• Composites Research
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• v.14 no.2
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• pp.13-21
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• 2001

Substituting composite structures for conventional metallic structures has many advantages because of higher specific stiffness and specific strength of composite materials. In this work, one-piece driveshafts composed of carbon/epoxy and glass/epoxy composites were designed and manufactured for a rear wheel drive automobile satisfying three design specifications, such as static torque transmission capability, torsional buckling and the fundamental natural bending frequency. Single lap adhesive joint was used to join the composite shaft and the aluminum yoke. The torque transmission capability of the adhesively bonded composite shaft was calculated with respect to bonding length and yoke thickness by finite element analysis and compared with the experimental result. Torque transmission capability was based on the Tsai-Wu failure index fur composite shaft and the failure model which incorporated the nonlinear mechanical behavior of aluminum yoke and epoxy adhesive. From the experiments and the finite element analyses, it was found that the static torque transmission capability of the composite driveshaft was highest at the critical yoke thickness, and saturated beyond the critical length. Also, it was found that the one-piece composite driveshaft had 40% weight saving effect compared with a conventional two-piece steel driveshaft.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.341-347
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• 2011

To develop a healthy functional food containing Rubus coreanus fruit (RCF) powder with different degrees of ripening, the composition, physicochemical properties, and antioxidant activity of native RCF during ripening were investigated and compared with Rubus occidentalis fruit (ROF). Ripened RCF was bright red in color, whereas ripened ROF was dull and dark red in color. The seeds of RCF were softer and smaller than those of ROF. Crude protein, crude lipid, and total sugar content of RCF powder increased with increased ripening time, whereas ash and total dietary fiber contents decreased with increased ripening time. Color differences increased with Increased ripening. Eighteen types of amino acids were analyzed from RCF, and glutamic acid had the highest content. RCF powder had the highest level of potassium and calcium and did not contain any hazardous metals. Mineral and organic acid contents decreased according to ripening.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2030-2037
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• 2012

The purpose of this research is to suggest a model or method of needs analysis for designing syllabuses. As the learner-centered approach in teaching and learning methods becomes general, the learners' needs or wants should be reflected on the syllabus design. However, standardized scores in the previous research have disadvantages to be distorted in data interpretations because the difference between the maximum value and minimum value is so big compared to the Likert 5 scales. To solve this disadvantage, the Max-Min method is used in the needs analysis for the syllabus design. So, the differences are presented. Needs analyses need to be selected variously according to situations. Thus, further researches are needed to develop several new methods as well as the Max-Min method or the standardized score method for the whole needs analyses.

• Archives of design research
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• v.3 no.1
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• pp.34-70
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• 1990

Recently the tourism industry has achieved rapid growth and thus stands out as a means for the improvement of international payments and the acquirement of foreign currency. In particular, the hotel and major tourist travel industries have been developed for the inducement of foreign tourists. However, the manu-facturing and sales indust\ulcornerries of tourism folklore haven't developed. The reason is that the endeavor to attract tourists has been more emphasized than the development of tourism folklore which includes chief shopping items and indust-rialization. Tourism folklore plays a great role not only as material evidence of a tourist's visit to a country or region but also as a gift and a souvenir. Also it represents the image and the degree of the industrial development of the nation, so it should be congruent with the nature and the images of the region. Nevertheless, our tourism folklore has been merely mass produced by specific companies that do not represent the region's image and nature in their products. Tourism folklore development can raise the image of Choongnam and serve as a catalyst to induce tourists. Also, it can be an avenue for com$$\mu$ity publicity and industrialization. Thus, this study has examined and analyzed original products made with textiles and metal materials whether can be developed into tourism folklore. Also this study presents the example of developed tourism folklore works in a foreign country. It tries to give the unique symbolic image of Choongnam by developing the original products with Choongnam' s own materials. However, this study has shown that the actual conditions of tourism folklore development in Choongnam are seriously inferior to other industries. The producers are limited. Moreover, the product items are coarse. Many problems are being brought up which should be improved. Hereafter, to develop Choongnam's own tourism folklore, it should be carried out with financial and political support from the government, design development by industrial circles, professional design training and marketing research by the sellers.

• Journal of the Korean Geographical Society
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• v.45 no.6
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• pp.766-787
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• 2010

This study seeks to clarify the process of development and the change of freight flows in the influence areas of Pyeongtaek and Dangjin Port, which opened lately. The results of analysis are as follows: from development period to growth period, the relation between the development of the port and the change of the hinterland and foreland shows no great change and the freight concentration rates of the first hinterland and foreland decreased, but those of periphery region increased. While the composition rate of import and export freight of vehicle, fuel and energy decreased, the rate of imported freights (iron or steel, other textile articles, rag and organic compounds) and exported freight (manufacture of basic metals) increased. The reasons for such changes in influence areas of port were the increase of export to China and the U.S.A. in the development period, the increase of import from China in the growth period and the diversification of nations from which fuel and energy were imported.

