• Journal of the Korean Society for Library and Information Science
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• v.41 no.4
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• pp.93-111
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• 2007

The Internet is now an integral part of the everyday lives of a majority of people. Web users are becoming increasingly skeptical of the information and services offered online. They are demanding web sites that offer credible information. This study focused on what features of web sites affect the perception of web credibility. For this purpose, I took the responses from 648 people and extracted 49 factors that affect web credibility. I placed the individual factors - the specific questions asked in the survey - into one of four categories expertise. trustworthiness, ads and other and calculated the means for each of the 49 factors. As a result, 29 out of 49 factors increase the Perceptions of credibility and 20 factors decrease the web credibility. Sites with frequently update. the credentials of authors, strict content guides, search capabilities, clear connections to the real world fared good in credibility. Technical problems such as broken links, site sown, or typographical errors were rated the most negative on this scale On the other end of the scale, a domain name that ends in' .org' or' .or.kr' caused little change in perception of credibility.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.12
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• pp.950-958
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• 2013

The Lunar orbiter is expected to be inserted into a ~300km low Earth orbit using Korea Space Launch Vehicle-II(KSLV-II). After the states are successfully determined with obtained tracking data, the Trans Lunar Injection(TLI) burn has to be done at appropriate epoch to send the lunar orbiter to the Moon. In this study, we describe in detail the mission scenario of the Korean lunar orbiter from the launch at NARO Space Center to lunar orbit insertion(LOI) stage following direct transfer trajectory. We investigate the launch window including launch azimuth, delta-V profile according to TLI and LOI burn positions. We also depict the visibility conditions of ground stations and solar eclipse duration to understand the characteristics of the direct transfer trajectory. This paper can be also helpful not only for overall understanding of ${\Delta}V$ trend by changing TOF and coasting time but for selecting launch epoch and control parameters to decrease fuel consumption.

• Clean Technology
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• v.24 no.3
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• pp.166-174
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• 2018

Since particulate matter has high impacts on human health and everyday life, the dual fuel systems utilizing diesel and compressed natural gas have been developed to improve the environmental performance of diesel vehicles. The objective of this study is to estimate the economic feasibility of the dual fuel system based on real operating data of dual fuel buses and diesel buses. The system is economically feasible if the annual mileage of the dual bus is higher than 30,000 km, or if the unit fuel price of diesel is higher than that of CNG by 408 won. The uncertainty analysis results show that the economic feasibility of the system is probabilistically high, regardless of the variability of input data such as mileage and unit prices for the fuels. The sensitivity analysis results show that diesel and CNG prices are the highest contributor to the net present value of the system. Based on these results, economic incentives are suggested to disseminate the systems. This study would provide valuable economic information for bus business industry and policy maker to help make decisions for applying and disseminating the dual fuel systems to mitigate particulate matter problems.

• Journal of Wetlands Research
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• v.9 no.3
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• pp.43-49
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• 2007

A ditch is a facility for managing washed-off runoff from parking lot area. Washed-off runoff inflows into ditches where it is retained for a short period of time. At this point, it is assumed that a ditch is a preliminary unit for runoff treatment. This research carries out the distribution of particle size and chemical compound for sediment in parking lot ditch. This work is important to understand the amount of generated sediment from this area to be able to determine different particle size ranges for treatment. Metal concentrations for sediment according to particle size are analyzed. From the distribution of particle size, the weight ratio with the range of $425-850{\mu}m$ is the highest. Considering its weight ratio, the metal concentration of coarser particles is high, otherwise metal concentration increases as particle size decreases. Metal load of the range is higher and the ratio of total metal load in the case of Cu, Pb, Zn is nearly 30%. Moreover metal concentration associated with particle size depends on particle ratio. To manage non-point source pollution for parking lot area, these results can be used with this ditch unit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.703-709
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• 2017

Korea Utility Helicopter(KUH) is a project to replace the aging helicopter presently being operated by the military with a domestic helicopter. The auxiliary power unit is a device that supplies emergency power to the system by an alternator installed when the main generator fails and the start motor converts the electrical energy of the battery into mechanical rotational energy to rotate the auxiliary power unit engine. With continuing power and operation, defects of the starting motor were found and improvements were carried out to solve it. In the failure mode analysis, the causes of possible defects were classified into 5 categories. Analysis of the 5 factors revealed that the main cause of defects is mechanical wear, which was found to be related to spring pressure. 250 tests were conducted through the theoretically determined pressure and regression analysis was performed with 4 sampling.The results showed that pressure was related to wear rate. In conclusion, early wear and breakage due to wear can be controlled through spring force and test showed the prediction of wear and the validity of the result were confirmed.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.717-726
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• 2017

