• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.642-649
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• 2016

Important safety parameters such as the fuel temperature coefficient (FTC) and the power coefficient of reactivity (PCR) of the CANada Deuterium Uranium (CANDU-6) reactor have been evaluated using the Monte Carlo method. For accurate analysis of the parameters, the Doppler broadening rejection correction scheme was implemented in the MCNPX code to account for the thermal motion of the heavy uranium-238 nucleus in the neutron-U scattering reactions. In this work, a standard fuel lattice has been modeled and the fuel is depleted using MCNPX. The FTC value is evaluated for several burnup points including the mid-burnup representing a near-equilibrium core. The Doppler effect has been evaluated using several cross-section libraries such as ENDF/B-VI.8, ENDF/B-VII.0, JEFF-3.1.1, and JENDL-4.0. The PCR value is also evaluated at mid-burnup conditions to characterize the safety features of an equilibrium CANDU-6 reactor. To improve the reliability of the Monte Carlo calculations, we considered a huge number of neutron histories in this work and the standard deviation of the k-infinity values is only 0.5-1 pcm.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.1009-1029
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• 2023

Urban trees play a vital role in urban ecosystems,significantly reducing impervious surfaces and impacting carbon cycling within the city. Although previous research has demonstrated the efficacy of employing artificial intelligence in conjunction with airborne light detection and ranging (LiDAR) data to generate urban tree information, the availability and cost constraints associated with LiDAR data pose limitations. Consequently, this study employed freely accessible, high-resolution multispectral satellite imagery (i.e., Sentinel-2 data) to estimate fractional tree canopy cover (FTC) within the urban confines of Suwon, South Korea, employing machine learning techniques. This study leveraged a median composite image derived from a time series of Sentinel-2 images. In order to account for the diverse land cover found in urban areas, the model incorporated three types of input variables: average (mean) and standard deviation (std) values within a 30-meter grid from 10 m resolution of optical indices from Sentinel-2, and fractional coverage for distinct land cover classes within 30 m grids from the existing level 3 land cover map. Four schemes with different combinations of input variables were compared. Notably, when all three factors (i.e., mean, std, and fractional cover) were used to consider the variation of landcover in urban areas(Scheme 4, S4), the machine learning model exhibited improved performance compared to using only the mean of optical indices (Scheme 1). Of the various models proposed, the random forest (RF) model with S4 demonstrated the most remarkable performance, achieving R² of 0.8196, and mean absolute error (MAE) of 0.0749, and a root mean squared error (RMSE) of 0.1022. The std variable exhibited the highest impact on model outputs within the heterogeneous land covers based on the variable importance analysis. This trained RF model with S4 was then applied to the entire Suwon region, consistently delivering robust results with an R² of 0.8702, MAE of 0.0873, and RMSE of 0.1335. The FTC estimation method developed in this study is expected to offer advantages for application in various regions, providing fundamental data for a better understanding of carbon dynamics in urban ecosystems in the future.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2175-2178
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• 2012

Purpose: Definite diagnosis of follicular thyroid carcinoma (FTC) is based on the presence of capsular or vascular invasion. To date, no reliable and practical method has been introduced to discriminate this malignant neoplasm from follicular thyroid adenoma (FTA) in fine needle aspiration biopsy material. Matrix metalloproteinase-2 (MMP-2), by degrading extracellular matrix, and caspase-3, by induction of apoptosis, have been shown to play important roles in carcinogenesis and aggressive behavior in many tumor types. The aim of this study was to examine expression of MMP-2 and caspase-3 in thyroid follicular neoplasms and to determine their usefulness for differential diagnosis. Method: Sixty FTAs and 41 FTCs were analysed immunohistochemically for MMP-2 and caspase-3. Result: MMP-2 was positive in 4 FTCs (9.8%), but in none of FTAs, with statistical significance (p= 0.025). Caspase-3 was positive in 30 (50%) of FTAs and in 27 (65.9%) of FTCs. Conclusion: Our results show MMP-2 expression only in FTCs and suggest that this protein may be a useful marker to confirm diagnosis of FTC versus FTA with 100% specificity and 100% predictive value of a positive test. We failed to show any differential diagnostic value for caspase-3 in thyroid follicular neoplasms.

