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        검색결과 2,007

        1884.
        2015.04 서비스 종료(열람 제한)
        Tuned Mass Damper (TMD) is a prominent mean of controlling structural vibration. Typically the TMDs are installed at the top of the structure. In this study, the effectiveness of the multiple tuned mass dampers (MTMD) distributed along with the height of structure is investigated for seismic loading. A ten storey building with lateral degree of freedom is modeled with distributed tuned mass dampers in the platform of MatLab R2010a. Though the first mode of a MDOF system dominates in response of the structure, it is also observed that the other mode can also have a significant role in the response reduction. Suitable location for the installation of the TMDs and there tuning frequencies are selected based on the mode shape and frequencies of the uncontrolled structure respectively. It is observed that distributed TMD is more effective than Single TMD and Multiple TMD installed at top of the structure in response reduction.
        1885.
        2015.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We have carried out photometric follow-up observations of bright transiting extrasolar planets using the CbNUOJ 0.6 m telescope. We have tested the possibility of obtaining high photometric precision by applying the telescope defocus technique, allowing the use of several hundred seconds in exposure time for a single measurement. We demonstrate that this technique is capable of obtaining a root-mean-square scatter of sub-millimagnitude order over several hours for a V ~10 host star, typical for transiting planets detected from ground-based survey facilities. We compared our results with transit observations from a telescope operated in in-focus mode. High photometric precision was obtained due to the collection of a larger amount of photons, resulting in a higher signal compared to other random and systematic noise sources. Accurate telescope tracking is likely to further contribute to lowering systematic noise by exposing the same pixels on the CCD. Furthermore, a longer exposure time helps reduce the effect of scintillation noise which otherwise has a significant effect for small-aperture telescopes operated in in-focus mode. Finally we present the results of modelling four light-curves in which a root-mean-square scatter of 0.70 to 2.3 milli-magnitudes was achieved.
        1886.
        2015.03 KCI 등재 서비스 종료(열람 제한)
        Purpose This study reviews Cameroon’s – economic growth, crisis, and recovery, aiming t review the principal factors of Cameroon’s real economic growth; explore the causes of its economic crisis analyze the determinants of its economic recovery; and suggest appropriate policies to ameliorate economic growth. Research design, data, and methodology – By reviewing the relevant literature and economic indicators, we observed that from the 1980s to the present, Cameroon experienced all the possible business cycle phases: economic prosperity (until 1985), economic and social crisis (1986-1994), and renewed economic growth (after 1995). Results – As a result of the economic changes in Cameroon, its macroeconomic indicators have evolved. Poverty and inequality have changed in both quantitative and qualitative terms. Throughout the examined period, rural poverty has become more widespread, deeper, and more severe than urban poverty, while inequality has experienced greater increases in urban areas relative to rural zones. Conclusions –To reap maximum benefits and reduce poverty from these economic changes, Cameroon needs to liberalize trade and foreign exchange transactions to attract foreign investment, especially during the current globalization.
        1887.
        2015.02 서비스 종료(열람 제한)
        The relationship between international trade and foreign direct investment has been become one of the most important issues among scholars’ researches. The majority of scholars made promoting effects of foreign direct investment in the export trade as their main research content, which focused on the relationship between foreign direct investment and trade effects in the host country to verify alternative or complementary effects. Recently, they have begun to regard the home country as the research object, with the latest trade gravity model to study the FDI’s effect in the home country’s import and export trade. This paper elaborates the theory of Chinese foreign direct investment and trade effects, which highlights China’s foreign direct investment of trade effects, influencing factors of these effects and their path mechanism. Followed by the performance of the gravity model, empirical test comes that the external direct investment contributes to trade creation and regional differences, and put forward policy suggestions accordingly.
        1888.
