• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.67-78
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• 2017

Traffic congestion cost is increasing annually. Specifically congestion caused by the CDB traffic contains more than a half of the total congestion cost. Recent advancement in the field of Big Data, AI paved the way to industry revolution 4.0. And, these new technologies creates tremendous changes in the traffic information dissemination. Eventually, accurate and timely traffic information will give a positive impact on decreasing traffic congestion cost. This study, therefore, focused on developing both recurrent and non-recurrent congestion prediction models on urban roads by adopting Recurrent Neural Network(RNN), a tribe in machine learning. Two hidden layers with scaled conjugate gradient backpropagation algorithm were selected, and tested. Result of the analysis driven the authors to 25 meaningful links out of 33 total links that have appropriate mean square errors. Authors concluded that RNN model is a feasible model to predict congestion.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.4
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• pp.289-296
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• 2014

The rebar detailing is an important work influencing the final performance and quality of RC structures. But it is one of the most irrational and illogical activity in construction site. Many groups of workers, including main contractors, structural engineers, shop drawers, rebar fabricators, and etc., participate in this activity. A loosely-organized process for this activity is apt to produce a big amount of rebar loss or even degraded structures. A 3-dimensional rebar auto-placing system, called as Rebar Hub, has been designed and implemented in this research. Rebar Hub provides a totally integrated service from 3D structural modeling of buildings to rebar auto-placing considering anchorage, splice, and the length of ordered rebar. In addition, Rebar Hub can recognize the 2D drawing CAD files and then build 3D structural models which are used for the start point of 3D rebar auto-placing. After rebar auto-placing, each members of the 3D structural model have rebar information belonging to them. It means that the rebar information can be used for the afterward works such as quantity-survey, manufacturing and fabrication of rebars. Rebar Hub is showing outstanding performance while applying to practical projects. It has almost five times productivity and reduces the rebar loss up to 3~8% of the initially-surveyed amount of rebar.

• The Journal of the Acoustical Society of Korea
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• v.34 no.4
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• pp.274-281
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• 2015

Although noise-induced hearing loss (NIHL) is a significant public health problem, many people might not be aware that exposure to loud noise could occur hearing loss. The purpose of this study is to evaluate and analyze how importantly and seriously people are aware of NIHL using a 22-question survey. It was administered to random 150 people including between 20 s to 60 s. The questionnaire contained questions about i) views toward general health issues including hearing loss and tinnitus, ii) noise exposure, and iii) views toward hearing protection. Results showed that hearing loss was defined on a likert scale as 'a very big problem' by 17.33 % of respondents compared with other health issues. Surprisingly, most respondents (82 %) had not heard, read, or seen anything lately related to the issue of hearing loss. Many respondents had experience hearing problem or tinnitus under loud noise situations (85 %), however, only 11.33 % of respondents had used earplugs. Fortunately, many could be motivated to try ear protection if they were advised by a medical professional (80 %) or were aware of the potential for permeant hearing loss (78.67 %). We concluded that awareness of the potential for permanent hearing loss with noise and effective methods of hearing protection should be announced to public for preventing NIHL.

• Journal of Korea Port Economic Association
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• v.28 no.3
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• pp.27-44
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• 2012

The offshore wind farm is increasingly attractive as one of future energy sources all over the world. In addition, the capacity of an offshore wind turbine gets larger and its physical characteristics are big and heavy. In this regard, a special port is necessary to assemble, store, and transport the offshore wind systems, supporting to form the offshore wind farms. Thus, this study aims to provide a policy maker which evaluation factors can significantly affect to the optimal site selection of a offshore wind port. For this, Fuzzy-AHP method is applied to capture the relative weights. The results of this study can be summarized as follows. Five criteria in level I was defined such as the accumulation factor, the regional factor, the economic factor, the location factor, and the consortium factor. Of these, the accumulation factor(37.4%), the location factor(34.2%), and the economic factor( 24.5%) were analyzed by major factors. In level II, three assessment items of each factor were selected so that total fifteen items were formed. To sum up, the site selection of offshore wind port should consider the density of the wind industry, cargo volume of securing the economic operation of terminals, the development degree of offshore wind related industry, and the proximity to the offshore wind farms. In other words, the construction of offshore wind port should be paid attention to considering not only the proximity to offshore wind farms but also the preference of turbine manufacturing companies.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.5
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• pp.535-542
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• 2014

