• Journal of the Korean Society of Costume
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• v.59 no.6
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• pp.72-81
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• 2009

The purpose of this study is to develop geometric patterns which can be reinterpreted in a modern sense and textile designs which can be commercialized in the mural painting of Goguryeo Dynasty's tomb. Of 42 tombs where genres and portraits could be observed, the costume style of Goguryeo dynasty could be mainly observed in the tombs built in the 4th and 5th centuries. Since geometric patterns found in the portrait could be represented in a modern sense, this study was intended to develop the patterns of a necktie which is one of cultural products by applying geometric patterns in the mural painting of Goguryeo Dynasty's tomb in the 5th century with many patterns distributed. The scope of patterns was limited to a square, a triangle, a circle, and a diagonal line which were the basic of geometric patterns found in the mural painting. The methods of study were literature review and empirical study. Adobe Photoshop CS3 was used to edit geometric patterns found in the mural painting of Goguryeo Dynasty's tomb in the 5th century. By extracting a square(${\square}$), a triangle(${\vartriangle}$), a circle(${\bigcirc}$), and a diagonal line(${\diagdown}$) from edited images, predicted images were proposed before products were made. Finally textile designs were made through the simulation of edited design patterns in the necktie and handkerchief. This study will contribute to the positive effects on the development of cultural product designs applying the characteristic of geometric patterns and the construction of Korean image.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.110-116
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• 2002

At elevated temperature, very complex precipitations occur in STS316. To investigate the effect of the precipitation on mechanical properties in SIS316, tensile tests and fatigue crack growth tests were carried out at $650^{\circ}C$ using artificially degraded materials. The material degradation was simulated by aging for up to 20000 hrs. at $750^{\circ}C$, which is equal to 179000hrs (about 20yrs) of service life at $650^{\circ}C$, after conducting solution treatment for 20 min. at $11300^{\circ}C$. The result of the hardness test and the tensile test showed that both properties are closely related to the mean free distance of carbides. Also, from the results of fracture tests at $650^{\circ}C$, ${\triangle}K_{th}$, after values were found to decrease as aging time and microstructure, as the volume fraction of $\sigma$ phase increased.

• Journal of the Korean Society of Costume
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• v.59 no.3
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• pp.131-144
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• 2009

This study is about single-layered $Chog{\breve{a}}ri$ excavated from SongHyosang(宋效商, 1430-1490, SHS hereafter), SongHeeJong(宋喜從, the late 1500s, SHJ hereafter) tombs. There are 7 single-layered $Chog{\breve{a}}ris$ for men. We focus on comparison of their design and sowing method. 1. Design: Investigating collar, $Chog{\breve{a}}ris$ from SHS have MokpanGit and $Chog{\breve{a}}ris$ from SHJ have KalGit. KalGit has been seen from SHJ to 17th, 18th and 19th centuries. After the late 1500s, there is no MokpanGit single-laTered $Chog{\breve{a}}ri$ for men. Side panel under arm has various shapes(triangle, trapezoid, triangle+trapezoid) in 15th century. After the late 1500s, It changes into no side panel. Two $Chog{\breve{a}}ris$ with no side panel from SHJ reveals that the late 1500s is a period of transition. 2. Sewing method: First, researching lengthwise grainline of the fly, the left fly has lengthwise grainline outside In four, inside in three. The right fly has lengthwise grainline outside in just one, the others have lengthwise grainline inside. Compared with today's way, there is a great difference, but in those times there isn't an established rule. This is true of side panel under arm. The sewing method are backstitch, running stitch, and hemming. Researching the construction method of seam, in putting two selvages together, open seam and plain seam are used. In putting selvage and bias, bias and bias together, flat felled seam and french seam are used. This study shows that single-layered $Chog{\breve{a}}ri$ far men from 15C. to 16C. has changes of design such as collar(Git) and side panel undo. arm. But there is little change in sewing method.

• Journal of Educational Research in Mathematics
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• v.25 no.3
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• pp.461-472
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• 2015

Korean students are taught area formulas of parallelogram and triangle by inductive reasoning in current curriculum. Inductive thinking is a crucial goal in mathematics education. There are, however, many problems to understand area formula inductively. In this study, those problems are illuminated theoretically and investigated in the class of 5th graders. One way to teach area formulas is suggested by means of process of problem solving with transforming figures.

• Industrial Engineering and Management Systems
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• v.4 no.2
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• pp.192-197
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• 2005

Among many amplitude parameters, Kurtosis (4-th normalized moment of probability density function) is recognized to be the sensitive good parameter for machine diagnosis. Kurtosis has a value of 3.0 under normal condition and the value generally goes up as the deterioration proceeds. In this paper, simplified calculation method of kurtosis is introduced for the analysis of impact vibration with one sided affiliated impact vibration which occurs towards the progress of time. That phenomenon is often watched in the failure of such as bearings’ outer race. One sided affiliated impact vibration is approximated by one sided triangle towards the progress of time and simplified calculation method is introduced. Varying the shape of one sided triangle, various models are examined and it is proved that new index is a sensitive good index for machine failure diagnosis. Utilizing this method, the behavior of kurtosis is forecasted and analyzed while watching machine condition and correct diagnosis is executed.