• Journal of the Korean Society of Costume
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• v.59 no.8
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• pp.15-25
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• 2009

The structure and material of Mang-geon from excavated tomb of Yi-ikjung in 1700', Seoul, were analyzed and identified. The Mang-geon was worn by Yi-ikjung when it is found. Until now, it is know that Mang-geon is made of horsehair, but it find out to be made of silk threads. This result verified the presence of 'sa-kyul Mang-geon' which been estimated to used only for document records. This proves Mang-geon has been produced in the silk threads as well as horsehair and human hair. The front and back of the Mang-geon was made of intertwisted silk threads by using simple linking method. Dang is constructed of looped linking method. The size of Dang is wider, which give greater flexibility to wrap top of head.

• Tunnel and Underground Space
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• v.29 no.4
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• pp.243-261
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• 2019

Microseismic monitoring technologies have been recognized for its superiority over traditional methods and are used in domestic and overseas underground mines. However, the complex gangway layout of underground mines in Korea and the mixed structure of excavated space and rock masses make it difficult to estimate the microseismic propagation and to determine the arrival time of microseismic wave. In this paper, experimental studies were carried out to determine the source location according to various arrival picking methods and dimensional conditions. The arrival picking methods used were FTC (First Threshold Cross), Picking window, AIC (Akaike Information Criterion), and 2-D and 3-D source generation experiments were performed, respectively, under the 2-D sensor array. In each experiment, source location algorithm used iterative method and genetic algorithm. The iterative method was effective when the sensor array and source generation were the same dimension, but it was not suitable to apply when the source generation was higher dimension. On the other hand, in case of source location using RCGA, the higher dimensional source location could be determined, but it took longer time to calculate. The accuracy of the arrival picking methods differed according to the source location algorithms, but picking window method showed high accuracy in overall.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.928-934
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• 2002

A natural way to cope with fault tolerant control (FTC) problems is to modify the control parameters according to an online identification of the system parameters when a fault occurs. However. due to not only difficulties Inherent to the online multivariable identification in closed-loop systems, such as modeling errors, noise or the lack of excitation signals, but also long time requirement to identify the post-fault system and implemeutation of control problems during the identification process, we propose an alternative approach based on the observer-based fault detection and isolation (FDI) and model reference adaptive control (MRAC). The proposed robust fault diagnosis method is based on a bank of observers. We also propose a model reference adaptive control with changeable reference models according to the occurred faults. Simulation results of a flight control example show the validity and applicability of the proposed algorithms.

• KSBB Journal
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• v.22 no.1
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• pp.30-36
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• 2007

The water-soluble or ethanol-soluble materials extracted from fruit bodies and cultured products (mycelium and broth) of H. erinaceum were prepared, and their inhibitory effect on acetylcholinesterase (AChE) activity from Electrophorous electricus was investigated. Inhibition of 75-85% for AChE activity at concentration of 10 mg/ml was obtained and the mechanism was due to general non-competitive inhibition. Especially, the supernatant of culture broth by ethanol treatment, exhibited a strong inhibition activity of 94% at 10 mg/ml. The samples from fruit body, mycelium and broth (supernatant and precipitate by ethanol treatment) which were extracted from H. erinaceum, were very effective to inhibit the initial stage oxidation of a linoleic acid at concentration of 0.1 mg/ml. The antioxidative activity of these samples were superior than rutin, vitamin C and tocopherol as antioxidative standards by FTC (ferric thiocyanate) method, and also showed the very strong antioxidative activity of 95% without significant difference of the samples by TBA-RS (thiobarbituric acid-reactive substance) method.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1375-1381
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• 2008

