• Journal of Educational Research in Mathematics
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• v.24 no.2
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• pp.205-225
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• 2014

This study analyzed how two sixth graders recognized, generalized, and represented functional relationships in exploring geometric growing patterns. The results showed that at first the students had a tendency to solve the given problem using the picture in it, but later attempted to generalize the functional relationships in exploring subsequent items. The students also represented the patterns with their own methods, which in turn had an impact on the process of generalizing and applying the patterns to a related context. Given these results, this paper includes issues and implications on how to foster functional thinking ability at the elementary school.

• Education of Primary School Mathematics
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• v.26 no.1
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• pp.45-63
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• 2023

The activity of finding rules is useful for enhancing the algebraic thinking of elementary school students. This study analyzed the pattern activities of a finding rules unit in 10 different government-authorized mathematics curricular materials for fourth graders aligned to the 2015 revised national mathematics curriculum. The analytic elements included three main activities: (a) activities of analyzing the structure of patterns, (b) activities of finding a specific term by finding a rule, and (c) activities of representing the rule. The three activities were mainly presented regarding growing numeric patterns, growing geometric patterns, and computational patterns. The activities of analyzing the structure of patterns were presented when dealing mainly with growing geometric patterns and focused on finding the number of models constituting the pattern. The activities of finding a specific term by finding a rule were evenly presented across the three patterns and the specific term tended to be close to the terms presented in the given task. The activities of representing the rule usually encouraged students to talk about or write down the rule using their own words. Based on the results of these analyses, this study provides specific implications on how to develop subsequent mathematics curricular materials regarding pattern activities to enhance elementary school students' algebraic thinking.

• The Mathematical Education
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• v.62 no.2
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• pp.175-194
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• 2023

Despite the importance of pattern learning for elementary school students, few studies have investigated in detail the understanding of patterns of lower-grade students. This study aimed to analyze the understanding of patterns of second-grade elementary school students. Since the patterns in the second grade are taught through the unit called Finding Rules, students' understanding of patterns was compared and contrasted before and after they learned the unit. To this end, a written instrument to measure students' understanding of patterns was developed on the basis of previous studies on pattern learning for lower-grade students. A total of 189 students were analyzed. As a result of the study, the overall correct answer rates in the post-test were higher in most items than those in the pre-test, illustrating the positive effect of the specific unit. However, students found it difficult to find rules in which two components would change simultaneously either in geometric or numeric patterns, find patterns that would be similar in structure, represent geometric patterns into numeric patterns, find empty terms in increasing patterns, and reason the specific terms in patterns that can be differently interpreted. Based on these research results, this study sheds light on students' understanding of patterns and suggests implications to improve their understanding.

• Communications of Mathematical Education
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• v.37 no.4
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• pp.697-715
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• 2023

The purpose of this study is to investigate the overall understanding of patterns by second- and third-grade elementary school students. For this purpose, 12 classes per grade were selected from 10 schools, and a 46-item test was administered to 216 second graders and 223 third graders. The results of the study showed that in most cases, there was no statistically significant difference in the understanding of patterns between second- and third-graders. The exception occurred regarding the 10 items of identifying the structure of a pattern: Second-graders did better than third-graders regarding 8 items, whereas vice versa regarding 2 items. The items that both second- and third-graders struggled with included finding multiple components of a given pattern, comparing the structures between patterns, and guessing a particular term in an open pattern. Based on these findings, this paper discusses second- and third-graders' understanding of patterns and suggestions for further instruction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.561-569
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• 2012

To evaluate the bacteriological water quality in Yongnam-Gwangdo, located in western Jinhae Bay, seawater samples were analyzed using sanitary indicator bacteria at 57 sampling stations. According to survey results from January 2007 to December 2009, the range of the geometric mean and the estimated 90th percentile for coliforms and fecal coliforms in the samples were <1.8-16.5 and 1.8-246.8 MPN/100 mL and <1.8-7.1 and 1.8-74.8 MPN/100 mL, respectively. The samples, including those taken from stations located in Wonmunman, Gwangdo, and Dangdong, showed high levels of microbial contamination caused by the climate and weather patterns in the marine environment. The bacteriological water quality in the area met Korean criteria for a designated shellfish growing area for export and National Shellfish Sanitation Program criteria for an approved shellfish growing area, except at station #49. A total of 24 direct pollution sources were discharged into the shellfish growing area. The radius of impact was calculated for each pollution source to assess the effect on the shellfish growing area. The calculated radius of impact for most of the pollution sources was below 300 m. However, the radius of impact for the combined pollution sources in Kyeonnaeryang was 93-1973 m. There were significant differences between the calculated closed sea area and actual monitoring results. The closed sea area values calculated from the fecal coliform load in drainage water tended to be higher than the actual monitoring results. Tidal currents and environmental factors such as salinity, water temperature, sunlight, and microbiological factors affect the survival of fecal indicator bacteria in seawater.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.3
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• pp.11-20
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• 2022

