• Journal of Energy Engineering
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• v.13 no.1
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• pp.75-81
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• 2004

ZZFCa sorbents for hot gas desulfurization in IGCC were prepared by adding calcium oxide to ZZF sorbent in order to improve its attrition resistance in this study. ASTM attrition test for the sorbent was performed at several different weight percentages of CaO to investigate the attrition characteristics of ZBFCa sorbents as a function of CaO content. Attrition index of ZZF without CaO was 28.3% and its collected attrition index was 10.8％. ZZFCa-3 containing 3 wt% CaO showed the lowest attrition index (AI=17.3％, CAI=8.8％) in the test. From the results of SEM morphologies and particle size distribution measurements, ZZFCa-3 maintained a fine shape and a desirable average particle size even after attrition test. In the experiments of sulfidation/regeneration for ZZFCa-3 sorbent concentration of hydrogen sulfide in coal gas was lowered from 10000 ppm to below 1 ppm. Sulfur removing capacity was about 28.8 g S/100 g sorbent. Neither formation of CaSO$_4$ was observed in XRD measurement nor SO$_2$ slippage was observed during sulfidation process.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.538-541
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• 2005

Tidal flats develop along the south coast ofthe Korean peninsula. These areas are famous for sea farming. Specially, strong and coherent radar backscattering signals are observed over oyster sea farms that consist of artificial structures. Tide height in oyster farm is possible to measure by using interferometric phase and intensity of SAR data. It is assumed that the radar signals from oyster farm could be considered as double-bouncing returns by vertical and horizontal bars. But, detailed backscattering mechanism and polarimetric characteristics in oyster farm had not been well studied. We could not demonstrate whether the assumption is correct or not and exactly understand what the properties of back scattering were in oyster farm without full polarimetric data. The results of AIRSAR L-band POLSAR data, experiments in laboratory and JERS-l images are discussed. We carried out an experiment simulating a target structure using vector network analyser (Y.N.A.) in an anechoic chamber at Niigata University. Radar returns from vertical poles are stronger than those from horizontal poles by 10.5 dB. Single bounce components were as strong as double bounce components and more sensitive to antenna look direction. Double bounce components show quasi-linear relation with height of vertical poles. As black absorber replaced AI-plate in bottom surface, double bounce in vertical pole decreased. It is observed that not all oyster farms are characterized by double bounced scattering in AIRSAR data. The image intensity of the double bounce dominant oyster farm was investigated with respect to that of oyster farm dominated by single bounce in JERS-l SAR data. The image intensity model results in a correlation coefficient (R2 ) of 0.78 in double bounce dominant area while that of 0.54 in single bouncing dominant area. This shows that double bounce dominant area should be selected for water height measurement using In8AR technique.

• Korean Journal of Community Nutrition
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• v.16 no.5
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• pp.548-558
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• 2011

The purpose of this study was to compare eating habits and food attitudes between depressed and normal adults. The subjects were selected (n = 6217) from those who participated in the 2008 Korean National Health and Nutrition Examination Survey (KNHANES IV). The subjects were divided into the depressed (DG, n = 841) and normal groups (NG, n = 3969). DG was those who have depression now or who have experienced depressing feelings more than two weeks or per year. The general characteristics, anthropometric measurement, eating habits, the dietary guideline recognition and practices were compared by using chi-square test and t-test. Also the partial correlations were analyzed by SAS (Statistical analysis system, version 9.1) program. There was a significantly higher rate of DG among the female (74.32%), with low education (44.6%) and low-income (32.0%) subjects (p < 0.001). DG showed significantly lower snacking and dining out. There was significantly higher rate of DG who responded "none" in frequency of snack (27.10%) and dining out (29.50%) (p < 0.001). Also DG showed significantly lower rate of the subjects who ate with the family than NG. Also, DG showed significantly lower dietary guideline recognition level and practice than NG. Correlation between depression symptom and various factors showed that positive correlation with low snack intake and dining out frequencies. However, correlation was relatively weak. In conclusion, eating habits and recognition levels and practice of dietary guidelines of DG were significantly different from NG. DG showed significantly lower frequencies of snack, dining out, and eating with family.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.4
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• pp.27-43
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• 1990

