• 시스템엔지니어링워크숍
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• 통권1호
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• pp.60-64
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• 2003

In this study, we have analyzed the cost of korea high-speed railway system. The predicted cost in planning phase and adjustment data to 5th year are collected. Then, predicted cost is compared with adjustment in year/item/system base. We make a project history table for criteria to review project history and research & development activity. We have developed CBS(cost breakdown structure) and allocated adjustment data to them. It is shown that cost prediction related to research & development activity in planning phase is relatively correct.

• Child Health Nursing Research
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• 제24권4호
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• pp.443-453
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• 2018

Purpose: This study was describes the development and implementation a sex education program with a blended learning method for university students. Methods: Sixty-eight university students were recruited either to the experimental group (n=35) or the control group (n=33). This program was developed based on the analysis, design, development, implementation, and evaluation model. The analysis phase consisted of a literature review, focus group interview, expert consultations, and target group survey. In addition, learning objectives and structure were designed, and a printed text-book, presentation slides, cross-word puzzle, and debate topics were developed. In the implementation phase, the program was conducted 3 times over the course of 3 weeks. The evaluation phase involved verification of the effects of the program on sex-related knowledge, sexual autonomy, and justification of violence, as well as an assessment of satisfaction with the program. Results: The experimental group had significantly higher scores on sex-related knowledge (t=5.47, p<.001), sexual autonomy (t=2.40, p=.019), and justification of violence (t=2.52, p=.015) than the control group. Conclusion: The results indicate that this sex education program with blended learning was effective in meeting the needs of university students and can be widely used in this context.

• 한국건축시공학회지
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• 제23권3호
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• pp.327-336
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• 2023

The focus of this research was to devise a conceptual methodology for drone usage and to assess the viability of safety checklist items specific to drone application in safety oversight. The appraisal was grounded in a focus group interview involving professionals from construction management and safety fields. The proposed process was segmented into four stages: 1) pre-flight phase for flight plan development, 2) drone flight phase for safety condition inspection utilizing checklist items, 3) post-flight phase for visual asset analysis, and 4) documentation and management phase. Furthermore, the research scrutinized the applicability of 32 distinct safety checklist items for drone operations. The primary aim of this investigation was to probe the possible deployment of drones as part of construction safety inspections at work sites. However, it bears mentioning that subsequent research should strive to gather a more extensive sample size through questionnaire surveys, thereby facilitating quantitative analysis. Administering such surveys would yield more comprehensive data compared to a focus group interview, which was constrained by a limited participant count. In summation, this study lays a foundational groundwork for understanding the potential advantages and challenges associated with integrating drones into construction safety management.

• 한국군사과학기술학회지
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• 제27권2호
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• pp.285-293
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• 2024

This paper describes the interception using fine fragments and particles to hypersonic vehicles which have a vulnerability in thermal and pressure during glide-phase flight. This interception concept is based on the fast relative velocity and the flight vulnerability of hypersonic vehicles. For the density calculation of fragmentation and particle in interception, error analysis of end-phase was performed including radar, intercept missile and target maneuvering errors. In relation to the vulnerability and error analysis, the penetration characteristics of fine fragments in high temperature were analyzed. Presented the interception in glide-phase could be applied to the concept of horizontal multi-layer defense to hypersonic vehicles.

• 조명전기설비학회논문지
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• 제27권8호
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• pp.36-41
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• 2013

This paper is development of single-phase brushless DC motor with outer rotor for ventilation fan. Cogging torque causes the noise vibration to greatest impact on ventilation fan. Asymmetric notches are applied to tapered-teeth for cogging torque reduction of single-phase brushless DC motor. Initial model is notchless and proposed model is applied 2 asymmetric notches. The proposed method is proved motor characteristic through finite element analysis(FEA). Also, experimental results verify that the proposed model considerably reduces cogging torque and have the good sound quality in ventilation system.

• 동서간호학연구지
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• 제18권2호
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• pp.95-103
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• 2012

Purpose: This methodological study was done to develop a computerized telephone triage and consultation system for patients discharged with ophthalmic disease in order to provide more efficient practice guidelines for nurses, and evaluate the usability of the system. Methods: Development of the system consisted of six phases: strategic planning, analysis, design, implementation, evaluation, modification, and maintenance. Results: In the strategic planning phase, ophthalmic problems and nursing interventions of triage algorithms and practice guidelines were cross-mapped with the Omaha system. In the analysis phase, users requirements were identified. Then infrastructure including database, nursing knowledge base, and user interface were designed in the implementation phase. Usability and satisfaction of the system presented as very positive. Telephone consultation took about 2 minutes less than time in the previous system. The system was modified based on users' comments during the evaluation phase. Conclusion: This study was the first attempt in Korea to develop computerized triage system to prompt the quality of telephone consultation. It is suggestive that the computerized triage system may improve the quality of nursing.

