• 한국생산제조학회지
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• 제24권6호
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• pp.682-686
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• 2015

The objective of this study is to validate the performance of the current $k-{\epsilon}$ turbulence model for a single-phase turbulent natural convection, which has been considered an important phenomenon in nuclear safety. As a result, the natural convection problems in the 2D and 3D cavities previously studied are calculated by using the ANSYS Fluent software. The present results show that the current $k-{\epsilon}$ turbulent model accounting for the buoyancy effect is in good agreement with the previous results for the natural convection problems in the 2D and 3D cavities although some improvements should be required to get better prediction.

• 패션비즈니스
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• 제8권5호
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• pp.125-135
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• 2004

Hair coloring before the 1980s was mostly to hide white hair by dying in black. With the introduction of color TV, however, the size of the coloring market has been expanding. Nowadays, artificial synthetic dyes are widely used, which, though advantageous in many points, have problems such as harmful effects on the human body, carcinogenesis, environmental contamination and damage on hair. On the contrary, natural vegetables obtained from Curcuma Longa L., A. catechu, polygonum indigo, henna, etc. are little harmful to hair or the skin of the head and cause few environmental problems. In addition, as they are natural materials collected from nature, they are considered positively by consumers. Thus the present study started from the necessity of research on the convenient use of environment?friendly and side-effect-free natural dyes, coloring technology for reproducing original color, the improvement of adhesion rate, etc. From the present research were obtained yellow color from Curcuma Longa L., brown from A. catechu, blue from polygonum indigo and orange from henna. It is expected that, based on materials from previous researches, there may be more researches on the use of natural dyes as hair colors.

• 한국전산유체공학회지
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• 제7권1호
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• pp.10-19
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• 2002

The non-staggered(collocated) grid approach in which all the solution variables are located at the centers of control volumes is very popular for incompressible flow analyses because of its numerical efficiency on the curvilinear or unstructured grids. Rhie and Chow's paper is the first in using non-staggered grid method for SIMPLE algorithm, where pressure weighted interpolation was used to prevent decoupling of pressure and velocity. But it has been known that this non-staggered grid method has stability problems when pressure fields are nonlinear like in natural convection flows. Also Rhie-Chow scheme generates large numerical diffusion near curved walls. The cause of these unwanted problems is too large pressure damping term compared to the magnitude of face velocity. In this study the magnitude of pressure damping term of Rhie-Chow's method is limited to 1∼10% of face velocity to prevent physically unreasonable solutions. The wall pressure extrapolation which is necessary for cell-centered FVM is another source of numerical errors. Some methods are applied in a unstructured FV solver and analyzed in view of numerical accuracy. Here, two natural convection problems are solved to check the effect of the Rhie-Chow's method on numerical stability. And numerical diffusion from Rhie-Chow's method is studied by solving the inviscid flow around a circular cylinder.

• 한국의류학회지
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• 제34권7호
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• pp.1205-1219
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• 2010

This study analyzes the conditions and products of internet shopping malls that sell natural dyeing products. In this study, 98 natural dyeing internet shopping malls were selected. The results of this study are as follows. The locations of the internet shopping malls were Gyeonggi-do, Seoul, Jeollanam-do, Gyeongsangbuk-do, Gwang-ju (city), Daegu (city), Busan (city), Gyeongsangnam-do, and Jeju-do. The most frequent dyes of the natural dyeing products were loess, followed by charcoal, indigo, and persimmon. Indigo was most frequently used in Seoul, with loess and charcoal most frequent in Gyeonggi-do. Persimmon, indigo, loess, and charcoal were mainly used in Jeollanam-do, with persimmon and loess in the Gyeongsangbuk-do, and persimmon in Jeju-do. The highest ordered product categories were accessories, followed by adult clothing, interior decoration products, and bedding. The most frequent products were bedclothes, followed by scarves, female shirts, blouses, pillows, female jackets, and vests. Regarding the price of products, 150,000-200,000 won was the highest for the Saenghwal Hanbok, with 10,000-30,000 won for underwear, 30,000-60,000 won for accessories, and 100,000-150,000 won for bedding. Concerning product information, 58.2% of internet shopping malls offer the product size and almost half of them did not show the properties or directions for handling the product. Based on the research results, the problems of the conditions and products of natural dyeing internet shopping mall were derived. The results show that the natural dyes of internet shopping malls lacked regional symbolism, the products were not specialized, and product information was not fully offered to consumers. To solve these problems, the strategies for marketing the promotion of the natural dyeing internet shopping mall were, ‘Using natural dyes from local resources’, ‘Market oriented and specialized item design’, and ‘Offer right product information’.

