• Journal of the Korea Organic Resources Recycling Association
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• v.6 no.1
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• pp.53-66
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• 1998

This study was carried out to investigate the typical composition of food waste from municipal solid wastes (MSW) and unit food waste generation rates from different sources in the model cities and to study the food waste management system from unit household to composting facilities. The annual average food waste composition of MSW was determined as 49% in Taejon and 52% in Chungnam Province, respectively. No big difference in food waste composition was found among the different sources. Since the paper waste generally occupied the half of food waste, over 75% of MSW was found to be compostable or biodegradable. Per capita food waste generation rate, 200~250g/capita day was determined by the direct measurement from 32 households, while 380g/capita day for Chungnam Province and 400 g/capita day for Taejon were estimated by the load count analysis In the sanitary landfills. This difference means people contribute generating food waste at outside house approximately twice as much as that at inside house. Per capita food waste generation rates from several sources were determined as follows; 166~215g/capita day at municipalities, 400g/visitor day at a first class hotel, 170g/student day at a university restaurant. Food waste generation from restaurant was strongly dependant upon it's level or quality; 670g/capita day at the high level restaurant, 190g/capita day at the middle class and 60 g/capita day at the lower class restaurant. The food waste reduction rate in a In situ fermentor showed 30~40g/kg day.

• Korean Journal of Remote Sensing
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• v.30 no.4
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• pp.511-524
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• 2014

In this study, we investigated the statistical occupations and interannual variations of land cover types over Northeast Asian region using the 12 years (2001-2012) MODerate Resolution Imaging Spectroradiometer(MODIS) land cover data sets. The spatial resolution and land cover types of MODIS land cover data sets are 500 m and 17, respectively. The 12-year average shows that more than 80% of the analysis region is covered by only 3 types of land cover, cropland (36.96%), grasslands (23.14%) and mixed forests (22.97%). Whereas, only minor portion is covered by cropland/natural vegetation mosaics (6.09%), deciduous broadleaf forests (4.26%), urban and built-up (2.46%) and savannas (1.54%). Although sampling period is small, the regression analysis showed that the occupations of evergreen needleleaf forests, deciduous broadleaf forests and mixed forests are increasing but the occupations of woody savannas and savannas are decreasing. In general, the pixels where the land cover types are classified differently with year are amount to more than 10%. And the interannual variations in the occupations of land cover types are most prominent in cropland (1.41%), mixed forests (0.82%) and grasslands (0.73%). In addition, the percentage of pixels classified as 1 type for 12 years is only 57% and the other pixels are classified as more than 2 types, even 9 types. The annual changes in the classification of land cover types are mainly occurred at the almost entire region, except for the eastern and northwestern parts of China, where the single type of land cover located. When we take into consider the time scale needed for the land cover changes, the results indicate that the MODIS land cover data sets over the Northeast Asian region should be used with caution.

• Journal of Broadcast Engineering
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• v.17 no.2
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• pp.374-387
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• 2012

In this paper, we implement a new hardware for finding the significant coefficients of a digital hologram and ciphering them using discrete wavelet packet transform (DWPT). Discrete wavelet transform (DWT) and packetization of subbands is used, and the adopted ciphering technique can encrypt the subbands with various robustness based on the level of the wavelet transform and the threshold of subband energy. The hologram encryption consists of two parts; the first is to process DWPT, and the second is to encrypt the coefficients. We propose a lifting based hardware architecture for fast DWPT and block ciphering system with multi-mode for the various types of encryption. The unit cell which calculates the repeated arithmetic with the same structure is proposed and then it is expanded to the lifting kernel hardware. The block ciphering system is configured with three block cipher, AES, SEED and 3DES and encrypt and decrypt data with minimal latency time(minimum 128 clocks, maximum 256 clock) in real time. The information of a digital hologram can be hided by encrypting 0.032% data of all. The implemented hardware used about 200K gates in $0.25{\mu}m$ CMOS library and was stably operated with 165MHz clock frequency in timing simulation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.4
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• pp.705-713
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• 2016

