• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.487-494
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• 2005

Nowadays a large amount of wastewater containing metal working fluids and cleaning agents is generated during the cleaning process of parts working in various industries of automobile, machine and metal, and electronics etc. In this study, aqueous or semi-aqueous cleaning wastewater contaminated with soluble or nonsoluble oils was treated using ultrafiltration system. And the membrane permeability flux and performance of oil-water separation (or COD removal efficiency) of the ultrafiltration system employing PAN as its membrane material were measured at various operating conditions with change of membrane pore sizes and soil concentrations of wastewater and examined their suitability for wastewater treatment contaminated with soluble or insoluble oil. As a result, in case of wastewater contaminated with soluble oil and aqueous or semi-aqueous cleaning agent, the membrane permeability increased rapidly even though COD removal efficiency was almost constant as 90 or 95％ as the membrane pore size increased from 10 kDa to 100 kDa. However, in case of the wastewater contaminated with nonsoluble oil and aqueous or semi-aqueous cleaning agent, as the membrane pore size increased from 10 kDa to 100 kDa and the soil concentration of wastewater increased, the membrane permeability was reduced rapidly while COD removal efficiency was almost constant. These phenomena explain that since the membrane material is hydrophilic PAN material, it blocks nonsoluble oil and reduces membrane permeability. Thus, it can be concluded that the aqueous or semi-aqueous cleaning solution contaminated with soluble oil can be treated by ultrafiltration system with the membrane of PAN material and its pore size of 100 kDa. Based on these basic experimental results, a pilot plant facility of ultrafiltration system with PAN material and 100 kDa pore size was designed, installed and operated in order to treat and recycle alkaline cleaning solution contaminated with deep drawing oil. As a result of its field application, the ultrafiltration system was able to separate aqueous cleaning solution and soluble oil effectively, and recycle them. Further more, it can increase life span of aqueous cleaning solution 12 times compared with the previous process.

• Journal of The Korean Association For Science Education
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• v.35 no.6
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• pp.985-995
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• 2015

This study examines the effects of the introduction of artistic and technological factors on science problems for the activation of creative and integrated thinking. We developed problems consisting of STA(problems that introduced technological and artistic factors on the College Scholastic Ability Test) and TA(problems that introduced artistic factors in a technological context). Subjects of the study included 60 high school senior students in Daegu. Their problem solving processes for STA were examined. Four students were interviewed using the retrospective interview method. Also, after finishing TA, the problem solving processes of four students were examined. The results of the study are as follows. First, students selected scientific context more than artistic and technological contexts. It was found that students preferred short length problem in order to solve problems in a short time. Second, students were more interested in artistic and technological contexts of STA than scientific context, but felt that they were more difficult. Moreover, students were more interested about the context of TA than scientific context. Third, irrespective of the given contexts in STA, students have a tendency to solve problems through relatively brief ways by using core scientific knowledge. This can seem to mean that there is a possibility to stereotype the problem solving process through repeated learning. Logical thinking and elaboration were observed, but creativity was not conspicuous. In addition, integrated thinking was not observed in all contexts of STA. Fourth, science related problems of TA showed similar results. However, in problems related to everyday life, students made original descriptions that they based on their daily lives. Particularly, in creative design, original ideas and integrated thinking were observed.

• Journal of Environmental Impact Assessment
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• v.24 no.6
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• pp.607-618
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• 2015

