• Journal of the Korean Society for Library and Information Science
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• v.46 no.2
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• pp.29-54
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• 2012

This study aims to grasp what factors affect users' recognition level and expectation level for library service, being offered at the library of Korea National Open University. Also, this study seeks to conduct a survey and analyze whether users' recognition level by library service dimensions has actually influenced the intention and the satisfaction with using the library. For this, it carried out the theoretical approach, which considers domestic and foreign documents on evaluation of quality of library service, and the empirical approach of questionnaire research and analysis. A research model was designed on the basis of LibQUAL+model to achieve the objective of this research. And the group-based difference was confirmed by carrying out verification on research hypothesis. As a result of analysis, the users' current recognition level by library service dimensions of Korea National Open University was indicated to have influence on the whole satisfaction with library and the continuous use intention. The whole satisfaction was indicated to have an effect on continuous use intention. Also, to enhance users' satisfaction level according to the behavioral characteristics of using library, the core elements for improving the library service of Korea National Open University were cited and these include improving the facility of library, implementing smart digital library system for offering remotely academic information, and securing diversity and currency of academic information sources such as printing materials and electronic materials.

• Journal of Animal Environmental Science
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• v.14 no.3
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• pp.159-166
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• 2008

This research was carried out to test and analyze capacity of the long distance sprayer fan in large livestock farmhouses. Long distance sprayer was manufactured to be able to spray a lot of water, which was a solvent for agricultural chemicals and black dye with the maximum spraying distance of 140 m and the effective spraying distance of 100 m. The spraying quantity and the distance were measured the intensity values of images within A4 papers, which absorbed the agricultural chemicals by spraying by binary image processing. These A4 papers were fixed upon the height of 1 m from soil ground at regular 10 m interval. After the A4 papers were collected and analyzed the intensity values of gray level. Gray level was ranged from 0 to 255, where 0 was black and 255 was white. A4 paper was fallen down from the stick at 10 m distance, because there were too large amount of sprayed water with black dye. Also, the paper showed low gray level at distance 30 m because of dropping lots of black water. The intensity value of gray level was showed almost less than 200 on the A4 papers between the distance 20 m and 100 m, which meant equality of spraying quantity. Additionally, it was possible to spay agricultural chemicals of until 180 m. Throughout this research, long distance sprayer could apply for preventing hoof-and-mouth disease in large livestock farmhouses.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.573-583
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• 2013

Construction of large-scale structures such as dams would be suggested actively to cope with change of flood characteristics caused by climate change. However, due to environmental, economic and political issues, dams are not ideally constructed. Thus flood damage reduction planning projects would get started including washland or detention pond for sharing the flood in basin. The washland made artificially by human being is an area of floodplain surrounded by bank to be intentionally inundated by overflowing through overflow structure adjacent to main channel during flood season. Flood reduction capacity at just downstream of each washland could be affected by type, length, and crest elevation of overflow structure in addition to shape of design hydrograph, storage volume of washland, etc.. In this study flood reduction effects of washland are estimated for overflow weir type and gate type to compare the results of flood reduction respectively subjected to given hydrograph in sample site, the Cheongmicheon stream. It has been shown that even if gate type at overflow structure could yield more flood reduction than overflow weir type, economic aspect such as initial cost, operation cost and maintenance cost should be considered to select the type of overflow structure because flood reduction rate by gate type could not be significant value from engineering point of view.

• Membrane Journal
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• v.28 no.1
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• pp.31-36
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• 2018

The purpose of this study is to investigate the changes of sludge characteristics according to the changes of influent sewage flowrate in the advanced wastewater treatment processes including MBR, SBR, and $A_2O$. The ratio of the actual sewage flowrate to the design flowrate is decreased from 100% to 70, 40%, and 10%, and the specific denitrification rate and ammonia oxidation (nitrification) rate was measured. The specific nitrification rate of the sludge collected from the aeration tank of each process was measured at a similar value ($0.10gNH_4/gMLVSS/day$) in all three process under the condition of 100% of sewage flowrate. It has tended to decrease significantly as the sewage flowrate decreased from 70% to 40%. The specific denitrification rate was also decreased by ~50% as the sewage flowrate decreased. However, considering the total nitrogen concentration in the influent and the microbial concentration in the reactor, the changes in kinetic parameter did not affect overall nitrogen removal. Therefore, it can be concluded that stable nitrogen removal will be possible under low influent flowrate condition if the MLVSS concentration is kept high.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.5191-5198
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• 2010

Although numerous studies have analyzed the relationship between subway travel demand (STD) and various characteristics of subway catchment area (SCA), a few studies examined the relationship between STD and the structure of pedestrian networks within each SCA. Hence, this study evaluates the structure of pedestrian networks within 79 SCAs in the city of Busan using Space syntax and investigates the relationship between STD and several characteristics of SCA including the spatial structure of pedestrian network. The analysis results show that the spatial integration of pedestrian networks within the SCAs, which represents the magnitudes of walking accessibility to subway station, is positively associated with STD among the three spatial indexes such as integration, connectivity, and intelligibility. In addition, the results show that STD significantly increases as the number of travel gathering facilities and the average floor area ratio within the SCAs increase. This study ultimately corroborates that designing the grid pedestrian network and assigning the travel gathering facilities to the compact buildings within SCAs are needed to ameliorate the spatial structure of SCA in the city of Busan as transit-oriented development system.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.6
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• pp.93-102
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• 2010