• Transactions of Materials Processing
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• v.24 no.1
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• pp.52-61
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• 2015

Evaluation of the elevated temperature flow stress for thermoplastic fiber metal laminates(TFMLs) sheet, comprised of two aluminum sheets in the exterior layers and a self-reinforced polypropylene(SRPP) in the interior layer, was conducted. The flow stress as a function of temperature should be evaluated prior to the actual forming of these materials. The flow stress can be obtained experimentally by uniaxial tensile tests or analytically by deriving a flow stress model. However, the flow stress curve of TFMLs cannot be predicted properly by existing flow stress models because the deformation with temperature of these types of materials is different from that of a generic pure metallic material. Therefore, the flow stress model, which includes the effect of the temperature, should be carefully identified. In the current study, the flow stress of TFMLs were first predicted by using existing flow stress models such as Hollomon, Ludwik, and Johnson-Cook models. It is noted that these existing models could not effectively predict the flow stress. Flow stress models such as the modified Hollomon and modified Ludwik model were proposed with respect to temperatures of $23^{\circ}C$, $60^{\circ}C$, $90^{\circ}C$, $120^{\circ}C$. Then the stress-strain curves, which were predicted using the proposed flow stress models, were compared to the stress-strain curves obtained from experiments. It is confirmed that the proposed flow stress models can predict properly the temperature dependent flow stress of TFMLs.

• Transactions of Materials Processing
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• v.24 no.1
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• pp.37-43
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• 2015

The purpose of the current study is to improve the clinching joint strength of aluminum and fiber metal laminates (FMLs) comprised of three layers. The joining of FML and Al 5052 by a conventional clinching joint has some disadvantages such as necking of the upper sheet, lack of interlocking, defects caused by the vertical load, and especially loss of strength of the composite material due to the low ductility. In the current study, a tapered-hole clinching method is proposed as an alternative for the joining of Al 5052 and FMLs. A hole with a tapered shape is formed before the joining process. The design parameters were evaluated using the Taguchi method for the geometry of the tapered hole in order to determine the maximum separation load. The diameter of the punch corner, clearance, punch stroke and the tapered length were used as the main variables in the Taguchi method. In conclusion, the contribution ratio for each of the fours variable examined was 35.07%, 22.44%, 21.32% and 14.11%, respectively. In addition, the appropriate combination of the design parameters can make a 5% improvement in the vertical direction joint strength.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.4
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• pp.83-91
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• 2015

Under impact or blast loads, concrete behaves with different mechanical properties comparing to the static loading conditions. In other words, with high strain rate, mechanical properties of concrete vary significantly. To evaluate the compressive characteristics of concrete with high strain rate, SHPB(Split Hopkinson Pressure Bar) test is typically used. However, because SHPB test method has been developed for metallic materials, it is necessary to verify the applicability of SHPB for brittle materials such as concrete. Also, there have been little researches on the evaluations of mechanical characteristics of UHPC under high strain rate conditions. This study has been performed to evaluate and analyse the compressive characteristics of plain concrete and UHPC with SHPB test apparatus. Also, to verify the applicability of SHPB test for concrete, direct displacement image analysis with high speed camera was performed for the comparisons with analytical solutions for SHPB test.

• International Commerce and Information Review
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• v.17 no.1
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• pp.309-337
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• 2015

Recently, Korea had virtually reached an FTA deal with China on November 10, 2014 after the 14 rounds of negotiation during past two and half years. The two countries agreed to the FTA's 22 chapters, including products, services, investment, e-commerce, finance, communication, and other trade issues, but rice and several sensitive agricultural and fisheries products were excluded from the deal. Korea and China will remove their import tariffs on more than 90 percent of all products and more than 85 percent of imports by value within 20 years once the FTA is implemented. This paper intends to analyze the impacts of Korea-China FTA on the major industries in Daegu-Gyeongbuk region. Considering the statistics on the bilateral trade between China and Daegu-Gyeongbuk region, import tariff rates of the two countries, trade specialization indices of the major industries, and the package of Korea-China FTA deal, this study investigated the sectoral effects of Korea-China FTA on the four main industries, textiles, electrical-electronics, machinery and auto parts, and steel and iron industries in that region.

• Composites Research
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• v.28 no.6
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• pp.372-377
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• 2015

In this study, we analyzed process numerically when a bogie frame skin is manufactured by applying resin transfer molding process using composite material instead of steel. Processing time was compared based on the various thickness of bogie frame skin and the weight variation of a skin was also considered. As a result, RTM processing time decreases and the weight of a bogie reduces as the thickness of frame skin increases with the assumption that fiber volume is constant inside the skin. By considering these results as the information to estimate the production cost, trade-off between two fields, processing time and structural properties, can be performed in design optimization to produce bogie frame.