• Journal of Power Electronics
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• 제13권5호
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• pp.884-895
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• 2013

In this paper, the Fourier-based PLL (Phase-locked Loop) is introduced with a new structure, capable of selective harmonic detection in single and three-phase systems. The application of the FB-PLL to harmonic detection is discussed and a new model applicable to three-phase systems is introduced. An analysis of the convergence of the FB-PLL based on a linear model is presented. Simulation and experimental results are included for performance analysis and to support the theoretical development. The decomposition of an input signal in its harmonic components using the Fourier theory is based on previous knowledge of the signal fundamental frequency, which cannot be easily implemented with input signals with varying frequencies or subjected to phase-angle jumps. In this scenario, the main contribution of this paper is the association of a phase-locked loop system, with a harmonic decomposition and reconstruction method, based on the well-established Fourier theory, to allow for the tracking of the fundamental component and desired harmonics from distorted input signals with a varying frequency, amplitude and phase-angle. The application of the proposed technique in three-phase systems is supported by results obtained under unbalanced and voltage sag conditions.

• 한국철도학회논문집
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• 제5권4호
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• pp.253-259
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• 2002

This paper presents the first simulation model using EMTDC program to analyze the electrified train voltage distribution characteristics in ac auto-transformer fed railroads. In general, all of the electrified train supply system has the characteristics that the train supply line is a naturally non-symmetrical and unbalanced system. Also, it is needed to model the Scott transformer which invert the balanced 3-phase quantity into 2-phase. Therefore, the general simulation methodology using previous simplified equivalent circuit or RMS based program can't obtain the accurate results to reflect the real-time operation because these methodology is basically assumed on completely 3-phase balanced system. To overcome these defects, in this paper, the EMTDC simulation model to analysis the completely electrified railroad system with Scott transformer and AC auto-transformer is presented. Also, the correctness of EMTDC modeling is confirmed by the old basic concepts and we think that this EMTDC model has the future powerful capability for application of railroad system analysis.

• 복식
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• 제55권4호
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• pp.1-15
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• 2005

For every country, the flag is a major symbol that represents the country. Establishing image though the use of the country's symbol is more important for achieving national competitiveness in this global age. In Korea, Taekuki has not been actively applied to fashion products, however Korean people began to realize the Taekuki as a motif of fashion with 2002 World Cup. Thus, research on fashion product development applying Taekuki is needed. This research developed designs for fashion product development applying Taekuki. In addition, through suggesting various applied motives, this research explored the product possibility of global fashion design that represents Korean identity and fashion. For research method, after research on fashion design process, design development was progressed according to the 4-phases that comprehends processes previous researchers presented. First, in the problem recognition phase, background on the introduction of Taekuki to products and Taekuki fashion during 2002 World Cup was analyzed. Then, the need and possibility of fashion product development applying Taekuki's formative characteristics were found. Second, in research and analysis phase, meaning and history of Taekuki as well as flag fashion product developments in the U.S. and England examples were reviewed. Also, individual interviews with experts and consumers were conducted to collect qualitative data regarding product and design direction. Third, in idealization for problem solving phase, 62 designs including 43 apparels and 19 accessories were emerged. Finally, in evaluation phase, 40 university students majoring design evaluated designs' creativity, function, uniqueness, symbol, aesthetics, and harmony. Through this research, it is expected that fashion products applying Taekuki will be formly established as a fashion item. Furthermore, it is also expected that product development in other categories, brand planning, and product development using other national symbols such as name, anthem, and flower will be followed.

• 한국세라믹학회지
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• 제48권5호
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• pp.471-478
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• 2011

Investigations of crystal structure and phase transition of $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics doped with A-site substitution impurity (La, Nd) or B-site substitution impurity (Sb, Nb) at 2 mol% concentration were carried out. X-ray diffraction patterns of impurities doped $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics have been measured at pressures up to ~5 GPa with diamond anvil cell and synchrotron radiation. The patterns were obtained at room temperature using methanol-ethanol mixture as pressure-transmitting media. In order to refine the crystal structure, Rietveld analysis has been performed. The structures of impurities doped $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics are tetragonal in space group P4mm at ambient pressure and are transformed into a cubic phase in space group Pm$\bar{3}$m as the pressure increases. In this study, when A-site substitution donor $La^{3+}$ or $Nd^{3+}$ ion was added to $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics, the phase transition phenomena showed up at the pressure of 2.5~4.6 GPa, but when B-site substitution donor $Nb^{5+}$ or $Sb^{5+}$ ion was added to it, the phase transition appeared at relatively lower pressure of 1.7~2.6 GPa.