Five years have passed since the first set of environmental samples was taken in 2011 to represent various ecosystems which would help future generations lead back to the past environment. Those samples have been preserved cryogenically in the National Environmental Specimen Bank(NESB) at the National Institute of Environmental Research. Even though there is a strict regulation (SOP, standard operating procedure) that rules over the whole sampling procedure to ensure each sample to represent the sampling area, it has not been put to the test for the validation. The question needs to be answered to clear any doubts on the representativeness and the quality of the samples. In order to address the question and ensure the sampling practice set in the SOP, many steps to the measurement of the sample, that is, from sampling in the field and the chemical analysis in the lab are broken down to evaluate the uncertainty at each level. Of the 8 species currently taken for the cryogenic preservation in the NESB, pine tree samples from two different sites were selected for this study. Duplicate samples were taken from each site according to the sampling protocol followed by the duplicate analyses which were carried out for each discrete sample. The uncertainties were evaluated by Robust ANOVA; two levels of uncertainty, one is the uncertainty from the sampling practice, and the other from the analytical process, were then compiled to give the measurement uncertainty on a measured concentration of the measurand. As a result, it was confirmed that it is the sampling practice not the analytical process that accounts for the most of the measurement uncertainty. Based on the top-down approach for the measurement uncertainty, the efficient way to ensure the representativeness of the sample was to increase the quantity of each discrete sample for the making of a composite sample, than to increase the number of the discrete samples across the site. Furthermore, the cost-effective approach to enhance the confidence level on the measurement can be expected from the efforts to lower the sampling uncertainty, not the analytical uncertainty. To test the representativeness of a composite sample of a sampling area, the variance within the site should be less than the difference from duplicate sampling. For that, a criterion, ${i.e.s^2}_{geochem}$(across the site variance) <${s^2}_{samp}$(variance at the sampling location) was proposed. In light of the criterion, the two representative samples for the two study areas passed the requirement. In contrast, whenever the variance of among the sampling locations (i.e. across the site) is larger than the sampling variance, more sampling increments need to be added within the sampling area until the requirement for the representativeness is achieved.

• Journal of Gifted/Talented Education
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• v.22 no.3
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• pp.619-637
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• 2012

The purpose of this study is to develop a new program for elementary math-gifted students by using 'Girih Tililng' and apply it to the elementary students to improve their math-ability. Girih Tililng is well known for 'the secrets of mathematics hidden in Mosque decoration' with lots of recent attention from the world. The process of this study is as follows; (1) Reference research has been done for various tiling theories and the theories have been utilized for making this study applicable. (2) The characteristic features of Mosque tiles and their basic structures have been analyzed. After logical examination of the patterns, their mathematic attributes have been found out. (3) After development of Girih tiling program, the program has been applied to math-gifted students and the program has been modified and complemented. This program which has been developed for math-gifted students is called 'Exploring the Secrets of Girih Hidden in Mosque Patterns'. The program was based on the Renzulli's three-part in-depth learning. The first part of the in-depth learning activity, as a research stage, is designed to examine Islamic patterns in various ways and get the gifted students to understand and have them motivated to learn the concept of the tiling, understanding the characteristics of Islamic patterns, investigating Islamic design, and experiencing the Girih tiles. The second part of the in-depth learning activity, as a discovery stage, is focused on investigating the mathematical features of the Girih tile, comparing Girih tiled patterns with non-Girih tiled ones, investigating the mathematical characteristics of the five Girih tiles, and filling out the blank of Islamic patterns. The third part of the in-depth learning activity, as an inquiry or a creative stage, is planned to show the students' mathematical creativity by thinking over different types of Girih tiling, making the students' own tile patterns, presenting artifacts and reflecting over production process. This program was applied to 6 students who were enrolled in an unified(math and science) gifted class of D elementary school in Daejeon. After analyzing the results produced by its application, the program was modified and complemented repeatedly. It is expected that this program and its materials used in this study will guide a direction of how to develop methodical materials for math-gifted education in elementary schools. This program is originally developed for gifted education in elementary schools, but for further study, it is hoped that this study and the program will be also utilized in the field of math-gifted or unified gifted education in secondary schools in connection with 'Penrose Tiling' or material of 'quasi-crystal'.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.6
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• pp.13-25
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• 2016

