• Earthquakes and Structures
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• v.13 no.1
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• pp.59-66
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• 2017

Modern seismic codes rely on performance-based seismic design methodology which requires that the structures withstand inelastic deformation. Many studies have focused on the inelastic deformation ratio evaluation (ratio between the inelastic and elastic maximum lateral displacement demands) for various inelastic spectra. This paper investigates the inelastic response spectra through the ductility demand ${\mu}$, the yield strength reduction factor $R_y$, and the inelastic deformation ratio. They depend on the vibration period T, the post-to-preyield stiffness ratio ${\alpha}$, the peak ground acceleration (PGA), and the normalized yield strength coefficient ${\eta}$ (ratio of yield strength coefficient divided by the PGA). A new inelastic deformation ratio $C_{\eta}$ is defined; it is related to the capacity curve (pushover curve) through the coefficient (${\eta}$) and the ratio (${\alpha}$) that are used as control parameters. A set of 140 real ground motions is selected. The structures are bilinear inelastic single degree of freedom systems (SDOF). The sensitivity of the resulting inelastic deformation ratio mean values is discussed for different levels of normalized yield strength coefficient. The influence of vibration period T, post-to-preyield stiffness ratio ${\alpha}$, normalized yield strength coefficient ${\eta}$, earthquake magnitude, ruptures distance (i.e., to fault rupture) and site conditions is also investigated. A regression analysis leads to simplified expressions of this inelastic deformation ratio. These simplified equations estimate the inelastic deformation ratio for structures, which is a key parameter for design or evaluation. The results show that, for a given level of normalized yield strength coefficient, these inelastic displacement ratios become non sensitive to none of the rupture distance, the earthquake magnitude or the site class. Furthermore, they show that the post-to-preyield stiffness has a negligible effect on the inelastic deformation ratio if the normalized yield strength coefficient is greater than unity.

• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.65-72
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• 2016

ORC system was designed and constructed for utilizing the heat of the exhaust gas and coolant released from the gas engine which was modified to use natural gas as a fuel. In this paper the components of the ORC system were designed and manufactured based on measured data of the gas engine. The components are composed of two plate heat exchanger, the 5kW-class expander and multi stage centrifugal pump. The thermodynamic performance of the ORC system was analyzed by using the electric heater. Also, the developed ORC system was implemented to modified natural gas engine. Two gas engines were used to supply heat to the ORC system. As a result of test bench, when the heat source temperature is $110^{\circ}C$ expander shaft power, the pressure ratio and cycle efficiency is 5.22kW, 7.41, 9.09%. As a result of field test, when the heat source temperature is $86^{\circ}C$ expander shaft power, the pressure ratio and cycle efficiency is 2kW, 3.75, 6.45%.

• Restorative Dentistry and Endodontics
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• v.34 no.6
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• pp.467-476
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• 2009

The aim of this study was to measure the dentinal tubular fluid flow (DFF) during and after amalgam and composite restorations. A newly designed fluid flow measurement instrument was made. A third molar cut at 3 mm apical from the CEJ was connected to the flow measuring device under a hydrostatic pressure of 15 $cmH_2O$. Class I cavity was prepared and restored with either amalgam (Copalite varnish and Bestaloy) or composite (Z-250 with ScotchBond MultiPurpose: MP, Single Bond 2: SB, Clearfil SE Bond: CE and Easy Bond: EB as bonding systems). The DFF was measured from the intact tooth state through restoration procedures to 30 minutes after restoration, and re-measured at 3 and 7days after restoration. Inward fluid flow (IF) during cavity preparation was followed by outward flow (OF) after preparation, In amalgam restoration, the OF changed to IF during amalgam filling and slight OF followed after finishing. In composite restoration, application CE and EB showed a continuous OF and air-dry increased rapidly the OF until light-curing, whereas in MP and SB, rinse and dry caused IF and OF, respectively. Application of hydrophobic bonding resin in MP and CE caused a decrease in flow rate or even slight IF. Light-curing of adhesive and composite showed an abrupt IF. There was no statistically significant difference in the reduction of DFF among the materials at 30 min. 3 and 7 days after restoration (p > 0.05).

