• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.70.1-70.1
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• 2017

We reexamine the Goryeosa (History of the Goryeo Dynasty, A.D. 918-1392) account that Halley's Comet was seen during the daytime on September 9, 1222. To verify whether the referenced "daytime" refers to twilight or daylight (i.e., when the Sun is above horizon), we determine the absolute magnitude and heliocentric power-law exponent for Halley's Comet using observations made around the perihelion in 1986 and a formula considering the brightness enhancement by forward-scattering. We then apply the results to estimate the light curve of Halley's Comet in the 1222 event and find that the total visible magnitude could reach a maximum of -1.7 on September 8, one day before the Goryeosa's account. Therefore, we think that Halley's Comet with a coma of -1.7 mag and tail-length of about $20^{\circ}$ was actually observed during the day on September 9 because the observational conditions on that day were so good that Venus was visible in daylight. Furthermore, we think that the event might have been witnessed in the morning sky because the contents of Venus's culmination (occurred around September 9.07 TT) continue on the same day account.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.173-178
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• 2016

Many studies have been carried out on monitoring the target by cooperating a drone with remote sensors recently. This monitoring system uses static sensors to measure environmental data and drones to collect measured data. In geotechnical engineering, inspectors go around measuring the safety of construction site and it is impractical to compose a network among numerous sensors in terms of the cost efficiency. In this paper, we propose a data collection system based on interaction between a drone and a few sensors that are installed around the target structure for geotechnical projects. Through experimental results, we also verify the availability and the time and cost efficiency of the proposed system comparing with using inspectors.

• International Journal of Automotive Technology
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• v.4 no.2
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• pp.101-108
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• 2003

There are a lot of factors that influence automotive fuel economy such as average trip time per kilometer, average trip speed, the number of times of vehicle stationary, and so forth. These factors depend on road conditions and traffic environment. In this study, various driving data were measured and recorded during road tests in Seoul. The accumulated road test mileage is around 1,300 kilometers. The objective of the study is to identify the driving patterns of the Seoul metropolitan area and to analyze the fuel economy based on these driving patterns. The driving data which was acquired through road tests was analysed statistically in order to obtain the driving characteristics via modal analysis, speed analysis, and speed-acceleration analysis. Moreover, the driving data was analyzed by multivariate statistical techniques including correlation analysis, principal component analysis, and multiple linear regression analysis in order to obtain the relationships between influencing factors on fuel economy. The analyzed results show that the average speed is around 29.2 km/h, and the average fuel economy is 10.23 km/L. The vehicle speed of the Seoul metropolitan area is slower, and the stop-and-go operation is more frequent than FTP-75 test mode which is used for emission and fuel economy tests. The average trip time per kilometer is one of the most important factors in fuel consumption, and the increase of the average speed is desirable for reducing emissions and fuel consumption.

• International Journal of Human Ecology
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• v.5 no.1
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• pp.23-34
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• 2004

This paper outlines the findings of a consumer survey conducted in 1996 and 2001 by the University of Bonn, Germany, across 15 European countries. The survey involved a sample of 3,300 respondents in 1996 and around 11,000 respondents in 2001, throughout all 15 EU countries. Children and adolescents between the ages of 10 and 17 were surveyed on their consumption habits and their attitudes towards the environment. The paper outlines the key findings on "the process of socialization with money". Children come to appreciate the importance of money even before their first day at school. Even young children know you sometimes need cash to fulfil dreams. But the chance to experiment with money for real only comes when children first receive pocket money, usually from their parents. Later, in adolescence, consumer pressure starts to make an impact and it becomes more difficult to make ends meet. Spare time or holiday jobs help top up pocket money and enable adolescents to keep out of debt. This paper reports on a long term comparative study throughout the European Union among children and adolescents, analysed by country, age group and gender. The paper discusses the places young consumers can turn to in trying to fulfil their growing consumer needs. It also examines how much money is at their disposal. It then concludes by considering the influence of "financial socialization" on how young people deal with money.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.41.2-41.2
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• 2014

Hierarchical merging scenario indicates that galaxies go through major and minor merger events during their formation and evolution. As a result of the merging, substructural features of remnants such as stellar stream are shown around a current galaxy system. To find evidence of stellar substructures on M31 system, we used the near-infrared images of JHK filters obtained from the Wide Field Camera (WFCAM) at UKIRT 3.8m. A total sky coverage is an area of about$ 4.5^{\circ}{\times}6^{\circ}$ around M31. Indeed, M31 system which consists of several satellite systems contains stellar substructures such as giant stellar stream, loops, and spurs. By analysing stellar populations on the near-infrared color-magnitude diagrams, we selected member star candidates of each stellar substructure, from which we map out spatial distribution of stars in the vicinity of M31 system. Here, we present spatial density distribution maps of stars on each substructure over the entire field of M31 system. Also, we discuss the possible origin of the substructures and the implications on the galaxy assembly process.

