• Korean Journal of Materials Research
• /
• v.9 no.2
• /
• pp.217-225
• /
• 1999

The effect on the pitting corrosion resistance of laser welding and surface treatment developed as a repair method of stream generator tubing material that was a major component of primary system at nuclear power plant was observed. Some heat-treated Alloy 600 tubing materials used at domestic nuclear power plants were laser-surface observed. Some heat-treated Alloy 600 tubing materials used at domestic nuclear power plants were laser-surface melted and the microstructural characteristics were examined. The pitting corrosion resistance was examined through Ep(pitting potential) and degree of pit generation by means of the electrochemical tests and the immersion tests respectively. The pit formation characteristics were investigated through microstructural changes and the pit initiation site and pit morphology. The test results showed that the pitting corrosion resistances was increased in the order of the followings; sensitized Alloy 600, solution annealed alloy600, and laser surface melted Alloy 600. Pits were initiated preferably at Ti-containing inclusions and their surroundings in all tested specimens and it is believed that higher pitting resistance of laser-surface treated Alloy 600 was caused by fine, homogeneous distribution of non-soluble inclusions, the disappearance of grain boundary, and the formation of dense, stable oxide film. The major element of corrosion products filled in the pit was Cr. On the other hand, Fe was enriched in the deposit formed on the pit.

• KIEAE Journal
• /
• v.13 no.2
• /
• pp.47-52
• /
• 2013

The problems of light pollution first became an issue in the 1970s when astronomers identified the degradation of the night sky due to the increase in lighting associated with development and growth. As more impacts to the environment by lighting have been identified, many attempts have been made for reducing light pollutions. To prevent light pollution and increase energy efficiency, Seoul Metropolitan Government(SMG) replaced metal halide road lighting to LED luminaire in four arterial highway in Seoul. The present study compared the lighting characteristics of metal halide and LED luminaire in terms of Korea Standard for road lighting(KS A 3701) and BUG rating from Illuminating Engineering Society of North America(IESNA). The results showed that LED luminaire increased road surface luminance up to 2 times in average compared to the metal halide environment. Also, LED luminaire reduced the glare value by 2 times and luminous flux over 50% than the metal halide luminaire. In comparison with the BUG ratings, LED luminaire rated 1 degree lower for the backlight ratings and 3-4 degrees lower for the uplight ratings. The measured values testified that the LED luminaire is effective for roadway lighting and light pollution reduction.

• The KIPS Transactions:PartA
• /
• v.17A no.1
• /
• pp.45-52
• /
• 2010

The National Assessment of Educational Achievement has been conducted in the form of sampling assessment until 2007, but it was converted into sampling assessment one hundred percent working with relevant whole students in 2008. Therefore, the necessity of new study on the national assessment system of educational achievement was on the rise. The National Assessment System of Educational Achievement, which was implemented in this thesis was designed to analyze educational achievement status all over the province, total score and score frequency distribution per subject, item difficulty and item discrimination, degree of attraction of wrong answers, educational achievement per subject, gender, region, office of education, school, individual and status of students with high educational achievement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.10
• /
• pp.938-945
• /
• 2003

We fabricated Ni-substrate for YBCO coated conductors and evaluated the effects of pressing and annealing temperature and time on texture. Ni substrate was fabricated by powder metallurgy technique and compacts were prepared by applying uniaxial or isostatic pressure. The texture of substrate made by applying cold isostatic pressure (CIP) was stronger than that by uniaxial pressure which we attribute to the fact that the CIP method provided higher density and more uniform density distribution. It was observed that the substrate annealed at 400 C showed both retained texture and recrystallized texture. On the other hand, the texture of substrate significantly improved at annealing temperature above 500 C, forming strong 4-fold symmetry, [111] II ND texture, and FWHM of 9∼10 . It is to be noted that the degree of texture was almost independent of annealing temperature (500∼1000 C) and annealing time(1∼54 min, at 1000 C). EBSD and AFM analysis indicated that 99% of grain boundaries was low angle grain boundary and RMS was approximately 3 nm, respectively. Development of strong cube texture and high fraction of low angle grain boundary of Ni-substrate made by powder metallurgy technique in our study is considered to be suitable for the application of YBCO coated conductors.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.9
• /
• pp.994-1000
• /
• 2004

We studied the characteristics of annular phase gratings as spatial frequency filters. We first calculated the Fraunhofer diffraction patterns of annular gratings and then got the modulation transfer function (MTF) from the zeroth order Hankel transform of the intensity distribution function. Binaryphase annular grating shows higher diffraction efficiency than binary phase rectangular grating. But the MTF decreases linearly in the low-frequency region as that of rectangular grating does. The diffraction pattern of 4-phase annular grating is similar to that of 2-phase grating and hence MTFs of the two are much alike. For 8-phase annular grating, the 7th order diffracted beam is the lowest one next to the first. Consequently, the diffraction efficiency is very high and the MTF graph is curved upward. The diffracted beams except the first order are negligible and hence the MTF characteristics are more improved in the case of 16-phase grating. But the degree of improvement becomes lowered c(Impaled with 8-phase grating. We made a 16-phase annular grating and measured its MTF. The experimental result agrees well with the calculated one.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2008.04a
• /
• pp.306-310
• /
• 2008

