• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.3
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• pp.97-103
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• 2012

The combustion chamber and nozzle of a liquid rocket engine should be protected from the high temperature combustion gas generated by the chamber. An upper-stage nozzle extension has a large expansion ratio, therefore, The light-weight refractory materials have been used since the weight impact on the launcher performance is crucial. Gas film cooling method was used before, but was not applicable nowadays. Ablative cooling method and radiative cooling method with niobium alloy, Ni-based superalloy and ceramic based composite have been used to this day.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2456-2463
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• 2011

Conventional railways are less competitive than other land transportation means in term of speed, and thus users preference and transportation share for rail system are relatively lower than others. For example, most of the conventional lines except the Seoul~Busan corridor run at an average speed of 70 km/h or less, which imposes certain constraints on roles and functions as the trunk lines. In this regard, the speed of the conventional lines should be improved up to 200 km/h to gain competitiveness, promote balanced regional development and lead the era of low carbon green growth. As track system is one of the most important elements for the speed-up, it is critical to come up with optimum technical solutions. Improvement of ballast track structure with efficient track installation can provide structural stability for higher speed and ensure operational safety with lower maintenance efforts. Thus, this study focuses on consequences followed by the speed-up including increase of load imposed on the track and impacts on track components, and provide solutions for track maintenance by analyzing impact on the track structure by speed. Also, it compares ballast and concrete tracks under designing and construction and considers how to meet needs for passengers comfort and environmental requirements as a strategic approach.

• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.63-70
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• 2013

The multimedia data of game affects the immersion of the game depending on its quality. It is difficult to design the evaluation criteria of artistic quality of the data. But, in a technical point of view, it is possible to evaluate its quality. Thus, the design of evaluation standard can ensure the reliability and objectivity of quality. However, multimedia data quality evaluation metrics had not yet been designed. Therefore, in this study, we extracted quality evaluation elements of Game Multimedia Data, and verified the reliability of the elements. And we defined detailed evaluation items of each element, developed Multimedia Data Quality Evaluation Metrics. We expect that the results of this study will serve as a guide in the development of high-quality games, have a positive impact on the growth of the game industry.

• Journal of Digital Convergence
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• v.10 no.6
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• pp.17-22
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• 2012

The technological innovation of IT industry is the competitive tool for them to survive in the environment of an intensive competition. This technological innovation is critical in the survival of firms, but various factors should be considered to embody technological innovation success. This paper aims to identify the determinant factors of the outcome which influence the technological innovation based on the IT industry, and set up a model for measuring technological innovation success. A hypothesis was established for the impact relation between technological innovation success and government support level, which was verified through the logistic regression analysis. In conclusion, in terms of government support, IT manufacturing companies to the success of product innovation, technology development(R&D) and commercialization of direct support is needed for the financial support. And, the success of process innovation is accomplished through manpower training of technical personnel.

• Journal of Plant Biotechnology
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• v.44 no.2
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• pp.156-163
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• 2017

A greenhouse experiment was conducted for evaluation of ecological effects of transgenic melon plants in the rhizospheric soil in terms of soil properties, enzyme activities and microbial communities. Organic matter content of soil under transgenic melon plants was significantly higher than that of soil with non-transgenic melon plants. Significant variations were observed in organic matter, total P and K in soil cultivation with transgenic melon plants. There were also significant variations in the total numbers of colony forming units of fungi, actinomycetes and bacteria between soils treated with transgenic and non-transgenic melon plants. Transgenic and non-transgenic melon significantly enhanced several enzymes activities including urease, acid phosphatase, alkalin phosphatase, arysulphtase, ${\beta}$ glucosidase, dehydrogenase, protease and catalase. Soil polyphenoloxidase activity of $T_1$ transgenic melon was lower than that of $T_0$ transgenic melon and a non-melon plant during the same period. The first generation transgenic melon plants ($T_0$) showed significantly greater (p<0.05) effect on the activitiy of arylsulfatase, which increased from $2.540{\times}10^6CFU\;g^{-1}$ (control) to $19.860{\times}10^6CFU\;g^{-1}$ ($T_0$). These results clearly indicated that transgenic melon might change microbial communities, enzyme activities and soil chemical properties.

• Safety and Health at Work
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• v.8 no.3
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• pp.315-317
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• 2017

We present the case of a 45-year-old man with a history of benzene exposure who developed splenic marginal zone lymphoma. For 6 years, he had worked in an enclosed space cleaning instruments with benzene. He was diagnosed with splenic marginal zone lymphoma 19 years after retirement. During his time of working in the laboratory in the 1980s, working environments were not monitored for hazardous materials. We indirectly estimated the cumulative level of past benzene exposure using job-exposure matrices and technical assumptions. Care must be taken in investigating the relevance of occupational benzene exposure in the occurrence of indolent B-cell lymphoma. Because of the long latency period and because occupational measurement data do not exist for the period during the patient's exposure, the epidemiological impact of benzene exposure may be underestimated.

