• Bulletin of the Korean Chemical Society
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• v.28 no.1
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• pp.53-58
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• 2007

In the dehydrogenation of ethylbenzene to styrene, CO2 could play a role as an oxidant to increase conversion of ethylbenzene and stability as well over TiO2-ZrO2 mixed oxide catalysts. TiO2-ZrO2 catalysts were prepared by co-precipitation method and were characterized by BET surface area, bulk density, X-ray diffraction, temperature programmed desorption of NH3 and CO2. These catalysts were found to be X-ray amorphous with enhanced surface areas and acid-base properties both in number and strength when compared to the respective oxides (TiO2 and CO2). These catalysts were found to be highly active (> 50% conversion), selective (> 98%) and catalytically stable (10 h of time-on-stream) at 600 oC for the dehydrogenation of ethylbenzene to styrene. However, in the nitrogen stream, both activity and stability were rather lower than those in the stream with CO2. The TiO2-ZrO2 catalysts were catalytically superior to the simple oxide catalysts such as TiO2 and ZrO2. The synergistic effect of CO2 has clearly been observed in directing the product selectivity and prolonging catalytic activity.

• The Journal of Fisheries Business Administration
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• v.33 no.1
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• pp.1-18
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• 2002

The observer program is being utilized In various fishing areas and fisheries internationally and nationally due to the its expected effectiveness in fisheries management and the collection of bioeconomic data necessary in fisheries management policy. The timely gathered data by observers play substantially a major role in decision-making fisheries policy such as the change in management measures, the application of season closure and area closure and etc. The expected effectiveness of the observer program In fisheries management, generally mentioned, is that it would lead to the increase in stock size from which the level of harvest would consequently increases. This study is aimed to analyze this tentatively expected effectiveness of the observer program in fisheries management. The changes in stock size and the level of harvest over time are analyzed under the observer program assuming the fishermen bear the cost of the observer program by investigating the change in fisherman's fishing activity under the observer program and by combining this changed activity with the biological model. The level of fishing efforts of fishermen was decreased from the results of the increase in fishing cost caused by the observer cost and the decrease in catchable stock size restricted by observers. This reduced level of fishing efforts enables stock size to increase over time and therefore, the expected level of harvest increases as time goes on. Another benefit under the observer program is to reduce management costs from the fact that fishermen are responsible for the cost of the observer program and the avoidance cost of fisherman responding to the fisheries regulation could be eliminated from the surveillance of observer. Therefore, it may possible to accomplish the cost-efficient fisheries management policy.

• Journal of the Korea Society of Computer and Information
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• v.19 no.6
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• pp.139-149
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• 2014

Much research has been conducted in educational robot, a new instructional technology, for K- 12 education. Several studies have shown that educational robot provides effective learning opportunities for students in both content areas of STEM(science, technology, engineering, and mathematics) and critical academic skills, such as collaboration, problem solving and communication skills. However, most studies to date on applications of educational robots have been conducted outside the formal education setting. This study analyzed the influence of using robots in an elementary school science class in Korea with regard to science learning motivation. A total of 121 students in fourth and fifth grades participated in the study. The experimental group was taught using robots in the science class, while the control group was taught using traditional methods. Analysis of covariance (ANCOVA) was conducted to compare the between-group differences in learning motivation before and after the experiment; an interview was also conducted for the experimental group. The study results showed a significant improvement (p<.05) in both learning motivation in the experimental compared with the control group. There was also positive response to learning with a robot. This study will play an important role in research on the use of educational robot in formal education in the future.

• Journal of Periodontal and Implant Science
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• v.30 no.1
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• pp.203-212
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• 2000

