• Journal of Digital Convergence
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• v.10 no.10
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• pp.439-445
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• 2012

The aim of the work that is presented in this paper is to develop the new prior educational materials which use the field trip and to present educational possibilities. The QR codes were used to develop the prior materials. The developed materials applied to elementary students who attended to filed trips in 2012. This was practically achieved by the use of smartphone which enhance the learning experience of a physical visit by providing personalized information with QR codes. The results demonstrate the technology supported physical field trips provides significantly improved learning outcomes, increases students curiosity. Furthermore the findings of the study demonstrate that the application of the specific emerging technologies could facilitate the development of advanced learning experiences in field trips, increasing at a significant level the learning outcomes and the motivation of the participating students.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.9
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• pp.907-915
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• 2008

The computational fluid dynamic analysis has been conducted for the thermo-chemical flow field in an arcjet thruster with mono-propellant Hydrazine (N2H4) as a working fluid. The Reynolds Averaged Navier-Stokes (RANS) equations are modified to analyze compressible flows with the thermal radiation and electric field. the Maxwell equation, which is loosely coupled with the fluid dynamic equations through the Ohm heating and Lorentz forces, is adopted to analyze the electric field induced by the electric arc. The chemical reactions of Hydrazine were assumed to be infinitely fast due to the high temperature field inside the arcjet thruster. The chemical and the thermal radiation models for the nitrogen-hydrogen mixture and optical thick media respectively, were incorporated with the fluid dynamic equations. The results show that performance indices of the arcjet thruster with 1kW arc heating are improved by amount of 180% in thrust and 200% in specific impulse more than frozen flow. In addition thermo-physical process inside the arcjet thruster is understood from the flow field results.

• Radiation Oncology Journal
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• v.35 no.2
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• pp.144-152
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• 2017

Purpose: The role of radiotherapy (RT) was largely deserted after the introduction of platinum-based chemotherapy, but still survival rates are disappointingly low. This study focuses on assessing the clinical efficacy of RT in relation to chemotherapy resistance. Materials and Methods: From October 2002 to January 2015, 44 patients were diagnosed with epithelial ovarian cancer (EOC) and treated with palliative RT for persistent or recurrent EOC. All patients received initial treatment with optimal debulking surgery and adjuvant platinum-based chemotherapy. The biologically effective dose (BED) was calculated with ${\alpha}/{\beta}$ set at 10. Ninety-four sites were treated with RT with a median BED of 50.7 Gy (range 28.0 to 79.2 Gy). The primary end-point was the in-field local control (LC) interval, defined as the time interval from the date RT was completed to the date any progressive or newly recurring disease within the RT field was detected on radiographic imaging. Results: The median follow-up duration was 52.3 months (range 7.7 to 179.0 months). The 1-year and 2-year in-field LC rates were 66.0% and 55.0%, respectively. Comparisons of percent change of in-field tumor response showed similar distribution of responses among chemoresistant and chemosensitive tumors. On multivariate analysis of predictive factors for in-field LC analyzed by sites treated, $BED{\geq}50Gy$ (hazard ratio, 0.4; confidence interval, 0.2-0.9; p = 0.025) showed better outcomes. Conclusion: Regardless of resistance to platinum-based chemotherapy, RT can be a feasible treatment modality for patients with persistent of recurrent EOC. The specific role of RT using updated approaches needs to be reassessed.

• Journal of The Korean Association of Information Education
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• v.21 no.2
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• pp.231-245
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• 2017

This study is to review current state of web-based simulations for science learning about magnets and magnetic field, and evaluate the appropriateness of simulations in terms of contents, strategies and design. We designed a set of criteria for evaluating science simulations and applied it to 14 simulations about magnets and magnetic field. For the evaluation, eight elementary teachers participated and they described specific characteristics of each simulation according to the criteria. Based on the evaluation, we divided the simulations into two groups, excellent vs. normal groups. We analyzed strengths from the simulations in excellent group and weaknesses from the simulations in normal group according to the contents, learning strategies, screen format, and technical features. Implications for ways of improvement in developing web-based science simulations effective to science teaching and learning about magnets and magnetic field were discussed.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.49.2-49.2
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• 2017

Star forming dwarf galaxies in various environments are attractive objects for investigating the environmental effects on chemical evolution of dwarf galaxies. Using SDSS DR7 spectroscopic data and GALEX ultraviolet (UV) imaging data, we study the chemical properties of star forming dwarf galaxies in various environments of the Virgo cluster, Ursa Major group, and field. We derived gas-phase abundance, galaxy mass, and UV specific star formation rate (sSFR) of subsample, early-type (ETD) and late-type star forming dwarf (LTD) galaxies, which are divided by visually classified galaxy morphology. We found no O/H enhancement of LTDs in cluster and group environments compared to the field, implying no environmental dependence of the mass-metallicity relation for LTDs. LTDs in the Virgo cluster and Ursa Major group have similar sSFR at a given galaxy mass, but they exhibit systematically lower sSFR than those in isolated field environment. We suggest that LTDs in the Virgo cluster are an infalling population that was recently accreted from the outside of the cluster. We found that ETDs in the Virgo cluster and Ursa Major group exhibit enhanced O/H compared to those in the field. However, no distinct difference of N/O of galaxies between different environments. The chemically evolved ETDs in the Virgo cluster and Ursa Major group also show similar mass-sSFR relation, but systematically lower sSFR at a fixed galaxy mass compared to the field counterparts. We suggest that ETDs in the Virgo cluster and Ursa Major group have evolved under the similar local environments. We also discuss the evolutionary path of ETDs and LTDs with respect to the environmental effects of ram pressure stripping and galaxy interaction/merging.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.489-494
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• 2008

