• Journal of Korean Society of Transportation
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• v.25 no.1 s.94
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• pp.109-119
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• 2007

Increasingly, the emphasis in regional Passenger rail Planning is finding ways to more efficiently use existing facilities, with particular attention being Paid to Policies designed to spread Peak-Period travel demand more evenly throughout the week with consideration of train classification. In this context the individual's choice of time to travel is of crucial significance. This paper investigates the use of multinomial logit analysis to model ridership by rail classification using data collected for travel from Seoul to Busan during the one week in October 2004. The Particular model form that was successfully calibrated was the multinomial logit (MNL) model : it describes the choice mechanism that will Permit rail systems and operations to be planned on a more reliable basis. The assumption of independently and identically distributed(IID) error terms in the MNL model leads to its infamous independence from irrelevant alternatives (IIA) property. Relaxation of the IID assumption has been undertaken along a number or isolated dimensions leading to the development of the MNL model. For business and related rail travel patterns, the most important variables of choice were time and frequency to the chosen destination. The calibrated model showed high agreement between observed and Predicted market shares. The model is expected to be of use to railroad authorities in Planning and determining business strategies in the Increasingly competitive environment or regional rail transport.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.653-657
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• 2009

Nitrous oxide is a typical greenhouse gas which is produced from various organic or fossil fuel combustion processes as well as chemicals producing plants. $N_2O$ has a global worming potential of 310 times that of $CO_2$ on per molecule basis, and also acts as an ozone depleting material in the stratosphere. However, its removal is not easy for its chemical stability characteristics. Most SCR processes with several effective reducing agents generally require the operation temperature higher than $450^{\circ}C$, and the catalytic conversion becomes decreased significantly when NOx is present in the stream. Present experiments have been performed to obtain basic design data of actual application concerning the effects of $SO_2$ and $NH_3$ on the interim and long term activities of $N_2O$ reduction with CO over the mixed metal oxide (MMO) catalyst derived from a hydrotalcite-like compound precursor. The MMO catalysts used in the experiments, have shown prominent activities displaying full conversions of $N_2O$ near $200^{\circ}C$ when CO is introduced. The presence of $SO_2$ is considered to show no critical behavior as can be met in the $NH_3$ SCR DeNOx systems and the effect of $NH_3$ is considered to play as mere an impurity to share the active sites of the catalysts.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.2
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• pp.133-139
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• 2001

In order to obtain fundamental data for estimation of fisheries resource by echo sounder, we carried out the measuring of dorsal aspect Target strengths for rock bream and dusky spinefoot fishes that were caught much around the Jeju Island and in South Sea of Korea. The appropriate equations share the common form. TS=A+20 log L, where TS is the average dorsal aspect target strength in decibels, L is the fish total length in centimeters, and the coefficient A is determined by a least mean squares regression analysis. For rock bream, the result is TS=-72.97+20 log L and, for dusky spinefoot it is TS=-63.16+20 log L And, we have investigated the bearing range of maximum dorsal aspect target strength for all of rock bream and dusky spinefoot by the echo sounder with transducer of which frequency is 200kHz. They are $-12^\circ$-$-21^\circ$and $-1^\circ$--8 espectively, when the fishes is swimming down to the bottom. The maximum dorsal target strengths are -41.50dB at -18 or rock bream and -30.69dB at $-6^\circ$for dusky spinefoot.

• Korean journal of food and cookery science
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• v.30 no.5
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• pp.547-555
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• 2014

