• Nuclear Engineering and Technology
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• v.46 no.3
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• pp.373-380
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• 2014

Safety-related parameters are very important for confirming the status of a nuclear power plant. In particular, the reactor vessel water level has a direct impact on the safety fortress by confirming reactor core cooling. In this study, the reactor vessel water level under the condition of a severe accident, where the water level could not be measured, was predicted using a fuzzy neural network (FNN). The prediction model was developed using training data, and validated using independent test data. The data was generated from simulations of the optimized power reactor 1000 (OPR1000) using MAAP4 code. The informative data for training the FNN model was selected using the subtractive clustering method. The prediction performance of the reactor vessel water level was quite satisfactory, but a few large errors were occasionally observed. To check the effect of instrument errors, the prediction model was verified using data containing artificially added errors. The developed FNN model was sufficiently accurate to be used to predict the reactor vessel water level in severe accident situations where the integrity of the reactor vessel water level sensor is compromised. Furthermore, if the developed FNN model can be optimized using a variety of data, it should be possible to predict the reactor vessel water level precisely.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.23 no.1
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• pp.5-26
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• 2012

Mapping FRSAD and other ontology models intends to suggest a higher knowledge level that is independent of any information implementation system or specific context, and to endeavor to focus on the semantics, knowledge structures, subject access, and interoperability. Providing an application of FRSAD model to information environment and representing and sharing the information within the library sector and beyond, there needs encoding scheme for knowledge representation. This study suggested an OWL based ontology architecture for FRSAD model and demonstrated the pilot FRSAD ontology model using Prot$\acute{e}$g$\acute{e}$ software.

• The Journal of Korean Association of Computer Education
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• v.18 no.1
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• pp.45-54
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• 2015

A whole society has become software-driven and each independent fields has become convergence based on computing as the new digital economy era has come. This change affect computational literacy using computational thinking is emphasized the importance as the core competence for the future living. It means that supply of manpower with understanding software principle will decide the fate of the country. For this reason, each country are reinforcing computer science education or computing education. In this paper, we researched and analysed on new global trends of computer education in school especially focused on national curriculum and policy.

• Publications of The Korean Astronomical Society
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• v.19 no.1
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• pp.109-119
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• 2004

As a core project of the Korean Astronomical Data Center (KADC) in Korea Astronomy Observatory (KAO), we have constructed a framework of astronomical database using MySQL and JSP. MySQL database server is a powerful open source database management system, and JSP technology provides a simplified, fast way to create dynamic web content. Combined together, MySQL and JSP enable us to develop server-independent web-based applications efficiently in a short amount of time. The MySQL tables and JSP programs embedded in our database are built/written in a way to benefit both users and managers. We plan to expand our database by supplementing additional data in the near future. Our newly constructed database is expected to be the prototype of the Korean Virtual Observatory (KVO).

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.99-104
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• 2002

This study deals with the optimal design of a DC reactor type high-Tc superconducting fault current limiter(SFCL). The condition in which the cost function is minimized under given constraints is one of the things to be first considered in developing SFCLS. This condition is a group of the values corresponding to the variables the cost function depends on. In this paper, the length of tape was taken as a dependent variable, the inductance of DC reactor and the turns ratio of magnetic core reactors as independent variables. For the SFCL available at the level of 6.6kV-200A, we examined 4 cases; at the fault times of 80msec, 50msec, 30msec and 10msec. Since thyristors would be utilized instead of diodes, we chose the result at 10msec as the basic data. Considering safety factor 30%, our optimal design was decided to be the inductance 570mH, the critical current over 620A, the turns ratio 0.89 and the fault time within 20msec.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.286-288
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• 2007

