type of outfall discharges with multiport diffusers. The laboratory data sets were obtained in density stratified towing tanks. These data sets were used to evaluate four commonly used models: UM, UDKHDEN, RSB and CORMI$\times$2 for minimum dilution, the height to the top of the wastefield, and wastefield thickness. For minimum diluation and height to the top of the wastefield, UM and RSB predictions agree well with laboratory data. UDKHDEN overestimated the minimum dilution and height to the top of the wastefield while CORMI$\times$2 underestimated these values. All of the model predictions for the wastefield thickness were widely scattered. about the measured values. The hydraulic model study reproduced the major features observed in the laboratory. It also afforded considerable insight into the mechanics of mixing of multiport risers which could not have been obtained either from the laboratory test or the mathematical models.

• Journal of Korean Society for Atmospheric Environment
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• 제9권E호
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• pp.397-400
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• 1993

The possible air pollution problems in a proposed underground highway are discussed using carbon monoxide (CO) as an indicator. Carbon monoxide concentrations in the underground highway depend on several factors, including the size of tunnel, the number of automobiles, the CO emission rate, and the tunnel ventilation rate. Using the estimated values, CO concentrations in the underground highway can be predicted. Without proper ventilation system, CO concentration in the underground highway can be dangerous level. However, the cost of operating the mandatory mechanical ventilation system may be tremendouslyy high and may be technically unrealistic to implement. If the underground highway is constructed with proper ventilation system, a continuous air pollution monitoring system with alarming function must be installed to alert personnel of serious air pollution built up in the underground highway. Traffic must be restricted, whenever the inside air pollution levels exceed agreed values. Short distances between evacuation exits are necessary for emergency situations or malfunction of ventilation system.

• International Journal of Control, Automation, and Systems
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• 제2권3호
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• pp.390-397
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• 2004

This paper presents the design and testing of a multi-channel vibrotactile display. It is composed of a cylindrical handle with four embedded vibrating elements driven by piezoelectric beams. Vibrations are transmitted to the hands through arrays of pins. The device was tested in sensory substitution for conveying force information during a teleoperated peg insertion. Results show that the device is effective in reducing peak forces during the insertion task.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제23권2호
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• pp.93-111
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• 2020

The purpose of this study was to examine mathematics teachers' perceptions of multicultural education. To achieve this goal, the study explored how 10 elementary mathematics teachers noticed multicultural content in a mathematics textbook. Building upon noticing framework (Jacobs, Lamb, & Philipp, 2010), we first examined teachers' attention toward multicultural content in a mathematics textbook. Then, we examined teachers' interpretation of the content. We employed a content analysis approach to examine the collected data. The results indicated that most mathematics teachers held a content integration perspective. Their view was that "multicultural education" referred to learning about the diverse cultures of different countries. Moreover, although they noticed some multicultural content in the textbook, they wanted to discuss them in superficially descriptive ways and avoid talking about social justice issues. Additionally, some teachers believed that mathematics is a culture-free subject. They argued that multicultural content should not be presented in mathematics textbooks. We also discussed uncommon themes, which were reported by only a few mathematics teachers.

• 비파괴검사학회지
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• 제22권6호
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• pp.599-608
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• 2002

The mechanical properties of mullite $(3Al_2O_3\;2SiO_2)$ environmental barrier coatings are determined using a laser-based ultrasonic system. The waveforms generated by a laser source in mullite coatings in the $1-20{\mu}m$ thickness range are evaluated theoretically using the integral transform technique. It is shown that the laser source generated the two lowest order SAW modes in these systems. Experimental waveforms are generated using a 600ps pulsed Nd:YAG microchip laser and detected using a stabilized Michelson interferometer. The dispersion curves for the generated modes are extracted from the experimental data and the mechanical properties of the coatings are obtained by minimizing the error between the measured and calculated velocity values. The waveforms generated in mullite coatings agree well with theory and laser-based ultrasonics is shown to provide an effective tool for the nondestructive evaluation of ceramic coatings.

• 유통과학연구
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• 제8권1호
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• pp.5-11
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• 2010

This study addresses a shift, generally positive, in the acceptance and adoption of mobile commerce. The study, based on data collected using a survey questionnaire from mobile phone users in South Korea, examined the relationships using factor analysis and multiple regression analysis methods. The results showed equal positive adoption rates across all demographics of age, education, and income, except for gender, in terms of attitudes toward mobile shopping. The rate of mobile commerce adoption was relatively stronger among females than males. This finding provides new developments to mobile service providers on the effect of demographic profile on consumers'behavior and attitudes toward mobile shopping. Based on the results of the study, practical implications for marketing strategies in mobile commerce markets are suggested.

• 유통과학연구
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• 제10권6호
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• pp.7-15
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• 2012

The paper deals with the impact of information and communications technology on carbon emissions and economic growth in South Korea. The quarterly time series data from the first quarter of 1970 to the third quarter of 2010 (163 observations) are collected and retrieved from the Bank of Korea database. The paper examines long-run equilibrium relationships using cointegration techniques and Granger causality with vector error correction models. In directional causality tests, information and communications technology shows highly significant positive effects on economic growth and marginal effect on carbon emissions. Carbon emissions and economic growth exhibit an inverse relationship with each other; that is, carbon emissions have an inverse relation to economic growth and economic growth does not significantly affect carbon emissions in South Korea. We also note possible implications regarding growth policies and the information communications technology and "green" technology sectors for economies in the range represented by Korea's 1970 - 2010 data.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제24권1호
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• pp.29-47
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• 2021

The purpose of this study was to examine what factors affect the construction of preservice white mathematics teachers' racial identities and the relationship between their racial identities and Culturally Relevant Teaching (CRT) practices. We examined five white female preservice teachers who enrolled in an elementary mathematics methods course at a private university in the US. We collected data consisting of lesson plans, semi-structured interviews, and reflection of a taught lesson in the 2018 fall term and examined them using qualitative research methods. We found that preservice teachers' racial identities were affected by their backgrounds, K-12 school experiences, and practicum school environment. We also found a relationship between teachers' sensitivity to racial issues and their endorsement of CRT strategies. The findings also revealed that the relationships were mediated by practicum school contexts. Based on the findings, we provided practical implications for the teacher education programs.

• 식물병연구
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• 제29권3호
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• pp.299-303
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• 2023

Rust symptoms on Meliosma myriantha trees have been noticed during disease surveys in Korea since 2010, with a high disease incidence frequently surpassing 90%. The causal fungus of the rust disease was identified as Neophysopella vitis based on the morphological investigation and molecular sequence analysis of the internal transcribed spacer (ITS) and large subunit (LSU) rDNA regions. This is the first report of rust disease caused by N. vitis on M. myriantha in Korea. A pathogenicity assay proved that M. myriantha serves as the aecial host of N. vitis as spermogonia and aeciospores were produced, which can infect the two uredinial hosts, Boston ivy (Parthenocissus tricuspidata) and Virginia creeper (Parthenocissus quinquefolia).

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 추계학술대회
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• pp.586-589
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• 2021

본 논문에서는 RT(Robot Technology) 및 관련 산업을 중심으로 현대자동차그룹의 21세기를 이끌어갈 새로운 중추 산업 로봇기술의 보스턴 다이내믹스 M&A를 통해 모빌리티 분야에 현대자동차의 선진사례와 기술을 소개한다.