This study aimed at developing a generalized model on the estimation of the long - term run - off volume for practical purpose. During the research period of last 3 years( 1986-1988), 3 types of estimation model on the long - term run - off volume(Effective rainfall model, unit hydrograph model and barne's model for dry season) had been developed by the author. In this study, through regressional analysis between determinant factors (bi of effective rainfall model, ai of unit hydrograph model and Wi of barne's model) and catchment characteris- tics(catchment area, distance round the catchment area, massing degree coefficient, river - exte- nsion, river - slope, river - density, infiltration of Watershed) of 11 test case areas by multiple regressional method, a new methodology on the derivation of determinant factors from catchment characteristics in the watershed areas having no hydrological station was developed. Therefore, in the resulting step, estimation equations on run - off volume for practical purpose of which input facor is only rainfall were developed. In the next stage, the derived equations were applied on the Kang - and Namgye - river catchment areas for checking of their goodness. The test results were as follows ; 1. In Kang - river area, average relative estimation errors of 72 hydrographs and of continuous daily run - off volume for 245 days( 1/5/1982 - 31/12) were calculated as 6.09%, 9.58% respectively. 2. In Namgye - river area, average relative estimation errors of 65 hydrographs and of conti- nuous daily run - off volume for 2fl days(5/4/1980-31/12) were 5.68%, 10.5% respectively. In both cases, relative estimation error was averaged as 7.96%, and so, the methodology in this study might be hetter organized than Kaziyama's formula when comparing with the relative error of the latter, 24~54%. However, two case studies cannot be the base materials enough for the full generalization of the model. So, in the future studies, many test case studies of this model should he carries out in the various catchment areas for making its generalization.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.115-121
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• 2020

This study aims to develop a framework of structural scenarios for chatbot docent that supports visitors' activities in science centers and museums, and to suggest the application examples. For this study, the author adapted Focus Group Interview. As a result, the frameworks of scenarios could be categorized into the Collection of Science and Technology(CST) and Inquiry-Based Exhibition(IBE). These frameworks had dimensions of the primary and storytelling in common. Especially, framework of IBE scenario was added the usage dimension considering the characteristics of interaction between exhibits and visitors. This study could be basic materials for AI chatbot to support exhibition descriptions using the built data, and is expected to be help develop a more visitor-oriented scenarios of activities.

• The Journal of Korean Association of Computer Education
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• v.23 no.2
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• pp.1-11
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• 2020

As software and artificial intelligence education became more and more important, in December 2019, the Ministry of Science and ICT announced plans to expand software and AI education to mandatory education in elementary and secondary schools by 2022. In addition to elementary and secondary schools, most universities are actively engaged in software education for computer non-majors, but research on coding education for computer non-majors is insufficient. The purpose of this paper is to find an efficient teaching and learning method for coding education for computer non-majors. Nowadays, college students, called Millennial and Generation Z, prefer visual information and are familiar with computers as digital natives. Based on these characteristics, this study examined the visual literacy and thinking styles of college students and then examined whether the students' visual literacy and thinking styles influenced coding-based problem solving in coding subjects. Based on this, this paper proposes an alternative to do programming education more efficiently for students who are new to coding.

