• 한국초등수학교육학회지
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• 제10권1호
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• pp.89-106
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• 2006

학생들이 수학학습을 하는데 있어서 경험하게 되는 여러 가지 부정적인 경험과 정서들은 학년이 올라감에 따라 학생들의 수학불안의 요인이 되며, 이러한 수학불안은 효과적인 수학성취도에 부정적인 영향을 미친다. 따라서 본 연구에서는 초등학교 학생들의 수학불안 요인을 수학교과 요인, 학습자 태도 요인, 교사 요인, 환경요인의 4개 영역으로 나누어 분석한 후, 수학불안 요인들이 학년 및 성별 간에 차이를 보이는지에 대해 살펴보고자 한다. 또한 수학불안 요인들은 수학성취도와 어떠한 관계가 있는지 알아보고자 한다. 그리하여 초등학생의 수학불안 요인 처치의 중요성을 인식하고 그 방안을 모색하는데 도움을 주고자 한다.

• 조명전기설비학회논문지
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• 제23권9호
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• pp.91-97
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• 2009

전력케이블 사고 발생시에는 사고원인을 규명 해야하며, 본 연구에서는 FMEA 방법을 이용하여 케이블 사고에 대한 자가원인 진단 시스템을 구축하였다. 자가원인 진단 시스템은 사고당시의 데이터 입력, 픽토그래프를 통한 사고형태의 표현, FMEA 방식을 적용한 사고확률 값으로 구성되어 있으며, 각 선택에 따라 사고원인에 대한 사고가능성이 결과로 나타나게 된다. 또한 실제 케이블 사고사례의 원인분석을 통해 자가원인 진단 시스템을 검증한 결과, 이 시스템은 실제 분석결과와 잘 일치되었다.

• 한국기계가공학회지
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• 제17권6호
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• pp.1-6
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• 2018

Recently nano meter size pattern (sub-micro scale) can be machined mechanically using a diamond tool. Many studies have found a 'size effect' which referred to a specific cutting energy increase with the decrease in the uncut chip thickness at micro scale machining. A new analysis method was suggested in order to observe 'size effect' in nano scale machining and to verify the cause of the 'size effect' in this study. The diamond tool was indented to a vertical depth of 1,000nm depth in order to simplify the stress state and the normal force was measured continuously. The tip rounding was measured quantitatively by AFM. Based on the measurements and theoretical analysis, it was verified that the main cause of the 'size effect' in nano scale machining is geometrically necessary dislocations, one of the intrinsic material characteristics. st before tool failure.

• Toxicological Research
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• 제21권2호
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• pp.129-134
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• 2005

Styrene is a commercially important chemical used mainly in the production of plastics. A toxic effect exerted by styrene exposure may cause infertility, congenital anomalies or death in offspring. Treatment with styrene for 0, 50, 100, and 500 mg/kg for 5 days in Sprague-Dawley rats significantly decreased sperm motilities and sperm counts while sperm abnormalities were significantly increased. To determine the relationship between changes in sperm motilities and roles of reactive oxygen species (ROS), we determined the effect of styrene on ROS production and mRNA expression of antioxidant enzymes in rats. ROS production was enhanced by styrene treatment in a dose-dependent manner. The mRNA expression of catalase and superoxide dismutase (SOD) 2 was strongly suppressed by styrene treatment although SOD1 or glutathione peroxidase (GPX) 4 expressions were not significantly changed. Taken together, these results indicate that styrene may cause toxic effect in rat sperm cells by enhancing oxidative stresses.

• 전기학회논문지
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• 제61권6호
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• pp.821-826
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• 2012

The streaming electrification process of vegetable insulating oils occurring when the oils contacted with solid material in a high power transformer circulation system seems to cause electrical discharge incidents and may cause failures. We therefore measured the dielectric breakdown voltage tendency of vegetable insulating oils flowing on the surface of the charging device with various velocity and temperature. First, the relation between the velocity and breakdown voltage tendency of vegetable oils, can be explained by volume effect and v-t effect. Second, experimental results show that applied voltage have little effect on dielectric breakdown voltage, when vegetable insulating oils used for large power transformer.

