• Korean Journal of Ecology and Environment
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• v.49 no.3
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• pp.228-235
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• 2016

Aquatic ecosystems are receiving various harmful effects due to anthropogenic chemical pollutions. To protect wildlife, risk assessments of the chemicals are conducted using reference indexes of toxicity estimated by species-level laboratory tests and/or micro-/mesocosm community-level studies. However, the existing micro-/mesocosm communities are structurally too complicated, and it is also difficult to compare the experimental results directly with those from species-level tests. Here, we developed a procedure of a simple bi-trophic microcosm experiment which contains the common species (a green algae, Pseudokirchneriella subcapitata and a cladoceran, Daphnia magna) for testing chemical toxicities. For the proper operation of bitrophic microcosm experiment, the minimum required concentration of primary producer (P. subcapitata) is $5{\times}10^5cells\;mL^{-1}$. The microcosm system showed higher stability when the initially introduced D. magna population was composed of neonates (<24-h old) than adults and those mixture. This simple microcosm system would be an applicable tool to estimate the disturbing impacts of pollutants on plant-herbivore interactions, and linking the species- and population-/community level risk assessments in the future studies.

• School Mathematics
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• v.13 no.4
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• pp.697-716
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• 2011

It is known that Korean students performs very well in mathematics but show poor attitude toward mathematics. However, attitude itself is an important goal of education and it also promotes students learning. Therefore, it is important and urgent for us to find a way to improve students' attitude toward mathematics. In this article, we tried to examine characteristics of Korean students' attitude toward mathematics and identify student and school level factors affecting it. For this purpose, we analysed National Assessment of Educational Achievement (NAEA) data in 2007 when NAEA was conducted especially focused on mathematics. Main findings of this research are as follows. First, we found that attitude toward mathematics got lower as students advanced to higher grades. And among 3 sub-domains of attitude toward mathematics, interest and self-confidence were lower than perception of value of mathematics. Secondly, attitude toward mathematics was mainly affected by student background variables such as gender, achievement, participation in private tutoring, father's education level. And while school factors contributed relatively little to students' attitude toward mathematics, teacher's perception on value of school education was positively related with students' attitude in high schools and emphasis on assessment was negatively related with students' attitude in elementary schools.

• School Mathematics
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• v.13 no.3
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• pp.485-500
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• 2011

The purpose of this study is to investigate how elementary mathematics teachers use and implement a reform-oriented mathematics curriculum material, Everyday Mathematics, and to examine what features the curriculum material has. Eight elementary mathematics teachers in the United States participated in the study. Data sources consist of teacher classroom observation write-ups, interviews, and the curriculum material. The results from the analysis of the curriculum material suggest that 80 percent of the tasks are at the high-level in terms of cognitive demand and 26 percent of tasks are identified as transparent. The results also show that the teachers appeared to adapt the curriculum material and partially take suggestions or activities out of the curriculum material in enacting them in their mathematics classrooms. The analysis of enacted tasks suggests that the levels of cognitive demand were shifted from high-level to low-level; 27 percent of the high-level tasks in the curriculum material were maintained at the high-level as enacted in the mathematics classrooms. The level of cognitive demand shifted in many cases; shifts from high-level to low-level occurred. This contributes to the curriculum material not being transparent to teachers.

• Korean journal of food and cookery science
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• v.29 no.6
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• pp.725-731
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• 2013

This study investigates the quality of strawberry jam containing different quantities of strawberry. Strawberry jam was prepared by the addition of 70-30%(w/w) strawberry puree, Sweetness, pH, total acidity, color, anthocyanin and pectin content, texture, free sugar, and organic acid content of the samples were measured. Decrease in the quantity of the strawberry puree led to a decrease in the following: total acidity(significance value p<0.05), anthocyanin, pectin, total free sugar, frutose, glucose, sucrose, and, organic acid content, namely oxalic acid, citric acid, malic acid, succinic acid, and formic acid. A texture profile analysis showed reduction in the hardness, gumminess, and chewiness of the jam. At the same time, decrease in the puree quantity also led to an increase in the sweetness, pH, L-value, a-value and b-value(significance value p<0.05) of the jam. These results promote, the consumption of fruit that are high in fruit, low in sugar, and do not contain any chemical additives.