• 천문학회보
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• 제44권2호
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• pp.56.1-56.1
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• 2019

We are producing and consuming more data than ever before. Massive data allow us to better understand the world around us, yet they bring a new set of challenges due to their inherent noise and sheer enormity in size. Without smart algorithms and infrastructures, big data problems will remain intractable, and the same is true in natural science research. The mission of data science as a research field is to develop and apply computational methods in support of and in the replacement of costly practices in handling data. In this talk, I will introduce how data science and deep learning has been used for solving various problems in natural sciences. In particular, I will present a case study of analyzing high-resolution satellite images to infer socioeconomic scales of developing countries.

• 복식
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• 제52권3호
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• pp.123-137
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• 2002

The purpose of this study is to analyze the actual condition and problems of current ready-made shrouds. Current shrouds were formed after the 20th century and therefore are quite apart from its traditional precedents of Chosun Dynasty. In this respect, several problems can be pointed out. 1. The use of natural colored hemp as a primary textile of current shrouds is far from our tradition. Silk, ramie, and cotton have to be used together with hemp. Also, more variety of colors can be used other than natural white. 2. The size of ready-made shrouds has to be categorized at least into three: large, medium and small 3. The pattern and sowing method of Dopo(도포) and Wonsam(원삼) should be corrected in line with those of the traditional Dopo(도포) and Wonsam(원삼). 4. The design and items of current ready-made shrouds have to break away from the standardized convention and should seek more of a variety that our rich tradition provide. 5. The rational index should be suggested so that consumers can compared the quality and price of ready-made shrouds available at their hands.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.400-404
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• 2004

There are many methods to find solutions for Integer Programming problems (IPs) such as the Branch-Bound philosophy or the Cutting Plane algorithm. However, most of them have a problem that is the explosion of sets in the computing process. In addition, GA is known as a heuristic search algorithm for solutions of optimization problems. It is started from a random initial guess solution and attempting to find one that is the best under some criteria and conditions. The paper will study an artificial intelligent method to solve IPs by using Genetic Algorithms (GAs). The original solution of this was presented in the papers of Fabricio Olivetti de Francaand and Kimmo Nieminen [2003]. However, both have several limitations which causes could be operations in GAs. The paper proposes a method to upgrade these operations and computational results are also shown to support these upgrades.

• 한국농공학회논문집
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• 제61권2호
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• pp.51-61
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• 2019

In this study, interest in rural life of good natural environment rather than busy life is increasing as human life is extended by scientific and medical technology and society has improved. The reckless development of rural villages has caused social problems as the natural environment has been damaged, failing to function as a pleasant home. To address these problems, the government has implemented a rural village development project, but if the site is selected incorrectly, the residents may not be recruited, or applicants may lose their status, or the portion of the infrastructure building fee may increase. In order to prepare objective and clear assessment methods for the target site not to cause such problems, a layering analysis method (AHP: Analytic Method) was used to identify the current status of the rural village formation project, draw assessment items, and determine the importance of each item.

• 한국패션뷰티학회지
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• 제4권2호
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• pp.31-41
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• 2006

As chemistry dyes has considerably developed with industrial society, natural dyeing has gone out of people's head for a long time. But the serious problems from environmental pollutions and ecological damages make people look far Well-being. Natural dyeing also has concentrated again and the interests about it are growing larger and larger. Well-being that a modern person pursues and a Natural dyeing walk along a same string of connection. That is, people want their life to change from quantity matters into qualities. The relations of the natural dying which has the color of nature and Well-being phenomenons are analyzed through dissertations and references. The study about the correlations between natural dying and well-being shows that many advantages of natural dyestuff and the effects of dyestuff are definitely needed to people living in modern times. Also for the protection of an ecosystem, rapid popularization and the development of new design is completely required.

• 한국전산유체공학회지
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• 제20권4호
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• pp.14-20
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• 2015

Without electirc power to cool down the hot reactor core, passive systems utilizing natural circulation are becoming a big specialty of recent neculear systems after the severe accident in Fukusima. When we consider the natural circulation in a pool, thermal mixing phenomena may start from single phase circulation and can continue to two phase condition. Since the CUPID code, which has been developed for two-phase flow analysis, can deal with the phase transition phenomena, the CUPID would be pertinent to natural convection problems in single- and two-phase conditions. Thus, the CUPID should be validated against single- and two-phase natural circulation phenomena. For the first step of the validation process, this study is focused on the validation of single-phase natural circulation. Moreover, the CUPID code solves the fluid properties by the relationship to pressure and temperature from the steam table considering non-condensable gas effects, so that the effects from variable properties are included. Simple square thermal cavity problems are tested for laminar and turbulent conditions against numerical and experimental data. Throughout the investigation, it is found that the variable properties can affect the flow field in laminar condition, but the effect becomes weak in turbulence condition, and the CUPID code implementing steam table is capable of analyzing single phase natural circualtion phenomena.