Currently, the black-white QR (Quick Response) codes have been used widely in consumer advertising fields and the study of color QR codes have received a growing demand because of much higher data encoding capacity. Color QR codes can be reproduced by the printing and scanning processes, however, these encounter colors distortion caused by insufficient lighting, low resolution of camera and geometric deformation during the capturing processes. In order to overcome these problems, this paper proposes an efficient decoding algorithm for color QR codes with inserted patterns, which are dealt with conventional studies. These are evaluated in view of the recognition rate under different noise conditions, for example, Gaussian noises/blurring and geometric deformation. Experimental results demonstrate that the color QR codes with simple pattern can resist the distortion of Gaussian noises/blurrings.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.211-217
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• 2006

Growing urban areas modify patterns of local land use and land cover. Land use changes associated with urban expansion. One way to understand and document land use change and urbanization is to establish benchmark maps compiled from satellite imagery. Old satellite Imagery is useful data to extract urban information. CORONA is a photo satellite reconnaissance program used from 1960 to 1972 and its imagery was declassified and has been available to the public since 1995. Since CORONA images are collected with panoramic cameras, several types of geometric distortions are involved. In this study we proposed mathematical modeling method which use modified collinearity equations. After the geometric modeling, we mosaicked images. We can successfully extract urban boundaries using GLCM method and visual interpretation in CORONA (1972) and SPOT (1995) imagery and detect urban changes in Seoul quantitatively.

• Geomechanics and Engineering
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• v.15 no.3
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• pp.869-877
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• 2018

The continually growing demand for underground space in dense urban cities is also driving the demand for underground highways. Building the underground highway tunnel, however, can involve complex design and construction considerations, particularly when there exists divergence or convergence in the tunnel. In this study, interaction between two asymmetric noncircular tunnels-that is, a larger main tunnel and a smaller tunnel diverging from the main tunnel, was investigated by examining the distributions of the principal stresses and the strength/stress ratio for varying geometric conditions between the two tunnels depending on diverging conditions using both numerical analysis and scale model test. The results of numerical analysis indicated that for the $0^{\circ}$, $30^{\circ}$, $60^{\circ}$ diverging directions, the major principal stress showed an initial gradual decrease and then a little steeper increase with the increased distance from the left main tunnel, except for $90^{\circ}$ where a continuous drop occurred, whereas the minor principal stress exhibited an opposite trend with the major principal stresses. The strength/stress ratio showed generally a bell-shaped but little skewed to left distribution over the distance increased from the left larger tunnel, similarly to the variation of the minor principal stress. For the inter-tunnel distance less than 0.5D, the lowest strength/stress ratio values were shown to be below 1.0 for all diverging directions ($0^{\circ}$, $30^{\circ}$, $60^{\circ}$ and $90^{\circ}$). The failure patterns observed from the model test were found to be reasonably consistent with the results of numerical analysis.

• Journal of the Korean Society of Costume
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• v.6
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• pp.65-87
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• 1982

1. Purpose: The purpose is to apply and adapt ancient textile pattern to practical life, and to contribute to the promotion of the creative development of modernization and Koreanization of textile pattern by the survey of the extent of taste for the textile pattern existent in Korean costume among costumes. 2. Hypothesis: Textile pattern is in most classical one expressed in fact, but nowadays abstract or geometric one is more exist. Consumers are in most part in forties, and so the taste cannot be ignored. Therefore aesthetic consciousness found Korean costume is more important rather than excessively bold or mordern one. 3. Method and Process: (1) This research is analysed 386 one through college student and parents of a primary or high school. (2) Taste of the pattern is comparisoned and analyzed as age. education, pocket money of the student or an income of a month in home through computer. And the analysis of the statistics research is operation through the Chi-Square Goodness of-Fit-Test. 4. Conclusion: (1) The Korean costume put on mostly party or formal dress, therefore it should be researched as an outdoor dress with traditional costume. (2) The most one is concerned in textile pattern, it's taste is different from color, constitution. Textile industry is developed not only weave pattern, gold-coverning pattern but embroidry pattern, dye pattern, therefore the various side of pattern design should be researched. (3) In Side of form, plant pattern is not only most various but highest in popularity. According to approach nowadays, all of the pattern becomes composition or geometric one with abstract tendency and so from these day pattern is necessary combinationed, researched with our people emotion. (4) The color of textile pattern is choiced individual taste. Through investige, research in various side of the modern taste and our costume, we take growing interest in the color, composition of textile, and should dressed with beauty and grace. (5) In side of size, textile pattern is choiced to individual face and body shape through research on form, color, size of these pattern, we should endeavor to dress well. (6) In side of application, most people is concerned in not only interior ornament but the costume is high. Costume research by some people of the outside and symbol with interior through the pattern analysis is not only very important but also is due to people culture.