The nutritional compositions and antioxidative activities of Korean commercial blueberry and raspberry were investigated. The proximate compositions were 10.47% and 22.67% in moisture, 2.66% and 2.64% in crude protein, 2.04% and 1.67% in crude fat, 81.36% and 70.19% in nitrogen free extracts, 1.48% and 0.85% in crude fiber, and 1.99% and 1.98% in ash of blueberry and raspberry, respectively. Total phenolics content were higher in blueberry (9.028 mg/g) than in raspberry (5.340 mg/g). Major elements of blueberry and raspberry were Ca (451.34 and 97.48 mg/100 g), K (355.40 and 215.20 mg/100 g), P (321.10 and 294.04 mg/100 g), and Na (137.58 and 137.67 mg/100 g). The total amino acid contents of blueberry and raspberry were 2,011.44 mg /100 g and 2,098.82 mg/100 g, respectively. Amino acid were mainly composed of glutamic acid, aspartic acid and leucine. The DPPH and ABTS radical scavenging activities of the 80% methanol extract from blueberry and raspberry were 88.67% and 62.77%, 76.34% and 30.53% at a concentration of 5 mg/mL. The 80% methanol extract from blueberry and raspberry showed considerable antioxidative activity against reducing power in dose-dependent manner. Antioxidative activities using $\beta$-carotene-linoleate and FTC method were twice higher in blueberry than raspberry.

• Korean Journal of Plant Resources
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• v.20 no.2
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• pp.177-184
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• 2007

Bioactive substances, antioxidant activities and tyrosinase inhibitory activities of seed extracts were evaluated to discover new functional materials, using 13 edible or medicinal plants. Total polyphenol and flavonoid contents were highest in Taxus cuspidata, with $57.51mg{\cdot}g^{-1}\;and\;7.98mg{\cdot}g^{-1}$, respectively. Seed extract of Vitis coignetiae${\times}$Vitis labruscana($RC_{30}=0.030mg{\cdot}ml^{-1}$) was found to be the most effective in DPPH radical scavenging test, and the highest ABTS radical scavenging activity was shown in Diospyros lotus($RC_{30}=0.044mg{\cdot}ml^{-1}$). Inhibitory effects on peroxidation of linoleic acid determined by ferric thiocyanate (FTC) method were similar to BHT in Diospyros kaki, Diospyros lotus, Magnolia officinalis, Styrax obassia, Vitis coignetiae, Vitis coignetiae${\times}$Vistis labruscana, Zizyphus jujuba, Zizyphus jujuba var. inermis. For the inhibition against mushroom tyrosinase, Diospyros kaki, Diospyros lotus, Poncirus tritoliata, Prunus serrulata var. spomtanea, Zizyphus jujuba and Zizyphus jujuba var. inermis exhibited inhibitory activity, and especially Diospyros lotus showed the strongest inhibition.

• Food Science and Preservation
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• v.11 no.3
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• pp.358-363
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• 2004

This study was performed to evaluate the antioxidant effect of Prunus salicina Lindl. cv. Soldam at different growth stages (sample 1-8). Previous studies shows that this fruits possess hematopoiesis effect, osteoporosis prevention, and antimutagenic effects. Prunus salicina Lindl. cv. soldam was picked in every 5 days from the 40th day before harvesting date for marketing in Gimcheon, Gyeongbuk. The fruits at different growth stages (sample 1-8) were extracted with 60$\%$ acetone and chlorophyll in the extracts was removed. In proximate compositions, the contents of moisture of sample 1, 5, 8 were 88.52, 87.01, 83.56$\%$ ; crude ash were 7.12, 3.35, 3.57$\%$ ; crude protein were 7.52, 5.55, 3.85$\%$ ; crude fat contents were 3.20, 0.99, 5.15$\%$, respectively. The contents of total polyphenols and condensed tannin in the acetone extracts from sample 1, 5, 8 were 10.67, 4.05, 2.57$\%$, and 8.36, 3.11, 1.88$\%$, respectively. The antioxidantive effect of acetone extracts from immature fruits showed strong scavenging effect on DPPH free radicals. The RC$_{50}$ values of the extracts from sample 1, 2 were 2.23, 9.70 $\mu$g/mL, respectively while those of butylated hydroxyanisole (BRA) was 5.25 $\mu$g/mL. The extracts from immature fruits showed over 85$\%$ inhibition on peroxidation of linoleic acid at 100 $\mu$g/mL as determined by both the ferric thiocyanate (FTC) and the thiobarbituric acid (TBA) method.