• 산업공학
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• 제21권2호
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• pp.161-169
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• 2008

Normally, suppliers have to decide on what, how much, and when to replenish stocks of goods based on a data flow generated by a vendor managed inventory(VMI) system. But information from supply chain is often misleading. It is common for such data to be distorted by a lack of coordination and synchronization across several business entities managing different supply chain operations. This phenomenon is called the 'bullwhip effect(BwE)'. Many researchers, working over many years, have studied the reasons for the BwE. They have proposed various remedies, but this phenomenon persists. Though overlooked in previous research, this paper reveals that the 'lot size' of a supply chain of distribution is indeed the main cause of the BwE. In addition, some problems in the existing methods of measuring the BwE are identified and a revised much improved method of measurement is suggested.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1999년도 유체기계 연구개발 발표회 논문집
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• pp.109-113
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• 1999

Thermal mass flow meter (TMF) is used measuring the small mass flow rate of gases. Generally, flow rate measuring accuracy of TMF is $\pm2{\%}$ of full scale. TMF is manufactured for specified working pressure and specified working gas by customer. If it were applied for different working pressure and gases, flow rate measurement accuracy decreased dramatically. In this study, a TMF tested with three different gases and pressure range of 0.2 MPa to 1.0 MPa. Effect of specific heat cause to increase flow measurement error as much as ratio of specific heat compare with reference gas. Pressure change cause to increase flowrate measurement deviation about $-0.2{\%}$ as the working pressure decreased 0.1 MPa.

• 복식
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• 제59권6호
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• pp.1-15
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• 2009

The purpose of this study is to examine the effect of the cause marketing on fashion brand credibility, purchase and words of mouth ("WOM") intentions. This study adopted a survey method with the questionnaire. Data were collected from respondents who were graduated from higher than elementary school students. The data were analyzed by using statistic methods such as frequency analysis, factor analysis, reliability test and structural equation modelling. The results of the data analysis of this study are as follows; firstly, brand familiarity and customer attitude have a directly positive effect on the credibility, purchase and WOM intentions. Fashion business companies should work up the ways of communications with the customers besides cause marketing for the brand familiarity. It is necessary for customers to be known about how the fashion business companies participate in cause marketing to enhance the value of positive brand attitude. Secondly, while the brand familiarity on the credibility, purchase and WOM intentions are effective to female customers, the brand attitude is effective to male customers. Thirdly, even though it was showed that the credibility of fashion brands have no significant effects on purchase and WOM intention, it is due to its own nature of fashion business and it is founded in preceding research that high-involved fashion products may have different results in comparison with the practical products.

• 디지털융복합연구
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• 제12권10호
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• pp.605-613
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• 2014

해양레저 관광 활성화를 위해 해양레저스포츠 체험선택과 체험효과, 체험만족 간의 관계를 연구하고자 설문지를 제작한 후 보령지역을 방문하여 조사 분석을 실시하는 연구를 수행한 결과 다음의 결론을 얻었다. 첫째, 해양레저스포츠의 선택중요는 선택만족에 긍정적인 영향을 미치는 것으로 나타났다. 둘째, 해양레저스포츠의 선택중요는 체험효과에 긍정적인 영향을 미치는 것으로 나타났다. 셋째, 해양레저스포츠의 선택만족은 체험효과에 긍정적인 영향을 미치는 것으로 나타났다. 넷째, 해양레저스포츠 방문객들은 모타보트, 바나나보트, 요트 체험을 선호하는 것으로 조사되었다. 다섯째, 해양레저체험센터 건립시에는 장비대여소, 안전시설, 해양레저체험시설이 포함되어야 한다.

• 식품산업과 영양
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• 제4권1호
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• pp.26-30
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• 1999