• Journal of the Korean BIBLIA Society for library and Information Science
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• 제27권1호
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• pp.59-85
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• 2016

The purpose of this study was to synthesize the effects of the information literacy instruction using meta-analysis. Results using random-effect models were as follows. First, the overall average effect size (ES) of information literacy instruction (Hedges'g) was 0.72, which could be interpreted based on Cohen's guidelines as moderate to large. Second, the two types of information literacy instruction, demonstrating more than medium ESs, did not show significant differences in their ESs. Third, the ESs of information literacy instruction differed depending on the measuring variables. Fourth, grade, study design and the form of the measurement tool were moderator variables that explain the differences in ESs. In sum, the effects of information literacy instruction, having more than medium effect size, seem quite stable across instruction types and study designs.

• The Transactions of the Korean Institute of Power Electronics
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• 제14권6호
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• pp.496-503
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• 2009

In this paper, a new three-phase interleaved isolated high efficiency boost dc-dc converter with active clamp is proposed. The converter is capable of increased power transfer due to its three-phase power configuration, and it reduces the rms current per phase, thus reducing conduction losses. Further, interleaved operation of three-phase boost converter reduces overall ripple current, which is imposed into fuel cells and realizes smaller sized filter components, increasing effective operating frequency and leading to higher power density. Each output current of three-phase boost converter is combined by the three-phase transformer and flows in the continuous conduction mode by the proposed three-phase PWM strategy. An efficiency of above 96% is mainly achieved by reducing conduction losses and switching losses are reduced by the action of active clamp branches, as well. The proposed converter and three-phase PWM strategy are analyzed, simulated and implemented in hardware. Experimental results are obtained on a 500 W prototype unit, with all of the design verified and analyzed.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2007년도 학술대회 2부
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• pp.489-496
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• 2007

u-러닝(u-learning) 체제의 도입은, 다양한 형태의 원격교육을 지원하기 위한 교수-학습 시스템 및 모형을 요구하며, 이에 따라 유무선 인터넷을 이용한 u-러닝 시스템이 지속적으로 개발 적용되어 왔다. 하지만, 현재 운영되고 있는 대부분의 원격교육시스템은 교수자와 학습자간의 지속적인 쌍방향 상호작용 유지의 어려움, 시스템 구축을 위한 경제적 부담, 시스템 운영에 투입되는 교수자의 기술적 소양 부족 등의 문제점을 안고 있다. 이러한 문제점을 해결하기 위해서는 다음 항목에 대한 제고가 필요하다. 첫째, 효율적인 쌍방향 상호작용은 학습자 행동에 대한 지속적인 모니터링 및 피드백, 그리고 교수자의 상시 접속 상태 유지를 전제로 한다. 이는 사이버 교사(cyber tutor)를 이용하는 지능형 학습에 대한 논의로 이어진다. 둘째, 구현될 시스템은 경제성과 재사용성 측면이 고려되어야 하며, 이는 기존의 학교 현장의 인프라를 활용하는 u-러닝 개념의 학습 환경, 즉 이동성 네트워크 구조에 대한 설계가 요구된다. 셋째, 시스템의 직접적인 운영 주체인 일선 교사들의 기술적 소양을 고려할 때, 시스템 구축 및 사용상의 편리성, 학습 진행을 위한 보조적 지원 장치 등이 충분히 전제되어야 한다. 이에 본 연구에서는, 이동성과 내재성의 u-러닝 개념을 포함하고, 지능형 가상 교수자(cyber tutor)에 의한 블랜디드 학습(blended learning)을 도입하며, 사용자의 기술적, 경제적 부담의 제거가 가능한 지능형 u-러닝시스템을 개발하였다. 본 연구에 의해 개발된 시스템은 기존의 네트워크 인프라와 u-러닝의 개념을 통합하는 네트워크 구조, 원격학습을 지원하는 네트워크 화이트보드, 학습 과정의 저장과 해석을 지원하는 스크립트 인터프리터, 학습자 반응에 대한 피드백을 자동 제공할 수 있는 지능형 인터프리터로 구성되었다.

• Journal of the Korean Association of Geographic Information Studies
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• 제11권4호
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• pp.64-75
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• 2008

Since the current database systems for managing geotechnical investigation results were limited by being described boring test result in point feature, it has been trouble for using other GIS data. Although there are some studies for spatial characteristics of subsurface modeling, it is rather lack of being interoperable with GIS, considering geotechnical engineering facts. This is reason for difficulty of practical uses. In this study, we has developed subsurface spatial information model through extracting needed geotechnical engineering data from geotechnical information DB. The developed geotechnical information clustering program(GEOCL) has made a cluster of boring formation(and formation ratio), classification of layer, and strength characteristics of subsurface. The interpolation of boring data has been achieved through zonal kriging method in the consideration of spatial distribution of created cluster. Finally, we make a subsurface spatial information model to integrate with digital elevation model, and visualize 3-dimensional model by subsurface spatial information viewing program(SSIVIEW). We expect to strengthen application capacity of developed model in subsurface interpretation and foundation design of construction works.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.250-257
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• 2007

The development of aircraft engine requires a lot of time and cost to estimate system attributes such as performance, reliability, stability and life. A virtual engine test based on "Numerical test cell" can extremely reduce the time and cost for the development of a hardware by coupling multidisciplinary analyses. This paper presents the development activities of full engine simulation programs in U.S.A. and Europe. NASA Glenn research center of U.S.A. leads the development efforts of NPSS(Numerical Propulsion System Simulation) by assembling the existing codes and improving their functions. VIVACE (Value Improvement through a Virtual Aeronautical Collaborative Enterprise), a consortium of universities, research centers and companies in Europe is developing the PROOSIS(PRopulsion Object Oriented SImulation Software) by integrating the various programs of the institutes. The capability for the domestic development is also estimated by surveying the current status.

