• Education of Primary School Mathematics
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• v.24 no.1
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• pp.21-41
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• 2021

Despite the necessity and significance of mathematical competencies in the 2015 revised mathematics curriculum, there has been lack of studies analyzing textbooks in which such competencies are intended in detail through various tasks. Given this background, this paper analyzed how mathematical competencies and their sub-elements have been represented in the mathematics textbooks for third and fourth grade. The findings of this study showed that 'communication' was the most prevalent mathematical competence, followed by 'reasoning', 'creativity and integration', 'information processing', 'attitude and practice', and 'problem solving' in order. This study also explored the characteristics of mathematical competencies in the textbooks by analyzing which sub-elements per competence were popular. With illustrative examples, this paper is expected to provide for textbook developers with implications on how to represent mathematical competencies throughout the textbooks.

• Journal of Environmental Science International
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• v.32 no.8
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• pp.595-611
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• 2023

The purpose of this study is to improve the daily prediction results of PM2.5 from the air quality diagnosis and evaluation system operated by the Busan Institute of Health and Environment in real time. The air quality diagnosis and evaluation system is based on the photochemical numerical model, CMAQ (Community multiscale air quality modeling system), and includes a 3-day forecast at the end of the model's calculation. The photochemical numerical model basically has limitations because of the uncertainty of input data and simplification of physical and chemical processes. To overcome these limitations, this study applied DNN (Deep Neural Network), a deep learning technique, to the results of the numerical model. As a result of applying DNN, the r of the model was significantly improved. The r value for GFS (Global forecast system) and UM (Unified model) increased from 0.77 to 0.87 and 0.70 to 0.83, respectively. The RMSE (Root mean square error), which indicates the model's error rate, was also significantly improved (GFS: 5.01 to 6.52 ug/m³ , UM: 5.76 to 7.44 ug/m³ ). The prediction results for each concentration grade performed in the field also improved significantly (GFS: 74.4 to 80.1%, UM: 70.0 to 77.9%). In particular, it was confirmed that the improvement effect at the high concentration grade was excellent.

• Steel and Composite Structures
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• v.34 no.5
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• pp.681-698
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• 2020

The paper addresses contribution to the modeling and optimization of major machinability parameters (cutting force, surface roughness, and tool wear) in finish dry hard turning (FDHT) for machinability evaluation of hardened AISI grade die steel D₃ with PVD-TiN coated (Al₂O₃-TiCN) mixed ceramic tool insert. The turning trials are performed based on Taguchi's L₁₈ orthogonal array design of experiments for the development of regression model as well as adequate model prediction by considering tool approach angle, nose radius, cutting speed, feed rate, and depth of cut as major machining parameters. The models or correlations are developed by employing multiple regression analysis (MRA). In addition, statistical technique (response surface methodology) followed by computational approaches (genetic algorithm and particle swarm optimization) have been employed for multiple response optimization. Thereafter, the effectiveness of proposed three (RSM, GA, PSO) optimization techniques are evaluated by confirmation test and subsequently the best optimization results have been used for estimation of energy consumption which includes savings of carbon footprint towards green machining and for tool life estimation followed by cost analysis to justify the economic feasibility of PVD-TiN coated Al₂O₃+TiCN mixed ceramic tool in FDHT operation. Finally, estimation of energy savings, economic analysis, and sustainability assessment are performed by employing carbon footprint analysis, Gilbert approach, and Pugh matrix, respectively. Novelty aspects, the present work: (i) contributes to practical industrial application of finish hard turning for the shaft and die makers to select the optimum cutting conditions in a range of hardness of 45-60 HRC, (ii) demonstrates the replacement of expensive, time-consuming conventional cylindrical grinding process and proposes the alternative of costlier CBN tool by utilizing ceramic tool in hard turning processes considering technological, economical and ecological aspects, which are helpful and efficient from industrial point of view, (iii) provides environment friendliness, cleaner production for machining of hardened steels, (iv) helps to improve the desirable machinability characteristics, and (v) serves as a knowledge for the development of a common language for sustainable manufacturing in both research field and industrial practice.