This research concluded that the area is most sensitively affected by the maritime traffic congestion rather than other factors including the ship's speed and fairway width. We performed a literature review for the area used in Japan, Denmark, and Shanghai ports, and analyzed by comparing with the area in Jinhae, Korea through the observation survey of marine traffic. The result of sensitivity analysis concluded that the congestion is affected by amount of 10% by changing 1 knot of the ship's speed, 18% of 100m of the fairway width, and 34%~43% of 1L of ship's length. By applying the result into the current audit system using $8L{\times}3.2L$, $6L{\times}1.6L$, we found that there is big difference with $3.5L{\times}1.5L$ in Japan, $5.9L{\times}2.2L$ in Shanghai, $4L{\times}5B$ in Denmark, and $3L{\times}2L$ in Jinhae, Korea. For this reason, further studies should be carried out in near future to the area mostly affected by congestion.

• Geophysics and Geophysical Exploration
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• v.18 no.4
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• pp.181-196
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• 2015

A 3.5 kHz or chirp sub-bottom profiling survey is widely used in the marine geological and engineering purpose exploration. However, swells in the sea degrade the quality of the survey data. The horizontal continuity of profiler data can be enhanced and the quality can be improved by correcting the influence of the swell. Accurate detection of sea bottom location is important in correcting the swell effect. In this study, we tried to pick sea bottom locations by finding the position of crossing a threshold of the maximum value for the raw data and transformed data of envelope or energy ratio. However, in case of the low-quality data where the sea bottom signals are not clear due to sea wave noise, automatic sea bottom detection at the individual traces was not successful. We corrected the mispicks for the low quality data and obtained satisfactory results by picking a sea bottom within a range considering the previous average of sea bottom, and excluding unreliable big-difference picks. In case of trace by trace picking, fewest mispicks were found when using energy ratio data. In case of picking considering the previous average, the correction result was relatively satisfactory when using raw data.

• Korean Journal of Health Education and Promotion
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• v.19 no.3
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• pp.73-85
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• 2002

This study was conducted to examine community residents' knowledge level and related factor on electronic wave in order to provide basic data for development of education and publicity program. 2,000 people, who lived in five big cities and five small and medium cities, were selected ad subjects of this study. The data were collected from May 1, 200 I to August 31, 2001. The results of this study are as follows. According to the average knowledge level of harmful affect of electronic wave on health in general characteristics, female was higher(37.40 ± 5.24 points) than male; ‘forties’ was highest(37.77 ± 5.69 points); ‘married spouse’ was high(36.84 ± 5.59 points); ‘living in small-ta-medium city’ was high(36.84 ± 5.32 points). ‘university graduate’ was highest(37.41 ± 5.32 points) in education level, ‘middle class’ was high(36.61 ± 4.96 points) in economic status, ‘professional technician’ was higher(36.68 ± 6.55 points) than other occupations in occupational type. According to the knowledge level of harmful affect of electronic wave on health in health condition by self-judgment, ‘good health condition’ was highest(36.77 ± 4.99 points). In the case of the knowledge level of those who visited medical institutions for last one year, ‘never visited’ was highest(37.19 ± 5.02 points). In the kind of medical institutions, ‘those who visited general hospital’ was highest(36.58 ± 5.63 points). In the way of knowledge obtainments of electronic wave through education and publicity media, ‘school education’ was highest(37.55 ± 5.19 points). According to the score of awareness level of disease incidence related to electronic wave, allergy and erethism was highest(57.8 points on the basis of 100 points). It appeared in order of leukemia, skin disease or skin cancer, dementia, various cancers, cataract, and brain tumor. The variables which significantly influenced knowledge level of harm of electronic wave were knowledge obtainments of electronic wave, age, economic status, daily TV watching period, sex, period of daily cellular phone use, period of working with computer, and daily VTR watching period. The knowledge of community residents concerning harmful affect of electronic wave on health is needed because people's opportunity of exposing to electronic wave is increasing. Especially, it is the demands of the times to provide information on knowledge of each equipment which generate electronic wave. The government, the product manufacturing companies, related social organizations, and education institutions must make efforts to develop the education program which is needed to make people have right knowledge and attitude.

