• Journal of Conservation Science
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• v.33 no.2
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• pp.107-120
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• 2017

This research involves a gilding experiment using plum acid that has previously been reported to restore Geumdongsamjonpanbul excavated from Wolji, Gyeongju. Chromaticity analysis revealed that the yellowness of the samples was high, and the samples treated with acid for more than 10 minutes showed high brightness. SEM studies revealed that the sample subjected to amalgam application and immediate heating was rarely gilded with gold. When the amalgam application time was longer than 36 h, the gold layer observed was uneven. Therefore, the optimum amalgam application time was 12-24 h. EDS analysis showed that mercury content was ~5 wt.% for samples with an acid treatment time of 20 min, lower than that in other samples. Gold gilding was successful for the sample with amalgam application time of 24 h and acid treatment time of 20 min. This sample showed the high-resolution XPS peak corresponding to Au and retains a little Hg compared with the other samples. In other words, experimental and analytical results using plum acid showed that gilding was successful when acid treatment time was 20 min and amalgam application time was 24 h. Based on these results, Geumdongsamjonpanbul excavated from Wolji, Gyeongju can be restored.

• Asian Journal of Atmospheric Environment
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• v.9 no.4
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• pp.247-258
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• 2015

Exposure of high concentration of ground-level ozone (GLO) can trigger a variety of health problems including chest pain, coughing, throat irritation, asthma, bronchitis and congestion. There are substantial human and animal toxicological data that support health effects associated with exposure to ozone and associations have been observed with a wide range of outcomes in epidemiological studies. The aim of the present study is to estimate the spatial distributions of GLO using geostatistical method (ordinary kriging) for assessing the exposure level of ozone in the eastern part of Texas, U.S.A. GLO data were obtained from 63 U.S. EPA's monitoring stations distributed in the region of study during the period January, 2012 to December, 2012. The descriptive statistics indicate that the spatial monthly mean of daily maximum 8 hour ozone concentrations ranged from 30.33 ppb (in January) to 48.05 (in June). The monthly mean of daily maximum 8 hour ozone concentrations was relatively low during the winter months (December, January, and February) and the higher values observed during the summer months (April, May, and June). The higher level of spatial variations observed in the months of July (Standard Deviation: 10.33) and August (Standard Deviation: 10.02). This indicates the existence of regional variations in climatic conditions in the study area. The range of the semivariogram models varied from 0.372 (in November) to 15.59 (in April). The value of the range represents the spatial patterns of ozone concentrations. Kriging maps revealed that the spatial patterns of ozone concentration were not uniform in each month. This may be due to uneven fluctuation in the local climatic conditions from one region to another. Thus, the formation and dispersion processes of ozone also change unevenly from one region to another. The ozone maps clearly indicate that the concentration values found maximum in the north-east region of the study area in most of the months. Part of the coastal area also showed maximum concentrations during the months of October, November, December, and January.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.603-611
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• 2020

A porous material which can contain liquid perfume was manufactured by adding 1~4 wt% of polysiloxane into a composite containing 20 ㎛ Ag powder and 30 wt% of 53 ㎛ salt, sintering for 60 min at 750℃, and melting salt selectively. The changes in pore, hardness, and microstructure were confirmed according to the polysiloxane content both before and after sintering. The manufactured silver liquid container was formed with open pores both before and after sintering, and the container shrunk by 2~7 % in both perpendicular and parallel directions after sintering. Vickers hardness was increased after sintering and was doubled when 2 wt% of polysiloxane was added. In case of the microstructure, the surface condition of the silver liquid container became darker according to the polysiloxane content, and the pore size was decreased from 50 ㎛ to under 10 ㎛. The composition distribution result revealed an even distribution when 2 wt% of polysiloxane was added but uneven distribution when over 3 wt% of polysiloxane was added due to decreased hardness by cluster. Therefore, the addition of an appropriate amount of 2 wt% polysiloxane reinforced the porous silver with open pores to offer application for jewelry usage.