• Bulletin of Food Technology
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• v.16 no.3
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• pp.19-72
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• 2003

고도의 정보사회가 될 것으로 예견되는 21세기 전 세계는 창의적이고 원천적인 과학기술을 지속적으로 창출하면서 선진적 우위확보를 위해 치열한 경쟁을 벌이고 있다. 우리나라도 지금까지 이룩한 경제성장을 발판으로 이제부터는 더욱 생산적이고 독창적인 세계 일류 지식과 과학기술을 창출해 내야 할 위치에 있다. 세계적으로 새로운 지식은 대부분 학술지와 도서를 통해 발표되고 있으며, 미국의 과학정보기구인 ISI(Institute for Scientific Information)는 세계의 우수 학술지를 평가하여 그 중에서 가장 영향력이 높은 3~4%의 학술지를 SCI(Science Citation Index), SSIC(Social Science Citation Index), AHCI(Arts and Humanities Citation Index)로 전별하여 발표하고 있음은 잘 알려진 바와 같다. 우리 학계에서도 수 년 전부터 연구업적 등의 평가에 이들 분류를 적극 활용하고 있으며, 개개의 연구자들도 연구성과를 SCI 등에 등재된 학술지에 발표하기 위한 노력을 배가하고 있는 실정이다. 그러나 안타까운 것은 우리나라에서 발간되는 학술지 중 과학기술 분야 단 5종만이 SCI에 등재되어 있을 뿐이어서 우리의 학문이 세계적으로 교류되고 인정받는데 상대적으로 불리한 위치에 있다는 사실이다. 국내 학술지가 이들Index에 등재될 경우 우리의 연구성과가 보다 빠르고 쉽게 국제적으로 소개.인정되며, 이는 우리의 과학기술 수준을 한 단계 높이는데 첩경이 될 것이라는 점은 의심의 여지가 없다. 과학기술 평가과정은 측정 가능한 연구투자와 연구결과 현상으로 간주할 수 있는데, 일반적으로 연구투자는 연구투자에 필요한 모든 요소들이 실체적이며 평가하는 데에 있어서 인력, 재정 자원, 장비, 재료, 건물 등과 같이 구체적이고 경험을 요구하지 않기 때문에 그 모든 연구결과보다 평가하기가 용이하나 과학기술의 연구결과는 연구 과정을 통해 보다 비실체적이고 양적으로 측정하기 어려운 지식으로 구성되어 있어 평가하는데 어려움이 뒤따른다. 과학기술 연구결과를 양적이나 질적으로 측정하는데 있어 일반적으로 이용되는 시스템은 없으나 국가의 과학기술 수준은 보통 그 나라 과학기술 활동의 연구결과를 과학기술 생산성이나 연구결과물 즉 논문 등의 출판을 통한 배포나 인용분석 등에 기초한 양적 평가지표를 이용해 측정하는 서지적 방법에 의해 평가되고 있다.연구활동 결과로 발표된 연구논문은 새로운 연구논문의 자료로 인용되게 되는데, 일반적으로 인용이 많이 된 논문일수록 질적인 가치가 높다고 하므로 논문의 발표량과 인용된 횟수는 연구활동을 평가하는 척도로 활용점에 따라 과학기술분야 논문의 국가별, 기관별, 분야별 논문수와 피인용도는 과학기술 수준 평가의 척도가 될 수 있으며 이러한 평가는 과학기술 정책 수립 및 투자, 연구활동에 대한 평가 등의 중요한 자료로 활용될 수 있다. 과학기술분야 전반에 걸친 SCI 기반의 NSI, NCR 데이터베이스를 분석하여 우리나라 과학기술분야의 수준을 평가할 수 있는 지표를 산출하여 우리나라의 과학기술 수준을 정확히 파악하고, 세계 추세를 분석하여 앞으로 나아갈 정책방향을 설정하는데 도움이 되도록 하며, 국내 기관별, 분야별 분석을 통하여 과학기술 수준을 평가할 수 있는 객관적인 자료를 제공함과 동시에 국내 연구 인력간의 건전한 경쟁을 유도하여 과학기술 발전에 기여하고자 한다.

• Journal of IKEEE
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• v.24 no.3
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• pp.913-916
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• 2020

In this paper, we propose the development of nitrogen cooling equipment for personalized local area. The proposed equipment consists of a cold air supply module, a body, and nitrogen injection with the following characteristics. First, it automatically controls the amount and time of cold air supply by utilizing information measuring skin temperature with volumetric temperature sensors, so it can have a competitive edge in function by ensuring complete safety. Second, if the distance measuring sensor is applied to the skin for more than a certain distance, it can block the cold air or control the discharge of nitrogen in conjunction with the control GUI to improve the efficiency of higher cooling therapy while providing safe management. Third, by installing a control module that can control the supply of nitrogen, the cost of maintenance can be minimized by minimizing the loss of nitrogen. Experiments at an external testing agency to evaluate the performance of the proposed equipment showed that the accuracy of the temperature sensor was measured in the range of ±3.8%, which is lower than the world's highest level(±5%), with a range of 110℃ to -160℃ similar to the world's highest level. Distance accuracy was measured in the range of ±3.0%, lower than the world's highest level(±5%), and weight accuracy in the range of ±0.1%, lower than the world's highest level(±5%). In addition, emission control was measured in four stages, higher than the world's highest level(stage 1) and nitrogen use was measured at 0.8L/min below the world's highest(6L/min). Therefore, the effectiveness of the methods proposed in this paper was demonstrated because they produced the same results as the world's highest levels.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.317-327
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• 2012

