• Corrosion Science and Technology
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• v.4 no.6
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• pp.236-241
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• 2005

Hydrogen induced cracking (HIC) is one of the hydrogen degradation phenomena of linepipe steels caused by $H_2S$ gas in the crude oil or natural gas. However, NACE TM0284-96 standard HIC test method is hard to satisfy the steel requirements for sour service application since it uses more severe environmental conditions than actual conditions. Therefore, in order to use steels effectively, it is required to evaluate HIC resistance of steels in the practical range of environmental severity. In this study, HIC resistance of two high strength low alloy (HSLA) steels being used as line pipe steels was evaluated in various test solutions with different $H_2S$ pressures and pH values. The results showed that the key parameter affecting crack area ratio (CAR) is $H_2S$ partial pressure of test solution when the pH value of test solution is not over 4. Hydrogen diffusivity was not a constant value, but it was rather affected by the hydrogen ion concentration (pH value) in the solution.

• Journal of information and communication convergence engineering
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• v.18 no.2
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• pp.88-93
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• 2020

The IEEE 802.11p-based wireless access in vehicular environments (WAVE) [1] communication is a method used exclusively for wireless communication on the road. This technique enables information sharing not only among moving vehicles but also between vehicles and infrastructure [2]. As part of WAVE communication, data is transmitted to and from vehicles in motion; in this case, it is difficult to determine the channel accurately in an outdoor environment owing to the Doppler shift [3]. This paper proposes a new channel estimation scheme for enhancing the reception performance of the IEEE 802.11p-based WAVE system. The proposed technique obtains the initial channel value by estimating the least square in the time domain by inserting a pilot signal for channel estimation into the IEEE 802.11p virtual subcarrier. Subsequently, a least mean square algorithm is applied to the initial channel value to update the estimated channel value. The simulation results obtained using the proposed channel estimation technique confirm its remarkable efficiency.

• International Journal of Advanced Culture Technology
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• v.7 no.2
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• pp.201-208
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• 2019

The purpose of this study was to investigate the effect of type of values on coping stress through communication ability. The data for the study were collected from February 1 to 15, 2019, and the participants were collected through online questionnaires in the twenties who voluntarily participated in the study. The final data used in this study were 324. The research method was cross - sectional questionnaire survey. The analysis was done using SPSS 18.0, descriptive statistics, Pearson correlation, multiple regression and median effect analysis. A total of 324 people participated in the study, 38% of men and 62% of women were female. The results of this study showed that the collectivism values were positively correlated with individualism values (r = .224, p<0.01), emotional stress coping style (r = .266, p <), And emotion - centered stress coping was correlated with problem - oriented stress coping (r = .369, p <0.01). Those who had a collectivist value had a significant influence on the type of problem - centered stress coping(${\beta}=.271$, p<0.01), and the communication ability showed a perfect mediating effect($R^2=.310$,${\beta}=.113$, p>0.05). According to the results of this study, stress coping in the twenties suggests a program that fosters individualized communication ability.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.2
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• pp.53-59
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• 1986

On the slamming analysis of ship design the data for the impact pressure acted on the forward bottom of a ship are needed. Furthermore impact pressure is given by the function of both the hull form coefficient and relative velocity. In this papper. a simplified method to estimate hull form coefficient by perso;,al computer (p. c.) is studied. This numerical analysis was applied to the model of the Mariner type. and then the result by the p. c. was compared with that by IBM 7090 computer. Main results obtained are as follows: 1. The result by the developed p. c. method had fairly good agreement with that by conventional large computer (IBM 7090) within 2% error. 2. This developed method' by p. c. may be applied to the initial estimation of the K-value because of the close agreement between the ship lines by the results of p. c. and that of input.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.201-209
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• 2014

Obstructive sleep apnea syndrome(OSAS) is a respiratory disease caused by partial or complete obstruction of the upper airway during sleep. In this paper, we proposed the optical flow method to analyze the upper airway dynamic changes during respiration for children with OSAS and control subjects. We compared the absolute value of difference between inspiration and expiration for airway area analysis method and optical flow method for 5 children with OSAS and 6 control subjects. From the statistical analysis, airway area analysis method and optical flow method are statistically significant at the 0.1 (p value is 0.0977) and 0.01 (p value is 0.0011) significance level respectively. From this simulations, the optical flow method could provide more accurate information to diagnose the OSAS patients than the traditional airway area analysis method.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.221.2-222
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• 2003

The relative retrogradation of Jeungpyun investigated with different millimg methods of rice flour. The relative retrogradation of Jeungpyun was reduced in order that of W-C, W-P, D-M, D-J in DSC(Differential Scanning Calorimetry) method while W-C, D-M, D-J, W-P in Diastase method. In wet milling method, the relative retrogradation of Jeungpyun by Pin mill(W-P) was lower than Jeungpyun by colloid mill(W-C). In dry milling method, the relative retrogration of Jeungpyun by jet mill(D-J) was lower than Jeungpyun by micro mill(D-M). The relative retrogradation of Jeungpyun by DSC method was similar to the Diastase method. The relative retrogradation of Jeungpyun was decreased with decreasing particle size and setback value for amylogram and increasing damaged starch.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.113-117
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• 2016