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.339-345
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• 2011

BACKGROUND: Recently in Korea, the import of agricultural products is rising due to the increasing amount of trade. Unregistered pesticides, allidochlor, propachlor, propham, cycloate, diallate and pebulate are widely used as pesticides for rice cultivation in foreign countries, while they are not registered in Korea. Therefore, the residue amount of imported agri-foods should be verified using the proper official analytical method for each of them that has not registered in Korea. METHODS AND RESULTS: This work was conducted to apply the official method of Korea Food & Drug Administration (KFDA) for determining multi class pesticide multiresidues in agricultural commodities. Brown rice and orange which have different characteristics as a matrix were selected as representative samples for residue analysis. The recoveries of cycloate, diallate and pebulate by GC/MS in fortified brown rice and orange with levels of 0.04~0.4 mg/kg were ranged from 82.8% to 110.3%. The quantification limits of three pesticides in brown rice and orange were 0.04 mg/kg. CONCLUSION: As a result, this method can surely be used as an official method for routine analysis of unregistered pesticides in Korea for imported agri-food.

• Journal of Navigation and Port Research
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• v.35 no.6
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• pp.477-482
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• 2011

Solar flares have the 11-year cycle and release a large energy which may produce coronal mass ejections (CME). The NOAA (National Oceanic and Atmospheric Administration) predicted that the sun spot activity will be maximized in 2013-2014. A strong solar flare can cause the disturbance of global positioning system including various communication of TV, radio broadcasting. The actual solar storm in 1989 caused power outages in Canada during 9 hours and about 600 million people had experienced a blackout. Such a solar storm can shorten the GPS satellite's life span about 5 to 10 years which can resulted in economic loss considering the amount of multi-billion won. This paper analyzed the influence of recent X-class solar storm occurred on 15th of February about 10:45 this year that was reached Korea (Bohyun observatory) on 18th of February about 10:30 (01:30 - UTC), and compared with the data before and after a week. The proton data of 18th of February considered that the solar storm reached on earth showed a fluctuation compared to the data before and after a week. The positioning results at Daejeon and Seoul of Korea also showed higher positioning error compared to the data before and after a week results.

• The KIPS Transactions:PartB
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• v.15B no.1
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• pp.25-36
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• 2008

In this paper, we present a robust hand recognition approach to sudden illumination changes. The proposed approach constructs a background model with respect to hue and hue gradient in HSI color space and extracts a foreground hand region from an input image using the background subtraction method. Eighteen features are defined for a hand pose and multi-class SVM(Support Vector Machine) approach is applied to learn and classify hand poses based on eighteen features. The proposed approach robustly extracts the contour of a hand with variations in illumination by applying the hue gradient into the background subtraction. A hand pose is defined by two Eigen values which are normalized by the size of OBB(Object-Oriented Bounding Box), and sixteen feature values which represent the number of hand contour points included in each subrange of OBB. We compared the RGB-based background subtraction, hue-based background subtraction and the proposed approach with sudden illumination changes and proved the robustness of the proposed approach. In the experiment, we built a hand pose training model from 2,700 sample hand images of six subjects which represent nine numerical numbers from one to nine. Our implementation result shows 92.6% of successful recognition rate for 1,620 hand images with various lighting condition using the training model.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.175-183
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• 2015

The proposed algorithm consists of two stages: the learning and synthesis stages. At the learning stage, we first collect various high-resolution (HR)-low-resolution (LR) text image pairs, and quantize the LR images, and extract HR-LR block pairs. Based on quantized LR blocks, the LR-HR block pairs are clustered into a pre-determined number of classes. For each class, an optimal 2D-FIR filter is computed, and it is stored into a dictionary with the corresponding LR block for indexing. At the synthesis stage, each quantized LR block in an input LR image is compared with every LR block in the dictionary, and the FIR filter of the best-matched LR block is selected. Finally, a HR block is synthesized with the chosen filter, and a final HR image is produced. Also, in order to cope with noisy environment, we generate multiple dictionaries according to noise level at the learning stage. So, the dictionary corresponding to the noise level of the input image is chosen, and a final HR image is produced using the selected dictionary. Experimental results show that the proposed algorithm outperforms the previous works for noisy images as well as noise-free images.

