• Proceedings of the KSRS Conference
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• v.2
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• pp.582-585
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• 2006

Augustine volcano is an active stratovolcano located southwest of Anchorage, Alaska. Augustine volcano experienced seven significantly explosive eruptions in 1812, 1883, 1908, 1935, 1963, 1976, and 1986, and a minor eruption in January 2006. To measure ground surface deformation of Augustine volcano, we applied satellite radar interferometry with ERS-1/2 and ENVISAT SAR images acquired from three descending and three ascending satellite tracks. Multiple interferograms are stacked to reduce artifacts due to changes in atmospheric condition and retrieve temporal deformation sequence. For this, we used Least Square (LS) method for reducing atmospheric effects and Singular Value Decomposition (SVD) method for the retrieval of a temporal deformation sequence. Interferograms before 2006 eruption show about 3 cm/year subsidence by contraction of pyroclastic flow deposits from the 1986 eruption. Interferograms during 2006 eruption do not show significant deformation around volcano crater. Interferograms after 2006 eruption show again a several cm subsidence by compaction and contraction of pyroclastic flow deposits for a few months. This study demonstrates that satellite radar interferometry can monitor deformation of Augustine volcano to help understand the magma plumbing system driving surface deformation.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.73-78
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• 2008

We introduce OBS and sonobuoy systems which are the typical wide-angle reflection/refraction seismic recorders made by KORDI for the investigation of crustal structure and the sediment/basement structure in the coastal area. These recording devices are examined for their usage through the test survey. The normal operation of these devices were proved and good recordings were obatined. The head waves are recognized in the sonobuoy records, which shows the possibility of velocity structure survey by the refraction and/or tomography method.

• Journal of The Korean Association For Science Education
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• v.30 no.5
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• pp.594-608
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• 2010

This research attempts to extract the factors that generate scientific interest, and verify the effect of extracted factors on the generation of scientific interest in middle school students' observation activity on life phenomenon. In order to analyze interest-generating factors, observation programs were applied four times in the science class of 3rd grade middle school students. And an interview was conducted towards students who had strong scientific interest among students who participated in the observation activity. After classifying the interview results according to the types, and 21 interest-generating factors were extracted. Interest-generating factors were classified into 5 categories; the characteristics of the observation object, the characteristics of the observation activity, the characteristics of the observation result, the characteristics of the observer, and the characteristics of the extrinsic factor. It was verified that interest-generating factors have an effect on the generation of scientific interest in the observation activity. First of all, in order to confirm whether the extracted generation factors would have an effect on the generation of interest in observation activity, as survey of interest-generating factors was drawn up. The observation activity program of 4 times' volume was applied towards third grade middle school students, and survey paper on interest-generating factor was input. Analysis result showed that factors have effect on the generation of interest. That is, it was confirmed that extracted interest-generating factor has a significant effect on the generation of scientific interest. The cause analysis on the uninteresting observation activity was possible, and it would play an essential role in developing an interesting observation activity.

• The Korean Journal of Applied Statistics
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• v.24 no.2
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• pp.393-400
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• 2011

In a large scale survey, cluster sampling design in which a set of observation units called clusters are selected is often used to satisfy practical restrictions on time and cost. Especially, a two stage cluster sampling design is preferred when a strong intra-class correlation exists among observation units. The sample Primary Sampling Unit(PSU) and Secondary Sampling Unit(SSU) size for a two stage cluster sample is determined by the survey cost and precision of the estimator calculated. For this study, we derive the optimal sample PSU and SSU size when the population SSU size across the PSU are di erent by extending the result obtained under the assumption that all PSU have the same number of SSU. The results on the sample size are then applied to the $4^{th}$ Korea Hospital Discharge results and is compared to the conventional method. We also propose the optimal sample SSU (discharged patients) size for the $7^{th}$ Korea Hospital Discharge Survey.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.594-604
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• 2017

The Korean National Institute of Fisheries Science (NIFS) has biannually (spring and fall, respectively) deployed a bottom trawl survey along the coastal areas for last decade, taking samples on a regular basis (i.e., a systematic sampling). Despite the availability of the survey data, NIFS has not yet officially reported the estimates of the groundfish population sizes as well as has not evaluated uncertainty of the estimates. The objectives of our study were to infer the relative size of a fish population, applying two different sampling techniques (namely simple and stratified sampling) with different observation units to the NIFS survey data, and to compare those two techniques in bias and precision. For demonstration purposes, we used data on Pacific cod (Gadus macrocephalus) collected by the 2011-2015 surveys, and the results of simple and stratified sampling showed that the point estimates and precision varied by observation unit as well as the sampling technique.

• Journal of Digital Convergence
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• v.13 no.12
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• pp.217-224
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• 2015

OBJECTIVES Handwashing rate of Korean people was lower than the rates of people in developed countries. The purpose of this study was to investigate handwashing rate, the factors influence people's handwashing behaviors during use of public restroom. METHODS This study used the data of '2013 Korea National Handwashing Survey'. The survey was done through direct observation on the user of subway and train station restroom from September 10 to 12, 2013. RESULTS Factors influencing handwashing with soap were administrative region(OR 0.490-2.255), purpose of toilet use(urination 1.000, defecation 2.505), drying method after handwashing(OR 0.497-3.107). CONCLUSIONS The results of this study will provide the evidence data of national handwashing promotion activities for preventing and controlling communicable diseases.