        2015.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        본 연구는 냉동연근의 최적 제조 공정을 위하여 수행하 였다. 냉동 전처리로 blanching 하고, -20, -70, -196℃ 각각 다른 냉동온도에서 동결한 냉동연근의 품질을 측정하였다. 최적 blanching 조건은 미생물 수, 물성, 총 페놀 함량, 관능 평가 등의 결과를 바탕으로, 100℃에서 5분간 처리로 설정 하였다. 여러 냉동조건에서 동결한 연근의 SEM 사진을 비교한 결과, -20℃에서 동결한 연근의 조직이 가장 많이 파괴되었고 –70℃에서 동결한 연근의 조직 단면 구조가 대조구와 가장 유사하였다. 항산화능은 동결 시 감소하는 경향을 나타냈고, 처리구간에 유의적인(p<0.05) 차이는 없 었다. 총 페놀 함량은 모든 냉동연근에서 감소하는 경향을 보였는데 -20℃에서 가장 낮았고, drip loss 또한 -20℃에서 3.73%로 가장 높았다. 따라서 본 연구 결과, -20℃에서의 일반적인 냉동보다는 gas nitrogen convection chamber에서 의 -70℃로 동결하는 것이 고품질의 냉동연근을 생산할 수 있는 최적 냉동방법이라고 판단된다.
        1889.
        2015.02 서비스 종료(열람 제한)
        According to a recent analysis of NASA, the year 2014 now ranks as the warmest on record since 1880. Africa is widely held to be highly vulnerable to future climate change related hazards, and Ethiopia is often cited as one of the most extreme examples. The country’s economy is highly exposed to climate variability and extremes and the nature of agriculture, primarily rain-fed is sensitive to fluctuations in rainfall, which forms the basis of the economy supporting roughly 42% GDP and 85% employment. Wahlström M (2009) reported that over the last two decades (1988-2007), 76% of all disaster events were hydrological, meteorological or climatological in nature. In this review, a great concern is given for extreme conditions (flood and drought) particularly climate change related hazards and tries to look at the challenges, mitigation and policies. Climate change, drought and flood will continue to be a primary concern for many Ethiopian and even agricultural production and water supplies will become more severely diminished. Starting from 1970-1996 droughts and the resulting food shortage have affected millions and cause for the death of a significant number of people and in 2009 Ethiopia has experienced a delay in the main rainy season, particularly in northeastern areas, resulting in 50-70 % of agricultural land being sown for cropping. Ethiopia has also experienced a major flood in 1988, 1993, 1994, 1995, 1996 and 2006 and climate change, including extreme events like drought and flood affected areas will likely become more widely spread. Recently, flash floods affected big cities, including Addis Ababa and Dire Dawa (death of 300 people) and result in considerable damage to lives, livelihoods and property. Despite the hugely damaging effect that natural and man-made disasters have on Ethiopia’s economic development, little is done to prevent them. There are significant challenges to reduce climate change related hazards, but linking of climate change adaptation with disaster risk reduction and effective strategies to prevent hazards from becoming disasters and managing those disasters that do occur would make a lasting contribution to the quality of life and sustainable livelihoods. Several factors contribute to Ethiopia’s high vulnerability to disasters, but here the authors will focus on institutional frameworks and policy. There are several NGO and governmental climate change actors in Ethiopia. The country’s National Policy on Disaster Prevention and Management (NPDPM) was prepared in 1993. Ethiopia has also ratified the United Nations Framework Convention on Climate Change (UNFCCC) and under the mechanism, a National Adaptation Program of Action (NAPA) was produced in 2001 with an ambition to identify ‘immediate and urgent’ adaptation activities that address current and anticipated adverse effects of climate change and extreme climate events. The Environmental policy of Ethiopia indicates that environmental sustainability to be recognized in policies and strategies as a key prerequisite. In line with this the Environmental Protection Agency (EPA), was established and mainly assumes a regulatory role and coordinates various activities and included policy on climate change and pollution, particularly on promoting climate monitoring programs as the country is sensitive to changes in climate, identifying a firm and demonstrable commitment to the principle of containing climate change and fostering to use hydro, geothermal and solar energy to minimize an emission of greenhouse gases.