The purpose of this study is to understand consumer awareness and preference regarding rice cakes by surveying the awareness, preference, and consumption behavior of college students regarding rice cakes, and to survey their perception and usage of rice cakes, thereby using the results as basic data to establish measures to develop Korea's rice cakes. To sum up the study's results, the survey included both male (54.5%) and female (45.5%) subjects. Those aged "20 to 23" accounted for the largest share (67.9%) of total respondents, and those majoring in "humanities and social studies" comprised the largest portion (47.8%). A majority of the respondents resided in "small and medium-sized cities", and most either lived at home or lived away from their families. A majority of the subjects received monthly allowances ranging from 200,000 to 300,000 won. In order of awareness, the most well-known type of rice cake was "injeolmi (rice cake made from glutinous rice and coated with bean flour)", followed by "songpyeon (half-moon-shaped rice cake)", "garaeddeok (bar rice cake)", and "baekseolgi (steamed white rice cake)". The women were better aware of "injeolmi", "baekseolgi", and "garaeddeok" than the men, and "soemeoriddeok" was not commonly known among either gender. In terms of preferences for rice cakes, overall, the subjects liked "injeolmi" and "songpyeon" the most. However, certain differences were found in preferences for rice cakes between the men and women. The women exhibited higher levels of preference for "injeolmi" and "songpyeon" than the men. On the other hand, the men revealed higher levels of preference for "baekseolgi", "jeolpyeon", and "garaeddeok" than the women. The most common answer to important factors for popularizing rice cakes was "a diverse assortment of rice cakes", followed by "the development of creative technologies" and "the taste of rice cakes reflecting consumer needs", in order of importance. Among the important factors to popularize rice cakes, "the development of unique packaging containers for rice cakes" (p<0.05) and "the development of proper packaging materials" (p<0.05) showed statistically significant differences. In the survey of consumption of rice cakes, the most frequent answer to the question "why do you like rice cakes? was "their tastes are good" with 146 respondents, followed by "I have been eating them for long" with 115 respondents. To the question "when do you use rice cakes", the most frequent answer was "I use them in daily life" with 133 respondents, followed by "I use them at special events" with 115 respondents. The women were found to use rice cakes frequently in daily life, whereas the men used them frequently at special events. When asked whether they had the intention to use rice cakes as a meal substitute, 100 men answered that they had no intention, whereas 96 women answered that they had the intention. When asked about the type of rice cake considered suitable for a meal substitute, the most popular answer was "injeolmi" with 108 respondents, followed by "baekseolgi" with 106 respondents.

• Journal of Korean Society of Transportation
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• v.26 no.6
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• pp.113-122
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• 2008

This study extended Park et al.(2007c), which analyzed the efficiency of a hierarchical transit network, showed the result of a real data, and analyzed its applicability. Operating cost was estimated using a model which was established in this study, and minimum transit demand was derived from the operating cost. The minimum transit demand value is just a sample calculation, thus it varies by many inside and outside factors of the model. Looking at the inside of the model, operating cost and travel speed are major factors, and the possibility of introducing urban subway becomes high when the operating cost of the transit system is low and its travel speed is high. As far as the outside factors are concerned, according to the analysis on the network structure, transit demand, and transit mode share, the minimum transit demand value which was derived in this study will be the maximum value among the possible values. In the feasibility study, the benefit is likely to be overestimated and the cost is likely to be underestimated than those of this study. It could be concluded that the methodology of a feasibility study is appropriate in the field standard. This study analyzed the efficiency of introduction of urban subway using analytical approach, thus has many shortcomings and limitations. However the practical approach, like feasibility study, has some limitations as well. This study could be a basis on establishing an analysis framework that is more accurate and reasonable by comparing analytical approach and practical approach.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.107-116
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• 2020

In this data paper, we share the dataset obtained during 2019 from the test-bed to develop soil moisture estimation technology for upland fields, which was built in Seosan and Taean, South Korea on May 3. T his dataset includes various eco-hydro-meteorological variables such as soil moisture, evapotranspiration, precipitation, radiation, temperature, humidity, and vegetation indices from the test-bed nearby the Automated Agricultural Observing System (AAOS) in Seosan operated by the Korea Meteorological Administration. T here are three remarkable points of the dataset: (1) It can be utilized to develop and evaluate spatial scaling technology of soil moisture because the areal measurement with wide spatial representativeness using a COSMIC-ray neutron sensor as well as the point measurement using frequency/time domain reflectometry (FDR/TDR) sensors were conducted simultaneously, (2) it can be used to enhance understanding of how soil moisture and crop growth interact with each other because crop growth was also monitored using the Smart Surface Sensing System (4S), and (3) it is possible to evaluate the surface water balance by measuring evapotranspiration using an eddy covariance system.

• The Journal of the Korea Contents Association
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• v.17 no.1
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• pp.337-350
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• 2017

As interactive digital signages with computer network have been increasingly popular in public space, the needs for studying content types and interactions suitable for the digital signages are emerging. In this study, we aim to find out what contents are preferred to share and how to interact in the digital signage installed in Seoul subway stations. We conduct a case study, a survey, and an in-depth interview. In the case study, we collect content types which have been communicated in public space. Among these content types, we conduct a survey to find out the preferred contents of Seoul citizens. We observe that the preferred contents differ by the age of the citizens. Specifically, 20's prefer the subjects about personal interests, 40's choose public interests and 30's prefer both types. In addition, we observe that the subjects about personal interest are relatively less preferred when people read, whereas the subjects are preferred when people write. Lastly, regarding interaction type, we find that Seoul citizens prefer touching the screen directly to using smart phone to express their empathy. The contents that people write and the number of likes will be archived as big data and analyzed so that Seoul city officers and citizens will know what people think based on age, location, and subjects.