Putrefactive activity within the oral cavity is the principal cause of halitosis. The most common intraoral sites of oral malodor production are tongue, interdental and subgingival areas. The other foci may include faulty restorations, sites of food impaction and abscesses. Periodontal disease frequently involves pathological oral malodor, which is caused mainly by volatile sulfur compounds(VSC), such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide. The purpose of this study is to evaluate the association between oral malodor and periodontal status. Volatile sulfur compounds in mouth air were estimated by portable sulfide monitor($Halimeter^{TM}$). The results were as follows : 1. The levels of volatile sulfur compounds were significantly greater in a periodontitis group than in a control group(P<0.01). The amounts of VSC in mouth air from patients with periodontal involvement were four times greater than those of the control group. 2. The significant positive correlation was found between VSC concentrations and the number of pocket depth above 4mm(P<0.01), but correlation between VSC concentrations and plaque score was not statistically significant(P>0.05). 3. In the periodontitis group, VSC concentrations of pre-treatment significantly decreased after scaling and root planing(P<0.01). 4. No statistically significant correlation was found between VSC concentrations and sex / age in the periodontitis group. The above results indicate that periodontal disease may play a role as an important factor of oral malodor and deep periodontal pockets are a source of volatile sulfur compounds.

• Journal of the Korean Solar Energy Society
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• v.23 no.2
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• pp.21-34
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• 2003

This study aims to present the applicability of wind turbine generator system to urban buildings for the utilization of clean renewable energy. The results are as follows; According to the wind resource analysis, it has been found that small sized wind power system can be viable for buildings application due to the amplification of wind velocity around buildings or building clusters, in spite of low mean velocity of 2-3m/s in Seoul and Kyunggi urban areas. But planners must perform micrositing analysis around building so that wind turbine can be located at high velocity zones. The system must be designed to avoid obstacles preventing prevailing wind in buildings. It should be recognized that wind speeds are changing depending on the height and length from buildings. The wind power system can be used as a symbol of landmark which shows a sustainable architecture from the scenary Itself A case study for apartment building in urban showed that wind power systems can be applicable in two kinds of place, rooftops and ground levels. Especially, the wind power systems must be carefully positioned so that wind resources do not decrease when it is installed at ground levels. and according to life cycle cost analysis, adaption of new small win4 power systems to buildings were proved to produce a profit if it is considered the expense of environment improvement and the wind speed increasing according to rise of building height. This research will ultimately achieve green architecture that preserves nature and at the same time provides pleasant environment to humans, and will play a great role in establishing the environment-preserving sustainable architecture of the 21th century.

• Asian Journal of Atmospheric Environment
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• v.2 no.2
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• pp.81-89
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• 2008

The numerical simulation of wind and ozone ($O_3$) transport in mountainous regions was performed with a computational fluid dynamics technique. A dry deposition model for $O_3$ was designed to estimate $O_3$ deposition in complex terrain, and the qualitative validity of the predicted $O_3$ concentration field was confirmed by comparison with observed data collected with passive samplers. The simulation revealed that wind velocity increases around ridge lines and peaks of mountains. The areas with strong wind corresponded well with the sites of tree decline at high altitudes, suggesting that it is an important factor in the localization of tree/forest decline. On the other hand, there is no direct relationship between forest decline and $O_3$ concentration. The $O_3$ concentration, however, tends to increase as wind velocity becomes higher, thus the $O_3$ concentration itself may be a potential secondary factor in the localized decline phenomena. While the diffusion flux of $O_3$ is not related to localized tree decline, the pattern of advection flux is related to those of high wind velocity and localized tree decline. These results suggest that strong wind with large advection flux of $O_3$ may play a key role in the promotion of tree/forest decline at high mountain ridges and peaks.

• Journal of the Korean Institute of Rural Architecture
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• v.12 no.1
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• pp.9-16
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• 2010

As the importance of health and school health grows, the purposes of this research are to investigate the differences between the characteristics and the utilization of the nurse's office of an elementary school in an urban area and the nurse's office of an elementary school in a rural area, and to provide the data for the planning of construction of a nurse's office convenient for students to use after grasping the regional characteristics. The methods of this research include the interview and the survey conducted to the heath teachers after visiting 20 nurse's offices in 13 eups and myeons, and examined and analyzed the differences between the characteristics and the utilization of the nurse's office of elementary schools in an urban area and the nurse's office of an elementary school. The nurse's offices of the elementary schools in Cheongwon, a rural area, are worse in access to health care institutions and in the connection to the placement than those of the elementary schools in urban areas, so most of eups and myeons were not allowed for easy access to medical service. Depending on the bad personal surroundings of each elementary student, mental stress and the lack of heal care of each student should be taken care of along with the educating of the parents and the children. Also because of the difficulties in access to the health care institutions, it is suggested that a lot of support and interest should be provided for the nurse's offices and that a lot of changes with functions should occur to the nurse's offices so that the nurse's office of an elementary school can play the role as a local health care institution. Besides, the health teachers also should be able to provide more professional medical services by taking in-service training courses.

