• Korean Journal of Remote Sensing
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• v.34 no.6_3
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• pp.1457-1468
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• 2018

The sigma naught (${\sigma}^0$) equation is essential to calculate geo-physical properties from Synthetic Aperture Radar (SAR) images for the applications such as ground target identification,surface classification, sea wind speed calculation, and soil moisture estimation. In this paper, we are suggesting new Kompsat-5 (K5) Radar Cross Section (RCS) and ${\sigma}^0$ equations reflecting the final SAR processor update and absolute radiometric calibration in order to increase the application of K5 SAR images. Firstly, we analyzed the accuracy of the K5 RCS equation by using trihedral corner reflectors installed in the Kompsat calibration site in Mongolia. The average difference between the calculated values using RCS equation and the measured values with K5 SAR processor was about $0.2dBm^2$ for Spotlight and Stripmap imaging modes. In addition, the verification of the K5 ${\sigma}^0$ equation was carried out using the TerraSAR-X (TSX) and Sentinel-1A (S-1A) SAR images over Amazon rainforest, where the backscattering characteristics are not significantly affected by the seasonal change. The calculated ${\sigma}^0$ difference between K5 and TSX/S-1A was less than 0.6 dB. Considering the K5 absolute radiometric accuracy requirement, which is 2.0 dB ($1{\sigma}$), the average difference of $0.2dBm^2$ for RCS equation and the maximum difference of 0.6 dB for ${\sigma}^0$ equation show that the accuracies of the suggested equations are relatively high. In the future, the validity of the suggested RCS and ${\sigma}^0$ equations is expected to be verified through the application such as sea wind speed calculation, where quantitative analysis is possible.

• Journal of Radiation Protection and Research
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• v.39 no.1
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• pp.54-60
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• 2014

IAEA has employed various types of radiation detectors - HPGe, NaI, CZT - for accountancy of nuclear material. Among them, HPGe has been mainly used in verification activities required for high accuracy. Due to its essential cooling component(a liquid-nitrogen cooling or a mechanical cooling system), it is large and heavy and needs long cooling time before use. New hand-held portable HPGe has been developed to address such problems. This paper deals with results of performance evaluation test of the new hand-held portable HPGe prototype which was used during IAEA's inspection activities. Radioactive spectra obtained with the new portable HPGe showed different characteristics depending on types and enrichments of nuclear materials inspected. Also, Gamma-rays from daughter radioisotopes in the decay series of $^{235}U$ and $^{238}U$ and characteristic x-rays from uranium were able to be remarkably separated from other peaks in the spectra. A relative error of enrichment measured by the new portable HPGe was in the range of 9 to 27%. The enrichment measurement results didn't meet partially requirement of IAEA because of a small size of a radiation sensing material. This problem might be solved through a further study. This paper discusses how to determine enrichment of nuclear material as well as how to apply the new hand-held portable HPGe to safeguard inspection. There have been few papers to deal with IAEA inspection activity in Korea to verify accountancy of nuclear material in national nuclear facilities. This paper would contribute to analyzing results of safeguards inspection. Also, it is expected that things discussed about further improvement of a radiation detector would make contribution to development of a radiation detector in the related field.

• Journal of Korean Home Economics Education Association
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• v.17 no.2
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• pp.239-255
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• 2005

The purpose of this study was to understand middle school Home Economics teachers' family value and needs on learning objectives of family life area, and to identify the relationship between the two. Data was collected from the survey mailed to the teachers responsible for family life area in $\lceil$Technology/Home Economics$\rfloor$ in middle schools in Korea. The collected 312 questionnaires were used for final analysis. SPSS/WIN program was used for calculating average, standard deviation, percentage, t-test, ANOVA with post-verification scheffe., and correlation analysis. Followings are the summary of the results of this study. Firstly, the family value of middle school Home Economics teachers was relatively modern. They had very modem sense of value in all of the sub-areas such as sense of value on marriage. on gender role. on children, on filial love, and familism. Secondly, regarding needs on family life area of learning objects of Home Economics teachers, the requirement on emancipatory system of action was the highest. technical system of action was the next, and Communicative System of Action was the lowest. Thirdly, in the relationship between the needs of teaming objects of family life area and the family value, the needs of technical and interpretive behavioral system had few things to do with the family value. However. the needs on teaming object needs of emancipatory system of action was higher as the family value was modern. The trend in the relationship with needs was same in all the sub-areas such as sense of value on marriage, on gender role, on children. on filial love, and familism. However, the family value and the achievement level of family life area goals did not show significant correlation. Fourthly, regarding the family value and the needs on teaming objectives of family life area of middle school Home Economics teachers, those who were female, who had certificates for Home Economics Teaching, who were young and who had less experiences in teaching had more modem family value and required more teaming objectives in emancipatory system of action. Considering the results of the study, it is needed to emphasize the learning objects of emancipatory system of action in family life education by inducing consensus on the proposition that Home Economics subject is a critical and practical subject. To do this. it is needed to provide Home Economics teachers with emancipatory interest and mature family value through educating and refreshing them. It is desirable to separate Technology and Home Economics so that certificated Home Economics teachers could teach family life area. In that case they can teach the subject in the point of practical criticism. If the area is to be taught by other subject teachers there should be enough understanding on the philosophy and nature of Home Economics subject beforehand.