• Journal of KIISE:Information Networking
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• v.35 no.1
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• pp.21-33
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• 2008

The wireless sensor nodes near to the fixed sink node suffer from the quickly exhausted battery energy. To address this problem, the mobile sink node has been applied to distribute the energy consumption into all wireless sensor nodes. However, since the mobile sink node moves, the data collection scheduling scheme is necessary for the sink node to receive the data from all sensor nodes as fair as possible. The application fields of wireless sensor network need the real-time processing. If the uneven data collection occurs in the wireless sensor network, the real-time processing for the urgent events can not be satisfied. In this paper, a new method is proposed to support the lair data collection between all sensor nodes. The proposed method performs the scheduling algorithm based on the resident time of the sink node staying in a radius of communication range and the amount of data transferred already. In this paper, the proposed method and existing data collection scheduling schemes are evaluated in wireless sensor network with the mobile sink node. The result shows that the proposed method provides the best fairness among all data collection schemes.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.5 no.1
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• pp.17-25
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• 2011

This paper aims to find the optimal control gain for enhancing the convenience of electric walking frames and design a control algorithm. With the recent advances in medical technology, there has been a rapid increase in the aging population and a variety of mobile walking frames have been developed for improvement of the quality of life. However, the manual walking frames of such mobile aids don't have any electric motor which helps facilitate elderly users' walking and thus are not efficient enough for the old people of weak strength to use especially when moving on uneven surfaces such as slopes or thresholds. The types of electric walking frames have been developed to overcome such inefficiency. Electric walking frames require users' control operations for motor driving unlike manual frames. Therefore, when they are not properly handled, it causes considerable inconvenience to their users. The present study compared the electric walking frames with manual ones in terms of operational convenience and attempted to improve the user convenience of walking frames varying the control value for user convenience based on certain standards. This paper presented a haptic sensor designed to recognize the will to walk and measure the degree of convenience and proposed a control algorithm for improvement of convenience. For user convenience, this paper evaluated the relative convenience of walking frames in view of changing differences between the center of vehicle (COV) and the center of position (COP). With the employment of an electric walking frame and a new measuring method, all the processes were experimentally tested and validated.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.103-115
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• 2011

Concrete slab curls and warps due to the uneven distribution of temperature and moisture and as the result, internal stress develops within the slab. Therefore, environmental loads must be considered in addition to the traffic loads to predict the lifespan of the concrete pavement more accurately. The strength of the concrete slab is gradually decreases to a certain level at which fatigue cracking is generated by the repetitive traffic and environmental loadings. In this study, a new fatigue regression model was developed based on the results from previously performed studies. To verify the model, another laboratory flexural fatigue test program which was not used in the model development, was conducted and compared with the predictions of other existing models. Each fatigue model was applied to analysis logic of cumulative fatigue damage of concrete pavement developed in the study. The sensitivity of cumulative fatigue damage calculated by each model was analyzed for the design factors such as slab thickness, joint spacing, complex modulus of subgrade reaction and the load transfer at joints. As the result, the model developed in this study could reflect environmental loading more reasonably by improving other existing models which consider R, minimum/maximum stress ratio.

• Food Science and Preservation
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• v.23 no.3
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• pp.422-431
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• 2016

To investigate the causes of the thermal deformations of packaging materials when microwave-heating ready-to-eat sauce products packaged in stand-up pouches, patterns of temperature changes were determined using an infra-red thermal imaging camera, a thermo-sensitive tape, and a fiver-optic thermometer. The temperature distributions of spicy chicken sauce and Indian curry samples in a stand-up pouch were found to be uneven during micrewave heating. A sharp increase in the temperature was detected, especially above the filling layers and in the corners of sealing layers of the package. The temperature measurements using an infra-red thermal imaging camera are restricted to the surface, and therefore might underestimate the actual temperature. Using a thermo-sensitive tape, temperature up to $200^{\circ}C$ were measured in the spicy chicken sauce sample showing package deformation. When the temperature is measured using a fiber-optic thermometer, it is crucial to have precise sensor performance to accurately measure the temperature in a narrow hot-spot area of the package. In this experiment, the fiber-optic thermometer was attached to a GaAs crystal sensor, which obtained more sensitive and accurate temperature measurements than those by a convectional sensor.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1335-1342
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• 2014

Shallow water depths were estimated using Compact Airborne Spectrographic Imager (CASI)-1500 and mapped to analyze the bottom bathymetry changes due to the rip currents in Haeundae beach, South Korea for the first time. The depths were estimated empirically using the maximum reflectances from 420nm to 597nm wavelength of CASI and 47 in situ water depth measurements, which were compared with ground-truth bathymetry measurements. The comparisons showed that the RMSE was 1.1m with a correlation coefficient of 0.76. In addition, CASI imagery showed remarkably detailed bottom features, especially those resulting from the rip currents within the beach. Two different channels carved by the rip current were analyzed and characterized with respect to the width and slope compared to surrounding regions. While the west side of the channel showed a wide and gentle slope, the east side of the channel showed a narrow and steep slope. The estimated bathymetry map revealed that the uneven offshore bottom features were related to the transport and accumulation of sediments by the rip current, which reaches hundreds of meters offshore. Accordingly, the accumulated sediments were estimated by adding topography changes compared to the depths of the non-rip current regions. The sediments were accumulated in off channels as much as almost twice the amount of annual sand supplements along the Haeundae beach.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2002.10a
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• pp.53-67
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• 2002