The current allowable cross-contamination level of fatty acid methyl esters (FAME) in aviation turbine fuel (AVTUR) is 50 mg/kg, due to that the presence of FAME in AVTUR can significantly impact the fuel supply system and jet engine. It has been difficult to analyze the level of FAME in AVTUR, since it is consisted of a lot of hydrocarbons. In this study, thus, a new method using multi-dimensional GC-MS (MDGC-MS) was proposed in order to determine the FAME level in AVTUR effectively. Applying to MDGC-MS with Deans switching system enabled us to detect and quantify the FAME with low carbon numbers such as those derived from coconut oil and palm kernel oil. The matrix effect of MDGC-MS method, which could shift the FAME peaks to slightly longer retention times, was reduced by 20 times compared with that of 1-dimensional GC-MS reference method. This developed method could be suitable for qualitative and quantitative analyses to determine the contamination level of trace FAME in AVTUR.

• Journal of the Korea Convergence Society
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• v.13 no.2
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• pp.177-183
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• 2022

This study investigated through eye tracking what gaze path the audience searches through portal sites (Naver, Daum, Zoom, and Nate). As a result of the layout analysis according to the gaze path of the search engine, the four main pages, which can be called to be the gateway to information search, appeared in the form of a Z-shaped layout. The news and search pages of each site use an F-shape, which means that when people's eyes move from top to right in an F-shape, they read while moving their eyes from left to right(LTR), which sequentially moves to the bottom. As a result of analyzing through the heat map, gaze plot, and cluster, which are the visual analysis indicators of eye tracking, the concentration of eyes on the photo and head copy was found the most in the heat map, and it can be said to be of high interest in the information. The flow of gaze flows downward from the top left to the right, and it can be seen that the cluster is most concentrated at the top of the portal site. The website designer should focus on improving the accessibility and readability of the information desired by the user in the layout design, and periodic interface changes are required by investigating and analyzing the tendencies and behavioral patterns of the main users.

• Journal of the Korean Institute of Gas
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• v.14 no.1
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• pp.21-27
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• 2010

In the past vaporized gases from a carrier were burned or used for fuel. Due to the movement of bigger LNG carriers and using diesel engine, it is limited that ways of deposing vaporizes gases from the carrier by the act of environment. For getting over the problem, a reliquefaction process is considered. Even though the reliquefaction process was created to three generation process, it has been researched and developed to optimize the process. Basically the reliquefaction process is compartmentalized into Reverse Brayton Cycle System and Claude Cycle System. This research is focused on the reliquefaction efficiency with the systems and changing equipments arrangement by using HYSYS. The result could be use for a design of a reliquefaction process.

• Information Systems Review
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• v.12 no.1
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• pp.131-144
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• 2010

To survive in the rapidly changing business environment, it is very important for companies to respond to the changing environment effectively as well as agilely. As an approach to appropriately respond to the changing environment, companies have developed and exploited various business rules and related knowledge and attempted to implement them through information systems. However, most of legacy information systems used in companies have suffered from the limitations that do not properly utilize and systematically organize the business rules. This study proposes an introduction of BRE (business rule engine) as a solution to cope with the limitations and explores its effect on organizational agility based the case analysis of "W" Investment and securities Co., Ltd.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.924-941
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• 1998

It is not easy to access to the required data from the Web by using search engines because there are too many data selected and they do not provide enough information related to the corresponding data. Metadata is data about data. It includes information about data itself and contents of data as well. Users can acquire enough information about the corresponding data and access to the required data exactly using metadata, and therefore the data usability will be increased. In this paper, several metadata technologies and metadata models that are already in process of standardization or adopted as standards are analyzed, and the SeriCore Metadata Model for documents such as papers, project reports, technical reports, abstracts, and manuals, and graphic images that are in the field of science technologies on the Web is proposed. The SeriCore Metadata Management System that can generate, store, and retrieve metadata effectively is designed and implemented based on the SeriCore Metadata Model.