• The Korean Journal of Nuclear Medicine
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• v.32 no.6
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• pp.525-533
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• 1998

Purpose: Radiation adaptive response in human peripheral lymphocytes and mouse bone marrow cells was investigated using both metaphase analysis and micronucleus assay. We assessed the correlation between both tests. Materials and Methods: Two groups of the human peripheral lymphocytes and mouse bone marrow cells were exposed to low dose (conditioning dose, 0,18 Gy) or high dose (challenging dose, 2 Gy) ${\gamma}$-rays. The other 4 groups were exposed to low dose followed by high dose after several time intervals (4, 7, 12, and 24 hours, respectively). The frequencies of chromosomal aberrations in metaphase analysis and micronuclei in micronucleus assay were counted. Results: Chromosomal aberrations and micronuclei of preexposed group were lower than those of the group only exposed to high dose radiation. Maximal reduction in frequencies of chromosomal aberrations were observed in the group to which challenging dose was given at 7 hour after a conditioning dose (p<0.001). Metaphase analysis and micronucleus assay revealed very good correlation in both human lymphocytes and mouse bone marrow cells (r=0.98, p<0.001 ; r=0.99, p=0.001, respectively). Conclusion: Radiation adaptive response could be induced by low dose irradiation in both human lymphocytes and mouse bone marrow cells. There was a significant correlation between metaphase analysis and micronucleus assay.

• Proceedings of the Korea Contents Association Conference
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• 2019.05a
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• pp.471-472
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• 2019

많은 나양한 교수법들이 존재하지만 일반적으로 공학 교과목에서는 PBL교수법과 프로젝트 팀 교수법을 가장 많이 사용하고 있다. 본 논문에서는 2018년 2학기 공학 프로그래밍 교과목을 3개를 선정하여 PBL 교수법과 프로젝트팀 교수법을 적용하였고, 두 교수법의 학습만족도, 교육성장도, 학업성취도를 설문조사하여 학습효과를 분석하여 보았다. 그 결과는 저학년은 PBL법이, 고학년은 프로젝트 팀 교수법이 학습효과가 좋았다. 따라서 같은 프로그래밍 교육이지만 학년에 따라 교수법을 달리 선택할 필요가 있다.

• Korean Journal of Cognitive Science
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• v.11 no.1
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• pp.33-45
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• 2000

The present study examined the usability of the web site design, focusing on the cognitive characteristics of the WWW. Specifically, we conducted two major non-experimental usability testing methods on the domestic web sites with various purposes. In research I. we used an on-line questionnaire method on 12 domestic web sites. As a result. several critical usability features and factors were identified. In research 2. we carried out a heuristic evaluation method to identify more specific usability problems The result of research 2 suggests that the heuristic evaluation method reveals more specific problems of the web site design than the questionnaire method.

• Geophysics and Geophysical Exploration
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• v.11 no.2
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• pp.109-115
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• 2008

It is very important to estimate the physical properties of survey area and delineate the geological basement in marine site survey for the design of offshore structures. For the purpose of providing high quality data by means of engineering site survey, it is necessary to apply several survey techniques and carry out the integrated interpretation to each other. In this study, we applied single channel seismic reflection method and OBC (Ocean Bottom Cable) type seismic refraction method at shallow marine. We used a dual boomer-single channel streamer as a source-receiver in seismic reflection survey and airgun source-the developed OBC type streamer in seismic refraction survey. We made 24 channels OBC type streamer which has 4m channel interval and each channel is composed of single hydrophone and preamplifier. We tested the field applicability of the proposed method and applied the typical seismic data processing methods to the obtained reflection data in order to enhance the data quality and image resolution. In order to estimate the geological velocity distribution from refraction data, seismic refraction tomography technique was applied. Therefore, we could successfully perform time-depth conversion using the velocity information as an integrated interpretation. The proposed method could provide reliable geologic information such as sediment layer thickness and 3D basement depth map.

• Korea journal of population studies
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• v.19 no.1
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• pp.73-92
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• 1996

There are basically three approaches of surveys on the economically active population, namely Labor Force Approach (or Current Status Approach), Usual Status Approach, and Gainful Worker Approach. The selection of an approach among these approaches to be applied to a survey or population census should take into considerations the purpose and background of the survey or the census and the socio-economic situation of a country. In the Korean Population and Housing Census series which have been taken almost every five years since its first round in 1925, a sample survey on the economically active population has been adopted since the 1960 round of census. Even if the labor force approach continued to be applied to the censns prior to 1980, the approach has been different from one round to another in recent rounds. It may be suggested that the labor force approach continue to be adopted for the Korean Population and Housing Census for the following reasons: 1) the proportion of seasonal workers to the total workers is very small, 2) the proportion of population whose type of activity for a specific duration is different from that for one year is small, 3) the approach for the census should be the same as that for a variety of sample surveys on the economically active population which adopt the labor force approach, since the census functions as a population as well as a bench mark for those sample surveys, 4) an application of labor force approach will facilitate international comparisons since most of countries that conduct a population census adopt this approach, 5) the labor force approach can improve the reliability of results, thanks to its short reference period, etc.