        1890.
        2014.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this study, we investigated the effect of space plasmas on the floating potential variation of a low-altitude, polar-orbiting satellite using the Langmuir Probe (LP) measurement onboard the STSAT-1 spacecraft. We focused on small potential drops, for which the estimation of plasma density and temperature from LP is available. The floating potential varied according to the variations of plasma density and temperature, similar to the previously reported observations. Most of the potential drops occurred around the nightside auroral region. However, unlike the previous studies where large potential drops were observed with the precipitation of auroral electrons, the potential drops occurred before or after the precipitation of auroral electrons. Statistical analysis shows that the potential drops have good correlation with the temperature increase of cold electrons, which suggests the small potential drops be mainly controlled by the cold ionospheric plasmas.
        1891.
        2014.12 KCI 등재 서비스 종료(열람 제한)
        Purpose This study aims – to examine new product adoption (NPA) in the context of clothing in Iran. Research design, data, and methodology – Data were gathered from cloth owners in Iran, focusing on famous cloth brands cloth. Further, using the proportionate stratified sampling method, a total 438 usable questionnaires were returned and analyzed through the use of structural equation modeling (SEM). In addition, LISREL software was used to analyze the data collected through the structured questionnaires. Results – Overall, the study findings indicate that education has a positive effect on new product adoption, whereas the impacts of religion and Attitude towards Consumption (ATC) on new product adoption are negative and significant, but the effect of age, peers, and income on new product adoption is not significant. Conclusions – Using date obtained from a large random sample of Iranian consumers, this study offers a deeper understanding of the attitudinal and personal antecedents of consumers’ new product adoption in an emerging market. Using the findings of the articles and conclusions will be useful for market researchers and, of course, business persons.
        1892.
        2014.12 KCI 등재 서비스 종료(열람 제한)
        Purpose This – paper examines Kazakh women’s spending patterns and buying behavior. Research design, data, and methodology – After thoroughly reviewing the related literature on consumer behavior in general, and female consumer behavior in particular, both questionnaires and in-depth personal interviews were used to collect data from 400 Kazakh women consumers equally chosen from the age groups 20-30, 30-40, 40-50, and above 50. Results – A stratified and convenient sample was employed, and the selected five hypotheses were proved using the Karl Pearson Coefficient of Correlation. Related to spending patterns, 40 and 35 percent of the 20-30 and 30-40 age groups, respectively, of Kazakh women spend their incomes on personal items, as against 30 percent from both the 40-50 and 50 and above age groups. Twenty-five and 35 percent of the 40-50 and 50 and above age group, respectively, take decisions based on product quality, whereas this percentage is at its mite in the below 40 age group. Conclusions – The buying behavior of Kazakh women consumers is revealed; the results proffer useful background information to formulate marketing strategies.
        1897.
        2014.09 서비스 종료(열람 제한)
        Development of the central nervous system (CNS) occurs normally in mammalian fetus despite lower temperature in the brain region than in the heart. To investigate the effects of temperature niche on the neural differentiation of stem cells in vitro, P19 embryonic carcinoma (EC) stem cells and N2a neuroblastoma stem cells were induced to undergo neural differentiation by retinoic acid and LiCl, respectively. The cells were analyzed for the expression of neural marker genes during 12 days differentiation. Although there were Map2 and NCAM expressions in both groups, no clear difference was found. Similarly, expression patterns of Tuj1 and NF-M were not different in both groups, showing more intensive staining patterns at day 12 than those at days 4 and 8, respectively. However, more cells expressed GFAP markedly at day 12 in 37℃ group. There was little expression of the above markers in N2a cells during differentiation except for Ngn2 and Tuj1. It was found that Ngn2 was expressed more intensely at days 6 and 9 in 33℃ group. Tuj1 expression showed a similar pattern to those of P19 EC cells. RT-PCR analysis also showed that the expressed transcripts did not quite different in both groups, although they were different among the days of differentiation. Thus, it appears that neural differentiation occurs normally with a slight delay and probably less cell death in the cells at 33℃ than that at 37℃.