• Journal of Environmental Health Sciences
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• v.35 no.1
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• pp.36-44
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• 2009

Hand-washing has been recognized as a critical factor in controlling infection and cross-contamination. This study was performed to investigate hygienic behavior of male university students focusing on awareness of hand-washing, their hand washing practices, and the difference between their awareness and practices. Both a self-administered questionnaire survey and a separate direct observation in restrooms were carried out at a university campus over a four week period. In the survey, 93.6% of the responded students claimed to wash their hands after using toilet. However, just 16.9% of the observed students actually did so, according to a separate and unnoticed observational study. Among the observed students who washed their hands, 25.0% of them used soap, only 5.0% of them washed four parts of their hands, and 15.0% of them washed their hands for more than 10 seconds. Paper towel was the most common hand drying method in the direct observation and also in the survey. Significant differences between the questionnaire survey and the direct observation (p<0.0l) were found in hand-washing practices, duration of hand-washing, using soap, washing parts of the hand, and hand-drying method after using the toilet. This study indicates that there is a remarkable difference between the male university students' awareness of hand-washing and their hand-washing practices. This study reveals that there is the need for programs or campaigns to increase hand-washing practices of male university students.

• Korean Journal of Remote Sensing
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• v.39 no.2
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• pp.233-246
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• 2023

In terms of understanding the water cycle and efficient water resource management, the importance of soil moisture has been highlighted. However, in Korea, the lack of qualified in-situ soil moisture data results in very limited utility. Even if satellite-based data are applied, the absence of ground reference data makes objective evaluation and correction difficult. The cosmic-ray neutron probe (CRNP) can play a key role in producing data for satellite data calibration. The installation of CRNP is non-invasive, minimizing damage to the soil and vegetation environment, and has the advantage of having a spatial representative for the intermediate scale. These characteristics are advantageous to establish an observation network in Korea which has lots of mountainous areas with dense vegetation. Therefore, this study was conducted to evaluate the applicability of the CRNP soil moisture observatory in Korea as part of the establishment of a Korean cOsmic-ray Soil Moisture Observing System (KOSMOS). The CRNP observation station was installed with the Gunup-ri observation station, considering the ease of securing power and installation sites and the efficient use of other hydro-meteorological factors. In order to evaluate the CRNP soil moisture data, 12 additional in-situ soil moisture sensors were installed, and spatial representativeness was evaluated through a temporal stability analysis. The neutrons generated by CRNP were found to be about 1,087 counts per hour on average, which was lower than that of the Solmacheon observation station, indicating that the Hongcheon observation station has a more humid environment. Soil moisture was estimated through neutron correction and early-stage calibration of the observed neutron data. The CRNP soil moisture data showed a high correlation with r=0.82 and high accuracy with root mean square error=0.02 m³/m³ in validation with in-situ data, even in a short calibration period. It is expected that higher quality soil moisture data production with greater accuracy will be possible after recalibration with the accumulation of annual data reflecting seasonal patterns. These results, together with previous studies that verified the excellence of CRNP soil moisture data, suggest that high-quality soil moisture data can be produced when constructing KOSMOS.

• Journal of The Korean Association For Science Education
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• v.43 no.2
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• pp.111-124
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• 2023

The aim of this study was to explore science teachers' perceptions of good science teaching. To this end, the Korean Teaching Observation Protocol (KTOP), which was developed for the purpose of observing and improving science teaching, was utilized. In the first survey, teachers were asked whether they thought each item in the KTOP was important for good science teaching, the extent to which they implemented these items, and the level of difficulty in implementing them. The second survey asked teachers what they believed to be the reasons and solutions for the KTOP items that they had responded as difficult to implement. The responses obtained from 63 teachers in the first survey and 35 teachers in the second survey were categorized based on the characteristics of the responses. The categorized contents were then summarized and discussed for their features. As a result, science teachers responded that all items in KTOP, except for one, are important for good science teaching. However, it was also shown that the level of execution was low in cases where implementation was difficult. For the 13 KTOP items that were considered important but difficult to implement and showed relatively low implementation level, many respondents (69%) attributed the reason to both students and teachers. However, the most common response (60%) was that the teacher should solve those difficulties. From this, it was found that understanding and supporting teachers, as well as enhancing their competencies, are more important for good science teaching than external factors. We hope that this research findings will help to better understand the specific difficulties that science teachers face in their classes and contribute to practical efforts that aim to address these challenges.

• School Mathematics
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• v.4 no.3
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• pp.435-461
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• 2002

In this paper I attempt to survey on the theories of observation and analysis of mathematics classroom discourse. In order to discuss applicability of the theories I look at preservice teachers' observation of mathe-matics classroom and teachers' conception of mathematics lesson. In examining reports from preservice teachers' I identify how they understand mathematics lesson and how the theories can enhance their understanding. Not surprisingly, there are lots of obstacles for teachers to practice mathe-matics educational theories. 1 find some features of their efforts or attempts to overcome the obstacles in an attempt to gain insights into alternative ways of concep-tualizing the methods of observation and analysis through the interview and the discussion with teachers.