• Journal of the Korean School Mathematics Society
• /
• v.2 no.1
• /
• pp.121-131
• /
• 1999

Recently our educational methodologies have been changed to an open, student-centered structure. Mathematics is now learned through experiential interaction and less emphasis is placed on abstract theories. For example, the axioms of the geometry in the middle school curriculum have been expressed by using symbolic letters. Students find these abstractions very difficult and it hinders their ability to grasp the significance of geometrical concepts. In an effort to simplify these abstract concepts and enhance the students interest and ability to learn, the GSP (Geometry Sketchpad) is proving to be a useful and effective tool. First, Second and third grade students have found the GSP to be extremely useful. While the pad has no sound function it still enables the students to freely change diagrams without disrupting the integrity of the program. There is also a running order of instructions at the bottom of the screen to facilitate the step by step understanding of mathematical procedures. This function makes the program ideal for use by teachers, students and even beginners. Anyone experiencing difficulty can get immediate assistance from the guidebook which is located at the back of each program. Allowing individuals to manipulate and actually see the changing deductions and axiom proofs on the computer screen provides them with immediate feedback and reinforcement. It also enhances their overall interest in learning geometry. The use of the GSP is proving to be an innovative and effective tool in facilitating the transition of mathematics into an open, student-centered educational forum.

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 2002.06a
• /
• pp.239-247
• /
• 2002

With the introduction of the 7th Curriculum, it has been put greater emphasis on learning by experience. This study aims to implement the quiz-based wireless application for helping to learn more effectively what one will see and hear on the spot when he visits the cultural assets. The materials about Busuk Temple, used as the example of the quiz-based assisted learning, were collected from the libraries and through the internet. And they were programmed using the basic components and properties of WML and then operated with UP SDK 4.0, Phone.com WAP development toolkit. This wireless application makes the user know if it is correct when he selects either O or X as the answer of each question, and shows the individual score after solving 10 questions in total. Each user can also have additional chances to solve them again, even though they doesn't influence the previous score. This study is focused on the implementation of the wireless application for assisted learning by a mobile phone which almost everybody will possess. Various kinds of wireless contents are expected to be developed and provided in the field of education.

• Current Photovoltaic Research
• /
• v.1 no.1
• /
• pp.11-16
• /
• 2013

The current solar cell industry is experiencing a temporary plateau due to a sluggish economy and oversupply. It is expected that the solar industry can see similar growth to that of the recent past by overcoming the current situation, as there is growing demand globally for solar energy. The current situation led to restructuring of the world's solar industry, and domestic firms will need to have competitiveness through strategic approaches and proprietary technology to survive in the global solar market. Crystalline and amorphous silicon based solar cells have led the solar industry and occupied half or more of the market thus far. They will do so in the future PV market as well by playing a pivotal role in the solar industry. In this paper, the current status and prospects of silicon based solar cells, from materials to comprehensive and high efficiency technology that can emerge in the future, are discussed.

• Journal of Digital Convergence
• /
• v.11 no.10
• /
• pp.689-694
• /
• 2013

Craft culture industry 'crafts and culture made up of industry meaning of' rather than 'as a craft industry'. Culture it is desirable to see Roy. Craft culture industry features, technology, techniques, or by indigenous raw materials to the foundation, which is produced as a plastic product manufacturing process, characteristics of the main part of the craft industry with a means to manufacture products. Historically, over the years, which has been formed by tradition, culture, crafts related to specific industries. Only by looking at the craft cultural industries have unique features and understand the value and no longer making craft activity does not remain only in the dimensions of the production, distribution and development of craft industries and national and ethnic culture has inherited expression traditionality a representative craft, culture as a development plan for the industry through the development of market research is to propose ways.

