• Journal of the Korean housing association
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• v.13 no.5
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• pp.59-69
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• 2002

This study is designed to derive a cost estimation method for the management of green areas in apartment housing blocks. For this purpose, quantity of green areas, their usages, management techniques were analyzed through a survey of residents. In this process, contingent valuation method(CVM) is utilized to evaluate the cost of green areas. The survey was conducted for about two weeks in June of 2002. The amount of willingness to pay(WTP) for green area management is calculated by the CVM program. The findings are as follows; First, the residents want more green areas in their apartment blocks, as well as in the surrounding urban areas, due to the shortage of green areas in their living environments. Second, the residents' opinion on green area is summarized as that of natural environment protectionist - it helps living environment to be more amenable and contributes the preservation of urban and global environments. This fact can be interpreted as the peoples profound recognition toward green areas. Third, the contingent valuation method(CVM) is suitable to evaluate WTP for management costs of green areas. Fourth, more than half of the residents(61.6%) agreed upon the costs of green area supply and management. calculated by the CVM. Estimated WTP is ￦ 1,900~2,400 per month per household.

• Korean Journal of Construction Engineering and Management
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• v.4 no.4 s.16
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• pp.137-144
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• 2003

Recently, the interest in a complex building increases rapidly in Korea. High-rise complex is not simply the combination of a residential apartment and a business office as previous but a building with the object of the convenience of the residents familiar with city-life style through adapting the high class life style and new residential culture to the business space, and the efficiency in using the limited building site in the town. This study presents an exploratory analysis focusing the structural system with the help of the extensive survey of the construction site in Korea, and aims a guideline for the structural design and construction of high rise complex. Through the survey, change and development in the design and the construction can be seen as the height and size of the complex grow. It is almost indispensable to design a structural system against lateral forces like earthquake or wind, which is usually measured by story drift ratio or story displacement. Improvement of the structural materials and their usages is also included for the efficiency of the structural system. Useful slab-beam system contributing to the decrease of the story height is still a concern.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.1-16
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• 2015

In this review, we summarized some of membrane processes using the ion exchange membrane typically used in energy applications. Ion exchange membranes are classified according to their functions, formations (e.g. heterogeneous, homogeneous), and polymer type. Furthermore, various methods to prepare cation exchange membranes and anion exchange membranes were discussed in detail and also illustrated through a thorough review of the literature works. There are numerous reports highlighting recent research trends in the ion exchange membrane fabrication, however, in this review we will focus more on discussing the development made in ion exchange membranes and their potential usages in future technologies.

• The Mathematical Education
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• v.51 no.2
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• pp.131-144
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• 2012

The purpose of this study is to investigate the change of mathematics pre-service teachers' teaching behaviors in microteaching. This study is organized along the following lines: 1) mathematics pre-service teachers conduct twice microteachings, 2) the microteaching recordings and lesson observation reports written by pre-service teachers are analyzed. Through reviewing the first microteaching, pre-service teacher have reviewed and found out improvements of their teaching. In the second microteaching, pre-service teachers' teaching behaviors have been positively and effectively changed with respect to teaching methods, proposal of learning objectives, prior knowledge usage, presenting lesson's content, concise descriptions, brief language usages, multimedia, and appropriate questions. However, they frequently used inappropriate expressions from their unconscious habits. Therefore, the educational institutions should provide opportunities involved in well-structured microteaching training program with pre-service teachers, which in turn, help pre-service teachers to have more positive teaching competence.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.8
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• pp.1348-1355
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• 1997

Machine element design is a very important course in the undergraduate program of mechanical engineering in that it presents traditional design concepts. While computer aided design(CAD) receives more attention, students tend to ignore the machine element design or traditional design concepts. However, design methodologies related to machine elements are utilized quite often in practical fields. Also, design methodologies provide good insight for the decision making process of modern design. Generally, CAD is used for simple drafting without the real design process in the undergraduate program. Design software has been developed for various machine elements. Through menu display, a user can select or furnish the design input such as design objects, dimensions, environmental forces and usages, and safety factors. Then the software carries out the design processes which are the same as those of textbooks. The result of the design is filtered to have the values in the standards. The designed machine element is drawn via commercial CAD software. The software has been developed with C language on a personal computer. The developed software is being utilized successfully in a design course, and the experiences are discussed in this paper. The software can be used in industries which require the repeated process of the machine element design.

