• Journal of the Korean Geotechnical Society
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• v.34 no.4
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• pp.37-47
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• 2018

This paper described a results of direct shear test and pullout test by using soil supported by drilled shafts in order to evaluate the effect of relative density and fines content on pullout resistance performance of drilled shafts. The result of direct shear test showed that the variation characteristics of internal friction angle and cohesion could be confirmed quantitatively. The result of pullout test also showed that the effect of relative density and fines content on pullout resistance performance of drilled shafts was confirmed. That is, the contribution of the internal friction angle and cohesion of soils on the pullout resistance performance of drilled shafts was found to vary, when the fines content was about 13% based on results direct shear test and pullout test. Therefore, at design of drilled shafts, the effect of skin friction resistance should be considered on the influence factor of strength parameters ($c-{\phi}$) according to the fines content of soil.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.835-842
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• 2009

DVB-SSP is a new broadcasting system for hybrid satellite communications, which supports mobile handheld systems and fixed terrestrial systems. However, a critical factor must be considered in upper layer decoding which including erasure Reed-Solomon error correction combined with cyclic redundancy check. If there is only one bit error in an IP packet, the entire IP packet is considered as unreliable bytes, even if it contains correct bytes. IF, for example, there is one real byte error, in an If packet of 512 bytes, 511 correct bytes are erased from the frame. Therefore, this paper proposed two kinds of upper layer decoding methods; LLR-based decoding and hybrid decoding. By means of simulation we show that the performance of the proposed decoding algorithm is superior to that of the conventional one.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.643-656
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• 1996

Various light intensity and light quality were treated to oat seedlings to investigate the effect of light on the chlorophyll accumulation and the formation of chlorophyll-protein complexes. The Increase of total chlorophyll accumulation and Chl (chlorophyll) a/b ratio was promoted under H (high intensity) white light during oat chloroplast development when compared to 1 (low intensity) white light. Also H white light was more effective in the formation of chlorophyll-protein complexes associated with PSI CCI and CCII than L white light. The seedlings grown in various right quality caused little changes in total chiorophyl and ChI-a/b ratio when compared to those grown in L white light. The assembly of LHCII trimer was more affected by L white light treatment in the formation of-chlorophyll-protein complexes than red light treatment. The effect of blue light on the relative composition of chlorophyll-protein complexes was similar to that of L white light. Particualrly, blue light was more effective in the synthesis of LHCII monomer than the other light quality at the early stage of greening. When compared to red light, blue light was more effective the increase of chlorophyll accumulation and Chl a/b ratio than 1ight Quality, and light Quality may be in important factor for the regulation of the organization in the chlorophyll-protein complexes curing greening.

• Journal of Environmental Science International
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• v.22 no.6
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• pp.745-759
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• 2013

The characteristics of meteorological conditions and air pollution were investigated in a valley city (Yangsan) on bad visibility days (from 05:00 to 09:00 LST) of the cold half year (November 2008 to April 2009). This analysis was performed using the hourly observed data of meteorological variables (temperature, wind speed and direction, relative humidity, and 2 m and 10 m temperature) and air pollutants ($NO_2$, $SO_2$, $PM_{10}$, and $O_3$). In addition, visibility data based on visual measurements and a visibility meter were used. The bad visibility days were classified into four types: fog, mist, haze, and the mixture (mist+haze). The results showed that the bad visibility days of the four types in the valley city were observed to be more frequently (about 50% of the total study period (99 days except for missing data)) than (27%) those near coastal metropolitan city (Busan). The misty days (39%) in the valley city were the most dominant followed by the hazy (37%), mixture (14%), and foggy days (10%). The visibility degradation on the misty days in Yangsan was closely related to the combined effect of high-level relative humidity due to the accumulation of water vapor from various sources (e.g. river, stream, and vegetation) and strong inversion due to the development of surface radiative cooling within the valley. On the hazy days, the visibility was mainly reduced by the increase in air pollutant (except for $O_3$) concentrations from the dense emission sources under local conditions of weaker winds from the day before and stronger inversion than the misty days. The concentrations of $NO_2$, $PM_{10}$, and $SO_2$ (up to +36 ppb, $+25{\mu}g/m^3$, and +7 ppb) on the hazy days were a factor of 1.4-2.3 higher than those (+25 ppb, $+14{\mu}g/m^3$, and +3 ppb) on the misty days.