• Journal of Korea Port Economic Association
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• v.31 no.3
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• pp.141-153
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• 2015

This paper is an attempt to analyze the comparative advantage of Busan Port to China. For this, we use the market comparative advantage index, which is a version of the revealed comparative advantage index. The market comparative advantage index (MCA) uses trade patterns to identify the sectors in which a region has a comparative advantage, in this case by comparing Busan Port's trade profile with the world average (China). The indices are calculated at the commodity level of the HS four-digit classification. The export data used in this study are obtained from the Korea International Trade Association. Exports to China accounted for almost one third of Korean exports in 2014. There are, however, structural differences among the main export items of Busan Port. This paper, therefore, employs MCA indices to reveal the behaviors of the ten main export items, which are "HS3920-other plates/sheets/film/foil of plastics," "HS7606-aluminum plates/sheets/strip," "HS8479-unspecified machines/medical appliances," "HS8486-machines for semiconductor devices or wafers," "HS8529-parts for transmission apparatus for television," "HS8703-motor vehicles for the transport of persons," "HS8708-parts of motor vehicles," "HS9001-optical fibers," and "HS9013-liquid crystal devices." The study shows that export competitiveness of nine items increases, the exception being HS8703. However, China's import ratios of seven of the nine items for which the MCA indices go up are on the decrease, which means that it would be hard to expand the export market for these seven items, despite the higher MCA indices. Since the shares of the port's total exports to China of HS3907, HS8486, HS8529, HS9001, and HS9013 in total exports to China increase together with China's import ratio decreasing, these items may have promising export markets. MCA increases of HS7606 and HS8479 are attributable to China's lower import ratio, rather than a higher export share, so higher MCA indices do not guarantee higher export competitiveness for these items.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.103-112
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• 2011

Aquatic contamination by organic pollutants has been a suspected reason for rapid decrease of amphibian populations whose embryonic and larval stages are in an aquatic environment. Amphibian embryos can be a useful model to study the ecoctoxicologial impacts of aquatic pollutants. The obtained toxicological data are useful references for the management of aquatic pollutants in public health because amphibia share many developmental events with terrestrial vertebrates including humans. Safety guidelines for the toxicological effects of aquatic contaminants of chemicals identified as hazardous should be addressed at multiple endpoints. Alkylphenols have been widely-used in agricultural, industrial, and household activities; they contaminate and can persist in aquatic environments. Exposure to alkylphenols results in endocrine disruption in aquatic animals. In this review, we summarize the developmental toxicities of alkylphenols in amphibian embryos and larva according to the exposure route, chemical concentration, duration of exposure, and affected developmental stage together with mechanisms of toxicity and typical patterns of developmental abnormality. The merits of amphibian embryos as a toxicity test model for mid- to long-term exposure to aquatic pollutants are discussed proposed.

• The Journal of the Korea Contents Association
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• v.8 no.8
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• pp.128-146
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• 2008

Cyworld has created a new social phenomenon that relationship between people and communities could be built by committing to digital writing. It has altered the way of people's writing attitudes from self-confessed to self-describing and self-broadcasting ways in which one regards oneself as the center of the cyber world. The purpose of this paper is to identify the shift in one's writing attitudes and how he/she develops technologies of the self in the Cyworld space. Quantitative and qualitative methods support the result; The analysis of 100 Cyworld users' mini-homepages show how the visual images in Cyworld affects their way of digital writing and the analysis of the change of writing habit due to sharing data how virtual 'family' that has been created by Cyworld. I categorize the characteristics of digital writing into three; 1)Visualization of technologies of the self 2)Networked technologies of the self 3)Sharing secretes. The aim of writing in Cyworld is not to keep the secrete but to share and, eventually, texts are circulated in the networked society where one is participated(Cyworld family). Therefore, the usage of images plays a significant role in Cyworld communities because the opened secretes are usually prepared to be presented on the basis of trustworthy toward other members.