• Journal of Digital Contents Society
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• v.11 no.3
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• pp.399-406
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• 2010

This study deals with the proposition of the diversification strategy for participation contents service based on the open IPTV policy, and the strategic implication for IPTV players. This paper demonstrates implication for activation of participation contents to IPTV players with reference to differentiation of usages and needs to internet and television. Thus this paper proposes for diversification of player's competency (1) variety of production channels for contents, (2) enhanced accessibility, and (3) the strategic consistency for industrial eco-system. Moreover, this paper suggests that device differentiation for creation of demand, boosting customer satisfaction & immersion through closely interlocking contents.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.2
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• pp.58-66
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• 1997

Ti alloys, with the advantageous tensile strength/density ratio and the chemical stability, have been used widely in the aerospace and chemical engineering industries and their usages are still expanding in various industrial areas. In the automotive industry, because of their superior merits of weight reduction and fuel saving, Ti alloys are expected to be used as various part materials including connecting rods, engine valves, springs and retainers, which are all subjected to the fatigue loads. In this study, using Ti-3A1-2.5V, the effects of temperature and microstructure change on fatigue crack propagation has been investigated. Five different microstructures were tested at the temperatures of room temperature, 20$0^{\circ}C$, 30$0^{\circ}C$ and 40$0^{\circ}C$ under the same frequency 20Hz. Some of the conclusions obtained are as follows: (1)Microstructurally, the morphology of less $\alpha$-phase and finer lamellar structure of $\alpha$ and $\beta$-Ti showed better registance to the fatigue crack propagation. (2)Fatigue crack growth rate increased with test temperature.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.1
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• pp.79-91
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• 2010

This study investigates the differences between purchasers and non-purchasers of naturally dyed-products in the hobby/leisure, media exposure, usage of media program type, and information sources about naturally dyed-products. Data were collected from a total 213 Korean females ranging from 20 to 59 years old, and in data analyses, there were partially significant differences between the two groups. Compared to non-purchasers of naturally dyed-products, Purchasers of those ones were more interested in traditional fields and nature. They are also more exposed to newspapers and less exposed to TV. Purchasers used more informational and educational programs as well as personal and commercial information sources (store visual presentations and sales persons) than non-purchasers. However, the differences between these two groups were not significant in the interests of fashion/cooking and sports, Internet exposure, entertainment programs and public/commercial information sources about naturally dyed-products. Marketers can use the results to access the market of naturally dyed-products for promotion.

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.55-64
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• 2006

Deicing work is usually considered as a main part of winter road management activity. The deicing includes the physical method which removes snow with tools and the chemical method which melts snow with deicing materials. When removing snow using deicing materials, using excessive deicing materials will cause the environment and budget problems. When deicing materials are used less than the required amount, snow will remain on the road surface. In this research, the performance of deicing marerials has been evaluated and the amount of deicing materials has been determined by the laboratory and the field experiments. Also the adequate usages of deicing materials has been proposed.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.669-674
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• 2001

Electric Arc Furnace Dust (EAF Dust) Is residual dust produced during the manufacturing of metal products from heavily heated electric arc furnace. Many researches have focused on recycling and reusing EAF Dust for industrial and construction purposes. However, most of these researches were aimed at obtaining useful heavy metal powders by treating toxic metallic materials in EAF Dust. Also, few researches dealt with using EAF Dust as admixture in concrete mixture (i.e., slag dust). In this study, EAF Dust is used as admixture in concrete mixture content considering economical feasibility and construction applicability. The concrete specimens mixed with EAF Dust is then tested in compression and tension to study its strength and ductility as well as its failure mechanism. The compression and tension (by split cylinder test) test results are compared to the results from the specimens without EAF Dust to understand the chemical stability and mechanical characteristic of concrete specimens with EAF Dust. For the experiment, 6 types of admixture added concrete were studied: ⑴Combination of EAF Dust and blast-furnace slag in 1 to 1 ratio, ⑵Combination of EAF Dust and blast-furnace slag in 1 to 2 ratio, ⑶EAF Dust only, ⑷blast-furnace slag only, ⑸fly ash only, and ⑹no admixture. The experimental results show that the strength of EAF Dust added specimen has lower early age strength but higher 28 day strength when compared to other specimens. Also, the Elastic Modulus of EAF Dust is higher(28 days) than other specimens. The study results prove that EAF Dust can be used as an effective admixture in concrete for specific usages.