This study aims to analyze the change process in order to set the improvement strategies for the zoo in the Seoul Children's Grand Park. The zoo can be reviewed through three significant time periods with noticeable changes. As a framework to analyze the major changes that happened in the zoo, this study looks at the changes in terms of the planning aspect as well as the animal welfare and program operation aspect. The findings are as follows: first, the era of general theme park turned out to have focused on exhibiting animals to meet visitor demands by expanding the zoo area of the zoo without enlarging stockyards for the animals. Second, the environmental park era created a zoo having entertaining and educational functions by arranging animal houses with the concept of zoological taxonomy and introducing animal behavioral enrichment, animal welfare programs and visitor participatory programs. The era of the zoo as an Urban Cultural Park improved old animal houses and facilities for the welfare of the animals and increased educational programs to preserve species and provide environmental education. The current status of the zoo turns out not to meet the conditions for creating an ecological zoo, which is the overall goal for contemporary zoos. The improvement strategies based on the analysis through three different eras are three-fold. First, the zoo needs to improve the boundary conditions of the animals to showcase animal wildness through landscape immersion. Second, the zoo should provide a shared environment for animals from the same habitats by changing the classification methods from the existing polyphyletic taxon to a classification that considers ecological habitat. Third, the zoo needs to develop various ecological education programs by supplementing specialists in professional education.

• Korean Journal of Optics and Photonics
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• v.16 no.3
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• pp.182-190
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• 2005

The fiber Raman amplifier(FRA) is a distinctly advantageous technology. Due to its wider, flexible gain bandwidth, and intrinsically lower noise characteristics, FRA has become an indispensable technology of today. Various FRA modeling methods, with different levels of convergence speed and accuracy, have been proposed in order to gain valuable insights for the FRA dynamics and optimum design before real implementation. Still, all these approaches share the common platform of coupled ordinary differential equations(ODE) for the Raman equation set that must be solved along the long length of fiber propagation axis. The ODE platform has classically set the bar for achievable convergence speed, resulting exhaustive calculation efforts. In this work, we propose an alternative, highly efficient framework for FRA analysis. In treating the Raman gain as the perturbation factor in an adiabatic process, we achieved implementation of the algorithm by deriving a recursive relation for the integrals of power inside fiber with the effective length and by constructing a matrix formalism for the solution of the given FRA problem. Finally, by adiabatically turning on the Raman process in the fiber as increasing the order of iterations, the FRA solution can be obtained along the iteration axis for the whole length of fiber rather than along the fiber propagation axis, enabling faster convergence speed, at the equivalent accuracy achievable with the methods based on coupled ODEs. Performance comparison in all co-, counter-, bi-directionally pumped multi-channel FRA shows more than 102 times faster with the convergence speed of the Average power method at the same level of accuracy(relative deviation < 0.03dB).

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.6
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• pp.18-28
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• 2015

The purpose of this study is to develop a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were performed on one unreinforced beam-column specimen and two reinforced specimens with U-type precast wall panels. The results were analyzed to find that the specimen with anchored connection experienced shear failure, while the other specimen with steel plate connection principally manifested flexural failure. The ultimate strength of the specimens was determined to be the weaker of the shear strength of top connection and flexural strength at the critical section of precast panel. In this setup of U-type panel specimens, if a push loading is applied to the reinforced concrete column on one side and push the precast concrete panel, a pull loading from upper shear connection is to be applied to the other side of the top shear connection of precast panel. Since the composite flexural behavior of the two members govern the total behavior during the push loading process, the ultimate horizontal resistance of this specimen was not directly influenced by shear strength at the top connection of precast panel. However, the RC column and PC wall panel member mainly exhibited non-composite behavior during the pull loading process. The ultimate horizontal resistance was directly influenced by the shear strength of top connection because the pull loading from the beam applied directly to the upper shear connection. The analytical result for the internal shear resistance at the connection pursuant to the anchor shear design of ACI 318M-11 Appendix-D, agreed with the experimental result based on the elastic analysis of Midas-Zen by using the largest loading from experiment.