The purpose of present study was to observe the path and influencing effects between socioeconomic class (SEC), health practices and self-rated health(SRH) by the age bracket. The subjects were 4,987 adults over 25 years old who participated in the 2008 Korean National Examination Health and Nutrition Survey and could be classified into SEC in terms of the three characteristics: education, income and occupation. Path analysis was conducted with the effects of health behaviors execution on the differences in SRH, and the complex samples analysis executed by chi-square test, t-test, ANOVA. As the result, lower SRH level paralleled with the lower SEC, and more health behaviors had differed by SEC in the younger and middle aged group. The lower SEC, the lower SRH: non-smoking and weight control for younger women and exercise for aged men had indirect effects as parameters. In conclusion, when planning a health promotion program, to select the correct target populations with consideration of the age bracket, gender and SEC and to establish tailored contents fit for each of the population would be important.

• Journal of The Korean Association For Science Education
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• v.22 no.2
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• pp.215-229
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• 2002

This study is to analyze the contents related to 'state of water', 'state change of water', and 'conditions of state change' in K-12 science textbooks. For this, we analyzed textbooks based on the 5th kindergarten curriculum, the 6th elementary school science curriculum and the 6th middle school science curriculum. Findings show that some of the contents are designed well by topical sequencing or by spiral sequencing. But others have some problems based on topical sequencing and spiral sequencing. Generally, the contents are represented in the order of Perception of phenomena with senses level, Macroscopic understanding level, Understanding of scientific term level, Microscopic understanding level by grade. But the state change contents related to solidification and melting, and conditions of state change contents related to heat, temperature, wind, and humidity are not represented in the level of Microscopic understanding. The contents of state change and conditions related to heat and wind are not represented in the level of scientific term also.

• Journal of The Korean Association For Science Education
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• v.21 no.4
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• pp.677-688
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• 2001

The purposes of this study are to investigate the school science high achievers' achievements in enrichment physics, logical thinking level, and to analyze the relationship between logical thinking level and the achievement in enrichment physics of high achievers in science. The subjects were 357th and 8th graders who achieved highly in school science. To assess their achievements in enrichment physics, we developed a new test consisting of descriptive problems which were based on middle school curriculum. Those problems require one or two steps of thinking process, not simple knowledge of science. To assess logical thinking level, we used the instrument called GALT(Group Assessment of Logical Thinking) developed by Roadranka et al. The results showed that the school science high achievers' average achievement in enrichment physics was low, 56.3 out of 150, which indicated that they had not done much of enrichment learning beyond middle school science curriculum. Just only 54% of the school science high achievers are in formal logical thinking level. From the analysis of relationship between their logical thinking level and the achievement in enrichment physics, the value of the correlation coefficient was 0.174, which means that they are not almost correlated. Therefore, it is not desirable to judge science gifted children just from achievement in school science or enrichment physics, so both(logical thinking and the achievement in enrichment physics) tests should be taken for selecting gifted student.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.671-679
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• 2016

Bridges, which constitute one of the key facilities in a social infrastructure, are easily accessed and used by users, so that keeping their performance above a certain level is essential. According to various cases in the U.S., Japan and Europe with a long construction history, it is expected that the maintenance cost of bridges in Korea will increase continuously in the future, so a rational decision making system based on engineering factors is necessary to optimize the performance of and maintain them by allocating the limited budget efficiently. This study is a preliminary basic study for the purpose of developing a common asset management system for managing all of the bridges and maintaining the level of service provided by them. The scope of this preliminary study is limited to bridges in urban areas. The bridge asset management system for bridges in urban areas, their level of service (LOS) and performance measure (PM) were developed by carrying out a workshop consisting of both experts and stakeholders. The analysis on the weights of the value and performance measure for each performance indicator was carried out by using the multi-attribute utility theory and the AHP method. In order to confirm the application of the weight of the performance measure and value of the performance indicator, six bridges in an example city were selected, LOS analysis was applied and its results were reviewed.