• Journal of the Korean earth science society
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• v.33 no.3
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• pp.294-305
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• 2012

Scientific literacy has long been as one of the key goals of science education, and using scientific inquiry in school science has became an important objective to be achieved. The processes of scientific inquiry consist of proposing/developing inquiry question, designing and conducting investigation, collecting, analyzing and interpreting data, and communicating the results. However, most students experience mainly collecting and transforming data in inquiry processes in science class and they are barely exposed to the opportunities of proposing/developing inquiry questions. Middle school earth science preservice teachers participated in this study (N=36) and their abilities of developing inquiry questions were surveyed. Participants' abilities of developing inquiry questions were investigated whether they were enhanced with activities using the Inquiry Questions Development Guide (IQDG). Also, this study was interested in whether there was any relationship between abilities of developing inquiry questions and designing inquiry investigation. The results of this study were as follows; first, the level and preciseness of inquiry questions and its preciseness developed by participating teachers were enhanced after experiencing IQDG. In addition, teachers' dominating inquiry question-types were two: one is a 'relationship-inquiry question' in which students could discover the relationship between results found in the given experimental situations and the other one is a 'why-how inquiry problem' in which students could explore a cause or a process that results in the outcomes. Finally, the higher level of and preciseness the of inquiry questions were identified as an important factor the determined teachers' abilities of designing more logical investigation. A process of proposing/developing inquiry question was identified as one of the most important processes contributing to a success of scientific inquiry investigation.

• Journal of the Korean earth science society
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• v.34 no.7
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• pp.727-737
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• 2013

The purpose of this study was to investigate the middle school students' perception and their learning satisfaction in SMART learning based science instruction. Three types of modules on the solar system and lunar phases unit at the middle school level were developed and lessons on each module were taught to 207 student participants. All participants were provided with tabletPC(iPad2) with iOS5 installed, and using astronomy app Solar Walk, mirroring function, QR code, and Google Presentation, the lessons were carried out both in classroom and at home. The instrument for assessing students' perception on the SMART learning-based instruction was developed based on 4 factors including Self-directed, Motivation, Adaptiveness, and Technology Embedded, with a Likert scale from 1-5 on 20 items. The learning satisfaction survey instrument was originally from Keller's work (1987), and its test items were adapted and modified. To reveal the perception and learning satisfaction about SMART learning-based science lessons, the participants were comparatively analyzed by gender and science achievement levels. Results indicated that male students showed positive perception for the SMART learning-based instruction. Group with higher science achievement scores showed more positive perception of the SMART learning-based instruction in terms of Self-directed and Motivation factor. Also, the learning satisfaction of male students was higher than female students and group with higher academic ability more satisfied with the SMART learning-based instruction than the low group. The results provide implications for future development of programs and help set a direction of increasing the use of a SMART learning-based science in school.

• Journal of Radiation Protection and Research
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• v.20 no.1
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• pp.25-36
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• 1995

The purpose of this research is to develop stereotactic localization and radiation measurement system for the efficient and precise radiosurgery. The algorithm to obtain a 3-D stereotactic coordinates of the target has been developed using a Fisher CT or angio localization. The procedure of stereotactic localization was programmed with PC computer, and consists of three steps: (1) transferring patient images into PC; (2) marking the position of target and reference points of the localizer from the patient image; (3) computing the stereotactic 3-D coordinates of target associated with position information of localizer. Coordinate transformation was quickly done on a real time base. The difference of coordinates computed from between Angio and CT localization method was within 2 mm, which could be generally accepted for the reliability of the localization system developed. We measured dose distribution in small fields of NEC 6 MVX linear accelerator using various detector; ion chamber, film, diode. Specific quantities measured include output factor, percent depth dose (PDD), tissue maximum ratio (TMR), off-axis ratio (OAR). There was small variation of measured data according to the different kinds of detectors used. The overall trends of measured beam data were similar enough to rely on our measurement. The measurement was performed with the use of hand-made spherical water phantom and film for standard arc set-up. We obtained the dose distribution as we expected. In conclusion, PC-based 3-D stereotactic localization system was developed to determine the stereotactic coordinate of the target. A convenient technique for the small field measurement was demonstrated. Those methods will be much helpful for the stereotactic radiosurgery.