The measurement of magnetic field is performed about DC and AC magnetic field in electric railway line. The test point is cap, on the converter/inverter box, on the traction motor and on the SIV, the height of measurement is bottom and 60 cm height. In case of AC magnetic field, the selected specific frequency is measured on the converter/inverter box. The AC magnetic field is checked and analysis through BNC output, DAQ cad and notebook PC.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.6
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• pp.255-261
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• 2005

Recently, the RF inductive discharge or inductively coupled plasma continues to attract growing attention as an effective plasma source in many industrial applications, the best known of which are plasma processing and lighting technology. To the point of lighting sources, the ring-shaped electrodeless fluorescent lamps utilizing an inductively coupled plasma have been objects of interest and research during the last decades, mainly because of their potential for extremely long life, high lamp efficacies, rapid power switching response. In this paper, maxwell 3D finite element analysis program (Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by 3D simulation software operated at 250 kHz and some specific conditions. The electromagnetic field in the ferrite core was shown to be high and symmetric. An LS-100 luminance meter and a Darsa-2000 spectrum analyzer were used in the experiment. According to data on the lamp tested using high magnetic field ferrite, the optical and thermal wave fields were shown to be high around the ring-shaped electrodeless fluorescent lamp. The optical or light field was high at the center of the bulb rather than around the ferrite core. The light conditions of the bulb were assumed to be complex, depending on the condition of the filler gas, the volume of the bulb, and the frequency of the inverter. Our results have shown coupling between the gas plasma and the field of the light emitted to be nonlinear.

• The Journal of Korean Academic Society of Nursing Education
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• v.20 no.4
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• pp.491-501
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• 2014

Purpose: Nursing is regarded as a female-dominated profession. However, the number of Korean males entering the field of nursing is increasing. This study examines which of the following factors influence professionalism in male and female student nurses: area of nursing, gender identity, gender stereotypes, satisfaction with the field, emotional intelligence, and interpersonal relationships. Method: In total, 133 male and 293 female student nurses were selected from four Korean provinces between July 2013 and February 2014 to participate in this study. The data were analyzed with descriptive statistics, t-tests, ${\chi}^2$-tests of independence, and multiple regression analyses using SPSS/Win 20 software. Results: In males, 47.4% of variance in nursing professionalism was accounted for by grades, interpersonal relationships, gender stereotypes, and satisfaction with the field. In females, 41.9% of variance in nursing professionalism was accounted for by satisfaction with the field, interpersonal relationships, area of nursing, age, emotional intelligence and grades. Common factors that influenced both genders included satisfaction with the field, interpersonal relationships and grades. Conclusion: Although males and females revealed no significant differences in overall mean scores of nursing professionalism, several factors influencing nursing professionalism did differ by gender. Therefore, gender-specific nursing educational and training programs may be necessary to promote professionalism among student nurses.

• Korean Journal of Construction Engineering and Management
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• v.11 no.1
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• pp.48-58
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• 2010

Recently, the application of construction management system is being increased and various research activities by each specific field are going on many universities and research institutes. It is necessary to understand the latest research trends by each subject for keeping up excellent products in CM field. This study suggests a subject breakdown structure for classifying detailed technologies of CM field. And over 2,000 domestic and international papers in the last five years are analyzed for analogizing research trends by each subject. The analyzed results include research trends by year and strong and weak fields by each research subject of CM technology. Finally, this study suggests an improved countermeasure for guaranteeing sustainable research activation in CM field.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.1032-1036
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• 2019

When the equipment which is related to safety or important to power production is installed in nuclear power plant units (NPPs), verification of equipment Electromagnetic Susceptibility (EMS) must be performed. The low-frequency radiated magnetic field susceptibility (RS101) test is one of the EMS tests specified in U.S NRC (Nuclear Regulatory Commission) Regulatory Guide (RG) 1.180 revision 1. The RS101 test verifies the ability of equipment installed in close proximity to sources of large radiated magnetic fields to withstand them. However, RG 1.180 revision 1 allows for an exemption of the low-frequency radiated magnetic susceptibility (RS101) test if the safety-related equipment will not be installed in areas with strong sources of magnetic fields. There is no specific exemption criterion in RG 1.180 revision 1. EPRI TR-102323 revision 4 specifically provides a guide that the low-frequency radiated magnetic field susceptibility (RS101) test can be conservatively exempted for equipment installed at least 1 m away from the sources of large magnetic fields (>300 A/m). But there is no exemption criterion for equipment installed within 1 m of the sources of smaller magnetic fields (<300 A/m). Since some types of equipment radiating magnetic flux are often installed near safety related equipment in an electrical equipment room (EER) and main control room (MCR), the RS101 test exemption criterion needs to be reasonably defined for the cases of installation within 1 m. There is also insufficient data regarding the strength of magnetic fields that can be used in NPPs. In order to ensure confidence in the RS101 test exemption criterion, we measured the strength of low-frequency radiated magnetic fields by distance. This study is expected to provide an insight into the RS101 test exemption criterion that meets the RG 1.180 revision 1. It also provides a margin analysis that can be used to mitigate the influence of low-frequency radiated magnetic field sources in NPPs.