• Journal of the Korean association of regional geographers
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• v.15 no.1
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• pp.67-85
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• 2009

The Trans-Central Asian Railway consists of the Trans-Caspian Railroad, the Kazalinsk Route, the Turk-Sib, and the Trans-Kazakhstan Trunk Line. Currently, one-fifth of the residents in Central Asia are living around these railroads on which 70% of the economic activities in the region depends. The construction of the railroads in Central Asia was motivated by the Russian Empire's competition 'with its maritime rival, the United Kingdom, over the Eurasian heartland in a geostrategic sense. Using the railroads, the Russian Empire aspired to connect its central industrial regions in European Russia with the remote frontier areas in the Central Asian republics and to increase economic specialization of the region. After the breakdown of the USSR, however, the rail network, which had well been linked among the regions in the former Soviet nations, has been in a deteriorated linkage with their non-Soviet neighboring nations. Despite a lot of problems to be solved, the Trans-Central Asian rail network is expected to play a crucial role as a land bridge between East Asia and Europe as well as between Russia/the Baltic sea and the Indian Ocean/the Persian Gulf in the long-term.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.2
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• pp.242-253
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• 2005

The objective of this research is to identify and examine the punk hair styles which, with their various, rather vague names, help to describe the twentieth century subordinate culture or subculture and also their place today as one of the mainstream male hair trends. The scope of this research will stretch to include also: North-east and around that areas native Americans'hair styles which, are thought to have strong links with the Punk hair tend. The focus of this research will remain with the so-called Mohican or Mohawk hair styles(collectively referred to as Punk styles), which have originated mainly from native American warrions residing in North-east and South-east region of the United States. This study clarified a few questions in doubt concerning the origin of cockcomb hairstyle. Firstly, the cockcomb hairstyle known to represent punk hairstyle was influenced the American Indian's Roach style. Secondly, since Roach style is referred as Mohawk tribe's hairstyle in some refernces, the view of seeing cockcomb hairstyle as a Mohawk style is considered more persuasive. Thirdly, although Roach style was a usual hairstyle through North-east and South-east region of the United States, the people in South-east region did Roach hair style because of the North-east's influences. Lastly alike the Punkers had several kinds of cockcomb hairstyle. American Indians'Roach style also differed in shape concerning of their regions and their kindred. In addition, the reason why the most common term to refer punk hairstyle became Mohican is considered as that the film 'Last Mohican' has influenced on it. That film can appeal their history and play a good role of mediator to let the public know better about themselves, 'Mohican' naturally became the name of the specific hair style.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.30.2-30.2
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• 2010

It is a mistaken impression that the midlatitude ionosphere was a very stable region with well-known morphology and physical mechanism. However, the large disturbances of midlatitude ionospheric contents in response to global thermospheric changes during geomagnetic storms are reported in recent studies using global GPS TEC map and space-born thermospheric UV images, and its importance get higher with the increasing application areas of space navigation systems and radio communication which are mostly used in the midlatitudes. Positive and negative storm phases are used to describe increase and decrease of ionospheric electron density. Negative storms result generally from the enhanced loss rate of electron density according to the neutral composition changes which are initiated by Joule heating in high-latitudes during geomagnetic storms. In contrast, positive ionospheric storms have not been well understood because of rare measurements to explain the mechanisms. The large enhancements of ground-based GPS TEC in Korea were observed on 8 and 10 November 2004. The positive ionospheric storm was continued except for dawn on 8 November, and its maximum value is ~65 TECU of ~3 times compared with the monthly mean TEC values. The other positive phase on 10 November begin to occur in day sector and lasted for more than 6 hours. The O/N2 ratios from GUVI/TIMED satellite show ~1.2 in northern hemisphere and ~0.3 in southern hemisphere of the northeast Asian sector on 8 and 10 November. We suggest the asymmetric features of O/N2 ratios in the Northeast Asian sector may play an important role in the measured GPS TEC enhancements in Korea because global thermospheric wind circulation can globally change the chemical composition during geomagnetic storms.