• Journal of Radiation Protection and Research
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• v.31 no.4
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• pp.165-171
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• 2006

In Korea, a real-time effective dose measurement system is in development. The system uses 32 high-sensitivity MOSFET dosimeters to measure radiation doses at various organ locations in an anthropomorphic physical phantom. The MOSFET dosimeters are, however, mainly made of silicon and shows some degree of energy and angular dependence especially for low energy photons. This study determines the correction factors to correct for these dependences of the MOSFET dosimeters for accurate measurement of radiation doses at organ locations in the phantom. For this, first, the dose correction factors of MOSFET dosimeters were determined for the energy spectrum in the steam generator channel of the Kori Nuclear Power Plant Unit #1 by Monte Carlo simulations. Then, the results were compared with the dose correction factors from 0.652 MeV and 1.25 MeV mono-energetic photons. The difference of the dose correction factors were found very negligible $(\leq1.5%)$, which in general shows that the dose corrections factors determined from 0.662 MeV and 1.25 MeV can be in a steam general channel head of a nuclear power plant. The measured effective dose was generally found to decrease bit $\sim7%$ when we apply the dose correction factors.

• Journal of The Korean Association For Science Education
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• v.37 no.3
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• pp.395-405
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• 2017

This study aims to investigate the effects of socioscientific issues (SSI) instruction on promoting college students' character and values as citizens, and to compare the effects based on the psychological factor - idiocentrism and allocentrism. Thirty-one college students who enrolled in the SSI course participated in this study. The SSI course provided the students with opportunities to explore various aspects of five topics, to express and share their own opinions, and to identify reasonable alternatives. The students with distinct tendencies were classified into two groups (i.e. idiocentric and allocentric groups) based on the personal value orientation scores before the instruction, and they responded to the questionnaire to examine their character and values as citizens before and after the instruction. The results showed that the students' social and moral compassion and socioscientific accountability improved significantly after the SSI course. The overall effects of the SSI program on students' character and values were not significantly different between two groups. However, the post-mean score of the allocentric group in socioscientific accountability was higher than the one of the idiocentric group. This study shows that SSI instruction could positively affect character development regardless of psychological tendencies, and could be implemented in the science classroom as a good instructional approach to integrating science education and character education.

• Journal of The Korean Association For Science Education
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• v.39 no.6
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• pp.755-765
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• 2019

This study aims to develop the scales to measure the innovation configurations of Science. Technology, Engineering, Art and Mathematics (STEAM) from the perspective of elementary school teachers and investigates the effect of the innovation configurations and related environmental factors on the usage levels of STEAM based on the newly developed scales for the innovation configurations of STEAM. The scales for the innovation configurations of STEAM are based on analyzing the various previous studies and in-depth interviews and consist of four sub-configurations: The 'Preparation,' 'Design,' 'Implementation,' and 'Evaluation.' The innovation configurations of STEAM was investigated with the developed scales through 266 teachers who are leading STEAM school teachers, are involved in STEAM research group, or are implementing STEAM in general schools. The final 19 questionnaires for the scale of the innovation configuration of STEAM are confirmed with exploratory factor analysis and reliability analysis. In order to examine the relationship between the innovation configurations and levels of use, the direct relationship between four sub-configurations and the usage levels of STEAM and the effect of environmental factors on the innovation configuration and the usage levels of STEAM have been conducted and their interactions are considered. The results show that 'Implementation' in the innovation configurations of STEAM and 'STEAM training experience' are most important factors to improve the usage levels of STEAM for elementary school teachers. It implies that the scales are very helpful in improving as well as figuring out the current innovation configurations of STEAM.