• The KIPS Transactions:PartC
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• v.11C no.5
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• pp.697-702
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• 2004

As for the digital content, a reproduction is easy and manuscript is identical with original copy. Because of these characteristics, there are difficulties on prevention of an illegal reproduction and an illegal currency. In recent days various digital content service systems based on a web are commercialized. An appropriate copyright protection technology is required so that these systems develop as a profit model. Generally we use encrypted digital content transmission method for the copyright protection on a web base system. At the time of this, it is increased sire of encrypted digital content. As for this, it be increased time required on an execution process. Therefore, a design of the system that considered a execution time and a security is required. In this study, we designed the digital content transmission system that considered execution time and a security through a partial encryption based on a digital content copyright management technique. Also we evaluated performance of a proposed system through analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.40-40
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• 2010

Structural, electrical, and optical properties of atomic layer-controlled AI-doped ZnO (ZnO:Al) films grown on glass by atomic layer deposition (ALD) were characterized with various $Al_2O_3$ film contents for use as transparent electrodes. Unlike films made using sputtering methods, the diffraction peak position of the films grown by ALD based on alternate self-limiting surface chemical reactions moved progressively to a wider angle (red shift) with increasing $Al_2O_3$ film content, which seems to be evidence of Zn substitution in the film by layer-by-layer growth. By adjusting the $Al_2O_3$ film content, the electrical resistivity of ZnO:Al film with the $Al_2O_3$ film content of 2.96% reached the lowest electrical resistivity of $9.80{\times}10^{-4}\Omega{\cdot}cm$, in which the carrier mobility, carrier concentration, and optical transmittance were $11.20\;cm^2V^{-1}s^{-1}$, $5.69{\times}10^{20}\;cm^{-3}$, and 94.23%, respectively. Moreover, the estimated figure of merit value for the transparent conductive oxide applications from our best sample was $7.7\;m{\Omega}^{-1}$.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.1
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• pp.42-52
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• 2014

The aim of this investigation was to assess the relationship between food habits and nutrient intake in college female students. Nutrient intakes of 149 female subjects aged 19.3 y were determined by using 24-hr recall. The questionnaire included general characteristics and food habits (frequency of breakfast and fast food intake). Body composition was determined by bioim- pedance analysis. Nutrient analysis was performed with Can pro software. Statistics were generated using SAS 9.3 (SAS Institute, Cary, NC). Mean intake of energy, fiber, calcium, potassium. vitamin $B_2$ and vitamin C by the subjects ware below KDRIs. The nutrients for which the largest proportion of subjects showed inadequate intakes (less than the RI or AI) were potassium, calcium, vitamin C and fiber. Subjects that consumed fast food ${\leq}6$ times showed significantly lower intakes of calcium, potassium, fiber, vitamin A, vitamin $B_6$ and vitamin C. Subjects who skipped breakfast more frequently showed significantly lower intakes of energy, carbohydrate, fiber, calcium, iron, potassium, vitamin $B_2$ and vitamin C than subjects who ate breakfast more frequently. This is strong evidence that higher intakes of nutrients such as potassium, fiber, and calcium are associated with increased frequency of eating breakfast or decreased frequency of eating fast food. Low calcium, fiber, and potassium intakes may thus lead to chronic diseases. Nutrition education can be an important facilitator for improving nutrient intakes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.3
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• pp.103-111
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• 1998

This paper reports the sediment geochemistry and its relation to the grain size distribution in Kyeonggi Bay, Korea. Sediment samples were collected from 90 stations during the cruise crossing the bay in December 1995. Variables investigated were the sediment grain size, organic carbon content, and concentrations of AI, Fe, Mn, V, Co, Ni, Cr, Zn and Cu in the sediment. We followed the change in these variables by comparing the data obtained from this region in 1981. Distribution pattern of sediment grain size was modified from that in 1981 in some places. Near the Shihwa Dike which was completed in 1994, sediment had got finer grained. Sediment facies changed from fine to mixed facies near Youngjong Island where the tidal flat has been reclaimed for airport construction. Contents of organic matter and metals in the sediment were mostly dependent upon the sediment grain size, but an exception was found in the harbor area. The sediment in the Incheon North Harbor showed higher accumulation of organic matter and metals such as Ni, Cr, Zn and Cu.