• Journal of agriculture & life science
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• v.46 no.4
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• pp.57-68
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• 2012

This study was conducted to provide basic data for the effective conservation and management in the black pine(Pinus thunbergii) stand which is located in the eastern coast of Gyeongsangbuk-do where the fragmentation of vegetation has been caused by the exploitation and the increase of tourists, and installed the seventy study sites($20{\times}20m$) in the dominant black pine stand. The black pine stand was classified into three groups(P. thunbergii - P. densiflora community, P. thunbergii - Robinia pseudoacacia community, P. thunbergii - P. densiflora-Celtis sinensis community) by a cluster analysis. As a result of Multi-Response Permutation Procedures test, there is significance among the communities. Pinus densiflora, Callicarpa japonica, Juniperus rigida, Rhododendron yedoense for. poukhanense etc. nineteen species were significant by indicator species analysis. The population structure of black pine stand showed that the class of diameter 12 to 26 cm was dominance, which had the inverse hump-shape pattern. Species diversity index(H') of investigated ranged from $1.033{\pm}0.234$ to $1.629{\pm}0.226$ in the woody layer group and from $2.448{\pm}0.457$ to $2.545{\pm}0.318$ $2.174{\pm}0.333$ in the herb layer group.

• Korean Journal of Social Welfare Studies
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• v.49 no.1
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• pp.51-83
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• 2018

This study examines whether the widening gap between income groups is worsening in the distribution of time use, similar to the worsening of income distribution after the IMF. To do this, we conducted multilevel analysis (HLM) on six countries including France, the Netherlands, Spain, the United Kingdom, the United States and Korea. The results of the analysis are as follows. First, in all countries, low income groups have a longer paid working time and shorter leisure time. Second, the low income groups in Korea have the longest paid work time and the shortest leisure time, the lowest level of work-leisure balance, and this aspect has not recovered since the IMF. Third, as the result of multilevel analysis, the lower the household income, the more time paid labor increased and the work-leisure balance decreased. Fourth, while average annual working hours increase paid working time, the expansion of family policy expenditure, redistribution policy and income maintenance policy has reduced it. Fifth, the annual average working hours decreased the work-leisure balance, but the family policy expenditure, the redistribution policy and the income guarantee policy increased the work-leisure balance. The significance of this study is that after the IMF, not only the income distribution but also the inequality among the income class in time use has deepened. Based on the results of the research this study suggests the reinforcement of labor time regulation, the activation of parental leave system, the realization of the income replacement rate, the expansion of the policy related to income redistribution, and the complementary development of the income guarantee and the time guarantee policy as the policy intervention strategy that restructures time.

• Korean Journal of Social Welfare Studies
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• v.44 no.3
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• pp.57-83
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• 2013

There has neither been enough research on how to approach the concept of active aging through an integrated view nor an examination to verify the relationship between preparation for old age and active aging in later life. Therefore, this research aims to verify that the elderly, who have prepared for their later life, affected their active aged life. In addition, by setting up self-efficacy and social support as mediator in the research model, this paper looks into the psycho-social resource mechanism of the relationship in depth. In order to verify the correlation of two variables, the Seoul welfare panel data, a mediating model structured by psycho-social resources created by Seoul welfare foundation in 2010, was used. The total sample size was a group of 1,492 elders aged over 65. When it came to our research methods, structured equation analysis was applied to verify the mediating effect and theoretical background. The results revealed that physical preparation, financial preparation, social preparation and leisure preparation directly affected their active aging level positively, thus, psycho-social resources showed a partial mediating effect between preparation for old age of the past and active aging level. The research implications are as follows. First, this research makes an effort to approach the concept of preparation for old age with an integrated perspective through making a construct by entire preparation types. Second, it will attempt to verify the relationship between preparation for old age in the past and active aging in terms of multi-dimension is meaningful. Third, this research reveals the function of psycho-social resource, self-efficacy and social support within the relationship. As far as the partial mediating effect is concerned, preparation for old age education for the middle-aged class should be modified as a decent field to enhance of the elderly.