• Journal of architectural history
• /
• v.19 no.6
• /
• pp.23-38
• /
• 2010

This Hee Kyeong Ru, a kind of "Nu-Gak" in Gwangju is a high storied old government official building memorizes the recovery of Gwangju area reputation. Hee Kyeong Ru, literally means, delightful and happy occasions. This kind of the buildings were build for the receptions and the banquets for the high government officials in travelling areas to areas. It provided very high formality as compared to the buildings in the mountains. Nu-Gak buildings have a lot in common, since they had been constructed under the influence of the then time period and for the common reasons. Several records about Hee Kyeong Ru can be found in the old literatures, poetries, pictures and atlases. Also, we can see the shape of the building and the location through the mark in the old map. According to the historic materials, Nu-Gak buildingsof other old goveenment offices with Hee Kyeong Ru are similar to that of the size and construction. So we can draw the common points of the existing old official buildings and could assume the original form of Hee Kyeong Ru. In conclusion, we need to restore Hee Kyeng Ru as the historical meaningful building and use it as a representative cultural building in Gwangju.

• Restorative Dentistry and Endodontics
• /
• v.19 no.2
• /
• pp.585-601
• /
• 1994

The purpose of this study was to evaluate the ability of several intracoronal base materials to prevent cervical leakage of a bleaching agent into the dentinal tubules and along the root canal. In this study, thirty-two anterior teeth were used. After lingual access was prepared in each tooth, tooth was instrumented with a step-back technique to a Nos. 40-50 using K-type files. All teeth were obturated with a lateral condensation technique. Excess gutta percha was removed with a warm instrument to the facial level of the CEJ. Teeth were divided into four groups : Teeth in control group were not filled with base material. Teeth in groups 1, 2, and 3 had 2mm of gutta percha removed with a warm instrument, then Dycal, Fuki II LC and Z-100 were filled with palstic instruments on the top of the gutta percha respectively. All teeth were bleached for 7 days, fresh bleach was added for another 7 days, then a 10 % methylene blue dye was placed inside the access preparation. They were stored at $37^{\circ}C$ and $100^{\circ}C$ humidity for 5 days. Each tooth was sectioned perpendicular to the long axis using a diamond disk. Initial cuts were made at the most coronal level of facial and lingual CEJ's, then another cuts continued appically in the levels of 0.5mm, 1.5mm, and 2.0mm respectively. The amount of dye leakage through the dentinal tubules was determined at each cut section. In addition, when the cut specimen was determined to be last penetration of any dye, this level was recorded as depth of apical leakage from the coronal terminus of the gutta percha, Dycal, Fuji II LC and Z-100. The acquired data were analyzed by Tukey's Multiple Range Test adn Cochran-Mantel-Haenszel Test to see if there was any statistically significant difference in dye penetration and linear apical leakage among the groups. The results were as follows : 1. Control group at levels of CEJ and 0.5mm, group 3 at level of 1.5mm, and group 2 AND 3 at level of 2.0mm showed the least dye penetration through the facial or lingual dentinal tubules, but there were no significant difference among three groups. 2. Group 2 at levels of CEJ and 0.5mm, group 3 at level of 1.5mm, and group 2 and 3 at level of 2.0mm showed the least dye penetration through the proximal dentinal tubules, but there were no significant difference among control group, group 2, and group 3. 3. Group 1 showed the greatest dye penetration through the facial or lingual and proximal dentinal tubules at all levels, and there were significant difference with other three groups. 4. Control group and group 1 showed 2mm apical dye leakage at facial or lingual and proximal aspects, group 2 showed 1.5mm, and group 3 showed 0.5mm.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.10
• /
• pp.837-844
• /
• 2014

Automotive manufacturers have recently developed various technologies for improving fuel economy and satisfying enhanced emission regulations. The ultra-lean direct injection engine is a promising technology because it has the advantage of improving thermal efficiency through the deliberate control of ignition. A conventional LPG engine has been redesigned to an ultra-lean-burn LPG direct injection engine in order to adopt combustion system of ultra-lean-burn. This study is aimed at investigating the effect of a change in the compression ratio on the performance and emission characteristics of a lean-burn LPG engine. The fuel consumption, heat release rate, combustion pressure, and emission characteristics are estimated depending on changing the effect of compression ratio. When the compression ratio is increased, it is difficult to improve the fuel consumption owing to an unstable combustion state, but the total hydrocarbon and nitrogen oxide emissions are reduced.