For the soft ground construction, the factors not considered in the design stage occurs in the construction stage so that they cause the increase of the construction cost due to the structural stability and the design change. The subject of the study is the construction section of the industrial complex access road made in the Ochang region of Chungcheongbuk-do. The study is concerned with selecting the soft ground handling method such as the replacement method using rock debris and the surcharge reflecting the service load as the soft ground handling measure and analyzing the effect of reducing the construction cost with the stability of structures and the reduction of the construction period. The soft ground in the study section consists of sandy and cohesive soil and is 2.4m to 5.5m deep. It is distributed unevenly between the 1.5m to 5.9m stratums under the ground surface. Settlement is not serious, but the future uneven settlement and difference are expected so that the future settlement behavior is estimated by analyzing the site measurement results after the soft ground treatment. Moreover, in consideration of the regional characteristics and economic efficiency, soil with good quality is replaced with rock debris as the replacement material so that 29% of the construction cost is reduced due to the increase of stability and the reduction of duration. If the estimation of the dispersion of the pore water pressure within the dam body and the change of the underground water level and the relation of the actually measured soft ground with consolidation is studied further on the basis of the study, it is expected that the behavior of the soft ground will be correctly estimated in various site conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.973-982
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• 2012

Crop safety in heavy metal contaminated agricultural field has been a critical issue in Korea and various remediation methods are proposed for minimizing heavy metal transfer from soil to crops. The main objective of this research was to evaluate remediation efficiency of two chemical amendments, lime and steel slag, and to decide extractant for assessing bioavailability of heavy metals. In order to select optimum extractant for evaluating bioavailability of heavy metals, four different single extractants, HCl, DTPA, $CaCl_2$, $NH_4NO_3$, and sequential extraction method were examined. Both chemical amendments showed high immobilization effect for Cd (66%, $33.62mg\;kg^{-1}$) and Pb (74%, $27.65mg\;kg^{-1}$) in soil by HCl extractant. In terms of heavy metal concentration in rice grains, concentrations for Cd (77%, $0.023mg\;kg^{-1}$) and Pb (82%, $0.039mg\;kg^{-1}$) decreased, with addition of chemical amendments. HCl, DTPA, and sequential extractant showed the higher correlation between heavy metal concentration in soil and crops than others. These results indicated that they could be used for assessing bioavailability of heavy metals.

• Journal of Science Education
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• v.39 no.2
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• pp.278-289
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• 2015

The purpose of this study is to analyze selection methods of gifted students. This study focuses on the understanding the characteristics of gifted students in accordance with the selection methods, i.e. the examination selection and automatic promotion by analyzing and comparing the academic emotion, meta-cognition, and self-efficacy between gifted students selected according to the selection methods. Moreover, for the purpose of the effective gifted education, this study aims to arrange a reasonable basis for the discrimination and selection of gifted students. The results of this study were as follows. First, there was no meaningful difference between gifted students selected by an examination and promoted automatically in view of academic emotion, meta-cognition, and self-efficacy of gifted students. It is determined that there is no difference between the effects of selection methods under the condition of the same group of gifted students. Second, regarding the academic emotion of gifted students, there is no significant difference in both the elementary and middle school in case of examination selection. However, in case of the automatic promotion, the academic emotion of gifted students promoted automatically in the gifted education center was higher than that of the gifted students in the gifted class (p < .05). Regarding the meta-cognitive skill, there is no difference in the elementary school between the selection methods. In case of the examination selection in the middle school, the meta-cognitive skill of male students of the gifted education center was higher than that of the female and gifted class students (p < .05). In case of the automatic promotion in the middle school, the meta-cognitive skill of students of the gifted education center was higher than that of students of the gifted class (p < .05). As for the case of self-efficacy, there were no differences between the selection methods. In the automatic promotion, self-efficacy of students of the gifted education center was higher than that of students of the gifted class (p < .05).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.541-547
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• 2017

In Yongwon channel, its natural flow of seawater is blocked by the construction of Busan Newport including the container berth. The channel was transformed into a narrow and long one, where it is possible that ships are only allowed to pass through the north-side channel of Gyeonmado located at the point of river mouth to Songjeongcheon. So it is considered that the changes in the terrain characteristics of Yongwon channel is likely to alter the circulation of sea water, thereby changing its water quality. Contaminants are accumulated from the sediment release. In this study, before and after dredging the sediment release test was performed. As a result, after the sediment dredging is performed, the reduction rate was higher at the same point. The results show that the water quality can be improved by dredging. Each group (A~C) reduction rate of the evaluation of the reduction rate of 4.64% T-N, 18.00%, 18.59%, respectively. T-P rate of 24.75% reduction, 24.17%, 44.08%, respectively. COD reduction rate was 18.57%, 19.76%, 38.08%, respectively. These results can be used as basic data for controlling the contamination by dredging in Yongwon channel.