Fuzzy regression, a nonparametric method, can be quite useful in estimating the relationships among variables where the available data are very limited and imprecise. It can also serve as a sound methodology that can be applied to a variety of management and engineering problems where variables are interacting in an uncertain, qualitative, and fuzzy way. A close examination of the fuzzy regression algorithm reveals that the resulting possibility distribution of fuzzy parameters, which makes this technique attractive in a fuzzy environment, is dependent upon an h parameter value. The h value, which is between 0 and 1, is referred to as the degree of fit of the estimated fuzzy linear model to the given data, and is subjectively selected by a decision maker (DM) as an input to the model. The selection of a proper value of h is important in fuzzy regression, because it determines the range of the posibility ditributions of the fuzzy parameters. In this paper, we discuss the interdependent relationship among the h value, membership function shape, and the spreads of fuzzy parameters in fuzzy linear regression with fuzzy input-output using shape-preserving operations.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.16 no.4 s.44
• /
• pp.393-403
• /
• 1992

This Study intended to provide positioning strategies of brand Image for ladies' ready to wear by analysing the perceptual dimensions of working women. The subjects were devided into two groups according to the fashion involvement, and in each group, a positioning map was composed by use of multidimensional scaling. 251 subjects of this study were gathered into stratified sample groups from working women in Seoul, being subdivided according to their each occupation and age. The data were analysed by frequency, percentage, average, $x^{2}-test$, 1-test, Factor Analysis, cronbach's $\alpha$. Also, KYST, PROFIT, PREFMAP for multidimensional scaling were used. The results were as follows. 1. Two groups were identified according to degree of fashion involvement: high-involvement group, and low-involvement group. 2. From the analysis of the similarity of brand image, high involvement group percieved greater difference in brand image than low involvement group. 3. From the analysis of the evaluation of brand attributes, the evaluations in self expression, fashionability, design, sales promotion activity, sociality, quality, fit showed differences bet-ween high involvement group and low involvement group. 4. From the analysis of the preference of brand image, the distribution of preference and ideal point were different between high involvement group and low involvement group.

• Asian Journal of Business Environment
• /
• v.4 no.2
• /
• pp.17-21
• /
• 2014

Purpose - The paper analyzes basic indicators characterizing the volume of energy sector activity in the Russian Federation, Privolzhsky Federal district, Republic of Tatarstan. Research design, data, and methodology - The study analyzed data from the Privolzhsky Federal district, specifically, industrial production volume, electricity production, energy consumption, energy-balance data, capital investments, and capital investment structure. An array of data has been investigated in recent years. The dataset's dynamics were analyzed in 1998. Fixed capital investment dynamics were studied in 1946 the figures were converted to a comparable form using the index method. Trends were analyzed using multivariate statistics methods and the Statgraphics software package. Results - Hypothesis 1. There are sectoral disproportions in energy flows,taking into account the volume of electricity production and consumption. Trends in electricity production in general coincide with industrial production volume trends. Energy flows have disparities in individual territorial units, and in general. Hypothesis 2. The degree of sectoral economic stability decreases with insufficient levels of investment in fixed capital energy organizations. Conclusions - Because totalelectricity production is largely determined by fixed capital investments, the study of their trends and patterns will coordinate efforts on investment operations in this area.

• Asian Journal of Business Environment
• /
• v.7 no.1
• /
• pp.25-29
• /
• 2017

Purpose - In this paper, we categorize and segment the 28 national universities in South Korea and measure the degree of dissimilarity (or similarity) between pairs of ones by using dissimilarity distance matrix and cluster analysis, respectively, based on the seven quantitative evaluation of educational conditions (percentage of small-scale courses, percentage of lecture by the faculty, collection of books per student, material purchase per student, percentage of building capacity, percentage of real estate capacity and rate of accommodation) in 2015. In addition, multidimensional scaling (MDS) techniques can obtain visual representation for exploring patterns of proximities among 28 national universities based on seven attributes of educational conditions. Research design, data, and methodology - This work is carried out by the 2015 Announcement of University Information, which is provided by Ministry of Education in South Korea and utilized by multivariate analyses with CLUSTER, PROXIMITIES and ALSCAL modules in IBM SPSS 23.0. Results - We make certain that 28 national universities can be categorized into five clusters which have similar traits by applying two-stage cluster analysis. MDS is utilized to perform positioning of grouped places of cluster and 28 national universities joining every cluster. Conclusions - Both types and traits of each national university can be relatively assessed and practically utilized for each university competitiveness based on underlying results.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.7
• /
• pp.169-178
• /
• 2020

This study examines the current situation of responsibility accounting and proposed management solutions according to responsibility centers on public universities in Vietnam. The study applies quantitative research methods, and collected data through structured questionnaires to 138 public universities in Vietnam in 2019, receiving back 55 valid questionnaires. The data was cleaned and analyzed with SPSS software. The results show that most public universities in Vietnam assigned management responsibility to their departments, but responsibility accounting was not comprehensive since many universities are not financially autonomous. The Kruskal Wallis Test was conducted to compare the current situation of responsibility accounting among universities by the degree of autonomy and by geographic area. The research found out that totally autonomous universities assigned management responsibility to responsibility centers better than semi-autonomous and non-autonomous universities did. Regarding the evaluation of management responsibility, universities in Central Vietnam rated specific quantitative criteria, residual income (RI) and returns on investment (ROI) higher than universities in the North and the South of Vietnam did. However, universities in the South of Vietnam rated the evaluation of profits by department higher than the rest. The study also suggests structure for establishing responsibility centers in accordance with public universities in Vietnam.