• Publications of The Korean Astronomical Society
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• v.34 no.3
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• pp.49-65
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• 2019

We investigate the provenance and the changes in the timekeeping system focusing on official records such as almanacs and textbooks published by the government after the solar calendar was introduced. We found that the solar calendar and the 12-hour clock time first appeared in 1884 during Joseon dynasty, at that time the solar calendar was used at the open port in Busan to facilitate the exchanges with Japan. The 12-hour clock time first appeared in the 『Hansung Sunbo』 published by the government in 1884. We also found that the Joseon dynasty also used 12 diǎnzhōng or 12 diǎn. In addition, the term of the 'Sigan' first appeared in the first official academic textbook in August 1895, and the chapter related to time contained the information about 12-hour clock time instead of the 12 Shi. In 1908, the meaning of the solar time, the equation of time, and the differences in longitude with the adoption of Korean Standard Time were introduced. Meanwhile, the 24-hour clock time was first introduced in Joseon and applied to railway times in 1907. The 1946 almanac, the first issue after liberation, used the 12-hour clock time which uses 'Sango', 'Hao' and the 24-hour clock time started to be used from the following year and is still used to this day. Finally, the 12-hour clock time, which was introduced around 1884, was enacted as Article 44 of the law in 1900 and was revised again in 1905 and 1908. In Korea, the terms related to the time in the current astronomical calendar system were newly defined around 1884, 1896, and 1908, and gradually standardized through the establishment of laws.

• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.402-406
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• 2016

In order to investigate the thermal stability of electro-conductive poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT/PSS), we have prepared films by casting PEDOT/PSS aqueous solution without using a binding material and measured surface resistances of the films while annealing at $200^{\circ}C$. Electrical properties of films were improved by annealing, and the maximum conductivity ($540S{\cdot}m^{-1}$) after annealing for 2 hrs was found to be approximately 3 times higher than that ($180S{\cdot}m^{-1}$) of the original film. The conductivities, however, dramatically decreased with an increase in annealing time and dissipated after 24 hrs of annealing. On the other hand, PEDOT/PSS films hybridized with graphene oxide (GO) displayed a salient improvement in conductivity by annealing, which was measured to be around $600S{\cdot}m^{-1}$ even after 30 hrs of annealing at $200^{\circ}C$. We tentatively conclude that hybridization with GO enhances the thermal stability of PEDOT/PSS.

• Journal of Families and Better Life
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• v.23 no.4 s.76
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• pp.79-89
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• 2005

This study was conducted to encourage dissatisfied consumers to initiate an active complaining process over beauty salon services as well as to reduce consumer dissatisfaction at the time of using such services. A questionnaire survey was conducted with female consumers over the period between December 1 and December 20, 2004. A total of 753 questionnaires were used for the final analysis. The following findings were obtained: 1. Consumer dissatisfaction index with beauty salon services was 23.02 (65.77/100) and the respondents showed the highest level of dissatisfaction with the price. 2. The level of complaints about beauty salon services was very low, as shown by the index value 7.12 (25.43/100). Most of the respondents simply did not go back to the particular beauty shop, or complained privately to people around them when they felt dissatisfied with beauty service. 3. Benefit awareness and level of dissatisfaction had the greatest effect on the complaint behavior about unsatisfaction beauty salon services.

• Korean Journal of Artificial Intelligence
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• v.7 no.1
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• pp.13-16
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• 2019

While the Chinese banks have started the impact of foreign banks. At the same time, rising pressure on foreign exchange reserves and appreciation of the renminbi has prompted Chinese banks to go abroad and diversify their risks. The financial crisis of 2008 has caused the continued turbulence of the major financial markets around the world, and the valuation of foreign financial institutions has been drastically shrinking, providing opportunities for Chinese banks to carry out overseas M&A. Based on the overseas M&A status of Chinese commercial banks, this paper sums up the characteristics of the overseas M&A. Then taking a series of overseas M&A conducted by ICBC from 2006 to 2011 as an example, it analyzes the relationship between M&A and performance growth using grey incidence model. The test shows: there is a positive correlation between both overseas M&A and interest rate differential with performance growth of ICBC, and overseas M&A transactions role in promoting the performance growth is significantly higher than the interest rate differential.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.3-10
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• 2005

Since in 1970, the length of concrete pavements(JCP, JRCP and CRCP) are growing rapidly at both of main highways and local roads. Many of them are deteriorated and old enough to be repaired or replaced. The pavement is more important than the other infrastructures and it is very difficult to go around or block the traffic during the rehabilitation. The very-early strength latex-modified concrete(VES-LMC)may offer the advantages of high-early-strength, higher flexural strength, higher bond strength, and improved durability. The VES-LMC could be used at a kind of fast track ofr early opening to the traffic after 3 hours of concrete placement. The installation of VES-LMC overlay at Jung-Boo highway was successfully done from April 28 to 29, 2005. The traffic was closed at 07:00 PM and opened to traffic at 08:30 AM. The compressive and flexural strength of VES-MC were more than 28MPa, 6.2MPa after 4 hours, respectively.