• Economic and Environmental Geology
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• v.29 no.2
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• pp.129-138
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• 1996

The ores of the Bobae mine are mainly composed of sericite and quartz, and with appreciable amount of some other minerals such as andalusite. pyrophyllite, and albite, etc.. Sericite occurs in various a1teration zones having different crystal size and habit. Sericites can be c1assified into two types based on the crystal size; fine-grained and coarse-grained sericite. Fine-grained sericite occurs as an aggregate. Mineralogical characterizations of both types of sericites have been studied with various methods. Lattice parameters of two types of sericites occurred in various alteration zones are almost identical. but b parameter of coarse-grained sericite appears to be slight1y bigger than that of fine-grained aggregates. Average structural formula of fine- and coarse-grained sericite is $K_{1.44}Al_{3.86}(Si_{6.35}Al_{1.65})O_{20}(OH)_4$ and $K_{1.71}Al_{3.82}(Si_{6.20}Al_{1.80})O_{20}(OH)_4$, respectively. Structural formulae of coarse-grained sericites are close to that of muscovite. Infrared spectra show that there is slight distinction between sericites occurred in andalusite-pyrophyllite zone and other subzones. IR spectra of sericites due to Si-O vibration ($540{\sim}530cm^{-1}$) tend to shift to smaller wavenumber side from center to outer alteration zone. All samples have litt1e or no interstratified minerals. and this is demonstrated by Ir and DTA-TG results. It indicates that the Bobae mine is formed at relatively high temperature. That the ratio of quartz to sericite in ores varies greatly indicates that several discontinuous hydrothermal alteration processes have been involved.

• Journal of Conservation Science
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• v.26 no.1
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• pp.25-32
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• 2010

The yellowing is always occurred phenomena in epoxy restoration material of antic-ceramics. For re-restoration of remains with epoxy restoration material, the epoxy elimination step is the first one in all course of restoration In this paper, the chemically elimination treatments methods of epoxy in various antic-ceramics were discussed. We fabricated the epoxy elimination material for antic-ceramics restoration which were made up Dichloromethane and Dichlormethane based Dimethylformamide solution. Dichloromethane and Dichloromethane + Dimethylformamide mixture were applied to epoxy in various antic-ceramic sample. Particularly, Dichloromethane + Dimethylformamide solution had the best result in variation of color change, gloss, vending strength, weight, exfoliation time test after deposition in this solution. Dichloromrthane had the volume increase characteristics for epoxy material and Dimethylformamide had the mollification ones. So, Dichloromathane increased exfoliation in approximal surface of the epoxy material and antic ceramic, and Dimethylformamide decreased the surface hardness of epoxy. In this result, epoxy material even inside of ceramic that have very weak inside bonding is adaptable and stable eliminated. And in order to show the perfect elimination of this material, we successfully dissolve the epoxy restoration material in one antic pottery that is in one university museum's possession using this mixture. So, there is guarantee in the eternity and stabilization of restoration for antic-ceramics.

• Archives of design research
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• v.18 no.1 s.59
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• pp.175-184
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• 2005

With the rapid progress of the aging society in Korea, the silver generation is emerging as another class of users in the new population structure. This is a social issue to be dealt with, and the effect of such a change is being observed dearly in the design area. In addition, there are increasing demands for consideration of minor groups of users including the elderly, the disabled, the left-handed, children and pregnant women and nursing mothers, who have been treated as the weak. Such a human-centered idea may be the manifestation of the recovery of humanity and the self-realization of human beings through experiences and reflections of the industrial society of the past. The present study examined the tendency of design standardization centering on universal design, which has emerged in response to user-centered social needs, and suggested general considerations for the necessity of introducing such standards. These days the meanings of standardization are not limited to quality, performance, safety and economic aspect. Standardization is required to consider the diversity and the welfare of human beings. In addition, one of the important functions of standardization is to provide designers with important clues and guidelines for designing. In reality, however, standardization has been rejected by the circle of design for the reason that it deters free creation, so research on the introduction of standardization has been at standstill. As ISO/IEC Guide71 was published in November 2001, based on which, the Korea Standards Association established KS A ISO/IEC Guide71 without changing its contents. In companies' manufacturing activities, the progress of standardization in connection to universal design is growing more important. However, usefulness and interchangeability for the absolute majority resulting from standardization are incomparable. Lastly, the realization of universal design requires human-centered design mind, based on users' experiences and needs, the characteristics of the human bodies and inconvenient elements rather than standards for the sake of standardization.