As in the past, we are concerned today with the magnitudes of mineral resources and the adequacy of these resources to meet future needs. In looking at global resource issues, we should consider the need for the resource, its supply, and the environmental consequences of using it. The need for a resource can become a resource dependency, especially as the global population expands and each of us becomes increasingly dependent upon hundreds of natural materials. Therefore, our great mineral consumption makes the human population a true 'Geologic Force', which will be even more significant in the future when the global population is projected to reach alarming proportions. Although our supplies of mineral resources probably will be sufficient for the 21s1 century, the uneven distribution of minerals in the Earth's crust almost certainly will continue to be a major problem The most likely result will be major shifts in both prices and sources of supply of many mineral resources. As for energy resources, we must avoid an obsessive dependency on one fuel and expand instead to thor energy resources. Finally, because the use of resources affects the environment, we need to focus on resource exploitation and global pollution, particularly in regard to ground water and arable land. We must manage our resources so as to be in balance with our environment. And the accelerated industrialization of South Korean economy over the last three decades has resulted in the mass consumption of nuneral commodities. South Korea has around 50 useful mineral commodities for the mineral industry, among 330 kinds of minerals described. The component ratio of the mining industry sector of the gross national production(GNP) in South Korea dropped from $1.2\%\;in\;1971\;to\;0.34\%$ in 1997 due to the rapid growth of other industries In the countxy. During the period from 1971 to 1997, the average growth rate of mineral consumption in South Korea was $9.13\%$ yearly and that of GNP per capita was $14.97\%$. The mineral consumptions per capita showed a continual Increase during the last 30 years as follows(parenthesis. GNP per capita): 0.99 metric tons in 1971($\$289$), 3.83 metric tons in 1989($\$5,210$), 6.11 metric tons in 1995 ($\$10,037$), and 6.66 metric tons in 1997($9,511). The total amount of mineral consumption in South Korea was 33 million tons of 32 mineral commodities in 1971, and 306 million metric tons of 47 mineral commodities In 1997.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1715-1720
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• 2013

Background: The discovery that microRNAs (miRNAs) regulate proliferation, invasion and metastasis provides a principal molecular basis of tumor heterogeneity. Microvessel distribution is an important characteristic of solid tumors, with significant hypoxia occurring in the center of tumors with low blood flow. The distribution of miR-374a in breast tumors was examined as a factor likely to be important in breast cancer progression. Methods: Breast tissue samples from 40 patients with breast cancer were classified into two groups: a highly invasive and metastatic group (HIMG) and a low-invasive and metastatic Group (LIMG). Samples were collected from the center and edge of each tumor. In each group, six specimens were examined by microRNA array, and the remaining 14 specimens were used for real-time RT-qPCR, Western blot and immunohistochemical analyses. Correlation analysis was performed for the miRNAs and target proteins. Follow-up was carried out during 28 months to 68 months after surgery, and survival data were analyzed. Results: In the LIMG, the relative content of miR-374a was lower in the center of the tumor than at its edge; in the HIMG, it was lower at the edge of the tumor, and miR-374a levels were lower in breast cancer tissues than in normal tissues. There was no difference between VEGF-A and VCAM-1 mRNA levels at the edge and center of the tumor; however, we observed a significant difference between VEGF-A and VCAM-1 protein expression levels in these two regions. There was a negative correlation between miR-374a and target protein levels. The microvessel density (MVD) was lower in the center of the tumor than at its edge in HIMG, but the LIMG vessels were uniformly distributed. There was a significant positive correlation between MVD and the number of lymph node metastases (Pearson correlation, r=0.912, P<0.01). The median follow-up time was 48.5 months. LIMG had higher rate of disease-free survival (100%, P=0.013) and longer median survival time (66 months) than HIMG, which had a lower rate of 75% and shorter median survival time (54 months). Conclusions: Our data demonstrated miR-374a to be differentially distributed in breast cancer; VEGF-A and VCAM-1 mRNA had coincident distribution, and the distribution of teh respective proteins was uneven and opposite to that for the miR-374a. These data might explain the differences in the distribution of MVD in breast cancer and variation in breast cancer prognosis.