• Journal of the Korean Institute of Telematics and Electronics S
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• 제35S권10호
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• pp.94-117
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• 1998

This paper investigates the performance characteristics of the data link layer of the 1996 version of IEC/ISA fieldbus which is developed as internatioal standard of fieldbus. A discrete-event simulation model of the data link layer of IEC/ISA fieldbus is developed. Using the simulation model, this paper identifies the network parameters that influence the performance of prioritys scheme and real-time data transmission, and analyzes the delay performance of IEC/ISA fieldbus with respect to the change of network parameters. The simulation model also integrates continuous-time simulation model of a control system as application process. Using the integrated simulation model, this study investigates the effect of network-induced delay on the performance of control system. Since the simulation model developed in this study can predict the network performance, it will be effectively utilized in the design phase of control and automation systems that adopt the IEC/ISA fieldbus.

• Journal of the Korean Society of Propulsion Engineers
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• 제26권5호
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• pp.63-73
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• 2022

Investigation on operation of the test apparatus for the M4 semi-freejet tests with a full-scale vehicle model was carried out utilizing domestic facilities. An integrated design of the experimental apparatus and the vehicle model was obtained through iterative computational fluid dynamics (CFD) analysis. The test results showed that the M4 nozzle of the apparatus was fully expanded to provide required test conditions. It was also found that the intake of the vehicle model successfully started, and the corresponding shadowgraph images were recorded during the test. A variable nozzle of the model was set to adjust the back pressure of the model combustor, and wall-static pressures were measured to obtain the pressure distribution at the main locations of the model. The flame of torch ignitors and pilot fuel ignition were observed in a flame-holder of the combustor.

• Journal of the Korean Society for Library and Information Science
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• 제57권4호
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• pp.185-208
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• 2023

In this study, a research model was designed and verified in order to determine whether the communication styles of public library managers affect employees' empowerment, job satisfaction, and life satisfaction. A survey was conducted among employees of four public libraries in the Gyeonggi region and 24 libraries in Seoul, and 229 valid responses were analyzed. The analysis revealed that authoritative communication style influenced employees' job satisfaction, while social communication style influenced their empowerment. Additionally, employees' empowerment impacted their job satisfaction, which in turn affected their life satisfaction. This implies that job satisfaction and life satisfaction of the employees can be achieved after communication and empowerment were well established within the organization. This study is meaningful in suggesting an effective management direction for strengthening the essence and foundation of public libraries by examining the theoretical significance and implications of the research result. This study also suggested that in the future, another research should be conducted based on a variety of characteristics by integrating the different communication styles of researchers.

• Journal of the Korean Association of Geographic Information Studies
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• 제9권4호
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• pp.34-44
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• 2006

Simulation models allow researchers to model large hydrological catchment for comprehensive management of the water resources and explication of the diffuse pollution processes, such as land-use changes by development plan of the region. Recently, there have been reported many researches that examine water body quality using Geographic Information System (GIS) and dynamic watershed models such as AGNPS, HSPF, SWAT that necessitate handling large amounts of data. The aim of this study is to develop a watershed based water quality estimation system for the impact assessment on stream water quality. KBASIN-HSPF, proposed in this study, provides easy data compiling for HSPF by facilitating the setup and simulation process. It also assists the spatial interpretation of point and non-point pollutant information and thiessen rainfall creation and pre and post processing for large environmental data An integration methodology of GIS and water quality model for the preprocessing geo-morphologic data was designed by coupling the data model KBASIN-HSPF interface comprises four modules: registration and modification of basic environmental information, watershed delineation generator, watershed geo-morphologic index calculator and model input file processor. KBASIN-HSPF was applied to simulate the water quality impact by variation of subbasin pollution discharge structure.

• Spatial Information Research
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• 제9권2호
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• pp.239-261
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• 2001

A large suite of official statistical data sets has been compiled for geographical units under the national directives, and it is the quantitative regional analysis procedures that could add values to them. This paper reports our attempts at prototyping a statistical GIS which is capable of serving over the Web a variety of regional analysis routines as well as value-added statistics and maps. A pilot database of some major statistical data was ingested for the city of Seoul. The baseline subset of regional analysis methods of practical usage was selected and accommodated into the business logic of the target system, which ranges from descriptive statistics, regional structure/inequality measures, spatial ANOVA, spatial (auto) correlation to regression and residual analysis. The leading-edge information technologies including the application server were adopted in the system design and implementation so that the database, analysis modules and analytic mapping components may cooperate seamlessly behind the Web front-end. The prototyped system supports tables, maps, and files of downloadable format for input and output of the analyses. One of the most salient features of out proposed system is that both the database and analysis modules are extensible via the bi-directional interface for end users; The system provides users with operators and parsers for algebraic formulae such that the stored statistical variables may be transformed and combined into the newly-derived set of variables. This functionality eventually leads to on-the-fly fabrication of user-defined regional analysis algorithms. The stored dataset may also be temporarily augmented by user-uploaded dataset; The extension of this form, in essence, results in a virtual database which awaits for users commands as usual. An initial evaluation of the proposed system confirms that the issues involving the usage and dissemination of information can be addressed with success.