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        검색결과 6

        1.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : It is well known that low temperature cracking is one of the most serious distresses on asphalt pavement, especially for northern U.S. (including Alaska), Canada and the northern part of south Korea. The risk of thermal cracking can be numerically measured by estimating thermal stress of a given asphalt mixture. This thermal stress can be computed by low temperature creep testing. Currently, in-direct tensile (IDT) mixture creep test mentioned in AASHTO specification is used for measuring low temperature creep properties of a given asphalt mixture. However, IDT requires the use of expensive testing equipment for performing the sophisticated analysis process, however, very few laboratories utilize this equipment. In this paper, a new and simple performance test (SPT) method: bending beam rheometer (BBR) mixture creep testing equipment is introduced, and the estimated experimental results were compared with those of conventional IDT tests. METHODS: Three different asphalt mixtures containing reclaimed asphalt pavement (RAP) and roofing shingles were prepared in the Korea Expressway Corporation (KEC) research laboratory. Using the BBR and IDT, the low temperature creep stiffness data were measured and subsequently computed. Using a simple power-law function, the creep stiffness data were converted into relaxation modulus, and subsequently compared. Finally, thermal stress results were computed from relaxation modulus master curve using Gaussian quadrature approach with condierations of 24 Gauss number. RESULTS: In the case of the conventional asphalt mixture, similar trends were observed when the relaxation modulus and thermal stress results were compared. In the case of RAP and Shingle added mixtures, relatively different computation results were obtained. It can be estimated that different experimental surroundings and specimen sizes affected the results. CONCLUSIONS: It can be said that the BBR mixture creep test can be a more viable approach for measuring low temperature properties of asphalt mixture compared to expensive and complex IDT testing methods. However, more extensive research and analysis are required to further verify the feasibility of the BBR mixture creep test.
        4,000원
        3.
        2016.07 구독 인증기관·개인회원 무료
        The purpose of this study is to present theoretical and experimental evidence for a niche strategy for small and medium online shopping malls to run business against large famous shopping malls prevailing the E-commerce market. For this, the present study demonstrates how chronic construal levels of consumers may affect their alternative choice for online shopping via various contexts (Experiment 1-3) and categories (Experiment 3-5). This series of experiments suggests that consumers with high construal level can be defined as a group that is relatively less susceptible to reputation of the shopping malls. Thus, strategically targeting this group of consumers will help small and medium-sized online malls lacking store reputation to mitigate their competitive disadvantage. Based on both existing literature and the experimental results as above, this research discusses possible methods for small and medium-sized online shopping malls to target high-construal segmentation.
        4.
        2015.02 서비스 종료(열람 제한)
        This research study aims to examine who vulnerable people are on disaster & emergency situations in South Korea. There are various vulnerable people such as children, senior citizen, the disabled and foreigners. I choose foreigners who live in South Korea as vulnerable group among them because there would be no system and study for helping foreigners on the situations, comparing to other vulnerable groups. Foreigners' residents often could have accidents from disaster and emergency situations because they live in South Korea for long time and various places such as factory, farmland, fishery and so on. To solve these problems, we should be willing to cope with emergencies for foreigners’ residents. First of all, it is necessary that a variety of educations and promotions should be a prerequisite to foreign residents' easy access to safety. As well, revitalizing a variety of communities, we need to figure out a way to cope with emergent disasters. This study will present some preparations to solve the problems, as exhibited in the following. First, multilingual emergency disaster & emergency services applications. Second, foreign residents provide disaster & emergency related promotional media. Third, education and social institutions established disaster & emergency. Forth, selection foreign volunteer firefighters. The research being sought by this study is a set of findings that contribute to the development of practical and realistic policy recommendations which may be used for disaster & emergency management practitioners, as well as policy and decision makers at all level.
        6.
        2006.09 KCI 등재 서비스 종료(열람 제한)
        We study on the dynamic interaction with a simulated physical-biological coupled model response to nutrient reduction scenario in Jinhae Bay. According to the low relative errors, high regression coefficients of COD and DIN, and realistic distribution in comparison to the observation, our coupled model could be applicable for assessing the marine ecosystem response to nutrient input reduction in Jinhae Bay. Due to the new construction and expansion of sewage treatment plant from our government, we reduce 50% nutrient inputs near Masan Bay and sewage treatment plant. COD achieves Level Ⅱ in Korea standard of the water quality from the middle of the Masan Bay to all around Jinhae Bay except the inner Masan Bay remaining at Level Ⅲ. When our experiment reduces 50% nutrient inputs near Masan Bay and Dukdong sewage treatment plant simultaneously, COD decreases to about 0.1-1.2 mg/L (128°30’~128°40’ E , 35°05’~35°11’ N). The COD from the middle of the Masan Bay to Jinhae Bay achieves Level Ⅱ.