• Korean Journal of Materials Research
• /
• v.8 no.9
• /
• pp.807-812
• /
• 1998

Interfacial reaction and mechanical properties between Sn-Bi-X ternary alloys(X : 2Cu. 2Sb 5In) and Cu-substrate were studied. Cu/solder joints were subjected to aging treatments for up to 60days to see interfacial reaction at $100^{\circ}C$ and then were examined changes of microstructure and interfacial compound by optical microscopy, SEM and EDS. Cu/solder joints were aged to 30days and then loaded to failure at cross head speed of 0.3mm $\textrm{min}^{-1}$ to measure strength and elongation. According to the result of EDS, it is supposed that the soldered interfacial zone was composed of $\textrm{Cu}_{3}\textrm{Sn}$ and $\textrm{Cu}_{6}\textrm{Sn}_{5}$. According to the tensile test of Cu/solder joint, joint strength was decreased by aging treatment. Fractographs of Cu/Sn-Bi solder detailed the effect of aging on fracture behavior. When intermetallic was thin, the fracture occurred through the solder. But as the interfacial intermetallic is thickened, the fracture propagated along the intermetallic/solder interface.

• The Research Journal of the Costume Culture
• /
• v.8 no.1
• /
• pp.65-76
• /
• 2000

The purposes of this study were to claassify of clothing-wearing motives, to analyze tendency of fashion in campus, and to propose fashion merchandising plans and marketing strategies of companies for female college students. Research had been done during 1 week each on April and October in 1998 and 1999. Sixty-two students in spring semester and 54 student in fall semester were surveyed and analyzed. Their grades and majors were not considered in this study. Fashion Diary had been written by students and then their statements were analyzed by the means of the qualitative data analysis. Following conclusions were obtained from this study. 1. Clothing-wearing motives were classified with 'group depending on daily work', 'group depending on image', 'group depending on body supplement', 'group depending on weather', 'group of fashion following', 'group depending on courtesy', 'group depending on mood', and 'group of unconcerning'. 2. The fashion tendency of the students were layered look and they preferred casual styles, such as round t-shirts, jean pants, and cardigans. The color of white, black, and gray were prevalent for top wear, and the color of blue, black, beige for bottom wear in both seasons. For shoes, color of black, brown, white were popular. For bags, black, blue, and khaki color were prevailed. 3. The proposals obtained from this study are as follows : 1) Production of clothing enforced functional and practical base is wanted for 'group depending on daily work'. 2) Designs considering body parts such as hip, arm hole, shoulder, and thigh are needed. 3) Utilization of new materials such as waterproof with ventilation, opaque (means 'not see-through'), antipollution finishing process are required. 4) Simple designs of clothing which could be performed by herself with various accessories. Thermochromic materials are wanted for 'group of fashion following'. 5) Diversity of semi-suit is required for 'group depending on courtesy'.

• Journal of the Korean Society of Floral Art and Design
• /
• no.43
• /
• pp.3-17
• /
• 2020

Through color analysis and survey of seasonal display cases using flower materials in department stores, hotels, and retailers, which are representative commercial spaces in Korea and abroad, it is designed to recognize the need for color planning that applies seasonal colors and emotional adjectives, away from the traditional method of relying on the season, shape and texture of materials, in the process of flower displays. The research method analyzed the colors used in the 48 domestic and foreign commercial space flower display cases collected. Based on this, the first expert questionnaire collected adjectives extraction and seasonal coordinates reminiscent of the case and examined the suitability of emotional adjectives extracted by the second public survey. The research results extracted typical colors and tones of spring, summer, fall, and winter, and recognized seasonal emotional adjectives. Based on these results, We could see that the color scheme should be advanced in the flower display, which used to depend solely on the shape or texture of the flower material, to produce the intended emotional design.