        1898.
        2014.09 서비스 종료(열람 제한)
        Chemoresistance is one of the main problems to treat different kinds of cancers or cancer cells. Therefore, it is necessary to find out the strategies to make the cancer cells sensitive to chemotherapy along with optimal dosage of drugs. We examined sensitivity of MCF7 cells through pretreating with an epigenetic modulator, azacytidine (AzaC) to doxorubicin (Dox). The cells were treated with 5 and 10 mM of AzaC for a week, subsequently with 50, 100 and 500 nM of doxorubicin for 24 and 48h. It was found that pretreatment of AzaC significantly enhance the sensitivity of MCF7 cells to Dox, inducing cell death. After 24h 15% cells underwent apoptosis in 500 nM dox treatment group while 23.4% cells death occurred in AzaC pre treatment group. After 48h MCF7 cells treated with Dox showed 19.0% cell death while AzaC sensitized cells showed 50.0% cells death when exposed to 500 nM of Dox for 48h. Western blot analysis showed the upregulations in the expression of bax, caspase-3, caspase-9 and p53 in AzaC-sensitized MCF7 cells treated with Dox as compared to those treated with only Dox. There was no clear indication for pro-apoptosis genes in the cells treated with individual drugs. These results showed that pretreatment with the epigenetic modulator significantly increased the sensitivity of MCF7 cells to Dox. Therefore it is concluded that demethylation event might enhance the activity of DNA intercalating agents to induce DNA damage in breast cancer cells.
        1899.
        2014.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Next Generation Small Satellite-1 (NEXTSat-1) is scheduled to launch in 2017 and Instruments for the Study of Space Storm (ISSS) is planned to be onboard the NEXTSat-1. High Energy Particle Detector (HEPD) is one of the equipment comprising ISSS and the main objective of HEPD is to measure the high energy particles streaming into the Earth radiation belt during the event of a space storm, especially, electrons and protons, to obtain the flux information of those particles. For the design of HEPD, the Geometrical Factor was calculated to be 0.05 to be consistent with the targets of measurement and the structure of telescope with field of view of 33.4° was designed using this factor. In order to decide the thickness of the detector sensor and the classification of the detection channels, a simulation was performed using GEANT4. Based on the simulation results, two silicon detectors with 1 mm thickness were selected and the aluminum foil of 0.05 mm is placed right in front of the silicon detectors to shield low energy particles. The detection channels are divided into an electron channel and two proton channels based on the measured LET of the particle. If the measured LET is less than 0.8 MeV, the particle belongs to the electron channel, otherwise it belongs to proton channels. HEPD is installed in the direction of 0°,45°,90° against the along-track of a satellite to enable the efficient measurement of high energy particles. HEPD detects electrons with the energy of 0.1 MeV to several MeV and protons with the energy of more than a few MeV. Thus, the study on the dynamic mechanism of these particles in the Earth radiation belt will be performed.
        1900.
        2014.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The application of software engineering is not common in the development of astronomical observation system. While there were component-wise developments in the past, large-scale comprehensive system developments are more common in these days. In this study, current methodologies of development are reviewed to select a proper one for the development of astronomical observation system and the result of the application is presented. As the subject of this study, a project of operation software development for an astronomical observation system which runs on the ground is selected. And the output management technique based on Component Based Development which is one of the relatively recent methodologies has been applied. Since the nature of the system requires lots of arithmetic algorithms and it has great impact on the overall performance of the entire system, a prototype model is developed to verify major functions and performance. Consequently, it was possible to verify the compliance with the product requirements through the requirement tracing table and also it was possible to keep to the schedule. Besides, it was suggested that a few improvements could be possible based on the experience of the application of conventional output management technique. This study is the first application of the software development methodology in the domestic astronomical observation system area. The process and results of this study would contribute to the investigation for a more appropriate methodology in the area of similar system development.