• Journal of The Korean Association For Science Education
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• v.31 no.1
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• pp.78-98
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• 2011

The purpose of this study was to analyze elementary school students' interpretation of data characteristics by cognitive style. Participants were elementary students in sixth grade who can use integrated inquiry process skills. The students were divided into two groups, analytic cognitive style and wholistic cognitive style according to their response to Cognitive Style Analysis. They performed scientific interpretation of data activity. To collect data for this study, participants recorded the result on scientific interpretation of data activity paper and researcher recorded the situation on videotape and interviewed with participants after the end of interpretation of data to get additional data. And the findings of this study were as follows: First, the study analyzed interpretation of data characteristics by the operator regarding different situations of interpreting data according to cognitive style. For example, in the intermediate state, analytic-cognitive style students showed high achievement in identifying variables, and wholistic-cognitive style students were active in using prior knowledge to interpret data. Second, the result of analysis on the direction of interpreting data and preference for data types in interpreting data activities according to cognitive style are as follows: Wholistic-cognitive style students showed relatively high perception of information through the top-down approach. On the other hand, analytic-cognitive style students usually used the bottom-up approach gradually expanding detailed information to the scientific question-related answer and showed a preference data of the table type. Through the result, this study aimed to help establish a data interpretation strategy for learners to solve problems based on understanding of interpretation of data characteristics according to learners' cognitive style, and purposed the instruction design suggesting the data requiring various data interpretation strategies to develop learners' data interpretation ability.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.4
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• pp.21-35
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• 2018

In recent years, there has been a tendency to reuse 'landscapes of memory,' including industrial heritages, modern cultural heritages, and post-industrial parks, as public spaces in many cities. Among the various types of landscapes, 'modern historic landscapes', which were formed in the 19th and 20th centuries, are landscapes where the debate between conservation and removal is most frequent, according to the change of evaluation and recognition of modern history. This study examines conflicts between conservation and removal around modern historic landscapes and explores the value judgment criteria and the process of formation of those landscapes, as highlighted in the case of the demolition controversy of the old Japanese general government building in Seoul, which was dismantled in 1995. First, this study reviews newspaper articles, television news and debate programs from 1980-1999 and some articles related to the controversy of the Japanese general government building. Then it draws the following six factors as the main issues of the demolition controversy of the building: symbolic location, discoveries and responses of new historical facts, reaction and intervention of a related country, financial conditions, function and usage of the landscape, changes of urban, historical and architectural policies. Based on these issues, this study examines the conflicts between symbolic values that play an important role in the formation of modern historic landscapes and determines conservation or removal, and the utility of functional values that solve the problems and respond to criticisms that arise in the process of forming the modern historic landscape. Especially, it is noted that the most important factor that makes the decision is the symbolic values, although the determination of the conservation or removal of modern historic landscapes has changed according to changes in historical perceptions of modern history. Today, the modern historic landscape is an important site for urban design, and still has historical issues to be agreed upon and addressed. Thi study has contemporary significance from the point that it divides the many values of modern historic landscapes into symbolic values and functional values, evaluates these, and reviews the background social context.

• Journal of Family Resource Management and Policy Review
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• v.25 no.3
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• pp.87-102
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• 2021

Child abuse and neglect are recently increasing in Korea, and although the government has actively improved the child protection system, the number of abused children and the rate of cases judged as abuse have continuously risen. Given that 75% of child abusers are parents, child abuse and neglect are expected to recur. To prevent such a recurrence, various intervention programs for abused children and their parents are required. The purpose of this study were to design a recovery support service process and investigate the effectiveness of pilot program for families of origin, including neglected(protected) children, to improve the system by which these programs are operated, and formulate policy alternatives that reinforce "family preservation" principles. The pilot program was implemented from June to November 2020 in 4-local healthy family support center. The number of program participants and the frequency of participation in each other differed, because of the difference in number of confirmed coronavirus cases in each region and the requirement for social distancing. Through the program, a community-based service process was developed for neglected(protected) children and their parents, and cooperative networks between related facilities and institutions were established. The study formulated the following recommendations: First, a cooperation system among government departments mandated to provide different services to neglected(protected) children is needed. Second, wider and various channels through which abused children can avail of protective services should be developed within communities. Third, more stable environments for program operation should be cultivated, and cooperative partnerships should be sought for knowledge sharing among relevant government departments. Another necessary measure is for a center to develop its own business model, in which the duplication of services provided by involved organizations is avoided. Finally, clear guidelines, administrative standards, and specific plans for program operation should be arranged. Also regional characteristics are maintained, but services should be standardized.