• Journal of The Korean Association of Information Education
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• v.9 no.4
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• pp.649-659
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• 2005

A window presentation style, either tiled window or single page design, determines the spatial arrangement of information in a modern computer-based instructional design. This study investigates the interaction between spatial ability and window presentation style in terms of student's achievement of cognitive knowledge through Web-based instruction. Seventy-one students from the Falk School in Pennsylvania were pre-tested to determine their level of spatial ability, then randomly divided into two treatment groups in order to study a Web-based instructional unit on flowering plants. The Web-based instructional package was organized with either tiled window presentation or single page presentation. A posttest measured participants'acquisition of the instructional content. Posttest and spatial ability test scores were analyzed using multi-variate linear regression for the full sample (n=71) and three sub-samples: (a) 4th and 5th grade students only, (b) female students only, and (c) 4th and 5th grade female students only. The goals of the data analysis included the examination of (i) the correlation between spatial ability and posttest scores; (ii) the correlation between window presentation style and posttest score; and (iii) the interaction between spatial ability (aptitude) and presentation style (treatment).The data from all four sample groups showed a significant relationship between spatial ability and achievement of cognitive knowledge at the 1% level of significance. The aptitude-treatment interaction between spatial ability and style of window presentation was not significant in the full sample, but was significant in the sub-samples either at the 10% or 5% level. In neither the full sample nor any sub-sample data did window presentation style have an impact on average posttest score. In all analyses, the higher the level of spatial ability, the higher the posttest score. The sub-samples revealed that students with low spatial ability performed better with the tiled window presentation, while those with high spatial ability did better with the single page presentation. Neither window presentation style was shown to better foster learning by children of all levels of spatial ability.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.420-429
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• 2002

The amount of $CO_2$-silicate bonded waste foundry sand(WFS) occurred in Korea is over 800,000 ton per year. WFS, as a by-product, is generated through manufacturing process of foundry may affect our environmental contamination, The reason is that WFS has been buried itself not less than 90％ out of total WFS. So, it can give damage on the ground of contamination in soil and underwater. Therefore, it is necessary to establish the method recycling WFS because of being intensified waste management law. In this study, we performed the research with respect to harmful component analysis, the qualities of WFS mortar and concrete mixed with WFS. As the results the specific gravity of WFS is the same as that of natural aggregate while unit weight and percentage of solids of WFS are smaller than those of it. But it is found that WFS can be used by substituting WFS for natural aggregate after control of poor grade of WFS. The flowability of mortar and concrete with WFS is inferior to those of natural aggregate, and the setting time of concrete with WFS is faster than that with only natural aggregate, On the contrary, the bleeding of concrete with WFS is shown good result, and compressive and tensile strength of concrete substituted WFS for 30％ are higher than those with only natural aggregate regardless of elapsed time.

• The Korean Journal of Pesticide Science
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• v.6 no.1
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• pp.31-35
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• 2002

Objectives of this study were to determine if impurities in technical grade benfuracarb inhibit glutathione-S-transferase and amidase and to identify structures of impurities in technical grade benfuracarb. Technical grade benfuracarb, active ingredient, and impurity inhibited glutathione-S-transferase, and their $I_{50}$ were $9.7{\times}10^{-4}M,\;>1.0{\times}10^{-3}M,\;1.8{\times}10^{-4}M$, respectively. Such inhibition, however, was not higher than that by ethacrynic acid, a selective inhibitor to GST. Technical grade benfuracarb, active ingredient, and impurity also inhibited amidase, and their $I_{50}$ were $6.0{\times}10^{-5}M,\;4.3{\times}10^{-4}M,\;7.6{\times}10^{-5}M$, respectively. Our results show that the inhibition of both detoxifying enzymes by impurities in benfuracarb was 10-fold lower than that by active ingredient, suggesting that both active ingredient and impurities are involved in the inhibition of both detoxifying enzymes. Of four impurities (IM $1{\sim}4$) that were separated from technical grade benfuracarb, IM 2 and IM 3 inhibited GST and amidase. Based on data from IR, $^1H$-NMR, $^{13}C$-NMR and MS, it was determined that IM 2 is ethyl-N-isopropylamino propionate and IM 3 is ethyl-N-isopropyl-N(chlorosulfenyl)aminopropionate.

• Journal of Acupuncture Research
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• v.19 no.6
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• pp.35-48
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• 2002