In this paper, the fast locking PLL Frequency Synthesizer with low phase noise in a 0.18um CMOS process is presented. Its main application IS for the 915MHz ISM band wireless transponder upon the CPFSK (Continuous Phase Frequency Shift Keying) modulation scheme. Frequency synthesizer, which in this paper, is designed based on self-biased techniques and is independent with processing technology when damping factor and bandwidth fixed to most important parameters as operating frequency ratio, broad frequency range, and input phase offset cancellation. The proposed frequecy synthesizer, which is fully-integrated and is in 320M $^{\sim}$ 960MHz of the frequency range with 10MHz of frequency resolution. And its is implemented based on integer-N architecture. Its power consumption is 50mW at 1.8V of supply voltage and core area is $540{\mu}m$ ${\times}$ $450{\mu}m$. The measured phase noises are -117.92dBc/Hz at 10MHz offset, with low settling time less than $3.3{\mu}s$.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.127-132
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• 2009

This paper represents the analysis and design of the generic mission operations system for next generation satellite mission. In the past, mission operations systems were developed by their own mission requirements respectively. However, these systems have the similar architecture and common functions. Mission operations systems, in general, consist of mission independent module and mission specific module. In this paper, the generic framework for the mission scheduling and automation are introduced and analyzed. Using these generic frameworks, the risk and cost for operations system development can be reduced significantly. And, these frameworks might be used for the core technology in the development of mission operations system in the future.

• The Journal of the Korea Contents Association
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• v.7 no.12
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• pp.273-282
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• 2007

The Domain Name System (DNS) is the core system for managing Internet address resources, providing the most fundamental naming service. Currently, the DNS is classified into a tree structure. In this structure, it is difficult to normally access to the lower DNS, when there is an error in the upper DNS. Such a risk still remains even when a supplementary DNS is operated. However, due to the merit of the DNS enabling fast searches, it is impracticable to abandon the current tree structure. To efficiently correspond to DNS errors, this study suggests a method where the merit of the current tree structure is kept, while a temporary operation of the local DNS is available when errors occur by adding a horizontal and independent DNS structure.

• Journal of Korean Academy of Nursing Administration
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• v.15 no.3
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• pp.391-402
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• 2009

Purpose: The purpose of this research was to describe the decision making experience of VIP ward nurses in the clinical practice adjustment process. The research question was about "how nurses adjust their clinical practice to nursing situations and develop decision making process in a VIP ward." Method: The methodology of collecting and analyzing the data was based on the grounded theory of Strauss and Corbin(1998). The data was collected through in-depth interviews with 10 nurses from July to November, 2007. Results: The core category of nursing care decision making process was named as "adjusting with flexibility and deepened insight." The clinical practice adjustment process in nursing care decision making has progressed through four preceding interlocking phases: 1) dependent phase, 2) defensive phase, 3) independent phase, 4) integrative phase. These phases were classified by the level of nurses' dependency, proactivity, presupposition and integration. Conclusion: The result of this study indicated that nurse's decision making depended on their experiences and the nature of social context in which nursing occurs. Therefore, it is important to elaborate an effective training program for nurses to develop the phases of nursing care decision making.

• Journal of Engineering Education Research
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• v.15 no.6
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• pp.80-85
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• 2012

This study investigates significant factors regarding college freshman engineering students and analyses each factors influence on student satisfaction in the College of Engineering core curriculum. We carried out a survey targeting 505 students who completed their fundamental education for major course learning in the 2011 academic year while attending one college in Gwangju and ruled out inadequate respondents. A total sample size 437 students were analyzed. The seven independent variables are academic fees, academic term period, academic environment of the classroom, learning material content, time of lecture, student sincerity and student need for the program. The dependent variable is fundamental education satisfaction level. As a result of multiple regression analysis, the following factors were found to be significant in the following order: learning material content, time of lecture, student sincerity, student need for the program, academic fees and academic environment of the classroom. On the other side academic term period was not significant. For improving fundamental education satisfaction, there is a need for prudent consideration regarding learning material development and lecture times. Also further investigation should take place for policies necessary for increasing learner motivation and sincerity, and expand appropriate conditions for learners to become self-aware of the education they need within their major.