• Tunnel and Underground Space
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• v.25 no.2
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• pp.210-219
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• 2015

This paper describes a new quantitative process for evaluating the roughness of discontinuity, which is suggested as a qualitative criteria in RMR or Q-system. For this purpose, the Delphi method which is one of the surveying methods was introduced. The selected panels were asked to evaluate the roughness of discontinuities on the Web which was hosted by authors in advance. A total of 3 surveys were performed using JRCs suggested by Barton and Choubey as well as Ai generated by the Monte Carlo simulations. After each survey, the results were provided to all panels for comparing their decisions to others. As surveys proceeded, better consensus and convergence were achieved. With a good agreement of panels on roughness classification, the quantitative criteria for roughness of discontinuity in RMR and Q-system was established in this study.

• Journal of Food Hygiene and Safety
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• v.17 no.3
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• pp.166-172
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• 2002

This study has been carried out to estimate the average daily intakes of preservatives commonly used in Korea. The survey method, which is specific approach that can be applicable for Koreans has been proposed to estimate the daily intakes. The ADIS of sorbates, benzoates, and esters of p-hydroxybenzoic acid were less than 1% and judged to be safe. The EDIs of sorbates, benzoates, and esters of p-hydroxybenzoic acid were 0.39, 0.29, and 0.04 mg/kg bw/day respectively. And these data were compared with existing data. In case with sorbates, the EDI of survey data was higher than that of analytical data but much lower than that of maximum permitted level data. Also, the EDIs of benzoates and esters of p-hydroxybenzoic acid showed to be the same results. In conclusion, the EDIs of survey data lie between maximum Permitted level data and analytical data of Preservatives. The survey method could be considered as the possible alternative of refined method.

• Proceedings of the Korean Association for Survey Research Conference
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• 2003.06a
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• pp.29-33
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• 2003

In business survey. cut off sampling is usual. The contribution from cut off part of the population is at least small in comparison with the remaining population. In this study. the population have been separated as three stratum, cut-off. take-some, take-all, and we will estimate cut-off part.

• Proceedings of the Korean Statistical Society Conference
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• 2002.11a
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• pp.35-42
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• 2002

본 연구에서는 2000년 어업총조사에서 얻은 어가를 모집단으로 하여 어가경세조사를 위한 표본설계룰 하였다. 진체 어가를 전업 및 1종 겸업어가를 포함하는 부차모집단1과 2종 겸업어가로 구성된 부차모집단2로 구분하였다. 새로운 표본설계에서는 최적 집락크기를 구하고, 층화를 위해서 SAS Enterprise Miner에서 제공하고 있는 의사결정나무모형(Decision Tree Model)을 이용하였다. 층별 표본배정은 네이만 배정법을 사용하였고 두 가지 추정법을 제시하였다.

• Journal of Korean Society of Forest Science
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• v.46 no.1
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• pp.29-43
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• 1980

The sampling methods selected for this area was (1) Simple random sampling (2) Systematic sampling and (3) Sub-sampling. For the calculation of the number of sampling plot, 10 % coefficient of variation was adapted. As a result, 57 plots each for simple random sampling and systematic sampling was calculated. In the sub-sampling method, however, total of 40 plots, which were consisted of 5 Blocks, secondary 4 major units and tertiary 2 minor units, were examined. The reuslts obtained are summarized as follows : 1. The rate of expected error was 9.24% for simple random sampling, 8.36% for systematic sampling and 7.54% for sub-sampling, respectively. Therefore, the sub-sampling was proved to be the most accurate method among the test. 2. The volume calculated by each sampling method was compared to the volume of all stand. The rate of expected error was also lowest in the sub-sampling (0.39%), followed by systematic sampling (4.18%) and simple random sampling (7.92%). 3. Comparing the various reuslts and analysis of these results, the sub-sampling was regarded as the most rapid and economical method because this method had not only the least number of plots but also the least expected error among the tested sampling methods Therefore the sub-sampling is proved to be an ideal sampling method for forest survey.