Objective : The study was performed to evaluate the effect of treatment for thoracolumbar compression fracture by using Bee Venom Acupuncture that is well known for anti-inflammatory and analgesic effect. Methods : We investigated 39 cases of patient with thoracolumbar compression fracture. The patients with thoracolumbar compression fracture were treated at the department of acupuncture & moxibustion of Kyung-Won University Oriental Hospital from 1st January 2001 to 30th August 2002. We selected for two groups. One group was treated by Bee Venom Acupuncture therapy(Bee Venom Acupuncture Group : BAG), the other group was treated by Filiform Acupuncture therapy(None Bee Venom Acupuncture Group : NBAG). Results : 1. The distribution showed female predominance in sex and 70's predominance in age. The largest group was "accidental fall" and the next was "lifting heavy objects" in causes, and within 2 weeks in the duration of disease 2. In the duration of admission, the largest group was within 4 weeks. In regard to level of injury, T12 was found to be most predominant, followed in turn by L1, L2, L5. In regard to grade of clinical symptoms, Grade III was most predominant, followed by Grade II, Grade IV. 3. In the results of treatment, 87.5% were above "Good" in BAG and 47.8% in NBAG. 4. In the result of treatment due to the grade of clinical symptoms, BAG was more excellent than NBAG on the whols grade. 5. In the result of treatment due to duration of admission, the duration of admission was not in proportion to the results of treatment. 6. In the change of lumber flexion, the improvement above $80^{\circ}$ was 50% in BAG and 21.7% in NBAG 7. In the stability of treatment, the BAG and NBAG did't show any detrimental change in GOT, GPT, r-GTP, BUN, creatinine. Conclusions : In the treatment of thoracolumbar compression fracture, the Bee Venom Acupuncture can be regarded as more effective treatment than Filiform Acupuncture in the clinical practice. This is expected to be available for clinical use.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.59-64
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• 2000

We performed refraction, keratometry, slit lamp biomicroscopy. We selected 58 current spherical RGP lens wearers for this three-month study. All patients exhibits at least 0.75D of corneal astigmatism measured with the keratometer, and 37 patients had corneal astigmatism of 1.50D or greater. At least follow-up visit, we measured Snellen acuity with lenses, and performed overrefraction, overkeratometry and slit lamp biomicroscopy. We charted lens position, movement and surface quality. During the three month, biomicroscopy revealed no corneal edema and neovascularization on any patients. Fluorescein staining were 52 patients case of grade 0.5 patients case of grade 1, and 1 patient case of grade 2. In evaluating post-fit residual cylinder, on overrefraction as a percentage of refractive cylinder. By the initial visit, one-week visit, one-month visit, and two-month visit are 41%, 34%, 29%, respectively. In this data, we knew no change after one month. The average overrefraction for these eyes in absolute diopters is 0.26D(initial visit), 0.22D(one-week visit, 0.17D(one-month visit), and 0.16D(two-month visit). The use of a regimen containing a dedicated daily cleaner was more effective in maintaining patient comfort and lens cleanliness than was the use of a regimen containing only a multipurpose solution.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.38-43
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• 2008

The hydroforming technology has been spreaded dramatically in automotive industry last 10 years. Itmay cause many advantages to automotive applications in terms of better structural integrity of the parts, lower cost from fewer part count, material saving, weight reduction, lower springback, improved strength and durability and design flexibility. In this study, the whole process of rear sub-frame parts development by tube hydroforming using steel material having tensile strength of 440MPa grade is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Design) to confirm hydroformability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape in automotive rear sub-frame by hydroforming process were carefully investigated. Overall possibility of hydroformable sub-frame parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending, preforming and hydroforming. In addition, all the components of prototyping tool are designed and interference with press is examined from the point of geometry and thinning.

• Childhood Kidney Diseases
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• v.12 no.1
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• pp.54-61
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• 2008

Purpose: This study was performed to assess necessity of voiding cystourethrography (VCUG) for infants with urinary tract infection (UTI) who had both normal renal sonography and normal DMSA renal scans. Methods: We reviewed 117 infants hospitalized for UTI between February 2002 and July 2007 at Sanggye Paik Hospital. The diagnosis of UTI was made by culture from a urine specimen obtained by suprapubic puncture(n=57), catheterization(n=58), or collection bag method (n=2, twice positive culture of the same organism). All patients had undergone renal sonography, DMSA renal scan and VCUG. Children with both normal renal sonography and normal DMSA renal scans were evaluated for the presence or severity of vesicoureteral reflux (VUR). Results: Of the 117 patients, 96 were boys and 21 were girls. 28 patients(23.9%) had VUR. 59(50.4%) showed both normal renal sonography and normal DMSA renal scans. Among these 59 patients, 7(11.9%) showed VUR. Three of them had grade I-II reflux, two grade III reflux, and the other two grade IV reflux. One of them showed bilateral VUR, grade IV reflux on the right and grade III on the left. Conclusion: Although the negative predictive value of both normal renal sonography and normal DMSA renal scan for VUR was 88.1%, 7 patients had VUR and two of them had high grade reflux(grade IV). So, we suggest that VCUG should be performed in infants with UTI despite both normal renal sonography and normal DMSA renal scans.