• Smart Structures and Systems
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• v.16 no.6
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• pp.1049-1068
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• 2015

In the paper, the authors propose the application of operational deflection shapes (ODS) for the detection of structural changes in technical objects. The ODS matrix is used to formulate the spatial filter that is further used for damage detection as a classical modal filter (Meirovitch and Baruh 1982, Zhang et al. 1990). The advantage of the approach lies in the fact that no modal analysis is required, even on the reference spatial filter formulation and other components apart from structural ones can be filtered (e.g. harmonics of rotational velocity). The proposed methodology was tested experimentally on a laboratory stand, a frame-like structure, excited from two sources: an impact hammer, which provided a wide-band excitation of all modes, and an electro-dynamic shaker, which simulated a harmonic component in the output spectra. The damage detection capabilities of the proposed method were tested by changing the structural properties of the model and comparing the results with the original ones. The quantitative assessment of damage was performed by employing a damage index (DI) calculation. Comparison of the output of the ODS filter and the classical modal filter is also presented and analyzed in the paper. The closing section of the paper describes the verification of the method on a real structure - a road viaduct.

• The Journal of Industrial Distribution & Business
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• v.10 no.2
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• pp.25-37
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• 2019

Purpose - The goal of this study is to analyze the differences in education performances between students of the government's financial support program and those who do not receive support at a local university in Korea. Research design, data, and methodology - The questionnaire used was NASEL. NASEL is considered a highly suitable survey tool for professors, courses, and performances in Korean universities. The 290 students who participated and 44 students do not participate in the financial support program were surveyed for 10 days. The characteristics of students were investigated by frequency analysis and technical statistics. The analysis of student collective characteristics used independent t and f-tests,and one-way ANOVA with IBM SPSS Statistics 22.0 for statistical purposes. Results - The p-value of the group receiving financial support and the group without financial support in active-collaborative learning is 0.167. The p-value of the economically supported group and the non-supported group of the faculty-student interaction is 0.281. The confidence coefficient of the active-collaborative learning questionnaire is 0.861. The reliability coefficient of the questionnaire for the faculty-student interaction questionnaire is 0.871. Conclusions - There are no clear differences in active-collaborative learning and faculty-student interaction between participating and non-participating students in the economic program.

• International Journal of Knowledge Content Development & Technology
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• v.10 no.2
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• pp.51-69
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• 2020

This paper describes global research in the field of augmented reality (22078) as indexed in Scopus database during 1992-2019, using a series of bibliometric indicators. The augmented reality (AR) research registered high 54.23% growth, averaged citation impact of 8.90 citations per paper. Nearly 1% of global output in the subject (226 papers) registered high-end citations (100+) per paper. The top 15 countries accounted for 87.05% of global publications output in the subject. The USA is in leadership position for its highest publications productivity (19.25% global share). The U.K. leads the world on relative citation index (2.05). International collaboration has been a major driver of AR research pursuits; between 11.89% and 44.04% of national share of top 15 countries in AR research appeared as international collaborative publications. AR research productivity by application types was the largest across sectors, such as education, industry and medical. Computer science has emerged as the most popular areas in AR research pursuits. Technical University of Munich, Germany and Osaka University, Japan have been the most productive organizations and Nara Institute of S&T, Japan (66.55 and 7.48) and Imperial College, London, U.K. (57.14 and 6.42) have been the most impactful organizations. M. Billinghurst and N. Navab have been the most productive authors and S. Feiner and B. MacIntyre have been the most impactful authors. IEEE Transactions on Visualization & Computer Graphics, Multimedia Tools & Applications and Virtual Reality topped the list of most productive journals.

• 전자공학회논문지 IE
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• v.47 no.2
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• pp.32-37
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• 2010

In this study, to develop union type SMD inductor core needs to have the desire of super miniaturization and high reliability, it analyzed temperature properties due to electric power value. As the temperature of electronic parts rise, it bring to technical obstacles that parts can not normal operation, it reduce the span of life to raise the fault ratio. Also, it impact to the parts by heat change power and expansive power, it can not behave exactly, and it have an effect on reliability. It measured the difference value between conditional temperature and parts temperature to union type SMD inductor core. As the results of simulation using D.C. current and resistor($R_dc$), it obtained the excellent regular current values at rising temperature of 40[$^{\circ}C$].