Quantile regression is an efficient method for predicting and estimating the relationship between explanatory variables and percentile points of the response distribution, particularly for extreme percentiles of the distribution. To study the relationship between urbanization and cancer morbidity, we here applied quantile regression. This cross-sectional study was conducted for 9 cancers in 345 cities in 2007 in Iran. Data were obtained from the Ministry of Health and Medical Education and the relationship between urbanization and cancer morbidity was investigated using quantile regression and least square regression. Fitting models were compared using AIC criteria. R (3.0.1) software and the Quantreg package were used for statistical analysis. With the quantile regression model all percentiles for breast, colorectal, prostate, lung and pancreas cancers demonstrated increasing incidence rate with urbanization. The maximum increase for breast cancer was in the 90th percentile (${\beta}$=0.13, p-value<0.001), for colorectal cancer was in the 75th percentile (${\beta}$=0.048, p-value<0.001), for prostate cancer the 95th percentile (${\beta}$=0.55, p-value<0.001), for lung cancer was in 95th percentile (${\beta}$=0.52, p-value=0.006), for pancreas cancer was in 10th percentile (${\beta}$=0.011, p-value<0.001). For gastric, esophageal and skin cancers, with increasing urbanization, the incidence rate was decreased. The maximum decrease for gastric cancer was in the 90th percentile(${\beta}$=0.003, p-value<0.001), for esophageal cancer the 95th (${\beta}$=0.04, p-value=0.4) and for skin cancer also the 95th (${\beta}$=0.145, p-value=0.071). The AIC showed that for upper percentiles, the fitting of quantile regression was better than least square regression. According to the results of this study, the significant impact of urbanization on cancer morbidity requirs more effort and planning by policymakers and administrators in order to reduce risk factors such as pollution in urban areas and ensure proper nutrition recommendations are made.

• Food Science of Animal Resources
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• v.34 no.3
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• pp.273-279
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• 2014

The objective of this study was to investigate the effects of the packaging method on the lipid and protein oxidation, and color in aged top round from Hanwoo (Korean native cattle) for 14 d at $4^{\circ}C$. Catalase activity was the highest (p<0.05) in vacuum packaging (VP) treatment during storage, and was higher (p<0.05) in 50% Ox-MAP and 50% Ox-MAP+vacuum skin packaging (VSP) treatments than in other treatments at d 14. Superoxide dismutase activity was higher (p<0.05) in VP, 50% Ox-MAP, and 50% Ox-MAP+VSP treatments than in other treatments at d 14. During storage, total antioxidant activity was the highest (p<0.05) in VP treatment and was higher (p<0.05) in 50% Ox-MAP+VSP treatment than in 80% Ox-MAP treatment. TBARS value was the lowest (p<0.05) in VP treatment during storage and was lower (p<0.05) in 50% Ox-MAP and Ox-MAP+VSP treatments than in 80% Ox-MAP and Ox-MAP treatments, respectively. Carbonyl content was the lowest (p<0.05) in VP treatment from 10 d. From 7 d, the $a^*$ value was the highest (p<0.05) in VP treatment and was higher (p<0.05) in 50% Ox-MAP and 50% Ox-MAP+VSP treatments than in other treatments. The $b^*$ value was the highest (p<0.05) in VP treatment from 3 d, and was higher (p<0.05) in 80% Ox-MAP+VSP, 50% Ox-MAP, and 50% Ox-MAP+ VSP treatments than in 80% Ox-MAP treatment at d 14. Therefore, VP improved the oxidation and red color stabilities in stored-aged top round compared with Ox-MAP. In addition, 50% Ox-MAP improved the lipid oxidation and red color stabilities compared with 80% Ox-MAP, and its inhibitory effect on lipid oxidation was enhanced by combination with VSP.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.2
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• pp.34-39
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• 2009

The traditional Korean hand-made papers (Hanji) were dyed with colorant extracted from flowers of Sophora japonica L.(pagoda tree), and the effect of various dyeing factors (mordant, mordanting method, pH of dyeing solution, etc.) on colors and K/S values of the dyed Hanji was investigated. Changing mordant affected the color of dyed Hanji. Mordanting with alum, copper acetate made the color of dyed Hanji more yellow, but dyed Hanji mordanted with $FeCl_2$ had dark olive color. The K/S value of the dyed Hanji mainly depended on the pH of the dyeing solution and mordanting method. It was found that sim-mordanting with alum was timesaving and effective dyeing method. The dyed Hanji sim-mordanted with alum had the highest K/S value at low pH (about 4).

• Journal of Environmental Science International
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• v.13 no.9
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• pp.807-817
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• 2004

The modified biochemical oxygen demand (MBOD) were conducted to evaluate the water quality and fertility in the Mangyeong river from november 2002 to april 2003. MBOD method was used to evaluate algal growth potentials and their limiting factors. MBOD depends on the amount of available inorganic nutrient and organic substrate during 5-day incubation in the dark condition at $20^{\circ}C.$ The MBOD assay depends on inorganic nutrients such as phosphorus and nitrogen as well as reduced carbon as called MBOD, MBOD-P, and MBOD-N, respectively. The concentration of pollutants were in the range of 3.08～48.36 mg/L for COD. The concentration of nutrients were in the range of 0.37～111.62 mg/L for dissolved inorganic nitrogen (DIN) and 0.00～1.03 mg/L for dissolved inorganic phosphorus (DIP). The results of MBOD bioassay showed that the MBOD, MBOD-P and MBOD-N values were 15～173 mg $O_2/L,$ 13～165 mg $O_2/L$ and 66～175 mg $O_2/L$ ranges, respectively. The MBOD values are found to be the highest in Iksan River and the lowest in Hari River throughout the Mangyeong River. The relationships of MBOD, MBOD-P and MBOD-N in MBOD method were generally found in MBOD$\risingdotseq$ MBOD-P$\risingdotseq$MBOD-N. But the result of Gosan was appeared to MBOD$\risingdotseq$MBOD-N > MBOD-P. The MBOD-N value was higher 3 to 5 times than the MBOD-P value in the Gosan station. The algal growth potentials expressed as the concentration of chlorophyll-a were maximum 20 times more than algal biomass in the water column.