• Environmental Mutagens and Carcinogens
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• v.26 no.4
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• pp.119-124
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• 2006

There are $10{\sim}30%$ polyphenol and $2{\sim}4%$ caffeine in green tea. Caffeine is a kind of alkaloid containing nitrogen which cause stimulation, impatience, headache, insomnia, low birth weight infant. Because of these negative effect, decaffeined beverage came out and decaffeined coffee already have a big market since 1970s. Having proving the physiologic functions of green tea, high consumption of coffee is shifting to green tea. Because of the carcinogenic effect of the organic solvents, decaffeine processing with supercritical carbon dioxide has industrialized and have an advantage in environment-friendly and minimized flavor loss. Decaffeined green tea using supercritical carbon dioxide is considered to be safe but there are not enough study. We investigated the chromosome aberration test with mammalian cell line, CHL. When the cells were treated with 5000, 2000, 1000 ${\mu}g/ml$ and compared with the negative controls, there were no significant(P>0.05) increased chromosome aberration. Same results was observed when adding S9 mixture or not. As a result, water extract of decaffeined green tea using supercritical carbon dioxide does not induce chromosome aberration.

• Journal of the Korean Data and Information Science Society
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• v.28 no.4
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• pp.831-841
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• 2017

The irrational number ${\pi}$ is defined as the ratio of circumference of a circle to its radius and always becomes constant. This article does Monte Carlo approximation of its value using the famous Buffon's needle experiment and shows that its convergence is not always proportional to the sample size. We also do Monte Carlo simulations to see the convergence of the computed ${\pi}$ values from the random walk series with independent normal increment. Finally we apply the theoretical derivation to various financial time series data such as KOSPI, stock prices of Korean big firms, global stock indices and major foreign exchange rates. The historical data shows that log transformed data random walk process but most of their first lagged data don't follow a normal distribution. More importantly the computed value from the ratio of the regression coefficient ${\pi}$ tend to converge a constant, unfortunately not ${\pi}$. Using this result we could doubt on the efficient market hypothesis, and relate the degree of the hypothesis with the amount of deviation of the estimated ${\pi}$ values.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1259-1266
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• 1998

To clarify the values and varieties of the buckwheats as a dietary source of nutritional and functional components, thirteen different samples of buckwheat were analyzed for this investigation. Six developed seeds were given by RDA, Korea or RDA branch of Kangwondo, and seven land race seeds were collected from a farmhouse. Amino acid analysis showed that glutamate, arginine and asparagine were major amino acids, whereas tryptophan, methionine and cysteine were minor ones of buckwheat. In addition, tryptophan content of buckwheat cultivars from Korea was 195 mg% on average. The content of rutin tended to be higher in developed cultivars than land races. On the other hand, the contents of phytic acid in buckwheats were in the range of 7.0 to 13.6 mg/g. In the tocopherol homologues of the buckwheats analyzed by HPLC, mean ${\gamma}-tocopherol$ contents were 6.16 mg/100 g with the actual range of $4.67{\sim}8.58\;mg/100g$, whereas ${\beta}-form$ was very low or zero. There were a big variations in the iron content of the buckwheats of the minerals. SDS-PAGE showed that total proteins from buckwheats exhibited a relatively similar electrophoretic patterns on the whole. The results show that CV Suwon 1 has good quality, judged from the distribution of the components of buckwheats analyzed.