• Elastomers and Composites
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• v.44 no.1
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• pp.63-68
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• 2009

Recently, much attention has focused on the permanent deformation of roads in hot summer and cracks in cold winter, which are detrimental to safe driving. This leads to necessity of modification of asphalt to resist those deformation. In this study, a type of modified asphalt was prepared by addition of a photoinitiator which is activated by ultraviolet lay. The mechanical and rheololgical properties of photoinitiator-modified asphalt were examined using UTM and rheometer. Results showed that the modified asphalt was effected by ultraviolet and thus tensile strength and storage modulus increased, due to molecular attraction, with initiator content and irradiation dose. Thermal analysis showed less weight loss upon photoinitiator-modification and this indicated that the molecular attraction is the result of cross linking reaction between asphalt molecules induced by photoinitiator. According to long term ultraviolet curing test, properties of the photoinitiator-modified asphalt did not decrease or even increase for 20 years. This indicates that useful life of the asphalt could be extended by addition of photoinitiator.

• Elastomers and Composites
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• v.45 no.3
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• pp.217-222
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• 2010

Paved roads are suffered from the permanent plastic deformation in hot summer and cracks in cold winter, which are detrimental to safe driving. This leads to necessity of modification of asphalt to resist those deformation. In this study, two kinds of modifiers were examined; organic polymers and a photoinitiator which is activated by ultraviolet lay. The mechanical and rheololgical properties of modified asphalts were examined using UTM and rheometer. Results showed that the properties were varied depending on the types of polymer and irradiation time. UV irradiation increased the tensile strength and storage modulus of thermoplastic polymer-modified asphalt, however UV was not effective on thermoset polymer. According to long term ultraviolet curing test, properties of the polymer/photoinitiator-modified asphalt did not decrease, but rather increase for 20 years. This indicates that the useful life of the asphalt could be extended by addition of photoinitiator.

• Journal of the Korean Chemical Society
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• v.20 no.2
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• pp.158-165
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• 1976

The anionic polymerization of ${\varepsilon}$-caprolactam with N,N'-adipyl-bis-${\varepsilon}$-caprolactam as an initiator and potassium hydroxide as a catalyst was studied under various conditions.It was found that concentration of catalyst and initiator was 4.2 and 1.6 mole %, and polymerization temperature of 130$^{\circ}C$C, polymerization time of 1.5 hours was the optimum condition. The intrinsic viscosity and molecular weight of the obtained polymer was over 0.9 dl/g and 12,000. The polymerization was carried out in the presence of N-acyl-${\varepsilon}$-caprolactam as an initiator, it was observed that the reactivity of N,N'-adipyl-bis-${\varepsilon}$-caprolactam was greater than both of the N-benzoyl-${\varepsilon}$-caprolactam and N-acetyl-${\varepsilon}$-caprolactam. In general it was also observed that the intrinsic viscosity and yield of conversion was increased as an increasing of concentration of catalyst and initiator and also highly depend on temperature.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.3
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• pp.283-289
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• 2011

As leisure boats become large-scaled and high value-added, their design requirements gradually get more complicated and accordingly their manufacturing processes get more complicated than those of existing ones. Leisure boat builders overseas make efforts to overcome this circumstance by establishing a 3-D model-based design system which is based on the concept of PLM. On the other hand, Korean shipbuilders still remain in the development process of traditional leisure boats which are mainly based on 2-D drawings. There have been some efforts made to have the 3-D model-based design system; however, they belong to a very early stage. This study carried out initial research to apply DMU technology to the development process of leisure boats. It established the design process based on a DMU model and proved its usefulness through a case study on the design of 40-ft class aluminum leisure boats.

• Journal of the Korea Society for Simulation
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• v.20 no.3
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• pp.11-18
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• 2011

Korea army is operating K-10 FAASV (Field Artillery Ammunition Support Vehicle) for K-9 SP (Self-Propelled artillery) and examining employment of FAASV for K-55 SP. At present, the FAASV for K-55 SP has been developed as a prototype. To decide the employment of this FAASV for K-55 SP, previous research for operational effectiveness of this equipment is needed. Therefore in this paper, we presented the result of the operational effectiveness of the FAASV for K-55 SP using a wargame model, FEAM (Fire Execution Analytic Model) which is used to analyze formation, weapon system and operation in army artillery field. Based on the result of the FEAM simulation, we introduced the operational effectiveness of FAASV for K-55 SP, which is able to be applied to decide whether employ FAASV for K-55 SP or not.

• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.250-253
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• 1975

The acid milk containing grape juice was prepared from natural grape juice, acid milk and sugar as raw materials, and the stability of the drink was studied. The following results were obtained. 1. The milk mixed with natural grape juice formed coagulated precipitate by coupling of the colloidal materials in the juice with the milk protein and the formation of precipitate was accelerated by pasteurization. 2. The pectin in natural grape juice was affected on the stability of the product, and the stability increased with decrease in the content of pectin. When the content of pectin in natural grape juice was lower than 2.5mg%, the precipitate was not formed in the drink containing 10 to 20% of the juice. 3. The acid milk drink containing the natural grape juice treated with pectinase, not formed precipitate by pasteurization at $85^{\circ}C$, for 20 minutes and can be preserved for long term.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.183-189
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• 2020

This study was carried out to find out the acquisition effect by measurement periods of adult learners learning through English pattern practice. The subjects of this study were divided into adult learner groups including the learners in their 40s and those who were over 65 and the child group who were 8 years old as a comparative group. After the subjects had a pre-test at first, person agreement and tense were instructed though English pattern practice and right after that, they had a post-test. Then 4 weeks later, they had a delayed test. As a result, the acquisition result of adult learners learning though English pattern practice showed the largest rise by those in their 40s and the learners of those over 65. However the adult learners aged over 65 showed the largest drop in delayed test of the reading comprehension. Based on these results, it is necessary to develop teaching method for adult learners in consideration of their characters and weak points.

• Korean Journal of Construction Engineering and Management
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• v.9 no.4
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• pp.84-91
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• 2008

"Eco-friendly construction" is an emerging issue in the building industry. Main purpose of the eco-friendly construction is to sustain the health and environment of building residents and to minimize the harmful effect on their environment. Apartment residents have great concern on eco-product, since many cases are reported that Sick Building Syndrome is caused by toxic substance from building materials. Environmental performance is to meet through using the highest grade eco-friendly materials. However, generally eco-friendly materials are more expensive than normal materials, Therefore, using eco-friendly materials at public housing project is limited to economical aspect. The purpose of this paper is development of eco-friendly material selection model considered cost efficiency. The selection of Eco-friendly finishing materials and their methods are constructed to consider environmental performance level and cost index compositively. Development of eco-friendly material selection method is economic and reasonable one when public housing is constructed.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.953-956
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• 2007

"Eco-friendly construction"is an emerging issue in the building industry. Main purpose of the eco-friendly construction is to sustain the health and environment of building residents and to minimize the harmful effect on their environment. Apartment residents have great concern on eco-product, since many cases are reported that Sick Building Syndrome is caused by toxic substance from building materials. Environmental performance is to meet through using the highest grade eco-friendly materials. However, generally eco-friendly materials are more expensive than normal materials. Therefore using eco-friendly materials at public housing project is limited to economical aspect. The purpose of this paper is development of eco-friendly material selection model considered cost efficiency. The selection of Eco-friendly finishing materials and their methods are constructed to consider environmental performance level and cost index compositively. Development of eco-friendly material selection method is economic and reasonable one when public housing is constructed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.461-467
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• 2017

As the number of smart devices increases, e-book contents and services are proliferating. However, the text based e-book is difficult for a hearing-impairment person to understand. In this paper, we developed an android based application in which we can choose an e-book text file and each sentence is translated to sign-language elements which are shown in videos that are retrieved from the sign-language contents server. We used the korean sentence to sign-language translation algorithm based on the morpheme analysis. The proposed translation algorithm consists of 3 stages. Firstly, some elements in a sentence are removed for typical sign-language usages. Secondly, the tense of the sentence and the expression alteration are applied. Finally, the honorific forms are considered and word positions in the sentence are revised. We also proposed a new method to evaluate the performance of the translation algorithm and demonstrated the superiority of the algorithm through the translation results of 100 reference sentences.