Existing web based information service system solutions show limitations in mobile information services, as well as problems such as uncertain error messages, and difficulty providing swift assistance or real time emergency support. In order to solve these deficiencies, a realtime wireless remote control system has been designed and implemented in this thesis, which is capable of managing and monitoring remote systems using mobile communication devices (Mobile Phone, PDA, Smart Phone) for realtime control. Proposed systems are applied at remote places, for instance 'office building', and a nursery school like 'kindergarten'. In the case of implemented at office building, it can be managing and controlling at real time all sorts of the sensor information that are installed at office building system environment through wire(web environment) or wireless(mobile device). In the other case at kindergarten system that are providing the real-time wireless remote control and monitoring system can be monitoring activity of kindergarten children with a mobile phone of authentication user. The security functions of proposed systems include mobile device user authentication and target system access control. The proposed systems allow real-time user authentication function and system access control function that improve the security of resource administrators and mobile device users, and provides not only uninterrupted services, but also real time mobile service environments.

• Journal of the Korean Geotechnical Society
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• v.18 no.1
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• pp.101-112
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• 2002

In this study, a new methodology fur the assessment of liquefaction potential is proposed and characteristics of the proposed methodology are verified. The experimental parameter of this methodology, that is, the plastic shear strain trajectory, is compared with the dissipated energy. It is shown that this parameter can express the liquefaction behavior which is generated by excess pore water pressure. This methodology takes advantage of the shear strain time history determined from the site response analysis based on the real time history of earthquake. In this site response analysis, shock type and vibration type records of similar predominant frequency are inputted. The liquefaction safely factors based on the proposed methodology and Korean detailed assessment related to the classical method are calculated from the results of the site response analysis and laboratory dynamic tests. Through this study, it is found that the proposed methodology can not only simulate the liquefaction behavior of saturated soils hut also express the seismic characteristics reasonably : leading type, predominant frequency, maximum acceleration, duration time.

• Journal of Navigation and Port Research
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• v.30 no.1 s.107
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• pp.53-59
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• 2006

Recently, 8,000TEU class containerships has started operating the shipping service and the mega-containership of over 10,000TEU is on planning. A unit cost in relation to shipping service is decreased by the bigger ship based on the economy of scale. Most of the previous studies have been performed and focused on the total operation cost from mega port to mega port. However, the purpose of this paper is to estimate economic efficiency of selected hub ports from point of view of total cost such as service cost(or operation cost), port charge and feeder cost, etc. First, the service-network of mega containerships is based on data of a domestic shipping company operated main line and economic analysis of individual scenarios on the cost and traffic when 10,000TEU mega containerships offer the services. The three scenarios presented in this paper set up the hub ports which are the port of Busan, Shanghai and Yokohama The results show that port of Busan is economically the most efficient one among others.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.1
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• pp.36-41
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• 2018

This paper presents an implementation of a millimeter-wave(W band) multiflare-angle horn antenna. The proposed antenna is a multimode dual-polarized square horn having equal E- and H-plane beamwidths and consists of a multimode generating section, a four-square-waveguide exciter, orthomode transducers, and power combiners for the sum pattern formation. The antenna structure has been designed to allow for easy fabrication and the designed antenna has been fabricated to a precision of ${\pm}0.02mm$ by layer-by-layer machining and diffusion bonding. The input reflection coefficient and the radiation pattern of the fabricated antenna have been measured using a network analyzer and a far-field test facility. Measurements show that the proposed antenna has 17.7~18.3 dBi gain, $25.2{\sim}28.5^{\circ}$ beamwidth, and an input VSWR between 1.02~1.75, within ${\pm}0.5GHz$ from the center frequency.

• Journal of the Korean Institute of Gas
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• v.18 no.1
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• pp.31-40
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• 2014

LNG storage outer tank is a vertically and horizontally prestressed concrete wall structure. Therefore, when the storage tanks become larger, prestressing tendons become longer and eventually the prestressing loss becomes larger. Also, recently, bomb terrors and accidental crashes have occurred frequently on important infrastructures. Therefore, LNG storage tanks are also exposed to these dangerous scenarios, where they need to be evaluated and protected from these threats. Therefore, in this study, the behavior of 270,000 kL LNG storage outer tank impacted by a flying object is evaluated using implicit FEM code, LS-DYNA. In the analysis, the prestress loss due to the increased length of prestressing tendons from enlargement of outer tank is considered. A comparison study between the LNG tanks with and without prestress loss is performed to investigate the impact behavior and the effect of prestressing force change on the safety and serviceability prestressed concrete containment.