• Education of Primary School Mathematics
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• v.20 no.4
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• pp.305-319
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• 2017

In the process of finding the triangle height, 26 students in the 6th grade were surveyed to understand the students' triangle height through the eye movement data and to investigate the cognitive load of the students. As a result, the correctness rate of the pre-test was significantly increased in the post-test, and the frequency and retention of gaze data were smaller in the post-test than in the AOI of each question. The Participants's subjective cognitive load indicated that it was more difficult to understand the concept of rotated triangles compared with upright triangles that were parallel to the ground. More frequent and more retentions in the eye-tracking data were detected in the right triangles and acute triangles by rotating configuration. Eye movement data show that eye tracking technology can provide an objective measure of students' cognitive load for feedback on instructional design.

• Asian review of World Histories
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• v.2 no.2
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• pp.197-216
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• 2014

This paper examines A. G. Frank's views about 15th-19th Korea (Joseon Dynasty) in his Reorient. A. G. Frank recognized that Korea might have played a great role in the international relations of East Asia, but he did not write systematically about it and he did not treat Korea as an independent player in the history of East Asia. I think the greatest limitation to his re-interpretation of East Asia is in that he depends too much on China's and Japan's perspective. In order to overcome Frank's shortcomings regarding the history of Korea, first I examine what Frank recognized about the Joseon dynasty between 1400 and 1800. Next I compare Joseon's development to that of China and Japan between 1400 and 1800. Frank compared Europe and East Asia (mainly China and Japan) from three aspects of quantities (population, production, productivity, and trade), qualities (science and technology), and mechanism (economic and financial institutions). With this research we insist that Joseon should not be dismissed in 15th-19th East Asia. The reasons are as follows. First, Joseon between 1400 and 1800 had developed economically as much as China and Japan. Second, Joseon had played a great role in connecting China and Japan and had a positive influence on the development of Japan. So we need to reappraise Reorient's view about East Asia. Only when role of Joseon can be correctly estimated, the dynamics and diversity of East Asia can be properly understood.

• Journal of the Korea Convergence Society
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• v.8 no.7
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• pp.15-21
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• 2017

Recently, users' interest in IoT related products is increasing as the 4th industrial revolution has become social. The types and functions of sensors used in IoT devices are becoming increasingly diverse, and mutual authentication technology of IoT devices is required. In this paper, we propose an efficient double signature authentication scheme using Pascal's triangle theory so that different types of IoT devices can operate smoothly with each other. The proposed scheme divides the authentication path between IoT devices into two (main path and auxiliary path) to guarantee authentication and integrity of the IoT device. In addition, the proposed scheme is suitable for IoT devices that require a small capacity because they generate keys so that additional encryption algorithms are unnecessary when authenticating IoT devices. As a result of the performance evaluation, the delay time of the IoT device is improved by 6.9% and the overhead is 11.1% lower than that of the existing technique. The throughput of IoT devices was improved by an average of 12.5% over the existing techniques.

• Journal of Science Education
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• v.41 no.3
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• pp.480-498
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• 2017

This study analyzed the errors of 6th graders of elementary school in problem solving process of the measurement domain. By analyzing the errors that students make in solving difficult problems, this study tried to draw implications for teaching and learning that can help students reach their achievement standards. First, though the students were given enough time to deal with problems, the fact that about 30~60% of students, based upon the problems given, can't solve them show that they are struggling with a part of measurement domain. Second, it was confirmed that students' understanding of the unit of measurement, such as relationship between units, was low. Third, the students have a low understanding in terms of the fact that once the base is set in a triangle then the height can be set accordingly and from which multiple expressions, in obtaining the area of the triangle, can be driven.

• Journal of Educational Research in Mathematics
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• v.21 no.2
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• pp.181-199
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• 2011

The area formula for a plane figure represents the relations between the area and the lengths which determine the area of the figure. Students are supposed to understand the relations in it as well as to be able to find the area of a figure using the formula. This study investigates how 5th grade students understand the formulas for the area of triangle, rectangle and parallelogram, focusing on their understanding of functional relations in the formulas. The results show that students have insufficient understanding of the relations in the area formula, especially in the formula for the area of a triangle. Solving the problems assigned to them, students developed three types of strategies: Substituting numbers in the area formula, drawing and transforming figures, reasoning based on the relations between the variables in the formula. Substituting numbers in the formula and drawing and transforming figures were the preferred strategies of students. Only a few students tried to solve the problems by reasoning based on the relations between the variables in the formula. Only a few students were able to aware of the proportional relations between the area and the base, or the area and the height and no one was aware of the inverse relation between the base and the height.